Hypoventilation After Placement of an External Splint in a Cat With Severe Pectus Excavatum Managed With Pressure Support Ventilation

OBJECTIVE: To describe the first reported case of postoperative hypoventilation in a cat following pectus excavatum correction, with a focus on the use of mechanical ventilation for its management. CASE SUMMARY: A 20-week-old male Maine Coon cat (3.5 kg) was presented with a 2-day history of lethargy, decreased appetite, and increased respiratory effort. Physical examination revealed mild tachypnea and marked caudal sternal depression. Computed tomography confirmed a severe caudal pectus excavatum associated with thoracic lordosis and a significant reduction in dorsoventral thoracic diameter. Surgical correction was performed 2 weeks later using an external splint. Postoperatively, the patient developed persistent hypoventilation requiring mechanical ventilation. Total intravenous anesthesia and assisted ventilation modes were employed. Daily spontaneous breathing trials were performed to assess ventilatory improvement, leading to successful extubation after 73 h of mechanical ventilation. The external splint was removed 6 weeks later, with resolution of clinical signs and notable radiographic improvement. NEW OR UNIQUE INFORMATION: To the authors' knowledge, this is the first documented case of hypoventilation as a complication following surgical correction of pectus excavatum in a cat. Postoperative hypoventilation may have been caused by a sudden alteration in thoracic volume due to splint application, compounded by diaphragmatic dysfunction secondary to the preexisting severe thoracic malformation. The use of a light anesthetic protocol in conjunction with pressure support ventilation may have promoted the recovery of respiratory muscles function. Daily spontaneous breathing trials were essential for monitoring ventilatory function and preventing premature weaning attempts.