BACKGROUND: To establish reliable evidence regarding the adequate positioning of the tip of a Veress needle in the interior of the peritoneal sac during the establishment of the pneumoperitoneum by the closed technique. METHODS: In 11 pigs, the needle was introduced in the peritoneal sac through the left hipocondrium. Tests of positioning of the tip of the instrument were carried out. Gas (CO2) was injected, and pressures, flows and volumes were registered periodically. The correct intraperitoneal position of the needle was confirmed and, subsequently, removed, being reintroduced in the right hipocondrium and placed under direct vision in the pre-peritoneal space. The same parameters were surveyed. RESULTS: The test of the draining was always positive in the peritoneum. Resistance to the infusion of serum in the peritoneal sac was not observed, but resistance was detected on 45.5% of cases in the pre-peritoneal space. Some serum was recouped in 63.5% of cases in the peritoneal sac and in 54.5% in the pre-peritoneal space. The dripping flowed freely in 66.6% of cases in the peritoneal sac and in 45.5% in the pre-peritoneal space. In the peritoneal sac, = 5mmHg initial pressure increased gradually during 120 seconds until reaching 15 mmHg. In the pre-peritoneal space, the initial pressure was of 15mmHg and oscillated between 12 and 15mmHg. The volume of gas injected was of 1500 ml in the peritoneal sac and of 100 ml in the pre-peritoneal space. CONCLUSION: Initial pressure of ±5mmHg is indicative of the tip of the needle being placed in the peritoneal sac, inside of which there should fit ten times more gas than in the pre-peritoneal space. When the tip of the Veress needle is placed in the interior of the peritoneal sac, the increase of intraperitoneal pressures and volumes can be predicted by statistics.
Laparoscopy; Laparoscopic, surgery; Surgery, operative; Pneumoperitoneum, artificial; Pneumoperitoneum; Needles; Punctures; Peritoneal cavity; Surgery, minimally invasive; Surgery, veterinary
