Anatomical, Cardiovascular, and Blood Gas Parameters in Dogs with Brachycephalic Syndrome

Abstract

Background: Brachycephalic syndrome is characterized by increased airflow resistance in upper airways due to the combinations of anatomical deformities such as stenotic nares, elongated soft palate, everted laryngeal saccules, and tracheal hypoplasia. There is little information in recent literature about assessment of anatomical, cardiovascular, and blood gases' parameters of these animals at early stages of the syndrome. The purpose of this study was to characterize and to compare anatomical, cardiovascular, and blood gases' parameters in young brachycephalic or dolichocephalic and mesocephalic dogs. Materials, Methods & Results:Twenty brachycephalic dogs (BG) and 20 dolichocephalic and mesocephalic dogs (CG), aged up to 5 years, were included in the study. Anatomical abnormalities, systolic (SAP), mean (MAP), and diastolic (DAP) arterial blood pressure were recorded. Blood gas analysis and complete blood counts (CBC) were analyzed. Doppler echocardiography, electrocardiography, ambulatory electrocardiography, and thoracic and cervical radiographs were evaluated. The diameter of the nares in BG was lower when compared to CG (0.23 ± 0.08 versus 0.56 ± 0.05 cm, P < 0.001). The S a O 2 was lower (P < 0.001) and MAP was higher in BG (P = 0.05). All brachycephalic dogs had sinus arrhythmia (SA), and 15 (75 %) of these showed SA higher than 20% variation between adjacent RR intervals, whereas in CG, 17 (85%) of animals presented SA and 13 (65%) of these showed SA higher than 20 % variation between adjacent RR intervals. The smallest opening of the nostril, in brachycephalic dogs, was accompanied by a lower S a O 2 and higher MAP. Results of this study suggest that young brachycephalic dogs have lower S a O 2 and higher MAP when compared with dolichocephalic and mesocephalic dogs. Discussion: The most relevant aspect of this survey was the confirmation that brachycephalic dogs have lower S a O 2 and higher MAP when compared to non brachycephalic animals. Few studies correlate upper airway obstruction to cardiovascular and blood gas alterations. Although there were no significant differences between groups for PaO2 and A a DO 2 , the means for BG were lower and higher, respectively, than CG, showing that obstruction of airways may lead to lower P a O 2 and higher A a DO 2 . In the present study, brachycephalic animals tended to have higher tHb, PCV, DAP, and MAP, and lower S a O 2 . Even with no significant differences between groups for tHb, PCV, and DAP, one can assume that young animals may not already have presented such alterations, but as the syndrome progresses, these types of abnormalities tend to develop. Hypoventilation results in significantly lower S a O 2 in these animals, as observed in this study. All brachycephalic dogs in our study had SA and 2 (10%) showed sinus pauses of 4 s and 6 s duration, which demonstrates a stimulated vagal tone. The percentage of cervical soft tissue (CST) in brachycephalic dogs was proposed in an attempt to objectively measure the soft tissue concentrated in the neck region o...

Cardiorespiratory evaluation of brachycephalic syndrome in dogs

“…In this study, stenotic nares were the most commonly observed primary alteration (86.4%) in French Bulldogs, while elongation of soft palate was documented in only 9.1% of the brachycephalic dogs. This finding contrast with data from the literature, which suggest that soft palate elongation is the most frequent primary abnormality in BS (Fasanella et al 2010, Dias et al 2016). The methodology used for the diagnosis of soft palate elongation adopted in this study did differ from cited studies, a fact that may have directly influenced the incidence of this alteration.…”

“…The difference of P a O 2 between the groups corroborates the results obtained by Hoareau et al (2012), but contrasts with the data from Dias et al (2016). The lower P a O 2 in French bulldogs may be related to respiratory distress caused mainly by stenotic nares.…”

“…For this reason it is not possible to conclude that BG animals had a larger cardiac silhouette due to cardiac remodeling attributable to BS. In contrast, Dias et al (2016) found no difference between brachycephalic and non-brachycephalic dogs in a study that included several breeds, establishing mean VHS of 9.6±0.7 specifically for brachycephalic dogs.…”

“…The methodology used for the diagnosis of soft palate elongation adopted in this study did differ from cited studies, a fact that may have directly influenced the incidence of this alteration. While in the present study the evaluation was performed by radiographic examination of the cervical region (Krebs & Marks 2007), most of previously published studies employed direct inspection of the oropharynx, with an animal in a superficial plane of anesthesia, to diagnose palatal elongation (Fasanella et al 2010, Hoareau et al 2012, Dias et al 2016.…”

Archaeological Treasures of Dolenjski muzej Novo mesto

“…Systemically healthy brachycephalic dogs have been found to have hypertension and significantly higher arterial partial pressure of carbon dioxide (PaCO2) and significantly lower arterial partial pressure of oxygen (PaO2) and arterial haemoglobin oxygen saturation (SaO2) compared to non-brachycephalic breeds (Hoareau et al, 2012;Arulpagasam et al, 2018). Significantly lower SaO2 (Dias et al, 2016;Arulpagasam et al, 2018) and PaO2 (Canola et al, 2018) were reported in brachycephalic dogs with BOAS compared to non-brachycephalic dogs. On the other hand, no significant difference in arterial pH, PaO2, bicarbonate (HCO3 -) concentration and PaCO2 was reported between BOAS-affected dogs and non-brachycephalic dogs (Dias et al, 2016;Arulpagasam et al, 2018).…”