Central nervous system metabolic and physiologic effects of laparoscopy

We set out to determine whether the increases in intracranial pressure (ICP ) associated with CO2 insufflation had any metabolic effect on the central nervous system in a head injury when compared with gasless laparoscopy (GL) . To test this hypothesis, we looked at both the ICF and jugular bulb venou s saturation (JVS), with and without a coexisting cerebral mass lesion. Twe nty-five kilogram male pigs had tracheostomy, epidural balloon, pulmonary a rterial catheter, arterial line, and jugular bulb catheter placed. Intraven ous Pentobarbital was used for anesthesia. Either CO2 laparoscopy (CL; n = 7) or GL (n = 7) were performed both with and without an epidural balloon i nflated to a baseline ICP of 25. Data were analyzed using the Student's t t est with a P value <0.05 being significant. Cerebral perfusion pressure and most hemodynamic values did not differ. Both central venous pressure and p eak inspiratory pressure were significantly elevated whenever CO2 insufflat ion took place, reflecting an increased intrathoracic pressure. When compar ing both study groups, the partial pressure of CO2 did not differ. CL incre ases ICP significantly above the gasless group in pur head injury model. Th is is most likely secondary to increased intrathoracic pressure. The questi on still remains whether these changes are clinically significant. We could not demonstrate significant metabolic effects secondary to laparoscopy. In patients suffering head injury, GL rather than CL might be safer to avoid ICF elevation. Additional studies looking at central nervous system metabol ic and objective histopathologic effects should be undertaken with larger n umbers of study animals.