Study of the safe threshold of apneic period in children during anesthesia induction

• Published in: Journal of clinical anesthesia 1996-11, Vol.8 (7), p.568-574
• Main Authors: Xue, Fu S., Luo, Lai K., Tong, Si Y., Liao, Xu, Deng, Xiao M., An, Gang
• Format: Article
• Language: English
• Subjects: Age Factors; Anesthesia, Intravenous; Anesthesia, pediatric; Anesthetics, Intravenous - administration & dosage; apnea; Apnea - blood; Apnea - physiopathology; Body Height; Body Weight; Bradycardia - etiology; Child; Child, Preschool; Disease Susceptibility; Elective Surgical Procedures; Fentanyl - administration & dosage; Heart Rate; Humans; Hypoxia - etiology; Infant; Linear Models; Neuromuscular Depolarizing Agents - administration & dosage; Oximetry; Oxygen - administration & dosage; Oxygen - blood; oxygen saturation; pulse oximetry; Respiration, Artificial; Risk Factors; safe threshold; Safety; Succinylcholine - administration & dosage; Surgery, Plastic; Thiopental - administration & dosage; Time Factors
• ISSN: 0952-8180; 1873-4529
• DOI: 10.1016/S0952-8180(96)00138-9

Study Objectives: (1) To investigate changes in arterial oxygen saturation via pulse oximeter (SpO 2) during apnea and after reinstitution of manual ventilation at SpO 2 of 95% or 90% following rapid sequence induction of anesthesia in children after 2-minute preoxygenation; (2) to determine whether the setting of a safe threshold of apneic period to an SpO 2 of 95% is appropriate in children during anesthetic induction; and (3) to evaluate the influences of age, body weight, and height on the time from the start of apnea to SpO 2 of 95%. Design: A clinical study of random design and comparison among groups. Setting: Operating room of a plastic surgery hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College. Patients: 152 infants and children, ASA physical status I, aged 3 months to 12 years, scheduled for elective plastic surgery. Interventions: Patients were divided into three age groups: Group 1-infants 3 months to 1 year (n = 39); Group 2-children 1 to 3 years (n = 41); and Group 3-children 3 to 12 years (n = 72). Patients in each age group were randomly allocated again to Subgroups A and B. After a 2-minute preoxygenation, anesthesia was induced with thiopental 5 mg/kg, fentanyl 5 μg/kg, and suxamethonium 1.5 mg/kg. Patients were manually ventilated when SpO 2 decreased to 90% in Subgroups A and 95% in Subgroups B, respectively, during apnea. Measurements and Main Results: SpO 2 was measured continuously with a Datex pulse oximeter applied to the right index finger. During apnea, the times for SpO 2 to decrease to 99% (T 99) and 95% (T 95) in all children, and 90% (T 90) in Subgroups A were recorded. The time for SpO 2 to decrease from 95% to 90% (T 95 − 90) in Subgroups A was also measured. After reinstitution of manual ventilation, the time when SpO 2 continued to decrease (T 1) and the time from the end of apnea to recovery of SpO 2 baseline (T 2) were determined. In addition, the lowest value of SpO 2 after apnea was also recorded. The results showed that younger children were more susceptible than older children to the risk of hypoxemia during apnea. There were significant differences in T 99, T 95, T 90, and T 95 − 90 between the three age groups. T 1 and T 2 were significantly longer in Group 3 than in Groups 1 and 2. There were significant differences in the lowest values of SpO 2 following apnea among the three Subgroups A and between Subgroups A and B of each age group. During apnea, heart rate decreased graduall