Carinal hook wrapped in curvature maneuver: An easy insertion technique for Carlens endobronchial catheter intubation

Carinal Hook Wrapped in Curvature Maneuver: An Easy Insertion Technique for Carlens Endobronchial Catheter Intubation To the Editor The Carlens double-lumen, left-sided endobronchial catheter, which was designed for differential bronchial spirometry,1 became a routine method of intubation for one-lung ventilation in intrathoracic surgery.2-4 This double-lumen tube (DLT) has a carinal hook just below the tracheal tube opening directed in the opposite direction to this bronchial tube. It prevents the DLT from being placed too far inside the left bronchus. Special attention is required to the hook during DLT placement. In the classic description of its insertion method, the bronchial tube is first negotiated beyond the vocal cord under direct laryngoscopy. Then the tube is turned 180° counterclockwise to bring the hook anterior and pass it beyond the vocal cords under vision. Once the hook has passed the cords, the tube is rotated 90° clockwise to bring the bronchial tube leftward and the hook rightward.5,6 Then the DLT is pushed down until the hook hinges on the carina. We have evolved a new easier Carlens endobronchial catheter insertion technique. The polyvinyl endobronchial double-lumen tubes (left bronchial with carina hook) (Portex Ltd, Kent, England) are disposable DLTs. These tubes are available in 3 sizes: 5F, 5.5F, or 6F. They consist of 2 side-by-side placed tubes of the same diameter (long bronchial on left side and shorter tracheal on right side) (Fig 1). The bronchial tube comes with a stylet to maintain its leftward curvature. The carinal hook is placed just below the tracheal tube opening, pointing opposite the bronchial tube (Fig 1A). We observed that if the end of the stylet is placed just inside the bronchial tube bevel, we could rotate the tracheal tube anteriorly and over the bronchial tube. In this changed anteroposterior relationship of the 2 tubes, the carinal hook gets wrapped inside the anterior concave curvature of the bronchial tube (Figs 1B and 2). After induction of anesthesia and muscle relaxation, under direct laryngoscopy, the Carlens catheter in its modified position with the J-shaped curvature and flattened carinal hook is passed until the hook has negotiated the vocal cords. The stylet is turned 90° counterclockwise or leftward, and the tracheal tube is untwisted rightward. This simple rotation of the 2 tubes restores the side-to-side relationship of the 2 tubes with the carinal hook pointing opposite the bronchial tube curvature (Fig 3). Then the DLT is advanced inside the trachea until the hook impinges on the carina. Bronchial positioning is confirmed clinically by auscultation of breath sounds only on the left side when the bronchial cuff is inflated and bilateral entry when the tracheal cuff is inflated. This position should be contained by fiberoptic bronchoscopy. We have performed 19 endobronchial intubations during thoracic surgery in adult patients (age 24 to 58 years old; 11 men and 8 women), and the early experience is satisfactory in terms of quick insertion (mean 28 ⫾ 12 second, range, 18 to 90 seconds) and correct placement in most (16 [84.2%]) of the patients on the first attempt. Boucek et al7 showed that insertion of the polyvinyl DLT required 88 ⫾ 91 seconds when passed by the traditional blind approach, and with direct bronchoscopic approach insertion required 181 ⫾ 193 seconds.7 Both methods resulted in successful left main bronchus placement in most patients.8 Operator experience with both methods increases the likelihood of success. Malpositioning of polyvinylchloride tubes too deep after clinical confirmation of tube placement was the most common finding in the study by Cohen et al.9 Carlens-type polyvinylchloride catheters designed with the carinal hook can significantly prevent this problem by not allowing too deep placement of the polyvinyl double-lumen tube. The hook present on the Carlens tube needs special attention during its insertion, however. Complex techniques, such as cutting off the hook10 and tying it closely to the tube by thread with a slip-knot and untying it once it is inside the larynx,11 have been devised. In the classic method of Carlens tube insertion, a good view of the glottis is important to positioning the hook under direct vision, and it requires multiple rotatory movements to safely negotiate the cords. With this insertion method, the distinct advantage is that a significant rotation of the Carlens tube is not needed inside the trachea. A simple rotation of the stylet counterclockwise by 90° and untwisting of the tracheal tube rightward unfurls the hook in its normal position. Because the hook becomes part of the inner curvature of the bronchial tube, it cannot cause any trauma to the vocal cords or arytenoid folds. It can be safely used with a poor laryngoscopic view (ie, without visualizing the cords). Encouraged

Fig 1. (A) Carlens bronchial tube showing normal side-to-side relationship of bronchial tube, tracheal tube, and carinal hook. (B) Stylet fixed at the bevel of bronchial tube and tracheal tube rotated anteriorly gets wrapped inside the bronchial tube curvature.

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Journal of Cardiothoracic and Vascular Anesthesia, Vol 15, No 1 (February), 2001: pp 142-143

LETTERS TO THE EDITOR

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Fig 2. The Carlens double-lumen catheter in the modified anteroposterior relationship of the 2 tubes and the wrapped carinal hook inside the inner curvature of the tube.

Fig 3. The untwisting of the 2 tubes on side-to-side position unfurls the carinal hook back to its normal position and restores the left bronchial tube curvature to facilitate left-sided tube placement.

by the simplicity and the ease of its insertion, we intend to compare the learning curve of residents with the 2 methods for Carlens double-lumen tube insertion. Mukesh Tripathi, MD Mamta Pandey, MBBS Department of Anaesthesiology and Critical Care Medicine Sanjay Gandhi Post Graduate Institute of Medical Sciences Lucknow, India REFERENCES 1. Carlens E: A new flexible double-lumen catheter for bronchospirometry. J Thorac Surg 18:172, 1949 2. Bjo¨rk VO, Carlens E: The prevention of spread during pulmonary resection by the use of a double-lumen catheter. J Thorac Surg 20:151-157, 1950 3. Bjo¨rk VO, Carlens E, Crafoored C: The open closure of the bronchus and the resection of the carina and of the tracheal wall. J Thorac Surg 23:419, 1952 4. Lewis JW Jr, Serwin JP, Gabriel FS, et al: The utility of a double-lumen tube for one-lung ventilation in a variety of noncardiac thoracic surgical procedures. J Cardiothorac Vasc Anesth 6:705-710, 1992 5. El-Etr AA: Improved technic for insertion of the Carlens catheter. Anesth Analg 43:984, 1969 6. Dorsch JA, Dorsch S: Tracheal tubes, in Understanding Anesthesia Equipment (ed 3). Baltimore, MD, Williams & Wilkins, 1996 7. Boucek CD, Landreneau R, Freeman JA, et al: A comparison of techniques for placement of double-lumen endobronchial tubes. J Clin Anesth 10:557-560, 1998 8. Brodsky JB, Macaio A, Cannon WB, Mark JB: “Blind” placement of plastic left double-lumen tubes. Anaesth Intensive Care 23:583-586, 1995 9. Cohen E, Neustein SM, Goldofsky S, Camunas JL: Incidence of malposition of polyvinylchloride and red rubber left-sided double-lumen tubes and clinical sequelae. J Cardiothorac Vasc Anesth 9:122-127, 1995 10. Bjork VO, Carlens F, Friberg O: Endotrachial anesthesia. Anesthesiology 14:60-72, 1953 11. Burton NA, Watson DC, Brodsky JB, Mark JB: Advantages of a new polyvinylchloride double-lumen tube in thoracic surgery. Ann Thorac Surg 36:78-84, 1983 doi: 10.1053/jcan.2001.20396