Effect of pneumoperitoneum on renal tissue oxygenation and blood flow in a rat model

OBJECTIVES

To determine the correlation between the renal blood flow (RBF) and tissue oxygenation (PO(2)) at varying intra-abdominal pressures (IAPs) and to compare the effects on renal blood flow from carbon dioxide-induced pneumoperitoneum.

METHODS

Carbon dioxide pneumoperitoneum was established in Sprague-Dawley rats (n = 6). Licox oxygen/temperature tissue probes were laparoscopically inserted into the renal parenchyma, with the renal PO(2) and RBF recorded every 30 seconds while the IAP was gradually increased. Microprobes measuring the RBF, mean arterial pressures and serum pH were placed into the parenchyma to compare the effects of carbon dioxide pneumoperitoneum (n = 7) with that of open surgery (n = 6) and medical air pneumoperitoneum (n = 6).

RESULTS

Renal PO(2) was inversely related to the IAP (P < .001). Despite the reduction in IAP, the renal PO(2) in the recovery phase was lower than at baseline (P = .045). The renal PO(2) and RBF changed in a virtually identical pattern at varying levels of IAP (P > .05). The RBF significantly declined with a pneumoperitoneal pressure of 15 and 20 mm Hg (P = .022), regardless of the gas used to create the pneumoperitoneum. A partial reversal of the RBF occurred with a decrease of the IAP. The RBF in the open surgical arm remained unchanged. Although both the serum pH and the mean arterial pressure were inversely proportional to the IAP (P < .001), the mean arterial pressure was depressed to the greatest extent in the medical air group (P = .02).

CONCLUSIONS

These results have demonstrated that elevated IAP secondary to pneumoperitoneum causes significant renal hypoxia and decreased RBF. Additionally, this experiment has demonstrated the use of the Licox probes in monitoring the renal PO(2) and established a novel method for evaluating the effects of IAP on the kidney.

Autologous pericardial patch without infarctectomy for the treatment of acute cardiac rupture

Acute cardiac rupture is a complication of acute myocardial infarction and is often a lethal condition. The successful management of a case of left ventricular rupture by patch repair with concomitant myocardial revascularization is reported. Pre- and postoperative hemodynamic stabilization was achieved with the aid of intra-aortic balloon pump counterpulsation.

Inter- and intraobserver reliability of walking-track analysis used to assess sciatic nerve function in rats

The inter- and intraobserver reliability of the walking-track analysis of sciatic nerve function in the rat was assessed. Twenty-five walking tracks were assessed on three different occasions by four observers. Whereas the interobserver reliability was found to be excellent (r = 0.92), the intraobserver reliability was only satisfactory (r = 0.53 to r = 0.76). Walking-track analysis provides a noninvasive technique to assess function recovery in the rat, with excellent intraobserver reliability demonstrated. The lower intraobserver reliability suggests limitations to this new measurement technique.