Cerebral oximetry and 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.

Cerebral Oximetry During Pediatric In-Hospital Cardiac Arrest: A Multicenter Study of Survival and Neurologic Outcome

OBJECTIVES

To determine if near-infrared spectroscopy measuring cerebral regional oxygen saturation (crS o2 ) during cardiopulmonary resuscitation is associated with return of spontaneous circulation (ROSC) and survival to hospital discharge (SHD) in children.

DESIGN

Multicenter, observational study.

SETTING

Three hospitals in the pediatric Resuscitation Quality (pediRES-Q) collaborative from 2015 to 2022.

PATIENTS

Children younger than 18 years, gestational age 37 weeks old or older with in-hospital cardiac arrest (IHCA) receiving cardiopulmonary resuscitation greater than or equal to 1 minute and intra-arrest crS o2 monitoring.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was ROSC greater than or equal to 20 minutes without extracorporeal membrane oxygenation. Secondary outcomes included SHD and favorable neurologic outcome (FNO) (Pediatric Cerebral Performance Category 1-2 or no change from prearrest). Among 3212 IHCA events (index and nonindex), 123 met inclusion criteria in 93 patients. Median age was 0.3 years (0.1-1.4 yr) and 31% (38/123) of the cardiopulmonary resuscitation events occurred in patients with cyanotic heart disease. Median cardiopulmonary resuscitation duration was 8 minutes (3-28 min) and ROSC was achieved in 65% (80/123). For index events, SHD was achieved in 59% (54/91) and FNO in 41% (37/91). We determined the association of median intra-arrest crS o2 and percent of crS o2 values above a priori thresholds during the: 1) entire cardiopulmonary resuscitation event, 2) first 5 minutes, and 3) last 5 minutes with ROSC, SHD, and FNO. Higher crS o2 for the entire cardiopulmonary resuscitation event, first 5 minutes, and last 5 minutes were associated with higher likelihood of ROSC, SHD, and FNO. In multivariable analysis of the infant group (age < 1 yr), higher crS o2 was associated with ROSC (odds ratio [OR], 1.06; 95% CI, 1.03-1.10), SHD (OR, 1.04; 95% CI, 1.01-1.07), and FNO (OR, 1.05; 95% CI, 1.02-1.08) after adjusting for presence of cyanotic heart disease.

CONCLUSIONS

Higher crS o2 during pediatric IHCA was associated with increased rate of ROSC, SHD, and FNO. Intra-arrest crS o2 may have a role as a real-time, noninvasive predictor of ROSC.

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.

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.

A case report: use of cerebral oximetry in the early detection of cerebral hypoperfusion in a post-cardiac arrest patient during targeted temperature management

BACKGROUND

We present a patient who received cerebral oximetry monitoring during targeted temperature management (TTM) post-cardiac arrest and discuss its potential in the early detection of cerebral hypoperfusion and implications on haemodynamics and ventilatory management.

CASE SUMMARY

A 60-year-old Chinese male was admitted for acute pulmonary oedema with Type 2 respiratory failure. He failed an initial trial of non-invasive ventilation and was planned for intubation and mechanical ventilation. However, the patient suffered a pulseless electrical activity cardiac arrest peri-intubation. He was started on our institution's protocolized post-cardiac arrest care bundle, which included cerebral regional oxygen saturation (rSO₂) monitoring and TTM. Initial arterial blood gas (ABG) post-return of spontaneous circulation showed severe respiratory acidosis, and the patient was sedated, paralyzed, and ventilator settings optimized. Repeat ABG showed resolution of respiratory acidosis. However, a drop in rSO₂ to 35% was subsequently noted. Ventilator settings were quickly adjusted, and dobutamine was started to improve global and cerebral perfusion. These measures improved cerebral rSO₂ to more than 50%. Patient was cooled for 24 h and gradually rewarmed. He was later extubated with a cerebral performance category of 1 and is now on outpatient follow-up.

DISCUSSION

During post-cardiac arrest care, there are many factors which can contribute to a decrease in cerebral blood flow. Therapeutic hypothermia and ventilation strategies, including the use of neuromuscular blocking agents, can both reduce pCO₂ which is a major regulator of cerebrovascular tone. Accidental hypocapnia can lead to adverse cerebral vasoconstriction and hypoperfusion. Without cerebral oximetry, cerebral ischaemia may not be detected early and can potentially result in secondary brain injury.

End tidal CO2 and cerebral oximetry for the prediction of return of spontaneous circulation during cardiopulmonary resuscitation

BACKGROUND

End Tidal CO₂ (ETCO₂) is a reasonable predictor of Return of Spontaneous Circulation (ROSC) in cardiac arrest (CA), though with many limitations. Cerebral Oximetry (CerOx) non-invasively measures brain O₂ saturation and correlates with flow.

OBJECTIVES

This study compares ETCO₂ and CerOx for ROSC prediction during both out of hospital (OHCA) and emergency department cardiac arrests (EDCA).

METHODS

We conducted a prospective study on CA patients resuscitated in the ED. ETCO₂ and CerOx simultaneously measured during ED CPR. Data was analyzed with logistic regression modeling and area under the curve (AUC).

RESULTS

176 patients were analyzed, 66.7% were witnessed, 52.8% had bystander CPR. EMS alert to ED arrival was 27.0 ± 10.6 min. Initial rhythm was 31.8% asystole, 27.8% PEA, 25.6% VF/VT with 26.1% achieving ROSC. AUC predictors of ROSC were: last 5 min trend [CerOx = 0.82 ; ETCO₂ = 0.74], delta first to last [CerOx = 0.86 ; ETCO₂ = 0.73], the penultimate minute [CerOx = 0.81 ; ETCO₂ = 0.76], and final minute [CerOx = 0.89 ; ETCO₂ = 0.77]. AUC comparison of simultaneous measurements (n = 125) revealed: last 5 min trend [CerOx = 0.80 ; ETCO₂ = 0.79], delta first to last [CerOx = 0.83 ; ETCO₂ = 0.75], penultimate minute [CerOx = 0.83 ETCO₂ = 0.74], and final minute [CerOx = 0.89 ; ETCO₂ = 0.75].

CONCLUSIONS

Our data shows, both ETCO2 and rSO2 are good predictors of ROSC. We found CerOx superior to ETCO₂ in predicting 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.

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.

The Year in Review

Congenital cardiac anesthesiology is a young and rapidly growing subspecialty. It embraces a large spectrum of congenital and acquired heart diseases, which now affect the entire life span of patients from “cradle to grave.” One of the challenges faced by congenital cardiac anesthesiologists is reading the large amount of relevant literature from the fields of cardiology, cardiac surgery, intensive care medicine, and anesthesiology. This review highlights some of the current themes in the literature during the past year.