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.     

The addition of voice prompts to audiovisual feedback and debriefing does not modify CPR quality or outcomes in out of hospital cardiac arrest--a prospective, randomized trial

Aims

Chest compression quality is a determinant of survival from out-of-hospital cardiac arrest (OHCA). ERC 2005 guidelines recommend the use of technical devices to support rescuers giving compressions. This prospective randomized study reviewed influence of different feedback configurations on survival and compression quality.

Materials and methods

312 patients suffering an OHCA were randomly allocated to two different feedback configurations. In the limited feedback group a metronome and visual feedback was used. In the extended feedback group voice prompts were added. A training program was completed prior to implementation, performance debriefing was conducted throughout the study.

Results

Survival did not differ between the extended and limited feedback groups (47.8% vs 43.9%, p = 0.49). Average compression depth (mean ± SD: 4.74 ± 0.86 cm vs 4.84 ± 0.93 cm, p = 0.31) was similar in both groups. There were no differences in compression rate (103 ± 7 vs 102 ± 5 min(−1), p = 0.74) or hands-off fraction (16.16% ± 0.07 to 17.04% ± 0.07, p = 0.38). Bystander CPR, public arrest location, presenting rhythm and chest compression depth were predictors of short term survival (ROSC to ED).

Conclusions

Even limited CPR-feedback combined with training and ongoing debriefing leads to high chest compression quality. Bystander CPR, location, rhythm and chest compression depth are determinants of survival from out of hospital cardiac arrest. Addition of voice prompts does neither modify CPR quality nor outcome in OHCA. CC depth significantly influences survival and therefore more focus should be put on correct delivery. Further studies are needed to examine the best configuration of feedback to improve CPR quality and survival.

Registration

ClinicalTrials.gov (NCT00449969), http://www.clinicalTrials.gov.     

Tertiary centres have improved survival compared to other hospitals in the Copenhagen area after out-of-hospital cardiac arrest

Aims

Out-of-hospital cardiac arrest (OHCA) has been reported to carry very varying morbidity and mortality. However, it remains unclear whether this is caused by intrinsic factors of the OHCA or due to the level of in-hospital care. The aim of this study is to compare 30-day and long-term mortality after OHCA at tertiary heart centres and non-tertiary university hospitals.

Methods and results

Data from the Copenhagen OHCA registry from June 2002 through December 2010 included a total of 1218 consecutive patients treated by the same mobile emergency care unit (MECU) with either return of spontaneous circulation (ROSC) or on-going resuscitation (n = 53) at hospital arrival. The MECU transported patients to the nearest hospital unless an ECG on scene suggested ST-segment elevation myocardial infarction, in which case patients were transported to the nearest tertiary centre for acute coronary angiography. Therefore, patients with ST-elevation myocardial infarction (n = 198) were excluded from the analysis. 30-day mortality was 56% vs. 76% and long term (up to 8 years) mortality was 78% vs. 94% for tertiary and non-tertiary hospitals, respectively, both p < 0.001. Multivariate analysis showed that admission to a non-tertiary hospital was independently associated with increased risk of death (HR = 1.32, 95% CI: 1.09–1.59, p = 0.004). Exclusion of patients with on-going resuscitation at admission resulted in HR = 1.34 (1.11–1.62), p = 0.003. A matched pair propensity score analysis of 255 patients confirmed the results of the proportional hazard analysis (HR = 1.35, 95% CI: 1.11–1.65 p = 0.003).

Conclusion

Admission to tertiary centres is associated with lower mortality rates after OHCA compared with non-tertiary hospitals.     

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.     

The clinical significance of a failed initial intubation attempt during emergency department resuscitation of out-of-hospital cardiac arrest patients

Objective

Advanced airway management is one of the fundamental skills of advanced cardiac life support (ACLS). A failed initial intubation attempt (FIIA) is common and has shown to be associated with adverse events. We analysed the association between FIIA and the overall effectiveness of ACLS.

Methods

Using emergency department (ED) out-of-hospital cardiac arrest (OHCA) registry data from 2008 to 2012, non-traumatic ED-resuscitated adult OHCA patients on whom endotracheal intubation was initially tried were identified. Prehospital and demographic factors and patient outcomes were retrieved from the registry. The presence of a FIIA was determined by reviewing nurse-documented CPR records. The primary outcome was achieving a return of spontaneous circulation (ROSC). The secondary outcomes were time to ROSC and the ROSC rate during the first 30 min of ED resuscitation.

Results

The study population (n = 512) was divided into two groups based on the presence of a FIIA (N = 77). Both groups were comparable without significant differences in demographic or prehospital factors. In the FIIA group, the unadjusted and adjusted odds ratios (ORs) for achieving a ROSC were 0.50 (95% confidence interval [CI], 0.31–0.81) and 0.40 (95% CI, 0.23–0.71), respectively. Multivariable median regression analysis revealed that FIIA was associated with an average delay of 3 min in the time to ROSC (3.08; 95% CI, 0.08–5.80). Competing risk regression analysis revealed a significantly slower ROSC rate during the first 15 min (adjusted subhazard ratio, 0.52; 95% CI, 0.35–0.79) in the FIIA group.

Conclusion

FIIA is an independent risk factor for the decreased effectiveness of ACLS.     

Effect of cardiopulmonary resuscitation on restoration of myocardial ATP in prolonged ventricular fibrillation

Background

There has been controversy over whether a short period of cardiopulmonary resuscitation (CPR) prior to defibrillation improves survival in patients who experienced a sudden cardiac arrest. However, there have been no reports about whether CPR restores the myocardial energy source during prolonged ventricular fibrillation (VF). The aim of this study is to investigate the effect of CPR in restoring myocardial high energy phosphates during prolonged VF.

Methods and results

Seventy-two adult male Sprague-Dawley rats were used in this study. Baseline adenosine triphosphate (ATP) and adenosine diphosphate (ADP) prior to induction of VF were measured in nine rats, the No-VF group. Sixty-three rats were subjected to 4 min of untreated VF. Animals were then randomized into two groups: No-CPR (n = 37) and CPR (n = 26). In the No-CPR group, ATPs and ADPs were measured at 4 min (No-CPR4), 6 min (No-CPR6), 8 min (No-CPR8) or 10 min (No-CPR10) after the induction of VF. The CPR group received 2 min (CPR2), 4 min (CPR4) or 6 min (CPR6) of mechanical chest compressions before ATP was measured.Myocardial ATP (nmol/mg protein) was decreased as VF duration was prolonged (No-VF: 5.49 ± 1.71, No-CPR4: 4.27 ± 1.58, No-CPR6: 4.13 ± 1.31, No-CPR8: 3.77 ± 1.42, No-CPR10: 3.52 ± 0.90, p < 0.05 between each of No-CPRs vs. No-VF). Two minutes of CPR restored myocardial ATP to the level of No-VF group (5.27 ± 1.67 nmol/mg protein in CPR2, p > 0.05 vs. No-VF group). However, myocardial ATP (nmol/mg protein) decreased if the duration of CPR was longer than 2 min (CPR4: 3.77 ± 1.05, CPR6: 3.49 ± 1.08, p < 0.05 between CPR4 and CPR6 vs. No-VF).

Conclusions

CPR for 2 min helps to maintain myocardial ATP after prolonged VF.     

Myocardial infarction is a frequent cause of exercise-related resuscitated out-of-hospital cardiac arrest in a general non-athletic population

Background

Performing exercise is shown to prevent cardiovascular disease, but the risk of an out-of-hospital cardiac arrest (OHCA) is temporarily increased during strenuous activity. We examined the etiology and outcome after successfully resuscitated OHCA during exercise in a general non-athletic population.

Methods

Consecutive patients with OHCA were admitted with return of spontaneous circulation (ROSC) or on-going resuscitation at hospital arrival (2002–2011). Patient charts were reviewed for post-resuscitation data. Exercise was defined as moderate/vigorous physical activity.

Results

A total of 1393 OHCA-patients were included with 91(7%) arrests occurring during exercise. Exercise-related OHCA-patients were younger (60 ± 13 vs. 65 ± 15, p < 0.001) and predominantly male (96% vs. 69%, p < 0.001). The arrest was more frequently witnessed (94% vs. 86%, p = 0.02), bystander CPR was more often performed (88% vs. 54%, p < 0.001), time to ROSC was shorter (12 min (IQR: 5–19) vs. 15 (9–22), p = 0.007) and the primary rhythm was more frequently shock-able (91% vs. 49%, p < 0.001) compared to non-exercise patients. Cardiac etiology was the predominant cause of OHCA in both exercise and non-exercise patients (97% vs. 80%, p < 0.001) and acute coronary syndrome was more frequent among exercise patients (59% vs. 38%, p < 0.001). One-year mortality was 25% vs. 65% (p < 0.001), and exercise was even after adjustment associated with a significantly lower mortality (HR = 0.40 (95%CI: 0.23–0.72), p = 0.002).

Conclusions

OHCA occurring during exercise was associated with a significantly lower mortality in successfully resuscitated patients even after adjusting for confounding factors. Acute coronary syndrome was more common among exercise-related cardiac arrest patients.     

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.     

Ethyl pyruvate enhances intra-resuscitation hemodynamics in prolonged ventricular fibrillation arrest

Aims

As the duration of untreated cardiac arrest increases, the effectiveness of standard therapies declines, and may be more harmful than helpful. We investigated the hemodynamic, metabolic and anti-inflammatory effects of Ringer's ethyl pyruvate solution (REPS) versus Ringer's solution (RS) in the acute model of prolonged porcine arrest.

Methods

Seventeen mixed-breed swine were induced into ventricular fibrillation (VF) and left untreated for 8 min. CPR was begun using a mechanical chest compression device at a rate of 100 per minute. At the onset of CPR, animals were randomly assigned to treatment with either 25 mL/kg of RS or 25 mL/kg of REPS containing 40 mg/kg of ethyl pyruvate, infused over 5 min in blinded fashion. CPR continued with administration of a drug cocktail at 2 min and the first rescue shock was delivered at minute 13 of VF. Animals having ROSC were supported with standardized care for 2 h.

Results

Both groups had 100% ROSC and 100% 2-h survival. The REPS group exhibited higher median CPP (27.3 mmHg) than the control group (16.5 mmHg) by 3 min of CPR, which continued throughout the duration of CPR (p = 0.02). The median time to hypotension following ROSC was 9.64 min in the REPS group and 7.25 min in controls (p = 0.04) and there was a non-significant trend of decreased use of vasopressors for the duration of resuscitation. There was no difference in systemic or cerebral metabolism between groups. There were non-significant trends of decreased IL-6, increased Il-10 and decreased mesenteric bacterial colony growth in those treated with REPS when compared to RS.

Conclusions

The administration of REPS with CPR significantly improved intra- and post-resuscitation hemodynamics in this swine model of prolonged cardiac arrest, but did not definitely change the metabolic or inflammatory profile during the acute resuscitation period.     

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.     

Aspects on the increase in bystander CPR in Sweden and its association with outcome

Aim

To describe changes in the proportion of bystanders performing cardiopulmonary resuscitation (CPR) in out of hospital cardiac arrest (OHCA) in Sweden and to study the impact of bystander CPR on ventricular fibrillation and on survival during various times.

Patients and methods

All patients who suffered from OHCA in Sweden in whom CPR was attempted and who were included in the Swedish cardiac arrest register (SCAR) between 1992 and 2005. Crew witnessed cases were excluded.

Results

In all 34,125 patients were included in the survey. Among witnessed OHCA the proportion of patients receiving bystander CPR increased from 40% in 1992 to 55% in 2005 (p < 0.0001). In non-witnessed OHCA the corresponding proportion increased from 22% to 44% (p < 0.0001). There was a significant increase in bystander CPR regardless of age, sex and place. The increase was only found when CPR was performed by lay persons (21% in 1992 to 40% in 2005; p < 0.0001). Bystander CPR was associated with an increased proportion of patients found in a shockable rhythm and a lower number of shocks to receive return of spontaneous circulation. Bystander CPR was associated with a similar increase in survival early and late in the evaluation.

Conclusion

There was a marked increase in bystander CPR in OHCA, when performed by lay persons, during the last 14 years in Sweden. Bystander CPR was associated with positive effects both on ventricular fibrillation and 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.     

Perfluorocarbon induced intra-arrest hypothermia does not improve survival in a swine model of asphyxial cardiac arrest

Background

Pulseless electrical activity is an important cause of cardiac arrest. Our purpose was to determine if induction of hypothermia with a cold perfluorocarbon-based total liquid ventilation (TLV) system would improve resuscitation success in a swine model of asphyxial cardiac arrest/PEA.

Methods

Twenty swine were randomly assigned to control (C, no ventilation, n = 11) or TLV with pre-cooled PFC (n = 9) groups. Asphyxia was induced by insertion of a stopper into the endotracheal tube, and continued in both groups until loss of aortic pulsations (LOAP) was reached, defined as a pulse pressure less than 2 mmHg. The TLV animals underwent asphyxial arrest for an additional 2 min after LOAP, followed by 3 min of hypothermia, prior to starting CPR. The C animals underwent 5 min of asphyxia beyond LOAP. Both groups then underwent CPR for at least 10 min. The endpoint was the resumption of spontaneous circulation maintained for 10 min.

Results

Seven of 9 animals achieved resumption of spontaneous circulation (ROSC) in the TLV group vs. 5 of 11 in the C group (p = 0.2). The mean pulmonary arterial temperature was lower in total liquid ventilation animals starting 4 min after induction of hypothermia (TLV 36.3 ± 0.2 °C vs. C 38.1 ± 0.2 °C, p < 0.0001). Arterial pO₂ was higher in total liquid ventilation animals at 2.5 min of CPR (TLV 76 ± 12 mmHg vs. C 44 ± 2 mmHg; p = 0.03).

Conclusion

Induction of moderate hypothermia using perfluorocarbon-based total liquid ventilation did not improve ROSC success in this model of asphyxial cardiac arrest.     

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.     

Effects of repetitive or intensified instructions in telephone assisted,bystander cardiopulmonary resuscitation: An investigator-blinded, 4-armed,randomized, factorial simulation trial

Background

Compression depth is frequently suboptimal in cardiopulmonary resuscitation (CPR). We investigated effects of intensified wording and/or repetitive target depth instructions on compression depth in telephone-assisted, protocol driven, bystander CPR on a simulation manikin.

Methods

Thirty-two volunteers performed 10 min of compression only-CPR in a prospective, investigator-blinded, 4-armed, factorial setting. Participants were randomized either to standard wording (“push down firmly 5 cm”), intensified wording (“it is very important to push down 5 cm every time”) or standard or intensified wording repeated every 20 s. Three dispatchers were randomized to give these instructions. Primary outcome was relative compression depth (absolute compression depth minus leaning depth). Secondary outcomes were absolute distance, hands-off times as well as BORG-scale and nine-hole peg test (NHPT), pulse rate and blood pressure to reflect physical exertion. We applied a random effects linear regression model.

Results

Relative compression depth was 35 ± 10 mm (standard) versus 31 ± 11 mm (intensified wording) versus 25 ± 8 mm (repeated standard) and 31 ± 14 mm (repeated intensified wording).Adjusted for design, body mass index and female sex, intensified wording and repetition led to decreased compression depth of 13 (95%CI −25to −1) mm (p = 0.04) and 9 (95%CI −21 to 3) mm (p = 0.13), respectively. Secondary outcomes regarding intensified wording showed significant differences for absolute distance (43 ± 2 versus 20 (95%CI 3–37) mm; p = 0.01) and hands-off times (60 ± 40 versus 157 (95%CI 63–251) s; p = 0.04).

Conclusion

In protocol driven, telephone-assisted, bystander CPR, intensified wording and/or repetitive target depth instruction will not improve compression depth compared to the standard instruction.     

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.     

Traumatic out-of-hospital cardiac arrests in Melbourne, Australia

Introduction

Many consider attempted resuscitation for traumatic out-of-hospital cardiac arrest (OHCA) futile. This study aims to describe the characteristics and profile of adult traumatic OHCA.

Methods

The Victorian Ambulance Cardiac Arrest Registry (VACAR) was used to identify all trauma related cases of OHCA in patients aged ≥16 years.

Results

Between 2000 and 2009, EMS attended 33,178 OHCAs of which 2187 (6.6%) had a traumatic aetiology. The median age (IQR) of traumatic OHCA cases was 36 (25–55) years and 1612 were male (77.5%). Bystander CPR was performed in 201 cases (10.2%) with median (IQR) EMS response time 8 (6–11) min. The first recorded rhythm by EMS was asystole seen in 1650 (75.4%), PEA in 294 (13.4%) cases and VF in 35 cases (1.6%). Cardiac output was present in 208 (9.5%) cases who subsequently had an EMS witnessed OHCA. EMS attempted resuscitation in 545 (24.9%) patients of whom 84 (15.4%) achieved ROSC and were transported, and 27 (5.1%) survived to hospital discharge; 107 were transported with CPR of whom 8 (7.4%) survived to hospital discharge. Where EMS attempted resuscitation in traumatic OHCAs, survival for VF was 11.8% (n = 4), PEA 5.1% (n = 10) and asystole 2.4% (n = 3). In EMS witnessed traumatic OHCA, resuscitation was attempted in 175 cases (84.1%), 35 (16.8%) patients achieved sustained ROSC before transport of whom 5 (14%) survived to leave hospital and 60 (28.8%) were transported with CPR of whom 6 (10%) survived to leave hospital. Compared to OHCA cases with ‘presumed cardiac’ aetiology traumatic OHCAs were younger [median years (IQR): 36 (25–55) vs 74 (61–82)], had resuscitation attempted less (25% vs 48%), were less likely to have a shockable rhythm (1.6% vs 17.1%), were more likely to be witnessed (62.8% vs 38.1%) and were less likely to receive bystander CPR (10.2% vs 25.5%) (p < 0.001, respectively). Multivariate logistic regression identified factors associated with EMS decision to attempt resuscitation. The odds ratio [OR (95% CI)] for ‘presence of bystander CPR’ was 5.94 (4.11–8.58) and for ‘witnessed arrest’ was 2.60 (1.86–3.63).

Conclusion

In this paramedic delivered EMS attempted resuscitation was not always futile in traumatic OHCA with a survival of 5.1%. The quality of survival needs further study.     

The impact of therapeutic hypothermia on neurological function and quality of life after cardiac arrest

Aims

To assess the impact of therapeutic hypothermia on cognitive function and quality of life in comatose survivors of out of Hospital Cardiac arrest (OHCA).

Methods

We prospectively studied comatose survivors of OHCA consecutively admitted in a 4-year period. Therapeutic hypothermia was implemented in the last 2-year period, intervention period (n = 79), and this group was compared to patients admitted the 2 previous years, control period (n = 77). We assessed Cerebral Performance Category (CPC), survival, Mini Mental State Examination (MMSE) and self-rated quality of life (SF-36) 6 months after OHCA in the subgroup with VF/VT as initial rhythm.

Results

CPC in patients alive at hospital discharge was significantly better in the intervention period with a CPC of 1–2 in 97% vs. 71% in the control period, p = 0.003, corresponding to an adjusted odds ratio of a favourable cerebral outcome of 17, p = 0.01. No significant differences were found in long-term survival (57% vs. 56% alive at 30 months), MMSE, or SF-36. Therapeutic hypothermia (hazard ratio: 0.15, p = 0.007) and bystander CPR (hazard ratio 0.19, p = 0.002) were significantly related to survival in the intervention period.

Conclusion

CPC at discharge from hospital was significantly improved following implementation of therapeutic hypothermia in comatose patients resuscitated from OCHA with VF/VT. However, significant improvement in survival, cognitive status or quality of life could not be detected at long-term follow-up.     

New treatment bundles improve survival in out-of-hospital cardiac arrest patients: A historical comparison

Introduction

Before the introduction of the new international cardiac arrest treatment guidelines in 2005, patients with out-of-hospital cardiac arrest (OHCA) of cardiac origin in Northern Italy had very poor prognosis. Since 2006, a new bundle of care comprising use of automated external defibrillators (AEDs) and therapeutic hypothermia (TH) was started, while extracorporeal CPR program (ECPR) for selected refractory CA and dispatcher-assisted cardio-pulmonary resuscitation (CPR) was started in January 2010.

Objectives

We hypothesized that a program of bundled care might improve outcome of OHCA patients.

Methods

We analyzed data collected in the OHCA registry of the MB area between September 2007 and August 2011 and compared this with data from 2000 to 2003.

Results

Between 2007 and 2011, 1128 OHCAs occurred in the MB area, 745 received CPR and 461 of these had a CA of presumed cardiac origin. Of these, 125 (27%) achieved sustained ROSC, 60 (13%) survived to 1 month, of whom 51 (11%) were discharged from hospital with a good neurological outcome (CPC ≤ 2), and 9 with a poor neurological outcome (CPC > 2).Compared with data from the 2000 to 2003 periods, survival increased from 5.6% to 13.01% (p < 0.0001). In the 2007–2011 group, low-flow time and bystander CPR were independent markers of survival.

Conclusions

OHCA survival has improved in our region. An increased bystander CPR rate associated with dispatcher-assisted CPR was the most significant cause of increased survival, but duration of CA remains critical for patient outcome.