Early neurological wake-up test in intubated brain-injured patients: A long-term, single-centre experience

In prehospital setting, a severe traumatic brain injury (TBI) requires tracheal intubation, sedation and mechanical ventilation pending the initial imagery. An early neurological wake-up test (ENWT), soon after the initial imaging assessment, allows a rapid neurological reassessment. This strategy authorises an initial clinical examination of reference with which will be compared the later examinations. The main objective of this study was to describe the characteristics of the patients who underwent an ENWT, and to determine its causes of failure.

We conducted a retrospective, observational, single-centre study including all intubated TBI admitted in the trauma centre. An ENWT was defined as cessation of sedation within 24h after TBI. Data concerning patient characteristics, CT-scan results, and outcomes were extracted from a prospective register of all intubated TBI admitted in the ICU. Characteristic of ENWT and causes of failure were retrieved from patient files. A multivariate logistic regression model was developed to determine the risk factors of ENWT failure.

During 7 years, 242 patients with intubated TBI were included. An ENWT was started in 96 patients, for an overall rate at 40%. The ENWT was stopped in 38 patients (39.5%), mostly due to neurological deterioration in 27 cases (71%) or respiratory distress in 10 cases (26%). Significant predictors of ENWT failure were: the presence of subdural hematoma with a thickness >5mm on first imagery (OR=3.2; 95%CI [1.01-10.28]), and an initial GCS score <5 (OR=7.4; 95%CI [1.92-28.43]). Prevalence of poor outcome at 1year was lesser in patients with successful ENWT compared to those with failure or absence of ENWT: 4% vs. 48% and 49% (p<0.0001).

The ENWT is achieved in 40% of patients, with a success rate of 60.5%. In presence of a subdural hematoma with a thickness >5mm or an initial GCS score <5, an ENWT failure may be expected.