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Study of the safe threshold of apneic period in children during anesthesia induction
1Department of Anesthesiology, Plastic Surgery Hospital, Chinese Academy of Medical Sciences, Beijing, People's Republic of China.
Insights
A safe threshold of 95% oxygen saturation (SpO2) is appropriate during pediatric anesthesia induction. Younger children face higher hypoxemia risks during apnea, with time to reach 95% SpO2 correlating to age, weight, and height.
Area of Science:
- Pediatric Anesthesiology
- Respiratory Physiology
- Clinical Outcomes
Background:
- Anesthetic induction in children requires careful monitoring of oxygen saturation.
- Rapid sequence induction involves a period of apnea, increasing hypoxemia risk.
- Preoxygenation duration is critical for maintaining oxygen levels during apnea.
Purpose of the Study:
- To investigate changes in arterial oxygen saturation (SpO2) during apnea in children.
- To determine the appropriateness of a 95% SpO2 threshold for apneic periods.
- To evaluate factors influencing the time to reach 95% SpO2 during apnea.
Main Methods:
- A randomized clinical study involving 152 children (3 months to 12 years).
- Patients were divided into age groups and randomly assigned to ventilation triggers at 90% or 95% SpO2.
- Anesthesia was induced using standard agents, followed by apnea and monitored SpO2 levels.
Main Results:
- Younger children exhibited greater susceptibility to hypoxemia during apnea.
- Significant differences in time to reach 90% and 95% SpO2 were observed across age groups.
- Apnea duration to 95% SpO2 correlated with patient age, body weight, and height.
Conclusions:
- A 95% SpO2 threshold is appropriate for apneic periods during pediatric anesthesia induction.
- Younger children require closer monitoring due to increased hypoxemia risk.
- Patient demographics (age, weight, height) influence the time to desaturation.
Study Objectives:
(1) To investigate changes in arterial oxygen saturation via pulse oximeter (SpO2) during apnea and after reinstitution of manual ventilation at SpO2 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 SpO2 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 SpO2 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 1, 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 micrograms/kg and suxamethonium 1.5 mg/kg. Patients were manually ventilated when SpO2 decreased to 90% in Subgroups A and 95% in Subgroups B, respectively, during apnea.
Measurements And Main Results:
SpO2 was measured continuously with a Datex pulse oximeter applied to the right index finger. During apnea, the times for SpO2 to decrease to 09% (T99) and 95% (T99) in all children, and 90% (T90) in Subgroups A were recorded. The time for SpO2 to decrease from 95% to 90% (T95-90) in Subgroups A was also measured. After reinstitution of manual ventilation, the time when SpO2 continued to decrease (T1) and the time from the end of apnea to recovery of SpO2 baseline (T2) were determined. In addition, the lowest value of SpO2 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 T99, T95, T90, and T95-90 between the three age groups T1 and T2 were significantly longer in Group 3 than in Groups 1 and 2. There were significant differences in the lowest values of SpO2 following apnea among the three Subgroups A and between Subgroups A and B of each age group. During apnea, heart rate decreased gradually as SpO2 decreased, showing a significant decrease at SpO2 of 95%. Bradycardia was found in three children in Subgroups A. The apnea time to SpO2 of 95% correlated well with age, weight, and height by linear regression analysis.
Conclusions:
The safe threshold of an apneic period setting to an SpO2 of 95% was appropriate in children during anesthesia induction. Despite the same duration of preoxygenation, younger children were more susceptible than elder ones to the risk of hypoxemia during apnea. The apnea time to SpO2 of 95% correlated with age, body weight, and height using linear regression analysis.