Cuff Perforation and Ignition of the New Designed Metal Tracheostomy Tube by Carbon Dioxide Laser Beam : The in Vitro Study

Transcription

1 Cuff Perforation and Ignition of the New Designed Metal Tracheostomy Tube by Carbon Dioxide Laser Beam : The in Vitro Study Sumitra Chowvanayotin M.D.,* Tharnthip Pranootnarabhal M.D.,* Jerasuk Chongkolwatana M.D.** àõ : Õ μ μ ø Õß àõà Õ Õ Ëª å Èπ ËÕ Ÿ ß â«ß å Õπ ÕÕ å Õ å :» πàâõߪø μ ÿ μ «π π æ..,* æ å ª ÿ π æ æ..,* ÿ ß «π æ..** * «««æ» μ å» æ À «À ÿß æœ ** «μ π ß å«æ» μ å» æ À «À ÿß æœ π : ÿà ºŸâ«âª å àõà Õ Õ æ ËÕ ºŸâªÉ«Ë â ºà μ ß πà à«π π â«ß å- Õπ ÕÕ å Õ å Ë Ÿ «à àõà Õ Ë â π ºà μ â«ß Õ å πªí ÿ π «μ ÿª ß å : æ ËÕ Õ μ μ ø Õß cuff Õß àõà Õ Õ Ë â ª å Èπ ËÕ Ÿ ß â«ß å Õπ ÕÕ å Õ å π π å ß â μ ø â μà àõ «àõπ È Á àª Õ π π â : àõ ˪ å Èπ à«ππõ Õß àõà Õ Õ À μ à«π Ë ªìπ Õ Ÿπ Õß Foley catheter ««â â ππõ æ ËÕ ªìπ cuff Õß àõà π Õ «ß àõ π Õ À Ë ª ÕπÀ Õ π πè Õ Ëº methylene blue π«π 5. à â ª π cuff μàõ àõ «ß Ë À ÕßÕÕ π 6 μ μàõπ «π π Õ À 20 πμ μ πè π Webril Ë ÿà πè π 1 x 1.5. âõπ π 2 Èπ«ß «â π cuff â ß å Õπ ÕÕ å - Õ å 10 «μμå π âπºà»ÿπ å ß Õß ß continuous mode ß ª Ë Webril π cuff μ π «μ Èß μà ß ß Õ å π cuff μ ß μ μ ø Õß cuff â«âõß ª º» : à μ ø Õß cuff «μ Õß cuff Õ Ÿà Ë 15 «π ß 95 «π à Ë (mean ± SD) à 57.3 ± 29.1 «π ÿª : àõ ˪ å Èππ Ȫ Õ π â ºŸâªÉ«Ëºà μ â«ß å Õπ ÕÕ å Õ å æ ËÕ «ª Õ «μ «Webril À ß â ß Õ å 15 «π â Àâß «ª Ë π Webril ªìπ Èπ À à Ë ÿ à πè : àõà Õ Õ, å Õπ ÕÕ å Õ å Thai J Anesthesiology 2007 ; 33(4) : * Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University, ** Department of Otolaryngology, Faculty of Medicine, Siriraj Hospital, Mahidol University,

2 Laser surgery is a well-established technique in the treatment of tumors of the upper aerodigestive tract. The most frequently used laser system for this surgery is carbon dioxider laser. When this laser is used in conjunction with an endotracheal tube, there is a risk that laser beam may hit endotracheal tube accidentally and ignite the flammable material of the tube. There are many types of endotracheal tubes designed for laser surgery such as, Norton tube, Laser-flex tube, Laser-Shield II, which are very expensive and the cuffs of these tubes are not laser resistant. 1 To prevent fire, the cuff should be inflated with water or saline solution and covered with pledgets soaked with water. We design the tube to use in the patient who has tracheostomy tube undergoing laser surgery under general anaesthesia by putting the balloon of Foley catheter on the metal tracheostomy tube to be a cuff, inflated with saline solution and use a wet cotton (Webril, The Kendall company, Mansfield, USA.) cover the cuff to prevent perforation and ignition. In this in vitro study, new designed tracheostomy tube was tested with carbon dioxide laser with the power of 10 watts, the beam diameter of 0.25 mm. in the continuous mode was fired directed to the cuff. The duration from the beginning of laser to the cuff perforation was recorded and the ignition of the cuff was observed. Materials and Methods The materials for the testing of the new designed tube are the following lists. 1. Outer tube of metal tracheostomy tube No Foley catheter (Curity, the Kendall company, Mansfield, USA) size F 20 for the tracheostomy tube No. 1-2 and size F 22 for the tracheostomy tube No K-Y jelly to lubricate balloon of Foley catheter to easily put on the tracheostomy tube. 4. The sheath of cotton (Webril, The Kendall Company, Mansfield, U.S.A.) 1 x 1.5 cm. 2 layers (about 1 mm. thickness) to cover the cuff 5. Saline solution to inflated cuff and soaked Webril 6. Stainless steel cylinder with 2 cm. internal diameter which served as a mock trachea 7. Methylene blue The Tube Preparation The Foley catheter was cut 2 mm. from each edge of the balloon, while the inflating port was kept intact (Figure 1) the balloon was lubricated and stretched by a long-nose pliers, then the metal tracheostomy tube Figure 1 The parts of foley catheter used to invented the tube Vol. 33, No. 4, October-December 2007 Thai Journal of Anesthesiology 237

3 was passed through the inner side of this balloon. The proper position of balloon was achieved when the distal end of the balloon was on the distal end of the tracheostomy tube. The inflating port of the balloon was placed on the anterior part of the metal tracheostomy tube to avoid the laser beam. (Figure 2). Methods The carbon dioxide laser (Sharplan 1041S, Sharplan lasers Inc, Israel.) was attached to the operating microscope. The designed tube was inserted into the stainless steel cylinder. A circle circuit anaesthetic system attached to an anaesthesia machine was then connected to the tube via non-cuff endotracheal tube that fit the upper diameter of the tube, 6 litres per minute of oxygen flowed through the tube and into the cylinder for 2 minutes. The cuff of tube was inflated with 5 ml. of methylene blue-coloured saline to seal the cylinder (Figure 3). Adjust the pressure of 20 cm. H 2 O within the tube, cylinder and anaesthetic circuit by adjusting the Figure 2 The invented tube Figure 3 The tube was put in the metal cylinder and connected to anaesthetic machine via non-cuff endotracheal tube 238 «ªï Ë 33 Ë 4 μÿ - π«2550

4 pressure relief valve on the anaesthesia machine. The two layers of normal saline 0.3 ml. soaked Webril 1 x 1.5 cm pledgets placed above the cuff that was protruding from the cylinder. The carbon dioxide laser was set to 10 watts of power in the continuous mode of operation with a beam diameter of 0.25 mm. fired directed at the Webril until the cuff was punctured. The colour changes of Webril from white to blue under microscope will serve as signal that the cuff had been punctured. The time to cuff perforation was recorded and ignition of the cuff was observed. Sample sized (n) 2 calculation From the pilot study, the mean of the time to cuff perforation was 32 sec. SD = 2.55 Confidence level, 1-α or 2 side interval 2 Standard deviation (SD) 2.55 Distance from mean to limit 3.00 n 3 Sample size was 3, that was very small, so we increase the SD. 2 times = 2.55 x 2 = 5.1 Confidence interval, 1-2 α or 2 side interval 2 Standard deviation, SD 5.1 Distance from mean to limit 3.00 n 25 The sample size was 25 Descriptive statistic was used to analyse data. Results There was no ignition of the cuffs. The times to the cuff perforation of 25 tubes were varied from 15 seconds to 95 seconds, the mean ± SD was 57.3 ± 29.1 second. The median was 70 seconds. Discussion Strong and Jako 3 presented their early experience with laser surgery and warned about the possible complication of an airway fire. A survey of otolaryngologists found that airway fires and explosion were the most common serious complications in laser airway surgery. 4 There were several different methods employed to avoid airway fires during anaesthesia and surgery. These include jet ventilation and intermittent or continuous use of one of a variety of endotracheal tubes. 5 There are many tubes designed for laser surgery such as Norton tube, Laser-shield II, and Laser-flex. The Norton tube is a stainless steel, flexible tube, which is unaffected by any laser. It has no cuff, and tracheal seal must be established by packing around the tube with damp surgical sponges, or accepting a large ventilation leakage and compensating for leakage by increasing gas flows. The Laser-Shield II (Xomed-Trease Inc, Jackson Ville, Florida) is a silicon tube with an inner aluminium wrap and an outer teflon coating. The cuff is not laser resistant and contains a blue marker to identify perforation. To prevent fire, the cuff should be inflated with water or saline solution. The laser-flex tube (Mallingckrodt Inc, Pleasantar California) is a stainless steel. It can be used either uncuffed or with two cuffs attached in series. All endotracheal tube cuffs designed for laser procedures are not laser-resistant and there have no ideal designs for all types of laser and all procedures. 1 These endotracheal tubes are more expensive approximately times than polyethylene endotracheal tube and about 4-5 times more than metal tracheostomy tube. Most of the patients with the upper airway problems usually have tracheostomy tube in place. The metal tracheostomy tube is used to prolong and secure airway. To decrease the cost of anesthesia, we design the new tracheostomy tube for the patient who has tracheostomy tube undergoing laser surgery of the upper airway by using outer tube of metal tracheostomy tube attaching with the silicon-coat latex cuff of the Foley catheter (as figure II), fill the cuff with saline to act as a built-in-fire extinguisher and a heat sink. 6,7 Cover the Vol. 33, No. 4, October-December 2007 Thai Journal of Anesthesiology 239

5 cuff with saline soaked Webril to prevent ignition. 8 The most of laser beam powers using in upper airway operation usually set at 4-5 watts, intermittent mode. In this study we evaluated the tube by using an extreme situation, 10 watts, continuous mode. If there is an ignition, the tube should not be used. From the results of the study, the minimum time to perforating of the cuff was 15 seconds and maximum time was 95 seconds, the mean time ± SD was 57.3 ± 29.1 seconds. No ignition of the cuff was found. There was a difference in time to perforation of the cuff may be from the thickness of Foley catheter and the moist of Webrils. We concluded that the designed tube is safe for the use with carbon dioxide laser and we recommend to check the dryness of the Webril after 15 seconds of operation and moisten it if it is found dry. References 1. Jaeger JM. Specialized endotracheal tube. Clin Pul Med 2001 ; 8(1) : Dixon WJ, Massey FJ. Introduction to statistic analysis 4th edition. Mc Graw-Hill ; p Strong MS, Jako GJ. Laser surgery in the larynx : early clinical experience with continuous CO 2 laser. Ann Otol Rhinol Laryngol 1972 ; 81(6) : Fried MP. A Survey of the complication of laser laryngoscopy. Arch Otolaryngol Head and Neck Surg 1984 ; 110(1) : Werkhaven JA. Microlaryngoscopy-airway management with anaesthetic techniques for CO 2 laser. Ped Anesth 2004 ; 14(1) : Sosis MB, Dillon FX. Saline-filled cuffs help prevent laser-induced polyvinylchloride endotracheal tube fires. Anesth Analg 1991 ; 72(2) : LeJeune FE Jr, Grice C, LeTard F, Marice H. Heat sink protection against lasering endotracheal cuffs. Ann Otol Rhinol Laryngol 1982 ; 91(6Pt1) : Sosis MB. Saline-soaked pledgets prevent carbon dioxide laser-induced endotracheal tube cuff ignition. J Clin Anesth 1995 ; 7(5) : «ªï Ë 33 Ë 4 μÿ - π«2550

6 Cuff Perforation and Ignition of the new Designed Metal Tracheostomy tube by Carbon Dioxide Laser Beam : The in Vitro Study Abstract Background : In order to seal the metal tracheotomy tube for anaesthesia during the upper airway laser surgery, we designed the endotracheal tube for a patient with tracheostomy undergoing carbon dioxide (CO 2 ) laser surgery by attachment the balloon of Foley catheter to the distal end of outer tracheostomy tube. Objective : To determine the safety of this tube, ignition and time to perforation of the tube. Method : 25 tubes were investigated. The balloon of each tube was inserted into the proximal end of stainless steel cylinder ; then connected to a circle circuit of anaesthetic machine by non-cuff endotracheal tube, flushed with 6 l/min of oxygen for 2 minutes before cuff inflation. The cuff was then inflated with 5 ml of methylene blue-colour saline and the system pressure was adjusted to 20 cmh 2 O by adjusting the pressure limiting valve on the anaesthesia machine. The pledget of double layers of Webril 1 cm x 1.5 cm, soaked with 0.3 ml normal saline was placed above the cuff. The Sharplan 1041S CO 2 laser was set to 10 watts with a beam diameter of 0.25 mm. fired continuously at the Webril until the cuff was perforated. Result : There were no cuffs ignition reported and time to perforation of the cuff was 57.3 ± 29.1 (mean ± SD) seconds. Conclusion : The new designed tube is safe for use with CO 2 laser with the power up to 10 watts for 15 sec. We recommend to keep the Webril moistened, since they will be combustible if allowed to dry. Keywords : metal tracheostomy tube, carbon dioxide laser surgery Vol. 33, No. 4, October-December 2007 Thai Journal of Anesthesiology 241