Pattern and causes of hemodynamic changes during hepatic resection]

The aim of this study was to determine the causes and pattern of hemodynamic changes during hepatic resection, performed without vascular exclusion technique, and to select the most appropriate methods for monitoring patient's condition during the surgery.This prospective study included 55 ASA class I-III patients who had undergone hepatic resection surgery at the Clinic of Surgery, Hospital of the Lithuanian University of Health Sciences (former Kaunas University of Medicine) in 2003-2008. Additional monitoring of central hemodynamic parameters, arterial blood pressure, central venous pressure, and pressure in the inferior vena cava using invasive methods was performed.During the surgery, hypotension episodes (n=186) occurred in 53 out of 55 patients with a mean of 3.4 (SD, 2.0) episodes per patient. Changes (n=262) in femoral vein pressure were observed in 54 out of the 55 patients with a mean of 4.8 (SD, 3.2) episodes per patient. During the hypotension episode, significant changes in the mean arterial blood pressure, femoral vein pressure, cardiac output, cardiac index, systemic vascular resistance index, and central venous pressure were documented. There was a significant positive correlation between blood loss and number of changes in femoral vein pressure (r=0.5; P<0.001). Blood loss of more than 450 mL was observed in 69.0% of patients with increasing and 38.2% of patients with decreasing central venous pressure (P<0.01). Less than half (41.6%) of patients in the group of negative change in femoral vein pressure and 88.0% in the group of positive change in femoral vein pressure lost more than 450 mL of blood (P<0.001).The most common hemodynamic changes during hepatic surgery include hypotension, decreased cardiac output and cardiac index, and elevated pressure in the inferior vena cava. More common cause of hypotension was clamping of the inferior vena cava, and less common was blood loss. Blood loss was related to the number of clamps of the inferior vena cava and increasing pressure in the superior vena cava. A cause of hypotension during hepatic resection may be determined by pressure monitoring in the superior and inferior vena cava.