Effects of epinephrine and vasopressin on cerebral microcirculatory flows during and after cardiopulmonary resuscitation

Association between defibrillation-to-adrenaline interval and short-term outcomes in patients with out-of-hospital cardiac arrest and an initial shockable rhythm

Aim

The optimal timing of adrenaline administration after defibrillation in patients with out-of-hospital cardiac arrest (OHCA) and an initial shockable rhythm is unknown. We investigated the association between the defibrillation-to-adrenaline interval and clinical outcomes.

Methods

Between 2011 and 2020, we enrolled 1,259,960 patients with OHCA into a nationwide prospective population-based registry in Japan. After applying exclusion criteria, 20,905 patients with an initial shockable rhythm documented at emergency medical services (EMS) arrival who received adrenaline after defibrillation were eligible for this study. Multivariable logistic regression analysis was used to predict favourable short-term outcomes: prehospital return of spontaneous circulation (ROSC), 30-day survival, or a favourable neurological outcome (Cerebral Performance Category 1 or 2) at 30 days. Patients were categorised into 2-minute defibrillation-to-adrenaline intervals up to 18 min, or more than 18 min.

Results

At 30 days, 1,618 patients (8%) had a favourable neurological outcome. The defibrillation-to-adrenaline interval in these patients was significantly shorter than in patients with an unfavourable neurological outcome [8 (5-12) vs 11 (7-16) minutes; P < 0.001]. The proportion of patients with prehospital ROSC, 30-day survival, or a favourable neurological outcome at 30 days decreased as the defibrillation-to-adrenaline interval increased (P < 0.001 for trend). Multivariable analysis revealed that a defibrillation-to-adrenaline interval of > 6 min was an independent predictor of worse prehospital ROSC, 30-day survival, or neurological outcome at 30 days when compared with an interval of 4-6 min.

Conclusion

A longer defibrillation-to-adrenaline interval was significantly associated with worse short-term outcomes in patients with OHCA and an initial shockable rhythm.

The Pharmacologic Management of Cardiac Arrest

The effectiveness of pharmacologic management of cardiac arrest patients is widely debated; however, several studies published in the past 5 years have begun to clarify some of these issues. This article covers the current state of evidence for the effectiveness of the vasopressor epinephrine and the combination of vasopressin-steroids-epinephrine and antiarrhythmic medications amiodarone and lidocaine and reviews the role of other medications such as calcium, sodium bicarbonate, magnesium, and atropine in cardiac arrest care. We additionally review the role of β-blockers for refractory pulseless ventricular tachycardia/ventricular fibrillation and thrombolytics in undifferentiated cardiac arrest and suspected fatal pulmonary embolism.

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.

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

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

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.

Monitoring of Brain Tissue Oxygen Tension in Cardiac Arrest: a Translational Systematic Review from Experimental to Clinical Evidence

BACKGROUND

Cardiac arrest (CA) is a sudden event that is often characterized by hypoxic-ischemic brain injury (HIBI), leading to significant mortality and long-term disability. Brain tissue oxygenation (PbtO2) is an invasive tool for monitoring brain oxygen tension, but it is not routinely used in patients with CA because of the invasiveness and the absence of high-quality data on its effect on outcome. We conducted a systematic review of experimental and clinical evidence to understand the role of PbtO2 in monitoring brain oxygenation in HIBI after CA and the effect of targeted PbtO2 therapy on outcomes.

METHODS

The search was conducted using four search engines (PubMed, Scopus, Embase, and Cochrane), using the Boolean operator to combine mesh terms such as PbtO2, CA, and HIBI.

RESULTS

Among 1,077 records, 22 studies were included (16 experimental studies and six clinical studies). In experimental studies, PbtO2 was mainly adopted to assess the impact of gas exchanges, drugs, or systemic maneuvers on brain oxygenation. In human studies, PbtO2 was rarely used to monitor the brain oxygen tension in patients with CA and HIBI. PbtO2 values had no clear association with patients' outcomes, but in the experimental studies, brain tissue hypoxia was associated with increased inflammation and neuronal damage.

CONCLUSIONS

Further studies are needed to validate the effect and the threshold of PbtO2 associated with outcome in patients with CA, as well as to understand the physiological mechanisms influencing PbtO2 induced by gas exchanges, drug administration, and changes in body positioning after CA.

The Impact of Inotropes and Vasopressors on Cerebral Oxygenation in Patients with Traumatic Brain Injury and Subarachnoid Hemorrhage: A Narrative Review

Traumatic brain injury (TBI) and subarachnoid hemorrhage (SAH) are critical neurological conditions that necessitate specialized care in the Intensive Care Unit (ICU). Managing cerebral perfusion pressure (CPP) and mean arterial pressure (MAP) is of primary importance in these patients. To maintain targeted MAP and CPP, vasopressors and/or inotropes are commonly used. However, their effects on cerebral oxygenation are not fully understood. The aim of this review is to provide an up-to date review regarding the current uses and pathophysiological issues related to the use of vasopressors and inotropes in TBI and SAH patients. According to our findings, despite achieving similar hemodynamic parameters and CPP, the effects of various vasopressors and inotropes on cerebral oxygenation, local CBF and metabolism are heterogeneous. Therefore, a more accurate understanding of the cerebral activity of these medications is crucial for optimizing patient management in the ICU setting.

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.

The Pharmacologic Management of Cardiac Arrest

The effectiveness of pharmacologic management of cardiac arrest patients is widely debated; however, several studies published in the past 5 years have begun to clarify some of these issues. This article covers the current state of evidence for the effectiveness of the vasopressor epinephrine and the combination of vasopressin-steroids-epinephrine and antiarrhythmic medications amiodarone and lidocaine and reviews the role of other medications such as calcium, sodium bicarbonate, magnesium, and atropine in cardiac arrest care. We additionally review the role of β-blockers for refractory pulseless ventricular tachycardia/ventricular fibrillation and thrombolytics in undifferentiated cardiac arrest and suspected fatal pulmonary embolism.

Preclinical evaluation of triiodothyronine nanoparticles as a novel therapeutic intervention for resuscitation from cardiac arrest

BACKGROUND

Given emerging evidence of rapid non-genomic cytoprotective effects of triiodothyronine (T3), we evaluated the resuscitative efficacy of two nanoparticle formulations of T3 (T3np) designed to prolong cell membrane receptor-mediated signaling.

METHODS

Swine (n = 40) were randomized to intravenous vehicle (empty np), EPI (0.015 mg/kg), T3np (0.125 mg/kg), or T3np loaded with phosphocreatine (T3np + PCr; 0.125 mg/kg) during CPR following 7-min cardiac arrest (n = 10/group). Hemodynamics and biomarkers of heart (cardiac troponin I; cTnI) and brain (neuron-specific enolase; NSE) injury were assessed for up to 4-hours post-ROSC, at which time the heart and brain were collected for post-mortem analysis.

RESULTS

Compared with vehicle (4/10), the rate of ROSC was higher in swine receiving T3np (10/10; p < 0.01), T3np + PCr (8/10; p = 0.08) or EPI (10/10; p < 0.01) during CPR. Although time to ROSC and survival duration were comparable between groups, EPI was associated with a ∼2-fold higher post-ROSC concentration of cTnI vs T3np and T3np + PCr and the early post-ROSC rise in NSE and neuronal injury were attenuated in T3np-treated vs EPI-treated animals. Analysis of hippocampal ultrastructure revealed deterioration of mitochondrial integrity, reduced active zone length, and increased axonal vacuolization in EPI-treated animals vs controls. However, the frequency of these abnormalities was diminished in animals resuscitated with T3np.

CONCLUSIONS

T3np achieved a ROSC rate and post-ROSC survival that was superior to vehicle and comparable to EPI. The attenuation of selected biomarkers of cardiac and neurologic injury at individual early post-ROSC timepoints in T3np-treated vs EPI-treated animals suggests that T3np administration during CPR may lead to more favorable outcomes in cardiac arrest.

The physiologic response to epinephrine and pediatric cardiopulmonary resuscitation outcomes

BACKGROUND

Epinephrine is provided during cardiopulmonary resuscitation (CPR) to increase systemic vascular resistance and generate higher diastolic blood pressure (DBP) to improve coronary perfusion and attain return of spontaneous circulation (ROSC). The DBP response to epinephrine during pediatric CPR and its association with outcomes have not been well described. Thus, the objective of this study was to measure the association between change in DBP after epinephrine administration during CPR and ROSC.

METHODS

This was a prospective multicenter study of children receiving ≥ 1 min of CPR with ≥ 1 dose of epinephrine and evaluable invasive arterial BP data in the 18 ICUs of the ICU-RESUS trial (NCT02837497). Blood pressure waveforms underwent compression-by-compression quantitative analysis. The mean DBP before first epinephrine dose was compared to mean DBP two minutes post-epinephrine. Patients with ≥ 5 mmHg increase in DBP were characterized as "responders."

RESULTS

Among 147 patients meeting inclusion criteria, 66 (45%) were characterized as responders and 81 (55%) were non-responders. The mean increase in DBP with epinephrine was 4.4 [- 1.9, 11.5] mmHg (responders: 13.6 [7.5, 29.3] mmHg versus non-responders: - 1.5 [- 5.0, 1.5] mmHg; p < 0.001). After controlling for a priori selected covariates, epinephrine response was associated with ROSC (aRR 1.60 [1.21, 2.12]; p = 0.001). Sensitivity analyses identified similar associations between DBP response thresholds of ≥ 10, 15, and 20 mmHg and ROSC; DBP responses of ≥ 10 and ≥ 15 mmHg were associated with higher aRR of survival to hospital discharge and survival with favorable neurologic outcome (Pediatric Cerebral Performance Category score of 1-3 or no worsening from baseline).

CONCLUSIONS

The change in DBP following epinephrine administration during pediatric in-hospital CPR was associated with return of spontaneous circulation.

Bolus Vasopressor Use for Air Medical Rapid Sequence Intubation: The Vasopressor Intravenous Push to Enhance Resuscitation Trial

BACKGROUND

Rapid sequence intubation (RSI) may compromise perfusion because of the use of sympatholytic medications as well as subsequent positive pressure ventilation. The use of bolus vasopressor agents may reverse hypotension and prevent arrest.

METHODS

This was a prospective, observational study enrolling air medical patients with critical peri-RSI hypotension (systolic blood pressure [SBP] < 90 mm Hg) to receive either arginine vasopressin (aVP), 2 U intravenously every 5 minutes, for trauma patients or phenylephrine (PE), 200 μg intravenously every 5 minutes, for nontrauma patients. The main outcome measures included an increase in SBP, a reversal of hypotension, and the occurrence of dysrhythmia or hypertension (SBP > 160 mm Hg) within 20 minutes of vasopressor administration.

RESULTS

A total of 523 patients (344 aVP and 179 PE) were enrolled over 2 years. An increase in SBP was observed in 326 aVP patients (95%), with reversal of hypotension in 272 patients (79%). An increase in SBP was observed in 171 PE patients (96%), with reversal of hypotension in 148 patients (83%). A low rate of rebound hypertension was observed for both aVP and PE patients.

CONCLUSION

Both aVP and PE appear to be safe and effective for treating critical hypotension in the peri-RSI period.

Extracorporeal cardiopulmonary resuscitation (eCPR) and cerebral perfusion: A narrative review

Extracorporeal cardiopulmonary resuscitation (eCPR) is emerging as an effective, lifesaving resuscitation strategy for select patients with prolonged or refractory cardiac arrest. Currently, a paucity of evidence-based recommendations is available to guide clinical management of eCPR patients. Despite promising results from initial clinical trials, neurological injury remains a significant cause of morbidity and mortality. Neuropathology associated with utilization of an extracorporeal circuit may interact significantly with the consequences of a prolonged low-flow state that typically precedes eCPR. In this narrative review, we explore current gaps in knowledge about cerebral perfusion over the course of cardiac arrest and resuscitation with a focus on patients treated with eCPR. We found no studies which investigated regional cerebral blood flow or cerebral autoregulation in human cohorts specific to eCPR. Studies which assessed cerebral perfusion in clinical eCPR were small and limited to near-infrared spectroscopy. Furthermore, no studies prospectively or retrospectively evaluated the relationship between epinephrine and neurological outcomes in eCPR patients. In summary, the field currently lacks a comprehensive understanding of how regional cerebral perfusion and cerebral autoregulation are temporally modified by factors such as pre-eCPR low-flow duration, vasopressors, and circuit flow rate. Elucidating these critical relationships may inform future strategies aimed at improving neurological outcomes in patients treated with lifesaving eCPR.

Effects of adrenaline and vasopressin on cerebral microcirculation at baseline and during global brain ischemia and reperfusion in rabbits

BACKGROUND

During cardiopulmonary resuscitation, the brain becomes ischemic. Adrenaline and vasopressin have been recommended for use during cardiopulmonary resuscitation. We aimed to investigate the direct effects of adrenaline and vasopressin on the cerebral microvasculature at baseline and during ischemia and reperfusion in rabbits.

METHODS

The closed cranial window method was used to visualize the cerebral microcirculation and changes in the pial arteriole diameter in rabbits. Adrenaline and vasopressin were administered topically on the brain tissue. First, the effects of adrenaline and vasopressin on pial arterioles were evaluated in 7 rabbits that were given 4 different concentrations of adrenaline, and another 7 rabbits that received 4 different concentrations of vasopressin. Second, the effects of adrenaline and vasopressin were determined during the global brain ischemia and reperfusion, which was induced by clamping the brachiocephalic, left common carotid, and left subclavian arteries for 15 min. An additional 21 rabbits were randomly assigned to receive artificial cerebrospinal fluid (aCSF) (n = 7), adrenaline 10^-5 mol/L (n = 7), or vasopressin 10^-7 mol/L (n = 7). Each drug was continuously infused from 5 min after the initiation of ischemia until 120 min after reperfusion. The pial arteriole diameters were recorded before and during ischemia, and after reperfusion.

RESULTS

At baseline, adrenaline and vasopressin did not affect the cerebral pial arterioles. During ischemia, vasopressin, but not aCSF and adrenaline constricted the pial vessels. Late in the reperfusion phase, pial diameter became reduced in the vasopressin and aCSF groups whereas pial diameter was higher in the animals treated with adrenaline.

CONCLUSIONS

Adrenaline and vasopressin did not affect pial arterioles at baseline. During reperfusion, adrenaline may counteract the cerebral vasoconstriction.

Resuscitation with epinephrine worsens cerebral capillary no-reflow after experimental pediatric cardiac arrest: An in vivo multiphoton microscopy evaluation

Epinephrine is the principal resuscitation therapy for pediatric cardiac arrest (CA). Clinical data suggest that although epinephrine increases the rate of resuscitation, it fails to improve neurological outcome, possibly secondary to reductions in microvascular flow. We characterized the effect of epinephrine vs. placebo administered at resuscitation from pediatric asphyxial CA on microvascular and macrovascular cortical perfusion assessed using in vivo multiphoton microscopy and laser speckle flowmetry, respectively, and on brain tissue oxygenation (PbO₂), behavioral outcomes, and neuropathology in 16-18-day-old rats. Epinephrine-treated rats had a more rapid return of spontaneous circulation and brisk immediate cortical reperfusion during 1-3 min post-CA vs. placebo. However, at the microvascular level, epinephrine-treated rats had penetrating arteriole constriction and increases in both capillary stalling (no-reflow) and cortical capillary transit time 30-60 min post-CA vs. placebo. Placebo-treated rats had increased capillary diameters post-CA. The cortex was hypoxic post-CA in both groups. Epinephrine treatment worsened reference memory performance vs. shams. Hippocampal neuron counts did not differ between groups. Resuscitation with epinephrine enhanced immediate reperfusion but produced microvascular alterations during the first hour post-resuscitation, characterized by vasoconstriction, capillary stasis, prolonged cortical transit time, and absence of compensatory cortical vasodilation. Targeted therapies mitigating the deleterious microvascular effects of epinephrine are needed.

Predictors of neurological outcome after out-of-hospital cardiac arrest: sex-based analysis: do males derive greater benefit from hypothermia management than females?

Background

Previous studies of the effect of sex on after out-of-hospital cardiac arrest (OHCA) outcomes focused on survival to hospital discharge and 1-month survival. Studies on the effect of sex on neurological function after OHCA are still limited. The objective of this study was to identify the predictors of favorable neurological outcome and to examine the association between sex as a biological variable and favorable neurological outcome OHCA.

Methods

Retrospective analyses of clustered data from the Resuscitation Outcomes Consortium multi-center randomized controlled trial (2011–2015). We included adults with non-traumatic OHCA and EMS-attended OHCA. We used multilevel logistic regression to examine the association between sex and favorable neurological outcomes (modified Rankin Scale) and to identify the predictors of favorable neurological outcome.

Results

In total, 22,416 patients were included. Of those, 8109 (36.2%) were females. The multilevel analysis identified the following variables as significant predictors of favorable neurological outcome: younger age, shorter duration of EMS arrival to the scene, arrest in public location, witnessed arrest, bystander CPR, chest compression rate (CCR) of 100–120 compressions per minute, induction of hypothermia, and initial shockable rhythm. Two variables, insertion of an advanced airway and administration of epinephrine, were associated with poor neurological outcome. Our analysis showed that males have higher crude rates of survival with favorable neurological outcome (8.6 vs. 4.9%, p < 0.001). However, the adjusted rate was not significant. Further analyses showed that hypothermia had a significantly greater effect on males than females.

Conclusions

Males had significantly higher crude rates of survival with favorable neurological outcome. However, the adjusted rate was not statistically significant. Males derived significantly greater benefit from hypothermia management than females, but this can possibly be explained by differences in arrest characteristics or in-hospital treatment. In-depth confirmatory studies on the hypothermia effect size by sex are required.

A randomised preclinical trial of adrenaline use during cardiac arrest in mice

Background

Adrenaline is routinely administered during cardiac arrest resuscitation. Using a novel murine model of cardiac arrest, this study evaluates the effects of adrenaline use on survival and end-organ injury.

Methods

A total of 58 mice, including cardiac arrest (CA) and sham (SHAM) groups received intravenous potassium chloride either as a bolus (CA) or slow infusion (SHAM), inducing ECG-confirmed asystole (in CA only) for 4-minutes prior to intravenous adrenaline (+ADR;250 ul,32 ug/ml) or saline (-ADR;250 ul) and manual chest compressions (300 BPM) for 4-minutes. Mice with return of spontaneous circulation (ROSC) were assessed at 24- or 72-h timepoints.

Results

Among animals that underwent CA, rates of ROSC (n = 21 (95 %) vs n = 14 (82 %), P = 0.18) and survival to the planned endpoint (n = 11 (50 %) vs n = 12 (71 %), P = 0.19) were similar when comparing those treated with (CA+ADR) and without (CA-ADR) adrenaline. However, in CA animals that initially achieved ROSC, subsequent mortality was approximately 3-fold greater with adrenaline treatment (48 % vs 14 %, P = 0.042). Among SHAM animals, adrenaline use had no impact on survival rates or other endpoints. Greater myocardial injury occurred in CA+ADR vs CA-ADR, with increased Hs-Troponin levels measured at 24- (26.0 ± 0.9 vs 9.4 ± 5.3 ng/mL, P = 0.015) and 72-h (20.9 ± 8.3 vs 5.0 ± 2.4 ng/mL, P = 0.012), associated with increased expression of pro-inflammatory and fibrotic genes within cardiac and renal tissue.

Conclusion

Adrenaline did not improve ROSC or overall survival but following successful ROSC, its use resulted in 3-fold greater mortality rates. Adrenaline was also associated with increased myocardial injury, end-organ inflammation, and fibrosis. These findings underscore the need for further preclinical evaluation of alternate pharmacologic adjuncts for cardiopulmonary resuscitation that improve survival and limit end-organ injury.

Automated aortic endovascular balloon volume titration prevents re-arrest immediately after return of spontaneous circulation in a swine model of nontraumatic cardiac arrest

Objectives

Endovascular aortic occlusion as an adjunct to cardiopulmonary resuscitation (CPR) for non-traumatic cardiac arrest is gaining interest. In a recent clinical trial, return of spontaneous circulation (ROSC) was achieved despite prolonged no-flow times. However, 66% of patients re-arrested upon balloon deflation. We aimed to determine if automated titration of endovascular balloon volume following ROSC can augment diastolic blood pressure (DBP) to prevent re-arrest.

Methods

Twenty swine were anesthetized and placed into ventricular fibrillation (VF). Following 7 minutes of no-flow VF and 5 minutes of mechanical CPR, animals were subjected to complete aortic occlusion to adjunct CPR. Upon ROSC, the balloon was either deflated steadily over 5 minutes (control) or underwent automated, dynamic adjustments to maintain a DBP of 60 mmHg (Endovascular Variable Aortic Control, EVAC).

Results

ROSC was obtained in ten animals (5 EVAC, 5 REBOA). Sixty percent (3/5) of control animals rearrested while none of the EVAC animals rearrested (p = 0.038). Animals in the EVAC group spent a significantly higher proportion of the post-ROSC period with a DBP > 60 mmHg [median (IQR)] [control 79.7 (72.5–86.0)%; EVAC 97.7 (90.8–99.7)%, p = 0.047]. The EVAC group had a statistically significant reduction in arterial lactate concentration [7.98 (7.4–8.16) mmol/L] compared to control [9.93 (8.86–10.45) mmol/L, p = 0.047]. There were no statistical differences between the two groups in the amount of adrenaline (epinephrine) required.

Conclusion

In our swine model of cardiac arrest, automated aortic endovascular balloon titration improved DBP and prevented re-arrest in the first 20 minutes after ROSC.

Effects of Sodium Nitroprusside Administered Via a Subdural Intracranial Catheter on the Microcirculation, Oxygenation, and Electrocortical Activity of the Cerebral Cortex in a Pig Cardiac Arrest Model

Background

Postischemic cerebral hypoperfusion has been indicated as an important contributing factor to secondary cerebral injury after cardiac arrest. We evaluated the effects of sodium nitroprusside administered via a subdural intracranial catheter on the microcirculation, oxygenation, and electrocortical activity of the cerebral cortex in the early postresuscitation period using a pig model of cardiac arrest.

Methods and Results

Twenty‐nine pigs were resuscitated with closed cardiopulmonary resuscitation after 14 minutes of untreated ventricular fibrillation. Thirty minutes after restoration of spontaneous circulation, 24 pigs randomly received either 4 mg of sodium nitroprusside (IT‐SNP group) or saline placebo (IT‐saline group) via subdural intracranial catheters and were observed for 5 hours. The same dose of sodium nitroprusside was administered intravenously in another 5 pigs. Compared with the IT‐saline group, the IT‐SNP group had larger areas under the curve for tissue oxygen tension and percent changes of arteriole diameter and number of perfused microvessels from baseline (all P<0.05) monitored on the cerebral cortex during the 5‐hour period, without severe hemodynamic instability. This group also showed faster recovery of electrocortical activity measured using amplitude‐integrated electroencephalography. Repeated‐measures analysis of variance revealed significant group–time interactions for these parameters. Intravenously administered sodium nitroprusside caused profound hypotension but did not appear to increase the cerebral parameters.

Conclusions

Sodium nitroprusside administered via a subdural intracranial catheter increased post–restoration of spontaneous circulation cerebral cortical microcirculation and oxygenation and hastened electrocortical activity recovery in a pig model of cardiac arrest. Further studies are required to determine its impact on the long‐term neurologic outcomes.

Effect of adrenaline dose on neurological outcome in out-of-hospital cardiac arrest: a nationwide propensity score analysis

BACKGROUND

Adrenaline is recommended during cardio-pulmonary resuscitation. The optimal dose remains debated, and the effect of lower than recommended dose is unknown.

OBJECTIVE

To compare the outcome of patients treated with the recommended, lower or higher cumulative doses of adrenaline.

DESIGN, SETTINGS, PARTICIPANTS

Patients were included from the French National Cardiac Arrest Registry and were grouped based on the received dose of adrenaline: recommended, higher and lower dose.

OUTCOME MEASURES AND ANALYSIS

The primary endpoint was good neurologic outcome at 30 days post-OHCA, defined by a cerebral performance category (CPC) of less than 3. Secondary endpoints included return of spontaneous circulation and survival to hospital discharge. A multiple propensity score adjustment approach was performed.

MAIN RESULTS

27 309 patients included from July 1st 2011 to January 1st 2019 were analysed, mean age was 68 (57-78) years and 11.2% had ventricular fibrillation. 588 (2.2%) patients survived with a good CPC score. After adjustment, patients in the high dose group had a significant lower rate of good neurologic outcome (OR, 0.6; 95% CI, 0.5-0.7). There was no significant difference for the primary endpoint in the lower dose group (OR, 0.8; 95% CI, 0.7-1.1). There was a lower rate of survival to hospital discharge in the high-dose group vs. standard group (OR, 0.5; 95% CI, 0.5-0.6).

CONCLUSION

The use of lower doses of adrenaline was not associated with a significant difference on survival good neurologic outcomes at D30. But a higher dose of adrenaline was associated with a lower rate of survival with good neurological outcomes and poorer survival at D30.

Effect of Prehospital Epinephrine on Out-of-Hospital Cardiac Arrest Outcomes: A Propensity Score-Matched Analysis

PURPOSE

A pilot project using epinephrine at the scene under medical control is currently underway in Korea. This study aimed to determine whether prehospital epinephrine administration is associated with improved survival and neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients who received epinephrine during cardiopulmonary resuscitation (CPR) in the emergency department.

MATERIALS AND METHODS

This retrospective observational study used a nationwide multicenter OHCA registry. Patients were classified into two groups according to whether they received epinephrine at the scene or not. The associations between prehospital epinephrine use and outcomes were assessed using propensity score (PS)-matched analysis. Multivariable logistic regression analysis was performed using PS matching. The same analysis was repeated for the subgroup of patients with non-shockable rhythm.

RESULTS

PS matching was performed for 1084 patients in each group. Survival to discharge was significantly decreased in the patients who received prehospital epinephrine [odds ratio (OR) 0.415, 95% confidence interval (CI) 0.250-0.670, p<0.001]. However, no statistical significance was observed for good neurological outcome (OR 0.548, 95% CI 0.258-1.123, p=0.105). For the patient subgroup with non-shockable rhythm, prehospital epinephrine was also associated with lower survival to discharge (OR 0.514, 95% CI 0.306-0.844, p=0.010), but not with neurological outcome (OR 0.709, 95% CI 0.323-1.529, p=0.382).

CONCLUSION

Prehospital epinephrine administration was associated with decreased survival rates in OHCA patients but not statistically associated with neurological outcome in this PS-matched analysis. Further research is required to investigate the reason for the detrimental effect of epinephrine administered at the scene.

A comprehensive neuromonitoring approach in a large animal model of cardiac arrest

Background

Anoxic brain injuries represent the main determinant of poor outcome after cardiac arrest (CA). Large animal models have been described to investigate new treatments during CA and post‐resuscitation phase, but a detailed model that includes extensive neuromonitoring is lacking.

Method

Before an electrically‐induced 10‐minute CA and resuscitation, 46 adult pigs underwent neurosurgery for placement of a multifunctional probe (intracranial pressure or ICP, tissue oxygen tension or PbtO₂ and cerebral temperature) and a bolt‐based technique for the placement and securing of a regional blood flow probe and two sEEG electrodes; two modified cerebral microdialysis (CMD) probes were also inserted in the frontal lobes and accidental misplacement was prevented using a perforated head support.

Result

42 animals underwent the CA procedure and 41 achieved the return of spontaneous circulation (ROSC). In 4 cases (8.6%) an adverse event took place during preparation, but only in two cases (4.3%) this was related to the neurosurgery. In 6 animals (13.3%) the minor complications that occurred resolved after probe repositioning.

Conclusion

Herein we provide a detailed comprehensive neuromonitoring approach in a large animal model of CA that might help future research.

Epinephrine before defibrillation in patients with shockable in-hospital cardiac arrest: propensity matched analysis

OBJECTIVE

To determine the use of epinephrine (adrenaline) before defibrillation for treatment of in-hospital cardiac arrest due to a ventricular arrhythmia and examine its association with patient survival.

DESIGN

Propensity matched analysis.

SETTING

2000-18 data from 497 hospitals participating in the American Heart Association’s Get With The Guidelines-Resuscitation registry.

PARTICIPANTS

Adults aged 18 and older with an index in-hospital cardiac arrest due to an initial shockable rhythm treated with defibrillation.

INTERVENTIONS

Administration of epinephrine before first defibrillation.

MAIN OUTCOME MEASURES

Survival to discharge; favorable neurological survival, defined as survival to discharge with none, mild, or moderate neurological disability measured using cerebral performance category scores; and survival after acute resuscitation (that is, return of spontaneous circulation for &gt;20 minutes). A time dependent, propensity matched analysis was performed to adjust for confounding due to indication and evaluate the independent association of epinephrine before defibrillation with study outcomes.

RESULTS

Among 34 820 patients with an initial shockable rhythm, 7054 (20.3%) were treated with epinephrine before defibrillation, contrary to current guidelines. In comparison with participants treated with defibrillation first, participants receiving epinephrine first were less likely to have a history of myocardial infarction or heart failure, but more likely to have renal failure, sepsis, respiratory insufficiency, and receive mechanical ventilation before in-hospital cardiac arrest (standardized differences &gt;10% for all). Treatment with epinephrine before defibrillation was strongly associated with delayed defibrillation (median 4 minutes v 0 minutes). In propensity matched analysis (6569 matched pairs), epinephrine before defibrillation was associated with lower odds of survival to discharge (22.4% v 29.7%; adjusted odds ratio 0.69; 95% confidence interval 0.64 to 0.74; P&lt;0.001), favorable neurological survival (15.8% v 21.6%; 0.68; 0.61 to 0.76; P&lt;0.001) and survival after acute resuscitation (61.7% v 69.5%; 0.73; 0.67 to 0.79; P&lt;0.001). The above findings were consistent in a range of sensitivity analyses, including matching according to defibrillation time.

CONCLUSIONS

Contrary to current guidelines that prioritize immediate defibrillation for in-hospital cardiac arrest due to a shockable rhythm, one in five patients are treated with epinephrine before defibrillation. Use of epinephrine before defibrillation was associated with worse survival outcomes.

Mildly Reduced Doses of Adrenaline Do Not Affect Key Hemodynamic Parameters during Cardio-Pulmonary Resuscitation in a Pig Model of Cardiac Arrest

Adrenaline is recommended for cardiac arrest resuscitation, but its effectiveness has been questioned recently. Achieving return of spontaneous circulation (ROSC) is essential and is obtained by increasing coronary perfusion pressure (CPP) after adrenaline injection. A threshold as high as 35 mmHg of CPP may be necessary to obtain ROSC, but increasing doses of adrenaline might be harmful to the brain. Our study aimed to compare the increase in CPP with reduced doses of adrenaline to the recommended 1 mg dose in a pig model of cardiac arrest. Fifteen domestic pigs were randomized into three groups according to the adrenaline doses: 1 mg, 0.5 mg, or 0.25 mg administered every 5 min. Cardiac arrest was induced by ventricular fibrillation; after 5 min of no-flow, mechanical chest compression was resumed. The Wilcoxon test and Kruskal-Wallis exact test were used for the comparison of groups. Fisher's exact test was used to compare categorical variables. CPP, EtCO2 level, cerebral, and tissue near-infrared spectroscopy (NIRS) were measured. CPP was significantly lower in the 0.25 mg group 90 s after the first adrenaline injection: 28.9 (21.2; 35.4) vs. 53.8 (37.8; 58.2) in the 1 mg group (p = 0.008), while there was no significant difference with 0.5 mg 39.6 (32.7; 52.5) (p = 0.056). Overall, 0.25 mg did not achieve the threshold of 35 mmHg. EtCO2 levels were higher at T12 and T14 in the 0.5 mg than in the standard group: 32 (23; 35) vs. 19 (16; 26) and 26 (20; 34) vs. 19 (12; 22) (p < 0.05). Cerebral and tissue NIRS did not show a significant difference between the three groups. CPP after 0.5 mg boluses of adrenaline was not significantly different from the recommended 1 mg in our model of cardiac arrest.

Adrenaline improves regional cerebral blood flow, cerebral oxygenation and cerebral metabolism during CPR in a porcine cardiac arrest model using low-flow extracorporeal support

BACKGROUND

The effects of adrenaline on cerebral blood vessels during cardiopulmonary resuscitation (CPR) are not well understood. We developed an extracorporeal CPR model that maintains constant low systemic blood flow while allowing adrenaline-associated effects on cerebral vasculature to be assessed at different mean arterial pressure (MAP) levels independently of the effects on systemic blood flow.

METHODS

After eight minutes of cardiac arrest, low-flow extracorporeal life support (ECLS) (30 ml/kg/min) was started in fourteen pigs. After ten minutes, continuous adrenaline administration was started to achieve MAP values of 40 (n = 7) or 60 mmHg (n = 7). Measurements included intracranial pressure (ICP), cerebral perfusion pressure (CePP), laser-Doppler-derived regional cerebral blood flow (CBF), cerebral regional oxygen saturation (rSO₂), brain tissue oxygen tension (P_btO₂) and extracellular cerebral metabolites assessed by cerebral microdialysis.

RESULTS

During ECLS without adrenaline, regional CBF increased by only 5% (25th to 75th percentile: -3 to 14; p=0.2642) and P_btO₂ by 6% (0-15; p=0.0073) despite a significant increase in MAP to 28 mmHg (25-30; p<0.0001) and CePP to 10 mmHg (8-13; p<0.0001). Accordingly, cerebral microdialysis parameters showed a profound hypoxic-ischemic pattern. Adrenaline administration significantly improved regional CBF to 29±14% (p=0.0098) and 61±25% (p<0.001) and P_btO₂ to 15±11% and 130±82% (both p<0.001) of baseline in the MAP 40 mmHg and MAP 60 mmHg groups, respectively. Importantly, MAP of 60 mmHg was associated with metabolic improvement.

CONCLUSION

This study shows that adrenaline administration during constant low systemic blood flow increases CePP, regional CBF, cerebral oxygenation and cerebral metabolism.

Relationship between the Plasma Levels of Catecholamines and Return of Spontaneous Circulation in Patients with Out-of-Hospital Cardiac Arrest

Purpose

The dynamic state of epinephrine (Ep) in the plasma of patients with out-of-hospital cardiac arrest (OHCA) remains unclear. The purpose of this study was to evaluate the relationship between the plasma levels of catecholamines (such as epinephrine (Ep), norepinephrine (Nep), and dopamine) and vasopressin (antidiuretic hormone (ADH)) and the acquisition of return of spontaneous circulation (ROSC) in OHCA patients.

Methods

This was a prospective, observational clinical study. Patients with OHCA transferred to our hospital between July 2014 and July 2017 were enrolled. The levels of catecholamines and ADH in the plasma were measured using blood samples immediately obtained on arrival at our hospital and before the administration of Ep. Patients in whom Ep was already administered prior to obtaining blood samples were excluded. Patients were divided into two groups: with and without ROSC, that is, ROSC (+) and ROSC (−) groups, respectively. The plasma levels of these agents and the conditions of resuscitation were compared between the two groups.

Results

A total of 96 patients with OHCA were analyzed. The ROSC (+) and ROSC (−) groups included 34 and 62 patients, respectively. There were no significant differences observed between the two groups in age, cause of cardiopulmonary arrest, and prehospital resuscitation time. The plasma levels of Ep and Nep were significantly lower in the ROSC (+) group than in the ROSC (−) group. However, there were no significant differences in the plasma levels of dopamine and ADH between the two groups.

Conclusion

Increased levels of Ep in the plasma may not be associated with the acquisition of ROSC in patients with OHCA.

The Effect of Epinephrine Dosing Intervals on Outcomes from Pediatric In-Hospital Cardiac Arrest

RATIONALE

Animal studies of cardiac arrest suggest shorter epinephrine dosing intervals than currently recommended (every 3-5 minutes) may be beneficial in select circumstances.

OBJECTIVES

To evaluate the association between epinephrine dosing intervals and pediatric cardiac arrest outcomes.

METHODS

Single-center retrospective cohort study of children (<18 years of age) who received ≥1 minute of cardiopulmonary resuscitation and ≥2 doses of epinephrine for an index in-hospital cardiac arrest. Exposure was epinephrine dosing interval: ≤2 minutes (frequent epinephrine) vs. >2 minutes. Primary outcome was survival to hospital discharge with a favorable neurobehavioral outcome (Pediatric Cerebral Performance Category score 1-2 or unchanged). Logistic regression evaluated the association between dosing interval and outcomes; additional analyses explored duration of CPR as a mediator. In a subgroup, the effect of dosing interval on diastolic blood pressure was investigated.

MEASUREMENTS AND MAIN RESULTS

Between January 2011 and December 2018, 125 patients met inclusion/exclusion criteria; 33 (26%) received frequent epinephrine. Frequent epinephrine was associated with increased odds of survival with favorable neurobehavioral outcome (aOR 2.56; CI95 1.07, 6.14; p=0.036), with 66% of the association mediated by CPR duration. Delta diastolic blood pressure was greater after the second dose of epinephrine among patients who received frequent epinephrine (median [IQR] 6.3 [4.1, 16.9] vs. 0.13 [-2.3, 1.9] mmHg, p=0.034).

CONCLUSIONS

In patients who received at least two doses of epinephrine, dosing intervals ≤2 minutes were associated with improved neurobehavioral outcomes compared to dosing intervals >2 minutes. Mediation analysis suggests improved outcomes are largely due to frequent epinephrine shortening duration of CPR.

Cardiopulmonary Resuscitation and Rescue Therapies

The history of cardiopulmonary resuscitation and the Society of Critical Care Medicine have much in common, as many of the founders of the Society of Critical Care Medicine focused on understanding and improving outcomes from cardiac arrest. We review the history, the current, and future state of cardiopulmonary resuscitation.

Premenopausal-aged females have no neurological outcome advantage after out-of-hospital cardiac arrest: A multilevel analysis of North American populations

AIM

We investigated the impact of premenopausal age on neurological function at hospital discharge in patients with out-of-hospital cardiac arrest (OHCA). We hypothesized that premenopausal-aged females (18-47 years of age) with OHCA would have a higher probability of survival with favourable neurological function at hospital discharge compared with males of the same age group, older males, and older females (>53 years of age).

METHODS

Retrospective analyses of data from the Resuscitation Outcomes Consortium multi-center randomized controlled trial (June 2011-May 2015). We included adults with non-traumatic OHCA treated by emergency medical service. We stratified the cohort into four groups by age and sex: premenopausal-aged females (18-47 years of age), older females (≥53 years old), younger males (18-47 years of age), and older male. We used multilevel logistic regression to examine the association between age-sex and favourable neurological outcomes (modified Rankin Scale ≤ 3).

RESULTS

In total, 23,725 patients were included: 1050 (4.5%) premenopausal females; 1930 (8.1%) younger males; 7569 (31.9%) older females; and 13,176 (55.5%) older males. The multilevel analysis showed no difference in neurological outcome between younger males and younger females (OR 0.95, 95% CI 0.69-1.32, p = 0.75). Both older females (OR 0.36, 95% CI 0. 0.26-0.48, p < 0.001) and older males (OR 0.52, 95% CI 0.39-0.69, p < 0.001) had a significantly lower odds of favourable neurological outcome than younger females. Among all groups, older females had the worst outcomes.

CONCLUSIONS

We did not detect an association between premenopausal age and survival with good neurological outcome, suggesting females sex hormones do not impact OHCA outcomes. Our findings are not in line with results from other studies. Studies that rigorously evaluate menopausal status are required to definitively assess the impact of female sex hormones on outcomes.

Double external defibrillation for shock-refractory ventricular fibrillation cardiac arrest: A step towards standardization

Double (or dual) external defibrillation (DED) has increasingly been used in the last few years by a number of emergency medical services (EMS) as a last resort to terminate ventricular fibrillation and pulseless ventricular tachycardia in adult patients who remain refractory to standard defibrillation. However, no randomized controlled trials comparing DED with standard defibrillation focusing on patient-oriented outcomes as the primary objective have been published to date. Selection criteria, procedure techniques, and protocol are not clearly defined and vary across observational studies. The terms and/or nomenclature used to describe DED are confusing and vary throughout the literature. Despite increased use of DED, many questions remain as to which patients will derive the most benefit from DED, when to implement DED, and the optimal form of delivering DED. The present paper provides a brief overview of the background, procedure techniques, pad placement, and factors affecting how DED is delivered. A further objective of this paper is to offer a proposal for a uniform nomenclature and a standardized protocol in the form of a flowchart for EMS agencies to guide further clinical trials and best practices. This paper should not only help give background on novel definitions and clarify nomenclature for this practice, but more importantly should help institutions lay the groundwork for performing EMS-based large trials to further investigate the effectiveness of DED.

The physiologic response to rescue therapy with vasopressin versus epinephrine during experimental pediatric cardiac arrest

Aim

Compare vasopressin to a second dose of epinephrine as rescue therapy after ineffective initial doses of epinephrine in diverse models of pediatric in-hospital cardiac arrest.

Methods

67 one- to three-month old female swine (10−30 kg) in six experimental cohorts from one laboratory received hemodynamic-directed CPR, a resuscitation method where high quality chest compressions are provided and vasopressor administration is titrated to coronary perfusion pressure (CoPP) ≥20 mmHg. Vasopressors are given when CoPP is <20 mmHg, in sequences of two doses of 0.02 mg/kg epinephrine separated by minimum one-minute, then a rescue dose of 0.4 U/kg vasopressin followed by minimum two-minutes. Invasive measurements were used to evaluate and compare the hemodynamic and neurologic effects of each vasopressor dose.

Results

Increases in CoPP and cerebral blood flow (CBF) were greater with vasopressin rescue than epinephrine rescue (CoPP: +8.16 [4.35, 12.06] mmHg vs. + 5.43 [1.56, 9.82] mmHg, p = 0.02; CBF: +14.58 [-0.05, 38.12] vs. + 0.00 [-0.77, 18.24] perfusion units (PFU), p = 0.005). Twenty animals (30%) failed to achieve CoPP ≥20 mmHg after two doses of epinephrine; 9/20 (45%) non-responders achieved CoPP ≥20 mmHg after vasopressin. Among all animals, the increase in CBF was greater with vasopressin (+14.58 [-0.58, 38.12] vs. 0.00 [-0.77, 18.24] PFU, p = 0.005).

Conclusions

CoPP and CBF rose significantly more after rescue vasopressin than after rescue epinephrine. Importantly, CBF increased after vasopressin rescue, but not after epinephrine rescue. In the 30% that failed to meet CoPP of 20 mmHg after two doses of epinephrine, 45% achieved target CoPP with a single rescue vasopressin dose.

Epinephrine's effects on cerebrovascular and systemic hemodynamics during cardiopulmonary resuscitation

BACKGROUND

Despite controversies, epinephrine remains a mainstay of cardiopulmonary resuscitation (CPR). Recent animal studies have suggested that epinephrine may decrease cerebral blood flow (CBF) and cerebral oxygenation, possibly potentiating neurological injury during CPR. We investigated the cerebrovascular effects of intravenous epinephrine in a swine model of pediatric in-hospital cardiac arrest. The primary objectives of this study were to determine if (1) epinephrine doses have a significant acute effect on CBF and cerebral tissue oxygenation during CPR and (2) if the effect of each subsequent dose of epinephrine differs significantly from that of the first.

METHODS

One-month-old piglets (n = 20) underwent asphyxia for 7 min, ventricular fibrillation, and CPR for 10-20 min. Epinephrine (20 mcg/kg) was administered at 2, 6, 10, 14, and 18 min of CPR. Invasive (laser Doppler, brain tissue oxygen tension [PbtO₂]) and noninvasive (diffuse correlation spectroscopy and diffuse optical spectroscopy) measurements of CBF and cerebral tissue oxygenation were simultaneously recorded. Effects of subsequent epinephrine doses were compared to the first.

RESULTS

With the first epinephrine dose during CPR, CBF and cerebral tissue oxygenation increased by > 10%, as measured by each of the invasive and noninvasive measures (p < 0.001). The effects of epinephrine on CBF and cerebral tissue oxygenation decreased with subsequent doses. By the fifth dose of epinephrine, there were no demonstrable increases in CBF of cerebral tissue oxygenation. Invasive and noninvasive CBF measurements were highly correlated during asphyxia (slope effect 1.3, p < 0.001) and CPR (slope effect 0.20, p < 0.001).

CONCLUSIONS

This model suggests that epinephrine increases CBF and cerebral tissue oxygenation, but that effects wane following the third dose. Noninvasive measurements of neurological health parameters hold promise for developing and directing resuscitation strategies.

Updates in Cardiac Arrest Resuscitation

There are approximately 350,000 out-of-hospital cardiac arrests and 200,000 in-hospital cardiac arrests annually in the United States, with survival rates of approximately 5% to 10% and 24%, respectively. The critical factors that have an impact on cardiac arrest survival include prompt recognition and activation of prehospital care, early cardiopulmonary resuscitation, and rapid defibrillation. Advanced life support protocols are continually refined to optimize intracardiac arrest management and improve survival with favorable neurologic outcome. This article focuses on current treatment recommendations for adult nontraumatic cardiac arrest, with emphasis on the latest evidence and controversies regarding intracardiac arrest management.

A Time-Dependent Propensity Score Matching Approach to Assess Epinephrine Use on Patients Survival Within Out-of-Hospital Cardiac Arrest Care

BACKGROUND

Epinephrine effectiveness and safety are still questioned. It is well known that the effect of epinephrine varies depending on patients' rhythm and time to injection.

OBJECTIVE

We aimed to assess the association between epinephrine use during out-of-hospital cardiac arrest (OHCA) care and patient 30-day (D30) survival.

METHODS

Between 2011 and 2017, 27,008 OHCA patients were included from the French OHCA registry. We adjusted populations using a time-dependent propensity score matching. Analyses were stratified according to patient's first rhythm. After matching, 2837 pairs of patients with a shockable rhythm were created and 20,950 with a nonshockable rhythm.

RESULTS

Whatever the patient's rhythm (shockable or nonshockable), epinephrine use was associated with less D30 survival (odds ratio [OR] 0.508; 95% confidence interval [CI] 0.440-0.586] and OR 0.645; 95% CI 0.549-0.759, respectively). In shockable rhythms, on all outcomes, epinephrine use was deleterious. In nonshockable rhythms, no difference was observed regarding return of spontaneous circulation and survival at hospital admission. However, epinephrine use was associated with worse neurological prognosis (OR 0.646; 95% CI 0.549-0.759).

CONCLUSIONS

In shockable and nonshockable rhythms, epinephrine does not seem to have any benefit on D30 survival. These results underscore the need to perform further studies to define the optimal conditions for using epinephrine in patients with OHCA.

Effects of different adrenaline doses on cerebral oxygenation and cerebral metabolism during cardiopulmonary resuscitation in pigs

BACKGROUND

The influence of adrenaline during cardiopulmonary resuscitation (CPR) on the neurological outcome of cardiac arrest survivors is unclear. As little is known about the pathophysiological effects of adrenaline on cerebral oxygen delivery and cerebral metabolism we investigated its effects on parameters of cerebral oxygenation and cerebral metabolism in a pig model of CPR.

METHODS

Fourteen pigs were anesthetized, intubated and instrumented. After 5 min of cardiac arrest CPR was started and continued for 15 min. Animals were randomized to receive bolus injections of either 15 or 30 μg/kg adrenaline every 5 min after commencement of CPR.

RESULTS

Measurements included mean arterial pressure (MAP), intracranial pressure (ICP), cerebral perfusion pressure (CPP), cerebral regional oxygen saturation (rSO₂), brain tissue oxygen tension (P_btO₂), arterial and cerebral venous blood gases and cerebral microdialysis parameters, e.g. lactate/pyruvate ratio. Adrenaline induced a significant increase in MAP and CPP in all pigs. However, increases in MAP and CPP were short-lasting and tended to decrease with repetitive bolus administration. There was no statistical difference in any parameter of cerebral oxygenation or metabolism between study groups.

CONCLUSIONS

Both adrenaline doses resulted in short-lasting CPP peaks which did not translate into improved cerebral tissue oxygen tension and metabolism. Further studies are needed to determine whether other dosing regimens targeting a sustained increase in CPP, may lead to improved brain oxygenation and metabolism, thereby improving neurological outcome of cardiac arrest patients.

Pralidoxime-Induced Potentiation of the Pressor Effect of Adrenaline and Hastened Successful Resuscitation by Pralidoxime in a Porcine Cardiac Arrest Model

PURPOSE

Pralidoxime potentiated the pressor effect of adrenaline and facilitated restoration of spontaneous circulation (ROSC) after prolonged cardiac arrest. In this study, we hypothesised that pralidoxime would hasten ROSC in a model with a short duration of untreated ventricular fibrillation (VF). We also hypothesised that potentiation of the pressor effect of adrenaline by pralidoxime would not be accompanied by worsening of the adverse effects of adrenaline.

METHODS

After 5 min of VF, 20 pigs randomly received either pralidoxime (40 mg/kg) or saline, in combination with adrenaline, during cardiopulmonary resuscitation (CPR). Coronary perfusion pressure (CPP) during CPR, and ease of resuscitation were compared between the groups. Additionally, haemodynamic data, severity of ventricular arrhythmias, and cerebral microcirculation were measured during the 1-h post-resuscitation period. Cerebral microcirculatory blood flow and brain tissue oxygen tension (PbtO₂) were measured on parietal cortices exposed through burr holes.

RESULTS

All animals achieved ROSC. The pralidoxime group had higher CPP during CPR (P = 0.014) and required a shorter duration of CPR (P = 0.024) and smaller number of adrenaline doses (P = 0.024). During the post-resuscitation period, heart rate increased over time in the control group, and decreased steadily in the pralidoxime group. No inter-group differences were observed in the incidences of ventricular arrhythmias, cerebral microcirculatory blood flow, and PbtO₂.

CONCLUSION

Pralidoxime improved CPP and hastened ROSC in a model with a short duration of untreated VF. The potentiation of the pressor effect of adrenaline was not accompanied by the worsening of the adverse effects of adrenaline.

Epinephrine treatment but not time to ROSC is associated with intestinal injury in patients with cardiac arrest

AIM

Current guidelines suggest the use of epinephrine in patients with cardiac arrest (CA). However, evidence for increased survival in good neurological condition is lacking. In experimental settings, epinephrine-induced impairment of microvascular flow was shown. The aim of our study was to analyze the association between epinephrine treatment and intestinal injury in patients after CA.

METHODS

We have included 52 patients with return of spontaneous circulation (ROSC) after CA admitted to our medical intensive care unit (ICU). Blood was taken on admission and levels of circulating intestinal fatty acid binding protein (iFABP) were analyzed.

RESULTS

Patients were 64 (49.8-73.8) years old and predominantly male (76.9%). After six months, 50% of patients died and 38.5% of patients had a cerebral performance category (CPC)-score of 1-2. iFABP levels were lower in survivors (234 IQR 90-399 pg/mL) as compared to non-survivors (283, IQR 86-11500 pg/mL; p < 0.05). Plasma levels of iFABP were not associated with time to ROSC but correlated with epinephrine-dose (R = 0.32; p < 0.05). 40% of patients receiving ≥3 mg of epinephrine as compared to 10.5% of patients treated with <3 mg (p < 0.05) developed iFABP plasma levels >1500 pg/mL, which was associated with dramatically increased mortality (HR4.87, 95%CI 1.95-12.1; p < 0.001). iFABP levels predicted mortality independent from time to ROSC and the disease severity score SAPS II. In contrast to mortality, iFABP plasma levels were not associated with neurological outcome.

CONCLUSIONS

In this small, single centre study, cumulative dose of epinephrine used in cardiac arrest patients was associated with an increase in biomarker indicative of intestinal injury and 6-month mortality.

Effects of Different Doses of Pralidoxime Administered During Cardiopulmonary Resuscitation and the Role of α-Adrenergic Receptors in Its Pressor Action

Background

We previously reported that pralidoxime facilitated restoration of spontaneous circulation by potentiating the pressor effect of epinephrine. We determined the optimal dose of pralidoxime during cardiopulmonary resuscitation and evaluated the involvement of α‐adrenoceptors in its pressor action.

Methods and Results

Forty‐four pigs randomly received 1 of 3 doses of pralidoxime (40, 80, or 120 mg/kg) or saline placebo during cardiopulmonary resuscitation, including epinephrine administration. Pralidoxime at 40 mg/kg produced the highest coronary perfusion pressure, whereas 120 mg/kg of pralidoxime produced the lowest coronary perfusion pressure. Restoration of spontaneous circulation was attained in 4 (36.4%), 11 (100%), 9 (81.8%), and 3 (27.3%) animals in the saline, 40, 80, and 120 mg/kg groups, respectively (P<0.001). In 49 rats, arterial pressure response to 40 mg/kg of pralidoxime was determined after saline, guanethidine, phenoxybenzamine, or phentolamine pretreatment, and the response to 200 mg/kg pf pralidoxime was determined after saline, propranolol, or phentolamine pretreatment. Pralidoxime at 40 mg/kg elicited a pressor response. Phenoxybenzamine completely inhibited the pressor response, but guanethidine and phentolamine did not. The pressor response of pralidoxime was even greater after guanethidine or phentolamine pretreatment. Pralidoxime at 200 mg/kg produced an initial vasodepressor response followed by a delayed pressor response. Unlike propranolol, phentolamine eliminated the initial vasodepressor response.

Conclusions

Pralidoxime at 40 mg/kg administered with epinephrine improved restoration of spontaneous circulation rate by increasing coronary perfusion pressure in a pig model of cardiac arrest, whereas 120 mg/kg did not improve coronary perfusion pressure or restoration of spontaneous circulation rate. The pressor effect of pralidoxime was unrelated to α‐adrenoceptors and buffered by its vasodepressor action mediated by sympathoinhibition.

Effects of Polyethylene Glycol-20k on Coronary Perfusion Pressure and Postresuscitation Myocardial and Cerebral Function in a Rat Model of Cardiac Arrest

Background Epinephrine increases the rate of return of spontaneous circulation. However, it increases severity of postresuscitation myocardial and cerebral dysfunction and reduces duration of survival. We investigated the effects of aortic infused polyethylene glycol, 20 000 molecular weight (PEG-20k) during cardiopulmonary resuscitation on coronary perfusion pressure, postresuscitation myocardial and cerebral function, and duration of survival in a rat model of cardiac arrest. Methods and Results Twenty-four male rats were randomized into 4 groups: (1) PEG-20k, (2) epinephrine, (3) saline control-intravenous, and (4) saline control-intra-aortic. Cardiopulmonary resuscitation was initiated after 6 minutes of untreated ventricular fibrillation. In PEG-20k and Saline-A, either PEG-20k (10% weight/volume in 10% estimated blood volume infused over 3 minutes) or saline was administered intra-aortically after 4 minutes of precordial compression. In epinephrine and placebo groups, either epinephrine (20 μg/kg) or saline placebo was administered intravenously after 4 minutes of precordial compression. Resuscitation was attempted after 8 minutes of cardiopulmonary resuscitation. Sublingual microcirculation was measured at baseline and 1, 3, and 5 hours after return of spontaneous circulation. Myocardial function was measured at baseline and 2, 4, and 6 hours after return of spontaneous circulation. Neurologic deficit scores were recorded at 24, 48, and 72 hours after return of spontaneous circulation. Aortic infusion of PEG-20k increased coronary perfusion pressure to the same extent as epinephrine. Postresuscitation sublingual microcirculation, myocardial and cerebral function, and duration of survival were improved in PEG-20k (P<0.05) compared with epinephrine (P<0.05). Conclusions Aortic infusion of PEG-20k during cardiopulmonary resuscitation increases coronary perfusion pressure to the same extent as epinephrine, improves postresuscitation myocardial and cerebral function, and increases duration of survival in a rat model of cardiac arrest.

Pralidoxime administered during cardiopulmonary resuscitation facilitates successful resuscitation in a pig model of cardiac arrest

Pralidoxime is a common antidote for organophosphate poisoning; however, studies have also reported pralidoxime's pressor effect, which may facilitate the restoration of spontaneous circulation (ROSC) after cardiac arrest by improving coronary perfusion pressure (CPP). We investigated the immediate cardiovascular effects of pralidoxime in anaesthetised normal rats and the effects of pralidoxime administration during cardiopulmonary resuscitation (CPR) in a pig model of cardiac arrest. To evaluate the immediate cardiovascular effects of pralidoxime, seven anaesthetised normal rats received saline or pralidoxime (20 mg/kg) in a randomised crossover design, and the responses were determined using the conductance catheter technique. To evaluate the effects of pralidoxime administration during CPR, 22 pigs randomly received either 80 mg/kg of pralidoxime or an equivalent volume of saline during CPR. In the rats, pralidoxime significantly increased arterial pressure than saline (P = .044). The peak effect on arterial pressure was observed in the first minute. In a pig model of cardiac arrest, CPP during CPR was higher in the pralidoxime group than in the control group (P = .002). ROSC was attained in three animals (27.3%) in the control group and nine animals (81.8%) in the pralidoxime group (P = .010). Three animals (27.3%) in the control group and eight animals (72.2%) in the pralidoxime group survived the 6-hour period (P = .033). In conclusion, pralidoxime had a rapid onset of pressor effect. Pralidoxime administered during CPR led to significantly higher rates of ROSC and 6-hour survival by improving CPP in a pig model.

Effects of epinephrine for out-of-hospital cardiac arrest: A systematic review and meta-analysis of randomized controlled trials

AIM

Our objective is to assess the effects of epinephrine for out of hospital cardiac arrest.

BACKGROUND

Cardiac arrest was the most serious medical incidents with an estimated incidence in the United States of 95.7 per 100,000 person years. Though epinephrine improved coronary and cerebral perfusion, improving a return of spontaneous circulation, potentially harmful effects on the heart lead to greater myocardial oxygen demand. Concerns about the effect of epinephrine for out-of-hospital cardiac arrest were controversial and called for a higher argument to determine whether the effects of epinephrine is safe and effective for shor and long terms outcomes.

METHOD

Searching databases consist of all kinds of searching tools, such as Medline, the Cochrane Library, Embase, PubMed, etc. All the included studies should meet our demand of this meta-analysis. In the all interest outcomes blow we take the full advantage of STATA to assess, the main measure is Risk Ratio (RR) with 95% confidence, the publication bias are assessed by Egger Test.

RESULT

In current systematic review and meta-analysis of randomized trials investigating epinephrine for out of hospital cardiac arrest, we found that epinephrine was associated with a significantly higher likelihood of ROSC (RR = 3.05, I = 23.1%, P = .0001) and survival to hospital discharge (RR = 1.40, I = 36.3%, P = .008) compared with non-adrenaline administration. Conversely, epinephrine did not increase CPC 1 or 2 (RR = 1.15, I = 40.5%, P = .340) and hospital admission (RR = 2.07, I = 88.2%, P = .0001).

CONCLUSION

In conclusion, in this systematic review and meta-analysis involving studies, the use of epinephrine resulted in a significantly higher likelihood of survival to hospital discharge and ROSC than the non-epinephrine administration, but, there was no significant between group difference in the rate of a favorable neurologic outcome.

Vasopressors During Cardiopulmonary Resuscitation. A Network Meta-Analysis of Randomized Trials

OBJECTIVES

Several randomized controlled trials have compared adrenaline (epinephrine) with alternative therapies in patients with cardiac arrest with conflicting results. Recent observational studies suggest that adrenaline might increase return of spontaneous circulation but worsen neurologic outcome. We systematically compared all the vasopressors tested in randomized controlled trials in adult cardiac arrest patients in order to identify the treatment associated with the highest rate of return of spontaneous circulation, survival, and good neurologic outcome.

DESIGN

Network meta-analysis.

PATIENTS

Adult patients undergoing cardiopulmonary resuscitation.

INTERVENTIONS

PubMed, Embase, BioMed Central, and the Cochrane Central register were searched (up to April 1, 2017). We included all the randomized controlled trials comparing a vasopressor with any other therapy. A network meta-analysis with a frequentist approach was performed to identify the treatment associated with the highest likelihood of survival.

MEASUREMENTS AND MAIN RESULTS

Twenty-eight studies randomizing 14,848 patients in 12 treatment groups were included. Only a combined treatment with adrenaline, vasopressin, and methylprednisolone was associated with increased likelihood of return of spontaneous circulation and survival with a good neurologic outcome compared with several other comparators, including adrenaline. Adrenaline alone was not associated with any significant difference in mortality and good neurologic outcome compared with any other comparator.

CONCLUSIONS

In randomized controlled trials assessing vasopressors in adults with cardiac arrest, only a combination of adrenaline, vasopressin, and methylprednisolone was associated with improved survival with a good neurologic outcome compared with any other drug or placebo, particularly in in-hospital cardiac arrest. There was no significant randomized evidence to support neither discourage the use of adrenaline during cardiac arrest.

Levels of Catecholamines in the Plasma of Patients with Cardiopulmonary Arrest

So far, there remains a controversy regarding the efficacy of epinephrine (Ep) in patients with cardiopulmonary arrest (CPA). In this study, we evaluated the importance of the plasma levels of catecholamines prior to the administration of Ep in patients with CPA. Patients with out-of-hospital cardiac arrest (OHCA) who were transferred to Gunma University Hospital were enrolled prospectively between July 2014 and July 2017. The levels of catecholamines [Ep, norepinephrine (NEp), and dopamine] and vasopressin (antidiuretic hormone) in the plasma were measured using blood samples of cardiogenic patients with OHCA not treated with Ep. Patients were divided into two groups: the return of spontaneous circulation [ROSC (+) ] group and the no return of spontaneous circulation [ROSC (-) ] group. The plasma levels of these agents and the conditions of resuscitation were compared between these two groups. 48 patients with cardiogenic CPA had not been treated with Ep prior to obtaining the blood samples. The ROSC (+) and ROSC (-) groups included 14 and 34 patients, respectively. The frequency of prehospital defibrillation was significantly higher in the ROSC (+) group. However, the prehospital resuscitation time was significantly shorter in the ROSC (+) group. Moreover, the levels of Ep and NEp in the plasma were significantly lower in the ROSC (+) group. The increased levels of Ep in the plasma may not be associated with the acquisition of ROSC in patients with cardiogenic CPA.

Study of the Effects of Epinephrine on Cerebral Oxygenation and Metabolism During Cardiac Arrest and Resuscitation by Hyperspectral Near-Infrared Spectroscopy

OBJECTIVES

Epinephrine is routinely administered to sudden cardiac arrest patients during resuscitation, but the neurologic effects on patients treated with epinephrine are not well understood. This study aims to assess the cerebral oxygenation and metabolism during ventricular fibrillation cardiac arrest, cardiopulmonary resuscitation, and epinephrine administration.

DESIGN

To investigate the effects of equal dosages of IV epinephrine administrated following sudden cardiac arrest as a continuous infusion or successive boluses during cardiopulmonary resuscitation, we monitored cerebral oxygenation and metabolism using hyperspectral near-infrared spectroscopy.

SETTINGS

A randomized laboratory animal study.

SUBJECTS

Nine healthy pigs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Our study showed that although continuous epinephrine administration had no significant impact on overall cerebral hemodynamics, epinephrine boluses transiently improved cerebral oxygenation (oxygenated hemoglobin) and metabolism (cytochrome c oxidase) by 15% ± 6.7% and 49% ± 18%, respectively (p < 0.05) compared with the baseline (untreated) ventricular fibrillation. Our results suggest that the effects of epinephrine diminish with successive boluses as the impact of the third bolus on brain oxygen metabolism was 24.6% ± 3.8% less than that of the first two boluses.

CONCLUSIONS

Epinephrine administration by bolus resulted in transient improvements in cerebral oxygenation and metabolism, whereas continuous epinephrine infusion did not, compared with placebo. Future studies are needed to evaluate and optimize the use of epinephrine in cardiac arrest resuscitation, particularly the dose, timing, and mode of administration.