It’s 4:30pm on a Friday afternoon. You still haven’t finished your notes from clinic, there are scripts waiting to be signed, and you’re hoping to get through it all before handover. But your pager goes off:

“Please review Mrs Smith in bed 16, complaining of 8/10 pain.”

Mrs Smith has been in and out of the hospital for weeks; a complex polytrauma patient with severe left foot pain in the context of newly diagnosed CRPS. She’s known to multiple teams, has a well-documented pain plan from the pain service, and you’ve already reviewed her twice today for pain.

Before you even walk into the room, there’s a familiar thought:  What am I actually going to do that hasn’t already been done?

These reviews are incredibly challenging – not because we don’t know the medications, but because we’re often unclear on what success even looks like. We vaguely understand that managing these patients isn’t just about adjusting analgesia. It’s about how we approach the conversation: how we listen, what we validate, and how we set expectations in a situation where there often isn’t a simple fix. So what do you do next?

Step 1. Do not ignore the page and wait for the nurses to page again (hopefully when the cover resident takes over).
It’s tempting to delay this review and hope it gets handed over. Clinical inexperience and workload both push us in that direction. But delaying these reviews rarely helps. 

Recently on the paediatrics ward, I started a cover shift to a parent-initiated MET call for pain in a patient on a PCA who had lost IV access. While re-siting the cannula was already the priority for the evening medical team, the parent had no clear sense of when (or if) this might happen and was left watching their child in pain. What should have been a straightforward procedural review quickly escalated into a more complex situation requiring longer discussions, additional documentation, and increased nursing support.

When a patient familiar with chronic pain asks for help, it usually means the current plan isn’t working. Leaving it escalates the situation and signals to the patient that no one is listening. 

Step 2. Enter with an open mind. 

We are not strangers to cognitive bias in medicine. It is easy to get bogged down by the things we think we know. It is far too easy to rule out important differentials before we have all the clinical evidence and, as uncomfortable as it is to admit, it is easy to dismiss a patient before we have even entered the room. At times, I find it helpful to approach the interaction as a blank slate. 

In practice, this can be as simple as letting the patient speak uninterrupted for a couple of minutes. Evidence suggests that up to 78% of patients do not speak for longer than 2 minutes when allowed to speak without interruptions, and often, what they say in this time can reframe the entire objective of the review (Kreijkamp-Kaspers & Glasziou, 2012, pg909).

I’ve found open ended questions can help reset the conversation:

• “What’s different about today?”
• “What were you hoping I could help with?”

Additionally, taking a moment to ask “what if it’s something else?” has changed my management more than once. I once revisited a non-English speaking patient’s abdominal pain, previously attributed to chronic constipation, with a formal interpreter service and uncovered a urinary tract infection on a day she would have otherwise been discharged.

Step 3. Don’t be afraid to treat your patient, and escalate early if you think you can’t.

Severe pain can make history taking and examination tricky. In some situations, it may be more helpful to offer a stat or PRN dose of rapid-onset analgesia before attempting a detailed assessment. This can create enough space for a more meaningful review, rather than trying to assess a patient who is too distressed to engage.

At the same time, consider whether you may be walking into a pain crisis that requires early escalation with an urgent clinical review or MET call. Managing acute pain in patients already on significant multimodal regimens can be daunting, and it’s not something you need to manage alone.

Step 4. Acknowledge, reassure, and validate. 

Managing acute on chronic pain challenges our ability to troubleshoot complex clinical dilemmas, which often do not have satisfying solutions. It’s uncomfortable to acknowledge a symptom without being able to offer a quick fix, but this is often a hidden barrier to a meaningful and productive conversation. Simple acknowledgements such as “It sounds like today has been particularly difficult” can go a long way in letting someone know you are seeing them, that you believe them. Validation doesn’t have to mean agreeing with everything said, but rather reassuring a patient that their lived experience is an important part of the equation too.

Step 5. Set expectations!

The best pain reviews I’ve seen have been honest and a bit humble. These conversations can go either way. I’ve seen them escalate into full-blown arguments (and even a code grey once!), and I’ve also seen a single conversation completely change how the rest of the admission goes. A lot of that comes down to expectations.

One thing I’ve taken from discussions with various pain specialists is to avoid overpromising. Most of the time, we’re not going to make someone pain-free, and not all patients know what the end point of inpatient treatment may look like without a transparent discussion. The NICE guidelines for shared decision-making recommend early discussion of the patient’s goals for treatment and clarification of any misconceptions they might hold (NICE, 2021). 

Simple things like:

• “We might not be able to get rid of the pain completely, but we’ll try to make it more manageable.”

It also helps to be upfront about the longer-term plan:

• “We can try these medications to settle things over the next few days, but we’ll need to start weaning them before you go home.”

In my experience, having this conversation early saves you or an unsuspecting colleague from having a much harder one later.

Step 6. Come up with a plan, knowing that it may fail. 

I find it helpful to frame each management plan as a trial run: all possible options are weighed collaboratively, but only one distinct route is chosen by the end of the review. For example, many patients tend to insist on premature escalation of opioids. While this is not necessarily always appropriate in the first instance, especially for patients being overseen by a pain service, it can be reassuring to let them know that there will be a plan for staged assessment of effect and that medication changes are still on the table for discussion depending on how things progress. 

One situation where this negotiation process comes up often is when I’m reviewing patients that have declined simple analgesia, and usually this is followed by a “paracetamol never works for me.” While I’ve come across the odd patient or two who are receptive to explanations around the analgesic ladder and multimodal analgesia, most patients just prefer simplicity. One phrase I tend to reuse often is:

• “Worst case scenario, the paracetamol won’t do anything. Best case, it takes the edge off while we figure out what else we can do, while giving me more information to work with.”

In my experience, setting it up this way makes the next review easier, for both you and the patient. It turns the interaction into a shared process that they understand, rather than a single moment where you’re expected to get everything right.

In summary,

In 2020, the IASP revised their definition of pain as being “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage”, taking into account the subjective and personal nature of pain that is influenced by not only biological factors, but also psychosocial factors (IASP, 2020). Patients in pain present in vastly different ways. 

The above suggestions won’t suit every patient’s communication style, but it is not possible to communicate without first starting a conversation. And it is not possible to hold a conversation without listening to what the person in front of you needs.  

Some days it will feel like your patient hates you and the entire hospital no matter what you try. Many patients will find these discussions frustrating, while some need you to acknowledge that their experience is real and difficult. Some patients like to know about every piece of the puzzle, while others are just waiting for someone who can subtract all the medical jargon from the details that matter. Regardless, all patients deserve to be spoken to in a language they can understand.

References

IASP Announces Revised Definition of Pain – International Association for the Study of Pain. (2020, July 16). International Association for the Study of Pain. Retrieved April 1, 2026, from https://www.iasp-pain.org/publications/iasp-news/iasp-announces-revised-definition-of-pain/

Kreijkamp-Kaspers, S., & Glasziou, P. (2012, November). A is for aphorism. The power of silence. Australian Family Physician, Volume 41(11), 909. https://www.racgp.org.au/afp/2012/november/a-is-for-aphorism

NICE. (2021, June 17). National Institute for Healthcare and Excellence. Shared decision making. https://www.nice.org.uk/guidance/ng197/chapter/Recommendations#putting-shared-decision-making-into-practice

Purpose of the pre-anaesthetic assessment:

• Identify patients who have increased peri-operative risk;
• Diagnose, assess, and optimise patient comorbidities to minimise peri-operative risk;
• Plan and prepare for the patient’s perioperative journey;
• Encourage patient-centred discussion regarding risk and benefit of surgery and to reach a decision on whether to proceed or delay/cancel.

The structure and depth of the preoperative anaesthesia assessment will vary depending on the severity and stability of the patient, the urgency (elective versus emergency) and risk profile (low risk vs high risk) of the surgery. However, a general structure is always required to encapsulate the key domains imperative for perioperative planning. There is no fixed method, and juniors are encouraged to observe different styles used by perioperative clinicians and adopt one’s own. Here we present the key areas that should be explored during a pre-operative assessment:

1. Detailed History
   1. Anaesthetic history
   2. Past medical history, with specific focus on cardiovascular and respiratory systems
   3. Medication history
   4. Social history & functional status
2. Targeted examination
   1. Airway assessment
   2. Vital signs
   3. CVS exam
   4. Respiratory exam
3. Relevant investigations
4. Surgical considerations
5. Risk stratification

Detailed History

1. Anaesthetic history

• Any issues with prior anaesthetics. Any difficulties encountered with regional/neuroaxial anaesthesia.
• Family history of GA issues -> malignant hyperthermia (MH), sux apnoea (SA) due to pseudocholinesterase deficiency.
• Previous difficult airway.
• Anaphylaxis & other adverse drug reactions.
• Any unplanned HDU/ICU admission following anaesthetic?

The best predictor of intraoperative anaesthetic complications is previous complications and patterns.

Reviewing the previous anaesthesia chart can be a wealth of information. Aside from reviewing major complications and airway grade, note induction medications and doses, vasopressor, analgesics, and antiemetic use. For example, a patient with stable looking blood pressure recordings but needing large doses of metaraminol and ephedrine would be a red flag for any future inductions. Was this a mild case of anaphylaxis, or a sign of decreased cardiac function and undiagnosed heart failure?

Patients with previous anaesthetic issues such as difficult airway, anaphylaxis, MH or SA often carry letters or have electronic record prompts to alert clinicians. Any family members who have undergone genetic or allergy testing after an anaesthetic should prompt the clinician to chase further correspondences of the nature, indications and results of the investigations.

Any unplanned admission to an intensive care setting post-operatively should be reviewed, particularly if the admission was anaesthesia-related:

• Airway trauma / oedema preventing safe extubation.
• Refractory bronchospasm / aspiration event / unexplained oxygenation & ventilation defects requiring ongoing invasive positive pressure ventilation (IPPV).
• Delayed emergence requiring prolonged airway/respiratory support.
• Intraoperative haemodynamic compromise / cardiac event.
• Intraoperative neurologic event.

Etc.

2. Past medical history (PMHx)

With the advancement of perioperative medicine and minimally invasive interventions, clinicians are faced with growing numbers of multimorbid patients who are considered for surgery. This requires a succinct structure to identify and review pertinent PMHx that is relevant for the perioperative setting. Of the body systems, cardiovascular and respiratory conditions are the biggest contributors to perioperative morbidity and mortality.

With any condition that is identified, the following acronym developed by Dr. Lahiru Amaratunge can be used to elucidate important details of the condition:

SSCCT

Severity: how severe is the condition

Stability: is there any acute change recently

Cause: why has this condition occurred

Complications: has this condition led to other disease

Treatment: what is the management, is it working, what is the follow-up

Based on this, one can quickly determine the level of attention you need to pay for a particular condition.

For example, an asthmatic with 2 previous ICU admissions requiring IPPV, with an FEV1/FVC of 0.5, who has presented with new wheeze and cough, on the background of newly diagnosed pulmonary hypertension despite regular preventers and biologics, presents far greater perioperative risks than another mild but otherwise fit asthmatic who barely uses salbutamol PRN with no previous hospital admissions.

Cardiovascular disease:

-Enquire about: chest pain, syncope, orthopnoea, paroxysmal nocturnal dyspnoea, leg swelling, syncope

-Cardiac comorbidities:

• Acute coronary syndrome (ACS)/ ischaemic heart disease

• Cardiac arrhythmias

• Congestive heart failure (CCF)

• Valvular disease, in particular aortic stenosis (AS) / mitral stenosis (MS)

• Pulmonary hypertension (pulmHTN)

• Congenital heart disease

-Current management, such as coronary stenting and/or bypass, AICD/pacemaker

-Patient exercise tolerance, using validated scoring systems. E.g. Duke activity status index (DASI), metabolic equivalent tasks (MET)

-Recent cardiac investigations: ECG/Holter/TTE/stress TTE/CT cardiac/angiogram

Respiratory disease:

-Enquire about: exertional tolerance, requirement for home oxygen, hospitalisations in the past 12 months due to respiratory illness, current or former smoker?

-Recent respiratory function tests

-Illnesses of note: COPD, asthma, pulmonary hypertension, OSA

-Consider the STOP-BANG questionnaire to detect undiagnosed OSA (see below)

Other:

-Diabetes: T1 vs T2? Insulin dependent? Recent HbA1c? Recent hypo/hyperglycaemic episodes?

-Thyroid, renal, liver disease

–GORD, conditions affecting lower oesophageal sphincter function and/or delayed gastric emptying (poorly controlled reflux poses increased intra operative aspiration risk and may affect induction technique)

-Fasting status, GLP-1 agonist use?

-Conditions which may affect the cervical spine e.g. rheumatoid arthritis, ankylosing spondylitis

-In women of reproductive age, ask about possibility of pregnancy

3. Patient medications

-Medications of note include

• Anticoagulants, antiplatelets

• Cardiac, including ACEi/ARB, beta blockers

• Diabetes medications (in particular insulin, SGLT-2 inhibitors and GLP-1 agonists) [Check ANZCA’s latest guidelines https://www.anzca.edu.au/safety-and-advocacy/standards-of-practice/clinical-practice-recommendations-regarding-patients-taking-glp-1],

• DMARDs, steroids and other immunosuppressive medications

• Opioids and other long-acting opioid replacement therapies

-Consider the need for peri operative anticoagulation bridging for patients on warfarin

-Patient allergies – clarify type of reaction e.g. anaphylaxis vs medication side effect )

4. Social History & functional status

–Smoking and alcohol intake

-Other illicit drug use

-Activities of daily living, whether patient is requiring assistance with basic or complex tasks, fatigue and overall frailty

Examination

The physical exam should include a thorough airway, cardiovascular and respiratory assessment, but may include other systems depending on the patient.

Airway assessment

-Modified Mallampati score

-Thyromental distance (note if less than 6cm from thyroid notch to chin when head is extended)

-Inter-incisor distance (should be able to fit approximately 3 fingers when mouth is fully opened)

-Dentition

-Patient body habitus

-Facial hair

-Freedom of neck movements

-Jaw protrusion

The best predictor of a difficult airway is a history of a difficult airway. Recent anaesthetic charts should therefore be reviewed for previous airway grades, ease of BMV, and size of well-seated supraglottic airways.

The above are useful to identify patients with potentially difficult airways, but none in isolation provide the sensitivity nor specificity to confirm one. Nevertheless, the greater the presence of difficult airway risk factors, the more preparation is required in our airway planning. Importantly, if a genuine difficult airway is anticipated, such as those with fixed flexion deformity, extremely limited mouth opening, or retrognathia with limited jaw protrusion, an awake fibreoptic technique should be discussed with the patient and the anaesthetic team looking after the patient.

Cardiovascular

–Key vitals: BP, HR

-Chest auscultation, noting any cardiac murmurs or added heart sounds, bilateral added lung sounds

–Fluid status, noting any pedal oedema

Respiratory

-SpO2, RR, work of breathing, presence of adventitious breath sounds

Investigations

Further investigations depend on the individual patient’s comorbidities, type of surgery and time available for optimisation before their operation

Young patients undergoing low risk elective surgery may not require any investigations prior to surgery.

Bloods:

1. FBE (anaemia or thrombocytopenia, or if having major surgery)
2. EUC (eGFR, electrolytes, creatinine)
3. LFT (if known or suspected liver disease e.g. Hepatitis)
4. HbA1c (elective surgery will often be postponed for patients with poorly controlled HbA1c e.g. > 9)
5. TSH (known or suspected thyroid illness)
6. Coagulation profile (if patient takes anticoagulant medications (particularly warfarin) or haematological disease/ high bleeding risk)
7. Group and hold +- crossmatch (if blood loss anticipated)

Bedside:

1. ECG (particularly for older patients, those with cardiovascular disease or those having high risk surgery)
2. Pregnancy test: for women of reproductive age

Imaging:

1. TTE (may be considered on basis of ECG, unexplained dyspnoea, or if known or suspected CCF or valvular disease, see below)
2. CXR (not routine but may be done if suspected cardiovascular/pulmonary disease)

Other:

1. Respiratory Function Tests: to quantify airways disease (COPD/ asthma/ ILD) or if underlying respiratory illness suspected
2. Cardiac stress test: may be considered for patients with cardiovascular disease (see below)
3. Dental clearance: if concerns on airway assessment (false teeth, poor dentition etc)

Surgical Considerations

Many surgeries present their own unique challenges that anaesthetists must prepare for in our perioperative planning. As junior trainees build up their volume of practice and gain experience in the specific considerations of particular surgeries, it is often helpful to discuss with our surgical colleagues to better understand their special requirements. As always, a general structure helps to encapsulate broad surgical factors that should be included in our planning:

Space: Patient and Surgery

• How is the patient positioned? Supine, lithotomy, lateral, prone, Tredelenburg?
  • Each position is associated with cardiovascular, respiratory changes and specific pressure injury risks.
• How is the patient oriented? Head away from anaesthetic machine? Is our airway close to operative site?
  • These will present logistical challenges that need to be navigated on the day.
• Do I have access to my IV?
  • This is absolutely imperative in cases where access will be restricted, such as when arms are fully tucked or during robotic cases. Make sure you are confident with your IV, and have at least two if total intravenous anaesthesia is used.
• Where and how big is the operative site?
  • Certain regional techniques are extremely useful as a sole method of providing anaesthesia or as an adjunct to perioperative analgesia, especially in high-risk multimorbid patients or in patients where opioid minimisation is ideal. Knowing where the incisions are will help determine the best block technique.

Time: Duration and special timepoints

• How long is the surgery?
  • Duration of surgery often correlates with the complexity, degree of physiological insult, and risk of perioperative complications, such as MACE, hypothermia, major fluid shift, delayed emergence, post-operative nausea & vomiting etc.
• Are there critical moments that require special attention? Some examples include:
  • Laparoscopic surgery: pneumoperitoneum
  • Limb surgery: tourniquet tightening & release
  • Major vascular: vessel clamping & release
  • Neurosurgery: head pin, aneurysm clamping

Bleeding

Major cardiac, hepatic, vascular, obstetric and orthopaedic surgeries often carry significant bleeding risk, and appropriate perioperative management should be in place:

• Preoperative:
  • Up-to-date group and hold, with option for 2x crossmatched blood ready
  • Management of anaemia through combination of iron supplementation, optimisation of comorbidities, and blood loss minimisation (withholding of antiplatelet/anticoagulants)
• Intraoperative:
  • 2x large bore IV, hot fluid line, rapid infuser device, cell saver, blood available, ROTEM/TEG available

Special cases

• Nerve monitoring e.g. thyroidectomy, plastics reconstruction, nerve repair
  • Intraoperative avoidance of neuromuscular blockers to ensure nerve can be monitored

Risk stratification:

There are several tools which are very useful in assessing patient anaesthetic/ surgical risk. These can be used to make decisions about pre-operative optimisation and predict care requirements in the post operative period.

American Society of Anaesthesiologists Physical Status Classification System (ASA):

Useful to assess and communicate a patient’s medical comorbidities.

ASA 1 – A normal healthy patient – e.g. healthy non smoking patient

ASA 2 – A patient with mild systemic disease – e.g. current smoker, obesity, pregnancy

ASA 3 – A patient with severe systemic disease – e.g. poorly controlled diabetes, hypertension

ASA 4 – A patient with severe systemic disease that is a constant threat to life – e.g. MI or stroke < 3 months ago

ASA 5 – Moribund patient, not expected to survive the next 24 hours, with or without surgery – e.g. ruptured aortic aneurysm

ASA 6 – Declared brain dead, entering theatre for organ retrieval purposes

Major adverse cardiovascular events (MACE) represent one of the most significant complications contributing to perioperative morbidity and mortality. The presence of major cardiovascular conditions, such as ACS, CCF and arrhythmias, as well as any new, acute-on-chronic, or untreated conditions, all disproportionally increase the risk of MACE. Clinicians must consider the benefit-risk profile of delaying surgery for optimisation of these conditions.

The 2024 AAHA/ACC Guideline for Perioperative Cardiovascular Management for Non-cardiac Surgery provides a detailed flowchart to assist clinicians in deciding the most appropriate actions for patients presenting with significant cardiac comorbidities for non-cardiac surgery. To summarise:

Table 1. Adaptation of Figure 1 of 2024 AAHA/ACC Guideline for Perioperative Cardiovascular Management for Non-cardiac Surgery

Is it emergency surgery	If YES -> Proceed with surgery If NO -> Move to step 2
Does patient have either ACS (within 60 days) Unstable arrhythmias Decompensated CCF	If YES -> consider postponing surgery for management of acute cardiac condition If ACS is managed with drug-eluding stent (DES) PCI requiring cessation of 1 or more antiplatelet therapy Delay for 12 months Delay for 3 months for time sensitive surgery Also consider if any new or undiagnosed/untreated cardiac conditions If NO -> Move to step 3
Does the patient have Elevated risk for MACE based on validated risk calculators and/or Have any risk modifiers? Validated risk scores include: Revised Cardiac Risk Index (RCRI) American College of Surgeons NSQIP Surgical Risk Calculator (ACS-SRC) Risk modifiers are: Severe valvular heart disease Severe pulmHTN Elevated risk congenital heart disease Prior coronary stent/coronary bypass Recent stroke AICD or pacemaker Frailty	If Low risk score AND no modifiers -> Proceed with surgery Represents low risk procedure / low clinical risk If elevated risk score but no modifiers: Consider ECG for asymptomatic patients with no established CVD Commence or optimise guideline-directed medical therapy (GDMT) Once complete, move to step 4 If any risk modifier present: TTE for evaluation of left ventricular function, valvular pathology, or new symptoms Commence and optimise guideline-directed medical therapy And For valvular pathology, consideration of corrective intervention (valve repair/replacement) Once complete, move to step 4
Does the patient have reduced or unknown functional capacity, MET <4 or DASI <32	If NO -> Proceed to surgery If YES -> move to step 5
Will further testing change management	If NO* -> Proceed to surgery OR consider non-operative options If YES -> move to step 6
Does patient have elevated risk based on cardiac biomarkers: NT-proBNP / BNP Troponin	If NO -> Proceed to surgery If YES: Consider TTE or stress testing, and follow-up with Low risk findings -> Proceed Elevated risk -> GDMT and consideration of non-operative options Proceed w/ post-op cardiac biomarker surveillance

The 2024 AHA/ACC guideline provides a structured framework that can be adapted for any medical condition that may pose increased perioperative risk to patients. A useful mnemonic by Dr. Lahiru Amaratunge distils the steps of the 2024 AHA/ACC guideline that can be universally applied:

“Every Anaesthetist Loves Morning Coffee”

1. Emergency surgery -> proceed, with as much optimisation as possible;
2. Active condition -> if new condition or acute decompensation/deterioration, consider postponing;
3. Low risk -> if low risk procedure / low clinical risk -> proceed
4. MET >4 -> proceed
5. Cardiac investigations (or investigations relevant for the condition) -> further risk stratification and optimisation

Conclusion:

The preoperative anaesthesia assessment aims to minimise a patient’s intra and post operative risk. It encompasses a focused history, examination and select investigations. The assessment is influenced by the patient’s comorbidities, the risk of the operation, and the urgency of the operation.

Useful links:

Peri operative medication management – UpToDate

https://www.uptodate.com/contents/perioperative-medication-management

STOP-BANG Questionnaire

https://www.mdcalc.com/calc/3992/stop-bang-score-obstructive-sleep-apnea

Mallampati Score – LITFL

https://litfl.com/mallampati-score/

NSQIP Risk Calculator Tool

https://riskcalculator.facs.org/RiskCalculator/index.jsp

DASI – MDCalc

https://www.mdcalc.com/calc/3910/duke-activity-status-index-dasi#evidence

References:

Ng ACC, Kritharides L. Preoperative assessment: a cardiologist’s perspective. Aust Prescr 2014;37:188-91.https://doi.org/10.18773/austprescr.2014.079

Pang, C. L., Gooneratne, M., & Partridge, J. S. L. (2021). Preoperative assessment of the older patient. BJA education, 21(8), 314-320.

Lamperti, M., Romero, C. S., Guarracino, F., Cammarota, G., Vetrugno, L., Tufegdzic, B., … & Afshari, A. (2025). Preoperative assessment of adults undergoing elective noncardiac surgery: Updated guidelines from the European Society of Anaesthesiology and Intensive Care. European Journal of Anaesthesiology| EJA, 42(1), 1-35.

Hendrix, J. M., & Garmon, E. H. (2025). American Society of Anesthesiologists Physical Status Classification System. In StatPearls. StatPearls Publishing.

Writing Committee Members, Thompson, A., Fleischmann, K. E., Smilowitz, N. R., de Las Fuentes, L., Mukherjee, D., Aggarwal, N. R., Ahmad, F. S., Allen, R. B., Altin, S. E., Auerbach, A., Berger, J. S., Chow, B., Dakik, H. A., Eisenstein, E. L., Gerhard-Herman, M., Ghadimi, K., Kachulis, B., Leclerc, J., Lee, C. S., … Williams, K. A., Sr (2024). 2024 AHA/ACC/ACS/ASNC/HRS/SCA/SCCT/SCMR/SVM Guideline for Perioperative Cardiovascular Management for Noncardiac Surgery: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Journal of the American College of Cardiology, 84(19), 1869–1969. https://doi.org/10.1016/j.jacc.2024.06.013

Key reference:

Karamchandani et al. (2024). Tracheal intubation in critically ill adults with a physiologically difficult airway. An international Delphi study. Intensive care medicine, 50(10), 1563–1579. https://doi.org/10.1007/s00134-024-07578-2

Quick Summary

• The “physiologically difficult airway” (PDA) was first coined by Mosier et al. in 2015, filling a conceptual gap in the management of airways in critically unwell patients.

• Critically unwell patients experience higher rates of peri-induction adverse events (one in five patients) irrespective of first pass intubation success, underscoring PDA as an additional entity to the traditional “anatomical” difficult airway.

• Hypoxaemia, hypotension, increased intracranial pressure, right ventricular failure, obesity and pregnancy present the most common and challenging PDA.

• Complications mostly occur during induction, intubation and transition to positive pressure ventilation.

• Environmental factors (ED, ICU, under-resourced ward) and human factors increase the risk of complications for PDAs

• Recent consensus statements published by Society of Critical Care Anaesthesiologists provide guidance on the management of PDAs

Preamble

You are an overnight anaesthesia registrar. You receive a call from a panicked ICU registrar requesting your assistance with an emergency intubation. The patient is a 60-year-old male admitted to ICU for severe community-acquired pneumonia, who has now deteriorated with respiratory fatigue, respiratory acidosis, and desaturation to 90%, despite an FiO₂ of 60% on non-invasive ventilation. Invasive blood pressure monitoring shows a mean arterial pressure of 67 mmHg and a sinus tachycardia of 110 bpm, supported by 2 mcg/min of noradrenaline. You attend to the patient immediately.

You confirm the patient’s previous airway grade as a Grade I with direct laryngoscopy. On examination, he has a thyromental distance of 7 cm, satisfactory mouth opening, and good neck extension. He is adequately fasted.

“Should be an easy airway, right?”

Tracheal intubation remains one of the most specialised and high-risk procedures performed in critical care, requiring the clinician to navigate the technical challenges of airway manipulation, rapid physiological alterations associated with apnoea, induction agents, and initiation of positive pressure ventilation—all within a matter of seconds.

Traditionally, an airway is anticipated to be “difficult” when there are anatomical features that impede the ability to ventilate and oxygenate the patient using bag-mask ventilation, tracheal intubation, or rescue supraglottic airway devices. These limitations prolong apnoea time and increase the risk of peri-intubation complications, including the “can’t intubate, can’t oxygenate” (CICO) scenario. The “anatomically difficult airway” is a well-recognised entity that has driven extensive advances in airway equipment, practice guidelines, and training for its management.

However, improvements in first-pass success rates have uncovered persistent peri-intubation complication rates in the critically ill. Indeed, observational studies have consistently demonstrated serious complication rates—such as hypoxaemia, haemodynamic instability, and cardiac arrest—to be around 20% in critically ill patients undergoing intubation, despite first-pass success. The International Observational Study to Understand the Impact and Best Practices of Airway Management in Critically Ill Patients (INTUBE) found that 45.2% of the 2,964 ICU patients undergoing intubation experienced at least one major adverse peri-intubation event. Specifically, while first-pass success was imperative in avoiding further critical desaturation (p<0.001 for both two attempts and >two attempts), it was not shown to be protective against haemodynamic instability (p=0.416 for first pass vs two attempts, and p=0.572 for >two attempts). As such, pathophysiological alterations not only pose peri-intubation challenges independent of traditional anatomical limitations, but they also exacerbate the negative consequences of a failed first-pass attempt in patients with compromised physiological reserve.

Mosier and colleagues first coined the term “physiologically difficult airway” (PDA) in 2015, recognising that pre-existing physiological derangements increase the rates of serious complications during intubation and the transition to positive pressure ventilation. The concept emphasises the need for critical care specialists to consider specific physiological derangements—beyond airway anatomy—when planning an intubation. Since then, growing recognition and research have improved the understanding and management of the PDA. In 2024, an international Delphi study chaired by the Society of Critical Care Anesthesiologists (SOCCA) Physiologically Difficult Airway Task Force synthesised the best available evidence and expert consensus into practice statements to guide the safe intubation of PDAs.

This article will explore the concept of the PDA, specific physiological derangements we commonly encounter, and key recommendations from the SOCCA Delphi study to aid our management of the critically ill airway.

What is a “Physiologically Difficult Airway (PDA)”

Mosier’s group and SOCCA define PDA as the patient who presents with pre-intubation physiological or pathophysiological factors that increase the risk of peri-intubation adverse events despite one or few intubation attempts, irrespective of (and possibly exaggerate) the effect of an anatomically difficult airway.

Multiple large observational studies have demonstrated pre-intubation haemodynamic compromise, defined as hypotension with mean arterial pressure (MAP) <65mmHg, systolic blood pressure <130mmHg, or sepsis, and requirement for pharmacological augmentation (e.g. need for vasopressor or fluid bolus, diuresis, or avoidance of propofol) to be associated with post-intubation hypotension. Similarly, pre-intubation respiratory failure requiring non-invasive ventilation, emergency or cardiac indication for intubation, and fluid resuscitation are all associated with post-intubation hypoxaemia. Unsurprisingly, age and advanced disease grades are patient factors that increase the risk of both hypotension and hypoxaemia.

Induction, apnoea, intubation and positive pressure ventilation impose drastic physiological changes and demands upon patients’ compensatory reserve, which is evidently diminished and largely exhausted in the critically ill. Hypotension and hypoxaemia commonly ensue due to inability to overcome the haemodynamic effects of anaesthetic agents, impaired oxygenation, hypermetabolic state, and unfavourable cardiopulmonary biomechanics of positive pressure ventilation. An understanding of specific physiological derangements and their effects on peri-intubation physiology is therefore paramount to mitigating these risks.

Understanding specific PDA scenarios

In their first description of PDA in 2015, Mosier and colleagues described 4 commonly encountered PDAs. This has since expanded to 6 in the SOCCA Delphi study. We summarise their pathophysiology, optimisation strategies and their associated evidence below:

Hypoxaemia

Failure to maintain adequate arterial oxygenation and resultant tissue hypoxia is one of the most common indications for intubation, and one that paradoxically carries the most significant risk of peri-intubation desaturation and worsening hypoxia, haemodynamic instability, hypoxic brain injury, and arrest.

Type 1 respiratory failure (hypoxaemic respiratory failure) results from gross ventilation-perfusion (V/Q) mismatch from pulmonary shunting (V/Q <1) where blood passes through alveolar units without adequately participating in gaseous exchange. Common causes include pneumonia, pulmonary oedema and acute respiratory distress syndrome. When intubating, type 1 respiratory failure patients are more prone to desaturation due to impaired gaseous exchange and limited response to pre-oxygenation. For the critically ill, an increased O2 demand may rapidly deplete an already compromised O2 reserve, while patients in physiological extremes such as severe obesity, pregnancy, paediatric and the elderly have diminished functional residual capacity (FRC) to maintain a sufficient O2 reservoir. However, severe Type 2 respiratory failure, particularly from obstructive airway disease, can present far greater challenges in ventilation and oxygenation. Managing these patients requires a delicate balance to mitigate the risks of under-ventilation, barotrauma and dynamic hyperinflation.

Optimisation strategies

The goal for these patients is to ensure optimal pre-oxygenation, appropriate airway assessment, intubation and ventilator setup, to prolong safe apnoea time (time between apnoea to critical desaturation), minimise total apnoea time, and maximise first-pass success rate.

Preoxygenation aims to denitrogenise a patient’s FRC with O2 and create an O2 reserve during apnoea. Standard method of pre-oxygenation using non-rebreather mask or bag-valve mask at maximal O2 flow is often inadequate for the critically ill, as their elevated respiratory rate limits tidal volume, impairs lung recruitment, and increases entrained ambient air which dilutes FiO2. Non-invasive ventilation (NIV) partly circumvents the problem by providing a tighter seal, positive end-expiratory pressure (PEEP) to improve lung recruitment, reduce shunting and improve oxygenation, and pressure support for additional tidal volumes. A randomised controlled trial by Baillard et al. showed patients undergoing intubation with hypoxaemic respiratory failure experienced less adverse events and desaturation <80% (17.8% vs. 41.3%) when pre-oxygenated with NIV compared to bag-valve mask. Pre-intubation anxiolytics and sedation may be required for patients with altered conscious states to improve compliance with NIV.

Once in the apnoeic phase post-induction, one may further prolong safe apnoea time with apnoeic oxygenation or positive mask ventilation. Apnoeic oxygenation involves the continued delivery of low-flow or high flow O2 during apnoea, entraining O2 down the lungs via the diffusion gradient generated by the patient’s alveolar O2 uptake. There is mixed evidence of its efficacy prolonging safe apnoea time and prevention of severe hypoxaemia.

While positive pressure mask ventilation post-induction has been traditionally discouraged (contraindicated in “classic” rapid sequence induction) due to concerns of gastric insufflation and aspiration, it has seen increased adoption by critical care specialists for safely managing critically ill, hypoxic patients with compromised FRC and O2 reserve. Real-time sonographic studies have demonstrated that mask ventilation pressures of less than 15cmH2O can safely improve ventilation without causing significant gastric insufflation. Recent randomised controlled trial investigating 400 intubations in US ICUs showed that mask ventilation not only reduced rates of severe hypoxaemia by 52%, aspiration events were not increased compared to the no-ventilation group. Both strategies can be considered to delay desaturation.

Ultimately, all steps should be taken to maximise first pass success as to minimise total apnoea time. Unsurprisingly, first pass failure requiring multiple attempts is directly related to increased rates of severe hypoxia and haemodynamic instability. Optimal patient positioning with 30 degrees head ramping, careful airway assessment, use of video laryngoscopy, and in cases of predicted “anatomical difficult airway”, use of intubation adjuncts (bougie/stylet), hyperangulated blade, and BURP, are all protocolised practices that are familiar for critical care physicians.

Hypotension

The critically ill patients often display hypotension as a late-stage sign of haemodynamic decompensation and shock. All four types of shock (distributive, hypovolaemic, obstructive, cardiogenic) are worsened to some degree by the venodilation, vasodilation and negative inotropic effects of anaesthetic agents and haemodynamic alterations from the transition to positive pressure ventilation. Unsurprisingly, post-intubation haemodynamic instability is by far the most common adverse event as illustrated by the INTUBE study.

Optimisation strategies

Appropriate pre-induction resuscitation, haemodynamic support with vasopressors, and use of “cardiostable” induction can assist to minimise/prevent peri-intubation cardiovascular collapse.

Volume resuscitation is a common first-line strategy for correcting hypotension, although careful assessment of patient fluid balance and volume tolerance is needed to avoid iatrogenic overload and cardiopulmonary decompensation. The multicentre randomised PrePARE and subsequent PrePARE II trial analysed the effectiveness of initiating a 500ml crystalloid bolus prior to induction for the critically ill and found no effect in reducing rates of cardiovascular collapse. As such, indiscriminate administration of fluid bolus is discouraged. Rather, individualised selection should be made through assessing fluid responsiveness (straight leg raise, pulse pressure variation (PPV), echocardiogram-evident inferior vena cava (IVC) collapsibility and left ventricular dynamic volume assessments) and balancing against risk of overload (through clinical and echocardiogram assessment, chest x-ray etc.)

Vasopressor support may be used to dampen the effects of induction agents and positive pressure ventilation to maintain perfusion pressure. Evidence is mixed around use of prophylactic vasopressor to prevent peri-induction cardiovascular collapse. Nevertheless, patients with distributive and cardiogenic shock are likely to benefit from the reduction in post-induction vasoplegia.

Appropriate choices of induction agents and their dosages are paramount to minimise haemodynamic instability during induction. Propofola nd thiopentone causes loss of vascular tone and bradycardia, leading to reduced preload, afterload and coronary perfusion pressure. These agents are therefore avoided in critically ill patients in favour of more “cardiac stable” agents such as etomidate, midazolam, ketamine, and fentanyl co-induction. There is ongoing debate regarding the superiority of either etomidate or ketamine in the critically ill in reducing cardiovascular instability. Regardless, one should judiciously dose-reduce based on patient factors and severity of illness, or employ an induction strategy to limit doses required of each agent to achieve sufficient anaesthesia.

Right heart failure

In addition to haemodynamic instability, Mosier specifically distinguished moderate-severe right ventricular (RV) dysfunction and failure as a PDA entity. Rightfully so, RV physiology is intimately related and exquisitely sensitive to the physiological alterations caused by anaesthetic induction and positive pressure ventilation.

In normal right heart circulation, the RV is a low pressure, high compliance, flow-based chamber that mobilises venous blood through the pulmonary vasculature. It is preload dependent, reliant on adequate venous return to generate Frank-Starling mediated contractility, and afterload sensitive, where marginal increases in pulmonary pressure in a low-pressure system can cause RV strain and trigger RV compensation. Long-standing pulmonary hypertension (from pulmonary vascular disease, left ventricular dysfunction, chronic airway disease, or chronic pulmonary embolism) leads to pathological RV remodelling, RV dysfunction, and ultimately RV failure, where the RV can no longer overcome excess afterload, resulting in retrograde flow, reduced left heart and coronary perfusion, and cardiovascular collapse.

Unfortunately, induction and positive pressure ventilation can impair RV compensatory mechanisms and add further RV strain

• Vasodilatory effects of induction agents reduce venous pressure and preload;

• Transient hypoxaemia and hypercapnia during apnoea results in pulmonary vasoconstriction and increase in pulmonary vascular resistance;

• Positive pressure ventilation increases intrathoracic pressure with a net effect of impeding venous return and increasing pulmonary vascular resistance, causing both reduced preload and increased RV afterload.

As such, intubating a patient with RV failure can result in RV decompensation and cardiovascular collapse.

Optimisation strategies

Optimisation of these patients requires a multidisciplinary approach and careful assessment. Common ventilatory aims would be to ensure adequate pre-oxygenation with sufficient etO2 using low PEEP NIV strategy, shorten apnoea time with apnoeic oxygenation to avoid hypoxaemia, and ventilate using spontaneous breathing modes to minimise positive pressure. Haemodynamics often needs to be evaluated using bedside echocardiograms to determine RV strain, contractile reserve and likelihood for fluid responsiveness. Use of fluid, vasopressors, and introduction of pulmonary vasodilators such as inhaled nitrous oxide should be guided by an expert team.

Intracranial hypertension

Intracranial pressure (ICP) is modelled by the Monro-Kellie doctrine. During cerebrovascular insults, such as intracranial haemorrhage, malignant ischaemic stroke, traumatic brain injury, and meningoencephalitis, intracranial pressure rises due to excess volume of blood and cerebral oedema within the rigid calvarium, resulting in compromised cerebral perfusion pressure and risk of herniation syndromes.

Laryngoscopy can cause a significant spike in ICP and worsen cerebral insult. Laryngoscopy may directly stimulate the gag/cough reflex in under-anaesthetised patients, in addition to the well-recognised sympathetic reflex that causes drastic spikes in heart rate, blood pressure and consequently raised ICP.

Optimisation strategies:

Key aims in the peri-intubation phase include pre-intubation optimisation, blunting of reflex sympathetic response to laryngoscopy, and post-intubation ventilation strategy.

In addition to standard preparation of pre-oxygenation and haemodynamic stabilisation, patient should be optimised to reduce ICP as much as possible

• Ventilate to etCO2 target that correlate with PaCO2 of 35-40 to limit cerebral vasodilation;

• Manage hypertension with short-acting beta-blockers and/or analgesia;

• Non-pharmacological management (head-up 30 degrees, minimise neck compression, hyperthermia avoidance) and pharmacological (hypertonic saline if clinical evidence of worsening ICP);

• Light sedation may be necessary to manage the agitated/non-compliant patient.

The neurocritical induction is heavily geared to blunting of the sympathetic reflex using large dose opioids. Fentanyl 3-5mcg/kg 1-3min prior to laryngoscopy is most commonly used in the emergent setting, while anaesthetists may have the luxury of accessing faster-onset and titratable opioids such as alfentanil and remifentanil.

Pharmacological strategies should not distract from non-pharmacological steps to minimise laryngoscopy manipulation:

• Maximise first pass success as previously discussed;

• Minimise force used with VL to achieve glottic exposure.

Once transitioned to positive pressure ventilation, neuroprotective ventilation strategy should be adopted:

• Avoid hypoxaemia

• Ventilate to PaCO2 30-35mmHg;

• Minimal PEEP to avoid ICP increases;

• Paralysis may be considered to further reduce ICP

Obesity & Pregnancy

Obesity and pregnancy have been specifically added by the SOCCA Delphi study as two PDAs. The predominant concern surrounds the restricted FRC, increased V/Q mismatch, and reduced O2 reserve due to increased metabolic demand, which limit the effectiveness of pre-oxygenation and make positive pressure ventilation particularly challenging. Haemodynamic effects of induction may be poorly tolerated from diminished compensatory reserve, or underlying cardiomyopathy. Lastly, the obese and parturient patients are at increased risk of aspiration during induction.

Optimisation strategies

While these patients present significant challenges in the peri-intubation setting, a structured approach using strategies outlined in “hypoxaemia” and “hypotension” can be similarly used to limit adverse events. Specifically, adequate pre-oxygenation, optimal patient positioning with ramping and a right wedge to prevent aortocaval compression, and careful haemodynamic monitoring with adequate resuscitation are important considerations.

Human factors in managing PDA

PDA adds additional cognitive and logistical challenges to an already complex procedure. Practitioners are often faced with high-acuity, time-sensitive and hyperdynamic scenarios in managing rapidly deteriorating patients, which can be overwhelming even for the most seasoned, leading to mistakes. Crisis resource management (CRM), which are non-technical skills that allow for optimal organisation and utilisation of available skillset, manpower and equipment in crisis situations, is paramount to enhance teamwork and performance.

Some key principles of CRM include clear role delegation appropriate for level of experience and training, closed loop communication, effective team leadership and shared mental model, all of which have been incorporated in airway management guidelines and simulation training.

The use of an “airway checklist” is common practice in ED and ICUs, providing a cognitive aid to ensure comprehensive patient, personnel, equipment and environmental preparation and minimise critical omissions prior to embarking on induction.

The team should at a minimum compose of a team leader who has overview of patient progress and provide clear decision-making, a primary airway operator, and an airway assistant/second airway operator. Clear verbalisation of airway and medication plan, including explicit checkpoints to enact contingency plans and seek early help, helps to establish a shared mental model of priorities and goals, catch complications early, and prevent task fixation and mobilise help to minimise further deteriorations.

Key SOCCA Statements

The following table summarises the key statements from the Delphi study on the approach to managing a PDA:

Team preparation

Use of airway checklists, Team assignment with at least 3 healthcare workers, Crisis resource management, including clear team roles, communication loops, shared mental model, cognitive aids etc., Simulation-based training.

Patient preparation and optimisation

Routinely perform airway assessment to anticipate difficult anatomical airway, Haemodynamic stabilisation with interventions such as vasopressor or inotrope infusion, Use of point-of-care ultrasound to assess and appropriately manage cardiac-related compromise, Use of non-invasive ventilation pre-oxygenation, apnoeic oxygenation, gentle positive pressure mask ventilation to avoid desaturation.

Performing the rapid sequence induction (RSI)

Use of the “head up” 30 degrees laryngoscopy position Use of a “modified” RSI with dose-adjusted rapid onset hypnotic (propofol, ketamine or etomidate), rapid-acting neuromuscular blocker (suxamethonium or rocuronium), judicious use of positive-pressure mask ventilation to optimise intubating conditions, Use of video laryngoscopy with bougie/stylet should be used routinely during the first attempt.

Post-intubation care

Immediate priorities include confirmation of tube placement (consistent etCO2 pattern over 7 breaths) and management of complications, most commonly cardiovascular instability and hypoxaemia, Use of lung protective ventilation, using Tidal volumes 6-8ml/kg of predicted body weight (PBW) PEEP >= 5 cmH2O Plateau pressure <30 cmH2O FiO2 titrated to SpO2 aims 92-95% Invasive blood pressure monitoring, central venous access to manage persistent haemodynamic instability post-intubation.

Conclusion

Despite the patient having no red flags for difficult laryngoscopy, you recognise the patient has a physiologically difficult airway. Together with your ICU colleagues, you set out to maximise preparations to optimise your attempt

• You organised your team with the ICU reg as the team leader, yourself as the primary airway operator, and the nurse-in-charge as the airway assistant, with the resident performing drug administration.

• Your team contacts your respective consultant-on-call to be readily available to assist if the patient deteriorates.

• You verbalise your plan to the team, with plan A being ETT size 8 with size 4 VL with bougie +/- BURP (max 2 attempts), plan B for second generation size 4 LMA + consultant assistance, with plan C to revert to BMV if plan B fails or saturation <88% at any stage and consider plan D – front of neck access.

• During this time, you positioned the patient to head up 30 degrees, pre-oxygenate the patient with NIV on 100% FiO2 for 5 min and provided a 500ml crystalloid bolus which increased the patient’s MAP to 72mmHg.

• You opted to give a cardiac-stable modified RSI of 1mg/kg ketamine, 2mg midazolam and 1.2mg/kg rocuronium, with gentle positive mask ventilation post induction.

Thankfully, your first pass was successful. The patient’s saturation decreased to 95%, blood pressure was relatively stable on 5mcg/min norad.

While advances in training, guidelines and airway technologies have increased our competencies in managing the anatomically difficult airways, the PDA has only gained recognition over the last decade, unveiling the multidimensional complexities in its management. This recent Dephi study by SOCCA provides guidance on best practice of managing PDAs, and provides a robust foundation for ongoing research regarding their feasibility in clinical practice.

References

Al-Saadi, M. A., Heidari, B., Donahue, K. R., Shipman, E. M., Kinariwala, K. N., & Masud, F. N. (2023). Pre-Existing Right Ventricular Dysfunction as an Independent Risk Factor for Post Intubation Cardiac Arrest and Hemodynamic Instability in Critically Ill Patients: A Retrospective Observational Study. Journal of intensive care medicine, 38(2), 169–178. https://doi.org/10.1177/08850666221111776

Baillard, C., Prat, G., Jung, B., Futier, E., Lefrant, J. Y., Vincent, F., Hamdi, A., Vicaut, E., & Jaber, S. (2018). Effect of preoxygenation using non-invasive ventilation before intubation on subsequent organ failures in hypoxaemic patients: a randomised clinical trial. British journal of anaesthesia, 120(2), 361–367. https://doi.org/10.1016/j.bja.2017.11.067

Bouvet, L., Albert, M. L., Augris, C., Boselli, E., Ecochard, R., Rabilloud, M., Chassard, D., & Allaouchiche, B. (2014). Real-time detection of gastric insufflation related to facemask pressure-controlled ventilation using ultrasonography of the antrum and epigastric auscultation in nonparalyzed patients: a prospective, randomized, double-blind study. Anesthesiology, 120(2), 326–334. https://doi.org/10.1097/ALN.0000000000000094

Casey, J. D., Janz, D. R., Russell, D. W., Vonderhaar, D. J., Joffe, A. M., Dischert, K. M., Brown, R. M., Zouk, A. N., Gulati, S., Heideman, B. E., Lester, M. G., Toporek, A. H., Bentov, I., Self, W. H., Rice, T. W., Semler, M. W., & PreVent Investigators and the Pragmatic Critical Care Research Group (2019). Bag-Mask Ventilation during Tracheal Intubation of Critically Ill Adults. The New England journal of medicine, 380(9), 811–821. https://doi.org/10.1056/NEJMoa1812405

Karamchandani, K., Nasa, P., Jarzebowski, M., Brewster, D. J., De Jong, A., Bauer, P. R., Berkow, L., Brown, C. A., 3rd, Cabrini, L., Casey, J., Cook, T., Divatia, J. V., Duggan, L. V., Ellard, L., Ergan, B., Jonsson Fagerlund, M., Gatward, J., Greif, R., Higgs, A., Jaber, S., … Society of Critical Care Anesthesiologists (SOCCA) Physiologically Difficult Airway Task Force (2024). Tracheal intubation in critically ill adults with a physiologically difficult airway. An international Delphi study. Intensive care medicine, 50(10), 1563–1579. https://doi.org/10.1007/s00134-024-07578-2

Mosier, J. M., Joshi, R., Hypes, C., Pacheco, G., Valenzuela, T., & Sakles, J. C. (2015). The Physiologically Difficult Airway. The western journal of emergency medicine, 16(7), 1109–1117. https://doi.org/10.5811/westjem.2015.8.27467

Mosier, J. (2024). The Physiologically Difficult Airway and Management Considerations. Curr Anesthesiol Rep 14, 446–457 . https://doi.org/10.1007/s40140-024-00629-w

Myatra, S. N., Divatia, J. V., & Brewster, D. J. (2022). The physiologically difficult airway: an emerging concept. Current opinion in anaesthesiology, 35(2), 115–121. https://doi.org/10.1097/ACO.0000000000001102

Nickson, C. (2023). Intubation of the Neurocritical Care Patient. Life In the Fast Lane.URL: https://litfl.com/intubation-of-the-neurocritical-care-patient/, [Last accessed 25/11/2024]

Patel, S. D., & Habib, A. S. (2021). Anaesthesia for the parturient with obesity. BJA education, 21(5), 180–186. https://doi.org/10.1016/j.bjae.2020.12.007

Russell, D. W., Casey, J. D., Gibbs, K. W., Ghamande, S., Dargin, J. M., Vonderhaar, D. J., … & Whitson, M. R. (2022). Effect of fluid bolus administration on cardiovascular collapse among critically ill patients undergoing tracheal intubation: a randomized clinical trial. Jama, 328(3), 270-279.

Russotto, V., Myatra, S. N., Laffey, J. G., Tassistro, E., Antolini, L., Bauer, P., … & Giacomucci, A. (2021). Intubation practices and adverse peri-intubation events in critically ill patients from 29 countries. Jama, 325(12), 1164-1172.

White, L. D., Vlok, R. A., Thang, C. Y., Tian, D. H., & Melhuish, T. M. (2023). Oxygenation during the apnoeic phase preceding intubation in adults in prehospital, emergency department, intensive care and operating theatre environments. Cochrane Database of Systematic Reviews, (8).

Most anaesthetists probably remember the first time they heard the ‘death spiral’. This is a colloquial term used for the lowering pitch of the pulse oximeter tone as the oxygen levels fall. Once learnt, it becomes an unforgettable and daily part of your anaesthesia practice.

I was thinking about all the non visual cues that I’ve learnt over the years and realised that many of these are not obvious and often take time to learn.

If you only rely on what you see, you may miss a great deal of what is happening and react slowly to an unfolding crisis. After all, your eyes can only focus on a small area at any one time, whereas your ears are able to take in all the sounds in your vicinity. With time, you’ll find that you can rapidly react to an unfolding issue even before you see it.

Here are a few of the non visual cues that are of critical importance.

The surgeon

Each surgeon has a certain style, whether it’s surgical technique, manner, speech etc. One thing that becomes very obvious is the change in voice when something is not going well.

They may talk louder, faster, more abruptly, with more profanity or even become deathly quiet. These are cues that you need to pay closer attention to the patient, surgeon and your monitor and perhaps ask directly if everything is okay.

The suction

This little device sounds like a constant hum in the background during surgery. As it is used for suction of fluids (i.e. blood) it is critically important that you pay close attention to this sound. It signal the start of catastrophic blood loss and the need for rapid replacement of blood products and cardiovascular support.

During caesarean section, the loud suctioning of amniotic fluid signals surgical entry into the uterus and is an indicator that the baby is being delivered. At this point you need to consider uterotonic administration (oxytocin).

The pulse oximeter or ‘sats probe’

This amazing device conveys much valuable information. Each sensed pulse produces an audible tone. This tone changes in pitch if the oxygen saturation changes. For example, if the oxygen levels fall from 99% to 90%, the tone will drop in pitch as the saturations fall. This is an incredibly useful signal to notify the anaesthetist that the oxygen levels are falling even when they are performing another task.

The pulse oximeter tone also gives an indication of heart rate (as does the ECG and arterial line).

Your ability to rapidly detect a sudden bradycardia could mean the difference between treating a heart rate of 20 or asystole.

Likewise imagine a sudden rise in heart rate. The patient may be too ‘light’ or require analgesia. The difference in detecting this quickly may mean preventing awareness or the patient moving suddenly.

Monitor alarms

This is the most obvious non visual cue. I won’t say too much except that there is an incredible amount of research that has gone into ensuring how alarms are programmed. They are of a certain pitch, volume and frequency to ensure they are the optimal balance of a few things. They must notify the clinician, but not contribute to excess noise pollution or lead to habituation.

It is vital that as a anaesthetist you are comfortable setting the thresholds for your alarms that are appropriate to each patient. For example, if the default blood pressure alarm activates at 80mmHg, this could be unsafe for a hypertensive patient with severe aortic stenosis who needs a higher coronary perfusion pressure. Reprogram each alarm that is crucial for your particular patient.

If there are any other nom visual cues that you find useful, please post or comment below!

It seems that regional anaesthesia is somewhat past its heyday. 

Many hospitals have adopted other techniques for pain management in operations that were once common practice grounds for regional, hospitals don’t have the systems set up to facilitate fast turnover and having sufficient time for regional anaesthesia onset and there are no studies to prove convincingly any long term morbidity or mortality benefit. 

However in my experience this is one of the most incredibly useful skills in your anaesthesia quiver!

There will be many times in your career that you will be required to anaesthetise an incredibly sick patient for a peripheral/limb procedure. 

Imagine a patient from ICU requiring an urgent open reduction and fixation of his fractured ankle. He is 150kg, on BIPAP for pneumonia, heart failure with EF30% and saturating at 90% due to his severe COPD. Performing a general anaesthetic for this operation is definitely an option and will require a lot of prep time and may result in airway management difficulty, CVS instability and oxygenation risks. And this situation isn’t that uncommon! It will arise time and time again whether it’s an upper limb procedure, lower limb procedure or the elective arterio-venous fistula in a sick renal patient. 

I would argue your ability to perform effective regional anaesthesia improves welfare for the patient and ease of providing effective anaesthesia for you and your team!

So with fewer opportunities to provide regional anaesthesia how do you gain enough experience? If practice makes perfect how do you get enough practice?

It is vital to manufacture practice and create opportunities!

What do I mean? Well there are a few select skills with ultrasound (US) guided regional anaesthesia that you can master even with minimal practice at actual regional anaesthesia. ‘Chunking’ these skills and practising them separately is one of the best ways to learn difficult and uncommon techniques

These skills are:

1. US scanner competence
2. Sono-anatomy mastery
3. US-Needle coordination

US scanner competence

• Bring out the US scanner at every opportunity to scan nerves, veins, arteries and hearts
• Learn a systematic way of improving your image. 
  • Select the correct probe
  • Select the depth
  • Optimise the gain (how much signal or ‘whiteness’ comes back)
  • Select the focal point
  • Probe manipulation: practice sliding, tilting, rotating and translating

Sono-anatomy mastery

Sono-anatomy is like exploring a new neighbourhood. The first few times everything is unfamiliar and you won’t recognise much. You then decide to buy a map and explore your new neighbourhood every day and suddenly you will start to recognise signs, roads, laneways and your favourite cafes and shops. 

The way I increased my familiarity with the sonoanatomy neighbourhood was to scan a patient every day. My map was Ultrasound Imaging for Regional Anaesthesia from www.usra.ca/education/booklet.php (electronic copy available on iTunes). This is an exceptional resource, which shows the labelled cadaveric and sono-anatomy so you can trace the nerves from proximal to distal in the upper and lower limb. 

Put a probe on the consented patient and try the following. For your lower body cases try tracing the brachial plexus from the interscalene, to supraclavicular, infraclavicular and axillary views and then trace the terminal nerves (ulnar, median and radial) from axilla to the wrist. Likewise during your upper body cases you can ‘walk’ around the lower limb sono-anatomy neighbourhood tracing the femoral nerve and sciatic nerves. Use Ultrasound Imaging for Regional Anaesthesia to show you the relevant structures.  

After doing this a few times you will gain familiarity of the  

• nerve plexuses
• nearby structures, 
• the way nerves often follow vascular structures and
• the way they differ from tendons and muscles.
• With even more experience you will notice the inter-patient variability and abnormal anatomy. This becomes increasingly relevant when you notice that some patients are difficult to block because they have aberrant nerves, tissue/septae that divide plexuses or vascular structures running nearby.

Another great way to have guided practice is to sign up to one of the many US regional anesthesia short courses. 

Other useful resources include:

• www.nysora.com
• www.asra.com
• AnSo app

US needle coordination

There are many techniques that are common in anaesthesia and enable us to practice US needle coordination. After you have mastered cannulation try performing cannulation with US guidance. This is a great way to improve your success with difficult cannulation but also a great way to learn how to coordinate your needle manipulation in one hand and the US probe in the other. 

Other slightly advanced techniques to improve US coordination are US guided arterial line insertion and central line insertion.

In my experience there were some relatively common opportunities for US guided regional anaesthesia. The fascia iliaca blockand femoral nerve blockare considered relatively safe and easy techniques and where I developed most of my skills in US coordination. They are superficial, the landmarks are easy to find, have few critical structues and inadvertent vascular puncture can be compressed to stop a haematoma. When clinically indicated, do these regional blocks with US guidance.

So there is it! My method for trying to increase your learning curve, when your learning opportunities might be few and far between.

Any questions or comments please email me 

Anaesthesiacollective@gmail.com

https://riskcalculator.facs.org is an exceptional resource to provide reasonably accurate and patient specific risk information to help guide your perioperative decision making.

This calculator uses a series of 20 questions and the surgical procedure to provide 18 different outcomes within 30 days of the procedure. These include risk of death, serious complications and even the chance of whether the patient will need postoperative rehab.

Before this calculator existed I felt that I had a lack of insight into the risks outside of the intra-operative anaesthesia risk. As anaesthetists, we rarely follow up our patients and may not be aware of the patient’s risk a month after the operation. Even our surgical colleagues may not have great data on their patient’s risk profile on such a large scale.

This calculator was built using data from over ‘4.3 million operations in over 730 participating hospitals from 2013-2017‘

I find the calculator most useful when I have a particularly unwell patient. I am able to quickly plug in the requested data points and then assess the risk. Have a look at the risk profile below for this imaginary elderly male undergoing a laparoscopic cholecystectomy.

I find this incredibly useful information to guide my perioperative management and providing informed consent to the patient.

For example I may

• refer to HDU/ICU preop
• discuss risk factor modification and use it as a ‘teachable moment’
• use the data to highlight how high risk (or low risk) something might be to a patient or colleague who has a different opinion on the risk level
• plan post op nursing or rehab requirements
• choose to recommend a particular operation in a centre with ICU/cardiology support
• discuss the risks and benefits with more evidence than limited by my own experience

any questions please comment below!

I was recently supervising an exceptional trainee. He did everything right to make the most from our operative list together. He texted me the night before with things he wanted to learn, He arrived early to the list and had everything checked and set up. I was really impressed with his motivation and assertiveness and knew he would have a rapid learning curve. Now as it happened he also missed an intravenous cannula and wasn’t able to insert the spinal needle. What was really interesting was that this was quite upsetting for my trainee but my impression was that he was very competent and reliable doctor in training.

My assessment of his ability and his assessment of his ability were worlds apart!

I now think back to my own training, and how important it seemed that we are always ‘successful’. We are praised for success and often berated if we don’t succeed, even though many of our technical tasks as anaesthetists can be very humbling.

While we do improve over time, there will be some veins that we just fail to access, arterial lines that never seem to thread and spinals where we just aren’t able to find a route into that elusive intrathecal space.

But what I suggested to my trainee is that the path to success isn’t repeated success…

The path to success is a diligent process of repeated failure

I could now write a whole bunch of cliches or post some inspirational memes proving my point but you’ve probably already seen these, but one does stick to mind… you would never think an infant failed as they stumbled trying to walk. It is simply the process that gets us to a point of competence.

I hope that most of us (trainees and supervisors) realise the critical important of rewarding a diligent process and showing very little if any frustration or negativity if the initial outcome isn’t success.

I believe that this would foster a more productive culture for learning, development and welfare.