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Alpacas (Vicugna pacos) have physiologic adaptations to live at high altitude. These adaptations may result in unexpected responses to changes in cardiac performance and blood pressure during general anesthesia. There are few studies evaluating cardiovascular variables in anesthetized alpacas. The purpose of this study was to report cardiovascular performance in anesthetized mature alpacas during normotension, hypotension, and hypertension using ultrasound dilution and echocardiography. Six adult alpacas, 3 females and 3 castrated males, weighing 62.6 to 88.7 kg were anesthetized and maintained with isoflurane and placed in right lateral recumbency. Each alpaca underwent ultrasound dilution and echocardiography measurements during three cardiovascular phases, normotension, hypotension via increased isoflurane concentration, and hypertension via phenylephrine infusion. Variables were analyzed with a Friedman test and a post hoc Dunn’s test when significant. A p < 0.05 was used for significance. Cardiac output, cardiac index, systemic vascular resistance, stroke volume, total ejection fraction, left ventricular internal diameter during diastole, and total stroke volume indexed to body weight were greater for hypertension compared to hypotension. Total ejection fraction, stroke volume, and left ventricular ejection time were greater for hypertions compared to normotension. There was no difference between ultrasound dilution and echocardiography determined cardiac output measurements within each cardiovascular phase. Phenylephrine appeared to have increased ventricular performance and/or increased preload in anesthetized, mature alpacas. For detecting change in cardiovascular status in anesthetized alpacas, ultrasound dilution and echocardiography may be useful.

Brachycephalic obstructive airway syndrome (BOAS) is associated with significant morbidity and mortality. Routine clinical evaluation fails to detect physiologic consequences of BOAS including airflow limitation, exercise intolerance, and impaired thermoregulation. A six-minute walk test (6MWT) with infrared thermography (IRT) may aid detection and clinical management by assessing the physiologic consequences of BOAS. IRT has been used in dogs to assess thermoregulation and in people with obstructive sleep apnea. Our objectives were to compare 6MWT and IRT parameters between healthy mesaticephalic (Mesa) and brachycephalic (Brachy) dogs, and dogs with BOAS. 6MWT parameters include normalized distance walked (ND), rectal temperature, pulse, respiratory rate, and pulse oximetry (SPO2). Mean (Tmean) and maximum (Tmax) IRT temperatures at 3 regions of interest (ROI) were evaluated. Evaluation timepoints were pre-6MWT, immediately post-6MWT (T0) and 5 (T5) and 15min post-6MWT (T15). No significant difference in ND, SPO2, or temperature were found between groups (p>.05). BOAS dogs had higher dorsal and rostral Tmax and Tmean temperatures compared to Mesa dogs at all timepoints (p < .05). BOAS dogs had higher Tmean temperatures compared to Brachy dogs at baseline and T15 and T5 and T15 for dorsal and rostral ROIs respectively (p < .001). ROC analysis showed significant discrimination between BOAS and non-BOAS (Brachy and Mesa) dogs with areas under the curve between 0.79-0.96. Significant moderate correlations were found between IRT temperatures, ND and rectal temperature. This pilot study demonstrates the potential in pairing the 6MWT and IRT with evaluation of clinical signs as screening tool to identify dogs with BOAS.

Infrared thermography detects variations in heat signature and is utilized in other species to non-invasively identify respiratory disease. This study aimed to determine if infrared thermography could be used to detect nasal disease in dogs. Eight dogs presenting for nasal disease (ND group) and ten healthy control dogs (C group) were enrolled. Dorsal and rostral images of the nose were acquired using a Fluke TiX580 60Hz thermal imaging camera. Images were analyzed using the accompanying software. Regions of interest were defined over the right and left nasal passages to determine the maximum (max), average (avg), and minimum (min) temperatures. Temperatures were compared between ND and C groups, and correlation to disease state (ND or C) was evaluated. Temperature differences and imaging patterns were subjectively compared with diagnosis based on computed tomography (CT) and histopathology. The ND group consisted of 5 spayed females and 3 neutered males. Clinical sings included unilateral epistaxis (n = 4); bilateral serous discharge and sneezing (n = 1); bilateral mucopurulent discharge, epistaxis, and sneezing (n = 1); unilateral mucoid discharge, epistaxis and sneezing (n = 1); and sneezing and unilateral epistaxis (n = 1). Temperatures were significantly different between ND and C groups on dorsal (max p =