Characterizing vasopressin and other vasoactive mediators released during resuscitation of trauma patients

BACKGROUND: We sought to perform the first characterization of vasopressin and other vasoactive mediators released during resuscitation of hypotensive trauma patients. METHODS: This institutional review board-approved study was conducted under waiver of consent. Adults with clinical evidence of acute traumatic injury and systolic blood pressure less than or equal to 90 mm Hg within 1 hour of arrival were evaluated at our Level I trauma center. Two hundred three patients were screened with 50 enrolled from February 2010 to February 2011. Demographic information was also collected. Blood samples were obtained at 0, 30, 60, 90, 120, and 240 minutes after arrival, and assays were performed for vasopressin, angiotensin II, epinephrine, and cortisol. We assessed the significance of variation in these vasoactive mediators with injury and transfusion of more than 600 mL, with adjustment for time using repeated-measures linear models in log units. RESULTS: We found that vasopressin (p = 0.005) and epinephrine (p = 0.01) increased significantly with injury, while angiotensin (p = 0.60) and cortisol (p = 0.46) did not and that vasopressin (p < 0.001) and epinephrine (p = 0.004) increased significantly in patients requiring transfusion of more than 600 mL but angiotensin II (p = 0.11) and cortisol (p = 0.90) did not. Relatively low levels of vasopressin (<30 pg/mL) were observed at least once during the first 2 hours in 88% of trauma patients, and abnormally low epinephrine levels (<100 pg/mL) were observed at least once during the first 2 hours in 18% of trauma patients. CONCLUSION: This is the first clinical trial to serially evaluate vasopressin and other vasoactive mediators following trauma during the resuscitation phase. Vasopressin, in particular, and epinephrine seem to be the key mediators produced in the human response to severe injury. A deficiency of vasopressin may contribute to intractable shock after trauma.