Long-term clinical outcomes following surgery for spontaneous pneumothorax caused by pulmonary blebs and bullae in dogs - a multicentre (AVSTS Research Cooperative) retrospective study

Significance of incidentally identified bullae and blebs on thoracic computed tomography and prevalence of subsequent pneumothorax in dogs

OBJECTIVE

To determine the prevalence of incidentally found pulmonary bullae and blebs (PBBs) in a population of dogs undergoing thoracic computed tomography (CT) for reasons other than presence of pneumothorax and to determine the prevalence of subsequent spontaneous pneumothorax (SP) development.

STUDY DESIGN

Retrospective study.

ANIMALS

A total of 30 dogs.

METHOD

A total of 2221 CT studies of the sample population were retrospectively assessed for the presence of incidental PBBs between April 2013 and April 2019. Inclusion criteria were complete thoracic CT studies from dogs obtained from the hospital database. Exclusion criteria were concurrent presence of a pneumothorax or severe pulmonary disease preventing assessment for PBBs, an air-filled space related to a pathological process, for example, neoplasm, incomplete CT studies, or no available follow-up. Long term outcome was evaluated using a questionnaire to determine the occurrence of SP post CT examination.

RESULTS

Incidental PBBs were identified in 30 out of 2178 (1.4%) CT studies that met the inclusion criteria. None of the dogs subsequently developed clinical evidence of SP (median follow-up time 1255 days, range: 147 to 2363 days). One dog died suddenly of unknown cause and as no post-mortem was performed SP could not be ruled out.

CONCLUSION

There was a low prevalence of incidentally found PBBs in dogs. None of the dogs followed over a long period subsequently developed SP.

CLINICAL SIGNIFICANCE

Based on this study, prophylactic removal of lung tissue containing incidentally found PPBs is not justified.

Thoracic CT incidental pulmonary bullae in dogs: Characterization, interobserver variability, and general anesthesia risks

Ruptures of pulmonary blebs and bullae are the most common cause of spontaneous pneumothorax in dogs. Incidental bullae/blebs have been documented in otherwise healthy people, however information for veterinary patients is currently lacking. Objectives of this retrospective, observer agreement, analytical study were to characterize incidental bullae in thoracic CT studies of dogs, assess interobserver variability for characterizing the bullae, and assess anesthesia risks. Inclusion criteria were dogs presenting for non-pneumothorax related reasons that had a thoracic CT at a single specialty and emergency hospital from 2012 to 2021 and had a bulla listed in the CT report. Medical records for dogs meeting inclusion criteria were reviewed to collect data on signalment, weight, total number of general anesthesia procedures 2 years prior and 2 years following the CT scan, and adverse anesthesia events. In addition, the CT images were reviewed by three American College of Veterinary Radiology-certified veterinary radiologists to collect data on the location, size, number of bullae and thickness of the bulla wall. A total of 1119 dogs met initial inclusion criteria and 74 dogs were included in analyses. There was no sex predilection for incidental pulmonary bullae. Bullae were more commonly found in older (median age 11.3 years), large breed dogs (median weight 20.7 kg). A solitary bulla of less than 1 cm was the most common finding with no apparent predilection for a particular lung lobe. There was strong correlation among the three radiologists for bulla location, size, and number, but weak correlations for bulla wall thickness. No adverse anesthesia events were found following CT anesthesia or following repetitive anesthesia procedures.

Allogenic blood patch pleurodesis for management of pneumothorax in a Cavalier King Charles Spaniel puppy with multiple pulmonary blebs and bullae

A 9‐week‐old male intact Cavalier King Charles Spaniel was presented for evaluation of acute onset dyspnea caused by left‐sided pneumothorax. Thoracic computed tomography (CT) identified multiple pulmonary bullae and blebs in multiple lung lobes. Rupture of ≥1 pulmonary blebs or bullae, precipitated by low impact trauma, was the suspected cause of pneumothorax. A volume of 7.5 mL/kg of fresh whole blood was collected from a type‐matched donor dog and administered into the left pleural space using a thoracostomy tube. The pneumothorax was successfully resolved and no adverse effects of blood patch pleurodesis were noted. The dog was clinically normal 12 months later.

Spontaneous Pneumothorax: Management and Prognosis

This review article will review treatment and prognosis of spontaneous pneumothorax in dogs and cats. The advantages of surgical and medical management in dogs and cats, as well as current treatment practices, including autologous blood pleurodesis and small-bore chest tubes, will be discussed.