Use of near-infrared spectroscopy to monitor regional cerebral oxygen saturation during infrarenal aortic crossclamping in piglets.
OBJECTIVE
The hemodynamic changes induced by infrarenal aortic crossclamping have been well documented, but the effects of such crossclamping on cerebral perfusion are unknown. To investigate these effects, we used near-infrared spectroscopy (NIRS) to monitor regional cerebral oxygen saturation (rSO2) during infrarenal aortic crossclamping in a piglet model.


METHODS
The study involved 19 piglets, each weighing 7.8 +/- 1 kg. The NIRS sensor was placed on each animal's forehead. General anesthesia was induced, and the infrarenal abdominal aorta was mobilized through a laparotomy. After heparin (1 mg/kg) was administered, crossclamps were applied proximally and distally. A 2 mm segment was resected from the proximal aortic stump, and an aorto-aortic anastomosis was performed.


RESULTS
Crossclamping lasted for 30.6 +/- 6.7 min. Between the time of baseline measurement and clamp application, the rSO2 did not decrease significantly (65.4%+/- 8.9% vs. 62.4%+/- 7.8%). However, significant decreases in the rSO2 occurred between baseline measurement and clamp removal (65.4%+/- 8.9% vs. 55.7%+/- 8.9%; P<0.01), between baseline measurement and the end of surgery (65.4%+/- 8.9% vs. 57.7%+/- 7.5%; P<0.01), and between clamp application and removal (62.4%+/- 7.8% vs. 55.7%+/- 8.9%; P<0.01). At these same intervals, no intergroup differences occurred in the temperature, heart rate, or mean arterial pressure.


CONCLUSIONS
Infrarenal aortic crossclamping significantly decreases the rSO2. NIRS, which has the advantages of being non-invasive and continuous, may be useful for monitoring this variable intraoperatively.
Undar
Akif
A
Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, TX 77030, USA. aundar@bcm.tmc.edu
LeMaire
Scott A
SA
Schmittling
Zachary C
ZC
Coselli
Joseph S
JS
Köksoy
Cüneyt
C
Deady
Blake A
BA
Fraser
Charles D
CD
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001011:Aorta / Q000601:surgery*; D001921:Brain / Q000378:metabolism*; D003250:Constriction; D016343:Monitoring, Intraoperative; D010100:Oxygen / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D013552:Swine; D014656:Vascular Surgical Procedures
D010100:Oxygen