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NEET PG Anesthesia★ Airway management contributes 5-7 NEET PG questions per attempt, with difficult airway prediction, rapid sequence induction, suxamethonium contraindications, capnography and cricothyroidotomy appearing every year

"Airway Management & Difficult Airway"

"Airway management has one governing principle: oxygenation, not intubation, is the goal. Patients die from failure to oxygenate rather than from failure to place a tube, which is why every difficult airway algorithm is a sequence for maintaining oxygen while attempts continue."

⏱ 22 min readHard difficulty✓ Free · exam-pattern aligned

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Timed practiceMCQs from this chapter with instant scoring

FlashcardsFormulas & traps on spaced repetition

NEET PG PYQsSolved previous-year questions

By the end of this chapter you'll be able to…

1State why oxygenation rather than intubation is the governing goal
2Explain why repeated laryngoscopy attempts cause harm
3Apply the bedside predictors of difficult intubation and state their limitations
4Perform and interpret the Mallampati assessment correctly
5List the predictors of difficult mask ventilation separately from intubation
6Recognise conditions that raise airway risk, including oral submucous fibrosis
7Explain the physiology of preoxygenation and denitrogenation
8Explain why children, pregnant and obese patients desaturate rapidly
9Sequence airway management from basic manoeuvres to definitive airway
10State the limitation of supraglottic airway devices
11Justify waveform capnography as the standard for confirming placement
12Manage the can't intubate can't oxygenate situation
13State the anatomical basis of cricothyroidotomy and its paediatric contraindication
14Justify awake intubation in the anticipated difficult airway
15State the benefits and characteristic pitfall of videolaryngoscopy
16Describe rapid sequence induction and its components
17List the adverse effects and contraindications of suxamethonium
18Explain the mechanism and timing of suxamethonium-induced hyperkalaemia
19State the current position on cricoid pressure
20Apply fasting guidelines and identify patients who are never considered fasted
21Plan extubation and manage laryngospasm
22State the anatomical and physiological differences of the paediatric airway

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Why this chapter matters in NEET PG

Airway management is often taught as a set of techniques and a list of predictors, which obscures the principle that determines whether a patient survives: oxygenation is the goal, and intubation is only one way of achieving it. Patients do not die because a tube could not be placed; they die because oxygen delivery stopped while attempts continued. Two consequences follow. Repeated laryngoscopy causes bleeding and oedema that convert a difficult airway into an impossible one, so attempts are capped deliberately. And because no bedside test predicts difficulty reliably, the correct response is not better prediction but better preparation, with a stated plan A, B and C before every induction.

Before you start — revise these

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Anatomy

Upper airway anatomy, the cricothyroid membrane, laryngeal structures and the paediatric airway differences underlie every technique in this chapter.

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Physiology

Functional residual capacity, oxygen consumption, denitrogenation and the physiology of apnoea determine safe apnoea time and preoxygenation strategy.

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General Anesthesia Drugs & Protocols

Induction agents, neuromuscular blockers and reversal agents are developed there and are assumed in the rapid sequence induction section.

Airway Management & Difficult Airway

Airway management is often taught as a set of techniques and a list of predictors, which obscures the principle that determines whether a patient survives.

Oxygenation is the goal. Intubation is only one way of achieving it.

Patients do not die because a tracheal tube could not be placed. They die because oxygen delivery stopped while attempts continued. Every difficult airway algorithm is therefore a structured sequence for maintaining oxygenation while limiting the number of attempts.

A second principle follows directly. Repeated attempts cause the harm. Each laryngoscopy traumatises tissue, produces bleeding and oedema, and converts an airway that could be ventilated by mask into one that cannot.

A third principle governs preparation. The airway assessment predicts poorly, so plan for failure in every case. No bedside test has both good sensitivity and good specificity, which means the sensible response is not better prediction but better preparation.

1. Predicting Difficulty

Several tests are used, and each has modest performance alone.

Mallampati classification grades the view of pharyngeal structures with the mouth open and tongue protruded, from class I where soft palate, fauces, uvula and pillars are visible, to class IV where only the hard palate is seen. It is performed with the patient sitting and without phonation, since phonating raises the palate and falsely improves the grade.

Thyromental distance below about 6 cm suggests limited space for displacing the tongue during laryngoscopy.

Mouth opening below about 3 cm limits instrumentation directly.

Neck extension matters because the classical laryngoscopy position aligns the oral, pharyngeal and laryngeal axes, and limited extension prevents that alignment.

Previous difficult intubation is the single most useful predictor, which is why it is asked about first and why documented difficulty must be recorded and communicated.

Specific conditions raise risk substantially: obesity, pregnancy, obstructive sleep apnoea, rheumatoid arthritis with atlantoaxial involvement, ankylosing spondylitis, acromegaly, and post-radiotherapy or post-burn neck contracture.

Oral submucous fibrosis deserves separate mention in Indian practice, because progressive trismus from areca nut use limits mouth opening severely and is frequently not volunteered by the patient.

2. Preoxygenation

Preoxygenation buys the time within which everything else happens, and it is the step most often performed inadequately.

The principle is denitrogenation. Breathing 100 per cent oxygen replaces the nitrogen in the functional residual capacity with oxygen, creating a reservoir that sustains saturation during apnoea.

Adequate preoxygenation extends safe apnoea time from around one minute to several minutes in a healthy adult.

Three groups desaturate far faster and are the ones in whom preoxygenation matters most. Children, because they consume oxygen at roughly twice the adult rate per kilogram with a proportionally smaller functional residual capacity. Pregnant women, because the gravid uterus reduces functional residual capacity while oxygen consumption rises. And obese patients, for the same mechanical reason.

Head-up positioning improves preoxygenation in obese and pregnant patients by increasing functional residual capacity.

3. Managing the Airway Stepwise

The sequence moves from least to most invasive, and each step buys time for the next.

Basic manoeuvres open the airway by lifting the tongue off the posterior pharyngeal wall: head tilt with chin lift, or jaw thrust where cervical spine injury is possible.

Airway adjuncts hold that position. An oropharyngeal airway is not tolerated in a patient with an intact gag reflex, whereas a nasopharyngeal airway is, which makes the latter useful in the semiconscious patient.

Bag-mask ventilation is the skill that saves lives and is more important than intubation, because a patient who can be ventilated by mask has time. Predictors of difficult mask ventilation are worth knowing separately from those for intubation, and include a beard, obesity, edentulousness, age over 55 and a history of snoring.

Supraglottic airway devices sit above the larynx and provide a patent airway without instrumenting the trachea. Their limitation is that they do not reliably protect against aspiration, which is why they are avoided where the stomach is full.

Tracheal intubation provides a definitive airway with aspiration protection, and confirmation is essential.

Waveform capnography is the standard for confirming tracheal placement. A sustained carbon dioxide trace over several breaths confirms it; oesophageal placement produces at most a small transient trace that disappears. Auscultation and chest movement are supportive but not definitive.

4. The Failed Airway

The critical situation is can't intubate, can't oxygenate, and its management is defined by the fact that time is measured in minutes.

The sequence is to optimise and attempt bag-mask ventilation, attempt a supraglottic airway, and if oxygenation still cannot be achieved, proceed immediately to a surgical airway.

Limiting attempts is itself an intervention. Guidelines cap laryngoscopy attempts at a small number, typically three plus one by a more experienced operator, precisely because further attempts convert a difficult airway into an impossible one through bleeding and oedema.

Front of neck access is the final step and must not be delayed by further attempts. The cricothyroid membrane is the target, because it is superficial, palpable and relatively avascular, lying between the thyroid and cricoid cartilages.

In children under about 12 years the cricoid is the narrowest part of the airway and its only complete ring, so surgical cricothyroidotomy risks subglottic stenosis and needle cricothyroidotomy with oxygenation is used instead as a temporising measure.

5. The Anticipated Difficult Airway

Where difficulty is predicted, the plan changes fundamentally.

Awake intubation preserves spontaneous ventilation and airway tone, which is precisely what general anaesthesia removes, so the patient continues to oxygenate themselves while the airway is secured.

Awake flexible bronchoscopic intubation is the reference technique, performed with topical anaesthesia and light sedation, and it is chosen for severely restricted mouth opening, fixed cervical spine deformity, upper airway tumour and previously documented failed intubation.

Videolaryngoscopy has changed practice substantially, providing a view around the tongue without requiring axis alignment, and it improves glottic view and first-pass success particularly in patients with limited neck movement. Its characteristic pitfall is that a good view does not guarantee easy tube passage, since the camera sees around a corner that the tube must still negotiate, which is why a stylet or bougie shaped to the blade is used.

The most important part of the plan is stating it aloud. Before induction, the team should know what plan A, plan B and plan C are, who will perform front of neck access if required, and where the equipment is.

6. Rapid Sequence Induction

Used where the stomach is not empty and the aim is to minimise the interval between loss of consciousness and a protected airway.

The components are preoxygenation, a predetermined dose of induction agent, a rapidly acting neuromuscular blocker, and intubation without intervening bag-mask ventilation.

Suxamethonium acts within about a minute and wears off within minutes, which historically made it the agent of choice because failure to intubate could be followed by recovery of spontaneous ventilation.

Its adverse effects are examined repeatedly: hyperkalaemia, particularly dangerous in burns beyond 24 hours, denervation injury and prolonged immobility; malignant hyperthermia; bradycardia especially in children and with repeat doses; raised intraocular, intragastric and intracranial pressure; and myalgia.

Rocuronium at intubating dose is an alternative, with the important property that its effect can be reversed rapidly by sugammadex, which has weakened the traditional argument for suxamethonium.

Cricoid pressure remains controversial. It was intended to occlude the oesophagus against the vertebral body, but the evidence for benefit is weak, imaging shows the oesophagus is frequently lateral rather than directly posterior, and the manoeuvre can worsen the laryngeal view and impede ventilation. It is therefore released if it interferes with either.

7. Aspiration and Fasting

Aspiration of gastric contents is the complication that rapid sequence induction exists to prevent, and understanding the risk explains the rules around it.

The danger depends on what is aspirated. Acidic fluid causes a chemical pneumonitis, described as Mendelson syndrome, with bronchospasm, hypoxia and diffuse infiltrates. Particulate matter causes obstruction and a subsequent inflammatory response. Volume and acidity together determine severity.

Fasting guidelines follow gastric emptying rather than convenience. Clear fluids empty within about two hours, breast milk in about four, formula and a light meal in about six, and a fatty meal in eight.

Prolonged starvation is not safer and is actively harmful, causing dehydration, hypoglycaemia in children and discomfort, which is why encouraging clear fluids up to two hours before surgery is now standard rather than exceptional.

Certain patients are never considered fasted regardless of the clock. Pregnancy beyond the first trimester, because progesterone reduces lower oesophageal sphincter tone and the uterus raises intragastric pressure. Trauma, because gastric emptying stops at the moment of injury rather than at the last meal. Bowel obstruction, gastroparesis in longstanding diabetes, and raised intra-abdominal pressure.

Pharmacological prophylaxis reduces volume and acidity where risk is high, using a proton pump inhibitor or an H2 antagonist, and sodium citrate as a non-particulate antacid where immediate neutralisation is required.

8. Extubation and the Paediatric Airway

Extubation is a decision, not an event

Extubation carries risk comparable to intubation and receives far less planning, which is why a substantial proportion of serious airway complications occur at or after this point rather than at induction.

The patient must be able to maintain and protect the airway, oxygenate and ventilate, and clear secretions. Neuromuscular blockade must be fully reversed, and residual paralysis is a leading contributor to postoperative respiratory complications, which is why quantitative monitoring rather than clinical assessment is used to confirm recovery.

Laryngospasm is the characteristic complication. It is a reflex closure of the cords triggered by secretions, blood or airway manipulation during light anaesthesia, and it is commonest in children and in smokers. Management is removal of the stimulus, continuous positive airway pressure with 100 per cent oxygen and jaw thrust, deepening anaesthesia, and a small dose of suxamethonium if hypoxia is developing.

Negative pressure pulmonary oedema follows forceful inspiration against a closed glottis, and it presents with pink frothy secretions and hypoxia shortly after an episode of obstruction.

Why the paediatric airway is different

Four differences matter and all point the same way.

The airway is absolutely smaller, and resistance rises with the fourth power of the radius, so a millimetre of oedema removes far more of a child's lumen than an adult's.

The larynx sits higher and more anteriorly, and the epiglottis is longer, floppier and more angled, which changes laryngoscopy technique.

The occiput is relatively large, so a neutral position is achieved with a shoulder roll rather than by placing a pillow under the head.

Oxygen consumption is roughly twice the adult rate per kilogram with a smaller functional residual capacity, so desaturation follows apnoea in seconds.

9. Worked Examples

Example 1. After two failed laryngoscopy attempts the patient cannot be ventilated by mask and saturation is 82 per cent and falling. A third attempt is proposed with a different blade. Comment.

This is a can't intubate, can't oxygenate situation, and further laryngoscopy is the wrong response.

The reasoning is that oxygenation, not intubation, is the goal, and each additional attempt causes bleeding and oedema that make both mask ventilation and any subsequent attempt harder. Attempts are therefore capped deliberately.

The correct sequence is to optimise and reattempt bag-mask ventilation with two-person technique, adjuncts and jaw thrust, then place a supraglottic airway, and if oxygenation still cannot be achieved, proceed to front of neck access without further delay.

The cricothyroid membrane is the target because it is superficial, palpable and relatively avascular. Announcing the situation aloud matters, because it changes what the whole team does and prevents the drift into repeated attempts that characterises these events in case reviews.

Example 2. Why do children, pregnant women and obese patients desaturate so much faster during apnoea?

Because all three have the same problem from different causes: a smaller oxygen reservoir combined with a higher rate of consumption.

Safe apnoea time depends on the oxygen stored in the functional residual capacity divided by the rate at which it is consumed.

Children consume oxygen at roughly twice the adult rate per kilogram while having a proportionally smaller functional residual capacity, so the numerator is small and the denominator large.

In pregnancy the gravid uterus splints the diaphragm and reduces functional residual capacity by around 20 per cent, while oxygen consumption rises to meet fetal and maternal demand.

In obesity the mass of the chest wall and abdomen reduces functional residual capacity, and increased metabolically active tissue raises consumption.

The practical consequences are the same in all three: preoxygenate thoroughly, position head-up to increase functional residual capacity where possible, and recognise that the interval between apnoea and desaturation may be under a minute rather than several.

Example 3. A patient with 40 per cent burns sustained five days ago requires intubation. Why is suxamethonium contraindicated?

Because of the risk of life-threatening hyperkalaemia.

The mechanism is upregulation of acetylcholine receptors. After burns, denervation injury or prolonged immobility, muscle responds by proliferating extrajunctional acetylcholine receptors across the whole membrane rather than confining them to the neuromuscular junction, and these receptors include immature isoforms with prolonged open times.

Suxamethonium is a depolarising agent, so it opens every one of those receptors simultaneously, and potassium efflux occurs across the entire muscle surface rather than at the endplate alone. The resulting rise in serum potassium can be several millimoles per litre and can precipitate ventricular arrhythmia and cardiac arrest.

The timing matters and is examinable. The risk is not present in the first 24 to 48 hours, because receptor upregulation takes time to develop, and it persists for months after the injury.

The alternative is rocuronium at intubating dose, which is non-depolarising and can be reversed rapidly with sugammadex if intubation fails.

Example 4. A patient with severe oral submucous fibrosis and 1.5 cm mouth opening requires surgery. How would you plan the airway?

The plan is awake flexible bronchoscopic intubation, with a surgical airway plan prepared and stated.

Direct laryngoscopy is impossible with this degree of mouth opening, since the blade cannot be introduced, and videolaryngoscopy is equally limited because it still requires a route into the mouth. Inducing anaesthesia would therefore remove spontaneous ventilation and airway tone in a patient who cannot be intubated conventionally and may not be ventilable by mask because of restricted mouth opening and mask seal.

Awake intubation avoids this by preserving the patient's own ventilation and protective reflexes throughout. Topical anaesthesia of the nasal passage, oropharynx and larynx with light sedation permits a flexible bronchoscope to be passed nasally, and the tube is railroaded over it once the trachea is entered.

Oral submucous fibrosis is common in India because of areca nut and gutkha use, and mouth opening should be measured at the preoperative visit rather than assumed, since patients rarely volunteer the problem.

Example 5. After intubation, a colleague confirms placement by auscultating both axillae and observing chest rise. Is this sufficient?

No. Waveform capnography is required, and it is the standard of care for confirming tracheal placement.

The reasoning is that auscultation and chest movement can both be misleading. Gastric insufflation produces sounds transmitted to the chest, chest movement can be produced by ventilation of the oesophagus and stomach, and both signs are difficult to assess reliably in an obese or noisy environment.

Capnography confirms placement because carbon dioxide is returned only from ventilated lung. A sustained waveform maintained over at least six breaths confirms tracheal placement, while oesophageal intubation may produce a small initial trace from gas that entered the stomach during mask ventilation, but that trace diminishes rapidly and does not sustain.

The clinical importance is that unrecognised oesophageal intubation remains a cause of avoidable death and brain injury, and it is almost entirely preventable by this single measurement. The same monitoring also detects displacement later, which is why it continues throughout anaesthesia and transfer.

Summary

Oxygenation is the goal; intubation is one means to it.

Repeated attempts convert a difficult airway into an impossible one.

Airway assessment predicts poorly, so prepare for failure in every case.

Previous difficult intubation is the most useful single predictor.

Oral submucous fibrosis is a common Indian cause of severe trismus.

Preoxygenation denitrogenates the functional residual capacity and buys apnoea time.

Children, pregnant women and obese patients desaturate within a minute.

Head-up positioning improves preoxygenation in obesity and pregnancy.

A nasopharyngeal airway is tolerated with an intact gag reflex; an oropharyngeal one is not.

Bag-mask ventilation is more important than intubation.

Supraglottic airways do not reliably protect against aspiration.

Waveform capnography is the standard for confirming tracheal placement.

Auscultation and chest rise are supportive but not definitive.

In can't intubate can't oxygenate, proceed to front of neck access without delay.

The cricothyroid membrane is superficial, palpable and relatively avascular.

Cricothyroidotomy is avoided under about 12 years because the cricoid is the only complete ring.

Awake intubation preserves spontaneous ventilation and is used where difficulty is predicted.

Suxamethonium causes hyperkalaemia in burns beyond 24 hours, denervation and immobility.

Rocuronium with sugammadex reversal is a genuine alternative for rapid sequence induction.

Cricoid pressure is released if it worsens the view or impedes ventilation.

Key formulas & results

Everything to memorise for the exam hall, in one card. Screenshot this for revision.

The organising tool

OXYGENATION IS THE GOAL. INTUBATION IS ONLY ONE WAY OF ACHIEVING IT.

PATIENTS DIE BECAUSE OXYGEN DELIVERY STOPPED WHILE ATTEMPTS CONTINUED, NOT BECAUSE A TUBE COULD NOT BE PLACED.

Why attempts are capped

EACH LARYNGOSCOPY TRAUMATISES TISSUE, PRODUCES BLEEDING AND OEDEMA, AND CONVERTS AN AIRWAY THAT COULD BE MASK-VENTILATED INTO ONE THAT CANNOT.

GUIDELINES LIMIT ATTEMPTS TO ABOUT THREE PLUS ONE BY A MORE EXPERIENCED OPERATOR. LIMITING ATTEMPTS IS ITSELF AN INTERVENTION.

Prediction versus preparation

NO BEDSIDE TEST HAS BOTH GOOD SENSITIVITY AND GOOD SPECIFICITY, SO PLAN FOR FAILURE IN EVERY CASE.

THE ANSWER TO POOR PREDICTION IS NOT A BETTER TEST BUT A STATED PLAN A, B AND C BEFORE INDUCTION, WITH ROLES AND EQUIPMENT AGREED.

Mallampati technique

PATIENT SITTING, MOUTH OPEN, TONGUE PROTRUDED, WITHOUT PHONATION. CLASS I SHOWS SOFT PALATE, FAUCES, UVULA AND PILLARS; CLASS IV SHOWS ONLY HARD PALATE.

PHONATING RAISES THE PALATE AND FALSELY IMPROVES THE GRADE, WHICH IS WHY THE PATIENT IS ASKED NOT TO SAY AH.

Other bedside predictors

THYROMENTAL DISTANCE BELOW ABOUT 6 CM, MOUTH OPENING BELOW ABOUT 3 CM, AND LIMITED NECK EXTENSION.

NECK EXTENSION MATTERS BECAUSE CLASSICAL LARYNGOSCOPY ALIGNS THE ORAL, PHARYNGEAL AND LARYNGEAL AXES, WHICH LIMITED EXTENSION PREVENTS.

The best single predictor

PREVIOUS DIFFICULT INTUBATION.

IT OUTPERFORMS EVERY ANATOMICAL TEST, WHICH IS WHY IT IS ASKED FIRST AND WHY DOCUMENTED DIFFICULTY MUST BE RECORDED AND COMMUNICATED TO THE PATIENT.

Difficult mask ventilation predictors

BEARD, OBESITY, EDENTULOUSNESS, AGE OVER 55, AND A HISTORY OF SNORING.

THESE DIFFER FROM THE PREDICTORS OF DIFFICULT INTUBATION AND MATTER MORE, SINCE A PATIENT WHO CAN BE MASK-VENTILATED HAS TIME.

Preoxygenation physiology

BREATHING 100 PER CENT OXYGEN REPLACES NITROGEN IN THE FUNCTIONAL RESIDUAL CAPACITY WITH OXYGEN, CREATING A RESERVOIR THAT SUSTAINS SATURATION DURING APNOEA.

IT EXTENDS SAFE APNOEA TIME FROM AROUND ONE MINUTE TO SEVERAL IN A HEALTHY ADULT, AND IT IS THE STEP MOST OFTEN PERFORMED INADEQUATELY.

Who desaturates fastest

CHILDREN, PREGNANT WOMEN AND OBESE PATIENTS, ALL BECAUSE OF A SMALLER FUNCTIONAL RESIDUAL CAPACITY COMBINED WITH HIGHER OXYGEN CONSUMPTION.

HEAD-UP POSITIONING IMPROVES PREOXYGENATION IN PREGNANCY AND OBESITY BY INCREASING FUNCTIONAL RESIDUAL CAPACITY.

Choosing an adjunct

AN OROPHARYNGEAL AIRWAY IS NOT TOLERATED WITH AN INTACT GAG REFLEX. A NASOPHARYNGEAL AIRWAY IS.

THIS MAKES THE NASOPHARYNGEAL AIRWAY THE ADJUNCT OF CHOICE IN THE SEMICONSCIOUS PATIENT WHO STILL HAS PROTECTIVE REFLEXES.

The supraglottic limitation

SUPRAGLOTTIC AIRWAY DEVICES PROVIDE A PATENT AIRWAY BUT DO NOT RELIABLY PROTECT AGAINST ASPIRATION.

THIS IS WHY THEY ARE AVOIDED WHERE THE STOMACH IS FULL, AND WHY THEY ARE A RESCUE RATHER THAN A DEFINITIVE AIRWAY IN THAT SETTING.

Confirming placement

WAVEFORM CAPNOGRAPHY SUSTAINED OVER AT LEAST SIX BREATHS CONFIRMS TRACHEAL PLACEMENT. OESOPHAGEAL PLACEMENT PRODUCES AT MOST A SMALL TRANSIENT TRACE THAT DISAPPEARS.

AUSCULTATION AND CHEST RISE ARE SUPPORTIVE BUT NOT DEFINITIVE, AND UNRECOGNISED OESOPHAGEAL INTUBATION REMAINS A CAUSE OF AVOIDABLE DEATH.

The failed airway sequence

OPTIMISE AND ATTEMPT MASK VENTILATION, THEN A SUPRAGLOTTIC AIRWAY, THEN FRONT OF NECK ACCESS WITHOUT FURTHER DELAY.

THE DECISION POINT IS OXYGENATION, NOT INTUBATION. ANNOUNCING THE SITUATION ALOUD CHANGES WHAT THE WHOLE TEAM DOES.

Why the cricothyroid membrane

IT IS SUPERFICIAL, PALPABLE AND RELATIVELY AVASCULAR, LYING BETWEEN THE THYROID AND CRICOID CARTILAGES.

IN CHILDREN UNDER ABOUT 12 THE CRICOID IS THE NARROWEST PART OF THE AIRWAY AND ITS ONLY COMPLETE RING, SO NEEDLE TECHNIQUE REPLACES SURGICAL CRICOTHYROIDOTOMY.

Why awake intubation works

IT PRESERVES SPONTANEOUS VENTILATION AND AIRWAY TONE, WHICH IS PRECISELY WHAT GENERAL ANAESTHESIA REMOVES.

AWAKE FLEXIBLE BRONCHOSCOPIC INTUBATION IS THE REFERENCE TECHNIQUE FOR SEVERE TRISMUS, FIXED CERVICAL DEFORMITY, AIRWAY TUMOUR AND DOCUMENTED PREVIOUS FAILURE.

The videolaryngoscopy pitfall

A GOOD VIEW DOES NOT GUARANTEE EASY TUBE PASSAGE, BECAUSE THE CAMERA SEES AROUND A CORNER THAT THE TUBE MUST STILL NEGOTIATE.

A STYLET OR BOUGIE SHAPED TO THE BLADE IS USED, AND FAILURE TO PREPARE ONE IS A COMMON CAUSE OF FAILED INTUBATION DESPITE AN EXCELLENT VIEW.

Rapid sequence induction

PREOXYGENATION, A PREDETERMINED INDUCTION DOSE, A RAPIDLY ACTING NEUROMUSCULAR BLOCKER, AND INTUBATION WITHOUT INTERVENING BAG-MASK VENTILATION.

THE AIM IS TO MINIMISE THE INTERVAL BETWEEN LOSS OF CONSCIOUSNESS AND A PROTECTED AIRWAY IN A PATIENT WHOSE STOMACH IS NOT EMPTY.

Suxamethonium adverse effects

HYPERKALAEMIA, MALIGNANT HYPERTHERMIA, BRADYCARDIA ESPECIALLY IN CHILDREN AND WITH REPEAT DOSES, RAISED INTRAOCULAR, INTRAGASTRIC AND INTRACRANIAL PRESSURE, AND MYALGIA.

ITS ADVANTAGE WAS RAPID OFFSET ALLOWING RETURN OF SPONTANEOUS VENTILATION, AN ARGUMENT WEAKENED BY SUGAMMADEX REVERSAL OF ROCURONIUM.

The hyperkalaemia mechanism

BURNS, DENERVATION AND PROLONGED IMMOBILITY UPREGULATE EXTRAJUNCTIONAL ACETYLCHOLINE RECEPTORS ACROSS THE WHOLE MUSCLE MEMBRANE.

SUXAMETHONIUM OPENS ALL OF THEM AT ONCE, SO POTASSIUM EFFLUX OCCURS OVER THE ENTIRE SURFACE RATHER THAN AT THE ENDPLATE ALONE.

The timing of that risk

NOT PRESENT IN THE FIRST 24 TO 48 HOURS, BECAUSE RECEPTOR UPREGULATION TAKES TIME TO DEVELOP, AND PERSISTING FOR MONTHS AFTER THE INJURY.

THIS TIMING IS EXAMINED DIRECTLY, SINCE IT DETERMINES WHETHER SUXAMETHONIUM IS SAFE IN A GIVEN BURNS OR SPINAL INJURY PATIENT.

Cricoid pressure

EVIDENCE FOR BENEFIT IS WEAK, IMAGING SHOWS THE OESOPHAGUS IS FREQUENTLY LATERAL RATHER THAN POSTERIOR, AND IT CAN WORSEN THE VIEW AND IMPEDE VENTILATION.

IT IS RELEASED IF IT INTERFERES WITH EITHER LARYNGOSCOPY OR VENTILATION, WHICH REVERSES OLDER TEACHING THAT IT MUST BE MAINTAINED.

Fasting intervals

CLEAR FLUIDS TWO HOURS, BREAST MILK FOUR, FORMULA AND LIGHT MEAL SIX, FATTY MEAL EIGHT.

PROLONGED STARVATION IS NOT SAFER AND CAUSES DEHYDRATION, HYPOGLYCAEMIA IN CHILDREN AND DISCOMFORT, SO CLEAR FLUIDS TO TWO HOURS ARE ENCOURAGED.

Never considered fasted

PREGNANCY BEYOND THE FIRST TRIMESTER, TRAUMA, BOWEL OBSTRUCTION, GASTROPARESIS AND RAISED INTRA-ABDOMINAL PRESSURE.

IN TRAUMA, GASTRIC EMPTYING STOPS AT THE MOMENT OF INJURY RATHER THAN AT THE LAST MEAL, SO THE CLOCK IS COUNTED FROM THE ACCIDENT.

Laryngospasm

REFLEX CORD CLOSURE TRIGGERED BY SECRETIONS, BLOOD OR MANIPULATION DURING LIGHT ANAESTHESIA, COMMONEST IN CHILDREN AND SMOKERS.

REMOVE THE STIMULUS, APPLY CONTINUOUS POSITIVE AIRWAY PRESSURE WITH 100 PER CENT OXYGEN AND JAW THRUST, DEEPEN ANAESTHESIA, AND GIVE SMALL-DOSE SUXAMETHONIUM IF HYPOXIA DEVELOPS.

NEET PG test series

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Traps NEET PG sets — and how to dodge them

These are the exact option-traps and misreads that cost marks under negative marking.

WATCH OUT

✗ Persisting with laryngoscopy in a desaturating patient

✓ Oxygenation is the goal, and each further attempt causes bleeding and oedema that make mask ventilation and any subsequent attempt harder. The sequence moves to mask ventilation, then a supraglottic airway, then front of neck access.

WATCH OUT

✗ Relying on a reassuring airway assessment

✓ No bedside test has both good sensitivity and good specificity, so a normal Mallampati grade does not exclude difficulty. The correct response is a stated plan A, B and C with equipment and roles agreed before induction.

WATCH OUT

✗ Asking the patient to say ah during Mallampati assessment

✓ Phonation raises the soft palate and falsely improves the grade, which underestimates difficulty. The assessment is made with the patient sitting, mouth open and tongue protruded, without phonation.

WATCH OUT

✗ Assessing intubation difficulty without assessing mask ventilation

✓ A beard, obesity, edentulousness, age over 55 and snoring predict difficult mask ventilation and differ from the intubation predictors. Difficult mask ventilation matters more, because a patient who can be ventilated has time.

WATCH OUT

✗ Preoxygenating inadequately in a rapidly desaturating patient

✓ Children, pregnant women and obese patients have reduced functional residual capacity with raised oxygen consumption, so safe apnoea time may be under a minute. Full denitrogenation and head-up positioning are what create the window for everything else.

WATCH OUT

✗ Using a supraglottic airway in a patient with a full stomach

✓ These devices sit above the larynx and do not reliably protect against aspiration. In a patient at risk they are a rescue measure while a definitive airway is arranged, not a planned technique.

WATCH OUT

✗ Confirming intubation by auscultation and chest rise alone

✓ Gastric insufflation transmits sounds to the chest and can produce apparent chest movement, and both signs are unreliable in obese or noisy environments. Sustained waveform capnography over at least six breaths is the standard.

WATCH OUT

✗ Performing surgical cricothyroidotomy in a small child

✓ The cricoid is the narrowest part of the paediatric airway and its only complete cartilaginous ring, so incising the cricothyroid membrane risks subglottic stenosis. Needle cricothyroidotomy with oxygenation temporises until a definitive airway is achieved.

WATCH OUT

✗ Inducing anaesthesia in a patient with severe trismus

✓ Induction removes spontaneous ventilation and airway tone in a patient who cannot be intubated conventionally and may not be mask-ventilable. Awake flexible bronchoscopic intubation preserves the patient's own ventilation throughout.

WATCH OUT

✗ Assuming a good videolaryngoscopic view guarantees intubation

✓ The camera sees around a corner that the tube must still negotiate, so tube delivery can fail despite an excellent view. A stylet or bougie shaped to match the blade is prepared before the attempt.

WATCH OUT

✗ Giving suxamethonium to a patient with burns of one week

✓ Extrajunctional acetylcholine receptor upregulation develops over 24 to 48 hours and persists for months, so depolarisation releases potassium across the whole muscle surface and can cause cardiac arrest. Rocuronium with sugammadex is the alternative.

WATCH OUT

✗ Maintaining cricoid pressure despite a poor view

✓ Evidence for benefit is weak and imaging shows the oesophagus is frequently lateral to the cricoid rather than directly behind it, while the manoeuvre can worsen laryngoscopy and impede ventilation. It is released if it interferes.

WATCH OUT

✗ Starving patients from midnight for an afternoon list

✓ Clear fluids empty within about two hours, and prolonged fasting causes dehydration, hypoglycaemia in children and discomfort without reducing aspiration risk. Encouraging clear fluids up to two hours before surgery is current practice.

WATCH OUT

✗ Counting fasting time from the last meal in a trauma patient

✓ Gastric emptying halts at the moment of injury because of pain and sympathetic activation, so a patient who ate hours before an accident may still have a full stomach. Trauma patients are treated as unfasted regardless of the interval.

WATCH OUT

✗ Treating extubation as a routine end to the case

✓ A substantial proportion of serious airway complications occur at or after extubation rather than at induction. Full reversal of neuromuscular blockade confirmed by quantitative monitoring, adequate oxygenation and airway protection are checked deliberately.

WATCH OUT

✗ Giving a full paralysing dose immediately for laryngospasm

✓ Most episodes resolve with removal of the stimulus, jaw thrust and continuous positive airway pressure with 100 per cent oxygen, and deepening anaesthesia. Small-dose suxamethonium is reserved for developing hypoxia rather than used first.

Exam-pattern practice

PYQ-style questions with full solutions. Work through them as a readiness check — mark yourself honestly and get your gap report at the end.

Readiness check

Are you exam-ready for "Airway Management & Difficult Airway"?

9 problems from this chapter. Try each one, reveal the worked solution, mark yourself honestly — get your gap report at the end.

9 questions~6 min

5-minute revision

The whole chapter, distilled. Read this the night before the exam.

•Oxygenation is the goal; intubation is one means.
•Repeated attempts convert difficult airways into impossible ones.
•Attempts are capped at about three plus one by a senior operator.
•Airway assessment predicts poorly, so prepare for failure always.
•Previous difficult intubation is the best single predictor.
•Mallampati is assessed sitting, without phonation.
•Thyromental distance below 6 cm suggests difficulty.
•Mouth opening below 3 cm limits instrumentation.
•Neck extension is needed to align the three axes.
•Beard, obesity, edentulousness, age and snoring predict difficult mask ventilation.
•Oral submucous fibrosis causes severe trismus in Indian practice.
•Preoxygenation denitrogenates the functional residual capacity.
•It extends safe apnoea from about one minute to several.
•Children, pregnant and obese patients desaturate fastest.
•Head-up positioning improves preoxygenation.
•A nasopharyngeal airway is tolerated with an intact gag reflex.
•Bag-mask ventilation matters more than intubation.
•Supraglottic devices do not protect against aspiration.
•Waveform capnography over six breaths confirms placement.
•Auscultation and chest rise are not definitive.
•In can't intubate can't oxygenate, go to front of neck access.
•The cricothyroid membrane is superficial and avascular.
•Cricothyroidotomy is avoided under about 12 years.
•Awake intubation preserves spontaneous ventilation.
•Awake bronchoscopic intubation is the reference technique.
•Videolaryngoscopy improves view but not always tube delivery.
•Prepare a stylet or bougie shaped to the blade.
•State plan A, B and C aloud before induction.
•Rapid sequence induction omits bag-mask ventilation.
•Suxamethonium acts in a minute and wears off in minutes.
•It causes hyperkalaemia in burns, denervation and immobility.
•The risk begins after 24 to 48 hours and lasts months.
•It also causes malignant hyperthermia and bradycardia.
•It raises intraocular, intragastric and intracranial pressure.
•Rocuronium with sugammadex is a genuine alternative.
•Cricoid pressure evidence is weak and it can worsen the view.
•Release cricoid pressure if it impedes anything.
•Clear fluids empty in two hours.
•Breast milk empties in four hours.
•Formula and light meals empty in six hours.
•Prolonged starvation is not safer.
•Pregnancy beyond the first trimester is never fasted.
•Trauma stops gastric emptying at the moment of injury.
•Aspiration of acid causes chemical pneumonitis.
•Extubation carries risk comparable to intubation.
•Residual paralysis contributes to postoperative complications.
•Quantitative monitoring confirms reversal.
•Laryngospasm is commonest in children and smokers.
•Treat it with CPAP, jaw thrust and 100 per cent oxygen.
•Small-dose suxamethonium is reserved for developing hypoxia.
•Negative pressure pulmonary oedema follows obstruction.
•The paediatric airway is smaller with a higher, anterior larynx.
•The large occiput requires a shoulder roll for neutral position.
•Children desaturate within seconds of apnoea.

NEET PG question blueprint

How this topic is asked, tier by tier — so you can prep to the pattern.

Typical weightage: Each NEET PG question is worth +4/-1; airway management contributes 5-7 questions per attempt and overlaps with Surgery, Emergency Medicine and Paediatrics

Question style	Marks each	Typical count	What it tests
Predicting difficulty	4	~1	Bedside tests, their limitations, and predictors of difficult mask ventilation
Preoxygenation	4	~1	Denitrogenation physiology and the groups who desaturate fastest
Confirming placement	4	~1	Waveform capnography and the unreliability of clinical signs
Failed airway	4	~1	The can't intubate can't oxygenate sequence and front of neck access
Anticipated difficulty	4	~1	Awake intubation, videolaryngoscopy and planning
Suxamethonium	4	~1	Adverse effects, the hyperkalaemia mechanism and its timing
Cricoid pressure	4	~1	The evidence position and when to release it
Fasting and aspiration	4	~1	Fasting intervals and the patients never considered fasted
Extubation	4	~1	Laryngospasm management and why extubation carries comparable risk

Exam-hall strategy

Battle-tested tips from mentors and toppers for this topic under the sectional clock.

In any desaturating stem, choose the option that restores oxygenation.
Count the attempts described; more than three signals the wrong answer.
For burns and denervation stems, check the interval before choosing suxamethonium.
In a paediatric surgical airway stem, needle technique is the answer.
For confirmation of tube placement, capnography beats every clinical sign.
Where mouth opening is severely limited, the answer is awake intubation.
Treat trauma and pregnancy as unfasted regardless of the stated interval.
With NEET PG's +4/-1 marking, the fasting intervals, suxamethonium adverse effects and cricothyroidotomy anatomy are high-certainty recall worth banking early.
Under the 5-group, 42-minute time-bound format, clear those fast and spend the remaining time on the failed airway and rapid sequence stems, since a closed group cannot be reopened.

Beyond the exam

Where this skill shows up in the job you're competing for — and in life.

Saying the plan out loud before induction

Naming plan A, B and C, and who will cut the neck if needed, converts a difficult airway from an individual problem into a team procedure with an agreed sequence.

Sitting the obese patient up to preoxygenate

Head-up positioning increases functional residual capacity and can double the safe apnoea time, which is the window within which every subsequent decision is made.

Watching the capnograph rather than the chest

Six sustained waveforms confirm what auscultation cannot, and unrecognised oesophageal intubation remains a preventable cause of death and brain injury.

Offering water two hours before the list

Clear fluids to two hours reduces dehydration, hypoglycaemia and induction hypotension without any increase in aspiration risk, and replaces a habit that has no evidence behind it.

Where else this topic is tested

Prepare once, score in every exam that asks it.

FMGE / NExTVery high overlap — difficult airway prediction, suxamethonium, capnography and cricothyroidotomy are examined at identical depth

USMLE Step 2 CKHigh overlap — rapid sequence induction, aspiration risk and airway emergencies are shared, with more emphasis on emergency department algorithms

MD Anaesthesiology and DNB entranceFoundational — assumed working knowledge, with difficult airway society algorithms, fibreoptic technique and airway equipment examined far more deeply

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Questions aspirants ask

Pulled from the Q&A community and mentor sessions.

Because each attempt changes the airway for the worse, and the deterioration is cumulative and rapid. A laryngoscope blade applied to the tongue base and vallecula compresses tissue, and repeated application produces oedema. Contact with the epiglottis, arytenoids and posterior pharyngeal wall causes bleeding, and blood in the airway obscures the view for any subsequent attempt including a fibreoptic one, which is particularly damaging since flexible bronchoscopy is the rescue technique most degraded by blood. Soft tissue swelling then reduces the space available and worsens the mask seal, so an airway that was mask-ventilable at the start becomes progressively harder to ventilate. Case analyses of airway-related deaths repeatedly show the same trajectory: multiple attempts, progressive deterioration in the ability to oxygenate, and a delayed decision to perform front of neck access made after hypoxia is already established. This is why modern guidelines specify a numerical limit, commonly three attempts by the primary operator plus one by a more experienced colleague, and why they emphasise changing something between attempts rather than repeating the same technique. It is also why the guidelines instruct the team to declare the situation aloud, since naming a can't intubate can't oxygenate event is what converts a drifting series of attempts into a structured rescue.

Because the amount of potassium released depends on how many acetylcholine receptors the drug can open, and certain conditions dramatically increase that number. In healthy muscle, acetylcholine receptors are confined almost entirely to the neuromuscular junction, occupying a tiny fraction of the total membrane surface. Suxamethonium depolarises those receptors, releasing a small quantity of potassium that raises serum concentration by only a few tenths of a millimole per litre, which is clinically insignificant. After a burn, denervation injury such as spinal cord transection or stroke, prolonged immobility, or severe sepsis with critical illness myopathy, muscle responds to reduced neural activity by proliferating extrajunctional receptors across the entire membrane, including immature gamma-subunit isoforms whose channels remain open longer. Suxamethonium now depolarises the whole muscle surface simultaneously, and potassium leaves through vastly more channels for longer. Rises of five to ten millimoles per litre have been reported, sufficient to cause ventricular fibrillation and asystole. The timing follows the biology of receptor synthesis: upregulation requires 24 to 48 hours to develop, so the drug is safe immediately after injury, and receptors persist for months until reinnervation or healing occurs. The safe alternative is rocuronium, which is non-depolarising and now rapidly reversible with sugammadex.

Because the anatomical premise turned out to be shaky, the evidence for benefit never materialised, and the harms are demonstrable. The technique was introduced on the reasoning that firm posterior pressure on the cricoid cartilage, the only complete ring in the airway, would compress the oesophagus against the vertebral body and prevent passive regurgitation during induction. Three lines of evidence have undermined it. Imaging studies using magnetic resonance and computed tomography show that the oesophagus lies lateral to the midline in a substantial proportion of people and is displaced further laterally by the pressure itself, so the structure being compressed may not be the oesophagus at all. Randomised and observational data have failed to demonstrate a reduction in clinically important aspiration, and the outcome is rare enough that adequately powered trials are difficult. Meanwhile the harms are measurable: cricoid pressure worsens the laryngoscopic view in a proportion of patients, impairs mask ventilation, hinders placement of a supraglottic device, and applied to an actively vomiting patient may risk oesophageal rupture. The current position in most guidelines is that it remains optional in rapid sequence induction, that force should be modest and correctly applied, and crucially that it is reduced or released whenever it interferes with laryngoscopy or ventilation, because oxygenation takes precedence.

Because it produces real physiological harm without reducing the risk it was intended to address. The purpose of fasting is to reduce gastric volume and acidity at induction, and gastric emptying determines how long that takes. Clear fluids leave the stomach exponentially, with essentially complete emptying within about two hours, and drinking clear fluid actually stimulates emptying rather than delaying it, so a patient given water two hours preoperatively has a smaller residual volume than one starved overnight. Extending the fast beyond that point therefore adds nothing to safety. What it does add is measurable. Dehydration reduces preload and contributes to hypotension at induction, particularly with propofol and with neuraxial blockade. Children become hypoglycaemic and ketotic, and small children are especially vulnerable given limited glycogen stores. Patients are thirsty, hungry, headachy and anxious, which worsens the perioperative experience and can delay recovery. Diabetic patients face particular difficulty balancing medication against an unpredictable fasting period. Enhanced recovery protocols go further, giving carbohydrate-containing clear drinks up to two hours preoperatively, which reduces insulin resistance and improves postoperative wellbeing. The persistence of nil by mouth from midnight reflects institutional habit and list uncertainty rather than evidence, and correcting it is one of the simplest available improvements in perioperative care.

Because extubation reverses every advantage that was carefully assembled for induction, usually with less preparation and often at the end of a long case when attention has moved on. At induction the patient is preoxygenated, monitored, positioned, and attended by a team that is expecting difficulty, with drugs drawn up and equipment checked. At extubation the patient may be partially reversed, still under residual anaesthetic effect, positioned for surgery rather than for airway access, and surrounded by a team beginning to disperse. Several specific mechanisms then operate. Residual neuromuscular blockade impairs pharyngeal function and the ability to maintain a patent airway or protect against aspiration, and clinical tests such as head lift detect it poorly, which is why quantitative monitoring matters. Laryngospasm is triggered by blood or secretions reaching the cords during the light plane traversed on emergence, and it is commonest in children and after airway surgery. Airway oedema from surgery, prolonged intubation or prone positioning may have developed during the case and is not apparent until the tube is removed. And any patient who was difficult to intubate remains difficult, but now with an oedematous and instrumented airway. The response is to treat extubation as a planned procedure with its own risk assessment, criteria and rescue plan.