General description of procedure, equipment, technique
Initially defined in 1995 and subsequently described in European Respiratory Society (ERS) and American Thoracic Society (ATS) guidelines, interventional pulmonology is “the art and science of medicine as related to the performance of diagnostic and invasive therapeutic procedures that require additional training and expertise beyond that required in a standard pulmonary medicine training program.” Clinical entities encompassed within the discipline include complex airway management, benign and malignant central airway obstruction, pleural diseases, and pulmonary vascular procedures.
Diagnostic and therapeutic procedures pertaining to these areas include rigid bronchoscopy, transbronchial needle aspiration, autofluorescence bronchoscopy, endobronchial ultrasound, transthoracic needle aspiration and biopsy, laser bronchoscopy, endobronchial electrosurgery, argon-plasma coagulation, cryotherapy, airway stent insertion, balloon bronchoplasty and dilatation techniques, endobronchial radiation (brachytherapy), photodynamic therapy, percutaneous dilatational tracheotomy, transtracheal oxygen catheter insertion, medical thoracoscopy, and image-guided thoracic interventions. This presentation focuses on electrosurgery, often erroneously referred to as electrocautery.
Electrosurgery uses alternating current at a high frequency (105 to 107 Hz) to generate heat that coagulates, vaporizes, or cuts tissue, depending on the power setting. In monopolar electrosurgery common to pulmonary medicine, current passes through tissue, entering at a small electrode (the “probe”) and exiting the tissue at a much larger, dispersive electrode (the “pad”). In bipolar electrosurgery, the electrodes are often very close together, and only go through tissue that is directly between the two electrodes, such as with a bipolar forceps to control bleeding vessels during surgery. Bipolar electrosurgery is rarely if ever used in interventional pulmonology, although probes for use in gastroenterology may be adaptable to bronchoscopy.
The power applied by the electrosurgery device (measured in watts) corresponds to the heat generated in the tissue [as related in the equation, Power = (Current)2 X Resistance]. The degree of destruction depends on the applied power, electrical properties of the tissue, device-tissue contact time, and the contact surface area. At a temperature of approximately 70°C, tissue coagulates; over 200°C, tissue carbonizes. Coagulation involves high amperage and low voltage, whereas vaporization uses high voltage and low amperage. When cutting, the tissue actually separates ahead of the probe. If coagulation is also required, blending the cutting setting with coagulation is accomplished in modern electrosurgical units. When a tissue is heated sufficiently, cellular water evaporates, destroying cells. Heating to higher temperatures leads to chemical breakdown of the cell constituents and eventual vaporization or carbonization.
Indications and patient selection
Indications for electrosurgery are similar to those for use of the Nd: YAG laser. Similar to laser therapy, electrosurgery produces rapid debulking of tumor, but at a lower procedure cost. Electrosurgery is an effective method for palliation and is a less expensive alternative than laser therapy.
Contraindications to electrosurgery are similar to those for Nd: YAG laser therapy. In addition, patients with pacemakers and internal defibrillators would not be suitable for monopolar electrosurgery without preparation or deactivation of the device since the current passes through the patient’s body.
Details of how the procedure is performed
Insulated flexible bronchoscopes with working channels of 2.0 mm or greater are used. Electrosurgery blunt-tip probes are compatible with the flexible bronchoscopes that are usually used. The power generator regulates the high-frequency current, and the operator adjusts the settings based on the target tissue and the intention to cut, cut and coagulate, or vaporize.
The operator may use either a closed forceps, the blunt electrosurgery probe, or electrosurgery knife to manipulate the lesion, assess its size, mobility, friability, and bleeding potential, and locate any attachments to the airway. Polypoid lesions may be amenable to use of the snare, which is used to cut and remove tissue. A “blended” current is used to cut and coagulate, but not to vaporize tissue.
Interpretation of results
Performance characteristics of the procedure (applies only to diagnostic procedures)
Outcomes (applies only to therapeutic procedures)
In one reported series, hemoptysis was controlled in 75 percent of cases and dyspnea alleviated in 67 percent; cough or stridor was relieved in 55 percent. In another series, twenty-eight of twenty-nine patients treated had symptomatic improvement following removal of a lesion using a snare. Finally, in one series of seventeen patients, fifteen had immediate restoration of a patent airway, eight had relief of dyspnea, and four had control of hemoptysis.
Alternative and/or additional procedures to consider
Other procedures to consider include Nd:yag laser, argon plasma coagulation, and cryotherapy.
Complications and their management
Endobronchial fires have been reported during the electrosurgery procedure. In the two cases, a high concentration of inspired oxygen was used; in one case, a silicon stent ignited. Several investigators have reported hemorrhage, usually minor. One death secondary to hemorrhage has been reported. Operator and patient burns and electrical shocks are noted in the literature as possible complications; however, published data are scant.
What’s the evidence?
Morris, ML, Tucker, RD, Barob, TH. “Electrosurgery in gastrointestinal endoscopy: principles to practice”. Am J Gastro. vol. 104. 2009. pp. 1563-1574. (Although written for gastroenterologists, this comprehensive review explains many aspects of electrosurgery through endoscopy.)
Homasson, JP. “Endobronchial electrosurgery”. Semin Respir Crit Care Med. vol. 8. 1997. pp. 535-543. (An early report and large review of the use of endobronchial electrosurgery.)
Hooper, RG, Jackson, FN. “Endobronchial electrocautery”. Chest. vol. 87. 1995. pp. 712-714. (An early report on the use of electrocautery in the lung for palliation.)
Lavandier, M, Carre, T, Rivoire, B. “High frequency electrocautery in the management of tracheobronchial disorders”. Respir Crit Care Med. vol. 75. 1996. pp. A477(Report describing the role of palliative endobronchial electrocautery.)
van Boxem, T, Muller, M, Venmans, B. Chest. vol. 116. 1999. pp. 1108-1112. (A study indicating that electrosurgery may be as effective as Nd:YAG laser, but with less cost.)
Sutedja, C, Schramel, PMNH, Smit, HJF. “Bronchoscopic electrocautery as an alternative for Nd: YAG laser in patients with intraluminal tumor”. Eur Resp. vol. 9. 1996. pp. 258-259s. (An analysis that confirms the low cost of electrocautery.)
Sutedja, C, Van Kralingen, K, Schramet, FMNH. “Fiberoptic bronchoscopic electrosurgery under local anesthesia for rapid palliation in patients with central airway malignancies: A preliminary report”. Thorax. vol. 9. 41994. pp. 1243-1246. (Report addressing the feasibility of electrocautery as an outpatient procedure.)
**The original authors for this chapter were Drs. Francis D. Sheski and Praveen N. Mathur. The chapter was revised by Dr. J. Scott Ferguson.
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- General description of procedure, equipment, technique
- Indications and patient selection
- Details of how the procedure is performed
- Interpretation of results
- Performance characteristics of the procedure (applies only to diagnostic procedures)
- Outcomes (applies only to therapeutic procedures)
- Alternative and/or additional procedures to consider
- Complications and their management
- What’s the evidence?