Climate and human mortality in Virginia, 2005-2020.

Using an extensive database of every resident death in Virginia from 2005 to 2020, climate-mortality relationships are examined for 12 climatically homogeneous regions within the Commonwealth. Each region is represented by a first-order weather station from which archived temperature and humidity data are used to generate a variety of biometeorologically relevant indices. Using these indices and other variables (such as air quality and heat and cold waves), daily mortality and climate relationships are modeled for each region over a 21-day lag period utilizing generalized additive models and distributed lag non-linear models. Optimal models are identified for each region, and a consensus model was also run based on maximum temperature to facilitate inter-regional comparisons. The relative risk of mortality varies markedly as a function of climate between regions, with U-shaped, J-shaped, and inverse linear relationships evident. Cold mortality exceeds heat mortality across most of Virginia (typical relative risks are 1.10 for cold and 1.03 for heat), with cold risks strongest at lags 3 to 10. Low temperatures (or low humidity) are protective at lags 0-2 days except in the colder, western parts of state. Heat mortality occurs at short lags (0-2 days) for three-fourths of the stations, but the spatial pattern is random. Mortality displacement is evident for most regions for several days following the heat-related spike. Although the use of region-specific models is justified, the simple consensus model based on a consistent set of predictors provides similar results.

Anatomical localisation of the maxillary nerve with the use of computed tomography to aid nerve block placement in dogs.

BACKGROUND: The maxillary block is a commonly used anaesthetic technique in dogs; however, no universal recommendations for the best method to perform this block exist. Differences between using this block in brachycephalic and non-brachycephalic breeds have not been examined. This study compared the position of the maxillary nerve using CT in brachycephalic and non-brachycephalic dogs. METHODS: Forty CT images of the heads of dogs of varying conformation were analysed. The distances and angles to the maxillary nerve from the injection site within the oral cavity were measured. If present in the same plane, the distance to the eye was measured. Measurements of jaw width and length were taken to ascertain if they correlated to the distance to the maxillary nerve from the oral cavity. RESULTS: There was no difference in angle between brachycephalic and non-brachycephalic dogs; however, the distance between nerve and injection point in brachycephalic dogs was generally greater. A regression equation relating maxillary nerve depth to jaw width was found. The eye was more likely to be in the plane of injection if the dog was non-brachycephalic. CONCLUSION: The discovered relationship between jaw width and maxillary nerve depth may allow more accurate injections to be made.

Description of a novel ultrasound guided peribulbar block in horses: a cadaveric study.

BACKGROUND: Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). OBJECTIVE: To describe a technique for USG PB in horse cadavers. METHODS: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised to two operators naïve to the USG PB, with moderate experience with ultrasonography and conventional "blind" RB. Both techniques were demonstrated once. Subsequently, operators performed five USG PB and five RB each, unassisted. Contrast location and spread were evaluated by CT. Injection site success was defined for USG PB as extraconal contrast, and for RB intraconal contrast. RESULTS: Success was 10/10 for USG PB and 0/10 for RB (p < 0.001). Of the RB injections, eight resulted in extraconal contrast and two in the masseter muscle (p = 0.47). CONCLUSIONS: The USG PB had a high injection site success rate compared with the RB technique; however, we cannot comment on clinical effect. The USG technique was easily learnt, and no potential complications were seen. The USG PB nerve block could have a wide application for use in horses for ocular surgeries (enucleations, eyelid, corneal, cataract surgeries, and ocular analgesia) due to reduced risk of iatrogenic damage. Further clinical studies are needed.

Vascular ultrasonographic findings in canine patients with clinically diagnosed phlebitis.

Peripheral vein phlebitis (inflammation) is a relatively frequent complication in dogs, however, published information on the ultrasonographic characteristics is currently lacking. This prospective, observational study describes the ultrasound (US) characteristics of normal canine cephalic veins, and veins with clinical phlebitis. Correlations among US findings and between US findings versus time that the intravenous catheter was in place were investigated. Safety of the US procedure was evaluated. Fifty patients were prospectively recruited for the study and 18 met the final inclusion criteria. Each patient underwent daily US examinations and was assessed for multiple criteria (vascular wall appearance, compressibility, spontaneity of flow, color fill, and presence/absence of filling defects, flow contour, direction, non-pulsatility). Characteristics of normal canine cephalic veins were as follows: smooth and thin wall, complete compressibility, no flow disturbances, no filling defects, smooth flow contours, and unidirectional, non-pulsatile flow with no turbulence. Characteristics of cephalic veins with clinical phlebitis were as follows: wall thickening (83%), decreased compressibility (55%), filling defects consistent with intraluminal thrombus (55%), vessel wall hyperechogenicity (44%), and abnormal color Doppler flow (39%). Significant correlations were found between Doppler filling defects and compressibility, Doppler filling defects and presumed thrombosis, and compressibility and presumed thrombosis (P = .001, P = .001, P = .000, respectively). No correlation was found between the US findings and time the intravenous catheter was in place. Findings indicated that duplex and compressibility US are feasible and safe methods for characterizing and monitoring cephalic veins in dogs with clinical phlebitis.

Postoperative respiratory effects of intravenous fentanyl compared to intravenous methadone in dogs following spinal surgery.

OBJECTIVE: To evaluate the 24-hour postoperative respiratory effects of either intravenous fentanyl administered as a constant rate infusion or boluses of methadone, in dogs following spinal surgery, assessed by serial arterial blood gas analyses. STUDY DESIGN: Prospective, randomized clinical study. ANIMALS: Thirty-two healthy dogs (American Society of Anesthesiologists I/II) anaesthetized for elective caudal thoracic and/or lumbar decompression spinal surgery. METHODS: Dogs were assigned randomly to be administered a fentanyl constant rate infusion (5 µg kg-1 hour-1; group F, n = 14) or methadone boluses (0.2 mg kg-1, every 4 hours; group M, n = 15) postoperatively for 24 hours. Each dog's anaesthesia protocol was customized. Arterial blood samples were collected from an arterial cannula, placed under anaesthesia, at 4, 8, 12 and 24 hours postextubation, while breathing room air. Cardiorespiratory variables, Glasgow composite pain scale (GCPS) and sedation (SED) scores were also recorded at these time points. Independent t tests, repeated measures anova and Mann-Whitney U tests were used. Significance was defined as p < 0.05. RESULTS: There were no significant differences found between groups in any of the overall mean values or at any time point for values of partial pressure of oxygen [13.9 ± 2.1 kPa (103.9 ± 16.1 mmHg) and 12.6 ± 2.0 kPa (94.7 ± 15.2 mmHg)], partial pressure of carbon dioxide [4.8 ± 0.6 kPa (36 ± 4.2 mmHg) and 4.9 ± 0.6 kPa (36.5 ± 4.5 mmHg)], pH (7.38 ± 0.03 and 7.40 ± 0.03), bicarbonate (21.5 ± 2.3 mm and 21.9 ± 6.6 mm) and base excess (-3.4 ± 2.6 mm and -2 ± 3 mm) for groups F and M, respectively. Cardiorespiratory variables, GCPS and SED scores were also similar between groups. CONCLUSIONS AND CLINICAL RELEVANCE: At the doses studied, neither fentanyl nor methadone caused respiratory depression postoperatively in dogs following caudal thoracic and/or lumbar spinal surgery.