Delayed sequence Intubation (DSI) differs from rapid sequence induction/intubation (RSI) in that pre-medication is used to facilitate ventilation/preoxygenation prior to full induction/paralysis. That is, procedural sedation is used to preoxygenate the patient.
When is DSI Considered?
- Cannot preoxygenate the patient by any other means, leading to a high risk of hypoxemia and CV collapse otherwise.
- Significant agitation
- Procedures are required prior to intubation, such as NG tube placement fo stomach evacuation in the setting of GI bleed.
How to Perform DSI
1. Position the patient head-up at 30-45 degrees
2. Induction agent: ketamine 1-2 mg/kg IV as a slow IV push over 15-30 seconds to prevent apnea. Additional 0.5 mg/kg doses to achieve good level of complete dissociation if required.
3. Ensure the airway is patent.
4. Passively oxygenate the patient for at least 3 minutes
1. Nasal cannula at "flush" rate
2. NRB, BVM with PEEP valve
5. Administer Neuromuscular Blockade and wait at least 45-60 seconds:
1. Succinylcholine 1.5 mg/kg
2. Rocuronium 1.2-1.5 mg/kg
6. Intubate the patient
Evidence for DSI
- Mostly observational data (Delayed sequence intubation: a prospective observational study - PubMed) showed that preoxygenation was effectively achieved routinely with DSI, and that DSI was not associated with complications.
- Small N=200 RCT published in 2023 (Peri-Intubation Hypoxia After Delayed Versus Rapid Sequence Intubation in Critically Injured Patients on Arrival to Trauma Triage: A Randomized Controlled Trial - PubMed) looking at DSI vs RSI in trauma patients showed that DSI was associated with lower rate of per-intubation hypoxia, higher first-pass success rate, without incident hemodynamic instability or airway-related adverse events.
References
- Delayed sequence [intubation](Intubation.md) (DSI) • LITFL • CCC Airway
- Delayed Sequence [Intubation](Intubation.md): Basics for Residents EMRA