Influence of pneumoperitoneum and patient positioning on preload and splanchnic blood volume in laparoscopic surgery of the lower abdomen

Study Objective: To determine the hemodynamic effects of pneumoperitoneum a nd patient positioning during laparoscopic surgery of the lower abdomen. Design: Prospective study. Setting: University-affiliated medical center. Patients: 10 ASA physical I and physical II female patients scheduled for a laparoscopic surgery of the lower abdomen. Interventions: patients were anaesthetized with propofol and an alfentanil infusion, then intubated and normoventialted. Measurements: After intubation, a transeophageal multiplane probe for measu rements of right (RVESA) and left (LVESA) ventricular end-systolic and end- diastolic areas (RVEDA and LVEDA) and ejection fraction area (RVEFa, LVEFa) was introduced; heart rate (HR) and noninvasive blood pressure (BP) were r ecorded every minute. Ventilation was not changed during the measurements. A transvaginal ultrasound probe was inserted to measure the the diameter of the common iliac vein. Measurements were performed 15 minutes after induct ion of anesthesia and white patients were in the supine position (P 0), 10 minutes after CO2 insufflation to 10 mmHg IA pressure (P 10), 10 minutes af ter a further increase to 15 mmHg (P 15), 10 minutes after 20 degrees Trend elenburg (P 15 T), and 20 degrees reverse Trendelenburg positions (P 15 RT) . Data are shown as medians, 25th to 75th percentiles, and comparisons betw een P 0, P10, P15 and P15 T were made with the Friedman test, followed by W ilcoxon test, when significant. Data at P 15 T, P 15 RT,and P 15 were comap red using the Wilcoxon test, with a p-value < 0.05 regarded as significant. Main Results: Pneumoperitoneum at 10 mmHg abdominal pressure caused signifi cant increase of LVESA by 78% (RVESA: 61%) and LVEDA by 48.5% (RVEDA: 45%). The diameter of the common iliac vein was decreased by 6%. A further incre ase of abdominal pressure to 15 mmHg led to an additional increase of 20% ( LVESA) and I7% (LVEDA). Mean arterial pressure increased by a significant 7 % at P 10, decreasing subsequently by 5% at P 15. The Trendelenburg positio n did not alter any hemodynamic findings. Reverse Trendelenburg position, h owever, caused a significant LVEDA - and RVEDA - decrease by 18% and 27%, r espectively and an increase in the diameter of the common iliac vein by 22% . The LVEFa and RVEFa decreased significantly after abdominal CO2 insufflat ion by 18% each (P 10) without further change. Conclusions: The lithotomy position and subsequent pneumoperitoneum increas ed preload, probably as a result of blood shifting from the abdomen to the thorax by compression of splanchnic vessels caused by the pneumoperitoneum. Careful fluid management, maintaining low abdominal pressure, and use of t he reverse Trendelenburg position are favored to prevent adverse hemodynami c effects in laparoscopic surgery. (C) 2001 by Elsevier Science Inc.