Experimental Studies to Design Safe External Pediatric Paddles for a DC Defibrillator

Pediatric defibrillator paddles for infants and small children have been designed for a dc defibrillator. Studies in dogs, in which paddles ranging from 3 to 9 cm in diameter were used, suggested that 5-cm paddles were optimal from the standpoint of minimal myocardial damage, skin burns, and deviation of the delivered energy from that shown by the meter of the defibrillator. Transthoracic resistance was found to be inversely related to paddle diameter according to the equation R =(450/d) -7.32, where R represents the transthoracic resistance in ohms and d represents the diameter of paddles in cm. The effect of paddle size on the peak transthoracic voltage, current, and total delivered energy is presented. Use of paddles smaller than 5 cm was associated with discharge of damagingly high voltage and current densities. The effectiveness and relative safety of the 5-cm pediatric paddle are discussed. Even though conclusions reached relative to an optimal paddle size for small patients should be restricted to the dc defibrillator used in these studies, the reported general technique and design procedure should have general applicability in the design of pediatric paddles for other types of defibrillators.