[Laparoscopic cholecystectomy--effect of position changes and CO2 pneumoperitoneum on hemodynamic, respiratory and...

The effect of laparoscopic cholecystectomy on cardiopulmonary and endocrinological parameters results from various factors such as increased intraabdominal pressure (IAP), CO2, and the positioning. However, positioning has not yet been regarded. Reliable examination of the individual influencing factors requires standardized anesthesiological procedure and constant IAP. Presently, the effect of positioning is observed separately from those effects caused by the pneumoperitoneum with CO2 (PP) under standardized conditions.

40 patients with no history of cardiopulmonary disease were analyzed. Preoperative medication, induction and management of general anesthesia, positioning of the patient and IAP (12 mmHg) were standardized. Hemodynamic, respiratory and endocrinological parameters were determined with the patient in a supine position and in the position typical for the procedure (15 degrees head-down and 10 degrees slant to the left), each with and without PP. Heart rate (ECG), endexpiratory pCO2 (peECO2), invasive blood pressure (radial art.), central venous pressure, partial arterial O2 saturation (psaO2), and ventilation pressures (peak, plateau) were monitored throughout anesthesia. The parameters pH, pCO2, BE, HCO3-, COHb, vasopressin, lactate, and ammonia were analysed in arterial and venous blood samples at predetermined set points: base line, 10 min after CO2 insufflation, 10 min after desufflation, and 1 h after extubation (cf. table 1). Statistical analysis was performed using the Wilcoxon-test with p < or = 0.05 considered statistically significant.

Insufflation of CO2 lead to a 12% increase of heart rate in supine position and to even 18% in the position required for surgery. Same significant changes were observed for arterial blood pressure (21 or respectively 28%). Central venous pressure increased by more than 200% after CO2 insufflation. Endexpiratory pCO2 increased by 2.4 mmHg after CO2 insufflation in the supine position and by 5 mmHg in the surgical position. Ventilation pressures increased significantly by 16%. Analysis of the effect of PP on blood gases showed that pH decreased from 7.47 to 7.43, and arterial pCO2 increased by 5.1 mmHg to 38.7 mmHg and increased further after desufflation to values of up to 43.9 mmHg. Arterial pO2 decreased steadily (18% after insufflation). Vasopressin plasma levels increased exponentially from 3.03 to maximal values of 104.45 pg/ml. Ammonia and lactate showed the expected, nearly identical course. Lactate increased within the clinically and methodically irrelevative range, from 1.12 to 1.159 mmol/l. Ammonia decreased by 29%.

The observed changes, i.e. heart rate, central venous pressure, and arterial blood pressure are caused and altered by CO2 insufflation and the various positioning of patients. The increased vasopressin concentration more than likely contributes to these changes. The query whether the position of the patient also causes a change in respiratory parameters and blood gas analysis cannot be differentiated except for the end-tidal pCO2. Inspite of the observed changes no cardiopulmonary complications occurred in this patient group. Therefore, it seems possible to omit invasive monitoring in cardiopulmonary healthy patients. In patients with concomitant history of cardiopulmonary disease, however, deteriorations due to laparoscopy should be thoroughly taken into consideration and studied further.