Proximal subcutaneous interstitial fluid pressure during cross-clamping of the descending thoracic aorta: A study of patients operated on for thoracic- or thoracoabdominal aortic aneurysms

Abstract

Seven patients were operated on for thoracic (n = 2) or thoracoabdominal (n = 5) aortic aneurysms during cross-clamping of the aorta. Interstitial tissue fluid pressure was measured at the neck during cross-clamping of the descending thoracic aorta by the wick-in-needle technique, whereas control measurements were obtained prior to cross-clamping. The subcutaneous interstitial fluid pressure was significantly higher on the neck during cross-clamping of the thoracic aorta compared with control measurements (median 3.7 mmHg vs −0.6 mmHg, p < 0.05). Increased subcutaneous interstitial tissue pressure of the upper part of the body is probably caused by increased capillary filtration rate induced by inhibited autoregulatory functions during aortic cross-clamping. The pressure measurements objectively confirm the problem of edema formation of the head and neck during these operations. The edema may occasionally affect the upper airways and represent a problem for intubation of the patient in the postoperative phase.