Hernández-Durán S, Meinen L, Rohde V, von der Brelie C. Invasive Monitoring of Intracranial Pressure After Decompressive Craniectomy in Malignant Stroke. Stroke. 2021 Jan;52(2):707-711. doi: 10.1161/STROKEAHA.120.032390. Epub 2020 Dec 4.
Reviewed by Shannon Hextrum, MD
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Background: Decompressive hemicraniectomy (DC) improves mortality in malignant cerebral infarction (MCI). There is little evidence to guide the use of intracranial pressure (ICP) monitoring in the management of MCI before or after DC. This study examines the utility of postoperative ICP monitoring in DC for MCI and aims to define ICP thresholds for treatment considerations.
Methods: This retrospective, observational study included patients receiving DC for MCI with ICPs recorded hourly during 72-hours post-op. Pressure monitoring occurred via intraparenchymal ICP probes, which were placed at the time of DC in the ipsilateral frontal lobe. All patients received deep sedation per institutional protocol for 72 hours targeting Richmond Agitation and Sedation Scale (RASS) -5, and ventilation targeted hypocapnia (PaCO2 34-38 mm Hg). Invasive arterial pressure monitoring was utilized in all patients, and goal cerebral perfusion pressure (CPP) was >60 mmHg. ICPs > 20 mmHg were treated per guidelines. External ventricular drainage was pursued if conservative treatments failed. Sedation was decreased after 72 hours, if patients demonstrated stable ICPs and head CT at that time.
Results: 111 patients were studied, and patients were grouped by mortality status and age (<60 year, ≥ 60 year) for comparison of baseline characteristics. The mean NIHSS at presentation was 15 for those patients who survived vs. 17 for patients who died, which was not a statistically significant difference. Time to DC was not significantly different between the group of survivors (36 hour) and deceased (42 hours), nor was mean presentation GCS between these groups. Baseline clinic characteristics, radiologic features (ASPECTS score, midline shift), and interventions (e.g., time to DC, EVD placement and other treatments) did not predict mortality in a multiple regression analysis. Mean ICP was predictive of mortality in the entire group as well as in the subgroup <60 years. Using a receiver operating characteristic (ROC) analysis, a threshold of 10 mm Hg demonstrated 70% sensitivity and 97% specificity for mortality in the whole sample. When analyzing the group of patients <60 years, mean ICP > 10 mm Hg was 100% sensitive and 83 % specific for mortality.
Commentary: This study examined mean ICPs in the first 72 hours after DC and established an ICP threshold of 10 mm Hg as a predictor of mortality in this sample of patients receiving DC for MCI. Drawbacks to this analysis include a relatively small sample size, retrospective study design, and lack of additional outcome variables aside from mortality. All patients received deep sedation (RAAS of -5) for 72 hours after DC using an institutional protocol. Such sedation targets may not be warranted in routine clinical practice. Despite such limitations, this analysis is compelling given the relatively low ICP threshold that was determined. Intracranial hypertension is generally defined as ICP ≥ 20 mm Hg, as seen in literature for traumatic brain injury. This study suggests that such a threshold may be too high for patients undergoing DC for MCI. Further investigations into cerebral compliance and ICP after DC for MCI is warranted.