Optimal cerebral perfusion pressure in patients with intracerebral hemorrhage: an observational case series

Abstract

IntroductionCurrent guidelines for spontaneous intracerebral hemorrhage (ICH) recommend maintaining cerebral perfusion pressure (CPP) between 50 and 70 mmHg, depending on the state of autoregulation. We continuously assessed dynamic cerebral autoregulation and the possibility of determination of an optimal CPP (CPPopt) in ICH patients. Associations between autoregulation, CPPopt and functional outcome were explored.MethodsIntracranial pressure (ICP), mean arterial pressure (MAP) and CPP were continuously recorded in 55 patients, with 38 patients included in the analysis. The pressure reactivity index (PRx) was calculated as moving correlation between MAP and ICP. CPPopt was defined as the CPP associated with the lowest PRx values. CPPopt was calculated using hourly updated of 4 hour windows. The modified Rankin Scale (mRS) was assessed at 3 months and associations between PRx, CPPopt and outcomes were explored using Pearson correlation and Fisher’s exact test. Multivariate stepwise logistic regression models were calculated including standard outcome predictors along with percentage of time with PRx >0.2 and percentage of time within the CPPopt range.ResultsAn overall PRx indicating impairment of pressure reactivity was found in 47% of patients (n = 18). The mean PRx and the time spent with a PRx > 0.2 significantly correlated with mRS at 3 months (r = 0.50, P = 0.002; r = 0.46, P = 0.004). CPPopt was calculable during 57% of the monitoring time. The median CPP was 78 mmHg, the median CPPopt 83 mmHg. Mortality was lowest in the group of patients with a CPP close to their CPPopt. However, for none of the CPPopt variables a significant association to outcome was found. The percentage of time with impaired autoregulation and hemorrhage volume were independent predictors for acceptable outcome (mRS 1 to 4) at three months.ConclusionsFailure of pressure reactivity seems common following severe ICH and is associated with unfavorable outcome. Real-time assessment of CPPopt is feasible in ICH and might provide a tool for an autoregulation-oriented CPP management. A larger trial is needed to explore if a CPPopt management results in better functional outcomes.

Autoregulation monitoring and outcome prediction in neurocritical care patients: Does one index fit all?

“…Therefore, additional information such as the time duration of increasing indexes was not available. Recently this parameter was shown to correlate with 3-month outcome [ 16 ]. In our study we used averaged values of Mx and PRx and correlated these values with outcome.…”

“…Deviation of CPP from CPPopt was formerly reported to be associated with bad outcome [ 15 , 16 ]. However, we could not include this parameter in our analysis.…”

Novel index for predicting mortality during the first 24 hours after traumatic brain injury

“…Additionally, the extent of hypoperfusion measured by CPPopt was defined as the duration of when CPPopt -CPP (DCPP) > 5 mm Hg. 13 The PRx for identifying the CPPopt was determined by the moving Pearson's correlation coefficient, which was calculated using the 10-second averaged ABP and ICP in a 300-second window. 10 CPPopt was calculated as per the methods provided in a previous study.…”

“…It should be noted that while previous studies have reported the association between outcome and hypoperfusion events, the studies utilized the percentage of time of such events in entire, prolonged recordings. 2,13,14,20,21,28,31 In practice, one cannot predict how long a patient will be monitored; thus, the generalizability of previous findings in a prospective setting could be quite low. In contrast, dHP provides the cumulative duration of hypoperfusion events; hence, dHP should be better suited for future prospective studies.…”

“…21,31 The CPPopt can provide the means to determine the patient-specific adequate level of CPP and may be useful in the prognosis of TBI and hemorrhagic strokes. 13,28 However, the PRx, which is the basis of the CPPopt, has an important limitation: the parameter may not function as intended if the intracranial compliance is low. 1,26 This is problematic because during neurocritical care of TBI patients, the ICP is often aggressively managed.…”