Correspondence  |   April 2003
Is It Unethical to Use the Combitube in Elective Surgery Patients?
Author Affiliations & Notes
  • Peter Krafft, M.D.
  • *University of Vienna, Vienna, Austria.
Article Information
Correspondence   |   April 2003
Is It Unethical to Use the Combitube in Elective Surgery Patients?
Anesthesiology 4 2003, Vol.98, 1022. doi:
Anesthesiology 4 2003, Vol.98, 1022. doi:
To the Editor:—
We read with interest the article by Keller et al.  1 entitled “The Influence of Cuff Volume and Anatomic Location on Pharyngeal, Esophageal, and Tracheal Mucosal Pressures with the Esophageal Tracheal Combitube.”
The authors used a cadaver model and healthy volunteers to measure the pressures exerted by the esophageal–tracheal Combitube 37 F SA (ETC; Kendall-Sheridan Catheter Corp., Argyle, NY) on the pharyngeal, esophageal, and tracheal mucosa. To our knowledge, this is the first description of the use of the Combitube in awake volunteers. The very low amount and concentration of local anesthetic used (10 puffs of 1% lidocaine) demonstrate the ease of esophageal insertion of the device, even in awake volunteers. We appreciate the work of the authors but want to comment on several other aspects of their paper.
The authors inflated the oropharyngeal balloon and distal cuff to a maximum volume of 100 and 20 ml, respectively, which is far above the maximum volume recommended by the manufacturer (85 and 12 ml, respectively). The authors observed relatively high mucosal pressures, potentially exceeding mucosal perfusion pressures, and do not recommend the ETC for routine anesthesia cases. However, several recent publications have clearly shown that neither the oropharyngeal balloon nor the distal cuff has to be inflated to the maximum volume recommended, and that much lower volumes are sufficient in the majority of patients.
Hartmann et al.  2 demonstrated that an oropharyngeal balloon inflation volume of 55 ± 13 ml is sufficient in the majority of patients, especially in elective surgery patients. Similar results were obtained by Urtubia et al.  , 3 and even by Keller et al.  1 in the present paper, because a volume of 47 ± 12 ml was enough to reach an oropharyngeal seal pressure of 30 cm H2O. This indicates that the ETC used at low inflation volumes provides an oropharyngeal seal that can never been reached with use of a standard laryngeal mask airway (oropharyngeal leak pressure at maximum inflation, 16 cm H2O [range, 12–19]) or even an LMA-ProSeal™  (Laryngeal Mask Company, San Diego, CA, USA; 27 cm H2O [range, 21–32]). 4 
Therefore, the higher volumes used by Keller et al.  1 are unnecessary, potentially traumatizing, and not recommended by the manufacturer. Moreover, we assume that the incidence of pharyngeal trauma induced by the oropharyngeal balloon is more dependent on inflation velocity than on maximum inflation volume. 2 In experienced hands, the incidence of minor complications like traces of blood on the ETC on removal can be reduced to 27%5 or 10%, 2 and postoperative complaints like dysphagia and sore throat can be reduced to 16% and 8%, respectively. 2,3 
With regard to the cadaver data on tracheal mucosal pressure exerted by the ETC, an ETC inserted into the trachea works like a standard endotracheal tube, and therefore inflation to just-sealing volume and pressure is enough. We inserted the ETC into the trachea of three patients (body weight, 66, 80, and 87 kg) and inflated the cuff to obtain a leak pressure of 30 cm H2O or more. The resulting sealing volumes and intracuff pressures were 4, 5, and 6 ml and 26, 31, and 32 cm H2O, respectively. Therefore, in tracheal position the distal cuff acts as a low-pressure cuff, and inflation to a volume of up to 20 ml (approximately twice as high as recommended) not only is unnecessary but also may even result in severe tracheal damage. Moreover, the ETC almost never blindly enters the trachea in emergency situations.
In conclusion, we are not convinced that the data presented by Keller et al.  1 preclude the use of the Combitube 37 F SA in routine anesthesia. To the contrary, the ETC provides a very good airway seal and aspiration prophylaxis when used properly in the esophageal position. We recommend strict adherence to the manufacturer's guidelines, rather slow inflation of the oropharyngeal balloon, and use of the lowest inflation volumes (mainly in the range of 40–60 ml) to obtain an airtight seal.
Keller C, Brimacombe J, Boehler M, Loeckinger A, Puehringer F: The influence of cuff volume and anatomic location on pharyngeal, esophageal, and tracheal mucosal pressures with the esophageal tracheal Combitube. A nesthesiology 2002; 96: 1074–7Keller, C Brimacombe, J Boehler, M Loeckinger, A Puehringer, F
Hartmann T, Krenn CG, Zoeggeler A, Hoerauf K, Benumof JL, Krafft P: The esophageal-tracheal Combitube Small Adult. Anaesthesia 2000; 55: 670–5Hartmann, T Krenn, CG Zoeggeler, A Hoerauf, K Benumof, JL Krafft, P
Urtubia RM, Aguila CM, Cumsille MA: Combitube: A study for proper use. Anesth Analg 2000; 90: 958–62Urtubia, RM Aguila, CM Cumsille, MA
Keller C, Brimacombe J: Mucosal pressure and oropharyngeal leak pressure with the ProSeal versus laryngeal mask airway in anaesthetized paralysed patients. Br J Anaesth 2000; 85: 262–6Keller, C Brimacombe, J
Gaitini LA, Vaida SJ, Mostafa S, Yanovski B, Croitoru M, Capdevila MD, Sabo E, Ben-David B, Benumof J: The Combitube in elective surgery: A report of 200 cases. A nesthesiology 2001; 94: 79–82Gaitini, LA Vaida, SJ Mostafa, S Yanovski, B Croitoru, M Capdevila, MD Sabo, E Ben-David, B Benumof, J