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

Effectiveness of bystander-initiated cardiac-only resuscitation for patients with out-of-hospital cardiac arrest

BACKGROUND

Previous animal and clinical studies suggest that bystander-initiated cardiac-only resuscitation may be superior to conventional cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrests. Our hypothesis was that both cardiac-only bystander resuscitation and conventional bystander CPR would improve outcomes from out-of-hospital cardiac arrests of < or = 15 minutes' duration, whereas the addition of rescue breathing would improve outcomes for cardiac arrests lasting > 15 minutes.

METHODS AND RESULTS

We carried out a prospective, population-based, observational study involving consecutive patients with emergency responder resuscitation attempts from May 1, 1998, through April 30, 2003. The primary outcome measure was 1-year survival with favorable neurological outcome. Multivariable logistic regression analysis was performed to evaluate the relationship between type of CPR and outcomes. Among the 4902 witnessed cardiac arrests, 783 received conventional CPR, and 544 received cardiac-only resuscitation. Excluding very-long-duration cardiac arrests (> 15 minutes), the cardiac-only resuscitation yielded a higher rate of 1-year survival with favorable neurological outcome than no bystander CPR (4.3% versus 2.5%; odds ratio, 1.72; 95% CI, 1.01 to 2.95), and conventional CPR showed similar effectiveness (4.1%; odds ratio, 1.57; 95% CI, 0.95 to 2.60). For the very-long-duration arrests, neurologically favorable 1-year survival was greater in the conventional CPR group, but there were few survivors regardless of the type of bystander CPR (0.3% [2 of 624], 0% [0 of 92], and 2.2% [3 of 139] in the no bystander CPR, cardiac-only CPR, and conventional CPR groups, respectively; P<0.05).

CONCLUSIONS

Bystander-initiated cardiac-only resuscitation and conventional CPR are similarly effective for most adult out-of-hospital cardiac arrests. For very prolonged cardiac arrests, the addition of rescue breathing may be of some help.

The physiological effect on rescuers of doing 2min of uninterrupted chest compressions

OBJECTIVES

To analyse how rescuers tolerate the effort derived of giving uninterrupted chest compressions during 2min.

MATERIALS AND METHODS

Twenty-three healthy volunteers, nurses and doctors of the Intensive Care Unit (ICU), members of the hospital cardiac arrest team, were enrolled in the study. Using a training manikin, participants were asked to perform chest compressions during 2min at a rate of 100min(-1). The oxygen saturation and cardiac rate of the subjects were monitored using pulse oximetry before and after one and 2min performing chest compressions. The percentage of the maximal heart rate of the rescuer over the theoretical maximum allowed in a conventional stress test was calculated, taking into account age and body mass index (BMI) of the subjects. Fatigue was measured using a visual analogical scale (VAS).

RESULTS

The means (+/-S.D.) of chest compressions in the first and second minutes were 103+/-12, and 104+/-11, respectively. The mean percent of the maximum heart rate observed was 61+/-8%. None of the subjects had difficulties to complete the test. All subjects recovered their basal values in less than 2min, and the mean value recorded in the VAS was 3+/-2.

CONCLUSIONS

The practice of uninterrupted chest compressions during 2min by the same rescuer is well tolerated by health professionals trained in cardiopulmonary resuscitation (CPR).

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.

An evaluation of objective feedback in basic life support (BLS) training

BACKGROUND

Studies show that acquisition and retention of BLS skills is poor, and this may contribute to low survival from cardiac arrest. Feedback from instructors during BLS training is often lacking. This study investigates the effects of continuous feedback from a manikin on chest compression and ventilation techniques during training compared to instructor feedback alone.

MATERIALS AND METHODS

A prospective randomised controlled trial. First-year healthcare students at the University of Birmingham were randomised to receive training in standard or feedback groups. The standard group were taught by an instructor using a conventional manikin. The feedback group used a 'Skillreporter' manikin, which provides continuous feedback on ventilation volume and chest compression depth and rate in addition to instructor feedback. Skill acquisition was tested immediately after training and 6 weeks later.

RESULTS

Ninety-eight participants were recruited (conventional n=49; Skillreporter n=49) and were tested after training. Sixty-six students returned (Skillreporter n=34; conventional n=32) for testing 6 weeks later. The Skillreporter group achieved better compression depth (39.96mm versus 36.71mm, P<0.05), and more correct compressions (58.0% versus 40.4%, P<0.05) at initial testing. The Skillreporter group also achieved more correct compressions at week 6 (43.1% versus 26.5%, P<0.05).

CONCLUSIONS

This study demonstrated that objective feedback during training improves the performance of BLS skills significantly when tested immediately after training and at re-testing 6 weeks later. However, CPR performance declined substantially over time in both groups.

Quality of lay person CPR performance with compression: ventilation ratios 15:2, 30:2 or continuous chest compressions without ventilations on manikins

The new CPR guidelines emphasise chest compression depth and have increased the compression:ventilation ratio to cause less time intervals without chest compressions. How this change may influence the quality of chest compressions is not documented. Sixty-eight volunteers among travellers at Oslo international airport and a senior citizen centre performed 5 min of CPR on a manikin with compression:ventilation ratios 15:2, 30:2 or continuous chest compressions. Median age was 37.5 years (range 15-87), 59% were men, and 71% reported CPR training median 8 years (3-15) previously. Three of 22, 4 of 23 and 3 of 23 subjects in the 15:2, 30:2 and continuous compressions groups respectively stopped before 5 min had passed. Mean compression depth was 41 +/- 11, 45 +/- 8 and 30 +/- 8 mm, respectively. Depth was reduced as a function of time in the continuous compression group. Number of compressions per minute was 40 +/- 9, 43 +/- 14 and 73 +/- 24 and percent no flow time 49 +/- 13%, 38 +/- 20% and 1 +/- 2%, respectively. In conclusion, continuous chest compressions without ventilations gave significantly more chest compressions per minute, but with decreased compression quality. No flow time for 30:2 was significantly less than for 15:2.

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.

Cardiopulmonary resuscitation algorithms, defibrillation and optimized ventilation during resuscitation

PURPOSE OF REVIEW

In 2005, the American Heart Association released its Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. This article reviews the treatment algorithms for Advanced Cardiac Life Support, citing the evidence on which the Guidelines are based. Additional focus is placed on defibrillation and optimized ventilation.

RECENT FINDINGS

Major changes include a reorganization of the algorithms for cardiac arrest. Emphasis on effective cardiopulmonary resuscitation is placed as the key to improved survival. Single defibrillation shocks are recommended (compared with three 'stacked' shocks) with immediate provision of cardiopulmonary resuscitation and minimal interruptions in chest compressions. The recommended chest compression : ventilation rate for single rescuers has been changed to 30:2.

SUMMARY

Despite advances in resuscitation science, basic life support remains the key to improving survival outcomes. Ultimately, as new knowledge is gained, we believe resuscitation therapies will be more individualized, on the basis of pathophysiology and etiology of the initial cardiac arrest.

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.