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Supplemental intraoperative oxygen augments antimicrobial and proinflammatory responses of alveolar macrophages
N Kotani1, H Hashimoto, D I Sessler
1Department of Anesthesiology, University of Hirosaki, Japan. nao@cc.hirosaki-u.ac.jp
Background:
The first goal was to test the hypothesis that 100% inspired oxygen maintained for approximately 8 h intraoperatively is not associated with impaired pulmonary oxygenation. The authors also tested the hypothesis that intraoperative inhalation of 100% oxygen augments proinflammatory and antimicrobial responses of alveolar macrophages during anesthesia and surgery.
Methods:
The authors studied patients administered 100% oxygen (n = 30) and 30% oxygen (n = 30) during propofol-fentanyl general anesthesia. Alveolar macrophages were harvested by bronchoalveolar lavage immediately, 2, 4, and 6 h after induction of anesthesia, and at the end of surgery. The authors measured "opsonized" and "unopsonized" phagocytosis and microbicidal activity. RNA was extracted from harvested cells and cDNA was synthesized. The expression of interleukin(IL)-1beta, IL-6, IL-8, interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) was measured by semiquantitative polymerase chain reaction.
Results:
Gene expression of all proinflammatory cytokines except IL-6 increased fourfold to 20-fold over time in both groups. However, expression of TNF-alpha and IL-8, IFN-gamma, and IL-6 and IL-1beta was 2-20 times greater in patients administered 100% than in those administered 30% oxygen. Unopsonized and opsonized phagocytosis and microbicidal activity decreased progressively, with the decreases being nearly twice as great during inhalation of 30% oxygen versus 100% oxygen.
Conclusion:
Inhalation of 100% oxygen improved intraoperative decreases in phagocytic and microbicidal activity possibly because expression of proinflammatory cytokines was augmented. These data therefore suggest that intraoperative inhalation of 100% oxygen augments antimicrobial and proinflammatory responses in alveolar macrophages during anesthesia and surgery.
Insights
Intraoperative 100% oxygen improved immune cell function and boosted anti-inflammatory responses in patients during surgery. This suggests higher oxygen levels enhance the body's defense mechanisms during anesthesia.
Area of Science:
- Anesthesiology
- Immunology
- Pulmonary Medicine
Background:
- Investigating the effects of intraoperative 100% oxygen on pulmonary oxygenation and immune responses.
- Testing the hypothesis that prolonged 100% oxygen exposure does not impair lung function.
- Examining the impact of 100% oxygen on alveolar macrophage proinflammatory and antimicrobial activities.
Purpose of the Study:
- To evaluate if 100% inspired oxygen during 8-hour surgery impairs pulmonary oxygenation.
- To determine if intraoperative 100% oxygen augments proinflammatory and antimicrobial responses of alveolar macrophages.
Main Methods:
- Patients received either 100% or 30% oxygen during propofol-fentanyl anesthesia.
- Alveolar macrophages were collected via bronchoalveolar lavage at multiple time points.
- Phagocytosis, microbicidal activity, and gene expression of cytokines (IL-1beta, IL-6, IL-8, IFN-gamma, TNF-alpha) were measured.
Main Results:
- Gene expression for most proinflammatory cytokines increased in both groups over time.
- 100% oxygen group showed 2-20 times greater expression of TNF-alpha, IL-8, IFN-gamma, IL-6, and IL-1beta compared to 30% oxygen.
- Phagocytic and microbicidal activity decreased in both groups, but less significantly with 100% oxygen.
Conclusions:
- Intraoperative 100% oxygen may improve phagocytic and microbicidal activity by augmenting proinflammatory cytokine expression.
- Findings suggest that 100% oxygen enhances antimicrobial and proinflammatory responses in alveolar macrophages during surgery.