Kidney safety during surgical pneumoperitoneum: an experimental study in rats Roge ´rio Fortunato de Barros • Ma ´rcio Lopes Miranda • Amilcar Castro de Mattos • Jose ´ Antonio Rocha Gontijo • Vinicius Rodrigues Silva • Brayner Iorio • Joaquim M. Bustorff-Silva Received: 25 January 2012 / Accepted: 24 April 2012 Ó Springer Science+Business Media, LLC 2012 Abstract 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 sec- ondary 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 pneumoperi- toneum), group 3 (2-h control), group 4 (2-h pneumoperi- toneum), 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 eval- uation 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. Keywords N-GAL  Rats  Renal injury  Surgical pneumoperitoneum Laparoscopy currently is a recognized surgical approach that has greatly benefited patients, significantly reducing operative time and morbidity and resulting in a better postoperative recovery. However, a few physiologic complications are closely asso- ciated with gas insufflation under pressure in the abdominal cavity of mammals [1–8]. Sudden and erratic elevations of intraabdominal pressure (IAP) can lead to a variety of adverse events during laparoscopic abdominal surgical procedures such as decreased venous return, subcutaneous emphysema, impaired ventilation, risk of gas embolism, and even abdominal com- partment syndrome [ 9], especially in small mammals [7, 8]. Oliguria during pneumoperitoneum has been observed in numerous experimental studies, demonstrating a signif- icant and reversible decrease in renal blood flow, urinary output, and glomerular filtration rate during the insuffla- tions [1–8]. Findings have shown these effects to be pres- sure dependent. In the literature, decreased renal blood flow from vascular compression, ureteral obstruction, and systemic hormonal effects or direct renal compression are hypothesized to be possible causes of oliguria [10]. R. F. de Barros  M. L. Miranda  B. Iorio  J. M. Bustorff-Silva (&) Division of Pediatric Surgery, University of Campinas, Campinas, SP, Brazil e-mail: bustorff@hc.unicamp.br A. C. de Mattos Department of Pathology, University of Campinas, Campinas, SP, Brazil J. A. R. Gontijo  V. R. Silva Laborato ´rio de Metabolismo Hidro-Salino, Nu ´cleo de Medicina e Cirurgia Experimental, University of Campinas, Campinas, SP, Brazil 123 Surg Endosc DOI 10.1007/s00464-012-2322-4 and Other Interventional Techniques