Complications and outcome of traumatic diaphragmatic hernia repair without post-operative chest drain: Retrospective study in 90 cats.

Background: Diaphragmatic herniorraphy is the treatment of choice for traumatic diaphragmatic hernia (TDH). Several methods have been described for the removal of residual air and fluid during and after surgery, such as the insertion of chest drains, intercostal thoracentesis, and transdiaphragmatic thoracentesis. However, there are no indications regarding the most useful technique and the impact that choice of technique could have in the immediate postoperative period. Aim: To evaluate the development of complications and outcomes associated with the use of intraoperative transdiaphragmatic thoracentesis in cats undergoing diaphragmatic herniorrhaphy for TDH. Methods: Medical records of cats treated for acute and chronic TDH between 2010 and 2019 were reviewed. Cats were included if intraoperative pneumothorax was treated with transdiaphragmatic thoracentesis, without the use of intercostal chest drain. Outcome, intra- and post-operative complications were recorded. Results: Intraoperative and postoperative complication rates were 3.3% and 12.4%, respectively. Development of postoperative pneumothorax was associated with the presence of comorbidities (p = 0.046). The overall survival rate was 93.3%. Long-term survival had a significant association with the presence of comorbidities (p = 0.045), if the procedure was performed as an emergency (p = 0.041) or in older cats (p = 0.011). Conclusion: Intraoperative transdiaphragmatic thoracentesis could be considered an effective method for the removal of residual air after surgery for TDH, because it ensures a good outcome for the patient, with low development of complications, especially for uncomplicated cases. The presence of comorbidities, the need to perform a surgical procedure in emergency, and the age of the patient can be considered factors influencing the development of complications. Critical patient selection, based on assessment of potential risk factors for complications is warranted to understand which patient will benefit from thoracostomy tube placement.

Suspected systemic gas embolism associated with lung tissue perforation caused by a previously inserted chest drain in a dog.

OBJECTIVE: To report a case of systemic gas embolism associated with removal of a chest drain perforating a lung lobe in a dog undergoing sternotomy under general anesthesia and intermittent positive pressure ventilation. CASE SUMMARY: An 8-year-old Cocker Spaniel underwent an exploratory thoracotomy via median sternotomy for surgical management of pyothorax that was treated conservatively for 7 days prior to referral following bilateral chest drain placement. The surgical procedure consisted of a subphrenic mediastinectomy and pericardiectomy. During surgery, it became apparent that the right drain was perforating the right middle lung lobe. Sudden desaturation and rapid hemodynamic deterioration occurred after the drain was removed. A systemic gas embolism was suspected on the basis of clinical signs and results of an arterial blood gas analysis, and immediate supportive treatment was started with an adequate response. Once the surgical procedure was completed, a clear "mill wheel" sound was audible on cardiac auscultation and point-of-care cardiac ultrasound confirmed the presence of gas bubbles in the cardiac chambers. The dog recovered from anesthesia and was managed in the intensive care unit where arterial blood gas analyses were nearly normal and the dog made a full recovery. NEW OR UNIQUE INFORMATION PROVIDED: In people, there are reports of fatal air embolism related to the use of chest drains. To our knowledge, this is the first case report in dogs of a systemic gas embolism during open-chest surgery caused by a chest drain perforating a lung lobe. Immediate recognition and aggressive treatment of this life-threatening condition should be provided in order to achieve a favorable outcome.

Use of a pleural access port for the treatment of pyothorax in a cat.

Background: Pyothorax in cats is treated with intravenous fluids and antibiotics, and while thoracotomy and debridement are less commonly necessary, thoracostomy tubes are the treatment of choice when repeated drainage of the pleural cavity is needed. Case Description: An 11-month-old British short-haired cat was presented for a sudden onset of lethargy, dyspnea, and tachypnea, following an ovariohysterectomy 10 days prior to the treatment process. Pyrexia and muffled cardiac sounds on the left hemithorax were noted. A hemogram indicated the development of anemia and neutrophilia with a left shift. Radiography and ultrasonography confirmed a pleural effusion, and a CT scan ruled out the presence of any masses or perforating foreign bodies. A PCR on the pleural effusion ruled out feline coronavirus infection, and fluid analysis was confirmed as a septic exudate with Pasteurella multocida infection. A pleural access port was used to treat the pyothorax that successfully reduced hospitalization time and lowered overall financial outlay despite surgical implantation. Conclusion: The present report describes the successful use of a pleural port to treat pyothorax in one cat. This is the first time such a device has been reported for the treatment of pyothorax.

The use of small-bore wire-guided chest drains for the management of feline pyothorax: A retrospective case series.

Background: Pyothorax in cats is routinely managed, at least initially, with thoracic tube placement associated with systemic antimicrobial administration. Traditionally, large-bore trocar-type thoracostomy tubes have preferentially been used for the drainage of thick material from the pleural space. In recent years, the use of small-bore wire-guided thoracic drains has increased in both small animals and in humans. Few studies have highlighted the efficacy of small-bore wire-guided thoracostomy tubes. Aim: The purpose of this study was to describe the use of small-bore wire-guided thoracostomy tubes in feline pyothorax in terms of efficacy, safety, and outcome. Methods: Cats with pyothorax managed with small-bore thoracostomy tubes (SBTTs) (2015-2018) were retrospectively studied. The number of drains inserted, the need for anesthesia and analgesia for chest tube placement and maintenance, and related major and minor complications were reviewed. Clinical data, diagnostic results, treatment, and outcome were recorded. Results: Ten cats were enrolled. Thoracostomy tube placement was unilateral in 7/10 cats, despite the presence of bilateral effusion in 9/10 cats, and required sedation (8/10) or anesthesia (2/10). Three cats experienced minor complications during the chest tube insertion, including self-limiting pneumothorax (1/3) and malpositioning (2/3). One cat had a major complication (non-functional malposition) requiring reposition of the drain. Pain management was adequately achieved using opioids (8/10) or opioids plus nonsteroidal anti-inflammatory drugs (2/10). Partial chest tube occlusion occurred in three cases and it was resolved with lavage. In one case, the occlusion was complete, requiring drain removal. Three out of 10 cats were treated medically, combining thoracostomy tubes and antibiotics, while 7/10 cats underwent surgery. All the cats survived. Conclusion: SBTTs represent a safe and effective option for the initial management of feline pyothorax. In fact, mainly minor complications were reported during insertion and usage. The SBTTs were well tolerated by the cats with a satisfactory performance in terms of exudate drainage in most cases. The combined use of a small-bore thoracostomy drain together with the common practice of surgical treatment might have resulted in the successful management of the cases presented.

In vitro evaluation of negative pressure generated during application of negative suction volumes by use of various syringes with and without thoracostomy tubes.

OBJECTIVE: To determine the amount of negative pressure generated by syringes of various sizes with and without an attached thoracostomy tube and whether composition of thoracostomy tubes altered the negative pressure generated. SAMPLE: Syringes ranging from 1 to 60 mL and 4 thoracostomy tubes of various compositions (1 red rubber catheter, 1 polyvinyl tube, and 2 silicone tubes). PROCEDURES: A syringe or syringe with attached thoracostomy tube was connected to a pneumatic transducer. Each syringe was used to aspirate a volume of air 10 times. Negative pressure generated was measured and compared among the various syringe sizes and various thoracostomy tubes. RESULTS: The negative pressure generated decreased as size of the syringe increased for a fixed volume across syringes. Addition of a thoracostomy tube further decreased the amount of negative pressure. The red rubber catheter resulted in the least amount of negative pressure, followed by the polyvinyl tube and then the silicone tubes. There was no significant difference in negative pressure between the 2 silicone tubes. The smallest amount of negative pressure generated was -74 to -83 mm Hg. CONCLUSIONS AND CLINICAL RELEVANCE: Limited data are available on the negative pressure generated during intermittent evacuation of the thoracic cavity. For the present study, use of a syringe of ≥ 20 mL and application of 1 mL of negative suction volume resulted in in vitro pressures much more negative than the currently recommended pressure of -14.71 mm Hg for continuous suction. Additional in vitro or cadaveric studies are needed.

Fluoroscopically guided wide-bore thoracostomy tube placement: Description of the technique and comparison to blind placement.

OBJECTIVE: To describe and compare fluoroscopic guidance for placement of wide-bore thoracostomy tubes (FGTT) to traditional, blind placement of thoracostomy tubes (BPTT). STUDY DESIGN: Prospective clinical trial. ANIMALS: Twenty client-owned dogs. METHODS: Dogs requiring medical management of pleural effusion received a BPTT, whereas dogs undergoing postoperative management of pneumothorax and/or pleural fluid after lateral thoracotomy received an FGTT. Time of placement, accuracy of positioning, radiation exposure, and complications were compared between groups. RESULTS: Initial placement of BPTT took a mean of 168 seconds (range, 89-197), whereas adequate placement was radiographically confirmed at 20 minutes and 38 seconds (range, 7 minutes and 57 seconds to 39 min). Initial placement of FGTT took a mean time of 108 seconds (range, 50-341, P = .17), and adequate placement was confirmed at 125 seconds (range, 50-341, P < .001). Major errors in placement requiring removal and replacement occurred in 2 dogs for BPTT and in none for FGTT. Procedural complications did not differ between groups, and no postoperative complication occurred within the first 12 hours after placement. Radiation entrance surface dose was lower in the BPTT group (P = .004), but stochastic radiation doses did not differ. CONCLUSION: Fluoroscopic guidance of wide-bore thoracostomy tubes accelerated the time to accurate tube placement and alleviated the requirement for removal and replacement in this population. Although use of fluoroscopy increased radiation entrance surface dose, the dose was not clinically significant. CLINICAL SIGNIFICANCE: Fluoroscopic guidance of wide-bore thoracostomy tubes should be considered as an alternative to traditional, blind placement.

Comparison of the efficacy of small and large-bore thoracostomy tubes for pleural space evacuation in canine cadavers.

OBJECTIVE: To determine if there is a difference in the amounts of air (A), low-viscosity fluid (LV), or high-viscosity fluid (HV) that can be aspirated from the pleural cavity of canine cadavers using small-bore (SB) or large-bore (LB) thoracostomy tubes. DESIGN: Prospective experimental ex vivo study. SETTING: University teaching hospital. ANIMALS: Thirty-six canine cadavers. INTERVENTIONS: Each cadaver was randomly assigned to 1 of 6 groups (SB-A, LB-A, SB-LV, LB-LV, SB-HV, LB-HV). In each cadaver bilateral thoracostomy tubes (either SB or LB) were placed and 20 mL/kg of air, LV fluid, or HV fluid was instilled via 1 thoracostomy tube. Both tubes were aspirated and the volume aspirated was recorded and analyzed as a percentage of instilled air or fluid volume. The procedure was repeated on the contralateral hemithorax. MEASUREMENTS AND MAIN RESULTS: There was no significant difference in air or fluid recovery when SB and LB groups were compared. Median (range) air recovery volumes in the SB-A and LB-A groups were 101.5% (94.4-115.8%) and 102.8% (94.1-107.8%), respectively (P = 0.898). Recovery of LV fluid was 93.5% (79.2-99.0%) for SB-LV and 85.8% (77.1-101.8%) for LB-LV cadavers (P = 0.305) and recovery percentages of HV fluid were 92.6% (86.1-96.2%) and 91.4% (74.2-96.4%) for SB-HV and LB-HV groups, respectively (P > 0.999). There was no significant difference between SB and LB groups when all substances were combined (94.1% [79.2-115.8%] and 93.5% [74.2-107.8%], respectively, P = 0.557). CONCLUSIONS: SB and LB thoracostomy tubes demonstrated similar efficacy in removing known amounts of air, LV fluid, and HV fluid from the pleural space of canine cadavers. Further study is necessary to determine if SB and LB thoracostomy tubes demonstrate similar efficacy in clinical veterinary patients.

Comparison of maximum force to failure of 4 thoracostomy tube connecting devices.

OBJECTIVE: To compare the maximum force and displacement to failure of 4 different types of thoracostomy tube connecting devices. STUDY DESIGN: Experimental in vitro study. STUDY POPULATION: Four types of thoracostomy tube connecting devices (n = 10 each). METHODS: Four different connecting device configurations (10 constructs each) were tested by maximum distraction to failure using a dynamometer: (1) CTTWW-a 3-way connector with a male luer slip attached to a thoracostomy tube by a Christmas tree adapter and secured to the tube with 21 gauge orthopedic wire; (2) CTTWRCW-a 3-way connector with a male luer lock with a rotating collar attached to a tube by a Christmas tree adapter and secured to the tube with 21 gauge orthopedic wire; (3) LVSBC-a Lopez valve attached to a tube with its short-barbed connector; and (4) LVLBC-a Lopez valve attached to a tube with its long-barbed connector. RESULTS: The maximum distraction force to failure was significantly greater for CTTWRCW (250.9 N; range 143.7-293.6) than CTTWW (132.9 N; range 84.2-224.1), LVLBC (90.8 N; range 74.0-123.4), and LVSBC (54.6 N; range 39.6-164.2). The median displacement to failure of CTTWRCW (150 mm; range 54-190) was significantly longer than that of CTTWW (34.5 mm; range 22-70), LVLBC (32.5 mm; range 24-57), and LVSBC (16 mm; range 11-69). CONCLUSION: The CTTWRCW group required greater force to create failure and had a longer displacement to failure, making it a more secure choice for connection to thoracostomy tubes.

Quantification and characterization of pleural fluid in healthy dogs with thoracostomy tubes.

OBJECTIVE To quantify and characterize pleural fluid collected from healthy dogs after placement of a thoracostomy tube (TT). ANIMALS 8 healthy Coonhound-cross dogs (mean ± SD weight, 27.2 ± 1.6 kg). PROCEDURES Thoracic CT of each dog was performed before placement of a TT and daily thereafter for 7 days. Thoracic fluid volume was calculated from CT images. Effusion was aspirated when detected; volume was recorded, and cytologic analysis and bacterial culture were performed. RESULTS Mean ± SD volume of pleural effusion detected by CT was 1.43 ± 0.59 mL/kg (range, 0.12 to 3.32 mL/kg). Mean volume collected via aspiration was 0.48 ± 0.84 mL/kg (range, 0 to 2.16 mL/kg). Cytologic analysis yielded results consistent with an exudate, characterized by septic suppurative inflammation in 6 dogs and mixed inflammation in 1 dog; there was insufficient volume for analysis in 1 dog. Sufficient volume was obtained for bacterial culture for 6 dogs, which yielded pure growths of Staphylococcus pseudintermedius (n = 3) and Streptococcus equi subspecies zooepidemicus (2) and mixed growth of both of these species (1). The TT was removed before day 7 in 4 dogs because of pyothorax (n = 3) and irreversible damage to the TT (1). CONCLUSIONS AND CLINICAL RELEVANCE Presence of a TT induced a minimal volume of pleural effusion in healthy dogs. Pyothorax developed in most dogs between 4 and 6 days after TT placement. On the basis of these findings, a TT should be removed by the fourth day after placement, unless complications are detected sooner.

[Pneumothorax during right-sided nephrectomy in a heifer]. / Pneumothorax als Komplikation einer rechtsseitigen Nephrektomie bei einem Jungrind.

A 250-kg heifer had signs of colic attributable to urolithiasis of the right kidney. Medical treatment did not result in resolution of clinical signs, and nephrectomy was carried out. The surgery was started with the heifer standing, and the 13th rib was resected. However, during blunt dissection of the kidney, air suddenly entered the pleural space and the heifer had acute severe dyspnoea. The hole in the pleural cavity was sutured and a chest drain was placed. Inhalation anaesthesia was then induced and nephrectomy could be completed without further complications. The heifer was discharged 11 days postoperatively, and was healthy and had been integrated into the herd 12 months after surgery. Pneumothorax must be considered a possible complication of rib resection in right-sided nephrectomy in cattle.

Comparison of techniques for transdiaphragmatic thoracic drainage after diaphragmatic defect closure in dogs: a cadaveric study.

Four thoracic evacuation techniques for pneumothorax elimination after diaphragmatic defect closure were compared in 40 canine cadavers. After creating a defect in the left side of the diaphragm, thoracic drainage was performed by thoracostomy tube insertion through the defect and a small (DD-SP) or large (DD-LP) puncture created in the caudal mediastinum, or through both the diaphragmatic defect and intact contralateral diaphragm with a small (DI-SP) or large (DI-LP) puncture in made in the caudal mediastinum. Differences in intrapleural pressure (IPP) between the right and left hemithoraxes after air evacuation along with differences in IPP before making a defect and after air evacuation in each hemithorax were calculated. A difference (p ≤ 0.0011) in IPP between the left and right hemithoraxes after air evacuation as well as before making a defect and after air evacuation in the right hemithorax was detected for the DD-SP group. No significant differences (p ≥ 0.0835) were observed for the DI-LP, DD-LP, or DI-SP groups. Creation of a large mediastinal puncture or thoracic evacuation through both a diaphragmatic defect and intact contralateral diaphragm can facilitate proper pneumothorax elimination bilaterally after diaphragmatic defect closure in dogs with a small puncture in the caudal mediastinum.

A case of combined bilothorax and bile peritonitis secondary to gunshot wounds in a cat.

This report describes a case of bile peritonitis and bilothorax associated with diaphragmatic laceration secondary to gunshot wounds in a cat. Surgical treatment comprising cholecystectomy, placement of a chest tube for thoracic lavage and tube feeding led to an uneventful recovery. Bilothorax and bile peritonitis are a rare presentation in cats. There are only four cases reported in the literature and combined bilothorax and bile peritonitis secondary to gunshot lesion has not been documented before. This report describes positioning of the chest tube for pleural lavage through the diaphragmatic defect created by a pellet's trajectory. The tube was then allowed to exit the laparotomy incision instead of exiting the thoracic wall.

Comparison of techniques for transdiaphragmatic thoracic drainage after diaphragmatic defect closure in dogs: a cadaveric study

Four thoracic evacuation techniques for pneumothorax elimination after diaphragmatic defect closure were compared in 40 canine cadavers. After creating a defect in the left side of the diaphragm, thoracic drainage was performed by thoracostomy tube insertion through the defect and a small (DD-SP) or large (DD-LP) puncture created in the caudal mediastinum, or through both the diaphragmatic defect and intact contralateral diaphragm with a small (DI-SP) or large (DI-LP) puncture in made in the caudal mediastinum. Differences in intrapleural pressure (IPP) between the right and left hemithoraxes after air evacuation along with differences in IPP before making a defect and after air evacuation in each hemithorax were calculated. A difference (p or = 0.0835) were observed for the DI-LP, DD-LP, or DI-SP groups. Creation of a large mediastinal puncture or thoracic evacuation through both a diaphragmatic defect and intact contralateral diaphragm can facilitate proper pneumothorax elimination bilaterally after diaphragmatic defect closure in dogs with a small puncture in the caudal mediastinum.

Use of pleural access ports for treatment of recurrent pneumothorax in two dogs.

CASE DESCRIPTION: An 8-year-old castrated male mixed-breed dog (dog 1) and a 13-year-old spayed female mixed-breed dog (dog 2) were evaluated because of spontaneous pneumothorax. CLINICAL FINDINGS: Both dogs had decreased bronchovesicular sounds with coughing, tachypnea, cyanosis, lethargy, or a combination of these clinical signs. Radiographic examination revealed pneumothorax in both dogs and consolidation of a lung lobe in dog 2. Pneumothorax was alleviated following thoracocentesis in both dogs but recurred. TREATMENT AND OUTCOME: Dog 1 was initially treated by placement of a thoracostomy tube but underwent thoracotomy when pneumothorax recurred after tube removal; left caudal lung lobectomy was performed because a ruptured bulla was suspected, and a pulmonary bulla was histologically confirmed. Dog 2 underwent thoracotomy with left caudal lung lobectomy and partial removal of the left cranial lung lobe; diffuse pulmonary emphysema was diagnosed. This dog underwent a second surgery for right caudal lung lobectomy because of torsion. When pneumothorax recurred and additional surgery was not considered feasible, pleural access ports were placed in both dogs for repeated removal of air from the thoracic cavity. Ports were used clinically for 17 days in dog 1 and 14 days in dog 2. Dog 1 successfully underwent another surgery when pneumothorax recurred 18 days after port placement but was euthanized 17 months later when dyspnea and tachypnea recurred. Pneumothorax had not recurred further in dog 2 twenty-three months after port placement. CLINICAL RELEVANCE: Findings suggested that pleural access ports may have a role in the management of spontaneous pneumothorax in dogs.

Evaluation of small-bore wire-guided chest drains for management of pleural space disease.

OBJECTIVES: To evaluate the efficacy and practicality of a small-bore wire-guided chest drain for management of pleural space disease in dogs and cats. MATERIALS AND METHODS: A 14 gauge chest drain was placed using a modified Seldinger technique in animals requiring ongoing management of pleural space disease. A questionnaire was used immediately after placement to collect data regarding the ease of placement, reliability and function of the drain. RESULTS: Twenty animals were enrolled in which 29 drains were placed. The most common pleural space disease encountered was pyothorax (10 of 20). Sixteen animals required sedation for placement, and 25 of 29 chest drains were inserted at the first attempt. Most drains were placed in less than 10 minutes. The median length of time of catheter use was three days. Few complications were noted during the insertion and throughout the use of the drains. Clinicians rated drain placement as "easy" in 27 of 29 times and the drain function as "good" in 24 of 29 times. CLINICAL SIGNIFICANCE: Small-bore wire-guided chest drains are an effective alternative to larger gauge drains. Only minor complications were seen during insertion of the chest drains, and their performance was deemed satisfactory in most cases.

Use of vascular access ports with intrathoracic drains for treatment of pleural effusion in three dogs.

CASE DESCRIPTION: 3 dogs (9 to 12 years old) were evaluated because of recurrent pleural effusion that was refractory to treatment of the underlying cause. CLINICAL FINDINGS: Dogs were evaluated because of cough, dyspnea, tachypnea, or lethargy or a combination of these clinical signs. Radiography, ultrasonography, or thoracocentesis were used to confirm the presence of pleural fluid in each dog. A neoplastic cause of pleural effusion was confirmed in 2 dogs. In 1 dog, fasciitis of the mediastinum and the left parietal pleura was diagnosed, with no evidence of neoplasia. TREATMENT AND OUTCOME: Each dog was anesthestized, and thoracotomy was performed with manual perforation of the mediastinum. Permanent, subcutaneously placed vascular access ports were attached to intrathoracic, Jackson-Pratt drain tubing for repeated drainage of pleural fluid. Drains were used successfully in the 3 dogs for periods of 6 weeks, 11 weeks, and > 3 years. CLINICAL RELEVANCE: Findings suggest that subcutaneous vascular access ports attached to intrathoracic drain tubing may be an effective way to remove recurrent pleural effusion in dogs.

The efficacy of mechanical abrasion and talc slurry as methods of pleurodesis in normal dogs.

OBJECTIVE: To determine the efficacy of mechanical abrasion and talc slurry as methods for pleurodesis in normal dogs. STUDY DESIGN: Experimental study. ANIMALS OR SAMPLE POPULATION: Ten normal beagle dogs. METHODS: Group I dogs had mechanical abrasion (MA) of the pulmonary and costal pleurae performed in one hemithorax with a dry gauze sponge with a median sternotomy approach. Group II dogs had 100 mL of a 1 g talc slurry (TS) administered into one hemithorax through a tube thoracostomy. Administration of the TS was visualized by using video thoracoscopy. All dogs were evaluated at 2, 10, 20, and 30 days postoperatively by means of thoracic radiography and ultrasonographic thoracic wall measurement. The dogs were euthanatized 30 days postoperatively and a gross necropsy was performed. Hemithoraces were assigned a pleurodesis score (0-4) and an obliteration grade (0-6). Tissues were collected for histopathologic examination of pulmonary pleura, costal pleura, and pleural adhesions. Pulmonary and costal pleurae were graded for the degree of fibrosis (0-4). RESULTS: Obliteration grade and costal pleural fibrosis score were significantly higher for the treated sides in the MA dogs compared with the TS dogs. MA Dogs: Mechanical abrasion dogs had pleurodesis, obliteration, and pleural fibrosis scores that were greater on the treated side than the untreated side, however, the differences were not statistically significant. Only two MA dogs had firm adhesion of the pulmonary pleura to the costal pleura in portions of the cranial and middle lung lobes in the treated hemithorax. Thoracic wall surface area covered with adhesions was 15% and 21% in each of these two dogs. The median pulmonary pleural fibrosis score of all MA dogs for the treated hemithorax was 3 compared to 0 on the untreated side. TS Dogs: There was no statistical difference for pleurodesis scores and obliteration grades between the treated and untreated sides. No dogs showed evidence of pulmonary to costal pleural adhesions. Histopathology showed talc crossover into the untreated side in all five dogs. Median pulmonary fibrosis score of the treated hemithorax was 1 compared with 0 on the untreated side. CONCLUSIONS: Neither method of pleurodesis produced sufficient pleural adhesions to obliterate the pleural space. It is possible that the degree of pulmonary pleural fibrosis present in MA dogs may be sufficient to limit air leakage from pulmonary blebs and bullae resulting in successful treatment of spontaneous pneumothorax.

Pneumothorax secondary to Dirofilaria immitis infection in two cats.

Dirofilariasis was diagnosed in 2 cats with spontaneous pneumothorax. One cat had a 3-week history of a cough, and the other had an 11-month history of vomiting and tachypnea. Pneumothorax was managed in cats by thoracocentesis and supportive care. Diagnosis of dirofilariasis was made on the basis of heartworm antigen and antibody test results and radiographic findings. Clinical signs of heartworm infection improved after treatment with corticosteroids. Cats had good extended outcomes. Heartworm disease should be one of the differential diagnoses considered in cats with spontaneous pneumothorax.