Anaesthesia and Perioperative Assessment

Anaesthesia — Anaesthesia and Perioperative Care, NMC MBBS licence examination syllabus (Nepal Medical Council).

Anaesthesia and perioperative care

Most of what determines a safe operation happens before the patient reaches theatre.

Anaesthesia looks like a technical specialty, and the technical parts are indeed specialist. But the parts a newly qualified doctor is responsible for are not technical at all: assessing whether a patient can withstand the planned procedure, optimising what can be optimised, taking a proper drug history, and recognising a small number of emergencies.

Those tasks are unglamorous and they matter enormously. A patient who arrives in theatre anaemic, with uncontrolled diabetes, or with their long-term steroid omitted, has been put at avoidable risk before the anaesthetist has done anything.

🩺 Where this lives: The single most consequential thing a junior doctor does in perioperative care is take the drug history properly. A long-term steroid omitted on the drug chart can produce an adrenal crisis on the table. An anticoagulant continued without a plan causes uncontrolled bleeding; stopped without a plan causes a thrombotic event. Antiepileptics missed for two days cause seizures. None of these requires specialist knowledge to prevent — only the discipline of asking what the patient actually takes, including inhalers, injections and anything bought without a prescription.

💡 A note on doses. This chapter contains no doses at all, and specifically no local anaesthetic maximum doses, no adrenaline doses and no fasting times. Local anaesthetic maxima are weight-based and agent-specific, adrenaline dosing differs by route and age, and fasting guidance has been revised — each can kill if wrong. It also gives no airway grading systems, since several exist, none predicts reliably, and what matters is having a plan B. Postoperative complications are in the Wounds chapter, analgesia in Analgesics, fluids in the Fluids chapter, and steroid cover in the Adrenal chapter.

The preoperative assessment

The most informative question in the entire assessment is about functional capacity: what can this person actually do? Someone who climbs two flights of stairs without stopping has demonstrated cardiorespiratory reserve more convincingly than most investigations could. Someone breathless walking to the toilet has demonstrated the opposite. This costs nothing, requires no equipment, and predicts perioperative risk better than a resting ECG in a patient with no symptoms.

WHAT TO ACTUALLY ASK AND CHECK THE HISTORY Exercise tolerance in concrete terms — stairs, distance, hills, carrying things Cardiac and respiratory symptoms, and how well controlled Diabetes, and how well controlled Previous anaesthetics — and any PROBLEM with them FAMILY history of anaesthetic problems (see malignant hyperthermia below) Reflux, obstruction, pregnancy — anything raising aspiration risk Smoking and alcohol ALLERGIES — and what actually happened, since "allergy" often means intolerance (see the prescribing safety chapter) EVERY DRUG, including inhaled, topical, injected and over-the-counter preparations THE EXAMINATION Cardiovascular and respiratory · the AIRWAY · dentition, including loose or capped teeth · site marking and consent WHAT IS WORTH OPTIMISING BEFORE ELECTIVE SURGERY ANAEMIA — treat the cause where possible; transfusing on the day of surgery is a poor substitute for iron given weeks earlier Uncontrolled diabetes, hypertension, asthma or heart failure Untreated infection Smoking cessation, even briefly, improves outcomes INVESTIGATIONS ARE GUIDED BY THE PATIENT AND THE PROCEDURE, not ordered as a routine panel. A test that will not change management adds delay and false positives.

The airway

💡 Exam angle: the examinable principle is that no single bedside test reliably predicts a difficult airway — which is exactly why assessment is combined with preparation. Features worth noting are limited mouth opening, restricted neck movement, a receding jaw, obesity, neck swelling or scarring, advanced pregnancy, and any previous difficult intubation. The scenario every plan exists for is "cannot intubate, cannot oxygenate", and the answer to it is a rehearsed sequence rather than improvisation.

Fasting and aspiration

Fasting exists for one reason: anaesthesia abolishes the airway reflexes, so gastric contents can enter the lungs. The groups at higher risk are worth knowing — emergency surgery, pregnancy, bowel obstruction or ileus, reflux, obesity and diabetic gastroparesis. Note the balance, though: an unfasted patient needing life-saving surgery is not left to deteriorate. The anaesthetic technique is adapted instead. And prolonged unnecessary starvation is itself harmful, particularly in children, the elderly and diabetic patients.

Medication before surgery

THE DECISIONS THAT MATTER MOST STEROIDS — CONTINUE, AND USUALLY INCREASE Surgery is one of the major physiological stresses. A patient on long-term steroids cannot mount their own cortisol response, so omitting the dose risks an ADRENAL CRISIS intraoperatively or afterwards. This is covered in the adrenal chapter, and it is among the commonest avoidable perioperative catastrophes. ANTICOAGULANTS AND ANTIPLATELETS — DECIDE, DO NOT DRIFT Continuing risks bleeding; stopping risks thrombosis, stroke or stent occlusion. The decision balances the bleeding risk of the operation against the reason the drug was prescribed, and it belongs to the surgical and anaesthetic teams together — not to whoever happens to be clerking. DIABETES DRUGS — need a plan for the fasting period, with glucose monitoring. Both hypoglycaemia and uncontrolled hyperglycaemia cause harm. USUALLY CONTINUED: most cardiac and respiratory medication, ANTIEPILEPTICS (missed doses cause seizures), thyroid replacement, and Parkinson's medication, where even short interruptions matter. AND THINK ABOUT THROMBOPROPHYLAXIS — surgery, immobility and malignancy together create high venous thromboembolism risk. Assess every surgical patient, as noted in the wounds chapter. All specific timings and regimens follow national guidance.

Anaesthetic emergencies

💡 Exam angle: three are worth recognising by pattern. Anaphylaxis — sudden hypotension with bronchospasm and swelling; adrenaline early, and it is the treatment rather than an adjunct. Malignant hyperthermia — a rising end-tidal carbon dioxide with rigidity and tachycardia, fever appearing later; it is inherited, which is why the family anaesthetic history is asked beforehand. And local anaesthetic toxicity — perioral tingling and tinnitus progressing to confusion, seizures and arrhythmia, which is why you aspirate before injecting and stay within the maximum dose for that agent and weight.

Clinical reasoning: four presentations

🔍 Case 1 — the steroid nobody wrote up

PresentationA woman on long-term prednisolone for a rheumatological condition is admitted for surgery. Her regular steroid is not transcribed onto the inpatient chart. Intraoperatively she becomes profoundly hypotensive, unresponsive to fluid and vasopressors.

CauseAdrenal crisis from an omitted steroid.

ReasoningLong-term steroids suppress the adrenal axis. Surgery is a major stress requiring an increased cortisol response that she cannot generate, and the dose was omitted rather than increased.

AnswerGive steroid immediately — see the adrenal chapter. Prevention is a properly taken drug history and steroid cover per guidance; this is among the commonest avoidable perioperative catastrophes.

🔍 Case 2 — fit enough on paper

PresentationA 68-year-old is listed for major elective surgery. His resting ECG and chest X-ray are normal, so he is deemed fit. Asked directly, he says he becomes breathless walking to the end of his lane and sleeps in a chair.

Missed informationFunctional capacity.

ReasoningResting investigations in an asymptomatic-seeming patient tell you little. Breathlessness on minimal exertion with orthopnoea suggests significant cardiorespiratory limitation and possible heart failure.

AnswerAssess and optimise before elective surgery — investigate the breathlessness, treat what is treatable, and discuss risk honestly with the patient and surgical team.

🔍 Case 3 — anticoagulated and drifting

PresentationA man on long-term anticoagulation for atrial fibrillation is admitted for elective surgery. Nobody makes a decision about it; the drug is simply not written up on admission and nothing further is said.

ProblemA decision made by default.

ReasoningStopping anticoagulation without a plan exposes him to stroke; continuing without a plan exposes him to bleeding. Either may be right — but it must be a considered decision with a documented plan for stopping and restarting.

AnswerEscalate to the surgical and anaesthetic teams for an explicit decision per national guidance, balancing procedural bleeding risk against his thrombotic risk, and document the plan.

🔍 Case 4 — tingling lips during a block

PresentationDuring infiltration of local anaesthetic for a minor procedure, the patient reports tingling around the mouth and ringing in the ears, then becomes confused. Injection continues while the operator finishes.

DiagnosisLocal anaesthetic systemic toxicity.

ReasoningPerioral tingling and tinnitus are early features, progressing to confusion, seizures and cardiac arrhythmia. Continuing to inject worsens it.

AnswerStop injecting immediately, call for help, support the airway and circulation, and manage per local protocol. Prevention: aspirate before injecting, inject slowly, and stay within the maximum dose for that agent and the patient's weight.

Commonly confused

Confusion	The distinction	Why it matters
Normal resting tests vs fitness	Functional capacity predicts better	Ask what they can actually do.
Routine panel vs targeted tests	Guided by patient and procedure	Tests that change nothing add delay.
Omitting vs increasing steroids	Surgery increases requirement	Omission risks adrenal crisis.
Stopping anticoagulation by default vs deciding	Both directions carry risk	It must be an explicit documented plan.
Fasting vs prolonged starvation	Unnecessary starvation is harmful	Especially in children and the elderly.
Unfasted vs cannot operate	The technique is adapted	Life-saving surgery is not delayed.
Predicting vs preparing for a difficult airway	No test predicts reliably	Always have a plan B.
Early LA toxicity vs anxiety	Perioral tingling and tinnitus	Stop injecting immediately.

Rapid revision

MUST-KNOW FACTS 1. Preoperative assessment asks: can they tolerate it, can anything be optimised, what about airway and drugs? 2. FUNCTIONAL CAPACITY predicts risk better than most investigations. 3. "Can you climb two flights of stairs without stopping?" 4. Ask about PREVIOUS anaesthetics and any problems. 5. Ask about FAMILY anaesthetic history — malignant hyperthermia is inherited. 6. Ask about ALLERGIES and what actually happened. 7. Record EVERY drug, including inhaled, topical and over-the-counter. 8. Optimise ANAEMIA, diabetes, hypertension, asthma, heart failure, infection. 9. Investigations are guided by patient and procedure, not routine. 10. No single test reliably predicts a DIFFICULT AIRWAY. 11. Features: limited mouth opening, restricted NECK movement, receding jaw, obesity. 12. Also neck swelling or scarring, pregnancy, previous difficulty. 13. ALWAYS HAVE A PLAN B — "cannot intubate, cannot oxygenate". 14. Fasting exists because anaesthesia ABOLISHES AIRWAY REFLEXES. 15. Aspiration risk: EMERGENCY surgery, PREGNANCY, obstruction, reflux, obesity. 16. An unfasted emergency patient is not left to deteriorate — technique is adapted. 17. PROLONGED STARVATION IS ITSELF HARMFUL. 18. STEROIDS ARE CONTINUED AND USUALLY INCREASED — never omitted. 19. Omitting them risks ADRENAL CRISIS. 20. ANTICOAGULANTS need an explicit DECISION, not a default. 21. Balance procedural bleeding risk against the reason for the drug. 22. Diabetes medication needs a fasting plan with glucose monitoring. 23. Usually continued: cardiac, respiratory, ANTIEPILEPTICS, thyroid, Parkinson's. 24. Assess THROMBOPROPHYLAXIS in every surgical patient. 25. ANAPHYLAXIS: sudden hypotension, bronchospasm, swelling — ADRENALINE early. 26. MALIGNANT HYPERTHERMIA: rising end-tidal CO2, rigidity, tachycardia, then fever. 27. It is INHERITED — ask the family history beforehand. 28. LOCAL ANAESTHETIC TOXICITY: perioral tingling, tinnitus, confusion, seizures. 29. STOP INJECTING immediately and call for help. 30. Aspirate before injecting and stay within the maximum dose. 31. Take all doses, fasting times and timings from national guidance.

💡 Exam angle: two threads recur. The drug history — steroids continued, anticoagulation decided rather than defaulted, antiepileptics never missed. And the recognition of the three anaesthetic emergencies by their opening pattern, each of which requires stopping something and calling for help before anything else.

Syllabus points

The three preoperative questions
Why functional capacity predicts risk
What to ask in the history
What to optimise before elective surgery
Targeted rather than routine investigation
Predicting a difficult airway
Why there is always a plan B
Why patients are fasted
Higher aspiration risk groups
Why prolonged starvation is harmful
Steroids continued and increased
Anticoagulation as an explicit decision
Anaphylaxis and malignant hyperthermia
Local anaesthetic toxicity

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