Short-duration peripherally inserted central catheters do not alter viscoelastic parameters in healthy dogs.

Objective: To determine if short-duration peripherally inserted central catheters (PICCs) cause a hypercoagulable state in healthy dogs, based on point-of-care viscoelastic coagulation monitor (VCM). Animals: Ten beagle dogs were randomly and equally allocated into control and PICC groups. Procedure: Control dogs had VCM analysis on whole blood following direct venipuncture before sedation (T0) and 2 h after sedation (T2). In the experimental group, a PICC was placed (medial saphenous or femoral vein) under sedation and removed after 4 h, with measurements before placement (T0) and 2 and 6 h after placement (T2 and T6, respectively). Parametric data were analyzed using 1-way ANOVA with Holm-Sídák test for multiple comparisons and paired or unpaired Student's t-test. Nonparametric data were analyzed using Friedman test with Dunn multiple comparison test for Wilcoxon matched-pairs signed-rank test, and Mann-Whitney U test for PICC group, control group, and to compare PICC versus control groups, respectively. Results: Clot formation time was longer at T2 versus T6 (P = 0.0342, but not clinically relevant) in the PICC group, with no significant differences between the PICC and control groups. Conclusion and clinical relevance: Short-term placement of a PICC line did not alter viscoelastic endpoints in healthy beagles.

L'utilisation de courte durée d'un cathéter central inséré par voie périphérique n'affecte pas les paramètres viscoélastiques chez les chiens sains. Objectif: Déterminer si les cathéters centraux insérés par voie périphérique (CCIP) pour une courte durée provoque un état d'hypercoagulabilité chez des chiens en bonne santé sur la base des mesures du Viscoelastic Coagulation Monitor (VCM) au point de soins. Animaux: Dix chiens sains de race beagle ont été choisis et répartis de façon égale et aléatoire dans un groupe témoin et un groupe de CCIP. Procédure: Les chiens témoins ont eu une prise de sang et analyse par VCM avant sédation (T0) et 2 heures après la sédation (T2). Dans le groupe expérimental, un CCIP a été mis en place (veines saphènes ou fémorales médiales) sous sédation et retiré après 4 heures. Les mesures viscoélastiques sur le sang frais ont été effectuées avant la pose du CCIP (T0), 2 heures après la pose (T2) et 2 heures après le retrait/6 heures après la pose du cathéter (T6). L'analyse statistique des données paramétriques a été faite par le test ANOVA à un facteur avec un test de comparaisons multiples de Holm-Sídák pour le groupe CCIP, un test t de Student apparié pour le groupe témoin, et un test t de Student non apparié pour comparer les groupes CCIP et témoin. Les données non paramétriques ont été analysées à l'aide du test de Friedman avec un test de comparaison multiple de Dunn pour le groupe CCIP, du test de rang signé de Wilcoxon pour le groupe témoin et du test de Mann-Whitney U pour comparer les groupes CCIP et témoin. Résultats: Pour le groupe CCIP, le temps de formation du caillot à T2 était plus long mais non cliniquement pertinent. comparativement à T6 (P = 0,0342) et il n'y avait aucune différence significative entre les groupes CCIP et témoin. Conclusion et pertinence clinique: La pose d'un CCIP pour une courte durée n'a pas modifié les variables viscoélastiques chez les chiens beagle en bonne santé.(Traduit par les auteurs).

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.

Ultrasound-guided vessel catheterization in adult Yorkshire cross-bred pigs.

OBJECTIVE: To describe an ultrasound-guided approach for venous and arterial vascular access and catheterization in anesthetized adult Yorkshire cross-bred pigs. STUDY DESIGN: Prospective experimental study. ANIMALS: Ten adult female Yorkshire cross-bred pigs, weighing 78.4 ± 5.6 kg (mean ± standard deviation). METHODS: Using ultrasound guidance and the Seldinger technique, a 7 Fr, 20 cm triple-lumen central venous catheter was placed in the external jugular vein and an 18 gauge, 16 cm catheter was placed in the femoral artery. The success rate of catheterization and the incidence of catheter patency over 24 hours of general anesthesia were recorded. RESULTS: Catheterization of the external jugular vein was successful in 10 out of 10 pigs and catheterization of the femoral artery was successful in eight out of 10 pigs. A surgical dissection technique on the femoral artery was performed in two pigs. Venous and arterial catheter patency was maintained in all pigs over the 24 hour study period. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound guidance resulted in success rates of 100% for catheterization of the external jugular vein and 80% for catheterization of the femoral artery in anesthetized adult Yorkshire cross-bred pigs. This technique is a noninvasive, easily performed alternative to surgical exposure of the vessels in large pigs undergoing surgical instrumentation for biomedical device testing.

JUGULAR CENTRAL VENOUS CATHETER PLACEMENT THROUGH A MODIFIED SELDINGER TECHNIQUE FOR LONG-TERM VENOUS ACCESS IN CHELONIANS.

Long-term or repeated venous access in chelonians is difficult to obtain and manage, but can be critically important for administration of medications and blood sampling in hospitalized patients. Jugular catheterization provides the most rapid and secure route for vascular access, but catheters can be difficult to place, and maintaining catheter patency may be challenging. Long multilumen polyurethane catheters provide flexibility and sampling access, and minimize difficulties, such as catheter displacement, that have been encountered with traditional over-the-needle catheters. We describe placement of 4 Fr. 13-cm polyurethane catheters in three chelonians with the use of a modified Seldinger technique. Venous access was obtained with the use of an over-the-needle catheter, which allowed placement of a 0.018-in.-diameter wire, over which the polyurethane catheter was placed. Indwelling time has ranged between 1 and 4 mo currently. All tortoises were sedated for this procedure. Polyurethane central catheters provide safe, long-term venous access that allows clinicians to perform serial blood sampling as well as intravenous administration of medications, anesthetic agents, and fluids. A jugular catheter can also allow central venous pressure measurement. Utilization of central line catheters was associated with improvements in diagnostic efficiency and therapeutic case management, with minimal risks and complications.

Microorganism colonization of peripheral venous catheters in a small animal clinical setting.

OBJECTIVE: To compare the incidence of microorganism colonization of peripheral venous catheters (PVCs) placed in the Emergency Department (ED) to those placed in a routine preoperative setting. The relationship between catheter tip colonization and patient urgency (as assessed by triage priority) was also evaluated. DESIGN: Prospective, observational study from January 2021 to October 2021. SETTING: Emergency room and clinical areas of a large, urban, tertiary referral center. ANIMALS: Three hundred dogs and 94 cats with a PVC in place for a minimum of 24 hours were enrolled in the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two hundred and eighty-eight PVCs were placed in the ED and 106 were placed preoperatively. The overall colonization rate was 10.4% (41/394). Sixteen bacterial and 1 fungal genera were cultured. Eight of these bacterial genera (25/51 [49%] bacterial isolates) were resistant to at least 1 antimicrobial class. Twenty-nine of 288 (10.1%) catheters positive for colonization were placed in the ED, whereas 12 of 106 (11.3%) were placed preoperatively. There was no association between microorganism growth on catheters and clinical area of catheter placement. There was also no association between ED patient urgency and positive catheter tip culture. No significant risk factors were identified predisposing to colonization of PVCs. CONCLUSIONS: The overall incidence of microorganism colonization of PVCs in this study population was equivalent to, or lower than, previously reported in veterinary literature. There was no statistical difference between the catheters placed in the ED and those placed for routine surgical procedures. Patient urgency did not affect the incidence of positivity of peripheral catheter tip cultures.

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.

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.

[Venous catheters in horses - early ultrasonographic venous abnormalities and evidence of biofilms]. / Ultrasonografische Früherkennung von Venenveränderungen sowie der Nachweis von Biofilmen auf Venenverweilkathetern beim Pferd.

OBJECTIVE: Complications associated with indwelling intravenous catheters vary from minor to severe. Changes in tissue architecture and vein structure may be detectable prior to clinical alterations. The aim of the study was to characterize and compare changes in a catheterized vein and surrounding tissue by clinical and ultrasonographic examination. Microbiological infestation of catheter specimens was assessed. MATERIAL AND METHODS: In this prospective, observational, clinical study 55 horses with an indwelling intravenous catheter have been included. Subsequent to catheter placement, vein and surrounding tissue were daily examined clinically and by ultrasonographic examination at predetermined localizations. After sterile removal of the catheters, specimens underwent microbiological testing and scanning electron microscopy. Obtained data were analyzed via descriptive statistics. Thickness of the venous wall was compared at predetermined localizations and time points for several parameters with the help of non-parametric tests (level of significance at p < 0.05, post-hoc Bonferroni correction). RESULTS: Overall, in 41.8 % of the horses transient alterations (swelling) of the surrounding tissue occurred during catheterization. Median catheterization was 69.5 hours (19 hour-10 days). With ultrasonography, venous valves and collateral vessels could be detected reliably. Significant alterations in wall thickness during catheterization were associated with various factors (location site [p ≤ 0.001], season [p = 0.006], anesthesia [p ≤ 0.001]).Microbiological analysis revealed a positive result in 23.5 %, 12 of the 51 samples; raster electron microscopy showed presence of bacteria in 25.0 %, 4 of the 16 investigated catheter samples. CONCLUSION AND CLINICAL RELEVANCE: Local tissue changes at the insertion site of the catheter are commonly associated with catheterization, and are easily detectable with ultrasonography. Despite the easy performance in a clinical setting, the benefit of routine ultrasonographic monitoring of catheterized veins might be questionable with regard to early identification and prediction of catheter-associated venous disease. Bacteria might be detectable morphologically on the catheter but frequently lack a positive result from standard bacterial cultivation.

Comparison of success rate and time to obtain venous cannulation by cutdown technique at 3 locations using canine cadavers.

OBJECTIVE: To compare the success rates and time taken to cannulate the jugular, cephalic, and lateral saphenous veins using a cutdown technique by personnel with 4 different levels of experience. DESIGN: Prospective ex vivo study. SETTING: Veterinary university teaching hospital. ANIMALS: Eighteen canine cadavers. INTERVENTIONS: Recently euthanized canine patients that were donated to the hospital for research purposes between October 2019 and March 2020 were enrolled. Four groups of personnel participated in the study to give 4 varying levels of experience: 8 final year veterinary students, 2 registered veterinary nurses, 1 emergency and critical care intern and 1 ACVECC diplomate. Each cannula placer had 5 minutes to attempt cannulation by venous cutdown at each site. Time to venous cannulation (VC) was compared for each site and group and complications encountered during each attempt recorded. MEASUREMENTS AND MAIN RESULTS: The overall success rate for cannulation of the jugular, cephalic, and lateral saphenous veins were 81%, 84%, and 87%, respectively. The median times for venous cutdown for all personnel were as follows: jugular vein 119 s (range 51-280 s), cephalic vein 82 s (range 39-291 s), and lateral saphenous vein 110 s (range 41-294 s). There was no difference in time to VC between veins. When comparing personnel at the 3 cannulation sites, the ACVECC diplomate was faster than the registered veterinary nurses and students (P = 0.042 and P = 0.048, respectively). No differences were found between any other groups. Complications encountered often related to cadaver factors such as hematoma from antemortem venipuncture. CONCLUSIONS: All groups were able to perform venous cutdown at each site with good overall success even without prior experience of the technique. VC by cutdown technique of the jugular, cephalic, or lateral saphenous veins may be considered in an emergency setting by personnel of various skill levels.

Minimally invasive ultrasound-guided technique for central venous catheterization via the external jugular vein in pigs.

OBJECTIVE: To describe an ultrasound-guided technique for central venous catheter placement via the external jugular vein (EJV) in pigs. ANIMALS: 96 healthy Landrace-Poland China barrows (approx 16 weeks old with a mean weight of 70 kg). PROCEDURES: Pigs were anesthetized. With ultrasound guidance, a needle was inserted into the EJV without a large incision or cutdown procedure. A guidewire was inserted through the needle into the vein. A modified Seldinger technique was used to advance a catheter into the vessel until the tip was in the cranial vena cava near the right atrium. A trocar was used to create a tunnel through the subcutaneous tissues from the catheter insertion site to between the dorsal borders of the scapulae. The free end of the catheter was passed through that tunnel. An extension was attached to the catheter and secured to the skin. Pigs were euthanized and underwent necropsy at completion of the study for which they were catheterized. RESULTS: Central venous catheters were successfully placed in all 96 pigs and facilitated collection of serial blood samples with minimal stress. Catheters remained in place for a mean of 6 days (range, 4 to 10 days). Necropsy revealed abscesses along the subcutaneous catheter tract in 9 pigs. Twenty pigs had histologic evidence of phlebitis and fibroplasia in the cranial vena cava. CONCLUSIONS AND CLINICAL RELEVANCE: The described technique, in combination with extensive socialization, allowed serial collection of blood samples with minimal stress and restraint and is an alternative to surgical cutdown procedures for catheter placement.

Electrocardiography-guided and retrospective analysis of central venous catheter placement in the dog.

OBJECTIVE: To compare the success rates of central venous catheter placement (CVCP) in dogs using electrocardiograph (ECG)-guided and external landmark ('blind') techniques. To report success rates determined retrospectively of CVCPs in dogs using external landmarks at a tertiary referral institution. STUDY DESIGN: Prospective blinded comparison of techniques. Retrospective analysis of case records. ANIMALS: Adult Beagles weighing 11.9 +/- 2.6 kg were used in the experimental group (n = 38). Various breeds of dogs were in the retrospective clinical group (n = 33). METHODS: Laboratory dogs were anesthetized and CVCPs were placed using a modified Seldinger technique. Catheter tip position was first based on external landmarks and then the catheter was repositioned using an ECG-guided placement. The ECG-guided technique used the V-lead with the positive electrode attached to the guide wire. Catheter placement was determined by moving the catheter cephalad and caudad to the point of maximum p-wave amplitude and then withdrawing the catheter 1-2 cm from this point. Catheter position with each technique was determined using a lateral thoracic radiograph. Retrospective data were collected from the medical records of dogs that had CVCPs using anatomical landmarks and corresponding thoracic radiographs. RESULTS: The number of successful CVCP attempts was the same for both prospective groups (21/38). There was no statistically significant difference in success between the ECG-guided technique and the blind technique. From the retrospective investigation 10/33 of the cases that fit the criteria had correct CVCPs. CONCLUSIONS AND CLINICAL RELEVANCE: The odds of correctly placing a central venous catheter by ECG-guidance were the same as the external landmark technique. The ECG-guided technique may be useful in situations where external landmarks are not readily available.

Sedative and cardiorespiratory effects of dexmedetomidine and buprenorphine administered to cats via oral transmucosal or intramuscular routes.

OBJECTIVE: To determine if buprenorphine plus dexmedetomidine administered via the oral transmucosal route produces sufficient sedation in cats so that students can insert intravenous catheters. STUDY DESIGN: Prospective, randomized, blinded, clinical trial. ANIMALS: Eighty-seven shelter-owned female cats aged 4-48 months, weighing 1.1-4.9 kg. METHODS: Cats were randomly allocated to two treatment groups based on route of drug administration: oral transmucosal (OTM), or intramuscular (IM). Buprenorphine (20 microg kg(-1)) plus dexmedetomidine (20 microg kg(-1)) were administered as pre-medicants via one of these two routes. Prior to and 20 minutes after drug administration, heart and respiratory rates, systolic arterial pressure, and posture were measured and recorded. Twenty minutes after drug administration the same variables plus each cat's response to clipper sound, clipping, and restraint were recorded; higher scores indicated more sedation. RESULTS: There were no significant differences between the two groups prior to pre-medication. Within each treatment group heart rate was significantly lower 20 minutes after treatment, but it did not differ significantly between the two groups. Twenty minutes after treatment, respiratory rate was significantly less in the OTM group, but did not differ significantly between the two groups. Systolic arterial pressure did not differ within or between the two groups at either time. Scores for posture increased significantly within both groups, and cats in the IM group had higher scores after treatment. Twenty minutes after treatment, cats in the IM group had higher scores for clipping and restraint than OTM cats. Ketamine (IM) was necessary to facilitate catheterization in 25% and 16% of cats in the OTM and IM groups, respectively, but this was not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of dexmedetomidine plus buprenorphine by the OTM route is easy to perform, but produces less sedation than the IM route for IV catheterization in cats.

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.

Sonographically guided placement of intravenous catheters in minipigs.

Many procedures in minipigs require establishment of reliable deep venous access with a large-bore catheter. In animal experiments, such catheters are typically implanted surgically. In clinical settings, however, ultrasound imaging is routinely used to facilitate safe, minimally invasive puncture of deep vessels. The authors describe a technique for using ultrasound guidance to puncture and cannulate the minipig femoral vein. They carried out the procedure in six minipigs for the purpose of injecting contrast agents for subsequent imaging scans. The procedure was ultimately successful in all pigs, took 10 min on average and resulted in no physiological complications. In one minipig, however, a 10-cm-long catheter became dislodged from the femoral vein; use of a longer (25-cm-long) catheter was optimal for establishing reliable intravenous access.

Evaluation of the placement and maintenance of central venous jugular catheters in critically ill dogs and cats.

OBJECTIVE: To describe problems noted during central venous jugular catheter (CVJC) placement, conditions associated with unsuccessful catheterization, and CVJC maintenance complications. DESIGN: Prospective observational study from September 2014 to September 2015. SETTING: University veterinary teaching hospital. ANIMALS: Twenty-seven dogs and 20 cats hospitalized in a veterinary ICU. Patients were excluded if previously hospitalized with a CVJC or lacked sufficient data. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Ninety-one percent of indwelling CVJCs were placed successfully (43/47, 95% CI: 80%, 98%). Procedural-related difficulties that resulted in the inability to place a CVJC totaled 18/63 (28.6%, 95% CI: 18%, 41%) and included the inability to puncture the vessel (10), hematoma (6), malposition (1), and dislodgement (1). Procedural complications occurred in 24/47 patients (51%, 95% CI: 36%, 66%) and included cardiac dysrhythmias (13), hematoma (6), CVJC placement failure (4), and malposition (1). Risk factors associated with multiple catheterization attempts included increased age (7.5 years [± 4.2] vs 10.6 years [± 4.1], P = 0.04), smaller size (8.0 kg [0.6-51.9 kg] vs 4.4 kg [2.6-6.8 kg], P < 0.01) and thinner body condition score (median 5/9 [2/9-9/9] vs 4/9 [2/9-7/9], P = 0.04). The risk factor associated with dysrhythmias was smaller patient size (6.8 kg [2.6-51.9 kg] vs 4.8 kg [0.6-29.5 kg], P = 0.04). Eighteen indwelling complications occurred in 14 patients and included mechanical obstruction (7), skin irritation (6), malposition (4), and inflammation (1). Risk factors for indwelling complications included longer dwell time (5 days [2-30] vs 3 days [1-10], P < 0.01) and the administration of an irritant medication (P = 0.02). CONCLUSIONS: Complications were documented in the placement and maintenance of CVJCs in critically ill patients with a low incidence of life-threatening sequelae. Risk factors associated with both unsuccessful CVJC placement and indwelling CVJC complications were identified.

Improving the Patency of Jugular Vein Catheters in Sprague-Dawley Rats by Using an Antiseptic Nitrocellulose Coating.

Preclinical studies in animals often require frequent blood sampling over prolonged periods. A preferred method in rats is the implantation of a polyurethane catheter into the jugular vein, with heparinized glycerol as a lock solution. However, analysis of various biologic compounds (for example, microRNA) precludes the use of heparin. We used sodium citrate as an alternative to heparin but observed more frequent loss of catheter patency. We hypothesized that this effect was due to evaporation of lock solution at the exteriorized portion of the catheter, subsequent blood infiltration into the catheter, and ultimately clot formation within the catheter. We therefore tested evaporation and its variables in vitro by using 5 common catheter materials. We used the migration of dye into vertically anchored catheters as a measure of lock displacement due to evaporation. Exposure to dry room-temperature air was sufficient to cause dye migration against gravity, whereas a humid environment and adding glycerol to the lock solution mitigated this effect, thus confirming loss of the lock solution from the catheter by evaporation. We tested 4 catheter treatments for the ability to reduce lock evaporation. Results were validated in vivo by using male Sprague-Dawley rats (n = 12) implanted with polyurethane jugular vein catheters and randomized to receive a nitrocellulose-based coating on the exteriorized portion of the catheter. Coating the catheters significantly improved patency, as indicated by a Kaplan-Meier log-rank hazard ratio greater than 5 in untreated catheters. We here demonstrate that a simple nitrocellulose coating reduces evaporation from and thus prolongs the patency of polyurethane catheters in rats.

Hemodialysis catheter-associated fibrin sheath in a dog.

OBJECTIVE: To describe an intravascular fibrin sheath associated with a hemodialysis catheter in a dog. CASE SUMMARY: A 4-year-old dog presented for hemodialysis to treat acute kidney injury. Hemodialysis catheter dysfunction during the course of treatment was temporarily alleviated using a tissue plasminogen activator. A thrombus composed of fibrin and granulation tissue creating a sheath around the catheter and focally adherent to the vessel wall was identified on postmortem evaluation. NEW OR UNIQUE INFORMATION PROVIDED: Fibrin sheath formation is a commonly recognized problem of central venous catheters used for hemodialysis in people and is likely a common problem in veterinary patients undergoing dialysis as well. This report provides a description of the clinical features of the catheter dysfunction, response to treatment, postmortem radiographic and direct imaging, and histology of the fibrin sheath, and also provides a brief review of potential management techniques that have been described in people.

One-step method for catheterising the jugular vein of cats to enable repeated blood sampling.

A one-step method for catheterising the jugular vein of cats for taking multiple blood samples was developed, with the aid of radiography, to determine an appropriate internal catheter length for adult cats. The effects of multiple blood sampling and heparin flushes on the cats' haematocrit and blood total solids were also assessed. Seven healthy adult cats were used. A total of 128 of 132 (97 per cent) blood samples were collected successfully through a 19 G, 30.5 cm catheter introduced as a central venous catheter and maintained in place during two periods of 48 hours. The haematocrit and total solids were significantly decreased in all the cats, but no clinically significant blood loss or coagulation disorders were observed.

Comparison of time to obtain intraosseous versus jugular venous catheterization on canine cadavers.

OBJECTIVE: To compare the time required and the success rate of personnel with 4 different levels of experience to place a humeral intraosseous (IO) catheter versus a jugular venous catheter (IV) in cadaver dogs. DESIGN: Prospective study. SETTING: Veterinary university teaching hospital. INTERVENTIONS: Canine cadavers from recently euthanized dogs were obtained from the cadaver donation program between May and December 2014. Catheter placers (CPs) with varying clinical experience, including a first year emergency and critical care resident, a senior emergency veterinary technician (VTS certified), a final year veterinary student, and an ACVECC diplomate, participated in the study. Each CP catheterized a total of 6 dogs so that there was a total of 6 IO and 6 IV catheters placed, by automatic rotary insertion device (with an EZ-IO gun) and vascular cut-down technique, respectively, for each CP. Time for IO catheterization and IV catheterization was recorded and compared. The success of IO catheterization and IV catheterization was verified by visualization of an injection of iodinated contrast material under fluoroscopy within the medullary cavity or vessel. ANIMALS: Twenty-four canine cadavers. MEASUREMENTS AND MAIN RESULTS: Outcomes were analyzed using the Wilcoxon rank-sum test and the Kruskal-Wallis one-way analysis of variance. The median time for all IO catheterization operators was faster at 55.4 seconds (range 15.0-153.0 s) compared to the median time for all IV catherization operators at 217.3 seconds (range 55.6-614 s). The success rate for IO and IV was equal at 87.5%. CONCLUSION: IO catheterization using an automatic rotary insertion device was performed more rapidly and successfully than jugular venous catheterization using a cut-down technique in canine cadaver. These findings suggest IO catheterization may be more efficient for gaining vascular access in the appropriate emergency clinical situations when preexisting IV access does not exist.