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Intraoperative modulation of alveolar macrophage function during isoflurane and propofol anesthesia
N Kotani1, H Hashimoto, D I Sessler
1Department of Anesthesiology, University of Hirosaki, Japan.
Background:
Alveolar macrophages are a critical part of the defense against pulmonary infection. Thus the authors determined time-dependent changes in alveolar macrophage functions in patients having surgery who were anesthetized with isoflurane or propofol.
Methods:
Patients anesthetized with propofol (n = 30) or isoflurane (n = 30) during orthopedic surgery were studied. Alveolar macrophages were harvested by bronchoalveolar lavage immediately, and 2, 4, and 6 h after induction anesthesia and at the end of surgery. The fraction of aggregated and nonviable macrophages was determined. Then phagocytosis was measured by ingestion of opsonized and unopsonized particles. Finally, microbicidal activity was determined as the ability of the macrophages to kill Listeria monocytogenes directly.
Results:
Demographic and morphometric characteristics of the patients given propofol and isoflurane were similar, as were their levels of pulmonary function and hemodynamic responses. The fraction of alveolar macrophages ingesting opsonized and unopsonized particles, and the number of particles ingested, decreased significantly over time, with the decrease slightly but significantly greater during isoflurane anesthesia. Microbicidal function decreased progressively during anesthesia and surgery, with the decrease almost twice as great during isoflurane compared with propofol anesthesia. The fraction of aggregated macrophages and recovered neutrophils increased over time in the patients given each anesthetic.
Conclusions:
Pulmonary immunologic function changed progressively during anesthesia and surgery. The data from this study suggest that pulmonary defenses are modulated by the type of anesthesia and by the duration of anesthesia and surgery.
Insights
Anesthesia type and duration impact lung immune cell function. Isoflurane anesthesia caused a greater decrease in alveolar macrophage activity and microbicidal function compared to propofol during surgery.
Area of Science:
- Immunology
- Anesthesiology
- Pulmonary Medicine
Background:
- Alveolar macrophages are crucial for lung defense against infection.
- Surgical anesthesia can potentially impair immune cell function.
- Understanding these effects is vital for patient recovery and outcomes.
Purpose of the Study:
- To investigate the time-dependent effects of isoflurane and propofol anesthesia on alveolar macrophage function.
- To compare the impact of these two anesthetic agents on pulmonary immune defenses during surgery.
Main Methods:
- Patients undergoing orthopedic surgery received either propofol or isoflurane anesthesia.
- Alveolar macrophages were collected via bronchoalveolar lavage at multiple time points.
- Macrophage phagocytosis, microbicidal activity, aggregation, and viability were assessed.
Main Results:
- Both anesthetics reduced macrophage phagocytic capacity and microbicidal activity over time.
- Isoflurane anesthesia led to a significantly greater impairment of these functions compared to propofol.
- The fraction of aggregated macrophages and neutrophils increased during anesthesia and surgery.
Conclusions:
- Pulmonary immune function undergoes progressive changes during anesthesia and surgery.
- The type of anesthesia (isoflurane vs. propofol) significantly modulates these changes.
- Anesthesia duration also plays a role in altering pulmonary defenses.