Incidence of transient hypoxia during pre-hospital rapid sequence intubation by anaesthesiologists

Pre-hospital tracheal intubation (TI) is an important but difficult procedure with the potential to produce hypoxaemia. The aim of this study was to determine the incidence of desaturation episodes during out-of-hospital rapid sequence induction (RSI) and TI by the medical team of a German Helicopter Emergency Medical Service (HEMS).

We performed a prospective study at HEMS 'CHRISTOPH 22'. TI was performed as RSI according to a standard protocol. Desaturation was defined as a reduction in SpO(2) below 90% or a reduction of more than 10% from baseline SpO(2) when initial values were less than 90%.

The RSI/TI manoeuvre was attempted in 150 patients [107 male (71.3%); median age 40 years (IQR 21-61); overall success rate 100%]. The incidence of desaturation episodes was 13.3% with a median duration of 50 sec. (IQR 30-92) and a median SpO(2) decrease of 24 ± 10%. Upon hospital admission, all patients had SpO(2) values ≥ 96%. In the desaturation group the duration of successful TI was significantly longer [median 85 sec. (IQR 60-119) vs. median 63 sec. (IQR 48-70); P < 0.01], and the number of patients with a baseline SpO(2) ≥ 90% was significantly lower (65.0% vs. 88.5%; P < 0.01). Among patients with difficult to manage airway, those with desaturation were significantly younger, and technical problems were significantly more frequent.

The incidence of episodes of desaturation during pre-hospital RSI/TI at HEMS Ulm is relatively low, and the duration of such episodes is short.