Time for change?

Witnessed resuscitation: A concept analysis

The science and practice of resuscitation is recognised and endorsed on an international level, yet for more than a decade it has appeared in the literature alongside words such as witnessing or witnessed to signify the practice of family presence during a resuscitation attempt. This paper explores the meaning of witnessed resuscitation using the process for concept analysis proposed by Rodgers. The term resuscitation is explored, followed by identification of relevant uses of the concept of witnessed resuscitation. The reader is introduced to conceptual variations that challenge the way in which the concept has become associated with family or relatives presence in the resuscitation room of an accident and emergency department. Conceptual clarity is further enhanced through the identification of references, antecedents and consequences of witnessed resuscitation and by providing a model case of the concept that includes its defining attributes.

Treatment of out-of-hospital cardiac arrest with LUCAS, a new device for automatic mechanical compression and active decompression resuscitation

Lund University Cardiopulmonary Assist System (LUCAS) is a new gas-driven CPR device providing automatic chest compression and active decompression. This is a report of the first 100 consecutive cases treated with LUCAS due to out-of-hospital cardiac arrest (58% asystole, 42% ventricular fibrillation (VF)). Safety aspects were also investigated and it was found that LUCAS can be used safely regarding noise levels and oxygen concentrations within the ambulance. A crash test (10G) showed no displacement of the device from the manikin. Of the 71 patients with witnessed cardiac arrest, 39% received bystander CPR. In those 28 patients where LUCAS-CPR was initiated more than 15 min after the ambulance alarm and in the 29 unwitnessed cases, none survived for 30 days. Of the 43 witnessed cases treated with LUCAS within 15 min, 24 had VF and 15 (63%) of these cases achieved a stable return of spontaneous circulation (ROSC) and 6 (25%) of them survived with a good neurological recovery after 30 days; 5 (26%) of the 19 patients with asystole achieved ROSC and 1 (5%) survived for over 30 days. One patient where ROSC could not be achieved was transported with on-going LUCAS-CPR to the catheter laboratory and after PCI for an occluded LAD a stable ROSC occurred, but the patient never regained consciousness and died 15 days later. To conclude, establishment of an adequate cerebral circulation as quickly as possible after cardiac arrest is mandatory for a good outcome. In this report patients with a witnessed cardiac arrest receiving LUCAS-CPR within 15 min from the ambulance call had a 30-day survival of 25% in VF and 5% in asystole, but if the interval was more than 15 min, there were no 30-day survivors.

Automated External Defibrillators: To What Extent Does the Algorithm Delay CPR?

STUDY OBJECTIVE

Maximizing cardiopulmonary resuscitation (CPR) during resuscitation may improve survival. Resuscitation protocols stack up to 3 shocks to achieve defibrillation, followed by an immediate postdefibrillation pulse check. The purpose of this study is to evaluate outcomes of rhythm reanalyses immediately after shock, stacked shocks, and initial postshock pulse checks in relation to achieving a pulse and initiating CPR.

METHODS

We conducted an observational study of patients with ventricular fibrillation treated by first-tier emergency medical services (EMS). We collected data from EMS, dispatch, and hospital records. Additionally, we analyzed automatic external defibrillator recordings to determine the proportion of cardiac arrest victims who were defibrillated and achieved a pulse according to shock number (single versus stacked shock), proportion of victims with a pulse during the initial postdefibrillation pulse check, and interval from initial shock to CPR.

RESULTS

The study included 481 cardiac arrest subjects. Automatic external defibrillators terminated ventricular fibrillation with the initial shock in 83.6% (n=402) of cases. A second shock terminated ventricular fibrillation in an additional 7.5% (n=36) of cases, and a third shock terminated ventricular fibrillation in 4.8% (n=23) of cases. The initial sequence of 3 shocks failed to terminate ventricular fibrillation in 4.1% (n=20) of cases. In total, automatic external defibrillators performed 560 rhythm reanalyses during the initial shock sequence and delivered 122 "stacked" shocks. Termination of ventricular fibrillation was not synonymous with return of a pulse. The initial shock produced a pulse that was eventually detected in 21.8% (105/481) of cases. Stacked shocks produced a pulse in 10.7% (13/122) of cases. For the 24.5 % (n=118) of cases in which a pulse returned, the pulse was detected during the initial postshock pulse check only 12 times, or 2.5% of all cases. The median interval from initial shock until CPR was 29 (23,41) seconds.

CONCLUSION

Rhythm reanalyses, stacked shocks, and postshock pulse checks had low yield for achieving or detecting return of a pulse. CPR was not initiated until 29 seconds after the initial shock.

Better adherence to the guidelines during cardiopulmonary resuscitation through the provision of audio-prompts

OBJECTIVE

Quality assurance to optimize clinical resuscitation performance is important. The aims of the present study were to identify the deficiencies in the clinical practice of resuscitation by motion analysis of video-recorded cardiopulmonary resuscitation (CPR), and to evaluate the effectiveness of quality improvement strategies based on audio-prompt methods.

MATERIALS AND METHODS

A two-stage prospective trial was conducted. The first stage (observation group) was designed to identify any major clinical nonconformity to current resuscitation guidelines by videotaped CPR sessions. The second stage (intervention group) was designed to evaluate the effectiveness of audio prompts in ameliorating the problems identified at the first stage. The demographic data of patients and CPR variables between the two groups were analysed.

RESULTS

A total of 30 resuscitation attempts were recorded during study period: 17 patients were in the observation group and 13 patients in the intervention group. Inadequate number of chest compressions per minute, lack of re-oxygenation during prolonged intubation attempts and unnecessary hands-off periods were identified as the three most important deficiencies in CPR practice. Compared to the observation group, the intervention group showed a significant improvement in the hands-off period per minute during CPR (12.7 +/- 5.3 s versus 16.9+/-7.9 s, P < 0.05), the total hands-off time during CPR (164 +/- 94 s versus 273 +/- 153 s, P < 0.05), the proportion of intubation attempts taking under 20 s (56.3% versus 10%, P < 0.05).

CONCLUSIONS

Audio-prompts can improve the adherence to current CPR guidelines in the clinical setting significantly. The quality improvement measures described in this study are helpful in translating CPR knowledge into clinical practice.

Magnetic resonance imaging during untreated ventricular fibrillation reveals prompt right ventricular overdistention without left ventricular volume loss

BACKGROUND

Most out-of-hospital ventricular fibrillation (VF) is prolonged (>5 minutes), and defibrillation from prolonged VF typically results in asystole or pulseless electrical activity. Recent visual epicardial observations in an open-chest, open-pericardium model of swine VF indicate that blood flows from the high-pressure arterial system to the lower-pressure venous system during untreated VF, thereby overdistending the right ventricle and apparently decreasing left ventricular size. Therefore, inadequate left ventricular stroke volume after defibrillation from prolonged VF has been postulated as a major contributor to the development of pulseless rhythms.

METHODS AND RESULTS

Ventricular dimensions were determined by MRI for 30 minutes of untreated VF in a closed-chest, closed-pericardium model in 6 swine. Within 1 minute of untreated VF, mean right ventricular volume increased by 29% but did not increase thereafter. During the first 5 minutes of untreated VF, mean left ventricular volume increased by 34%. Between 20 and 30 minutes of VF, stone heart occurred as manifested by dramatic thickening of the myocardium and concomitant substantial decreases in left ventricular volume.

CONCLUSIONS

In this closed-chest swine model of VF, substantial right ventricular volume changes occurred early and did not result in smaller left ventricular volumes. The changes in ventricular volumes before the late development of stone heart do not explain why defibrillation from brief duration VF (<5 minutes) typically results in a pulsatile rhythm with return of spontaneous circulation, whereas defibrillation from prolonged VF (5 to 15 minutes) does not.

[Transthoracic defibrillation. Physiologic and pathophysiologic principles and their role in the outcome of resuscitation]

As one major link in the chain of survival, early transthoracic (external) cardiac defibrillation is aimed at the termination of ventricular flutter and ventricular fibrillation. Most important to the success of defibrillation is the passage of a defined amount of current through a critical mass of heart muscle. Different transthoracic resistances reduce the effective density of the current within the heart. As for other therapeutic intervention procedures, recommendations for the optimal strength of current to be applied to the fibrillating heart need to be evaluated and defined for therapeutical defibrillation too. Unnecessarily high current density causes damage to the heart and should be prevented. By using biphasic waveforms in contrast to monophasic impulses, the amount of current can be reduced but the same or even higher efficacy is attained. Therefore possible myocardial damage might be clearly reduced. Even with individually altered thoracic impedance effective conversion of cardiac rhythm can be achieved by device-controlled compensation and biphasic waveforms. According to their different mechanisms or origin (electrically induced or spontaneously caused by organic heart disease) the probability of successful conversion of the cardiac rhythm by one single electrical impulse varies. The optimum point in time for defibrillation during resuscitation needs to be redefined. In order to improve comparability, further studies should use standardized definitions for successful defibrillation relating to the resulting cardiac rhythm.