Anesthetic Management of Radiofrequency Ablation of Mediastinal Metastatic Lymph Nodes Adjacent to the Trachea

Abstract

To the Editor: Radiofrequency ablation (RFA) can be applied to percutaneously accessed areas in patients formerly diagnosed as inoperable (1,2). However, RFA can hyperelevate both local temperature and core body temperature because of the thermal conduction from the ablation site (3). We report the management of anesthesia during RFA of mediastinal metastatic lymph nodes adjacent to the trachea. This study of eight male patients (mean age, 58 yr) was approved by our IRB and all patients gave their informed consent. Diagnosed mainly with esophageal cancer, they underwent RFA of mediastinal metastatic lymph nodes. We induced and maintained anesthesia with propofol (2–4 μg/mL) and fentanyl. To prevent irreversible thermal damage to the tracheal mucosa, we preoperatively attached the temperature sensor (Mon-a-therm™, Mallinckrodt Medical, St. Louis, MO) to the inflated cuff of the endotracheal tube with transparent dressing (Tegaderm™, 3M St. Paul, MN) (Fig. 1). After tracheal intubation, we examined the position of the sensor and repeatedly adjusted it, according to real-time computer tomography images, so that we could locate the sensor facing the ablation site (Fig. 2). During ablation, the local temperature at the trachea rose rapidly. We inserted 10 mL of chilled saline, instead of air, into the cuff and exchanged repeatedly, thus preventing a temperature increase in the tracheal mucosa. (Fig. 3). At the time of extubation, we carefully observed the area with a bronchofibroscope and found no complications, such as redness, swelling, bleeding, and perforation.Figure 1.: Small temperature sensor was attached at the inflated cuff of the endotracheal tube with transparent dressing.Figure 2.: Image of real-time computer tomography shows the temperature sensor attached to the cuff of the endotracheal tube (arrow), facing metastatic lymph nodes (LN).Figure 3.: Time course of local tracheal temperature during ablation. With a repeated cooling technique using chilled saline, the temperature was kept below 37°C throughout ablation.Motohiko Hanazaki, MD, PhD Naoyuki Taga, MD, PhD Hideki Nakatsuka, MD, PhD Masataka Yokoyama, MD, PhD Kiyoshi Morita, MD, PhD Department of Anesthesiology and Resuscitology [email protected] Yasuhiro Shirakawa, MD, PhD Tomoki Yamatsuji, MD, PhD Yoshio Naomoto, MD, PhD Department of Gastroenterological Surgery, Transplant, and Surgical Oncology Takao Hiraki, MD, PhD Department of Radiology Okayama University Medical School Okayama, Japan