Treatment of non-traumatic out-of-hospital cardiac arrest with active compression decompression cardiopulmonary resuscitation plus an impedance threshold device

Background

A recent out-of-hospital cardiac arrest (OHCA) clinical trial showed improved survival to hospital discharge (HD) with favorable neurologic function for patients with cardiac arrest of cardiac origin treated with active compression decompression cardiopulmonary resuscitation (CPR) plus an impedance threshold device (ACD + ICD) versus standard (S) CPR. The current analysis examined whether treatment with ACD + ITD is more effective than standard (S-CPR) for all cardiac arrests of non-traumatic origin, regardless of the etiology.

Methods

This is a secondary analysis of data from a randomized, prospective, multicenter, intention-to-treat, OHCA clinical trial. Adults with presumed non-traumatic cardiac arrest were enrolled and followed for one year post arrest. The primary endpoint was survival to hospital discharge (HD) with favorable neurologic function (Modified Rankin Scale score ≤ 3).

Results

Between October 2005 and July 2009, 2738 patients were enrolled (S-CPR = 1335; ACD + ITD = 1403). Survival to HD with favorable neurologic function was greater with ACD + ITD compared with S-CPR: 7.9% versus 5.7%, (OR 1.42, 95% CI 1.04, 1.95, p = 0.027). One-year survival was also greater: 7.9% versus 5.7%, (OR 1.43, 95% CI 1.04, 1.96, p = 0.026). Nearly all survivors in both groups had returned to their baseline neurological function by one year. Major adverse event rates were similar between groups.

Conclusions

Treatment of out-of-hospital non-traumatic cardiac arrest patients with ACD + ITD resulted in a significant increase in survival to hospital discharge with favorable neurological function when compared with S-CPR. A significant increase survival rates was observed up to one year after arrest in subjects treated with ACD + ITD, regardless of the etiology of the cardiac arrest.     

Evaluation of an impedance threshold device in patients receiving active compression-decompression cardiopulmonary resuscitation for out of hospital cardiac arrest

AIMS: The purpose of this multicentre clinical randomized controlled blinded prospective trial was to determine whether an inspiratory impedance threshold device (ITD), when used in combination with active compression-decompression (ACD) cardiopulmonary resuscitation (CPR), would improve survival rates in patients with out-of-hospital cardiac arrest. METHODS AND RESULTS: Patients were randomized to receive either a sham (n = 200) or an active impedance threshold device (n = 200) during advanced cardiac life support performed with active compression-decompression cardiopulmonary resuscitation. The primary endpoint of this study was 24 h survival. The 24 h survival rates were 44/200 (22%) with the sham valve and 64/200 (32%) with the active valve (P = 0.02). The number of patients who had a return of spontaneous circulation (ROSC), intensive care unit (ICU) admission, and hospital discharge rates was 77 (39%), 57 (29%), and 8 (4%) in the sham valve group versus 96 (48%) (P = 0.05), 79 (40%) (P = 0.02), and 10 (5%) (P = 0.6) in the active valve group. Six out of ten survivors in the active valve group and 1/8 survivors in the sham group had normal neurological function at hospital discharge (P = 0.1). CONCLUSION: The use of an impedance valve in patients receiving active compression-decompression cardiopulmonary resuscitation for out-of-hospital cardiac arrest significantly improved 24 h survival rates.     

Resuscitation Outcomes Consortium (ROC) PRIMED cardiac arrest trial methods part 1: rationale and methodology for the impedance threshold device (ITD) protocol

AIM: The primary aim of this study is to compare survival to hospital discharge with a modified Rankin score (MRS)< or =3 between standard cardiopulmonary resuscitation (CPR) plus an active impedance threshold device (ITD) versus standard CPR plus a sham ITD in patients with out-of-hospital cardiac arrest. Secondary aims are to compare functional status and depression at discharge and at 3 and 6 months post-discharge in survivors. MATERIALS AND METHODS: Design: Prospective, double-blind, randomized, controlled, clinical trial. Population: Patients with non-traumatic out-of-hospital cardiac arrest treated by emergency medical services (EMS) providers. Setting: EMS systems participating in the Resuscitation Outcomes Consortium. Sample size: Based on a one-sided significance level of 0.025, power=0.90, a survival with MRS< or =3 to discharge rate of 5.33% with standard CPR and sham ITD, and two interim analyses, a maximum of 14,742 evaluable patients are needed to detect a 6.69% survival with MRS< or =3 to discharge with standard CPR and active ITD (1.36% absolute survival difference). CONCLUSION: If the ITD demonstrates the hypothesized improvement in survival, it is estimated that 2700 deaths from cardiac arrest per year would be averted in North America alone.     

Sodium nitroprusside enhanced cardiopulmonary resuscitation (SNPeCPR) improves vital organ perfusion pressures and carotid blood flow in a porcine model of cardiac arrest

Purpose of the study

To describe a new method of CPR that optimizes vital organ perfusion pressures and carotid blood flow. We tested the hypothesis that a combination of high dose sodium nitroprusside (SNP) as well as non-invasive devices and techniques known independently to enhance circulation would significantly improve carotid blood flow (CBF) and return of spontaneous circulation (ROSC) rates in a porcine model of cardiac arrest.

Methods

15 isofluorane anesthetized pigs (30 ± 1 kg), after 6 min of untreated ventricular fibrillation, were subsequently randomized to receive either 15 min of standard CPR (S-CPR) (8 animals) or 5 min epochs of S-CPR followed by active compression–decompression (ACD) + inspiratory impedance threshold device (ITD) CPR followed by ACD + ITD + abdominal binding (AB) with 1 mg of SNP administered at minutes 2, 7, 12 of CPR (7 animals). Primary endpoints were CBF and ROSC rates. ANOVA and Fisher's exact test were used for comparisons.

Results/conclusion

There was significant improvement in the hemodynamic parameters in the SNP animals. ROSC was achieved in 7/7 animals that received SNP and in 2/8 in the S-CPR (p = 0.007). CBF and end tidal CO₂ (ETCO₂) were significantly higher in the ACD + ITD + AB + SNP (SNPeCPR) animals during CPR. Bolus doses of SNP, when used in conjunction with ACD + ITD + AB CPR, significantly improve CBF and ROSC rates compared to S-CPR.     

Active compression-decompression cardiopulmonary resuscitation: a population-based, prospective randomised clinical trial in out-of-hospital cardiac arrest

Different mechanical devices have been developed to improve cardiopulmonary resuscitation (CPR). The aim of this study was to evaluate active compression-decompression (ACD) CPR applied by Emergency Medical Service (EMS) in a defined population. The Trondheim region EMS (population 154,000) employs simultaneous paramedic and physician response. Upon decision to treat, patients with cardiac arrest of presumed cardiac origin were allocated to ACD CPR (CardioPump) or standard CPR by drawing a random number tag. Outcome in each patient was determined on a 5 point ordinal scale (no clinical improvement = 1, survival to discharge = 5). In 4 years, CPR was attempted in a total of 431 cardiac arrests, 54 patients (13%) survived to discharge; 302 patients with similar baseline characteristics were randomised. The prevalence of bystander CPR was 57% and the median call-arrival interval 9 min. By intention to treat, the mean score in the standard CPR group was 2.51 and 17/145 patients (12%) survived. The mean score in the ACD CPR group was 2.53 (P = 0.9) and 20/157 patients (13%) survived. Cerebral outcome was similar in the two groups. Among the 145 ACD patients, the technique was successfully applied in 110, found inapplicable in 35 and in seven patients chest compressions were unnecessary. This is the largest, single-centre, randomised, population based study of ACD CPR in out-of-hospital cardiac arrest to date. Even when considering a wider outcome spectrum than crude survival, we found no evidence of clinical benefit. In a quarter of cases ACD CPR was inapplicable, further limiting its potential usefulness.     

Effect of active compression-decompression resuscitation (ACD-CPR) on survival: a combined analysis using individual patient data.

Active compression decompression resuscitation (ACD-CPR) has been developed as an alternative to standard cardiopulmonary resuscitation (S-CPR). To determine the effect of ACD-CPR on survival and neurologic outcome in patients with out-of-hospital cardiac arrest, this combined analysis involved individual patient data from 2866 patients from seven separate randomized prospective prehospital studies who had received ACD-CPR or S-CPR after out-of-hospital cardiac arrest in seven international sites. Significant improvement in 1-h survival (odds ratio (OR) = 0.83; confidence interval (CI): 0.695-0.99; P < 0.05) was found with ACD-CPR (n = 1410) versus S-CPR (n = 1456). The odds ratio for hospital discharge after ACD-CPR was similar (OR = 0.82; CI: 0.609-1.107, P = NS), but this finding was not statistically significant. Using the chi2-test for trend, there was a significant improvement in overall survival with ACD-CPR (P < 0.05) versus S-CPR. This improvement was largely due to the influence of results from one study site. Neurological outcome and complication rates were comparable between groups. Further study is needed to determine which emergency medical services systems may benefit from out-of-hospital use of ACD-CPR.     

Effects of an Impedance Threshold Device on Hemodynamics andRestoration of Spontaneous Circulation in Prolonged Porcine Ventricular Fibrillation

Background. An impedance threshold device (ITD) has been designed to enhance circulation during CPR by creating a negative intrathoracic pressure during the relaxation phase of chest compression. Hypothesis. We sought to determine the effects of the ITD on coronary perfusion pressure (CPP), return of spontaneous circulation (ROSC), andshort-term survival (20 minutes after ROSC). We hypothesized that the ITD would improve all 3 variables when compared to standard CPR. Methods. Using a case-control design nested within a randomized primary study, we compared CPR with the ITD (ITD-CPR) to standard CPR without the device (S-CPR). We systematically assigned 36 domestic swine, weighing 23–29 kg, (18 per group) to resuscitation with either ITD-CPR or S-CPR after 8 minutes of untreated ventricular fibrillation (VF). At minute 8, mechanical chest compression andventilation began, anddrugs (0.1 mg/kg epinephrine, 40U vasopressin, 1.0 mg propranolol, 1 mEq/kg sodium bicarbonate) were given. The first rescue shock (150J biphasic) was delivered at minute 11 of VF. We recorded CPP, ROSC (systolic pressure > 80 mmHg sustained for 60 s continuously), andsurvival. Data were analyzed with Fisher's exact test andgeneralized estimating equations (GEE), with alpha = 0.05. Results. We analyzed 3,150 compressions. CPP for the ITD-CPR group (28.1 mmHg [95% CI 27–29.3 mmHg]), did not differ from the S-CPR group (32.3 mmHg [95% CI 31.2–33.4 mmHg]). ROSC occurred in 6/18 (33%) animals in the ITD-CPR, and14/18 (78%) in the S-CPR group (p = 0.02). Survival occurred in 3/18 (17%) ITD-CPR and13/18 (72%) S-CPR group (p = 0.003). Conclusions. ITD-CPR did not improve CPP compared to S-CPR. ROSC andsurvival were significantly lower with ITD-CPR.     

Use of an inspiratory impedance threshold device on a facemask and endotracheal tube to reduce intrathoracic pressures during the decompression phase of active compression-decompression cardiopulmonary resuscitation

INTRODUCTION: Use of an inspiratory impedance threshold device (ITD) significantly increases coronary perfusion pressures and survival in patients ventilated with an endotracheal tube (ETT) during active compression-decompression cardiopulmonary resuscitation. We tested the hypothesis that the ITD could lower intratracheal pressures when attached to either a facemask or ETT. METHODS: An active and sham ITD were randomly applied first to a facemask and then to an ETT during active compression-decompression cardiopulmonary resuscitation in 13 out-of-hospital cardiac arrest patients in a randomized, double-blinded, prospective clinical trial. The compression-to-bag-valve ventilation ratio was 15:2. Airway pressures (surrogate for intrathoracic pressure) were measured with a pressure transducer. A sham and an active ITD were used for 1 min each in a randomized order, first on a facemask and then on an ETT. Statistical analyses were made using Friedman's and Wilcoxon's rank-sum tests. RESULTS: For the primary end point, mean +/- sd maximum negative intrathoracic pressures (mm Hg) during the decompression phase of cardiopulmonary resuscitation were -1.0 +/- 0.73 mm Hg with a sham vs. -4.6 +/- 3.7 mm Hg with an active ITD on the facemask (p = .003) and -1.3 +/- 1.3 mm Hg with a sham ITD vs. -7.3 +/- 4.5 mm Hg with an active ITD on an ETT (p = .0009). Decompression phase airway pressures with the facemask and ETT were not statistically different. CONCLUSIONS: Use of an active ITD attached to a facemask or an ETT resulted in a significantly lower negative intratracheal pressure during the decompression phase of active compression-decompression cardiopulmonary resuscitation when compared with controls. Airway pressures with an ITD on either a facemask or ETT were similar. The ITD-facemask combination was practical and enables rapid deployment of this life-saving technology.     

心肺复苏的质量对复苏后炎症反应的影响

目的 评价临床上常见的不标准心肺复苏(N-CPR)和2005年国际CPR指南推荐的标准心肺复苏(S-CPR)对心脏停搏(CA)猪复苏后炎症反应的影响.方法 18头猪被随机均分成两组,经麻醉、插管、机械通气后,应用程控刺激方法制备心室纤颤(VF)模型.S-CPR组应用2005年指南推荐的CPR方式;N-CPR组模拟临床上经常出现的低质量CPR方式.VF 4 min后开始进行CPR,CPR 9 min后进行电除颤及高级生命支持,自主循环恢复(ROSC)后进行各项指标观察.24 h仍存活的猪经处死后取脑、心、肝、肾组织,应用免疫组化法检测核转录因子-kB(NF-kB)的表达.实验期间连续监测CPR后3、6和9 min的血流动力学变化,并抽取基础状态、CPR 9 rain、ROSC 4 h的静脉血,测定血清肿瘤坏死因子-a(TNF-α)、白细胞介素-1β(IL-1β)的浓度.结果 与N-CPR组比较,S-CPR组ROSC率(22.2%比88.9%)及24 h存活率(22.2%比88.9%)明显提高(P均＜0.05);CPR后3、6和9 min心排血量(CO)和平均动脉压(MAP)也均显著升高(P均＜0.01);并且CPR后9 min和ROSC 4 h血清促炎症因子TNF-α、IL-1β]水平和各组织NF-kB表达程度均降低.结论 高质量的CPR后不仅能提高CA猪的生存率,也明显改善CPR后的炎症反应.     

Effect of an inspiratory impedance threshold device on hemodynamics during conventional manual cardiopulmonary resuscitation

BACKGROUND: In animals in cardiac arrest, an inspiratory impedance threshold device (ITD) has been shown to improve hemodynamics and neurologically intact survival. The objective of this study was to determine whether an ITD would improve blood pressure (BP) in patients receiving CPR for out-of-hospital cardiac arrest. METHODS: This prospective, randomized, double-blind, intention-to-treat study was conducted in the Milwaukee, WI, emergency medical services (EMS) system. EMS personnel used an active (functional) or sham (non-functional) ITD on a tracheal tube on adults in cardiac arrest of presumed cardiac etiology. Care between groups was similar except for ITD type. Low dose epinephrine (1mg) was used per American Heart Association Guidelines. Femoral arterial BP (mmHg) was measured invasively during CPR. RESULTS: Mean+/-S.D. time from ITD placement to first invasive BP recording was approximately 14 min. Twelve patients were treated with a sham ITD versus 10 patients with an active ITD. Systolic BPs (mean+/-S.D.) [number of patients treated at given time point] at T = 0 (time of first arterial BP measurement), and T=2, 5 and 7 min were 85+/-29 [10], 85+/-23 [10], 85+/-16 [9] and 69+/-22 [8] in the group receiving an active ITD compared with 43+/-15 [12], 47+/-16 [12], 47+/-20 [9], and 52+/-23 [9] in subjects treated with a sham ITD, respectively (p < 0.01 for all times). Diastolic BPs at T = 0, 2, 5 and 7 min were 20+/-12, 21+/-13, 23+/-15 and 25+/-14 in the group receiving an active ITD compared with 15+/-9, 17+/-8, 17+/-9 and 19+/-8 in subjects treated with a sham ITD, respectively (p = NS for all times). No significant adverse device events were reported. CONCLUSIONS: Use of the active ITD was found to increase systolic pressures safely and significantly in patients in cardiac arrest compared with sham controls.     

Alternative cardiopulmonary resuscitation devices

Cardiac arrest survival rates remain low despite increased access to advanced cardiac life support. Survival from cardiac arrest is, at least in part, related to the perfusion pressures and blood flow achieved during cardiopulmonary resuscitation (CPR). A number of alternative CPR devices have been developed that aim to improve the perfusion pressures and/or blood flow achieved during CPR. Active compression-decompression CPR devices are by far the most studied alternative CPR devices, but the results have been inconsistent and conflicting. A number of other devices, including the inspiratory impedance threshold valve, minimally invasive direct cardiac massage, phased chest and abdominal compression-decompression CPR, and vest CPR, are all capable of improving perfusion pressures and/or blood flow compared with standard external chest compressions. However, no convincing human outcome data has been produced yet for any of these devices. Although an interesting area of research, none of the alternative CPR devices convincingly improve long-term patient outcomes.     

Long-term prognosis after out-of-hospital cardiac arrest and primary percutaneous coronary intervention

AIMS: To study the long-term survival after out-of-hospital cardiac arrest and successful cardiopulmonary resuscitation (CPR) in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). MATERIAL AND METHODS: In-hospital and 2-year survival of 40 patients treated with primary PCI after out-of-hospital cardiac arrest and STEMI was compared with that of a reference group of 325 STEMI patients, without cardiac arrest, also treated with primary PCI in the same period. RESULTS: In the group with out-of-hospital cardiac arrest, both in-hospital and 2-year mortality was 27.5%. In the reference group, in-hospital and 2-year mortality was 4.9 and 7.1%, respectively. After discharge from hospital there was no significant difference in mortality between the groups. CONCLUSION: Long-term prognosis is good in selected patients after successful out-of-hospital CPR and STEMI treated with primary PCI.     

Evaluation of the use of automatic external defibrillation in out-of-hospital cardiac arrest in Hong Kong.

A retrospective 6-month audit of out-of-hospital cardiac arrests in Hong Kong following the introduction of automatic external defibrillators is presented. During the 6-month period from 1 July 1995 to 31 December 1995, resuscitation was attempted on 754 patients. Of the 744 patients with cardiac arrest whose records were available, 53.6% had a witnessed arrest. Few cardiac arrest patients (8.9%) received bystander cardiopulmonary resuscitation (CPR) and the majority (80%) of arrests occurred at home. Six hundred and forty-three (86.4%) patients were declared dead on arrival at hospital or in the Accident and Emergency department; 89 (12%) died in hospital and only 12 (1.6%) were discharged alive. The average ambulance response interval (call receipt to arrival of ambulance at scene) was 6.42 min. The average arrest-to-first-shock interval was 23.77 min. Factors predicting survival included initial rhythm and arrest-to-first-shock interval. The survival rate of 1.6% is low by world standards. To improve the survival rates of people with out-of-hospital cardiac arrest, the arrest-to-call interval must be reduced and the frequency of bystander CPR assistance increased. Once these changes are in place, a beneficial effect from the use of pre-hospital defibrillation might be seen.     

Efficacy of bystander CPR: intervention by lay people and by health care professionals

BACKGROUND: Early cardiopulmonary resuscitation (CPR) by bystanders prior to the arrival of the rescue team has been shown to be associated with increased survival after out-of-hospital cardiac arrest. The aim of this survey was to evaluate the impact on survival of no bystander CPR, lay bystander CPR and professional bystander CPR. METHODS: Patients suffering an out-of-hospital cardiac arrest in Sweden between 1990 and 2002 who were given CPR and were not witnessed by the ambulance crew were included. RESULTS: In all, 29,711 patients were included, 36% of whom received bystander CPR prior to the arrival of the rescue team. Among the latter, 72% received CPR from lay people and 28% from professionals. Survival to 1 month was 2.2% among those who received no bystander CPR, 4.9% among those who received bystander CPR from lay people (p<0.0001) and 9.2% among those who received bystander CPR from professionals (p<0.0001 compared with bystander CPR by lay people). In a multivariate analysis, lay bystander CPR was associated with improved survival compared to no bystander CPR (OR: 2.04; 95% CI: 1.72-2.42), and professional bystander CPR was associated with improved survival compared to lay bystander CPR (OR: 1.37; 95% CI: 1.12-1.67). CONCLUSION: Among patients suffering an out-of-hospital cardiac arrest, bystander CPR by lay persons (excluding health care professionals) is associated with an increased chance of survival. Furthermore, there is a distinction between lay persons and health care providers; survival is higher when the latter perform bystander CPR. However, these results may not be explained by differences in the quality of CPR.     

Comparison of mechanical techniques of cardiopulmonary resuscitation: survival and neurologic outcome in dogs

Three currently available mechanical devices for cardiopulmonary resuscitation (CPR) were compared using a canine cardiac arrest model. Twenty-four-hour survival without neurologic deficit was the goal. A group of 30 large mongrel dogs was divided equally among Thumper CPR, simultaneous compression and ventilation (SCV) CPR, and vest CPR. Ventricular fibrillation was induced electrically, and after 3 minutes of no intervention, one of the three types of mechanical CPR was performed for 17 minutes. SCV CPR and vest CPR produced significantly greater aortic and right atrial systolic pressures than Thumper CPR (P less than .03). The SCV CPR technique also produced significantly higher aortic diastolic pressure and right atrial diastolic pressure than either of the other methods (P less than .03). However, coronary perfusion pressure was not different among the three mechanical methods. No differences in immediate resuscitation, 24-hour survival, or neurologic deficit scores at 24 hours were found. Neither SCV nor the vest techniques of CPR appear better for survival or neurologic outcome than standard cardiopulmonary resuscitation performed with the Thumper.     

Resuscitation Outcomes Consortium (ROC) PRIMED cardiac arrest trial methods part 2: rationale and methodology for "Analyze Later vs. Analyze Early" protocol

OBJECTIVE: The primary objective of the trial is to compare survival to hospital discharge with modified Rankin score (MRS) < or =3 between a strategy that prioritizes a specified period of CPR before rhythm analysis (Analyze Later) versus a strategy of minimal CPR followed by early rhythm analysis (Analyze Early) in patients with out-of-hospital cardiac arrest. METHODS: Design-Cluster randomized trial with cluster units defined by geographic region, or monitor/defibrillator machine. Population-Adults treated by emergency medical service (EMS) providers for non-traumatic out-of-hospital cardiac arrest not witnessed by EMS. Setting-EMS systems participating in the Resuscitation Outcomes Consortium and agreeing to cluster randomization to the Analyze Later versus Analyze Early intervention in a crossover fashion. Sample size-Based on a two-sided significance level of 0.05, a maximum of 13,239 evaluable patients will allow statistical power of 0.996 to detect a hypothesized improvement in the probability of survival to discharge with MRS < or =3 rate from 5.41% after Analyze Early to 7.45% after Analyze Later (2.04% absolute increase in primary outcome). CONCLUSION: If this trial demonstrates a significant improvement in survival with a strategy of Analyze Later, it is estimated that 4000 premature deaths from cardiac arrest would be averted annually in North America alone.     

Advanced life support drugs: do they really work?

Basic life support and rapid defibrillation for ventricular fibrillation or pulseless ventricular tachycardia are the only two interventions that have been shown unequivocally to improve survival after cardiac arrest. Several drugs are advocated to treat cardiac arrest, but despite very encouraging animal data, no drug has been reliably proven to increase survival to hospital discharge after cardiac arrest. This review focuses on recent experimental and clinical data concerning the use of vasopressin, amiodarone, magnesium, and fibrinolytics during advanced life support (ALS). Animal data indicate that, in comparison with epinephrine (adrenaline), vasopressin produces better vital organ blood flow during cardiopulmonary resuscitation (CPR). These apparent advantages have yet to be converted into improved survival in large-scale trials of cardiac arrest in humans. Data from two prospective, randomized trials suggest that amiodarone may improve short-term survival after out-of-hospital ventricular fibrillation cardiac arrest. On the basis of anecdotal data, magnesium is recommended therapy for torsades de pointes and for shock-resistant ventricular fibrillation associated with hypomagnesemia. In the past, CPR has been a contraindication to giving fibrinolytics, but several studies have demonstrated the relative safety of fibrinolysis during and after CPR. Fibrinolytics are likely to be beneficial when cardiac arrest is associated with plaque rupture and fresh coronary thrombus or massive pulmonary embolism. Fibrinolysis may also improve cerebral microcirculatory perfusion once a spontaneous circulation has been restored. A planned, prospective, randomized trial may help to define the role of fibrinolysis during out-of-hospital CPR.     

Pre-hospital treatment of acute poisonings in Oslo

Background

Cardiac arrest is the leading cause of mortality in Canada, and the overall survival rate for out-of-hospital cardiac arrest rarely exceeds 5%. Bystander cardiopulmonary resuscitation (CPR) has been shown to increase survival for cardiac arrest victims. However, bystander CPR rates remain low in Canada, rarely exceeding 15%, despite various attempts to improve them. Dispatch-assisted CPR instructions have the potential to improve rates of bystander CPR and many Canadian urban communities now offer instructions to callers reporting a victim in cardiac arrest. Dispatch-assisted CPR instructions are recommended by the International Guidelines on Emergency Cardiovascular Care, but their ability to improve cardiac arrest survival remains unclear.

Methods/Design

The overall goal of this study is to better understand the factors leading to successful dispatch-assisted CPR instructions and to ultimately save the lives of more cardiac arrest patients. The study will utilize a before-after, prospective cohort design to specifically: 1) Determine the ability of 9-1-1 dispatchers to correctly diagnose cardiac arrest; 2) Quantify the frequency and impact of perceived agonal breathing on cardiac arrest diagnosis; 3) Measure the frequency with which dispatch-assisted CPR instructions can be successfully completed; and 4) Measure the impact of dispatch-assisted CPR instructions on bystander CPR and survival rates. The study will be conducted in 19 urban communities in Ontario, Canada. All 9-1-1 calls occurring in the study communities reporting out-of-hospital cardiac arrest in victims 16 years of age or older for which resuscitation was attempted will be eligible. Information will be obtained from 9-1-1 call recordings, paramedic patient care reports, base hospital records, fire medical records and hospital medical records. Victim, caller and system characteristics will be measured in the study communities before the introduction of dispatch-assisted CPR instructions (before group), during the introduction (run-in phase), and following the introduction (after group).

Discussion

The study will obtain information essential to the development of clinical trials that will test a variety of educational approaches and delivery methods for telephone cardiopulmonary resuscitation instructions. This will be the first study in the world to clearly quantify the impact of dispatch-assisted CPR instructions on survival to hospital discharge for out-of-hospital cardiac arrest victims.

Trial Registration

ClinicalTrials.gov NCT00664443     

Survival in cancer patients after out-of-hospital cardiac arrest

Background  

The survival of cancer patients who undergo cardiopulmonary resuscitation (CPR) after in-hospital cardiac arrest is poor. The survival of cancer patients who undergo CPR after out-of-hospital cardiac arrest is unknown. We sought to determine survival rates in such patients and to identify phrases in patient charts that might have prompted end-of-life discussions.