Hyperosmotic solutions (HS) and hyperosmotic–hyperoncotic solutions (HHS) containing 7.2 -7.5 % NaCl have proven beneficial for the resuscitation of patients suffering from hypovolemic shock, especially after trauma. In recent years they have also been used perioperatively for fluid replacement in patients undergoing cardiopulmonary bypass, aortic aneurysm surgery, and those with sepsis.
Nearly all investigators infused HS/HHS more slowly (typically over 20 minutes) than during the resuscitation from hemorrhagic shock (5 minutes). Nevertheless they still could demonstrate that application of HS/HHS is efficient. It was shown that an infusion of HS/HHS results in an rapid increase in cardiac filling pressures with a concomitant increase in cardiac output and oxygen delivery. In some high risk patients it seems advisable to closely monitor the cardiac response to fluid loading with HS/HHS and best to titrate the infused volume against the changes in pulmonary capillary wedge pressure. Perioperative fluid balance was less positive than after conventional fluid resuscitation, an effect that often lasted into the postoperative period. Some studies could show an improvement in pulmonary function; however, others found no change. In septic patients filling pressures, cardiac output, and oxygen delivery were increased. These effects were, however, of short duration. The recently demonstrated positive effects of HS/HHS on the immune function may be of particular interest for this patient population, but they still must be confirmed in a clinical trial. This also holds true for the positive microcirculatory effects of HS/HHS, which is nearly always impaired after both cardiopulmonary bypass and in sepsis. Ultimately, however, demonstrated improvement in morbidity and mortality, yet to be shown, will promote the widespread clinical use of these solutions.
Department of Anaesthesiology, Ludwig Maximilians University, Munich, Germany
Correspondence to Frank Christ, MD, Department of Anaesthesiology, Ludwig Maximilians University, 81366 Munich, Germany