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.

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.

Predicting Survival Outcomes in Post-Cardiac Arrest Syndrome: The Impact of Combined Sequential Organ Failure Assessment Score and Serum Lactate Measurement

BACKGROUND Post-cardiac arrest syndrome (PCAS) is a major concern and shares pathophysiology with sepsis. Sequential organ failure assessment (SOFA) scores and serum lactate levels, as suggested in the Survival Sepsis Guidelines, have shown significant predictive value for prognosis in patients with sepsis. This retrospective study aimed to evaluate combined use of the SOFA score and serum lactate measurement on survival prognosis in PCAS. MATERIAL AND METHODS Our study included patients with return of spontaneous circulation after cardiac arrest who were age >18 years and underwent targeted temperature management. The 438 patients were allocated to a surviving group and a deceased group at discharge. Multivariable regression models were used to evaluate any association with SOFA scores, serum lactate levels, and survival. To evaluate the predictive value of regression models, the area under the receiver operating characteristic curve (AUROC) was assessed. RESULTS Lower SOFA score and serum lactate level were associated with better survival rates in the post-cardiac arrest patients (SOFA score: odds ratio (OR), 0.77; 95% confidence interval (CI), 0.67-0.88; P<0.001; lactate level: OR, 0.85; 95% CI, 0.81-0.94; P<0.001). The combined model of the SOFA score and serum lactate level was superior to models including either SOFA score or serum lactate level alone in predicting survival (AUROC, 0.86 vs 0.83, P=0.028, 0.86 vs 0.81, P=0.004). CONCLUSIONS Because of the superiority of the combined model of SOFA score and serum lactate level, combining these 2 factors could improve prediction of prognosis and survival outcomes in PCAS.

Time-course relationship between cerebrospinal fluid and serum concentrations of midazolam and albumin in patients with cardiac arrest undergoing targeted temperature management

AIM

To understand the serum and cerebrospinal fluid (CSF) distribution of midazolam is important for proper timing of neurological prognostication of targeted temperature management(TTM) patients. Midazolam binds extensively to albumin in serum although non protein bound form exist in CSF. We investigated the time-course of CSF, serum concentrations of midazolam and albumin in patients with cardiac arrest who underwent TTM.

METHODS

This prospective, single-center, observational study was conducted between May 2020 and April 2022. Midazolam and albumin concentrations in CSF and serum were quantified 0, 24, 48, and 72 h after the return of spontaneous circulation for comparison between the good (Cerebral Performance Category (CPC) 1 and 2) and poor (CPC 3, 4, and 5) neurologic outcome groups. The CSF/serum (C/S) ratios of midazolam and albumin concentrations were determined, along with their correlation coefficients.

RESULTS

Of the 19 enrolled patients, 13 experienced poor outcomes. At 0 h, serum midazolam concentrations were the lowest, whereas serum albumin levels were the highest; in the CSF, the concentrations of both peaked at 24 h. There were no significant inter-group differences in midazolam concentrations in CSF or serum. The C/S ratios of midazolam and albumin significantly differed between the groups. Moderate to strong positive correlations were observed between the midazolam and albumin C/S ratios.

CONCLUSION

In CSF, midazolam and albumin concentrations peaked 24 h post-cardiac arrest. Midazolam and albumin C/S ratios were significantly higher in the poor outcome group and positively correlated with each other, suggesting blood-brain barrier disruption 24 h post-cardiac arrest.

Validation of the rCAST Score and Comparison to the PCAC and FOUR Scores for Prognostication after Out-of-Hospital Cardiac Arrest

AIM

Early, accurate outcome prediction after out-of-hospital cardiac arrest (OHCA) is critical for clinical decision-making and resource allocation. We sought to validate the revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) score in a United States cohort and compare its prognostic performance to the Pittsburgh Cardiac Arrest Category (PCAC) and Full Outline of UnResponsiveness (FOUR) scores.

METHODS

This is a single-center, retrospective study of OHCA patients admitted between January 2014-August 2022. Area under the receiver operating curve (AUC) was computed for each score for predicting poor neurologic outcome at discharge and in-hospital mortality. We compared the scores' predictive abilities via Delong's test.

RESULTS

Of 505 OHCA patients with all scores available, the medians [IQR] for rCAST, PCAC, and FOUR scores were 9.5 [6.0, 11.5], 4 [3,4], and 2 [0, 5], respectively. The AUC [95% confidence interval] of the rCAST, PCAC, and FOUR scores for predicting poor neurologic outcome were 0.815 [0.763 - 0.867], 0.753 [0.697 - 0.809], and 0.841 [0.796 - 0.886], respectively. The AUC [95% confidence interval] of the rCAST, PCAC, and FOUR scores for predicting mortality were 0.799 [0.751 - 0.847], 0.723 [0.673 - 0.773], and 0.813 [0.770 - 0.855], respectively. The rCAST score was superior to the PCAC score for predicting mortality (p=0.017). The FOUR score was superior to the PCAC score for predicting poor neurological outcome (p<0.001) and mortality (p<0.001).

CONCLUSION

The rCAST score can reliably predict poor outcome in a United States cohort of OHCA patients regardless of TTM status and outperforms the PCAC score.

Does One Size Fit All? External Validation of the rCAST Score to Predict the Hospital Outcomes of Post-Cardiac Arrest Patients Receiving Targeted Temperature Management

The revised post-Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) score was proposed to predict neurologic outcomes and mortality among out-of-hospital cardiac arrest (OHCA) patients. However, it has rarely been validated outside Japan. Therefore, this study aimed to investigate this issue. All adult patients admitted to our medical intensive care unit for targeted temperature management (TTM) between July 2015 and July 2021 were enrolled. Their medical records were retrieved, and rCAST scores were calculated. A total of 108 post-cardiac arrest syndrome (PCAS) patients who received TTM were analyzed. According to the rCAST score, 49.1%, 50.0%, and 0.9% of the patients were classified as low, moderate, and high severity, respectively. The areas under the curves for the rCAST score were 0.806 (95% confidence interval [CI]: 0.719-0.876) and 0.794 (95% CI: 0.706-0.866) to predict poor neurologic outcomes and mortality at day 28, respectively. In contrast to the original report, only low-severity patients had favorable neurologic outcomes. The rCAST score showed moderate accuracy in our OHCA patients with PCAS who received TTM to predict poor neurologic outcomes and mortality at day 28.

Is there an association between 30-day mortality and adrenaline infusion rates in post-ROSC patients? A retrospective observational analysis

Introduction

Revised guidelines for the management of cardiac arrest have placed greater emphasis on early defibrillation and closed chest compressions; subsequently there has been a significant rise in the number of patients gaining a return of spontaneous circulation (ROSC). As a consequence, emergency medical services have realised the importance of therapies delivered during this phase of care. In some Trusts this includes the use of inotropic agents to augment the cardiovascular system and maintain adequate cerebral and coronary perfusion pressures to mitigate the effects of post-cardiac arrest syndrome. Currently, limited evidence exists with regards to the efficacy of such treatments in the pre-hospital phase.

Methods

Retrospective observational analysis of out-of-hospital cardiac arrest patients who received an adrenaline infusion by critical care paramedics. Infusion rates, time of call (ToC) to ROSC and 30-day mortality were compared.

Results

Over a 2-year period, 202 patients were recorded as having an adrenaline infusion commenced. Of these, 25 were excluded as they did not meet criteria or had incomplete data and 22 were excluded as the infusion was stopped at scene; 155 patients were admitted to hospital. There were no survivors in the non-shockable group and three survivors in the shockable group at 30 days. A rare events analysis found no relationship between infusion rate, ToC to ROSC and 30-day mortality (Wald chi2, 1.37).

Conclusion

Commencement of adrenaline infusions in post-ROSC was associated with significant 30-day mortality, especially in non-shockable rhythms. Further research is needed to elucidate whether this intervention has any benefit in the post-ROSC patient.

Serum total cholesterol level as a potential predictive biomarker for neurological outcomes in cardiac arrest survivors who underwent target temperature management

Cholesterol is an essential substance to maintain cell membranes. Low levels of total cholesterol (TC) are associated with poor prognosis in critically ill patients. Cardiac arrest-induced whole-body ischemia and reperfusion injury cause a sepsis-like syndrome. The Cholesterol level in post-cardiac arrest patients may indicate the degree of endotoxemia or inflammation caused by ischemic and reperfusion injury. We aimed to investigate the association of TC levels with neurologic outcome of out-of-hospital cardiac arrest (OHCA) survivors who underwent target temperature management (TTM). This was a retrospective single-center observational study from May 2018 to April 2021 on a cohort of 106 patients. TC levels were determined in samples obtained immediately and at 24, 48, and 72 hours after the return of spontaneous circulation (ROSC). The primary outcome was poor neurologic outcome at 3 months after ROSC. Poor neurologic outcome was defined by cerebral performance categories 3 to 5. Sixty patients had a poor neurologic outcome. TC levels were significantly lower in the poor neurologic outcome group at each time point. The TC levels for predicting poor neurologic outcome had a sensitivity of 80.8%, with 67.6% specificity at 48 hours (TC48) after ROSC. The areas under the curve value of TC48 was 0.771 (0.670-0.853), with a cutoff value of 114 mg/dL. TC level at 48 hours after ROSC was a helpful marker for the 3-month poor neurologic outcome. This might be an easily accessible predictive marker of neurologic outcome in OHCA survivors treated with TTM.

The immunology of the post-cardiac arrest syndrome

Patients successfully resuscitated from cardiac arrest often have brain injury, myocardial dysfunction, and systemic ischemia-reperfusion injury, collectively termed the post-cardiac arrest syndrome (PCAS). To improve outcomes, potential therapies must be able to be administered early in the post-arrest course and provide broad cytoprotection, as ischemia-reperfusion injury affects all organ systems. Our understanding of the immune system contributions to the PCAS has expanded, with animal models detailing biologically plausible mechanisms of secondary injury, the protective effects of available immunomodulatory drugs, and how immune dysregulation underlies infection susceptibility after arrest. In this narrative review, we discuss the dysregulated immune response in PCAS, human trials of targeted immunomodulation therapies, and future directions for immunomodulation following cardiac arrest.

Predisposing Factors and Neurologic Outcomes of Patients with Elevated Serum Amylase and/or Lipase after Out-of-Hospital Cardiac Arrest: A Retrospective Cohort Study

This study investigated the patient outcomes, incidence, and predisposing factors of elevated pancreatic enzyme levels after OHCA. We conducted a retrospective cohort study of patients treated with targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA). Elevation of pancreatic enzyme levels was defined as serum amylase or lipase levels that were at least three times the upper limit of normal. The factors associated with elevated pancreatic enzyme levels and their association with neurologic outcomes and mortality 28 days after OHCA were analyzed. Among the 355 patients, 166 (46.8%) patients developed elevated pancreatic enzyme levels. In the multivariable analysis (odds ratio, 95% confidence interval), initial shockable rhythm (0.62, 0.39−0.98, p = 0.04), time from collapse to return of spontaneous circulation (1.02, 1.01−1.04, p < 0.001), and history of coronary artery disease (1.7, 1.01−2.87, p = 0.046) were associated with elevated pancreatic enzyme levels. After adjusting for confounding factors, elevated pancreatic enzyme levels were associated with neurologic outcomes (5.44, 3.35−8.83, p < 0.001) and mortality (3.74, 2.39−5.86, p < 0.001). Increased pancreatic enzyme levels are common in patients treated with TTM after OHCA and are associated with unfavorable neurologic outcomes and mortality at 28 days after OHCA.

Differential Effectiveness of Hypothermic Targeted Temperature Management According to the Severity of Post-Cardiac Arrest Syndrome

International guidelines recommend targeted temperature management (TTM) to improve the neurological outcomes in adult patients with post-cardiac arrest syndrome (PCAS). However, it still remains unclear if the lower temperature setting (hypothermic TTM) or higher temperature setting (normothermic TTM) is superior for TTM. According to the most recent large randomized controlled trial (RCT), hypothermic TTM was not found to be associated with superior neurological outcomes than normothermic TTM in PCAS patients. Even though this represents high-quality evidence obtained from a well-designed large RCT, we believe that we still need to continue investigating the potential benefits of hypothermic TTM. In fact, several studies have indicated that the beneficial effect of hypothermic TTM differs according to the severity of PCAS, suggesting that there may be a subgroup of PCAS patients that is especially likely to benefit from hypothermic TTM. Herein, we summarize the results of major RCTs conducted to evaluate the beneficial effects of hypothermic TTM, review the recent literature suggesting the possibility that the therapeutic effect of hypothermic TTM differs according to the severity of PCAS, and discuss the potential of individualized TTM.

High platelet-lymphocyte ratio is a risk factor for 30-day mortality in in-hospital cardiac arrest patients: a case-control study

OBJECTIVES

This study explored the association of early dynamic changes in inflammatory markers with 30-day mortality in in-hospital cardiac arrest (IHCA) patients.

METHODS

This study retrospectively enrolled 85 IHCA patients. The outcome was 30-day mortality. A linear mixed model was used to analyze the dynamic changes in laboratory indicators within 72 h after recovery of spontaneous circulation(ROSC).

RESULTS

Within 72 h after ROSC, the absolute monocyte count (AMC) showed no significant change trend, and the absolute lymphocyte count (ALC) showed an overall upward trend, while the absolute neutral count (ANC), white blood cell (WBC) count, platelet (PLT) count, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and systemic immune-inflammation index (SII) showed overall downward trends. Cox multivariate analysis showed that the Charlson comorbidity index (CCI) (HR = 2.37, 95%CI (1.08, 5.17)), Acute Physiology and Chronic Health Evaluation II (APACHE II) score (HR = 2.55, 95% CI (1.00, 6.50)), abnormal creatinine level before IHCA (HR = 3.42, 95% CI (1.44, 8.10)) and PLR within 72 h after ROSC (HR = 2.99, 95% CI (1.44, 6.21)) were independent risk factors for 30-day mortality.

CONCLUSIONS

The PLR can be used as a predictor of 30-day mortality in IHCA patients.

Elevated Plasma Soluble PD-L1 Levels in Out-of-Hospital Cardiac Arrest Patients

Background: A deregulated immune system has been implicated in the pathogenesis of post-cardiac arrest syndrome (PCAS). A soluble form of programmed cell death-1 (PD-1) ligand (sPD-L1) has been found at increased levels in cancer and sustained inflammation, thereby deregulating immune functions. Here, we aim to study the possible involvement of sPD-L1 in PCAS. Methods: Thirty out-of-hospital cardiac arrest (OHCA) patients consecutively admitted to the ER of Mie University Hospital were prospectively enrolled. Plasma concentrations of sPD-L1 were measured by an enzyme-linked immunosorbent assay in blood samples of all 30 OHCA patients obtained during cardiopulmonary resuscitation (CPR). In 13 patients who achieved return-of-spontaneous-circulation (ROSC), sPD-L1 levels were also measured daily in the ICU. Results: The plasma concentrations of sPD-L1 in OHCA were significantly increased; in fact, to levels as high as those observed in sepsis. sPD-L1 levels during CPR correlated with reduced peripheral lymphocyte counts and increased C-reactive protein levels. Of 13 ROSC patients, 7 cases survived in the ICU for more than 4 days. A longitudinal analysis of sPD-L1 levels in the 7 ROSC cases revealed that sPD-L1 levels occurred in parallel with organ failure. Conclusions: This study suggests that ischemia- reperfusion during CPR may aberrantly activate immune and endothelial cells to release sPD-L1 into circulation, which may play a role in the pathogenesis of immune exhaustion and organ failures associated with PCAS.

Beyond return of spontaneous circulation: update on post-cardiac arrest management in the intensive care unit

A well-functioning chain of survival is critical for good outcomes following out-of-hospital cardiac arrest, a major public health concern in Singapore. While the percentage of survivors to hospital admission has increased over the years, the percentage of survivors to hospital discharge and the number of patients with good neurological recovery can be greatly improved. This underscores the urgent need to focus on 'post-cardiac arrest care', the fifth link in the chain of survival, to improve the outcomes of patients who are admitted to the intensive care unit (ICU) after return of spontaneous circulation. This review builds on earlier recommendations of the Singapore National Targeted Temperature Management Workgroup in 2017 to provide a focused update on post-cardiac arrest management and a practical guide for physicians managing resuscitated patients with cardiac arrest in the ICU.

Change of Hemoglobin Levels in the Early Post-cardiac Arrest Phase Is Associated With Outcome

Background: The post-cardiac arrest (CA) phase is characterized by high fluid requirements, endothelial activation and increased vascular permeability. Erythrocytes are large cells and may not leave circulation despite massive capillary leak. We hypothesized that dynamic changes in hemoglobin concentrations may reflect the degree of vascular permeability and may be associated with neurologic function after CA.

Methods: We included patients ≥18 years, who suffered a non-traumatic CA between 2013 and 2018 from the prospective Vienna Clinical Cardiac Arrest Registry. Patients without return of spontaneous circulation (ROSC), with extracorporeal life support, with any form of bleeding, undergoing surgery, receiving transfusions, without targeted temperature management or with incomplete datasets for multivariable analysis were excluded. The primary outcome was neurologic function at day 30 assessed by the Cerebral Performance Category scale. Differences of hemoglobin concentrations at admission and 12 h after ROSC were calculated and associations with neurologic function were investigated by uni- and multivariable logistic regression.

Results: Two hundred and seventy-five patients were eligible for analysis of which 143 (52%) had poor neurologic function. For every g/dl increase in hemoglobin from admission to 12 h the odds of poor neurologic function increased by 26% (crude OR 1.26, 1.07–1.49, p = 0.006). The effect remained unchanged after adjustment for fluid balance and traditional prognostication markers (adjusted OR 1.27, 1.05–1.54, p = 0.014).

Conclusion: Increasing hemoglobin levels in spite of a positive fluid balance may serve as a surrogate parameter of vascular permeability and are associated with poor neurologic function in the early post-cardiac arrest period.

Coagulopathy Induced by Veno-Arterial Extracorporeal Membrane Oxygenation Is Associated With a Poor Outcome in Patients With Out-of-Hospital Cardiac Arrest

Background: In recent years, the use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) in patients with cardiopulmonary arrest who do not respond to conventional resuscitation, has increased. However, despite the development of VA-ECMO, the outcomes of resuscitated patients remain poor. The poor prognosis may be attributed to deterioration owing to the post-cardiac arrest syndrome (PCAS); this includes the systemic inflammatory response and coagulation activation caused by the extracorporeal circulation (VA-ECMO circuit) itself. This study aimed to evaluate the coagulofibrinolytic changes caused by VA-ECMO and to identify predictive factors of poor prognosis.

Methods: We analyzed 151 cases of PCAS with witnessed cardiac arrest. As biomarkers, platelet counts, prothrombin time ratio, fibrin/fibrinogen degradation products, fibrinogen, antithrombin, and lactate were recorded from blood samples from the time of delivery to the third day of hospitalization. The maximum (max) and minimum (min) values of each factor during the study period were calculated. To evaluate the impact of VA-ECMO on patients with PCAS, we performed propensity score matching between the patients who received and did not receive VA-ECMO. Sub-analysis was performed for the group with VA-ECMO.

Results: There were significant differences in all baseline characteristics and demographics except the time from detection to hospital arrival, percentage of cardiopulmonary resuscitations (CPR) by witnesses, and the initial rhythm between the groups. Propensity score matching adjusted for prehospital factors demonstrated that the patients who received VA-ECMO developed significantly severe coagulation disorders. In a sub-analysis, significant differences were noted in the prothrombin time ratio min, fibrinogen max, antithrombin max, and lactate min between survivors and non-survivors. In particular, the prothrombin time ratio min and antithrombin max were strongly correlated with poor outcome.

Conclusion: In the present study, significant coagulopathy was observed in patients who received VA-ECMO for CPR. In particular, in patients receiving VA-ECMO, the minimum prothrombin time ratio and maximum antithrombin by day 3 of hospitalization were strongly correlated with poor outcomes. These results suggest that VA-ECMO-induced coagulopathy can be a promising therapeutic target for patients resuscitated by VA-ECMO.

Hydrogen Gas Therapy: From Preclinical Studies to Clinical Trials

BACKGROUND

Mounting evidence indicates that hydrogen gas (H₂) is a versatile therapeutic agent, even at very low, non-combustible concentrations. The Chinese National Health and Medical Commission recently recommended the use of inhaled H₂ in addition to O₂ therapy in the treatment of COVID-19-associated pneumonia, and its effects extend to anti-tumor, anti-inflammatory and antioxidant actions.

SUMMARY

In this review, we have highlighted key findings from preclinical research and recent clinical studies demonstrating that H₂ reduces the organ damage caused by ischemia-reperfusion. We have also outlined the critical role this effect plays in a variety of medical emergencies, including myocardial infarction, hemorrhagic shock, and out-of-hospital cardiac arrest, as well as in organ transplantation. H₂ is compared with established treatments such as targeted temperature management, and we have also discussed its possible mechanisms of action, including the recently identified suppression of TNF-α-mediated endothelial glycocalyx degradation by inhaled H₂. In addition, our new method that enables H₂ gas to be easily transported to emergency settings and quickly injected into an organ preservation solution at the site of donor organ procurement have been described.

CONCLUSION

H₂ is an easily administered, inexpensive and well-tolerated agent that is highly effective for a wide range of conditions in emergency medicine, as well as for preserving donated organs.

Neuroprotective Treatment of Postanoxic Encephalopathy: A Review of Clinical Evidence

Postanoxic encephalopathy is the key determinant of death or disability after successful cardiopulmonary resuscitation. Animal studies have provided proof-of-principle evidence of efficacy of divergent classes of neuroprotective treatments to promote brain recovery. However, apart from targeted temperature management (TTM), neuroprotective treatments are not included in current care of patients with postanoxic encephalopathy after cardiac arrest. We aimed to review the clinical evidence of efficacy of neuroprotective strategies to improve recovery of comatose patients after cardiac arrest and to propose future directions. We performed a systematic search of the literature to identify prospective, comparative clinical trials on interventions to improve neurological outcome of comatose patients after cardiac arrest. We included 53 studies on 21 interventions. None showed unequivocal benefit. TTM at 33 or 36°C and adrenaline (epinephrine) are studied most, followed by xenon, erythropoietin, and calcium antagonists. Lack of efficacy is associated with heterogeneity of patient groups and limited specificity of outcome measures. Ongoing and future trials will benefit from systematic collection of measures of baseline encephalopathy and sufficiently powered predefined subgroup analyses. Outcome measurement should include comprehensive neuropsychological follow-up, to show treatment effects that are not detectable by gross measures of functional recovery. To enhance translation from animal models to patients, studies under experimental conditions should adhere to strict methodological and publication guidelines.

A Case of Fatal Asthma: Rapid Transition to Cardiac Arrest and Rapid Recovery of Respiratory Status

The global mortality of bronchial asthma continues to decrease, with a reported 57% decline in age-standardized mortality rates between 1993 and 2006.Asthma may rarely be encountered as a cause of cardiac arrest on arrival in the emergency department these days, especially in high-income countries. Rapid worsening of symptoms and rapid improvement in respiratory status after initiation of treatment have been noted as a hallmark of cardiac arrest due to asthma. A 62-year-old male was admitted to our emergency department after dyspnea and dry coughing attack lasting approximately 15 minutes and resulted in cardiopulmonary arrest. His arterial blood gas analysis showed mixed acidosis with pH 7.00, partial pressure of oxygen (PaO₂) 184, partial pressure of carbon dioxide (PaCO₂) 90 mmHg, HCO₃^- 22.2, lactate 104 mg/dL. He returned to spontaneous circulation after about 30 minutes of cardiopulmonary arrest. The very slight wheeze on expiration was heard in the left lung and his chest x-ray showed increasing permeability of the lung, which suggested air trapping. Based on his history of asthma, the background of medication discontinuation, and physical findings, the diagnosis of cardiac arrest due to an asthma attack was made. Two hours after admission, PaCO₂ normalized and his respiratory condition stabilized rapidly. However, epileptic seizures due to hypoxic encephalopathy were prolonged. Although he was then managed in the intensive care unit, he was diagnosed with irreversible brain damage due to hypoxic encephalopathy and shifted to palliative care. Asthmatic cardiac arrest is now rare, but still important. And it may be difficult to identify asthma as a cause of cardiac arrest if the respiratory status improves rapidly. Therefore, keeping in mind the presence of asthma cases of rapid deterioration to cardiopulmonary arrest and case of rapid treatment response may lead to a correct diagnosis.

Haemodynamics and vasopressor support during prolonged targeted temperature management for 48 hours after out-of-hospital cardiac arrest: a post hoc substudy of a randomised clinical trial

BACKGROUND

Comatose patients admitted after out-of-hospital cardiac arrest frequently experience haemodynamic instability and anoxic brain injury. Targeted temperature management is used for neuroprotection; however, targeted temperature management also affects patients' haemodynamic status. This study assessed the haemodynamic status of out-of-hospital cardiac arrest survivors during prolonged (48 hours) targeted temperature management at 33°C.

METHODS

Analysis of haemodynamic and vasopressor data from 311 patients included in a randomised, clinical trial conducted in 10 European hospitals (the TTH48 trial). Patients were randomly allocated to targeted temperature management at 33°C for 24 (TTM24) or 48 (TTM48) hours. Vasopressor and haemodynamic data were reported hourly for 72 hours after admission. Vasopressor load was calculated as norepinephrine (µg/kg/min) plus dopamine(µg/kg/min/100) plus epinephrine (µg/kg/min).

RESULTS

After 24 hours, mean arterial pressure (mean±SD) was 74±9 versus 75±9 mmHg (P=0.19), heart rate was 57±16 and 55±14 beats/min (P=0.18), vasopressor load was 0.06 (0.03-0.15) versus 0.08 (0.03-0.15) µg/kg/min (P=0.22) for the TTM24 and TTM48 groups, respectively. From 24 to 48 hours, there was no difference in mean arterial pressure (Pgroup=0.32) or lactate (Pgroup=0.20), while heart rate was significantly lower (average difference 5 (95% confidence interval 2-8) beats/min, Pgroup<0.0001) and vasopressor load was significantly higher in the TTM48 group (Pgroup=0.005). In a univariate Cox regression model, high vasopressor load was associated with mortality in univariate analysis (hazard ratio 1.59 (1.05-2.42) P=0.03), but not in multivariate analysis (hazard ratio 0.77 (0.46-1.29) P=0.33).

CONCLUSIONS

In this study, prolonged targeted temperature management at 33°C for 48 hours was associated with higher vasopressor requirement but no sign of any detrimental haemodynamic effects.

Acute respiratory failure and inflammatory response after out-of-hospital cardiac arrest: results of the Post-Cardiac Arrest Syndrome (PCAS) pilot study

BACKGROUND

Although the lungs are potentially highly susceptible to post-cardiac arrest syndrome injury, the issue of acute respiratory failure after out-of-hospital cardiac arrest has not been investigated. The objectives of this analysis were to determine the prevalence of acute respiratory failure after out-of-hospital cardiac arrest, its association with post-cardiac arrest syndrome inflammatory response and to clarify its importance for early mortality.

METHODS

The Post-Cardiac Arrest Syndrome (PCAS) pilot study was a prospective, observational, six-centre project (Poland 2, Denmark 1, Spain 1, Italy 1, UK 1), studying patients resuscitated after out-of-hospital cardiac arrest of cardiac origin. Primary outcomes were: (a) the profile of organ failure within the first 72 hours after out-of-hospital cardiac arrest; (b) in-hospital and short-term mortality, up to 30 days of follow-up. Respiratory failure was defined using a modified version of the Berlin acute respiratory distress syndrome definition. Inflammatory response was defined using leukocytes (white blood cells), platelet count and C-reactive protein concentration. All parameters were assessed every 24 hours, from admission until 72 hours of stay.

RESULTS

Overall, 148 patients (age 62.9±15.27 years; 27.7% women) were included. Acute respiratory failure was noted in between 50 (33.8%) and 75 (50.7%) patients over the first 72 hours. In-hospital and short-term mortality was 68 (46.9%) and 72 (48.6%), respectively. Inflammation was significantly associated with the risk of acute respiratory failure, with the highest cumulative odds ratio of 748 at 72 hours (C-reactive protein 1.035 (1.001-1.070); 0.043, white blood cells 1.086 (1.039-1.136); 0.001, platelets 1.004 (1.001-1.007); <0.005). Early acute respiratory failure was related to in-hospital mortality (3.172, 95% confidence interval 1.496-6.725; 0.002) and to short-term mortality (3.335 (1.815-6.129); 0.0001).

CONCLUSIONS

An inflammatory response is significantly associated with acute respiratory failure early after out-of-hospital cardiac arrest. Acute respiratory failure is associated with a worse early prognosis after out-of-hospital cardiac arrest.

The Relationship Between Hematological Parameters and Mortality in Cardiovascular Patients With Postcardiac Arrest Syndrome

Background: Post-cardiac arrest syndrome is the insufficiency of cardiac and cerebral functions caused by ischemia after sudden cardiac arrest. We aimed to determine the hematological parameters associated with mortality in the intensive care follow-up of patients with post-cardiac arrest syndrome.

Methods: The hematological parameters of 285 cardiovascular patients who were admitted to the emergency department of Harran University Medical Faculty between 2013 and 2018 and followed up in the intensive care unit with post-cardiac arrest syndrome were examined. A total of 85 patients were included in the study. These parameters were recorded as the time of arrival to the emergency department (0 hour) and hematological parameters at the 24^th and 48^th hours of intensive care follow-up.

Results: In the mortality group, albumin (P:0.030), hemoglobin (Hg) (P: 0.049), and hematocrit (HCT) (P: 0.020) values ​​in the blood parameters, at the time of admission to the emergency department, were significantly lower than those in the survival group. Red blood cell distribution width (RDW) (P: 0.009) and urea (P <0.001) values ​​at the time of arrival were higher than the survival group. In the 24^th and 48^th hours, mean hemoglobin (MCHC) (P <0.05) values ​​were lower and RDW (P <0.05) values ​​were higher in the mortality group compared to the survival group.

Conclusions: In this retrospective validation, low albumin, Hg, HCT, MCHC, and high RDW and urea levels may increase mortality in cardiovascular patients who develop post-cardiac arrest syndrome within the first 48 hours. Correcting these values ​​early may reduce mortality.

[Target temperature in post-cardiac-arrest complex intensive care: arguments for mild therapeutic hypothermia]

Long term survival of successfully resuscitated patients is primarily determined by their post-cardiac arrest neurological function. If the patient undergoes a long-term resuscitation or remains comatose as part of the post-cardiac arrest syndrome (PCAS), organ-specific intensive care is urged to aim hemodynamic stabilisation, normalisation of organ perfusion and prevention of injuries at cellular level. One of the basic measures of PCAS intensive care is to prevent hypoxic brain injury by mild therapeutic hypothermia (THT). The physiological changes of the human body at hypothermic conditions require high level monitoring and specially focused intensive care limiting its implementation. The multicentric, controlled, randomized targeted temperature management (TTM) trial published in 2013 compared the TTM against the THT in the treatment of PCAS patients. The equal outcome of the 2 methods has partly changed the practice of the intensivists in the treatment of such patients. This manuscript gives the pros and cons for each therapeutic method in post-resuscitation therapy. Nevertheless, the author shows the possible implementations and the DRG (diagnosis-related group) reimbursement of the method in Hungary. Orv Hetil. 2019; 160(46): 1840-1844.

The post-cardiac arrest syndrome: A case for lung-brain coupling and opportunities for neuroprotection

Systemic inflammation and multi-organ failure represent hallmarks of the post-cardiac arrest syndrome (PCAS) and predict severe neurological injury and often fatal outcomes. Current interventions for cardiac arrest focus on the reversal of precipitating cardiac pathologies and the implementation of supportive measures with the goal of limiting damage to at-risk tissue. Despite the widespread use of targeted temperature management, there remain no proven approaches to manage reperfusion injury in the period following the return of spontaneous circulation. Recent evidence has implicated the lung as a moderator of systemic inflammation following remote somatic injury in part through effects on innate immune priming. In this review, we explore concepts related to lung-dependent innate immune priming and its potential role in PCAS. Specifically, we propose and investigate the conceptual model of lung-brain coupling drawing from the broader literature connecting tissue damage and acute lung injury with cerebral reperfusion injury. Subsequently, we consider the role that interventions designed to short-circuit lung-dependent immune priming might play in improving patient outcomes following cardiac arrest and possibly other acute neurological injuries.

Endothelial BMP4 Regulates Leukocyte Diapedesis and Promotes Inflammation

Leukocyte recruitment is a fundamental event in the response of the innate immune system to injury. This process is promoted in part by the opening of endothelial cell adherens junctions that allows leukocyte extravasation through gaps between adjacent endothelial cells. VE-cadherin is a key component of endothelial cell adherens junctions and a negative regulator of leukocyte emigration. Accumulating evidence implicates bone morphogenetic protein (BMP) 4 as a critical regulator in vascular biology, but its role in leukocyte extravasation in vitro and in vivo has not been investigated so far. To assess the impact of BMP4 on leukocyte emigration in vivo, we used the thioglycollate-induced peritonitis model. C57BL/6 mice were intraperitoneally (i.p.) injected with recombinant BMP4 in addition to thioglycollate. Compared to solvent-treated controls, we observed higher accumulation of leukocytes in the peritoneal lavage of BMP4-treated mice indicating that BMP4 promotes leukocyte diapedesis into the inflamed peritoneal cavity. Endothelial cell-specific deletion of BMP4 in mice markedly diminished leukocyte diapedesis following thioglycollate administration suggesting that endothelial BMP4 is required for leukocyte recruitment. Consistent with these in vivo results, transwell migration assays with human umbilical vein endothelial cells (HUVECs) in vitro revealed that recombinant BMP4 enhanced leukocyte transmigration through the endothelial monolayer. Conversely, silencing of endothelial BMP4 by siRNA dampened leukocyte diapedesis in vitro. Mechanistic studies showed that loss of BMP4 improved endothelial junction stability by upregulation of VE-cadherin expression in vitro and in vivo. Vice versa, treatment of HUVECs with recombinant BMP4 decreased expression of VE-cadherin and impaired endothelial junction stability shown by Western blotting and immunocytochemistry. Finally, severe endothelial damage in HUVECs in response to serum of patients collected 24 h after survived cardiac arrest was accompanied by increase in leukocyte migration in transwell assays and activation of the BMP pathway most probably by upregulation of endothelial BMP4 RNA and protein expression. Collectively, the present study provides novel evidence that endothelial BMP4 controls leukocyte recruitment through a VE-cadherin-dependent mechanism and that BMP4-induced inflammation might be involved in the pathogenesis of endothelial cell damage following successful resuscitation after cardiac arrest.

Efficacy of inhaled HYdrogen on neurological outcome following BRain Ischemia During post-cardiac arrest care (HYBRID II trial): study protocol for a randomized controlled trial

Background

Hydrogen gas inhalation (HI) improved survival and neurological outcomes in an animal model of post-cardiac arrest syndrome (PCAS). The feasibility and safety of HI for patients with PCAS was confirmed in a pilot study. The objective of this study is to evaluate the efficacy of HI for patients with PCAS.

Methods/design

The efficacy of inhaled HYdrogen on neurological outcome following BRain Ischemia During post-cardiac arrest care (HYBRID II) trial is an investigator-initiated, randomized, double-blind, placebo-controlled trial designed to enroll 360 adult comatose (Glasgow Coma Scale score < 8) patients who will be resuscitated following an out-of-hospital cardiac arrest of a presumed cardiac cause. The patients will be randomized (1:1) to either the HI or control group. Patients in the HI group will inhale 2% hydrogen with 24% to 50% oxygen, and those in the control group will inhale 24% to 50% oxygen for 18 h after admission via mechanical ventilation. Multidisciplinary post-arrest care, including targeted temperature management (TTM) between 33 °C and 36 °C, will be provided in accordance with the latest guidelines. The primary outcome of interest is the 90-day neurological outcome, as evaluated using the Cerebral Performance Categories scale (CPC). The secondary outcomes of interest are the 90-day survival rate and other neurological outcomes. This study will provide 80% power to detect a 15% change in the proportion of patients with good neurological outcomes (CPCs of 1 and 2), from 50% to 65%, with an overall significance level of 0.05.

Discussion

The first multicenter randomized trial is underway to confirm the efficacy of HI on neurological outcomes in comatose out-of-hospital cardiac arrest survivors. Our study has the potential to address HI as an appealing and innovative therapeutic strategy for PCAS in combination with TTM.

Trials registration

University Hospital Medical Information Network (UMIN), 000019820. Registered on 17 November 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2246-3) contains supplementary material, which is available to authorized users.

Coagulofibrinolytic Changes in Patients with Post-cardiac Arrest Syndrome

Whole-body ischemia and reperfusion due to cardiac arrest and subsequent return of spontaneous circulation constitute post-cardiac arrest syndrome (PCAS), which consists of four syndromes including systemic ischemia/reperfusion responses and post-cardiac arrest brain injury. The major pathophysiologies underlying systemic ischemia/reperfusion responses are systemic inflammatory response syndrome and increased coagulation, leading to disseminated intravascular coagulation (DIC), which clinically manifests as obstruction of microcirculation and multiple organ dysfunction. In particular, thrombotic occlusion in the brain due to DIC, referred to as the "no-reflow phenomenon," may be deeply involved in post-cardiac arrest brain injury, which is the leading cause of mortality in patients with PCAS. Coagulofibrinolytic changes in patients with PCAS are characterized by tissue factor-dependent coagulation, which is accelerated by impaired anticoagulant mechanisms, including antithrombin, protein C, thrombomodulin, and tissue factor pathway inhibitor. Damage-associated molecular patterns (DAMPs) accelerate not only tissue factor-dependent coagulation but also the factor XII- and factor XI-dependent activation of coagulation. Inflammatory cytokines are also involved in these changes via the expression of tissue factor on endothelial cells and monocytes, the inhibition of anticoagulant systems, and the release of neutrophil elastase from neutrophils activated by inflammatory cytokines. Hyperfibrinolysis in the early phase of PCAS is followed by inadequate endogenous fibrinolysis and fibrinolytic shutdown by plasminogen activator inhibitor-1. Moreover, cell-free DNA, which is also a DAMP, plays a pivotal role in the inhibition of fibrinolysis. DIC diagnosis criteria or fibrinolysis markers, including d-dimer and fibrin/fibrinogen degradation products, which are commonly tested in patients and easily accessible, can be used to predict the mortality or neurological outcome of PCAS patients with high accuracy. A number of studies have explored therapy for this unique pathophysiology since the first report on "no-reflow phenomenon" was published roughly 50 years ago. However, the optimum therapeutic strategy focusing on the coagulofibrinolytic changes in cardiac arrest or PCAS patients has not yet been established. The elucidation of more precise pathomechanisms of coagulofibrinolytic changes in PCAS may aid in the development of novel therapeutic targets, leading to an improvement in the outcomes of PCAS patients.

Effects of Therapeutic Hypothermia for Neuroprotection from the Viewpoint of Redox Regulation

Redox regulation has recently been recognized as an important factor in acute illnesses as well as in chronic diseases. It has also become a target for neuroprotection in acute intensive care. Despite its well-known therapeutic effects, therapeutic hypothermia has recently been re-evaluated for its potential use in emergency and critical care medicine. Hypothermia is an undesirable physiological condition that can increase oxidative stress and decrease anti-oxidative potency. However, many studies have shown that under ischemia/reperfusion conditions, therapeutic hypothermia actually suppresses enhanced oxidative stress and maintains or increases anti-oxidative potency. This review provides an overview and outlook for the future of therapeutic hypothermia for neuroprotection from the perspective of redox regulation in patients with post-cardiac arrest syndrome and traumatic brain injury.

Neuronal injury and tumor necrosis factor-alpha immunoreactivity in the rat hippocampus in the early period of asphyxia-induced cardiac arrest under normothermia

Low survival rate occurs in patients who initially experience a spontaneous return of circulation after cardiac arrest (CA). In this study, we induced asphyxial CA in adult male Sprague-Daley rats, maintained their body temperature at 37 ± 0.5°C, and then observed the survival rate during the post-resuscitation phase. We examined neuronal damage in the hippocampus using cresyl violet (CV) and Fluore-Jade B (F-J B) staining, and pro-inflammatory response using ionized calcium-binding adapter molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), and tumor necrosis factor-alpha (TNF-α) immunohistochemistry in the hippocampus after asphyxial CA in rats under normothermia. Our results show that the survival rate decreased gradually post-CA (about 63% at 6 hours, 37% at 1 day, and 8% at 2 days post-CA). Rats were sacrificed at these points in time post-CA, and no neuronal damage was found in the hippocampus until 1 day post-CA. However, some neurons in the stratum pyramidale of the CA region in the hippocampus were dead 2 days post-CA. Iba-1 immunoreactive microglia in the CA1 region did not change until 1 day post-CA, and they were activated (enlarged cell bodies with short and thicken processes) in all layers 2 days post-CA. Meanwhile, GFAP-immunoreactive astrocytes did not change significantly until 2 days post-CA. TNF-α immunoreactivity decreased significantly in neurons of the stratum pyramidale in the CA1 region 6 hours post-CA, decreased gradually until 1 day post-CA, and increased significantly again 2 days post-CA. These findings suggest that low survival rate of normothermic rats in the early period of asphyxia-induced CA is related to increased TNF-α immunoreactivity, but not to neuronal damage in the hippocampal CA1 region.

Alterations in Cerebral Blood Flow after Resuscitation from Cardiac Arrest

Greater than 50% of patients successfully resuscitated from cardiac arrest have evidence of neurological disability. Numerous studies in children and adults, as well as in animal models have demonstrated that cerebral blood flow (CBF) is impaired after cardiac arrest. Stages of cerebral perfusion post-resuscitation include early hyperemia, followed by hypoperfusion, and finally either resolution of normal blood flow or protracted hyperemia. At the level of the microcirculation the blood flow is heterogeneous, with areas of no flow, low flow, and increased flow. CBF directed therapies in animal models of cardiac arrest improved neurological outcome, and therefore, the alterations in CBF after cardiac arrest likely contribute to the development of hypoxic ischemic encephalopathy. Current intensive care after cardiac arrest is centered upon maintaining systemic oxygenation, normal blood pressure values for age, maintaining general homeostasis, and avoiding hyperthermia. Assessment of CBF and oxygenation is not routinely performed after cardiac arrest. Currently available and underutilized techniques to assess cerebral perfusion include transcranial doppler, near-infrared spectroscopy, and arterial spin labeling magnetic resonance imaging. Limited clinical studies established the role of CBF and oxygenation monitoring in prognostication after cardiac arrest and few studies suggest that guiding critical care post-resuscitation to mean arterial pressures above the minimal autoregulatory range might improve outcome. Important knowledge gaps thus remain in cerebral monitoring and CBF and oxygen goal-directed therapies post-resuscitation from cardiac arrest.

Coagulofibrinolytic changes in patients with disseminated intravascular coagulation associated with post-cardiac arrest syndrome--fibrinolytic shutdown and insufficient activation of fibrinolysis lead to organ dysfunction

INTRODUCTION

Post-cardiac arrest syndrome (PCAS) is often associated with disseminated intravascular coagulation (DIC), thus leading to the development of multiple organ dysfunction syndrome (MODS). The aim of this study was to examine the pathophysiological relationships between coagulation, fibrinolysis and fibrinolytic shutdown by evaluating the levels of coagulofibrinolytic markers, including soluble fibrin, thrombin-activatable fibrinolysis inhibitor (TAFI), tissue plasminogen activator-plasminogen activator inhibitor-1 complex (tPAIC), plasmin-alpha2 plasmin inhibitor complex (PPIC), neutrophil elastase and fibrin degradation product by neutrophil elastase (EXDP).

MATERIALS AND METHODS

Fifty-two resuscitated patients were divided into two groups: 22 DIC and 30 non-DIC patients.

RESULTS

The levels of soluble fibrin, PPIC, tPAIC, EXDP and neutrophil elastase in the DIC patients with PCAS were significantly higher than those observed in the non-DIC patients. The values of the tPAIC and JAAM DIC scores were found to be independent predictors of increased SOFA scores in the DIC patients. The MODS patients demonstrated significantly higher levels of soluble fibrin and tPAIC; however, the levels of TAFI and EXDP were identical between the patients with and without MODS. In addition, positive correlations were observed between the levels of tPAIC and EXDP in the patients with non-MODS; however, no correlations were observed between these markers in the MODS patients.

CONCLUSIONS

Thrombin activation and fibrinolytic shutdown play important roles in the development of organ dysfunction in PCAS patients. Neutrophil elastase-mediated fibrinolysis cannot overcome the fibrinolytic shutdown that occurs in DIC patients with PCAS, thus resulting in the development of MODS.

The role of the immuno-inflammatory response in patients after cardiac arrest

INTRODUCTION

The aim of the research was to assess whether concentrations of inflammatory markers in blood of patients after cardiac arrest (CA) are related to their clinical state and survival.

MATERIAL AND METHODS

Forty-six patients, aged 63 ±12 years, 21 of them after out-of-hospital CA and 25 after in-hospital CA, were enrolled in the study. Twenty-five patients survived and were discharged from hospital (CA-S); 21 died during hospitalization (CA-D). The clinical state of the patients was evaluated by the Glasgow Coma Scale (GCS) and the Acute Physiology and Chronic Health Evaluation II (APACHE II). On the day immediately after CA (day 1) and on the following day (day 2) the plasma concentration of high specific C-reactive protein (hs-CRP), tumour necrosis factor (TNF)-α, interleukin-10 and interleukin-6 (Ile-6) were measured.

RESULTS

In CA-D patients, compared with CA-S, a significantly higher concentration of hs-CRP (on day 1, 19 ±5 vs. 15 ±4; on day 2, 21 ±3 vs. 16 ±5 mg/l, p < 0.001) and Ile-6 (on day 1, 24.9 ±19.8 vs. 9.2 ±11.3; on day 2, 24.2 ±19.7 vs. 6.9 ±6.8 IU/ml, p < 0.001) was found. The level of TNF-α was greater in CA-D on day 1 (0.42 ±0.75 vs. 0.18 ±0.21 IU/ml, p < 0.04). Concentrations of hs-CRP and Ile-6 were correlated with the scores of GCS and APACHE II. Using logistic regression analysis and ROC curves the prognostic value of hs-CRP and Ile-6 for survival was proven.

CONCLUSIONS

Post-cardiac arrest immuno-inflammatory response, reflected mainly in elevated plasma concentration of hs-CRP and Ile-6, is not only correlated with patients' clinical state but also with prediction of survival.

Outcome measures utilized in clinical trials of interventions for post-cardiac arrest syndrome: a systematic review

BACKGROUND

The post-cardiac arrest syndrome (period of critical illness following return of spontaneous circulation [ROSC]) is a promising window of opportunity for clinical trials of therapeutic interventions to improve outcome from cardiac arrest. However, the methodological rigor of post-ROSC trials and the ability to compare or pool data on treatment effects across studies requires consistent and appropriate outcome measures. We aimed to determine the current degree of uniformity of outcome measures in clinical trials of post-ROSC interventions.

METHODS

We conducted a systematic review of Cochrane Library, MEDLINE, EMBASE, CINAHL, conference proceedings, and clinical trial registrations using a comprehensive strategy. We identified experimental or quasi-experimental trials testing post-ROSC interventions in adults. Four authors independently extracted data and assessed study quality using standardized instruments.

RESULTS

The search yielded 33 potential studies, of which 13 randomized controlled trials (n=1937) were included in the final analysis. Seven trials tested pharmacologic therapies and six tested non-pharmacologic therapies. Our main finding is that heterogeneity in the selection and reporting of outcomes limited comparability of results across studies. No two trials used exactly the same primary outcome, and timing of measurement varied widely. We found only two commonalities: (1) indices of functional survival were used rather than survival alone, and (2) ordinal scales of neurological function were collapsed into clinically meaningful groups ("good" versus "bad" outcome).

CONCLUSION

Currently there is a lack of uniformity in selection and reporting of outcome measures among trials of post-ROSC interventions. Achieving consensus would be an important advance for resuscitation science.