Can polyethylene glycol-20 K replace albumin for pre-hospital treatment of hemorrhagic shock when full resuscitation is unavailable?

A solution of high concentration albumin has been used for temporal volume expansion when timely resuscitation was unavailable following hemorrhagic shock. However, during prolonged hemorrhagic shock, cell edema and interstitial dehydration can occur and impede the volume expansion effect of albumin. Polyethylene glycol-20 K (PEG) can establish an osmotic gradient from swollen cells to capillary lumens and thus facilitate capillary fluid shift and volume expansion. We hypothesized that, with similar osmolality, 7.5% PEG elicits more rapid and profound compensatory responses following hemorrhagic shock than 25% albumin. Rats were randomized into three groups (n = 8/group) based on treatment: saline (vehicle), PEG (7.5%), and albumin (25%). Trauma was induced in anesthetized rats with muscle injury and fibula fracture, followed by pressure-controlled hemorrhagic shock (mean arterial pressure (MAP) = 55 mmHg) for 45 minutes. Animals then received an intravenous injection (0.3 ml/kg) of saline, PEG, or albumin. MAP, heart rate, blood gases, hematocrit, skeletal muscle capillary flow, renal blood flow (RBF), glomerular filtration rate (GFR), urinary flow, urinary sodium concentration, and mortality were monitored for another 2 hours. PEG and albumin both improved MAP, renal and capillary blood flow, and renal oxygen delivery, and decreased hyperkalemia, hyperlactatemia, hematocrit, and mortality (saline: 100% PEG: 12.5%; albumin: 38%) over saline treatment. Compared to albumin, PEG had a more rapid decrease in hematocrit, and more profound increases in MAP, diastolic pressure, RBF, GFR, and urinary flow. These results suggest PEG may be a better option than albumin for prolonged prehospital care of hemorrhagic shock.