The English bulldog: a natural model of sleep-disordered breathing

Abstract

To establish a natural model of sleep-disordered breathing, we investigated respiration during wakefulness and sleep in the English bulldog. This breed is characterized by an abnormal upper airway anatomy, with enlargement of the soft palate and narrowing of the oropharynx. During sleep, the animals had disordered respiration and episodes of O2 desaturation. These were worst in rapid-eye-movement (REM) sleep, with most bulldogs having O2 saturations of less than 90% for prolonged durations. In contrast, control dogs never desaturated. In REM sleep, the bulldogs had episodes of both central and obstructive apnea, the latter being associated with paradoxical movements of the rib cage and abdomen. During wakefulness, the bulldogs were hypersomnolent as evidenced by a shortened sleep latency (mean of 12 min compared with greater than 150 min for controls). This animal model should facilitate studies of the natural history of the sleep apnea syndrome and its complications.

The Anatomy of the Dog Soft Palate. II. Histological Evaluation of the Caudal Soft Palate in Brachycephalic Breeds With Grade I Brachycephalic Airway Obstructive Syndrome

“…In conclusion, by description of microscopic lesions, this study validates the gross findings of a ''long, thick, redundant and/or, hyperplastic'' soft palate, which was clinically reported in brachycephalic dogs affected by BAOS (Hendricks et al, 1987;Wykes, 1991;Hendricks, 1992;Dupré et al, 2005). According to our findings, brachycephalic soft palate is characterized by variable microscopical features that contribute to the increased thickness since the earliest Grade of the respiratory syndrome, which affects most part of the individuals belonging to these breeds during their postnatal life.…”

“…Soft palate abnormalities have been pointed out as fundamental components of BAOS, however, the anatomical bases of soft palate thickening, which is considered as one of the factors implicated in nasopharyngeal obstruction, have not been investigated on a microanatomical basis in brachycephalic dogs (Aron and Crowe, 1985;Hendricks et al, 1987;Harvey, 1989;Hendricks, 1992;Dupré et al, 2005). According to our study, conspicuous microscopic features characterized most tissue components of brachycephalic soft palate that account for the enlarged width and thickness of the organ.…”

“…Inspiratory effort occur in brachycephalic dogs since the beginning of their postnatal life, even if no or mild clinical signs are present (Hendricks et al, 1987). Features like acanthosis and reduction of connective tissue papillae have been invoked as possible contributory factor to upper airway collapsibility in human patients with OSA (Paulsen et al, 2002).…”

“…However, there is evidence that also the cranial portion of the soft palate may be implicated in airway obstruction in brachycephalic dogs (Hendricks et al, 1987). An additional drawback could be that in this study we enrolled only brachycephalic dogs diagnosed Grade I BAOS.…”

“…The thick, redundant, and hyperplastic appearance of soft palate in brachycephalic breeds has been macroscopically and clinically described (Aron and Crowe, 1985;Hendricks et al, 1987;Wykes, 1991). Although histology of the soft palate in the average dog's head has been generically described (Evans, 1993), and was analytically reported by us in the companion article dealing with the mesaticephalic dog breeds (Arrighi et al, 2011), no microanatomical studies on the brachycephalic dog soft palate seem to be available.…”