Influence of changing lateral recumbency and mode of ventilation on the alveolar-arterial oxygen tension gradient and selected laboratory analytes in adult isoflurane anesthetized horses.

This study investigated the influence of changing recumbency and mode of ventilation over repeated anesthesias on the alveolar to arterial oxygen tension gradient (PA-aO2) and laboratory analytes in eight horses during a year-long imaging study. Anesthesia was induced with xylazine, diazepam or guaifenesin, and ketamine and maintained with isoflurane. Horses were positioned in right or left lateral recumbency for computed tomography. Ventilation was controlled during 47% of the anesthetics. Blood was sampled from an arterial catheter prior to (30 ± 5 min from connection to anesthetic circuit), within 5 min of changing lateral recumbency, and prior to circuit disconnection (24 ± 6 min after second sample) for measurement of pH, partial pressure of arterial oxygen (PaO2) and partial pressure of arterial carbon dioxide, blood glucose and electrolytes. PA-aO2 was calculated. Data from five anesthetic episodes for each horse were summarized as mean ± standard error and analyzed using a mixed-model ANOVA. t tests were used for pairwise comparisons (P<0.05). PaO2 decreased after turning (198 vs. 347 mmHg), then increased to 291 mmHg prior to disconnection. Correspondingly, PA-aO2 was wider (252 vs.120 mmHg), and improved before disconnection (190 mmHg). Body temperature, ionized-Ca2+ and blood glucose were lower, and Na+ was higher at the last time point. In conclusion, turning anesthetized horses decreases PaO2 and results in a widening PA-aO2 suggesting a cautious approach in animals with pre-existing hypoxemia.

Relationship between repository radiographic findings and subsequent performance of Quarter Horses competing in cutting events.

OBJECTIVE To investigate potential associations between repository radiographic findings and subsequent performance of Quarter Horses competing in cutting events. DESIGN Retrospective cohort study. SAMPLE Repository radiographs (ie, radiographs obtained at the time of sale) for 343 client-owned horses. PROCEDURES Repository radiographic findings were compared with objective measures of performance, including the likelihood of competing; the likelihood of earning money as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined; and the amount of money earned as a 3-year-old, as a 4-year-old, and as a 3- and 4-year-old combined. RESULTS The presence of mild osteophytes involving the distal aspect of the tarsal joint was significantly associated with lower mean earnings as a 4-year-old. The presence of osteophytes on the dorsoproximal aspect of the middle phalanx of the hind limbs was significantly associated with an increased odds of earning money as a 4-year-old. Radiographic lesions of the medial femoral condyle of the stifle joint were not significantly associated with subsequent performance. CONCLUSIONS AND CLINICAL RELEVANCE Most abnormalities identified on repository radiographs were not significantly associated with subsequent performance. The significant association between mild tarsal osteophytosis and earnings was unexpected. Results of the present study indicated the need for further investigation of the relationship between radiographic findings and performance outcome in Western performance horses.

Effects of high doses of enalapril and benazepril on the pharmacologically activated renin-angiotensin-aldosterone system in clinically normal dogs.

OBJECTIVE: To determine whether high doses of enalapril and benazepril would be more effective than standard doses of these drugs in suppressing the furosemide-activated renin-angiotensin-aldosterone system (RAAS). ANIMALS: 6 healthy Beagles. PROCEDURES: 2 experiments were conducted; each lasted 10 days, separated by a 2-week washout period. In experiment 1, all dogs received furosemide (2 mg/kg, PO, q 12 h) and enalapril (1 mg/kg, PO, q 12 h) for 8 days (days 0 through 7). In experiment 2, dogs received furosemide (2 mg/kg, PO, q 12 h) and benazepril (1 mg/kg, PO, q 12 h) for 8 days. Effects on the RAAS were determined by assessing serum angiotensin-converting enzyme (ACE) activity on days -1, 3, and 7; serum aldosterone concentration on days -2, -1, 1, 3, and 7; and the urinary aldosterone-creatinine ratio (UAldo:C) in urine collected in the morning and evening of days -2, -1, 1, 3, and 7. RESULTS: High doses of enalapril and benazepril caused significant reductions in serum ACE activity on all days but were not more effective than standard doses used in other studies. Mean UAldo:C remained significantly higher on days 2 through 7, compared with baseline values. Serum aldosterone concentration also increased after drug administration, which mirrored changes in the UAldo:C. CONCLUSIONS AND CLINICAL RELEVANCE: In this study, administration of high doses of enalapril and benazepril significantly inhibited ACE activity, yet did not prevent increases in mean urine and serum aldosterone concentrations resulting from furosemide activation of RAAS. This suggested that aldosterone breakthrough from ACE inhibition was a dose-independent effect of ACE inhibitors.

Investigating the use of written and performance-based testing to summarize competence on the case management component of the NBCE part IV-national practical examination.

BACKGROUND: Large-scale performance-based examinations are logistically complex and costly to run. Scores based solely on performance-based stations require extended testing time to achieve acceptable generalizability. PURPOSE: Combining scores from performance-based formats and written formats may improve test generalizability. METHODS: Data from 718 test-takers on the standardized patient-based portion of the National Board of Chiropractic Examiners Part IV examination were analyzed using a generalizability framework. RESULTS: The written and performance scores displayed a moderate universe score correlation indicating each component provided unique information about related clinical skills and the examinee's ability to manage a case. Combining the two scores provided a summary score that was more generalizable than either of the two measures individually. CONCLUSION: These results provide guidance for improving the generalizability of the standardized patient-based stations by combining the scores on the performance and written components using appropriate weighting procedures.