Use and effect of vasopressors after pediatric traumatic brain injury

Vasopressors are commonly used to increase mean arterial blood pressure (MAP) and cerebral perfusion pressure (CPP) after traumatic brain injury (TBI), but there are few data comparing vasopressor effectiveness after pediatric TBI.

To determine which vasopressor is most effective at increasing MAP and CPP in children with moderate-to-severe TBI.

After institutional review board approval, we performed a retrospective cohort study of children 0-17 years old admitted to a level 1 trauma center (Harborview Medical Center, Seattle, Wash., USA) between 2002 and 2007 with moderate-to-severe TBI who received a vasopressor to increase blood pressure. Baseline demographic and physiologic characteristics and hourly physiologic monitoring for 3 h after having started a vasopressor were abstracted. We evaluated differences in MAP and CPP at 3 h after initiation of therapy between phenylephrine, dopamine and norepinephrine among patients who did not require a second vasopressor during this time. Multivariate linear regression was used to adjust for age, gender, injury severity score and baseline MAP or CPP and to cluster by subject.

Eighty-two patients contributed data to the entire dataset. The most common initial medication was phenylephrine for 47 (57%). Patients receiving phenylephrine and norepinephrine tended to be older than those receiving dopamine and epinephrine. Thirteen (16%) of the patients received a second vasopressor during the first 3 h of treatment and were thus not included in the regression analyses; these patients received more fluid resuscitation and exhibited higher in-hospital mortality (77 vs. 32%; p = 0.004) compared to patients receiving a single vasopressor. The norepinephrine group exhibited a 5 mm Hg higher MAP (95% CI: -4 to 13; p = 0.31) and a 12 mm Hg higher CPP (95% CI: -2 to 26; p = 0.10) than the phenylephrine group, and a 5 mm Hg higher MAP (95% CI: -4 to 15; p = 0.27) and a 10 mm Hg higher CPP (95% CI: -5 to 25; p = 0.18) than the dopamine group. However, in post hoc analysis, after adjusting for time to start of vasopressor, hypertonic saline and pentobarbital, the effect on MAP was lost, but the CPP was 8 mm Hg higher (95% CI: -10 to 25; p = 0.39) than in the phenylephrine group, and 5 mm Hg higher (95% CI: -14 to 24; p = 0.59) than in the dopamine group.

Vasopressor use varied by age. While there was no statistically significant difference in MAP or CPP between vasopressor groups, norepinephrine was associated with a clinically relevant higher CPP and lower intracranial pressure at 3 h after start of vasopressor therapy compared to the other vasopressors examined.