Optic Nerve Sheath Diameter Sonography for the Diagnosis of Increased Intracranial Pressure in Nontraumatic Neurocritically Ill Patients: a Diagnostic Accuracy Systematic Review and Meta-Analysis.

Abstract

Background: Optic nerve sheath diameter (ONSD) assessed by ultrasound is a feasible bedside method for increased intracranial pressure (IICP) diagnosis. However, most of the evidence relies on the population of patients with traumatic brain injury, with few data available on other populations. Consequently, its efficacy in nontraumatic critically ill patients remains underexplored. Our purpose was to examine the accuracy of ONSD ultrasonography for diagnosing IICP in nontraumatic neurocritically ill patients.

Methods: We conducted a systematic search of PubMed, Embase, and the Cochrane Library databases for comparative studies of adult nontraumatic critically ill patients that evaluated the accuracy of sonographic ONSD for IICP diagnosis compared with invasive or noninvasive reference standards. Two reviewers independently completed the search, data abstraction, and quality assessment with Quality Assessment of Diagnostic Accuracy Studies-2 tool. Heterogeneity was examined with I² statistics. We used a bivariate model of random effects to summarize pooled diagnostic odds ratio, sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and summary receiver operating characteristic.

Results: We included 18 observational studies, comprising 1,484 patients. Etiology of IICP was mixed, being composed of central nervous system infection, intracranial hemorrhage, acute ischemic stroke, aneurysmal subarachnoid hemorrhage, idiopathic intracranial hypertension, and hypoxic-ischemic brain injury. The pooled diagnostic odds ratio was 44.7 (95% confidence interval [CI] 22.5-80.1). Pooled sensitivity and specificity were 0.92 (95% CI 0.85-0.95) and 0.90 (95% CI 0.84-0.94), respectively, with a positive likelihood ratio of 6.19 (95% CI 4.4-8.5), and a negative likelihood ratio of 0.148 (95% CI 0.09-0.22). Summary receiver operating characteristic showed a calculated area under the curve of 0.925 (95% CI 0.84-0.927). Subgroup analysis of invasive and noninvasive reference standards showed similar accuracy of ultrasound ONSD for IICP diagnosis.

Conclusions: Ultrasound ONSD may be a potentially useful noninvansive tool for IICP diagnosis in patients with nontraumatic brain injury.