[Anesthesiologic aspects of minimally invasive surgery]

Minimal invasive, or more specifically laparoscopic surgery is now the standard procedure in an increasing number of surgical specialties. Inflating the abdomen with CO2 for long periods confronts the anesthesiologist with a number of problems that influence the choice of anesthetic and the monitoring deemed necessary. The increased intraabdominal pressure (IAP) and for some operations the extreme Trendelenburg position can disturb alveolar ventilation and compromise oxygenation. Pulse oximetry is therefore required to recognize and counteract these effects. The insufflated CO2 is absorbed into the blood to an unpredictable extent, and must be eliminated via the lungs by increasing the minute ventilation. Only capnometry or serial blood gas analyses can provide the information needed to correctly adjust the respiration. The endocrine stress reactions to laparoscopic surgery do not appear to be less pronounced than after conventional operations; only the interleukin-6 response to laparoscopic cholecystectomy is reduced compared to the subcostal incision. But minimal invasive surgery offers an advantage at least for cholecystectomy in that there is less impairment of postoperative respiratory function. General anesthesia will be the method of choice for laparoscopic surgery in all but a few procedures in which regional anesthesia is an acceptable alternative. Balanced anesthesia or total intravenous anesthesia is to be preferred, and the drugs employed should have rapid elimination kinetics with a short recovery time, since wound closure time is drastically reduced. Inhalational anesthesia alone may inhibit hypoxic pulmonary vasoconstriction thereby unduly increasing oxygen desaturation. The necessary degree of muscle relaxation still remains to be defined.