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Despite improvements in cardiopulmonary resuscitation (CPR), survival and neurologic recovery after cardiac arrest remain very poor because of the impact of severe ischemia and subsequent reperfusion injury. As the likelihood of survival and favorable neurologic outcome decreases with increasing severity of ischemia during CPR, developing methods to measure the magnitude of ischemia during resuscitation, particularly cerebral ischemia, is critical for improving overall outcomes. Cerebral oximetry, which measures regional cerebral oxygen saturation (rSO2) by near‐infrared spectroscopy, has emerged as a potentially beneficial marker of cerebral ischemia during CPR. In numerous preclinical and clinical studies, higher rSO2 during CPR has been associated with improved cardiac arrest survival and neurologic outcome. In this narrative review, we summarize the scientific rationale and validation of cerebral oximetry across populations and pathophysiologic states, discuss the evidence surrounding its use to predict return of spontaneous circulation, rearrest, and neurologic outcome, and provide suggestions for incorporation of cerebral oximetry into CPR practice. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objectives: Cardiac arrest is associated with morbidity and mortality because of cerebral ischemia. Therefore, we tested the hypothesis that higher regional cerebral oxygenation during resuscitation is associated with improved return of spontaneous circulation, survival, and neurologic outcomes at hospital discharge. We further examined the validity of regional cerebral oxygenation as a test to predict these outcomes.Design: Multicenter prospective study of in-hospital cardiac arrest.Setting: Five medical centers in the United States and the United Kingdom.Patients: Inclusion criteria are as follows: in-hospital cardiac arrest, age 18 years old or older, and prolonged cardiopulmonary resuscitation greater than or equal to 5 minutes. Patients were recruited consecutively during working hours between August 2011 and September 2014. Survival with a favorable neurologic outcome was defined as a cerebral performance category 1-2.Interventions: Cerebral oximetry monitoring.Measurements and Main Results: Among 504 in-hospital cardiac arrest events, 183 (36%) met inclusion criteria. Overall, 62 of 183 (33.9%) achieved return of spontaneous circulation, whereas 13 of 183 (7.1%) achieved cerebral performance category 1-2 at discharge. Higher mean ± SD regional cerebral oxygenation was associated with return of spontaneous circulation versus no return of spontaneous circulation (51.8% ± 11.2% vs 40.9% ± 12.3%) and cerebral performance category 1-2 versus cerebral performance category 3-5 (56.1% ± 10.0% vs 43.8% ± 12.8%) (both p < 0.001). Mean regional cerebral oxygenation during the last 5 minutes of cardiopulmonary resuscitation best predicted the return of spontaneous circulation (area under the curve, 0.76; 95% CI, 0.69-0.83); regional cerebral oxygenation greater than or equal to 25% provided 100% sensitivity (95% CI, 94-100) and 100% negative predictive value (95% CI, 79-100); regional cerebral oxygenation greater than or equal to 65% provided 99% specificity (95% CI, 95-100) and 93% positive predictive value (95% CI, 66-100) for return of spontaneous circulation. Time with regional cerebral oxygenation greater than 50% during cardiopulmonary resuscitation best predicted cerebral performance category 1-2 (area under the curve, 0.79; 95% CI, 0.70-0.88). Specifically, greater than or equal to 60% cardiopulmonary resuscitation time with regional cerebral oxygenation greater than 50% provided 77% sensitivity (95% CI,:46-95), 72% specificity (95% CI, 65-79), and 98% negative predictive value (95% CI, 93-100) for cerebral performance category 1-2.Conclusions: Cerebral oximetry allows real-time, noninvasive cerebral oxygenation monitoring during cardiopulmonary resuscitation. Higher cerebral oxygenation during cardiopulmonary resuscitation is associated with return of spontaneous circulation and neurologically favorable survival to hospital discharge. Achieving higher regional cerebral oxygenation during resuscitation may optimize the chances of cardiac arrest favorable outcomes. [ABSTRACT FROM AUTHOR]

Objective: A major hurdle limiting the ability to improve the quality of resuscitation has been the lack of a noninvasive real-time detection system capable of monitoring the quality of cerebral and other organ perfusion, as well as oxygen delivery during cardiopulmonary resuscitation. Here, we report on a novel system of cerebral perfusion targeted resuscitation. Design: An observational study evaluating the role of cerebral oximetry (Equanox; Nonin, Plymouth, MI, and Invos; Covidien, Mansfield, MA) as a real-time marker of cerebral perfusion and oxygen delivery together with the impact of an automated mechanical chest compression system (Life Stat; Michigan Instruments, Grand Rapids, Ml) on oxygen delivery and return of spontaneous circulation following in-hospital cardiac arrest. Setting: Tertiary medical center. Patients: In-hospital cardiac arrest patients (n = 34). Main Results: Cerebral oximetry provided real-time information regarding the quality of perfusion and oxygen delivery. The use of automated mechanical chest compression device (n = 1 2) was associated with higher regional cerebral oxygen saturation com- pared with manual chest compression device (n = 22) (53.1% ± 23.4% vs 24% ± 25%, p = 0.002). There was a significant difference in mean regional cerebral oxygen saturation (median % ± interquartile range) in patients who achieved return of spontaneous circulation (n = 15) compared with those without return of spontaneous circulation (n = 19) (47.4% ± 21.4%; vs 23% ± 1 8.42%, p <0.001). After controlling for patients achieving return of spontaneous circulation or not, significantly higher mean regional cerebral oxygen saturation levels during cardiopulmonary resuscitation were observed in patients who were resuscitated using automated mechanical chest compression device (p < 0.001). Conclusions: The integration of cerebral oximetry into cardiac arrest resuscitation provides a novel noninvasive method to determine the quality of cerebral perfusion and oxygen delivery to the brain. The use of automated mechanical chest compression device during in-hospital cardiac arrest may lead to improved oxygen delivery and organ perfusion. [ABSTRACT FROM AUTHOR]

Abstract: To date there has been no reliable noninvasive real time monitoring available to determine cerebral perfusion during cardiac arrest. Objectives: To investigate the feasibility of using a commercially available cerebral oximeter during in-hospital cardiac arrest, and determine whether this parameter predicts return of spontaneous circulation (ROSC). Methods: Cerebral oximetry was incorporated in cardiac arrest management in 19 in-hospital cardiac arrest cases, five of whom had ROSC. The primary outcome measure was the relationship between rSO2 and ROSC. Results: The use of cerebral oximetry was found to be feasible during in hospital cardiac arrest and did not interfere with management. Patients with ROSC had a significantly higher overall mean±SE rSO2 (35±5 vs. 18±0.4, p <0.001). The difference in mean rSO2 between survivors and non-survivors was most pronounced in the final 5min of cardiac arrest (48±1 vs. 15±0.2, p <0.0001) and appeared to herald imminent ROSC. Although spending a significantly higher portion of time with an rSO2 >40% was found in survivors (p <0.0001), patients with ROSC had an rSO2 above 30% for >50% of the duration of cardiac arrest, whereas non-survivors had an rSO2 that was below 30%>50% of their cardiac arrest. Patients with ROSC also had a significantly higher change in rSO2 from baseline compared to non-survivors (310%±60% vs. 150%±27%, p <0.05). Conclusion: Cerebral oximetry may have a role in predicting ROSC and the optimization of cerebral perfusion during cardiac arrest. [Copyright &y& Elsevier]

Objective: Cerebral oximetry is a non-invasive system that uses near infrared spectroscopy to measure regional cerebral oxygenation (rSO2) in the frontal lobe of the brain. Post-cardiac arrest rSO2 may be associated with survival and neurological outcomes in out-of-hospital cardiac arrest patients; however, no studies have examined relationships between rSO2 and neurological outcomes following in-hospital cardiac arrest (IHCA). We tested the hypothesis that rSO2 following IHCA is associated with survival and favorable neurological outcomes.Design: Prospective study from nine acute care hospital in the United States and United Kingdom.Patients: Convenience sample of IHCA patients admitted to the intensive care unit with post-cardiac arrest syndrome.Interventions: Cerebral oximetry monitoring (Equanox 7600, Nonin Medical, MN, USA) during the first 48 h after IHCA.Measurements and Main Results: Subject's rSO2 was calculated as the mean of collected data at different time intervals: hourly between 1-6 h, 6-12 h, 12-18 h, 18-24 h and 24-48 h. Demographic data pertaining to possible confounding variables for rSO2 and primary outcome were collected. The primary outcome was survival with favorable neurological outcomes (cerebral performance scale [CPC] 1-2) vs severe neurological injury or death (CPC 3-5) at hospital discharge. Univariate and multivariate statistical analyses were performed to correlate cerebral oximetry values and other variables with the primary outcome. Among 87 studied patients, 26 (29.9%) achieved CPC 1-2. A significant difference in mean rSO2 was observed during hours 1-2 after IHCA in CPC 1-2 vs CPC 3-5 (73.08 vs. 66.59, p = 0.031) but not at other time intervals. There were no differences in age, Charlson comorbidity index, APACHE II scores, CPR duration, mean arterial pressure, PaO2, PaCO2, and hemoglobin levels between two groups.Conclusions: There may be a significant physiological difference in rSO2 in the first two hours after ROSC in IHCA patients who achieve favorable neurological outcomes, however, this difference may not be clinically significant. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Background: One of the major causes of death and neurological injury after cardiac arrest is delayed ischemia combined with oxygen free radical mediated reperfusion injury. Consequently determining the optimal balance between oxygen delivery and uptake in the brain using a reliable non-invasive monitoring system during the post-resuscitation period is of importance. In this observational study, we evaluated the feasibility of using cerebral oximetry during the post-resuscitation period in order to identify changes in regional cerebral oxygen saturation (rSO2) and its association with survival to discharge. Methods: 21 consecutive patients admitted to the intensive care units following cardiac arrest had cerebral oximetry monitoring carried out for 48h. Mean rSO2 values were collected during the first 24h and then again during the subsequent 24–48h of the post-resuscitation period. Results: 43% (n =9) patients survived to hospital discharge and 57% (n =12) died. Amongst all patients the median (IQR) rSO2% was 65.5% (62.6–68.2) in the first 24-h following ROSC and increased to 72.1% (64.6–73.7) (p =0.11) in the subsequent 24–48h. The median (IQR) rSO2% during the first 24h in patients who survived to discharge compared to those who did not survive were significantly higher 68.2% (66.0–71.0) vs. 62.9% (56.5–66.0), p =0.01). During the subsequent 24–48h period, while a difference in the rSO2 between survivors and non-survivors was noted, this did not achieve statistical significance (median (IQR): 73.7 (70.2–74.0) vs. 66.5 (58.2–72.1), p =0.11). Conclusions: Our study indicates that the use of cerebral oximetry is feasible during the post resuscitation period after cardiac arrest. Further studies are needed to determine whether cerebral oximetry may be used as a novel non-invasive monitoring system to evaluate changes in the balance between cerebral oxygen delivery and uptake during the post-resuscitation period. [Copyright &y& Elsevier]

Abstract: Background: Non-invasive monitoring of cerebral perfusion and oxygen delivery during cardiac arrest is not routinely utilized during cardiac arrest resuscitation. The objective of this study was to investigate the feasibility of using cerebral oximetry during cardiac arrest and to determine the relationship between regional cerebral oxygen saturation (rSO2) with return of spontaneous circulation (ROSC) in shockable (VF/VT) and non-shockable (PEA/asystole) types of cardiac arrest. Methods: Cerebral oximetry was applied to 50 in-hospital and out-of-hospital cardiac arrest patients. Results: Overall, 52% (n =26) achieved ROSC and 48% (n =24) did not achieve ROSC. There was a significant difference in mean±SD rSO2% in patients who achieved ROSC compared to those who did not (47.2±10.7% vs. 31.7±12.8%, p <0.0001). This difference was observed during asystole (median rSO2 (IQR) ROSC versus no ROSC: 45.0% (35.1–48.8) vs. 24.9% (20.5–32.9), p <0.002) and PEA (50.6% (46.7–57.5) vs. 31.6% (18.8–43.3), p =0.02), but not in the VF/VT subgroup (43.7% (41.1–54.7) vs. 42.8% (34.9–45.0), p =0.63). Furthermore, it was noted that no subjects with a mean rSO2<30% achieved ROSC. Conclusions: Cerebral oximetry may have a role as a real-time, non-invasive predictor of ROSC during cardiac arrest. The main utility of rSO2 in determining ROSC appears to apply to asystole and PEA subgroups of cardiac arrest, rather than VF/VT. This observation may reflect the different physiological factors involved in recovery from PEA/asytole compared to VF/VT. Whereas in VF/VT, successful defibrillation is of prime importance, however in PEA and asytole achieving ROSC is more likely to be related to the quality of oxygen delivery. Furthermore, a persistently low rSO2 <30% in spite of optimal resuscitation methods may indicate futility of resuscitation efforts. [Copyright &y& Elsevier]