Plan B

07_Plan-B

This Skill Station covers:

-Fibre optic assisted intubation via the Berman airway

-Fibre optic assisted intubation via the LMA

-Fibre optic assisted intubation via the LMA using an Aintree Intubating Catheter

-Use of the Intubating LMA (Fastrach™) with fibre optic guidance

-Use of the Intubating LMA for blind intubation

-The indications, contraindications and complications of these fibre optic techniques, and their role within the DAS guidelines

The Equipment

The Berman airway
The Cook Aintree Intubating Catheter
The Classic LMA
The Proseal LMA
The igel LMA
The AuraGain LMA
The Intubating LMA

The Essentials

Fibre optic intubation via a conduit is a relatively low skill technique that can be very useful in the management of the difficult airway, both anticipated and unanticipated. In the case of the unanticipated difficult airway, it might form part of Plan B of the DAS guidelines (the “can’t intubate can ventilate” situation). The technique can also be used electively in the management of the known difficult airway and in patients with C-spine injuries.

The conduits used for this technique include laryngeal mask airways (LMAs), of which there are many types, and specifically designed oral airways (such as the Berman airway).

The intubating LMA™ is an excellent conduit for tracheal intubation. It is used in Plan B of the DAS guidelines but can also be useful in the elective management of the known difficult airway and in patients with C-spine injuries. In the latter group, fluoroscopic and ultrasound studies have demonstrated decreased movement of the cervical spine with the ILMA than direct laryngoscopy with manual in-line stabilisation.1,2 The ILMA can be used for blind intubation, but should be used in conjunction with a fibre optic bronchoscope wherever possible, as fibre optically guided techniques are always superior to blind techniques.3

Fibre optic guidance is the gold standard, but when used correctly, blind techniques have a success rate of greater than 90%:

-Blind insertion in patients without difficult airways: 95.7%.4

-Blind insertion in patients with known or anticipated difficult airways: 64% first pass, 92% overall, other 8% achieved with fibre optic technique.5

-In unanticipated difficult airways: one study of 23 patients – 75% first pass blind insertion, 100% overall insertion.5

-Using the blind technique, oesophageal intubation may be up to 5%.6

-Fibre optic technique improves first attempt success rate,5 overall insertion success rate,7 and nearly always succeeds when blind technique fails.8

A learning curve of about 20 insertions has been described,9 and studies with novice users suggest that high success rates can be achieved with minimal training.10,11

Standard Portex or Mallinckrodt PVC tubes can be used successfully with the device,12 and if used, should be inserted in the reverse orientation (against their natural curve), as this decreases the angle of emergence of the device and improves insertion rates.13

In contrast to the ILMA, blind success rates with other LMAs are low,14,15 but can be improved to 90-100% with fibre optic guidance.7,16

There are many examples in the literature of successful difficult airway management using the Aintree Intubating Catheter™ (AIC) in combination with the classic LMA™ and Proseal LMA™.17,18 Evidence suggests that passage of the AIC via the Proseal LMA™ is as easy and reliable as via the classic LMA™.19 The Supreme LMA™ does not seem to be suitable for this purpose as the angle of exit of the AIC from the device is unpredictable due to the epiglottic fins in its bowl.20

After successfully inserting a tracheal tube through an LMA, it is tempting to try to remove the LMA, leaving the tube in place. This is not recommended,21 except in the case of the intubating LMA, as this device is specifically designed to be removed, and comes with a stabilising rod to facilitate the procedure. During anaesthesia for surgery, the LMA is very unlikely to cause harm.22 If intubation is to be prolonged, an airway exchange catheter can be used to facilitate LMA removal.

Features of different laryngeal mask airways

LMA / tube compatibilities

Top Tips

-If difficulties placing supraglottic airway device, ensure head in neutral position, reduce or remove cricoid pressure, try withdrawing by 4 – 5cm then reinserting, ensure adequate sedation/relaxation.

-Use of tubes other than those in Table 2 increases the risk of the cuff sitting above or at the level of the vocal cords and therefore the chance of accidental extubation.

-The aperture bars of a classic LMA can be removed with a scalpel or scissors to facilitate the passage of the tracheal tube.

-Use of the Aintree Intubating Catheter is preferable because:

  • It enables the insertion of larger tracheal tubes
  • It allows removal of the LMA
  • It reduces the likelihood of the tracheal tube getting caught on the LMA aperture bars
  • It enables oxygenation via the Rapi-fit™ connector in case of difficulty passing tracheal tube

-Blind techniques should be avoided whenever possible. Only use the ILMA for blind intubation if a fibre optic scope is not available.

-If tube not passing during blind ILMA technique, try Chandy manoeuvre or withdraw ILMA slightly

-ILMA can be reinserted (over tube left in place) for extubation to facilitate recovery and airway maintenance or enable deep extubation

Plan B - Video 1

Plan B - Video 2 (ILMA)

References

  1. Sahin A, Salman MA, Erden IA, Aypar U. Upper cervical vertebrae movement during intubating laryngeal mask, fibreoptic and direct laryngoscopy: a video-fluoroscopic study. European journal of anaesthesiology. 2004;21(10):819-823.
  2. Gercek E, Wahlen BM, Rommens PM. In vivo ultrasound real-time motion of the cervical spine during intubation under manual in-line stabilization: a comparison of intubation methods. European journal of anaesthesiology. 2008;25(1):29-36.
  3. Frerk C, Mitchell VS, McNarry AF, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. British journal of anaesthesia. 2015;115(6):827-848.
  4. Caponas G. Intubating laryngeal mask airway. Anaesthesia and intensive care. 2002;30(5):551-569.
  5. Ferson DZ, Rosenblatt WH, Johansen MJ, Osborn I, Ovassapian A. Use of the intubating LMA-Fastrach in 254 patients with difficult-to-manage airways. Anesthesiology. 2001;95(5):1175-1181.
  6. Dimitriou V, Voyagis GS. Blind intubation via the ILMA: what about accidental oesophageal intubation? British journal of anaesthesia. 1999;82(3):478-479.
  7. Pandit JJ, MacLachlan K, Dravid RM, Popat MT. Comparison of times to achieve tracheal intubation with three techniques using the laryngeal or intubating laryngeal mask airway. Anaesthesia. 2002;57(2):128-132.
  8. Joo HS, Kapoor S, Rose DK, Naik VN. The intubating laryngeal mask airway after induction of general anesthesia versus awake fiberoptic intubation in patients with difficult airways. Anesthesia and analgesia. 2001;92(5):1342-1346.
  9. Parr MJ, Gregory M, Baskett PJ. The intubating laryngeal mask. Use in failed and difficult intubation. Anaesthesia. 1998;53(4):343-348.
  10. Timmermann A, Russo SG, Crozier TA, et al. Laryngoscopic versus intubating LMA guided tracheal intubation by novice users–a manikin study. Resuscitation. 2007;73(3):412-416.
  11. Levitan RM, Ochroch EA, Stuart S, Hollander JE. Use of the intubating laryngeal mask airway by medical and nonmedical personnel. The American journal of emergency medicine. 2000;18(1):12-16.
  12. Kundra P, Sujata N, Ravishankar M. Conventional tracheal tubes for intubation through the intubating laryngeal mask airway. Anesthesia and analgesia. 2005;100(1):284-288.
  13. Zhu T. Conventional endotracheal tubes for intubation through the intubating laryngeal mask airway. Anesthesia and analgesia. 2007;104(1):213; author reply 213-214.
  14. Lim SL, Tay DH, Thomas E. A comparison of three types of tracheal tube for use in laryngeal mask assisted blind orotracheal intubation. Anaesthesia. 1994;49(3):255-257.
  15. Asai T. Blind tracheal intubation through the laryngeal mask. Canadian journal of anaesthesia = Journal canadien d’anesthesie. 1996;43(12):1275.
  16. Koga K, Asai T, Latto IP, Vaughan RS. Effect of the size of a tracheal tube and the efficacy of the use of the laryngeal mask for fibrescope-aided tracheal intubation. Anaesthesia. 1997;52(2):131-135.
  17. Cook TM, Seller C, Gupta K, Thornton M, O’Sullivan E. Non-conventional uses of the Aintree Intubating Catheter in management of the difficult airway. Anaesthesia. 2007;62(2):169-174.
  18. Higgs A, Clark E, Premraj K. Low-skill fibreoptic intubation: use of the Aintree Catheter with the classic LMA. Anaesthesia. 2005;60(9):915-920.
  19. Blair EJ, Mihai R, Cook TM. Tracheal intubation via the Classic and Proseal laryngeal mask airways: a manikin study using the Aintree Intubating Catheter. Anaesthesia. 2007;62(4):385-387.
  20. Greenland KB, Tan H, Edwards M. Intubation via a laryngeal mask airway with an Aintree catheter – not all laryngeal masks are the same. Anaesthesia. 2007;62(9):966-967.
  21. Alexander R. Do not remove the laryngeal mask airway. Anesthesia and analgesia. 1999;89(2):536-537.
  22. Keller C, Brimacombe J. Mucosal pressure and oropharyngeal leak pressure with the ProSeal versus laryngeal mask airway in anaesthetized paralysed patients. British journal of anaesthesia. 2000;85(2):262-266.