ICU Management of Traumatic Brain Injury

Traumatic brain injury induced temperature dysregulation: What is the role of β blockers?

BACKGROUND

Traumatic brain injury (TBI) is associated with sympathetic discharge that leads to posttraumatic hyperthermia (PTH). Beta blockers (ββ) are known to counteract overactive sympathetic discharge. The aim of our study was to evaluate the effect of ββ on PTH in critically-ill TBI patients.

METHODS

We performed retrospective cohort analysis of the Medical Information Mart for Intensive Care database. We included all critically ill TBI patients with head Abbreviated Injury Scale (AIS) score of 3 or greater and other body region AIS score less than 2 who developed PTH (at least one febrile episode [T > 38.3°C] with negative microbiological cultures (blood, urine, and bronchoalveolar lavage). Patients on preinjury ββ were excluded. Patients were stratified into (ββ+) and (ββ-) groups. Propensity score matching was performed (1:1 ratio) controlling for patient demographics, injury parameters and other medications that influence temperature. Outcomes were the number of febrile episodes, maximum temperature, and the time interval between febrile episodes. Multivariate linear regression was performed.

RESULTS

We analyzed 4,286 critically ill TBI patients. A matched cohort of 1,544 patients was obtained: 772 ββ + (metoprolol, 60%; propranolol, 25%; and atenolol, 15%) and 772 ββ-. Mean age was 63.4 ± 15.4 years, median head AIS score of 3 (3-4), and median Injury Severity Score of 10 (9-16). Patients in the ββ+ group had a lower number of febrile episodes (8 episodes vs. 12 episodes; p = 0.003), lower median maximum temperature (38.0°C vs. 38.5°C; p = 0.025), and a longer median time between febrile episodes (3 hours vs. 1 hour; p = 0.013). On linear regression, propranolol was found to be superior in terms of reducing the number of febrile episodes and the maximum temperature. However, there was no significant difference between the three ββ in terms of reducing the time interval between febrile episodes (p = 0.582).

CONCLUSION

Beta blockers attenuate PTH by decreasing the frequency of febrile episodes, increasing the time interval between febrile episodes, and reducing the maximum rise in temperature. ββ may be a potential therapeutic modality in PTH.

LEVEL OF EVIDENCE

Therapeutic, level IV.

The neuroprotective effect of quetiapine in critically ill traumatic brain injury patients

INTRODUCTION

Quetiapine is an atypical antipsychotic commonly used in critical care. Cellular and animal models demonstrated its novel anti-inflammatory properties in traumatic brain injury (TBI). Our study aimed to assess the effect of quetiapine on outcomes in critically ill TBI patients. We hypothesize that quetiapine improves neurological outcomes.

METHODS

The Multiparameter Intelligent Monitoring in Intensive Care database was queried, and all adult (age, ≥18 years) isolated TBI patients (extracranial Abbreviated Injury Scale, < 2) admitted to the intensive care unit for a period of >48 hours. Patients were stratified into quetiapine (+) and no-quetiapine (-) groups. Propensity score matching was performed (1:2 ratio). Outcome measures were intensive care unit length of stay, discharge Glasgow Coma Scale (GCS), and mortality. A subanalysis was performed for patients who underwent intracranial pressure (ICP) monitoring to ascertain the effect of quetiapine dose on ICP, and cerebral perfusion pressure (CPP). Survival curves and regression analyses were performed.

RESULTS

A matched cohort of (quetiapine, 116 vs. no-quetiapine, 232) patients was obtained. Mean ± SD age was 65 ± 21 years, median head Abbreviated Injury Scale was 3 (3-4), and median GCS was 10 (9-16). The median quetiapine dose given was 50 (25-125) mg. Patients who received quetiapine had lower mortality (17.2% vs. 27.6%; p = 0.03) and a higher median GCS at discharge (12 [11-14] vs. 11 [10-13]; p < 0.04) but no difference in intensive care unit length of stay (4.1 days vs. 4.7 days; p = 0.75) or discharge to skilled nursing facility (34.5% vs. 31.9%; p = 0.63). On subanalysis of patients who received quetiapine, 40% had ICP monitoring. Higher doses of quetiapine were independently associated with progressively lower ICP (β = -0.022 mm Hg/mg of quetiapine; p = 0.01) and higher CPP (β = 0.031 mm Hg/mg quetiapine; p = 0.01).

CONCLUSION

Quetiapine may decrease mortality and improve neurological outcomes in critically ill TBI patients. It has a dose-dependent effect to decrease ICP and increase CPP. Quetiapine may be a potential therapeutic modality in critically ill TBI patients, but further studies are required to explore these mechanisms.

LEVEL OF EVIDENCE

Systematic Review, level III.

Infrared pupillometry, the Neurological Pupil index and unilateral pupillary dilation after traumatic brain injury: implications for treatment paradigms

Pupillary dysfunction, a concerning finding in the neurologic examination of the patient with an acute traumatic brain injury often dictates the subsequent treatment paradigm. Patients were monitored closely with an infrared pupillometer, with NPi technology, for acute changes in pupillary function. NPi technology applies a scalar value to pupillary function. A retrospective chart review was performed of traumatic brain injury patients with acute unilateral pupillary dilation, admitted to Legacy Emanuel Medical Center’s NeuroTrauma Unit, Portland, OR, and followed as outpatients, between January 2012 and December 2013. Clinical exam findings of pupillary size, NPi scores, and brain Magnetic Resonance Imaging and Computed Tomography images were analyzed. Five traumatic brain injury patients were identified with unilateral pupillary dysfunction with long-term follow-up after the initial injury. Each patient was monitored closely in the trauma bay for neurological deterioration with a pupillometer and the clinical exam. Two patients underwent subsequent intracranial pressure monitoring based on a deteriorating clinical scenario, including consistent abnormal unilateral NPi scores. One patient with consistent abnormal NPi scores and an improved clinical exam did not undergo invasive interventions. Two patients showed early improvement in NPi scores correlating with the normalization of their pupillary reactivity. Anisocoria improved in all patients despite concurrent abnormal NPi scores. Magnetic Resonance Imaging and Computed Tomography imaging studies, with a focus on the third nerve, revealed focal abnormalities consistent with the clinical findings. A unilateral blown pupil and abnormal NPi score in a traumatic brain injury patient are not necessarily indicative of intracranial pressure issues, and must be correlated with the entire clinical scenario, to determine the etiology of the third nerve injury and direct potential therapeutic interventions. Early NPi score normalization suggests pupillary function may improve. We found that NPi scores, as a component of the clinical exam, provide a sensitive, noninvasive and quantitative means of following pupillary function acutely and chronically after a traumatic brain injury.