Respiratory compliance during laparoscopic hiatal and inguinal hernia repair

Side stream spirometry with dynamic compliance displayed as pressure-volume loops, has enabled early detection of CO2 pneumothorax during pneumoperitoneum. We compared dynamic compliance profiles of two laparoscopic procedures with different patient positions.

In 26 patients, scheduled either for laparoscopic fundoplication in a head-up tilt or inguinal herniorrhaphy in a head-down tilt, dynamic compliance was measured with continuous spirometry from anaesthesia induction until skin closure. Control pressure-volume loops were saved in the horizontal position before surgery and compared with succeeding loops in the head-up/head-down tilt before pneumoperitoneum, during pneumoperitoneum in the horizontal and the tilt position, after evacuation of pneumoperitoneum in the tilt and finally in the horizontal position.

Pneumoperitoneum reduced compliance in both groups by 35% (P < 0.01). Head-down tilt decreased compliance by 12% before and during pneumoperitoneum (P < 0.01). Head-up tilt increased compliance by 4% before pneumoperitoneum (P < 0.05), but during pneumoperitoneum it had no effect. After evacuation of pneumoperitoneum compliance returned immediately to control in head-up tilt, but remained reduced in head-down tilt and was not at control after adopting horizontal position (P < 0.05). Difference between the groups was significant (P < 0.01) in the head-up/head-down tilt before, during and immediately after pneumoperitoneum.

Both pneumoperitoneum and head-up and head-down positions had characteristic effects on dynamic compliance. Simultaneous display of sequential pressure-volume loops enabled immediate detection of changes in respiratory mechanics.