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[Intraoperative calorimetry in aortic bifurcation reconstruction]
1Klinik für Anästhesie und Allgemeine Intensivmedizin, Universität Innsbruck.
Der Anaesthesist
|August 1, 1995
Summary
Indirect calorimetry accurately measured intraoperative metabolic changes during aortic surgery. It detected immediate decreases in oxygen uptake (VO2) and carbon dioxide elimination (VCO2) during aortic cross-clamping and subsequent increases after declamping.
Area of Science:
- Anesthesiology and Critical Care Medicine
- Physiology
- Surgical Metabolism
Background:
- Indirect calorimetry is established for ICU patient metabolic monitoring.
- Anesthetics can influence whole-body metabolism.
- Aortic cross-clamping significantly alters circulation and limb oxygen supply.
Purpose of the Study:
- To assess the feasibility of intraoperative indirect calorimetry during routine anesthesia.
- To determine if metabolic changes during surgery can be detected immediately.
- To evaluate the impact of abdominal aortic cross-clamping on oxygen uptake (VO2) and carbon dioxide elimination (VCO2).
Main Methods:
- Eleven patients undergoing aortic bifurcation reconstruction were studied.
- Total intravenous anesthesia (TIVA) with fentanyl and midazolam was administered.
- VO2 and VCO2 were continuously measured using a Deltatrac indirect calorimeter.
Main Results:
- Aortic cross-clamping significantly decreased VO2 (to 90%) and VCO2 (to 75% of baseline).
- Post-declamping, VO2 increased (110%), while VCO2 rose less (90%).
- The respiratory quotient decreased from 0.95 to 0.73 during surgery.
Conclusions:
- Indirect calorimetry is feasible for intraoperative metabolic monitoring during anesthesia.
- Aortic cross-clamping causes significant, detectable reductions in VO2 and VCO2.
- Metabolic recovery after declamping shows a greater increase in VO2 than VCO2, suggesting altered substrate utilization.