Diathermy
Basis of diathermy
- Electrical current converted to thermal energy
- Amount of heat is proportional to volume of tissue traversed by current (need for broad contact with diathermy pad)
Types of diarthermy
- Monopolar
- Circuit: plate, cable, patient
- Cut (most effective when electrode placed a small distance away from tissue): continous current discharges across air gap, high temperature sparks generated, causes cellular water to explode
- Coagulate: intermittent current released: tissue damage occurs by "fulguration", intermittent bursts of energy generated smaller effects
- Bipolar
- Current transferred between two electrode (tips)
- Safer but only able to coagulate
Key points
- Check position of pad (surgeon's legal responsibility)
- Avoid monopolar diathermy if patient has pacemaker; position plates away from pacemaker
- Avoid diathermy on long pedicles (ie, testis, penis, finger) as current with cause thrombosis of vessel
- Check insulation
- Avoid use in GI surgery - farting causes explosions
