Prophylactic lidocaine for post resuscitation care of patients with out-of-hospital ventricular fibrillation cardiac arrest

Background

Antiarrhythmic drugs like lidocaine are usually given to promote return of spontaneous circulation (ROSC) during ongoing out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation/tachycardia (VF/VT). Whether administering such drugs prophylactically for post-resuscitation care after ROSC prevents re-arrest and improves outcome is unstudied.

Methods

We evaluated a cohort of 1721 patients with witnessed VF/VT OHCA who did (1296) or did not receive prophylactic lidocaine (425) at first ROSC. Study endpoints included re-arrest, hospital admission and survival.

Results

Prophylacic lidocaine recipients and non-recipients were comparable, except for shorter time to first ROSC and higher systolic blood pressure at ROSC in those receiving lidocaine. After initial ROSC, arrest from VF/VT recurred in 16.7% and from non-shockable arrhythmias in 3.2% of prophylactic lidocaine recipients, 93.5% of whom were admitted to hospital and 62.4% discharged alive, as compared with 37.4%, 7.8%, 84.9% and 44.5%, of corresponding non-recipients (all p < 0.0001). Adjusted for pertinent covariates, prophylactic lidocaine was independently associated with reduced odds of re-arrest from VF/VT, odds ratio, (95% confidence interval) 0.34 (0.26–0.44) and from nonshockable arrhythmias (0.47 (0.29–0.78)); a higher hospital admission rate (1.88, (1.28–2.76)) and improved survival to discharge (1.49 (1.15–1.95)). However in a propensity score-matched sensitivity analysis, lidocaine's only beneficial association with outcome was in a lower incidence of recurrent VF/VT arrest.

Conclusions

Administration of prophylactic lidocaine upon ROSC after OHCA was consistently associated with less recurrent VF/VT arrest, and therapeutic equipoise for other measures. The prospect of a promising association between lidocaine prophylaxis and outcome, without evidence of harm, warrants further investigation.     

Comparison of the efficacy of nifekalant and amiodarone in a porcine model of cardiac arrest

Objective

To compare the efficacy of nifekalant and amiodarone in the treatment of cardiac arrest in a porcine model.

Methods

After 4 min of untreated ventricular fibrillation, animals were randomly treated with nifekalant (2 mg kg⁻¹), amiodarone (5 mg kg⁻¹) or saline placebo (n = 12 pigs per group). Precordial compression and ventilation were initiated after drug administration and defibrillation was attempted 2 min later. Hemodynamics were continuously measured for 6 h after successful resuscitation.

Results

Compared with saline, nifekalant and amiodarone equally decreased the number of electric shocks, defibrillation energy, epinephrine dose, and duration of cardiopulmonary resuscitation required for successful resuscitation (P < 0.01). The incidence of restoration of spontaneous circulation (ROSC) and the 24-h survival rate were higher in both antiarrhythmic drug groups (P < 0.05) vs. the saline group. Furthermore, post-resuscitation myocardial dysfunction at 4-6 h after successful resuscitation was improved in animals given antiarrhythmic drugs as compared with the saline group (P < 0.05). There were no differences between nifekalant and amiodarone for any of these parameters.

Conclusion

The effect of nifekalant was similar to that of amiodarone for improving defibrillation efficacy and for the treatment of cardiac arrest. Administration of either nifekalant or amiodarone before defibrillation increased the ROSC and 24-h survival rates and improved post-resuscitation cardiac function in this porcine model.     

A pilot study examining the role of regional cerebral oxygen saturation monitoring as a marker of return of spontaneous circulation in shockable (VF/VT) and non-shockable (PEA/Asystole) causes of cardiac arrest

Background

Non-invasive monitoring of cerebral perfusion and oxygen delivery during cardiac arrest is not routinely utilized during cardiac arrest resuscitation. The objective of this study was to investigate the feasibility of using cerebral oximetry during cardiac arrest and to determine the relationship between regional cerebral oxygen saturation (rSO2) with return of spontaneous circulation (ROSC) in shockable (VF/VT) and non-shockable (PEA/asystole) types of cardiac arrest.

Methods

Cerebral oximetry was applied to 50 in-hospital and out-of-hospital cardiac arrest patients.

Results

Overall, 52% (n = 26) achieved ROSC and 48% (n = 24) did not achieve ROSC. There was a significant difference in mean ± SD rSO2% in patients who achieved ROSC compared to those who did not (47.2 ± 10.7% vs. 31.7 ± 12.8%, p < 0.0001). This difference was observed during asystole (median rSO2 (IQR) ROSC versus no ROSC: 45.0% (35.1–48.8) vs. 24.9% (20.5–32.9), p < 0.002) and PEA (50.6% (46.7–57.5) vs. 31.6% (18.8–43.3), p = 0.02), but not in the VF/VT subgroup (43.7% (41.1–54.7) vs. 42.8% (34.9–45.0), p = 0.63). Furthermore, it was noted that no subjects with a mean rSO2 < 30% achieved ROSC.

Conclusions

Cerebral oximetry may have a role as a real-time, non-invasive predictor of ROSC during cardiac arrest. The main utility of rSO2 in determining ROSC appears to apply to asystole and PEA subgroups of cardiac arrest, rather than VF/VT. This observation may reflect the different physiological factors involved in recovery from PEA/asytole compared to VF/VT. Whereas in VF/VT, successful defibrillation is of prime importance, however in PEA and asytole achieving ROSC is more likely to be related to the quality of oxygen delivery. Furthermore, a persistently low rSO2 <30% in spite of optimal resuscitation methods may indicate futility of resuscitation efforts.     

Minimizing pre- and post-defibrillation pauses increases the likelihood of return of spontaneous circulation (ROSC)

Background

The three-phase model of ventricular fibrillation (VF) arrest suggests a period of compressions to “prime” the heart prior to defibrillation attempts. In addition, post-shock compressions may increase the likelihood of return of spontaneous circulation (ROSC). The optimal intervals for shock delivery following cessation of compressions (pre-shock interval) and resumption of compressions following a shock (post-shock interval) remain unclear.

Objective

To define optimal pre- and post-defibrillation compression pauses for out-of-hospital cardiac arrest (OOHCA).

Methods

All patients suffering OOHCA from VF were identified over a 1-month period. Defibrillator data were abstracted and analyzed using the combination of ECG, impedance, and audio recording. Receiver-operator curve (ROC) analysis was used to define the optimal pre- and post-shock compression intervals. Multiple logistic regression analysis was used to quantify the relationship between these intervals and ROSC. Covariates included cumulative number of defibrillation attempts, intubation status, and administration of epinephrine in the immediate pre-shock compression cycle. Cluster adjustment was performed due to the possibility of multiple defibrillation attempts for each patient.

Results

A total of 36 patients with 96 defibrillation attempts were included. The ROC analysis identified an optimal pre-shock interval of <3 s and an optimal post-shock interval of <6 s. Increased likelihood of ROSC was observed with a pre-shock interval <3 s (adjusted OR 6.7, 95% CI 2.0-22.3, p = 0.002) and a post-shock interval of <6 s (adjusted OR 10.7, 95% CI 2.8-41.4, p = 0.001). Likelihood of ROSC was substantially increased with the optimization of both pre- and post-shock intervals (adjusted OR 13.1, 95% CI 3.4-49.9, p < 0.001).

Conclusions

Decreasing pre- and post-shock compression intervals increases the likelihood of ROSC in OOHCA from VF.     

Changing EMS dispatcher CPR instructions to 400 compressions before mouth-to-mouth improved bystander CPR rates

Background

To examine the impact of changing dispatcher CPR instructions (400 compressions: 2 breaths, followed by 100:2 ratio) on rates of bystander CPR and survival in adults with presumed cardiac out-of-hospital arrest (OHCA) in Melbourne, Australia.

Methods

The Victorian Ambulance Cardiac Arrest Registry (VACAR) was searched for OHCA where Emergency Medical Services (EMS) attempted CPR between August 2006 and August 2009. OHCA included were: (1) patients aged ≥18 years old; (2) presumed cardiac etiology; and (3) not witnessed by EMS.

Results

For the pre- and post-study periods, 1021 and 2101 OHCAs met inclusion criteria, respectively. Rates of bystander CPR increased overall (45-55%, p < 0.001) and by initial rhythm (shockable 55-70%, p < 0.001 and non-shockable 40-46%, p = 0.01). In VF/VT OHCA, there were improvements in the number of patients arriving at hospital with a return of spontaneous circulation (ROSC) (48-56%, p = 0.02) and in survival to hospital discharge (21-29%, p = 0.002), with improved outcomes restricted to patients receiving bystander CPR. After adjusting for factors associated with survival, the period of time following the change in CPR instructions was a significant predictor of survival to hospital discharge in VF/VT patients (OR 1.57, 95% CI: 1.15-2.20, p = 0.005).

Conclusion

Following changes to dispatcher CPR instructions, significant increases were seen in rates of bystander CPR and improvements were seen in survival in VF/VT patients who received bystander CPR, after adjusting for factors associated with survival.     

Performance of a rectilinear biphasic waveform in defibrillation of presenting and recurrent ventricular fibrillation: a prospective multicenter study

Objectives

We tested the hypothesis that shock success differs with initial and recurrent episodes of ventricular fibrillation (VF).

Methods

From September 2008 to March 2010 out-of-hospital cardiac arrest patients with VF as the initial rhythm at 9 study sites were defibrillated by paramedics using a rectilinear biphasic waveform. Shock success was defined as termination of VF within 5 s post-shock. We used generalized estimating equation (GEE) analysis to assess the association between shock type (initial versus refibrillation) and shock success.

Results

Ninety-four patients presented in VF. Mean age was 65.4 years, 78.7% were male, and 80.9% were bystander-witnessed. VF recurred in 75 (79.8%). There were 338 shocks delivered for initial (n = 90) or recurrent (n = 248) VF available for analysis. Initial shocks terminated VF in 79/90 (87.8%) and subsequent shocks in 209/248 (84.3%). GEE odds ratio (OR) for shock type was 1.37 (95% CI 0.68-2.74). After adjusting for potential confounders, the OR for shock type remained insignificant (1.33, 95% CI 0.60-2.53). We observed no significant difference in ROSC (54.7% versus 52.6%, absolute difference 2.1%, p = 0.87) or neurologically intact survival to hospital discharge (21.9% versus 33.3%, absolute difference 11.4%, p = 0.31) between those with and without VF recurrence.

Conclusions

Presenting VF was terminated with one shock in 87.8% of cases. We observed no significant difference in the frequency of shock success between initial versus recurrent VF. VF recurred in the majority of patients and did not adversely affect shock success, ROSC, or survival.     

Prognostic indicators and outcome prediction model for patients with return of spontaneous circulation from cardiopulmonary arrest: the Utstein Osaka Project

Objective

To determine the most important indicators of prognosis in patients with return of spontaneous circulation (ROSC) following out-of-hospital cardiopulmonary arrest (OHCA) and to develop a best outcome prediction model.

Design and patients

All patients were prospectively recorded based on the Utstein Style in Osaka over a period of 3 years (2005-2007). Criteria for inclusion were a witnessed cardiac arrest, age greater than 17 years, presumed cardiac origin of the arrest, and successful ROSC. Multivariate logistic regression (MLR) analysis was used to develop the best prediction model. The dependent variables were favourable outcome (cerebral-performance category [CPC]: 1-2) and poor outcome (CPC: 3-5) at 1 month after the event. Eight explanatory pre-hospital variables were used concerning patient characteristics and resuscitation. External validation was performed on an independent set of Utstein data in 2007.

Results

Subjects comprised 285 patients in VF and 577 patients with pulseless electrical activity (PEA)/asystole. The percentage of favourable outcomes was 31.9% (91/285) in VF and 5.7% (33/577) in PEA/asystole. The most important prognostic indicators of favourable outcome found by MLR were age (p = 0.10), time from collapse to ROSC (TROSC) (p < 0.01), and presence of pre-hospital ROSC (PROSC) (p = 0.15) for VF and age (p = 0.03), TROSC (p < 0.01), PROSC (p < 0.01), and conversion to VF (p = 0.01) for PEA/asystole. For external validation data, areas under the receiver-operating characteristic curve were 0.867 for VF and 0.873 for PEA/asystole.

Conclusions

A model based on four selected indicators showed a high predictive value for favourable outcome in OHCA patients with ROSC.     

Optimal loop duration during the provision of in-hospital advanced life support (ALS) to patients with an initial non-shockable rhythm

Background

In advanced life support (ALS), time-cycled “loops” of chest compressions form the basis of action. However, the provider must compromise between interrupting compressions and detecting a change in cardiac rhythm. An “optimal” loop duration would best balance these choices. The current international CPR guidelines recommend 2-min loop durations. The aim of this study was to investigate the “optimal” loop duration in patients with initial asystole or pulseless electrical activity (PEA).

Materials and methods

Detailed defibrillator recordings from 249 in-hospital cardiac arrests at the University of Chicago Medicine (Chicago, IL) and St. Olav University Hospital (Trondheim, Norway) were analysed. The clinical states of asystole, PEA, ventricular fibrillation/-tachycardia (VF/VT) and return of spontaneous circulation (ROSC) were annotated along the time axis. PEA and asystole were combined as a single state for the analysis of state development. The probability of staying in PEA/asystole over time was estimated non-parametrically. In addition, to distinguish between initial and secondary PEA/asystole, the latter was defined by the transition from VF/VT or ROSC.

Results

Among patients with initial PEA (n = 179), 25% and 50% of patients had left PEA/asystole after 4 and 9 min of ALS efforts, respectively. The corresponding time points for patients with initial asystole (n = 70) were 7.3 and 13.3 min, respectively. The probability of transition from secondary PEA/asystole to ROSC or VF/VT varied between 10% and 20% in each 2–4 min interval.

Conclusion

The “optimal” first loop duration may be 4 min in initial PEA and 6–8 min in initial asystole. If secondary PEA/asystole is encountered, 2-min loop duration seems appropriate.     

A model of survival from out-of-hospital cardiac arrest using the Boston EMS arrest registry

Objectives

To characterize the survival rate for out-of-hospital arrests of cardiac aetiology and predictor variables associated with survival in Boston, MA, and to develop a composite multivariate logistic regression model for projecting survival rates.

Methods

This is a retrospective analysis of all arrests of presumed cardiac aetiology (from January 1, 2004 to December 31, 2007) where resuscitation was attempted (n = 1156) by 911 emergency responders.

Results

The survival-at-hospital discharge rate was 11% (vs. 1-10% often reported). The coefficients and odds ratios in the first equation of the model show that joint presence of presenting rhythm of ventricular fibrillation/tachycardia (VF/VT) and return of spontaneous circulation in the pre-hospital setting (ROSC) is a substantial direct predictor of survival (e.g., 54% of such cases survive). Response time, public location, witnessed, and age are significant but less sizable direct predictors of survival. A second equation shows that these four variables make an additional indirect contribution to survival by affecting the probability of joint presence of VF/VT and ROSC; bystander CPR also makes such an indirect contribution but no significant direct one as shown in the first equation. The projected survival rate if cases had always experienced bystander CPR and rapid response time of less than four minutes is 21%.

Conclusions

The unique model describes the major contribution of VF/VT and ROSC, and key relationships among predictors of survival. These connections may have otherwise gone underreported using standard approaches and should be considered when allocating scarce resources to impact cardiac arrest survival.     

The use of antiarrhythmic drugs for adult cardiac arrest: a systematic review

Aims

In adult cardiac arrest, antiarrhythmic drugs are frequently utilized in acute management and legions of medical providers have memorized the dosage and timing of administration. However, data supporting their use is limited and is the focus of this comprehensive review.

Methods

Databases including PubMed, Cochrane Library (including Cochrane database for systematic reviews and Cochrane Central Register of Controlled Trials), Embase, and AHA EndNote Master Library were systematically searched. Further references were gathered from cross-references from articles and reviews as well as forward search using SCOPUS and Google scholar. The inclusion criteria for this review included human studies of adult cardiac arrest and anti-arrhythmic agents, peer-review. Excluded were review articles, case series and case reports.

Results

Of 185 articles found, only 25 studies met the inclusion criteria for further review. Of these, 9 were randomised controlled trials. Nearly all trials solely evaluated Ventricular Tachycardia (VT) and Ventricular Fibrillation (VF), and excluded Pulseless Electrical Activity (PEA) and asystole. In VT/VF patients, amiodarone improved survival to hospital admission, but not to hospital discharge when compared to lidocaine in two randomized controlled trials.

Conclusion

Amiodarone may be considered for those who have refractory VT/VF, defined as VT/VF not terminated by defibrillation, or VT/VF recurrence in out of hospital cardiac arrest or in-hospital cardiac arrest. There is inadequate evidence to support or refute the use of lidocaine and other antiarrythmic agents in the same settings.     

Clinical state transitions during advanced life support (ALS) in in-hospital cardiac arrest

Background

When providing advanced life support (ALS) in cardiac arrest, the patient may alternate between four clinical states: ventricular fibrillation/tachycardia (VF/VT), pulseless electrical activity (PEA), asystole, and return of spontaneous circulation (ROSC). At the end of the resuscitation efforts, either death has been declared or sustained ROSC has been obtained. The aim of this study was to describe and analyze the clinical state transitions during ALS among patients experiencing in-hospital cardiac arrest.

Methods and results

The defibrillator files from 311 in-hospital cardiac arrests at the University of Chicago Hospital (IL, USA) and St. Olav University Hospital (Trondheim, Norway) were analyzed (clinicaltrials.gov: NCT00920244). The transitions between clinical states were annotated along the time axis and visualized as plots of the state prevalence according to time. The cumulative intensity of the state transitions was estimated by the Nelson–Aalen estimator for each type of state transition, and for the intensities of overall state transitions. Between 70% and 90% of patients who eventually obtained sustained ROSC had progressed to ROSC by approximately 15–20 min of ALS, depending on the initial rhythm. Patients behaving unstably after this time period, i.e., alternating between ROSC, VF/VT and PEA, had a high risk of ultimately being declared dead.

Conclusions

We provide an overall picture of the intensities and patterns of clinical state transitions during in-hospital ALS. The majority of patients who obtained sustained ROSC obtained this state and stabilized within the first 15–20 min of ALS. Those who continued to behave unstably after this time point had a high risk of ultimately being declared dead.     

Predictors of resuscitation outcome in a swine model of VF cardiac arrest: A comparison of VF duration,presence of acute myocardial infarction and VF waveform

Introduction

Factors that affect resuscitation to a perfusing rhythm (ROSC) following ventricular fibrillation (VF) include untreated VF duration, acute myocardial infarction (AMI), and possibly factors reflected in the VF waveform. We hypothesized that resuscitation of VF to ROSC within 3 min is predicted by the VF waveform, independent of untreated VF duration or presence of acute MI.

Methods

AMI was induced by the occlusion of the left anterior descending coronary artery. VF was induced in normal (N = 30) and AMI swine (N = 30). Animals were resuscitated after untreated VF of brief (2 min) or prolonged (8 min) duration. VF waveform was analyzed before the first shock to compute the amplitude-spectral area (AMSA) and slope.

Results

Unadjusted predictors of ROSC within 3 min included untreated VF duration (8 min vs 2 min; OR 0.11, 95%CI 0.02–0.54), AMI (AMI vs normal; OR 0.11, 95%CI 0.02–0.54), AMSA (highest to lowest tertile; OR 15.5, 95%CI 1.7–140), and slope (highest to lowest tertile; OR 12.7, 95%CI 1.4–114). On multivariate regression, untreated VF duration (P = 0.011) and AMI (P = 0.003) predicted ROSC within 3 min. Among secondary outcome variables, favorable neurological status at 24 h was only predicted by VF duration (OR 0.22, 95% CI 0.05–0.92).

Conclusions

In this swine model of VF, untreated VF duration and AMI were independent predictors of ROSC following VF cardiac arrest. AMSA and slope predicted ROSC when VF duration or the presence of AMI were unknown. Importantly, the initial treatment of choice for short duration VF is defibrillation regardless of VF waveform.     

Treatment of monitored out-of-hospital ventricular fibrillation and pulseless ventricular tachycardia utilising the precordial thump

Background

Few studies have described the value of the precordial thump (PT) as first-line treatment of monitored out-of-hospital cardiac arrest (OHCA) from ventricular fibrillation and pulseless ventricular tachycardia (VF/VT).

Methods

Patient data was extracted from the Victorian Ambulance Cardiac Arrest Registry (VACAR) for all OHCA witnessed by paramedics between 2003 and 2011. Adult patients who suffered a monitored VF/VT of presumed cardiac aetiology were included. Cases were excluded if the arrest occurred after arrival at hospital, or a ‘do not resuscitate’ directive was documented. Patients were assigned into two groups according to the use of the PT or defibrillation as first-line treatment. The study outcomes were: impact of first shock/thump on return of spontaneous circulation (ROSC), overall ROSC, and survival to hospital discharge.

Results

A total of 434 cases met the eligibility criteria, of which first-line treatment involved a PT in 103 (23.7%) and immediate defibrillation in 325 (74.8%) cases. Patient characteristics did not differ significantly between groups. Seventeen patients (16.5%) observed a PT-induced rhythm change, including five cases of ROSC and 10 rhythm deteriorations. Immediate defibrillation resulted in significantly higher levels of immediate ROSC (57.8% vs. 4.9%, p < 0.0001), without excess rhythm deteriorations (12.3% vs. 9.7%, p = 0.48). Of the five successful PT attempts, three required defibrillation following re-arrest. Overall ROSC and survival to hospital discharge did not differ significantly between groups.

Conclusion

The PT used as first-line treatment of monitored VF/VT rarely results in ROSC, and is more often associated with rhythm deterioration.     

Comparing the survival between extracorporeal rescue and conventional resuscitation in adult in-hospital cardiac arrests: Propensity analysis of three-year data

Aim

Extracorporeal cardiopulmonary resuscitation (ECPR) has been shown to have survival benefit over conventional CPR (CCPR) in patients with in-hospital cardiac arrest of cardiac origin. We compared the survival of patients who had return of spontaneous beating (ROSB) after ECPR with the survival of those who had return of spontaneous circulation (ROSC) after conventional CPR.

Methods

Propensity score-matched cohort of adults with in-hospital prolonged CPR (>10 min) of cardiac origin in a university-affiliated tertiary extracorporeal resuscitation center were included in this study. Fifty-nine patients with ROSB after ECPR and 63 patients with sustained ROSC by CCPR were analyzed. Main outcome measures were survival at hospital discharge, 30 days, 6 months, and one year, and neurological outcome.

Results

There was no statistical difference in survival to discharge (29.1% of ECPR responders vs. 22.2% of CCPR responders, p = 0.394) and neurological outcome at discharge and one year later. In the propensity score-matched groups, 9 out of 27 ECPR patients survived to one month (33.3%) and 7 out of 27 CCPR patients survived (25.9%). Survival analysis showed no survival difference (HR: 0.856, p = 0.634, 95% CI: 0.453-1.620) between the groups, either at 30 days or at the end of one year (HR: 0.602, p = 0.093, 95% CI: 0.333-1.088).

Conclusions

This study failed to demonstrate a survival difference between patients who had ROSB after institution of ECMO and those who had ROSC after conventional CPR. Further studies evaluating the role of ECMO in conventional CPR rescued patients are warranted.     

Incidence and outcomes of out-of-hospital cardiac arrest with shock-resistant ventricular fibrillation: Data from a large population-based cohort

Background

The increasing survival rates after out-of-hospital cardiac arrests (OHCA) are due mainly to improvements in the first 3 steps of the chain of survival. The aim of this study was to describe the temporal trends of OHCA incidence and outcomes with shock-resistant ventricular fibrillation (VF) requiring advanced life support procedures.

Methods

All our subjects were persons aged 18 years or more who had suffered OHCA of presumed cardiac etiology, were witnessed by bystanders, treated by emergency medical service (EMS), and had VF as initial rhythm. Our study was conducted in Osaka Prefecture, Japan from May 1, 1998 through December 31, 2006. Data were collected by EMS personnel using an Utstein-style database. We evaluated the temporal trends of incidence and outcomes of shock-resistant VF.

Results

During the study period, there were 8782 witnessed OHCA cases of presumed cardiac etiology. Among them, 1733 had VF as an initial rhythm, 392 of whom were shock-resistant. While the age-adjusted annual incidence of witnessed VF increased from 2.0 to 3.3 per 100,000 inhabitants, that of shock-resistant VF underwent little change during the study period. The proportion of shock-resistant VF among witnessed VF decreased from 37.0% to 19.0%. Neurologically intact 1-month survival rates after shock-resistant VF remained low at 5.6% even in 2006.

Conclusion

The actual incidence of shock-resistant VF has remained unchanged, and their outcomes continue to be dismal. Further efforts are required to reduce the mortality rates of such shock-resistant VF to achieve improved survival after OHCA.     

Continuous mechanical chest compression during in-hospital cardiopulmonary resuscitation of patients with pulseless electrical activity

Survival after in-hospital pulseless electrical activity (PEA) cardiac arrest is poor and has not changed during the last 10 years. Effective chest compressions may improve survival after PEA. We investigated whether a mechanical device (LUCAS™-CPR) can ensure chest compressions during cardiac arrest according to guidelines and without interruption during transport, diagnostic procedures and in the catheter laboratory.

Methods

We studied mechanical chest compression in 28 patients with PEA (pulmonary embolism (PE) n = 14; cardiogenic shock/acute myocardial infarction; n = 9; severe hyperkalemia; n = 2; sustained ventricular arrhythmias/electrical storm; n = 3) in a university hospital setting.

Results

During or immediately after CPR, 21 patients underwent coronary angiography and or pulmonary angiography. Successful return of a spontaneous circulation (ROSC) was achieved in 27 out of the 28 patients. Ten patients died within the first hour and three patients died within 24 h after CPR. A total of 14 patients survived and were discharged from hospital (13 without significant neurological deficit). Interestingly, six patients with PE did not have thrombolytic therapy due to contraindications. CT-angiography findings in these patients showed fragmentation of the thrombus suggesting thrombus breakdown as an additional effect of mechanical chest compressions. No patients exhibited any life-threatening device-related complications.

Conclusion

Continuous chest compression with an automatic mechanical device is feasible, safe, and might improve outcomes after in-hospital-resuscitation of PEA. Patients with PE may benefit from effective continuous chest compression, probably due to thrombus fragmentation and increased pulmonary artery blood flow.     

Hypocalcemia following resuscitation from cardiac arrest revisited

Objective

Hypocalcemia associated with cardiac arrest has been reported. However, mechanistic hypotheses for the decrease in ionized calcium (iCa) vary and its importance unknown. The objective of this study was to assess the relationships of iCa, pH, base excess (BE), and lactate in two porcine cardiac arrest models, and to determine the effect of exogenous calcium administration on post-resuscitation hemodynamics.

Methods

Swine were instrumented and VF was induced either electrically (EVF, n = 65) or spontaneously, ischemically induced (IVF) with balloon occlusion of the LAD (n = 37). Animals were resuscitated after 7 min of VF. BE, iCa, and pH, were determined prearrest and at 15, 30, 60, 90, 120 min after ROSC. Lactate was also measured in 26 animals in the EVF group. Twelve EVF animals were randomized to receive 1 g of CaCl₂ infused over 20 min after ROSC or normal saline.

Results

iCa, BE, and pH declined significantly over the 60 min following ROSC, regardless of VF type, with the lowest levels observed at the nadir of left ventricular stroke work post-resuscitation. Lactate was strongly correlated with BE (r = −0.89, p < 0.0001) and iCa (r = −0.40, p < 0.0001). In a multivariate generalized linear mixed model, iCa was 0.005 mg/dL higher for every one unit increase in BE (95% CI 0.003-0.007, p < 0.0001), while controlling for type of induced VF. While there was a univariate correlation between iCa and BE, when BE was included in the regression analysis with lactate, only lactate showed a statistically significant relationship with iCa (p = 0.02). Post-resuscitation CaCl₂ infusion improved post-ROSC hemodynamics when compared to saline infusion (LV stroke work control 8 ± 5 g m vs 23 ± 4, p = 0.014, at 30 min) with no significant difference in tau between groups.

Conclusions

Ionized hypocalcemia occurs following ROSC. CaCl₂ improves post-ROSC hemodynamics suggesting that hypocalcemia may play a role in early post-resuscitation myocardial dysfunction.     

Post-resuscitative clinical features in the first hour after achieving sustained ROSC predict the duration of survival in children with non-traumatic out-of-hospital cardiac arrest

Aim of the study

Although sustained return of spontaneous circulation (ROSC) can be initially established after resuscitation from non-traumatic out-of-hospital cardiac arrest (OHCA) in some children, many of the children lose spontaneous circulation during hospital stay and do not survive to discharge. The aim of this study was to determine the clinical features during the first hour after ROSC that may predict survival to hospital discharge.

Methods

We retrospectively evaluated the medical records of 228 children who presented to the emergency department without spontaneous circulation following non-traumatic OHCA during the period January 1996 to December 2008. Among these children, 80 achieved sustained ROSC for at least 20 min. The post-resuscitative clinical features during the first hour after achieving sustained ROSC that correlated with survival, median duration of survival, and death were analyzed.

Results

Among the 80 children who achieved sustained ROSC for at least 20 min, 28 survived to hospital discharge and 6 had good neurologic outcomes (PCPC scale = 1 or 2). Post-resuscitative clinical features associated with survival included sinus cardiac rhythm (p = 0.012), normal heart rate (p = 0.008), normal blood pressure (p < 0.001), urine output > 1 ml/kg/h (p = 0.002), normal skin color (p = 0.016), lack of cardiopulmonary resuscitation (CPR)-induced rib fracture (p = 0.044), initial Glasgow Coma Scale score > 7 (p < 0.001), and duration of in-hospital CPR ≤ 10 min (p < 0.001). Furthermore, these variables were also significantly associated with the duration of survival (all p < 0.05).

Conclusions

The most important predictors of survival to hospital discharge in children with OHCA who achieve sustained ROSC are a normal heart rate, normal blood pressure, and an initial urine output > 1 ml/kg/h.     

Early coronary revascularization improves 24 h survival and neurological function after ischemic cardiac arrest. A randomized animal study

Background

Survival after out-of-hospital cardiac arrest (OHCA) remains poor. Acute coronary obstruction is a major cause of OHCA. We hypothesize that early coronary reperfusion will improve 24 h-survival and neurological outcomes.

Methods

Total occlusion of the mid LAD was induced by balloon inflation in 27 pigs. After 5 min, VF was induced and left untreated for 8 min. If return of spontaneous circulation (ROSC) was achieved within 15 min (21/27 animals) of cardiopulmonary resuscitation (CPR), animals were randomized to a total of either 45 min (group A) or 4 h (group B) of LAD occlusion. Animals without ROSC after 15 min of CPR were classified as refractory VF (group C). In those pigs, CPR was continued up to 45 min of total LAD occlusion at which point reperfusion was achieved. CPR was continued until ROSC or another 10 min of CPR had been performed. Primary endpoints for groups A and B were 24-h survival and cerebral performance category (CPC). Primary endpoint for group C was ROSC before or after reperfusion.

Results

Early compared to late reperfusion improved survival (10/11 versus 4/10, p = 0.02), mean CPC (1.4 ± 0.7 versus 2.5 ± 0.6, p = 0.017), LVEF (43 ± 13 versus 32 ± 9%, p = 0.01), troponin I (37 ± 28 versus 99 ± 12, p = 0.005) and CK-MB (11 ± 4 versus 20.1 ± 5, p = 0.031) at 24-h after ROSC. ROSC was achieved in 4/6 animals only after reperfusion in group C.

Conclusions

Early reperfusion after ischemic cardiac arrest improved 24 h survival rate and neurological function. In animals with refractory VF, reperfusion was necessary to achieve ROSC.