Efficacy of chest compression-only BLS CPR in the presence of an occluded airway

Chest compressions versus ventilation plus chest compressions in a pediatric asphyxial cardiac arrest animal model

OBJECTIVE

To compare the ventilation achieved with chest compressions (CC) or ventilation plus compressions (VC) in a pediatric animal model of cardiac arrest.

DESIGN

Randomized experimental study.

SETTING

Experimental department of a University Hospital.

METHODS

Twelve infant pigs with asphyxial cardiac arrest. Sequential 3-min periods of VC and CC were performed for a total duration of 9 min. Tidal volume (TV), end-tidal CO(2) (EtCO(2)), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary arterial pressure (mPAP), and peripheral, cerebral, and renal saturations were recorded and arterial and venous blood gases were analyzed.

RESULTS

VC achieved a TV similar to the preset parameters on the ventilator, whilst the TV in CC was very low (P < 0.001). EtCO(2) with VC was significantly higher than with CC (14.0 vs. 3.9 mmHg, P < 0.05). Arterial pH was higher with VC than with CC (6.99 vs. 6.90 mmHg, P < 0.05). Arterial PCO(2) was lower with VC than with CC (62.1 vs. 97.0 mmHg, P < 0.05). There were no significant differences in the MAP; CVP; mPAP; peripheral, renal, and cerebral saturations; or lactate concentrations between the two techniques.

CONCLUSIONS

VC achieves better ventilation than CC during cardiopulmonary resuscitation and has no negative effect on the hemodynamic situation.

Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation

BACKGROUND

Quality cardiopulmonary resuscitation contributes to cardiac arrest survival. The proportion of time in which chest compressions are performed in each minute of cardiopulmonary resuscitation is an important modifiable aspect of quality cardiopulmonary resuscitation. We sought to estimate the effect of an increasing proportion of time spent performing chest compressions during cardiac arrest on survival to hospital discharge in patients with out-of-hospital ventricular fibrillation or pulseless ventricular tachycardia.

METHODS AND RESULTS

This is a prospective observational cohort study of adult patients from the Resuscitation Outcomes Consortium Cardiac Arrest Epistry with confirmed ventricular fibrillation or ventricular tachycardia, no defibrillation before emergency medical services arrival, electronically recorded cardiopulmonary resuscitation before the first shock, and a confirmed outcome. Patients were followed up to discharge from the hospital or death. Of the 506 cases, the mean age was 64 years, 80% were male, 71% were witnessed by a bystander, 51% received bystander cardiopulmonary resuscitation, 34% occurred in a public location, and 23% survived. After adjustment for age, gender, location, bystander cardiopulmonary resuscitation, bystander witness status, and response time, the odds ratios of surviving to hospital discharge in the 2 highest categories of chest compression fraction compared with the reference category were 3.01 (95% confidence interval 1.37 to 6.58) and 2.33 (95% confidence interval 0.96 to 5.63). The estimated adjusted linear effect on odds ratio of survival for a 10% change in chest compression fraction was 1.11 (95% confidence interval 1.01 to 1.21).

CONCLUSIONS

An increased chest compression fraction is independently predictive of better survival in patients who experience a prehospital ventricular fibrillation/tachycardia cardiac arrest.

Basic life support with four different compression/ventilation ratios in a pig model: the need for ventilation

BACKGROUND

During cardiac arrest the paramount goal of basic life support (BLS) is the oxygenation of vital organs. Current recommendations are to combine chest compressions with ventilation in a fixed ratio of 30:2; however the optimum compression/ventilation ratio is still debatable. In our study we compared four different compression/ventilation ratios and documented their effects on the return of spontaneous circulation (ROSC), gas exchange, cerebral tissue oxygenation and haemodynamics in a pig model.

METHODS

Study was performed on 32 pigs under general anaesthesia with endotracheal intubation. Arterial and central venous lines were inserted. For continuous cerebral tissue oxygenation a Licox PtiO(2) probe was implanted. After 3 min of cardiac arrest (ventricular fibrillation) animals were randomized to a compression/ventilation-ratio 30:2, 100:5, 100:2 or compressions-only. Subsequently 10 min BLS, Advanced Life Support (ALS) was performed (100%O(2), 3 defibrillations, 1mg adrenaline i.v.). Data were analyzed with 2-factorial ANOVA.

RESULTS

ROSC was achieved in 4/8 (30:2), 5/8 (100:5), 2/8 (100:2) and 0/8 (compr-only) pigs. During BLS, PaCO(2) increased to 55 mm Hg (30:2), 68 mm Hg (100:5; p=0.0001), 66 mm Hg (100:2; p=0.002) and 72 mm Hg (compr-only; p<0.0001). PaO(2) decreased to 58 mmg (30:2), 40 mm Hg (100:5; p=0.15), 43 mm Hg (100:2; p=0.04) and 26 mm Hg (compr-only; p<0.0001). PtiO(2) baseline values were 12.7, 12.0, 11.1 and 10.0 mm Hg and decreased to 8.1 mm Hg (30:2), 4.1 mm Hg (100:5; p=0.08), 4.3 mm Hg (100:2; p=0.04), and 4.5 mm Hg (compr-only; p=0.69).

CONCLUSIONS

During BLS, a compression/ventilation-ratio of 100:5 seems to be equivalent to 30:2, while ratios of 100:2 or compressions-only detoriate peripheral arterial oxygenation and reduce the chance for ROSC.

Optimizing chest compressions during delivery-room resuscitation

There is a paucity of data to support the recommendations for cardiac compressions for the newly born. Techniques, compression to ventilation ratios, hand placement, and depth of compression guidelines are generally based on expert consensus, physiologic plausibility, and data from pediatric and adult models.

Immediate post-shock chest compressions improve outcome from prolonged ventricular fibrillation

AIM

This study was designed to test the hypothesis that immediate post-shock chest compressions improve outcome from prolonged ventricular fibrillation (VF) compared with typical "hands off" period (i.e., delayed post-shock compressions) associated with AED use.

MATERIALS AND METHODS

After 7.5 min of untreated VF, 36 domestic swine (26+/-1 kg) were treated with 200 J biphasic shocks and randomly assigned to: (1) 1 min of immediate post-shock chest compressions or (2) simulated pre-hospital automated external defibrillator (AED) care with delays in post-shock chest compressions. Return of spontaneous circulation (ROSC) occurred in 7/18 immediate chest compressions animals within 2 min of the first shock versus 0/18 AED animals (P<0.01). Ten of 18 immediate chest compressions animals attained ROSC compared with 3/18 AED animals (P<0.05). Nine of 18 immediate chest compressions swine were alive at 24 and 48 h compared with 3/18 AED swine (P<0.05). All 48-h survivors had good neurologic outcomes. Among the 21 animals that defibrillated with the first shock, ROSC was attained in 7/10 immediate chest compressions animals within 2 min of the first shock compared with 0/11 AED animals (P=0.001), and 48-h survival was attained in 8/10 versus 3/11, respectively (P<0.05).

CONCLUSIONS

Immediate post-shock chest compressions can substantially improve outcome from prolonged VF compared with simulated pre-hospital AED care.

Improved neurological outcome with continuous chest compressions compared with 30:2 compressions-to-ventilations cardiopulmonary resuscitation in a realistic swine model of out-of-hospital cardiac arrest

BACKGROUND

The 2005 Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care changed the previous ventilations-to-chest-compression algorithm for bystander cardiopulmonary resuscitation (CPR) from 2 ventilations before each 15 chest compressions (2:15 CPR) to 30 chest compressions before 2 ventilations (30:2 CPR). It was acknowledged in the guidelines that the change was based on a consensus rather than clear evidence. This study was designed to compare 24-hour neurologically normal survival between the initial applications of continuous chest compressions without assisted ventilations with 30:2 CPR in a swine model of witnessed out-of-hospital ventricular fibrillation cardiac arrest.

METHODS AND RESULTS

Sixty-four animals underwent 12 minutes of ventricular fibrillation before defibrillation attempts. They were divided into 4 groups, each with increasing durations (3, 4, 5, and 6 minutes, respectively) of untreated ventricular fibrillation before the initiation of bystander resuscitation consisting of either continuous chest compression or 30:2 CPR. After the various untreated ventricular durations plus bystander resuscitation durations, all animals were given the first defibrillation attempt 12 minutes after the induction of ventricular fibrillation, followed by the 2005 guideline-recommended advanced cardiac life support. Neurologically normal survival at 24 hours after resuscitation was observed in 23 of 33 (70%) of the animals in the continuous chest compression groups but in only 13 of 31 (42%) of the 30:2 CPR groups (P=0.025).

CONCLUSIONS

In a realistic model of out-of-hospital ventricular fibrillation cardiac arrest, initial bystander administration of continuous chest compressions without assisted ventilations resulted in significantly better 24-hour postresuscitation neurologically normal survival than did the initial bystander administration of 2005 guideline-recommended 30:2 CPR.

Recent advances and controversies in adult cardiopulmonary resuscitation

Since its introduction more than four and half decades ago, the science of cardiopulmonary resuscitation has been enriched with a significant amount of scientific evidence. This in turn has led to the birth of new evidence based guidelines for resuscitation published by the European Resuscitation Council and the American Heart Association in late 2005. This article aims to review the recent advances and controversies in the science of resuscitation.

The Save Hearts in Arizona Registry and Education (SHARE) program: Who is performing CPR and where are they doing it?

BACKGROUND

Bystander cardiopulmonary resuscitation (CPR) decreases mortality from out-of-hospital cardiac arrest significantly. Accordingly, layperson CPR is an integral component in the chain of survival for out-of-hospital cardiac arrest victims. The near statewide incidence and location of layperson CPR is unknown.

OBJECTIVE

To determine true incidence and location of layperson CPR in the State of Arizona.

METHODS

The Save Hearts in Arizona Registry and Education (SHARE) program reviewed EMS first care reports submitted voluntarily by 30 municipal fire departments responsible for approximately 67% of Arizona's population. In addition to standard Utstein style data, information regarding the performance of bystander CPR, the vocation and medical training of the bystander and the location of the arrest were documented.

RESULTS

The total number of out-of-hospital adult arrests of presumed cardiac etiology reported statewide was 1097. Cardiac arrests occurred in private residences in 67%, extended care or medical facilities in 18%, and public locations in 15%. Bystander CPR was performed in 37% of all arrests, 24% of residential arrests, 76% of extended care or medical facility arrests, and 52% of public arrests. Bystander CPR provided an odds ratio of 2.2 for survival [95% CI 1.2-4.1]. Excluding cardiac arrests which occurred in the presence of bystanders with formal CPR training as part of their job description, layperson CPR was performed in 218 of 857 (25%) of cases.

CONCLUSIONS

The near statewide incidence of layperson CPR is extremely low. This low rate of bystander CPR is likely to contribute to the low overall survival rates from cardiac arrest. Public health officials should re-evaluate current models of public education on CPR.

Sustained abdominal compression during CPR raises coronary perfusion pressures as much as vasopressor drugs

OBJECTIVES

This study investigated sustained abdominal compression as a means to improve coronary perfusion pressure (CPP) during cardiopulmonary resuscitation (CPR) and compared the resulting CPP augmentation with that achieved using vasopressor drugs.

METHOD

During electrically induced ventricular fibrillation in anesthetized, 30kg juvenile pigs, Thumper CPR was supplemented at intervals either by constant abdominal compression at 100-500mmHg using an inflated contoured cuff or by the administration of vasopressor drugs (epinephrine, vasopressin, or glibenclamide). CPP before and after cuff inflation or drug administration was the end point.

RESULTS

Sustained abdominal compression at >200mmHg increases CPP during VF and otherwise standard CPR by 8-18mmHg. The effect persists over practical ranges of chest compression force and duty cycle and is similar to that achieved with vasopressor drugs. Constant abdominal compression also augments CPP after prior administration of epinephrine or vasopressin.

CONCLUSIONS

During CPR noninvasive abdominal compression with the inflatable contoured cuff rapidly elevates the CPP, sustains the elevated CPP as long as the device is inflated, and is immediately and controllably reversible upon device deflation. Physical control of peripheral vascular resistance during CPR by abdominal compression has some advantages over pharmacological manipulation and deserves serious reconsideration, now that the limitations of pressor drugs during CPR have become better understood, including post-resuscitation myocardial depression and the need for intravenous access.

Compression-only cardiopulmonary resuscitation for bystanders and first responders

PURPOSE OF REVIEW

The current resuscitation guidelines consider ventilation and chest compression essential components of resuscitation and therefore only one methodology, standard cardiopulmonary resuscitation, is explicitly recommended for the treatment of both respiratory and cardiac arrests. Pathophysiological and experimental observations argue that this generalization results in suboptimal treatment for victims of cardiac arrest.

RECENT FINDINGS

For more than a decade animal studies have demonstrated that assisted ventilation is not essential during the initial treatment of a fibrillatory arrest; but only in the last year have these results been confirmed in humans. These new observations come from a handful of systems utilizing cardiocerebral resuscitation in their prehospital resuscitation of adult victims of presumed cardiac arrest. They have all demonstrated a dramatic increase in survival. Recent data also indicate that survival is significantly increased when laypersons perform chest-compression-only cardiopulmonary resuscitation.

SUMMARY

The current resuscitation guidelines regarding the prehospital treatment of victims of adult cardiac arrest should be modified to explicitly permit the use of continuous-chest-compression cardiopulmonary resuscitation.

Resuscitation outcomes comparing year 2000 with year 2005 ALS guidelines in a pig model of cardiac arrest

BACKGROUND

Ventricular fibrillation remains the leading cause of death in western societies. International organizations publish guidelines to follow in case of cardiac arrest. The aim of the present study is to assess whether the newly published guidelines record similar resuscitation success with the 2000 Advanced Life Support Guidelines on Resuscitation in a swine model of cardiac arrest.

METHODS AND RESULTS

Nineteen landrace/large white pigs were used. Ventricular fibrillation was induced with the use of a transvenous pacing wire inserted into the right ventricle. The animals were randomized into two groups. In Group A, 10 animals were resuscitated using the 2000 guidelines, whereas in Group B, 9 animals were resuscitated using the 2005 guidelines. Both algorithms recorded similar successful resuscitation rates, as 60% of the animals in Group A and 44.5% in Group B were successfully resuscitated. However, animals in Group A restored a rhythm, compatible with a pulse, quicker than those in Group B (p=0.002). Coronary perfusion pressure (CPP) was not adversely affected by three defibrillation attempts in Group A.

CONCLUSIONS

Both algorithms' resulted in comparable resuscitation success, however, guidelines 2000 resulted in faster resuscitation times. These preliminary results merit further investigation.

Basic Life Support Ventilation in Mountain Rescue

Cardiopulmonary resuscitation in the mountains usually has to be performed under difficult and hostile circumstances and sometimes for extended periods of time. Therefore, mountain rescuers should have the ability and the appropriate equipment to perform prolonged, efficient, and safe ventilation. Members of the International Commission for Mountain Emergency Medicine (ICAR MEDCOM) discussed the results of a literature review, focusing on the advantages and disadvantages of common ventilation techniques in basic life support and their training methods with specific respect to use in mountain rescue, and recommendations were proposed. Bystanders fear the potential risk of infection and lack the willingness to perform mouth-to-mouth ventilation, though the risk of infection is low. Mouth-to-mouth ventilation remains the standard technique for bystander ventilation and, in the absence of a barrier device, bystanders should not hesitate to ventilate a patient by this technique. For mountain rescue teams, we encourage the use of a barrier device for artificial ventilation. Mouth-to-mask ventilation devices are most likely to fulfill the requirements of being safe, simple, and efficient in the hands of a basic-trained rescuer. The use of a mouth-to-mask ventilation device is recommended for out-of-hospital ventilation in the mountains and should be part of the mountain rescuer's standard equipment. Bag-valve-mask ventilation is efficient, if performed by well-trained rescuers, but it leads to a low ventilation quality in the hands of a less experienced rescuer. It should be emphasized that regular training every 6 to 12 months is necessary to perform proper ventilation.

Comparison of ventilation and chest compression performance by bystanders using the Impact Model 730 ventilator and a conventional bag valve with mask in a model of adult cardiopulmonary arrest

"Bystanders" or lay persons are typically the first caregivers to attend to a victim of out-of-hospital cardiopulmonary arrest. Astronaut crew medical officers (CMO) play a similar role to bystanders aboard the International Space Station (ISS). Studies have demonstrated the importance of bystander cardiopulmonary resuscitation (BCPR) for patient survival before the arrival of emergency medical care. Recent apprehension from bystanders about the threat of contracting communicable diseases during BCPR, however, has led to the consideration of other ventilation systems such as the bag-valve mask (BVM) and automatic transport ventilators (ATV). BVM use is called for during CPR aboard the ISS. This study evaluated the ventilation and compression performance of 40 basic CPR-trained bystanders using either a BVM (adult-sized self-inflating bag with face mask) or an ATV (Model 730 ventilator (M730), Impact Instrumentation, Inc., West Caldwell, NJ). Each two-bystander team gave BCPR to a simulated cardiopulmonary arrest victim using the 2-breath/15-compression cycle for 4 min and then switched roles for another 4-min interval. Compared to BVM use, the M730 led to significantly (p<0.05) lower number of breaths, smaller tidal volumes, airway flows, airway pressures, volume of gas entering the stomach per breath and chest compressions for the 4-min period. The M730 also enabled a bystander to meet the recommendation of 4-breath and compression cycles per minute as per Guidelines 2000. Lastly, ease-of-use scores were significantly higher for the M730 compared to the BVM. Overall, the data suggest that the M730 improves the quality of performance for a bystander performing BCPR.

Rescuer fatigue: standard versus continuous chest-compression cardiopulmonary resuscitation

OBJECTIVES

Continuous chest-compression cardiopulmonary resuscitation (CCC-CPR) has been advocated as an alternative to standard CPR (STD-CPR). Studies have shown that CCC-CPR delivers substantially more chest compressions per minute and is easier to remember and perform than STD-CPR. One concern regarding CCC-CPR is that the rescuer may fatigue and be unable to maintain adequate compression rate or depth throughout an average emergency medical services response time. The specific aim of this study was to compare the effects of fatigue on the performance of CCC-CPR and STD-CPR on a manikin model.

METHODS

This was a prospective, randomized crossover study involving 53 medical students performing CCC-CPR and STD-CPR on a manikin model. Students were randomized to their initial CPR group and then performed the other type of CPR after a period of at least two days. Students were evaluated on their performance of 9 minutes of CPR for each method. The primary endpoint was the number of adequate chest compressions (at least 38 mm of compression depth) delivered per minute during each of the 9 minutes. The secondary endpoints were total compressions, compression rate, and the number of breaks taken for rest. The students' performance was evaluated on the basis of Skillreporter Resusci Anne (Laerdal, Wappingers Falls, NY) recordings. Primary and secondary endpoints were analyzed by using the generalized linear mixed model for counting data.

RESULTS

In the first 2 minutes, participants delivered significantly more adequate compressions per minute with CCC-CPR than STD-CPR, (47 vs. 32, p = 0.004 in the 1st minute and 39 vs. 29, p = 0.04 in the 2nd minute). For minutes 3 through 9, the differences in number of adequate compressions between groups were not significant. Evaluating the 9 minutes of CPR as a whole, there were significantly more adequate compressions in CCC-CPR vs. STD-CPR (p = 0.0003). Although the number of adequate compressions per minute declined over time in both groups, the rate of decline was significantly greater in CCC-CPR compared with STD-CPR (p = 0.0003). The mean number of total compressions delivered in the first minute was significantly greater with CCC-CPR than STD-CPR (105 per minute vs. 58 per minute, p < 0.001) and did not change over 9 minutes in either group. There were no differences in compression rates or number of breaks between groups.

CONCLUSIONS

CCC-CPR resulted in more adequate compressions per minute than STD-CPR for the first 2 minutes of CPR. However, the difference diminished after 3 minutes, presumably as a result of greater rescuer fatigue with CCC-CPR. Overall, CCC-CPR resulted in more total compressions per minute than STD-CPR during the entire 9 minutes of resuscitation.

Single rescuer cardiopulmonary resuscitation: Can anyone perform to the guidelines 2000 recommendations?

BACKGROUND

The Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care recommend that for adult cardiac arrest the single rescuer performs "two quick breaths followed by 15 chest compressions." This cycle is continued until additional help arrives. Previous studies have shown that lay persons and medical students take 16 +/- 1 and 14 +/- 1 s, respectively, to perform these "two quick breaths." The purpose of this study was to determine the time required for trained professional paramedic firefighters to deliver these two breaths and the effects that any increase in the time it takes to perform rescue breathing would have on the number of chest compressions delivered during single rescuer BLS CPR. We hypothesized that trained professional rescuers would also take substantially longer then the Guidelines recommendation for delivering the two rescue breaths before every 15 compressions during simulated single rescuer BLS CPR.

METHODS

Twenty-four paramedic firefighters currently certified to perform BLS CPR were evaluated for their ability to deliver the two recommended breaths within 4 s according to the AHA 2000 CPR Guidelines. Alternatively, a simplified technique of continuous chest compression BLS CPR (CCC) was also taught and compared with standard BLS CPR (STD). Without revealing the purpose of the study the paramedics were asked to perform single rescuer BLS CPR on a recording Resusci Anne while being videotaped.

RESULTS

The mean length of time needed to provide the "two quick breaths" during STD-CPR was 10 +/- 1 s. The mean number of chest compressions/min delivered with AHA BLS CPR was only 44 +/- 2. Continuous chest compression CPR resulted in 88 +/- 5 compressions delivered per minute (STD versus CCC; p < 0.0001).

CONCLUSIONS

Trained professional emergency rescue workers perform rescue breathing somewhat faster than lay rescuers or medical students, but still require two and one half times longer than recommended. The time required to perform these breaths significantly decreases the number of chest compressions delivered per minute. This may affect outcome as experimental studies have shown that more than 80 compressions delivered per minute are necessary for survival from prolonged cardiac arrest.

The need for head rotation and abdominal compressions during bystander cardiopulmonary resuscitation

The current AHA-ECC guidelines for basic life support focus on the provision of good chest compressions with minimal interruptions for patients with presumed out-of-hospital cardiac arrest. Moreover, international consensus guidelines now support the use of chest compression-only cardiopulmonary resuscitation (CPR) instructions for dispatcher-assisted CPR given over the phone to untrained bystanders. However, evidence that strongly challenge these recommendations have been overlooked. A review of this evidence argues for the need for head rotation (a hands-free method of airway control) and abdominal compressions during bystander CPR.

The International Liaison Committee on Resuscitation (ILCOR) consensus on science with treatment recommendations for pediatric and neonatal patients: pediatric basic and advanced life support

This publication contains the pediatric and neonatal sections of the 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations (COSTR). The consensus process that produced this document was sponsored by the International Liaison Committee on Resuscitation (ILCOR). ILCOR was formed in 1993 and consists of representatives of resuscitation councils from all over the world. Its mission is to identify and review international science and knowledge relevant to cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) and to generate consensus on treatment recommendations. ECC includes all responses necessary to treat life-threatening cardiovascular and respiratory events. The COSTR document presents international consensus statements on the science of resuscitation. ILCOR member organizations are each publishing resuscitation guidelines that are consistent with the science in this consensus document, but they also take into consideration geographic, economic, and system differences in practice and the regional availability of medical devices and drugs. The American Heart Association (AHA) pediatric and the American Academy of Pediatrics/AHA neonatal sections of the resuscitation guidelines are reprinted in this issue of Pediatrics (see pages e978-e988). The 2005 evidence evaluation process began shortly after publication of the 2000 International Guidelines for CPR and ECC. The process included topic identification, expert topic review, discussion and debate at 6 international meetings, further review, and debate within ILCOR member organizations and ultimate approval by the member organizations, an Editorial Board, and peer reviewers. The complete COSTR document was published simultaneously in Circulation (International Liaison Committee on Resuscitation. 2005 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Circulation. 2005;112(suppl):73-90) and Resuscitation (International Liaison Committee on Resuscitation. 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Resuscitation. 2005;67:271-291). Readers are encouraged to review the 2005 COSTR document in its entirety. It can be accessed through the CPR and ECC link at the AHA Web site: www.americanheart.org. The complete publication represents the largest evaluation of resuscitation literature ever published and contains electronic links to more detailed information about the international collaborative process. To organize the evidence evaluation, ILCOR representatives established 6 task forces: basic life support, advanced life support, acute coronary syndromes, pediatric life support, neonatal life support, and an interdisciplinary task force to consider overlapping topics such as educational issues. The AHA established additional task forces on stroke and, in collaboration with the American Red Cross, a task force on first aid. Each task force identified topics requiring evaluation and appointed international experts to review them. A detailed worksheet template was created to help the experts document their literature review, evaluate studies, determine levels of evidence, develop treatment recommendations, and disclose conflicts of interest. Two evidence evaluation experts reviewed all worksheets and assisted the worksheet reviewers to ensure that the worksheets met a consistently high standard. A total of 281 experts completed 403 worksheets on 275 topics, reviewing more than 22000 published studies. In December 2004 the evidence review and summary portions of the evidence evaluation worksheets, with worksheet author conflict of interest statements, were posted on the Internet at www.C2005.org, where readers can continue to access them. Journal advertisements and e-mails invited public comment. Two hundred forty-nine worksheet authors (141 from the United States and 108 from 17 other countries) and additional invited experts and reviewers attended the 2005 International Consensus Conference for presentation, discussion, and debate of the evidence. All 380 participants at the conference received electronic copies of the worksheets. Internet access was available to all conference participants during the conference to facilitate real-time verification of the literature. Expert reviewers presented topics in plenary, concurrent, and poster conference sessions with strict adherence to a novel and rigorous conflict of interest process. Presenters and participants then debated the evidence, conclusions, and draft summary statements. Wording of science statements and treatment recommendations was refined after further review by ILCOR member organizations and the international editorial board. This format ensured that the final document represented a truly international consensus process. The COSTR manuscript was ultimately approved by all ILCOR member organizations and by an international editorial board. The AHA Science Advisory and Coordinating Committee and the editor of Circulation obtained peer reviews of this document before it was accepted for publication. The most important changes in recommendations for pediatric resuscitation since the last ILCOR review in 2000 include: Increased emphasis on performing high quality CPR: "Push hard, push fast, minimize interruptions of chest compression; allow full chest recoil, and don't provide excessive ventilation" Recommended chest compression-ventilation ratio: For lone rescuers with victims of all ages: 30:2 For health care providers performing 2-rescuer CPR for infants and children: 15:2 (except 3:1 for neonates) Either a 2- or 1-hand technique is acceptable for chest compressions in children Use of 1 shock followed by immediate CPR is recommended for each defibrillation attempt, instead of 3 stacked shocks Biphasic shocks with an automated external defibrillator (AED) are acceptable for children 1 year of age. Attenuated shocks using child cables or activation of a key or switch are recommended in children <8 years old. Routine use of high-dose intravenous (IV) epinephrine is no longer recommended. Intravascular (IV and intraosseous) route of drug administration is preferred to the endotracheal route. Cuffed endotracheal tubes can be used in infants and children provided correct tube size and cuff inflation pressure are used. Exhaled CO2 detection is recommended for confirmation of endotracheal tube placement. Consider induced hypothermia for 12 to 24 hours in patients who remain comatose following resuscitation. Some of the most important changes in recommendations for neonatal resuscitation since the last ILCOR review in 2000 include less emphasis on using 100% oxygen when initiating resuscitation, de-emphasis of the need for routine intrapartum oropharyngeal and nasopharyngeal suctioning for infants born to mothers with meconium staining of amniotic fluid, proven value of occlusive wrapping of very low birth weight infants <28 weeks' gestation to reduce heat loss, preference for the IV versus the endotracheal route for epinephrine, and an increased emphasis on parental autonomy at the threshold of viability. The scientific evidence supporting these recommendations is summarized in the neonatal document (see pages e978-e988).

2005 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) of pediatric and neonatal patients: pediatric basic life support

This publication presents the 2005 American Heart Association (AHA) guidelines for cardiopulmonary resuscitation (CPR) and emergency cardiovascular care (ECC) of the pediatric patient and the 2005 American Academy of Pediatrics/AHA guidelines for CPR and ECC of the neonate. The guidelines are based on the evidence evaluation from the 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations, hosted by the American Heart Association in Dallas, Texas, January 23-30, 2005. The "2005 AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care" contain recommendations designed to improve survival from sudden cardiac arrest and acute life-threatening cardiopulmonary problems. The evidence evaluation process that was the basis for these guidelines was accomplished in collaboration with the International Liaison Committee on Resuscitation (ILCOR). The ILCOR process is described in more detail in the "International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations." The recommendations in the "2005 AHA Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care" confirm the safety and effectiveness of many approaches, acknowledge that other approaches may not be optimal, and recommend new treatments that have undergone evidence evaluation. These new recommendations do not imply that care involving the use of earlier guidelines is unsafe. In addition, it is important to note that these guidelines will not apply to all rescuers and all victims in all situations. The leader of a resuscitation attempt may need to adapt application of the guidelines to unique circumstances. The following are the major pediatric advanced life support changes in the 2005 guidelines: There is further caution about the use of endotracheal tubes. Laryngeal mask airways are acceptable when used by experienced providers. Cuffed endotracheal tubes may be used in infants (except newborns) and children in in-hospital settings provided that cuff inflation pressure is kept <20 cm H2O. Confirmation of tube placement requires clinical assessment and assessment of exhaled carbon dioxide (CO2); esophageal detector devices may be considered for use in children weighing >20 kg who have a perfusing rhythm. Correct placement must be verified when the tube is inserted, during transport, and whenever the patient is moved. During CPR with an advanced airway in place, rescuers will no longer perform "cycles" of CPR. Instead, the rescuer performing chest compressions will perform them continuously at a rate of 100/minute without pauses for ventilation. The rescuer providing ventilation will deliver 8 to 10 breaths per minute (1 breath approximately every 6-8 seconds). Timing of 1 shock, CPR, and drug administration during pulseless arrest has changed and now is identical to that for advanced cardiac life support. Routine use of high-dose epinephrine is not recommended. Lidocaine is de-emphasized, but it can be used for treatment of ventricular fibrillation/pulseless ventricular tachycardia if amiodarone is not available. Induced hypothermia (32-34 degrees C for 12-24 hours) may be considered if the child remains comatose after resuscitation. Indications for the use of inodilators are mentioned in the postresuscitation section. Termination of resuscitative efforts is discussed. It is noted that intact survival has been reported following prolonged resuscitation and absence of spontaneous circulation despite 2 doses of epinephrine. The following are the major neonatal resuscitation changes in the 2005 guidelines: Supplementary oxygen is recommended whenever positive-pressure ventilation is indicated for resuscitation; free-flow oxygen should be administered to infants who are breathing but have central cyanosis. Although the standard approach to resuscitation is to use 100% oxygen, it is reasonable to begin resuscitation with an oxygen concentration of less than 100% or to start with no supplementary oxygen (ie, start with room air). If the clinician begins resuscitation with room air, it is recommended that supplementary oxygen be available to use if there is no appreciable improvement within 90 seconds after birth. In situations where supplementary oxygen is not readily available, positive-pressure ventilation should be administered with room air. Current recommendations no longer advise routine intrapartum oropharyngeal and nasopharyngeal suctioning for infants born to mothers with meconium staining of amniotic fluid. Endotracheal suctioning for infants who are not vigorous should be performed immediately after birth. A self-inflating bag, a flow-inflating bag, or a T-piece (a valved mechanical device designed to regulate pressure and limit flow) can be used to ventilate a newborn. An increase in heart rate is the primary sign of improved ventilation during resuscitation. Exhaled CO2 detection is the recommended primary technique to confirm correct endotracheal tube placement when a prompt increase in heart rate does not occur after intubation. The recommended intravenous (IV) epinephrine dose is 0.01 to 0.03 mg/kg per dose. Higher IV doses are not recommended, and IV administration is the preferred route. Although access is being obtained, administration of a higher dose (up to 0.1 mg/kg) through the endotracheal tube may be considered. It is possible to identify conditions associated with high mortality and poor outcome in which withholding resuscitative efforts may be considered reasonable, particularly when there has been the opportunity for parental agreement. The following guidelines must be interpreted according to current regional outcomes: When gestation, birth weight, or congenital anomalies are associated with almost certain early death and when unacceptably high morbidity is likely among the rare survivors, resuscitation is not indicated. Examples are provided in the guidelines. In conditions associated with a high rate of survival and acceptable morbidity, resuscitation is nearly always indicated. In conditions associated with uncertain prognosis in which survival is borderline, the morbidity rate is relatively high, and the anticipated burden to the child is high, parental desires concerning initiation of resuscitation should be supported. Infants without signs of life (no heartbeat and no respiratory effort) after 10 minutes of resuscitation show either a high mortality rate or severe neurodevelopmental disability. After 10 minutes of continuous and adequate resuscitative efforts, discontinuation of resuscitation may be justified if there are no signs of life.

Insight into the New Changes in European Resuscitation Council Guidelines for Adult Resuscitation (2005)

It is five years now since the last European resuscitation guidelines were published(1). The science of resuscitation has been enriched with further significant scientific evidence that has led to new evidence-based guidelines. These guidelines were released in November 2005 and published in the international Journal of Resuscitation, November 2005(2).

What is the optimal chest compression-ventilation ratio?

PURPOSE OF REVIEW

Despite a more widespread knowledge of basic cardiopulmonary resuscitation maneuvers in the community, the survival rate for patients with cardiac arrest has remained essentially unchanged in the past 30 years. Over the past few decades, many different compression-ventilation ratios have been studied in terms of best coronary and cerebral oxygen delivery, restoration of spontaneous circulation, and neurologic outcome. This article summarizes the recent evidence presented at the International Consensus on Resuscitation Science in January 2005.

RECENT FINDINGS

Recent data from animal and mathematical models suggest a move to a higher compression-ventilation ratio to maximize coronary and cerebral oxygen delivery during cardiac arrest and long-term neurologic outcome. Prospective randomized human data on alternative compression-ventilation ratios are missing and new evidence seems to indicate the inadequacy of both lay and professional rescuers in providing chest compression and ventilating the victim in cardiac arrest. Finally, observational and animal studies highlight the hidden danger of inadvertent hyperventilation during advanced cardiac life support as a reduction of both coronary and perfusion pressure secondary to increased intrathoracic pressure and decreased venous return.

SUMMARY

The optimal compression-ventilation ratio is still unknown and the best tradeoff between oxygenation and organ perfusion during cardiopulmonary resuscitation is probably different for each patient and scenario. A discrepancy between what is recommended by the current guidelines and the 'real world' of cardiopulmonary resuscitation has resulted in a near flat survival rate from cardiac arrest in the past few years.

Chest compression rates during cardiopulmonary resuscitation are suboptimal: a prospective study during in-hospital cardiac arrest

BACKGROUND

Recent data highlight a vital link between well-performed cardiopulmonary resuscitation (CPR) and survival after cardiac arrest; however, the quality of CPR as actually performed by trained healthcare providers is largely unknown. We sought to measure in-hospital chest compression rates and to determine compliance with published international guidelines.

METHODS AND RESULTS

We developed and validated a handheld recording device to measure chest compression rate as a surrogate for CPR quality. A prospective observational study of adult cardiac arrests was performed at 3 hospitals from April 2002 to October 2003. Resuscitations were witnessed by trained observers using a customized personal digital assistant programmed to store the exact time of each chest compression, allowing offline calculation of compression rates at serial time points. In 97 arrests, data from 813 minutes during which chest compressions were delivered were analyzed in 30-second time segments. In 36.9% of the total number of segments, compression rates were <80 compressions per minute (cpm), and 21.7% had rates <70 cpm. Higher chest compression rates were significantly correlated with initial return of spontaneous circulation (mean chest compression rates for initial survivors and nonsurvivors, 90+/-17 and 79+/-18 cpm, respectively; P=0.0033).

CONCLUSIONS

In-hospital chest compression rates were below published resuscitation recommendations, and suboptimal compression rates in our study correlated with poor return of spontaneous circulation. CPR quality is likely a critical determinant of survival after cardiac arrest, suggesting the need for routine measurement, monitoring, and feedback systems during actual resuscitation.

A comparison of CPR delivery with various compression-to-ventilation ratios during two-rescuer CPR

BACKGROUND

The number of chest compressions required for optimal generation of coronary perfusion pressure remains unknown although studies examining compression-to-ventilation ratios higher than 15:2 (C:V) in animals have reported higher C:V to be superior for return of spontaneous circulation and neurologic outcome. We examined human performance of two-rescuer CPR using various C:V.

METHODS

Thirty six EMT-Basic students in their final week of training performed two-rescuer CPR using C:V of 15:2, 30:2, 40:2, 50:2, and 60:2 on a recording resuscitation manikin. Compression and ventilation variables were recorded by computer while the number of pauses for ventilations and the hands-off time (time not spent performing chest compressions) were abstracted by hand. Data were analyzed by ANOVA and significant differences from the standard treatment of C:V = 15:2 were assessed by Tukey's HSD post hoc test.

FINDINGS

The number of compressions delivered per minute increased with increasing C:V while the hands-off time and pauses for ventilations decreased. All comparisons were significantly different from C:V = 15:2 (P < 0.001). The ventilation numbers decreased with increasing C:V although mean minute volume exceeded 1l for all C:V.

INTERPRETATION

A 15:2 compression-to-ventilation ratio when performed during two-rescuer CPR results in 26s of hands off time each minute while only delivering 60 compressions. Alternative C:V ratios of 30:2, 40:2, 50:2, and 60:2 all exceed the AHA recommended 80 compressions/min while still delivering a minute volume in excess of 1l.

Modified cardiopulmonary resuscitation (CPR) instruction protocols for emergency medical dispatchers: rationale and recommendations

BACKGROUND

International consensus guidelines now support the use of "chest compressions-only" cardiopulmonary resuscitation (CPR) instructions (CCOIs) by emergency medical dispatch (EMD) personnel providing telephone assistance to untrained bystanders at a cardiac arrest scene. These guidelines are based largely on evolving experimental data and a clinical trial conducted in one venue with distinct emergency medical services (EMS) system features. Accordingly, the Council of Standards for the National Academies of Emergency Dispatch was asked to adapt a modified telephone CPR protocol, and specifically one that could be applied more broadly to the spectrum of EMS systems.

METHODS

A group of international EMD specialists, researchers and professional association representatives analyzed available scientific data and considered variations in EMS systems, particularly those in Europe and North America.

RESULTS AND CONCLUSIONS

Several recommendations were established: (1) to avoid confusion, bystanders already providing CPR should continue those previously learned methods; (2) following a sudden collapse unlikely to be of respiratory etiology, CCOIs should be provided when the bystander is not CPR-trained, declining to perform mouth-to-mouth ventilation or unsure of actions to take; (3) following 4 min of CCOIs, ventilations can be provided, but, for now, only at a compression-ventilation ratio of 100:2 until EMS arrives; (4) until more data become available, dispatchers should follow existing compression-ventilation protocols for children and adult cases involving probable respiratory/trauma etiologies; (5) EMD CPR protocols should account for EMS system features and receive quality oversight and expert medical direction.

Differences in time to defibrillation and intubation between two different ventilation/compression ratios in simulated cardiac arrest

OBJECTIVE

During basic life support (BLS) by a two-rescuer-team early defibrillation and ALS procedures should be performed without interruptions of the BLS-ventilation/compression sequence. The objective of this study was to determine the impact of a ventilation/compression ratio of 5:50 versus 2:15 on the time intervals "Start BLS to first shock" and "Start BLS to intubation".

METHODS

Using a random cross over design 40 experienced paramedics performed a standard BLS/ALS-algorithm according to ILCOR guidelines in a manikin model with ventricular fibrillation (resusci skillreporter anne, Laerdal, Norway) performing both the 2:15 and the 5:50 ventilation/compression ratio. BLS was started with bag/valve/mask ventilation, a semi-automatic defibrillator (corpuls 08/16S) was connected with the manikin, ECG-analysis and three shocks were performed and the tracheal intubation was prepared. Ventilation/compression sequence was only interrupted during ECG-analysis and defibrillation. Expiratory volumes and number of compressions were measured. Variables were compared using paired Students t-test. In addition paramedics were interviewed about work-flow and emotional stress during the tests.

RESULTS

The time interval "Start BLS to first shock" was 78 s (2:15-group) versus 63 s (5:50-group), p<0.0001, the time interval "Start BLS to intubation" was 183 s (2:15-group) versus 150 s (5:50-group), p<0.0001, mean ventilation volumes per minute were 4490 ml (2:15-group) versus 4370 ml (5:50-group), p>0.1, mean number of compressions were 65 min-1. (2:15-group) versus 68 min-1 (5:50-group), p>0.1. The work-flow and emotional stress was appraised by the paramedics to be significantly superior in the 5:50 ratio (p<0.0001).

CONCLUSIONS

The ventilation/compression ratio of 5:50 compared with 2:15 during BLS with an unsecured airway reduces the time until the first defibrillation and tracheal intubation was performed without changes in ventilation volume and compressions per minute. The Paramedics stated that the 5:50 ratio improved the work-flow and reduced the emotional stress.

The ABC of resuscitation and the Dutch (re)treat

In 1982 the Netherlands made a unilateral decision to change the established airway-breathing-circulation (ABC) training sequence to a different approach that stressed efficiency in diagnosis and treatment. This Dutch approach became known as the CAB (circulation-airway-breathing) sequence. Twenty years later, being confronted with the new international guidelines (published 2000) that still use the ABC approach, the Netherlands Resuscitation Council (NRR) questioned again the validity of our persistence in using the "Dutch variant" of resuscitation. This resulted in revised national guidelines that conform again with the international guidelines. This article restates the main rationale and arguments behind the original decision to change to a Dutch (CAB) version of resuscitation over 20 years ago. The national decision to adopt the ABC approach once again was mainly to prevent resuscitation in the Netherlands from being isolated from the rest of the world and was not based on present knowledge of physiology and resuscitation. The authors hope that this article will open the discussion once again.

An alternative approach to advancing resuscitation science

Stagnant survival rates in out-of-hospital cardiac arrest remain a great impetus for advancing resuscitation science. International resuscitation guidelines, with all their advantages for standardizing resuscitation therapeutic protocols, can be difficult to change. A formalized evidence-based process has been adopted by the International Liason Committee on Resuscitation (ILCOR) in formulating such guidelines. Currently, randomized clinical trials are considered optimal evidence, and very few major changes in the Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care are made without such. An alternative approach is to allow externally controlled clinical trials more weight in Guideline formulation and resuscitation protocol adoption. In Tucson, Arizona (USA), the Fire Department cardiac arrest database has revealed a number of resuscitation issues. These include a poor bystander CPR rate, a lack of response to initial defibrillation after prolonged ventricular fibrillation, and substantial time without chest compressions during the resuscitation effort. A local change in our previous resuscitation protocols had been instituted based upon this historical database information.

Optimum cardiopulmonary resuscitation for basic and advanced life support: a simulation study

Optimum cardiopulmonary resuscitation (CPR) for both basic and advanced cardiac life support depends on a compromise between the number of chest compressions delivered and the amount of ventilation provided. This study used theoretical models of blood flow and both arterial and venous blood gas values to investigate the influence of different compression to ventilation ratios on CPR efficiency, as well as the effects of different inspired oxygen concentrations. With mouth-to-mouth ventilation, greater numbers of compressions between each ventilation provided progressively greater blood flow. However, a greater the number of compressions, reduced the arterial oxygen levels and carbon dioxide clearance. There was an optimum ratio, in terms of both oxygen delivery and carbon dioxide clearance, of around 20:1 compressions to ventilation. Optimum oxygen delivery was 0.19 L/min at 20:1, which was better than the oxygen delivery for standard CPR based on a ratio of 15:2 (0.13 L/min). When patients were ventilated with supplemental oxygen (either 50 or 85%) the lungs rapidly became saturated with oxygen, and oxygen delivery depended more on blood flow. Higher numbers of compressions provided greater oxygen delivery, but at the cost of increasing hypercarbia, which is thought to affect resuscitation success rates adversely. The simulation results suggested ratios around 20:1 would be the best compromise between blood flow, oxygen delivery (0.25 L/min) and avoidance of hypercarbia. The best results were provided by continuous chest compressions and simultaneous, asynchronous ventilation in an intubated patient. Arterial and venous oxygen and carbon dioxide levels were well maintained, with very good oxygen delivery (0.32 L/min). Intubation with continuous chest compressions and asynchronous ventilation can therefore significantly improve the quality of CPR as a whole, and not just ventilation.

["Topless" cardiopulmonary resuscitation. Fashion or science?]

A decade after the onset of a discussion whether ventilation could be omitted from bystander basic life support (BLS) algorithms, the state of the evidence is reevaluated. Initial animal studies and a prospective randomized patient trial had suggested that omission of ventilation during the first minutes of lay cardiopulmonary resuscitation (CPR) did not impair patient outcomes. More recent studies demonstrate, however, that this may hold true only in very specific scenarios, and that the chest compression-only technique was never superior to standard BLS. Instead of calling basics of BLS training and practice into question, more and better training of lay persons and professionals appears mandatory, and targeted use of dispatcher-guided telephone CPR should be evaluated and, if it improves outcome, it should be encouraged. Future studies should focus much less on the omission but on the optimization of ventilation under the specific conditions of CPR.

Uninterrupted chest compression CPR is easier to perform and remember than standard CPR

INTRODUCTION

It has long been observed that CPR skills rapidly decline regardless of the modality used for teaching or criteria used for testing. Uninterrupted chest compression CPR (UCC-CPR) is a proposed alternative to standard single rescuer CPR (STD-CPR) for laypersons in witnessed unexpected cardiac arrest in adults. It delivers substantially more compressions per minute and may be easier to remember and perform than standard CPR.

METHODS

In this prospective study, 28 medical students were taught STD-CPR and UCC-CPR and then were tested on each method at baseline (0), 6, and 18 months after training. The students' performance for at least 90 s of CPR was evaluated based on video and Laerdal Skillreporter Resusci Anne recordings.

RESULTS

The mean number of correct chest compressions delivered per minute trended down over time in STD-CPR (23 +/- 3, 19 +/- 4 , and 15 +/- 3; P = 0.09) but stayed the same in UCC-CPR (43 +/- 9, 38 +/- 7, and 37 +/- 7 = 0.91) at 0, 6, and 18 months, respectively. The mean percentage of chest compressions delivered correctly fell over time in STD-CPR (54 +/- 6%, 35 +/- 6%, and 32 +/- 6%; P = 0.02) but stayed the same in UCC-CPR (34 +/- 5%, 41 +/- 7%, and 38 +/- 8%) at 0, 6, and 18 months, respectively. The number of chest compressions delivered per minute was higher in UCC-CPR at 0, 6, and 18 months (113 versus 44, P < 0.0001; 94 versus 47, P < 0.0001; and 92 versus 44, P < 0.001). The greater number of chest compressions was due to a mean ventilaroty pause of 13-14 s during STD-CPR at all three time points.

CONCLUSIONS

Chest compression performance during STD-CPR declined in repeated testing over 18 months whereas there was minimal decline in chest compressions performance on repeated testing of UCC-CPR. In addition, substantially more chest compressions were delivered during UCC-CPR compared to STD-CPR at all time points primarily because of long pauses accompanying rescue breathing.

Single-rescuer cardiopulmonary resuscitation: ‘two quick breaths’—an oxymoron

The Guidelines 2000 for CPR and ECC recommend for single lay-rescuers performing basic life support, "two quick breaths followed by 15 chest compressions", repeated until professional help arrives. It is uncertain that this can actually be accomplished by the majority of lay rescuers. We evaluated 53 first-year medical students after completing BLS CPR training to determine if they could deliver the goal of 80 compressions per minute when following this AHA BLS recommendation. Alternatively, a simplified technique of uninterrupted chest compression (UCC) BLS CPR was also taught and compared with standard BLS CPR (STD). The mean number of chest compressions/minute delivered with AHA BLS CPR was only 43 +/- 1 immediately after initial training and 49 +/- 2 when tested 6 months later. Uninterrupted chest compression BLS resulted in 113 +/- 2 compressions/min delivered immediately after training and 91 +/- 4 six months later (STD versus UCC; P < 0.0001). The mean length of time needed to provide the two breaths during STD-CPR was 14 +/- 1 and 12 +/- 1s (immediately after first training and six months after training). For STD-CPR, the mean minute ventilation was poor immediately after initial training (3.3 +/- 0.3 l/min) and further declined (1.9 +/- 0.4 l/min) at 6 months (P = 0.003). For single rescuer basic cardiopulmonary resuscitation, motivated BLS CPR-trained medical students take nearly as long as previously reported for middle-aged lay individuals to deliver these "two quick breaths". The "Guidelines 2000" recommendation for "two quick breaths" is an oxymoron, as it averages more than 13s. New recommendations for single-rescuer CPR should be considered that emphasize uninterrupted chest compressions.

Arterial blood gases with 700 ml tidal volumes during out-of-hospital CPR

The optimal tidal and minute ventilation during cardiopulmonary resuscitation (CPR) is not known. In the present study seven adult, non-traumatic, out-of-hospital cardiac arrest patients were intubated and mechanically ventilated at 12 min(-1) with 100% oxygen and a tidal volume of 700 ml (10 +/- 2 ml kg(-1)). Arterial blood gas samples were analysed after 6-8 min of unsuccessful resuscitation and mechanical ventilation. Mean PaCO2 was 5.2 +/- 1.3 kPa and mean PaO2 30.7 +/- 17.2 kPa. The patient with the highest (14 ml kg(-1)) and lowest (8 ml kg(-1)) tidal volumes per kg had the lowest and highest PaCO2 values of 2.6 and 6.8 kPa, respectively. Linear regression analysis confirmed a significant correlation between arterial pCO2 and tidal volume in ml/kg, r2 = 0.87. We conclude that aiming for an estimated ventilation of 10 ml kg(-1) tidal volume at frequency of 12 min(-1) might be expected to achieve normocapnia during ALS.

Oxygen delivery and return of spontaneous circulation with ventilation:compression ratio 2:30 versus chest compressions only CPR in pigs

The need for rescue breathing during the initial management of sudden cardiac arrest is currently being debated and reevaluated. The present study was designed to compare cerebral oxygen delivery during basic life support (BLS) by chest compressions only with chest compressions plus ventilation in pigs with an obstructed airway mimicked by a valve hindering passive inhalation. Resuscitability was then studied during the subsequent advanced life support (ALS) period. After 3 min of untreated ventricular fibrillation (VF) BLS was started. The animals were randomised into two groups. One group received chest compressions only. The other group received ventilations and chest compressions with a ratio of 2:30. A gas mixture of 17% oxygen and 4% carbon dioxide was used for ventilation during BLS. After 10 min of BLS, ALS was provided. All six pigs ventilated during BLS attained a return of spontaneous circulation (ROSC) within the first 2 min of advanced cardiopulmonary resuscitation (CPR) compared with only one of six compressions-only pigs. While all except one compressions-only animal achieved ROSC before the experiment was terminated, the median time to ROSC was shorter in the ventilated group. With a ventilation:compression ratio of 2:30 the arterial oxygen content stayed at 2/3 of normal, but with compressions-only, the arterial blood was virtually desaturated with no arterio-venous oxygen difference within 1.5-2 min. Haemodynamic data did not differ between the groups. In this model of very ideal BLS, ventilation improved arterial oxygenation and the median time to ROSC was shorter. We believe that in cardiac arrest with an obstructed airway, pulmonary ventilation should still be strongly recommended.

A comparison between over-the-head and standard cardiopulmonary resuscitation

BACKGROUND

Standard cardiopulmonary resuscitation (CPR) is performed by kneeling adjacent to the side of the casualty. In certain circumstances it may be difficult or impossible to perform CPR in this position, for example in confined spaces such as a narrow corridor, aircraft or train gangway. The aim of this study was to investigate the technique of over-the-head CPR (OTH CPR), where the CPR provider kneels above the casualty and performs chest compressions OTH of the casualty.

METHODS

Twenty volunteers were randomised to a cross over trial where they performed standard and OTH CPR at a 7-day interval. Compression and ventilation variables were recorded on the Laerdal Resusci Annie VAM system.

RESULTS

Chest compression depth and ventilation volume declined over time (0-3 min P < 0.001). There was no difference in compression rate, depth, duty cycle or ventilation rate, inflation rate and ventilation volume between techniques. Hand position was incorrect more frequently in the standard compared to the OTH group (incorrect compressions 300 versus 76, respectively, P < 0.001) due principally to a greater proportion of low positioned compressions in the standard CPR group.

CONCLUSION

OTH CPR appears equally effective as standard CPR with some marginal advantages in correct hand placement. We suggest that in situations where it is not possible to perform standard CPR, OTH CPR may be considered as a suitable alternative.

To blow or not to blow: a randomised controlled trial of compression-only and standard telephone CPR instructions in simulated cardiac arrest

This randomised controlled trial used a manikin model of cardiac arrest to compare skill performance in untrained lay persons randomised to receive either compression-only telephone CPR (Compression-only tel., n=29) or standard telephone CPR instructions (Standard tel., n=30). Performance was evaluated during standardised 10 min cardiac arrest simulations using a video recording and data from a laptop computer connected to the training manikin. A number of subjects in both groups did not open the airway. More than 75% in the Standard tel. group failed to deliver two effective initial rescue breaths, and only 17% provided an adequate inflation volume for subsequent breaths, delivering a median of only five inflations during the entire scenario. Most subjects in both groups gave chest compressions that were too shallow and at an inappropriately rapid rate. Hand position was also poor, but was worse in the group given simplified instructions. There was a significant delay to first compression in both groups, although this interval was shortened by over a minute when ventilations were eliminated from the telephone instruction algorithm (245 vs. 184 s, P<0.001). Over two-and-a-half times as many chest compressions were delivered during an average ambulance response time with compression-only telephone directions compared with standard CPR (461 vs. 186, P<0.001). These variables may be critical in predicting survival from out-of-hospital cardiac arrest. Further research is necessary to establish if modifications to scripted telephone instructions can remedy the identified performance deficiencies. Eliminating instructions for rescue breaths from scripted telephone directions will have little impact on the ventilation of most patients. Research is required to determine if the consequent reduction in the delay to starting chest compressions and the significant increase in the number of compressions delivered can increase survival from out-of-hospital cardiac arrest.

Quality of CPR with three different ventilation:compression ratios

Current adult basic cardiopulmonary resuscitation (CPR) guidelines recommend a 2:15 ventilation:compression ratio, while the optimal ratio is unknown. This study was designed to compare arterial and mixed venous blood gas changes and cerebral circulation and oxygen delivery with ventilation:compression ratios of 2:15, 2:50 and 5:50 in a model of basic CPR. Ventricular fibrillation (VF) was induced in 12 anaesthetised pigs, and satisfactory recordings were obtained from 9 of them. A non-intervention interval of 3 min was followed by CPR with pauses in compressions for ventilation with 17% oxygen and 4% carbon dioxide in a randomised, cross-over design with each method being used for 5 min. Pulmonary gas exchange was clearly superior with a ventilation:compression ratio of 2:15. While the arterial oxygen saturation stayed above 80% throughout CPR for 2:15, it dropped below 40% during part of the ventilation:compression cycle for both the other two ratios. On the other hand, the ratio 2:50 produced 30% more chest compressions per minute than either of the two other methods. This resulted in a mean carotid flow that was significantly higher with the ratio of 2:50 than with 5:50 while 2:15 was not significantly different from either. The mean cerebrocortical microcirculation was approximately 37% of pre-VF levels during compression cycles alone with no significant differences between the methods. The oxygen delivery to the brain was higher for the ratio of 2:15 than for either 5:50 or 2:50. In parallel the central venous oxygenation, which gives some indication of tissue oxygenation, was higher for the ratio of 2:15 than for both 5:50 and 2:50. As the compressions were done with a mechanical device with only 2-3 s pauses per ventilation, the data cannot be extrapolated to laypersons who have great variations in quality of CPR. However, it might seem reasonable to suggest that basic CPR by professionals should continue with ratio of 2:15 at present if it can be shown that similar brief pauses for ventilation can be achieved in clinical practice.

Updates in Pediatrics Basic Life Support:An Evidence-Based Review

The American Heart Association, together with representatives from the International Liaison Committee on Resuscitation (ILCOR), which is made up of leading resuscitation organizations from the Americas, Europe, Southern Africa, Australia, and New Zealand, undertook a series of evidence-based evaluations of the science of resuscitation which culminated in the publication of ’Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care’ in August 2000 tL2). Experts from non-ILCOR organizations from Asia and elsewhere also participated in drawing up the guidelines.

Dispatcher-assisted cardiopulmonary resuscitation. An evaluation of efficacy amongst elderly

Bystander cardiopulmonary resuscitation (CPR) increases survival rates. The largest group of cardiac arrest patients are men over the age of 60 in the home, and the most probable potential CPR provider is an older woman who is not likely to have received CPR training. One method to increase the percentage of bystander-initiated CPR in this setting is for CPR instruction to be provided by nurse dispatchers via telephone. Two male and 18 female volunteers with a median age of 78 years and no previous CPR experience performed 9 min of telephone assisted CPR on a manikin. They were randomised to receive telephone instructions in chest compressions alone or standard CPR including mouth-to-mouth ventilation. Variables were registered by a recording manikin, visual observations, and video and audiotape recordings. The median period from dispatcher contact until continuous CPR was significantly longer for standard instructions than for compression only, 4.9 versus 3.4 min, and fewer chest compressions were provided during the 9 min test period, median 124 versus 334 compressions. In both groups the overall CPR performance was of very poor quality, and unlikely to have affected outcome in a real situation. Other telephone assisted CPR scripts should be tested in this potential bystander group.