To the Editor:—
We read with interest the article by Dr. Brimacombe et al.1
regarding the new insertion technique of the ProSeal™
laryngeal mask airway (PLMA; Laryngeal Mask Company North America, San Diego, CA). The authors describe a gum elastic bougie (GEB)–guided insertion technique and demonstrate that the new insertion technique is more frequently successful than the (manufacturer-recommended) digital or introducer tool techniques. The GEB-guided insertion technique—a Seldinger technique—optimizes the PLMA insertion attempt: The mask easily negotiates the palatopharyngeal interface without folding over and is directed into the esophagus. In addition, the drain tube is aligned with the esophagus, optimizing orogastric tube insertion.
A potential disadvantage of the GEB-guided technique is that an assistant is needed to stabilize the PLMA at the proximal end while the intubator feeds 5–10 cm of GEB in the esophagus.
We describe an unassisted GEB-guided insertion technique of the PLMA and comment on our clinical experience. We modified the original approach1
to perform the unaided technique:
1. The PLMA was primed by inserting the GEB in the drain port such that 22 cm of the GEB was protruding from the distal end of the drain tube. This was realized by aligning the first GEB marking to the proximal end of the drain tube.
2. The GEB and PLMA were held as a unit with the dominant hand (fig. 1
). The straight end of the GEB was inserted into the esophagus 5–10 cm under visualization during a gentle laryngoscopy.
3. After the removal of the laryngoscope, the PLMA was positioned at the mouth opening. Before advancing the PLMA, the GEB position was confirmed by inserting an extra 3–5 cm into the esophagus.
4. Using the standard digital technique, the PLMA was inserted over the GEB with the dominant hand while the GEB was stabilized with the nondominant hand.
We used this technique in 10 successive male patients (American Society of Anesthesiologists physical status I or II; age, 20–80 yr) scheduled to undergo orthopedic procedures for which intubation was not required. We inserted the PLMA in the first attempt and confirmed effective ventilation by the same criteria as Brimacombe et al.
A gentle laryngoscopy does not usually allow visualization of the esophagus. The insertion of the GEB behind the larynx is blind and defined by the ability to feed the desired length of GEB without resistance. In our group, we marked the straight end of the GEB at 5 and 10 cm with a sterile marker and confirmed under direct visualization that the GEB was inserted close to or at the 10-cm mark. Misplacement of the GEB occurred in one patient outside this group when less GEB length was protruding from the PLMA and less than 5 cm was inserted retrolaryngeal. In this case, the tip was inserted in a perilaryngeal elastic structure (pyriform sinus), and the malposition was diagnosed before PLMA insertion as a failure of the GEB to advance (“elastic resistance” in step 3). We consider this step necessary because oropharyngeal tissues recover to their original features after laryngoscopy and may pull the GEB out of the esophagus a couple of centimeters. From the initial straight shape during laryngoscopy and insertion, the GEB assumes a curved shape during PLMA insertion because it molds to solid oropharyngeal structures (hard palate, posterior pharynx).
A limitation of our technique is the fact that the nondominant hand may be used during PLMA insertion to extend the head or for a jaw lift. In these cases, the GEB cannot be stabilized without an assistant and may be further inserted in the esophagus with the PLMA. Our technique must be validated in a large group of patients.
The assisted and unassisted GEB-guided PLMA techniques may be used in critical situations when an unexpected difficult airway is encountered or an optimized first insertion attempt is preferred.2
The GEB-guided PLMA technique has relevance as a teaching tool for the PLMA index finger technique because the smooth ride assured by the GEB should be reproduced with the standard insertion attempt.
The PLMA is a versatile device both in the operating room and outside the operating room. It was used as a rescue airway in an obstetric patient,3
in a patient with lingual tonsillar hyperplasia,4
in obese patients,5
in the intensive care unit,6
and in patients with manual in-line stabilization.7
The GEB-guided PLMA techniques warrant further research regarding GEB esophageal insertion in a patient with full stomach, the interaction with cricoid pressure, and the impact of these techniques on the unstable cervical spine.
Adrian A. Matioc M.D.,*
George A. Arndt M.D.
* Veterans Affairs Medical Center and University of Wisconsin, Madison, Wisconsin. email@example.com
1. Brimacombe J, Keller C, Judd DV: Gum elastic bougie–guided insertion of the ProSeal™ laryngeal mask airway is superior to the digital and introducer tool techniques. Anesthesiology 2004; 100:25–9
2. Brimacombe J, Lim Y, Keller C: ProSeal exchange using gum elastic bougie in the lateral body position. Anesthesia 2003; 58:1133–4
3. Awan R, Nolan JP, Cook TM: The use of Proseal LMA for airway maintenance during emergency Caesarean section after failed tracheal intubation. Br J Anaesth 2004; 92:140–3
4. Rosenblatt WH: The use of the LMA-ProSeal in airway resuscitation. Anesth Analg 2003; 97:1773–5
5. Keller C, Brimacombe J, Kleinsasser A, Brimacombe L: The laryngeal mask airway ProSeal as a temporary ventilatory device in grossly and morbidly obese patients before laryngoscope-guided tracheal intubation. Anesth Analg 2002; 94:737–40
6. Nixon T, Brimacombe J, Goldrick P, McManus S: Airway rescue with ProSeal laryngeal mask airway in the intensive care unit. Anesth Intensive Care 2003; 31:475–6
7. Asai T, Murao K, Shingu K: Efficacy of the ProSeal laryngeal mask airway during manual in line stabilization of the neck. Anaesthesia 2002; 918–920
© 2004 American Society of Anesthesiologists, Inc.