Comparison of heparinized saline and 0.9% sodium chloride for maintaining peripheral intravenous catheter patency in dogs

Imaging of experimental venous thrombus by means of Doppler and CEUS techniques in dogs

Venous thrombosis has been widely studied in humans, but not in dogs. This study was designed to evaluate a venous thrombus in dogs, from creation to solution, by means of various ultrasonographic techniques. Nine healthy Beagle dogs were included in the study. The venous thrombus was formatted by puncturing the lumen of the external jugular veins and then, the veins were examined with B-mode, color Doppler, pulsed-wave Doppler, and contrast-enhanced ultrasound (CEUS) techniques, at regular intervals, within 210-270 min after venipuncture. Haemodynamic parameters were calculated at two different locations, before and after the site of the thrombus formation. The existence of a thrombus was confirmed by CEUS technique. Thrombus volume and echogenicity were evaluated. The results showed that the visualization of the venous thrombus by color Doppler modality was not feasible in some veins. The blood volume was the parameter that could more precisely indicate the presence or absence of a thrombus. In cases where thrombus volume was less than 0.001 cm3, it was impossible to detect its presence using haemodynamic parameters. The CEUS imaging depicted accurately the size and shape of an anechoic venous thrombus, even when its volume was 0.001cm3.

2022 Update of the Consensus on the Rational Use of Antithrombotics and Thrombolytics in Veterinary Critical Care (CURATIVE) Domain 1- Defining populations at risk

OBJECTIVES

To expand the number of conditions and interventions explored for their associations with thrombosis in the veterinary literature and to provide the basis for prescribing recommendations.

DESIGN

A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. The revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated in this iteration included heartworm disease (dogs and cats), immune-mediated hemolytic anemia (cats), protein-losing nephropathy (cats), protein-losing enteropathy (dogs and cats), sepsis (cats), hyperadrenocorticism (cats), liver disease (dogs), congenital portosystemic shunts (dogs and cats) and the following interventions: IV catheters (dogs and cats), arterial catheters (dogs and cats), vascular access ports (dogs and cats), extracorporeal circuits (dogs and cats) and transvenous pacemakers (dogs and cats).

RESULTS

Of the diseases evaluated in this iteration, a high risk for thrombosis was defined as heartworm disease or protein-losing enteropathy. Low risk for thrombosis was defined as dogs with liver disease, cats with immune-mediated hemolytic anemia, protein-losing nephropathy, sepsis, or hyperadrenocorticism.

CONCLUSIONS

Associations with thrombosis are outlined for various conditions and interventions and provide the basis for management recommendations. Numerous knowledge gaps were identified that represent opportunities for future studies.

Influence of long-stay jugular catheters on hemostatic variables in healthy dogs

OBJECTIVE

To compare hemostatic variables performed on blood samples obtained from indwelling jugular catheters or direct venipuncture over a 72-hour period.

DESIGN

Prospective experimental study.

SETTING

University research laboratory.

ANIMALS

Five healthy neutered male purpose-bred Beagle dogs.

INTERVENTIONS

Each dog was sedated to facilitate placement of a long-stay 20-Ga polyurethane IV catheter into the jugular vein. Blood samples were obtained from the preplaced catheters at 4 time points corresponding to 0, 24, 48, and 72 hours relative to placement. Blood samples were also obtained by direct venipuncture of a peripheral vein using a 21-Ga butterfly catheter and evacuated blood tubes at the same time points. Platelet count, platelet closure time, prothrombin time, activated partial thromboplastin time, fibrinogen, and kaolin-activated thromboelastography were performed on these paired samples at each time point. The patency of the indwelling catheters was maintained by flushing every 6 hours with heparinized saline.

MEASUREMENTS AND MAIN RESULTS

No significant differences were identified in any of the hemostatic variables obtained by either blood collection technique at any time point during the study (P > 0.05). There was also no significant day-to-day variation in any catheter-derived hemostatic variable obtained from individual dogs identified over the course of the study.

CONCLUSIONS

These data suggest that accurate hemostatic variables may be obtained using blood collected from indwelling jugular catheters, maintained with heparinized saline for at least 72 hours, in healthy dogs.

Vascular ultrasonographic findings in canine patients with clinically diagnosed phlebitis

Peripheral vein phlebitis (inflammation) is a relatively frequent complication in dogs, however, published information on the ultrasonographic characteristics is currently lacking. This prospective, observational study describes the ultrasound (US) characteristics of normal canine cephalic veins, and veins with clinical phlebitis. Correlations among US findings and between US findings versus time that the intravenous catheter was in place were investigated. Safety of the US procedure was evaluated. Fifty patients were prospectively recruited for the study and 18 met the final inclusion criteria. Each patient underwent daily US examinations and was assessed for multiple criteria (vascular wall appearance, compressibility, spontaneity of flow, color fill, and presence/absence of filling defects, flow contour, direction, non‐pulsatility). Characteristics of normal canine cephalic veins were as follows: smooth and thin wall, complete compressibility, no flow disturbances, no filling defects, smooth flow contours, and unidirectional, non‐pulsatile flow with no turbulence. Characteristics of cephalic veins with clinical phlebitis were as follows: wall thickening (83%), decreased compressibility (55%), filling defects consistent with intraluminal thrombus (55%), vessel wall hyperechogenicity (44%), and abnormal color Doppler flow (39%). Significant correlations were found between Doppler filling defects and compressibility, Doppler filling defects and presumed thrombosis, and compressibility and presumed thrombosis (P = .001, P = .001, P = .000, respectively). No correlation was found between the US findings and time the intravenous catheter was in place. Findings indicated that duplex and compressibility US are feasible and safe methods for characterizing and monitoring cephalic veins in dogs with clinical phlebitis.

Comparison of heparinized saline and 0.9% sodium chloride for maintaining central venous catheter patency in healthy dogs

BACKGROUND

The purpose of this study was to determine whether heparinized saline (HS) would be more effective in maintaining the patency of central venous catheters (CVCs) in dogs compared to 0.9% sodium chloride. This was a prospective randomized blinded study conducted at a University Veterinary Teaching Hospital.

METHODS

A total of 24 healthy purpose-bred dogs were randomized into two groups: a treatment and a control group. A CVC was placed in the jugular vein of each dog. Each dog in the treatment group had their CVC flushed with 10 IU/mL HS, while dogs in the control group had their CVC flushed with 0.9% sodium chloride every 6 h for 72 h. Immediately prior to flushing, each catheter was evaluated for patency by aspiration of blood. The catheter site was also evaluated for phlebitis, and a rectal temperature was obtained in each dog every 6 h. Prothrombin (PT) and activated partial thromboplastin (aPTT) times were evaluated prior to the administration of any flush solution. Results were then compared to values obtained 72 h later.

RESULTS

All CVCs in both groups were patent after 72 h, which was demonstrated by aspiration of blood and ease of flushing the catheter. Two CVCs in the 0.9% sodium chloride group had a negative aspiration at hour 12 and 36, respectively. One CVC in the HS group had a negative aspiration at hour 18. Signs of phlebitis occurred in three dog: two in the 0.9% sodium chloride group and one in the HS group. No dog was hyperthermic (>103 °F). Two catheters were inadvertently removed by dogs in the HS group during the study. There were no significant differences in catheter patency, incidence of phlebitis, or incidence of negative aspirations between both groups. aPTT and PT values remained within the normal reference range for all dogs in both groups. Ultimately, 0.9% sodium chloride was as effective as 10 IU/mL HS in maintaining the patency of CVCs for up to 72 h in healthy dogs. Further evaluation in clinical patients is warranted.