Introduction:
History of RSI:
History of RSI:
- RSI, or Rapid Sequence Intubation, is a technique developed to secure the airway quickly in situations where the risk of aspiration is high.
- The concept was introduced in the 1970s to address the potential for regurgitation and aspiration during intubation.
- RSI involves rapid administration of an induction agent followed by a neuromuscular blocking agent (NMBA) to ensure optimal intubating conditions and minimize the risk of aspiration.
- The primary goal is to achieve swift and safe endotracheal intubation while reducing the chance of gastric contents entering the lungs.
- Rapid Sequence Induction and Intubation (RSII) is designed to prevent aspiration risk during anesthesia induction.
- RSII ensures swift establishment of a protected airway to minimize the risk of passive or active regurgitation.
- It deviates from the traditional induction approach by prioritizing quick endotracheal tube cuff inflation.
Differences from Usual Induction:
- Usual induction involves a stepwise process, whereas RSII prioritizes rapid cuffed endotracheal tube placement.
- RSII may include paralysis-inducing agents before laryngoscopy to prevent complications.
Indications for RSII:
- Patients with Full Stomach:
- Emergency surgery patients.
- Trauma patients.
- Non-adherence to preoperative fasting.
- Patients with Gastrointestinal Pathology:
- Gastroparesis, delayed gastric emptying.
- Small bowel or gastric outlet obstruction.
- GERD, esophageal stricture.
- Patients with Increased Intra-abdominal Pressure:
- Morbid obesity, ascites.
- Pregnancy after 20 Weeks (or earlier with reflux symptoms):
- Pregnant patients at risk of aspiration.
Complications:
- While RSI is an effective technique, it’s not without potential complications:
- Hypoxia: Due to apnea before intubation, patients can desaturate quickly. Proper preoxygenation and use of techniques like passive apneic oxygenation can help mitigate this risk.
- Hypotension: Induction agents and NMBAs can lead to decreased blood pressure, especially in patients with compromised cardiovascular function.
- Difficult Intubation: Even with RSI, difficult intubation can occur. If a patient’s airway proves challenging, alternative strategies should be employed.
- Esophageal Intubation: If the endotracheal tube is inadvertently placed in the esophagus, hypoxia and lung injury can result.
- Regurgitation and Aspiration: Although RSI aims to prevent aspiration, there’s still a risk, especially if the technique is not performed correctly.
- Bronchospasm: Induction agents and airway manipulation can trigger bronchospasm in susceptible patients.
- Laryngospasm: The use of NMBA can paralyze the vocal cords, making it difficult to pass the endotracheal tube.
- Cardiac Arrhythmias: Induction agents can affect cardiac rhythm, especially in patients with heart disease.
Contraindications to RSI:
- While RSI is effective in many scenarios, there are situations where it might not be appropriate:
- Known Difficult Airway: If the patient is known to have a difficult airway, RSI may not be the best choice due to potential complications during intubation.
- Full Stomach: RSI is designed to minimize the risk of aspiration, but if the patient has already vomited or has a full stomach, the risk might outweigh the benefits.
- Hemodynamic Instability: Patients with severe hemodynamic instability might not tolerate the medications used in RSI.
- Allergies or Sensitivities: Patients with known allergies or sensitivities to induction agents or NMBAs might need alternative approaches.
- Inadequate Preoxygenation: In cases where preoxygenation has not been properly performed, the risk of hypoxia during apnea induction is higher.
- Lack of Experience: RSI requires skill and experience. If the healthcare provider is not proficient in the technique, the risk of complications increases.
Gastroesophageal Reflux Disease (GERD) Consideration:
- Patients with GERD assessed individually for suitability for RSII.
- Factors include reflux symptoms, medication history, and endoscopic findings.
Preoperative Antacids:
- Patients on antacids should continue regimen before surgery.
- PPIs maximized with two doses pre-op.
- Famotidine or alternative PPI can be used.
Patients taking GLP-1 Receptor Agonists:
- GLP-1 agonists may delay gastric emptying.
- Guidelines suggest withholding for elective surgery or RSII if continued.
Effect of GLP-1 Agonists on Gastric Emptying:
- Mixed findings on impact of GLP-1 agonists on gastric emptying.
Gastric Ultrasound and Aspiration Risk:
- Gastric ultrasound for assessment if GLP-1 agonist use isn’t ceased.
- RSII advisable if GLP-1 agonist used until surgery.
Preparation for Anesthesia:
- Assistant trained in RSII and airway management essential.
- Comprehensive equipment, including airway devices, should be prepared.
Airway Evaluation:
- Assess airway difficulty and prior issues.
- Consider alternatives if airway is challenging
Equipment:
- Standard and alternative airway devices.
- Additional equipment for difficult airways.
Premedication:
- Anxiolytics, atropine, opioids, antacids, prokinetics, etc.
- Careful opioid dosing when combined with benzodiazepines.
Positioning:
- Sniffing position or ramped position for optimal access.
Preoxygenation:
- Preoxygenation with 100% oxygen.
- Nasal cannula for passive apneic oxygenation.
- Consider techniques like THRIVE.
Cricoid Pressure During RSII:
- Cricoid pressure’s contentious use during RSII.
- Benefits and concerns regarding application.
- Decision should weigh potential benefits against complications.
Choice of Medications for Rapid Sequence Intubation (RSII):
Induction Agents: The aim of RSII is rapid and safe endotracheal intubation after loss of consciousness. Induction agents should meet specific criteria, including rapid onset, minimal hemodynamic effects, optimal intubating conditions, and, in some cases, a short duration of action or reversibility. The goal is to achieve adequate depth of anesthesia and muscle paralysis to prevent complications during airway manipulation.
Propofol:
Induction Agents: The aim of RSII is rapid and safe endotracheal intubation after loss of consciousness. Induction agents should meet specific criteria, including rapid onset, minimal hemodynamic effects, optimal intubating conditions, and, in some cases, a short duration of action or reversibility. The goal is to achieve adequate depth of anesthesia and muscle paralysis to prevent complications during airway manipulation.
Propofol:
- Rapid onset (30 to 45 seconds).
- Suppresses airway reflexes and induces apnea.
- Short duration of action (5 to 10 minutes).
- Potential for hypotension due to dose-dependent vasodilation and decrease in cardiac contractility.
- Commonly used induction agent for RSII.
- Usual dose for RSII: 2 mg/kg, with adjustments for patients at risk of hypotension.
Etomidate:
- Fast onset and short duration of action.
- Does not cause vasodilation or myocardial depression.
- Preferred for patients at risk of hypotension.
- Induction dose: 0.2 to 0.4 mg/kg IV.
Ketamine:
- NMDA receptor antagonist.
- Increases sympathetic tone, potentially raising blood pressure, heart rate, and cardiac output.
- Suitable for patients at risk of hypotension.
- Induction dose: 1 to 2 mg/kg IV.
Barbiturates (Thiopental, Methohexital):
- Older induction agents.
- Thiopental is no longer available in the US.
- Rapid onset (less than 30 seconds) and short duration of action.
- Can cause hypotension and histamine release.
- Methohexital is an alternative with similar properties.
Opioids (Fentanyl, Remifentanil):
- Short-acting opioids can reduce sympathetic response to intubation.
- Remifentanil is an ultrashort-acting opioid.
- Used for profound suppression of airway reflexes.
Lidocaine:
- Administered to suppress cough reflex and sympathetic response to intubation.
- May prevent transient rise in intracranial pressure with laryngoscopy.
- Hypotension possible with higher doses.
Neuromuscular Blocking Agents (NMBAs):
- NMBAs are essential for optimal intubating conditions and to prevent complications during airway manipulation.
- Succinylcholine is commonly used for its rapid onset (30 to 60 seconds) and short duration of action (6 to 10 minutes).
- Nondepolarizing NMBAs (e.g., rocuronium, vecuronium, cisatracurium) can be used, but their onset is slower and duration longer compared to succinylcholine.
- Remifentanil can be used as an alternative to succinylcholine for intubation, with specific dosing protocols.
Important Considerations:
- The choice of medications should be individualized based on the patient’s condition, risk factors, and desired intubating conditions.
- Careful dosing and timing are crucial to achieve safe and effective RSII.
Emergence from Anesthesia and Airway Management for COVID-19:
- Aspiration risk during emergence.
- Orogastric tube, intubation maintenance, elevated head.
- Focus on patient care while minimizing COVID-19 spread.
