Effects of the neurological wake-up test on clinical examination, intracranial pressure, brain metabolism and brain tissue oxygenation in severely brain-injured patients

Abstract

IntroductionDaily interruption of sedation (IS) has been implemented in 30 to 40% of intensive care units worldwide and may improve outcome in medical intensive care patients. Little is known about the benefit of IS in acutely brain-injured patients.MethodsThis prospective observational study was performed in a neuroscience intensive care unit in a tertiary-care academic center. Twenty consecutive severely brain-injured patients with multimodal neuromonitoring were analyzed for levels of brain lactate, pyruvate and glucose, intracranial pressure (ICP), cerebral perfusion pressure (CPP) and brain tissue oxygen tension (PbtO2) during IS trials.ResultsOf the 82 trial days, 54 IS-trials were performed as interruption of sedation and analgesics were not considered safe on 28 days (34%). An increase in the FOUR Score (Full Outline of UnResponsiveness score) was observed in 50% of IS-trials by a median of three (two to four) points. Detection of a new neurologic deficit occurred in one trial (2%), and in one-third of IS-trials the trial had to be stopped due to an ICP-crisis (> 20 mmHg), agitation or systemic desaturation. In IS-trials that had to be aborted, a significant increase in ICP and decrease in PbtO2 (P < 0.05), including 67% with critical values of PbtO2 < 20 mmHg, a tendency to brain metabolic distress (P < 0.07) was observed.ConclusionsInterruption of sedation revealed new relevant clinical information in only one trial and a large number of trials could not be performed or had to be stopped due to safety issues. Weighing pros and cons of IS-trials in patients with acute brain injury seems important as related side effects may overcome the clinical benefit.

ICU Management of Traumatic Brain Injury

“…It was concluded that since most of the patients experienced mild and transient elevations in ICP/CPP, repeated-wake-up trials are not precluded in these patients. In contrast, another prospective observational trial recently reported that among 54 sedative-interruption trials performed on 20 patients over 82 study days, one third of the trials required cessation owing to ICP crisis (ICP greater than 20 mmHg), agitation, or oxygen desaturation [52]. Critically low levels of PbO 2 (less than 20 mmHg) were observed in 67 % of the aborted trials.…”

Systematic and Comprehensive Literature Review of Publications on Direct Cerebral Oxygenation Monitoring

“…Catheters are generally placed in the right frontal lobe white matter in diffuse brain injury or for detecting global ischemia, or on the affected side in a hemispheric injury and by and at large remain in situ for as long as ICP measurements are required [197,206,229,[248][249][250][251][252]. During intraoperative aneurysm surgery and ICU treatment probe placement in the territory of the aneurysm harboring vessel has been advocated [44,62,63].…”

“…PbtO2 monitoring has been used to study the effects of the neurological wake-up test with interruption of sedation and analgesics (IS) [229]. The authors report that: "In IStrials that had to be aborted, a significant increase in ICP and decrease in pbtO2 (P < 0.05), including 67% with critical values of pbtO2 < 20 mmHg, a tendency to brain metabolic distress (P < 0.07) was observed" [229].…”

Critical Care Management Focused on Optimizing Brain Function After Cardiac Arrest

“…In brain-injured patients, interruption of sedation causes increased ICP. 106 Therefore, a wake-up test should be avoided during the first 24 h after ROSC. 107 It is suggested that the tapering of sedative infusions should not exceed 25% per day.…”