Problems associated with the Z-fold region of defibrillation electrodes

Common faults in resuscitation equipment--guidelines for checking equipment and drugs used in adult cardiopulmonary resuscitation

Successful advanced life support relies, in part, upon the availability and correct functioning of resuscitation equipment. However, numerous publications report deficiencies and defects in key items of resuscitation equipment, particularly those relating to airway management and defibrillation. Some of these are generic and relate to basic device failure (e.g. intrinsic design faults, manufacturing errors, random component failure), external factors (e.g. power failure, gas supply failure, electromagnetic interference) and human error (notably, inadequate knowledge, lack of experience and training, inadequate checking, insufficient maintenance). However, others are device specific. This paper identifies the common, generic faults that lead to equipment malfunction and recommends the resuscitation equipment essential for successful cardiopulmonary resuscitation. It also describes examples of specific equipment malfunction and makes suggestions for the nature and frequency of resuscitation equipment and drug checks, using a structured, and easy-to-recall list.

Effects of transthoracic impedance and peak current flow on defibrillation success in a prehospital setting

STUDY OBJECTIVE

To assess whether transthoracic impedance and peak current are determinants of defibrillation success in patients with out-of-hospital ventricular fibrillation (VF).

METHODS

A retrospective cohort study was carried out in a suburban Canadian EMS system. Participants were patients who experienced out-of-hospital cardiac arrest in the regional municipality of Ottawa-Carleton, had VF rhythm at presentation, and received countershocks from the Laerdal Heartstart 2000 automated external defibrillator.

RESULTS

A total of 310 patients met the inclusion criteria. Collectively they received 717 countershocks. The first shocks were successful in converting VF rhythm 25.5% of the time. The most important determinant of shock success was the interval from when the call was received until delivery of the first shock (P<.01). Length of time at scene, current, impedance, and patient age were not significant determinants of success of first shock. The time interval until first shock was also a determinant of survival (P<.01). EMS response time, whether the arrest was witnessed, initial impedance, and current were not determinants of survival.

CONCLUSION

OHCA shock success and survival are associated with EMS system factors such as the interval from when the call was received until delivery of the first shock. The importance of impedance and peak current remain theoretic for out-of-hospital defibrillation success and did not influence defibrillation success in this study.