Post-cardiac arrest syndrome: epidemiology, pathophysiology, treatment, and prognostication. A Scientific Statement from the International Liaison Committee on Resuscitation; the American Heart Association Emergency Cardiovascular Care Committee; the Council on Cardiovascular Surgery and Anesthesia; the Council on Cardiopulmonary, Perioperative, and Critical Care; the Council on Clinical Cardiology; the Council on Stroke

Under pressure - Association of the arm position and leading circulatory structure behind the pressure point in cardiopulmonary resuscitation patients

BACKGROUND

Thoracic computed tomography scans (CT) are used by several study groups to investigate the circulatory structures (heart and vessels) located behind the pressure point for chest compressions. Yet, it remains unclear how the positioning of these structures is influenced by factors such as intubation, the respiratory cycle and arm positioning.

METHODS

We retrospectively analyzed data of adult patients with in- or out-of-hospital cardiac arrest who underwent thoracic CT imaging within one year before or up to six months after arrest. A region of interest (ROI) behind the pressure point was defined. The largest structure within this region was defined as "leading circulatory structure", which was the primary outcome. Airway status (intubated versus spontaneous breathing), respiratory cycle (inspiration, expiration, resting expiratory position), and arm position (up over the head versus down beside the trunk) served as covariates in an ordinal regression model.

RESULTS

Among 500 initially screened patients, 411 (82.2 %) were included in the analysis. There was a significant association between the arm position and the leading circulatory structure behind the pressure point. However, no association was found with airway status or respiratory cycle. The most frequently identified leading circulatory structure was the left atrium (arms up: 41.8 %, down: 50.7 %), followed by the ascending aorta (up: 23.8 % vs. down: 16.7 %). The left ventricle was the leading structure in only one case (0.2 %, arms down).

CONCLUSION

This study shows that arm position is significantly associated with the leading circulatory structure behind the pressure point for chest compressions in cardiac arrest.

Sulforaphane improves post-resuscitation myocardial dysfunction by inhibiting cardiomyocytes ferroptosis via the Nrf2/IRF1/GPX4 pathway

BACKGROUND

Ferroptosis is an important type of cell death contributing to myocardial dysfunction induced by whole body ischemia reperfusion following cardiac arrest (CA) and resuscitation. Sulforaphane (SFN), known as the activator of the nuclear factor E2-related factor 2 (Nrf2), has been proven to effectively alleviate regional myocardial ischemia reperfusion injury. The present study was designed to investigate whether SFN could improve post-resuscitation myocardial dysfunction by inhibiting cardiomyocytes ferroptosis and its potential regulatory mechanism.

METHODS AND RESULTS

An in vivo pig model of CA and resuscitation was established. Hypoxia/reoxygenation (H/R)-stimulated AC16 cardiomyocytes was constructed as an in vitro model to simulate the process of CA and resuscitation. In vitro experiment, SFN reduced ferroptosis-related ferrous iron, lipid reactive oxygen species, and malondialdehyde, increased glutathione, and further promoted cell survival after H/R stimulation in AC16 cardiomyocytes. Mechanistically, the activation of Nrf2 with the SFN decreased interferon regulatory factor 1 (IRF1) expression, then reduced its binding to the promoter of glutathione peroxidase 4 (GPX4), and finally recovered the latter's transcription after H/R stimulation in AC16 cardiomyocytes. In vivo experiment, SFN reversed abnormal expression of IRF1 and GPX4, inhibited cardiac ferroptosis, and improved myocardial dysfunction after CA and resuscitation in pigs.

CONCLUSIONS

SFN could effectively improve myocardial dysfunction after CA and resuscitation, in which the mechanism was potentially related to the inhibition of cardiomyocytes ferroptosis through the regulation of Nrf2/IRF1/GPX4 pathway.

Cardiac arrest and microcirculatory dysfunction: a narrative review

PURPOSE OF REVIEW

This review provides an overview of the role of microcirculation in cardiac arrest and postcardiac arrest syndrome through handheld intravital microscopy and biomarkers. It highlights the importance of microcirculatory dysfunction in postcardiac arrest outcomes and explores potential therapeutic targets.

RECENT FINDINGS

Sublingual microcirculation is impaired in the early stage of postarrest and is potentially associated with increased mortality. Recent work suggests that the proportion of perfused small vessels is predictive of mortality. Microcirculatory impairment is consistently found to be independent of macrohemodynamic parameters. Biomarkers of endothelial cell injury and endothelial glycocalyx degradation are elevated in postarrest settings and may predict mortality and clinical outcomes, warranting further studies. Recent studies of exploratory therapies targeting microcirculation have shown some promise in animal models but still require significant research.

SUMMARY

Although research continues to suggest the important role that microcirculation may play in postcardiac arrest syndrome and cardiac arrest outcomes, the existing studies are still limited to draw any definitive conclusions. Further research is needed to better understand microcirculatory changes and their significance to improve cardiac arrest care and outcomes.

Endogenous orexin and hyperacute autonomic responses after resuscitation in a preclinical model of cardiac arrest

Objectives

The study of autonomic responses to cardiac arrest (CA) resuscitation deserves attention due to the impact of autonomic function on survival and arousal. Orexins are known to modulate autonomic function, but the role of endogenous orexin in hyperacute recovery of autonomic function post-resuscitation is not well understood. We hypothesized that endogenous orexin facilitates hyperacute cardiovascular sympathetic activity post-resuscitation, and this response could be attenuated by suvorexant, a dual orexin receptor antagonist.

Methods

A well-established 7-min asphyxial CA rat model was studied. Heart rate (HR) and blood pressure were monitored from baseline to 90-min post-resuscitation. Autonomic function was evaluated by spectral analysis of HR variability, whereby the ratio of low- and high-frequency components (LF/HF ratio) represents the balance between sympathetic/parasympathetic activities. Plasma orexin-A levels and orexin receptors immunoreactivity in the rostral ventrolateral medulla (RVLM), the key central region for regulating sympathetic output, were measured post-resuscitation. Neurological outcome was assessed via neurologic-deficit score at 4-h post-resuscitation.

Key results

A significant increase in HR was found over 25-40 min post-resuscitation (p < 0.01 vs. baseline), which was attenuated by suvorexant significantly (p < 0.05). Increased HR (from 15-to 25-min post-resuscitation) was correlated with better neurological outcomes (rs = 0.827, p = 0.005). There was no evident increase in mean arterial pressure over 25-40 min post-resuscitation, while systolic pressure was reduced greatly by suvorexant (p < 0.05). The LF/HF ratio was higher in animals with favorable outcomes than in animals injected with suvorexant over 30-40 min post-resuscitation (p < 0.05). Plasma orexin-A levels elevated at 15-min and peaked at 30-min post-resuscitation (p < 0.01 vs. baseline). Activated orexin receptors-immunoreactive neurons were found co-stained with tyrosine hydroxylase-immunopositive cells in the RVLM at 2-h post-resuscitation.

Conclusion

Together, increased HR and elevated LF/HF ratio indicative of sympathetic arousal during a critical window (25-40 min) post-resuscitation are observed in animals with favorable outcomes. The orexin system appears to facilitate this hyperacute autonomic response post-CA.

The association between initial post-resuscitation diastolic blood pressure and survival after pediatric cardiac arrest: a retrospective study

BACKGROUND

Limited research has analyzed the association between diastolic blood pressure (DBP) and survival after pediatric cardiopulmonary resuscitation (CPR). This study aimed to explore the association between post-resuscitation diastolic blood pressure and survival in pediatric patients who underwent CPR.

METHOD

This retrospective single-center study included pediatric patients admitted to the pediatric intensive care unit of Asan Medical Center between January 2016 to November 2022. Patients undergoing extracorporeal CPR and those with unavailable data were excluded. The primary endpoint was survival to ICU discharge.

RESULTS

A total of 106 patients were included, with 67 (63.2%) achieving survival to ICU discharge. Multivariate logistic regression analysis identified DBP within 1 h after ROSC as the sole significant variable (p = 0.002, aOR, 1.043; 95% CI, 1.016-1.070). Additionally, DBP within 1 h demonstrated an area under the ROC curve of 0.7 (0.592-0.809) for survival to ICU discharge, along with mean blood pressure within the same timeframe.

CONCLUSION

Our study highlights the importance of DBP within 1-hour post-ROSC as a significant prognostic factor for survival to ICU discharge. However, further validation through further prospective large-scale studies is warranted to confirm the appropriate post-resuscitation DBP of pediatric patients.

Association of Postarrest Hypotension Burden With Unfavorable Neurologic Outcome After Pediatric Cardiac Arrest

OBJECTIVE

Quantify hypotension burden using high-resolution continuous arterial blood pressure (ABP) data and determine its association with outcome after pediatric cardiac arrest.

DESIGN

Retrospective observational study.

SETTING

Academic PICU.

PATIENTS

Children 18 years old or younger admitted with in-of-hospital or out-of-hospital cardiac arrest who had invasive ABP monitoring during postcardiac arrest care.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

High-resolution continuous ABP was analyzed up to 24 hours after the return of circulation (ROC). Hypotension burden was the time-normalized integral area between mean arterial pressure (MAP) and fifth percentile MAP for age. The primary outcome was unfavorable neurologic status (pediatric cerebral performance category ≥ 3 with change from baseline) at hospital discharge. Mann-Whitney U tests compared hypotension burden, duration, and magnitude between favorable and unfavorable patients. Multivariable logistic regression determined the association of unfavorable outcomes with hypotension burden, duration, and magnitude at various percentile thresholds from the 5th through 50th percentile for age. Of 140 patients (median age 53 [interquartile range 11-146] mo, 61% male); 63% had unfavorable outcomes. Monitoring duration was 21 (7-24) hours. Using a MAP threshold at the fifth percentile for age, the median hypotension burden was 0.01 (0-0.11) mm Hg-hours per hour, greater for patients with unfavorable compared with favorable outcomes (0 [0-0.02] vs. 0.02 [0-0.27] mm Hg-hr per hour, p < 0.001). Hypotension duration and magnitude were greater for unfavorable compared with favorable patients (0.03 [0-0.77] vs. 0.71 [0-5.01]%, p = 0.003; and 0.16 [0-1.99] vs. 2 [0-4.02] mm Hg, p = 0.001). On logistic regression, a 1-point increase in hypotension burden below the fifth percentile for age (equivalent to 1 mm Hg-hr of burden per hour of recording) was associated with increased odds of unfavorable outcome (adjusted odds ratio [aOR] 14.8; 95% CI, 1.1-200; p = 0.040). At MAP thresholds of 10th-50th percentiles for age, MAP burden below the threshold was greater in unfavorable compared with favorable patients in a dose-dependent manner.

CONCLUSIONS

High-resolution continuous ABP data can be used to quantify hypotension burden after pediatric cardiac arrest. The burden, duration, and magnitude of hypotension are associated with unfavorable neurologic outcomes.

Adenosine 2A Receptor Agonism Improves Survival in Extracorporeal Cardiopulmonary Resuscitation

INTRODUCTION

Despite resuscitation advances including extracorporeal cardiopulmonary resuscitation (ECPR), freedom from neurologic and myocardial insult after cardiac arrest remains unlikely. We hypothesized that adenosine 2A receptor (A2AR) agonism, which attenuates reperfusion injury, would improve outcomes in a porcine model of ECPR.

METHODS

Adult swine underwent 20 min of circulatory arrest followed by defibrillation and 6 h of ECPR. Animals were randomized to receive saline vehicle or A2AR agonist (ATL1223 or Regadenoson) infusion during extracorporeal membrane oxygenation. Animals were weaned off extracorporeal membrane oxygenation and monitored for 24 h. Clinical and biochemical end points were compared.

RESULTS

The administration of A2AR agonists increased survival (P = 0.01) after cardiac arrest compared to vehicle. Markers of neurologic damage including S100 calcium binding protein B and glial fibrillary acidic protein were significantly lower with A2AR agonist treatment.

CONCLUSIONS

In a model of cardiac arrest treated with ECPR, A2AR agonism increased survival at 24 h and reduced neurologic damage suggesting A2AR activation may be a promising therapeutic target after cardiac arrest.

Validating quantitative pupillometry thresholds for neuroprognostication after out-of-hospital cardiac arrest. A predefined substudy of the Blood Pressure and Oxygenations Targets After Cardiac Arrest (BOX)-trial

PURPOSE

Out-of-hospital cardiac arrest (OHCA) survivors face significant risks of complications and death from hypoxic-ischemic brain injury leading to withdrawal of life-sustaining treatment (WLST). Accurate multimodal neuroprognostication, including automated pupillometry, is essential to avoid inappropriate WLST. However, inconsistent study results hinder standardized threshold recommendations. We aimed to validate proposed pupillometry thresholds with no false predictions of unfavorable outcomes in comatose OHCA survivors.

METHODS

In the multi-center BOX-trial, quantitative measurements of automated pupillometry (quantitatively assessed pupillary light reflex [qPLR] and Neurological Pupil index [NPi]) were obtained at admission (0 h) and after 24, 48, and 72 h in comatose patients resuscitated from OHCA. We aimed to validate qPLR < 4% and NPi ≤ 2, predicting unfavorable neurological conditions defined as Cerebral Performance Category 3-5 at follow-up. Combined with 48-h neuron-specific enolase (NSE) > 60 μg/L, pupillometry was evaluated for multimodal neuroprognostication in comatose patients with Glasgow Motor Score (M) ≤ 3 at ≥ 72 h.

RESULTS

From March 2017 to December 2021, we consecutively enrolled 710 OHCA survivors (mean age: 63 ± 14 years; 82% males), and 266 (37%) patients had unfavorable neurological outcomes. An NPi ≤ 2 predicted outcome with 0% false-positive rate (FPR) at all time points (0-72 h), and qPLR < 4% at 24-72 h. In patients with M ≤ 3 at ≥ 72 h, pupillometry thresholds significantly increased the sensitivity of NSE, from 42% (35-51%) to 55% (47-63%) for qPLR and 50% (42-58%) for NPi, maintaining 0% (0-0%) FPR.

CONCLUSION

Quantitative pupillometry thresholds predict unfavorable neurological outcomes in comatose OHCA survivors and increase the sensitivity of NSE in a multimodal approach at ≥ 72 h.

Ultrafast Cooling With Total Liquid Ventilation Mitigates Early Inflammatory Response and Offers Neuroprotection in a Porcine Model of Cardiac Arrest

BACKGROUND

Brain injury is one of the most serious complications after cardiac arrest (CA). To prevent this phenomenon, rapid cooling with total liquid ventilation (TLV) has been proposed in small animal models of CA (rabbits and piglets). Here, we aimed to determine whether hypothermic TLV can also offer neuroprotection and mitigate cerebral inflammatory response in large animals.

METHODS AND RESULTS

Anesthetized pigs were subjected to 14 minutes of ventricular fibrillation followed by cardiopulmonary resuscitation. After return of spontaneous circulation, animals were randomly subjected to normothermia (control group, n=8) or ultrafast cooling with TLV (TLV group, n=8). In the latter group, TLV was initiated within a window of 15 minutes after return of spontaneous circulation and allowed to reduce tympanic, esophageal, and bladder temperature to the 32 to 34 °C range within 30 minutes. After 45 minutes of TLV, gas ventilation was resumed, and hypothermia was maintained externally until 3 hours after CA, before rewarming using heat pads (0.5 °C-1 °C/h). After an additional period of progressive rewarming for 3 hours, animals were euthanized for brain withdrawal and histological analysis. At the end of the follow-up (ie, 6 hours after CA), histology showed reduced brain injury as witnessed by the reduced number of Fluroro-Jade C-positive cerebral degenerating neurons in TLV versus control. IL (interleukin)-1ra and IL-8 levels were also significantly reduced in the cerebrospinal fluid in TLV versus control along with cerebral infiltration by CD3+ cells. Conversely, circulating levels of cytokines were not different among groups, suggesting a discrepancy between local and systemic inflammatory levels.

CONCLUSIONS

Ultrafast cooling with TLV mitigates neuroinflammation and attenuates acute brain lesions in the early phase following resuscitation in large animals subjected to CA.

Fifteen-minute consultation: A guide to paediatric post-resuscitation care following return of spontaneous circulation

Paediatric resuscitation is a key skill for anyone in medicine who is involved in the care of children. Basic and advance paediatric life support courses are crucial in teaching those skills nationwide in a way that is memorable, protocolised and standardised. These courses are vital in the dissemination and upkeep of both theoretical and practical knowledge of paediatric resuscitation, with their primary aim being the return of spontaneous circulation. While sustaining life is important, preserving a life with quality, one with good functional and neurological outcomes should be the gold standard of any resuscitative attempt. Good neurological outcomes are dependent, in large part, on how well the postresuscitation stage is managed. This stage does not start in the intensive care unit, it starts at the point at which spontaneous circulation has been reinstated. The aim of this paper is to provide a basic overview of the main strategies that should be followed in order to minimise secondary brain injury after successful resuscitation attempts.

Relationships of Jugular Bulb Parameters with Cerebral Perfusion and Metabolism After Resuscitation from Cardiac Arrest: A Post-Hoc Analysis of Experimental Studies Using a Minipig Model

BACKGROUND

Cerebral blood flow (CBF) decreases in the first few hours or days following resuscitation from cardiac arrest, increasing the risk of secondary cerebral injury. Using data from experimental studies performed in minipigs, we investigated the relationships of parameters derived from arterial and jugular bulb blood gas analyses and lactate levels (jugular bulb parameters), which have been used as indicators of cerebral perfusion and metabolism, with CBF and the cerebral lactate to creatine ratio measured with dynamic susceptibility contrast magnetic resonance imaging and proton magnetic resonance spectroscopy, respectively.

METHODS

We retrospectively analyzed 36 sets of the following data obtained during the initial hours following resuscitation from cardiac arrest: percent of measured CBF relative to that at the prearrest baseline (%CBF), cerebral lactate to creatine ratio, and jugular bulb parameters, including jugular bulb oxygen saturation, jugular bulb lactate, arterial-jugular bulb oxygen content difference, cerebral extraction of oxygen, jugular bulb-arterial lactate content difference, lactate oxygen index, estimated respiratory quotient, and arterial-jugular bulb hydrogen ion content difference. Linear mixed-effects models were constructed to examine the effects of each jugular bulb parameter on the %CBF and cerebral lactate to creatine ratio.

RESULTS

The arterial-jugular bulb oxygen content difference (P = 0.047) and cerebral extraction of oxygen (P = 0.030) had a significant linear relationship with %CBF, but they explained only 12.0% (95% confidence interval [CI] 0.002-0.371) and 14.2% (95% CI 0.005-0.396) of the total %CBF variance, respectively. The arterial-jugular bulb hydrogen ion content difference had a significant linear relationship with cerebral lactate to creatine ratio (P = 0.037) but explained only 13.8% (95% CI 0.003-0.412) of the total variance in the cerebral lactate to creatine ratio. None of the other jugular bulb parameters were related to the %CBF or cerebral lactate to creatine ratio.

CONCLUSIONS

In conclusion, none of the jugular bulb parameters appeared to provide sufficient information on cerebral perfusion and metabolism in this setting.

Bleeding complications, coagulation disorders, and their management in acute myocardial infarction-related cardiogenic shock rescued by veno-arterial ECMO: A retrospective cohort study

PURPOSE

Management of dual antiplatelet therapy (DAPT) in patients on venoarterial-extracorporeal membrane (VA-ECMO) after acute myocardial infarction (AMI) is challenging. Our objective was to describe the frequency, management and outcomes of severe bleeding complications and determine their occurrence risk factors.

MATERIAL AND METHODS

We conducted a retrospective observational cohort study including post-AMI cardiogenic shock patients requiring VA-ECMO. Severe bleeding was defined based on the Bleeding Academic Research Consortium classification. We calculated multivariable Fine-Gray models to assess factors associated with risk of severe bleeding.

RESULTS

From January 2015 to July 2019, 176 patients received VA-ECMO after AMI and 132 patients were included. Sixty-five (49%) patients died. Severe bleeding occurred in 39% of cases. Severe thrombocytopenia (< 50 G/L) and hypofibrinogenemia (<1,5 g/L) occurred in respectively 31% and 19% of patients. DAPT was stopped in 32% of patients with a 6% rate of stent thrombosis. Anticoagulation was stopped in 39% of patients. Using a multivariate competing risk model, female sex, time on ECMO, troponin at admission and Impella® implantation were independently associated with severe bleeding.

CONCLUSIONS

Bleeding complications and coagulation disorders were frequent and severe in patients on VA-ECMO after AMI, leading of antiplatelet therapy withdrawal in one third of patients.

Grey-to-White Matter Ratio Values in Early Head Computed Tomography (CT) as a Predictor of Neurologic Outcomes in Survivors of Out-of-Hospital Cardiac Arrest Based on Severity of Hypoxic-Ischemic Brain Injury

BACKGROUND

Hypoxic-ischemic brain injury (HIBI) is a common complication of out-of-hospital cardiac arrest (OHCA).

OBJECTIVES

We investigated whether grey-to-white matter ratio (GWR) values, measured using early head computed tomography (HCT), were associated with neurologic outcomes based on the severity of HIBI in survivors of OHCA.

METHODS

This retrospective multicenter study included adult comatose OHCA survivors who underwent an HCT scan within 2 h after the return of spontaneous circulation. HIBI severity was assessed using the revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) scale (low, moderate, and severe). Poor neurologic outcomes were defined as Cerebral Performance Categories 3 to 5 at 6 months after OHCA.

RESULTS

Among 354 patients, 27% were women and 224 (63.3%) had poor neurologic outcomes. The distribution of severity was 19.5% low, 47.5% moderate, and 33.1% severe. The area under the receiver operating curves of the GWR values for predicting rCAST severity (low, moderate, and severe) were 0.52, 0.62, and 0.79, respectively. The severe group had significantly higher predictive performance than the moderate group (p = 0.02). Multivariate logistic regression analysis revealed a significant association between GWR values and poor neurologic outcomes in the moderate group (adjusted odds ratio = 0.012, 95% CI 0.0-0.54, p = 0.02).

CONCLUSIONS

In this cohort study, GWR values measured using early HCT demonstrated variations in predicting neurologic outcomes based on HIBI severity. Furthermore, GWR in the moderate group was associated with poor neurologic outcomes.

The role of pyruvate-induced enhancement of oxygen metabolism in extracellular purinergic signaling in the post-cardiac arrest rat model

Purine nucleotide adenosine triphosphate (ATP) is a source of intracellular energy maintained by mitochondrial oxidative phosphorylation. However, when released from ischemic cells into the extracellular space, they act as death-signaling molecules (eATP). Despite there being potential benefit in using pyruvate to enhance mitochondria by inducing a highly oxidative metabolic state, its association with eATP levels is still poorly understood. Therefore, while we hypothesized that pyruvate could beneficially increase intracellular ATP with the enhancement of mitochondrial function after cardiac arrest (CA), our main focus was whether a proportion of the raised intracellular ATP would detrimentally leak out into the extracellular space. As indicated by the increased levels in systemic oxygen consumption, intravenous administrations of bolus (500 mg/kg) and continuous infusion (1000 mg/kg/h) of pyruvate successfully increased oxygen metabolism in post 10-min CA rats. Plasma ATP levels increased significantly from 67 ± 11 nM before CA to 227 ± 103 nM 2 h after the resuscitation; however, pyruvate administration did not affect post-CA ATP levels. Notably, pyruvate improved post-CA cardiac contraction and acidemia (low pH). We also found that pyruvate increased systemic CO2 production post-CA. These data support that pyruvate has therapeutic potential for improving CA outcomes by enhancing oxygen and energy metabolism in the brain and heart and attenuating intracellular hydrogen ion disorders, but does not exacerbate the death-signaling of eATP in the blood.

Effects of mild hypercapnia on myocardial injury after out-of-hospital cardiac arrest. A sub-study of the TAME trial

PURPOSE

Mild hypercapnia did not improve neurological outcomes for resuscitated out-of-hospital cardiac arrest (OHCA) patients in the Targeted Therapeutic Mild Hypercapnia After Resuscitated Cardiac Arrest (TAME) trial. However, the effects of hypercapnic acidosis on myocardial injury in patients with cardiac arrest is unexplored. We investigated whether mild hypercapnia compared to normocapnia, following emergency coronary intervention, increased myocardial injury in comatose OHCA-patients with AMI.

METHODS

Single-centre, prospective, pre-planned sub-study of the TAME trial. Patients were randomised to targeted mild hypercapnia (PaCO2 = 6.7-7.3 kPa) or normocapnia (PaCO2 = 4.7-6.0 kPa) for 24 h. Myocardial injury was assessed with high-sensitive cardiac troponin T (hs-cTnT) measured at baseline, 24, 48 and 72 h. Haemodynamics were assessed with right heart catheterisation and blood-gas analyses every 4th hour for 48 h.

RESULTS

We included 125 OHCA-patients. 57 (46%) had an AMI, with 31 and 26 patients randomised to hypercapnia and normocapnia, respectively. Median peak hs-cTnT in AMI-patients was 58% lower in the hypercapnia-group: 2136 (IQR: 861-4462) versus 5165 ng/L (IQR: 2773-7519), p = 0.007. Lower average area under the hs-cTnT curve was observed in the hypercapnia-group: 2353 (95% CI 1388-3319) versus 4953 ng/L (95% CI 3566-6341), P-group = 0.002. Hypercapnia was associated with increased cardiac power output (CPO) and lower lactate levels in patients with AMI (P-group < 0.05). hs-cTnT, lactate and CPO were not significantly different between intervention groups in OHCA-patients without AMI (p > 0.05).

CONCLUSIONS

Mild hypercapnia was not associated with increased myocardial injury in resuscitated OHCA-patients. In AMI-patients, mild hypercapnia was associated with lower hs-cTnT and lactate, and improved cardiac performance.

TRIAL REGISTRATION NUMBER

NCT03114033.

Circulating glycocalyx shedding products as biomarkers for evaluating prognosis of patients with out-of-hospital cardiac arrest after return of spontaneous circulation

The endothelial glycocalyx is damaged in postcardiac arrest syndrome (PCAS), but the prognostic value is unknown. We aimed to observe the expression and prognostic value of glycocalyx shedding products, including syndecan-1 (SDC-1), hyaluronan (HA), and heparan sulfate (HS) in PCAS. Data on clinical and 28-day outcomes of seventy-one consecutive patients with out-of-hospital cardiac arrest (OHCA) after the return of spontaneous circulation (ROSC) were collected. SDC-1, HA, and HS were measured on days 0, 1, and 3 after ROSC. Thirty healthy individuals were controls. Glycocalyx shedding was observed in human umbilical vein endothelial cells (HUVECs) stimulated during hypoxia and reoxygenation in vitro. Within 4 h of ROSC, SDC-1 and HA levels, significantly increased. In the 28-day non-survivors, HA levels showed a gradual upward trend, SDC-1 remained at a high level, and HS levels first increased, then decreased. Kaplan-Meier curves and binary logistic regression analysis showed the prognostic value of SDC-1 levels on days 0, 1, and 3, HA levels on days 1 and 3, and HS levels on day 1. Only HS levels on day 1 showed a prognostic value for 28-day neurological outcomes. SDC-1 and HA levels were positively correlated with the no-flow time. In vitro, HUVECs showed shedding of SDC-1 and HS during a prolonged duration of hypoxia. After ROSC, SDC-1, HA, and HS levels may predict the 28-day survival after PCAS, and HS levels are associated with functional outcomes.

Neuroprotective Effects of Inhaled Xenon Gas on Brain Structural Gray Matter Changes After Out-of-Hospital Cardiac Arrest Evaluated by Morphometric Analysis: A Substudy of the Randomized Xe-Hypotheca Trial

BACKGROUND

We have earlier reported that inhaled xenon combined with hypothermia attenuates brain white matter injury in comatose survivors of out-of-hospital cardiac arrest (OHCA). A predefined secondary objective was to assess the effect of inhaled xenon on the structural changes in gray matter in comatose survivors after OHCA.

METHODS

Patients were randomly assigned to receive either inhaled xenon combined with target temperature management (33 °C) for 24 h (n = 55, xenon group) or target temperature management alone (n = 55, control group). A change of brain gray matter volume was assessed with a voxel-based morphometry evaluation of high-resolution structural brain magnetic resonance imaging (MRI) data with Statistical Parametric Mapping. Patients were scheduled to undergo the first MRI between 36 and 52 h and a second MRI 10 days after OHCA.

RESULTS

Of the 110 randomly assigned patients in the Xe-Hypotheca trial, 66 patients completed both MRI scans. After all imaging-based exclusions, 21 patients in the control group and 24 patients in the xenon group had both scan 1 and scan 2 available for analyses with scans that fulfilled the quality criteria. Compared with the xenon group, the control group had a significant decrease in brain gray matter volume in several clusters in the second scan compared with the first. In a between-group analysis, significant reductions were found in the right amygdala/entorhinal cortex (p = 0.025), left amygdala (p = 0.043), left middle temporal gyrus (p = 0.042), left inferior temporal gyrus (p = 0.008), left parahippocampal gyrus (p = 0.042), left temporal pole (p = 0.042), and left cerebellar cortex (p = 0.005). In the remaining gray matter areas, there were no significant changes between the groups.

CONCLUSIONS

In comatose survivors of OHCA, inhaled xenon combined with targeted temperature management preserved gray matter better than hypothermia alone.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT00879892.

Exploratory Feasibility Study of Cerebral Cooling by Transpulmonary Cooling During Cardiac Arrest in a Swine Cardiac Arrest Model

Studies on targeted temperature management for postcardiac arrest syndrome have shown no difference in outcomes between normothermia and hypothermia in patients with postcardiac arrest brain injury. Therefore, further development of therapeutic methods for temperature control in cardiac arrest patients is desirable. Although animal studies have shown that inducing hypothermia during cardiac arrest improves outcomes, no clinically effective method has yet been reported. We investigated whether intra-arrest lung cooling (IALC) effectively lowers brain temperature. A device capable of cooling oxygen was developed. The pigs were subjected to cardiac arrest using the device, ventilated, cooled during cardiopulmonary resuscitation, and resuscitated for 1 hour, with changes in brain temperature closely monitored. A device capable of cooling oxygen to -30°C was used to cool the lungs during cardiac arrest. Through this approach, IALC successfully reduced the brain temperature. Optimal cooling efficiency was observed when chest compressions and ventilation were synchronized at a ratio of 5:1, resulting in an approximate brain temperature reduction of 1.5°C/h. Our successful development of an oxygen-cooling device underscores the potential for lowering brain temperature through IALC using inhaled oxygen cooling.

Investigation of fingolimod-induced lymphocyte sequestration on inflammatory response and neurological damages after cardiac arrest

BACKGROUND

A sepsis-like syndrome is known to occur after cardiac arrest, leading to cerebral infiltration by white blood cells (WBC). We hypothesized that pharmacological sequestration of WBC, and more specifically lymphocytes within lymphoid tissues, could reduce the cerebral infiltration by these inflammatory cells and subsequent acute brain injury in a porcine model of cardiac arrest. Lymphocyte sequestration was induced by the sphingosine-1 phosphate receptors agonist fingolimod.

METHODS

In a first set of experiments, anesthetized pigs underwent a sham instrumentation with no cardiac arrest (n = 4). They received an administration of fingolimod (1 mg/kg, i.v.) in order to confirm its effect on WBC. In a second set of experiments, animals randomly received fingolimod or saline two hours prior to an episode of ventricular fibrillation (14 min) with subsequent resuscitation (n = 6 in each group). Neurological injury was assessed 24 h after resuscitation.

RESULTS

In the first set of experiments, WBC and blood lymphocyte counts were significantly reduced by - 61 ± 10% and - 75 ± 6% two hours after fingolimod administration. In the second set of experiments, blood lymphocyte counts, but not WBC, were also significantly reduced after cardiac arrest in Fingolimod vs Control group. However, most cytokine blood levels were not different among groups, including Interleukin (IL)-1ra, IL-8 or IL-18 blood levels. A difference was only observed for IL-6, which decreased in Fingolimod vs Control (e.g., 5.6 ± 4.8 vs 59.4 ± 20.6 pg/ml at 2 h after cardiac arrest, respectively; p = 0.126). Neurofilament light chain (NFL) blood levels were not different among groups (57 ± 25 vs 84 ± 41 pg/ml in Fingolimod vs Control at 6 h after resuscitation, respectively). After awakening, 3 and 2 animals were prematurely euthanized for ethical reasons due to recurrent seizures in Fingolimod and Control groups, respectively. At Day 1, neurological dysfunction score was not different between groups (87 ± 7 vs 87 ± 5% in Fingolimod vs Control, respectively). Conversely, a decrease in the number of CD3 + cells was observed in the brain of surviving animals in Fingolimod vs Control group (3.10 ± 0.50 vs 7.53 ± 0.57 CD3 + cells/field, respectively; p = 0.0286).

CONCLUSION

Fingolimod-induced WBC sequestration, and more specifically lymphocytes sequestration, did not improve clinical neurological dysfunction following cardiac arrest although it reduced cerebral infiltration by lymphocytes.

Multi-omics Study of Hypoxic-Ischemic Brain Injury After Cardiopulmonary Resuscitation in Swine

BACKGROUND

Hypoxic-ischemic brain injury is a common cause of mortality after cardiac arrest (CA) and cardiopulmonary resuscitation; however, the specific underlying mechanisms are unclear. This study aimed to explore postresuscitation changes based on multi-omics profiling.

METHODS

A CA swine model was established, and the neurological function was assessed at 24 h after resuscitation, followed by euthanizing animals. Their fecal, blood, and hippocampus samples were collected to analyze gut microbiota, metabolomics, and transcriptomics.

RESULTS

The 16S ribosomal DNA sequencing showed that the microbiota composition and diversity changed after resuscitation, in which the abundance of Akkermansia and Muribaculaceae_unclassified increased while the abundance of Bifidobacterium and Romboutsia decreased. A relationship was observed between CA-related microbes and metabolites via integrated analysis of gut microbiota and metabolomics, in which Escherichia-Shigella was positively correlated with glycine. Combined metabolomics and transcriptomics analysis showed that glycine was positively correlated with genes involved in apoptosis, interleukin-17, mitogen-activated protein kinases, nuclear factor kappa B, and Toll-like receptor signal pathways.

CONCLUSIONS

Our results provided novel insight into the mechanism of hypoxic-ischemic brain injury after resuscitation, which is envisaged to help identify potential diagnostic and therapeutic markers.

Emergent Management of Hypoxic-Ischemic Brain Injury

OBJECTIVE

This article outlines interventions used to improve outcomes for patients with hypoxic-ischemic brain injury after cardiac arrest.

LATEST DEVELOPMENTS

Emergent management of patients after cardiac arrest requires prevention and treatment of primary and secondary brain injury. Primary brain injury is minimized by excellent initial resuscitative efforts. Secondary brain injury prevention requires the detection and correction of many pathophysiologic processes that may develop in the hours to days after the initial arrest. Key physiologic parameters important to secondary brain injury prevention include optimization of mean arterial pressure, cerebral perfusion, oxygenation and ventilation, intracranial pressure, temperature, and cortical hyperexcitability. This article outlines recent data regarding the treatment and prevention of secondary brain injury. Different patients likely benefit from different treatment strategies, so an individualized approach to treatment and prevention of secondary brain injury is advisable. Clinicians must use multimodal sources of data to prognosticate outcomes after cardiac arrest while recognizing that all prognostic tools have shortcomings.

ESSENTIAL POINTS

Neurologists should be involved in the postarrest care of patients with hypoxic-ischemic brain injury to improve their outcomes. Postarrest care requires nuanced and patient-centered approaches to the prevention and treatment of primary and secondary brain injury and neuroprognostication.

Cerebral perfusion and metabolism with mild hypercapnia vs. normocapnia in a porcine post cardiac arrest model with and without targeted temperature management

Aim

To determine whether targeting mild hypercapnia (PaCO2 7 kPa) would yield improved cerebral blood flow and metabolism compared to normocapnia (PaCO2 5 kPa) with and without targeted temperature management to 33 °C (TTM33) in a porcine post-cardiac arrest model.

Methods

39 pigs were resuscitated after 10 minutes of cardiac arrest using cardiopulmonary bypass and randomised to TTM33 or no-TTM, and hypercapnia or normocapnia. TTM33 was managed with intravasal cooling. Animals were stabilized for 30 minutes followed by a two-hour intervention period. Hemodynamic parameters were measured continuously, and neuromonitoring included intracranial pressure (ICP), pressure reactivity index, cerebral blood flow, brain-tissue pCO2 and microdialysis. Measurements are reported as proportion of baseline, and areas under the curve during the 120 min intervention period were compared.

Results

Hypercapnia increased cerebral flow in both TTM33 and no-TTM groups, but also increased ICP (199% vs. 183% of baseline, p = 0.018) and reduced cerebral perfusion pressure (70% vs. 84% of baseline, p < 0.001) in no-TTM animals. Cerebral lactate (196% vs. 297% of baseline, p < 0.001), pyruvate (118% vs. 152% of baseline, p < 0.001), glycerol and lactate/pyruvate ratios were lower with hypercapnia in the TTM33 group, but only pyruvate (133% vs. 150% of baseline, p = 0.002) was lower with hypercapnia among no-TTM animals.

Conclusion

In this porcine post-arrest model, hypercapnia led to increased cerebral flow both with and without hypothermia, but also increased ICP and reduced cerebral perfusion pressure in no-TTM animals. The effects of hypercapnia were different with and without TTM.(Institutional protocol number: FOTS, id 14931).

Impact of Blood Pressure Targets in Patients With Heart Failure Undergoing Postresuscitation Care: A Subgroup Analysis From a Randomized Controlled Trial

BACKGROUND

To assess the effect of targeting higher or lower blood pressure during postresucitation intensive care among comatose patients with out-of-hospital cardiac arrest with a history of heart failure.

METHODS

The BOX trial (Blood Pressure and Oxygenation Targets After Out-of-Hospital Cardiac Arrest) was a randomized, controlled, double-blinded, multicenter study comparing titration of vasopressors toward a mean arterial pressure (MAP) of 63 versus 77 mm Hg during postresuscitation intensive care. Patients with a history of heart failure were included in this substudy. Pulmonary artery catheters were inserted shortly after admission. History of heart failure was assessed through chart review of all included patients. The primary outcome was cardiac index during the first 72 hours. Secondary outcomes were left ventricular ejection fraction, heart rate, stroke volume, renal replacement therapy and all-cause mortality at 365 days.

RESULTS

A total of 134 patients (17% of the BOX cohort) had a history of heart failure (patients with left ventricular ejection fraction, ≤40%: 103 [77%]) of which 71 (53%) were allocated to a MAP of 77 mm Hg. Cardiac index at intensive care unit arrival was 1.77±0.11 L/min·m-2 in the MAP63-group and 1.78±0.17 L/min·m-2 in the MAP77, P=0.92. During the next 72 hours, the mean difference was 0.15 (95% CI, -0.04 to 0.35) L/min·m-2; Pgroup=0.22. Left ventricular ejection fraction and stroke volume was similar between the groups. Patients allocated to MAP77 had significantly elevated heart rate (mean difference 6 [1-12] beats/min, Pgroup=0.03). Vasopressor usage was also significantly increased (P=0.006). At 365 days, 69 (51%) of the patients had died. The adjusted hazard ratio for 365 day mortality was 1.38 (0.84-2.27), P=0.20 and adjusted odds ratio for renal replacement therapy was 2.73 (0.84-8.89; P=0.09).

CONCLUSIONS

In resuscitated patients with out-of-hospital cardiac arrest with a history of heart failure, allocation to a higher blood pressure target resulted in significantly increased heart rate in the higher blood pressure-target group. However, no certain differences was found for cardiac index, left ventricular ejection fraction or stroke volume.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03141099.

Acute kidney injury after out-of-hospital cardiac arrest

BACKGROUND

Acute kidney injury (AKI) is a significant risk factor associated with reduced survival following out-of-hospital cardiac arrest (OHCA). Whether the severity of AKI simply serves as a surrogate measure of worse peri-arrest conditions, or represents an additional risk to long-term survival remains unclear.

METHODS

This is a sub-study derived from a randomized trial in which 789 comatose adult OHCA patients with presumed cardiac cause and sustained return of spontaneous circulation (ROSC) were enrolled. Patients without prior dialysis dependent kidney disease and surviving at least 48 h were included (N = 759). AKI was defined by the kidney disease: improving global outcome (KDIGO) classification, and patients were divided into groups based on the development of AKI and the need for continuous kidney replacement therapy (CKRT), thus establishing three groups of patients-No AKI, AKI no CKRT, and AKI CKRT. Primary outcome was overall survival within 365 days after OHCA according to AKI group. Adjusted Cox proportional hazard models were used to assess overall survival within 365 days according to the three groups.

RESULTS

In the whole population, median age was 64 (54-73) years, 80% male, 90% of patients presented with shockable rhythm, and time to ROSC was median 18 (12-26) min. A total of 254 (33.5%) patients developed AKI according to the KDIGO definition, with 77 requiring CKRT and 177 without need for CKRT. AKI CKRT patients had longer time-to-ROSC and worse metabolic derangement at hospital admission. Overall survival within 365 days from OHCA decreased with the severity of kidney injury. Adjusted Cox regression analysis found that AKI, both with and without CKRT, was significantly associated with reduced overall survival up until 365 days, with comparable hazard ratios relative to no AKI (HR 1.75, 95% CI 1.13-2.70 vs. HR 1.76, 95% CI 1.30-2.39).

CONCLUSIONS

In comatose patients who had been resuscitated after OHCA, patients developing AKI, with or without initiation of CKRT, had a worse 1-year overall survival compared to non-AKI patients. This association remains statistically significant after adjusting for other peri-arrest risk factors.

TRIAL REGISTRATION

The BOX trial is registered at ClinicalTrials.gov: NCT03141099.

Ketone Bodies after Cardiac Arrest: A Narrative Review and the Rationale for Use

Cardiac arrest survivors suffer the repercussions of anoxic brain injury, a critical factor influencing long-term prognosis. This injury is characterised by profound and enduring metabolic impairment. Ketone bodies, an alternative energetic resource in physiological states such as exercise, fasting, and extended starvation, are avidly taken up and used by the brain. Both the ketogenic diet and exogenous ketone supplementation have been associated with neuroprotective effects across a spectrum of conditions. These include refractory epilepsy, neurodegenerative disorders, cognitive impairment, focal cerebral ischemia, and traumatic brain injuries. Beyond this, ketone bodies possess a plethora of attributes that appear to be particularly favourable after cardiac arrest. These encompass anti-inflammatory effects, the attenuation of oxidative stress, the improvement of mitochondrial function, a glucose-sparing effect, and the enhancement of cardiac function. The aim of this manuscript is to appraise pertinent scientific literature on the topic through a narrative review. We aim to encapsulate the existing evidence and underscore the potential therapeutic value of ketone bodies in the context of cardiac arrest to provide a rationale for their use in forthcoming translational research efforts.

Acute Lung Injury after Cardiopulmonary Resuscitation: A Narrative Review

Although cardiopulmonary resuscitation (CPR) includes lifesaving maneuvers, it might be associated with a wide spectrum of iatrogenic injuries. Among these, acute lung injury (ALI) is frequent and yields significant challenges to post-cardiac arrest recovery. Understanding the relationship between CPR and ALI is determinant for refining resuscitation techniques and improving patient outcomes. This review aims to analyze the existing literature on ALI following CPR, emphasizing prevalence, clinical implications, and contributing factors. The review seeks to elucidate the pathogenesis of ALI in the context of CPR, assess the efficacy of CPR techniques and ventilation strategies, and explore their impact on post-cardiac arrest outcomes. CPR-related injuries, ranging from skeletal fractures to severe internal organ damage, underscore the complexity of managing post-cardiac arrest patients. Chest compression, particularly when prolonged and vigorous, i.e., mechanical compression, appears to be a crucial factor contributing to ALI, with the concept of cardiopulmonary resuscitation-associated lung edema (CRALE) gaining prominence. Ventilation strategies during CPR and post-cardiac arrest syndrome also play pivotal roles in ALI development. The recognition of CPR-related lung injuries, especially CRALE and ALI, highlights the need for research on optimizing CPR techniques and tailoring ventilation strategies during and after resuscitation.

The agreement between jugular bulb and cerebrospinal fluid lactate levels in patients with out-of-hospital cardiac arrest

We investigated the agreement between the jugular bulb (JB) and cerebrospinal fluid (CSF) lactate levels. The study was conducted from July 2021 to June 2023 as a prospective observational cohort study at a single center. The right jugular vein was accessed, and the placement of JB catheter tip was confirmed using lateral cervical spine X-ray. A lumbar catheter was inserted between the 3rd and 4th lumbar spine of the patient. Lactate levels were measured immediately, 24 h, 48 h, and 72 h after ROSC. In patients with a good neurological prognosis, kappa between JB and CSF lactate levels measured immediately, at 24 h, 48 h, and 72 h after ROSC were 0.08, 0.36, 0.14, - 0.05 (p = 0.65, 0.06, 0.48, and 0.75, respectively). However, in patients with a poor neurological prognosis, kappa between JB and CSF lactate levels measured immediately, at 24 h, 48 h, and 72 h after ROSC were 0.38, 0.21, 0.22, 0.12 (p = 0.001, 0.04, 0.04, and 0.27, respectively). This study demonstrated that JB lactate levels exhibited significant agreement with arterial lactate levels, compared to CSF lactate levels. Therefore, this should be considered when using JB lactate to monitor cerebral metabolism.

Fluid balance during acute phase extracorporeal cardiopulmonary resuscitation and outcomes in OHCA patients: a retrospective multicenter cohort study

OBJECTIVE

The association between fluid balance and outcomes in patients who underwent out-of-hospital cardiac arrest (OHCA) and received extracorporeal cardiopulmonary resuscitation (ECPR) remains unknown. We aimed to examine the above relationship during the first 24 h following intensive care unit (ICU) admission.

METHODS

We performed a secondary analysis of the SAVE-J II study, a retrospective multicenter study involving OHCA patients aged ≥ 18 years treated with ECPR between 2013 and 2018 and who received fluid therapy following ICU admission. Fluid balance was calculated based on intravenous fluid administration, blood transfusion, and urine output. The primary outcome was in-hospital mortality. The secondary outcomes included unfavorable outcome (cerebral performance category scores of 3-5 at discharge), acute kidney injury (AKI), and need for renal replacement therapy (RRT).

RESULTS

Overall, 959 patients met our inclusion criteria. In-hospital mortality was 63.6%, and the proportion of unfavorable outcome at discharge was 82.0%. The median fluid balance in the first 24 h following ICU admission was 3673 mL. Multivariable analysis revealed that fluid balance was significantly associated with in-hospital mortality (odds ratio (OR), 1.04; 95% confidence interval (CI), 1.02-1.06; p < 0.001), unfavorable outcome (OR, 1.03; 95% CI, 1.01-1.06; p = 0.005), AKI (OR, 1.04; 95% CI, 1.02-1.05; p < 0.001), and RRT (OR, 1.05; 95% CI, 1.03-1.07; p < 0.001).

CONCLUSIONS

Excessive positive fluid balance in the first day following ICU admission was associated with in-hospital mortality, unfavorable outcome, AKI, and RRT in ECPR patients. Further investigation is warranted.

An Autopsy Case of Reversible Cerebral Vasoconstriction Syndrome After a Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination

A 73-year-old man with chronic obstructive pulmonary disease received the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine. The following day, the patient developed a headache, followed by a tonic-clonic seizure and decreased consciousness. Magnetic resonance imaging of the head revealed no signs of stroke but multiple vasoconstrictions. Despite antiepileptic therapy, the seizure persisted, and the patient died 40 hours after vaccination. An autopsy revealed multiple brain ischemia without any vascular lesions, suggesting reversible cerebral vasoconstriction syndrome (RCVS). In this case, RCVS was diagnosed radiographically and pathologically. Our case suggests that RCVS could be a cause of headache and epilepsy following the SARS-CoV-2 mRNA vaccination.

[Post Resuscitation Care]

After successful resuscitation, further treatment has a decisive influence regarding patient outcome. Not only overall survival, but also the neurological outcome that is crucial for patients' quality of life can be positively influenced by optimized post-cardiac arrest treatment. The management of various consequences of post-cardiac arrest syndrome is discussed in the current version of the ERC-guidelines in the chapter "post resuscitation care". A step-by-step approach based on an algorithm provides the necessary structure. The immediate treatment and stabilization of patients after ROSC is followed by the diagnosis of the triggering pathology in order to initiate adequate therapy. During the subsequent intensive care treatment, the focus is on optimizing neurological recovery.

Canagliflozin Pretreatment Attenuates Myocardial Dysfunction and Improves Postcardiac Arrest Outcomes After Cardiac Arrest and Cardiopulmonary Resuscitation in Mice

OBJECTIVE

The SGLT2 inhibitor, canagliflozin, not only reduces glycemia in patients with type 2 diabetes but also exerts cardioprotective effects in individuals without diabetes. However, its potential beneficial effects in cardiac arrest have not been characterized. The purpose of this study was to examine the protective effect of canagliflozin pretreatment on postresuscitation-induced cardiac dysfunction in vivo.

METHODS

Male C57/BL6 mice were randomized to vehicle (sham and control) or canagliflozin treatment groups. All mice except for the sham-operated mice were subjected to potassium chloride-induced cardiac arrest followed by chest compressions and intravenous epinephrine for resuscitation. Canagliflozin therapy efficacies were evaluated by electrocardiogram, echocardiography, histological analysis, inflammatory response, serum markers of myocardial injury, protein phosphorylation analysis, and immunohistological assessment.

RESULTS

Canagliflozin-pretreated mice exhibited a higher survival rate (P < 0.05), a shorter return of spontaneous circulation (ROSC) time (P < 0.01) and a higher neurological score (P < 0.01 or P < 0.001) than control mice after resuscitation. Canagliflozin was effective at improving cardiac arrest and resuscitation-associated cardiac dysfunction, indicated by increased left ventricular ejection fraction and fractional shortening (P < 0.001). Canagliflozin reduced serum levels of LDH, CK-MB and α-HBDH, ameliorated systemic inflammatory response, and diminished the incidence of early resuscitation-induced arrhythmia. Notably, canagliflozin promoted phosphorylation of cardiac STAT-3 postresuscitation. Furthermore, pharmacological inhibition of STAT-3 by Ag490 blunted STAT-3 phosphorylation and abolished the cardioprotective actions of canagliflozin.

CONCLUSIONS

Canagliflozin offered a strong cardioprotective effect against cardiac arrest and resuscitation-induced cardiac dysfunction. This canagliflozin-induced cardioprotection is mediated by the STAT-3-dependent cell-survival signaling pathway.

Cardiac arrest, stony heart, and cardiopulmonary resuscitation: An updated revisit

The post-resuscitation period is recognized as the main predictor of cardiopulmonary resuscitation (CPR) outcomes. The first description of post-resuscitation syndrome and stony heart was published over 50 years ago. Major manifestations may include but are not limited to, persistent precipitating pathology, systemic ischemia/reperfusion response, post-cardiac arrest brain injury, and finally, post-cardiac arrest myocardial dysfunction (PAMD) after successful resuscitation. Why do some patients initially survive successful resuscitation, and others do not? Also, why does the myocardium response vary after resuscitation? These questions have kept scientists busy for several decades since the first successful resuscitation was described. By modifying the conventional modalities of resuscitation together with new promising agents, rescuers will be able to salvage the jeopardized post-resuscitation myocardium and prevent its progression to a dismal, stony heart. Community awareness and staff education are crucial for shortening the resuscitation time and improving short- and long-term outcomes. Awareness of these components before and early after the restoration of circulation will enhance the resuscitation outcomes. This review extensively addresses the underlying pathophysiology, management, and outcomes of post-resuscitation syndrome. The pattern, management, and outcome of PAMD and post-cardiac arrest shock are different based on many factors, including in-hospital cardiac arrest vs out-of-hospital cardiac arrest (OHCA), witnessed vs unwitnessed cardiac arrest, the underlying cause of arrest, the duration, and protocol used for CPR. Although restoring spontaneous circulation is a vital sign, it should not be the end of the game or lone primary outcome; it calls for better understanding and aggressive multi-disciplinary interventions and care. The development of stony heart post-CPR and OHCA remain the main challenges in emergency and critical care medicine.

Immune cell expression patterns of CD39/CD73 ectonucleotidases in rodent models of cardiac arrest and resuscitation

Background

Cardiac arrest (CA) is a significant public health concern. There is the high imminent mortality and survival in those who are resuscitated is substantively compromised by the post-CA syndrome (PCAS), characterized by multiorgan ischemia-reperfusion injury (IRI). The inflammatory response in PCAS is complex and involves various immune cell types, including lymphocytes and myeloid cells that have been shown to exacerbate organ IRI, such as myocardial infarction. Purinergic signaling, as regulated by CD39 and CD73, has emerged as centrally important in the context of organ-specific IRI. Hence, comprehensive understanding of such purinergic responses may be likewise imperative for improving outcomes in PCAS.

Methods

We have investigated alterations of immune cell populations after CA by utilizing rodent models of PCAS. Blood and spleen were collected after CA and resuscitation and underwent flow cytometry analysis to evaluate shifts in CD3+CD4+ helper T cells, CD3+CD8a+ cytotoxic T cells, and CD4/CD8a ratios. We then examined the expression of CD39 and CD73 across diverse cell types, including myeloid cells, T lymphocytes, and B lymphocytes.

Results

In both rat and mouse models, there were significant increases in the frequency of CD3+CD4+ T lymphocytes in PCAS (rat, P < 0.01; mouse, P < 0.001), with consequently elevated CD4/CD8a ratios in whole blood (both, P < 0.001). Moreover, CD39 and CD73 expression on blood leukocytes were markedly increased (rat, P < 0.05; mouse, P < 0.01 at 24h). Further analysis in the experimental mouse model revealed that CD11b+ myeloid cells, with significant increase in their population (P < 0.01), had high level of CD39 (88.80 ± 2.05 %) and increased expression of CD73 (P < 0.05). CD19+ B lymphocytes showed slight increases of CD39 (P < 0.05 at 2h) and CD73 (P < 0.05 at 2h), while, CD3+ T lymphocytes had decreased levels of them. These findings suggested a distinct patterns of expression of CD39 and CD73 in these specific immune cell populations after CA.

Conclusions

These data have provided comprehensive insights into the immune response after CA, highlighting high-level expressions of CD39 and CD73 in myeloid cells.

Lower versus higher oxygen targets after resuscitation from out-of-hospital cardiac arrest: A systematic review and meta-analysis of randomized controlled trials

PURPOSE

To update the existing evidence and gain further insight into effects of lower versus higher oxygen targets on the outcomes in patients resuscitated from out-of-hospital cardiac arrest (OHCA).

METHODS

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing lower versus higher oxygen targets on the outcomes among adults resuscitated from OHCA. The primary outcome was short-term survival (in hospital or within 30 days). Subgroup analyses were performed according to timing of study interventions.

RESULTS

Seven RCTs with 1454 patients were finally included. The short-term survival did not differ between the two groups with a relative risk (RR) of 0.98 (95% CI, 0.86 to 1.11). There were no significant differences in survival at longest follow-up (RR, 1.01; 95% CI, 0.91 to 1.14), favorable neurological outcome (RR, 1.00; 95% CI, 0.91 to 1.11), length of intensive care unit stay (mean difference, -4.94 h; 95% CI, -14.83 to 4.96 h), or risk of re-arrest (RR, 0.68; 95% CI, 0.21 to 2.19). The quality of evidence ranged from moderate to very low.

CONCLUSION

Current evidence suggests that targeting a lower or higher oxygen therapy in patients after resuscitation from OHCA results in similar short-term survival and other clinical outcomes.

Recovery and Survival of Patients After Out-of-Hospital Cardiac Arrest: A Literature Review Showcasing the Big Picture of Intensive Care Unit-Related Factors

As an important public health issue, out-of-hospital cardiac arrest (OHCA) requires several stages of high quality medical care, both on-field and after hospital admission. Post-cardiac arrest shock can lead to severe neurological injury, resulting in poor recovery outcome and increased risk of death. These characteristics make this condition one of the most important issues to deal with in post-OHCA patients hospitalized in intensive care units (ICUs). Also, the majority of initial post-resuscitation survivors have underlying coronary diseases making revascularization procedure another crucial step in early management of these patients. Besides keeping myocardial blood flow at a satisfactory level, other tissues must not be neglected as well, and maintaining mean arterial pressure within optimal range is also preferable. All these procedures can be simplified to a certain level along with using targeted temperature management methods in order to decrease metabolic demands in ICU-hospitalized post-OHCA patients. Additionally, withdrawal of life-sustaining therapy as a controversial ethical topic is under constant re-evaluation due to its possible influence on overall mortality rates in patients initially surviving OHCA. Focusing on all of these important points in process of managing ICU patients is an imperative towards better survival and complete recovery rates.

Addition of Vitamin C Does Not Decrease Neuron-Specific Enolase Levels in Adult Survivors of Cardiac Arrest-Results of a Randomized Trial

Background and Objectives: Survival with favorable neurologic outcomes after out-of-hospital cardiac arrest (OHCA) remains elusive. Post-cardiac arrest syndrome (PCAS) involves myocardial and neurological injury, ischemia-reperfusion response, and underlying pathology. Neurologic injury is a crucial determinant of survival and functional outcomes, with damage caused by free radicals among the responsible mechanisms. This study explores the feasibility of adding intravenous vitamin C to the treatment of OHCA survivors, aiming to mitigate PCAS. Vitamin C, a nutrient with antioxidative and free radical-scavenging properties, is often depleted in critically ill patients. Materials and Methods: This randomized, double-blinded trial was conducted at a tertiary-level university hospital with adult OHCA survivors. Participants received either standard care or the addition of 1.5 g of intravenous vitamin C every 12 h for eight consecutive doses. Neurologic injury was assessed using neuron-specific enolase (NSE) levels, with additional clinical and laboratory outcomes, such as enhanced neuroprognostication factors, inflammatory markers, and cardiac parameters. Results: NSE levels were non-significantly higher in patients who received vitamin C compared to the placebo group (55.05 µg/L [95% confidence interval (CI) 26.7-124.0] vs. 39.4 µg/L [95% CI 22.6-61.9], p > 0.05). Similarly, a non-significantly greater proportion of patients in the vitamin C group developed myoclonus in the first 72 h. We also observed a non-significantly shorter duration of mechanical ventilation, fewer arrhythmias, and reduced length of stay in the intensive care unit in the group of patients who received vitamin C (p = 0.031). However, caution is warranted in interpretation of our results due to the small number of participants. Conclusions: Our findings suggest that intravenous vitamin C should not be used outside of clinical trials for OHCA survivors. Due to the small sample size and conflicting results, further research is needed to determine the potential role of vitamin C in post-cardiac arrest care.

Treatment effects of blood pressure targets and hemodynamics according to initial blood lactate levels in comatose out-of-hospital cardiac arrest patients - A sub study of the BOX trial

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) survivors remaining comatose are often circulatory unstable with high mortality in the first days following resuscitation. Elevated lactate will reflect the severity and duration of hypoperfusion in cardiac arrest. Further, the severity of hypoperfusion could modify the effect on survival of different mean arterial blood pressure (MAP) targets.

METHODS

In this sub-study of the BOX trial, adult successfully resuscitated comatose OHCA patients (n = 789) with a presumed cardiac cause were randomized to a MAP target of 63 mmHg vs. 77 mmHg. Patients were arbitrarily grouped in low-lactate: <25% of sample, medium-lactate: 25%-75%, and high >75 percentile according to blood lactate levels at hospital arrival as a surrogate of the severity of hypoperfusion. Invasive hemodynamic evaluations were performed using an arterial catheter and pulmonary artery catheter (PAC), and data from admission to 48 hours (h) were recorded. Logistic regression analysis evaluated whether lactate levels (as continuous and categorical) modify the effect of MAP targets on mortality at 365 days.

RESULTS

The three lactate groups had initial lactate levels of low-lactate: <2.9 mmol/L, medium-lactate: 2.9-7.9 mmol/L, and high-lactate > 7.9 mmol/L. All patients were randomized to a 63 mmHg or 77 mmHg MAP target. The proportion of patients in the high-MAP target group was 100/201 (50%), 178/388 (46%), and 114/197 (58%) for low, medium, and high-lactate groups respectively. At admission, the high-lactate groups had a lower MAP compared to the medium-lactate (2.6 mmHg (95% CI: 0.1-5.0 mmHg, p = 0.02), and the low-lactate group, (3.6 mmHg (95% CI: 0.8-6.5 mmHg, p < 0.01). Accordingly, the vasoactive inotropic score was 79% (95%CI: 42%-124%%) higher with increasing initial lactate level (High-lactate vs. low-lactate) with the largest difference at 6 hours (110.6% (95%CI: 54.4%-187.2%) higher in high-lactate patients). No difference in the cardiac index or systemic vascular resistance was observed between lactate groups. The initial lactate level (continuous) modified the effect of the two MAP targets (p = 0.04). In the highest lactate group, the mortality was 100/197 (51%), and with an odds ratio (OR): 1.7 (95%CI: 0.9-3.0) if randomized to MAP 77 mmHg compared to MAP 63 mmHg. In the lowest lactate group, the mortality was 35/201(17%) and similar if randomized to a MAP target of 77 mmHg (OR: 1.1 (95% CI: 0.5-2.3)).

CONCLUSION

Comatose OHCA patients with high initial lactate levels required more vasoactive drugs on the first two days of ICU admission to meet the blood pressure target and had a poorer prognosis. No indication that aiming for a higher MAP target is beneficial in patients with an initial high lactate level was found, however, given the post-hoc nature of this study, these results should be considered hypothesis-generating.

Multiorgan failure in patients after out of hospital resuscitation: a retrospective single center study

BACKGROUND

Information on extracerebral system dysfunction is important for assessing the needs of critically ill patients after cardiac arrest.

AIMS

To describe the prevalence of organ dysfunction and patient severity after out of hospital cardiac arrest (OHCA) using scores commonly used in intensive care and the association between these and mortality.

METHODS

Retrospective analysis of observational data collected in real time in a tertiary medical center where care withdrawal is mostly illegal. Adult patients after nontraumatic OHCA with ROSC who survived for more than two hours were included. Primary outcome-prevalence of organ failure, based on common definitions for organ dysfunction, in the 1 days of hospitalization. Secondary outcomes-rates of survival to hospital discharge and survival with a good neurological outcome (CPC 1 or 2), and associations between organ dysfunction SOFA and APACHE-II scores and outcomes. Associations were assessed using fisher's exact test for categorical variables and Mann-Whitney and T test for continuous variables. Multivariable models were also constructed for all measurements showing associations in previous tests. For severity scores compatibility, we used receiver-operating curve (ROC).

RESULTS

Overall 369 patients (median age 75 years, 65% male) were included. Most arrests (64%) were witnessed, bystander CPR was provided in 15%. Median call to arrival time was 4 min. The presenting rhythm was asystole in 48% and VT/VF in 22%. Cardiovascular causes of arrest predominated (48%, n = 178). The median length of hospitalization was 5 days. Overall 28% of the patients (n = 98) survived to hospital discharge, mostly with a good neurological status (18.7%, n = 57). The rates of organ dysfunction were: hemodynamic instability 65% (n = 247), respiratory dysfunction 94% (n = 296), kidney dysfunction 70% (n = 259), hepatic dysfunction 14% (n = 50). The median SOFA score on day 1 was 9 and the median APACHE II score was 34. Modeling was limited by missing data. Neurological dysfunction (i.e. GCS and seizures) and kidney injury were consistently correlated with the outcomes in the multivariable models. Severity of critical illness assessed by above scoring systems correlated with mortality (all ROC curves had an AUC ranging between 0.728 and 0.849).

CONCLUSIONS

Multiorgan failure is common after ROSC (1-4). Therefore, the management of patients after ROSC may require advanced multidisciplinary care. Scores describing the severity of critical illness should be routinely reported in resuscitation research. Our unique setting where withdrawal of care is illegal, allows assessment of extremely ill patients and may assist in defining margins for futility.

Impact of blood pressure targets on central hemodynamics during intensive care after out-of-hospital cardiac arrest

OBJECTIVES

The aim was to investigate the advanced hemodynamic effects of the two MAP-targets during intensive care on systemic hemodynamics in comatose patients after cardiac arrest.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

Primary vasopressor used was per protocol norepinephrine. Hemodynamic monitoring was done with pulmonary artery catheters (PAC) and measurements were made on predefined time points. The primary endpoint of this substudy was the difference in cardiac index within 48 h from a repeated measurements-mixed model. Secondary endpoints included systemic vascular resistance index (SVRI), heart rate, and stroke volume index.

PATIENTS

Comatose survivors after out-of-hospital cardiac arrest.

INTERVENTIONS

The "Blood pressure and oxygenations targets after out-of-hospital cardiac arrest (BOX)"-trial was a randomized, controlled, double-blinded, multicenter-study comparing targeted mean arterial pressure (MAP) of 63 mmHg (MAP63) vs 77 mmHg (MAP77).

MEASUREMENTS AND MAIN RESULTS

Among 789 randomized patients, 730 (93%) patients were included in the hemodynamic substudy. From PAC-insertion (median 1 hours after ICU-admission) and the next 48 hours, the MAP77-group received significantly higher doses of norepinephrine (mean difference 0.09 µg/kg/min, 95% confidence interval (CI) 0.07-0.11, pgroup < 0.0001). Cardiac index was significantly increased (0.20 L/min/m2 (CI 0.12-0.28), pgroup < 0.0001) as was SVRI with an overall difference of (43 dynes m2/s/cm5 (CI 7-79); pgroup = 0.02). Heart rate was increased in the MAP77-group (4 beats/minute; CI 2-6, pgroup < 0.003), but stroke volume index was not (pgroup = 0.10).

CONCLUSIONS

Targeted MAP at 77 mmHg compared to 63 mmHg resulted in a higher dose of norepinephrine, increased cardiac index and SVRI. Heart rate was also increased, but stroke volume index was not affected by a higher blood pressure target.

Blood Pressure and Oxygen Targets on Kidney Injury After Cardiac Arrest

BACKGROUND

Acute kidney injury (AKI) represents a common and serious complication to out-of-hospital cardiac arrest. The importance of post-resuscitation care targets for blood pressure and oxygenation for the development of AKI is unknown.

METHODS

This is a substudy of a randomized 2-by-2 factorial trial, in which 789 comatose adult patients who had out-of-hospital cardiac arrest with presumed cardiac cause and sustained return of spontaneous circulation were randomly assigned to a target mean arterial blood pressure of either 63 or 77 mm Hg. Patients were simultaneously randomly assigned to either a restrictive oxygen target of a partial pressure of arterial oxygen (Pao2) of 9 to 10 kPa or a liberal oxygenation target of a Pao2 of 13 to 14 kPa. The primary outcome for this study was AKI according to KDIGO (Kidney Disease: Improving Global Outcomes) classification in patients surviving at least 48 hours (N=759). Adjusted logistic regression was performed for patients allocated to high blood pressure and liberal oxygen target as reference.

RESULTS

The main population characteristics at admission were: age, 64 (54-73) years; 80% male; 90% shockable rhythm; and time to return of spontaneous circulation, 18 (12-26) minutes. Patients allocated to a low blood pressure and liberal oxygen target had an increased risk of developing AKI compared with patients with high blood pressure and liberal oxygen target (84/193 [44%] versus 56/187 [30%]; adjusted odds ratio, 1.87 [95% CI, 1.21-2.89]). Multinomial logistic regression revealed that the increased risk of AKI was only related to mild-stage AKI (KDIGO stage 1). There was no difference in risk of AKI in the other groups. Plasma creatinine remained high during hospitalization in the low blood pressure and liberal oxygen target group but did not differ between groups at 6- and 12-month follow-up.

CONCLUSIONS

In comatose patients who had been resuscitated after out-of-hospital cardiac arrest, patients allocated to a combination of a low mean arterial blood pressure and a liberal oxygen target had a significantly increased risk of mild-stage AKI. No difference was found in terms of more severe AKI stages or other kidney-related adverse outcomes, and creatinine had normalized at 1 year after discharge.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03141099.

Hyperacute autonomic and cortical function recovery following cardiac arrest resuscitation in a rodent model

OBJECTIVE

There is a complex interaction between nervous and cardiovascular systems, but sparse data exist on brain-heart electrophysiological responses to cardiac arrest resuscitation. Our aim was to investigate dynamic changes in autonomic and cortical function during hyperacute stage post-resuscitation.

METHODS

Ten rats were resuscitated from 7-min cardiac arrest, as indicators of autonomic response, heart rate (HR), and its variability (HRV) were measured. HR was monitored through continuous electrocardiography, while HRV was assessed via spectral analysis, whereby the ratio of low-/high-frequency (LF/HF) power indicates the balance between sympathetic/parasympathetic activities. Cortical response was evaluated by continuous electroencephalography and quantitative analysis. Parameters were quantified at 5-min intervals over the first-hour post-resuscitation. Neurological outcome was assessed by Neurological Deficit Score (NDS, range 0-80, higher = better outcomes) at 4-h post-resuscitation.

RESULTS

A significant increase in HR was noted over 15-30 min post-resuscitation (p < 0.01 vs.15-min, respectively) and correlated with higher NDS (rs = 0.56, p < 0.01). LF/HF ratio over 15-20 min was positively correlated with NDS (rs = 0.75, p < 0.05). Gamma band power surged over 15-30 min post-resuscitation (p < 0.05 vs. 0-15 min, respectively), and gamma band fraction during this period was associated with NDS (rs ≥0.70, p < 0.05, respectively). Significant correlations were identified between increased HR and gamma band power during 15-30 min (rs ≥0.83, p < 0.01, respectively) and between gamma band fraction and LF/HF ratio over 15-20 min post-resuscitation (rs = 0.85, p < 0.01).

INTERPRETATIONS

Hyperacute recovery of autonomic and cortical function is associated with favorable functional outcomes. While this observation needs further validation, it presents a translational opportunity for better autonomic and neurologic monitoring during early periods post-resuscitation to develop novel interventions.

The Effect of Targeted Temperature Management on the Metabolome Following Out-of-Hospital Cardiac Arrest

Targeted temperature management (TTM) may moderate the injury from out-of-hospital cardiac arrest. Slowing the metabolism has been a suggested effect. Nevertheless, studies have found higher lactate levels in patients cooled to 33°C compared with 36°C even days from TTM cessation. Larger studies have not been performed on the TTM's effect on the metabolome. Accordingly, to explore the effect of TTM, we used ultra-performance liquid-mass spectrometry in a substudy of 146 patients randomized in the TTM trial to either 33°C or 36°C for 24 hours and quantified 60 circulating metabolites at the time of hospital arrival (T0) and 48 hours later (T48). From T0 to T48, profound changes to the metabolome were observed: tricarboxylic acid (TCA) cycle metabolites, amino acids, uric acid, and carnitine species all decreased. TTM significantly modified these changes in nine metabolites (Benjamini-Hochberg corrected false discovery rate <0.05): branched amino acids valine and leucine levels dropped more in the 33°C arm (change [95% confidence interval]: -60.9 μM [-70.8 to -50.9] vs. -36.0 μM [-45.8 to -26.3] and -35.5 μM [-43.1 to -27.8] vs. -21.2 μM [-28.7 to -13.6], respectively), whereas the TCA metabolites including malic acid and 2-oxoglutaric acid remained higher for the first 48 hours (-7.7 μM [-9.7 to -5.7] vs. -10.4 μM [-12.4 to -8.4] and -3 μM [-4.3 to -1.7] vs. -3.7 μM [-5 to -2.3]). Prostaglandin E2 only dropped in the TTM 36°C group. The results show that TTM affects the metabolism hours after normothermia have been reached. Clinical Trial Number: NCT01020916.

Cardiovascular changes induced by targeted mild hypercapnia after out of hospital cardiac arrest. A sub-study of the TAME cardiac arrest trial

AIM

Hypercapnia may elicit detrimental haemodynamic effects in critically ill patients. We aimed to investigate the consequences of targeted mild hypercapnia versus targeted normocapnia on pulmonary vascular resistance and right ventricular function in patients resuscitated from out-of-hospital cardiac arrest (OHCA).

METHODS

Pre-planned, single-centre, prospective, sub-study of the Targeted Therapeutic Mild Hypercapnia After Resuscitated Cardiac Arrest (TAME) trial. Patients were randomised to mild hypercapnia (PaCO2 = 6.7-7.3 kPa) or normocapnia (PaCO2 = 4.7-6.0 kPa) for 24 hours. Haemodynamic assessment was performed with right heart catheterisation and serial blood-gas analyses every4th hour for 48 hours.

RESULTS

We studied 84 patients. Mean pH was 7.24 (95% CI 7.22-7.30) and 7.32 (95% CI 7.31-7.34) with hypercapnia and normocapnia, respectively (P-group < 0.001). Pulmonary vascular resistance index (PVRI), pulmonary artery pulsatility index, and right atrial pressure did not differ between groups (P-group > 0.05). Mean cardiac index was higher with mild hypercapnia (P-group < 0.001): 2.0 (95% CI 1.85-2.1) vs 1.6 (95% CI 1.52-1.76) L/min/m2. Systemic vascular resistance index was 2579 dyne-sec/cm-5/ m2 (95% CI 2356-2830) with hypercapnia, and 3249 dyne-sec/cm-5/ m2 (95% CI 2930-3368) with normocapnia (P-group < 0.001). Stroke volumes (P-group = 0.013) and mixed venous oxygen saturation (P-group < 0.001) were higher in the hypercapnic group.

CONCLUSION

In resuscitated OHCA patients, targeting mild hypercapnia did not increase PVRI or worsen right ventricular function compared to normocapnia. Mild hypercapnia comparatively improved cardiac performance and mixed venous oxygen saturation.

Dynamics of Capillary Lactate Levels in Patients with Out-of-Hospital Cardiac Arrest

Background and Objectives: An effective strategy for cardiopulmonary resuscitation should be based on tissue perfusion. Our primary aim was to determine the association between capillary lactate values and initial rhythm as well as the probability of the return of spontaneous circulation in out-of-hospital cardiac arrest patients. Materials and Methods: This prospective observational cohort study included all patients with non-traumatic out-of-hospital cardiac arrest, older than 18 years, resuscitated by a prehospital emergency medical team between April 2020 and June 2021. Capillary lactate samples were collected at the time of arrival and every 10 min after the first measurement until the time of the return of spontaneous circulation (ROSC) or, if ROSC was not achieved, at the time of declaring death on the scene. Results: In total, 83 patients were enrolled in the study. ROSC was achieved in 28 patients (33.7%), 21 were admitted to hospital (26.3%), and 6 (7.23%) of them were discharged from hospital. At discharge, all patients had Cerebral Performance Category Scale 1 or 2. Initial capillary lactate values were significantly higher in patients with a non-shockable rhythm compared to the group with a shockable rhythm (9.19 ± 4.6 versus 6.43 ± 3.81; p = 0.037). A significant difference also persisted in a second value taken 10 min after the initial value (10.03 ± 5,19 versus 5.18 ± 3.47; p = 0.019). Capillary lactate values were higher in the ROSC group and non-ROSC group at the time of restored circulation (11.10 ± 6.59 and 6.77 ± 4.23, respectively; p = 0.047). Conclusions: Capillary lactate values are significantly higher in patients with a non-shockable first rhythm in out-of-hospital cardiac arrest (OHCA). There is also a significantly different rise in capillary lactate levels in patients with ROSC.

Nurses' experiences of provision family-centred care in the postresuscitation period: A qualitative study

AIM

This study aimed to explore nurses' experiences of providing family-centred care in the postresuscitation period.

DESIGN

An exploratory-descriptive qualitative design was used.

METHODS

In this qualitative study, in-depth, semi-structured interviews were conducted with 22 nurses in three educational hospitals. There were six participants who completed follow-up interviews to resolve questions generated during initial interviews. Data were analysed using conventional content analysis.

RESULTS

Five main categories were extracted: continuous monitoring, facilitation of attendance, involvement in care, informing and emotional support. Despite the lack of organizational policies and guidelines, nurses explained how they work to provide family-centred care for families, especially those they assessed as having less possibility of aggressive behaviour and those with a better understanding of their loved one's condition. To provide postresuscitation family-centred care, nurses facilitated family attendance, involved them in some basic nursing care, and provided information and emotional support to the family members.

CONCLUSION

Nurses attempted to follow the basic principles of family-centred care in the postresuscitation period. However, to improve the provision of care by nurses, it is necessary to embed family-centred care principles in institutional policies and guidelines and to conduct training for nurses.

IMPLICATIONS FOR THE PROFESSION

Iranian nurses are interested in engaged families in the postresuscitation period. Correct implementations of such care that include all families need institutional policies and guidelines.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

Soluble Urokinase-Type Plasminogen Activator Receptor in Comatose Survivors After Out-of-Hospital Cardiac Arrest Treated with Targeted Temperature Management

Exposure to whole-body ischemia/reperfusion after out-of-hospital cardiac arrest (OHCA) triggers a systemic inflammatory response where soluble urokinase plasminogen activator receptor (suPAR) is released. This study investigated serial levels of suPAR in differentiated target temperature management and the associations with mortality and 6-month neurological outcome. This is a single-center substudy of the randomized Targeted Temperature Management (TTM) for 24-hour versus 48-hour trial. In this analysis, we included 82 patients and measured serial levels of suPAR at 24, 48, and 72 hours after achievement of target temperature (32-34°C). We assessed all-cause mortality and neurological function evaluated by the Cerebral Performance Categories (CPC) at 6 months after OHCA. Levels of suPAR between TTH groups were evaluated in repeated measures mixed models. Mortality was assessed by the Kaplan-Meier method and serial measurements of suPAR (log2 transformed) were investigated by Cox proportional-hazards models. Good neurological outcome at 6 months was assessed by logistic regression analyses. Levels of suPAR were significantly different between TTH groups (pinteraction = 0.04) with the highest difference at 48 hours, 4.7 ng/mL (95% CI: 4.1-5.4 ng/mL) in the TTH24 group compared to 2.8 ng/mL (95% CI: 2.2-3.5 ng/mL) in the TTH48 group, p < 0.0001. Levels of suPAR above the median value were significantly associated with increased all-cause mortality at any time point (plog-rank<0.05). The interaction of suPAR levels and TTH group was not significant (pinteraction = NS). A twofold increase in levels of suPAR was significantly associated with a decreased odds ratio of a good neurological outcome in both unadjusted and adjusted analyses without interaction of TTH group (pinteraction = NS). Prolonged TTM of 48 hours versus 24 hours was associated with lower levels of suPAR. High levels of suPAR were associated with increased mortality and lower odds for good neurological outcome at 6 months with no significant interaction of TTH group.

Serial assessments of cardiac output and mixed venous oxygen saturation in comatose patients after out-of-hospital cardiac arrest

AIM

To assess the association with outcomes of cardiac index (CI) and mixed venous oxygen saturation (SvO2) in comatose patients resuscitated from out-of-hospital cardiac arrest (OHCA).

METHODS

In the cohort study of 789 patients included in the "BOX"-trial, 565 (77%) patients were included in this hemodynamic substudy (age 62 ± 13 years, male sex 81%). Pulmonary artery catheters were inserted shortly after ICU admission. CI and SvO2 were measured as soon as possible in the ICU and until awakening or death. The endpoints were all-cause mortality at 1 year and renal failure defined as need for renal replacement therapy.

RESULTS

First measured CI was median 1.7 (1.4-2.1) l/min/m2, and first measured SvO2 was median 67 (61-73) %. CI < median with SvO2 > median was present in 222 (39%), and low SvO2 with CI < median was present in 59 (11%). Spline analysis indicated that SvO2 value < 55% was associated with poor outcome. Low CI at admission was not significantly associated with mortality in multivariable analysis (p = 0.14). SvO2 was significantly inversely associated with mortality (hazard ratioadjusted: 0.91 (0.84-0.98) per 5% increase in SvO2, p = 0.01). SvO2 was significantly inversely associated with renal failure after adjusting for confounders (ORadjusted: 0.73 [0.62-0.86] per 5% increase in SvO2, p = 0.001). The combination of lower CI and lower SvO2 was associated with higher risk of mortality (hazard ratioadjusted: 1.54 (1.06-2.23) and renal failure (ORadjusted: 5.87 [2.34-14.73].

CONCLUSION

First measured SvO2 after resuscitation from OHCA was inversely associated with mortality and renal failure. If SvO2 and CI were below median, the risk of poor outcomes increased significantly.

REGISTRATION

The BOX-trial is registered at clinicaltrials.gov (NCT03141099, date 2017-30-04, retrospectively registered).

Meta-analysis of the effects of inert gases on cerebral ischemia-reperfusion injury

Recently, noble gas has become a hot spot within the medical field like respiratory organ cerebral anemia, acute urinary organ injury and transplantation. However, the shield performance in cerebral ischemia-reperfusion injury (CIRI) has not reached an accord. This study aims to evaluate existing evidence through meta-analysis to determine the effects of inert gases on the level of blood glucose, partial pressure of oxygen, and lactate levels in CIRI. We searched relevant articles within the following both Chinese and English databases: PubMed, Web of science, Embase, CNKI, Cochrane Library and Scopus. The search was conducted from the time of database establishment to the end of May 2023, and two researchers independently entered the data into Revman 5.3 and Stata 15.1. There were total 14 articles were enclosed within the search. The results showed that the amount of partial pressure of blood oxygen in the noble gas cluster was beyond that in the medicine gas cluster (P < 0.05), and the inert gas group had lower lactate acid and blood glucose levels than the medical gas group. The partial pressure of oxygen (SMD = 1.51, 95% CI 0.10 ~ 0.91 P = 0.04), the blood glucose level (SMD = - 0.59, 95% CI - 0.92 ~ - 0.27 P = 0.0004) and the lactic acid level (SMD = - 0.42, 95% CI - 0.80 ~ - 0.03 P = 0.03) (P < 0.05). These results are evaluated as medium-quality evidence. Inert gas can effectively regulate blood glucose level, partial pressure of oxygen and lactate level, and this regulatory function mainly plays a protective role in the small animal ischemia-reperfusion injury model. This finding provides an assessment and evidence of the effectiveness of inert gases for clinical practice, and provides the possibility for the application of noble gases in the treatment of CIRI. However, more operations are still needed before designing clinical trials, such as the analysis of the inhalation time, inhalation dose and efficacy of different inert gases, and the effective comparison of the effects in large-scale animal experiments.

Inflammatory response after out-of-hospital cardiac arrest-Impact on outcome and organ failure development

BACKGROUND

Post-cardiac arrest syndrome that occurs in out-of-hospital cardiac arrest (OHCA) patients is characterized by inflammatory response. We conducted a scoping review of current evidence regarding several inflammatory markers' usefulness for assessment of patient outcome and illness severity. We also discuss the proposed underlying mechanisms leading to inflammatory response after OHCA.

METHODS

We searched the MEDLINE, PubMed Central, Cochrane CENTRAL and Web of Science Core Collection databases with the following search terms: ("inflammation" OR "cytokines") AND "out-of-hospital cardiac arrest." Each inflammatory marker found was combined with "out-of-hospital cardiac arrest" using "AND" to find further relevant studies. We included original studies measuring inflammatory markers in adult OHCA patients that assessed their prognostic capabilities for mortality, neurological outcome, or organ failure severity.

RESULTS

Fifty-nine studies met the inclusion criteria, covering in total 65 different markers. Interleukin-6 (IL-6), procalcitonin (PCT) and C-reactive protein (CRP) were the most studied markers, and they were associated with poor outcomes in 13/15, 13/14 and 11/17 studies, respectively. Based on area under the receiver operating characteristic curve (AUC) value, the time point of best discriminatory capacity for poor outcome was ICU admission for IL-6 (median AUC 0.78, range 0.71-0.98) and day one after OHCA for PCT (median AUC 0.84, range 0.61-0.98). Seven studies reported AUCs for CRP (range 0.52-0.76) with no measurement time point being superior to others. The association of IL-6 and PCT with outcome appeared stronger in studies with more severely ill patients. Studies reported conflicting results regarding each marker's association with organ failure severity.

CONCLUSION

Inflammatory markers are potentially useful for early risk stratification after OHCA. PCT and IL-6 have moderate prognostic value during the first 24 h of the ICU stay. Predictive accuracy appears to be associated with the study overall event rate.