Computer tomography measurements of the airway and thoracic cavity do not provide support for bronchial conformation as a predisposing factor of left cranial lung lobe torsion in pugs.

The objective of this retrospective clinical study was to determine if airway or thoracic cavity measurements in pugs, particularly the left cranial lung lobe, were significantly different from brachycephalic and mesocephalic control. Thoracic computed tomographic studies of 10 pugs, French bulldogs (FB), and Jack Russell Terriers (JRT) were analyzed. Thoracic height: width ratio (H:W), cross-sectional areas of the left mainstem bronchus (CSA LMB), left cranial lung lobe bronchus (CSA LCrBr), left caudal lung lobe bronchus (CSA LCauBr), CSA LCrBr relative to length (CSA LCrBr/length) and CSA LCauBr/length were measured and adjusted to body weight (/kg). CSA LMB/kg, CSA LCauBr/length/kg, and CSA LCrBr/length /kg were smaller in pugs and FB compared with JRT (P < .05), but no differences were found between pugs and FB. Cross-sectional areas of left cranial lung lobe bronchus /kg and CSA LCauBr/kg were smaller in pugs than JRT (P < .05), but no differences were found between pugs and FB or FB and JRT. No difference was found in thoracic H:W between any breeds. This demonstrated that pugs and FB had significantly narrower bronchi CSA/lengths ratios compared with JRT, but this was not limited to the LCBr. Airway measurements were not significantly different between brachycephalic breeds; therefore, the pugs' predisposition to left cranial lung lobe torsion cannot be solely explained by narrower lower airways.

What is the value of statistical testing of observational data?

Statistical analysis of medical data aims to reveal patterns that can aid in decision making for future cases and, hopefully, improve patient outcomes. Large and bias-free datasets, such as those produced in formal randomized clinical trials, are necessary to make such analyses as reliable as possible. For a host of reasons, randomized trials are, unfortunately, relatively uncommon in veterinary medicine and surgery, implying that less ideal datasets (mostly observational data) must form the basis for much of our decision making regarding treatment of individual patients under our care. In this review, we first describe the common shortcomings of many observational veterinary datasets when viewed in comparison with their optimal counterparts and highlight how the deficiencies can lead to unreliable conclusions. We illustrate how many of the interpretative problems associated with observational data, predominantly various forms of bias, are not solved, and may even be exacerbated, by statistical analysis. We emphasize the need to examine summary data and its derivation in detail without being lured into relying upon P values to draw conclusions and advocate for completely omitting statistical analysis of many observational datasets. Finally, we present some suggestions for alternative statistical methods, such as propensity scoring and Bayesian methods, which might help reduce the risk of drawing unwarranted, and overconfident, conclusions from imperfect data.

Long-term outcome of female dogs treated for intramural ectopic ureters with cystoscopic-guided laser ablation.

OBJECTIVE: To report the complications and long-term outcome of female dogs with intramural ectopic ureter(s) (iEU) undergoing cystoscopic-guided laser ablation (CLA) and determine the effect of post-CLA neutering on urinary continence. STUDY DESIGN: Retrospective clinical study. ANIMALS OR SAMPLE POPULATION: Thirty-four client-owned dogs. METHODS: Medical records of female dogs that had iEU-CLA were reviewed. A 10-point continence score was assigned before, immediately after, and at a minimum of 12 months postprocedure via owner telephone contact. Neutering status prior to and postprocedure was recorded. RESULTS: Continence scores increased in all dogs after CLA (p < .0001, mean duration of follow-up: 63.9 ± 5.7 months) with an increase of the median score from 2 (preprocedure) to 10 (postprocedure). A urethral tear occurred in 2/34 dogs immediately after the procedure, successfully managed conservatively. Mild hematuria was present in 2/34, lasting less than 48 h. Postoperative urinary tract infections were documented in 6/34 dogs. Two dogs died of urinary-related issues at 1 and 5 months after CLA. Complete and near-complete urinary continence (scores 9 and 10/10) was achieved in 26/32 dogs including 3 dogs requiring medical (2) or surgical interventions (1). Post-CLA neutering did not affect continence scores (p = .44). CONCLUSION: A large proportion of dogs regained and maintained full continence after CLA alone. Subsequent medical or surgical therapy allowed further improvements when needed. Post-CLA neutering did not negatively impact urinary continence score. CLINICAL SIGNIFICANCE: The beneficial effect of iEU-CLA in female dogs is long standing and not affected by postprocedural neutering.

Outcomes of dogs treated for extrahepatic congenital portosystemic shunts with thin film banding or ameroid ring constrictor.

OBJECTIVE: To compare the outcomes of dogs treated at a single institution for single extrahepatic congenital portosystemic shunts (CPSS) by thin film banding (TFB) or by placement of an ameroid constrictor (AC). STUDY DESIGN: Retrospective case series. ANIMALS: Seventy-six client-owned dogs with CPSS treated with TFB (n = 53) or AC (n = 23). METHODS: Records were reviewed for signalment, preoperative, intraoperative, and postoperative management and short-term outcomes. Data on second surgeries were reviewed. Long-term outcomes were obtained via an owner-directed health-related quality of life questionnaire. The rates of complications, mortality, and revision surgery were compared between the treatment groups. RESULTS: Postoperative complications occurred in 15 (28%) dogs with TFB (9% mortality, n = 5) and 8 (35%) dogs with an AC (4% mortality, n = 1). Long-term follow-up was available in 41 of 56 dogs at a median of 55 months (range, 15-89). Revision surgery for persistent shunting was performed in 14 (29%) dogs treated initially with TFB and in no dogs treated initially with AC (P = .007). Median long-term outcome scores were good in both groups; nine of 14 revision surgeries led to favorable outcomes. CONCLUSION: Persistent shunting requiring revision surgery was more common when CPSS were treated with TFB than with an AC, but both treatments achieved favorable long-term outcomes. CLINICAL SIGNIFICANCE: Treatment of CPPS by placement of an AC rather than TFB seems more reliable for shunt attenuation and prevention of revision surgeries.

The chemical and ultra-structural analysis of thin plastic films used for surgical attenuation of portosystemic shunts in dogs and cats.

The objective of the study was to (1) characterize and compare the chemical composition at the surface, subsurface and in the bulk of thin plastic films used for portosystemic shunt attenuation in their native state and after plasma exposure. (2) Assess the presence, concentration and location of irritant compounds (e.g dicetyl phosphate) within the films. Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), X-ray Photoelectron Spectroscopy (XPS) and dynamic Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) were used to analyze thirteen thin plastic films. Sample thickness was visualized and measured using Scanning Electron Microscopy (SEM). Sample thicknesses were compared using a one-way ANOVA. XPS reported low phosphorous concentrations (surrogate marker of dicetyl phosphate) between 0.01 and 0.19% wt at the sample surfaces (top 10 nm). There were significant differences between film thicknesses (P < .001) observed by SEM. The ATR-IR and ToF-SIMS identified four distinct surface and bulk chemical profiles: 1) Cellophane, 2) Polypropylene, 3) Modified Cellophane, and 4) Unique. Following plasma immersion for 6 weeks, samples showed little change in film thickness or chemical composition. This study confirmed that films used to attenuate portosystemic shunts were commonly not pure cellophane, with significant variations in surface and bulk chemistry. Suspected irritant compounds were not readily identifiable in significant proportions. Pronounced variability existed in both the thickness and chemical composition of these films (surface vs. bulk). The present findings lead to a legitimate question about the reproducibility of shunt occlusion when using thin plastic films from different origins.

Changes in chemical and ultrastructural composition of ameroid constrictors following in vitro expansion.

OBJECTIVE: To (1) characterise the chemical and ultra-structural composition of ameroid constrictors, at a native state and during in vitro expansion and (2) determine the presence of irritant compounds at the surface or within the bulk of the constrictor. METHODS: Twelve sterile, commercially packaged ameroid constrictors (3 repeats of 3.5 mm, 5 mm, 6 mm and 7 mm internal diameter) were analysed by time-of-flight secondary ion mass spectrometry, Raman spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy and scanning electron microscopy. RESULTS: Ameroid constrictors have a composition commensurate with casein with little-to-no intra- or inter- constrictor variation. Microscopic analysis indicated that the topographical features of the constrictor surfaces were consistent between all constrictors. Following in vitro expansion there was a reproducible decrease in Ca+ ion content, little-to-no variation in secondary protein structure and morphological changes including the presence of surface aggregates present only at the inner surface of the ameroid constrictor. The potential irritant polydimethylsiloxane was found on the constrictor surface. A trace quantity of an ion fragment assigned as formaldehyde was detected; however, the extremely low level is thought highly unlikely to play a role as an inflammatory trigger clinically. DISCUSSION: There is a high degree of inter- and intra-constrictor homogeneity from different batches, and reproducible ultrastructural changes following in vitro expansion. Variations occur in both the surface chemistry and topography of the device during closure, which can potentially affect the biomaterial-host interface. Ameroid constrictor closure mechanism is likely involving calcium-mediated inter-protein interactions rather than the imbibition of water only.

Electrosurgery reduces blood loss and immediate postoperative inflammation compared to cold instruments for midline celiotomy in dogs: A randomized controlled trial.

OBJECTIVES: To compare the use of an electrosurgical device with traditional cold instruments (scalpel and scissors) for midline celiotomy incision. STUDY DESIGN: Prospective randomized controlled clinical trial. SAMPLE POPULATION: One hundred and twenty client-owned dogs undergoing abdominal surgery. METHODS: Dogs were prospectively recruited and randomized to receive electroincision or cold instrument incision. For cold incision, surgeons used basic surgical instruments including scalpel and scissors. For electroincision, surgeons only used the electrosurgical device in cutting mode. Time for the approach, blood loss, and the incision length were recorded. A blinded observer assessed pain and incision redness, swelling, and discharge at 24 and 48 hours postoperative (graded 0-3). Owner assessment of incision healing was recorded by telephone interview. RESULTS: Blood loss during surgery was significantly lower for electroincision (mean 0.7, SD 1.7 mL) than cold incision (mean 3.0, SD 4.3 mL, P < .0001) with no significant difference in incision length or time for approach. Electroincision was associated with significantly less incision redness (cold median 1, range 0-3; electroincision median 0, range 0-2, P = .02) and less incision discharge (cold median 0.5 range 0-3; electroincision median 0, range 0-1, P = .006) at 24 hours postoperative. There was no significant difference in pain scores or incision healing in dogs receiving the two techniques. No incisional hernias were reported. A surgical site infection occurred in 1 dog (cold incision). CONCLUSIONS: Electroincision for a celiotomy approach in the dog reduces blood loss, and incision redness and discharge in the immediate postoperative period without affecting the occurrence of wound complications such as infection and dehiscence (including linea alba).

Heterogeneity of T-Tubules in Pig Hearts.

BACKGROUND: T-tubules are invaginations of the sarcolemma that play a key role in excitation-contraction coupling in mammalian cardiac myocytes. Although t-tubules were generally considered to be effectively absent in atrial myocytes, recent studies on atrial cells from larger mammals suggest that t-tubules may be more numerous than previously supposed. However, the degree of heterogeneity between cardiomyocytes in the extent of the t-tubule network remains unclear. The aim of the present study was to investigate the t-tubule network of pig atrial myocytes in comparison with ventricular tissue. METHODS: Cardiac tissue was obtained from young female Landrace White pigs (45-75 kg, 5-6 months old). Cardiomyocytes were isolated by arterial perfusion with a collagenase-containing solution. Ca2+ transients were examined in field-stimulated isolated cells loaded with fluo-4-AM. Membranes of isolated cells were visualized using di-8-ANEPPS. T-tubules were visualized in fixed-frozen tissue sections stained with Alexa-Fluor 488-conjugated WGA. Binary images were obtained by application of a threshold and t-tubule density (TTD) calculated. A distance mapping approach was used to calculate half-distance to nearest t-tubule (HDTT). RESULTS & CONCLUSION: The spatio-temporal properties of the Ca2+ transient appeared to be consistent with the absence of functional t-tubules in isolated atrial myocytes. However, t-tubules could be identified in a sub-population of atrial cells in frozen sections. While all ventricular myocytes had TTD >3% (mean TTD = 6.94±0.395%, n = 24), this was true of just 5/22 atrial cells. Mean atrial TTD (2.35±0.457%, n = 22) was lower than ventricular TTD (P<0.0001). TTD correlated with cell-width (r = 0.7756, n = 46, P<0.0001). HDTT was significantly greater in the atrial cells with TTD ≤3% (2.29±0.16 µm, n = 17) than in either ventricular cells (1.33±0.05 µm, n = 24, P<0.0001) or in atrial cells with TTD >3% (1.65±0.06 µm, n = 5, P<0.05). These data demonstrate considerable heterogeneity between pig cardiomyocytes in the extent of t-tubule network, which correlated with cell size.

Effect of marbofloxacin on cardiovascular variables in healthy isoflurane-anesthetized dogs.

OBJECTIVE: To study the hemodynamic effects of marbofloxacin (MBF) in isoflurane-anesthetized dogs. ANIMALS: 6 healthy 8-month-old Beagles. PROCEDURE: Anesthesia was induced with sodium thiopental and maintained with isoflurane. Cardiovascular variables were monitored throughout anesthesia. Marbofloxacin was administered by an IV bolus at 2 mg/kg, followed 10 minutes later by an infusion at a rate of 40 mg/kg/h for 30 minutes (total dose, 20 mg/kg). Plasma MBF concentrations were measured by high-performance liquid chromatography. RESULTS: The mean peak concentration during MBF infusion was 34.2 +/- 6.4 microg/mL. The IV administration of the MBF bolus did not alter any cardiovascular variable in isoflurane-anesthetized dogs. Significant changes were found during infusion when a cumulative dose of 12 mg/kg had been given. The maximal decreases observed at the end of the infusion were 16% in heart rate, 26% in systolic left ventricular pressure, 33% in systolic aortic pressure, 38% in diastolic aortic pressure, 29% in cardiac output, and 12% in QT interval. All dogs recovered rapidly from anesthesia at the end of the experiment. CONCLUSIONS AND CLINICAL RELEVANCE: MBF may safely be used at 2 mg/kg IV in isoflurane-anesthetized dogs, and significant adverse cardiovascular effects are found only when 6 to 8 times the recommended dose is given.