Rapid Sequence Intubation (RSI)
Rapid sequence intubation (RSI) is a protocol for endotracheal intubation intended to reduce aspiration risk during induction by minimizing time spent without airway protection. [1] A commonly taught “classic” RSI approach includes cricoid pressure application and avoidance of positive-pressure ventilation after induction until the endotracheal tube is secured. [1]
Modified Rapid Sequence Intubation (Modified RSI)
“Modified RSI” is a nonstandard term that is used inconsistently across settings and authors. [2] A frequently cited description of “modified RSI” includes oxygen administration before induction, use of cricoid pressure, and an attempt to ventilate the patient before the airway is secured. [1]
Core Procedural Differences
- Ventilation strategy before securing the airway: Modified RSI includes an attempt to ventilate the patient (positive-pressure ventilation or mask ventilation) before the endotracheal tube is secured. [1]
- Cricoid pressure use: Modified RSI definitions in practice often still include cricoid pressure rather than omitting it. [1]
- Terminology consistency: RSI is used as a more standard term, while “modified RSI” varies by institution and clinician practice. [2]
Practical Implications of the Differences
Positive-pressure ventilation attempts during modified RSI may help prevent or treat hypoxemia during the interval before intubation success. [1] Positive-pressure ventilation before airway control may be viewed as increasing theoretical risk of gastric insufflation and regurgitation-related aspiration compared with approaches that avoid positive-pressure ventilation after induction. [3]
Common Points of Confusion
- “Modified RSI” does not have a single universally accepted definition. [2]
- The term is sometimes discouraged because it can obscure which specific changes have been made relative to a reference RSI approach. [4]
Summary of What to Compare in Documentation
The specific elements that should be compared between RSI and any “modified RSI” protocol are the following: [1], [2]
- Whether oxygenation is provided during the pre-induction and peri-induction period. [1]
- Whether cricoid pressure is used. [1]
- Whether positive-pressure ventilation occurs after induction and before endotracheal tube placement. [1]
- Which neuromuscular-blocking agent and drug timing are used. [2]
- Whether a supraglottic airway or other airway rescue step is planned during failed intubation. [2]