Background: Positive pressure pneumoperitoneum (PP) may involve adverse pathophysiological changes, including increased intra-thoracic and ocular pressure, when combined with standard ventilation. High frequency jet ventilation (HFJV) was reported to reduce the adverse cardiovascular effects during laparoscopic cholecystectomy.

Aim: To study the effects of HFJV on intra-ocular pressure changes (reflecting intra-cranial pressure) during laparoscopic surgery under PP.

Patients and methods: The investigators studied 2 groups of patients electively scheduled for laparoscopic cholecystectomy. The study group included 10 patients that were ventilated by high frequency jet ventilation (HFJV). In the control group (16 patients) the investigators used the standard intermittent positive pressure ventilation (IPPV). Both groups were matched according to clinical and hemodynamic parameters. Intra-ocular pressure was measured by a senior ophthalmologist that was blinded to the ventilation technique. Laparoscopic surgery was done as usual, and the intra-peritoneal pressure was automatically set on 14 mmHg. Statistical significance was considered whenever P value was less than 0.05.

The investigators anticipate that the use of HFJV during laparoscopic operations under PP may prevent increased intra-ocular pressure that accompanies increased intra-abdominal pressure under conventional ventilation (IPPV).

Inclusion Criteria:

• Patients undergoing elective laparoscopic cholecystectomy

Exclusion Criteria:

• Ophthalmologic and severe Cardiopulmonary diseases