EUROANESTHESIA 2008 Copenhagen, Denmark, 31 May - 3 June RC2

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1 FIBREOPTIC INTUBATION: MODERN CLINICAL PRACTICE EUROANESTHESIA 2008 Copenhagen, Denmark, 31 May - 3 June RC2 ADRIAN C. PEARCE Department of Anaesthesia Guy s and St Thomas Hospital London, United Kingdom Saturday, May 31, :00-14:45 Room C1-M5 Since the first description of flexible fibreoptic intubation (FOI) by Murphy in 1967, there has been a variable uptake of the technique in European countries. Its availability is limited by cost, and practice is required to master the technique. It is simply not possible for all anaesthetists to go on a course to learn FOI initially and many anaesthetists find they do not use the technique often enough to remain proficient. In expert hands it remains the gold-standard for intubation through the nose or mouth in the awake or anaesthetised patient, offering a visual technique with a high success rate and extremely infrequent serious complications. The core roles of the flexible fibrescope in anaesthetic practice are: placement and checking of a double lumen tube or bronchial blocker checking the position of a single lumen tube or tracheostomy inspection and suctioning of the tracheobronchial tree inspection during siting of a percutaneous tracheostomy fibreoptic intubation There have been two notable recent advances in airway management that permit the use of the term modern clinical practice to fibreoptic intubation: low-skill fibreoptic intubation and incorporation of FOI within national airway management guidelines. LOW-SKILL FIBREOPTIC INTUBATION Low-skill FOI, a term apparently first used in 2001, denotes a technique of FOI which requires minimal skill, is easily learnt and can be mastered by all anaesthetists making it a core skill. Low-skill techniques bring FOI to all anaesthetists. FOI VIA A CLASSIC LARYNGEAL MASK OR SIMILAR SUPRAGLOTTIC AIRWAY There are four described techniques which allow FOI via the laryngeal mask airway and one or more of these techniques are suitable for use with the Classic, Proseal and intubating laryngeal mask airways. The supraglottic airway is functioning as a dedicated airway, defined by Charters and O Sullivan [1] as an upper airway device dedicated to the maintenance of airway patency while other major airway interventions are anticipated or in progress. Classic technique This involves placement of a laryngeal mask and the introduction through it of a fibrescope with tracheal tube loaded on it, first described in 1991 [2]. The fibrescope is advanced to the lower trachea and the tube advanced into the trachea. The fibrescope can be used to confirm accurate placement of the tube in relationship to the carina. This technique has a success rate with minimal training of >90% and is particularly useful with the Classic (re-usable) laryngeal mask airway. Tips to aid success with the Classic laryngeal mask airway are described in Table 1. TABLE 1. FIBREOPTIC INTUBATION THROUGH A CLASSIC LARYNGEAL MASK AIRWAY Place the laryngeal mask in a good position A size 6.0 mm tracheal tube will usually go through the size 3/4 laryngeal mask airway and size 7.0 mm through a size 5 Check that the selected tracheal tube can be advanced through the stem before use A long tube is required, so consider a microlaryngeal, armoured or long north-facing RAE tube It is a tight fit between tube and stem so make certain the tube cuff is flat and lubrication is used The laryngeal mask airway can be left in-situ unless access to the mouth is required A tube exchange catheter can be placed down the originally inserted tube which will allow removal of the tube and laryngeal mask airway and re-insertion of any size/design tube over the catheter

2 Aintree catheter The Aintree catheter [3] is a hollow bougie designed to fit over the intubating fibrescope. It is a semi-rigid tube with a length of 56 cm and internal diameter 47 mm. FOI through the Aintree catheter is described in Table 2. TABLE 2. FIBREOPTIC INTUBATION USING AN AINTREE CATHETER Place a Classic laryngeal mask or other similar supraglottic airway Confirm adequacy of ventilation through the laryngeal mask airway Slide the Aintree catheter onto fibrescope Advance fibrescope through the lumen of the laryngeal mask airway (Figure 1a) Position fibrescope in the distal trachea Hold fibrescope still and advance the Aintree catheter (Figure 1b) Remove fibrescope, stabilise the Aintree catheter and remove the laryngeal mask airway (Figure 1c) Intubate with a tracheal tube 7.0 mm or greater over the Aintree catheter (Figure 1d) Confirm correct position of the tracheal tube by capnography or fibrescope FIGURE 1A FIGURE 1B Fibrescope with Aintree catheter passed through lumen of laryngeal mask With the fibrescope tip in lower trachea, Aintree catheter will be advanced and fibrescope removed FIGURE 1C FIGURE 1D Stabilising the Aintree catheter in place and removing the laryngeal mask Railroading a 7.0 mm tube over the Aintree catheter

3 A recent study [4] in manikins showed that the Aintree catheter worked well with both the Classic and Proseal laryngeal mask airways, with a 95% success rate in about s. There are a number of case reports of successful use, a short review [5] of its use in airway rescue in 14 cases and several small published series with successful use even by inexperienced anaesthetists [6]. The author has used it successfully on three occasions in difficult cases. A recent case report [7] detailed its successful use in a 445 kg patient in whom awake FOI had failed. A size 5 Proseal laryngeal mask airway was placed under topical anaesthesia and anaesthesia induced with sevoflurane. Intubation was successful through the proseal in the anaesthetised patient. The Aintree catheter is available from Cook Medical ( and a poster detailing its use is available on the internet [8]. Arndt Airway Exchange Catheter set The Arndt system is also available from Cook Medical. At the time of writing the author has used the system successfully but as yet there are no published articles in peer-reviewed journals. The steps are described in Table 3. TABLE 3. FIBREOPTIC INTUBATION USING AN ARNDT AIRWAY EXCHANGE CATHETER Place a laryngeal mask or other similar supraglottic airway Advance the fibrescope (without tube) to the distal trachea Insert the wire anterogradely through the working/suction channel of the fibrescope Check through the fibrescope that the wire has entered the tracheobronchial tree Remove the fibrescope leaving the wire in the airway Insert the catheter over the wire Remove the laryngeal mask airway leaving the catheter in place Intubate over the catheter with the selected tube (minimum ID 5.0 mm) Remove catheter and confirm correct position of tracheal tube Fibreoptically placed bougie/introducer This technique was described in a letter [9]. It has not become widespread. In the author s view it is quite difficult to manipulate a standard introducer and 4.0 mm fibrescope in the stem of a Classic laryngeal mask but the author has been more successful using a 3.1 mm fibrescope. The steps are described in Table 4. TABLE 4. FIBREOPTIC INTUBATION USING A FIBREOPTICALLY-PLACED BOUGIE OR INTRODUCER Place a laryngeal mask airway Insert fibrescope into stem and view the larynx from above Insert a bougie/introducer alongside the fibrescope Pass the introducer through the laryngeal aperture under fibrescopic control Advance the introducer fully into the airway - it may need to be rotated through 180 to avoid the anterior tracheal wall Remove fibrescope, laryngeal mask airway, and intubate over the introducer ORAL INTUBATION THROUGH A BERMAN, WILLIAMS, OVASSAPIAN OR OTHER AIRWAY Several oral airways have been produced through which it is possible to advance the fibrescope and tube. The oral airway prevents biting of the fibrescope and is a conduit to the vocal cords. The Berman ( is available in the UK in sizes 8, 9 and 10 mm but seems to be available in seven sizes in the USA. If the correct size for the patient is chosen (generally the largest possible so that the tip engages in, or near, the vallecula), the fibrescope passes easily to the larynx and into the trachea. The tube can be advanced through the Berman airway and the airway is flanged so it can be removed over the inserted tube. The Williams airway (Anesthesia Associates, is not flanged but can be removed after removal of the tube connector. It is unfortunate that the largest Berman available is 10 mm because this is not long enough for many large males. A recent study compared the Berman and Williams airway as conduits for oral FOI in sixty patients [10]. The chance of gaining an unobstructed view of the larynx was greatest with the Williams. Another suitable airway is produced by VMB (Bronchoscope airway,

4 NASAL FOI WITH A LARYNGEAL MASK AIRWAY IN PLACE FOR VENTILATION Novices who are trying to use a fibrescope for nasotracheal intubation without training will do best when ventilation is continuous whilst the operator tries to find the larynx. One technique is to place a laryngeal mask airway and use this to maintain ventilation and anaesthesia whilst inserting the fibrescope through the nose advancing the scope to a depth of cm. Usually the view seen is of the back of the laryngeal mask and if this is now removed slowly the laryngeal aperture is straight ahead. AIRWAY MANAGEMENT STRATEGY A major development in the last 5 years has been the publication of national guidelines for airway management by several European countries. A national guideline will take account of the culture, equipment, knowledge and training in that particular country and the place of FOI will vary from being integral to non-existent. Clearly there is no point in suggesting a role for FOI in a national guideline unless it is a core skill. There is much blurring of the difference between the aspirations of a guideline and actual practice in operating rooms. Most guidelines have developed along the lines of suggesting an initial airway plan (Plan A) and a backup plan (Plan B). These plans are for the unanticipated and anticipated situations and will apply to both anaesthetised and awake patients. The role of the flexible fibrescope, which is a tool for intubation and not ventilation, can be summarised as described below. UNANTICIPATED DIFFICULT DIRECT LARYNGOSCOPY IN ELECTIVE SURGERY In this scenario the patient is anaesthetised (asleep) and long-acting muscle relaxants administered. It is one of the scenarios covered by the UK Difficult Airway Society guidelines [11] which are freely available in poster form from its website ( Plan A: Plan B: Attempt intubation by optimal direct laryngoscopy Maintaining general anaesthesia attempt low-skill FOI, or high-skill FOI for experienced users, during apnoea or with concurrent ventilation Plan C: If ventilation is difficult or FOI unsuccessful, proceed to oxygenation by facemask or laryngeal mask and awaken patient (Plan D is emergency oxygenation in the can t-intubate, can t-ventilate scenario) ANTICIPATED DIFFICULT INTUBATION The choice of technique may depend on whether facemask ventilation is expected to be easy or difficult, and is also influenced by the presence of a full stomach. Options (involving FOI) are: For difficult direct laryngoscopy and: known or expected easy facemask ventilation asleep, low or high-skill FOI with or without concurrent ventilation awake FOI known or expected difficult facemask ventilation awake FOI asleep FOI after placement of transtracheal catheter for ventilation known or expected difficult facemask ventilation and full stomach awake FOI MAINTAINING RESPIRATION OR VENTILATION DURING FOI There is an inherent safety in an intubation technique which allows ventilation at the same time. This occurs during awake FOI since the patient maintains their own spontaneous respiration during the whole endoscopy and intubation procedure. Ventilation can also be continued during FOI in the anaesthetised patient by maintaining spontaneous respiration and abolishing laryngeal reflexes by deep anaesthesia or topical anaesthesia. A recent study [12] compared target-controlled infusion of propofol with inhalational anaesthesia with sevoflurane for FOI in anaesthetised patients maintaining spontaneous respiration. More desaturation occurred in the propofol group. For the anaesthetised, paralysed patient Rüsch have produced two connectors (Universal adaptor, designed to fit between a facemask or laryngeal mask and the breathing system. The connector has a membrane with a 4 mm hole designed to produce a gas-tight seal around a standard intubating fibrescope. It is also possible, if intubating through a supraglottic airway, to place a standard bronchoscope connector on the tracheal tube once it is within the stem and ventilate through the tracheal tube

5 Another possibility is an adapted facemask from VBM ( with a suitable hole. Whilst this can be used with spontaneous or manual ventilation, its use has been examined in a French study [13] using pressure support ventilation (PSV) during FOI. Thirty-two patients with ENT cancer and at least two criteria for anticipated difficult intubation underwent FOI whilst anaesthetised with target-controlled infusion of propofol. The propofol blood level was set initially at 3 µg/ml but adjusted to maintain anaesthesia with spontaneous respiration. Glottic anaesthesia was obtained with 3 ml 2% lidocaine through the fibrescope before intubation. The patients were randomised to spontaneous respiration or pressure support ventilation with 10 cmh 2 O, and patients in the PSV group maintained higher tidal volumes and a lower end-tidal carbon dioxide. AWAKE FOI SEDATION Opioids produce good conditions for awake FOI providing analgesia and inhibition of the glottic and gag reflexes. However, there is the potential for hypoventilation or apnoea and a very careful watch should be maintained on the adequacy of respiration. Sedation regimes for awake FOI are a matter of clinician preference or experience but usually involve an opioid, benzodiazepine or hypnotic either as sole agent or in combination, by bolus increments or manually adjusted infusion. It is surprisingly easy to induce general anaesthesia inadvertently and the author would recommend the simultaneous use of no more than two classes of analgo-sedative drugs. A recent advance for many practitioners is the incorporation of target-controlled infusions (TCI) of remifentanil or propofol for sedation/analgesia. TCI could be expected to produce rapid, controllable and stable levels of sedation. Individual practitioners have their own favourite recipe. A recent study compared TCI remifentanil with TCI propofol in 24 patients undergoing awake FOI [14]. Remifentanil produced better conditions for endoscopy and intubation, but with more chance of recall. The use of awake FOI may be the primary Plan A for intubation and there must be an appropriate Plan B. Depending on the circumstances the options for Plan B include: a more experienced practitioner undertaking awake FOI placing a laryngeal mask and using this as a conduit for awake FOI an anterograde wire or catheter assisted FOI retrograde wire assisted surgical tracheostomy Fibrecapnic intubation was described in 2006 and involves placing a specially constructed capnography catheter through the working channel of the fibrescope. The catheter may be advanced into the trachea and successful tracheal location confirmed by capnography. The fibrescope can be advanced over the catheter into the trachea. A series of 40 consecutive intubations in 37 patients with advanced head and neck cancer was described [15]. Topical anaesthesia of the airway was obtained with lidocaine and sedation with 1% propofol run at an average of 15 ml/hr. Eighty percent of intubations were achieved within 4 min. The place of awake FOI as a core skill (that is, a competence for all anaesthetists) remains in doubt in many countries. A recent study of trainees in the UK and Ireland [16] found that trainees considered it necessary to undertake about 10 awake FOI to achieve competence but the median actual number achieved by the time of the last training year was only four. THE FUTURE Flexible FOI is undoubtedly a highly successful versatile, gold-standard procedure which can be used to manage the majority of difficult airway situations. However, the fibrescope is expensive to purchase and maintain, requires decontamination between patients and is easily damaged. In the UK there are now very strict procedures for decontamination which require sterilisation of the device before and after use. Modern decontamination procedures are no longer conducted within the operating theatre environment and the fibrescope has to be sent to a central location to ensure quality control. Stimulated by the threat of bovine spongiform encephalopathy (mad-cow disease), the prevailing culture in the UK is to use disposable airway equipment. For routine difficult intubation (difficult direct laryngoscopy) it is likely that a videolaryngoscope will become popular due in part to its ease of use, no requirement to attend a course of training, single use plastic inserts and reasonable success rate. Other possibilities are rigid stylets, rigid fibrescopes and systems built around fibrebundles

6 KEY LEARNING POINTS Low-skill fibreoptic intubation techniques are core skills Fibreoptic intubation through a supraglottic airway provides a very effective Plan B for unexpected difficult intubation Target-controlled infusions of propofol or remifentanil provide good quality sedation for awake intubation A primary airway management plan of awake fibreoptic intubation may fail and must be matched with a sensible Plan B The supremacy of flexible fibrescopes is being challenged by other devices such as videolaryngoscopes REFERENCES 1. Charters P, O Sullivan E. The dedicated airway : a review of the concept and an update of current practice. Anaesthesia 1999; 54: Silk JM, Hill HM, Calder I. Difficult intubation and the laryngeal mask. Eur J Anaesthesiol 1991; 4(Suppl): Hawkins M, O Sullivan E, Charters P. Fibreoptic intubation using the cuffed oropharyngeal airway and Aintree intubating catheter. Anaesthesia 1998; 53: Blair EJ, Mihai R, Cook TM. Tracheal intubation via the Classic and Proseal laryngeal mask airways: a manikin study using the Aintree intubation catheter. Anaesthesia 2007; 62: Cook TM, Seller G, Gupta K, Thornton M, O Sullivan E. Non-conventional uses of the Aintree intubation catheter in management of the difficult airway. Anaesthesia 2007; 62: Higgs A, Clark E, Premraj K. Low-skill fibreoptic intubation: use of the Aintree catheter with the classic LMA. Anaesthesia 2005; 60: Doyle DJ, Zura A, Ramachandran M, et al. Airway management in a 980-lb patient: use of the Aintree intubation catheter. J Clin Anesth 2007; 19: Allison A, McCrory J. Tracheal placement of a gum elastic bougie using the laryngeal mask airways. Anaesthesia 1990; 45: Greenland KB, Ha ID, Irwin MG. Comparison of the Berman intubating airway and the Williams airway intubator for fibreoptic orotracheal intubation in anaesthetised patients. Anaesthesia 2006; 61: Henderson JJ, Popat MT, Latto IP, Pearce AC. Difficult Airway Society guidelines for management of the unanticipated difficult intubation. Anaesthesia 2004; 59: Bonnin M, Therre P, Albuisson E, et al. Comparison of a propofol target-controlled infusion and inhalational sevoflurane for fibreoptic intubation under spontaneous ventilation. Acta Anaesthesiol Scand 2007, 51: Bourgain JL, Billard V, Cros AM. Pressure support ventilation during fibreoptic intubation under propofol anaesthesia. Br J Anaesth 2007; 98: Rai MR, Parry TM, Dombrovskis A, Warner OJ. Remifentanil target-controlled infusion vs propofol target-controlled infusion for conscious sedation for awake fibreoptic intubation: a double-blind randomised controlled trial. Br J Anaesth 2008 (in press). 15. Huitink JM, Balm AJM, Keijzer C, Buitelaar DR. Awake fibrecapnic intubation in head and neck cancer patients with difficult airways: new findings and refinements to the technique. Anaesthesia 2007; 62: McNarry AFM, Dovell T, Dancey EML, Pead ME. Perception of training needs and opportunities in advanced airway skills: a survey of British and Irish trainees. Eur J Anaesthesiol 2007; 24: