Final answer:
The voltage needed for a defibrillator to deliver a 10.0-mA current through a 500-ohm resistance, we calculate 5 volts using Ohm's law. The initial range for defibrillation for a child in ventricular fibrillation weighing 20 kg is 40 to 80 joules, based on standard guidelines of 2-4 joules/kg.
Step-by-step explanation:
The question pertains to the use of a defibrillator during cardiac arrest, specifically ventricular fibrillation, and the appropriate voltage to be applied. In open-heart surgery, if a defibrillator needs to deliver a 10.0-mA current through a resistance path of 500 ohms, we use Ohm's law, V=IR, to calculate the required voltage.
The voltage (V) is the product of the current (I, in amperes) and the resistance (R, in ohms).
Therefore, the voltage should be:
V = 10.0 mA × 500 ohms = 0.010 A × 500 ohms = 5 volts.
For a ventricular fibrillation emergency, such as in the scenario described by the student where a child weighs 20 kg and is in cardiac arrest, it is vital to understand that the initial range for defibrillation for children is typically 2-4 joules per kilogram.
Thus, for a 20 kg child, the initial defibrillation dose would range from 40 to 80 joules. However, actual clinical protocols may vary, and during a real-life emergency, healthcare professionals should be guided by the latest resuscitation guidelines or institutional protocols.