Relationship Between Plasma Adrenocorticotropin Hormone and Intensive Care Unit Survival in Early Traumatic Brain Injury

Abstract

Hypothalamic pituitary adrenal response has been recently evaluated in patients with traumatic brain injury (TBI) with different results. Our objective was to study this response and its relationship with outcome in the early stage after TBI. We conducted a prospective observational clinical study in the intensive care unit of a tertiary level university hospital. The study included 50 consecutive patients who suffered isolated TBI. Intracranial pressure (ICP) was measured by an intraparenchymal probe. All patients were sedated and mechanically ventilated. Second-level measures were provided as per protocol, when needed. We measured plasma adrenocorticotropin hormone (ACTH) levels, as well as baseline and stimulated serum cortisol after a high-dose corticotrophin stimulation test, within 2 days after TBI for all patients. Mean age was 36 +/- 18 (range 16-77) years. Forty-four (88%) were male. Median Glasgow Coma Scale score was 7. Mean ACTH was 15.4 +/- 19.8 pg/mL. Mean baseline cortisol was 14.8 +/- 9.0 microg/dL and mean stimulated cortisol was 27.1 +/- 7.3 microg/dL and 30.5 +/- 7.2 microg/dL at 30 and 60 minutes, respectively. Baseline and stimulated cortisol were not correlated with mortality. Logistic regression analysis revealed that, either plasma ACTH levels <9 pg/mL or lack of indication to provide second-level measures to control ICP were significant independent predictors of survival. The presence of a low plasma ACTH concentration at an early stage of TBI and lack of indication to provide second-level measures to control ICP were associated with a higher intensive care unit survival.