Preoxygenation in children: for how long?
Although preoxygenation has been extensively studied, to our knowledge this is the first study addressing its optimal length in children, who form a high risk group for developing hypoxaemia during induction of anaesthesia. Recommended preoxygenation times in children range between 1 and 4 min, but whether one of these times maintains arterial oxygen saturation (Sao2) at an adequate level for a longer time period is unknown. This study was performed on 11 healthy children, randomly distributed into either Group 1 (1 min of preoxygenation, n = 6) or Group 2 (3 min of preoxygenation, n = 5). Sao2 was measured by pulse oximetry. While the patients were breathing room air, Sao2 was similar in both groups (97%) and rose to 100% after preoxygenation in all patients. After intravenous induction of anaesthesia and muscle relaxation, all patients became apnoeic. The time taken for the Sao2 to decrease to 90% was measured. In Group 1 this occurred in 91 s, whereas Group 2 required 144 s. Thus, a 3-min rather than a 1-min period of preoxygenation would appear to maintain Sao2 at a safe level for a longer time in children.
Videira
R L
RL
Division of Anaesthesia, Hospital das Clinicas Sao Paulo University School of Medicine, Brazil.
Neto
P P
PP
do Amaral
R V
RV
Freeman
J A
JA
D002648:Child; D002675:Child, Preschool; D006801:Humans; D010100:Oxygen / Q000008:administration & dosage* / Q000097:blood; D010372:Pediatrics; D013997:Time Factors
D010100:Oxygen