Prehospital fluid resuscitation: What type, how much, and controversies

Overview

Fluid resuscitation is a vital treatment in the care of hypotensive trauma patients suffering from shock. Restoration of effective circulating blood volume improves oxygen delivery, thereby diminishing the untoward effects of shock at the cellular and organ level. The logistics of prehospital care, however, make this challenging. Consideration must be given to variables such as vascular access and the value of the resuscitation fluid. Debate persists concerning the type, amount, and the timing of fluid repletion to malperfused patients. The purpose of this chapter is to provide insight regarding the prehospital fluid resuscitation of those individuals.

Epidemiology

Trauma is the leading cause of civilian death in Americans aged less than 45 years and the fourth leading cause of death in the United States for all ages; hemorrhagic shock is the primary physiologic defect leading to death. But injured patients also suffer from other pathophysiology resulting in malperfusion. Namely, obstructive shock in the form of cardiac tamponade and tension pneumothorax and neurogenic shock resulting from spinal cord injury. Importantly, all of these shock states stand to benefit on some level from increased cardiac preload that might result from expansion of the effective circulating volume. Hypovolemia develops not only from blood loss but also diffuse capillary-endothelial leak, shifting fluids from the intravascular to the interstitial space. This loss of circulating blood volume, and the attendant hypoperfusion, potentially lead to multiple organ dysfunction, failure, and death.

The mainstay of resuscitation teaching was the initiation of a 2-L crystalloid fluid bolus to hypotensive injured patients en route to definitive trauma care. This paradigm, however, was called into question by research conducted by Bickell et al demonstrating decreased mortality among patients who received a more restrictive crystalloid resuscitation regimen. Currently, a majority of U.S. states use a systolic blood pressure greater than or equal to 90 as the volume resuscitation goal, with nine states in particular capping the maximum dose at 2 L without additional medical command. Several studies have attempted to quantify typical prehospital fluid volumes with mixed results. Most data suggest that the average prehospital intravenous fluid resuscitation ranges from 500 to 750 mL, but this can vary widely based on geography and mode of prehospital transport.

Diagnosis and management

Overwhelmingly, the prehospital care provided to injured patients is modeled on the Prehospital Trauma Life Support course, which focuses on prompt identification and treatment of life-threatening problems. While traditional teaching draws attention to circulation (inclusive of bleeding and repletion of lost blood volume) after the assessment of the patient’s airway and breathing, hence the traditional “ABC,” more recent practices have prioritized cessation of massive bleeding prior to addressing issues with the airway and breathing. This is paramount because the sequelae of sedation, paralysis, and the initiation of positive pressure ventilation (in the setting of hemorrhagic shock) is decreased central venous pressure and cardiac output. This can result in cardiovascular collapse and death. In that regard, fluid resuscitation must be addressed early in the course of the assessment to preempt the complications of hypovolemia.

Resuscitation fluids