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Published on: December 5, 2025
Rate of decline in oxygen saturation at various pulse oximetry values with prehospital rapid sequence intubation
Daniel P Davis1, James Q Hwang, James V Dunford
1Department of Emergency Medicine, University of California San Diego, San Diego, California 92103-8676, USA. davismd@cox.net
Background:
A high incidence of desaturations has been observed during prehospital rapid sequence intubation (RSI). The rate of decline in oxygen saturation (SpO2) at various pulse oximetry values has not been defined with emergency RSI. Objective. To define the rate of SpO2 decline at various pulse oximetry values and identify a threshold below which active BVM should be performed during prehospital RSI.
Methods:
Traumatic brain injury (TBI) patients undergoing RSI by prehospital providers were included in this analysis. The time period from the highest to the lowest preintubation SpO2 value was selected for review. The mean rate of SpO2 decline was calculated for each SpO2 value and then used to define a theoretical SpO2 desaturation curve. The rate of desaturation to hypoxemia (SpO2
Results:
A total of 684 SpO2 values from 87 patients were included. Lower SpO2 values were associated with a faster rate of SpO2 decline, with an inflection point occurring at 93%. The rate of desaturation to hypoxemia with intubation attempts initiated with SpO2
Conclusions:
The rate of SpO2 decline increases as SpO2 decreases, with an inflection point occurring around 93%. Intubation attempts below this value are almost always associated with subsequent desaturation, suggesting that BVM should be used prior to laryngoscopy in these patients.
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