Background and Purpose To identify a minimally-acceptable CPP threshold above which the risk of brain tissue hypoxia (BTH) and oxidative metabolic crisis is reduced for patients with SAH. Methods We studied thirty poor-grade SAH patients who underwent brain multimodality monitoring (3042 hours). Physiological measures were averaged over 60 minutes for each collected microdialysis sample. Metabolic crisis was defined as a lactate/pyruvate ratio (LPR) >40 with a brain glucose concentration ≤0.7 mmol/L. BTH was defined as PbtO2 <20 mm Hg. Outcome was assessed at 3 months with the modified Rankin Scale. Results Multivariable analyses adjusting for admission Hunt-Hess grade, intraventricular hemorrhage, systemic glucose, and end-tidal CO2 revealed that CPP ≤70 mm Hg was significantly associated with an increased risk of BTH (OR=2.0; 95%-CI: 1.2–3.3, P=0.007) and metabolic crisis (OR=2.1; 95%-CI 1.2–3.7, P=0.007). Death-or-severe-disability at 3 months was significantly associated with metabolic crisis (OR 5.4; 95%-CI: 1.8–16, P=0.002) and BTH (OR 5.1; 95%-CI: 1.2–23, P=0.03) after adjusting for admission Hunt-Hess grade. Conclusions Metabolic crisis and BTH are associated with mortality and poor functional recovery after SAH. CPP levels below 70 mm Hg was associated with metabolic crisis and BTH and may increase the risk of secondary brain injury in poor-grade SAH patients.

Increased TCD flow velocities imply only a mild incremental risk of DCI after SAH, with maximal sensitivity by day 8. Nearly 40% of patients with DCI never attained an mBFV more than 120 cm/s during the course of monitoring. Given the poor overall sensitivity of TCD, improved methods for identifying patients at high risk for DCI after SAH are needed.

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.