Effects of pneumoperitoneum induced at various pressures on cardiorespiratory function and working space during laparoscopy in cats.
OBJECTIVE
To evaluate the effect of pneumoperitoneum on cardiorespiratory variables and working space during experimental induction of 3 intra-abdominal pressures (IAPs) in cats.


METHODS
6 healthy young adult neutered male domestic shorthair cats.


METHODS
All cats were anesthetized through use of a standardized protocol. A catheter was placed in the right femoral artery for blood pressure and blood gas monitoring. A thermodilution catheter was placed in the right jugular vein via fluoroscopic guidance. Cardiopulmonary variables were measured before (baseline) and 2 and 30 minutes after initiation of pneumoperitoneum at IAPs of 4, 8, and 15 mm Hg; these were created through the use of a mechanical insufflator. At each IAP, abdominal dimensions (height, width, and circumference) were measured at a standardized location.


RESULTS
At 4 mm Hg and 8 mm Hg IAP, no clinically important changes were identified in cardiorespiratory values. Heart rate, cardiac index, and stroke volume index remained unchanged throughout the study at all IAPs. Mean arterial blood pressure began to increase at 8 mm Hg and was significantly higher, compared with baseline, at both time points at 15 mm Hg. At 15 mm Hg, Paco2 was significantly higher and cats were more acidotic than at baseline. Working space was subjectively greater at 8 mm Hg than at 4 mm Hg IAP; however, at 15 mm Hg, no clinically important enlargement of the working space was identified, compared with at 8 mm Hg.


CONCLUSIONS
Values of cardiopulmonary variables were largely unchanged by induction of pneumoperitoneum in healthy cats up to an IAP of 8 mm Hg, and no clinically important increases in working space were evident at an IAP of 15 versus 8 mm Hg. These findings provide little justification for use of IAPs > 8 mm Hg in healthy cats undergoing laparoscopic procedures; however, whether the situation is similar in diseased or elderly cats remains to be determined.
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616.
Philipp D
PD
Mayhew
Peter J
PJ
Pascoe
Philip H
PH
Kass
Yael
Y
Shilo-Benjamini
D000818:Animals; D001784:Blood Gas Analysis / Q000662:veterinary; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D002302:Cardiac Output / Q000502:physiology; D002415:Cats / Q000601:surgery*; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D007530:Isoflurane / Q000378:metabolism; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D010092:Oximetry / Q000662:veterinary; D011028:Pneumoperitoneum, Artificial / Q000379:methods* / Q000662:veterinary*; D011312:Pressure; D056152:Respiratory Rate / Q000502:physiology; D013997:Time Factors
D002245:Carbon Dioxide; D007530:Isoflurane