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Assessment of left ventricular performance during laparoscopy.

OBJECTIVES
Cardiovascular changes during laparoscopic surgery have been described in several studies. Pneumoperitoneum effects on cardiac performance instead have not been much investigated and are less known. The carbon dioxide insufflation necessary in order to perform laparoscopic procedures represents a higher force against which the myocardial fibers must shorten during ventricular contraction. Hypothesis of this study is that the intra-abdominal pressure at 12 mmHg could acutely affect the left ventricular wall stress and work. Aim of the study was to evaluate the impact of relationship pneumoperitoneum on the echocardiographic measures of left ventricular contractile function.


PATIENTS AND METHODS
We studied 20 healthy, ASA I women, undergoing laparoscopic hysterectomy. Transthoracic echocardiography was performed preoperatively, after induction of anaesthesia, 15' after pneumoperitoneum, 15' after Trendelenburg positioning and 15' after the end of surgery. Left ventricular end-systolic wall stress, stroke work, left ventricular ejection time and mean velocity of fiber shortening were registered.


RESULTS
Carbon dioxide insufflation caused a consistent increase in left ventricular end-systolic wall stress and left ventricular ejection time, while the mean velocity of fiber shortening decreased. The Trendelenburg position did not produce any other signficant effects. These changes were transient with a return to preinsufflation values at the last measurement. Pneumoperitoneum adversely affects left ventricular performance during laparoscopy, leading to an increase of left ventricular end-systolic wall stress and reducing the mean velocity of circumferential fiber shortening. These cardiac consequences appear to be reversible since all the echocardiographic parameters normalized at the end of surgery.


CONCLUSIONS
Our results suggest that there is an adaptation of the cardiac systolic contractile status to the pressure overload during laparoscopy.