Evaluating the utility of quantitative pupillometry in a neuro-critical care setting for the monitoring of intracranial pressure: A prospective cohort study.

INTRODUCTION: Assessment of the pupillary light reflex (PLR) is key in intensive care monitoring of neurosurgical patients, particularly for monitoring intracranial pressure (ICP). Quantitative pupillometry using a handheld pupillometer is a reliable method for PLR assessment. However, many variables are derived from such devices. We therefore aimed to assess the performance of these variables at monitoring ICP. METHODS: Sedated patients admitted to neurocritical care in a tertiary neurosurgical centre with invasive ICP monitoring were included. Hourly measurement of ICP, subjective pupillometry (SP) using a pen torch device, and quantitative pupillometry (QP) using a handheld pupillometer were performed. RESULTS: 561 paired ICP, SP and QP pupillary observations from nine patients were obtained (1122 total pupillary observations). SP and QP had a moderate concordance for pupillary size (κ=0.62). SP performed poorly at detecting pupillary size changes (sensitivity=24%). In 40 (3.6%) observations, SP failed to detect a pupillary response whereas QP did. Moderate correlations with ICP were detected for maximum constriction velocity (MCV), dilation velocity (DV), and percentage change in pupillary diameter (%C). Discriminatory ability at an ICP threshold of >22 mmHg was moderate for MCV (AUC=0.631), DV (AUC=0.616), %C (AUC=0.602), and pupillary maximum size (AUC=0.625). CONCLUSION: QP is superior to SP at monitoring pupillary reactivity and changes to pupillary size. Although effect sizes were moderate to weak across assessed variables, our data indicates MCV and %C as the most sensitive variables for monitoring ICP. Further study is required to validate these findings and to establish normal range cut-offs for clinical use.

A Systematic Review and Meta-Analysis of the Effectiveness of Surgical Decompression in Treating Patients with Malignant Middle Cerebral Artery Infarction.

BACKGROUND: Malignant infarction of the middle cerebral artery (MCI) is life threatening. It is associated with a mortality as high as 80%, and survival often at the expense of serious disability. Limited success of medical therapies has resulted in decompressive craniectomy (DC) being increasingly used as a treatment for MCI, although evidence of its efficacy is inconclusive. In this study, the efficacy of DC in improving survival, or survival free of severe disability, was assessed. METHODS: A meta-analysis was performed to approximate the efficacy of DC for treating MCI, considering age and time to surgery. A systematic literature review was conducted on Medline, Embase, and Cochrane library databases to August 1, 2018. Death and severe disability at 3, 6, 12, and 36 months follow-up were assessed, comparing best medical therapy with DC. RESULTS: 18 studies were eligible for inclusion and represented 987 individuals who received DC. Nine of these were randomized controlled trials (RCTs) (n = 374 DC). Early DC (<48 hours from onset of stroke) reduced mortality (odds ratio [OR] = 0.18, 95% confidence interval [CI] = 0.11, 0.29; P < 0.00001) but not unfavourable outcome (modified Rankin Scale [mRS] >4) (OR = 1.38, 95% CI = 0.47, 4.11; P = 0.56) at 12 months follow-up. This survival benefit was maintained regardless of age. CONCLUSION: Early DC reduces mortality but does not appear to improve favourable outcomes in patients younger or older than 60 years after MCI. RCTs incorporating quality of life assessments are warranted for MCI patients, in addition to defining the optimal timing and benefits of DC in older patients.