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.     

Clinical safety of percutaneous ultrasound‐guided fine‐needle aspiration of adrenal gland lesions in 19 dogs

Objective

To evaluate the safety of fine‐needle aspiration of adrenal gland lesions in dogs and to characterise the risks in a subset of patients with cytologically or histopathologically diagnosed phaeochromocytoma.

Materials and Methods

Retrospective review of medical records of dogs that underwent percutaneous ultrasound‐guided fine‐needle aspiration of adrenal gland lesions between August 2014 and December 2016. Nineteen dogs were identified, with three undergoing bilateral adrenal gland aspiration and one dog undergoing aspiration twice, yielding 23 cytology samples in total. Data collected included signalment, concurrent medical conditions, current medications, blood pressure and heart rate before adrenal fine‐needle aspiration, imaging characteristics of the adrenal gland lesions and any clinically apparent procedure‐related complications.

Results

Phaeochromocytoma was diagnosed in nine of 19 dogs, including one dog with bilateral phaeochromocytoma. One dog developed ventricular tachycardia following aspiration of an adrenal gland lesion cytologically consistent with a phaeochromocytoma.

Clinical Significance

Percutaneous ultrasound‐guided fine‐needle aspiration of adrenal gland lesions appears to be relatively safe, even in phaeochromocytoma, but further data are required to lend more weight to this finding. Minimally invasive aspirates could be considered as part of the diagnostic algorithm in the investigation of an incidentally detected adrenal gland lesion of uncertain clinical significance.     

Comparison of ultrasonic Doppler flow monitor,oscillometric, and direct arterial blood pressure measurements in ill dogs

Objective – To compare blood pressure measurements obtained via ultrasonic Doppler flow monitor (DOP) and 2 oscillometric noninvasive blood pressure monitors (CAR and PAS) to invasive blood pressure (IBP) in hospitalized, conscious dogs with a range of blood pressures. Design – Prospective clinical study. Setting – University teaching hospital. Animals – Eleven client‐owned dogs aged between 4 months and 11.5 years (median 6 y), and weighing between 5.8 and 37.5 kg (median 30.2 kg). Interventions – Blood pressure measurement. Measurements and Main Results – Three consecutive measurements of systolic, diastolic, and mean arterial pressure (MAP) were recorded for each of the 3 indirect devices (only systolic for DOP), along with concurrent IBP measurements. The data were categorized into 3 groups: hypotensive (direct MAP<80 mm Hg), normotensive (80 mm Hg≤direct MAP≥100 mm Hg), and hypertensive (direct MAP>100 mm Hg). Each indirect method was compared with the corresponding direct arterial pressure using the Bland‐Altman method. Within the hypotensive group, each indirect method overestimated the corresponding IBP. Within the normotensive group all indirect systolic measurements and the PAS diastolic measurements underestimated the corresponding IBP. The remaining indirect measurements overestimated the corresponding IBP. Within the hypertensive group, DOP and CAR systolic measurements underestimated the corresponding IBP, and the remaining indirect measurements overestimated the corresponding IBP. In hypertensive dogs oscillometric systolic measurements were more accurate than MAP. In hypotensive dogs MAP measurements were more accurate than systolic measurements. All indirect measurements were most accurate in hypertensive dogs. Conclusions – The noninvasive blood pressure monitors in our study did not meet the validation standards set in human medicine. However, CAR diastolic and MAP measurements within the normotensive group, CAR MAP measurements within the hypertensive group, and PAS diastolic measurements in all groups were close to these standards. All indirect measurements showed greater bias during hypotension. Precision was poorer for all indirect systolic measurements than for MAP.     

Use of needle enhancing software to improve injection technique amongst inexperienced anaesthetists performing ultrasound‐guided peripheral nerves blocks in dogs

ObjectiveTo determine if the use of needle enhancing software facilitate injection technique in ultrasound‐guided peripheral nerve blocks.Study designProspective, blinded, randomized controlled trial.AnimalsEight hind limbs from canine cadavers.MethodsThe limbs were randomly allocated to two groups; software on (group I) and software off (group II). Eight anaesthetists with no previous experience of ultrasound‐guided regional anaesthesia were recruited. Thirty‐six procedures were carried out (18 per group). After sciatic nerve visualisation via ultrasonography, the anaesthetist introduced a needle guided by ultrasonography. When the tip of the needle was considered by the anaesthetist to be as close as possible to the nerve without touching it, 0.05 mL of methylene blue dye was injected. Parameters evaluated included: number of attempts to visualise the needle with ultrasonography, time spent to perform the technique, subjective evaluation of ease of needle visualisation, proximity of the tip of the needle to the nerve, and, at dissection of the leg, inoculation site of the dye in relation to the nerve.ResultsSignificant differences between groups were identified in relation to the number of attempts (group I: median 1, IQR: 1 – 1 attempts versus group II: median 1, IQR: 1 – 4 attempts, p = 0.019), and the relationship between the dye and the nerve during hind limb dissection (72.2% of the nerves were stained in group I versus 16.6% in group II,p = 0.003). No significant difference between groups was observed with respect to the time taken to perform the procedure (group I: median 25.5, IQR: 18.4 – 44.3 seconds versus group II: median 35.7, IQR: 18.6–78.72 seconds, p = 0.31), subjective evaluation of the needle visualization (p = 0.45) or distance between the tip of the needle and the nerve as measured from the ultrasound screen (p = 0.23).Conclusions and clinical relevanceThis study identified greater success rate in nerve staining when the needle enhancing software was used. The results suggest that the use of this technique could improve injection technique amongst inexperienced anaesthetists performing ultrasound‐guided peripheral nerve blocks in dogs.     

Analysis of a commercial dimethyl‐sulfoxide‐stabilized frozen canine platelet concentrate by turbidimetric aggregometry

Objectives – To assess platelet function of a commercial dimethyl‐sulfoxide (DMSO)‐stabilized frozen platelet concentrate (PC) using turbidimetric aggregometry. Design – In vitro analysis. Setting – Research laboratory in a school of veterinary medicine. Animals – Five units of frozen PC in 6% DMSO were studied. Fresh platelet‐rich plasma (PRP), with and without 6% DMSO, from 6 healthy dogs were used as controls. Interventions – Turbidimetric platelet aggregation was measured after initiation of platelet aggregation by addition of adenosine diphosphate (ADP), collagen, or thrombin at concentrations of 30 μM, 20 μg/mL, and 0.5 U/mL, respectively. Measures were performed at thaw and repeated 2 hours after thaw for the frozen PC. Measurements and Main Results – Compared with PRP, the frozen PC showed decreased aggregation in response to thrombin (amplitude of 84% versus 25%, P=0.01), and collagen (amplitude of 13% versus 3%, P=0.05) but not ADP (6.5% versus 18%, P=0.2). Compared with frozen PC at thaw, the frozen PC at 2 hours after thaw showed decreased aggregation in response to thrombin, collagen, and ADP (P<0.05). There was no difference in aggregation between PRP in 6% DMSO and frozen PC. Conclusions – These in vitro data suggest there is a decrease in platelet response to agonists associated with the freeze‐thaw process in the commercially available 6% DMSO canine frozen PC.     

Evaluation of acute congestive heart failure in dogs and cats: 145 cases (2007–2008)

Objective – To characterize the clinical presentation, management, and in‐hospital outcomes of dogs and cats diagnosed with acute congestive heart failure (CHF). Design – Retrospective study of animals seen between January 2007 and May 2008. Setting – Emergency service at a university teaching hospital. Animals – Ninety dogs and 55 cats with CHF. Measurements and Main Results – Patient characteristics, including age, clinical signs, clinicopathologic abnormalities, diagnostic testing, and outcome were recorded. Forty‐eight of the animals already were receiving cardiac medications at the time of presentation. The most common diseases represented were chronic valvular disease and cardiomyopathies. Cats had significantly lower median body temperature at admission compared with dogs (P<0.001). The most common abnormalities were elevated lactate (64%), elevated BUN (52%), hypochloremia (31%), hyperglycemia (27%), and elevated liver enzymes (26%). Many of these became even more prevalent during hospitalization. One hundred and sixteen animals were discharged from the hospital, for a survival rate of 80%. There was no survival difference between dogs and cats (P=0.39). Dogs that developed hypokalemia during hospital stay (P=0.04) were more likely to survive compared with those without hypokalemia and initial body temperature was lower for those cats that did not survive (P=0.02). Of those that did not survive, the majority were euthanized (n=25), while 4 dogs died. Conclusions – Dogs and cats presented to the emergency service with CHF had a high survival rate. In cats, initial body temperature was lower for those cats that did not survive. Although clinicopathologic abnormalities were common in both species, only dogs with hypokalemia had improved survival to hospital discharge.