LAPAROSCOPIC INSUFFLATION OF THE ABDOMEN REDUCES PORTAL VENOUS FLOW

Background: The adverse effects of sustained elevated intraperitoneal pressure (IPP) on cardiovascular, pulmonary and renal systems have bee n well documented by several reported experimental and clinical studie s. Alteration in the splanchnic circulation has also been reported in animal experiments, but details of the exact hemodynamic changes in th e flow to solid intraabdominal organs brought on by a raised intraperi toneal pressure in the human are not available. The aim of the present study was to estimate effect of increased IPP on the portal venous fl ow, using duplex Doppler ultrasonography in patients undergoing laparo scopic cholecystectomy. Methods: The studies were performed using the SSD 2000 Multiview Ultrasound Scanner and the UST 5536 7.0-MHz laparos copic transducer probe. Details of the measurements were standardized in according to preset protocol. Statistical evaluation of the data wa s conducted by the two-way analysis of variance (ANOVA).Results: The f low measurement data have demonstrated a significant (p < 0.001) decre ase in the portal flow with increase in the intraperitoneal pressure. The mean portal flow fell from 990 +/- 100 ml/min to 568 +/- 81 ml/min (-37%) at an IPP of 7.0 mmHg and to 440 +/- 56 mmHg (-53%) when the I PP reached 14 mmHg. Conclusions: The increased intraperitoneal pressur e necessary to perform laparoscopic operations reduces substantially t he portal venous flow, The extent of the volume flow reduction is rela ted to the level of intraperitoneal pressure. This reduction of flow m ay depress the hepatic reticular endothelial function (possibly enhanc ing tumor cell spread). In contrast, the reduced portal flow may enhan ce cryoablative effect during laparoscopic cryosurgery for metastatic liver disease by diminishing the heat sink effect. These findings sugg est the need for a selective policy, low pressure or gas-less techniqu es to positive-pressure interventions, during laparoscopic surgery in accordance with the disease and the therapeutic intent.