Duration of apnea in anesthetized infants and children required for desaturation of hemoglobin to 95%. The influence of upper respiratory infection

Anesthesiology. 1992 Dec;77(6):1105-7. doi: 10.1097/00000542-199212000-00010.


Sixty-one patients ASA physical status 1-2 aged 1 month to 12 years undergoing elective surgery were included in the study. Anesthesia was induced via a mask with sevoflurane up to 5% and 66% nitrous oxide in oxygen. After paralysis with vecuronium (0.12 mg/kg iv), the trachea was intubated and the lungs were ventilated manually with 3% sevoflurane in oxygen until the end-tidal nitrous oxide decreased to less than 5%. Apnea was started by disconnecting the breathing circuit from the endotracheal tube. The time from the start of apnea to Spo2 of 95% was measured. Manual ventilation was reinstituted when Spo2 decreased to 95% and another set of vital signs was recorded. Twenty of 61 patients had symptoms of upper respiratory infection. The time to Spo2 of 95% correlated well with height, age, and body weight both by linear and non-linear regression analyses. The patients with symptomatic upper respiratory infection required less time for Spo2 to decrease to 95% compared to the asymptomatic children. We conclude that younger children require less time for Spo2 to decrease to 95%. The presence of upper respiratory infection is an additional factor increasing the susceptibility of small children to hypoxemia.

MeSH terms

  • Anesthesia, Inhalation*
  • Child
  • Child, Preschool
  • Ethers
  • Humans
  • Infant
  • Methyl Ethers*
  • Nitrous Oxide
  • Oxygen
  • Oxyhemoglobins / metabolism*
  • Respiration / physiology*
  • Respiration Disorders / physiopathology*
  • Sevoflurane
  • Surgical Procedures, Operative
  • Time Factors


  • Ethers
  • Methyl Ethers
  • Oxyhemoglobins
  • Sevoflurane
  • Nitrous Oxide
  • Oxygen