Indication, management, and outcome of brachycephalic dogs requiring mechanical ventilation

Objectives - To evaluate the frequency, and need for mechanical ventilation (MV) in a population of brachycephalic dogs (BD) compared with non-BD. Also, to describe the pre-MV abnormalities, ventilator settings used, the cardiovascular and pulmonary monitoring results and complications encountered in the same BD population. In addition, we sought to identify factors associated with successful weaning and describe outcomes of BD requiring MV. Design - Retrospective observational study (1990-2008). Setting - University Small Animal Teaching Hospital. Animals - Fifteen BD managed with MV. Interventions - None. Measurements and Main Results - Signalment, indication for MV, ventilator settings, arterial blood gas values, duration of MV, complications, and outcome were recorded for each patient enrolled in study. BD were more likely to receive MV than non-BD (P = 0.036). Out of the 15 dogs that fulfilled the inclusion criteria 7 (47%) underwent MV for impending respiratory fatigue, 6 (40%) for hypoxemia and 2 for hypercapnea. The most common underlying disease was aspiration pneumonia. Duration of MV ranged from 2 to 240 hours (median 15 hours). Seven patients were weaned (47%). Seven dogs had a temporary tracheostomy tube and 5 of them (71%) were weaned. Dogs that were weaned had a significantly greater preweaning trial PaO(2)/FiO(2) ratio than those that were not (359 +/- 92 versus 210 +/- 57 mm Hg, P = 0.025). No significant difference for weaning success between dogs with and those without a tracheostomy was detected (P = 0.132). The discharge rate was 27% (all from the respiratory fatigue group). Conclusion - Among all dogs admitted to ICU, BD were more likely to receive MV than non-BD. Aspiration pneumonia was frequently identified as the underlying cause of respiratory compromise. The survival rate for BD undergoing MV was not markedly different from previous studies. Weaning of BD from MV may be facilitated by employing preemptive strategies such as performing tracheostomy tube placements.