Revista Brasileira de Anestesiologia
Print version ISSN 0034-7094
MARTINS, Regina Helena Garcia et al. Effects of low laryngeal mask cuff pressure on the laryngopharyngeal mucosa of dogs. Rev. Bras. Anestesiol. [online]. 2001, vol.51, n.6, pp. 518-527. ISSN 0034-7094. http://dx.doi.org/10.1590/S0034-70942001000600007.
BACKGROUND AND OBJECTIVES: Injuries to laryngopharyngeal tissues and artery and nerve compression have been reported and attributed to high laryngeal mask (LM) cuff pressure. This study aimed at evaluating the laryngopharyngeal mucosa of dogs when in contact with LM cuff under low pressures and studying ventilatory conditions during anesthesia. METHODS: This study involved 8 mixed-breed dogs anesthetized with pentobarbital and maintained on mechanical ventilation after insertion of a number 4 LM. Pulse rate (PR), mean blood pressure (MBP), inspiratory pressure (IP), end tidal CO2 (PETCO2) and oxygen saturation (SpO2) were evaluated at 0 (control), 30, 60, 90 and 120 minutes after LM insertion. After euthanasia, laryngopharyngeal mucosa regions in contact with LM were biopsed and examined under light microscopy and scanning electron microscopy (SEM). RESULTS: The attributes studied have shown no significant changes during the experiment but a minor MBP and PETCO2 increase towards the end of the experiment. At light microscopy, laryngopharyngeal epithelium was normal in most examined areas, but in some areas a minor inflammatory reaction with infiltration of polinuclear neutrophils and mild congestion of the subepithelial layer was seen, without significant differences among areas (p < 0.05). At SEM no significant differences in the laryngopharyngeal mucosa was observed. CONCLUSION: In dogs, low LM cuff pressure (60 cmH2O) is safe for airway patency maintenance and does not affect laryngopharyngeal mucosa.
Keywords : ANIMAL [cão]; EQUIPAMENTOS [máscara laríngea].