Thrombolytics in Cardiac Arrest from Pulmonary Embolism: A Systematic Review and Meta Analysis

BACKGROUND

During cardiopulmonary resuscitation, intravenous thrombolytics are commonly used for patients whose underlying etiology of cardiac arrest is presumed to be related to pulmonary embolism (PE).

METHODS

We performed a systematic review and meta-analysis of the existing literature that focused on the use of thrombolytics for cardiac arrest due to presumed or confirmed PE. Outcomes of interest were return of spontaneous circulation (ROSC), survival to hospital discharge, neurologically-intact survival, and bleeding complications.

RESULTS

Thirteen studies with a total of 803 patients were included in this review. Most studies included were single-armed and retrospective. Thrombolytic agent and dose were heterogeneous between studies. Among those with control groups, intravenous thrombolysis was associated with higher rates of ROSC (OR 2.55, 95% CI = 1.50-4.34), but without a significant difference in survival to hospital discharge (OR 1.41, 95% CI = 0.79-2.41) or bleeding complications (OR 2.21, 0.95-5.17).

CONCLUSIONS

Use of intravenous thrombolytics in cardiac arrest due to confirmed or presumed PE is associated with increased ROSC but not survival to hospital discharge or change in bleeding complications. Larger randomized studies are needed. Currently, we recommend continuing to follow existing consensus guidelines which support use of thrombolytics for this indication.

Comparison of various vasopressin doses to epinephrine during cardiopulmonary resuscitation in asphyxiated neonatal piglets

BACKGROUND

Current neonatal resuscitation guidelines recommend epinephrine for cardiac arrest. Vasopressin might be an alternative during asphyxial cardiac arrest. We aimed to compare vasopressin and epinephrine on incidence and time to return of spontaneous circulation (ROSC) in asphyxiated newborn piglets.

DESIGN/METHODS

Newborn piglets (n = 8/group) were anesthetized, intubated, instrumented, and exposed to 30 min of normocapnic hypoxia, followed by asphyxia and asystolic cardiac arrest. Piglets were randomized to 0.2, 0.4, or 0.8IU/kg vasopressin, or 0.02 mg/kg epinephrine. Hemodynamic parameters were continuously measured.

RESULTS

Median (IQR) time to ROSC was 172(103-418)s, 157(100-413)s, 122(93-289)s, and 276(117-480)s for 0.2, 0.4, 0.8IU/kg vasopressin, and 0.02 mg/kg epinephrine groups, respectively (p = 0.59). The number of piglets that achieved ROSC was 6(75%), 6(75%), 7(88%), and 5(63%) for 0.2, 0.4, 0.8IU/kg vasopressin, and 0.02 mg/kg epinephrine, respectively (p = 0.94). The epinephrine group had a 60% (3/5) rate of post-ROSC survival compared to 83% (5/6), 83% (5/6), and 57% (4/7) in the 0.2, 0.4, and 0.8IU/kg vasopressin groups, respectively (p = 0.61).

CONCLUSION

Time to and incidence of ROSC were not different between all vasopressin dosages and epinephrine. However, non-significantly lower time to ROSC and higher post-ROSC survival in vasopressin groups warrant further investigation.

IMPACT

Time to and incidence of ROSC were not statistically different between all vasopressin dosages and epinephrine. Non-significantly lower time to ROSC and higher post-ROSC survival in vasopressin-treated piglets. Overall poorer hemodynamic recovery following ROSC in epinephrine piglets compared to vasopressin groups. Human neonatal clinical trials examining the efficacy of vasopressin during asphyxial cardiac arrest will begin recruitment soon.

Sodium octanoate alleviates cardiac and cerebral injury after traumatic cardiac arrest in a porcine model

INTRODUCTION

Traumatic cardiac arrest (TCA) is a severe condition with a high mortality rate, and patients who survive from TCA face a poor prognosis due to post-resuscitation injury, including cardiac and cerebral injury, which remains a serious challenge. Sodium octanoate has shown protective effects against various diseases. The present study aims to investigate sodium octanoate's protective effects against cardiac and cerebral injury after TCA in a porcine model.

METHODS

The study included a total of 22 male domestic pigs divided into three groups: Sham group (n = 7), TCA group (n = 7), and sodium octanoate (SO) group (n = 8). Hemorrhage was initiated via the right femoral artery by a blood pump at a rate of 2 ml·kg-1·min-1 to establish TCA model. The Sham group underwent only endotracheal intubation and arteriovenous catheterization, without experiencing the blood loss/cardiac arrest/resuscitation model. At 5 min after resuscitation, the SO group received a continuous sodium octanoate infusion while the TCA group received the same volume of saline. General indicators were monitored, and blood samples were collected at baseline and at different time points after resuscitation. At 24 h after resuscitation, pigs were sacrificed, and heart and brain were obtained for cell apoptosis detection, iron deposition staining, oxidative stress detection, and the expression of ferroptosis-related proteins (ACSL4 and GPX4).

RESULTS

Sodium octanoate significantly improved mean arterial pressure, cardiac output and ejection fraction induced by TCA. Serum biomarkers of cardiac and cerebral injury were found to increase at all time points after resuscitation, while sodium octanoate significantly reduced their levels. The apoptosis rates of cardiomyocytes and cerebral cortex cells in the SO group were significantly lower than in the TCA group, along with a reduced area of iron deposition staining. The sodium octanoate also reduced oxidative stress and down-regulated ferroptosis which was indicated by protein level alteration of ACSL4 and GPX4.

CONCLUSION

Our study's findings suggest that early infusion of sodium octanoate significantly alleviates post-resuscitation cardiac and cerebral injury in a porcine model of TCA, possibly through inhibition of cell apoptosis and GPX4-mediated ferroptosis. Therefore, sodium octanoate could be a potential therapeutic strategy for patients with TCA.

Effects of Endotracheal Epinephrine on Pharmacokinetics and Survival in a Swine Pediatric Cardiac Arrest Model

OBJECTIVES

The aim of this study was to compare the endotracheal tube (ET) and intravenous (IV) administration of epinephrine relative to concentration maximum, time to maximum concentration, mean concentration over time (MC), area under the curve, odds, and time to return of spontaneous circulation (ROSC) in a normovolemic pediatric cardiac arrest model.

METHODS

Male swine weighing 24-37 kg were assigned to 4 groups: ET (n = 8), IV (n = 7), cardiopulmonary resuscitation (CPR) + defibrillation (CPR + Defib) (n = 5), and CPR only (n = 3). Swine were placed arrest for 2 minutes, and then CPR was initiated for 2 minutes. Epinephrine (0.1 mg/kg) for the ET group or 0.01 mg/kg for the IV was administered every 4 minutes or until ROSC. Defibrillation started at 3 minutes and continued every 2 minutes for 30 minutes or until ROSC for all groups except the CPR-only group. Blood samples were collected over a period of 5 minutes.

RESULTS

The MC of plasma epinephrine for the IV group was significantly higher at the 30- and 60-second time points (P = 0.001). The ET group had a significantly higher MC of epinephrine at the 180- and 240-second time points (P < 0.05). The concentration maximum of plasma epinephrine was significantly lower for the ET group (195 ± 32 ng/mL) than for the IV group (428 ± 38 ng/mL) (P = 0.01). The time to maximum concentration was significantly longer for the ET group (145 ± 26 seconds) than for the IV group (42 ± 16 seconds) (P = 0.01). No significant difference existed in area under the curve between the 2 groups (P = 0.62). The odds of ROSC were 7.7 times greater for the ET versus IV group. Time to ROSC was not significantly different among the IV, ET, and CPR + Defib groups (P = 0.31).

CONCLUSIONS

Based on the results of this study, the ET route of administration should be considered a first-line intervention.

Norepinephrine versus epinephrine for hemodynamic support in post-cardiac arrest shock: A systematic review

PURPOSE

The preferred vasopressor in post-cardiac arrest shock has not been established with robust clinical outcomes data. Our goal was to perform a systematic review and meta-analysis comparing rates of in-hospital mortality, refractory shock, and hemodynamic parameters in post-cardiac arrest patients who received either norepinephrine or epinephrine as primary vasopressor support.

METHODS

We conducted a search of PubMed, Cochrane Library, and CINAHL from 2000 to 2022. Included studies were prospective, retrospective, or published abstracts comparing norepinephrine and epinephrine in adults with post-cardiac arrest shock or with cardiogenic shock and extractable post-cardiac arrest data. The primary outcome of interest was in-hospital mortality. Other outcomes included incidence of arrhythmias or refractory shock.

RESULTS

The database search returned 2646 studies. Two studies involving 853 participants were included in the systematic review. The proposed meta-analysis was deferred due to low yield. Crude incidence of in-hospital mortality was numerically higher in the epinephrine group compared with norepinephrine in both studies, but only statistically significant in one. Risk of bias was moderate to severe for in-hospital mortality. Additional outcomes were reported differently between studies, minimizing direct comparison.

CONCLUSION

The vasopressor with the best mortality and hemodynamic outcomes in post-cardiac arrest shock remains unclear. Randomized studies are crucial to remedy this.

Glucose control and outcomes in diabetic and nondiabetic patients treated with targeted temperature management after cardiac arrest

Hyperglycemia is commonly observed in critically ill patients and postcardiac arrest patients, with higher glucose levels and variability associated with poorer outcomes. In this study, we aim to compare glucose control in diabetic and nondiabetic patients using glycated hemoglobin (HbA1c) levels, providing insights for better glucose management strategies. This retrospective observational study was conducted at Seoul St. Mary's Hospital from February 2009 to May 2022. Blood glucose levels were measured hourly for 48 h after return of spontaneous circulation (ROSC), and a glucose management protocol was followed to maintain arterial blood glucose levels between 140 and 180 mg/dL using short-acting insulin infusion. Patients were categorized into four groups based on diabetes status and glycemic control. The primary outcomes assessed were neurological outcome and mortality at 6 months after cardiac arrest. Among the 332 included patients, 83 (25.0%) had a previous diabetes diagnosis, and 114 (34.3%) had an HbA1c of 6.0% or higher. At least one hyperglycemic episode was observed in 314 patients (94.6%) and hypoglycemia was found in 63 patients (19.0%) during 48 h. After the categorization, unrecognized diabetes was noticed in 51 patients with median HbA1c of 6.3% (interquartile range [IQR] 6.1-6.6). Patients with inadequate diabetes control had the highest initial HbA1c level (7.0%, IQR 6.5-7.8) and admission glucose (314 mg/dL, IQR 257-424). Median time to target glucose in controlled diabetes was significantly shorter with the slowest glucose reducing rate. The total insulin dose required to reach the target glucose level and cumulative insulin requirement during 48 h were different among the categories (p <0.001). Poor neurological outcomes and mortality were more frequently observed in patients with diagnosed diabetes. Occurrence of a hypoglycemic episode during the 48 h after ROSC was independently associated with poor neurologic outcomes (odds ratio [OR] 3.505; 95% confidence interval [CI], 2.382-9.663). Surviving patients following cardiac arrest exhibited variations in glucose hemodynamics and outcomes according to the categories based on their preexisting diabetes status and glycemic condition. Specifically, even experiencing a single episode of hypoglycemia during the acute phase could have an influence on unfavorable neurological outcomes. While the classification did not directly affect neurological outcomes, the present results indicate the need for a customized approach to glucose control based on these categories.

Sodium Bicarbonate and Calcium Chloride for the Treatment of Hyperkalemia-Induced Cardiac Arrest: A Randomized, Blinded, Placebo-Controlled Animal Study

OBJECTIVES

Current international guidelines recommend administrating calcium chloride and sodium bicarbonate to patients with hyperkalemia-induced cardiac arrest, despite limited evidence. The aim of this study was to evaluate the efficacy of calcium chloride and sodium bicarbonate on return of spontaneous circulation (ROSC) in a pig model of hyperkalemia-induced cardiac arrest.

DESIGN

A randomized, blinded, placebo-controlled experimental pig study. Hyperkalemia was induced by continuous infusion of potassium chloride over 45 minutes followed by a bolus. After a no flow period of 7 minutes, pigs first received 2 minutes of basic cardiopulmonary resuscitation and subsequently advanced life support. The first intervention dose was administered after the fifth rhythm analysis, followed by a defibrillation attempt at the sixth rhythm analysis. A second dose of the intervention was administered after the seventh rhythm analysis if ROSC was not achieved. In case of successful resuscitation, pigs received intensive care for 1 hour before termination of the study.

SETTING

University hospital laboratory.

SUBJECTS

Fifty-four female Landrace/Yorkshire/Duroc pigs (38-42 kg).

INTERVENTIONS

The study used a 2 × 2 factorial design, with calcium chloride (0.1 mmol/kg) and sodium bicarbonate (1 mmol/kg) as the interventions.

MEASUREMENTS AND MAIN RESULTS

Fifty-two pigs were included in the study. Sodium bicarbonate significantly increased the number of animals achieving ROSC (24/26 [92%] vs. 13/26 [50%]; odds ratio [OR], 12.0; 95% CI, 2.3-61.5; p = 0.003) and reduced time to ROSC (hazard ratio [HR] 3.6; 95% CI, 1.8-7.5; p < 0.001). There was no effect of calcium chloride on the number of animals achieving ROSC (19/26 [73%] vs. 18/26 [69%]; OR, 1.2; 95% CI, 0.4-4.0; p = 0.76) or time to ROSC (HR, 1.5; 95% CI, 0.8-2.9; p = 0.23).

CONCLUSIONS

Administration of sodium bicarbonate significantly increased the number of animals achieving ROSC and decreased time to ROSC. There was no effect of calcium chloride on the number of animals achieving ROSC or time to ROSC.

Effect of first epinephrine administration time on cerebral perfusion pressure and cortical cerebral blood flow in a porcine cardiac arrest model

OBJECTIVE

The optimal time for epinephrine administration and its effects on cerebral blood flow (CBF) and microcirculation remain controversial. This study aimed to assess the effect of the first administration of epinephrine on cerebral perfusion pressure (CePP) and cortical CBF in porcine cardiac arrest model.

METHODS

After 4 min of untreated ventricular fibrillation, eight of 24 swine were randomly assigned to the early, intermediate, and late groups. In each group, epinephrine was administered intravenously at 5, 10, and 15 min after cardiac arrest induction. CePP was calculated as the difference between the mean arterial pressure and intracranial pressure. Cortical CBF was measured using a laser Doppler flow probe. The outcomes were CePP and cortical CBF measured continuously during cardiopulmonary resuscitation (CPR). Mean CePP and cortical CBF were compared using analysis of variance and a linear mixed model.

RESULTS

The mean CePP was significantly different between the groups at 6-11 min after cardiac arrest induction. The mean CePP in the early group was significantly higher than that in the intermediate group at 8-10 min and that in the late group at 6-9 min and 10-11 min. The mean cortical CBF was significantly different between the groups at 9-11 min. The mean cortical CBF was significantly higher in the early group than in the intermediate and late group at 9-10 min.

CONCLUSION

Early administration of epinephrine was associated with improved CePP and cortical CBF compared to intermediate or late administration during the early period of CPR.

End-tidal carbon dioxide after sodium bicarbonate infusion during mechanical ventilation or ongoing cardiopulmonary resuscitation

PURPOSE

End-tidal CO2 is used to monitor the ventilation status or hemodynamic efficacy during mechanical ventilation or cardiopulmonary resuscitation (CPR), and it may be affected by various factors including sodium bicarbonate administration. This study investigated changes in end-tidal CO2 after sodium bicarbonate administration.

MATERIALS AND METHODS

This single-center, prospective observational study included adult patients who received sodium bicarbonate during mechanical ventilation or CPR. End-tidal CO2 elevation was defined as an increase of ≥20% from the baseline end-tidal CO2 value. The time to initial increase (lag time, Tlag), time to peak (Tpeak), and duration of the end-tidal CO2 rise (Tduration) were compared between the patients with spontaneous circulation (SC group) and those with ongoing resuscitation (CPR group).

RESULTS

Thirty-three patients, (SC group, n = 25; CPR group, n = 8), were included. Compared with the baseline value, the median values of peak end-tidal CO2 after sodium bicarbonate injection increased by 100% (from 21 to 41 mmHg) in all patients, 89.5% (from 21 to 39 mmHg) in the SC group, and 160.2% (from 15 to 41 mmHg) in the CPR group. The median Tlag was 17 s (IQR: 12-21) and the median Tpeak was 35 s (IQR: 27-52). The median Tduration was 420 s (IQR: 90-639). The median Tlag, Tpeak, and Tduration were not significantly different between the groups. Tduration was associated with the amount of sodium bicarbonate for SC group (correlation coefficient: 0.531, p = 0.006).

CONCLUSION

The administration of sodium bicarbonate may lead to a substantial increase in end-tidal CO2 for several minutes in patients with spontaneous circulation and in patients with ongoing CPR. After intravenous administration of sodium bicarbonate, the use of end-tidal CO2 pressure as a physiological indicator may be limited.

Evaluation of hydroxocobalamin use for the treatment of suspected cyanide toxicity secondary to smoke inhalation

Hydroxocobalamin is used for cyanide toxicity after smoke inhalation, but diagnosis is challenging. Retrospective studies have associated hydroxocobalamin with acute kidney injury (AKI). This is a retrospective analysis of patients receiving hydroxocobalamin for suspected cyanide toxicity. The primary outcome was the proportion of patients meeting predefined appropriate use criteria defined as ≥1 of the following: serum lactate ≥8 mmol/L, systolic blood pressure (SBP) <90 mmHg, new-onset seizure, cardiac arrest, or respiratory arrest. Secondary outcomes included incidence of AKI, pneumonia, resolution of initial neurologic symptoms, and in-hospital mortality. Forty-six patients were included; 35 (76%) met the primary outcome. All met appropriate use criteria due to respiratory arrest, 15 (43%) for lactate, 14 (40%) for SBP, 12 (34%) for cardiac arrest. AKI, pneumonia, and resolution of neurologic symptoms occurred in 30%, 21%, and 49% of patients, respectively. In-hospital mortality was higher in patients meeting criteria, 49% vs. 9% (95% CI 0.16, 0.64). When appropriate use criteria were modified to exclude respiratory arrest in a post-hoc analysis, differences were maintained, suggesting respiratory arrest alone is not a critical component to determine hydroxocobalamin administration. Predefined appropriate use criteria identify severely ill smoke inhalation victims and provides hydroxocobalamin treatment guidance.

Cardiac Agents during Neonatal Cardiopulmonary Resuscitation

BACKGROUND

Epinephrine (adrenaline) is currently the only cardiac agent recommended during neonatal resuscitation. The inability to predict which newborns are at risk of requiring resuscitative efforts at birth has prevented the collection of large, high-quality human data.

SUMMARY

Information on the optimal dosage and route of epinephrine administration is extrapolated from neonatal animal studies and human adult and pediatric studies. Adult resuscitation guidelines have previously recommended vasopressin use; however, neonatal studies needed to create guidelines are lacking. A review of the literature demonstrates conflicting results regarding epinephrine efficacy through various routes of access as well as vasopressin during asystolic cardiac arrest in animal models. Vasopressin appears to improve hemodynamic and post-resuscitation outcomes compared to epinephrine in asystolic cardiac arrest animal models.

KEY MESSAGES

The current neonatal resuscitation guidelines recommend epinephrine be primarily given via the intravenous or intraosseous route, with the endotracheal route as an alternative if these routes are not feasible or unsuccessful. The intravenous or intraosseous dose ranges between 0.01 and 0.03 mg/kg, which should be repeated every 3-5 min during chest compressions. However, the optimal dosing and route of administration of epinephrine remain unknown. There is evidence from adult and pediatric studies that vasopressin might be an alternative to epinephrine; however, the neonatal data are scarce.

Outcomes with intracoronary vs. intravenous epinephrine in cardiac arrest

BACKGROUND

Advanced Cardiovascular Life Support (ACLS) guidelines recommend intravenous (IV) and intraosseous (IO) epinephrine as a basic cornerstone in the resuscitation process. Data about the efficacy and safety of intracoronary (IC) epinephrine during cardiac arrest in the catheterization laboratory are lacking.

OBJECTIVE

To examine the efficacy and safety of IC vs. IV epinephrine for resuscitation during cardiac arrest in the catheterization laboratory.

METHODS AND RESULTS

This is a prospective observational study that included all patients who experienced cardiac arrest in the cath lab at two tertiary centres in Egypt from January 2015 to July 2022. Patients were divided into two groups according to the route of epinephrine given; IC vs. IV. The primary outcome was survival to hospital discharge. Secondary outcomes included rate of return of spontaneous circulation (ROSC), time-to-ROSC, and favourable neurological outcome at discharge defined as modified Rankin Scale (MRS) <3. A total of 162 patients met our inclusion criteria, mean age (60.69 ± 9.61), 34.6% women. Of them, 52 patients received IC epinephrine, and 110 patients received IV epinephrine as part of the resuscitation. Survival to hospital discharge was significantly higher in the IC epinephrine group (84.62% vs. 53.64%, P < 0.001) compared with the IV epinephrine group. The rate of ROSC was higher in the IC epinephrine group (94.23% vs. 70%, P < 0.001) and achieved in a shorter time (2.6 ± 1.97 min vs. 6.8 ± 2.11 min, P < 0.0001) compared with the IV group. Similarly, favourable neurological outcomes were more common in the IC epinephrine group (76.92% vs. 47.27%, P < 0.001) compared with the IV epinephrine group.

CONCLUSION

In this observational study, IC epinephrine during cardiac arrest in the cath lab appeared to be safe and may be associated with improved outcomes compared with the IV route. Larger randomized studies are encouraged to confirm these results.

A Case of Severe Lead Encephalopathy with Cardiac Arrest Managed During a Chelation Shortage

INTRODUCTION

For many years, the standard of care in the USA has been to treat acute lead encephalopathy with a combination parenteral dimercaprol (BAL) and CaNa2EDTA. We present a case of a pediatric patient with severe lead encephalopathy, complicated by cardiac arrest, who was treated with an alternative regimen when CaNa2EDTA was unavailable.

CASE REPORT

A 24-month-old male was brought by ambulance to an emergency department (ED) with new onset seizures and sustained a cardiac arrest. An initial blood lead concentration returned at 263 mcg/dl. The hospital was unable to obtain CaNa2EDTA due to the nationwide shortage. For this reason, the patient was chelated with BAL IM for 12 days and dimercaptosuccinic acid (DMSA) for 28 days. He received a second 5-day course of BAL due to rebounding blood lead concentrations. Eight days after cardiac arrest, he was extubated; however, despite ongoing therapy, subsequent follow-up 2 months later demonstrated persistent cognitive deficits.

DISCUSSION

The combination of DMSA and BAL was effective in rapidly decreasing whole blood lead concentrations. Drug shortages continue to have implications for the management of poisoned patients. This case highlights how shortages of chelating agents complicate patient care.

Effect of no-flow period on the vasopressor effect of initial epinephrine administration in cardiac arrest

OBJECTIVES

Whether a longer no-flow (NF) interval affects the magnitude of response to epinephrine in the resuscitation has not been well studied. Therefore, this study aimed to evaluate the effect of NF interval on the vasopressor effect of initial epinephrine administration in a porcine model.

METHODS

We enrolled 20 pigs from two randomized porcine experimental studies using a ventricular fibrillation (VF) cardiac arrest model. The first experiment subjects were resuscitated after 4 min of NF (Short NF group), followed by three cycles (6 min) of chest compression using a mechanical cardiopulmonary resuscitation device before epinephrine administration. Second experiment subjects received 6 min of NF (Long NF group), two cycles (4 min) of chest compressions, and administration of epinephrine. Defibrillation for VF was delivered 8 and 10 min after VF induction in the Short NF and Long NF groups, respectively. The mean arterial pressure (MAP) and cerebral perfusion pressure (CePP) in the 2-min resuscitation period after epinephrine administration were compared between the study groups using the Wilcoxon rank-sum test. The mean differences in the parameters between phases were also compared.

RESULTS

Seven pigs in the Short NF group and 13 pigs in the Long NF group were included in the analysis. All 2-min resuscitation phases from 6 to 16 min after VF induction were compared between the study groups. The Short NF group showed higher MAP and CePP in all phases (p < 0.01). Change of mean MAP after the epinephrine administration was significantly different between the study groups: mean difference (95% confidence interval) of 16.6 (15.8-17.4) mmHg in the Short NF group and 4.2 (3.9-4.5) mmHg in the Long NF group.

CONCLUSION

In the porcine VF cardiac arrest model, 6 min of NF before resuscitation may affect the vasopressor effect of the initial epinephrine administered compared to 4 min of NF. A short NF may play a role in maximizing the effect of epinephrine in advanced cardiovascular life support.

Apixaban versus no anticoagulation for the prevention of venous thromboembolism in children with newly diagnosed acute lymphoblastic leukaemia or lymphoma (PREVAPIX-ALL): a phase 3, open-label, randomised, controlled trial

BACKGROUND

Paediatric patients with acute lymphoblastic leukaemia or lymphoma are at increased risk of venous thromboembolism resulting in increased mortality and morbidity. We hypothesised that apixaban, a direct oral anticoagulant, would safely reduce venous thromboembolism in this patient population.

METHODS

PREVAPIX-ALL was a phase 3, open-label, randomised, controlled trial conducted in 74 paediatric hospitals in 9 countries. Participants aged 1 year or older to younger than 18 years with newly diagnosed acute lymphoblastic leukaemia (pre-B cell or T cell) or lymphoblastic lymphoma (B cell or T cell immunophenotype) and a central venous line in place throughout induction were randomly assigned 1:1 to standard of care (SOC, ie, no systemic anticoagulation) or weight-adjusted twice-daily apixaban during induction. Randomisation was performed centrally and stratified by age (those <10 years or those ≥10 years). Participants weighing 35 kg or less were administered 2·5 mg twice daily of apixaban as a 2·5 mg tablet, 0·5 mg tablets, or 0·4 mg/mL oral solution, while those weighing more than 35 kg were administered weight-adjusted prophylactic doses using 0·5 mg tablets or the 0·4 mg/mL oral solution twice daily. Primary outcomes were assessed by a blinded central adjudication committee. The primary efficacy outcome for the intention to treat population was the composite of symptomatic or clinically unsuspected venous thromboembolism, the primary safety outcome was major bleeding, and secondary safety outcomes included clinically relevant non-major (CRNM) bleeding. Patients were screened for venous thromboembolism by ultrasound and echocardiogram at the end of induction. The trial was registered with ClinicalTrials.gov (NCT02369653) and is now complete.

FINDINGS

Between Oct 22, 2015, and June 4, 2021, 512 participants were randomly assigned and included in analyses (222 [43%] female and 290 [57%] male; 388 [76%] White, 52 [10%] Asian, 24 [5%] Black or African American, and 48 [9%] other races; and 122 [24%] Hispanic or Latino ethnicity). During a median follow-up period of 27 days (IQR 26-28), 31 (12%) of 256 patients on apixaban had a composite venous thromboembolism compared with 45 (18%) of 256 participants receiving SOC (relative risk [RR] 0·69, 95% CI 0·45-1·05; p=0·080). Two major bleeding events occurred in each group (RR 1·0, 95% CI 0·14-7·01; p=1·0). A higher incidence of CRNM bleeding, primarily grade 1 or 2 epistaxis, occurred in the apixaban group (11 [4%] of 256 participants) compared with the SOC group (3 [1%] of 256; RR 3·67, 95% CI 1·04-12·97, p=0·030). The most frequent grade 3-5 adverse events in both groups were thrombocytopenia (n=28 for the apixaban group and n=20 for the SOC group) or platelet count decreased (n=49 and n=45), anaemia (n=77 and n=74), febrile neutropenia (n=27 and n=20), and neutropenia (n=16 and n=17) or neutrophil count decreased (n=22 and n=25). Five deaths occurred, which were due to infection (n=3 in the SOC group), cardiac arrest (n=1 in apixaban group), and haemorrhagic cerebral sinus vein thrombosis (n=1 in the SOC group). There was one apixaban-related death (coagulopathy and haemorrhage after cardiac arrest of unknown cause).

INTERPRETATION

PREVAPIX-ALL is, to our knowledge, the first trial assessing primary thromboprophylaxis using a direct oral anticoagulant in paediatric patients with acute lymphoblastic leukaemia or lymphoma. No statistically significant treatment benefit was identified in participants receiving apixaban. Major and CRNM bleeding were infrequent overall, but a higher incidence of CRNM bleeding (primarily epistaxis in younger children) occurred in participants receiving apixaban. For patients deemed to be at particularly high risk of thrombosis, PREVAPIX-ALL provides encouraging safety data for the use of apixaban in clinical settings in which the potential benefits are thought to outweigh the risk of bleeding.

FUNDING

Bristol Myers Squibb-Pfizer Alliance.

Neurological Improvement via Lysophosphatidic Acid Administration in a Rodent Model of Cardiac Arrest-Induced Brain Injury

Lysophosphatidic acid (LPA) serves as a fundamental constituent of phospholipids. While prior studies have shown detrimental effects of LPA in a range of pathological conditions, including brain ischemia, no studies have explored the impact of LPA in the context of cardiac arrest (CA). The aim of this study is to evaluate the effects of the intravenous administration of an LPA species containing oleic acid, LPA (18:1) on the neurological function of rats (male, Sprague Dawley) following 8 min of asphyxial CA. Baseline characteristics, including body weight, surgical procedure time, and vital signs before cardiac arrest, were similar between LPA (18:1)-treated (n = 10) and vehicle-treated (n = 10) groups. There was no statistically significant difference in 24 h survival between the two groups. However, LPA (18:1)-treated rats exhibited significantly improved neurological function at 24 h examination (LPA (18:1), 85.4% ± 3.1 vs. vehicle, 74.0% ± 3.3, p = 0.045). This difference was most apparent in the retention of coordination ability in the LPA (18:1) group (LPA (18:1), 71.9% ± 7.4 vs. vehicle, 25.0% ± 9.1, p < 0.001). Overall, LPA (18:1) administration in post-cardiac arrest rats significantly improved neurological function, especially coordination ability at 24 h after cardiac arrest. LPA (18:1) has the potential to serve as a novel therapeutic in cardiac arrest.

Prophylactic supplement with melatonin prevented the brain injury after cardiac arrest in rats

Prophylactic pharmacotherapy for health care in patients with high risk of cardiac arrest (CA) is an elusive and less explored strategy. Melatonin has possibilities used as a daily nutraceutical to trigger the cellular adaptation. We sought to find the effects of long-term daily prophylactic supplement with melatonin on the victim of CA. Rats were divided into sham, CA, and melatonin + CA (Mel + CA) groups. The rats in the Mel + CA group received daily IP injection of melatonin 100 mg/kg for 14 days. CA was induced by 8 min asphyxia and followed by manual cardiopulmonary resuscitation. The endpoint was 24 h after resuscitation. Survival, neurological outcome, and hippocampal mitochondrial integrity, dynamics and function were assessed. Survival was significantly higher in the Mel + CA group than the CA group (81 vs. 42%, P = 0.04). Compared to the CA group, neurological damage in the CA1 region and the level of cytochrome c, cleaved caspase-3 and caspase-9 in the Mel + CA group were decreased (P < 0.05). Mitochondrial function and integrity were protected in the Mel + CA group compared to the CA group, according to the results of mitochondrial swelling, ΔΨm, ROS production, oxygen consumption rate, and respiratory control rate (P < 0.05). Melatonin increased SIRT3 and downregulated acetylated CypD. The mitochondrial dynamics and autophagy were improved in the Mel + CA group (P < 0.05). Long-term daily prophylactic supplement with melatonin buy the time from brain injury after CA.

Changes in vital signs during adrenaline administration for hemostasis in intracordal injection: an observational study with a hypothetical design of endotracheal adrenaline administration in cardiopulmonary arrest

BACKGROUND

The background is that intravenous adrenaline administration is recommended for advanced cardiovascular life support in adults and endotracheal administration is given low priority. The reason is that the optimal dose of adrenaline in endotracheal administration is unknown, and it is ethically difficult to design studies of endotracheal adrenaline administration with non-cardiopulmonary arrest. We otolaryngologists think so because we administered adrenaline to the vocal folds for hemostasis after intracordal injection under local anesthesia, but have had few cases of vital changes. We hypothesized that examining vital signs before and after adrenaline administration for hemostasis would help determine the optimal dose of endotracheal adrenaline.

METHODS

We retrospectively examined the medical records of 79 patients who visited our hospital from January 2018 to December 2020 and received adrenaline in the vocal folds and trachea for hemostasis by intracordal injection under local anesthesia to investigate changes in heart rate and systolic blood pressure before and after the injection.

RESULTS

The mean heart rates before and after injection were 83.96 ± 18.51 (standard deviation) beats per minute (bpm) and 81.50 ± 15.38 (standard deviation) bpm, respectively. The mean systolic blood pressure before and after the injection were 138.13 ± 25.33 (standard deviation) mmHg and 135.72 ± 22.19 (standard deviation) mmHg, respectively. Heart rate and systolic blood pressure had P-values of 0.136, and 0.450, respectively, indicating no significant differences.

CONCLUSIONS

Although this study was an observational, changes in vital signs were investigated assuming endotracheal adrenaline administration. The current recommended dose of adrenaline in endotracheal administration with cardiopulmonary arrest may not be effective. In some cases of cardiopulmonary arrest, intravenous and intraosseous routes of adrenaline administration may be difficult and the opportunity for resuscitation may be missed. Therefore, it is desirable to have many options for adrenaline administration. Therefore, if the optimal dose and efficacy of endotracheal adrenaline administration can be clarified, early adrenaline administration will be possible, which will improve return of spontaneous circulation (ROSC) and survival discharge rates.

Assessment of the Effects of Sodium Nitroprusside Administered Via Intracranial Subdural Catheters on the Cerebral Blood Flow and Lactate Using Dynamic Susceptibility Contrast Magnetic Resonance Imaging and Proton Magnetic Resonance Spectroscopy in a Pig Cardiac Arrest Model

Background Cerebral blood flow (CBF) is impaired in the early phase after return of spontaneous circulation. Sodium nitroprusside (SNP) administration via intracranial subdural catheters improves cerebral cortical microcirculation. We determined whether the SNP treatment improves CBF in the subcortical tissue and evaluated the effects of this treatment on cerebral lactate. Methods and Results Sixty minutes after return of spontaneous circulation following 14 minutes of untreated cardiac arrest, 14 minipigs randomly received 4 mg SNP or saline via intracranial subdural catheters. CBF was measured in regions of interest within the cerebrum and thalamus using dynamic susceptibility contrast-magnetic resonance imaging. After return of spontaneous circulation, CBF was expressed as a percentage of the baseline value. In the saline group, the %CBF in the regions of interest within the cerebrum remained at approximately 50% until 3.5 hours after return of spontaneous circulation, whereas %CBF in the thalamic regions of interest recovered to approximately 73% at this time point. The percentages of the baseline values in the cortical gray matter and subcortical white matter were higher in the SNP group (group effect P=0.026 and 0.025, respectively) but not in the thalamus. The cerebral lactate/creatine ratio measured using magnetic resonance spectroscopy increased over time in the saline group but not in the SNP group (group-time interaction P=0.035). The thalamic lactate/creatine ratio was similar in the 2 groups. Conclusions SNP administered via intracranial subdural catheters improved CBF not only in the cortical gray matter but also in the subcortical white matter. The CBF improvement by SNP was accompanied by a decrease in cerebral lactate.

Neuroprotection of NSC Therapy is Superior to Glibenclamide in Cardiac Arrest-Induced Brain Injury via Neuroinflammation Regulation

Cardiac arrest (CA) is common and devastating, and neuroprotective therapies for brain injury after CA remain limited. Neuroinflammation has been a target for two promising but underdeveloped post-CA therapies: neural stem cell (NSC) engrafting and glibenclamide (GBC). It is critical to understand whether one therapy has superior efficacy over the other and to further understand their immunomodulatory mechanisms. In this study, we aimed to evaluate and compare the therapeutic effects of NSC and GBC therapies post-CA. In in vitro studies, BV2 cells underwent oxygen-glucose deprivation (OGD) for three hours and were then treated with GBC or co-cultured with human NSCs (hNSCs). Microglial polarization phenotype and TLR4/NLRP3 inflammatory pathway proteins were detected by immunofluorescence staining. Twenty-four Wistar rats were randomly assigned to three groups (control, GBC, and hNSCs, N = 8/group). After 8 min of asphyxial CA, GBC was injected intraperitoneally or hNSCs were administered intranasally in the treatment groups. Neurological-deficit scores (NDSs) were assessed at 24, 48, and 72 h after return of spontaneous circulation (ROSC). Immunofluorescence was used to track hNSCs and quantitatively evaluate microglial activation subtype and polarization. The expression of TLR4/NLRP3 pathway-related proteins was quantified via Western blot. The in vitro studies showed the highest proportion of activated BV2 cells with an increased expression of TLR4/NLRP3 signaling proteins were found in the OGD group compared to OGD + GBC and OGD + hNSCs groups. NDS showed significant improvement after CA in hNSC and GBC groups compared to controls, and hNSC treatment was superior to GBC treatment. The hNSC group had more inactive morphology and anti-inflammatory phenotype of microglia. The quantified expression of TLR4/NLRP3 pathway-related proteins was significantly suppressed by both treatments, and the suppression was more significant in the hNSC group compared to the GBC group. hNSC and GBC therapy regulate microglial activation and the neuroinflammatory response in the brain after CA through TLR4/NLRP3 signaling and exert multiple neuroprotective effects, including improved neurological function and shortened time of severe neurological deficit. In addition, hNSCs displayed superior inflammatory regulation over GBC.

[Expert consensus for diagnosis and treatment of post-cardiac arrest syndrome in adults by combining traditional Chinese and Western medicine in China (2023)]

Reperfusion injury occurs after return of spontaneous circulation (ROSC) in patients with cardiac arrest (CA), which leads to multiple organ dysfunction, called post-cardiac arrest syndrome (PCAS). PCAS is closely related to the prognosis of CA patients, and is an independent risk factor of survival. Integrated traditional Chinese and Western medicine diagnosis and treatment is critical for improving prognosis of PCAS. In order to guide and standardize integrated traditional Chinese and Western medicine diagnosis and treatment in PCAS among clinicians, nurses and research personnel in China, the Emergency Medicine Professional Committee of the Chinese Society of Integrated Chinese and Western Medicine has established an expert group to determine 14 clinical issues related to the diagnosis and treatment of PCAS with integrated traditional Chinese and Western medicine through clinical survey. The working group formulates a search strategy for each clinical issue according to the PICO principle. Chinese and English literature were searched from CNKI, Wanfang, VIP, SinoMed, PubMed, Embase, and Cochrane Library. The grade of recommendations assessment, development and evaluation (GRADE) were used to form the level of evidence and recommendation. When the literature evidence was insufficient, the recommendations and level of recommendation were formed after expert discussion. Combined with the aspects of generalizability, suitability, and resource utilization, the expert consensus developed 28 recommendations around the 14 aspects of three stages of PCAS, including early circulation, respiratory support and reversible cause relief, mid-term neuroprotection, improvement of coagulation, prevention and treatment of infection, kidney and gastrointestinal protection and blood sugar control, post rehabilitation treatment, providing references for the integrated traditional Chinese and Western medicine of the diagnosis and treatment for PCAS.

Targeted Activation of HNF4α by AMPK Inhibits Apoptosis and Ameliorates Neurological Injury Caused by Cardiac Arrest in Rats

Previous studies have shown that AMPK plays an important role in cerebral ischemia-reperfusion injury by participating in apoptosis, but the exact mechanism and target of action remains unclear. This study aimed to investigate the protective mechanism of AMPK activation on brain injury secondary to cardiac arrest. HE, Nills and TUNEL assays were used to evaluate neuronal damage and apoptosis. The relationships between AMPK, HNF4α and apoptotic genes were verified by ChIP-seq, dual-luciferase and WB assays. The results showed that AMPK improved the 7-day memory function of rats, and reduced neuronal cell injury and apoptosis in the hippocampal CA1 region after ROSC, while the use of HNF4α inhibitor weakened the protective effect of AMPK. Further research found that AMPK positively regulated the expression of HNF4α, and AMPK could promote the expression of Bcl-2 and inhibit the expression of Bax and Cleaved-Caspase 3. In vitro experiments showed that AMPK ameliorated neuronal injury by inhibiting apoptosis through the activation of HNF4α. Combined with ChIP-seq, JASPAR analysis and Dual-luciferase assay, the binding site of HNF4α to the upstream promoter of Bcl-2 was found. Taken together, AMPK attenuates brain injury after CA by activating HNF4α to target Bcl-2 to inhibit apoptosis.

Bicarbonate, calcium, and magnesium for in-hospital cardiac arrest - An instrumental variable analysis

INTRODUCTION

Bicarbonate, calcium, and magnesium are commonly used during in-hospital cardiac arrest. Whether these drugs are associated with survival in cardiac arrest patients is uncertain.

METHODS

This was an observational study using data from the Get With The Guidelines registry. Adult patients with an in-hospital cardiac arrest between January 2008 and December 2021 were included. An instrumental variable approach was used based on hospital preferences for bicarbonate, calcium, and magnesium, respectively. The primary outcome was survival to hospital discharge.

RESULTS

A total of 319,230 patients were included. The median age was 66 years, 59% patients were male, and 85% patients presented with a non-shockable rhythm. Bicarbonate was administered in 58% patients, calcium in 33% patients, and magnesium in 10% patients. When considering drug use in the previous cardiac arrest patient at a given hospital as an instrument, the absolute difference in survival to hospital discharge was estimated at -14.2% (95% CI, -19.9 to -8.6) for bicarbonate, -3.0% (95% CI, -8.6 to 2.6) for calcium, and 10.7% (95% CI, -0.8 to 22.2) for magnesium as compared to no drug. When considering the proportion of drug use within the past year at a given hospital as an instrument, the confidence intervals were very wide, making the results difficult to interpret.

CONCLUSIONS

In this analysis, the results for bicarbonate, calcium, and magnesium were inconclusive due to wide confidence intervals and inconsistencies in estimates across instrumental variables. Randomized trials are needed to investigate the effect of these drugs on patient outcomes.

Nicotinamide restores tissue NAD+ and improves survival in rodent models of cardiac arrest

Metabolic suppression in the ischemic heart is characterized by reduced levels of NAD+ and ATP. Since NAD+ is required for most metabolic processes that generate ATP, we hypothesized that nicotinamide restores ischemic tissue NAD+ and improves cardiac function in cardiomyocytes and isolated hearts, and enhances survival in a mouse model of cardiac arrest. Mouse cardiomyocytes were exposed to 30 min simulated ischemia and 90 min reperfusion. NAD+ content dropped 40% by the end of ischemia compared to pre-ischemia. Treatment with 100 μM nicotinamide (NAM) at the start of reperfusion completely restored the cellular level of NAD+ at 15 min of reperfusion. This rescue of NAD+ depletion was associated with improved contractile recovery as early as 10 min post-reperfusion. In a mouse model of cardiac arrest, 100 mg/kg NAM administered IV immediately after cardiopulmonary resuscitation resulted in 100% survival at 4 h as compared to 50% in the saline group. In an isolated rat heart model, the effect of NAM on cardiac function was measured for 20 min following 18 min global ischemia. Rate pressure product was reduced by 26% in the control group following arrest. Cardiac contractile function was completely recovered with NAM treatment given at the start of reperfusion. NAM restored tissue NAD+ and enhanced production of lactate and ATP, while reducing glucose diversion to sorbitol in the heart. We conclude that NAM can rapidly restore cardiac NAD+ following ischemia and enhance glycolysis and contractile recovery, with improved survival in a mouse model of cardiac arrest.

Opioid Overdose: Limitations in Naloxone Reversal of Respiratory Depression and Prevention of Cardiac Arrest

Opioids are effective analgesics, but they can have harmful adverse effects, such as addiction and potentially fatal respiratory depression. Naloxone is currently the only available treatment for reversing the negative effects of opioids, including respiratory depression. However, the effectiveness of naloxone, particularly after an opioid overdose, varies depending on the pharmacokinetics and the pharmacodynamics of the opioid that was overdosed. Long-acting opioids, and those with a high affinity at the µ-opioid receptor and/or slow receptor dissociation kinetics, are particularly resistant to the effects of naloxone. In this review, the authors examine the pharmacology of naloxone and its safety and limitations in reversing opioid-induced respiratory depression under different circumstances, including its ability to prevent cardiac arrest.

Lack of Association of Initial Vasopressor Dosing with Survival and Cardiac Re-Arrest Likelihood After Return of Spontaneous Circulation

BACKGROUND

Cardiac arrest occurs in approximately 350,000 patients outside the hospital and approximately 30,000 patients in the emergency department (ED) annually in the United States. When return of spontaneous circulation (ROSC) is achieved, hypotension is a common complication. However, optimal dosing of vasopressors is not clear.

OBJECTIVE

The objective of this study was to determine if initial vasopressor dosing was associated with cardiac re-arrest in patients after ROSC.

METHODS

This was a retrospective, single-center analysis of adult patients experiencing cardiac arrest prior to arrival or within the ED. Patients were assigned to one of four groups based on starting dose of vasopressor: low dose (LD; < 0.25 µg/kg/min), medium dose (MD; 0.25-0.49 µg/kg/min), high dose (HD; 0.5-0.99 µg/kg/min), and very high dose (VHD; ≥ 1 µg/kg/min). Data collection was performed primarily via manual chart review of medical records. The primary outcome was incidence of cardiac re-arrest within 1 h of vasopressor initiation. Multivariate logistic regression analysis was conducted to identify any covariates strongly associated with the primary outcome.

RESULTS

No difference in cardiac re-arrest incidence was noted between groups. The VHD group was significantly more likely to require a second vasopressor (p = 0.003). The HD group had lower survival rates to hospital discharge compared with the LD and MD groups (p = 0.0033 and p = 0.0147). In the multivariate regression, longer duration of pre-vasopressor re-arrests and hyperkalemic cardiac arrest etiology were significant predictors of cardiac re-arrest after vasopressor initiation.

CONCLUSIONS

Initial vasopressor dosing was not found to be associated with risk of cardiac re-arrest or, conversely, risk of adverse events.

Is epinephrine still the drug of choice during cardiac arrest in the emergency department of the hospital? A meta-analysis

Epinephrine is the first-line emergency drug for cardiac arrest and anaphylactic reactions but is reported to be associated with many challenges resulting in its under- or improper utilization. Therefore, in this meta-analysis, the efficacy and safety of epinephrine as a first-line cardiac emergency drug for both out-of-hospital and in-hospital patients was assessed. Pertinent articles were searched in central databases like PubMed, Scopus, and Web of Science, using appropriate keywords as per the PRISMA guidelines. Retrospective and prospective studies were included according to the predefined PICOS criteria. RevMan and MedCalc software were used and statistical parameters such as odds ratio and risk ratio were calculated. Twelve clinical trials with a total of 208,690 cardiac arrest patients from 2000 to 2022 were included, in accordance with the chosen inclusion criteria. In the present meta-analysis, a high odds ratio (OR) value of 3.67 (95 % CI 2.32-5.81) with a tau2 value of 0.64, a chi2 value of 12,446.86, df value of 11, I2 value of 100 %, Z-value 5.53, and a p-value < 0.00001 were reported. Similarly, the risk ratio of 1.89 (95 % CI 1.47-2.43) with a tau2 value of 0.19, chi2 value of 11,530.67, df value of 11, I2 value of 100 %, Z-value of 4.95, and p-value < 0.000001. The present meta-analysis strongly prefers epinephrine injection as the first cardiac emergency drug for both out-of-hospital and in-hospital patients during cardiac arrest.

Pathophysiology and treatment of adults with arrhythmias in the emergency department, part 2: Ventricular and bradyarrhythmias

PURPOSE

This is the second article in a 2-part series reviewing the pathophysiology and treatment considerations for arrhythmias. Part 1 of the series discussed aspects related to treating atrial arrhythmias. Here in part 2, the pathophysiology of ventricular arrhythmias and bradyarrhythmias and current evidence on treatment approaches are reviewed.

SUMMARY

Ventricular arrhythmias can arise suddenly and are a common cause of sudden cardiac death. Several antiarrhythmics may be effective in management of ventricular arrhythmias, but there is robust evidence to support the use of only a few of these agents, and such evidence was largely derived from trials involving patients with out-of-hospital cardiac arrest. Bradyarrhythmias range from asymptomatic mild prolongation of nodal conduction to severe conduction delays and impending cardiac arrest. Vasopressors, chronotropes, and pacing strategies require careful attention and titration to minimize adverse effects and patient harm.

CONCLUSION

Ventricular arrhythmias and bradyarrhythmias can be consequential and require acute intervention. As experts in pharmacotherapy, acute care pharmacists can participate in providing high-level intervention by aiding in diagnostic workup and medication selection.

A Review of Bicarbonate Use in Common Clinical Scenarios

BACKGROUND

The use of sodium bicarbonate to treat metabolic acidosis is intuitive, yet data suggest that not all patients benefit from this therapy.

OBJECTIVE

In this narrative review, we describe the physiology behind commonly encountered nontoxicologic causes of metabolic acidosis, highlight potential harm from the indiscriminate administration of sodium bicarbonate in certain scenarios, and provide evidence-based recommendations to assist emergency physicians in the rational use of sodium bicarbonate.

DISCUSSION

Sodium bicarbonate can be administered as a hypertonic push, as a resuscitation fluid, or as an infusion. Lactic acidosis and cardiac arrest are two common scenarios where there is limited benefit to routine use of sodium bicarbonate, although certain circumstances, such as patients with concomitant acute kidney injury and lactic acidosis may benefit from sodium bicarbonate. Patients with cardiac arrest secondary to sodium channel blockade or hyperkalemia also benefit from sodium bicarbonate therapy. Recent data suggest that the use of sodium bicarbonate in diabetic ketoacidosis does not confer improved patient outcomes and may cause harm in pediatric patients. Available evidence suggests that alkalinization of urine in rhabdomyolysis does not improve patient-centered outcomes. Finally, patients with a nongap acidosis benefit from sodium bicarbonate supplementation.

CONCLUSIONS

Empiric use of sodium bicarbonate in patients with nontoxicologic causes of metabolic acidosis is not warranted and likely does not improve patient-centered outcomes, except in select scenarios. Emergency physicians should reserve use of this medication to conditions with clear benefit to patients.

EFFECTS OF M101-AN EXTRACELLULAR HEMOGLOBIN-APPLIED DURING CARDIOPULMONARY RESUSCITATION: AN EXPERIMENTAL RODENT STUDY

ABSTRACT

During and immediately after cardiac arrest, cerebral oxygen delivery is impaired mainly by microthrombi and cerebral vasoconstriction. This may narrow capillaries so much that it might impede the flow of red blood cells and thus oxygen transport. The aim of this proof-of-concept study was to evaluate the effect of M101, an extracellular hemoglobin-based oxygen carrier (Hemarina SA, Morlaix, France) derived from Arenicola marina , applied during cardiac arrest in a rodent model, on markers of brain inflammation, brain damage, and regional cerebral oxygen saturation. Twenty-seven Wistar rats subjected to 6 min of asystolic cardiac arrest were infused M101 (300 mg/kg) or placebo (NaCl 0.9%) concomitantly with start of cardiopulmonary resuscitation. Brain oxygenation and five biomarkers of inflammation and brain damage (from blood, cerebrospinal fluid, and homogenates from four brain regions) were measured 8 h after return of spontaneous circulation. In these 21 different measurements, M101-treated animals were not significantly different from controls except for phospho-tau only in single cerebellum regions ( P = 0.048; ANOVA of all brain regions: P = 0.004). Arterial blood pressure increased significantly only at 4 to 8 min after return of spontaneous circulation ( P < 0.001) and acidosis decreased ( P = 0.009). While M101 applied during cardiac arrest did not significantly change inflammation or brain oxygenation, the data suggest cerebral damage reduction due to hypoxic brain injury, measured by phospho-tau. Global burden of ischemia appeared reduced because acidosis was less severe. Whether postcardiac arrest infusion of M101 improves brain oxygenation is unknown and needs to be investigated.

Short-Acting Neuromuscular Blockade Improves Inter-rater Reliability of Median Somatosensory Evoked Potentials in Post-cardiac arrest Prognostication

BACKGROUND

Although median nerve somatosensory evoked potentials are routinely used for prognostication in comatose cardiac arrest survivors, myogenic artifact can reduce inter-rater reliability, leading to unreliable or inaccurate results. To minimize this risk, we determined the benefit of neuromuscular blockade agents in improving the inter-rater reliability and signal-to-noise ratio of SSEPs in the context of prognostication.

METHODS

Thirty comatose survivors of cardiac arrest were enrolled in the study, following the request from an intensivist to complete an SSEP for prognostication. Right and left median nerve SSEPs were obtained from each patient, before and after administration of an NMB agent. Clinical histories and outcomes were retrospectively reviewed. The SSEP recordings before and after NMB were randomized and reviewed by five blinded raters, who assessed the latency and amplitude of cortical and noncortical potentials (vs. absence of response) as well as the diagnostic quality of cortical recordings. The inter-rater reliability of SSEP interpretation before and after NMB was compared via Fleiss' κ score.

RESULTS

Following NMB administration, Fleiss' κ score for cortical SSEP interpretation significantly improved from 0.37 to 0.60, corresponding to greater agreement among raters. The raters were also less likely to report the cortical recordings as nondiagnostic following NMB (40.7% nondiagnostic SSEPs pre-NMB; 17% post-NMB). The SNR significantly improved following NMB, especially when the pre-NMB SNR was low (< 10 dB). Across the raters, there were three patients whose SSEP interpretation changed from bilaterally absent to bilaterally present after NMB was administered (potential false positives without NMB).

CONCLUSIONS

NMB significantly improves the inter-rater reliability and SNR of median SSEPs for prognostication among comatose cardiac arrest survivors. To ensure the most reliable prognostic information in comatose post-cardiac arrest survivors, pharmacologic paralysis should be consistently used before recording SSEPs.

Comparison the efficacy of amiodarone and lidocaine for cardiac arrest: A network meta-analysis

BACKGROUND

There is no evidence that antiarrhythmic drugs can improve long-term survival or survival with favorable neurological outcomes in cardiac arrest patients. We did this network meta-analysis to comprehensively compare the efficacy of various antiarrhythmic drugs for cardiac arrest patients.

METHODS

We searched studies from inception until Nov 11, 2022 through PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), VIP Database, and Wanfang database. All studies comparing different antiarrhythmic drugs for cardiac arrest were included in this meta-analysis. Outcomes were survival to hospital discharge in cardiac arrest, survival to hospital admission/24 h and favorable neurological outcome. This network meta-analysis was performed by R software.

RESULTS

Finally, a total of 9 studies (10,980 patients) were finally included in this network meta-analysis. Amiodarone (odd ratio [OR] 2.28, 95% credibility interval [CrI] 1.61-3.27) and lidocaine (OR 1.53, 95% CrI 1.05-2.25) was superior than placebo in terms of the survival to hospital admission/24 h with statistically significant. Amiodarone (OR 2.19, 95% CrI 1.54-3.14) and lidocaine (OR 1.58, 95% CrI 1.09-2.32) was superior than placebo in terms of the survival to hospital discharge with statistically significant. Amiodarone (OR 2.43, 95% CrI 1.61-3.68) and lidocaine (OR 1.62, 95% CrI 1.04-2.53) was superior than placebo in terms of the favorable neurological outcome with statistically significant. The surface under the cumulative ranking (SUCRA) shows that amiodarone ranked first (SUCRA, 99.6%), lidocaine ranked second (SUCRA, 49.6%), placebo ranked the last (SUCRA, 0.86%). Inverted funnel plot is essentially symmetrical, it is possible that this study has a small sample effect or a small publication bias.

CONCLUSIONS

Amiodarone had the best effect on both survival to hospital admission, discharge and more favorable neurological outcome. Thus, amiodarone should be listed as first line drug for cardiac arrest. However, the quality of available evidence limits the formation of powerful conclusions regarding the comparative efficacy or safety of amiodarone or lidocaine used to treat cardiac arrest. Higher-quality randomized controlled trials are required for further research in future.

Thiamine for the Treatment of Cardiac Arrest-Induced Neurological Injury: A Randomized, Blinded, Placebo-Controlled Experimental Study

Background Thiamine supplementation has demonstrated protective effects in a mouse model of cardiac arrest. The aim of this study was to investigate the neuroprotective effects of thiamine in a clinically relevant large animal cardiac arrest model. The hypothesis was that thiamine reduces neurological injury evaluated by neuron-specific enolase levels. Methods and Results Pigs underwent myocardial infarction and subsequently 9 minutes of untreated cardiac arrest. Twenty minutes after successful resuscitation, the pigs were randomized to treatment with either thiamine or placebo. All pigs underwent 40 hours of intensive care and were awakened for assessment of functional neurological outcome up until 9 days after cardiac arrest. Nine pigs were included in both groups, with 8 in each group surviving the entire intensive care phase. Mean area under the curve for neuron-specific enolase was similar between groups, with 81.5 μg/L per hour (SD, 20.4) in the thiamine group and 80.5 μg/L per hour (SD, 18.3) in the placebo group, with an absolute difference of 1.0 (95% CI, -57.8 to 59.8; P=0.97). Likewise, there were no absolute difference in neurological deficit score at the end of the protocol (2 [95% CI, -38 to 42]; P=0.93). There was no absolute mean group difference in lactate during the intensive care period (1.1 mmol/L [95% CI, -0.5 to 2.7]; P=0.16). Conclusions In this randomized, blinded, placebo-controlled trial using a pig cardiac arrest model with myocardial infarction and long intensive care and observation for 9 days, thiamine showed no effect in changes to functional neurological outcome or serum levels of neuron-specific enolase. Thiamine treatment had no effect on lactate levels after successful resuscitation.

A Nanotherapy of Octanoic Acid Ameliorates Cardiac Arrest/Cardiopulmonary Resuscitation-Induced Brain Injury via RVG29- and Neutrophil Membrane-Mediated Injury Relay Targeting

Treatment of cardiac arrest/cardiopulmonary resuscitation (CA/CPR)-induced brain injury remains a challenging issue without viable therapeutic options. Octanoic acid (OA), a lipid oil that is mainly metabolized in the astrocytes of the brain, is a promising treatment for this type of injury owing to its potential functions against oxidative stress, apoptosis, inflammation, and ability to stabilize mitochondria. However, the application of OA is strictly limited by its short half-life and low available concentration in the target organ. Herein, based on our previous research, an OA-based nanotherapy coated with a neutrophil membrane highly expressing RVG29, RVG29-H-NP_OA, was successfully constructed by computer simulation-guided supramolecular assembly of polyethylenimine and OA. The in vitro and in vivo experiments showed that RVG29-H-NP_OA could target and be distributed in the injured brain focus via the relay-targeted delivery mediated by RVG29-induced blood-brain barrier (BBB) penetration and neutrophil membrane protein-induced BBB binding and injury targeting. This results in enhancements of the antioxidant, antiapoptotic, mitochondrial stability-promoting and anti-inflammatory effects of OA and exhibited systematic alleviation of astrocyte injury, neuronal damage, and inflammatory response in the brain. Due to their systematic intervention in multiple pathological processes, RVG29-H-NP_OA significantly increased the 24 h survival rate of CA/CPR model rats from 40% to 100% and significantly improved their neurological functions. Thus, RVG29-H-NP_OA are expected to be a promising therapeutic for the treatment of CA/CPR-induced brain injury.

Epinephrine vs placebo in neonatal resuscitation: ROSC and brain MRS/MRI in term piglets

BACKGROUND

We aimed to investigate the effect of epinephrine vs placebo on return of spontaneous circulation (ROSC) and brain magnetic resonance spectroscopy and imaging (MRS/MRI) in newborn piglets with hypoxic cardiac arrest (CA).

METHODS

Twenty-five piglets underwent hypoxia induced by endotracheal tube clamping until CA. The animals were randomized to CPR + intravenous epinephrine or CPR + placebo (normal saline). The primary outcome was ROSC, and secondary outcomes included time-to-ROSC, brain MRS/MRI, and composite endpoint of death or severe brain MRS/MRI abnormality.

RESULTS

ROSC was more frequent in animals treated with epinephrine than placebo; 10/13 vs 4/12, RR = 2.31 (95% CI: 1.09-5.77). We found no difference in time-to-ROSC (120 (113-211) vs 153 (116-503) seconds, p = 0.7) or 6-h survival (7/13 vs 3/12, p = 0.2). Among survivors, there was no difference between groups in brain MRS/MRI. We found no difference in the composite endpoint of death or severe brain MRS/MRI abnormality; RR = 0.7 (95% CI: 0.37-1.19).

CONCLUSIONS

Resuscitation with epinephrine compared to placebo improved ROSC frequency after hypoxic CA in newborn piglets. We found no difference in time-to-ROSC or the composite endpoint of death or severe brain MRS/MRI abnormality.

IMPACT

In a newborn piglet model of hypoxic cardiac arrest, resuscitation with epinephrine compared to placebo improved the rate of return of spontaneous circulation and more than doubled the 6-h survival. Brain MRS/MRI biomarkers were used to evaluate the effect of epinephrine vs placebo. We found no difference between groups in the composite endpoint of death or severe brain MRS/MRI abnormality. This study adds to the limited evidence regarding the effect and safety of epinephrine; the lack of high-quality evidence from randomized clinical trials was highlighted in the latest ILCOR 2020 guidelines, and newborn animal studies were specifically requested.

Post-cardiac arrest Sedation Promotes Electroencephalographic Slow-wave Activity and Improves Survival in a Mouse Model of Cardiac Arrest

BACKGROUND

Patients resuscitated from cardiac arrest are routinely sedated during targeted temperature management, while the effects of sedation on cerebral physiology and outcomes after cardiac arrest remain to be determined. The authors hypothesized that sedation would improve survival and neurologic outcomes in mice after cardiac arrest.

METHODS

Adult C57BL/6J mice of both sexes were subjected to potassium chloride-induced cardiac arrest and cardiopulmonary resuscitation. Starting at the return of spontaneous circulation or at 60 min after return of spontaneous circulation, mice received intravenous infusion of propofol at 40 mg · kg-1 · h-1, dexmedetomidine at 1 µg · kg-1 · h-1, or normal saline for 2 h. Body temperature was lowered and maintained at 33°C during sedation. Cerebral blood flow was measured for 4 h postresuscitation. Telemetric electroencephalogram (EEG) was recorded in freely moving mice from 3 days before up to 7 days after cardiac arrest.

RESULTS

Sedation with propofol or dexmedetomidine starting at return of spontaneous circulation improved survival in hypothermia-treated mice (propofol [13 of 16, 81%] vs. no sedation [4 of 16, 25%], P = 0.008; dexmedetomidine [14 of 16, 88%] vs. no sedation [4 of 16, 25%], P = 0.002). Mice receiving no sedation exhibited cerebral hyperemia immediately after resuscitation and EEG power remained less than 30% of the baseline in the first 6 h postresuscitation. Administration of propofol or dexmedetomidine starting at return of spontaneous circulation attenuated cerebral hyperemia and increased EEG slow oscillation power during and early after sedation (40 to 80% of the baseline). In contrast, delayed sedation failed to improve outcomes, without attenuating cerebral hyperemia and inducing slow-wave activity.

CONCLUSIONS

Early administration of sedation with propofol or dexmedetomidine improved survival and neurologic outcomes in mice resuscitated from cardiac arrest and treated with hypothermia. The beneficial effects of sedation were accompanied by attenuation of the cerebral hyperemic response and enhancement of electroencephalographic slow-wave activity.

EDITOR’S PERSPECTIVE

No Code-The Role of Sodium Bicarbonate and Naloxone in Neonatal Resuscitation

Resuscitations in neonates and infants present caregivers with challenging decisions in a highly stressful environment. Consideration of the pathophysiology of cardiac arrest and respiratory failure prior to an emergency allows for thoughtful utilization of pharmacotherapy. It is vital to remember that establishment of an airway and delivery of breaths and chest compressions should be prioritized. Epinephrine is first-line pharmacotherapy for severe bradycardia or cardiac arrest unresponsive to the provision of respiratory support and chest compressions. Sodium bicarbonate may be considered based on the intrinsic links between cardiac arrest, respiratory failure, and mixed acidosis. However, experimental and clinical data suggest that sodium bicarbonate worsens myocardial performance by several mechanisms (decreased intramyocardial pH, reduced oxygen delivery to tissues, reduced coronary perfusion pressure). Additionally, rapid administration of this hyperosmolar therapy may contribute to intracranial hemorrhage. With no clear benefit and multiple risks, sodium bicarbonate has been excluded from neonatal resuscitation algorithms. Opioids may produce respiratory depression in neonates, whether given to the mother prior to delivery or in neonatal intensive care; therefore, naloxone may be considered to restore respiratory drive. However, 50 years of neonatal utilization has not produced clinical studies documenting efficacy and safety. On the contrary, clinical studies fail to detect clear benefit and numerous concerning adverse reactions have been reported, including acute withdrawal, cardiorespiratory decompensation, and death. For these reasons, naloxone has also been removed from neonatal resuscitation algorithms. Clear understanding of pathophysiology, pharmacology, and clinical data support the use of multiple pharmacotherapies in neonatal resuscitation, including epinephrine, normal saline, intravenous glucose, adenosine, and calcium gluconate as reviewed in a previous column. The same pathways inform confident exclusion of sodium bicarbonate and naloxone.

Postconditioning by Delayed Administration of Ciclosporin A: Implication for Donation after Circulatory Death (DCD)

Heart transplantation is facing a shortage of grafts. Donation after Circulatory Death (DCD) would constitute a new potential of available organs. In the present work, we aimed to evaluate whether Postconditioning (ischemic or with ciclosporin-A (CsA)) could reduce ischemia-reperfusion injury in a cardiac arrest model when applied at the start of reperfusion or after a delay. An isolated rat heart model was used as a model of DCD. Hearts were submitted to a cardiac arrest of 40 min of global warm ischemia (37 °C) followed by 3 h of 4 °C-cold preservation, then 60 min reperfusion. Hearts were randomly allocated into the following groups: control, ischemic postconditioning (POST, consisting of two episodes each of 30 s ischemia and 30 s reperfusion at the onset of reperfusion), and CsA group (CsA was perfused at 250 nM for 10 min at reperfusion). In respective subgroups, POST and CsA were applied after a delay of 3, 10, and 20 min. Necrosis was lower in CsA and POST versus controls (p < 0.01) whereas heart functions were improved (p < 0.01). However, while the POST lost its efficacy if delayed beyond 3 min of reperfusion, CsA treatment surprisingly showed a reduction of necrosis even if applied after a delay of 3 and 10 min of reperfusion (p < 0.01). This cardioprotection by delayed CsA application correlated with better functional recovery and higher mitochondrial respiratory index. Furthermore, calcium overload necessary to induce mitochondrial permeability transition pore (MPTP) opening was similar in all cardioprotection groups, suggesting a crucial role of MPTP in this delayed protection of DCD hearts.

Sodium Bicarbonate Use During Pediatric Cardiopulmonary Resuscitation: A Secondary Analysis of the ICU-RESUScitation Project Trial

OBJECTIVES

To evaluate associations between sodium bicarbonate use and outcomes during pediatric in-hospital cardiac arrest (p-IHCA).

DESIGN

Prespecified secondary analysis of a prospective, multicenter cluster randomized interventional trial.

SETTING

Eighteen participating ICUs of the ICU-RESUScitation Project (NCT02837497).

PATIENTS

Children less than or equal to 18 years old and greater than or equal to 37 weeks post conceptual age who received chest compressions of any duration from October 2016 to March 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Child and event characteristics, prearrest laboratory values (2-6 hr prior to p-IHCA), pre- and intraarrest hemodynamics, and outcomes were collected. In a propensity score weighted cohort, the relationships between sodium bicarbonate use and outcomes were assessed. The primary outcome was survival to hospital discharge. Secondary outcomes included return of spontaneous circulation (ROSC) and survival to hospital discharge with favorable neurologic outcome. Of 1,100 index cardiopulmonary resuscitation events, median age was 0.63 years (interquartile range, 0.19-3.81 yr); 528 (48.0%) received sodium bicarbonate; 773 (70.3%) achieved ROSC; 642 (58.4%) survived to hospital discharge; and 596 (54.2%) survived to hospital discharge with favorable neurologic outcome. Among the weighted cohort, sodium bicarbonate use was associated with lower survival to hospital discharge rate (adjusted odds ratio [aOR], 0.7; 95% CI, 0.54-0.92; p = 0.01) and lower survival to hospital discharge with favorable neurologic outcome rate (aOR, 0.69; 95% CI, 0.53-0.91; p = 0.007). Sodium bicarbonate use was not associated with ROSC (aOR, 0.91; 95% CI, 0.62-1.34; p = 0.621).

CONCLUSIONS

In this propensity weighted multicenter cohort study of p-IHCA, sodium bicarbonate use was common and associated with lower rates of survival to hospital discharge.

Development of a Translational Model to Assess the Impact of Opioid Overdose and Naloxone Dosing on Respiratory Depression and Cardiac Arrest

In response to a surge of deaths from synthetic opioid overdoses, there have been increased efforts to distribute naloxone products in community settings. Prior research has assessed the effectiveness of naloxone in the hospital setting; however, it is challenging to assess naloxone dosing regimens in the community/first-responder setting, including reversal of respiratory depression effects of fentanyl and its derivatives (fentanyls). Here, we describe the development and validation of a mechanistic model that combines opioid mu receptor binding kinetics, opioid agonist and antagonist pharmacokinetics, and human respiratory and circulatory physiology, to evaluate naloxone dosing to reverse respiratory depression. Validation supports our model, which can quantitatively predict displacement of opioids by naloxone from opioid mu receptors in vitro, hypoxia-induced cardiac arrest in vivo, and opioid-induced respiratory depression in humans from different fentanyls. After validation, overdose simulations were performed with fentanyl and carfentanil followed by administration of different intramuscular naloxone products. Carfentanil induced more cardiac arrest events and was more difficult to reverse than fentanyl. Opioid receptor binding data indicated that carfentanil has substantially slower dissociation kinetics from the opioid receptor compared to 9 other fentanyls tested, which likely contributes to the difficulty in reversing carfentanil. Administration of the same dose of naloxone intramuscularly from 2 different naloxone products with different formulations resulted in differences in the number of virtual patients experiencing cardiac arrest. This work provides a robust framework to evaluate dosing regimens of opioid receptor antagonists to reverse opioid-induced respiratory depression, including those caused by newly emerging synthetic opioids.

Short-Term Treatment with Empagliflozin Resulted in Dehydration and Cardiac Arrest in an Elderly Patient with Specific Complications: A Case Report and Literature Review

Empagliflozin is a sodium-glucose cotransporter-2 inhibitor widely used in the treatment of diabetes mellitus and heart failure. Our case study involved a 68-year-old patient who was admitted to the hospital because of a cerebral infarction. The patient was simultaneously diagnosed with diabetes mellitus and heart failure, for which empagliflozin was initiated. However, food and fluid intake were reduced due to poor appetite. In addition to the side effects of empagliflozin, the patient developed severe dehydration and cardiac arrest. Careful assessment of dehydration and preventive water intake is recommended in elderly patients and those with neurological deficits, especially when receiving empagliflozin.

Inhibition of Nitrosative Stress Attenuates Myocardial Injury and Improves Outcomes after Cardiac Arrest and Resuscitation

OBJECTIVES

Nitrosative stress is widely involved in cell injury via inducing the nitration modification of a variety of proteins. This study aimed to investigate whether inhibition of nitrosative stress attenuated myocardial injury and improved outcomes in a rat model of cardiac arrest (CA) and cardiopulmonary resuscitation (CPR).

METHODS

Adult male Wistar rats were subjected to asphyxia-induced cardiac arrest and subsequently resuscitation. One minute after return of spontaneous circulation (ROSC), rats were randomized and administered the nitrosative stress inhibitor, FeTMPyP (1 or 3 mg/kg), or normal saline as a placebo. 3-Nitrotyrosine (3-NT), mean arterial pressure (MAP), heart rate (HR), mortality, electrocardiogram (ECG), left ventricular ejection fraction (EF) and fractional shortening (FS), and levels of myocardial apoptosis were evaluated. The concentrations of lactate, creatine kinase MB isoenzyme (CK-MB), and angiotensin II (Ang II), were measured in blood samples.

RESULTS

3-NT level was significantly increased in the heart after ROSC. Administration of FeTMPyP (1 or 3 mg/kg) attenuated the increase of 3-NT in the myocardium. Inhibition of nitrosative stress improved survival and attenuated CA/CPR-induced reperfusion injury by maintaining the stability of MAP and HR, and reducing the accumulation of lactic acid. Post-cardiac arrest rats had higher serum CK-MB and Ang II than healthy rats, while EF and FS were lower in healthy rats. Inhibition of nitrosative stress not only alleviated ischemic heart injury but also reduced the occurrence of CA/CPR-induced of arrhythmias. Moreover, nitrosative stress mediated the upregulation of Cleaved caspase-3 and downregulation Bcl-2, which was abolished by FeTMPyP.

CONCLUSIONS

Inhibition of nitrosative stress is a novel molecular target to alleviate myocardial injury and improve outcomes in a rat model of CA/CPR.

Establishing a multicenter, preclinical consortium in resuscitation: A pilot experimental trial evaluating epinephrine in cardiac arrest

BACKGROUND

Large animal studies are an important step in the translation pathway, but single laboratory experiments do not replicate the variability in patient populations. Our objective was to demonstrate the feasibility of performing a multicenter, preclinical, randomized, double-blinded, placebo-controlled cardiac arrest trial. We evaluated the effect of epinephrine on coronary perfusion pressure (CPP) as previous single laboratory studies have reported mixed results.

METHODS

Forty-five swine from 5 different laboratories (Ann Arbor, MI; Baltimore, MD; Los Angeles, CA; Pittsburgh, PA; Toronto, ON) using a standard treatment protocol. Ventricular fibrillation was induced and left untreated for 6 min before starting continuous cardiopulmonary resuscitation (CPR). After 2 min of CPR, 9 animals from each lab were randomized to 1 of 3 interventions given over 12 minutes: (1) Continuous IV epinephrine infusion (0.00375 mg/kg/min) with placebo IV normal saline (NS) boluses every 4 min, (2) Continuous placebo IV NS infusion with IV epinephrine boluses (0.015 mg/kg) every 4 min or (3) Placebo IV NS for both infusion and boluses. The primary outcome was mean CPP during the 12 mins of drug therapy.

RESULTS

There were no significant differences in mean CPP between the three groups: 14.4 ± 6.8 mmHg (epinephrine Infusion), 16.9 ± 5.9 mmHg (epinephrine bolus), and 14.4 ± 5.5 mmHg (placebo) (p = NS). Sensitivity analysis demonstrated inter-laboratory variability in the magnitude of the treatment effect (p = 0.004).

CONCLUSION

This study demonstrated the feasibility of performing a multicenter, preclinical, randomized, double-blinded cardiac arrest trials. Standard dose epinephrine by bolus or continuous infusion did not increase coronary perfusion pressure during CPR when compared to placebo.

Whole Blood Selective Aortic Arch Perfusion for Exsanguination Cardiac Arrest: Assessing Myocardial Tolerance to the Duration of Cardiac Arrest

INTRODUCTION

Selective aortic arch perfusion (SAAP) is an endovascular technique that consists of aortic occlusion with perfusion of the coronary and cerebral circulation. It been shown to facilitate return of spontaneous circulation (ROSC) after exanguination cardiac arrest (ECA), but it is not known how long arrest may last before the myocardium can no longer be durably recovered. The aim of this study is to assess the myocardial tolerance to exsanguination cardiac arrest before successful ROSC with SAAP.

METHODS

Male adult swine (n = 24) were anesthetized, instrumented, and hemorrhaged to arrest. Animals were randomized into three groups: 5, 10, and 15 min of cardiac arrest before resuscitation with SAAP. Following ROSC, animals were observed for 60 min in a critical care environment. Primary outcomes were ROSC, and survival at 1-h post-ROSC.

RESULTS

Shorter cardiac arrest time was associated with higher ROSC rate and better 1-h survival. ROSC was obtained for 100% (8/8) of the 5-min ECA group, 75% (6/8) of the 10-min group, 43% (3/7) of the 15-min group (P = 0.04). One-hour post-ROSC survival was 75%, 50%, and 14% in 5-, 10-, and 15-min groups, respectively (P = 0.02). One-hour survivors in the 5-min group required less norepinephrine (1.31 mg ± 0.83 mg) compared with 10-SAAP (0.76 mg ± 0.24 mg), P = 0.008.

CONCLUSION

Whole blood SAAP can accomplish ROSC at high rates even after 10 min of unsupported cardiac arrest secondary to hemorrhage, with some viability beyond to 15 min. This is promising as a tool for ECA, but requires additional optimization and clinical trials.Animal Use Protocol, IACUC: 0919015.

Tibial Intraosseous Administration of Epinephrine Is Effective in Restoring Return of Spontaneous Circulation in a Pediatric Normovolemic But Not Hypovolemic Cardiac Arrest Model

OBJECTIVE

We compared the efficacy of tibial intraosseous (TIO) administration of epinephrine in a pediatric normovolemic versus hypovolemic cardiac arrest model to determine the incidence of return of spontaneous circulation (ROSC) and plasma epinephrine concentrations over time.

METHODS

This experimental study evaluated the pharmacokinetics of epinephrine and/or incidence of ROSC after TIO administration in either a normovolemic or hypovolemic pediatric swine model.

RESULTS

All subjects in the TIO normovolemia cardiac arrest group experienced ROSC after TIO administration of epinephrine. In contrast, subjects experiencing hypovolemia and cardiac arrest were significantly less likely to experience ROSC when epinephrine was administered TIO versus intravenous (TIO hypovolemia: 14% [1/7] vs IV hypovolemia: 71% [5/7]; P = 0.031). The TIO hypovolemia group exhibited significantly lower plasma epinephrine concentrations versus IV hypovolemia at 60, 90, 120, and 150 seconds (P < 0.05). Although the maximum concentration of plasma epinephrine was similar, the TIO hypovolemia group exhibited significantly slower time to maximum concentration times versus TIO normovolemia subjects (P = 0.004).

CONCLUSIONS

Tibial intraosseous administration of epinephrine reliably facilitated ROSC among normovolemic cardiac arrest pediatric patients, which is consistent with published reports. However, TIO administration of epinephrine was ineffective in restoring ROSC among subjects experiencing hypovolemia and cardiac arrest. Tibial intraosseous-administered epinephrine during hypovolemia and cardiac arrest may have resulted in a potential sequestration of epinephrine in the tibia. Central or peripheral intravascular access attempts should not be abandoned after successful TIO placement in the resuscitation of patients experiencing concurrent hypovolemia and cardiac arrest.

Vasopressin and glucocorticoids for in-hospital cardiac arrest: A systematic review and meta-analysis of individual participant data

AIM

To perform a systematic review and individual participant data meta-analysis of vasopressin and glucocorticoids for the treatment of cardiac arrest.

METHODS

The PRISMA-IPD guidelines were followed. We searched Medline, Embase, and the Cochrane Library for randomized trials comparing vasopressin and glucocorticoids to placebo during cardiac arrest. The population included adults with cardiac arrest in any setting. Pairs of investigators reviewed studies for relevance, extracted data, and assessed risk of bias. Meta-analyses were conducted using individual participant data. A Bayesian framework was used to estimate posterior treatment effects assuming various prior beliefs. The certainty of evidence was evaluated using GRADE.

RESULTS

Three trials were identified including adult in-hospital cardiac arrests only. Individual participant data were obtained from all trials yielding a total of 869 patients. There was some heterogeneity in post-cardiac arrest interventions between the trials. The results favored vasopressin and glucocorticoids for return of spontaneous circulation (odds ratio: 2.09, 95%CI: 1.54 to 2.84, moderate certainty). Estimates for survival at discharge (odds ratio: 1.39, 95%CI: 0.90 to 2.14, low certainty) and favorable neurological outcome (odds ratio: 1.64, 95%CI, 0.99 to 2.72, low certainty) were more uncertain. The Bayesian estimates for return of spontaneous circulation were consistent with the primary analyses, whereas the estimates for survival at discharge and favorable neurological outcome were more dependent on the prior belief.

CONCLUSIONS

Among adults with in-hospital cardiac arrest, vasopressin and glucocorticoids compared to placebo, improved return of spontaneous circulation. Larger trials are needed to determine whether there is an effect on longer-term outcomes.

Review of novel therapeutics in cardiac arrest (ReNTICA): systematic review protocol

INTRODUCTION

Cardiac arrest remains a common and devastating cause of death and disability worldwide. While targeted temperature management has become standard of care to improve functional neurologic outcome, few pharmacologic interventions have shown similar promise.

METHODS/ANALYSIS

This systematic review will focus on prospective human studies from 2015 to 2020 available in PubMed, Web of Science and EMBASE with a primary focus on impact on functional neurologic outcome. Prospective studies that include pharmacologic agents given during or after cardiac arrest will be included. Study selection will be in keeping with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. If sufficient data involving a given agent are available, a meta-analysis will be conducted and compared with current evidence for therapies recommended in international practice guidelines.

ETHICS AND DISSEMINATION

Formal ethical approval will not be required as primary data will not be collected. The results will be disseminated through peer-reviewed publication, conference presentation and lay press.

PROSPERO REGISTRATION NUMBER

International Prospective Register for Systematic Reviews (CRD42021230216).

Humerus Intraosseous and Intravenous Administration of Epinephrine in Normovolemic and Hypovolemic Cardiac Arrest Porcine Models

OBJECTIVE

The aim of this study was to compare area under the curve (AUC), frequency, and odds of return of spontaneous circulation (ROSC) when epinephrine was administered in hypovolemic and normovolemic cardiac arrest models.

METHODS

Twenty-eight adult swine were randomly assigned to 4 groups: HIO Normovolemia Group (HIONG); HIO Hypovolemia Group (HIOHG); IV Normovolemia (IVNG); and IV Hypovolemia Group (IVHG). Swine were anesthetized. The HIOH and IVH subjects were exsanguinated 35% of their blood volume. Each was placed into arrest. After 2 minutes, cardiopulmonary resuscitation was initiated. After another 2 minutes, 1 mg of epinephrine was given by IV or HIO routes; blood samples were collected over 5 minutes and analyzed by high-performance liquid chromatography. Subjects were defibrillated every 2 minutes.

RESULTS

The AUC in the HIOHG was significantly less than both the HIONG (p = 0.047) and IVHG (p = 0.021). There were no other significant differences in the groups relative to AUC (p > 0.05). HIONG had a significantly higher occurrence of ROSC compared to HIOHG (p = 0.018) and IVH (p =0.018) but no other significant differences (p > 0.05). The odds of ROSC were 19.2 times greater for HIONG compared to the HIOHG.

CONCLUSION

The study strongly supports the effectiveness of HIO administration of epinephrine and should be considered as a first-line intervention for patients in cardiac arrest related to normovolemic causes. However, our findings do not support using HIO access for epinephrine administration for patients in cardiac arrest related to hypovolemic reasons.