A 22-year-old man is brought to the emergency department by ambulance after sustaining a gunshot wound to the abdomen during a home invasion. The event occurred 45 minutes prior to arrival. Because of hypotension, paramedics administered 1 L of normal saline en route to the emergency department. On arrival, blood pressure is 98/62 mm Hg, pulse is 120/min, and respirations are 22/min. The patient is awake and moaning in pain. The lungs are clear to auscultation bilaterally, and heart sounds are normal. One bullet wound is noted in the left upper quadrant. The abdomen is tender and distended. The patient is moving all his extremities, but they are cool and clammy. Focused Assessment with Sonography for Trauma examination shows free fluid in the abdomen. Continuation of additional normal saline fluid boluses in this patient would likely result in which of the following?
This patient with penetrating abdominal trauma has signs of hemorrhagic shock (eg, hypotension, tachycardia, cool extremities) and, likely, ongoing hemorrhage (eg, free intraperitoneal fluid on Focused Assessment with Sonograph for Trauma). Such patients once received early, aggressive crystalloid (eg, normal saline) resuscitation to restore intravascular volume and normal blood pressure. Now, balanced resuscitation (aka, damage-control resuscitation) is used; it includes the following measures:
Limiting use of crystalloids (eg, ≤1 L), which dilute existing coagulation (eg, clotting) factors and platelets, thereby increasing coagulopathy
Replacing lost intravascular volume with blood products (rather than crystalloids), transfused in a ratio similar to that of whole blood (eg, 1:1:1 ratio of packed red blood cells/plasma/platelets)
Permitting hypotension (ie, permissive hypotension) to limit ongoing hemorrhage and/or prevent clot disruption and rebleeding
With balanced resuscitation, blood products are administered only as needed to maintain a blood pressure (eg, mean arterial pressure ~65 mm Hg) sufficient for tissue perfusion, until definitive hemorrhage control (eg, surgical intervention) can be achieved.
In addition to coagulopathy, aggressive crystalloid resuscitation has been associated with the following detrimental effects:
Hypothermia: Room temperature fluids are cooler than body temperature and can cause hypothermia (which worsens coagulopathy), especially when administered in large volumes (Choice B).
Acidosis: Large volumes of rapidly administered normal saline can cause non–anion gap hyperchloremic metabolic acidosis (vs alkalosis), which can further worsen the performance of coagulation factors (Choice D).
Increased mortality: Overuse of crystalloids worsens the "lethal triad" (hypothermia, acidosis, coagulopathy) already present in severely injured trauma patients, increasing the risk for mortality.
(Choice A) The trauma-induced inflammatory response can cause capillary leakage and diffuse pulmonary edema, sometimes resulting in acute respiratory distress syndrome (ARDS). Crystalloids have been shown to cause a dose-dependent increase (vs decrease) in ARDS; they have a lower oncotic pressure than blood and can leak more easily into the pulmonary interstitium.
Educational objective:
Large-volume crystalloid resuscitation increases coagulopathy, hypothermia, and mortality in trauma patients. Balanced resuscitation, which restricts crystalloid use and uses blood products to maintain a blood pressure just sufficient for tissue perfusion (ie, permissive hypotension) until hemorrhage is controlled, can decrease these adverse effects.