Monitoring the Relationship Between Changes in Cerebral Oxygenation and Electroencephalography Patterns During Cardiopulmonary Resuscitation: A Feasibility Study.

OBJECTIVES: To date, no studies have examined real-time electroencephalography and cerebral oximetry monitoring during cardiopulmonary resuscitation as markers of the magnitude of global ischemia. We therefore sought to assess the feasibility of combining cerebral oximetry and electroencephalography in patients undergoing cardiopulmonary resuscitation and further to evaluate the electroencephalography patterns during cardiopulmonary resuscitation and their relationship with cerebral oxygenation as measured by cerebral oximetry. DESIGN: Extended case series of in-hospital and out-of-hospital cardiac arrest subjects. SETTING: Tertiary Medical Center. PATIENTS: Inclusion criteria: Convenience sample of 16 patients undergoing cardiopulmonary resuscitation during working hours between March 2014 and March 2015, greater than or equal to 18 years. A portable electroencephalography (Legacy; SedLine, Masimo, Irvine, CA) and cerebral oximetry (Equanox 7600; Nonin Medical, Plymouth, MN) system was used to measure cerebral resuscitation quality. INTERVENTIONS: Real-time regional cerebral oxygen saturation and electroencephalography readings were observed during cardiopulmonary resuscitation. The regional cerebral oxygen saturation values and electroencephalography patterns were not used to manage patients by clinical staff. MEASUREMENTS AND MAIN RESULTS: In total, 428 electroencephalography images from 16 subjects were gathered; 40.7% (n = 174/428) were artifactual, therefore 59.3% (n = 254/428) were interpretable. All 16 subjects had interpretable images. Interpretable versus noninterpretable images were not related to a function of time or duration of cardiopulmonary resuscitation but to artifacts that were introduced to the raw data such as diaphoresis, muscle movement, or electrical interference. Interpretable data were able to be obtained immediately after application of the electrode strip. Seven distinct electroencephalography patterns were identified. Voltage suppression was commonest and seen during 78% of overall cardiopulmonary resuscitation time and in 15 of 16 subjects at some point during their cardiopulmonary resuscitation. Other observed patterns and their relative prevalence in relation to overall cardiopulmonary resuscitation time were theta background activity 8%, delta background activity 5%, bi frontotemporal periodic discharge 4%, burst suppression 2%, spike and wave 2%, and rhythmic delta activity 1%. Eight of 16 subjects had greater than one interpretable pattern. At regional cerebral oxygen saturation levels less than or equal to 19%, the observed electroencephalography pattern was exclusively voltage suppression. Delta background activity was only observed at regional cerebral oxygen saturation levels greater than 40%. The remaining patterns were observed throughout regional cerebral oxygen saturation categories above a threshold of 20%. CONCLUSIONS: Real-time monitoring of cerebral oxygenation and function during cardiac arrest resuscitation is feasible. Although voltage suppression is the commonest electroencephalography pattern, other distinct patterns exist that may correlate with the quality of cerebral resuscitation and oxygen delivery.

Cerebral oximetry versus end tidal CO2 in predicting ROSC after cardiac arrest.

STUDY OBJECTIVE: Both end tidal CO2 (ETCO2) and cerebral oxygen saturations (rSO2) have been studied to determine their ability to monitor the effectiveness of CPR and predict return of spontaneous circulation (ROSC). We compared the accuracy of ETCO2 and rSO2 at predicting ROSC in ED patients with out-of-hospital cardiac arrest (OHCA). METHODS: We performed a prospective, observational study of adult ED patients presenting in cardiac arrest. We collected demographic and clinical data including age, gender, presenting rhythm, rSO2, and ETCO2. We used receiver operating characteristic curves to compare how well rSO2 and ETCO2 predicted ROSC. RESULTS: 225 patients presented to the ED with cardiac arrest between 10/11 and 10/14 of which 100 had both rSO2 and ETCO2 measurements. Thirty three patients (33%) had sustained ROSC, only 2 survived to discharge. The AUCs for rSO2 and ETCO2 were similar (0.69 [95% CI, 0.59-0.80] and 0.77 [95% CI, 0.68-0.86], respectively), however, rSO2 and ETCO2 were poorly correlated (0.12, 95% CI, -0.08-0.31). The optimal cutoffs for rSO2 and ETCO2 were 50% and 20mm Hg respectively. At these cutoffs, ETCO2 was more sensitive (100%, 95% CI 87-100 vs. 48%, 31-66) but rSO2 was more specific (85%, 95% CI, 74-92 vs. 45%, 33-57). CONCLUSIONS: While poorly correlated, rSO2 and ETCO2 have similar diagnostic characteristics. ETCO2 is more sensitive and rSO2 is more specific at predicting ROSC in OHCA.