Oxygen prevented hypoxia. Yep.
Why wouldn’t you give oxygen prophylactically to someone undergoing procedural sedation? One argument is that this will delay the detection of respiratory depression since a pre-oxygenated patient can be hyponoeic/apnoeic for longer prior to desaturation. This is not an issue for those of us who use non-invasive capnography during sedation.
In this randomized trial of oxygen vs air during ED propofol procedural sedation there was less hypoxia when high-flow supplemental oxygen was added. The authors made the following observations:
- There was no difference between groups in the incidence of respiratory depression, confirming previous research that supplemental oxygen does not exacerbate respiratory depression
- 5 patients in the compressed air group developed hypoxia without preceding respiratory depression, so capnography cannot be completely relied on in this setting.
“…assuming that capnography is in place to monitor ventilatory function, our results strongly support the routine use of high-flow oxygen during ED propofol sedation”
STUDY OBJECTIVE: We determine whether high-flow oxygen reduces the incidence of hypoxia by 20% in adults receiving propofol for emergency department (ED) sedation compared with room air.
METHODS: We randomized adults to receive 100% oxygen or compressed air at 15 L/minute by nonrebreather mask for 5 minutes before and during propofol procedural sedation. We administered 1.0 mg/kg of propofol, followed by 0.5 mg/kg boluses until the patient was adequately sedated. Physicians and patients were blinded to the gas used. Hypoxia was defined a priori as an oxygen saturation less than 93%; respiratory depression was defined as an end tidal CO(2) greater than 50 mm Hg, a 10% absolute change from baseline, or loss of waveform.
RESULTS: We noted significantly less hypoxia in the 59 patients receiving high-flow oxygen compared with the 58 receiving compressed air (19% versus 41%; P=.007; difference 23%; 95% confidence interval 6% to 38%). Respiratory depression was similar between groups (51% versus 48%; difference 2%; 95% confidence interval -15% to 22%). We observed 2 adverse events in the high-flow group (1 hypotension, 1 bradycardia) and 2 in the compressed air group (1 assisted ventilation, 1 hypotension).
CONCLUSION: High-flow oxygen reduces the frequency of hypoxia during ED propofol sedation in adults.
The Utility of High-Flow Oxygen During Emergency Department Procedural Sedation and Analgesia With Propofol: A Randomized, Controlled Trial
Ann Emerg Med. 2011 Oct;58(4):360-364