HEMODYNAMIC-EFFECTS OF PROLONGED ABDOMINAL INSUFFLATION FOR LAPAROSCOPIC PROCEDURES

Abdominal insufflation for laparoscopic procedures leads to numerous h emodynamic effects. We focused on blood flow distribution and arterial and venous pressure changes during CO2 insufflation at an intra-abdom inal pressure of 12 mm Hg. Three segments of the vascular system were investigated (intrathoracic, cranial extrathoracic, caudal extrathorac ic) in supine animals at insufflation, during a 90-minute period of pn eumoperitoneum, and at desufflation. Except for instrumentation of the animals, no further surgery was performed. At insufflation (+5 minute s), cardiac output increased from 2.7 +/- 0.5 to 3.3 +/- 1.1 L/min whi le heart rate decreased from 138 +/- 26 to 128 +/- 17 beats per minute . Increases in jugular venous (from 6 +/- 1 to 11 +/- 4 mm Hg) and atr ial (right, from 7 +/- 1 to 12 +/- 3; left, from 12 +/- 4 to 17 +/- 5 mm Hg) pressures occurred uniformly during inspiration. The great vari ance in atrial pressures during ventilation was not associated with ch anges in stroke volume, as the effective transmural filling pressures remained nearly constant. The increase in femoral venous pressure occu rring during both inspiration and expiration (from 10 +/- 2 to 18 +/- 4 mm Hg) exceeded the increase in right atrial and jugular venous pres sures during inspiration. Parallel increases were noted in arterial pr essures (carotid, from 119 +/- 15 to 129 +/- 9; femoral, from 122 +/- 16 to 133 +/- 10 mm Hg), left ventricular pressure (from 133 +/- 17 to 143 +/- 10 mm Hg), and carotid and femoral flow (carotid, from 174 +/ - 71 to 195 +/- 70; femoral, from 66 +/- 25 to 73 +/- 40 (NS) mL/min). During pneumoperitoneum, arterial pressures, and flows, dLVP/dt, and tension time index decreased continuously below baseline while venous and atrial pressures were maintained. Heart rate increased at pneumope ritoneum. At desufflation, atrial and venous pressures decreased as th ey were directly related to mechanical strain, whereas the blood flows increased again. Abdominal insufflation was associated with increased cardiac output, cardiac contractility, and arterial pressures, at lea st initially. Although caudal venous resistance increased, blood flow distribution was not affected.