Apnoeic oxygenation for emergency anaesthesia of pre-hospital trauma patients

Abstract

Background Efficient and timely airway management is universally recognised as a priority for major trauma patients, a proportion of whom require emergency intubation in the pre-hospital setting. Adverse events occur more commonly in emergency airway management, and hypoxia is relatively frequent. The aim of this study was to establish whether passive apnoeic oxygenation was effective in reducing the incidence of desaturation during pre-hospital emergency anaesthesia. Methods A prospective before-after study was performed to compare patients receiving standard care and those receiving additional oxygen via nasal prongs. The primary endpoint was median oxygen saturation in the peri-rapid sequence induction period, (2 minutes pre-intubation to 2 minutes post-intubation) for all patients. Secondary endpoints included the incidence of hypoxia in predetermined subgroups. Results Of 725 patients included; 188 patients received standard treatment and 537 received the intervention. The overall incidence of hypoxia (first recorded SpO2 < 90%) was 16.7%; 10.9% had SpO2 < 85%. 98/725 patients (13.5%) were hypoxic post-intubation (final SpO2 < 90% 10 minutes post-intubation). Median SpO2 was 100% vs. 99% for the standard vs. intervention group. There was a statistically significant benefit from apnoeic oxygenation in reducing the frequency of peri-intubation hypoxia (SpO2 < =90%) for patients with initial SpO2 > 95%, p = 0.0001. The other significant benefit was observed in the recovery phase for patients with severe hypoxia prior to intubation. Conclusion Apnoeic oxygenation did not influence peri-intubation oxygen saturations, but it did reduce the frequency and duration of hypoxia in the post-intubation period. Given that apnoeic oxygenation is a simple low-cost intervention with a low complication rate, and that hypoxia can be detrimental to outcome, application of nasal cannulas during the drug-induced phase of emergency intubation may benefit a subset of patients undergoing emergency anaesthesia.

Rapid sequence induction: where did the consensus go?

“…Where the airway is patent it would be fully expected to increase the time to desaturation and this has been confirmed in the pre-hospital environment [ 62 ]. Unfortunately, clear benefit has not been demonstrated in more recent studies [ 63 , 64 ]. On the basis that apnoeic oxygenation is likely to delay the onset of hypoxaemia in some patient groups and is easy to deliver, it is likely to continue to be used in emergency practice.…”

The efficacy of apneic oxygenation to prevent hypoxemia during rapid sequence intubation in trauma patients

“…The use of apneic oxygenation in the setting of high-risk airway situations has been recommended by some experts, but there is a paucity of studies evaluating the efficacy of apneic oxygenation in preventing hypoxemia in trauma patients. We will discuss the most recent findings of studies, which suggest that apneic oxygenation may be beneficial in trauma RSIs [8 ▪ ,11 ▪▪ ,12–15].…”

“…Five studies evaluated the effect of apneic oxygenation on peri-intubation hypoxemia, which was defined as SpO 2 less than 90% [2 ▪ ,11 ▪▪ ,12–14,16] (see Table 1 for study comparisons). Three of the studies stated that patients receiving apneic oxygenation had decreased rates of hypoxemia in the peri-intubation period [11 ▪▪ ,14,15].…”

“…Five studies evaluated the effect of apneic oxygenation on peri-intubation hypoxemia, which was defined as SpO 2 less than 90% [2 ▪ ,11 ▪▪ ,12–14,16] (see Table 1 for study comparisons). Three of the studies stated that patients receiving apneic oxygenation had decreased rates of hypoxemia in the peri-intubation period [11 ▪▪ ,14,15]. Sakles et al [14] evaluated patients undergoing RSI for intracranial hemorrhage (ICH) and reported a seven-fold decrease in the odds of hypoxemia for patients receiving apneic oxygenation.…”

“…Three studies evaluated the occurrence of severe hypoxemia (defined as SpO 2 <85%, SpO 2 <80%, SpO 2 <70%) [11 ▪▪ ,12,14]. Crewdson et al [11 ▪▪ ] used SpO 2 less than 85% as a measure of severe hypoxemia and reported no difference between apneic oxygenation and the control group.…”