PCO2 on arrival as a predictive biomarker in patients with out-of-hospital cardiac arrest

BACKGROUND

Treating patients with out-of-hospital cardiac arrest (OHCA) requires early prediction of outcome, ideally on hospital arrival, as it can inform the clinical decisions involved. This study evaluated whether partial pressure of carbon dioxide (PCO₂) on arrival is associated with outcome at one month OHCA patients.

METHODS

This was a single-center retrospective study of adult OHCA patients treated between January 2016 and December 2020. Outcomes were defined along the Cerebral Performance Category (CPC) scale. Primary outcome was mortality (CPC 5) at one month. Secondary outcomes were death or unfavorable neurological outcome (CPC 3-5) and unfavorable neurological outcome (CPC 3-4) at one month. Multivariable analysis was adjusted for age, sex, witnessed cardiac arrest, bystander cardiopulmonary resuscitation, initial shockable rhythm, and time from call to emergency medical services to hospital arrival.

RESULTS

Out of 977 OHCA patients in the study period, 19 were excluded because they were aged under 18 years, 79 because they underwent extracorporeal cardiopulmonary resuscitation, and 101 due to lack of PCO₂ data. This study included 778 patients total; mortality (CPC 5) at one month was observed in 706 (90.7%), death or unfavorable neurological outcome (CPC 3-5) in 743 (95.5%), and unfavorable neurological outcome (CPC 3-4) in 37 (4.8%). In multivariable analysis, high PCO₂ levels showed significant association with mortality (CPC 5) at one month (odds ratio [OR] [per 5 mmHg], 1.14; 95% confidence interval [CI], 1.08-1.21), death or unfavorable neurological outcome (CPC 3-5) (OR [per 5 mmHg], 1.29; 95% CI, 1.17-1.42), and unfavorable neurological outcome (CPC 3-4) (OR [per 5 mmHg], 1.21; 95% CI, 1.04-1.41).

CONCLUSIONS

High PCO₂ on arrival was significantly associated with mortality and unfavorable neurological outcome in OHCA patients.

Neurological Prognostic Value of Adjusted Ca2+ Concentration in Adult Patients with Out-of-Hospital Cardiac Arrest

Many patients are transferred to hospital due to out-of-hospital cardiac arrest (OHCA), and, unfortunately, most suffer from cerebral damage. Currently, it is difficult to predict the recovery of neurological function after return of spontaneous circulation (ROSC) in the acute phase. Increased intracellular Ca²⁺ induces cell death in the acute phase. Accordingly, we predicted that serum adjusted Ca²⁺ will decrease following Ca²⁺ influx into cells. Consequently, serum adjusted Ca²⁺ in the acute phase may be able to predict recovery of neurological function in patients with ROSC from OHCA. This is a retrospective and observational study from 2 centers. A total of 190 consecutive patients with ROSC from OHCA were recruited, with 33 patients meeting the inclusion criteria. The relationship between serum adjusted Ca²⁺ within 48 hours after ROSC and neurological function at discharge (as evaluated by the Glasgow-Pittsburgh cerebral performance category) was examined. Serum adjusted Ca²⁺ was measured every 4 hours within a 48-hour period after ROSC. There were no significant differences in hemodynamical state and laboratory data between the 2 groups. However, lowest serum adjusted Ca²⁺ within 48 hours after ROSC was significantly lower in the poor neurological outcome group (0.96 ± 0.06 versus 1.02 ± 0.06 mmol/L, P = 0.011). Thus, lowest serum adjusted Ca²⁺ within 48 hours after ROSC may be a predictive factor for recovery of neurological function at discharge in patients with ROSC from OHCA.

Mechanical Cardiopulmonary Resuscitation and Hospital Survival Among Adult Patients With Nontraumatic Out-of-Hospital Cardiac Arrest Attending the Emergency Department: A Prospective, Multicenter, Observational Study in Japan (SOS-KANTO [Survey of Survivors after Out-of-Hospital Cardiac Arrest in Kanto Area] 2012 Study)

Background

Mechanical cardiopulmonary resuscitation (mCPR) for patients with out‐of‐hospital cardiac arrest attending the emergency department has become more widespread in Japan. The objective of this study is to determine the association between the mCPR in the emergency department and clinical outcomes.

Methods and Results

In a prospective, multicenter, observational study, adult patients with out‐of‐hospital cardiac arrest with sustained circulatory arrest on hospital arrival were identified. The primary outcome was survival to hospital discharge. The secondary outcomes included a return of spontaneous circulation and successful hospital admission. Multivariate analyses adjusted for potential confounders and within‐institution clustering effects using a generalized estimation equation were used to analyze the association of the mCPR with outcomes. Between January 1, 2012 and March 31, 2013, 6537 patients with out‐of‐hospital cardiac arrest were eligible; this included 5619 patients (86.0%) in the manual CPR group and 918 patients (14.0%) in the mCPR group. Of those patients, 28.1% (1801/6419) showed return of spontaneous circulation in the emergency department, 20.4% (1175/5754) had hospital admission, 2.6% (168/6504) survived to hospital discharge, and 1.2% (75/6419) showed a favorable neurological outcome at 1 month after admission. Multivariate analyses revealed that mCPR was associated with a decreased likelihood of survival to hospital discharge (adjusted odds ratio, 0.40; 95% confidence interval, 0.20–0.78; P=0.005), return of spontaneous circulation (adjusted odds ratio, 0.71; 95% confidence interval, 0.53–0.94; P=0.018), and hospital admission (adjusted odds ratio, 0.57; 95% confidence interval, 0.40–0.80; P=0.001).

Conclusions

After accounting for potential confounders, the mCPR in the emergency department was associated with decreased likelihoods of good clinical outcomes after adult nontraumatic out‐of‐hospital cardiac arrest. Further studies are needed to clarify circumstances in which mCPR may benefit these patients.

Initial Blood Ammonia Level Is a Useful Prognostication Tool in Out-of-Hospital Cardiac Arrest - Multicenter Prospective Study (SOS-KANTO 2012 Study)

BACKGROUND

Initial blood ammonia level is associated with neurologic outcomes in out-of-hospital cardiac arrest (OHCA). We tested the usefulness of blood ammonia for prediction of long-term neurological outcome of OHCA.Methods and Results:A total of 3,011 hospitalized adult OHCA patients were enrolled. Blood samples were obtained at the ED. Cut-offs (ammonia <100 μmol/L and lactate <12 mmol/L) were determined in a previous study. Neurological outcomes in survivors were assessed at 3 months. A logistic regression model with adjustment for within-hospital clustering and other risk factors was used to evaluate the association between biomarkers and outcomes. Of 3,011 patients, 380 (13.8%) had favorable neurological outcomes. Ammonia and lactate predicted neurological outcome with an AUC of 0.80 (95% CI: 0.76-0.84) and 0.77 (95% CI: 0.72-0.82), respectively. Adjusted OR for ammonia <100 μmol/L (4.55; 95% CI: 2.67-7.81) was higher than that for lactate <12 mmol/L (2.63; 95% CI: 1.61-4.28) and most other risk factors, such as cardiac etiology (3.47; 95% CI: 2.55-4.72), age<80 years (3.16; 95% CI: 2.17-4.61), bystander CPR (2.39; 95% CI: 1.70-3.38), and initial rhythm shockable (1.66; 95% CI: 1.16-2.37). The combination of ammonia and lactate had an increased predictive value (AUC, 0.86; 95% CI: 0.85-0.87) compared with that without biomarkers (AUC, 0.81; 95% CI: 0.80-0.82).

CONCLUSIONS

Initial blood ammonia level is as useful as other traditional prognostic indicators such as lactate. Measurement of both initial blood ammonia and lactate helped accurately predict neurological outcomes after OHCA.

Global Registry of Acute Coronary Events risk score predicts mortality and neurological outcome in out-of hospital cardiac arrest

PURPOSE

The aim of this study was to assess the usefulness of the Global Registry of Acute Coronary Events (GRACE) risk score in predicting in-hospital mortality and neurological outcome of patients resuscitated after out-of-hospital cardiac arrest (OHCA).

METHODS

We retrospectively analyzed the data of patients admitted to our hospital between October 2009 and October 2015 with OHCA and shockable initial cardiac rhythm who were resuscitated via conventional cardiopulmonary resuscitation. We calculated the GRACE risk score on admission and assessed its usefulness in predicting in-hospital mortality and neurological outcome.

RESULTS

Among 91 patients, 42 (46%) had acute myocardial infarction (AMI), 19 (21%) died in-hospital, and 52 (57%) had favorable neurological outcome. Among all the study patients, GRACE risk score was lower in survivors than in non-survivors (median 211 [interquartile range 176-240] vs. 266 [219-301], p<0.001, respectively) and in favorable than in unfavorable neurological outcome group (202 [167-237] vs. 242 [219-275], p<0.001, respectively). Multivariate analysis showed significant association between GRACE risk score and favorable neurological outcome (odds ratio, 0.975; 95% confidence interval, 0.961-0.990). Areas under receiver-operating characteristic curves, that describe the accuracy of GRACE risk score in predicting in-hospital mortality and favorable neurological outcome, were both 0.79.

CONCLUSION

GRACE risk score may predict the in-hospital mortality and neurological outcome associated with resuscitated patients with OHCA and shockable initial cardiac rhythm, regardless of the cause of arrest.

Hyperammonaemia and associated factors in unprovoked convulsive seizures: A cross-sectional study

PURPOSE

Hyperammonaemia is frequently observed in patients who have experienced convulsive seizures. Although excessive muscle contraction is presumed to be responsible for the elevated levels of ammonia, the underlying mechanism is poorly understood. The present study aimed to identify the independent factors associated with ammonia elevation using large-scale multivariate analysis.

METHODS

We conducted a cross-sectional study involving 379 adult patients who had been transported to our emergency department and treated for unprovoked convulsive seizures between August 2010 and September 2015. Elevation of venous plasma ammonia levels was set as the primary endpoint, and patients' clinical and laboratory data were obtained. Those with severe liver dysfunction, known hepatic encephalopathy, or convulsions due to cardiovascular or psychogenic causes, and those taking valproate were excluded.

RESULTS

Using a cut-off value of 50μg/dL, 183 patients (48.3%) were found to have elevated levels of plasma ammonia. Four factors were identified as independent variables associated with hyperammonaemia following seizures: elevated venous lactate, lowered venous pH, sex (male), and longer duration of convulsion.

CONCLUSIONS

The results of the present study revealed independent factors associated with hyperammonaemia following unprovoked convulsive seizures in a larger scale and with more plausible statistical analysis. The authors further suggest that the excessive skeletal muscle contraction and/or respiratory failure during/after convulsive seizure may be the primary mechanism of hyperammonaemia.

Decreased a disintegrin-like and metalloprotease with thrombospondin type 1 motif 13 activity and neurologic outcome in patients with successful resuscitation of out-of-hospital cardiac arrest: A prospective observational study

PURPOSE

The purpose of this study is to investigate the association between a disintegrin-like and metalloprotease with thrombospondin type 1 motif 13 (ADAMTS13) and neurologic outcome in patients with resuscitation of out-of-hospital cardiac arrest (R-OHCA).

MATERIALS AND METHODS

A prospective observational study of adult patients with R-OHCA was conducted. Plasma activity of ADAMTS13 and inflammatory markers, an immunologic marker, and a marker of endothelial damage were measured on admission and day 2. Neurologic outcome was evaluated using the Cerebral Performance Categories on day 90.

RESULTS

Plasma activity of ADAMTS13 on day 2 was lower in patients with poor neurologic outcome (n = 18) than that in those with good neurologic outcome (n = 16; P = .008). It was also lower in 28-day nonsurvivors (n = 12) than in survivors (n = 21; P = .019). Soluble thrombomodulin showed a strong correlation with ADAMTS13 (P = .021). Furthermore, ADAMTS13 activity was negatively correlated with the Sequential Organ Failure Assessment score (P < .001), levels of high-mobility group box 1 (P = .028), and levels of interleukin 6 (P = .047) but positively correlated with the monocyte expression of human leukocyte antigen DR (P = .023).

CONCLUSION

Decreased ADAMTS13 activity was associated with poor neurologic outcome, high mortality, and worsened immune-inflammatory status in patients with R-OHCA. These results suggest that ADAMTS13 may have pathophysiologic relevance in postcardiac arrest syndrome.

Monitoring biomarkers of cellular injury and death in acute brain injury

BACKGROUND

Molecular biomarkers have revolutionalized diagnosis and treatment of many diseases, such as troponin use in myocardial infarction. Urgent need for high-fidelity biomarkers in neurocritical care has resulted in numerous studies reporting potential candidate biomarkers.

METHODS

We performed an electronic literature search and systematic review of English language articles on cellular/molecular biomarkers associated with outcome and with disease-specific secondary complications in adult patients with acute ischemic stroke (AIS), intracerebral hemorrhage (ICH), subarachnoid hemorrhage (SAH), traumatic brain injury (TBI), and post-cardiac arrest hypoxic ischemic encephalopathic injuries (HIE).

RESULTS

A total of 135 articles were included. Though a wide variety of potential biomarkers have been identified, only neuron-specific enolase has been validated in large cohorts and shows 100% specificity for poor outcome prediction in HIE patients not treated with therapeutic hypothermia. There are many promising candidate blood and CSF biomarkers in SAH, AIS, ICH, and TBI, but none yet meets criteria for routine clinical use.

CONCLUSION

Current studies vary significantly in patient selection, biosample collection/processing, and biomarker measurement protocols, thereby limiting the generalizability of overall results. Future large prospective studies with standardized treatment, biosample collection, and biomarker measurement and validation protocols are necessary to identify high-fidelity biomarkers in neurocritical care.

Assessment of adverse events and predictors of neurological recovery after therapeutic hypothermia

BACKGROUND

Therapeutic hypothermia improves neurological recovery after witnessed cardiac arrest from ventricular fibrillation or tachycardia. Its application is expanding despite associated adverse events.

OBJECTIVE

To assess the occurrence of adverse events and predictors of good versus poor neurological recovery after therapeutic hypothermia.

METHODS

A single-center, retrospective review of medical records of 91 patients who received therapeutic hypothermia for ≥6 hours. Adverse events included laboratory abnormalities, shivering, acute kidney injury, or infection. Cerebral performance categories (CPC) scores delineated good (CPC of 1-3) or poor (CPC of 4 or 5) neurological outcomes. Groups were compared and parameters evaluated for effect on neurological recovery using backward logistic regression analysis.

RESULTS

Therapeutic hypothermia was used for several indications, and 42 patients (46.2%) had good neurological recovery. Demographic parameters were similar between groups. Common adverse events were hypoglycemia (98.9%), shivering (84.6%), bradycardia (58.2%), electrolyte abnormalities (26.4%-91.2%), acute kidney injury (52.8%), infection (48.4%), and coagulopathy (40.7%). Characteristics independently associated with neurological recovery included faster return of spontaneous circulation (ROSC), quicker initiation of cooling, and the occurrence of infections. Pulseless electrical activity, faster achievement of goal cooling temperature, seizure, and the administration of insulin or epinephrine were inversely related to neurological recovery.

CONCLUSIONS

Adverse events of therapeutic hypothermia were numerous and frequent, necessitating monitoring. Neurological recovery is primarily driven by the type of arrest, the rapidity of ROSC, the time needed to provide and achieve therapeutic hypothermia, the development of seizures or infection, and the use of insulin or epinephrine.