Desaturation during Emergency Department Rapid Sequence Intubation.
Bodily JB, Webb HR, Weiss SJ, Braude DA. Incidence and Duration of Continuously Measured Oxygen Desaturation During Emergency Department Intubation. Annals of Emergency Medicine. 2016 Mar;67(3):389-95.
Hypoxia is a recognized adverse event of endotracheal intubation (ETI) with potentially devastating consequences. Prior to this study, the reported rates of desaturation ranged from 0.2 to 19.2 percent whem performed by Emergency Medicine (EM) physicians in the Emergency Department (ED). Previous studies largely relied on clinician reported desaturation events or exclusion of patients with certain complications that could result in hypoxia (e.g. esophageal intubation), which both could lead to an under-reporting of desaturation.
This was a retrospective observational study performed in a southwest urban academic ED with a level I trauma center. Data was obtained from all rapid sequence intubations that occurred over a 10-month period, which were identified from Pyxis records of a paralytic having been administered. Continuous pulse oximetry (SpO2) recordings were assessed for initial SpO2, nadir, and duration of desaturation. Physician records were assessed for number of intubation attempts, patient age & sex, intubator and level of training, and drugs used. Nursing records were used to determine start and completion times of the procedure. Desaturation was defined as a decrease of SpO2 to <90% if starting SpO2 >90% or any decrease in SpO2 if initial SpO2 <90%. The change in SpO2 was calculated, the nadir identified, and the duration of desaturation was measured.
As they sought to identify factors associated with desaturation, they produced a multivariable logistic regression model with desaturation as the dependent variable. Due to uncertainty regarding number of desaturation events, their a priori plan was to include pre-intubation SpO2 of <93%, number of ETI attempts and intubation time as primary variables.
Initially, 265 patients were identified, but 99 were excluded due to failure of monitor to record (53 patients), inadequate documentation in medical or nursing record (26 patients), poor SpO2 waveform (17 patients), and three intubations performed by non-EM physicians.
The majority of intubations were performed by PGY-2s (51%) followed by PGY-3, Pgy-1, and lastly an attending. Patients were nearly 3 quarters male with a median age of 51. Type of patient was broken down by medical (62%), trauma (18%), neurologic (17%), and resuscitated cardiac arrest (3%).
Of the 166 patients for which data was available, desaturation occurred in 59 (36%). Of those 59, 40 initially had an SpO2 >90%. The median duration of desaturation was 1 minute 20 seconds with a range of 55 seconds to 2 minutes 35 seconds. The median change in SpO2 was -2.2, but ranged from an increase of 15.5 to a decrease of 58. Of patients w/ a starting SpO2 > 93, the median nadir was 95%, and those with a starting SpO2 <90, the median drop was to 84%.
Ultimately the following were found to be associated with desaturation:
SpO2 <93% at start (adjusted odds ratio: 5.1)
Intubation time >3 minutes (adjusted odds ratio: 2.7)
>1 ETI attempt (adjusted odds ratio: 3.4)
Desaturation during intubation in an academic Emergency Department is common and prolonged. It is associated with starting SpO2 <93%, more than one attempt, and total procedure time >3 minutes. How this would change in the non-academic setting is unknown. As apneic oxygenation has become popular, it is unknown how or if the results of this would have changed with its use. Be that as it may, this reinforces the importance of optimizing the setting of intubation to ensure not only good pre-oxygenation but first-pass success.