Impedance cardiography: noninvasive assessment of hemodynamics and thoracic fluid content during bariatric surgery.

BACKGROUND

The effects of pneumoperitoneum (ppm) on hemodynamic parameters during bariatric surgery were investigated using the impedance cardiography monitor.

METHODS

11 patients with BMI 46.5+/-10 kg/m2 (range 38.9-60.8 kg/m2) underwent laparoscopic adjustable gastric banding under general anesthesia. Besides routine monitoring, the impedance cardiography (ICG) monitor was used to monitor cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), and thoracic fluid content (TFC). Data were recorded at three stages: A) before ppm, B) during ppm, and C) after gas deflation. One-way analysis of variance (ANOVA) was used to analyze differences of the data before, during and after ppm, and post-hoc (Bonferoni test) for multiple comparisons of the data obtained. For all comparisons, P<0.05 was considered significant.

RESULTS

There were significant low mean values of heart rate (HR), CO and CI at stage B compared to stage A (P<0.05). The mean values of TFC at stages A, B, and C were 30.48 +/- 4.69, 29.74 +/- 2.86 and 31.72 +/- 4.93 k/Ohm respectively, with a non-significant relationship (P>0.05). The mean values of SVR during the same stages A, B and C were 1299.18 +/- 374.40, 1873.64 +/- 276.26 and 1669.36 +/- 537.92 dynes sec cm(-5) respectively, with significant high mean values at stages B and C compared to mean value at stage A (P<0.05).

CONCLUSIONS

Morbid obesity and pneumoperitoneum have significant effects on hemodynamics. However, it appears that these changes were of marginal clinical significance.