title: Latency and loss of pulse oximetry signal with the use of digital probes during prehospital rapid-sequence intubation.
abstract: BACKGROUND
  Prehospital personnel rely on timely and accurate pulse oximetry data when performing critical skills, such as rapid-sequence intubation (RSI). However, loss of signal may be a frequent occurrence in patients with poor peripheral perfusion. In addition, a delay or latency period in the timeliness of pulse oximetry data may exist with probes placed on the fingers.
  
  
  OBJECTIVE
  To define the incidence of pulse oximetry signal loss or a latent period during prehospital RSI.
  
  
  METHODS
  Patients with severe traumatic brain injury (TBI) (Glasgow Coma Scale score [GCS] 3-8) undergoing prehospital RSI by air medical crews were enrolled. Data from hand-held oximetry-capnometry units were analyzed for either the loss of a pulse oximetry tracing (≥ 30 seconds) during the RSI procedure or the presence of a latent period, defined by the saturation of peripheral oxygen (SpO(2)) nadir occurring after intubation in patients undergoing desaturation (SpO(2) ≤ 93%) during the procedure.
  
  
  RESULTS
  A total of 98 of 124 patients (79%, 95% confidence interval [CI] 71-85%) had pulse oximetry failure during critical points in the RSI procedure. In the 49 patients with a desaturation during RSI, a latent period was observed in 27 patients (55%, 95% CI 41-68%).
  
  
  CONCLUSIONS
  A high incidence of pulse oximetry failure was observed with the use of a digital pulse oximetry probe during prehospital RSI. In addition, a latent period appears to exist in the majority of patients undergoing desaturation.
authors.affiliation: Department of Emergency Medicine, UC San Diego, San Diego, California, USA. davismd@cox.net
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Davis
authors.forename: Steve
authors.initials: S
authors.lastname: Aguilar
authors.forename: Catherine
authors.initials: C
authors.lastname: Sonnleitner
authors.forename: Maya
authors.initials: M
authors.lastname: Cohen
authors.forename: Michelle
authors.initials: M
authors.lastname: Jennings
mesh_terms: D000328:Adult; D017732:Air Ambulances; D001785:Blood Gas Monitoring, Transcutaneous; D001930:Brain Injuries / Q000628:therapy*; D016001:Confidence Intervals; D004632:Emergency Medical Services / Q000379:methods*; D004634:Emergency Medical Technicians; D004868:Equipment Failure; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D015994:Incidence; D015601:Injury Severity Score; D007442:Intubation, Intratracheal / Q000295:instrumentation / Q000379:methods*; D008297:Male; D010092:Oximetry / Q000295:instrumentation / Q000379:methods*; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors