Cerebral Oximetry for Detecting High-mortality Risk Patients with Cryptococcal Meningitis

Abstract

Background. Cryptococcus is the commonest cause of adult meningitis in Africa, with 50%-70% experiencing increased intracranial pressure. Cerebral oximetry is a noninvasive near-infrared spectroscopy technology to monitor percent regional cerebral tissue oxygenation (rSO(2)). We assessed if cerebral oximetry predicts meningitis mortality.Methods. We performed cerebral oximetry within 14 days of cryptococcal meningitis diagnosis on 121 Ugandans from April 2016 to September 2017. We evaluated baseline rSO(2) association with mortality by multivariable logistic regression and correlation with other clinical factors. We compared groups formed by initial rSO(2) < 30% vs >= 30% for longitudinal change with mixed effects models. We measured change in % rSO(2) before and after lumbar puncture (LP).Results. The median initial rSO(2) (interquartile range) was 36% (29%-42%), and it was < 30% in 29% (35/121). For 30-day mortality, the unadjusted odds ratio (per 5% increase in rSO(2)) was 0.73 (95% confidence interval [CI], 0.58 to 0.91; P = .005). Those with initial rSO(2) < 30% had 3.4 (95% CI, 1.5 to 8.0) higher odds of 30-day mortality than those with initial rSO(2) = 30%. Hemoglobin correlated with initial rSO(2) (rho = .54; P < .001), but rSO(2) did not correlate with pulse oximetry, intracranial pressure, cerebral perfusion pressure, or quantitative cerebrospinal fluid culture, and rSO(2) was unchanged pre/post-lumbar punctures. The longitudinal rSO(2) measurements change was 15% (95% CI, 12% to 18%) lower in the group with initial rSO(2) < 30%.Conclusions. Individuals with cryptococcal meningitis and low cerebral oximetry (rSO(2) < 30%) have high mortality. Cerebral oximetry may be useful as a prognostic marker of mortality. Targeted interventions to improve rSO(2) should be tested in trials to try to decrease mortality in meningitis.