Volume 10 Issue 1 • 2016

Esophageal Perforation in a Labrador Retriever See page 4

Case Study: Make Your Diagnosis See page 8

Medical Math: Constant Rate Infusion See page 16

WELCOME

A Message from Ron Morgan, President & CEO

D

r. Herold writes about the concept of power in her column this issue – what it means to her and how the idea can and should play out on the hospital floor among staff. It is interesting to consider how power plays out in a medical environment, especially one that has a lot of passion and stress like an ER/ICU setting.

Ron Morgan, CEO

One of the things I like most about DoveLewis’ evolution over the past several years is that we have worked hard not to behave like we have the power in our relationships with referring veterinarians. I remember when I joined Dove in late 2003. It was common to hear feedback that we acted and talked in elitist tones with other veterinarians. While that was surely not always the case, the feedback was consistent enough that it had to be frequent. I often heard “ivory tower” when people described our small, somewhat-rundown clinic that did indeed practice high-quality medicine. While the medicine we practiced was respected and appreciated, at times it may have lacked a tone of partnership and respect.

Today, I believe that most of our referring veterinarians would say we work much more collegially and in the spirit of partnership. This did not happen by accident. We worked to change that “ivory tower” attitude and reset our relationship with our referring veterinary partners. Our mutual patients need a continuum of care from all of us to survive the many obstacles they may encounter while in our respective care. They deserve that partnership during their much-too-brief lives. Through collaboration, communication and partnership, I hope you see in today’s DoveLewis an organization that organically grows and changes to meet the needs of our clients, patients and partners in veterinary medicine. We will continue to build on the work we’ve done these past several years so our bond grows even stronger. That willingness to grow and collaborate for the benefit of our community and patients, I believe, is what sets DoveLewis apart – that and the best ER/ICU staff in the region.

Ron Morgan President & Chief Executive Officer, DoveLewis Emergency Animal Hospital

Internal Medicine Barbara Davis, DVM, DACVIM DoveLewis’ internist Barbara Davis, DVM, DACVIM is here to provide internal medicine consultations and case management for your patients. Dr. Davis will work collaboratively with you, the primary care veterinarian, to direct the chronic care of patients referred to the internal medicine service. Additionally, with access to DoveLewis’ ICU, critical care, surgical and diagnostic imaging services, you can rest assured your patients will receive a seamless approach to internal medicine for cases requiring critical hospitalization or surgeries.

REFERRING PATIENTS TO DOVELEWIS INTERNAL MEDICINE call 503.228.7281

From the Desk of the CMO

M

Lee Herold DVM, DACVECC

any people believe that power is granted by things outside of ourselves including status, wealth and title. Power has become synonymous with control and authority. There is an understanding that acts of power must be grand gestures, or executive mandates to fit the definition of power. These narrow views imply that those not in traditional positions of power are less able to affect the course of events or change – and this is simply not true. Power is less about authority than it is about the will to make decisions for the benefit of others and the perseverance to see things through.

Anyone can feel power when they assist a stranger to change a tire on the side of the road. They can feel power when they act to help a friend, client or animal. In veterinary medicine we have the power to ease suffering with treatment, euthanasia, gentle nursing care, kind words and more. I am reminded daily that the power of DoveLewis comes from our dedicated team members. I’m sure that you also observe this within your clinics, your staff and among your fellow co-workers. I witness power enacted on the hospital floor by our newest to our most veteran staff members. I don’t need to transfer power to my staff, but need to allow them to act on the power which they already wield far more effectively than I can. I recognize and celebrate these daily acts of power and I urge everyone to seize the power!

Board of Directors President & Chief Executive Officer

Ron Morgan

DoveLewis Emergency Animal Hospital Chair

Katharine Wilson, DVM Forest Heights Veterinary Clinic Vice Chair

Carol Opfel, DVM PDX Visiting Vet, LLC Secretary

Andrew Franklin Member at Large Treasurer

Bill Rouse, CPA Kern & Thompson, LLC

Elizabeth Altermatt Herman, DVM Murrayhill Veterinary Hospital

Scott Bontempo Welsh, Carson, Anderson & Stowe

Courtney Anders, DVM Pearl Animal Hospital

Thomas Mackowiak, DVM Lee Herold, DVM, DACVECC Chief Medical Officer, DoveLewis Emergency Animal Hospital

Heartfelt Veterinary Hospital

Alexandra McLaughry, DVM Barbur Boulevard Veterinary Hospital

Maridith Rounsavell, DVM Banfield Pet Hospital

AVAILABLE AT DOVELEWIS:

Vacuum-Assisted Wound Therapy

Vacuum-assisted closure (VAC) is a type of therapy where fluid is drawn from the wound for faster, more efficient healing. This technique may be used over closed suture lines as well as over open wounds (chronic or acute). For open wounds, VAC may be a means to prepare the wound to close primarily or with a graft. It may also be used to get a granulation bed healthy enough for closure on its own. Due to the nature of cases seen at DoveLewis (trauma and complex wounds), VAC is an advantageous form of wound therapy management. This form of therapy is regarded as financially favorable compared to conventional treatments in the management of challenging wounds.

COVER PHOTO: Superhero Rema donating blood to the DoveLewis Blood Bank, accompanied by Blood Bank Director, Jill Greene, Technician Assistant, Jolie Kaner and her dad, Robert.

Steven Skinner, DVM, DACVIM Oregon Vet Specialty Clinic

Terry Taillard PepsiCo

Angelique Whitlow, CPA Talbot, Korvola & Warwick, LLP

Contact Us main 503.228.7281 backline 971.255.5990 fax 503.228.0464 online email

dovelewis.org [email protected]

DoveLewis Emergency Animal Hospital is recognized as a charitable organization under Internal Revenue Code, Section 501(c)(3). All donations are tax deductible as allowable by law. Federal Tax ID No. 93–0621534.

Volume 10 Issue 1  VetWrap 3

SURGICAL

Esophageal Perforation in a Labrador Retriever Coby Richter, DVM, DACVS

F

isher, an 11-month-old Labrador Retriever presented on emergency after sustaining a stick impalement injury. During a game of fetch, the young dog dove for the stick (Figure 1) inadvertently shoving one end deep into the back of his oropharynx. Following stick removal, he appeared in pain, was drooling (normal appearing saliva) and had a dry cough prompting a visit to DoveLewis. On presentation Fisher was quiet with a normal temperature (100.6˚ F) and respiratory rate and pattern. He was tachycardic (HR 120 bpm) with a systolic blood pressure of 130 mmHg. No ocular or nasal discharge was noted and he was no longer drooling. Subcutaneous emphysema was palpable in the cranial cervical region. The dog was given oxymorphone (0.07 mg/kg IV) and an intravenous catheter was placed in anticipation of anesthesia. An extended data base was unremarkable and he was started on ampicillin/sulbactam, maropitant and pantoprazole IV. Radiographs were obtained of his cervical and thoracic regions showing pneumomediastinum, but no pneumothorax or other significant abnormalities (Figure 2). After discussion with the owner, Fisher was anesthetized and moved to sternal recumbency for endoscopy. He was intubated routinely with no hemorrhage or injury noted in the oropharynx. A flexible videoendoscope was passed into the esophagus where Figure 1: Fisher post-surgery shown with the offending stick.

a full thickness longitudinal perforation was documented (beginning at 25 cm from the left upper canine tooth and extending approximately 3 cm). Anticipating post-surgical care, the endoscope was passed into the stomach and a 20 Fr percutaneous endoscopic gastrostomy tube (PEG tube) was placed in routine fashion. The endoscope was removed and Fisher was prepped for surgery to repair the esophageal perforation. At surgery, a 2.5 cm dorsal esophageal tear was encountered. A culture of the deep tissues was collected. An oroesophageal tube was passed to aid in visualization and manipulation of the esophagus. After lavage and debridement, the perforation was closed in two layers (3-0 Maxon simple interrupted in the mucosa/ submucosa followed by 3-0 Maxon simple continuous in the muscular and adventitial layer). A 10 Fr round Jackson-Pratt (JP) drain was placed between the esophagus and stylohyoid muscle prior to closure of more superficial tissue planes. Following skin closure, the videoendoscope was advanced again to examine the repair. No suture was visible in the lumen of the esophagus and the perforation appeared completely sealed during dilation. Fisher remained hospitalized for three days following surgery. The JP drain produced on average 2.5 ml/hr or less of serosanguinous discharge and was removed immediately prior to discharge. PEG tube feedings began 24 hours after surgery and were uncomplicated. The initial wound culture (collected at surgery) grew an Escherichia coli and Stenotrophomonas maltophilia and Fisher was maintained on amoxicillin/clavulanate for two weeks post discharge. At six days post discharge, he was re-presented after having partially consumed his PEG tube. A new PEG tube was placed endoscopically through the same stoma, and during this procedure the esophageal repair site was evaluated. The repair was intact and maintained a seal during examination and dilation. The PEG tube was removed 18 days after the initial injury at which time Fisher was doing well and was on all oral medication and feedings. He has experienced no complications since that time. Surgical repair of esophageal perforation has a higher complication rate (dehiscence, local infection, fistula and

4 VetWrap  Volume 10 Issue 1

Figure 2: Lateral radiograph of Fisher at presentation demonstrating pneumomediastinum.

stricture) than repair of other portions of the intestinal tract. Factors that impede success include contamination with foreign material, motion (during swallowing and neck movement), lack of serosa and segmental blood supply. Contamination is best dealt with by early surgical intervention and thorough lavage and culture of the deep wound. Motion at the site can be minimized (but not eliminated) by use of a gastrostomy tube and use of a neck/head harness to restrict extension. Meticulous dissection and anatomic identification during surgery to preserve existing vascular supply, coupled with control of inflammation (NSAIDs, dead space elimination, bandaging, warm/cool compressing etc.) are important to maintain tissue viability. A 2008 retrospective reported a mortality rate of 36% (5/14) in dogs with acute esophageal stick penetration. As with most surgical cases, early repair carries the best prognosis. Fisher was in the surgical suite less than a few hours after perforation. Copious lavage at surgery and providing a mechanism for the removal of wound fluid are keys to a successful repair. In Fisher’s case, the perforation was located dorsally in the esophagus which meant that dead space and potential pocketing was several tissue planes from the skin. Penrose drains may have been employed but a closed suction system is preferred for several reasons in this location. First, it allows for measurement and

analysis of fluid. This enables the clinician to make an educated decision about when to remove a drain. Secondly, motion and compression of the muscles and tissue planes superficial to the repair will not impact the effectiveness of the drain. Finally, Penrose drains not only let fluid out but are a potential ingress for bacteria which could complicate healing further. Placement of a PEG tube in this dog allowed immediate feeding while bypassing the repair site. All medications were able to be transitioned to oral forms quickly (which can be given via the PEG tube). Owner compliance with medications which can be given via the PEG tube tends to be very good (higher than with multiple oral medications). The PEG tube also allows a gentle transition back to oral feeding. Gastrostomy tubes are usually maintained at least 10 days post-placement to allow an adhesion to form between the body wall and the stomach.  DoveLewis would like to thank Fisher’s family for allowing his case to be shared with the veterinary community. Selected References 1. Doran IP, et al: Acute oropharyngeal and esophageal stick injury in forty-one dogs. Vet Surg 37:781, 2008. 2. Kyles AE: Esophagus. In Tobias and Johnston editors: Veterinary Surgery Small Animal. 2012 St. Louis, Elsevier.

Volume 10 Issue 1  VetWrap 5

COMMUNITY PROGRAMS

The Blood Bank Program at DoveLewis

A

ll too often, injured or sick animals require blood transfusions as part of their treatment and recovery. Whether necessary due to anemia, blood loss, complicated surgeries, trauma, or another cause, a transfusion can often save the life of an animal. To meet this important need, DoveLewis runs one of the largest nonprofit, volunteer-based blood banks in the United States. This blood bank not only provides plasma and blood for the treatment of animals in-house, but also blood products to veterinarians across Portland, as well as throughout the U.S. Some 125 canine and feline donors make this possible, providing the program with enough blood to conduct over 500 transfusions for cats and dogs every year – many of them lifesaving.

400 350

333

327

303

300

240

250 200 156

150 100

98

106

171

107

50 0

Last December, the program provided one such transfusion for an 8-week-old stray kitten, who was later named Milo. Severely anemic, Milo suffered from a serious flea infestation that verged on becoming fatal. He arrived at DoveLewis emaciated and showing little sign of activity. The Blood Bank program provided Milo with two transfusions. He immediately responded after the first, and fully recovered after the second. Following treatment and care the young short-hair was returned to Multnomah County Animal Services where he was fostered in the hopes of finding his forever home. These and other stories of animals getting their lives back, thanks to a blood transfusion, keep our blood bank growing. In addition, patients needing blood transfusions, like Milo, are becoming more common. In fact, the demand for animal blood products is rising due to advances in veterinary medicine and increasing treatment options for trauma and disease. With the recent addition of Internal Milo receiving a blood transfusion

383

2011

2012

2013

2014

2015

 Units Supplied to Clinics  Units Transfused at DoveLewis Medicine at DoveLewis, more blood is needed than ever before to maintain an adequate supply for community clinics and veterinary professionals. DoveLewis is dedicated to securing donations to meet this demand both in-house as well as from other clinics. To keep up, DoveLewis is actively seeking new donor volunteers – also called “Superheroes” for the lifesaving effort they support. Healthy dogs and cats who meet specific requirements can qualify for the program, which includes a host of free benefits for animals and their owners. All volunteers are blood typed and screened for infectious disease prior to giving a blood donation to ensure they are safe and healthy donors. Without the participation of these volunteers, animals in need might not be able to receive critical transfusions in time. Their continued support, coupled with the support of the animalloving community, ensures that animals requiring a transfusion will be able to receive the care and treatment they deserve. In addition to supplying in-house patients with blood transfusions, the DoveLewis Blood Bank offers a variety of blood products to local veterinarians and clinics throughout the state, tailored to meet patient and client needs. All DoveLewis blood products come with complete instructions including proper storage temperatures, transfusion set up and transfusion rates. We also include a transfusion record to help you track your patient’s stats with a reminder of how often to repeat TPRs. For questions or assistance with determining which product may best suit a particular client case, contact a DoveLewis critical care specialist by calling our DVM backline at 971.255.5990. To find out how to get a new donor signed-up to become a Superhero or other information, please contact Blood Bank Director Jill Greene at 971.255.5920 or [email protected], or visit dovelewis.org.

6 VetWrap  Volume 10 Issue 1

DoveLewis Blood Bank Helps Save Oregon Zoo’s Speke’s Gazelle Calf Oregon Zoo’s Speke’s gazelle, Juliet

Looking for blood products? As a local donor-based community blood bank, we are here to work with you for your clinic’s blood product needs. We are available 24/7 to answer any questions you may have.

Photo by Shervin Hess, courtesy of the Oregon Zoo

P

rior to the recent birth of the Oregon Zoo’s Speke’s gazelle Juliet, the veterinary team there considered the possibility that if she were rejected by her mother when born, she would need a plasma transfusion for antibody transfer. Kristin Spring, CVT, veterinary hospital manager at the zoo, had previously worked at DoveLewis, so she knew exactly where to find the resources they needed to be prepared for the arrival of the new calf. Before the gazelle’s mother Pansy gave birth, Kristin reached out to DoveLewis Blood Bank Director Jill Greene, CVT, to get the supplies she would need to obtain a blood donation from Pansy. Because the calf would need just the plasma, Jill planned to come to the DoveLewis hospital when Juliet was born to process the blood in the blood bank’s centrifuge. The DoveLewis Blood Bank only takes donations from, and provides blood for cats and dogs, so large animal blood processing is not common. Jill prepared by researching large animal blood separation and transfusion techniques. She used protocols for horse blood separation, which would work for the gazelle’s needs.

Blood Bank

When Juliet was born, it was determined that she did need a plasma transfusion so the zoo’s veterinary team jumped into action. They took blood from Pansy and called Jill to meet Kristin at DoveLewis. Jill proceeded to process Pansy’s donated blood which was later transfused to Juliet. “That’s what we do as an organization – we work hard and we save lives” said Jill. “I was happy to do it and I would certainly do it again.”

“That’s what we do as an organization, we work hard and we save lives.” – Jill Greene, Blood Bank Director

As soon as Jill was done processing the blood at DoveLewis’ Blood Bank, Kristin was able to take the fresh plasma back to Juliet. The transfusion was successful and with much love and care from the veterinary staff at the Oregon Zoo, Juliet is doing well. 

All blood products come with complete instructions, including proper storage temperatures, transfusion set up and transfusion rates. We also include a transfusion record to help you track your patient’s stats with a reminder of how often to repeat TPRs. PRODUCTS INCLUDE: Feline Packed red blood cells . . . . . . . . . $207.50 Fresh frozen plasma . . . . . . . . . . . $184.75 Frozen plasma . . . . . . . . . . . . . . . . $139.75 Whole blood . . . . . . . . . . . . . . . . . . $331.50 Matched unit . . . . . . . . . . . . . . . . . $452.00

Canine Packed red blood cells . . . . . . . . . $208.00 Fresh frozen plasma . . . . . . . . . . . $183.00 (pediatric units available) Frozen plasma . . . . . . . . . . . . . . . . $141.75 (pediatric units available) Cryoprecipitate. . . . . . . . . . . . . . . . $210.00 Cryo-poor. . . . . . . . . . . . . . . . . . . . . . $99.50 Whole blood (by request). . . . . . . . $293.25 Matched unit . . . . . . . . . . . . . . . . . $430.25 Please call ahead to ensure availability.

OTHER SERVICES & SUPPLIES: Blood typing. . . . . . . . . . . . . . . . . . . $63.50 Major crossmatch . . . . . . . . . . . . . $100.00 Filters. . . . . . . . . . . . . . . . . . . . . . . . . $20.00 (Canine, Feline and Hemo-nate) Splitting fee . . . . . . . . . . . . . . . . . . . $32.50

FOR MORE INFORMATION, PLEASE CONTACT:

Jill Greene, Blood Bank Director 971.255.5920 [email protected] Volume 10 Issue 1  VetWrap 7

INTERNAL MEDICINE

Case Study: Make Your Diagnosis Barbara Davis, DVM, DACVIM

A

n 11-year-old female, spayed Chihuahua was referred to DoveLewis for lethargy of a few days duration and marked anemia. The only remarkable findings on physical examination were very pale mucus membranes and a grade 3/6 systolic heart murmur, which had been present for years. Rectal examination did not reveal any melena or hematochezia. Laboratory findings (Table 1), included a severe macrocytic, hypochromic regenerative anemia, marked hypoalbuminemia, mild hypoglobulinemia and mild hyperbilirubinemia. Slide agglutination was negative. A pathologist review of the blood smear did not reveal any abnormal red blood cell morphology (no spherocytes, etc.) or any red blood cell parasites. Prothrombin time was slightly prolonged. A Coombs test was performed and revealed a very low titer. A FAST scan of the dog’s abdomen revealed a small amount of peritoneal effusion. A sample of the peritoneal effusion was obtained and found to be a pure transudate (TP < 0.5 g/dL, minimal cellularity). An abdominal ultrasound was performed which revealed a large homogenous splenic mass (5.34 x 3.79 cm), which was not cavitary. The remainder of the abdomen was unremarkable, aside from the previously noted peritoneal effusion.

What are your differential diagnoses? ________________________________________________________ ________________________________________________________

Can all of these findings be explained by one problem or multiple problems? ________________________________________________________ ________________________________________________________

Problem List 1. Regenerative anemia r/o hemolysis (immune mediated hemolytic anemia (IMHA), hemophagocytic histiocytic sarcoma, babesiosis, microangiopathic anemia) vs. blood loss (gastrointestinal from bleeding mass, ulceration, etc.). 2. Panhypoproteinemia r/o hemophagocytic histiocytic sarcoma vs. blood loss vs. protein losing enteropathy vs. other. 3. Hyperbilirubinemia r/o hemolysis vs cholestasis of inflammatory disease vs. (less likely) pancreatitis vs. intrahepatic cholestasis (neoplasia, etc) vs. other. 4. Peritoneal effusion r/o secondary to the hypoalbuminemia. 5. Splenic mass r/o malignant (histiocytic sarcoma, hemangiosarcoma, etc) vs. benign (extramedullary hematopoiesis,etc).

Table 1: Summary of Main Laboratory Finding

Parameter

Value

Reference Range

12.5%

38 – 55%

Reticulocyte Count

276

10 – 110 K/uL

Platelet Count

187

143 – 448 K/uL

Serum Albumin

1.1

2.2 – 3.9 g/dL

Serum Globulin

2.0

2.5 – 4.5 g/dL

Serum Cholesterol

131

110 – 320 mg/dL

Total Bilirubin

1.1

0 – 0.9 mg/dL

Prothrombin Time

13 sec

12 – 19 sec

Partial Thromboplastin Time

82 sec

59 – 87 sec

Hematocrit

Coombs Slide Agglutination Spherocytes PCV/TS

1:2 Negative None seen 12%/3.6, Icteric serum continues on page 15

8 VetWrap  Volume 10 Issue 1

Experience you can trust to care for your patients overnight.

$250 for 12-hour block in ER or ICU Dove overnight monitoring includes exam, ER or ICU monitoring as determined by a DoveLewis veterinarian with fluids, pain management – antibiotics, or oral medications as prescribed by the referring veterinarian (if indicated) and patient status lab work (if necessary).

The medical team at Frontier Veterinary Hospital is so thankful and appreciative of Dove’s overnight monitoring package and their shuttle service. We have utilized both services many times. It is such a relief to be able to send over our stable post-operative/milder medical patients and know that we don’t have to worry about them at home overnight – essentially the overnight monitoring package is an extension of our hospital’s continued care... Thank you, Dove! – Lisa Yung, DVM



main 503.228.7281 • backline 971.255.5990 • fax 503.228.0464

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Volume 10 Issue 1  VetWrap 9

Pericardiocentesis – A Review DVM

Deena Relucio, DVM

P

ericardiocentesis is a potentially life-saving therapeutic procedure commonly performed on the ER floor. Although considered relatively safe, this invasive procedure may be associated with serious complications. If left untreated, increased intrapericardial pressure can lead to compression of the atria and ventricles (cardiac tamponade) resulting in decreased cardiac output and hemodynamic compromise to the patient. Pericardiocentesis is often an emergent procedure and it is essential to efficiently and effectively communicate the suspected diagnosis, prognosis and goals of the pericardiocentesis to the client. In addition, it is important to prepare them for the potential complications, the immediate costs associated with the procedure and financial investment ahead. This review summarizes how to recognize a patient in need of pericardiocentesis and the technical approach to the procedure.

Clinical Findings A typical history may be reported as acute collapse, exercise intolerance and weakness. Patients may present in cardiac arrest or already deceased with a client-reported history of peracute onset of clinical signs. The physical exam may reveal a prolonged capillary refill time, pale mucous membranes, muffled heart sounds, tachycardia, tachypnea, dyspnea, weak pulses or pulses paradoxus (weaker pulse during inspiration with cardiac tamponade), jugular distention or abdominal distention (cranial organomegaly, ascites). Only a few of these may be present upon physical examination.

Diagnostics A brief ultrasound scan provides definitive diagnosis for pericardial effusion. Sonographically pericardial effusion will appear as an anechoic rim of fluid between the cardiac muscle walls and the hyperechoic pericardium. Diagnosis can be complicated by the presence of pleural effusion as some cases of large volumes of pleural effusion can mimic pericardial effusion. It can be helpful to look for an anechoic effusion surrounding the “floating” auricular appendage, which is indicative of fluid within the pericardium. On ECG, there may be sinus tachycardia, ventricular premature complexes, ventricular tachycardia or electrical alternans (alternating variation in the amplitude of QRS complexes with every other beat as the heart swings inside a voluminous pericardial sac). Thoracic radiographs will be distinct and demonstrate a globoid cardiac silhouette with well-defined margins and distended caudal vena cava on all views. The films may also show pleural effusion and ascites in the cranial abdomen. If only a small amount of pericardial effusion is present, it may be difficult to differentiate pericardial effusion with various other causes of cardiac silhouette

10 VetWrap  Volume 10 Issue 1

enlargement on radiographs alone. However, radiography is an important tool if your practice does not have ultrasound capabilities. The films can be used as a guide for the proposed pericardiocentesis site. On the VD/DV view, take notice which rib space has the most contact with the cardiac silhouette. A post-procedural radiograph may be helpful in identifying underlying pathology (pulmonary nodules, mediastinal mass), or pneumothorax once the majority of the fluid has been removed. Bloodwork that includes complete blood count and chemistries may be non-specific, but may show anemia, hypoproteinemia, leukocytosis, possible liver enzyme elevation, or azotemia. If time allows, a coagulation profile may be performed to check PT/aPTT in-house. This can be valuable information prior to pericardiocentesis.

Considerations Physical and diagnostic findings will be dependent on the volume of pericardial effusion, speed of accumulation, and underlying pathology. The severity of intrapericardial pressure is greater with acute and large volumes of fluid. In chronic cases, the pericardium can stretch to accommodate even large volumes without decompensating. If the patient is relatively stable and has minimal pericardial effusion based on diagnostics, it will be beneficial to have an echocardiogram performed by a cardiologist or trained sonographer as a small quantity of pericardial fluid allows for greater visualization of auricular masses. This can provide valuable prognostic information for the owner.

Preparing Your Patient and Setup Place an IV catheter in the event that emergency medications need to be administered. ECG leads should be placed to monitor and track cardiac activity during and after the pericardial tap. If possible, 2-3 people should be recruited for the procedure – the clinician who performs the actual tap, an assistant who restrains the patient, and another assistant who controls the suction under the direction of the clinician.

Equipment • Sterile prep – clippers, scrub, sterile gloves • IV catheter, depending on size of patient 18-14 g peripheral IV catheter or abbocath catheters for larger or obese dogs • 3-way stopcock • Extension set • Syringe – 20, 35, or 60 ml • Collection bowl • Red top tube and lavender top tube

Equipment for pericardiocentesis

Analgesics and Emergency Drugs The majority of patients may be very weak and will be more receptive to handling. If necessary a light sedation may be given such as butorphanol (0.1-0.3 mg/kg). Lidocaine may be used as a local anesthetic at the proposed site at 0.5-1 ml/site into the subcutaneous space and intercostal muscle layers. Anesthetize the proposed site cranial to the rib, avoiding the neuromuscular bundle and vessels caudal to the rib. Be prepared to intubate and have pre-calculated emergency drugs in case of cardiac arrest. • Lidocaine should be drawn and ready in the event of ventricular tachycardia: 2 mg/kg IV slowly (dogs), 0.25-0.5 mg/kg IV slowly (cats) • Epinephrine: high dose (0.1 – 0.2 mg/kg) and low dose (0.01 – 0.02 mg/kg) IV • Atropine: 0.04 – 0.05 mg/kg IM, IV

Procedure The patient can be placed in either sternal or left lateral recumbency depending on patient stability and comfort. Oxygen supplementation should be provided. The right hemithorax is the preferred site as this approach lessens the chance of coronary artery laceration. Additionally, the cardiac notch is larger on the right lung lobes, which reduces accidental puncture of lung parenchyma. This procedure is not without risk. However, theoretically it is possible to puncture the thin-walled right ventricle with this approach. The deoxygenated blood can have the same port wine color as typical pericardial effusion but the clinician will generally feel movement or “bounce” through the needle and the ECG will reveal disturbances in cardiac activity so it is unlikely to go unnoticed.

Clip and surgically scrub the proposed site from the second to the seventh intercostal space (ICS) from the sternum to the mid-thorax. Some clinicians prefer fenestrating the catheter to allow for better drainage. However, this may compromise the integrity of the catheter and increase the risk for breakage while inside the pericardium. If desired, two to three small 1-2 mm fenestra-tions at the distal end of the catheter can be made with a #11 blade while the stylet is still in place. Do not burr the catheter or allow the fenestrations to exceed 40% of the diameter of the catheter. In veterinary medicine, pericardiocentesis is often performed blindly. Use radio-graphs to determine the point at which the cardiac silhouette is closest to the body wall if ultrasound is not available. While monitoring the ECG, palpate for the point of maximum intensity (PMI), typically at ICS-5. Insert the catheter perpendicularly at the locally anesthetized site cranial to the rib and apply light suction. A light pop may be felt once the pleural space is entered. Fluid may be obtained if pleural effusion is present. While monitoring the ECG, slowly advance the catheter further until the needle encounters the pericardial sac. Some clinicians report feeling a “scratching” sensation, then advance another 3-4 mm until pericardial fluid is obtained. The stylet can be removed once the correct location is achieved. Hold the catheter steady, and then connect to an extension set, 3-way stopcock and syringe. The assistant can control the syringe and suction under the guidance of the clinician. It will be important to communicate if any complications are encountered, as the majority of adverse events occur during the active pericardial tap. Slight adjustments in catheter positioning can be made if the patient develops arrhythmias or negative pressure is encountered. Progress may be checked intermittently with ultrasound. Withdraw the catheter under light suction once negative pressure is obtained or if only a small amount of fluid remains. It will not be possible to remove all pericardial fluid. In most cases the puncture left behind into the pericardial sac will continue to leak out into the larger pleural space. The patient’s vital signs usually improve rapidly and dramatically due to the decreased intrapericardial pressure and increased cardiac output. Compare the aspirated effusion with peripheral blood PCV and total protein. Generally speaking, if the blood does not clot, it is likely effusion. Blood may also not clot in cases of actively bleeding tumors, atrial tears and coagulopathy. If the fluid removed clots in 1-2 minutes, it is suspicious for ventricular blood. Effusion generally has a lower PCV than peripheral blood with xanthrochromic (yellow) supernatant once spun down. Pericardial fluid can be submitted for cytologic analysis (+/culture), but it is typically not highly diagnostic for the cause of the effusion. continues on next page

Volume 10 Issue 1  VetWrap 11

continued from previous page Table 1

Type of Pericardial Effusion

Differential Diagnosis

Key features

Hemorrhagic

Heart based tumors

Older brachycephalic breed dogs

Right atrial hemangiosarcoma

Non clotting blood

Metastatic neoplasia (lymphoma)

Older large breed dogs

Idiopathic

Middle aged, large breed

Trauma Left atrial rupture

Older dogs with valvular disease

Coagulopathy (rodenticide, other) Transudate

Congestive heart failure Hypoproteinemia Sequela after repair of PPDH

Exudate

Infectious pericarditis

Coccidioidomycosis, Actinomyces, Nocardia

Suppurative pericarditis

Foreign body, Hematogenous

Considerations

Prognosis

Cats are at higher risk for complications during pericardiocentesis due to size and smaller volumes of effusion. Most respond well to medical therapy as pericardial effusion is often associated with congestive heart failure. This procedure is generally reserved for patients with severe tamponade and who are quite hemodynamically unstable. A smaller peripheral or butterfly catheter may be used in lieu of a larger gauge catheter if attempted. All the same preparations apply, but almost all cats will require more tranquilization for this procedure than dogs.

Prognosis is generally poor to guarded depending on the underlying cause (Table 1).

Complications Statistically, pericardiocentesis carries a low rate of complication in the canine patient. It is important to classify between procedural complications from progression or effects of underlying disease. In most cases, it may not be possible to distinguish the difference. Most complications associated with pericardiocentesis occur during or shortly after the procedure (