Change in cerebral perfusion of patients with coma after treatment with right median nerve stimulation and hyperbaric oxygen

Background. Survival rates after acute brain injury have improved, but persistent coma continues to be a major clinical problem. Objective. We analyzed changes in cerebral perfusion after treatment with right median nerve stimulation (MNS) or MNS with hyperbaric oxygen (MNS + HBO), two noninvasive therapies that have shown promise in this patient population. Methods. During the period this series of patients was treated, decision-makers were offered the option of MNS for six weeks (continued for maximum of three months if patient responded) or MNS + HBO (HBO given during the first six weeks of MNS). Results. Of 41 patients, 14 received MNS only and 27 received MNS + HBO. Pre- and posttreatment single photon emission computed tomography scans showed increased cerebral perfusion in 29 patients, with perfusion unchanged in nine patients and decreased in three patients. A total of 25 patients improved in one or more clinical measures, with 13 regaining consciousness. With univariate analysis, the odds ratio for improvement with MNS + HBO relative to MNS was 4.40 (95% confidence intervals: 1.06-18.36). Multivariate analysis indicated that MNS + HBO was significantly related to increased cerebral perfusion compared with MNS alone (odds ratio = 8.44, 95% confidence intervals: 1.34-52.97). Conclusion. The combination of MNS + HBO is more likely to result in improved cerebral perfusion than MNS alone. Randomized prospective trials evaluating MNS, especially with adjunct HBO, are needed to clarify clinical indications and most effective treatment schemes.