Effect of Special Intraoperative Conditions on the Respiratory Effects of Anesthesia

Some special intraoperative conditions (such as surgical position, massive blood loss, and surgical retraction on the lung), may cause impaired gas exchange. For example, some of the surgical positions (i.e., the lithotomy, jackknife, and kidney rest positions) and surgical exposure requirements may decrease QT, may cause hypoventilation in a spontaneously breathing patient, and may reduce FRC. The type and severity of preexisting respiratory dysfunction, as well as the number and severity of special intraoperative conditions that can embarrass respiratory function, will magnify the respiratory depressant effects of any anesthetic.