Hemodynamic and hormonal changes during pneumoperitoneum and trendelenburg positioning for operative gynecologic laparoscopy surgery

CARDIOVASCULAR, HEMATOLOGIC, AND PULMONARY sured in the dominant index finger while breathing room air with a Nelcor N-200 pulse oximeter and DS-100A sensor (Nellcor Puritan Bennett, Pleasanton, CA) at set antepartum (AP) and postpartum (PP) intervals. Oxygen saturation was measured in the following positions: sitting, lying on the left then right side, knee-chest, and supine. Five minutes were allowed between measurements. Measurements were taken at 12, 24, and 36 weeks of gestation and then at 12 weeks postpartum for each patient. Results: Thirty-six patients were initially enrolled. Three were excluded from this study, secondary to loss of follow-up (1), preterm delivery at 35 weeks (1), and complicated placenta previa (1). Of the 33 patients who remained in the study 5 have delivered and undergone postpartum evaluation. SpO2 values (%) are summarized as mean 6 2 SD in the Table. Maternal Position

12 wk AP 24 wk AP 36 wk AP 12 wk PP (n 5 33) (n 5 33) (n 5 16) (n 5 5)

Standing Sitting Knee chest Left lateral Right lateral Supine

99.7 6 0.6 99.7 6 0.4 99.6 6 0.7 99.6 6 0.6 99.7 6 0.1 99.7 6 0.6

99.4 6 1.0 99.5 6 0.8 99.4 6 0.7 99.0 6 1.4 99.3 6 0.9 99.2 6 0.3

98.1 6 1.1 99.1 6 0.9 98.8 6 1.4 99.0 6 1.1 98.7 6 1.1 98.9 6 1.1

98.6 6 0.6 99.6 6 0.6 99.2 6 0.5 99.2 6 0.8 98.9 6 0.9 99.4 6 0.6

Conclusion: Preliminary data in this ongoing descriptive longitudinal study suggest that maternal SpO2 is at least 97% throughout pregnancy for healthy, non-smoking women residing at sea level. These normative data may be useful in managing pregnant women at risk for hypoxia.

Hemodynamic and hormonal changes during pneumoperitoneum and Trendelenburg positioning for operative gynecologic laparoscopy surgery Jennifer Stone, CRNA, MS, LuAnn Dyke, CRNA, MS, Patricia Fritz, CRNA, MS, Martie Reigle, CRNA, MS, Harland Verrill, PhD, Kumbla Bhakta, MD, Guy Boike, MD, James Graham, MD, Francis Gerbasi, CRNA, PhD University of Michigan-Flint/Hurley Medical Center Objective: The number and types of surgical procedures being preformed using laparoscopic technique is increasing due to technological advances. Recent studies suggest the carbon dioxide pneumoperitoneum and patient positioning causes hemodynamic alterations, respiratory acidosis, and a release of stress hormones. However, to date, no studies have investigated the physiological effect of laparoscopic procedures lasting more than 60 minutes on the stress response and the effect of Trendelenburg positioning. The purpose of this study was to identify the physiological effect of pneumoperitoneum and positioning during prolonged laparoscopy on hemodynamic (cardiac index, mean arterial pressure, heart rate, systemic vascular resistance, and stroke volume), metabolic Volume 5, Number 4, 1998

(arterial blood gases), and hormone (arginine vasopressin, aldosterone, and plasma renin activity) parameters. We hypothesized that pneumoperitoneum and patient positioning will alter the hemodynamic, hormone, and metabolic parameters. Methods: The study was longitudinal in design and sampled a total of 31 healthy subjects having a gynecologic oncologic laparoscopic procedure at Hurley Medical Center, Flint, Michigan. The subjects were randomly assigned one of three groups receiving an initial insufflation pressure of either 10, 15, or 18 mmHg. After obtaining informed consent hemodynamic, metabolic, and hormone measurements were obtained at the following times: 1) pre-induction, 2) post-induction, 3) post-insufflation, 4) post-Trendelenburg 5 minutes and at 30, 60, 90, and 120 minutes post-insufflation. The results were analyzed using multivariate analysis of variance for repeated measures with a P , .05. A power of 0.9 was obtained to identify changes over time. Results: During the time course of the study the hemodynamic, metabolic, and hormonal parameters showed significant alterations. The most dramatic hemodynamic changes occurred post-insufflation characterized by a decrease in cardiac index and stroke volume with a concurrent increase in systemic vascular resistance. The metabolic parameters showed a significant decrease in pH and corresponding increase in PaCO2. However, the pH and PaCO2 remained within normal limits through the study. As part of the study’s protocol the investigators increased minute volume to control for a rise in PaCO2 during the procedure. A significant increase was noted in aldosterone and arginine vasopressin at postinsufflation and Trendelenburg positioning. Plasma renin activity showed a dramatic increase following post-insufflation. None of the subjects developed any post anesthetic complications. Conclusion: Our study demonstrated that pneumoperitoneum and Trendelenburg positioning cause statistically significant elevations in the stress hormones and concurrently cause a decrease in hemodynamic parameters. A healthy patient may tolerate these changes but a patient with cardiovascular disease or pulmonary problems may not be able to compensate as efficiently.

Incidence, clinical characteristics, and timing of objectively diagnosed venous thromboembolism during pregnancy Robert B. Gherman, MD, T. Murphy Goodwin, MD, Belinda Leung, MD, James D. Byrne, MD, Martin Montoro, MD Dept. OB/GYN, Division of Maternal-Fetal Medicine, University of Southern California School of Medicine, Los Angeles, California Objective: To determine the incidence, timing, and associated clinical characteristics of objectively diagnosed pregnancyassociated venous thromboembolism (VTE). 155