[Respiratory and circulatory changes under high intra-abdominal pressure].

In order to determine the safety limit of abdominal pressure, the influence of abdominal pressure on the respiratory and circulatory systems was examined by changing it from 0 to 50 mmHg in dogs with carbon dioxide insufflation. Total peripheral resistance increased slightly after pneumoperitoneum but increased rapidly when 30 mmHg was exceeded. Cardiac output tended to decrease with an abdominal pressure above 30 mmHg. Static compliance decreased in response to the abdominal pressure up to 20 mmHg but the decrease became rather gentle when 30 mmHg was exceeded. Peak inspiratory airway pressure increased in response to the increased abdominal pressure up to 30 mmHg followed by small fluctuations thereafter. These evidences indicate that an abdominal pressure below 15 mmHg is desirable for performing a peritoneoscopic operation safely because the biocompensatory system may be impaired when the pressure exceeds 30 mmHg.