In this episode, I’ll discuss an article about drug order in rapid sequence intubation.
Article
Drug Order in Rapid Sequence Intubation
Lead author: Brian Driver
Published in Academic Emergency Medicine March 2019
Background
There is continued debate over the optimal order of drug administration in rapid sequence intubation (RSI) scenarios. A sedative first approach may minimize the risk of the patient experiencing a brief awake-but-paralyzed situation, while a paralytic first approach may minimize the risk of anoxia by allowing for an earlier successful intubation.
The authors of this study sought to determine if RSI drug order was associated with the time elapsed from administration of the first RSI drug to the end of a successful first intubation attempt.
Methods
The study was a planned secondary analysis of a randomized trial of adult ED patients undergoing emergency orotracheal intubation. In the primary analysis, the study concluded that there was a higher first‐attempt success with bougie use compared to a traditional tracheal tube plus stylet.
The study did not proscribe the drug choice, dose, and the order of sedative and neuromuscular blocking agent. The authors analyzed trial patients who received both a sedative and a neuromuscular blocking agent within 30 seconds of each other who were intubated successfully on the first attempt.
The primary outcome was the time elapsed from complete administration of the first RSI drug to the end of the first intubation attempt. Because the trial only looked at first-attempt successes, the end of the first attempt also served as a surrogate outcome for apnea time.
Results
Of 757 original trial patients, 74% had a first pass success and were included in this analysis. Of these patients, 27% received the sedative first and 73% received the paralytic first. The study found that the group that experienced the paralytic agent first had a statistically significant reduction in time from RSI administration to the end of intubation attempt of 6 seconds.
Conclusion
The authors concluded:
Administration of either the neuromuscular blocking or the sedative agent first are both acceptable. Administering the neuromuscular blocking agent first may result in modestly faster time to intubation. For now, it is reasonable for physicians to continue performing RSI in the way they are most comfortable with. If future research determines that the order of medication administration is not associated with awareness of neuromuscular blockade, administration of the neuromuscular blocking agent first may be a logical default administration method to attempt to minimize apnea time during intubation.
Discussion
It is critical to maximize the “safe apnea time” for the patient during RSI. This is the time the provider has to place the airway after the patient stops breathing and before their O2 saturation drops to dangerous levels. This may be 8 minutes for a healthy adult, or less than 4 minutes for a critically ill or obese adult.
The difference in time to intubation of 6 seconds found in this study is unlikely to have a clinically significant impact on the risk of anoxic injury for patients undergoing RSI.
However, in an individual patient with a low predicted safe apnea time such as a critically ill obese patient, every second of safe apnea time could be critical to ensuring a positive outcome from intubation.
Previously in episode 186 I looked at this scenario when choosing to give ketamine first or rocuronium first for RSI.
I simulated the onset times for ketamine and rocuronium 5000 times using Microsoft Excel to create random values with a normal distribution around each mean onset time.
I assumed that each medication would be given sequentially and that the administration would take 20 seconds for each medication. I then calculated the sedation lag time and anesthetic awareness time for each simulated patient receiving rocuronium first and again receiving ketamine first.
When ketamine was given first, the average sedation lag time was 49 seconds. In a patient with a 2 minute safe apnea time, this represents 41% of the safe apnea time used up waiting for medications to work.
One out of 5000 simulated patients had a 3.9 second period of anesthetic awareness. However, this simulated value had rocuronium taking effect at 4 seconds after administration.
When rocuronium was given first, the sedation lag time was 15.1 seconds in simulated patients without an episode of anesthetic awareness. In a patient with a 2 minute safe apnea time, this represents 13% of the safe apnea time used up waiting for medications to work.
2.2% of simulated patients had an anesthetic awareness time greater than 20 seconds in the analysis.
I would expect the results would be very similar when exchanging the induction agent for etomidate or propofol or the paralytic for succinylcholine.
The difference between groups in this study supports the author’s conclusion that physicians should administer RSI drugs in the order they are most comfortable doing so.
My preference in most scenarios would be to choose to administer the sedative agent first, however the shorter the predicted safe apnea time for a patient the more reasonable I think it is to administer the paralytic first.
You can access a template for conducting your own monte carlo analysis in my free download area by going to pharmacyjoe.com/free, it is number 12 on the list.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
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