Prospective evaluation of outcome of dogs with intrahepatic portosystemic shunts treated via percutaneous transvenous coil embolization.

OBJECTIVE: To report outcome and complications after percutaneous transvenous coil embolization (PTCE) and evaluate the clinical, laboratory, and imaging changes in dogs with intrahepatic portosystemic shunts (IHPSS) pre-PTCE and post-PTCE. STUDY DESIGN: Prospective clinical trial. ANIMALS: Twenty-five dogs (15 dogs in imaging subgroup) with IHPSS. METHODS: Clinical signs, hematologic, and biochemical parameters were recorded before and 3 months after PTCE. All dogs received the same medical treatment and underwent PTCE. In the imaging subgroup, ultrasonography, hepatic portal scintigraphy, and computed tomography-angiography were performed pre-PTCE and post-PTCE. RESULTS: All evaluated bloodwork values improved by at least 50% of their initial value, by 3 months post-PTCE. Liver volume increased after PTCE (P = .001), but remained lower than normal in 11/15 dogs. Hepatic arterial fraction decreased after PTCE (P = .029), consistent with increased portal blood flow to the liver. Twenty-four of 25 dogs were available for reevaluation at 3 months, and all abnormal clinical signs had resolved in 22/24 dogs. CONCLUSION: PTCE appears promising as a treatment for IHPSS, as clinical signs resolved in most cases, bloodwork abnormalities often normalized, and the procedure was performed safely with minimal complications. PTCE increased hepatic portal perfusion and liver volume in most dogs. These promising results justify a future randomized clinical trial comparing PTCE, other attenuation options, and medical management alone.

Postoperative Hemostasis Monitoring and Management.

Although postoperative hemorrhage is an understood sequela, surgery also elicits an inflammatory response that may result in a hypercoagulable state and risk for venous or arterial thromboembolism. Postoperative venous thromboembolism is well documented in humans and is multifactorial in nature; however, evidence for its presence in veterinary medicine remains sparse. There is no consensus on the ideal type, dose, and duration of thromboprophylactic therapy in the perioperative period. Regardless, coagulation perturbations secondary to surgical stress are important considerations for the perioperative patient to reduce the possible fatal risks of hemorrhage or thrombosis.

Central venous blood gas and acid-base status in conscious dogs and cats.

To determine the reference level of central venous oxygen saturation (ScvO2) and clinical efficacy of central venous blood gas analysis, partial pressures of oxygen and carbon dioxide, pH, oxygen saturation, base excess (B.E.) and HCO3 concentration were compared between simultaneously obtained central venous and arterial blood samples from conscious healthy 6 dogs and 5 cats. Comparisons between arteriovenous samples were performed by a paired t-test and Bland-Altman analysis. Between arteriovenous samples, B.E. showed good agreement, but there were significant differences in other parameters in the dogs, and no good agreement was detected in cats. The ScvO2 in dogs and cats were 82.3 ± 3.5 and 62.4 ± 13.5%, respectively. Central venous blood gas analysis is indispensable, especially in cats.

Use of tissue plasminogen activator in catheters used for extracorporeal renal replacement therapy.

BACKGROUND: Intraluminal thrombosis of central venous catheters used for renal replacement therapy (RRT) decreases the ability to provide adequate treatment. Alteplase is a recombinant tissue plasminogen activator that has been used to improve the function of catheters used for RRT in humans. OBJECTIVES: To retrospectively review alteplase instillation in dysfunctional catheters used for RRT in dogs and cats. ANIMALS: Seventeen dogs and 8 cats receiving RRT for kidney failure. METHODS: Medical records of patients in which alteplase was used for RRT catheter dysfunction from 2004 to 2012 were retrospectively reviewed to characterize reasons for use, improvement in function, increase in blood flow, and duration of improvement. RESULTS: Alteplase was instilled 43 times in 29 catheters, most commonly because of suspicion that the catheter would not provide sufficient flow on the next treatment (n = 21). The second most common reason was inability to start a dialysis treatment (n = 12). Catheter function improved after alteplase instillation in 34 of 43 treatments (79%). Median blood flow rate increased by 13% (18 mL/min) in the dialysis session after alteplase instillation. Seven of 29 catheters (24%) were treated with alteplase on >1 occasion (median time to second treatment, 8 days), and 1 catheter had to be replaced because of intractable dysfunction. CONCLUSIONS AND CLINICAL IMPORTANCE: Alteplase is effective at improving function of central venous catheters used to provide RRT, but the results are short-lived.

Percutaneous medial saphenous artery approach for Swine central artery access.

A percutaneous medial saphenous artery catheterization technique for swine femoral access is described. The medial saphenous artery is accessed with a 22-gauge catheter-over-needle assembly, followed by 4-Fr 10-cm sheath insertion using the Seldinger technique. The 4-Fr sheath is subsequently exchanged over a 0.035-inch guidewire for a 5-Fr sheath to establish central artery access. The technique was applied to seven vessels in five swine, with successful catheterization in five vessels. The reason for failure was technical difficulty in one case and vasospasm in the other. Central artery access was still possible through direct exposure and puncture of the medial saphenous artery or the femoral artery. This technique may provide an alternative option for central artery access in swine. However, improvement in more reliable catheterization is warranted.

Carotid artery pseudoaneurysm in a cat.

UNLABELLED: CLINICAL SUMMARY: A 4-month-old female intact domestic shorthair cat presented to Kansas State University Veterinary Medical Teaching Hospital for investigation of a large, firmly adhered mass in the left mid-cervical region that developed after phlebotomy performed at the referring veterinarian's clinic. Ultrasound examination of the mass revealed a cystic structure in communication with the left carotid artery, with bidirectional blood flow through the area. A diagnosis of pseudoaneurysm secondary to accidental needle penetration of the carotid artery during jugular venepuncture was made. OUTCOME: Strict cage rest and pain management resulted in complete resolution of clinical and ultrasonographic signs in this cat.

Influence of lung injury on cardiac output measurement using transpulmonary ultrasound dilution: a validation study in neonatal lambs.

BACKGROUND: Transpulmonary ultrasound dilution (TPUD) is a promising method for cardiac output (CO) measurement in severely ill neonates. The incidence of lung injury in this population is high, which might influence CO measurement using TPUD because of altered lung perfusion. We evaluated the influence of lung injury on the accuracy and precision of CO measurement using TPUD in an animal model. METHODS: In nine neonatal lambs, central venous and arterial catheters were inserted and connected to the TPUD monitor. Repeated lavages with warmed isotonic saline were performed to gradually induce lung injury. CO measurements with TPUD (COtpud) were compared with those obtained by an ultrasonic transit-time flow probe around the main pulmonary artery (COufp). An increase in oxygenation index was used as an indicator of induced lung injury during the experiment. Post-mortem lung injury was confirmed by histopathological examination. RESULTS: Fifty-five sessions of three paired CO measurements were analysed. The mean COufp was 1.53 litre min(-1) (range 0.66-2.35 litre min(-1)), and the mean COtpud was 1.65 litre min(-1) (range 0.78-2.91 litre min(-1)). The mean bias (standard deviation) between the two methods was 0.13 (0.15) litre min(-1) with limits of agreement of ±0.29 litre min(-1). The overall percentage error was 19.1%. The accuracy and precision did not change significantly during progressive lung injury. Histopathological severity scores were consistent with heterogeneous lung injury. The capability to track changes in CO using TPUD was moderate to good. CONCLUSIONS: The accuracy and precision of CO measurement using TPUD is not influenced in the presence of heterogeneous lung injury in an animal model.

Comparison of corticosterone responses to acute stressors: chronic jugular vein versus trunk blood samples in mice.

A commonly used method for obtaining blood samples from mice is decapitation. However, there is an obvious need for repeated blood sampling in mice under stress-free conditions. Here, we describe a simple technique to repeatedly collect blood samples from conscious, freely moving mice through a chronically implanted jugular vein catheter. Furthermore, we compare plasma corticosterone (CORT) concentrations in samples obtained through the catheter 1 day after surgery with samples taken from trunk blood obtained under basal or acute stress conditions. CORT concentrations in repeated 100-µl venous blood samples were found to be similar to trunk blood samples both under basal conditions and after stressor exposure collected at identical time points (at 5, 15, and 60 min). Using both techniques, we demonstrate a progressive increase in CORT levels until 15 min after termination of stressor exposure and a decrease towards baseline values 60 min later. Anxiety-related behavior, as assessed on the elevated plus maze 3-4 days after surgery, did not differ between catheterized and non-catheterized mice. Our results provide evidence for application of jugular vein catheterization as a technique for repeated blood sampling in conscious laboratory mice. Use of this technique will greatly reduce the number of animals required for experiments involving endocrine endpoints.

Percutaneous external jugular vein catheterization in piglets using a triangulation technique.

Chronic jugular vein or central venous cannulation is routinely performed in human and animal patients for access to blood circulation. In mature swine, chronic catheter placement techniques have typically involved venous isolation via extensive cut-down, blunt dissection and manipulation of ventral neck tissues prior to catheter placement. More recently, guide-wire-assisted percutaneous techniques have become standard practice in human and veterinary medicine due to the minimization of soft tissue and vessel damages. Laboratory animal piglets are becoming more popular research models because of their immature immunological system, ease of handling and costs. However, external jugular veins are very difficult to catheterize in paediatric animals including freshly weaned piglets. The objective of this study was to develop a simple, safe and efficient method for external jugular vein cannulation in young piglets. In total, 20 piglets were anaesthetized and percutaneously catheterized with a guide-wire technique using palpable anatomical landmarks and triangulation. With this minimally invasive catheterization, it has allowed our veterinarians and veterinary technicians to quickly and easily obtain central venous access in piglets undergoing operative procedures.

Gross and histopathological observations of long-term catheterized vessels in experimental sheep.

Chronic indwelling central vessel catheters provide vascular access for compartmental infusion or sampling. However, complications with catheter patency during the postoperative and/or experimental period often arise. In order to identify physiological occurrences common with such complications, 10 multicatheterized sheep (61.8 +/- 7.8 kg BW), obtained from a previous nutrient flux study were used for gross and histopathological investigation. Catheters had been surgically placed in a hepatic portal vein (PVC), a hepatic vein (HVC), a distal mesenteric vein (MVC) and a mesenteric artery (MAC). In the previous study, catheters (PVC, HVC and MAC) were used to collect blood samples or infuse (MVC) p-aminohippurate. Catheters were maintained for a total of 58 days prior to necropsy. Histopathological findings indicated that catheter failures were associated with the following tissue responses: (i) thromboses with frequent focal vasculitis; (ii) euplastic tissues associated with extensive fibrosis; (iii) granulomas; (iv) neo-vascularization of the media; (v) calcification processes; and (vi) micro-abscesses. Additional studies are needed that address and incorporate improvement of catheter design and placement to minimize irritation of endothelium, improvement of catheter treatments and therapeutic regimes, and development and use of alternative anti-coagulants. A greater understanding of the mechanisms leading to failure will help researchers improve catheter performance and patency.

Adverse effects of EMLA (lidocaine/prilocaine) cream and efficacy for the placement of jugular catheters in hospitalized cats.

EMLA is a lidocaine/prilocaine cream used for topical analgesia in human pediatric patients. The purpose of this study was to establish the safety of EMLA in clinically ill cats, to measure systemic absorption and to determine whether EMLA reduced the need for sedation for the placement of jugular catheters. Thirty-one cats were randomized to either a placebo or EMLA cream group. Cream was applied to a 10 cm(2) area over the jugular vein, with 1h of occlusive dressing. Neither anesthetic was systemically absorbed in any cat, and no adverse clinical signs were observed. Struggling during catheter placement was less in the EMLA-treated cats compared to placebo, but did not reach significance (P = 0.06). Jugular catheters were successfully placed in 60% of EMLA-treated cats and 38% of placebo cats; this difference was not statistically significant and may not justify the added steps of EMLA cream administration for this purpose. However, EMLA does appear to be safe in clinically ill cats, and may be useful for other applications such as for skin mass removal or repeated venepuncture.

The cannulation of the caudal caval vein through the femoral vein in the pig for endocrine research.

The present study was designed to examine the usefulness of cannulation of the caudal caval vein through the femoral vein for the measurement of hormone concentrations in the reproductive tract in the pig. The experiment was performed on sexually pubertal gilts (Polish Large White x Polish Landrace) of a similar age (7-8 months) and body mass (100-110 kg) after two controlled subsequent estrous cycles. Six gilts in the luteal phase (10th day) of the estrous cycle were used in this experiment. The animals were subjected to a surgical procedure which included:--premedication (Combelen, i.m. 1 ml/10 kg of body mass) and than after 20-30 min general anaesthesia (Vetbutal, i.v., dose 30-40 ml) according to body mass and the symptoms observed,--insertion of cannulas (o.d. 2.2 and i.d. 1.8 mm)--one into the jugular vein and the other into the caudal caval vein through the femoral vein. In several gilts the cannulas were inserted into the caudal caval vein to a depth of 14, 18, 20, 23, 25 and 30 cm from the femoral ring. The concentrations of progesterone (P4) and testosterone (T) were analysed in samples of blood plasma from the jugular and caudal caval veins by radioimmunoassay (RIA). The largest differences in hormone concentrations between the jugular and caudal caval veins were ascertained when a cannula was inserted into the caudal caval vein to a depth of 20 cm from the femoral ring. In other cases the differences were less prominent, or no differences were observed (e.g. 14 cm for progesterone and testosterone or 18 cm for testosterone).

A minimally invasive percutaneous technique for jugular vein catheterization in pigs.

The objective of this study was to develop a simple, safe, reproducible, and efficient technique that used readily available commercial materials for percutaneous catheterization of an external jugular vein in the pig. Guidewire-assisted vascular cannulation was introduced in the early 1950s and is often called the Seldinger technique, after its inventor. With few modifications, this technique has become widely used for all types of vascular cannulation in human and veterinary patients. The technique has the advantage of minimizing damage to soft tissues and blood vessels. We adapted this procedure by using five anatomical landmarks to target and catheterize the external jugular vein in pigs. Percutaneous catheterization of the external jugular vein can be accomplished easily in most pigs by using this technique. Novice technicians were able to quickly and easily learn the procedure.

A simple procedure to secure an indwelling jugular vein catheter to the neck of cattle for repeated blood sampling.

A procedure to secure a jugular vein catheter system to the neck of cattle is described. A wide-mouthed polypropylene bottle attached to a halter strap provided a secure container for the catheter. This device allowed convenient access to the catheter for repeated sampling and, apparently, reduced discomfort to the cattle.

Clinical manifestations and associated disease syndromes in dogs with cranial vena cava thrombosis: 17 cases (1989-1996).

OBJECTIVE: To characterize cranial vena cava thrombosis in dogs with regard to signalment, clinical manifestation, potential inciting causes, treatment, and outcome. DESIGN: Retrospective study. ANIMALS: 17 dogs with a cranial vena cava thrombus. PROCEDURE: Medical and necropsy records were reviewed for signalment, potential causes of thrombus formation, diagnosis, clinicopathologic findings, treatment, and outcome. RESULTS: A signalment predisposition was not found. Ten dogs had cranial vena cava syndrome, and 10 had a pleural effusion. Ten dogs were dyspneic, and 5 had palpable jugular thrombi. Predisposing conditions identified were presumed immune-mediated hematologic disease and corticosteroid administration (6 dogs), sepsis (6), protein-losing nephropathy (2), neoplasia (2), and cardiac disease (1). Central venous catheterization was implicated as a contributing cause. Thrombocytopenia was the most consistent clinicopathologic finding, and ultrasonography was helpful in confirming the diagnosis. Treatment varied, but 15 of the 17 dogs died or were euthanatized within 20 days of clinical manifestation of the thrombus. At necropsy, thrombi were found in other organs, mainly the right atrium, jugular veins, and pulmonary arteries. CLINICAL IMPLICATIONS: Prognosis is poor for dogs with cranial vena cava thrombosis associated with clinical signs. Use of central venous catheters should be avoided in dogs with predisposing diseases such as immune-mediated disease, sepsis, protein-losing nephropathy, neoplasia, and cardiac disease.

General anesthetic techniques in swine.

General anesthesia techniques for swine can be challenging due to the animal's temperament, anatomic traits, physical condition, and the environment in which the clinician may be working. Taking these factors into consideration, this article provides specific information on preanesthetic considerations, venous catheterization, drug selection, monitoring, perioperative complications and therapy, recovery, and analgesia.

Complications of indwelling, silastic central venous access catheters in dogs and cats.

The records of 35 dogs and two cats with Broviac-Cookea catheters implanted during a one-year period at The Ohio State University Veterinary Teaching Hospital (OSU-VTH) were reviewed for complications. In 36 patients, the catheters were used for daily anesthesia associated with cobalt radiotherapy, and in one dog the catheter was used for parenteral hyperalimentation. The catheters were in place for a mean of 16.7 days. Complications occurred in five patients and included infection or sepsis (n = 3), local abscess formation (n = 1), and local induration (n = 1); all the complications resolved with appropriate therapy. Broviac-Cooke catheters should be considered for use in dogs and cats requiring frequent blood sampling, repeated intravenous access, or in those for which routine venous access is difficult or impossible. The complication rate is minimal (13%) and is similar to that reported in studies of humans with indwelling, silastic catheters.

Comparison of two indwelling central venous access catheters in dogs undergoing fractionated radiotherapy.

Twenty dogs with neoplasms requiring multiple radiation treatments received either percutaneous vascular access catheters (PVACs; Cook, Bloomington, IN) or subcutaneous vascular access ports (SVAPs; Vascular-Access-Ports, Norfolk Medical Products, Inc., Skokie, IL); 10 dogs were entered in each group. All catheters were implanted and removed aseptically and the catheter tips were cultured during implant removal. Complications with PVACs included mild incisional swelling and redness and accidental severance or rupture of the catheter. Complications with SVAPs included incisional or port swelling, bruising or redness, hematoma formation, and pain. Ports in 4 of these dogs could not be used for 1 to 3 days after surgery because of swelling and pain. Surgical wound complications, when pooled for comparison, occurred significantly more frequently with the SVAPs (P = .023). Wound complications associated with both catheters were self-limiting and resolved within 7 days. Bacterial cultures were positive in two PVACs and four SVAP tips, however, none of these dogs had clinical signs of infection or sepsis. Although both types of indwelling catheters were functional in a clinical setting, PVACs were preferred to SVAPs for dogs undergoing radiation therapy because of decreased time for implantation and fewer overall complications.

Resection of subvalvular aortic stenosis. Surgical and perioperative management in seven dogs.

Open heart surgery was performed during cardiopulmonary bypass (CPB) to surgically correct subvalvular aortic stenosis in seven dogs. After initiation of total CPB, cardiac arrest was induced by antegrade and retrograde administration of blood cardioplegia. The subvalvular fibrous stenosis was resected through a transverse aortotomy. Intraoperatively and postoperatively, dobutamine, nitroprusside, lidocaine, blood(-products), and crystalloid solutions were used to manage hypotension and optimize cardiac index. Aortic cross-clamp time varied from 73 to 166 minutes, and duration of CPB varied from 130 to 210 minutes. Iatrogenic incision into the mitral valve in two dogs was the most significant intraoperative complication. Postoperative complications included: hypoproteinemia (n = 7), premature ventricular depolarization (n = 6), increased systemic vascular resistance index (n = 5), increased O2 extraction (n = 3), pulmonary edema (n = 2), and decreased cardiac index (n = 1). All seven dogs were discharged alive and in stable condition. Six dogs are alive and in stable condition after a mean follow up of 15.8 months. This is the first detailed report of CPB in a series of clinical veterinary patients. Using the techniques described in this paper, open heart surgery of considerable duration can be performed successfully in dogs with significant myocardial hypertrophy and endomyocardial fibrosis secondary to subvalvular aortic stenosis.