The massively bleeding patient.

The resuscitation of the massively bleeding patient may seem superficially to be successful once the patient's vital signs have stabilized. The restoration of stable vital signs, however, does not confirm two critical elements of a thorough physiologic resuscitation: that there is truly adequate delivery of oxygen to all tissue beds and that physiologic disturbances that may have occurred because of massive transfusion during the resuscitation process have resolved. With respect to the adequacy of oxygen delivery, the current clinical endpoints, including mixed venous oxygen saturation, cardiac output, and serum lactate, reflect global perfusion and not regional oxygenation. Of these global measures, serum lactate is currently the best indicator as to whether some circulatory beds remain inadequately perfused. Serum lactate should be followed, and, in the event that elevated levels persist, measures to augment oxygen delivery (e.g., increasing cardiac output, hemoglobin concentration, oxygen saturation) should be undertaken. Gastric tonometry provides a method for specific examination of the splanchnic circulation. The current measurement techniques, however, require steady-state conditions and make it impractical in many physiologically dynamic situations. The physiologic disturbances associated with massive resuscitation (e.g., hyperkalemia, hypocalcemia, hypomagnesemia, hypothermia) should be anticipated. Coagulation disturbances occur, especially when massive transfusion is accompanied by hypotension, hypothermia, or acidosis. Coagulation parameters should be measured with the loss of each one half of blood volume or after each 30-minute interval, whichever occurs first. Evaluation at blood volume intervals is relevant to the development of a strictly dilutional coagulopathy. The development of DIC, occurring because of tissue factor exposure or acidosis, however, is related more to the time lapsed than to the absolute volume lost or replaced.