Pre-hospital portable monitoring of cerebral regional oxygen saturation (rSO(2)) in seven patients with out-of-hospital cardiac arrest

BACKGROUND: In recent years, measurement of cerebral regional oxygen saturation (rSO(2)) has attracted attention during resuscitation. However, serial changes of cerebral rSO(2) in pre-hospital settings are unclear. The objective of this study was to clarify serial changes in cerebral rSO(2) of patients with out-of-hospital cardiac arrest (OHCA) in the pre-hospital setting. METHODS: We recently developed a portable rSO(2) monitor that is small (170 × 100 × 50 mm in size and 600 g in weight) enough to carry in pre-hospital settings. The sensor is attached to the patient’s forehead by the ELT (Emergency Life-saving Technician), and it monitors rSO(2) continuously. RESULTS: From June 2013 through August 2014, serial changes in cerebral rSO(2) in seven patients were evaluated. According to the results of the serial changes in rSO(2), four patterns of rSO(2) change were found, as follows. Type 1: High rSO(2) (around about 60 %) type (n = 1). Initial electrocardiogram was ventricular fibrillation and ROSC (return of spontaneous circulation) could be diagnosed in pre-hospital setting. Her outcome at discharge was Good Recovery (GR). Type 2: Low rSO(2) (around about 45–50 %) type (n = 3). They did not get ROSC even once. Type 3: Gradually decreasing rSO(2) type (n = 2): ROSC could be diagnosed in hospital, but not in pre-hospital setting. Their outcomes at discharge were not GR. Type 4: other type (n = 1). In this patient with ROSC when ELT started cerebral rSO(2) measurement, cerebral rSO(2) was 67.3 % at measurement start, it dropped gradually to 54.5 %, and then rose to 74.3 %. The cerebral oxygenation was impaired due to possible cardiac arrest again, and after that, ROSC led to the recovery of cerebral blood flow. CONCLUSION: We could measure serial changes in cerebral rSO(2) in seven patients with OHCA in the pre-hospital setting. Our data suggest that pre-hospital monitoring of cerebral rSO(2) might lead to a new resuscitation strategy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13104-016-2239-4) contains supplementary material, which is available to authorized users.