Study of venous blood flow changes during laparoscopic surgery using a thermodilution technique

Background: Many modalities exist to analyse those factors that contribute to venous stasis and deep venous thrombosis (DVT) during laparoscopic surge ry. To the authors' knowledge intraoperative measurement of femoral venous blood flow has nor yet been performed nor has the influence of sequential c ompression devices been assessed using this parameter. Methods: The themodilution technique similar to that employed in cardiac ou tput measurement was used to determine changes in blood flow in the right f emoral vein during laparoscopic cholecystectomy. Deep venous thrombosis pro phylaxis involved perioperative use of sequential compression devices and s ubcutaneous heparin 5000 U. Results: Pneumoperitoneum and the Trendelenburg position reduced femoral ve nous return in four of the six patients studied, bur sequential compression devices failed to return blood flow to baseline in a predictable fashion. Conclusions: Although the measurement of blood flow using thermodilution is regarded as a reliable technique, during general anaesthesia the results m ay be susceptible to haemodynamic variations related to the anaesthetic age nts as well as to the laparoscopic procedure. In addition sequential compre ssion devices (when used alone) may not provide adequate prophylaxis agains t DVT because they do not predictably increase femoral blood flow.