Pneumothorax refers to the presence of air between the lungs and the wall of the chest. When present, it prevents full expansion of the lungs and may result in respiratory distress of even death. A continuous pneumothorax occurs when there is a constant leak of air into the chest. Air may enter the chest either from the outside (through a defect of the chest wall) or internally (through a defect in the lungs). Pneumothorax may occur as a result of trauma, secondary to surgery, or as a result of rupture of a bulla spontaneously. Conservative management of continuous pneumothorax involves chest tube placement and continuous suction. If this fails, surgery to identify and close or remove leaking tissue has been used, however this is associated with significant cost and morbidity. Pleurodesis is a technique where the lung is adhered to the chest wall through administration of inflammatory agents such as talc or tetracycline. Blood patch pleurodesis involves administration of blood products into the chest to seal openings in the lungs and adhere the lungs to the walls.
This paper describes a case series of three cats managed for continuous pneumothorax with allogenic blood pleurodesis. It is a retrospective series of three cats presenting to a tertiary care facility for repair of diaphragmatic hernias from 2013 to 2014. The first cat had a traumatic hernia as a result of vehicular trauma, the second was detected incidentally and was of unknown origin, and the third was detected after general anesthesia and was also of unknown origin. All three cats were stable through surgery, but post operatively developed continuous pneumothorax requiring chest tube placement and continuous suction.
In each cat, management of pneumothorax with blood patch pleurodesis was elected. Due to the concerns for instability in the patients, collection of large volumes of blood for autologous blood pleurodesis was considered contraindicated. As such, type matched blood from the hospital’s donor pool was used. Whole blood, 5-10mL/kg, was freshly collected from the jugular with a 19g needle and aliquoted into 6-12 mL non-anticoagulated syringes. In-situ thoracostomy tubes were disconnected from suction, clamped, scrubbed with alcohol and chlorhexidine and injection ports replaced. Collected blood was administered into the thoracostomy tubes which were re-clamped and left disconnected from suction. Cross matching was not performed prior to allogenic blood administration.
All cats tolerated the infusion well, however they required re-aspiration of the thorax within 1-2 hours due to increased respiratory rate and effort. Resolution of pneumothorax was noted in all three cats within 24 hours. Repeated administration of blood was not needed. No adverse responses were seen to infusion of blood, and there were no transfusion reactions noted. All cats were on broad spectrum antibiotics and analgesia as a result of the preceding thoracotomy.
All cats survived to discharge and had no recurrence of clinical signs at the time of last follow-up. There were no delayed complications of blood patch pleurodesis reported.
This is the first report of the use of allogenic fresh whole blood to perform blood patch pleurodesis in cats after development of continuous pneumothorax. It suggests that, while one aspiration was still needed post administration in all cats, the procedure was well tolerated and effective.
Though this case series showed successful use to pleurodesis, it was a retrospective study in a small number of cats. Further data in a controlled, prospective manner on a larger number of cats is indicated to determine ideal doses, timing, and success rates. The volumes used in this study were proportionally much higher than those described in human medicine, and it is unclear if these large volumes are needed or helpful. The use of allogenic vs autologous blood should also be investigated. (MRK)