A 5-year experience with cardiopulmonary resuscitation using extracorporeal life support in non-postcardiotomy patients with cardiac arrest

Background

Cardiopulmonary resuscitation (CPR) using extracorporeal life support (ECLS) system has been successfully used to support patients with in- and out-of-hospital cardiac arrest (IHCA, OHCA) when conventional measures have failed. The purpose of the current study is to report on our experience with extracorporeal CPR in non-postcardiotomy patients.

Methods

We retrospectively analysed a total of 85 consecutive adult patients, who have been treated with ECLS between January 2007 and January 2012.

Results

The mean CPR duration was 40 min (20–70 min). The mean ECLS support duration was 49 h (12–92 h). Twenty-eight patients (33%) had ECLS related complications. Forty patients (47%) were successfully weaned and 29 patients (34%) survived to hospital discharge. Among survivors, 93% were without severe neurologic deficit. Duration of CPR was shorter for survivors than for non-survivors [(25: 20–50 min) vs. (50: 25–86 min); p = 0.003]. Immediately after ECLS start, the mean blood lactate level was lower (p = 0.003), and the mean pH value was higher in the survivors’ group (p < 0.0001) compared to the non-survivors’ group. The CPR duration for the IHCA group (25: 20–50 min) was shorter compared to the OHCA group (70: 55–110 min; p < 0.0001). The survival rate in this group was higher compared to the OHCA group (42% vs. 15%; p < 0.02).

Conclusions

CPR using modern miniaturized ECLS systems should be established in the treatment of prolonged cardiac arrest and unsuccessful conventional CPR in selected patients. CPR with ECLS for OHCA has worse outcomes compared to IHCA. Duration of CPR was independent risk factor for mortality after extracorporeal CPR.     

Improved outcome of extracorporeal cardiopulmonary resuscitation for out-of-hospital cardiac arrest – A comparison with that for extracorporeal rescue for in-hospital cardiac arrest

Purpose

The aim was to investigate the effects of extracorporeal cardiopulmonary resuscitation (ECPR) for out-of-hospital cardiac arrest (OHCA) and compare the results with those of in-hospital cardiac arrest (IHCA).

Methods

We analyzed our extracorporeal membrane oxygenation (ECMO) results for patients who received ECPR for OHCA or IHCA in the last 5 years. Pre-arrest, resuscitation, and post-resuscitative data were evaluated.

Results

In the last 5 years, ECPR was used 230 times for OHCA (n = 31) and IHCA (n = 199). The basic demographic data showed significant differences in age, cardiomyopathy, and location of the initial CPR. Duration of ischemia was shorter in the IHCA group (44.4 ± 24.7 min vs. 67.5 ± 30.6 min, p < 0.05). About 50% of each group underwent a further intervention to treat the underlying etiology. ECMO was maintained for a shorter duration in the OHCA patients (61 ± 48 h vs. 94 ± 122 h, p < 0.05). Survival to discharge was similar in the two groups (38.7% for OHCA vs. 31.2% for IHCA, p > 0.05), as was the favorable outcome rate (25.5% for OHCA vs. 25.1% for IHCA, p > 0.05). Survival was acceptable (about 33%) in both groups when the duration of ischemia was no longer than 75 min.

Conclusions

In addition to having a beneficial effect in IHCA, ECPR can lead to survival and a positive neurological outcome in selected OHCA patients after prolonged resuscitation. Our results suggest that further investigation of the use of ECMO in OHCA is warranted.     

Usefulness of routine laboratory parameters in the decision to treat refractory cardiac arrest with extracorporeal life support

Aim

To evaluate the usefulness of routine laboratory parameters in the decision to treat refractory cardiac arrest patients with extracorporeal life support (ECLS).

Methods

Sixty-six adults with witnessed cardiac arrest of cardiac origin unrelated to poisoning or hypothermia undergoing cardiopulmonary resuscitation without return of spontaneous circulation (duration: 155 min [120-180], median, [25-75%-percentiles]) were included in a prospective cohort-study. ECLS was implemented under cardiac massage, using a centrifugal pump connected to a hollow-fiber membrane-oxygenator, aiming to maintain ECLS flow ≥2.5 l/min and mean arterial pressure ≥60 mm Hg.

Results

Forty-seven of 66 patients died within 24 h from multiorgan failure and massive capillary leak. Of 19/66 patients who survived ≥24 h with stable circulatory conditions permitting neurological evaluation, four became conscious and were transferred for further cardiac assistance, while three became organ donors. Ultimately, one patient survived without neurologic sequelae after cardiac transplantation. Using multivariate analysis, only pre-cannulation peripheral venous oxygen saturation (SpvO₂, 28% [15-52]) independently predicted inability to maintain targeted ECLS conditions ≥24 h (odds ratio for each 10%-decrease [95%-confidence interval]: 1.65 [1.21; 2.25], p = 0.002). The area under the receiver-operating-characteristics curve was 0.78 [0.63; 0.93]. SpvO₂ cut-off value of 33% was associated with a sensitivity of 0.68 [0.50; 0.83] and specificity of 0.81 [0.54; 0.96]. SpvO₂ ≤8%, lactate concentration ≥21 mmol/l, fibrinogen ≤0.8 g/l, and prothrombin index ≤11% predicted premature ECLS discontinuation with a specificity of 1.

Conclusion

SpvO₂ is useful to predict the inability of maintaining refractory cardiac arrest victims on ECLS without detrimental capillary leak and multiorgan failure until neurological evaluation.     

Are trained individuals more likely to perform bystander CPR? An observational study

Background

This study aimed to evaluate the association of cardiopulmonary resuscitation (CPR) training with bystander resuscitation performance and patient outcomes after out-of-hospital cardiac arrest (OHCA).

Methods

This was a prospective, population-based cohort study of all persons aged 18 years or older with OHCA of presumed intrinsic origin and their rescuers from January through December 2008 in Takatsuki, Osaka prefecture, Japan. Data on resuscitation of OHCA patients were obtained by emergency medical service (EMS) personnel in charge based on the Utstein style. Rescuers’ characteristics including experience of CPR training were obtained by EMS personnel interview on the scene. The primary outcome was the attempt of bystander CPR.

Results

Data were collected for 120 cases out of 170 OHCAs of intrinsic origin. Among the available cases, 60 (50.0%) had previous CPR training (trained rescuer group). The proportion of bystander CPR was significantly higher in the trained rescuer group than in the untrained rescuer group (75.0% and 43.3%; p = 0.001). Bystanders who had previous experience of CPR training were 3.40 times (95% confidence interval 1.31-8.85) more likely to perform CPR compared with those without previous CPR training. The number of patients with neurologically favorable one-month survival was too small to evaluate statistical difference between the groups (2 [3.3%] in the trained rescuer group versus 1 [1.7%] in the untrained rescuer group; p = 0.500).

Conclusions

People who had experienced CPR training had a greater tendency to perform bystander CPR than people without experience of CPR training. Further studies are needed to prove the effectiveness of CPR training on survival.     

Effect of time and day of admission on 1-month survival and neurologically favourable 1-month survival in out-of-hospital cardiopulmonary arrest patients

Aim

We sought to examine whether the outcomes of out-of-hospital cardiopulmonary arrest (OHCA) patients differed between weekday and weekend/holiday admissions, or between daytime and nighttime admissions.

Methods

From a national registry of OHCA events in Japan between 2005 and 2008, 173,137 cases where the call-to-hospital admission interval was shorter than 120 min and collapse was witnessed by a bystander were included in this study. One-month survival rate and neurologically favourable 1-month survival rate were used as outcome measures. Logistic regression was used to adjust for potential confounding factors.

Results

No significant differences in outcome were found between weekday and holiday/weekend admissions in rates of 1-month survival or neurologically favourable 1-month survival (p = 0.78 and p = 0.80, respectively). In contrast, patients admitted in the daytime exhibited significantly better outcomes than those admitted at night, on both outcome measures (p < 0.001 and p < 0.001). After adjusting for possible confounding factors, outcomes were significantly better for daytime admissions, with odds ratios of 1.26 (95% confidence interval (CI) 1.22-1.31; p < 0.001) for 1-month survival, and 1.26 (95% CI 1.20-1.32; p < 0.001) for neurologically favourable 1-month survival. In contrast, no significant differences on either outcome measure were found between weekday and weekend/holiday cases, with odds ratios of 1.00 (95% CI 0.96-1.04; p = 0.96) for 1-month survival and 0.99 (95% CI 0.94-1.04; p = 0.78) for neurologically favourable 1-month survival.

Conclusions

Even after adjusting for confounding factors, admission day (weekday vs. weekend/holiday) had no effect on 1-month survival or neurologically favourable 1-month survival. In contrast, daytime admission was associated with significantly better outcomes than nighttime admissions.     

Improving outcome after out-of-hospital cardiac arrest by strengthening weak links of the local Chain of Survival; quality of advanced life support and post-resuscitation care

Background

Survival after out-of-hospital cardiac arrest (OHCA) depends on a well functioning Chain of Survival. We wanted to assess if targeted attempts to strengthen the weak links of our local chain; quality of advanced life support (ALS) and post-resuscitation care, would improve outcome.

Materials and methods

Utstein data from all OHCAs in Oslo during three distinct 2-year time periods 1996-1998, 2001-2003 and 2004-2005 were collected. Before the second period the local ALS guidelines changed with increased focus on good quality chest compressions with minimal pauses, while standardized post-resuscitation care including goal directed therapy with therapeutic hypothermia and percutaneous coronary intervention was added in the third period. Additional a priori sub-group analyses of arrests with cardiac aetiology as well as bystander witnessed ventricular fibrillation/tachycardia (VF/VT) arrests with cardiac aetiology were performed.

Results

ALS was attempted in 454, 449, and 417 patients with OHCA in the first, second and last time period, respectively. From the first to the third period VF/VT arrests declined (40% vs. 33%, p = 0.039) and fewer arrests were witnessed (80% vs. 72%, p = 0.022) and response intervals increased (7 ± 4 to 9 ± 4 min, p < 0.001). Overall survival increased from 7% (first period) to 13% (last period), p = 0.002, and survival in the sub-group of bystander witnessed VF/VT arrests with cardiac aetiology increased from 15% (first period) to 35% (last period), p = 0.001.

Conclusions

Survival after OHCA was increased after improving weak links of our local Chain of Survival, quality of ALS and post-resuscitation care.     

Hypokalemia during the cooling phase of therapeutic hypothermia and its impact on arrhythmogenesis

Background

Mild to moderate therapeutic hypothermia (TH) has been shown to improve survival and neurological outcome in patients resuscitated from out-of-hospital cardiac arrest (OHCA) with ventricular fibrillation (VF) as the presenting rhythm. This approach entails the management of physiological variables which fall outside the realm of conventional critical cardiac care. Management of serum potassium fluxes remains pivotal in the avoidance of lethal ventricular arrhythmia.

Methods

We retrospectively analyzed potassium variability with TH and performed correlative analysis of QT intervals and the incidence of ventricular arrhythmia.

Results

We enrolled 94 sequential patients with OHCA, and serum potassium was followed intensively. The average initial potassium value was 3.9 ± 0.7 mmol l⁻¹ and decreased to a nadir of 3.2 ± 0.7 mmol l⁻¹ at 10 h after initiation of cooling (p < 0.001). Eleven patients developed sustained polymorphic ventricular tachycardia (PVT) with eight of these occurring during the cooling phase. The corrected QT interval prolonged in relation to the development of hypothermia (p < 0.001). Hypokalemia was significantly associated with the development of PVT (p = 0.002), with this arrhythmia being most likely to develop in patients with serum potassium values of less than 2.5 mmol l⁻¹ (p = 0.002). Rebound hyperkalemia did not reach concerning levels (maximum 4.26 ± 0.8 mmol l⁻¹ at 40 h) and was not associated with the occurrence of ventricular arrhythmia. Furthermore, repletion of serum potassium did not correlate with the development of ventricular arrhythmia.

Conclusions

Therapeutic hypothermia is associated with a significant decline in serum potassium during cooling. Hypothermic core temperatures do not appear to protect against ventricular arrhythmia in the context of severe hypokalemia and cautious supplementation to maintain potassium at 3.0 mmol l⁻¹ appears to be both safe and effective.     

Esophageal temperature after out-of-hospital cardiac arrest: An observational study

Introduction

Out-of-hospital cardiac arrest (OHCA) is a significant cause of death and severe neurological disability. The only post-return of spontaneous circulation (ROSC) therapy shown to increase survival is mild therapeutic hypothermia (MTH). The relationship between esophageal temperature post OHCA and outcome is still poorly defined.

Methods

Prospective observational study of all OHCA patients admitted to a single centre for a 14-month period (1/08/2008 to 31/09/2009). Esophageal temperature was measured in the Emergency Department and Intensive Care Unit (ICU). Selected patients had pre-hospital temperature monitoring. Time taken to reach target temperature after ROSC was recorded, together with time to admission to the Emergency Department and ICU.

Results

164 OHCA patients were included in the study. 105 (64.0%) were pronounced dead in the Emergency Department. 59 (36.0%) were admitted to ICU for cooling; 40 (24.4%) died in ICU and 19 (11.6%) survived to hospital discharge. Patients who achieved ROSC and had esophageal temperature measured pre-hospital (n = 29) had a mean pre-hospital temperature of 33.9 °C (95% CI 33.2-34.5). All patients arriving in the ED post OHCA had a relatively low esophageal temperature (34.3 °C, 95% CI 34.1-34.6). Patients surviving to hospital discharge were warmer on admission to ICU than patients who died in hospital (35.7 °C vs 34.3 °C, p < 0.05). Patients surviving to hospital discharge also took longer to reach T_targ than non-survivors (2 h 48 min vs 1 h 32 min, p < 0.05).

Conclusions

Following OHCA all patients have esophageal temperatures below normal in the pre-hospital phase and on arrival in the Emergency Department. Patients who achieve ROSC following OHCA and survive to hospital discharge are warmer on arrival in ICU and take longer to reach target MTH temperatures compared to patients who die in hospital. The mechanisms of action underlying esophageal temperature and survival from OHCA remain unclear and further research is warranted to clarify this relationship.     

Extra corporeal life support makes advanced radiologic examinations and cardiac interventions possible in patients with cardiac arrest

Objectives

Extra corporeal life support (ECLS) with a mobile system is an option in the treatment of cardiac arrest often of unknown reason. After commencing ECLS the search for a provoking origin may include advanced radiologic examinations before deciding further treatment.

Methods

Fifty-eight patients with circulatory arrest were treated with ECLS. In 15 cases the patient went through CT scans of the cerebrum, thorax and abdomen, pulmonary angiography, and or invasive cardiologic examinations. Two patients were transported in ambulance and helicopter on ECLS before the examinations.

Results

The underlying diagnosis in the 15 patients were: lung embolism (n = 6), accidental hypothermia (n = 2), myocardial infarction (n = 2), WPW syndrome (n = 1), sepsis (n = 1), disseminated intravascular coagulation (n = 2), high voltage accident (n = 1). Only in the last mentioned patient the CT scan was indicative of major brain damage, and further treatment was stopped. Five of the 15 examined patients survived. The diagnoses in the survivors were lung embolism (n = 2), myocardial infarction (n = 1), WPW syndrome (n = 1), and accidental hypothermia (n = 1). The results of the radiologic examinations had great influence on all treatments.

Conclusions

It is possible to make radiological examinations i.e., CT scans, pulmonary and coronary angiography in patients suffering heart arrest of unknown origin with the use of ECLS in order to improve patient treatment in this very high-risk population.     

Impact of transport to critical care medical centers on outcomes after out-of-hospital cardiac arrest

Background

Post-resuscitation care has emerged as an important predictor of survival from out-of-hospital cardiac arrest (OHCA). In Japan, selected hospitals are certified as Critical Care Medical Centers (CCMCs) based on their ability and expertise.

Hypothesis

Outcome after OHCA is better in patients transported to a CCMC compared a non-critical care hospital (NCCH).

Materials and methods

Adults with OHCA of presumed cardiac etiology, treated by emergency medical services systems, and transported in Osaka from January 1, 2005 to December 31, 2007 were registered using a prospective Utstein style population cohort database. Primary outcome measure was 1 month neurologically favorable survival (CPC ≤ 2). Outcomes of patients transported to CCMC were compared with patients transported to NCCH using multiple logistic regressions and stratified on the basis of stratified field ROSC.

Results

10,383 cases were transported. Of these, 2881 were transported to CCMC and 7502 to NCCH. Neurologically favorable 1-month survival was greater in the CCMC group [6.7% versus 2.8%, P < 0.001]. Among patients who were transported to hospital without field ROSC, neurologically favorable outcome was greater in the CCMC group than the NCCH group [1.7% versus 0.5%; adjusted odds ratio (OR), 3.39; 95% confidence interval (CI), 2.17-5.29; P < 0.001]. In the presence of field ROSC, survival was similar between the groups [43% versus 41%; adjusted OR, 1.09; 95% CI, 0.82-1.45; P = 0.554].

Conclusions

Survival after OHCA of presumed cardiac etiology transported to CCMCs was better than those transported to NCCHs. For OHCA patients without field ROSC, transport to a CCMC was an independent predictor for a good neurological outcome.     

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.     

Cardiac arrest outcomes before and after the 2005 resuscitation guidelines implementation: evidence of improvement?

Background

Previous studies have reported improvements in out-of-hospital cardiac arrest (OHCA) outcomes with the introduction of the 2005 cardiopulmonary resuscitation guidelines however they have not adjusted for underlying trends in OHCA survival. We compare outcomes before and after the 2005 guideline changes adjusting for underlying trends in OHCA survival.

Methods

The Victorian Ambulance Cardiac Arrest Registry (VACAR) was searched for adult (≥16 years) OHCA of presumed cardiac aetiology, unwitnessed by paramedics with attempted resuscitation. Outcomes for OHCA occurring between 2003 and 2005 were compared with 2007-2009. Segmented regression analysis of interrupted time series data was performed, adjusting for known predictors, to examine changes in survival to hospital and survival to hospital discharge.

Results

For the pre- and post- guideline periods there were 3115 and 3248 OHCAs, respectively. Asystole increased as presenting rhythm (33-43%, p < 0.001) as did median EMS response times (7.1-7.8 min, p < 0.001) over the two periods. VF/VT arrests decreased (40-35.5%, p = 0.001) as did bystander witnessed arrests (63-59%, p = 0.002). On univariate analysis survival to hospital discharge improved between the two periods (9.4-11.8%, p = 0.002) due to improved outcomes in VF/VT (19-28%, p < 0.001). Segmented regression analysis of interrupted time series data showed improvement in the rate of survival to get to hospital for shockable and non-shockable rhythms [OR (95% CI) = 1.54 (1.10-2.15, p = 0.01) and 1.45 (1.10-2.00, p = 0.02), respectively] following implementation of the guidelines however survival to hospital discharge did not improve [OR = 1.07 (0.70-1.62, p = 0.70) and 1.40 (0.69-2.85, p = 0.40), respectively].

Conclusions

OHCA outcomes have improved since introduction of the 2005 CPR guidelines, but multivariable segmented regression analysis adjusting for pre-existing trends in survival suggests that this improvement may not be due to implementation of the 2005 resuscitation guidelines.     

Pulmonary embolectomy in high-risk acute pulmonary embolism: The effectiveness of a comprehensive therapeutic algorithm including extracorporeal life support

Objectives

To investigate the effectiveness of a comprehensive therapeutic algorithm including extracorporeal life support (ECLS) in high-risk acute pulmonary embolism (aPE) treated with pulmonary embolectomy.

Materials and methods

This retrospective study included 25 consecutive patients of aPE treated with pulmonary embolectomy in a single institution between June 2005 and July 2012. All patients had high-risk aPE identified by computed tomographic angiography and were not suitable for thrombolytic therapy. High-risk aPE here was defined as aPE with (1) hemodynamic instability, (2) a pulmonary artery obstruction index (PAOI) ≥ 0.5, (3) a diameter ratio of right ventricle-to-left ventricle (RV-to-LV) ≥ 1.0, or (4) right heart thrombi. Once the eligibility was confirmed, a 3-staged therapeutic algorithm was adopted to perform an aggressive preoperative resuscitation, an expeditious pulmonary embolectomy with multidisciplinary postoperative care, and a thorough surveillance for recurrence.

Results

Among the 25 patients, 24 had a PAOI ≥ 0.5 and 23 had a RV-to-LV diameter ratio ≥ 1.0. Four patients had right heart thrombi. Sixteen patients developed preoperative instability requiring inotropic and/or mechanical support. Eight in the 16 had a preoperative cardiac arrest (CA) and six of these were bridged to surgery on ECLS. Three in the 6 patients weaned ECLS after surgery and survived to discharge. The overall in-hospital mortality was 20% (n = 5). A preoperative CA (Odds ratio [OR]: 16, 95% confidence interval [CI]: 1.4–185.4, p = 0.027, c-index: 0.80) and a postoperative requirement of ECLS (OR: 36, 95% CI: 2.1–501.3, p = 0.008, c-index: 0.85) was the pre- and postoperative predictor of in-hospital mortality. No late deaths or re-admission for recurrence were found during a median follow-up of 19 months (interquartile range: 8–29).

Conclusion

Pulmonary embolectomy was an effective intervention of high-risk aPE. However, the occurrence of preoperative CA still carried a high mortality in spite of the assistance of ECLS.     

Good outcome in every fourth resuscitation attempt is achievable--an Utstein template report from the Stavanger region

Aim of the study

Out-of-hospital cardiac arrest (OHCA) is a major cause of death in the western world. We wanted to study changes in survival over time and factors linked to this in a region which have already reported high survival rates.

Methods

We used a prospectively collected Utstein template database to identify all resuscitation attempts in adult patients with OHCA of presumed cardiac origin. We included 846 resuscitation attempts and compared survival to discharge with good outcome in two time periods (2001-2005 vs. 2006-2008).

Results

We found no significant differences between the two time periods for mean age (71 and 70 years (p = 0.309)), sex distribution (males 70% and 71% (p = 0.708)), location of the OHCA (home 64% and 63% (p = 0.732)), proportion of shockable rhythms (44% and 47% (p = 0.261)) and rate of return of spontaneous circulation (38% and 43% (p = 0.136)), respectively. Bystander cardiopulmonary resuscitation (CPR), however, increased significantly from 60% to 73% (p < 0.0001), as did the overall rate of survival to discharge from 18% to 25% (p = 0.018). In patients with a shockable first rhythm, rate of survival to discharge increased significantly from 37% to 48% (p = 0.036). In witnessed arrest with shockable rhythm survival to discharge increased from 37% to 52% (p = 0.0105).

Conclusion

Overall, good outcome is now achievable in every fourth resuscitation attempt and in every second resuscitation attempt when patients have a shockable rhythm. The reason for the better outcomes is most likely multi-factorial and linked to improvements in the local chain of survival.     

Mild hypothermia reduces acute mortality and improves hemodynamic outcome in a cardiogenic shock pig model

Introduction

Cardiogenic shock is the main cause of death in patients hospitalized due to an acute myocardial infarction. Mild hypothermia reduces metabolism and could offer protective effects for this condition. The aim of our study was to investigate if mild therapeutic hypothermia would improve outcome and hemodynamic parameters in an ischemic cardiogenic shock pig model.

Methods

Twenty-five pigs (40-50 kg) were anesthetized and a normothermic temperature of 38 °C was established utilising an endovascular cooling catheter in a closed-chest model. A Swan-Ganz catheter was placed in the pulmonary artery. Hemodynamic parameters were continuously monitored and blood gases were sampled every 30 min. Ischemia was induced by inflation of a PCI balloon in proximal LAD for 40 min. Sixteen pigs that have fulfilled predefined shock criteria were randomized to hypothermia (n = 8), or normothermia (n = 8). Hypothermia (33 °C) was induced after onset of reperfusion by using an endovascular temperature modulating catheter and was maintained until termination of the experiment.

Results

The pigs in the hypothermia group were cooled to <34 °C in approximately 45 min. 5/8 pigs in the normothermia group died while all pigs in the hypothermia group survived (p < 0.01). Stroke volume and blood pressure were significantly higher in the hypothermia group (p < 0.05), whereas heart rate was significantly lower in the hypothermia group (p = 0.01). Cardiac output did not differ among the groups (p = 0.13). Blood gas analysis revealed higher mixed venous oxygen saturation, pH, and base excess in the hypothermia group indicating less development of metabolic acidosis (p < 0.05).

Conclusions

In this pig model, mild therapeutic hypothermia reduces acute mortality in cardiogenic shock, improves hemodynamic parameters and reduces metabolic acidosis. These findings suggest a possible clinical benefit of therapeutic hypothermia for patients with acute cardiogenic shock.     

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.     

Out-of-hospital cardiac arrests in young adults in Melbourne, Australia

Background

Characteristics and outcomes of out-of-hospital cardiac arrest (OHCA) in young adults are not well described in Australia.

Methods

A 10-year retrospective case review of all OHCA in young adults (aged 16-39) and not witnessed by EMS, was performed using data from the Victorian Ambulance Cardiac Arrest Registry (VACAR).

Results

Between 2000 and 2009 there were 30,006 adult cardiac arrests of which 3912 (13%) were in this age group. The median (IQR) age was 30 (25-35) years for both sexes with a 3:1 male to female ratio. Overdose was the most common precipitant (33.5%) followed by presumed cardiac (20%). Bystander CPR occurred in 21.2%, EMS median response time was 7 min and resuscitation was attempted in 36% of OHCAs. The presenting rhythm was asystole in 84.6%, PEA in 8.8% and VF/VT in 6.6%. Survival to hospital discharge, for all cause OHCA where resuscitation was attempted, was similar for young adult and older adults (8.8% vs 8.4%, p = 0.2). However, for presumed cardiac aetiology OHCA, young adults had a greater proportion of survivors (14.8% vs 9.0%, p < 0.001). Cardiac arrest with shockable rhythm (VF/pulseless VT) had a survival rate of 31.2% for young adults compared to 18.5% for older adults (p < 0.001).

Conclusion

Survival to hospital discharge rates from OHCA due to a ‘presumed cardiac’ precipitant in young adults is much better than older adults, however, all cause OHCA survival is similar. Multi agency novel upstream preventive strategies aimed at tackling drug overdose may reduce this aetiology of OHCA and save lives.     

Pulse pressure as a prognostic marker in patients receiving extracorporeal life support

Background

It is not easy to predict the prognosis of patients receiving extracorporeal life support (ECLS) because of the highly variable situation around its implementation. We evaluated the role of pulse pressure (PP), which is available on real-time basis, as a hemodynamic prognostic marker during ECLS.

Methods

From January 2009 to August 2011, data from 69 patients who were treated with ECLS for at least 6 h in a single center for any cause was collected. We calculated the mean PP over the first 6 h after ECLS implantation and examined if there was any correlation between mean PP and the study endpoints, in-hospital death and ECLS weaning failure.

Results

The causes of ECLS were of cardiac origin in 36 patients (52%). 27 patients (39.1%) weaned off ELCS and 13 patients (18.8%) survived to discharge. In Cox regression analysis (with age, Killip class ≥3, ECLS implementation during cardiopulmonary resuscitation (CPR), CPR duration, out-of-hospital arrest, initial laboratory results including blood gas analysis, initial systolic blood pressure (SBP), mean SBP over the first 6 h after ECLS implantation, mean PP over the first 6 h after ECLS implantation as independent variables), mean PP over the first 6 h after ECLS implantation (hazard ratio [95% confidence interval] = 0.96[0.94–0.98], P < 0.001) and out-of-hospital arrest (HR[95%CI] = 2.04[1.14–3.62], P = 0.02) were independent predictors of in-hospital mortality and mean PP over the first 6 h after ECLS implantation (HR[95% CI] = 0.95[0.93–0.98], P < 0.001) was the sole independent predictor of weaning failure.

Conclusion

Higher mean PP over the initial 6 h after ECLS implementation independently predicted successful weaning and survival. Our findings may help better predict and analyze prognosis in patients receiving ECLS.     

Out-of-hospital cardiac arrest frequency and survival: Evidence for temporal variability

Aim

Some cardiac phenomena demonstrate temporal variability. We evaluated temporal variability in out-of-hospital cardiac arrest (OHCA) frequency and outcome.

Methods

Prospective cohort study (the Resuscitation Outcomes Consortium) of all OHCA of presumed cardiac cause who were treated by emergency medical services within 9 US and Canadian sites between 12/1/2005 and 02/28/2007. In each site, Emergency Medical System records were collected and analyzed. Outcomes were individually verified by trained data abstractors.

Results

There were 9667 included patients. Median age was 68 (IQR 24) years, 66.7% were male and 8.3% survived to hospital discharge. The frequency of cardiac arrest varied significantly across time blocks (p < 0.001). Compared to the 0001-0600 hourly time block, the odds ratios and 95% CIs for the occurrence of OHCA were 2.02 (1.90, 2.15) in the 0601-1200 block, 2.01 (1.89, 2.15) in the 1201-1800 block, and 1.73 (1.62, 1.85) in the 1801-2400 block. The frequency of all OHCA varied significantly by day of week (p = 0.03) and month of year (p < 0.001) with the highest frequencies on Saturday and during December. Survival to hospital discharge was lowest when the OHCA occurred during the 0001-0600 time block (7.3%) and highest during the 1201-1800 time block (9.6%). Survival was highest for OHCAs occurring on Mondays (10.0%) and lowest for those on Wednesdays (6.8%) (p = 0.02).

Conclusion

There is temporal variability in OHCA frequency and outcome. Underlying patient, EMS system and environmental factors need to be explored to offer further insight into these observed patterns.     

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.