This Article Full Text (PDF) Submit a scholarly reply Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Agrò, F. E. Articles by Petitti, T. Search for Related Content PubMed PubMed Citation Articles by Agrò, F. E. Articles by Petitti, T.

Relationship between body mass index and ventilation with the Laryngeal Tube® in 228 anesthetized paralyzed patients: a pilot study

Rome, Italy

To the Editor:

The Laryngeal Tube® (LT; VBM, Medizintechnik, GmbH, Sulz, Germany) is a novel airway device consisting of a silicone airway tube and two cuffs. Once inserted, the proximal cuff lies in the hypopharynx and the distal cuff in the upper esophagus (Figure). We conducted a pilot study to assess the efficacy of the LT^1–3 throughout the surgical procedure and to determine whether the ability to obtain an effective airway with the LT is affected by the body mass index (BMI) of patients.

View larger version (72K): [in this window] [in a new window]   FIGURE A, RX control = correct position of the Laryngeal Tube® (LT); B, = anatomic view, correct position of the LT hole just in front of the laryngeal inlet.

Patients were divided in three groups, based on BMI: 1 < 20 kg•m^-2, 2 = 20–24.9 kg•m^-2, and 3 = 25–30 kg•m^-2. The LT size was chosen according to patient height: size 3 (< 155 cm), size 4 (155–180 cm), size 5 (> 180 cm). The LT was inserted with the head in the sniffing position. Cuffs were inflated to a pressure of 60 cm H₂O. To evaluate the airway, the following scoring system was used: 1 = easy (immediate effective ventilation); 2 = difficult (effective ventilation after adjustment of the position of the LT); 3 = impossible (ventilation not achieved, tracheal intubation performed). Data were compared using the Spearman correlation test (significant P < 0.05). Duration of anesthesia ranged between 20 and 90 min. The hemodynamic variables remained stable throughout the surgery. In 95.6% patients an effective ventilation was obtained: 72.5% could be ventilated immediately; 27.5% needed further maneuvers to obtain effective ventilation (the device was pulled up in 42/59 patients and it was pushed down in 17/59). In 4.4% of patients, ventilation was impossible and tracheal intubation had to be performed. Oxygen saturation remained above 98% in all patients. The patients presented neither regurgitation nor other respiratory problems. After removal, 1.0% patients coughed, 2.6% suffered from sore throat and 1.5% from pain on swallowing. No patient had any adverse event after 24 hr. The high rate (95.6%) of effective ventilation suggests that the LT may be a reliable device for airway management and we found that the effectiveness of the LT does not decrease over time.⁴

Mean BMI (± standard deviation) was 23.9 ± 2.4 kg•m^-2. There were 18 patients in Group I, 138 in Group II and 72 in Group III and adjustment of device position was required in three (17%), 29 (21%) and 27 (38%) respectively. A significant correlation between BMI and the airway scoring system was present (P < 0.001). Goodman et al.⁵ showed a correlation between increasing BMI and decreasing pharyngeal height. Furthermore, there is an inverse relationship between increasing BMI and pharyngeal area. Such observations reinforce our finding.

In conclusion, the LT provided effective ventilation during general anesthesia. Correct LT positioning may require more adjustments in patients with an increasing BMI.

References

1 Agrò F, Cataldo R, Alfano A, Gallì B. A new prototype for airway management in an emergency: the laryngeal tube. Resuscitation 1999; 41: 284–6.[Medline]

2 Agrò F, Gallì B, Ravussin P. Preliminary results using the laryngeal tube for supraglottic ventilation. Am J Emerg Med 2002; 20: 57–8.[Medline]

3 Agrò F, Cataldo R, Alfano A, Gallì B, Ravussin P. A comparison of two new devices for emergency airway management: laryngeal tube and airway management device. Am J Emerg Med 2001; 19: 163–4.[Medline]

4 Asai T, Murao K, Shingu K. Efficacy of the laryngeal tube during intermittent positive-pressure ventilation. Anaesthesia 2000; 55: 1099–102.[Medline]

5 Goodman EJ, Eisenmann UB, Dumas SD. Correlation of pharyngeal size to body mass index in the adult. Anesth Analg 1997; 84: 584.

This article has been cited by other articles:

				A. A. Matioc and J. Olson Use of the Laryngeal TubeTM in two unexpected difficult airway situations: lingual tonsillar hyperplasia and morbid obesity: [L'usage du Laryngeal TubeTM dans deux situations d'intubation difficile inattendue : hyperplasie des amygdales linguales et obesite morbide] Can J Anesth, December 1, 2004; 51(10): 1018 - 1021. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) Submit a scholarly reply Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Agrò, F. E. Articles by Petitti, T. Search for Related Content PubMed PubMed Citation Articles by Agrò, F. E. Articles by Petitti, T.