A feasibility study evaluating the role of cerebral oximetry in predicting return of spontaneous circulation in cardiac arrest

Wolf Creek XVII Part 6: Physiology-Guided CPR

Introduction

Physiology-guided cardiopulmonary resuscitation (CPR) offers the potential to optimize resuscitation and enable early prognosis.

Methods

Physiology-Guided CPR was one of six focus topic for the Wolf Creek XVII Conference held on June 14-17, 2023 in Ann Arbor, Michigan, USA. International thought leaders and scientists in the field of cardiac arrest resuscitation from academia and industry were invited. Participants submitted via online survey knowledge gaps, barriers to translation and research priorities for each focus topic. Expert panels used the survey results and their own perspectives and insights to create and present a preliminary unranked list for each category, which was then debated, revised and ranked by all attendees to identify the top 5 for each category.

Results

Top knowledge gaps include identifying optimal strategies for the evaluation of physiology-guided CPR and the optimal values for existing patients using patient outcomes. The main barriers to translation are the limited usability outside of critical care environments and the training and equipment required for monitoring. The top research priorities are the development of clinically feasible and reliable methods to continuously and non-invasively monitor physiology during CPR and prospective human studies proving targeting parameters during CPR improves outcomes.

Conclusion

Physiology-guided CPR has the potential to provide individualized resuscitation and move away from a one-size-fits-all approach. Current understanding is limited, and clinical trials are lacking. Future developments need to consider the clinical application and applicability of measurement to all healthcare settings. Therefore, clinical trials using physiology-guided CPR for individualisation of resuscitation efforts are needed.

Skeletal muscle oxygenation during cardiopulmonary resuscitation as a predictor of return of spontaneous circulation: a pilot study

BACKGROUND

Near-infrared spectroscopy (NIRS) provides regional tissue oxygenation (rSO2) even in pulseless states, such as out-of-hospital cardiac arrest (OHCA). Brain rSO2 seems to be important predictor of return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). Aim of our study was to explore feasibility for monitoring and detecting changes of skeletal muscle rSO2 during resuscitation.

METHODS

Skeletal muscle and brain rSO2 were measured by NIRS (SenSmart Model X-100, Nonin, USA) during CPR in adult patient with OHCA. Start (basal) rSO2, maximal during CPR (maximal) and difference between maximal-minimal rSO2 (delta-rSO2), were recorded. Patients were divided into ROSC and NO-ROSC group.

RESULTS

20 patients [age: 66.0ys (60.5-79.5), 65% male] with OHCA [50% witnessed, 70% BLS, time to ALS 13.5 min (11.0-19.0)] were finally analyzed. ROSC was confirmed in 5 (25%) patients. Basal and maximal skeletal muscle rSO2 were higher in ROSC compared to NO-ROSC group [49.0% (39.7-53.7) vs. 15.0% (12.0-25.2), P =  0.006; 76.0% (52.7-80.5) vs. 34.0% (18.0-49.5), P =  0.005, respectively]. There was non-linear cubic relationship between time of collapse and basal skeletal muscle rSO2 in witnessed OHCA and without BLS (F-ratio = 9.7713, P =  0.0261). There was correlation between maximal skeletal muscle and brain rSO2 (n = 18, rho: 0.578, P =   0.0121).

CONCLUSIONS

Recording of skeletal muscle rSO2 during CPR in patients with OHCA is feasible. Basal and maximal skeletal muscle rSO2 were higher in ROSC compared to NO-ROSC group. Clinical trial registration number ClinicalTrials.gov, NCT04058925, registered on: 16th August 2019. URL of trial registry record: https://www.

CLINICALTRIALS

gov/ct2/show/NCT04058925?titles=Tissue+Oxygenation+During+Cardiopulmonary+Resuscitation+as+a+Predictor+of+Return+of+Spontaneous+Circulation&draw=2&rank=1 .

Differences in Cerebral Oxygenation in Cardiogenic and Respiratory Cardiac Arrest Before, During, and After Cardiopulmonary Resuscitation

We compared the changes in cerebral oxygen saturation (ScO₂) levels during cardiac arrest (CA) events using porcine models of ventricular fibrillation CA (VF-CA) and asphyxial CA (A-CA). Twenty female pigs were randomly divided into VF-CA and A-CA groups. We initiated cardiopulmonary resuscitation (CPR) 4 min after CA and measured the cerebral tissue oxygenation index (TOI) using near-infrared spectroscopy (NIRS) before, during, and after CPR. In both groups, the TOI was the lowest at 3-4 min after pre-CPR phase initiation (VF-CA group: 3.4 min [2.8-3.9]; A-CA group: 3.2 min [2.9-4.6]; p = 0.386). The increase in TOI differed between the groups in the CPR phase (p < 0.001); it increased more rapidly in the VF-CA group (16.6 [5.5-32.6] vs. 1.1 [0.6-3.3] %/min; p < 0.001). Seven pigs surviving for 60 min after the return of spontaneous circulation in the VF-CA group recovered limb movement, whereas only one in the A-CA group (p = 0.023) achieved movement recovery. The increase in the TOI did not differ significantly between the groups in the post-CPR phase (p = 0.341). Therefore, it is better to monitor ScO₂ concomitantly with CPR initiation using NIRS to assess the responsiveness to CPR in clinical settings.

A Pilot Study to Examine the Effect of Passive Straight Leg Raise Performed During Cardiopulmonary Resuscitation on Cerebral Perfusion Measured by Noninvasive Cerebral Oximetry

Passive leg raise (PLR) during cardiopulmonary resuscitation (CPR) is simple and noninvasive maneuver, which can potentially improve patient-related outcomes. Initial CPR guidelines have previously advocated "elevation of the lower extremities to augment artificial circulation during CPR." There is lack of supporting evidence for this recommendation.

DESIGN

This was a double cross-over physiologic efficacy randomized study.

SETTING AND PATIENTS

Study in 10 subjects with in-hospital cardiac arrest for whom CPR was undertaken.

INTERVENTION

Subjects were randomized to receive two cycles of CPR with PLR followed by two cycles of CPR without PLR (Group I) or vice-versa (Group II). Subjects had their foreheads (right and left) fitted with near infrared spectroscopy (NIRS) electrodes (O3 System-Masimo, Masimo corporation Forty Parker, Irvine CA) while undergoing CPR during the study. NIRS readings, a measure of mixed venous, arterial, and capillary blood oxygen saturation, act as a surrogate measure of cerebral blood perfusion during CPR.

MEASUREMENT AND MAIN RESULTS

PLR was randomly used "first" in five of them, whereas it was used "second" in the remaining five subjects. In subjects in whom PLR was performed during first two cycles (Group I), NIRS values were initially significantly greater. The performance of PLR during CPR in Group II attenuated the decline in NIRS readings during CPR.

CONCLUSIONS

PLR during CPR is feasible and leads to augmentation of cerebral blood flow. Furthermore, the expected decline in cerebral blood flow over time during CPR may be attenuated by this maneuver. The clinical significance of these findings will require further investigations.

Prehospital monitoring of cerebral circulation during out of hospital cardiac arrest ? A feasibility study

BACKGROUND

About two-thirds of the in-hospital deaths after out-of-hospital cardiac arrests (OHCA) are a consequence of anoxic brain injuries, which are due to hypoperfusion of the brain during the cardiac arrests. Being able to monitor cerebral perfusion during cardiopulmonary resuscitation (CPR) is desirable to evaluate the effectiveness of the CPR and to guide further decision making and prognostication.

METHODS

Two different devices were used to measure regional cerebral oxygen saturation (rSO2): INVOS™ 5100 (Medtronic, Minneapolis, MN, USA) and Root® O3 (Masimo Corporation, Irvine, CA, USA). At the scene of the OHCA, advanced life support (ALS) was immediately initiated by the Emergency Medical Services (EMS) personnel. Sensors for measuring rSO2 were applied at the scene or during transportation to the hospital. rSO2 values were documented manually together with ETCO2 (end tidal carbon dioxide) on a worksheet specially designed for this study. The study worksheet also included a questionnaire for the EMS personnel with one statement on usability regarding potential interference with ALS.

RESULTS

Twenty-seven patients were included in the statistical analyses. In the INVOS™5100 group (n = 13), the mean rSO2 was 54% (95% CI 40.3-67.7) for patients achieving a return of spontaneous circulation (ROSC) and 28% (95% CI 12.3-43.7) for patients not achieving ROSC (p = 0.04). In the Root® O3 group (n = 14), the mean rSO2 was 50% (95% CI 46.5-53.5) and 41% (95% CI 36.3-45.7) (p = 0.02) for ROSC and no ROSC, respectively. ETCO2 values were not statistically different between the groups. The EMS personnel graded the statement of interference with ALS to a median of 2 (IQR 1-6) on a 10-point Numerical Rating Scale.

CONCLUSION

Our results suggest that both INVOS™5100 and ROOT® O3 can distinguish between ROSC and no ROSC in OHCA, and both could be used in the pre-hospital setting and during transport with minimal interference with ALS.

Novel Mode of Near-Infrared Spectroscopy as a Continuous Cerebral Physiological Monitoring Device during Cardiopulmonary Resuscitation: Four Case Reports

Background: NIRO-Pulse is a novel mode of near-infrared spectroscopy that can be used to visually evaluate cerebral perfusion during cardiopulmonary resuscitation (CPR), providing real-time feedback as to the quality of the CPR. The aim of this report was to describe the several representative cases of NIRO-Pulse for physiological monitoring during CPR. Methods: We present several cases from out-of-hospital cardiac arrest (OHCA) patients for whom NIRO-Pulse was attached to the forehead after hospital arrival. Patients were subjected to continuous brain monitoring during CPR using NIRO-Pulse, which allows for the visualisation of ΔHb (Hb pulsation). NIRO-Pulse is capable of simultaneously measuring and displaying cerebral tissue oxygen saturation (SctO2) and Hb pulsation, providing real-time feedback during CPR in the form of physiological indicators, and assessing changes in SctO2 throughout the CPR procedure by post-mortem analysis. Results: We observed several representative cases that provided the following insights: (1) SctO2 increased after a change in the quality of chest compression, (2) SctO2 decreased during the ventilation phase of synchronised CPR, (3) SctO2 decreased during the interruption of chest compressions for the preparation of defibrillation, and (4) SctO2 gradually and continuously increased after return of spontaneous circulation. Conclusion: Displaying Hb pulsation in conjunction with SctO2 during CPR may be helpful for evaluating the quality of and patient responsiveness to CPR. Further studies investigating the association between the use of NIRO-Pulse during CPR and subsequent outcomes should be conducted.

Near-infrared spectroscopy during cardiopulmonary resuscitation for pediatric cardiac arrest: a prospective, observational study

AIM

Cerebral oxygenation (rSO2) is not routinely measured during pediatric cardiopulmonary resuscitation (CPR). We aimed to determine whether higher intra-arrest rSO2 was associated with return of spontaneous circulation (ROSC) and survival to hospital discharge.

METHODS

Prospective, single-center observational study of cerebral oximetry using near-infrared spectroscopy (NIRS) during pediatric cardiac arrest from 2016 to 2020. Eligible patients had ≥30 s of rSO2 data recorded during CPR. We compared median rSO2 and percentage of rSO2 measurements above a priori thresholds for the entire event and the final five minutes of the CPR event between patients with and without ROSC and survival to discharge.

RESULTS

Twenty-one patients with 23 CPR events were analyzed. ROSC was achieved in 17/23 (73.9%) events and five/21 (23.8%) patients survived to discharge. The median rSO2 was higher for events with ROSC vs. no ROSC for the overall event (62% [56%, 70%] vs. 45% [35%, 51%], p = 0.025) and for the final 5 minutes of the event (66% [55%, 72%] vs. 43% [35%, 44%], p = 0.01). Patients with ROSC had a higher percentage of measurements above 50% during the final five minutes of CPR (100% [100%, 100%] vs. 0% [0%, 29%], p = 0.01). There was no association between rSO2 and survival to discharge.

CONCLUSIONS

Higher cerebral rSO2 during CPR for pediatric cardiac arrest was associated with higher rates of ROSC but not with survival to discharge.

Real-Time Brain Monitoring by Near-Infrared Spectroscopy Predicts Neurological Outcome after Cardiac Arrest and Resuscitation in Rats: A Proof of Concept Study of a Novel Prognostic Measure after Cardiac Arrest

Clinical studies have demonstrated that dynamic changes in regional cerebral oxygen saturation (rSO₂) after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) have a role in predicting neurological outcomes after the return of spontaneous circulation (ROSC). Our study evaluated whether the timing of rSO₂ decline shortly after CPR reflects the severity of brain injury in a rat model of CA. Rats were subjected to different durations of asphyxia to produce variable severities of brain injury, due to CA. Time from ROSC to achieving the initial minimum rSO₂ was defined as T_nadir. A T_nadir cut-off of 24 min had optimal sensitivity and specificity for predicting good neurological outcomes at 72 h after ROSC (AUC, 0.88; sensitivity, 89%; specificity, 86%; p < 0.01). Immunohistochemistry at 72 h post-CA revealed that the number of Fluoro-Jade B positive degenerating neurons in the hippocampus CA1 sector were markedly higher in animals with T_nadir > 24 min than that in animals with T_nadir ≤ 24 min. There was no difference in the gene expressions of cytokines and mitochondrial fission proteins in the brain at 2 h after ROSC between rats with T_nadir > 24 min and with T_nadir ≤ 24 min. In conclusion, T_nadir can be a novel predictor of good neurological outcomes after CA/CPR.

Cerebral oximetry: a developing tool for monitoring cerebral oxygenation during cardiopulmonary resuscitation

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.

Mildly Reduced Doses of Adrenaline Do Not Affect Key Hemodynamic Parameters during Cardio-Pulmonary Resuscitation in a Pig Model of Cardiac Arrest

Adrenaline is recommended for cardiac arrest resuscitation, but its effectiveness has been questioned recently. Achieving return of spontaneous circulation (ROSC) is essential and is obtained by increasing coronary perfusion pressure (CPP) after adrenaline injection. A threshold as high as 35 mmHg of CPP may be necessary to obtain ROSC, but increasing doses of adrenaline might be harmful to the brain. Our study aimed to compare the increase in CPP with reduced doses of adrenaline to the recommended 1 mg dose in a pig model of cardiac arrest. Fifteen domestic pigs were randomized into three groups according to the adrenaline doses: 1 mg, 0.5 mg, or 0.25 mg administered every 5 min. Cardiac arrest was induced by ventricular fibrillation; after 5 min of no-flow, mechanical chest compression was resumed. The Wilcoxon test and Kruskal-Wallis exact test were used for the comparison of groups. Fisher's exact test was used to compare categorical variables. CPP, EtCO2 level, cerebral, and tissue near-infrared spectroscopy (NIRS) were measured. CPP was significantly lower in the 0.25 mg group 90 s after the first adrenaline injection: 28.9 (21.2; 35.4) vs. 53.8 (37.8; 58.2) in the 1 mg group (p = 0.008), while there was no significant difference with 0.5 mg 39.6 (32.7; 52.5) (p = 0.056). Overall, 0.25 mg did not achieve the threshold of 35 mmHg. EtCO2 levels were higher at T12 and T14 in the 0.5 mg than in the standard group: 32 (23; 35) vs. 19 (16; 26) and 26 (20; 34) vs. 19 (12; 22) (p < 0.05). Cerebral and tissue NIRS did not show a significant difference between the three groups. CPP after 0.5 mg boluses of adrenaline was not significantly different from the recommended 1 mg in our model of cardiac arrest.

The role of non-invasive brain oximetry in adult critically ill patients without primary brain injury

A primary objective in intensive care and perioperative settings is to promote an adequate supply and delivery of oxygen to tissues and organs, particularly to the brain. Cerebral near infrared spectroscopy (NIRS) is a non-invasive, continuous monitoring technique, that can be used to assess cerebral oxygenation. Using NIRS to monitor cerebral oximetry is not new, and has been in widespread use in neonates and cardiac surgery for decades. In addition, it has become common to see NIRS being used in adult and pediatric cardiac surgery, acute neurological diseases, neurosurgical procedures, vascular surgery, severe trauma and other acute medical diseases. Furthermore, recent evidence suggests a role for NIRS in the perioperative settings; detecting and preventing episodes of cerebral desaturation aiming to reduce the development of post-operative delirium. NIRS is not without its limitations; these include the risk of extra-cranial contamination, spatial limitations and skin blood flow/volume changes, as well being a measure of localized blood oxygenation underneath the sensor. However, NIRS is a non-invasive technique and can, therefore, be used in those patients without indications or justification for invasive brain monitoring; non-neurosurgical procedures such as liver transplantation, major orthopedic surgery and critically illness where the brain is at risk. The aim of this manuscript was to discuss the physical principles of NIRS and to report the current evidence regarding its use in critically ill patients without primary non-anoxic brain injury.

Cerebral regional oxygen saturation during cardiopulmonary resuscitation and return of spontaneous circulation: A systematic review and meta-analysis

AIM

Predicting the return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation in victims of cardiac arrest (CA) remains challenging. Cerebral regional oxygen saturation (rSO2) measured during resuscitation is feasible, and higher initial and overall values seem associated with ROSC. However, these observations were limited to the analysis of few small single-centre studies. There is a growing number of studies evaluating the role of cerebral rSO2 in the prediction of ROSC.

METHODS

We conducted an updated meta-analysis aimed at investigating the association of initial and overall values of cerebral rSO2 with ROSC after CA. We performed subgroups analyses according to the location of CA and conducted a secondary analysis according to the country where the study was conducted (resuscitation practice varies greatly for out-of-hospital CA).

RESULTS

We included 17 studies. Higher initial rSO2 values (11 studies, n = 2870, 16.6% achieved ROSC) were associated with ROSC: Mean Difference (MD) -11.54 [95%Confidence Interval (CI)-20.96, -2.12]; p = 0.02 (I² = 97%). The secondary analysis confirmed this finding when pooling together European and USA studies, but did not for Japanese studies (p = 0.06). One multi-centre Japanese study was an outlier with large influence on 95%CI. Higher overall rSO2 values during resuscitation (9 studies, n = 894, 33.7% achieving ROSC) were associated with ROSC: MD-10.38; [-13.73, -7.03]; p < 0.00001 (I² = 77%). All studies were conducted in Europe/USA.

CONCLUSIONS

This updated meta-analysis confirmed the association between higher initial and overall values of cerebral rSO2 and ROSC after CA. However, we found geographical differences, since this association was not present when Japanese studies were analysed separately.

Near-Infrared Spectroscopy Assessments of Regional Cerebral Oxygen Saturation for the Prediction of Clinical Outcomes in Patients With Cardiac Arrest: A Review of Clinical Impact, Evolution, and Future Directions

Despite three decades of advancements in cardiopulmonary resuscitation (CPR) methods and post-resuscitation care, neurological prognosis remains poor among survivors of out-of-hospital cardiac arrest, and there are no reliable methods for predicting neurological outcomes in patients with cardiac arrest (CA). Adopting more effective methods of neurological monitoring may aid in improving neurological outcomes and optimizing therapeutic interventions for each patient. In the present review, we summarize the development, evolution, and potential application of near-infrared spectroscopy (NIRS) in adults with CA, highlighting the clinical relevance of NIRS brain monitoring as a predictive tool in both pre-hospital and in-hospital settings. Several clinical studies have reported an association between various NIRS oximetry measurements and CA outcomes, suggesting that NIRS monitoring can be integrated into standardized CPR protocols, which may improve outcomes among patients with CA. However, no studies have established acceptable regional cerebral oxygen saturation cut-off values for differentiating patient groups based on return of spontaneous circulation status and neurological outcomes. Furthermore, the point at which resuscitation efforts can be considered futile remains to be determined. Further large-scale randomized controlled trials are required to evaluate the impact of NIRS monitoring on survival and neurological recovery following CA.

Comparison of manual and mechanical chest compression techniques using cerebral oximetry in witnessed cardiac arrests at the emergency department: A prospective, randomized clinical study

AIM

We aimed to compare regional cerebral oxygen saturation (rSO₂) levels during cardiopulmonary resuscitation (CPR), performed either manually or using a mechanical chest compression device (MCCD), in witnessed cardiac arrest cases in the emergency department (ED), and to evaluate the effects of both the CPR methods and perfusion levels on patient survival and neurological outcomes.

METHODS

This single-center, randomized study recruited patients aged ≥18 years who had witnessed a cardiopulmonary arrest in the ED. According to the relevant guidelines, CPR was performed either manually or using an MCCD. Simultaneously, rSO₂ levels were continually measured with near-infrared spectroscopy.

RESULTS

Seventy-five cases were randomly distributed between the MCCD (n = 40) and manual CPR (n = 35) groups. No significant difference in mean rSO₂ levels was found between the MCCD and manual CPR groups (46.35 ± 14.04 and 46.60 ± 12.09, respectively; p = 0.541). However, a significant difference in rSO₂ levels was found between patients without return of spontaneous circulation (ROSC) and those with ROSC (40.35 ± 10.05 and 50.50 ± 13.44, respectively; p < 0.001). In predicting ROSC, rSO₂ levels ≥24% provided 100% sensitivity (95% confidence interval [CI] 92-100), and rSO₂ levels ≥64% provided 100% specificity (95% CI 88-100). The area under the curve for ROSC prediction using rSO₂ levels during CPR was 0.74 (95% CI 0.62-0.83).

CONCLUSION

A relationship between ROSC and high rSO₂ levels in witnessed cardiac arrests exists. Monitoring rSO₂ levels during CPR would be useful in CPR management and ROSC prediction. During CPR, MCCD or manual chest compression has no distinct effect on oxygen delivery to the brain.

TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT03238287.

Association between cerebral oximetry and return of spontaneous circulation following cardiac arrest: A systematic review and meta-analysis

The present meta-analysis was based on the available studies to determine the potential role of the initial and regional cerebral oxygen saturation (rSO2) in monitoring the efficiency of cardiopulmonary resuscitation (CPR) and predicting the return of spontaneous circulation (ROSC). Three electronic databases of PubMed, Embase, and the Cochrane Library were searched to identify the studies that investigated the role of rSO2 on ROSC in CA patients throughout May 2018. The weighted mean difference (WMD) with 95% confidence interval (CI) was calculated to estimate the pooled effect using a random-effects model. Sensitivity, subgroup analyses, and publication bias were conducted. A total of 13 studies involving 678 CA patients (300 in-hospital (IH) patients, and 378 out-hospital (OH) patients) were included. The summary WMD suggested that ROSC patients were associated with higher initial rSO2 (WMD: 10.10%; 95% CI: 5.66–14.55; P<0.001) and mean rSO2 (WMD: 14.16%; 95% CI: 10.51–17.81; P<0.001) levels during CA and ROSC as compared to the non-ROSC. The results of meta-regression suggested that the male percentage and the location of cardiac arrest might bias the initial or mean rSO2 and the incidence of ROSC. These significant differences were observed in nearly all subsets. The findings of this study suggested that high initial or mean rSO2 levels were both associated with an increased incidence of ROSC in CA patients undergoing CPR. These correlations might be affected by the percentage of males or the location of cardiac arrest, thereby necessitating further large-scale studies to substantiate whether these correlations differ according to gender and the location of cardiac arrest.

Cerebral oxygenation monitoring during resuscitation by emergency medical technicians: a prospective multicenter observational study

Aim

To assess the feasibility and predictive ability of regional cerebral oxygen saturation monitoring during cardiopulmonary resuscitation by emergency medical technicians.

Methods

This prospective observational study included 33 cardiac arrest patients who received cardiopulmonary resuscitation in a prehospital setting. Patients were connected to a near‐infrared spectrometer through two disposable probes immediately after entering the ambulance. The monitor, which showed regional cerebral oxygen saturation readings, was obscured by covering it with a sheet of paper. Regional cerebral oxygen saturation was measured continuously until hospital arrival. Outcome variables included the prehospital return of spontaneous circulation, survival to hospital admission, and survival at 90 days.

Results

For patients who survived >90 days after hospital admission (n = 2), the mean regional cerebral oxygen saturation values upon ambulance and hospital arrival were 24% and 60%, respectively; for patients who did not survive (n = 31), the mean regional cerebral oxygen saturation values were 15% and 17%, respectively. Regional cerebral oxygen saturation values increased to a greater extent between ambulance arrival and hospital arrival in patients who survived >90 days (median, 36%; interquartile range, 32–40%) than in those who did not survive (0; 0–6%; P = 0.07). Additionally, regional cerebral oxygen saturation values were not related to the prehospital return of spontaneous circulation or survival to hospital admission.

Conclusion

Regional cerebral oxygen saturation could be monitored during resuscitation by emergency medical technicians, and it can be used during physiological monitor‐guided cardiopulmonary resuscitation.

Prediction of the neurological outcome using regional cerebral oxygen saturation in patients with extracorporeal cardiopulmonary resuscitation after out-of-hospital cardiac arrest: a multicenter retrospective cohort study

Aim

To investigate the association between regional cerebral oxygen saturation (rSO2) and neurological outcomes in extracorporeal cardiopulmonary resuscitation (ECPR) patients after out‐of‐hospital cardiac arrest (OHCA).

Methods

We used data from the Japan‐Prediction of Neurological Outcomes in Patients Post‐Cardiac Arrest Registry. This registry included consecutive comatose patients after OHCA who were transferred to 15 hospitals in Japan from 2011 to 2013. Our primary end‐point was a good neurological outcome (cerebral performance categories 1 or 2) at 90 days after OHCA.

Results

Among the enrolled patients, 121 (6.3%) received ECPR. Eleven (9.1%) had a good neurological outcome. Receiver operating characteristic curve analysis revealed the optimal cut‐off value as >16%. Good neurological outcomes were observed in 19.6% (9/46) and 2.7% (2/74) of patients with rSO2 >16% and rSO2 ≤16%, respectively.

Conclusion

The neurological outcome of ECPR patients differed according to their rSO2 values. When considering ECPR, the rSO2 value could be important in addition to other criteria. Further studies that focus on ECPR patients and serial rSO2 values are needed.

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.

Use of Near-Infrared Spectroscopy by Paramedics During Out-of-Hospital Cardiac Arrest: A Feasibility Study

Near-infrared spectroscopy (NIRS) provides continuous real-time measurement of regional cerebral oxygen saturation (rSO₂) during resuscitation. We aimed to evaluate the feasibility of paramedics using NIRS during out-of-hospital cardiac arrest (OHCA) resuscitation. Paramedics were trained to record rSO₂ and mark events during resuscitation. Feasibility was defined as > 70% of cases with rSO₂ data and event markers. The monitor was applied on 23 patients with OHCA. Of these, 19 (83%) had rSO₂ data (median duration of 17.9 minutes; interquartile range, 9.7-28) and 17 (74%) had event markers (median 3 events per case; interquartile range, 1-4). It is feasible for paramedics to apply NIRS during OHCA resuscitation.

Physiology-directed cardiopulmonary resuscitation: advances in precision monitoring during cardiac arrest

PURPOSE OF REVIEW

We review the recent advances in physiologic monitoring during cardiac arrest and offer an evidence-based framework for prioritizing physiologic targets during cardiopulmonary resuscitation (CPR).

RECENT FINDINGS

Current CPR guidelines recommend a uniform approach for all patients in cardiac arrest, but newer data support a precision strategy that uses the individual patient's physiology to guide resuscitation. Coronary perfusion pressure and arterial DBP are associated with survival outcomes in recent animal and human studies. End-tidal carbon dioxide is a reasonable noninvasive alternative, but may be inferior to invasive hemodynamic endpoints. Cerebral oximetry and cardiac ultrasound are emerging physiologic indicators of CPR effectiveness.

SUMMARY

Physiologic monitoring can and should be used to deliver precision CPR whenever possible and may improve outcomes after cardiac arrest.

A Case of Persistence of Normal Tissue Oxygenation Monitored by Near-Infrared Spectroscopy (NIRS) Values Despite Prolonged Perioperative Cardiac Arrest

Patient: Male, 65

Final Diagnosis: Aortic dissection

Symptoms: Hemiplegia • hypotension

Medication:—

Clinical Procedure: Emergent surgery

Specialty: Surgery

Evolving Strategies in Cardiac Arrest Management

Cardiac arrest is a leading cause of death in the United States, with a hospital discharge rate of approximately 10%. International resuscitation guidelines offer standardized cardiac arrest management approaches, but beyond the guidelines, are promising innovations to improve resuscitative care. Although clinical data do not yet support the routine use of mechanical chest compressions, corticosteroids, thrombolytics, and adjunctive ventilation devices during arrest, these therapies may have an important role in select patients. Extracorporeal membrane oxygenation during cardiopulmonary resuscitation is a promising advancement and may have survival benefit in select patients. The evidence for standard therapies and these innovations is discussed.

Cerebral saturation in cardiac arrest patients measured with near-infrared technology during pre-hospital advanced life support. Results from Copernicus I cohort study

AIM

To date, monitoring options during pre-hospital advanced life support (ALS) are limited. Regional cerebral saturation (rSO₂) may provide more information concerning the brain during ALS. We hypothesized that an increase in rSO₂ during ALS in out-of hospital cardiac arrest (OHCA) patients is associated with return of spontaneous circulation (ROSC).

METHODS

A prospective, non-randomized multicenter study was conducted in the pre-hospital setting of six hospitals in Belgium. Cerebral saturation was measured during pre-hospital ALS by a medical emergency team in OHCA patients. Cerebral saturation was continuously measured until ALS efforts were terminated or until the patient with sustained ROSC (>20 min) arrived at the emergency department. To take the longitudinal nature of the data into account, a linear mixed model was used. The correlation between the repeated measures of a patient was handled by means of ​a random intercept and a random slope. Our primary analysis tested the association of rSO₂ with ROSC.

RESULTS

Of the 329 patients 110 (33%) achieved ROSC. First measured rSO₂ was 30% ± 18 in the ROSC group and 24% ± 15 in the no-ROSC group (p = .004; mean ± SD). Higher mean rSO₂ values were observed in the ROSC group compared to the no-ROSC group (41% ± 13 versus 33% ± 13 respectively; p < 0.001). The median increase in rSO_2, measured from start until two minutes before ROSC, was higher in the ROSC group (ROSC group 17% (IQR 6-29)) than in the no-ROSC group (8% (IQR 2-13); p < 0.001). An increase in rSO₂ above 15% was associated with ROSC (OR 4.5; 95%CI 2.747-7.415; p < 0.001).

CONCLUSION

Regional cerebral saturation measurements can be used during pre-hospital ALS as an additional marker to predict ROSC. An increase of at least 15% in rSO₂ during ALS is associated with a higher probability of ROSC.

Regional cerebral oxygen saturation during cardiopulmonary resuscitation as a predictor of return of spontaneous circulation and favourable neurological outcome - A review of the current literature

INTRODUCTION

Regional cerebral oxygen saturation (rSO2) can be measured non-invasively even at no- or low-flow states. It thus allows assessment of brain oxygenation during CPR. Certain rSO2 values had been associated with return of spontaneous circulation (ROSC) and neurological outcome in the past. Clear-cut thresholds for the prediction of beneficial outcome, however, are still lacking.

METHODS

We conducted a database search to extract all available investigations on rSO2 measurement during CPR. Mean, median, and ΔrSO2 values were either taken from the studies or calculated. Thresholds for the outcome "ROSC" and "neurological outcome" were sought.

RESULTS

We retrieved 26 publications for the final review. The averaged mean rSO2 for patients achieving ROSC was 41 ± 12% vs. 30 ± 12% for non-ROSC (p = .009). ROSC was not observed when mean rSO2 remained <26%. In ROSC patients, ΔrSO2 was 22 ± 16% vs. 7 ± 10% in non-ROSC patients (p = .009). A rSO2 threshold of 36% predicted ROSC with a sensitivity of 67% and specificity of 69% while ΔrSO2 of 7% showed a sensitivity of 100% and a specificity of 86% (AUC = 0.733 and 0.893, respectively). Mean rSO2 of 47 ± 11% was associated with favourable and 38 ± 12% with poor neurological outcome. There was, however, a great overlap between groups due to scarce data.

CONCLUSION

Higher rSO2 consistently correlated with increased rates of ROSC. The discriminatory power of rSO2 to prognosticate favourable neurological outcome remains unclear. Measuring rSO2 during CPR could potentially facilitate clinical decision-making.

Corpuls CPR Generates Higher Mean Arterial Pressure Than LUCAS II in a Pig Model of Cardiac Arrest

According to the European Resuscitation Council guidelines, the use of mechanical chest compression devices is a reasonable alternative in situations where manual chest compression is impractical or compromises provider safety. The aim of this study is to compare the performance of a recently developed chest compression device (Corpuls CPR) with an established system (LUCAS II) in a pig model. Methods. Pigs (n = 5/group) in provoked ventricular fibrillation were left untreated for 5 minutes, after which 15 min of cardiopulmonary resuscitation was performed with chest compressions. After 15 min, defibrillation was performed every 2 min if necessary, and up to 3 doses of adrenaline were given. If there was no return of spontaneous circulation after 25 min, the experiment was terminated. Coronary perfusion pressure, carotid blood flow, end-expiratory CO₂, regional oxygen saturation by near infrared spectroscopy, blood gas, and local organ perfusion with fluorescent labelled microspheres were measured at baseline and during resuscitation. Results. Animals treated with Corpuls CPR had significantly higher mean arterial pressures during resuscitation, along with a detectable trend of greater carotid blood flow and organ perfusion. Conclusion. Chest compressions with the Corpuls CPR device generated significantly higher mean arterial pressures than compressions performed with the LUCAS II device.

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.

Accidental hypothermia-an update : The content of this review is endorsed by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM)

BACKGROUND

This paper provides an up-to-date review of the management and outcome of accidental hypothermia patients with and without cardiac arrest.

METHODS

The authors reviewed the relevant literature in their specialist field. Summaries were merged, discussed and approved to produce this narrative review.

RESULTS

The hospital use of minimally-invasive rewarming for non-arrested, otherwise healthy, patients with primary hypothermia and stable vital signs has the potential to substantially decrease morbidity and mortality for these patients. Extracorporeal life support (ECLS) has revolutionised the management of hypothermic cardiac arrest, with survival rates approaching 100 % in some cases. Hypothermic patients with risk factors for imminent cardiac arrest (temperature <28 °C, ventricular arrhythmia, systolic blood pressure <90 mmHg), and those who have already arrested, should be transferred directly to an ECLS-centre. Cardiac arrest patients should receive continuous cardiopulmonary resuscitation (CPR) during transfer. If prolonged transport is required or terrain is difficult, mechanical CPR can be helpful. Delayed or intermittent CPR may be appropriate in hypothermic arrest when continuous CPR is impossible. Modern post-resuscitation care should be implemented following hypothermic arrest. Structured protocols should be in place to optimise pre-hospital triage, transport and treatment as well as in-hospital management, including detailed criteria and protocols for the use of ECLS and post-resuscitation care.

CONCLUSIONS

Based on new evidence, additional clinical experience and clearer management guidelines and documentation, the treatment of accidental hypothermia has been refined. ECLS has substantially improved survival and is the treatment of choice in the patient with unstable circulation or cardiac arrest.

Near-infrared Spectroscopy Monitoring During Cardiac Arrest: A Systematic Review and Meta-analysis

BACKGROUND

Tissue oximetry using near-infrared spectroscopy (NIRS) is a noninvasive monitor of cerebral oxygenation. This new technology has been used during cardiac arrest (CA) because of its ability to give measures in low-blood-flow situations. The aim of this study was to assess the evidence regarding the association between the types of NIRS measurements (mean, initial, and highest values) and resuscitation outcomes (return of spontaneous circulation [ROSC], survival to discharge, and good neurologic outcome) in patients undergoing cardiopulmonary resuscitation.

METHODS

This review was registered (Prospero CRD42015017380) and is reported as per the PRISMA guidelines. Medline, Embase, and CENTRAL were searched. All studies, except case reports and case series of fewer than five patients, reporting on adults that had NIRS monitoring during CA were eligible for inclusion. Two reviewers assessed the quality of the included articles and extracted the data. The outcome effect was standardized using standardized mean difference (SMD).

RESULTS

Twenty nonrandomized observational studies (15 articles and five conference abstracts) were included in this review, for a total of 2,436 patients. We found a stronger association between ROSC and mean NIRS values (SMD = 1.33; 95% confidence interval [CI] = 0.92 to 1.74) than between ROSC and initial NIRS measurements (SMD = 0.51; 95% CI = 0.23 to 0.78). There was too much heterogeneity among the highest NIRS measurements group to perform meta-analysis. Only two of the 75 patients who experienced ROSC had a mean NIRS saturation under 30%. Patients who survived to discharge and who had good neurologic outcome displayed superior combined initial and mean NIRS values than their counterparts (SMD = 1.63; 95% CI = 1.34 to 1.92; and SMD = 2.12; 95% CI = 1.14 to 3.10).

CONCLUSIONS

Patients with good resuscitation outcomes have significantly higher NIRS saturations during resuscitation than their counterparts. The types of NIRS measurements during resuscitation influenced the association between ROSC and NIRS saturation. Prolonged failure to obtain a NIRS saturation higher than 30% may be included in a multimodal approach to the decision of terminating resuscitation efforts (Class IIb, Level of Evidence C-Limited Data).

Good neurological outcome despite very low regional cerebral oxygen saturation during resuscitation--a prospective preclinical trial in 29 patients

Background

Noninvasive regional cerebral oxygen saturation (rSO₂) measurement using near-infrared spectroscopy (NIRS) might inform on extent and duration of cerebral hypoxia during cardiopulmonary resuscitation (CPR). This information may be used to guide resuscitation efforts and may carry relevant early prognostic information.

Methods

We prospectively investigated non-traumatic out-of-hospital cardiac arrest (OHCA) patients on scene. NIRS was started either during CPR or shortly after (<2 min) return of spontaneous circulation (ROSC) by emergency medical service (EMS). Outcome was determined at intensive care unit (ICU) discharge and 6 months after cardiac arrest.

Results

A total of 29 OHCA patients were included. In 23 patients NIRS was started during CPR and in 6 patients immediately after ROSC. 18 (62.1 %) patients did not reach ROSC. Initial rSO₂ during CPR was very low (<50 % in all 23 patients, < 30 % in 19 of 23 patients) with no significant difference between patients achieving ROSC and those who did not. Of five patients with ROSC, in whom NIRS was recorded during CPR, two reached a good six-months outcome (initial rSO₂ 22 %) and three died during the ICU stay (initial rSO₂ 15, 16 and 46 %). In six patients with NIRS started immediately after ROSC (<2 min), rSO2 was substantially higher (54–85 %) than in patients during CPR (p = 0.006).

Discussion and conclusion

Initial frontal brain rSO₂ determined by NIRS during CPR was generally very low and recovered rapidly after ROSC. Very low initial rSO₂ during CPR was compatible with good neurological outcome in our limited cohort of patients. Further studies are needed to assess in larger cohorts and more detail the implications of very low initial rSO₂ during CPR on scene.

Systematic review and meta-analysis of hemodynamic-directed feedback during cardiopulmonary resuscitation in cardiac arrest

BACKGROUND/OBJECTIVE

Physiologic monitoring of resuscitative efforts during cardiac arrest is gaining in importance, as it provides a real-time window into the cellular physiology of patients. The aim of this review is to assess the quality of evidence surrounding the use of physiologic monitoring to guide cardiopulmonary resuscitation (CPR), and to examine whether the evidence demonstrates an improvement in patient outcome when comparing hemodynamic-directed CPR versus standard CPR.

METHODS

Studies were obtained through a search of the PubMed, Embase and Cochrane databases. Peer-reviewed randomized trials, case-control studies, systematic reviews, and cohort studies that titrated CPR to physiologic measures, compared results to standard CPR, and examined patient outcome were included.

RESULTS

Six studies met inclusion criteria, with all studies conducted in animal populations. Four studies examined the effects of hemodynamic-directed CPR on survival, with 35/37 (94.6%) animals surviving in the hemodynamic-directed CPR groups and 12/35 (34.3%) surviving in the control groups (p<0.001). Two studies examined the effects of hemodynamic-directed CPR on ROSC, with 22/30 (73.3%) achieving ROSC in the hemodynamic-directed CPR group and 19/30 (63.3%) achieving ROSC in the control group (p=0.344).

DISCUSSION/CONCLUSION

These results suggest a trend in survival from hemodynamic-directed CPR over standard CPR, however the small sample size and lack of human data make these results of limited value. Future human studies examining hemodynamic-directed CPR versus current CPR standards are needed to enhance our understanding of how to effectively use physiologic measures to improve resuscitation efforts and ultimately incorporate concrete targets into international resuscitation guidelines.

Ventilation and gas exchange management after cardiac arrest

For several decades, physicians had integrated several interventions aiming to improve the outcomes in post-cardiac arrest patients. However, the mortality rate after cardiac arrest is still as high as 50%. Post-cardiac arrest syndrome is associated with high morbidity and mortality due to not only poor neurological outcome and cardiovascular failure but also respiratory dysfunction. To minimize ventilator-associated lung injury, protective mechanical ventilation by using low tidal volume ventilation and driving pressure may decrease pulmonary complications and improve survival. Low level of positive end-expiratory pressure (PEEP) can be initiated and titrated with careful cardiac output and respiratory mechanics monitoring. Furthermore, optimizing gas exchange by avoiding hypoxia and hyperoxia as well as maintaining normocarbia may improve neurological and survival outcome. Early multidisciplinary cardiac rehabilitation intervention is recommended. Minimally invasive monitoring techniques, that is, echocardiography, transpulmonary thermodilution method measuring extravascular lung water, as well as transcranial Doppler ultrasound, might be useful to improve appropriate management of post-cardiac arrest patients.

Cerebral Oximetry as a Real-Time Monitoring Tool to Assess Quality of In-Hospital Cardiopulmonary Resuscitation and Post Cardiac Arrest Care

Background

Regional cerebral oxygen saturation (rSO₂) as assessed by near infrared frontal cerebral spectroscopy decreases in circulatory arrest and increases with high-quality cardiopulmonary resuscitation. We hypothesized that higher rSO₂ during cardiopulmonary resuscitation and after return of spontaneous circulation (ROSC) would predict survival to discharge and neurological recovery.

Methods and Results

This prospective case series included patients experiencing in-hospital cardiac arrest. Cerebral oximetry was recorded continuously from initiation of resuscitation until ROSC and up to 48 hours post-arrest. Relationships between oximetry data during these time periods and outcomes of resuscitation survival and survival to discharge were analyzed. The cohort included 27 patients. Nineteen (70.3%) achieved ROSC, and 8 (29.6%) survived to discharge. Median arrest duration was 20.8 minutes (range =8 to 74). There was a significant difference in rSO₂ between resuscitation survivors and resuscitation nonsurvivors at initiation of the resuscitative efforts (35% versus 17.5%, P =0.03) and during resuscitation (36% versus 15%, P =0.0008). No significant association was observed between rSO₂ at ROSC or during the post-arrest period and survival to discharge. Among patients who survived to discharge, there was no association between cerebral performance category and rSO₂ at ROSC, during resuscitation, or post-arrest.

Conclusions

Higher rSO₂ levels at initiation of resuscitation and during resuscitation are associated with resuscitation survival and may reflect high-quality cardiopulmonary resuscitation. However, in this small series, rSO₂ was not predictive of good neurological outcome. Larger studies are needed to determine whether this monitoring modality can be used to improve clinical outcomes.

Characteristics of regional cerebral oxygen saturation levels in patients with out-of-hospital cardiac arrest with or without return of spontaneous circulation: A prospective observational multicentre study

AIM

Our study aimed at filling the fundamental knowledge gap on the characteristics of regional brain oxygen saturation (rSO2) levels in out-of-hospital cardiac arrest (OHCA) patients with or without return of spontaneous circulation (ROSC) upon arrival at the hospital for estimating the quality of cardiopulmonary resuscitation and neurological prognostication in these patients.

METHODS

We enrolled 1921 OHCA patients from the Japan - Prediction of Neurological Outcomes in Patients Post-cardiac Arrest Registry and measured their rSO2 immediately upon arrival at the hospital by near-infrared spectroscopy using two independent forehead probes (right and left). We also assessed the percentage of patients with a good neurological outcome (defined as cerebral performance categories 1 or 2) 90 days post cardiac arrest.

RESULTS

After 90 days, 79 (4%) patients had good neurological outcomes and a median lower rSO2 level of 15% (15-20%). Compared to patients without ROSC upon arrival at the hospital, those with ROSC had significantly higher rSO2 levels (56% [39-65%] vs. 15% [15-17%], respectively; P<0.01), and significantly correlated right- and left-sided regional brain oxygen saturation levels (R=0.94 vs. 0.66, respectively). In both groups, the percentage of patients with a good 90-day neurological outcome increased significantly in proportion to their rSO2 levels upon arrival at the hospital (P<0.01).

CONCLUSION

Our data indicate that measuring rSO2 levels might be effective for both monitoring the quality of resuscitation and neurological prognostication in patients with OHCA.

[Near-infrared spectroscopy during cardiopulmonary resuscitation and mechanical circulatory support: From the operating room to the intensive care unit]

BACKGROUND

Near infrared spectroscopy (NIRS) allows continuous measurement of cerebral regional oxygen saturation (rSO2). It is a weighted saturation value derived from approximately 70-75 % venous, 20-25 % arterial and 2.5-5 % capillary blood. In contrast to pulse oximetry, NIRS is independent of pulsatile flow. Therefore, it is also applicable during extracorporeal circulation, cardiopulmonary resuscitation (CPR), and hypothermia.

OBJECTIVES

The purpose of this work is to describe the application of cerebral and somatic NIRS in cardiology and cardiac surgery patients in the operation room, during and after CPR, and during the intensive care unit stay.

MATERIALS AND METHODS

This article is based on peer-reviewed literature from PubMed.

RESULTS

Interventions based on decline of cerebral NIRS values during on-pump cardiac surgery can reduce major organ morbidity and mortality; however, the appearance of a postoperative cognitive dysfunction is scarcely influenced. Persisting of low cerebral oximetry values during resuscitation is a marker for not achieving return of spontaneous circulation under normothermia. NIRS is an additional method for monitoring that can be used during extracorporeal circulation.

CONCLUSION

NIRS is a rapidly available, user-friendly, and noninvasive method for continuous measurement of rSO2. NIRS provides additional information about tissue oxygenation especially during resuscitation and extracorporeal circulatory assist support. Recommendations concerning the use of NIRS for standard monitoring during resuscitation and mechanical circulatory support are not currently available. Further studies are required to show if use of NIRS can reduce pulse control and hands-off times during resuscitation and if use of NIRS can improve outcome after CPR and mechanical circulatory support.

Increase in cerebral oxygenation during advanced life support in out-of-hospital patients is associated with return of spontaneous circulation

Introduction

By maintaining sufficient cerebral blood flow and oxygenation, the goal of cardiopulmonary resuscitation (CPR) is to preserve the pre-arrest neurological state. To date, cerebral monitoring abilities during CPR have been limited. Therefore, we investigated the time-course of cerebral oxygen saturation values (rSO₂) during advanced life support in out-of-hospital cardiac arrest. Our primary aim was to compare rSO₂ values during advanced life support from patients with return of spontaneous circulation (ROSC) to patients who did not achieve ROSC.

Methods

We performed an observational study to measure rSO₂ using Equanox™ (Nonin, Plymouth, MI) from the start of advanced life support in the pre-hospital setting.

Results

rSO₂ of 49 consecutive out-of-hospital cardiac arrest patients were analyzed. The total increase from initial rSO₂ value until two minutes before ROSC or end of advanced life support efforts was significantly larger in the group with ROSC 16% (9 to 36) compared to the patients without ROSC 10% (4 to 15) (P = 0.02). Mean rSO₂ from the start of measurement until two minutes before ROSC or until termination of advanced life support was higher in patients with ROSC than in those without, namely 39% ± 7 and 31% ± 4 (P = 0.05) respectively.

Conclusions

During pre-hospital advanced life support, higher increases in rSO₂ are observed in patients attaining ROSC, even before ROSC was clinically determined. Our findings suggest that rSO₂ could be used in the future to guide patient tailored treatment during cardiac arrest and could therefore be a surrogate marker of the systemic oxygenation state of the patient.

Photoplethysmography-based algorithm for detection of cardiogenic output during cardiopulmonary resuscitation

Detecting return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR) is challenging, time consuming, and requires interrupting chest compressions. Based on automated-CPR porcine data, we have developed an algorithm to support ROSC detection, which detects cardiogenic output during chest compressions via a photoplethysmography (PPG) signal. The algorithm can detect palpable and impalpable spontaneous pulses. A compression-free PPG signal which estimates the spontaneous pulse waveform, was obtained by subtracting the compression component, modeled by a harmonic series. The fundamental frequency of this series was the compression rate derived from the transthoracic impedance signal measured between the defibrillation pads. The amplitudes of the harmonic components were obtained via a least mean-square algorithm. The frequency spectrum of the compression-free PPG signal was estimated via an autoregressive model, and the relationship between the spectral peaks was analyzed to identify the pulse rate (PR). Resumed cardiogenic output could also be detected from a decrease in the baseline of the PPG signal, presumably caused by a redistribution of blood volume to the periphery. The algorithm indicated cardiogenic output when a PR or a redistribution of blood volume was detected. The algorithm indicated cardiogenic output with 94% specificity and 69% sensitivity compared to the retrospective ROSC detection of nine clinicians. Results showed that ROSC detection can be supported by combining the compression-free PPG signal with an indicator based on the detected PR and redistribution of blood volume.

Portable system for monitoring of regional cerebral oxygen saturation during prehospital cardiopulmonary resuscitation: a pilot study

Aim

We aimed to create a system for monitoring of regional cerebral oxygen saturation (rSO ₂) in patients with prehospital cardiopulmonary arrest and clarify the changes in rSO ₂ during cardiopulmonary resuscitation.

Methods

We measured rSO ₂ in cardiopulmonary arrest patients who were transferred by the emergency response vehicle of Nagasaki University Hospital. We developed a portable rSO ₂ monitor (HAND ai TOS), which is small enough to carry during prehospital treatment. The sensor is attached to the forehead of the patient and monitors rSO ₂ continuously during treatment and transfer.

Results

No difficulties were experienced in monitoring rSO ₂ during patient treatment and transfer. Median time (interquartile range) from the emergency medical service call to emergency response vehicle arrival was 15.0 min (11.0-19.5 min). Median rSO ₂ on emergency response vehicle arrival at the scene was 46.3% (44.0-48.2%) (n = 9; median age, 74.0 years; four men, five women). Median rSO ₂ showed significant increase within 5 min after return of spontaneous circulation (n = 6, 46.6% versus 58.7%, P < 0.05). There was no significant increase in rSO ₂ during prehospital cardiopulmonary resuscitation until return of spontaneous circulation was established.

Conclusions

We developed an rSO ₂ monitoring system for use during prehospital cardiopulmonary resuscitation. The monitoring system showed a significant increase in rSO ₂ after return of spontaneous circulation, whereas there was no significant increase in rSO ₂ during cardiopulmonary resuscitation after intubation but before return of spontaneous circulation.