Effect of high laryngeal mask airway intracuff pressure on the laryngopharyngeal mucosa of dogs.
OBJECTIVE
To evaluate the effect of increased of laryngeal mask airway (LMA) intracuff pressures on the laryngopharyngeal mucosa.


METHODS
Animal model.


METHODS
Sixteen mixed-breed dogs were randomly allocated to two groups, G1 (intracuff volume, 30 mL; n = 8) and G2 (intracuff volume, 54 mL; n = 8), to produce, respectively, high or very high intracuff pressures. Anesthesia was induced and maintained with pentobarbital. Intracuff pressures were measured immediately after insertion and inflation of a No. 4 laryngeal mask airway (LMA) and 30, 60, 90, and 120 minutes thereafter. The dogs were euthanized, and biopsy specimens from eight predetermined areas of the laryngopharynx in contact with LMA cuff were collected for light microscopic (LM) and scanning electron microscopic (SEM) examination.


RESULTS
Initial LMA cuff inflation in G1 and G2 resulted in intracuff pressures of 119 mm Hg +/- 4 mm Hg and 235 mm Hg +/- 13 mm Hg, respectively. Over a 2-hour period, the intracuff pressure decreased significantly in G1 (P < .001) and G2 (P < .01), and there was a significant difference between the groups over time (P < .001). The LM study of laryngopharyngeal mucosa in both groups showed mild congestion in the subepithelial layer. There were no differences between the groups (P > .10) or among the areas sampled (P > .10). In some areas of G2, the SEM study showed epithelial desquamation that was more intense than that in G1.


CONCLUSIONS
The increase in LMA intracuff pressure caused only mild alterations in the laryngopharyngeal mucosa of the dog.
Martins
R H
RH
Department of Otorhinolaryngology, College of Medicine, University of São Paulo State, Botucatu, Brazil.
Braz
J R
JR
Defaveri
J
J
Gregório
E A
EA
Abud
T M
TM
D000818:Animals; D004285:Dogs; D005260:Female; D017214:Laryngeal Masks; D007830:Larynx / Q000293:injuries* / Q000473:pathology; D008297:Male; D008855:Microscopy, Electron, Scanning; D009092:Mucous Membrane / Q000293:injuries / Q000473:pathology; D010614:Pharynx / Q000293:injuries* / Q000473:pathology; D011312:Pressure