Effects of hematocrit and red blood cell-independent viscosity on canine thromboelastographic tracings.

BACKGROUND: It is well established that hematocrit (Hct) influences whole blood thromboelastography (TEG) tracings. Previous studies showed hypercoagulable TEG tracings in anemic patients despite clinical expectations that anemia often prolongs bleeding. TEG is a viscoelastic assessment of clot kinetics, and Hct is the main determinant of whole blood viscosity. TEG changes in anemia may be an in vitro artifact due to Hct effect on blood viscosity rather than true in vivo changes in hemostasis. The effect of changes in whole blood viscosity on TEG independent of Hct is not well understood. STUDY DESIGN AND METHODS: Twenty-one blood samples from seven dogs were manipulated to produce one of three Hct conditions (45, 20, and 10%). Each was tested in two situations: viscosity adjusted to normal by adding alginate (ALG) or dilution with equal volume of saline (SAL). Both samples were analyzed with TEG simultaneously. RESULTS: Twenty percent Hct plus ALG and 10% Hct plus ALG were significantly more viscous than their SAL counterparts (p=0.0156). Ten percent Hct plus SAL, 20% Hct plus SAL, and 45% Hct plus SAL all had different viscosities (p=0.006). Twenty percent Hct plus SAL and 10% Hct plus SAL had significantly shorter K and higher angle, MA, and G compared to their ALG counterparts as well as 45% Hct plus SAL (p<0.05). CONCLUSIONS: ALG samples with low Hct, normal viscosity showed hypocoagulable tracings, whereas SAL samples with low Hct, low viscosity showed hypercoagulable tracings. TEG variables are influenced by whole blood viscosity altered with ALG, independently of Hct.

Association between the COVID-19 global pandemic and the prevalence of cats presenting with urethral obstruction at two university veterinary emergency rooms.

OBJECTIVES: The aim of this study was to investigate a potential association between the COVID-19 pandemic stay-at-home orders and the prevalence of emergency room presentations for urethral obstruction (UO) in feline patients. METHODS: Medical records and hospital census were retrospectively searched to identify the total number of cats and total number of male cats with UO presenting to two academic veterinary medical centers from 22 March to 10 August in the years 2018 (123), 2019 (137) and 2020 (175). Cats were grouped based on the year of presentation and the proportions of UO cases relative to all cats presenting to the emergency rooms during the same time frame. Absolute (year of interest - reference year) and relative ([year of interest - reference year]/[reference year]) change in prevalence was determined. These were compared for each year using a two-sample z-test. RESULTS: The absolute and relative prevalence of UO presentations across the combined population increased significantly during the COVID-19 pandemic in comparison with 2018 (2.2% and 59%, respectively; P = 0.0003) and 2019 (1.9% and 48%, respectively; P = 0.0021). For the individual institutions, a significant increase in UO presentations was found for institution A when comparing 2020 with both 2018 (P = 0.0072) and 2019 (P = 0.0073), but not for institution B (P = 0.057 and P = 0.18, respectively). No significant differences were found when 2018 and 2019 were compared across the combined population or within institutions. CONCLUSIONS AND RELEVANCE: The results of this study demonstrate an increased prevalence of UO during the initial months of the COVID-19 pandemic, which may be related to environmental change and stress imposed by stay-at-home orders.

Possible development and resolution of dilated cardiomyopathy phenotype secondary to atypical hypoadrenocorticism in a dog.

OBJECTIVE: To report the possible occurrence of dilated cardiomyopathy phenotype associated with atypical hypoadrenocorticism and subsequent marked improvement with treatment in a mixed breed dog. CASE SUMMARY: A 4.5-year-old, neutered male mixed breed dog was evaluated for a history and clinicopathological changes consistent with atypical hypoadrenocorticism. The dog was being fed a grain-free diet. While hospitalized for supportive care and diagnostics, the patient developed and was diagnosed with biventricular congestive heart failure secondary to dilated cardiomyopathy phenotype and IV fluid administration. The left-sided congestive heart failure resolved with discontinuation of IV fluid therapy and short-term administration of diuretics. After treatment of atypical hypoadrenocorticism with glucocorticoid supplementation, and while continuing to be fed varying grain-free diets, the patient's dilated cardiomyopathy phenotype largely resolved. The patient fully recovered and did not require any long-term cardiac medications. NEW OR UNIQUE INFORMATION PROVIDED: Development of dilated cardiomyopathy phenotype has not been described in dogs as a sequela of untreated hypoadrenocorticism but has been reported in human literature. Given the fact that standard management of hypoadrenocorticism typically involves aggressive fluid resuscitation, awareness of this potential sequela is important for patients that fail to respond or develop signs consistent with volume overload.

Preliminary study evaluating the assessment of changes in pulmonary function associated with body positioning in dogs with suspected aspiration pneumonia.

OBJECTIVE: To evaluate the variability in arterial blood gas (ABG) assessment of pulmonary function with different body positioning in dogs with suspected aspiration pneumonia. KEY FINDINGS: The median differences in alveolar-arterial gradient, Pao2 , and Paco2 values in different recumbencies were not statistically significantly different, both within patients and across the study population. No difference was noted in ABG values in the subgroups with unilateral or bilateral disease or that were more affected on the right side versus the left side. SIGNIFICANCE: This preliminary study provides data that can be used to calculate appropriate sample sizes for subsequent studies investigating the impact of recumbency on pulmonary function in patients with aspiration pneumonia.

Thromboelastographic results and hypercoagulability in dogs with surgically treated hepatocellular adenoma and carcinoma: A Veterinary Society of Surgical Oncology prospective study.

BACKGROUND: The most common haemostatic abnormality in dogs with cancer is hypercoagulability. A transient hypercoagulability has been documented in people with hepatocellular carcinoma (HCC) that resolves within weeks following hepatic tumour resection. OBJECTIVE: The objective was to compare the haemostatic status of dogs with liver tumours and healthy control dogs, by comparing coagulation and thromboelastography (TEG) measurements at three time points. METHODS: Liver tumour and healthy control dogs receiving surgery for liver lobectomy and ovariohysterectomy, respectively, were prospectively enrolled. All dogs had blood collected at three time points: pre-operative, 24 h post-operative and ~2 weeks post-operative. Haematological and haemostatic values were compared across time points in each group using repeated measures ANOVA tests. RESULTS: Ten and eight dogs were enrolled for the liver and control groups, respectively. Platelet count was significantly higher in the liver group than the control group at all time points, but within the normal range (pre-operative: 438.7 vs. 300.9 × 109 /L, p = .0078; 24 h post-operative: 416.2 vs. 283.9 × 109 /L, p = .0123; 10-14 days post-operative: 524.6 vs. 317.3 × 109 /L, p = .0072). The measure of the overall coagulant state (G-value) was significantly increased for the liver group compared to the control group at all time points (pre-operative: 15.6 vs. 8.6 d/sc, p = .0003; 24 h post-operative: 18.3 vs. 11.2 d/sc, p = .039; 10-14 days post-operative: 15.1 vs. 9.6 d/sc, p = .015). CONCLUSION: The liver group was hypercoagulable based on elevated G-values at all time points compared to the control group. This hypercoagulability was attributed to the effect of hepatic tumours alone, and not secondary to surgery and anaesthesia.

Impact of cytidine diphosphocholine on oxygenation in client-owned dogs with aspiration pneumonia.

BACKGROUND: New drugs for veterinary patients with acute respiratory distress syndrome (ARDS) are urgently needed. Early or late postinfection treatment of influenza-infected mice with the liponucleotide cytidine diphosphocholine (CDP-choline) resulted in decreased hypoxemia, pulmonary edema, lung dysfunction, and inflammation without altering viral replication. These findings suggested CDP-choline could have benefit as adjunctive treatment for ARDS in veterinary patients (VetARDS). OBJECTIVES: Determine if parenterally administered CDP-choline can attenuate mild VetARDS in dogs with aspiration pneumonia. ANIMALS: Dogs admitted to a veterinary intensive care unit (ICU) for aspiration pneumonia. METHODS: Subjects were enrolled in a randomized, double-blinded, placebo-controlled trial of treatment with vehicle (0.1 mL/kg sterile 0.9% saline, IV; n = 8) or CDP-choline (5 mg/kg in 0.1 mL/kg 0.9% saline, IV; n = 9) q12h over the first 48 hours after ICU admission. RESULTS: No significant differences in signalment or clinical findings were found between placebo- and CDP-choline-treated dogs on admission. All dogs exhibited tachycardia, tachypnea, hypertension, hypoxemia, hypocapnia, lymphopenia, and neutrophilia. CDP-choline administration resulted in rapid, progressive, and clinically relevant increases in oxygenation as determined by pulse oximetry and ratios of arterial oxygen partial pressure (Pa O2 mmHg) to fractional inspired oxygen (% Fi O2 ) and decreases in alveolar-arterial (A-a) gradients that did not occur in placebo (saline)-treated animals. Treatment with CDP-choline was also associated with less platelet consumption over the first 48 hours, but had no detectable detrimental effects. CONCLUSIONS AND CLINICAL IMPORTANCE: Ctyidine diphosphcholine acts rapidly to promote gas exchange in dogs with naturally occurring aspiration pneumonia and is a potential adjunctive treatment in VetARDS patients.

Assessment of microcirculatory changes by use of sidestream dark field microscopy during hemorrhagic shock in dogs.

OBJECTIVE: To directly assess microcirculatory changes associated with induced hemorrhagic shock by use of sidestream dark field microscopy (SDM) and correlate those values with concurrently measured macrovascular and blood gas variables in healthy anesthetized dogs. ANIMALS: 12 adult dogs. PROCEDURES: Dogs were anesthetized and splenectomized. Instrumentation and catheterization were performed for determination of macrohemodynamic and blood gas variables. Hemorrhagic shock was induced via controlled hemorrhage to a mean arterial blood pressure (MAP) of 40 mm Hg. Dogs were maintained in the shock state (MAP, 35 to 45 mm Hg) for 60 minutes. An SDM device was used to image microcirculation of buccal mucosa, and vascular analysis software was used to determine microcirculatory variables. These values were compared with other cardiovascular and blood gas variables to determine correlations. RESULTS: Following hemorrhage, there was a significant decrease in microvascular variables (mean ± SD), including proportion of perfused vessels (82.77 ± 8.32% vs 57.21 ± 28.83%), perfused vessel density (14.86 ± 2.64 mm/m(2) vs 6.66 ± 4.75 mm/m(2)), and microvascular flow index (2.54 ± 0.52 vs 1.59 ± 0.85). Perfused vessel density individually correlated well with macrovascular variables, with heart rate (zero order, partial correlation, and part correlation coefficients = -0.762, -0.884, and -0.793, respectively) and oxygen extraction ratio (-0.734, -0.832, and -0.746, respectively) being the most important predictors. CONCLUSIONS AND CLINICAL RELEVANCE: SDM allowed real-time imaging of the microvasculature and has potential as an effective tool in experimental and clinical applications for monitoring microcirculatory changes associated with hemorrhagic shock and resuscitation in dogs.

Fluid Therapy and the Microcirculation in Health and Critical Illness.

Fluid selection and administration during shock is typically guided by consideration of macrovascular abnormalities and resuscitative targets (perfusion parameters, heart rate, blood pressure, cardiac output). However, the microcirculatory unit (comprised of arterioles, true capillaries, and venules) is vital for the effective delivery of oxygen and nutrients to cells and removal of waste products from the tissue beds. Given that the microcirculation is subject to both systemic and local control, there is potential for functional changes and impacts on tissue perfusion that are not reflected by macrocirculatory parameters. This chapter will present an overview of the structure, function and regulation of the microcirculation and endothelial surface layer in health and shock states such as trauma, hemorrhage and sepsis. This will set the stage for consideration of how these microcirculatory characteristics, and the potential disconnect between micro- and macrovascular perfusion, may affect decisions related to acute fluid therapy (fluid type, amount, and rate) and monitoring of resuscitative efforts. Available evidence for the impact of various fluids and resuscitative strategies on the microcirculation will also be reviewed.

Successful management of massive lamotrigine extended-release intoxication in a dog.

A 3-year-old spayed female Siberian Husky presented for evaluation following ingestion of approximately 429 mg/kg of lamotrigine extended-release. She demonstrated severe neurologic and cardiac signs and was treated with lipid emulsion, anticonvulsants, antiarrhythmics and aggressive decontamination and supportive care. She was successfully discharged from the hospital 5 days later.

Multicenter evaluation of decompressive cystocentesis in the treatment of cats with urethral obstruction.

OBJECTIVE: To investigate whether decompressive cystocentesis (DC) safely facilitates urethral catheterization (UC) in cats with urethral obstruction (UO). ANIMALS: 88 male cats with UO. PROCEDURES: Cats were randomly assigned to receive DC prior to UC (ie, DC group cats; n = 44) or UC only (ie, UC group cats; 44). Abdominal effusion was monitored by serial ultrasonographic examination of the urinary bladder before DC and UC or before UC (DC and UC group cats, respectively), immediately after UC, and 4 hours after UC. Total abdominal effusion score at each time point ranged from 0 (no effusion) to 16 (extensive effusion). Ease of UC (score, 0 [easy passage] to 4 [unable to pass]), time to place urinary catheter, and adverse events were recorded. RESULTS: No significant difference was found in median time to place the urinary catheter in UC group cats (132 seconds), compared with DC group cats (120 seconds). Median score for ease of UC was not significantly different between UC group cats (score, 1; range, 0 to 3) and DC group cats (score, 1; range, 0 to 4). Median change in total abdominal effusion score from before UC and DC to immediately after UC was 0 and nonsignificant in UC group cats (range, -5 to 12) and DC group cats (range, -4 to 8). Median change in effusion score from immediately after UC to 4 hours after UC was not significantly different between UC group cats (score, -1; range, -9 to 5) and DC group cats (score, -1; range, -7 to 5). CONCLUSIONS AND CLINICAL RELEVANCE: DC did not improve time to place the urinary catheter or ease of UC in cats with UO.

Resuscitation Patterns and Massive Transfusion for the Critical Bleeding Dog-A Multicentric Retrospective Study of 69 Cases (2007-2013).

Objective: To describe resuscitation patterns of critically bleeding dogs, including those receiving massive transfusion (MT). Design: Retrospective study from three universities (2007-2013). Animals: Critically bleeding dogs, defined as dogs who received ≥ 25 ml/kg of blood products for treatment of hemorrhagic shock caused by blood loss. Measurements and Main Results: Sixty-nine dogs were included. Sources of critical bleeding were trauma (26.1%), intra/perioperative surgical period (26.1%), miscellaneous (24.6%), and spontaneous hemoabdomen (23.1%). Median (range) age was 7 years (0.5-18). Median body weight was 20 kg (2.6-57). Median pre-transfusion hematocrit, total protein, systolic blood pressure, and lactate were 25% (10-63), 4.1 g/dl (2-7.1), 80 mm Hg (20-181), and 6.4 mmol/L (1.1-18.2), respectively. Median blood product volume administered was 44 ml/kg (25-137.4). Median plasma to red blood cell ratio was 0.8 (0-4), and median non-blood product resuscitation fluid to blood product ratio was 0.5 (0-3.6). MT was given to 47.8% of dogs. Survival rate was 40.6%. The estimated odds of survival were higher by a factor of 1.8 (95% CI: 1.174, 3.094) for a dog with 1 g/dl higher total protein above reference interval and were lower by a factor of 0.6 (95% CI: 0.340, 0.915) per 100% prolongation of partial thromboplastin time above the reference interval. No predictors of MT were identified. Conclusions: Critical bleeding in dogs was associated with a wide range of resuscitation patterns and carries a guarded to poor prognosis.

A protocol for managing urethral obstruction in male cats without urethral catheterization.

OBJECTIVE: To determine efficacy of a protocol for managing urethral obstruction (UO) in male cats without urethral catheterization. DESIGN: Clinical trial. ANIMALS: 15 male cats with UO in which conventional treatment had been declined. PROCEDURES: Laboratory testing and abdominal radiography were performed, and cats with severe metabolic derangements or urinary calculi were excluded. Treatment included administration of acepromazine (0.25 mg, IM, or 2.5 mg, PO, q 8 h), buprenorphine (0.075 mg, PO, q 8 h), and medetomidine (0.1 mg, IM, q 24 h) and decompressive cystocentesis and SC administration of fluids as needed. Cats were placed in a quiet, dark environment to minimize stress. Treatment success was defined as spontaneous urination within 72 hours and subsequent discharge from the hospital. RESULTS: Treatment was successful in 11 of the 15 cats. In the remaining 4 cats, treatment was considered to have failed because of development of uroabdomen (n=3) or hemoabdomen (1). Cats in which treatment failed had significantly higher serum creatinine concentrations than did cats in which treatment was successful. Necropsy was performed on 3 cats in which treatment had failed. All 3 had severe inflammatory disease of the urinary bladder, but none had evidence of bladder rupture. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that in male cats, a combination of pharmacological treatment, decompressive cystocentesis, and a low-stress environment may allow for resolution of UO without the need for urethral catheterization. This low-cost protocol could serve as an alternative to euthanasia when financial constraints prevent more extensive treatment.

Use of a unique method for removal of a foreign body from the trachea of a cat.

CASE DESCRIPTION: A 2.96-kg (6.5-lb) 9-month-old spayed female domestic longhair cat was admitted for removal of a tracheal foreign body. CLINICAL FINDINGS: The cat had moderate respiratory distress but otherwise appeared to be healthy. Thoracic radiography revealed a foreign body in the trachea. TREATMENT AND OUTCOME: The cat was anesthetized and endoscopy of the trachea was performed in an attempt to retrieve the foreign body. Endoscopic removal was unsuccessful because of the shape and smooth texture of the foreign body. Surgical removal of the foreign body was not considered ideal because of its location and the risks associated with tracheotomy. Fluoroscopic-guided placement of an over-the-wire balloon catheter caudal to the foreign body was followed by inflation of the balloon and gradual traction in an orad direction, which resulted in successful removal of the foreign body (identified as a piece of landscaping gravel). The cat required supplemental oxygen and supportive care following removal of the foreign body. CLINICAL RELEVANCE: A fluoroscopic technique was used as a minimally invasive alternative to endoscopy or open-chest surgery for removal of a foreign body from the trachea of a cat. Use of this technique allowed uninterrupted ventilation of the cat throughout the procedure.

Effect of packed red blood cell transfusion on thromboelastographic tracings in dogs with naturally occurring anemia.

OBJECTIVE: To assess the effect of packed RBC (pRBC) transfusion on thromboelastographic (TEG) tracings in dogs with naturally occurring anemia. ANIMALS: 22 clinically anemic dogs that received a pRBC transfusion. PROCEDURES: For each dog, a blood sample was collected before and within 3 hours after completion of the pRBC transfusion for a CBC, nonactivated TEG analysis, and measurement of blood viscosity. Wilcoxon signed rank tests were used to compare CBC, viscosity, and TEG variables between pretransfusion and posttransfusion blood samples. Multivariable linear regression was used to assess the effects of pretransfusion-posttransfusion changes in Hct, WBC count, and platelet count on changes in TEG variables. RESULTS: Median posttransfusion Hct (21%; range, 13% to 34%) was significantly greater than the median pretransfusion Hct (12.5%; range, 7% to 29%). Packed RBC transfusion was associated with a median increase in Hct of 6.2% (range, 1.2% to 13%). Maximum amplitude significantly decreased from 74.9 to 73.8 mm and clot strength significantly decreased from 14,906 to 14,119 dynes/s after pRBC transfusion. Blood viscosity significantly increased, whereas platelet and WBC counts significantly decreased after transfusion. Multivariable linear regression revealed that pretransfusion-posttransfusion changes in Hct, WBC count, and platelet count were not associated with changes in TEG variables. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that pRBC transfusion had only small effects on the TEG tracings of hemodynamically stable dogs. Therefore, large changes in TEG tracings following pRBC transfusion are unlikely to be the result of the transfusion and should be investigated further.

Association of abdominal effusion with a single decompressive cystocentesis prior to catheterization in male cats with urethral obstruction.

OBJECTIVE: To evaluate the occurrence of abdominal effusion and its association with decompressive cystocentesis in male cats with urethral obstruction. DESIGN: Prospective observational clinical study. ANIMALS: Forty-five male neutered, client-owned cats with naturally occurring urethral obstruction. PROCEDURES: Laboratory testing and point-of-care ultrasonography were performed. Presence of abdominal effusion was evaluated using the Focused Assessment with Sonography for Trauma (FAST) technique at presentation. Decompressive cystocentesis was then performed prior to catheterization by a standardized technique. Repeat FAST examination was performed 15 minutes after cystocentesis and the following day to further assess for the presence of abdominal effusion. RESULTS: A mean volume of 92.3 ± 35.2 mL of urine was removed from each cat via cystocentesis prior to catheterization. At presentation, 15 of 45 (33%) had abdominal effusion (13/15 with scant effusion, 2/15 with mild), with an additional 7 cats developing scant effusion 15 minutes post-cystocentesis. By the following day, 4 cats still had scant effusion present. No significant complications secondary to cystocentesis were reported. No association was found between severity of azotemia, or volume removed by cystocentesis, and the presence of effusion at presentation or after decompressive cystocentesis was performed. CONCLUSIONS AND CLINICAL RELEVANCE: A single decompressive cystocentesis prior to catheterization did not lead to development of clinically significant abdominal effusion or other discernable complications and appears to be a safe procedure in this population of patients. Abdominal effusion may be found at presentation in cats with urethral obstruction. The significance of this effusion remains to be determined.

Evaluation of hyperviscous fluid resuscitation in a canine model of hemorrhagic shock: a randomized, controlled study.

BACKGROUND: Enhancing plasma viscosity during fluid resuscitation results in vasodilation and improved microvascular perfusion in rodents subjected to hemorrhagic shock. We hypothesized that resuscitation with hyperviscous lactated Ringer's solution (hyperLRS) would result in improved tissue oxygenation and acid-base values in hemorrhaged dogs. METHODS: Twelve dogs were anesthetized and splenectomized. Vascular catheterization was performed, and tissue oxygen probes were placed in the jejunal serosa and skeletal muscle to assess macro- and microhemodynamic parameters. Baseline (BL) and posthemorrhage data were obtained. After 1 hour of hemorrhagic shock (mean arterial pressure [MAP] 30-40 mm Hg), treatment groups (n = 6) were administered bolus LRS or hyperLRS, and then received sufficient LRS to achieve and maintain an MAP between 60 mm Hg and 70 mm Hg. Data were obtained at 10, 30, 60, 120, and 180 minutes after fluid resuscitation. RESULTS: There were no significant differences between LRS or hyperLRS groups at BL or posthemorrhage. Blood and plasma viscosity were significantly increased by the administration of hyperLRS at all time points postresuscitation compared with LRS. Significantly more fluid was required to maintain MAP, and vascular hindrance was consistently lower in dogs administered hyperLRS versus LRS, suggesting viscosity-induced vasodilation. Central and mesenteric venous oxygen saturations were significantly decreased, whereas lactate and oxygen extraction ratios were significantly increased after hyperLRS administration compared with LRS. The tissue oxygen tension was similar in dogs administered hyperLRS or LRS. CONCLUSIONS: A hyperviscous balanced electrolyte solution did not improve hemodynamic parameters, tissue oxygen tension, or acid-base values despite evidence for viscosity-induced vasodilation.

Incidence of bacteriuria at presentation and resulting from urinary catheterization in feline urethral obstruction.

OBJECTIVE: To determine the incidence of bacteriuria at the time of presentation and as a result of indwelling urethral catheterization in naturally occurring feline urethral obstruction (UO). DESIGN: Prospective observational study. SETTING: University teaching hospital. ANIMALS: A population of 34 male cats with UO admitted for standard medical care. INTERVENTIONS: A presenting urine sample was obtained by cystocentesis (precatheterization). After catheterization (performed under strict aseptic technique), a urine sample was obtained through the urinary catheter every 24 hours, as well as just prior to catheter removal. Urine was applied to culture media within 30 minutes of collection or refrigerated immediately at 4°C for subsequent culture the following morning. Samples positive for growth (defined as > 104 colony forming units/mL) had bacterial identification and susceptibility testing performed. MEASUREMENTS AND MAIN RESULTS: All 34 cats enrolled had initial culture performed. Of these, 1 patient died and 2 were euthanized within 24 hours and therefore subsequent cultures were obtained. The remaining 31 cats had median catheterization time of 42 hours (range 20-110 hours). No urine cultures yielded growth at presentation (0/34). A total of 4 of 31 patients (13%) subsequently had bacterial cultures that yielded growth. In these cases, all yielded growth by the 24-hour time point, and all had the same organism identified on subsequent cultures. Identified bacteria included Streptococcus spp. (3) and Pasteurella spp. (1). CONCLUSIONS: The male cats with UO in this study did not have bacteriuria at the time of presentation. The overall incidence of acquired bacteriuria was found to be 13% and could represent a transient bacterial population or true bacterial urinary tract infection. Based on these findings, empirical administration of antibiotics is not warranted in male cats with UO.

Electrolyte, acid-base, and hemoglobin oxygen affinity alterations following irradiation and storage of canine packed red blood cells.

BACKGROUND: Irradiation of RBC before transfusion is required to prevent transfusion-associated graft-versus-host disease for human patients undergoing hematopoietic stem cell transplantation. Additional applications for irradiated blood may exist in oncologic surgery. The effect of irradiation on canine packed RBC (pRBC) is unknown. OBJECTIVES: The aim of this study was to explore and characterize the in vitro electrolyte, acid-base, and oxygen-carrying capacity changes to pRBC immediately following irradiation and during storage. METHODS: Ten units of pRBC were irradiated using a linear accelerator. Concentration of potassium and glucose, percentage of free hemoglobin (fHb), hemoglobin oxygen saturation (sO2 ), total oxygen content, partial pressure of oxygen (pO2 ), the pO2 at which 50% of hemoglobin is saturated (p50), lactate, pH, and methemoglobin were measured before and following irradiation, and at 7 and 17 days post irradiation. RESULTS: In both irradiated and nonirradiated units, a significant decrease in pH and glucose, and a significant increase in lactate and potassium were noted. The pO2 , fHb, and the p50 value in both groups increased over the first 7 days. Immediately following irradiation, the pH was significantly lower, and the potassium, lactate, and fHb were significantly higher in irradiated units compared with controls. Small but significant differences were noted between irradiation status in pH, fHb, sO2 , total oxygen content, and p50 value at 7 days post irradiation. CONCLUSIONS: This hypothesis-generating study found irradiation and storage significantly altered in vitro properties of pRBC. The magnitude of these differences was small and the clinical impact of irradiation on pRBC may be negligible.

Severe bronchoconstriction after bronchoalveolar lavage in a dog with eosinophilic airway disease.

Bronchoalveolar lavage (BAL) is considered to be a safe procedure in humans and other animals. However, in some instances, potentially life-threatening complications can arise. In this clinical report, a dog with eosinophilic airway disease that underwent a BAL and subsequently became profoundly dyspneic during the recovery period is described. The dyspnea was severe enough to warrant mechanical ventilation for almost 24 hours. Several anti-inflammatory and bronchodilatory medications were also used. The dog was successfully weaned off the ventilator and made a full recovery. On the basis of radiographic findings and clinical response to treatment, we believe the dog had acute exacerbation of eosinophilic airway disease and severe bronchoconstriction secondary to the BAL. Caution should be exercised when performing a BAL if there is suspicion of a reactive airway disease.

Controversies in the management of feline urethral obstruction.

OBJECTIVE: To discuss areas of differing opinion in the management of feline urethral obstruction and present current evidence to either support or refute common practices. ETIOLOGY: Urethral obstruction may occur as a result from a functional obstruction (idiopathic obstruction) or a physical obstruction, such as mucous plugs or calculi within the urethra. Potential risk factors for obstruction in cats include predominantly indoor status, decreased water intake, and increased body weight. DIAGNOSIS: The diagnosis is most commonly made based on history and initial physical exam-straining to urinate, vocalizing, signs of systemic illness, moderate to large firm bladder on abdominal palpation. THERAPY: Treatment is based on available evidence. The type of IV isotonic crystalloid used does not seem to matter and rate should be determined by need for fluid resuscitation, and replacement of deficit and ongoing losses. Though controversial, cystocentesis appears to be safe and may offer some benefits in initial management. There is evidence to suggest a smaller urethral catheter (3.5 Fr) may be associated with decreased risk of reobstruction. Routine use of antimicrobial agents in hospital is not recommended; they should be dispensed based on culture performed at the time of catheter removal. Though commonly used, evidence in support of antispasmodics is limited and further prospective investigation is needed. PROGNOSIS: Feline urethral obstruction is associated with 90-95% survival, with reported recurrence rates of 15-40%. Potential factors affecting recurrence include size or duration of indwelling urinary catheter, use of antispasmodic agents, patient age, and indoor-outdoor lifestyle; however, different studies offer conflicting results. Increased water intake and environmental modification do seem to decrease risk of recurrence.