High laryngeal mask airway pressures resulting from nitrous oxide do not increase pharyngeal mucosal injury in dogs

Purpose: During general anesthesia, nitrous oxide (N2O) diffuses rapidly into the air-filled laryngeal mask airway (LMA) cuff, increasing intracuff pressure. There is no clear correlation between LMA intracuff pressure and pressure on the pharynx. We have studied the effects of high LMA intracuff pressures secondary to N2O on the pharyngeal mucosa of dogs.Methods: Sixteen mongrel dogs were randomly allocated to two groups: G1 (intracuff volume, 30 mL; n = 8) breathed a mixture of O-2 (1 L.min(-1)) and air (1 L.min(-1)) and G2 (intracuff volume, 30 mL; n=8) a mixture of O-2 (1 L.min(-1)) and N2O (1 L.min(-1)). Anesthesia was induced and maintained with pentobarbitone. LMA cuff pressure was measured at zero (control), 30, 60, 90 and 120 min after #4 LMA insertion. The dogs were sacrificed, and biopsy specimens from seven predetermined areas of the pharynx in contact with the LMA cuff were collected for light (LM) and scanning electron microscopic (SEM) examination by a blinded observer.Results: LMA intracuff pressure decreased with time in G1 (P < 0.001) and increased in G2 (P < 0.001). There was a significant difference between the groups (P < 0.001). In both groups, the LM study showed a normal epithelium covering the pharyngeal mucosa and mild congestion in the subepithelial layer There were no differences between the groups (P > 0.10) or among the areas sampled (P > 0.05). In both groups, the SEM study showed a normal pharyngeal mucosa with mild superficial desquamation. Few specimens in G1 and G2 showed more intense epithelial desquamation.Conclusion: High LMA intracuff pressures produced by N2O do not increase pharyngeal mucosal injury in dogs.

Transcriptional changes associated with recurrent airway obstruction in affected and unaffected horses

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cephalometric and three-dimensional assessment of superior posterior airway space after maxillomandibular advancement

The purpose of this study was to quantify cephalometric and three-dimensional alterations of the posterior airway space of patients who underwent maxillomandibular advancement surgery. 20 patients treated by maxillomandibular advancement were selected. The minimal postoperative period was 6 months. The treated patients underwent cone-beam computed tomography at 3 distinct time intervals, preoperative (T1), immediate postoperative period up to 15 days after surgery (T2), and late postoperative period at least 6 months after surgery. The results showed that the maxillomandibular advancement promoted an increase in the posterior airway space in each patient in all the analyses performed, with a statistically significant difference between T2 and T1, and between T3 and T1, p < 0.05. There was a statistical difference between T2 and T3 in the analysis of area and volume, which means that the airway space became narrower after 6 months compared with the immediate postoperative period. The maxillomandibular advancement procedure allowed great linear area and volume increase in posterior airway space in the immediate and late postoperative periods, but there was partial loss of the increased space after 6 months. The linear analysis of airway space has limited results when compared with analysis of area and volume.

Effects of age and gender on upper airway, lower airway and upper lip growth

The aim of the present retrospective study was to evaluate the influence of age and gender on upper and lower airway width and upper lip length. In this study, 390 lateral cephalograms were divided into 13 age groups (ranging from 6 to 18 years) and were analyzed. The inter-group differences were analyzed using a MANOVA (Multivariate Analysis of the Variance), and the intragroup differences were analyzed using an ANOVA (Analysis of the Variance) and Tukey's test. The results of the present study indicated that although the airway width and the upper lip length increased with age, the lower airway width exhibited variable growth between the ages of six and eighteen years. The airway width was significantly greater in females than males, whereas the upper airway width was similar between these two genders. The lip length was significantly shorter in females than males. The lower airway width and upper lip length were significantly different between males and females, whereas the upper airway width was similar for the genders. The upper airway width and upper lip exhibited incremental growth between the ages of six and eighteen years. The upper lip closely followed the growth pattern of the upper airway width; the growth plateaued between the ages of 6 and 9 years, increased from 9 to 16 years and plateaued from 16 to 18 years.

Maxillo-mandibular counter-clockwise rotation and mandibular advancement with TMJ Concepts (R) total joint prostheses Part II - Airway changes and stability

The purpose of this study was to evaluate the anatomical changes and stability of the oropharyngeal airway and head Posture following TMJ reconstruction and mandibular advancement with TMJ Concepts custom-made total joint prostheses and maxillary osteotomies with counter-clockwise rotation of the maxillo-mandibular complex. All patients were operated at Baylor University Medical Center, Dallas TX, USA, by one surgeon (Wolford). The lateral cephalograms of 47 patients were analyzed to determine surgical and post-surgical changes of the oropharyngeal airway, hyoid bone and head posture. Surgery increased the narrowest retroglossal airway space 4.9 mm. Head Posture showed flexure immediately after surgery (-5.6 +/- 6.7 degrees) and extension long-term post surgery (1.8 +/- 6.7 degrees); cervical curvature showed no significant change. Surgery increased the distances between the third cervical vertebrae and the menton 11.7 +/- 9.1 mm and the third cervical vertebrae and hyoid 3.2 +/- 3.9 mm, and remained stable. The distance from the hyoid to the mandibular plane decreased during surgery (-3.8 +/- 5.8 mm) and after surgery (-2.5 +/- 5.2 mm), Maxillo-mandibular advancement with counter-clockwise rotation and TMJ reconstruction with total joint prostheses produced immediate increase in oropharyngeal airway dimension, which was influenced by long-term changes in head posture but remained stable over the follow-up period.

Cephalometric Evaluation of Pharyngeal Airway Space Changes in Class III Patients Undergoing Orthognathic Surgery

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Indigofera suffruticosa Mill as new source of healing agent: Involvement of prostaglandin and mucus and heat shock proteins

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of limonene and essential oil from Citrus aurantium on gastric mucosa: Role of prostaglandins and gastric mucus secretion

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Role of Mucus in Mytella falcata (Orbigny 1842) Gills from Polluted Environments

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Regulation of ventilation in the caiman (Caiman latirostris): effects of inspired CO2 on pulmonary and upper airway chemoreceptors

In order to study the relative roles of receptors in the upper airways, lungs and systemic circulation in modulating the ventilatory response of caiman (Caiman latirostris) to inhaled CO2, gas mixtures of varying concentrations of CO2 Were administered to animals breathing through an intact respiratory system, via a tracheal cannula by-passing the upper airways (before and after vagotomy), or via a cannula delivering gas to the upper airways alone. While increasing levels of hypercarbia led to a progressive increase in tidal volume in animals with intact respiratory systems (Series 1), breathing frequency did not change until the CO2 level reached 7%, at which time it decreased. Despite this, at the higher levels of hypercarbia, the net effect was a large and progressive increase in total ventilation. There were no associated changes in heart rate or arterial blood pressure. on return to air, there was an immediate change in breathing pattern; breathing frequency increased above air-breathing values, roughly to the same maximum level regardless of the level of CO2 the animal had been previously breathing, and tidal volume returned rapidly toward resting (baseline) values. Total ventilation slowly returned to air breathing values. Administration of CO2 via different routes indicated that inhaled CO2 acted at both upper airway and pulmonary CO2-sensitive receptors to modify breathing pattern without inhibiting breathing overall. Our data suggest that in caiman, high levels of inspired CO2 promote slow, deep breathing. This will decrease deadspace ventilation and may reduce stratification in the saccular portions of the lung.

Mucus extravasation and retention phenomena: a 24-year study

Background: Mucoceles are benign lesions related to the minor salivary glands and their respective ducts frequently affecting oral structures which are generally asymptomatic. Mucoceles are generally characterized by swollen nodular lesions preferentially located on the lower lip and differ from the so-called ranulas, which are lesions located on the floor of the mouth and related to the sublingual or submandibular glands.Methods: The objective of the present study was to analyze data such as age, gender, race and site of the lesion of 173 mucocele cases diagnosed at the Discipline of Stomatology, Sao Jose dos Campos Dental School, UNESP, over a period of 24 years (April 1980 to February 2003).Results: of the 173 cases analyzed, 104 (60.12%) were females and 69 (39.88%) were males. Age ranged from 4 to 70 years (mean +/- SD: 17 +/- 9.53) and most patients were in the second decade of life (n = 86, 49.42%); white (n = 124, 71.68%). The lower lip was the site most frequently affected by the lesions (n = 135, 78.03%), whereas the lowest prevalence was observed for the soft palate, buccal mucosa, and lingual frenum.Conclusion: In this study, mucoceles predominated in white female subjects in the second decade of life, with the lower lip being the most frequently affected site.

The effect of L-arginine on guinea-pig and rabbit airway smooth muscle function in vitro

We have investigated the effects of L-arginine, D-arginine and L-lysine on airway smooth muscle responsiveness to spasmogens in vitro. Both L-arginine and D-arginine (100 mM) significantly reduced the contractile potency and maximal contractile response to histamine but not to methacholine or potassium chloride in guinea-pig epithelium-denuded isolated trachea. Similarly, the contractile response to histamine was significantly reduced by L-arginine (100 mM) in rabbit epithelium-denuded isolated bronchus. The amino acid L-lysine (100 mM) failed to significantly alter the contractile potency of histamine in guinea-pig isolated trachea (P>0.05). In guinea-pig isolated trachea precontracted with histamine, both L-arginine and D-arginine produced a concentration-dependent relaxation which was not significantly altered by epithelium removal or by the presence of the nitric oxide synthase inhibitor, NG-nitro L-arginine methyl ester (L-NAME; 50 µM). Thus, at very high concentrations, arginine exhibit a non-competitive antagonism of histamine-induced contraction of isolated airway preparations that was independent of the generation of nitric oxide and was not dependent on charge. These observations confirm previous studies of cutaneous permeability responses and of contractile responses of guinea-pig isolated ileal smooth muscle. Taken together, the data suggest that high concentrations of arginine can exert an anti-histamine effect.

Morphological findings in the tracheal epithelium of dogs exposed to the inhalation of poorly conditioned gases under use of an endotracheal tube or laryngeal mask airway

OBJETIVO: Avaliar as alterações morfológicas no epitélio traqueal de cães expostos à inalação de gases pouco condicionados, sob ventilação com tubo traqueal (TT) ou máscara laríngea (ML). MÉTODOS: Doze cães adultos foram divididos aleatoriamente em dois grupos: grupo TT (n-6) e grupo ML (n-6), submetidos à anestesia venosa e ventilação mecânica, em sistema sem reabsorção de CO2. Foram registrados parâmetros hemodinâmicos e ventilatórios, temperatura timpânica, temperatura, umidade relativa e absoluta do ar ambiente e dos gases inalados durante 3 horas. Ao término do experimento, os animais foram submetidos a eutanásia e realizadas biópsias ao longo do segmento traqueal para estudo morfológico. Três cães saudáveis foram utilizados para controle morfológico. RESULTADOS: A temperatura dos gases inalados manteve-se entre 24ºC e 26ºC, a umidade relativa entre 10% e 12%, e umidade absoluta entre 2 -3 mg H2O.L-1 sem diferença significativa entre os grupos. em ambos os grupos a análise histológica evidenciou processo inflamatório epitelial e congestão no córion, e a microscopia eletrônica de varredura mostrou agrupamento e desorganização ciliar. A microscopia eletrônica de transmissão detectou maiores alterações no grupo TT do que no ML, como alargamento das junções intercelulares, desorientação ciliar, vacuolização citoplasmática, alterações nucleares como pcinose e condensação da cromatina. CONCLUSÃO: A máscara laríngea determinou alterações menos pronunciadas no epitélio traqueal de cães expostos à inalação de gases pouco condicionados.