Resuscitation of hemorrhagic shock with normal saline versus lactated Ringer's: effects on oxygenation, extravascular lung water, and hemodynamics

Which type of fluid to use in the resuscitation from hemorrhagic shock, within and between crystalloids or colloids, is still a matter of debate. In this context, with respect to organ dysfunction, early detection of lung injury is widely considered of particular clinical importance. For these purposes, the transpulmonary thermodilution technique that enables one to assess extravascular lung water as a marker of pulmonary edema is applied in the clinical setting. In this issue of Critical Care, Phillips and colleagues describe that early resuscitation of hemorrhagic shock in pigs with two different crystalloid solutions - normal saline or Ringer's lactate - had little impact on oxygenation when the resuscitation volume was <250 ml/kg. Ringer's lactate had more favorable effects than normal saline, however, on extravascular lung water, pH, and blood pressure but not on oxygenation. Although several pathophysiological aspects remain unanswered, these data are interesting in so far as they indicate that clinically applied amounts of crystalloids per se do not negatively influence pulmonary function, while with larger amounts the type of fluid has different effects on the extent of fluid extravasation in the lungs.