Kidney safety during surgical pneumoperitoneum: an experimental study in rats.

BACKGROUND: Elevations of intraabdominal pressure during laparoscopic procedures may lead to oliguria or anuria in mammals. Despite this, previous research has not been able to confirm an associated kidney injury. This study aimed to investigate the occurrence of an early kidney lesion secondary to surgical pneumoperitoneum in a rat model using the expression of neutrophil gelatinase-associated lipocalin (N-GAL) as a biomarker for early kidney injury. METHODS: In this study, 20 male Sprague-Dawley rats under general anesthesia and mechanically ventilated were allocated to one of five experimental time-dependent groups: group 1 (1-h control), group 2 (1-h pneumoperitoneum), group 3 (2-h control), group 4 (2-h pneumoperitoneum), and group 5 (positive kidney injury group induced by intravenous administration of cisplatin 7.5 mg/kg). To evaluate the renal expression of N-GAL 24 h after the procedure, all the rats underwent a 2-h urine output evaluation as well as laparotomy and bilateral nephrectomy performed sequentially to investigate the presence of renal injury using immunofluorescence qualification and western blotting. RESULTS: Urine output was reduced and N-GAL expression was increased in the animals from the cisplatin group. The animals undergoing 1- or 2-h pneumoperitoneum displayed urine output and N-GAL expression similar to that of the animals from the matching control groups. CONCLUSIONS: Under the experimental conditions of this study, the animals with normal preoperative renal function did not show any type of acute kidney injury associated with the presence of a stabilized surgical pneumoperitoneum.

Evaluation of a simple valve mechanism used to stabilize intraabdominal pressure during surgically induced pneumoperitoneum in small animals.

BACKGROUND: Preventing sudden changes in intraabdominal pressure (IAP) during surgical pneumoperitoneum may reduce adverse events. This study aimed to describe a valve system that stabilizes intraabdominal pressure, minimizing complications of erratic fluctuations in IAP. METHODS: Five male Sprague-Dowley rats were submitted to pneumoperitoneum, with the insufflator set sequentially at 5, 10, and 15 mmHg for each rat. Measures of IAP were taken initially without the valve and then using the same insufflator levels with the valve system regulated to three different pressures (5, 10, and 15 mmHg). The mean of the three highest registered pressures during a 15-min observation was used as the maximal pressure, and the mean of the three lowest registered pressures was used as the minimal pressure for each experimental setting. RESULTS: Without the valve system, the pressure level set by the insufflator correlated poorly with the actual IAP. When the valve system was used, the IAP pressure was limited by the valve settings regardless of the insufflator settings. Also, the variability of IAP was significantly higher when no valve was used than in all situations that had implementation of the system. CONCLUSIONS: The valve system was very effective in stabilizing IAP, allowing a reproducible and reliable estimate of IAP and greatly reducing the variability resulting from the cycling mechanism of the insufflator. Due to the small dimensions of intracorporeal cavities in the newborn, this mechanism may help to improve safety when neonatal video-assisted surgery is performed.