Cardiopulmonary resuscitation for cardiac arrest: the importance of uninterrupted chest compressions in cardiac arrest resuscitation

Systematic review of the mechanisms driving effective blood flow during adult CPR

BACKGROUND

High quality chest compressions is the most significant factor related to improved short-term and long-term outcome in cardiac arrest. However, considerable controversy exists over the mechanisms involved in driving blood flow.

OBJECTIVES

The aim of this systematic review is to elucidate major mechanisms involved in effective compression-mediated blood flow during adult cardiopulmonary resuscitation (CPR).

DESIGN AND SETTING

Systematic review of studies identified from the bibliographic databases of PubMed/Medline, Cochrane, and Scopus.

SELECTION CRITERIA

All human and animal studies including information on the responsible mechanisms of compression-related blood flow.

DATA COLLECTION AND ANALYSIS

Two reviewers (MG, TX) independently screened all potentially relevant titles and abstracts for eligibility, by using a standardized data-worksheet.

MAIN RESULTS

Forty seven studies met the inclusion criteria. Because of the heterogeneity in outcome measures, quantitative synthesis of evidence was not feasible. Evidence was critically synthesized in order to answer the review questions, taking into account study heterogeneity and validity. The number of included studies per category is as follows: blood flow during chest compression, nine studies; blood flow during chest decompression, six studies; effect of chest compression on cerebral blood flow, eight studies; active compression-decompression CPR, 14 studies; and effect of ventilation on compression-related blood flow, 13 studies.

CONCLUSION

The evidence so far is inconclusive regarding the major responsible mechanism in compression-related blood flow. Although both 'cardiac pump' and 'thoracic pump' have a key role, the effect of each mechanism is highly depended on other resuscitation parameters, such as positive pressure ventilation and compression depth.

Time matters--realism in resuscitation training

BACKGROUND

The advanced life support guidelines recommend 2min of cardiopulmonary resuscitation (CPR) and minimal hands-off time to ensure sufficient cardiac and cerebral perfusion. We have observed doctors who shorten the CPR intervals during resuscitation attempts. During simulation-based resuscitation training, the recommended 2-min CPR cycles are often deliberately decreased in order to increase the number of scenarios. The aim of this study was to test if keeping 2-min CPR cycles during resuscitation training ensures better adherence to time during resuscitation in a simulated setting.

METHODS

This study was designed as a randomised control trial. Fifty-four 4th-year medical students with no prior advanced resuscitation training participated in an extra-curricular one-day advanced life support course. Participants were either randomised to simulation-based training using real-time (120s) or shortened CPR cycles (30-45s instead of 120s) in the scenarios. Adherence to time was measured using the European Resuscitation Council's Cardiac Arrest Simulation Test (CASTest) in retention tests conducted one and 12 weeks after the course.

RESULTS

The real-time group adhered significantly better to the recommended 2-min CPR cycles (time-120s) (mean 13; standard derivation (SD) 8) than the shortened CPR cycle group (mean 45; SD 19) when tested (p<0.001.)

CONCLUSION

This study indicates that time is an important part of fidelity. Variables critical for performance, like adherence to time in resuscitation, should therefore be kept realistic during training to optimise outcome.

Comparing three CPR feedback devices and standard BLS in a single rescuer scenario: a randomised simulation study

BACKGROUND

Efficiently performed basic life support (BLS) after cardiac arrest is proven to be effective. However, cardiopulmonary resuscitation (CPR) is strenuous and rescuers' performance declines rapidly over time. Audio-visual feedback devices reporting CPR quality may prevent this decline. We aimed to investigate the effect of various CPR feedback devices on CPR quality.

METHODS

In this open, prospective, randomised, controlled trial we compared three CPR feedback devices (PocketCPR, CPRmeter, iPhone app PocketCPR) with standard BLS without feedback in a simulated scenario. 240 trained medical students performed single rescuer BLS on a manikin for 8min. Effective compression (compressions with correct depth, pressure point and sufficient decompression) as well as compression rate, flow time fraction and ventilation parameters were compared between the four groups.

RESULTS

Study participants using the PocketCPR performed 17±19% effective compressions compared to 32±28% with CPRmeter, 25±27% with the iPhone app PocketCPR, and 35±30% applying standard BLS (PocketCPR vs. CPRmeter p=0.007, PocketCPR vs. standard BLS p=0.001, others: ns). PocketCPR and CPRmeter prevented a decline in effective compression over time, but overall performance in the PocketCPR group was considerably inferior to standard BLS. Compression depth and rate were within the range recommended in the guidelines in all groups.

CONCLUSION

While we found differences between the investigated CPR feedback devices, overall BLS quality was suboptimal in all groups. Surprisingly, effective compression was not improved by any CPR feedback device compared to standard BLS. All feedback devices caused substantial delay in starting CPR, which may worsen outcome.

Epidemiology and outcome analysis of children with traumatic out-of-hospital cardiac arrest compared to nontraumatic cardiac arrest

PURPOSE

This study aimed to determine predictive factors for sustained return of spontaneous circulation (ROSC) in pediatric patients with traumatic out-of-hospital cardiac arrest (OHCA) and compared to those with nontraumatic OHCA.

METHODS

This was a retrospective prognostic study of children with OHCA presenting to the emergency department (ED) was conducted from 2005 to 2010. Related clinical factors that influenced sustained ROSC in traumatic OHCA patients were identified and compared to nontraumatic cases. Significant parameters in predicting sustained ROSC in traumatic OHCA children were also determined using multivariate logistic regression analysis, and etiologies of the ICU admissions were analyzed in patients with sustained ROSC.

RESULTS

Among 2,978 critically ill children admitted to the ED, 150 were pediatric OHCA patients, including 76 traumatic cases and 74 nontraumatic cases. Of children with OHCA, initial sustained ROSC was achieved in 51 cases (34.0 %), including 31 traumatic cases and 20 of nontraumatic cases. Head and neck injuries were the majority of traumatic cases in the traumatic OHCA children, followed by abdominal injuries and chest injuries. However, abdominal injuries accounted for the highest rate to gain sustained ROSC, while chest injuries had the lowest rate for successful sustained ROSC. Significant factors associated with sustained ROSC in traumatic OHCA included initial cardiac rhythm (P < 0.05), the period from scene to hospital (P < 0.05), and the duration of in-hospital cardiopulmonary resuscitation (CPR) (P < 0.05).

CONCLUSIONS

Significant factors related to sustained ROSC have been identified as initial cardiac rhythm, duration of in-hospital CPR, and the period from scene to hospital. Head and neck injuries were the majority of traumatic cases and the prevention in head and neck trauma may play an important part in public health aspects.