TITLE: INFLUENCE OF DIFFERENT ANESTHETIC TECHNIQUES ON TISSUE OXYGEN TENSIONS UNDER INCREASED FiO₂

AUTHORS: Marc A. Burmeister, MD, Ernst P. Horn, MD, Frank Schroeder, MD, Thomas Standl, MD, Jochen Schulte am Esch, MD
AFFILIATION: University of Hamburg, Hamburg, Germany.

INTRODUCTION: Tissue oxygen tension (tpO₂) is a predictor of wound infection after surgery¹. Therefore, supplemental oxygen administration by increased FiO₂ may reduce the postoperative wound infection rate². The present study examines the effects of different anesthetic techniques on tpO₂ under increased FiO₂ in gynecological patients.
METHODS: After IRB approval and written informed consent general anesthesia was induced with fentanyl and propofol in 45 female patients. Anesthesia was randomly maintained with Isoflurane with N₂O (Iso+N), without N₂O (Iso-N) or with propofol (TIVA). At the end of surgery the FiO₂ was stepwise increased (0.4, 0.6, 0.8, 1.0). Arterial blood gases, intramuscular tpO₂ (Eppendorf needle probe), HR, MAP, tympanon temperature and Hb were measured. Unpaired, two-tailed t-test and the Mann-Whitney-U test were used for statistic analysis.
RESULTS: No differences were found with respect to demo- graphic data, temperature, hemodynamics and blood gases between groups at all measurepoints. The median tpO₂ increased linearly in all anesthetic groups with increased FiO₂ (Iso+N: 51, 71, 84, 97; Iso-N: 61, 71, 83, 94; TIVA: 60, 70, 87, 99 mmHg).
CONCLUSION: During general anesthesia with different anesthetic techniques (Isoflurane, N2O, TIVA) oxygen tension of peripheral tissue increases linearly to increased FiO₂ in all groups. Thus, the obtained tpO₂ enhancement during anesthesia may be benefitious to decrease the postoperative wound infection rate.
REFERENCES:

1. Arch Surg 1997;132:997-1005.

2. Arch Surg 1984;119:199-204.