Complications des postures en anesthésie

Hemodynamic disturbances induced by postural changes are related to blood sequestration in the capacitive venous system depending on gravity and worsened by baroreflex depression due to anesthetic agents. Hydrostatic pressure may make different the values of arterial pressure measured at the level of the operating table, and at a higher or lower level. Gravity and decreased muscle tone result in decreasing FRC. Pulmonary inflation maneuvers prevent the development of atelectasia and the consecutive shunting. Most of postural complications are favored by unpredictable individual parameters and by maintenance of unusual positioning thanks to anesthesia. The common mechanism is the occurrence of tissue ischemia due to compression or stretching. Ulnar nerve and plexus brachial trauma are the most common peripheral nerve damages under anesthesia. Ulnar nerve lesions are likely due to anatomical specificity. Every peripheral nerve lesion requires a complete electrophysiological investigation combined with motor and sensitive testing that will possibly diagnose a preexisting neuropathy. Corneal abrasion, prevented by lid occlusion, is the most common ocular lesion that may lead to definitive sequelae. Central retina artery (unilateral) occlusion may result from ocular compression and ischemic optic (bilateral) neuropathy may lead to severe vision disturbance. The responsibility of patient positioning is shared in between anesthetist and surgeon.