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The effect of oxygen concentration on atelectasis formation during induction of general anesthesia in children: A
Hyun Il Kim1, Ji Young Min2, Jeong-Rim Lee1
1Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul, Korea.
Insights
Lowering oxygen concentration during anesthesia induction in children reduces lung atelectasis. Specifically, 60% oxygen is more effective than 100% for preventing atelectasis immediately after induction, but this benefit is temporary.
Area of Science:
- Anesthesiology
- Pediatric Critical Care
Background:
- Lower oxygen concentrations during anesthesia induction in adults reduce atelectasis without increasing hypoxia.
- The effect of varying oxygen concentrations on pediatric patients undergoing anesthesia is not well-established.
Purpose of the Study:
- To investigate the impact of different oxygen concentrations (60%, 80%, 100%) during anesthetic induction on atelectasis formation in pediatric surgical patients.
Main Methods:
- Randomized controlled trial involving 54 pediatric patients undergoing elective lower abdominal surgery.
- Patients were assigned to receive sevoflurane with 60%, 80%, or 100% oxygen during induction.
- Lung ultrasound (LUS) was used to assess atelectasis after induction and at the end of surgery.
Main Results:
- Atelectasis was significantly lower after induction in the 60% oxygen group compared to the 100% group (p=0.015).
- No significant difference in atelectasis was observed between the 80% and 100% oxygen groups after induction.
- No significant differences in atelectasis were found among the groups at the end of surgery.
Conclusions:
- Lowering oxygen concentration to 60% during anesthetic induction reduces immediate post-induction atelectasis in children.
- 80% oxygen is insufficient to prevent atelectasis; 60% is recommended for immediate post-induction benefit.
- The protective effect of lower oxygen concentrations on atelectasis does not persist until the end of surgery.
Background:
In adults, the use of lower oxygen concentration during induction is associated with less atelectasis formation without an increase in incidence of hypoxia. However, it is unknown whether this remains true in the pediatric patients.
Methods:
Fifty-four pediatric patients who were scheduled to undergo elective lower abdominal surgery were randomized to one of three oxygenation groups: 100%, 80%, or 60% oxygen (in air). During anesthesia induction, patients were ventilated with sevoflurane in 100%, 80%, or 60% oxygen. Endotracheal intubation and mechanical ventilation were performed. Atelectasis was diagnosed using LUS, which was performed after anesthetic induction and at the end of surgery.
Results:
We assessed atelectasis after anesthetic induction and at the end of surgery. After anesthetic induction, the number of atelectatic lung regions was significantly different among the three groups (median [IQR], 2.0 [1.0-2.5], 2.0 [1.0-2.8], and 3.0 [2.0-3.0] in the 60%, 80%, and 100% oxygen groups, p = .033) and between the 60% and 100% groups (p = .015), but not between 80% and 100% groups (p = .074). However, no differences in the number of atelectatic lung regions were found among the three groups at the end of surgery (2.0 [1.3-3.8], 3.0 [1.8-3.0], and 4.0 [2.0-4.0] in the 60%, 80%, and 100% oxygen groups; p = .169).
Conclusion:
Lower oxygen concentration during anesthetic induction is associated with less atelectasis formation immediately after anesthetic induction in children. In addition, applying 80% oxygen instead of 100% oxygen is not enough to prevent atelectasis formation, and 60% oxygen should be applied to prevent atelectasis. However, this effect does not last until the end of surgery.
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