What is the recommended approach for rapid sequence induction in anesthesia for a patient with a full stomach or history of reflux who requires emergency surgery?

Rapid Sequence Induction in Anesthesia

Core Recommendation for Full Stomach/Reflux Patients

For patients with a full stomach or reflux requiring emergency surgery, perform rapid sequence induction using a fast-acting neuromuscular blocking agent (succinylcholine 1-2 mg/kg OR rocuronium 0.9-1.2 mg/kg) combined with a sedative-hypnotic agent, with pre-induction nasogastric decompression when feasible, head-up positioning, and immediate availability of backup airway equipment. 1, 2, 3, 4

Pre-Induction Risk Mitigation

Gastric Decompression

• Insert a large-bore nasogastric tube before induction to decompress the stomach and remove gastric contents in high-risk patients such as those with bowel obstruction or significant gastric distension 2
• Point-of-care gastric ultrasound can assess gastric volume and guide risk stratification, as 6-16% of appropriately fasted patients still have gastric content associated with aspiration risk 1
• Whether to leave the gastric tube in place or remove it before induction remains controversial; if left in place, keep the proximal end open to atmosphere to act as a pressure valve 1

Patient Positioning

• Use semi-Fowler position (head and torso elevated 20-30 degrees) during RSI to reduce aspiration risk and improve first-pass intubation success 2

Pharmacologic Management

Induction Agents

• For hemodynamically unstable patients: use etomidate 0.3 mg/kg or ketamine 1-2 mg/kg 2, 4
• For hemodynamically stable patients: propofol is acceptable 3, 4
• Etomidate provides minimal cardiovascular depression and is preferred in unstable patients 4

Neuromuscular Blocking Agents (Critical Component)

• A neuromuscular blocking agent MUST be administered when a sedative-hypnotic induction agent is used (strong recommendation from the Society of Critical Care Medicine) 1, 4
• Use succinylcholine 1-2 mg/kg OR rocuronium 0.9-1.2 mg/kg for rapid onset and excellent intubation conditions 2, 3, 4, 5
• Rocuronium 0.6-1.2 mg/kg provides intubating conditions in median 1 minute with excellent or good conditions in most patients within 2 minutes 5
• Have sugammadex immediately available when using rocuronium for reversal in "cannot intubate/cannot oxygenate" scenarios 4

Timing and Administration

• Administer sedative-hypnotic and NMBA in rapid succession with immediate endotracheal tube placement before assisted ventilation to minimize aspiration risk 4

Cricoid Pressure: The Evolving Controversy

Current Evidence

• The role of cricoid pressure is highly controversial and no longer universally recommended 1, 3
• French pediatric guidelines suggest NOT performing cricoid pressure during RSI to decrease respiratory complications, as systematic reviews show no scientific evidence supporting its efficacy in preventing aspiration 1
• In vivo imaging demonstrates cricoid pressure produces lateral esophageal displacement and compresses the hypopharynx rather than protecting against aspiration 1

If Cricoid Pressure Is Applied

• Apply initial force of 10 N when patient is awake, increasing to 30 N as consciousness is lost 2
• If direct laryngoscopy proves difficult, release cricoid pressure immediately 2, 3
• Cricoid pressure may make intubation more difficult and does not reliably prevent aspiration 2

Modified RSI Approach (When Appropriate)

Controlled/Modified RSI

• A "controlled" or "modified" RSI approach includes gentle bag-mask ventilation with peak inspiratory pressure <15 cmH₂O if SpO₂ drops below 95% to prevent life-threatening hypoxemia 1, 3
• This approach has shown decreased hypoxemia, hemodynamic complications, and difficult intubation with no observed aspiration events in retrospective studies 1
• The risk of hypoxemia during classic RSI may exceed the risk of aspiration with controlled ventilation in many clinical scenarios 1

Critical Safety Considerations

Equipment Preparedness

• Have video laryngoscopy, supraglottic airways, and surgical airway equipment immediately available 2
• If intubation fails after maximum three attempts, immediately move to failed intubation plan 2

Special Populations

• Dose obese patients based on actual body weight, not ideal body weight, as IBW dosing results in longer time to block and inadequate intubating conditions 5
• Rocuronium is NOT recommended for rapid sequence induction in Cesarean section patients due to inadequate intubating conditions in studies using lower thiopental doses 5
• Geriatric patients (65-80 years) achieve excellent intubating conditions with 0.6 mg/kg rocuronium in median 2.3 minutes without prolonged recovery 5

Additional Aspiration Risk Reduction Strategies

Beyond RSI itself, implement these interventions 1:

• Administration of prokinetics (erythromycin 3 mg/kg 1-2 hours before induction) when time permits
• Select tracheal tube rather than supraglottic airway device
• Consider orogastric/nasogastric tube placement before induction and extubation

Critical Pitfalls to Avoid

• Do NOT use inadequate NMBA doses: full RSI doses are succinylcholine 1-2 mg/kg or rocuronium 0.9-1.2 mg/kg 2, 4, 5
• Do NOT delay emergency surgery excessively for optimization in true surgical emergencies like high-grade bowel obstruction 2
• Do NOT persist with cricoid pressure if it impairs laryngoscopy 2, 3
• Do NOT avoid gentle ventilation if hypoxemia develops during induction, as the risk-benefit calculation favors preventing critical hypoxemia 1
• Recognize that RSI carries its own risks including difficult/failed intubation, esophageal intubation, anaphylaxis, awareness, and airway trauma 1