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

Raimund Helbok,Erich Schmutzhard,Jan Claassen,Michael J Schmidt,Morgan R Stuart,Kiwon Lee,Pedro Kurtz,Luis Fernandez,Sander E Connolly,Stephan A Mayer,Neeraj Badjatia

doi:10.1186/cc11880

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.

Highlights

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
Another important issue of interruption of sedation (IS)-trials is that the amount of sedatives and analgesics could be reduced [2,3]; the result of a recent meta-analysis of five randomized controlled trials comparing IS with no interruption in 699 critically ill patients challenges previous findings as a reduction in duration of mechanical ventilation, length of intensive care unit (ICU) stay or mortality could not be confirmed [7]
Interruption of sedation and analgesics was not attempted on 28 days (34%) due to Demographics and past medical history Age, y Gender

Summary

Introduction

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. Interruption of sedation trials (IS-trials) have been implemented in many surgical and medical ICUs after randomized controlled trials demonstrated that IS decreased the duration of mechanical ventilation, shortened the hospital stay and may, in combination with spontaneous breathing trials, improve outcome in medical intensive care patients [2,3,4,5,6]. Cerebral hypoperfusion and raised ICP may result in an imbalance of energy supply and demand especially for the injured brain and, aggravate the risk for metabolic distress and brain tissue hypoxia [10,11,12,13,14,15,16] These potential side-effects of IS-trials have not been investigated so far and may limit their clinical benefit in severely brain injured patients. We hypothesized that IS-trials may be harmful for these patients and examined the effects of IStrials on brain hemodynamic changes, brain tissue oxygen tension and metabolism using multimodal neuromonitoring devices in patients with acute brain injury

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