Central venous access to the cranial vena cava via the omobrachial vein in the dog

Background– The omobrachial vein is a superficial vein that crosses the brachial region of the dog. It terminates in the cranial vena cava, offering a novel site for central venous catheterization into the cranial thorax. Case Summary– The omobrachial vein served as a point of access to the cranial vena cava for treatment and monitoring of a critical canine patient in this report. The omobrachial vein was catheterized using the modified‐Seldinger technique due to contamination of or lack of availability of commonly used central venous catheter insertion sites. Conclusion– Access to the cranial vena cava via the omobrachial vein was easily achieved, and the catheter was maintained without complication for 10 days. Although the site was successfully used in the patient in this report, omobrachial vein anatomy is not consistent in all dogs.     

Evaluation of regional limb perfusion with amikacin using the saphenous,cephalic, and palmar digital veins in standing horses

Previous studies have shown that regional limb perfusion (RLP) using the palmar digital (PD) vein delivers therapeutic concentration of amikacin to the distal limb. Our hypothesis was that using the cephalic and saphenous veins for RLP will enable delivery of therapeutic concentrations of amikacin to the distal limb. Nineteen healthy horses participated in the study. The cephalic, saphenous, or PD vein was used to perfuse the limb with amikacin. Two grams of amikacin was used for RLP using the saphenous and the cephalic veins, and one gram was used in the PD vein. Synovial samples were collected from the metacarpo‐/metatarsophalangeal (MCP/MTP) joint, and blood samples were collected from the jugular vein. Maximum concentration (Cmax) of amikacin in the MCP/MTP joint using the cephalic and the saphenous vein was 277 and 363 mg/L, respectively. The amikacin concentrations achieved in the synovial fluid of the MCP/MTP joint in the current study were between 69 and 91 times the minimally inhibitory concentration of common susceptible bacterial pathogens causing orthopedic infections in horses. To conclude, this study shows that use of the proximal veins for RLP to treat distal limb infections is a viable alternative to using the palmar or plantar digital vein.     

Evaluation of a hand-held lactate analyzer in dogs

A hand-held lactate test device and a blood gas auto analyzer were compared. The objective of the study was to evaluate the performance of the hand-held device in dogs in a clinical setting. Blood lactate levels were evaluated on 30 samples from healthy client-owned dogs and 48 samples from client-owned dogs with various diseases. A blood sample was collected from each healthy dog by either jugular or cephalic venipuncture and from each sick dog from the jugular, cephalic, or saphenous vein, or from an arterial catheter if applicable. One and a half milliliters of the blood sample was immediately transferred to a heparinized vacutainer tube. Enough blood was then drawn from the heparinized tube to allow split sample simultaneous analysis with both machines. Samples from the sick dogs represented a wide range of clinically relevant lactate values. Good agreement between lactate values from both devices was obtained in both sick and healthy dogs. Lactate values in the healthy group (< 2.9 mmol/L with the hand-held device, < 2.6 mmol/L with the blood gas analyzer) were similar to those previously reported (< 2.5 mmol/L). The results of this study support the use of the hand-held device in dogs in a clinical setting.     

A Comparison of Simultaneously Collected Arterial, Mixed Venous, Jugular Venous and Cephalic Venous Blood Samples in the Assessment of Blood-Gas and Acid-Base Status in the Dog

Blood samples were collected simultaneously from the pulmonary artery, jugular vein, cephalic vein, and carotid artery in awake dogs. Blood-gas and acid-base values were measured from these blood samples in normal dogs and in dogs after production of metabolic acidosis and metabolic alkalosis. The values obtained from each of the venous sites were compared with those obtained from arterial blood to determine if venous blood from various sites accurately reflected acid-base balance and could therefore be used in the clinical patient. The results of this study demonstrated significant differences between the blood from various venous sites and the arterial site for PCO2 and pH in all acid-base states. Significant differences for standard bicarbonate (SHCO3) were found only when jugular and cephalic venous blood were compared with arterial blood in dogs with a metabolic acidosis. No significant differences were found for BE when blood from the venous sites was compared with arterial blood. The values for pH, HCO3, TCO2, BE, and SHCO3 measured on blood collected at the various venous sites were found to correlate well with those obtained from arterial blood, with a correlation coefficient of 0.99 for HCO3, TCO2, BE, and SHCO3. These correlation coefficients, together with similar values in BE at all collection sites, indicate that, in the dog with normal circulatory status, blood from any venous site will accurately reflect the acid-base status of the patient.     

Effect of sampling site, repeated sampling, pH, and PCO2 on plasma lactate concentration in healthy dogs

OBJECTIVE: To characterize the variation in plasma lactate concentration among samples from commonly used blood sampling sites in conscious, healthy dogs. ANIMALS: 60 healthy dogs. PROCEDURE: Cross-sectional study using a replicated Latin square design. Each dog was assigned to 1 of 6 groups (n = 10) representing all possible orders for 3 sites (cephalic vein, jugular vein, and femoral artery) used to obtain blood. Samples were analyzed immediately, by use of direct amperometry for pH, PO2, Pco2, glucose, and lactate concentration. RESULTS: Significant differences in plasma lactate concentrations were detected among blood samples from the cephalic vein (highest), femoral artery, and jugular vein (lowest). Mean plasma lactate concentration in the first sample obtained, irrespective of sampling site, was lower than in subsequent samples. Covariation was identified among plasma lactate concentration, pH, and PCO2, but correlation coefficients were low. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma lactate concentrations differed among blood samples from various sites. A reference range for plasma lactate concentration was 0.3 to 2.5 mmol/L. Differences in plasma lactate concentrations among samples from various sites and with repeated sampling, in healthy dogs, are small. Use of the reference range may facilitate the clinical use of plasma lactate concentration in dogs.     

Comparison of a central and a peripheral (cephalic vein) injection site for the measurement of cardiac output using the lithium-dilution cardiac output technique in anesthetized dogs

The objective of this study was to determine the agreement between cardiac output measured by central (cranial vena cava) versus peripheral (cephalic vein) venous injection of lithium chloride for lithium-dilution cardiac output (LiDCO) determination in the dog. Five dogs (2 males, 3 females), anesthetized with halothane, were used. With each dog, 12 alternating central and peripheral LiDCO measurements were made, resulting in 10 paired comparisons. A total of 50 comparisons were obtained, the cardiac output measurements ranging from 1.11 to 2.76 L/min. The LiDCO measurement from the cephalic vein was similar to that obtained from the recommended central venous site: the difference between the central and cephalic vein determinations for all measurements was 0.098 ± 0.336 L/min (mean ± 2 standard deviations). Linear regression analysis demonstrated a slope of 1.050 (95% confidence interval 0.904 to 1.196) and a y intercept of 0.005 (r = 0.902). Therefore, although the central venous site is recommended by the manufacturer, the cephalic vein can be used instead in the dog, eliminating the need for central venous catheterization and thus reducing time and expense.     

Arteriovenous Fistulas as an Aid in Blood Collection from Canine Blood Donors

To facilitate blood collection from blood donor dogs, arteriovenous fistulas were established between the common carotid arteries and external jugular veins in five adult dogs. Twelve to 16 mm, side-to-side anastomoses were created using simple interrupted 6–0 polypropylene sutures. Starting 1 month after the surgical procedure, 500 ml of blood was collected from each dog as required. Electrocardiography, thoracic radiography, and cardiac output and rate were used to monitor cardiac changes. Blood flow characteristics, and proliferative and dystrophic cellular changes occurring in the vessels were documented in one dog.
The mean blood collection times were 2 minutes and 45 seconds from the fistula site and 9.0 minutes from the opposite jugular vein. Ventricular hypertrophy and myocardial changes were observed on electrocardiogram in two dogs, and radiographic evidence of pulmonary hypertension was noted in three dogs. Reversed blood flow was documented in the common carotid artery and external jugular vein distal to the arteriovenous fistula. Four dogs were still in use as blood donors 1 to 1 1/2 years after establishment of the fistulas. Clinical signs of congestive heart failure were not observed.     

Comparison of haematological analyses of blood taken from the cephalic and marginal ear veins in cats

Various haematological components were compared in blood samples from the cephalic and marginal ear vein of 21 cats. Test results tended to be higher in blood samples from the cephalic vein, although significant differences were only detected for haemoglobin concentration, white blood cell count and the absolute numbers of neutrophilic granulocytes and lymphocytes. Differences in test results between the two veins were small and apparently of only minor practical importance, thereby further substantiating the suitability of the marginal ear vein nick technique as a means of obtaining small blood samples from cats.     

Ultrasonographic evaluation of partially attenuated congenital extrahepatic portosystemic shunts in 14 dogs

Doppler ultrasonography was used to evaluate the portal vein in 14 dogs before, immediately after and four weeks after a partial ligation of a congenital extrahepatic portocaval shunt. By four weeks after the operation, the hepatofugal or zero flow in the portal vein segment cranial to the shunt origin had become a hepatopetal flow in 13 of the dogs, which became clinically healthy. The other dog continued to have a hepatofugal flow in the portal vein cranial to the origin of the shunt and continued to show clinical signs of hepatic encephalopathy. The shunt remained functional in six of the dogs, and three of them developed portosystemic collaterals in addition. In the other eight dogs the patent shunt was non-functional, because a hepatopetal flow was detected in the shunt adjacent to the portal vein. This flow was the result of the splenic vein entering the shunt, and the splenic blood dividing; some flowed via the shunt towards the portal vein, preventing the portal blood from shunting, and the rest flowed via the attenuated shunt segment to the caudal vena cava. Shunting of the splenic venous blood was clinically insignificant.     

ULTRASONOGRAPHIC DIAGNOSIS OF PORTAL VEIN THROMBOSIS IN FOUR DOGS

Ante mortem diagnosis of portal vein thrombosis was determined ultrasonographically in four dogs. In each dog the thrombus was visible in two-dimensional, grey-scale images of the portal vein obtained through a right intercostal window. Duplex-Doppler measurements and color-Doppler images provided information about the effects of thrombosis on portal blood flow. Reduced portal blood flow compatible with portal hypertension was detected in three dogs. A hypercoagulable state was probably involved in the pathogenesis of portal vein thrombosis in two dogs, one with pancreatitis and gastrointestinal blood loss and another with protein-losing nephropathy and probable immune-mediated anemia. The third dog had chronic ehrlichiosis; thrombosis was probably secondary to vasculitis. The remaining dog had thrombosis secondary to invasion of the portal vein by a recurrent duodenal neoplasm. This dog was euthanized because the tumor was considered inoperable. The dog with pancreatitis developed acute portal hypertension due to obstruction of the portal vein by the thrombus and was euthanized. The dogs with protein-losing nephropathy and ehrlichiosis were treated medically and recovered. Although portal vein thrombosis is uncommon, this complication should be considered in dogs with a variety of abdominal or systemic disorders. Ultrasonography is a practical method for diagnosis of portal vein thrombosis and detection of the underlying cause.     

The influence of boar pheromones on the contractile reactivity of the isolated superficial veins of the nose and face in ovariectomized prepubertal gilts and in gilts during sexual maturation

This study was designed to establish: a) whether boar pheromones, 5alpha-androstenone and 5alpha-androstenol, may affect the contractile reactivity of superficial veins of the face in prepubertal gilts deprived of ovarian hormones, and b) what is the influence of ovarian hormones secreted during sexual maturation on the contractility of these veins. The isolated rings of frontal, facial and dorsal nasal veins were treated with androstenone (5alpha-androst-16-en-3-one), androstenol (5alpha-androst-16-en-3-ol) and testosterone (17beta-hydroxy-4-androsten-3-one) in concentrations of either 1 or 10 microM. Changes in the contractile activity of the isolated vein segments were measured using isometric transducer and recorded on HSE-ACAD W software. Sex boar pheromones androstenol and androstenone affected the contractility of the superficial veins of the face and nose in both of the prepubertal ovariectomized gilts and prepubertal intact animals. The way these veins reacted to pheromones differed between animal groups, particular vessels and even their parts and was also dose - dependent. In prepubertal ovariectomized gilts, androstenol had stronger action and caused the constriction of the facial vein, dorsal nasal vein and the distal part of the frontal vein. Androstenone produced constriction of the nasal vein, distal part of the frontal vein and proximal part of facial vein, but relaxation of the proximal part of the frontal vein and the distal part of the facial vein. In prepubertal untreated gilts, androstenone was more effective and strongly influence on the constricted of the frontal vein and facial vein and produced the relaxation of the nasal vein. Androstenol influence on the constriction the frontal vein and the distal parts of the facial vein and nasal vein, and influence o the relaxtion their proximal parts. Testosterone used as a control androgen affected both superficial veins of the face veins in a dose-dependent manner, and, at a higher dose, increased the contractility more effectively. Only the nasal vein did not react to this hormone. The present results suggest the existence in prepubertal gilts of frontal and facial veins' specific reactivity which may participate in the regulation of blood flow from the nasal cavity to the perihypophyseal vascular complex and play a role in the humoral pathway for the male pheromone priming functions in the central nervous system. This reactivity was displayed by the vessels in prepubertal gilts without ovarian hormones. The presence of active ovaries in maturing gilts changed the reactivity of these veins to pheromones and testosterone.     

A model to investigate hepatic extraction of oxygen during anaesthesia in the dog

Measurement of hepatic oxygen extraction was performed on six healthy Greyhound dogs over a two hour period. The Greyhounds were anaesthetised and a right subcostal surgical incision performed. Ultrasonic flow transducers were used to measure flow rate in the hepatic artery and the portal vein. The blood oxygen tensions in arterial blood and in the portal and hepatic veins were also measured. Hepatic oxygen extraction remained stable throughout the study, despite a steady decline in arterial blood pressure. The methodology described in this study provides a direct measure of oxygen uptake by the liver in the dog and could readily be used to investigate hepatic uptake of drugs.     

CONTRAST‐ENHANCED ULTRASONOGRAPHIC CHARACTERISTICS OF ADRENAL GLANDS IN DOGS WITH PITUITARY‐DEPENDENT HYPERADRENOCORTICISM

A noninvasive method for quantifying adrenal gland vascular patterns could be helpful for improving detection of adrenal gland disease in dogs. The purpose of this retrospective study was to compare the contrast‐enhanced ultrasound (CEUS) characteristics of adrenal glands in 18 dogs with pituitary‐dependent hyperadrenocorticism (PDH) vs. four clinically healthy dogs. Each dog received a bolus of the contrast agent (SonoVue®, 0.03 ml/kg of body weight) into the cephalic vein, immediately followed by a 5 ml saline flush. Dynamic contrast enhancement was analyzed using time–intensity curves in two regions of interest drawn manually in the caudal part of the adrenal cortex and medulla, respectively. In healthy dogs, contrast enhancement distribution was homogeneous and exhibited increased intensity from the medulla to the cortex. In the washout phase, there was a gradual and homogeneous decrease of enhancement of the adrenal gland. For all dogs with PDH, there was rapid, chaotic, and simultaneous contrast enhancement in both the medulla and cortex. Three distinct perfusion patterns were observed. Peak perfusion intensity was approximately twice as high (P < 0.05) in dogs with PDH compared with that of healthy dogs (28.90 ± 10.36 vs. 48.47 ± 15.28, respectively). In dogs with PDH, adrenal blood flow and blood volume values were approximately two‐ to fourfold (P < 0.05) greater than those of controls. Findings from the present study support the use of CEUS as a clinical tool for characterizing canine adrenal gland disease based on changes in vascular patterns.     

Using 20-gauge percutaneous peripheral catheters to reliably collect serial 4-mL blood samples from conscious dogs

Objective To determine the reliability of collecting serial 4-mL blood samples over 13 h using a 20-gauge, cephalic catheter in conscious dogs. Design Prospective, observational study. Animals Twelve (6 males, 6 females) healthy, neutered, lean dogs. Procedure Percutaneous placement of a 20-gauge, 1.1 × 30 mm intravenous over-the-needle catheter into the cephalic vein was performed in each dog on three occasions. Catheter patency was maintained by intermittent flushing with 0.9% saline and 1 IU/mL heparinised saline solutions. Blood samples (4 mL) were obtained at 10 time-points over 13 h, with close monitoring of the dogs and the indwelling catheters. Blood volume, resistance on aspirating blood sample (minimal or marked resistance) and the methods used to improve blood flow were recorded. Results A high proportion (93%) of blood sample collections achieved the required 4-mL volume, and the remaining samples were greater than 1.5 mL. Of the 358 collections via the cephalic catheter, 311 (87%) were obtained with ‘minimal resistance’. The remaining collections had ‘marked resistance’ (n=47) and were associated with a loose catheter in 11% (5/47) and of unknown cause in 89% (42/47). After ‘marked resistance’ had been encountered and the catheter was flushed with saline and heparin solutions, subsequent sampling with ‘minimal resistance’ was frequently possible from the same catheter. Conclusion Use of a percutaneous, 20-gauge intravenous cephalic catheter allowed reliable serial collection of 4-mL blood samples over 13 h in conscious dogs.     

Congenital Interruption of the Portal Vein and Caudal Vena Cava in Dogs: Six Case Reports and a Review of the Literature

Objective —To describe six dogs with congenital abnormalities involving the portal vein, caudal vena cava, or both.
Animals —Six client-owned dogs with congenital interruption of the portal vein or the caudal vena cava, or both.
Methods —Portal vein and caudal vena cava anatomy was evaluated by contrast radiography and visualization at surgery. Vascular casts or plastinated specimens were obtained in three animals.
Results —Portal blood shunted into the caudal vena cava in four dogs and the left hepatic vein in one. Two of these five dogs also had interruption of the caudal vena cava with continuation as azygous vein, as did an additional dog, in which the portal vein was normally formed. Portal vein interruption was present in 5 of 74 (6.8%) dogs with congenital portosystemic shunts evaluated at the Veterinary Teaching Hospital during the study period.
Conclusions —Serious malformations of the abdominal veins were present in more than 1 in 20 dogs with single congenital portosystemic shunts.
Clinical Relevance —Veterinarians involved in diagnosis and surgery for portosystemic shunts should be aware of these potential malformations, and portal vein continuity should be evaluated in all dogs before attempting shunt attenuation.     

Veins of the thoracic limb of the Van cat

The drainage of the thoracic limb of the Van cat was performed by the superficial and deep vein systems. The superficial system was constituted by the cephalic vein and its branches. The deep vein system was constituted by the axillary vein and its branches. The two vein systems anastomosed with each other at various points along their courses. The cephalic vein emerged from the external jugular vein together with the superficial cervical vein. The axillary vein continued the subclavian vein. It ran caudoventrally and gave off the subscapular vein, at the level of the shoulder joint, then gave off two independent branches, which were the external thoracic veins. Then the rest of the vessel continued as the brachial vein. The thoracodorsal vein was formed by the communicate ramus vein which arose between the subscapular vein and the brachial vein. The cranial circumflex humeral vein arose double from the subscapular vein. One of them anastomosed with the deep brachial vein and the other one drained the biceps and the deep pectoral muscles. The cranial interosseous vein from the caudal aspects of the brachial vein and passed the interosseous space of the antebrachium then ran to the lateral aspect of the forearm. The caudal interosseous vein arose from the ulnar vein (in two specimens) and the median vein together with the ulnar vein (in two specimens) or independently from the median vein (in one specimen). Although many similarities were found in the veins of the thoracic limb of the Van cat as compared with the domestic cat, some significant differences were noted in the origin, course, anastomosing and ramification of veins of the thoracic limb.     

Computed tomography findings in portal vein aneurysm of dogs

In this retrospective study, the appearances of extrahepatic and intrahepatic portal vein aneurysms (PVAs) in dogs were evaluated using multidetector computed tomography (CT). Data from 3060 dogs that underwent abdominal CT were reviewed for focal portal vein dilatation. PVAs were detected in 15/3060 (0.49%) dogs. The bodyweights of dogs with PVAs were significantly higher than the bodyweights of dogs without aneurysms (P=0.0001). Male sex was also significantly associated with PVAs (OR=6.23). Boxers were predisposed to the development of PVA (OR=11.88). Extrahepatic PVAs were always located in the portal vein at the level of the gastroduodenal vein insertion and were saccular in 10/15 dogs and fusiform in 5/15 dogs. One dog had an additional intrahepatic aneurysm of the umbilical part of the left intrahepatic portal branch. No dogs had clinical signs related to the PVA(s), although one dog developed a portal vein thrombosis in the site of the aneurysm.     

The venous supply of the cecum, ileum, and the proximal loop of the ascending colon in the ox

The present study describes in detail the venous supply to the bovine cecum, ileum, and the proximal loop of the ascending colon. The cecum was supplied by branches from the cecal and accessory cecal veins. The accessory cecal vein was observed in the majority of the specimens examined. The cecal and accessory cecal veins were joined by 7–10 short oblique anastomoses. The ileum was supplied by the ileal branches of the cecal vein, and from the mesenteric ileal and first ileal (cranial mesenteric) veins. The ileal branches of the cecal vein formed a row of antimesenteric ileal arches in the ileal part of the ileocecal fold. The mesenteric ileal vein, in some cases, detached a collateral branch. The first ileal and the mesenteric ileal veins anastomosed on the ventral surface of the ileum. The initial loop of colon was supplied by branches from the ileocolic vein. In the majority of specimens, the common colic, a branch of the cranial mesenteric vein, supplied the first colic branch to the third part of the initial colon. In such cases, the ileocolic vein gave off only the second and third colic branches. However, in one case, the proximal loop of the ascending colon was supplied by three colic branches of the ileocolic vein and by the first colic branch of the common colic vein. In specimens in which the common colic vein was absent, the colic branches to the initial colon were all given off by the ileocolic vein. The third (or fourth) colic branch of the ileocolic vein and the first cecal branch of the cecal vein united on the lateral surface of the ileocecocolic junction to form an ileocecocolic arch. The veins on the medial surface of the ileocecocolic junction did not form an arch. The colic and ileal lymph nodes were supplied by twigs from the colic branches of the ileocolic vein and first ileal vein of the cranial mesenteric, respectively. The small cecal lymph nodes seen only in the specimen from the calf were supplied by fine branches from the cecal vein.     

Hemodynamic evaluation of the right portal vein in healthy dogs of different body weights

Background

Doppler ultrasonography is an important tool for evaluating hepatic portal hemodynamics. However, no study in dogs of different body weights, in the range encountered in routine clinical veterinary practice, has been reported. It can be difficult to obtain an ideal insonation angle when evaluating the main portal vein, so evaluation of the right portal vein branch has been described in humans as an alternative. The aim of this study was to analyze, through Doppler ultrasonography, the hemodynamics in the right portal vein branch in dogs of different body weights.

Methods

Thirty normal dogs were divided in three groups by weight, in order to establish normal values for mean velocity, flow volume and portal congestion index of the right portal vein branch by means of Doppler ultrasonography.

Results

In all dogs ideal insonation angles were obtained for the right portal vein branch. The average velocity was similar in the three groups, but the portal congestion index and the flow volume differed, showing that the weight of the dog can influence these values.

Conclusion

Doppler ultrasonography for the evaluation of flow in the right branch of the portal vein could be a viable alternative, or complement, to examining the main vessel segment. This is especially so in those animals in which an ideal insonation angle for examination of the main portal vein is hard to obtain. In addition, the weight of the dog must be considered for the correct evaluation of the portal system hemodynamics, particularly for portal blood flow and the congestion index.