Using DSI to Prevent RSI from Becoming RSD (Rapidly Sequenced Death)
By Jeffrey L. Jarvis, MD
RSI (Rapid Sequence Intubation) is a common process used by EMS agencies across the nation to perform endotracheal intubation. It involves administering a sedative agent (often ketamine, etomidate, or Versed) and a neuromuscular blocking agent (succinylcholine or rocuronium) in rapid succession followed closely thereafter with intubation. While much attention has been placed on maximizing the process of correctly inserting the ET tube into the trachea, little has been paid to the physiological effects of this process on the patient.
Recently, several people have begun discussing the dangers of this process. Often, EMS is intubating patients who are hypoxic with the belief that doing so rapidly is the only way to improve their oxygen saturations. Unfortunately, it isn’t commonly recognized that intubating a patient with even low-normal oxygen saturations (90-93%) very often lead to critical desaturations that can even lead to cardiac arrest. The intent behind a safe intubation is to provide high concentration oxygen for at least three minutes to allow a spontaneously breathing patient to replace the nitrogen in their lungs with oxygen, thus creating a reservoir of oxygen they can draw on during the intubation process. This ‘buys’ the paramedic time to safely perform the skill of intubation. Sadly, hypoxic patients often do not allow the paramedic to provide this oxygen effectively for the needed three minutes because of their anxiety or agitation.
Delayed Sequence Intubation is a phrase coined by Dr. Scott Weingart.1,2 As described in these papers, it is essentially procedural sedation using ketamine where the procedure is pre-oxygenation. Ketamine is a unique dissociative anesthetic which induces general anesthesia while preserving respiratory drive and airway reflexes. By giving hypoxic, agitated patients ketamine (typically at a dose of 2 mg/kg IV), the paramedic can provide sufficient sedation to pre-oxygenate the patient for three minutes, enough time to fully de-nitrogenate the lungs and maximize the pre-intubation oxygen saturation. After this delay, the neuromuscular agent is given which will induce paralysis, removing muscle tone that makes intubation difficult, thus maximizing the conditions for a first pass intubation success.
This process was implemented at Williamson County EMS this year. In a retrospective analysis undertaken as part of a normal quality improvement effort, several problems were identified, including frequent hypoxic episodes and patient decompensations. As a result, DSI was implemented. The results were stunning. Using RSI, the average low SpO2 during intubation was 78%. With DSI it was 98%. Over 84% of all RSI intubations experienced a moderate hypoxic episode (<90%) and 85% had severe hypoxia (<70%). Using DSI, this number was 0. There were NO hypoxic episodes.
For programs that perform RSI, I strongly recommend looking into both the frequency of peri-intubation hypoxia and the adoption of a DSI protocol to prevent it. For more information, please contact Dr. Jeff Jarvis on Twitter @DrJeffJarvis or via email at firstname.lastname@example.org. Videos further describing the science behind this process, as well as the specifics of the procedure, can be found on the Williamson County EMS YouTube channel.
- Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012;59(3):165-175 e161.
- Weingart SD, Trueger NS, Wong N, Scofi J, Singh N, Rudolph SS. Delayed sequence intubation: a prospective observational study. Ann Emerg Med. 2015;65(4):349-355.
The content of this article was taken from Dr. Jarvis’ presentation at EMS EVOLUTION 2016 in June 2016