What happens when tissue resistance increases during diathermy?

What happens when tissue resistance increases during diathermy?

• A. Increase in heating
• B. Decrease in heating
• C. No change in heating
• D. Immediate cooling of tissue increase

Answer: (A)

In diathermy, heat is generated when electrical energy is dissipated as heat in the tissue due to its electrical resistance. The power converted to heat follows the relation P = I^2R, where I is the current and R is tissue resistance. If the device maintains a current, increasing tissue resistance raises P, so more energy becomes heat. In practice, tissues with higher impedance (like fat) tend to heat more under diathermy at the same current, illustrating this dependence. Therefore, when tissue resistance increases, heating increases. Immediate cooling or no change would not align with the way resistive heating works in this modality, and a decrease in heating would only occur if the current were kept constant and the device didn’t compensate, which isn’t the typical behavior in standard diathermy delivery.

In diathermy, heat is generated when electrical energy is dissipated as heat in the tissue due to its electrical resistance. The power converted to heat follows the relation P = I^2R, where I is the current and R is tissue resistance. If the device maintains a current, increasing tissue resistance raises P, so more energy becomes heat. In practice, tissues with higher impedance (like fat) tend to heat more under diathermy at the same current, illustrating this dependence. Therefore, when tissue resistance increases, heating increases. Immediate cooling or no change would not align with the way resistive heating works in this modality, and a decrease in heating would only occur if the current were kept constant and the device didn’t compensate, which isn’t the typical behavior in standard diathermy delivery.