Effectiveness of Fiberoptic Intubation in Anticipated Difficult Airway

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1 Original Article Effectiveness of Fiberoptic Intubation in Anticipated Difficult Airway Khawaja Kamal Nasir, Faraz Mansoor From Department of Anesthesia, Pakistan Institute of Medical Sciences, Islamabad. Correspondence: Dr Khawaja Kamal Nasir Received: September 14, 2005 Accepted: October 11, 2005 ABSTRACT Objective: The objective of this study was to evaluate the effectiveness of firbreoptic intubation in patients with anticipated difficult airway. Methods: Forty patients of both sexes were included in the study. The patients were informed about the procedure in the preoperative visit. After one mg of midazolam and 0.2 mg of glycopyrrolate, local anesthesia of the upper airway, nasal cavity and trachea was achieved with lignocaine. Xylometazoline nasal spray was used for vasoconstriction of nasal mucosa. After achieving anesthesia of the airway fibreoptic scope was introduced through the nose into the trachea. Endotracheal tube was railroaded over the scope into the trachea. Results: Intubation rate was 100%. The most common complication observed was that of nasal trauma and other minor complications like coughing and gagging or misplacement of the tracheal tube were also observed. Conclusion: Fiberoptic intubation in anticipated difficult airway was found to be safe, effective and highly successful. (Rawal Med J 2005;30:82-84). Key words: Difficult intubation, fiberoptic intubation, regional anesthesia. INTRODUCTION The fundamental responsibility of the anesthetist is to maintain a safe airway. It has been estimated that inability to successfully manage very difficult airway has been responsible for as many as 30% of deaths attributable to anesthesia. 1 The reported incidence of difficult intubation is one in every 65 patients. 2 Fiberoptic bronchoscope and laryngeal mask airway have contributed to a large extent in the management of difficult airway. 3 Unrecognized esophageal intubation is an important and preventable cause of anesthetic mortality and serious morbidity. Direct visual confirmation of the tracheal tube passing into the trachea through the vocal cords confirms correct placement. Whenever tracheal intubation is carried out with the help of fiberoptic bronchoscope larynx and trachea are directly visualized, thus confirming the correct placement of the endotracheal tube. The objective of our study was to evaluate the effectiveness of firbreoptic intubation in patients with anticipated difficult airway.

2 MATERIAL AND METHODS Forty patients of both sexes with the age of 18 years and above were included in the study carried out at the Pakistan Institute of medical sciences, Islamabad. It was approved by the medical ethics committee. An informed consent was taken from all study participants. Patients having anticipated difficult airway such as with huge goiters, intraoral swellings, post-burn neck contractures, post radio-therapy of the neck, arthritic diseases including ankylosing spondylitis, rheumatoid arthritis and decreased movement of temporomandibular joint and cervical spine fractures were included in the study. Patients with nasal trauma, complete upper airway obstruction, sever hypoventilation, profuse upper airway bleeding, basal skull fractures, obstetric patients, emergency surgeries and history of allergy to local anesthetics were excluded. The cause of anticipated difficult airway in these patients is shown in table 1. Table 1. Causes of difficult airway. (N=40) Indications Number Enlarged goiter 10 Laryngeal growth 8 Post-burn contracture 6 Limited mobility at temporo-madibular joint 4 Ankylosing spondylitis 3 Recurrent thyroid 2 Thyroid carcinoma 2 Post radiotherapy neck 2 Congenital hypertrophy of soft palate 1 Rheumatoid arthritis 1 Previous history of failed intubation 1 On arrival in the operating room, intravenous cannula and electrocardiographic leads were placed and continuous monitoring of electrocardiogram, blood pressure and oxygen saturation were done. Glycopyrrolate 0.2 mg and midazolam 1 mg was administered through the intravenous line just before the start of the procedure. Glycopyrrolate was used as antisialogogue and midazolam was used as an anxiolytic. Mouth, pharynx and upper part of the larynx were anesthetized by asking the patient to gargle with 4% lignocaine for four to seven minutes, or when the patient informed of numbness in the throat. Patient s nasal cavity was sprayed with xylometazoline 0.1% to achieve vasoconstriction. Nasal anesthesia was achieved with Lignocaine 4% dipped cotton swabs. In order to achieve full anesthesia of the entire trachea between carina and vocal cords 3 ml of lignocaine 2% were drawn into a 5 ml syringe with a 23 gauge needle. After identifying cricothyroid membrane the syringe was directed posteriorly and perpendicularly to the floor. The position of the needle in the trachea was confirmed by aspirating air through the syringe. Lignocaine 2% solution was injected rapidly and the needle was withdrawn. A fiberoptic bronchoscope (Olympus.MB156) with a suction

3 channel and length of 60cm was used. A 6.5 mm internal diameter endotracheal tube was railroaded over the bronchoscope. Fibreoptic bronchoscope was smoothly inserted through the nose under direct vision into the trachea through the vocal cords. The trachea was identified and endotracheal tube was then railroaded over the fibreoptic bronchoscope to enter trachea, the bronchoscope was then withdrawn. Placement of the endotracheal tube was confirmed visually and later with the help of observing the endtidal Co2 trace on the capnograph. After confirming this, general anesthesia was induced by making use of the appropriate anesthetic agents, analgesics and muscle relaxants. RESULTS There were 37% male and 63% females in the study. All the patients were intubated successfully, making a success rate of 100%. Eleven (27.5%) patients had minor complications (table 2). More than on complication occurred in a single patient at one time. The most common complication observed was mild nasal trauma resulting in bleeding in seven (17.5%) patients. Table 2. Complications of fiberoptic intubation. (N = 40) Complications Number Percentage Nasal trauma % Coughing & gagging % Difficulty 4 10% Desaturation 1 2.5% Esophageal intubation 1 2.5% DICUSSION There are many tests available to anticipate difficult airway on preoperative visit, but none of these is sensitive enough to be effective in its full perspective. 4 We found that the technique of fibreoptic intubation was very effective in patients with anticipated difficult airway due to reduced jaw and neck movements and problems with the airway it self. Alternative techniques are available which include blind nasal, retrograde and light wand assisted intubation. 5 All of these techniques may involve some movement of the cervical spine or general anesthesia. Furthermore, visual confirmation of the placement of the endotracheal tube is not achieved by any of these techniques. A success rate of 93.9% and severe nasal bleeding occurred in 1.3% in a study of 1612 patients. 6 We encountered minor complications in eleven (27.5%) patients. The presence of anatomically difficult airway and any pathological anomaly in the airway makes this job very difficult. 7 Use of lignocaine jelly, can stick to the optic scope and can lead to interference in visibility. Cocaine is a good local anesthetic agent, 8 but toxic reactions have been reported. Lignocaine 4% cotton dipped swabs with oxymetazoline spray for vasoconstriction is safe and does not interfere with the visibility at bronchoscopy. 9

4 Mucous secretions on lens can result in 20% of failure rate. 10 However, in our study, glycopyrrolate was used to dry secretions before the procedure hence secretions posed no problem to the visibility. Difficulty with fiberoptic technique with the use of heavy sedation and general anesthesia 11 was noted and in 2000 Farling recommended awake fiberoptic intubation whenever difficult intubation is anticipated. 12 Although we encountered technical difficulty in fibreoptic intubation in four patients (10%), this was not because of sedation but because of the posterior part of the tongue that had obstructed the view. A simple tongue tug by an assistant was enough to clear the view. In conclusion, we found fiberoptic intubation a safe and reliable procedure devoid of any major complications. Adequate preparation of the patients was the key factor responsible for our high success rate of fiberoptic intubation. It can be accomplished easily with minimal complications provided the anesthetist is adequately trained. REFRENCES 1. Morris IR. Airway management. In: Emergency Medicine: Concepts and Clinical Practice, 3 rd ed, St. Louis: Mosby Year Book, 1992: Hobbs G. Complications during Anesthesia, In Text Book of Anesthesia, 4 th Ed: Harcourt Publishers Limited London, 2001: Albanon-Sofelo R, Atkins JM, Broom RS, et al. Textbook of Advanced cardiac Life Support. American heart Association Butler PJ, Dhara SS. Prediction of difficult laryngoscopy: An assessment of the thyromental distance and Mallampati predictive test. Anesth Intens Care 1992;20: Jenkin K, Wong DT, Carrea R. Management choices for the difficult airways by Anesthesiologists in Canada. Can J Anesth 2002:49: Heidegger T, Gerig HJ, Ulrich B. Structure and process quality illustrated by fibreoptic intubation: analysis of 1612 cases. Anesthesia 2003;58: King TA, Adams AP. Failed tracheal intubation. Br J Anesth 1990;65:

5 8. Tarver CP, Noorily AD, Sakai CS. A comparison of cocaine vs lidocaine with oxymetazoline for use in nasal procedures. Otolaryngol Head Neck Surg 1993;109: Kundra P, Kutrailain S, Ravishankar M. Local anesthesia for awake fiberoptic intubation. Acta anaesthesiol scand 2000;44: Agro F, Cataldo R, Carasiiti M, Costa F. The seeing stylet: A new device for tracheal intubation. Resuscitation 2000;44: Ovassapian A. Fibreoptic assisted management of airway. ASA Annual Refresher Course Lectures 1990;254: Farling PA. Thyroid disease. Br J Anesth 2000;85:15-28.

Difficult Airway. Department of Anesthesiology University of Colorado Health Sciences Center (prepared by Brenda A. Bucklin, M.D.)

Difficult Airway. Department of Anesthesiology University of Colorado Health Sciences Center (prepared by Brenda A. Bucklin, M.D.) Difficult Airway Department of Anesthesiology University of Colorado Health Sciences Center (prepared by Brenda A. Bucklin, M.D.) Objectives Definition & incidence of the difficult airway Evaluation of