Electricity-associated injuries I: outdoor management of current-induced casualties

Direct current electrical injuries: A systematic review of case reports and case series

BACKGROUND

Direct current (DC) powered equipment and devices, including photovoltaic systems, high-voltage direct current power lines and novel concepts in electromobility have become increasingly popular in recent years. However, under adverse circumstances by malfunction or mishandling of these applications electrical injuries may occur when electric current passes through the human body. This review aimed at systematically summarizing the medical consequences of DC electrical injuries described in case reports and case series.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guided the methodological conduct and reporting.

RESULTS

Sixteen case reports and 3 case series were eligible for this review and included 70 patients. The reviewed articles were very heterogeneous regarding sources of DC electrical injuries and the reported medical consequences, including burns and skin lesions (n=67), neurological consequences (n=11), unconsciousness (n=10), cardiac consequences (n=8) and bone fractures (n=6). Seventeen individuals did not survive the electrical injuries.

CONCLUSION

From the few available data and partly incomplete documentations of cases we could gather hints of DC medical consequences, however, it was not possible to identify well-defined medical consequences for various circumstances of DC electrical injuries in occupational and non-occupational settings. To achieve this goal, additional studies are required, each providing a comprehensive description of the medical consequences and the circumstances of the electrical injuries.

Performance of an automated external defibrillator during simulated rotor-wing critical care transports

OBJECTIVE

This study aimed to evaluate whether an automated external defibrillator (AED) was accurate enough to analyze the heart rhythm during a simulated rotor wing critical care transport. We hypothesized that AED analysis of the simulated rhythms during a helicopter flight would result in significant errors (i.e., inappropriate shocks, analysis delay).

METHODS

Three commercial AEDs were tested for analyzing the heart rhythm in a helicopter using a manikin and a human volunteer. Ventricular fibrillation (VF), sinus rhythm, and asystole were simulated by using an arrhythmia simulator of the manikin. The intervals from analysis to shock recommendation were collected on a stationary and in-motion helicopter. Sensitivity and specificity of three AEDs were also calculated. Vibration intensities were measured with a digital vibration meter placed on the chest of the manikin/human volunteer both on the stretcher and on the floor of the helicopter.

RESULTS

All AEDs correctly recommended shock delivery for the cardiac rhythms of the manikin. Sensitivity for VF was 100.0% (95% CI 91.2-100.0) and specificity for sinus rhythm and asystole were 100.0% (95% CI 91.2-100.0). Although the recorded ECG rhythms of the volunteer in an in-motion helicopter showed baseline artifacts, all AEDs analyzed the cardiac rhythm of the volunteer correctly and did not recommend shock delivery. On the floor of the helicopter, the median measured vibration intensity was 6.6 m/s(2) (IQR 5.5-7.7 m/s(2)) with significantly less vibrations transmitted to the manikin/human volunteer chest (manikin median 3.1 m/s(2), IQR 2.2-4.0 m/s(2); human volunteer median 0.95 m/s(2), IQR 0.65-1.25 m/s(2)).

CONCLUSION

This study suggested that current AEDs could analyze the heart rhythm correctly during simulated helicopter transport. Further studies using an animal model would be needed before applying to patients.

European first aid guidelines

AIM

Our objectives were to determine the most effective, safe, and feasible first aid (FA) techniques and procedures, and to formulate valid recommendations for training. We focussed on emergencies involving few casualties, where emergency medical services or healthcare professionals are not immediately present at the scene, but are available within a short space of time. Due to time and resource constraints, we limited ourselves to safety, emergency removal, psychosocial FA, traumatology, and poisoning. Cardiopulmonary resuscitation (CPR) was not included because guidelines are already available from the European Resuscitation Council (ERC). The FA guidelines are intended to provide guidance to authors of FA handbooks and those responsible for FA programmes. These guidelines, together with the ERC resuscitation guidelines, will be integrated into a European FA Reference Guide and a European FA Manual.

METHODS

To create these guidelines we used an evidence-based guideline development process, based on the methodology of the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The recommendations cover FA for bleeding, wounds, burns, spinal and head trauma, musculoskeletal trauma, and poisoning, as well as safety and psychosocial FA.

CONCLUSIONS

Where good evidence was available, we were able to turn science into practice. Where evidence was lacking, the recommendations were consensus-based. These guidelines provide systematically developed recommendations and justifications for the procedures and techniques that should be included in FA manuals and training programmes.

Notfallmedizinische Versorgung von Blitz- und Stromschlagverletzungen

The pattern of injuries following electrical accidents and the treatment by emergency teams differ depending on whether exposure was to a low-voltage or high-voltage power source or to a lightning bolt. Tissue damage results from the direct effect of current on cell membranes and from conversion of electrical energy into heat. Depending on the magnitude of electrical energy and the duration of exposure, cardiac dysrhythmia, damage to nerve tissue, extensive burns and shock may occur. Multi-system injury is frequently observed, either directly related to electrical shock or secondary to concurrent trauma. Extrication of victims from the energy field must be performed under strict observance of self-protection measures for the rescuers. In high-voltage incidents the rescuers must wait at a distance until the power supply has been turned off and demonstrably grounded. Analgesia, anxiolysis and administration of crystalloid fluids are needed, especially for injuries from high-voltage power sources. Severe burns of the face and neck call for early intubation and ventilation. Monitoring is performed with pulsoximetry, blood pressure measurement and ECG, giving highest priority to the unconscious patient with cardiac and respiratory arrest. Cardio-pulmonary resuscitation (CPR) follows the international guidelines for resuscitation and may be effective after delayed onset and even after prolonged resuscitation attempts.

Safety aspects for public access defibrillation using automated external defibrillators near high-voltage power lines

BACKGROUND

Automated external defibrillators (AEDs) must combine easy operability and high-quality diagnosis even under unfavorable conditions. This study determined the influence of electromagnetic interference caused by high-voltage power lines with 16.7-Hz alternating current on the quality of AEDs' rhythm analysis.

METHODS

Two AEDs frequently used in Austria were tested near high-voltage power lines (15 kV or 110 kV, alternating current with 16.7 Hz). The defibrillation electrodes were attached either to a proband with true sinus rhythm or to a resuscitation dummy with generated sinus rhythm, ventricular fibrillation, ventricular tachycardia or asystole.

RESULTS

Electromagnetic interference was much more prominent in a human's than in a dummy's electrocardiogram and depended on the position of the electrodes and cables in relation to the power line. Near high-voltage power lines the AEDs showed a significant operational fault. One AED interpreted the interference as a motion artifact, even when underlying rhythms were clearly detectable. The other AED interpreted 16.7-Hz oscillation as ventricular fibrillation with consequent shock advice when no underlying rhythm was detected.

CONCLUSION

The tested AEDs neither filter nor recognize a technical interference of 16.7 Hz caused by 15-kV power lines above railway tracks or 110-kV overland power lines, as run by railway companies in Austria, Germany, Norway, Sweden and Switzerland. These failures in AEDs' algorithms for rhythm analysis may cause substantial harm to patients undergoing public access defibrillation. The proper function of AEDs needs to be reconsidered to guarantee patients' safety near high-voltage power lines.