Electrosurgical units – how they work and how to use them safely

Compliance monitoring by eye care team • Ensure children wear their spectacles Refer children with complex refractive error and other eye conditions Electrosurgery is used routinely in eye surgery to cut, coagulate, dissect, fulgurate, ablate and shrink tissue. High frequency (100 kilohertz to 5 megahertz), alternating electric current at various voltages (200–10,000 Volts) is passed through tissue to generate heat. An electrosurgical unit (ESU) consists of a generator and a handpiece with one or more electrodes. The device is controlled using a switch on the handpiece or a foot switch. Electrosurgical generators can produce a variety of electrical waveforms. As these waveforms change, so do the corresponding tissue effects. In bipolar electrosurgery (Figure 1), both the active electrode and return electrode functions are performed at the site of surgery. The two tips of the forceps perform the active and return electrode functions. Only the tissue grasped in the forceps is included in the electrical circuit. Because the return function is performed by one tip of the forceps, no patient return electrode is needed. Bipolar electrosurgery operates regardless of the medium in which it is used, permitting coagulation in a fluid environment – a great advantage when attempting to coagulate in a wet field. As a result, bipolar electrosurgery is often referred to as ‘wet field’ cautery. In monopolar electrosurgery (Figure 2), the active electrode is placed at the surgical site. The patient return electrode (also known as a ‘dispersive Electrosurgical units – how they work and how to use them safely