Autologous Blood Pleurodesis in a Great Dane with a Persistent Spontaneous Pneumothorax
Margaret F Winter
Clinical advisor: Dr. Jill DiFazio
Basic science advisor: Dr. James Flanders
Senior Seminar Paper
Cornell University College of Veterinary Medicine
April 23, 2014
Spontaneous pneumothorax—Persistent pneumothorax—Pleurodesis—Pleural port—Blood
pleurodesis—Sclerosing agents
Abstract
A spontaneous pneumothorax is the accumulation of air in the pleural space without an
inciting iatrogenic or traumatic event1. In the last decade there has been a shift from managing
canine spontaneous pneumothorax medically to managing it surgically, due to evidence that
there is recurrence in 53% of medically managed cases and only 12% of surgically managed
cases2. The need for a second-line treatment if surgery fails or is not an option has resulted in
several novel alternatives such as modified vascular access ports known as pleural ports,
autologous blood pleurodesis, and chemical pleurodesis using sclerosing agents.
Case History
A 7 year old, spayed female, Great Dane was referred to Cornell University’s Hospital
for Animals’ emergency service for further work-up and treatment of a spontaneous
pneumothorax. The patient had been boarding at a kennel when, 3 days prior to presentation, she
started to become tachypneic with increased respiratory effort. She was sent to a referral hospital,
where radiographs revealed a bilateral pneumothorax and diffuse interstitial pattern. After
thoracocentesis yielded greater than 1 liter of air from each hemithorax, the patient had bilateral
Mila chest tubes placed, was put on continuous suction, had bilateral intranasal cannulas placed
for oxygen supplementation, was maintained on IV antibiotics and analgesia over night, and was
referred to Cornell the following day. The patient’s past medical history included a GDV with
gastropexy, a left cruciate repair, severe pododermatitis, self mutilation of her left hind foot, a
suspected tachyarrhythmia, a suspected chylothorax, chronic gastrointestinal signs and a 2.5 year
history of significant weight loss.
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Clinical Findings
On presentation at Cornell, the patient was tachycardic and tachypneic with decreased
bronchovesicular lung sounds dorsally. She was under-conditioned (BCS of 3/9) with moderate,
diffuse muscle atrophy, severe medial buttress bilaterally, was short strided in all four limbs, had
all of her claws scuffed down to distal P3, and pododermatitis in all four paws. Point of care
blood work was unremarkable, her SpO2 was 97% on room air, and her tachycardia improved
after receiving 0.1mg/kg methadone IV and removing a total of 2.7 liters of air and 20 mL of
pleural effusion. In-house cytology of the effusion revealed non-degenerate neutrophils,
lymphocytes, and mesothelial cells. No further initial blood work was performed because the
prior day’s results were normal at the referring veterinarian.
The patient’s problem list included 1) bilateral spontaneous pneumothorax, 2) diffuse
pulmonary interstitial pattern on thoracic radiographs, 3) mild, sterile, suppurative pleural
effusion 4) severe generalized muscle atrophy, 5) abnormal gait, and 6) pododermatitis.
Differential Diagnoses
The differential diagnoses for canine spontaneous pneumothorax can be prioritized
somewhat by signalment. With an older, large breed patient, bullous emphysema (ruptured
bullae) and neoplasia would be the greatest concerns, with migrating foreign bodies and
infectious processes such as D. immitis, Paragonimus pulmonary cysts, and pneumonia being
possibilities as well. This patient’s diffuse pulmonary interstitial pattern was likely a result of
atelectasis, but further diagnostic tests are necessary to rule out pneumonia, hemorrhage, and
immune mediated disease. The last major thoracic problem, pleural effusion, has a large list of
differential diagnoses that requires basic fluid analysis (total protein and cell composition) to
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narrow it down. Only cytology to identify cells and bacteria was initially performed on this
patient, therefore further test results are required. The remaining problems (severe generalized
muscle atrophy, abnormal gait, and pododermatitis) were considered secondary problems that
were not explored further due to the owner’s wishes.
Diagnostic and Therapeutic Plan
After a night of stabilization and supportive care, which included fluid therapy,
continuous suction, analgesia, gastroprotectants, and anti-microbial therapy, the patient had left
stifle radiographs performed to rule out a neoplastic cause for such profound medial buttress.
The radiographs revealed osteoarthritis, so the patient was put under general anesthesia for
advanced imaging to assess the pneumothorax. Thoracic CT revealed a small amount of air in
each hemithorax, 5-6 small gas filled bullae in the right caudal lung lobe, and a narrow vertebral
canal with mild spinal cord compression at C5-6 and C6-7. Based on these results, an
exploratory thoracotomy with partial right cranial and accessory lung lobectomies was
performed and the Mila chest tubes were replaced with bilateral thoracostomy tubes.
Histopathology of the lung tissue confirmed the presence of pulmonary emphysema and
multifocal bullae- changes consistent with spontaneous pneumothorax.
Postoperative Complications- Treatment and Outcome
Postoperatively, the patient’s thoracostomy tubes were checked every 2 hours. The
patient produced a moderate amount of serosanguinous effusion and a small amount of air
intermittently. After 3 days, the patient became tachypneic again and several hundred milliliters
of air were removed from her chest. No leaks in the tubes could be found and the pleural fluid
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was submitted for analysis and culture, revealing a sterile, non-chylous, exudate with many nondegenerate neutrophils.
After four days of hospitalization, the patient’s owner wanted to treat palliatively at
home, so a pleural port was placed under general anesthesia in the left 8th intercostal space. The
following day, several hours prior to being discharged from the hospital, autologous blood
pleurodesis was performed as a final attempt to stop the persistent pneumothorax. A closed
system was created between an 18 gauge jugular catheter and a thoracostomy tube using 2
extension sets, 2 three-way stopcocks, and a 30mL syringe. 4.2mL/kg (250mL) of blood was
instilled into the right thoracostomy tube and the patient was rolled several times to distribute the
blood throughout the thoracic cavity. After this procedure, the patient’s remaining thoracostomy
tube was removed from the right chest wall, her temperature was monitored frequently, and
several hours later, without any post-procedural complications, she was discharged to the care of
her owner.
The following month after discharge from the hospital, the patient exhibited no
respiratory problems or difficulties and no need for tapping her pleural port. However, she
returned to her local veterinarian for hyperthermia (103°F), progressive weight loss, anorexia,
lethargy, and a urinary tract infection refractory to antimicrobial therapy. Initial diagnostic tests
revealed a mature neutrophilia and scant pleural effusion. Beyond this, no other information
could be ascertained and the patient was lost to follow up.
Discussion
In both human and veterinary medicine, spontaneous pneumothorax is often a recurrent
problem that lacks reliable and definitive treatment options1-3. As a result, numerous treatments
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have been utilized in varying ways and dosages, but without randomized, prospective studies
validating or refining their usage. For many years, canine spontaneous pneumothorax had been
treated according to human guidelines, which describe thoracocentesis and rest as the standard of
care2,3. However, recent studies have shown that dogs with spontaneous pneumothorax respond
to various treatment modalities differently from humans2. This is exemplified by the Puerto et al.
study, which showed that, unlike humans, dogs have a much higher rate of recurrence when
spontaneous pneumothorax is treated medically instead of surgically2. Similarly, many studies
suggest that humans are more responsive to pleurodesis than dogs and other animals based on the
much lower recurrence rates observed in humans3-6. Despite the variable efficacy seen in dogs,
several promising procedures and treatments have been adapted from human medicine, including
the pleural port, autologous blood pleurodesis, and chemical pleurodesis with sclerosing agents.
The use of pleural ports to manage persistent cases of spontaneous pneumothorax has
been described in several dogs after surgery failed7. A pleural port is similar to a vascular access
port used for chemotherapy, but it has a long, fenestrated catheter that sits in the pleural cavity.
The port is placed subcutaneously in the 7th or 8th intercostal space and is accessed with a sterile
22 gauge Huber needle through surgically scrubbed skin. This device is intended to be used as a
second line treatment if surgery has failed or is not an option. In one case report, two dogs
refractory to surgical treatment had pleural ports placed 5 days after their unsuccessful surgeries.
One of the dogs was tapped on an outpatient basis for 3 weeks, until the owner was able to
acquire the money necessary for a second surgery. Following the second surgery, the dog
survived another 17 months before recurrence of the spontaneous pneumothorax and subsequent
euthanasia. The other reported dog was tapped on an outpatient basis via the pleural port until
resolution of the pneumothorax, which occurred within two weeks. The dog continued to do well
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for at least another 23 months before being lost to follow up. In both cases, the dogs’ lives were
extended substantially as a result of using a pleural port for palliative care when surgery was
unsuccessful7. The Great Dane discussed in this case report was also, to some extent,
successfully managed with a pleural port. While it was not needed for removing air or fluid, the
port enabled the dog to go home for whatever remaining time she had left.
Autologous blood pleurodesis is another treatment alternative for persistent spontaneous
pneumothorax6,8. It is a simple and inexpensive treatment that involves taking the patient’s own
blood and putting it into the pleural space. The mechanism of action is believed to be
multifactorial and includes pleurodesis- an induced inflammatory reaction that creates adhesions
between the visceral and parietal plurae so that the pleural space is obliterated, leaving no room
for air to accumulate. However, some patients see results within minutes to hours of the
procedure, so in addition to promoting adhesion formation, it is thought that the blood acts as a
Bandaid™ and clots over the leaking bullae/blebs in the lungs8. There have been several case
reports and studies in both humans and animals that have documented the successful use of
autologous blood pleurodesis, but there are still many knowledge gaps in the technique, dose of
blood, adverse reactions, and so forth. In general, most literature suggests using 2-5mL/kg of
autologous blood for successful results3,5,8,9. A study performed on rats determined that 23mL/kg of autologous blood reliably produced adhesions, and that unsuccessful studies likely
used an insufficient volume of blood9. One such study used rabbits as the test subjects, and found
autologous blood pleurodesis to not be a successful treatment modality; however, this study used
a low dose of 1mL/kg of blood6. A case report of a dog with persistent pneumothorax was treated
successfully using 5mL/kg of blood without any adverse reactions8. Human literature cites fever
as the most common adverse reaction to autologous blood pleurodesis, but this has not been
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reported in dogs8. Despite not being reported, since it occurs with some frequency in humans, it
would be a wise practice to monitor the temperature of dogs for a few hours after the procedure.
The patient in this case report was sedated with a low dose of butorphanol, treated with
4.2mL/kg of autologous blood, rolled a few times to distribute the blood evenly, and monitored
closely for hyperthermia afterwards. She responded well to the procedure with no adverse side
effects, and her pneumothorax resolved clinically for at least a month.
One of the most common methods of pleurodesis in human medicine is chemical
pleurodesis. Sclerosing agents are put into the pleural cavity to elicit an inflammatory response,
like with blood pleurodesis. Historically, tetracycline was used most frequently, but it is no
longer available in a form conducive to pleurodesis, so other antibiotics such as doxycycline or
minocycline have been used3. Several human and animal studies have reported successful
pleurodesis with these two agents, however they are associated with more systemic effects,
severe pain, and prolonged hospitalization when compared with other pleurodesing agents such
as autologous blood and talcum powder3,6. Silver nitrate has also shown some promise based on
a rabbit study, but there were serious side effects such as hemothorax and atelectasis, so further
studies need to be conducted with this agent3.
The most effective and inexpensive sclerosing agent in humans is talcum powder3. Talc
can be instilled into the pleural space either as a slurry through a thoracostomy tube or as a
poudrage during a thoracotomy or thoracoscopy- a human prospective study comparing these
two methods found no difference in recurrence rates4. While the success of talc pleurodesis in
humans is about 87%, animals have a much more variable and unreliable response3. Studies
across several species including dogs, pigs, rabbits, and humans have found highly variable
results and ideal dose to use, suggesting that the dose of talc for pleurodesis may be species
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specific and vary from 70mg/kg up to 400mg/kg4,6. Even though it is considered the superior
agent for pleurodesis, talc is associated with greater adverse effects than blood. Chest pain and
fever are the most reported side effects, but acquired respiratory distress syndrome (ARDS) and
acute respiratory failure were reported in 0.15% of patients treated with talc poudrage3.
Conclusion
The treatment of choice for canine spontaneous pneumothorax is surgery, but if surgery
fails or is not an option pleural ports, autologous blood pleurodesis, and chemical pleurodesis are
all viable treatment options. To further elucidate which of these alternatives is best and how to
maximize their therapeutic success, more randomized prospective studies need to be conducted.
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References
1) Smith S, Byers C. Spontaneous Pneumothorax Compendium 2009; 11.3:5-11.
2) Puerto D, Brockman D, Lindquist C, et al. Surgical and non-surgical management of and
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Vet Med Assoc 2002; 220:1670–1674.
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State of the Art. Eur Respir J 2006; 28.3:637-650.
4) Jerram R, Fossum T, Berridge B, Steinheimer D, Slater M. The Efficacy of Mechanical
Abrasion and Talc Slurry as Methods of Pleurodesis in Normal Dogs. Vet Surg 1999;
28.5:322-332.
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Talc in a Rabbit Model. Ann Thorac Surg 1999; 67:917-921.
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Pneumothorax in Two Dogs. J Am Vet Med Assoc 2012; 241.4:467-471.
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pleurodesis in a dog after surgical correction of a diaphragmatic hernia. J Am Vet Med
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