FESS: Anaesthesia Implications for MD Anaesthesia Viva

Anaesthetic goals

1. Dry, bloodless operative field
2. Immobility
3. Stable haemodynamics and ventilation
4. Protection from aspiration of blood
5. Smooth, non-coughing emergence
6. Early detection and management of rare but catastrophic orbital, vascular, and intracranial complications.

1. Preoperative assessment

History

• Indication and extent of surgery: routine FESS versus tumor, skull-base, orbital, revision, or extensive polyposis surgery.
• Severity of nasal obstruction, mouth breathing, snoring and obstructive sleep apnea.
• Asthma, aspirin-exacerbated respiratory disease, allergic fungal sinusitis.
• Previous surgery, radiation, trauma, difficult airway, prior major epistaxis.
• Drugs:
  • Anticoagulants, antiplatelets, NSAIDs, herbal drugs.
  • Antihypertensives and beta-blockers.
  • Steroids: assess need for perioperative supplementation if prolonged systemic use.
• Comorbidities relevant to controlled hypotension: coronary artery disease, cerebrovascular disease, chronic hypertension, arrhythmias, severe valvular disease, renal impairment, anemia.

Examination and investigations

• Standard airway examination. Nasal route is unavailable, but facial anatomy, mouth opening and OSA are relevant.
• Baseline BP, Hb, coagulation testing where indicated, ECG in appropriate patients.
• Review CT sinuses to understand proximity to orbit, skull base and carotid canal in high-risk surgery.

Important viva point

2. Choice of anaesthetic technique

General anaesthesia

• Complete immobility
• Secure control of ventilation
• Better tolerance of the procedure
• Ability to manage significant bleeding or complications rapidly

TIVA versus volatile anaesthesia

Airway: ETT or supraglottic airway?

• Preferred for prolonged, extensive, revision, skull-base, high-bleeding-risk surgery, reflux/aspiration risk, obesity/OSA, or when controlled ventilation is required.
• Secure the tube well, typically taped to the lower lip/chin and away from the surgical field.
• Use a reinforced tube if tube kinking or surgical interference is anticipated.

• May allow smoother emergence and less coughing.
• May offer improved field conditions in selected low-risk ambulatory cases.
• Disadvantages: less protection against blood and regurgitation, malposition or leakage.
• Miller describes smoother emergence with an SGA but less protection from regurgitation compared with ETT. Miller's Anesthesia, 10e, p. 9812

3. Intraoperative management

Position

• Supine, head elevated 10 to 30 degrees.
• Reverse Trendelenburg/head-up position promotes venous drainage and reduces bleeding.
• Head in neutral position, eyes accessible if possible.
• Protect pressure points.

Monitoring

• Standard ASA monitoring for routine cases.
• Consider arterial line when:
  • Deliberate hypotension is planned in a high-risk patient
  • Major/revision/skull-base/tumor surgery
  • Significant cardiovascular disease
  • Anticipated major blood loss

Measures to optimize the surgical field

Non-pharmacological

• Head-up position.
• Normothermia.
• Avoid hypercapnia, coughing, bucking, hypertension, and tachycardia.
• Avoid excessive PEEP if it worsens venous congestion.
• Ensure adequate depth during stimulation.
• Surgeon-administered topical vasoconstrictors and local infiltration.

Topical vasoconstrictors

• Adrenaline/epinephrine infiltration, often lidocaine 1% with epinephrine 1:100,000.
• Oxymetazoline or xylometazoline pledgets.
• Cocaine-soaked pledgets in some institutions.

• Communicate clearly before topical/infiltration doses.
• Watch for hypertension, tachyarrhythmia, myocardial ischemia, ventricular arrhythmias, pulmonary edema, and seizures with systemic toxicity.
• Avoid intravascular injection: aspiration, incremental injection, dose accounting.
• Be particularly cautious in ischemic heart disease, uncontrolled hypertension, hyperthyroidism, and arrhythmia.

4. Controlled hypotension

Why?

Target

• Individualize the BP target.
• In a healthy normotensive adult, a commonly used target is MAP approximately 60-65 mmHg, provided end-organ perfusion is satisfactory.
• Do not treat a numerical target as more important than patient safety.

Methods

• Adequate depth of anaesthesia and analgesia.
• Propofol-remifentanil TIVA.
• Beta-blockade: esmolol is useful when tachycardia contributes to bleeding.
• Dexmedetomidine can reduce HR and sympathetic responses.
• Vasodilators such as nitroglycerin or sodium nitroprusside may reduce BP, but can cause reflex tachycardia and may be less favorable for the surgical field.
• Magnesium may be an adjunct in selected patients.

Contraindications or major cautions

• Significant coronary artery disease
• Critical cerebrovascular disease
• Severe anemia/hypovolemia
• Severe aortic stenosis or obstructive cardiomyopathy
• Uncontrolled arrhythmias
• Severe renal dysfunction
• Pregnancy and compromised uteroplacental circulation
• Elderly/frail patients or those with poor autoregulatory reserve

5. Fluid and blood management

• Usually low blood loss, but blood loss can become substantial unexpectedly.
• Obtain IV access appropriate to case complexity.
• Use balanced crystalloid judiciously.
• Avoid fluid overload, which can worsen mucosal edema.
• Crossmatch blood for extensive/revision/tumor/skull-base cases.
• Maintain normothermia and correct coagulopathy if present.

6. Critical surgical complications and anaesthetic response

A. Massive hemorrhage

• Inform surgeon and call for help.
• Stop surgery/pack nose.
• 100% oxygen, secure airway, suction continuously.
• Two large-bore IV lines, arterial line, blood products and massive hemorrhage protocol if necessary.
• Correct hypotension, hypocalcemia, acidosis, and coagulopathy.
• Prepare for conversion, interventional radiology, or vascular assistance.

B. Orbital injury or retrobulbar hematoma

• Immediate communication with surgeon.
• This is a vision-threatening emergency.
• Urgent orbital decompression/canthotomy-cantholysis may be required.
• Avoid hypotension in this situation and restore adequate perfusion.

C. CSF leak or intracranial entry

• Stop surgical dissection.
• Maintain stable haemodynamics and avoid coughing/straining.
• Facilitate repair; consider neurosurgical involvement.
• Postoperative observation for CSF rhinorrhea, meningitis, pneumocephalus, and neurological signs.

D. Venous air embolism

• Sudden fall in ETCO₂, hypoxia, hypotension, mill-wheel murmur.
• Stop surgery, flood field, 100% oxygen, support circulation, reduce head elevation if feasible.

E. Aspiration of blood

• Meticulous suctioning.
• Throat pack only if local protocol supports it, with a documented insertion-removal check.
• Suction pharynx thoroughly before emergence.
• Consider awake extubation when bleeding/aspiration risk is significant.

7. Emergence and postoperative care

Emergence

• Ensure full reversal of neuromuscular blockade.
• Thorough oral and pharyngeal suctioning under direct vision where possible.
• Remove throat pack with a documented check.
• Provide analgesia, antiemetic prophylaxis, and adequate oxygenation.
• Consider lidocaine, opioid titration, dexmedetomidine, or remifentanil strategy to blunt emergence responses.
• Extubate fully awake when aspiration risk is present. Deep extubation is only for carefully selected, low-risk patients with a clean airway.

Analgesia

• Paracetamol
• NSAID/COX-2 inhibitor if surgeon permits and bleeding risk is acceptable
• Small titrated opioid doses
• Local infiltration by surgeon

PONV prophylaxis

• Use multimodal prophylaxis: dexamethasone plus ondansetron, with further agents according to risk.
• Minimize opioid use.
• TIVA may also be useful in high-PONV-risk patients.

Postoperative observation

• Epistaxis or concealed swallowed blood
• Airway obstruction/laryngospasm
• Nausea, vomiting and aspiration
• Hypertension causing rebleeding
• Visual symptoms, proptosis, altered consciousness, severe headache, or CSF rhinorrhea

One-minute viva answer