BJA Advance Access originally published online on October 30, 2006
British Journal of Anaesthesia 2007 98(1):141-144; doi:10.1093/bja/ael289
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Difficult laryngoscopy made easy with the use of left-hand laryngoscope blade
Department of Anaesthesia, Christian Medical College Vellore, India
*Corresponding author: Department of Anaesthesia, Christian Medical College, Vellore 632004, India. E-mail: sanjib{at}cmcvellore.ac.in
Accepted for publication September 20, 2006.
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Abstract |
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In scenarios where difficult airway is anticipated as a result of a mass or any pathology in the right side of the upper airway, the plan of approach depends on the extent of difficulty assessed by various airway assessment tests/methods. If significant difficulty is suspected some of the available options include either an awake/sedated fibreoptic or blind nasal intubations. When the airway pathology involves part of the right side or exclusively the whole of the right side compressing the airway towards the left, there is no room to position a normal right or straight blade. A left-hand laryngoscope can be used in these types of cases where anatomy and contour of the blade manoeuvres the tongue and the right-sided lesion, thereby providing an unobstructed left-sided view of the larynx. The left-hand laryngoscope blade has been useful in converting the Cormack and Lehane grade III/IV laryngoscopies to grade II in our cases where the pathology was located exclusively on the right side of the airway. These cases suggest that there may be a role of left-hand laryngoscope in the management of difficult airway, particularly, in cases where there are right-sided mass lesions obstructing the airway.
Keywords: laryngoscopy; left-hand laryngoscope; difficult airway
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Introduction |
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Airway management has always been a vital skill in the practice of anaesthesia. One-third of the airway related catastrophies leading to brain damage or death occur as a result of inability in maintaining a patent airway.1 Clinical history, together with other anatomical characteristics of a patient's airway is an independent determinant in predicting the degree of difficulty during laryngoscopy.1 If significant airway difficulty is anticipated as a result of pathological lesions, some of the best options to secure the airway includes either an awake/sedated fibreoptic or blind nasal intubations. It has also been proven that the risk of difficult laryngoscopy increases in the presence of multiple specific abnormalities.2 3 Optimal laryngoscopy subjects to the proper positioning of the head and neck before attempting the laryngoscopy, application of external laryngeal pressure, choice of the neuromuscular blocking agent and the choice of the laryngoscope blade. During difficult airway scenarios, blades commonly mentioned in the literature are either curved or straight right-hand blades. We present here three cases with gross airway pathology that were successfully managed with the use of left-handed curved Macintosh blade, when the use of the conventional right-handed curved Macintosh blade resulted in a difficult laryngoscopy.
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Case 1 |
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A 40-yr-old male, 168 cm tall, weighing 68 kg presented with swelling of the right cheek for 4 months. Subsequent evaluation revealed a pleomorphic adenoma of the parotid gland involving oropharynx, nasopharynx and part of the hypopharynx. There was no history of stridor or intolerance to supine position. Airway examination showed that his mouth opening was 4.5 cm, with a modified Mallampati (MP)4 grade of IV. His neck movement, ability to prognath and temporomandibular distance were adequate. He was neither obese nor had any co-morbidities. The computed tomographic (CT) scan of the head and neck (Fig. 1) identified that the upper airway on the right side was compressed by the mass, resulting in significant narrowing and displacement of the available airway towards the left. There was no prior history of radio or chemotherapy. He was posted for the excision of the mass. After a preoperative assessment it was planned to secure the airway under general anaesthesia as the patient was anxious and unwilling to cooperate for an awake fibreoptic intubation. The back up plan in case of airway obstruction was to wake up the patient and to proceed with sedated fibreoptic intubation. Consent for an emergency tracheostomy was also obtained after explaining the risks involved in securing the airway. On the morning of surgery, he was premedicated with diazepam 0.1 mg kg–1 and metoclopropamide 10 mg orally 1 h before the procedure. The difficult airway cart with fibroscope and left-hand laryngoscopy blade was kept ready as difficult airway was anticipated.
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In the operating theatre, a peripheral i.v. line was started and routine monitoring was established. The patient was positioned supine with a pillow under the head (the sniffing position) and pre-oxygenated for 3 min. Surgeons were present and were ready to intervene in case of any eventualities. Anaesthesia was induced with titrated doses of propofol totalling up to 2.5 mg kg–1 over 90 s and fentanyl 1 mcgm kg–1 was administered. Jaw support was gently introduced and mask ventilation ensured and assisted. Anaesthesia was deepened with isoflurane 1%, nitrous oxide and oxygen (50:50) and then succinylcholine 1.5 mg kg–1 was administered i.v. Direct laryngoscopy by an experienced anaesthetist using a size 4 right-hand Macintosh blade revealed a grade IV5 laryngoscopic view. Laryngoscopy was repeated with a size 4 left-hand Macintosh blade, introducing it from the left side of the oral cavity. By this manoeuvre it was possible to push the mass and tongue to the right side and the laryngoscopic grade was found to be grade II.5 The trachea was intubated easily with a size 8 ID Portex (Portex Limited, UK) cuffed tracheal tube. The procedure was uneventful.
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Case 2 |
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A 38-yr-old male weighing 58 kg, 158 cm tall with similar complaints similar to that in the case described earlier (case 1) presented for the removal of a similar mass lesion (pleomorphic adenoma) in the right parotid region. Mouth opening and other airway parameters were similar to case 1 except that the size of the lesion was slightly smaller. The CT scan showed a similar deviation of the airway but to a lesser extent (Fig. 2). As the airway evaluation and the pathology of the lesion were similar to case 1, the plan of anaesthesia was similar to the earlier case and it was decided to use a left-hand scope for intubation. The airway could be secured easily with the use of the size 4 left-hand laryngoscope blade which revealed a grade II laryngoscopy. After securing the airway, laryngoscopy was attempted again from the right side of the mouth with a right-hand size 4 blade with the tracheal tube in situ. Only the hard palate could be seen in this manoeuvre.
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Case 3 |
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A 54-yr-old male, 175 cm tall and weighing 62 kg presented with hoarseness of the voice for 6 months and a sensation of stickiness in the throat for a couple of months. Clinical evaluation revealed a malignant supraglottic mass involving the right side of the vocal cords. Indirect laryngoscopy showed almost complete obstruction of the airway at the laryngeal inlet with an available lumen of about 4 mm. There was no history of stridor or breathing difficulty. The X-ray neck showed a mass at the level of larynx deviating the airway (Fig. 3) towards the left. He was posted for micro laryngoscopy and laser debulking of the lesion as he was not an ideal candidate for total laryngectomy. After obtaining consent for tracheostomy, it was planned to secure the airway under general anaesthesia as the patient was unwilling to cooperate for an awake fibreoptic intubation. The difficult airway cart with fibroscope and left-hand laryngoscopy blade was kept ready as difficult airway was anticipated. Anaesthesia was induced with propofol (2.5 mg kg–1) and fentanyl 1 mcgm kg–1 i.v. in a similar manner as that of case 1. After confirmation of effectiveness of mask ventilation an additional propofol 50 mg was administered i.v. and laryngoscopy was done with a left-hand size 4 laryngoscope blade to check the grade of laryngoscopy. It was found to be grade II with visibility of only the left vocal cord. A size 6.5 ID Portex (Portex Limited, UK) cuffed tracheal tube was introduced past vocal cords. After confirmation of the tube placement, atracurium 0.5 mg kg–1 was administered and anaesthesia was maintained with oxygen and nitrous oxide (50:50), isoflurane 1–1.5% and fentanyl as per requirement. After the airway was secured, a right-hand laryngoscopy was done as with case 2 and only the mass could be seen. The procedure was uneventful thereafter.
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Discussion |
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The incidence of difficult intubation requiring more than two attempts of laryngoscopies is around 1–4%, whereas the incidence of abandoned or failed intubation is about 0.005–0.35%.6 The use of the left-hand scope blade for management of difficult airway has neither been mentioned in literature nor is the left-hand blade included in the list of contents of the portable storage unit for the difficult airway management as described by the American Society of Anesthesiologists.7
The incidence of difficult airway because of a lesion on either side of the upper airway is not known. Salivary gland neoplasms (benign and malignant) constitute 2–4% of the head and neck neoplasms.8 Other important pathological lesions include lymphoma, pseudolymphoma, squamous cell carcinoma, nasopharyngeal carcinoma, schwannnomas and lesions resulting from infectious aetiologies [e.g. Epstein–Barr virus (infectious mononucleosis)]. The intubation techniques can be modified with inhalation agents under spontaneous ventilation for patients who are uncooperative. An alternative approach is to induce with a short acting i.v. agent (propofol)9 or by inhalation agents and once ventilation is assured; intubations can be facilitated with the use of short acting neuromuscular blocking drugs with or without use of adjuncts such as gum elastic bougie or stylet. We preferred to induce these patients with propofol as the pharmacokinetics and pharmacodynamics of propofol makes it a viable alternative to induction with inhalation agents in these clinical settings.9 In the presence of partial airway narrowing as seen in our cases, inhalational induction may be prolonged. The administration of titrated doses of propofol through the i.v. route allows control of both the speed and the depth of anaesthesia.9 However, it should be remembered that bolus doses of propofol as used by us are associated with dose dependant apnoea. In addition, propofol as an infusion instead of intermittent boluses would have been ideal in these scenarios. Another technique mentioned in airway management of similar pathological conditions is the use of paraglossal straight blade but, this can be used only when the obstruction is central and not for lesions grossly involving either side of the airway.10
Mention regarding left-hand scope in literature relates to its use in procedures mandating the tracheal tube fixation on the left side of the mouth for procedures such as microlaryngoscopies.11 A left-hand scope can be used in these types of cases where anatomy and contour of the blade manoeuvres the tongue and the right sided lesion, leaving an unobstructed left sided view of the glottis. In our third case with a supraglottic mass we intubated without a neuromuscular blocking agent, as we were not sure of ventilation. Intubations without use of neuromuscular blocking agent are no longer a rarity and there are studies supporting this.12
The use of a left-hand scope itself is not free of difficulties, as its use particularly in difficult airway situations requires prior practice of handling the scope. As a good technique of laryngoscopy depends on the prior experience of the laryngoscopist, it may be reasonable to conclude that left-hand blade may not be useful in inexperienced hands. The use of the left-hand laryngoscope blade needs practice and expertise and, the right-handed person would probably not be comfortable negotiating the tracheal tube into the trachea with the left hand.
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Acknowledgments |
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We acknowledge our patients who consented for writing this article and Dr Nandini Korula, Professor, Department of Anaesthesia, Christian Medical College, Vellore, for her valuable input and guidance during the preparation of this manuscript.
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References |
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1 el-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg 1996; 82:1197–204[Abstract]
2 Wilson ME, Spiegelhalter D, Robertson JA, Lesser P. Predicting difficult intubation. Br J Anaesth 1988; 61:211–6
3 Rose DK and Cohen MM. The airway: problems and predictions in 18,500 patients. Can J Anaesth 1994; 41:372–83[Web of Science][Medline]
4 Samsoon GL and Young JR. Difficult tracheal intubation: a retrospective study. Anaesthesia 1987; 42:487–90[Web of Science][Medline]
5 Cormack RS and Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia 1984; 39:1105–11[Web of Science][Medline]
6 Benumof JL. Difficult laryngoscopy: obtaining the best view. Can J Anaesth 1994; 41:361–5[Web of Science][Medline]
7 Anesthesiology Practice guidelines for management of the difficult airway. A report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. 1993; 78:597–602
8 Spiro RH. Salivary neoplasms: overview of a 35-year experience with 2,807 patients. Head Neck Surg 1986; 8:177–84[Web of Science][Medline]
9 Ludbrook GL, Hitchcock M, Upton RN. The difficult airway: propofol infusion as an alternative to gaseous induction. Anaesth Intensive Care 1997; 25:71–3[Web of Science][Medline]
10 Henderson JJ. The use of paraglossal straight blade laryngoscopy in difficult tracheal intubation. Anaesthesia 1997; 52:552–60[CrossRef][Web of Science][Medline]
11 Carter JH. Microlaryngoscopy and the left-handed laryngoscope. Anaesthesia 1999; 54:203[Web of Science][Medline]
12 Wong AK and Teoh GS. Intubation without muscle relaxant: an alternative technique for rapid tracheal intubation. Anaesth Intensive Care 1996; 24:224–30[Web of Science][Medline]
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