ILMA in cervical spine immobilization

* E-mail: c.goutcher{at}ntlworld.com

Editor—We read with interest the recent article by Komatsu and colleagues1 describing the use of the intubating laryngeal mask (ILMA) when the cervical spine has been immobilized by a rigid collar. We would agree that blind intubation through an ILMA is a reasonable choice in experienced hands in the elective, fasted patient. However, we question the authors' statement that the ILMA is a reasonable strategy when tracheal intubation is required with a degree of urgency.

Reduced mouth opening (inter-incisor distance) of <25 mm has been cited as contributing to the failure of insertion of the ILMA.2 Heath3 suggested a reduction in mouth opening as the main factor contributing to the poorer view at laryngoscopy when a cervical collar is applied. Our own data suggest mouth opening with a cervical collar in place is very variable and a significant proportion of people do not have the 20 mm of mouth opening recommended by Brain and colleagues.4

The authors mention direct laryngoscopy with the aid of a gum elastic bougie but fail to mention the other option in this situation, which is to remove the front part of the collar after induction together with manual in-line stabilization. This tech-nique has been shown to be safe and effective.5 We would suggest that this should be the method of choice for immobilizing the cervical spine in the urgent/emergency situation before any instrumentation, to optimize the chances of a rapid, successful intubation.

C. M. Goutcher* and V. Lochhead

Glasgow, UK


 
* E-mail: sessler{at}louisville.edu

Editor—As specified in the discussion section of our article, we agree with Drs Goutcher and Lochhead that the ILMA is not first choice for airway management in emergency situations. We conclude this because the oesophagus was initially intubated in 14% of our patients and 34% required multiple intubation attempts. Furthermore, the ILMA exerts considerable pressure against cervical vertebrae,6 which may be harmful to patients with unstable cervical spine.

We also agree that mouth opening of <25 mm often leads to failed ILMA insertion. In our study population, the patients with a collar had a significantly smaller mean (SD) mouth opening (41 (8) mm) than those without a collar (46 (7) mm), although, it is highly unlikely that this small difference is clinically important. What is important, is that none of our patients had a mouth opening distance of <25 mm, even with appropriately sized cervical collars in place (Tracheostomy Philadelphia Cervical Collar Co., Thorofare, NJ, USA). This contrasts with the experience of Drs Goutcher and Lochhead whose patients frequently have a mouth opening distance <20 mm. It is likely that this difference results from the different collars used in the two studies.

Goutcher and Lochhead suggested direct laryngoscopy with removal of the front part of the collar and application of manual in-line stabilization as the method of choice in emergency situations. We agree, because cervical spine movement during direct laryngoscopy is less with manual in-line stabilization than with a cervical collar.7 We note, though, that patients with suspected cervical spine injuries often require intubation under suboptimal roadside conditions where application of manual in-line stabilization may be difficult owing to positioning restrictions (i.e. victims trapped in a car) or lack of skilled personnel. Under such conditions, the ILMA should be considered as one part of the strategy to secure the airway.

R. Komatsu, D. I. Sessler* and M. Ozaki

Louisville, KY, USA

References

1 Komatsu R, Nagata O, Kamata K, Yamagata K, Sessler DI, Ozaki M. Intubating laryngeal mask airway allows tracheal intubation when the cervical spine is immobilised by a rigid collar. Br J Anaesth 2004; 93: 655–9[Abstract/Free Full Text]

2 Preis C, Czerny C, Preis I, Zimpfer M. Variations in ILMA external diameters: another cause of device failure. Can J Anaesth 2000; 47: 886–9[Abstract/Free Full Text]

3 Heath KJ. The effect on laryngoscopy of different cervical spine immobilistion techniques. Anaesthesia 1994; 49: 843–5[ISI][Medline]

4 Brain AIJ, Verghese C, Addy EV, Kapila A. The intubating laryngeal mask. I: Development of a new device for intubation of the trachea. Br J Anaesth 1997; 79: 699–703[Abstract/Free Full Text]

5 Criswell JC, Parr MJA, Nolan JP. Emergency airway management in patients with cervical spine injuries. Anaesthesia 1994; 49: 900–3[ISI][Medline]

6 Keller C, Brimacombe J, Keller K. Pressures exerted against the cervical vertebrae by the standard and intubating laryngeal mask airways: a randomized, controlled cross-over study in fresh cadavers. Anesth Analg 1999; 89: 1296–300[Abstract/Free Full Text]

7 Majernick TG, Bieniek R, Houston JB, Hughes HG. Cervical spine movement during orotracheal intubation. Ann Emerg Med 1986; 15: 417–20[ISI][Medline]