The utility of the respiratory rate-oxygenation index as a predictor of treatment response in dogs receiving high-flow nasal cannula oxygen therapy.

Objective: This study aims to evaluate the respiratory rate-oxygenation index (ROX) and the ratio of pulse oximetry saturation (SpO2) to the fraction of inspired oxygen (FiO2) (SpO2/FiO2, [SF]) to determine whether these indices are predictive of outcome in dogs receiving high-flow nasal cannula oxygen therapy (HFNOT). Design: This is a prospective observational study. Setting: This study was carried out at two university teaching hospitals. Animals: In total, 88 dogs treated with HFNOT for hypoxemic respiratory failure due to various pulmonary diseases were selected. Measurements and main results: The ROX index was defined as the SF divided by the respiratory rate (RR). ROX and SF were calculated at baseline and for each hour of HFNOT. The overall success rate of HFNOT was 38% (N = 33/88). Variables predicting HFNOT success were determined using logistic regression, and the predictive power of each variable was assessed using the area under the receiver operating curve (AUC). ROX and SF were adequately predictive of HFNOT success when averaged over 0-16 h of treatment, with similar AUCs of 0.72 (95% confidence interval [CI] 0.60-0.83) and 0.77 (95% CI 0.66-0.87), respectively (p < 0.05). SF showed acceptable discriminatory power in predicting HFNOT outcome at 7 h, with an AUC of 0.77 (95% CI 0.61-0.93, p = 0.013), and the optimal cutoff for predicting HFNC failure at 7 h was SF ≤ 191 (sensitivity 83% and specificity 76%). Conclusion: These indices were easily obtained in dogs undergoing HFNOT. The results suggest that ROX and SF may have clinical utility in predicting the outcomes of dogs on HFNOT. Future studies are warranted to confirm these findings in a larger number of dogs in specific disease populations.

Retrospective evaluation of the respiratory rate-oxygenation index to predict the outcome of high-flow nasal cannula oxygen therapy in dogs (2018-2021): 81 cases.

OBJECTIVE: To evaluate the respiratory rate-oxygenation index (ROX), modified ROX index (ROX-HR), and the ratio of pulse oximetry saturation (Spo2) to Fio2 (SF) to determine if these indices over time are predictive of outcome in dogs treated with high-flow nasal cannula oxygen therapy (HFNC). DESIGN: Retrospective study. SETTING: Two university teaching hospitals. ANIMALS: Eighty-one client-owned dogs treated with HFNC for hypoxemic respiratory failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The ROX was defined as the SF divided by the respiratory rate (RR), and the ROX-HR was defined as the ROX divided by the heart rate multiplied by 100. The overall success rate of HFNC was 44% (n = 36/81). Dogs weaned from HFNC had a significantly higher ROX (P < 0.0001) at 1-3, 5-10, 12, and 15 hours than dogs that failed HFNC. Both the ROX and SF showed excellent discriminatory power in predicting HFNC failure at 6 hours, with an area under receiver operating curve of 0.85 (95% confidence interval: 0.72-0.99; P < 0.002) and 0.86 (95% confidence interval: 0.73-0.99; P < 0.001), respectively. The optimal cutoff values for predicting HFNC failure at 6 hours were a ROX ≤3.68 (sensitivity 72%, specificity 92%) and an SF ≤143 (sensitivity 79%, specificity 93%). CONCLUSIONS: These results suggest that similar to people, the ROX and SF are useful predictors of HFNC failure. These indices are easy to measure at the bedside and may have clinical use. Future prospective studies are warranted to confirm the findings and to optimize cutoff values in a larger population of dogs undergoing HFNC.

Successful hemodialysis treatment of a Quarter Horse mare with silver maple leaf toxicity and acute kidney injury.

An adult American Quarter Horse mare presented for pigmenturia and lethargy of 12 hours' duration and was diagnosed with silver maple leaf toxicity. The mare had intravascular hemolysis and azotemia. The mare was treated with a transfusion of whole blood, fluids administered IV, antibiotics, oxygen insufflation, and supportive care. The azotemia persisted despite conventional medical management and hemodialysis was elected. After 2 intermittent hemodialysis treatments over 3 days, the azotemia almost resolved, clinical signs improved, and the mare was discharged. The blood urea nitrogen, creatinine, and electrolyte concentrations remained normal 6 months later after examination by the referring veterinarian. Hemodialysis treatment can be feasible in horses if equipment and expertise are available and should be considered as a treatment option if indicated.

Successful treatment of a severe 5-hydroxytrytophan intoxication using carbon hemoperfusion, hemodiafiltration, and mechanical ventilation in a dog.

OBJECTIVE: To describe the successful use of carbon hemoperfusion and hemodiafiltration in combination with mechanical ventilation (MV) to treat a severe intoxication of 5-hydroxytryptophan (5-HTP) in a dog. CASE SUMMARY: A dog ingested a minimum of 550 mg/kg of extended-release 5-HTP, resulting in serotonin syndrome that progressed to a comatose state and severe hypoventilation requiring MV. Extracorporeal carbon hemoperfusion coupled with hemodiafiltration was performed to remove 5-HTP from this patient. A carbon hemoperfusion cartridge was placed in series upstream in the extracorporeal circuit from the hemodialyzer. A total of 46.5 L of blood (4.89 L/kg) was processed during a 4.85-hour treatment. Serial plasma samples were obtained at 0, 60, 90, and 150 minutes during the session and 14 hours after the session. These samples were later analyzed for 5-HTP and serotonin concentrations. The extraction ratio of 5-HTP was 93.6%-98.9% through the carbon filter. The dog was weaned from MV within 8 hours after extracorporeal therapy and, after a full recovery, was successfully discharged. NEW OR UNIQUE INFORMATION PROVIDED: Despite an extensive review of the available literature, this appears to be the first reported case of using a carbon hemoperfusion, hemodiafiltration, and MV to treat severe serotonin syndrome secondary to 5-HTP intoxication in a dog. The combination of carbon hemoperfusion and hemodiafiltration can significantly reduce plasma 5-HTP concentrations after acute intoxication and may serve to decrease morbidity and mortality in patients with severe intoxication.

Gastrointestinal colonization by Diutina (Candida) rugosa in a 6-year-old Siberian Husky.

A 6-year-old 21.5 kg castrated male Siberian Husky was presented for acute onset of lethargy, vomiting, hemorrhagic diarrhea, and inappetence. Physical examination revealed marked discomfort upon abdominal palpation and 5%-7% dehydration. The CBC and biochemical profile revealed changes consistent with mild to moderate inflammation, dehydration, and gastrointestinal (GI) disease. Despite aggressive gastrointestinal support, anorexia persisted, and an upper GI endoscopy was performed in conjunction with esophagostomy tube placement. Endoscopy revealed abnormal gastric mucosa characterized by moderately well-demarcated areas of blue-black discoloration. Impression smears of a gastric biopsy revealed abundant extracellular yeasts with morphology most consistent with Candida spp. and frequent extracellular cocci. Similar yeast and bacteria, in lower numbers, were observed on cytologic analysis of a direct smear of the rectal mucosa. A rectal swab submitted for fungal culture yielded pure growth of fungal yeasts identified as Diutina (formerly Candida) rugosa by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry. The dog's clinical signs improved with fluconazole, and he was discharged. Follow-up fungal culture of a rectal swab showed no growth of D. rugosa. To the authors' knowledge, this is the first case report that describes the clinical, hematologic, cytologic, and gross findings of enteric colonization by D. rugosa in a dog.

Efficacy of therapeutic plasma exchange in a case of severe, generalised canine pemphigus foliaceus.

Successful treatment of pemphigus foliaceus (PF) often requires a multimodal therapeutic approach. The dog described herein underwent four therapeutic plasma exchange treatments for severe, refractory PF, resulting in a 50% reduction of lesional body surface area. This treatment option should be considered for the management of canine PF.

O tratamento bem-sucedido do pênfigo foliáceo (PF) geralmente requer uma abordagem terapêutica multimodal. O cão aqui descrito foi submetido a quatro tratamentos de troca de plasma terapêutica (TPE) para PF grave e refratário, resultando em uma redução de 50% da área corpórea lesional. Esta opção de tratamento deve ser considerada para o manejo do PF canino.

El tratamiento exitoso del pénfigo foliáceo (PF) a menudo requiere un enfoque terapéutico multimodal. El perro aquí descrito se sometió a cuatro tratamientos terapéuticos de intercambio plasmático (TPE) para un PF refractario grave, lo que resultó en una reducción del 50% de la superficie corporal lesionada. Esta opción de tratamiento debe considerarse para el control de PF canino.

Traiter efficacement le pemphigus foliacé (PF) nécessite souvent une approche thérapeutique multimodale. Dans ce rapport clinique, un chie a reçu quatre traitements de plasmaphérèse thérapeutique (EPT) pour le traitement d'un PF sévère et réfractaire, ce qui a permis de réduire de 50 % la surface corporelle lésionnelle. Cette option thérapeutique devrait être envisagée pour la prise en charge du PF canin.

Use of high-flow oxygen therapy in a cat with cardiogenic pulmonary edema.

Case summary: A 7-month-old female spayed domestic shorthair cat was presented for respiratory distress due to cardiogenic pulmonary edema. Despite initial treatment and oxygen delivery in an oxygen tent, the cat still showed signs of severe respiratory effort and oxygen saturation measured via pulse oximetry was below 85%. Because the owners declined mechanical ventilation, the cat was transitioned to high-flow oxygen therapy (HFOT). HFOT allowed significant improvement of the respiration parameters within 15 mins without causing clinical complications. The cat was briefly anaesthetised for the placement of the nasal cannula on initiation of HFOT, and the interface was well tolerated thereafter. The cat was transitioned to an oxygen cage after 16 h, weaned from oxygen 4 h later and was discharged after 3 days of hospitalisation. Long-term follow-up showed no abnormalities, and the leading hypothesis was transient myocardial thickening. Relevance and novel information: The first use of HFOT in a dyspneic cat is described in this study. HFOT could be a life-saving option for cats with severe hypoxemia or do-not-intubate orders that fail to respond to conventional oxygen therapies.

Infrared thermography is a novel tool to assess small intestinal surface temperature in dogs undergoing laparotomy for foreign body obstruction.

OBJECTIVE: To evaluate local temperature differences directly over and adjacent to small intestinal foreign body obstruction (FBO) using infrared thermography (IRT) in dogs. ANIMALS: 49 client-owned dogs were initially enrolled. METHODS: In a prospective, clinical observational study, IRT was utilized to compare median small intestinal (SI) surface temperature differences at the site of FBO and segments oral and aboral before and after surgical resolution from April 24, 2019, to July 19, 2020. These differences were evaluated for correlation with canine acute patient physiologic and laboratory evaluation fast (APPLEfast) scoring, lactate, foreign body material (hard vs soft), and blood pressure. RESULTS: There was not a significant surface temperature difference between SI segments at the site of FBO, oral or aboral. After resolution of obstruction, there was a significant decrease in median temperature directly over the FBO (2.4 °C; IQR, -2.55 to 10.6 °C; P = .0043). A decrease in surface temperature of the oral SI segment was appreciated with FBO due to hard material (-1.7 °C; IQR, -5.2 to 3.4 °C), whereas soft material had an increase in SI surface temperature oral to the FBO (+1.1 °C; IQR, 0.3 to 3.2 °C). This difference did not achieve significance (P = .08; Z = 1.75). No correlation was found between APPLEfast, lactate, or blood pressure and SI segment temperatures. CLINICAL RELEVANCE: IRT may be useful diagnostic modality to identify changes in small intestinal surface temperature relating to FBO. Further evaluation is warranted to determine if IRT may be a clinically useful to evaluate intestinal perfusion.

Retrospective evaluation of the relationship between admission variables and brain herniation in dogs (2010-2019): 54 cases.

OBJECTIVE: To document the admission systolic blood pressure (SBP), heart rate (HR), and modified Glasgow coma scale (MGCS) score in dogs with and without brain herniation and to determine their relationship with brain herniation. DESIGN: Retrospective study between 2010 and 2019. SETTING: University veterinary teaching hospital. ANIMALS: Fifty-four client-owned dogs with brain herniation and 40 client-owned dogs as a control group, as determined on magnetic resonance imaging. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: SBP, HR, MGCS score, and outcome were extracted from medical records. MGCS score was retrospectively calculated based on initial neurological examination in dogs with adequate available information. Dogs with brain herniation had a significantly higher SBP (P = 0.0078), greater SBP-HR difference (P = 0.0006), and lower MGCS score (P < 0.0001) compared to control dogs. A cutoff value of an SBP ≥ 178 mm Hg, SBP-HR ≥ 60, and MGCS score ≤ 14 each provides a specificity of 90%-98%. A combination of an SBP > 140 mm Hg and HR < 80/min provided 24% sensitivity and 100% specificity to diagnose dogs with brain herniation (P < 0.0001). CONCLUSIONS: A high SBP, a greater difference between SBP and HR, a combination of higher SBP and lower HR, and a low MGCS score were associated with brain herniation in dogs presenting with neurological signs upon admission. Early recognition of these abnormalities may help veterinarians to suspect brain herniation and determine timely treatment.

Relationship between admission vitals and brain herniation in 32 cats: a retrospective study.

OBJECTIVES: The aim of the study was to evaluate whether any admission vitals correlated with the presence of brain herniation diagnosed via MRI in cats presenting with neurologic signs. METHODS: Medical records at two veterinary university referral centers were reviewed to identify cats that underwent brain MRI between 2010 and 2019. A control group of cats with intracranial lesions without concurrent brain herniation was analyzed for comparison. Data relating to signalment, vitals on admission, abnormalities observed on initial neurologic examination, underlying etiology, advanced imaging findings and outcome were reviewed. A Modified Glasgow Coma Scale (MGCS) score was determined retrospectively based on initial neurologic examination. Logistic regressions were performed to investigate the relationship between each risk factor and the odds of brain herniation as diagnosed on MRI. RESULTS: Thirty-two cats with brain herniation and 44 cats with abnormal brain MRI without evidence of herniation (as a control group) based on MRI findings were included. Cats with intracranial neoplasia vs other diagnoses were found to be at increased risk of herniation (odds ratio [OR] 4.8, 95% confidence interval [CI] 1.8-13.8; P = 0.001). The odds of herniation increased with age (OR 1.1, 95% CI 1.01-1.2; P = 0.031). Cats with herniation had a significantly lower level of consciousness in their MGCS score (P <0.0001) than cats without herniation. There was no significant difference in either motor activity or brainstem reflexes between the groups (P >0.05). CONCLUSIONS AND RELEVANCE: Admission heart rate and blood pressure were not associated with brain herniation. Cats with herniation were presented with a significantly lower level of consciousness in their MGCS score; however, this clinical feature cannot be directly attributable to and predictive of herniation. Older cats with intracranial neoplasia are more likely to have brain herniation.

Pharmacokinetics of Pimobendan and Its Metabolite O-Desmethyl-Pimobendan Following Rectal Administration to Healthy Dogs.

Objective: This study describes the pharmacokinetics of parent pimobendan (PIM) and its active metabolite, o-desmethyl-pimobendan (ODMP), after oral and rectal administration of pimobendan to healthy dogs. Animals: A total of eight healthy privately owned dogs were used in this study. Procedures: The dogs received a single dose (0.5 mg/kg) of a commercially available pimobendan tablet per os (PO). Twelve blood samples were collected over a 12-h period for pharmacokinetic analysis. After a 24-h washout period, the dogs received the same dose of pimobendan solution per rectum (PR), and samples were obtained at the same time for analysis. Results: For PIM, PO vs. PR, respectively, the mean maximum plasma concentration (C max, ng/ml) was 49.1 ± 28.7 vs. 10.1 ± 2, the time to reach a maximum concentration (T max, h) was 2.1 ± 0.9 vs. 1 ± 0.4, the disappearance half-life (t 1/2, h) was 1.8 ± 0.8 vs. 2.2 ± 0.6, and the area under the concentration-time curve (AUC, ng*h/ml) was 148.4 ± 71.6 vs. 31.1 ± 11.9, with relative bioavailability (F, %) of 25 ± 8. For ODMP, PO vs. PR, respectively, C max was 30.9 ± 10.4 vs. 8.8 ± 4.8, T max was 3.2 ± 1.6 vs. 1.7 ± 1.1, and t 1/2 was 5.0 ± 2.7 vs. 8.3 ± 4.8, with AUC of 167.8 ± 36.2 vs. 50.1 ± 19.2 and F of 28 ± 6. The differences between PO and PR were significant (P < 0.03) for AUC and C max for both PIM and ODMP. Conclusions and Clinical Relevance: The pharmacokinetics of PIM and ODMP were described following PO and PR administration. The findings suggest that pimobendan PR might achieve effective concentrations and, as such, warrant future studies of clinical effectiveness in treating dogs with congestive heart failure and which are unable to receive medication PO.