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© 2000 International Anesthesia Research Society
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Abstract |
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The esophageal-tracheal Combitube® (ETC; Kendall-Sheridan Catheter Corp., Argyle, NY) is a new device designed for difficult airways and emergency intubation. The manufacturer recommends that the ETC model 37F SA be used in patients with a height of between 122 and 152 cm. The aim of this study was to evaluate whether ventilation is effective and reliable in patients taller than 152 cm by using the ETC 37F SA in the esophageal position. Also, we evaluated whether the airway protection is adequate and whether direct intubation of the trachea with the ETC inserted in the esophagus is possible. We studied 25 anesthetized, paralyzed adult patients, 150 to 180 cm in height. Methylene blue was given orally to all patients before anesthesia induction. Under direct vision, a ETC 37F SA was inserted in the esophagus of all patients. The pharyngeal balloon inflation volume was titrated to air leak and cuff pressures were measured. During surgery, a laryngoscope was inserted into the pharynx with the pharyngeal balloon deflated and the laryngoscopic view was evaluated by using the Cormack-Lehane scale. The presence of methylene blue in the hypopharynx was investigated by direct laryngoscopic vision. Ventilation was effective and reliable in all 25 patients who were 150 to 180 cm in height (average 169 ± 7 cm). In addition, a direct relationship between the pharyngeal balloon volume and patient height was established (P < 0.05), by using linear regression models. The laryngoscopic view of the glottis was adequate to allow direct tracheal intubation. No trace of methylene blue was detected in the hypopharynx. The ETC Model 37F SA may be used in patients from 122 to 185 cm in height. The trachea could be directly intubated with the ETC in the esophageal position in patients with normal airways. The airway protection appears to be adequate.
Implications: The esophageal-tracheal Combitube® Model 37F SA (Kendall-Sheridan Catheter Corp., Argyle, NY) may be used in patients from 122 to 185 cm in height. The trachea could be directly intubated with the Combitube® in esophageal position in patients with normal airways. The airway protection appears to be adequate.
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Introduction |
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The esophageal-tracheal Combitube® (ETC; Kendall-Sheridan Catheter Corp., Argyle, NY), is a plastic, double-lumen tube that enables ventilation independent of its position in the esophagus or the trachea (1). It has been included in the American Society of Anesthesiologists difficult airway algorithm (2), as well as in the guidelines for advanced cardiac life support of the American Heart Association (3), as a suitable alternative airway to endotracheal intubation.
The ETC is a double-lumen, double-cuffed tube (Figure 1). The distal lumen, also referred to as the tracheoesophageal lumen, has an open end. The other lumen, proximal, is also referred to as the pharyngeal lumen (4). A partition wall separates these lumina, and each is linked through short tubes to a connector. The tube of the tracheoesophageal lumen is shorter than that of the pharyngeal to achieve an easier identification. Near the distal end of the ETC, there is a conventional cuff (tracheoesophageal cuff) which can be positioned either in the esophagus or in the trachea, serving to seal these structures. Proximal to this cuff, there are eight perforations along the pharyngeal lumen wall permitting ventilation in case of an esophageal position of the distal end. Proximal to these perforations is a special pharyngeal balloon, designed to be placed between the root of the tongue and the soft palate, sealing the oral and nasal cavities. There are two preferred ways to verify placement of the distal end of the ETC (trachea or esophagus), by capnography or with a self-inflating bulb (5).
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The ETC is available in two sizes: 37F SA (small adult) and 41F. The manufacturer recommends that the SA model be used in patients with a height between 122 and 152 cm and the 41F model in patients taller than 152 cm. Also, the cuffs must be inflated with fixed volumes of air. There are reports of soft tissue damage by using the ETC (6). Wafai et al. (5) titrated the pharyngeal balloon inflation volume to air leak and reported lesser volumes were required.
We observed that the smaller ETC SA fits taller patients, and speculated that while titrating the cuff volumes to air leak there may be a better adjustment to the patient’s anatomy. Thus, the potential for pharyngeal or laryngeal trauma might be reduced. We performed this study to determine the adequate pharyngeal balloon inflation volume (PBIV) of the ETC 37F SA in patients taller than 152 cm.
In addition, we questioned whether the airway protection of the ETC SA in esophageal position is adequate by using the recommended cuff inflation volume in this taller group of patients. On the other hand, when an ETC SA is in the esophageal position, it sometimes may be necessary to intubate the trachea without previously removing the ETC. To date, only studies using a fiberoptic-guided exchange have been performed (7–9). We tested the use of direct laringoscopy with the ETC in situ for exchanging the tubes.
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Methods |
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With institutional review board approval, 25 consenting ASA physical status I patients scheduled to undergo elective surgical procedures were included in the study. Patients undergoing emergency head and neck, intrathoracic, and intraperitoneal surgical procedures were all excluded. Further exclusion criteria were a history of gastroesophageal disease, drug allergy, drug use (regular medications and illicit drugs), smoking habit, clinical evidence of cardiovascular or respiratory disease, obesity (weight/height index >30), or risk factors for full stomach and regurgitation of gastric content. The Mallampati test, as modified by Samsoon and Young, interincisor gap, and atlanto-occipital joint extension were preoperatively evaluated in each patient. The standard noninvasive intraoperative monitors were utilized in all patients.
In order to identify regurgitation and its path around the tracheoesophageal cuff up to the pharynx, gastric contents were dyed with methylene blue (10,11). While sitting, 10 to 15 min before anesthetic induction all patients swallowed a gelatin capsule containing 10 mg methylene blue with 30 mL of water. The gelatin capsule dissolves in water or pH 1–5 within 5 min turning the gastric contents blue. The presence of methylene blue in the hypopharynx was evaluated twice by direct laryngoscopy: first, before intubation and after extubation; and second, while the patient was awake with light anesthesia.
We used the Cormack-Lehane scale (12) to evaluate whether direct tracheal intubation could be performed with the ETC in the esophageal position. This scale evaluates the anatomic features visualized during performance of direct laryngoscopy and quantifies intubation, grading from class I (easy intubation) to class IV (difficult intubation). According to this procedure, done in the middle of surgery, the pharyngeal balloon was deflated and a laryngoscope was introduced between the ETC SA and the tongue while trying to visualize the glottic structures.
After the 10 to 15 min that the methylene blue capsule was swallowed, 1.5 µg/kg fentanyl was given IV and anesthesia was induced by giving 2 mg/kg propofol IV. This was followed by 0.5 mg/kg atracurium, to facilitate laryngoscopy and to avoid any movement or muscle contraction that could interfere with ETC SA insertion or could produce soft tissue damage. Anesthesia was maintained with desflurane in oxygen 100% 1 L/min, 1.5 minimum alveolar anesthetic concentration.
After achieving adequate neuromuscular block (i.e., 1 train-of-four [TOF] response or less), laryngoscopy was performed, and a ETC 37F SA was introduced orally into the esophagus under direct vision. The ETC SA was advanced until the printed ring marks were at the level of the teeth, or until a resistance was felt. The tracheoesophageal cuff was inflated with the recommended 12 mL of air. Then, the pharyngeal balloon was inflated starting with 50 mL of air and titrated to air leak at 20 cm H2O of peak inspiratory pressure during mechanical ventilation (VT 10 mL/kg, RR 10 cycles/min, I:E ratio 1:2). Ventilation was performed via the pharyngeal lumen leading to the pharyngeal perforations.
After surgery, neuromuscular block was reversed with neostigmine (0.06 mg/kg IV); the TOF ratio was >70% in all patients. One anesthesiologist (RMU) performed all intubations and recorded the observations. Statistical analysis was performed by using linear regression models (STATA software version 5.0; Stata Corporation, College Station, TX). Significance was taken as P < 0.05. Values are expressed as mean ± SD.
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Results |
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A total of 23 men and two women between 18 and 65 yr (mean 36.8 ± 13.4 yr) were included in the study. Patient height ranged from 150 to 180 cm (mean 169 ± 7 cm) and mean preoperative fasting time was 12.2 ± 2.6 h. All patients had normal airways. The types of surgical procedures are listed in Table 1. Mean surgical time was 57 ± 24 min (range, 15–110 min). Mean anesthesia time was 73 ± 27 min (range, 20–130 min).
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The ETC SA was easily inserted in all patients by using the laryngoscope. However, four patients (16%) required a second attempt because of either a stop with pharyngeal structures, the neck was too hyperextended with altered palate-pharyngeal curve, the laryngoscope light suddenly failed, or the ETC SA was pushed back when the tracheoesophageal cuff was first inflated (1). The ETC SA was introduced until the teeth were at the level of the two ring marks in 24 patients (96%). In one patient (4%) the ETC SA was introduced 1 cm below that level.
In 19 patients (76%), an air leak with an initial 50 mL of air was detected. Air leak disappeared by increasing the volume of the pharyngeal balloon in 11 patients (44%), and with repositioning of the ETC in the other eight patients (32%). In one patient (4%) no air leak was observed with the initial 50 mL of air and the best seal was obtained with 40 mL (woman patients, height 150 cm). In the other five patients (20%), a complete seal was achieved with the initial volume. This air leak never compromised the quality of ventilation.
The volume of air required to prevent an air leak around the pharyngeal balloon varied between 40 and 85 mL. By using models of linear regression, a direct relationship between the PBIV (mL) and patient height (PH, in cm) was established (Fig. 2). This relationship is expressed as PBIV = (1.0611 x PH) - 112.7; with 95% confidence intervals for the slope from 0.53 to 1.6; R = 0.65 (P = 0.0004).
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Ventilation was accomplished easily in all patients. The maximal peak inspiratory airway pressure ranged from 15 to 30 cm H2O (mean 22 ± 4 cm H2O). None of the patients showed clinical signs of gastric insufflation. Pulse oximeter readings were always
98%, and the capnographic waveforms were regular. The mean ETCO2 values with mechanical ventilation were 32 ± 3 mm Hg and with spontaneous ventilation with the ETC SA in situ, were 42 ± 6 mm Hg. Although not recorded, inflation of the pharyngeal balloon resulted in tongue protrusion in some patients. No change in tongue color could be noted after using the reduced volume in the pharyngeal balloon. There was no trace of methylene blue in the hypopharynx with the ETC SA before insertion, during laryngoscopy, and after removal. In one patient (4%), the distal end of the ETC SA was intensely blue after removal, and at the awake laryngoscopy there was only a thin layer at the bottom of the hypopharynx and nothing up to that point, including the glottis and trachea. No complication was detected in that patient.
The laryngoscopic grade (Cormack-Lehane scale) was I in 18 patients (72%) and II in seven patients (28%); all considered easy endotracheal intubations. In some cases, the pharyngeal cuff partially covered the glottis. This situation was considered as laryngoscopic grade II. Flattening the balloon with a Magill forceps solved this problem. Endotracheal intubation was not performed in any case.
Hemodynamic changes observed and attributed to insertion and extubation of the ETC did not significantly differ from basal values. There was no macroscopic sign of soft tissue damage in 21 patients (84%). In the other four (16%), the following was observed: suffusion at the uvula and other small suffusions at the epiglottis border; a small amount of blood at the hypopharynx below the soft palate, and at the uvula; a small erosion at the uvula; and a small amount of blood emerging from a tooth base.
After ETC SA withdrawal, no patient suffered from nausea, vomiting, cough, or other signs suggestive of airway or pharyngeal irritation. A mild sore throat was reported by four patients (16%) lasting <1 h in three patients and up to 6 h in another. Two of these patients (8%) had pharyngeal lesions, the other two had none.
No patient reported dysphagia or airway or ventilatory problems. At the moment of definitive discharge (5 to 48 h, mean 27 ± 11 h), no patient had pharyngeal symptoms or swallowing difficulties. None of the patients suffered a serious complication from the procedure and none required any treatment.
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Discussion |
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The American Society of Anesthesiologists and the American Heart Association (2,3) have recommended the ETC as a suitable noninvasive artificial airway in failed endotracheal intubation. This is especially valid in emergency and full-stomach patients, in whom other noninvasive alternatives are contraindicated.
Recently, Walz et al. (13) reported the use of the ETC 37F SA in patients up to 198 cm in height. An additional 25 to 50 mL of air was needed to inflate the pharyngeal balloon in some patients, presumably the taller ones. Unfortunately, the authors were not able to report the incidence of lesions and symptoms related to the technique. They recommend the use of the ETC 37F SA independent of an upper limit of height.
Our findings suggest that the smaller ETC 37F SA could be used effectively in patients taller than recommended (>152 cm). In addition, the linear relationship observed between the pharyngeal balloon inflation volume and patient’s height suggests an upper limit of 185 cm. This relationship, when validated, would also help to calculate the appropriate inflation volume needed for each patient. These hypotheses would imply that the ETC 37F SA would be appropriate for patients of 122 to 185 cm (4 to 6 feet) in height and that the ETC 41F should be used in taller patients (>185 cm). We think that the ETC 37F SA would need greater cuff inflation volume in patients taller than 185 cm (>6 feet), leading to cuff overinflation, potential increase in soft tissue damage, possible permanent air leak, and inadequate airway protection. Further studies are needed to investigate these hypotheses.
Reports of lesions with the 37F model have not been published. By titrating only the PBIV volume, we observed some lesions related to the pharyngeal balloon and no lesions related to the tracheoesophageal cuff. As the tracheoesophageal cuff is a high volume, low pressure cuff and the pharyngeal balloon is made of a thicker rubber, it appears that only this balloon volume would be clinically important to potential soft tissue damage. On the other hand, other factors of soft tissue damage and postoperative pharyngeal symptoms, such as insufficient training in its use, careless insertion, a forceful laryngoscopy, and cuff overinflation, should be considered (14,15). We agree with Krafft et al. (16) that the use of the ETC 37F SA inserted under direct vision and adequate depth of anesthesia, including muscle relaxants, would lower the incidence of soft tissue damage. The regular assessment of both cuff pressures appears indicated for intraoperative airway management by using the ETC.
We observed the ETC distal end dyed with methylene blue in one case. We did not find methylene blue around the tracheoesophageal cuff, the hypopharynx, nor the trachea. This patient had no history of gastroesophageal reflux, and he was not studied subsequently for reflux. Thus, based on this and the observations of Deroy and Ghoris (17), it appears that airway protection is adequate.
Exchange of an ETC with an endotracheal tube in the esophageal position could be directly performed in patients with normal airways by deflating the pharyngeal balloon and inserting the endotracheal tube around the ETC. This observation may be important because the ETC is often inserted blindly in some emergency patients with normal airways in whom the ETC lies in the esophageal position >96% (failed intubation in a patient lying on the ground or a patient trapped sitting inside a car). Later, when tracheal intubation is needed, removing the ETC from the esophageal position would not be advisable because of the risk of a full stomach. Thus, tracheal intubation should be performed with the ETC in situ. When a fiberoptic device is not available, or if the operator is not skilled with its use, the described maneuver might be useful. Of course, when the indication for ETC use is a failed intubation because of an abnormal airway, the use of a fiberscope is the best choice.
Unfortunately, for ethical reasons we only treated patients with normal airways. It is necessary to perform further studies to evaluate the ETC 37F SA in patients with abnormal airways. In our study, the unique symptom was mild sore throat that was transient in all cases. As in the Gaitini et al. article (8), a sore throat occurs more frequently than expected with the use of the ETC alone as the result of the manipulations with the laryngoscope during and after surgery.
In conclusion, the ETC SA proved to be a feasible airway management device in this elective group of surgical patients taller than 150 cm. We suggest that the ETC 37F SA be used in patients from 122 to 185 cm (4 to 6 feet), and the ETC 41F in those taller than 185 cm (>6 feet). The use of a laryngoscope during insertion, under adequate depth of anesthesia and with the titration of pharyngeal cuff volume to air leak, could reduce soft tissue trauma. Although airway protection appears adequate, it should not be used electively in anyone who may have a full stomach. The ETC is approved for difficult airway management, and its use has been easy, safe, and reliable. Thus, it should be used occasionally in elective cases so that anesthesiologists feel comfortable with it.
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Acknowledgments |
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Supported, in part, by grants from Kendall-Chile, Zeneca Pharmaceuticals-Chile, and Glaxo-Wellcome Pharmaceutical-Chile. The Combitube® used in this study were provided by Kendall-Chile. Zeneca Pharmaceuticals-Chile provided propofol (Diprivan) and desflurane (Suprane) and the TEC6 vaporizer. Atracurium besilate (Tracrium) was provided by Glaxo-Wellcome Pharmaceutical-Chile. The capsules of methylene blue were prepared at the University of Chile Hospital by Paz Latorre, PharmD.
The authors wish to thank Dr. José Miguel Montes, Dr. César Cárcamo Q., and Dr. Peter Krafft for their invaluable help in reviewing the manuscript.
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Footnotes |
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Presented, in part, as a poster at the XXVI Chilean Congress of Anesthesiology, Valdivia, Chile, November 6–7, 1998.
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References |
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- Frass M. The Combitube: esophageal/tracheal double lumen airway. In: Benumof , Jonathan L, ed. Airway management-principles and practice. St. Louis:Mosby, 1996;444–54.
- Practice guidelines for management of the difficult airway. a report by the ASA Task Force on Management of the Difficult Airway. Anesthesiology 1993;78:597–602.[Web of Science][Medline]
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Kloeck W, Cummins RO, Chamberlain D, et al. The universal advanced life support algorithm. an advisory statements from the Advanced Life Support Working Group of the International Liaison Committee on Resuscitation. Circulation 1997;95:2180–2.
[Free Full Text] -
Urtubia RM, Aguila CM. Combitube: A new proposal for a confusing nomenclature. Anesth Analg 1999;89:803.
[Free Full Text] - Wafai Y, Salem MR, Baraka A, et al. Effectiveness of the self-inflating bulb for verification of proper placement of the esophageal tracheal Combitube. Anesth Analg 1995;80:122–6.[Abstract]
- Mercer MH, Gabbott DA. The influence of neck position on ventilation using the Combitube airway. Anaesthesia 1998;53:146–50.[Web of Science][Medline]
- Ovassapian A, Liu S, Krejcie T. Fiberoptic tracheal intubation with Combitube in place. Analg 1993;76:S315.
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Gaitini LA, Vaida SJ, Somri M, et al. Fiberoptic-guided airway exchange of the esophageal-tracheal Combitube in spontaneously breathing versus mechanically ventilated patients. Anesth Analg 1999;88:193–6.
[Abstract/Free Full Text] - Krafft P, Röggla M, Fridrich P, et al. Bronchoscopy via a redesigned Combitube in the esophageal position. a clinical evaluation. Anesthesiology 1997;86:1041–5.[Web of Science][Medline]
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Blitt CD, Gutman HL, Cohen DD, et al. Silent regurgitation and aspiration during general anesthesia. Anesth Analg 1970;49:707–13.
[Free Full Text] - Bapat PP, Verghese Ch. Laryngeal mask airway and the incidence of regurgitation during gynecological laparoscopies. Anesth Analg 1997;85:139–43.[Abstract]
- Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984;39:1105–11.[Web of Science][Medline]
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Walz R, Davis Sh, Panning B. Is the Combitube a useful emergency airway device for anesthesiologists? Anesth Analg 1999;88:233.
[Free Full Text] - Klein H, Williamson M, Sue-Ling HM, et al. Esophageal rupture associated with the use of the Combitube. Anesth Analg 1997;85:937–9.[Web of Science][Medline]
- Vézina D, Lessard MR, Bussières J, et al. Complications associated with the use of the esophageal-tracheal Combitube. Anaesth 1998;45:76–80.
- Krafft P, Nikolic A, Frass M. Esophageal rupture associated with the use of the Combitube. Anesth Analg 1998;87:1457.
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Deroy R, Ghoris M. The Combitube elective anesthetic airway management in a patient with cervical spine fracture. Anesth Analg 1998;87:1441–2.
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