Accidental Shock Research Articles

Dangers of defibrillation: Injuries to emergency personnel during patient resuscitation

There have been no studies of the nature of defibrillatory shocks or risks to persons, providing them other than one individual case report and a number of incidental accounts. In this study, the severity and nature of injuries to prehospital emergency personnel in King County, Washington are reported. In addition, the types of injuries occurring to defibrillator operators throughout the United States, as voluntarily reported to the Food and Drug Administration (FDA), are described. In King County, prehospital emergency personnel reported eight accidental shocks. One individual was admitted to the hospital for 3 days and required lidocaine for premature ventricular contractions. Most injuries were the result of accidental contact with the patient rather than equipment failure, but the most serious case was caused by equipment failure. There were 13 injuries reported to the FDA over a 3 1/2-year period, and most injuries involved a mild shock or burn. Three patients were admitted to the hospital for observation. Two cases involved equipment failure. The rate of injury for paramedics was 1 per 1,700 defibrillatory shocks, and the rate of injury for emergency medical technician-defibrillator personnel was 1 per 1,000 defibrillatory shocks. These rates probably overestimate the real risk. Emphasis on safety and incorporation of safety procedures into resuscitation protocols can make the rate of injury even lower.

Low-level shock reaction thresholds in high explosives and propellants

Using an underwater aquarium technique, we have measured burn reaction thresholds in a number of explosives and high-energy propellants. The propellants display higher thresholds for burning than the explosives, while the plastic bonded explosives exhibited the highest thresholds among the explosives. The results suggest that the more rubbery explosive compositions are more resistant to initiation of a burn event when subjected to an accidental shock.

Radionuclide evaluation of cardiac trauma

Radionuclides were first used in the evaluation of myocardial trauma as a noninvasive means to detect hemopericardium. At present an important use is in the diagnosis of myocardial contusion, which can be difficult to recognize clinically, and often has nonspecific EKG and enzyme alterations. Technetium-99m pyrophosphate scintigraphy has been shown to be of significant value in confirming this diagnosis. Myocardial scintigrams are helpful in determining the degree of damage produced by penetrating wounds of the heart and can also detect electrical injury to the heart from accidental shock or cardioversion. In addition, multiple gated blood pool scans can determine the hemodynamic significance of mycardial trauma and evaluate for late sequelae such as aneurysm formation.

Accidental “cranial” defibrillation

A case of accidental shock to the head, caused by a cardiac defibrillator, is presented. The shock resulted in minor burns and symptoms similar to those of postelectro-convulsive shock therapy (ECT). A physician participating in an advanced life support course, and familiar with the equipment, was the victim. An assumption that the demonstration equipment was not real seems to have been the cause of the accident. Suggestions for prevention of further episodes are discussed.

Current-limiting resistor for polarizing batteries.

The addition of a current limiting resistor to the high‐voltage polarizing batteries of an ionization chamber is described to reduce accidental shock to personnel and possible equipment damage.

Elimination of the Accidental Punishment of Operant Shock Escape Responses

Commercial shock-generators are frequently used as components in escape-avoidance operant conditioning apparatus. These devices are constructed in such a way that shock is inadvertently transmitted to the manipulandum (and to the wall of the experimental chamber housing i t ) because one pole of the shock circuit is grounded. When S performs a bar-press in the presence of foot shock, as in the escape response, shock not only is transmitted to S's feet through the floor grid but is present at the bar when the response is made. The shock circuit is completed by S's contact with the bar. This accidental shock associated with the manipulandum is undesirable in most shockescape experiments because S is presented with a momentary punishment for the performance of the conditioned response. In general it seems unwise to permit the bar-press to become aversive. The manipulandum-grounding feature of the shock-generating apparatus may be eliminated by the use of a non-conductive manipulandum or by the following modification of the shock-generating apparatus. This modification electrically isolates the shock circuit from the metallic parts of the experimental chamber. One pole of rhe transformer is normally connected to ground at point ( a ) in Fig. 1 while one set of grids is connected to ground at point ( b ) for unscrambled shock or

Direct-Current Generators for Electrostatic Precipitation

IN the English Electric Co.'s Journal for October, a description is given of the high-pressure D.C. dynamos it constructs for use in electrostatic precipitation plant. The Whessoe Foundry and Engineering Co., Ltd., specialises in apparatus for fog and mist extraction, and the English Electric Co.'s dynamos are specially designed to work with its plant. The removal of suspended particles from large volumes of gas is an important commercial problem at the present time. Electrostatic precipitation is now regarded as the most efficient and economical method for cleaning gases. The English Electric Co. has designed many high-pressure D.C. machines for radio transmission purposes, and the new dynamos are based on the experience gained in radio work. The generating unit for a typical equipment has to supply a current of about 0.15 amperes at a pressure of 45 kilovolts. The unit consists of a driving motor made to suit the local supply, coupled to three generators connected in series. The frames of the machines are insulated from the earth by individual supports of solid porcelain. The whole of the high-pressure apparatus is enclosed by screens which separate it from the driving motor and prevent unauthorised access. A simple interlock on the door renders it impossible for anyone to enter the high-pressure compartment when the generators are running. As a further precaution, every conductor which is at high pressure when the machine is running is connected with the earth when the set is at ‘standstill’. Accidental shocks are thus avoided. A notable feature of the set is its ability to withstand a short circuit without a ‘flash-over’. A model precipitation equipment was shown in action at the English Electric Co.'s exhibition last November.

XIX. Description of an improved apparatus for performing electrical experiments, in which the electrical power is increased, the operator intirely secured from receiving any any accidental shocks, and the whole rendered more convenient for experiments than heretofore

1. The first method of improvement consists in lining the inside of the glass cylinder or globe with the following composition.