Are there changes in leg vascular resistance during laparoscopic cholecystectomy with CO2 pneumoperitoneum?
BACKGROUND
The prompt haemodynamic response to carbon dioxide insufflation during laparoscopic cholecystectomy suggests involvement of the sympathetic system. The aim of the present study was to examine if a change in vascular resistance in leg skeletal muscle could be an important mechanism behind the increased afterload. Furthermore, the arterio-venous differences of the catecholamines were measured in the leg before and during insufflation of carbon dioxide into the peritoneal cavity.


METHODS
Ten patients (ASA I) scheduled for laparoscopic cholecystectomy were included. After induction of anaesthesia, catheters were introduced percutaneously into the radial artery, the femoral vein and the cubital vein for pressure monitoring and blood sampling. The arterial blood flow in the legs was measured by mercury-in-Silastic strain gauge venous occlusion plethysmography. Vascular resistance in the right leg (LVR) was calculated from the formula: (MAP-FVP)/calf blood flow. Measurements were made before and 5 min after insufflation of pneumoperitoneum.


RESULTS
Induction of pneumoperitoneum increased the heart rate (P < 0.05) and also increased mean arterial pressure and femoral vein pressure as well as the calculated leg vascular resistance (P < 0.01). Calf blood flow did not change significantly in either leg. Both arterial and venous noradrenaline concentrations were higher after insufflation (P < 0.01).


CONCLUSIONS
In patients without heart or lung disease, pneumoperitoneum at an intra-abdominal pressure level of 11-13 mmHg increased the peripheral vascular resistance in the leg while the arterial blood flow in the leg was unaffected. Catecholamine levels increased, but were still low. Therefore, we suggest that the increase in peripheral vascular resistance is caused by increased myogenic activity in the resistance vessels secondary to increased arterial and transmural pressure rather than by increased neurogenic sympathetic activity.
Andersson
L E
LE
Department of Anaesthesiology and Intensive Care, Karolinska University Hospital, S-141 86 Huddinge, Sweden. lena.e.andersson@karolinska.se
Jogestrand
T
T
Thörne
A
A
Sollevi
A
A
Odeberg-Wernerman
S
S
D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000008:administration & dosage*; D002395:Catecholamines / Q000097:blood; D017081:Cholecystectomy, Laparoscopic / Q000379:methods*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D018482:Muscle, Skeletal / Q000098:blood supply; D009638:Norepinephrine / Q000097:blood; D011028:Pneumoperitoneum, Artificial / Q000379:methods*; D012039:Regional Blood Flow / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology*
D002395:Catecholamines; D002245:Carbon Dioxide; D009638:Norepinephrine