Preliminary evaluation of the use of high-flow nasal cannula oxygen therapy during recovery from general anesthesia in dogs with obstructive upper airway breathing.

BACKGROUND: Brachycephalic airway syndrome can pose a risk of complicated recovery from anesthesia as a result of irritation to the excess pharyngeal andlaryngeal tissue present in affected dogs. High-flow nasal cannula (HFNC) oxygen therapy is a respiratory support modality that offers provision of continuous positive airway pressure via high gas flow rates. The HFNC system actively warms and humidifies inspired gases, which improves comfort and facilitates tolerance of the high flow rates in people and dogs. HFNC oxygen therapy was applied to brachycephalic dogs that developed increased work of breathing or hypoxemia in the recovery phase of anesthesia to determine if this device would be tolerable and effective for relief of upper respiratory difficulty. KEY FINDINGS: The HFNC nasal prong interface is well suited to the brachycephalic facial structure. The application of HFNC was found to reduce dyspnea scores in patients with signs of upper airway obstruction after general anesthesia. Aerophagia and changes in PCO2 were noted. SIGNIFICANCE: Application of HFNC in the recovery period may result in improved airflow during times of somnolent obstructive breathing, not unlike the use of continuous positive airway pressure therapy in sleep-disordered breathing in people.

Canaliculorhinostomy as a treatment for nasolacrimal duct obstruction in dogs and cats.

OBJECTIVES: To create a replacement nasolacrimal system, using the puncta and canaliculi, with prolonged implant retention and minimal use of Elizabethan collars or other restraint devices. MATERIALS AND METHODS: The method was used in 11 dogs and two cats. Silicone tubing was placed through both canaliculi and, via a drill hole, into the nasal cavity. Distally, the tubing ends were tied in a subcutaneous pocket lateral to the premaxilla. Tubing retention time was 4 to 7 months. Elizabethan collars were used only until skin suture removal at 2 weeks. RESULTS: In all animals, a functional nasolacrimal system was re-created and remained patent over prolonged follow-up periods. Adverse effects and complications were mild. CLINICAL SIGNIFICANCE: The described method is relatively straightforward, thereby making relief of tear outflow problems widely accessible.

Endotracheal tube placement during computed tomography of brachycephalic dogs alters upper airway dimensional measurements.

Computed tomography (CT) is used to document upper airway lesions in dogs with brachycephalic obstructive airway syndrome. The presence of an endotracheal tube during CT scanning is often required for general anesthesia. We hypothesized that the endotracheal tube placement would change the soft tissue dimensions of the upper airway. The aims of this prospective, method comparison study were to evaluate the reliability of the previously reported upper airway CT measurements with endotracheal tube placement, and to propose measurements that are minimally affected by the endotracheal tube. Twenty brachycephalic dogs were included in this study. Each dog underwent head/neck CT with an endotracheal tube, followed by a second scan without the endotracheal tube. Ten measurements of the soft palate, nasopharynx, and trachea were performed. Tracheal dimension was significantly larger with the endotracheal tube compared to without, whereas the soft palate cross-sectional area was significantly smaller with the endotracheal tube than without the endotracheal tube. The influence of the endotracheal tube on the caudal nasopharynx cross-sectional (transverse-sectional) area varied with a mean proportional absolute difference of 35%. Rostral soft palate thickness, tracheal perimeter, and cross-sectional area of the rostral nasopharynx were the measurements least affected by the endotracheal tube (intraclass correlation coefficient = 0.964, 0.967, and 0.951, respectively). Therefore, we proposed that these three measurements may be most useful for future brachycephalic obstructive airway syndrome studies that require CT scanning of intubated animals. However, with endotracheal tube placement, measurements of soft palate length, caudal nasopharyngeal cross-sectional area, and trachea height and width may not be reliable.

Experimental elevation of wildlife testosterone using silastic tube implants.

Testosterone (T) is a key androgen that mediates vertebrate molecular, cellular, and behavioral processes. Its manipulation is therefore of interest to a vast number of researchers studying animal behavior and reproduction, among others. Here, the usage of silastic implants across wildlife species is reviewed, and a method to manipulate rock hyrax (Procavia capensis) testosterone levels using silastic implants is presented. Using a series of in-vitro and in-vivo experiments, the secretion patterns of silastic tubes and silastic glue were tested and were surprisingly found to be similar. In addition, we studied endogenous T levels in wild-captured rock hyraxes (Procavia capensis), and using T implants succeeded in elevating T to the maximal physiological concentrations recorded during the mating period. The number of implants that were inserted was the only predictor of T levels, and seven 20mm implants were found to be the optimal dose. Implants induced sexual behaviors in the non-reproductive period. The duration of time that the implants were in the hyrax was the only significant factor that influenced the amount of T left over in the implant once it was removed. All together we affirm that T implants may offer a versatile tool for wildlife behavioral research by elevating T levels in the non-breeding period to maximal breeding levels.

Comparative analysis of lung function of rats using a new intubation technique and tracheostomy / Análise comparativa da função pulmonar de ratos usando uma nova técnica de intubação e a traqueostomia

Several studies use intubation or tracheostomy for data collection in lung function of rats. Due to the difficulty of performing intubation, tracheostomy is most commonly used. Knowing this difficulty, this paper demonstrates a new way to perform the intubation technique and compares pulmonary function variables obtained using intubation or tracheostomy. For the analysis of our new technique of intubation, 30 rats were used, and the comparative analysis of lung function data obtained through the use of our technique of intubation and tracheostomy, 16 rats were used, divided into two groups. The T group underwent tracheostomy. The IT group underwent initial intubation and, awaiting recovery, a week later was again subjected to intubation group, which was then called IT-1W. Our intubation technique is performed with the aid of a wedge, inclined bed and percutaneous transillumination. No animals died during the intubation procedure, and about 77% of the animals were intubated at the first attempt. We did not obtain statistically significant differences in the pulmonary function variables between the groups. Our intubation technique is easily learned and reproduced. The implications of such a technique can be generalized to all laboratories dealing with intubation of rats.(AU)

Vários estudos utilizam a intubação orotraqueal ou traqueostomia para coleta de dados na função pulmonar de ratos. Devido à dificuldade de realização da intubação, a traqueostomia é mais comumente utilizada. Conhecendo esta dificuldade, este trabalho demonstra uma nova maneira de realizar a técnica de intubação e compara as variáveis de função pulmonar obtidas por intubação ou traqueostomia. Para a análise de nossa nova técnica de intubação, foram utilizados 30 ratos, e para a análise comparativa dos dados da função pulmonar obtidos pelo uso de nossa técnica de intubação e traqueotomia, 16 ratos foram utilizados, divididos em dois grupos. O grupo T foi submetido a traqueostomia. O grupo de IT foi submetido inicialmente a intubação e, esperada sua recuperação, uma semana depois foi novamente submetido a intubação, que foi então chamado de grupo IT-1W. Nossa técnica de intubação é realizada com a ajuda de uma cunha, cama inclinada e transiluminação percutânea. Nenhum animal morreu durante o procedimento de intubação, e cerca de 77% dos animais foram intubados na primeira tentativa. Não foram obtidas diferenças estatisticamente significativas nas variáveis de função pulmonar entre os grupos. Nossa técnica de intubação é facilmente aprendida e reproduzida. As implicações de tal técnica podem ser generalizadas para todos os laboratórios que lidam com a intubação de ratos.(AU)

Development and Evaluation of Two Canine Low-Fidelity Simulation Models.

Two self-made low-fidelity models for simulation of canine intubation and canine female urinary catheterization were developed and evaluated. We used a study design that compares acquired skills of two intervention groups and one control group in a practical examination. Fifty-eight second-year veterinary medicine students received a theoretical introduction to intubation and were randomly divided into three groups. Group I (high-fidelity) was then trained on a commercially available Intubation Training Manikin (item #2006, Veteffects), group II (low-fidelity) was trained on our low-fidelity model, and group III (text) read a text describing intubation of the dog. Forty-seven fifth-year veterinary medicine students followed the same procedure for training urinary catheterization using the commercially available Female Urinary Catheter Training Manikin (Paws 2 Claws), our self-made model, and text. Outcomes were assessed in a practical examination on a cadaver using an Objective Structured Clinical Examination (OSCE) checklist. Considering a value of p≤.05 significant, intervention groups performed significantly better than the text groups. Group I (high-fidelity) and group II (low-fidelity) showed no significant differences (p≤.684, intubation; p≤.901, urinary catheterization). We thereby conclude that low-fidelity models can be as effective as high-fidelity models for clinical skills training.

Systemic and mucosal immune response of rainbow trout to immunization with an attenuated Flavobacterium psychrophilum vaccine strain by different routes.

Teleosts possess three immunoglobulin (Ig) heavy chain isotypes viz., IgM, IgT and IgD and all three isotypes are reported in rainbow trout. The expression of these Ig isotypes in response to different immunization routes was investigated and results provide a better understanding of the role these Igs in different tissues. Rainbow trout (Oncorhynchus mykiss) were immunized with an attenuated Flavobacterium psychrophilum strain, 259-93-B.17 grown under iron limiting conditions, by intraperitoneal, anal intubation and immersion routes. Serum, gill mucus, skin mucus and intestinal mucus samples were collected at 0, 3, 7, 14, 28, 42 and 56 days post immunization by sacrificing four fish from each treatment group and the unimmunized control group, and the IgM levels were estimated by an enzyme linked immunosorbent assay (ELISA). In addition, blood, gill, skin and intestinal tissue samples were collected for Ig gene expression studies. The secretory IgM, IgD and IgT gene expression levels in these tissues were estimated by reverse transcription quantitative real time PCR (RT-qPCR). Levels of IgM in serum, gill and skin mucus increased significantly by 28 days after immunization in the intraperitoneally immunized group, while no significant increase in IgM level was observed in fish groups immunized by other routes. Secretory IgD and IgT expression levels were significantly upregulated in gills of fish immunized by the immersion route. Similarly, secretory IgT and IgD were upregulated in intestines of fish immunized by anal intubation route. The results confirm mucosal association of IgT and suggest that IgD may also be specialized in mucosal immunity and contribute to immediate protection to the fish at mucosal surfaces.

Management of dogs and cats with endotracheal tube tracheal foreign bodies.

Two cats and 3 dogs were treated for an endotracheal tube tracheal foreign body (ETFB) during recovery from general anesthesia. Bronchoscopy was used to remove the ETFB. Animals were clinically normal at discharge. While rare, ETFB can occur upon recovery from anesthesia. Bronchoscopy is an effective way to remove ETFB.

Gestion des chiens et des chats avec un corps étranger trachéal à cause du tube endotrachéal. Deux chats et 3 chiens ont été traités pour un corps étranger trachéal à cause du tube endotrachéal (CETTT) durant le réveil de l'anesthésie générale. Une bronchoscopie a été utilisée pour enlever le CETTT. Les animaux étaient cliniquement normaux au congé. Quoique rare, le CETTT, peut se produire au réveil de l'anesthésie. La bronchoscopie est une manière efficace d'enlever le CETTT.(Traduit par Isabelle Vallières).

Cardiovascular effects of orotracheal intubation following anesthetic induction with propofol, ketamine-propofol, or ketamine-diazepam in premedicated dogs.

OBJECTIVE: To compare the hemodynamic responses to orotracheal intubation following induction of anesthesia with propofol, ketamine-propofol, and ketamine-diazepam in premedicated dogs. DESIGN: Prospective, randomized, masked study. ANIMALS: 10 healthy adult Beagles. PROCEDURES: Dogs were randomly allocated to be anesthetized twice, with a 1-week wash-out interval, by means of 2 of 3 possible protocols (propofol [4 mg/kg {1.8 mg/lb}, n = 6 dogs], ketamine [2 mg/kg {0.9 mg/lb}] and propofol [2 mg/kg; 7], or ketamine [5 mg/kg {2.3 mg/lb}] and diazepam [0.2 mg/kg {0.09 mg/lb}; 6]). After instrumentation, continuous heart rate, systolic arterial blood pressure, mean arterial blood pressure, diastolic arterial blood pressure, cardiac index, stroke volume index, and systemic vascular resistance were recorded. Fifteen minutes after premedication, dogs were anesthetized; all anesthetics were administered IV. After 5 minutes, orotracheal intubation was performed without the use of a laryngoscope. Data were collected prior to intubation (baseline), at intubation, and 30, 60, 90, 120, 150, and 180 seconds thereafter. Results were compared among the 3 groups and over time. RESULTS: No differences among groups were observed for any variables studied. In all groups, arterial blood pressures were significantly decreased at various time points after intubation. A significant increase in systolic arterial blood pressure was observed between baseline and the 30-second time point in the ketamine-diazepam group. No significant differences were detected over time for the other variables in any group. CONCLUSIONS AND CLINICAL RELEVANCE: Intubation after anesthetic induction with ketamine-diazepam caused transitory hypertension, whereas intubation after induction with propofol or ketamine-propofol did not cause cardiovascular stimulation. In dogs in which hypertension is a concern, propofol or ketamine-propofol may be a better choice for induction prior to orotracheal intubation.

The effects of repeated oral gavage on the health of male CD-1 mice.

Oral gavage is a widely used method for administering substances to animals in pharmacological and toxicological studies. The authors evaluated whether oral gavage causes behavioral indicators of stress, increased mortality rate, alterations in food and water consumption and body weight or histological lesions in CD-1 mice. Gavage was carried out once per d for 5 d per week over 6 consecutive weeks. The mortality rate of mice in this study was 15%. Mice subjected to gavage did not undergo changes in food or water consumption during the study, and their mean body weights and relative organ weights were similar to those of mice in the control group. Serum cortisol levels at the time of euthanasia in mice in both groups were within the normal range. Histopathology showed acute esophagitis and pleurisy, indicative of perforation of the esophagus, in the two mice that died but no abnormalities in the other mice. The results suggest that animal stress and mortality related to oral gavage can be minimized when the procedure is carried out by an experienced technician.

Comparison of the amounts of air leakage into the thoracic cavity associated with four thoracostomy tube placement techniques in canine cadavers.

OBJECTIVE: To compare the amount of air leakage into the thoracic cavity associated with each of 4 thoracostomy tube placement techniques in canine cadavers. SAMPLE POPULATION: 28 canine cadavers. PROCEDURES: Thoracostomy tube placement techniques (7 cadavers/technique) included subcutaneous tunneling with a silicone tube by use of Carmalt forceps or with a polyvinyl chloride tube by use of a trocar (SC-CARM and SC-TRO, respectively) and tunneling under the latissimus dorsi muscle with similar tube-instrument techniques (LD-CARM and LD-TRO, respectively). Differences in intrapleural pressures (IPPs) measured before and after tube placement and before and after tube removal were calculated; duration of air leakage around the tubes was assessed by use of a 3-chamber thoracic drainage system. RESULTS: Tunneling method and depth had no interaction effect on the difference in IPP measured before and after tube placement; the IPP difference for both forceps technique groups was significantly greater than findings for both trocar technique groups. Tunneling method and depth had an interaction effect on the difference in IPP measured before and after tube removal; compared with SC-TRO and LD-CARM group differences, the SC-CARM group difference was significantly greater, but the LD-TRO group difference was similar. More intermittent air leakage was associated with the 2 forceps techniques than with the 2 trocar techniques. CONCLUSIONS AND CLINICAL RELEVANCE: Trocar-implemented thoracostomy tube placement in canine cadavers resulted in less air leakage than the forceps method. Air leakage upon tube removal was less pronounced for the LD-CARM technique than the SC-CARM technique. The LD-TRO technique is recommended to prevent iatrogenic pneumothorax in dogs.

Evaluation of transpulmonary thermodilution as a method to measure cardiac output in anesthetized cats.

The objectives of this study were to evaluate the use of a transpulmonary thermodilution (Trans) technique for the measurement of cardiac output, and to determine the agreement between Trans and conventional thermodilution (TD) in anesthetized cats. Using each technique, cardiac output was measured in 5 mature cats (weights 2.4 to 5.6 kg) anesthetized with isoflurane. To induce different levels of cardiac output in each cat, anesthesia was maintained at > 1.5x end-tidal minimum alveolar concentration (MAC) of isoflurane, and at 1.3x end-tidal isoflurane MAC with and without administration of dobutamine. At least 2 comparisons between TD and Trans values were made at each cardiac output rate. Thirty-two of the 42 recorded comparisons were analyzed. Linear regression analysis (TD vs Trans) yielded an r(2) value of 0.83. The mean bias (TD-Trans) was -3.7 mL/kg/min with limits of agreement of -35.9 to 28.5 mL/kg/min. The concordance coefficient was 0.91. The Trans method showed good relationship and good agreement with TD in anesthetized cats. The Trans method is a relatively noninvasive, practical, and safe method to measure cardiac output in anesthetized cats.

Evaluation of factors affecting serum IgG concentrations in bottle-fed calves.

OBJECTIVE: To determine the effect of time interval from birth to first colostrum feeding on colostrum intake and serum IgG concentration and the effect of varying colostral volume intake and colostral IgG concentration on the probability of failure of passive transfer (FPT) in bottle-fed calves. DESIGN: Randomized controlled study. ANIMALS: 104 calves. PROCEDURES: Equal numbers of calves were randomly assigned to groups and fed 3 L of their dam's colostrum at 1, 2, 3, or 4 hours after birth by use of a nipple bottle. Calves were allowed to feed for 15 minutes, and intake was recorded. A second 3-L bottle feeding of colostrum was offered at 12 hours of age. RESULTS: 17.2% of calves ingested 3 L of colostrum at the first feeding and 3 L at 12 hours of age. Calf age, up to 4 hours, had no significant effect on the calf's ability to ingest colostrum or on 48-hour serum IgG concentration. Colostral intake at 1, 2, 3, or 4 hours had no effect on intake at the second feeding. Probability of FPT in calves ingesting 3 L at both feedings was < 0.05. CONCLUSIONS AND CLINICAL RELEVANCE: Allowing calves fed by nipple bottle to ingest as much colostrum as they can within 4 hours after birth and at 12 hours of age substantially reduced the probability of FPT. Bottle-fed calves that do not ingest 3 L of colostrum within the first 4 hours after birth should be targeted for oroesophageal intubation.

Effect of colostrum administration by use of oroesophageal intubation on serum IgG concentrations in Holstein bull calves.

OBJECTIVE: To determine the amount of colostral IgG required for adequate passive transfer in calves administered colostrum by use of oroesophageal intubation and evaluate the impact of other factors on passive transfer of colostral immunoglobulins in calves. ANIMALS: 120 Holstein bull calves. PROCEDURES: Calves were randomly assigned to specific treatment groups on the basis of volume of colostrum administered and age of calf at administration of colostrum. Colostrum was administered once by oroesophageal intubation. Equal numbers of calves received 1, 2, 3, or 4 L of colostrum, and equal numbers of calves received colostrum at 2, 6, 10, 14, 18, or 22 hours after birth. Serum samples were obtained from calves 48 hours after birth for IgG determination by radial immunodiffusion assay. Effects of factors affecting transfer of colostral immunoglobulins were determined by use of a stepwise multiple regression model and logistic regression models. RESULTS: A minimum of 153 g of colostral IgG was required for optimum colostral transfer of immunoglobulins when calves were fed 3L of colostrum at 2 hours after birth. Substantially larger IgG intakes were required by calves fed colostrum > 2 hours after birth. CONCLUSIONS AND CLINICAL RELEVANCE: Feeding 100 g of colostral IgG by oroesophageal intubation was insufficient for adequate passive transfer of colostral immunoglobulins. At least 150 to 200 g of colostral IgG was required for adequate passive transfer of colostral immunoglobulins. Use of an oroesophageal tube for administration of 3 L of colostrum to calves within 2 hours after birth is recommended.

Colostrum management in calves: effects of drenching vs. bottle feeding.

The objective was to examine whether the administration of colostrum by a drencher is a safe method to achieve satisfying immunoglobulin concentrations in newborn Holstein Friesian (HF)-calves. Twenty-one calves were fed 1 h postnatum with 2 l colostrum from their dam using a nipple bottle (group I); 15 calves were drenched with 4 l colostrum from their dam 1 h postnatum (group II). Thereafter, all calves were fed milk replacer exclusively. Serum concentration of total immunoglobulin [analysed by Sandwich-enzyme-linked immunosorbent assay (ELISA)] 24 h postnatum was higher in drenched calves (25.2 g/l; 12.8/52.2; median and 10/90 percentiles) compared with bottle-fed calves (14.1 g/l; 9.2/24.7). To characterize the kinetics of immunoglobulin absorption, 17 blood samples were taken frequently within 72 h postnatum using a jugular catheter in five calves fed 2 l colostrum by nipple bottle and five calves drenched with 4 l colostrum 1 h postnatum. A slightly delayed increase of serum immunoglobulin concentration (approximately 3 h) was obvious in drenched calves compared with bottle-fed calves, but drenched calves reached significantly higher immunoglobulin concentrations compared with bottle-fed calves. It is concluded that the proper application of colostrum by a drencher is a useful method for adequate colostral supply in newborn calves. The failure of the oesophageal groove reflex in drenched calves caused no clinical consequences.

Chronic implantation of transit-time flow probes on the ascending aorta of rodents.

This study describes the implantation of transit-time flow probes on the ascending aorta of rats while minimizing the risk of postoperative complications. Special emphasis is placed on our new method of rat intubation as well as the production of materials necessary for the implantation procedure such as endotracheal tubes and heparin bonded vessel catheters. The effects of these devices on the response to acute hypoxia were studied in rats following a 5-7 day recovery from the implantation procedure. Systemic and microvascular measurements were made on instrumented rats (n = 5) and non-instrumented controls (n = 3) that were ventilated with 21%, 15%, 10%, 8% and 5% oxygen. Arterial pressure, PO(2), lactate, and base deficit were not different between the implanted and control animals at any inspired oxygen concentration. Microvascular flow in the primary arterioles of the spinotrapezius muscle was also similar between the two groups at all inspired oxygen concentrations. We conclude that this novel methodology facilitates the measurement of whole body oxygen delivery in resting and haemodynamically-stressed rats.

Clinical use of low-profile cystostomy tubes in four dogs and a cat.

Traditional cystostomy tubes (used for temporary or permanent diversion of urine in dogs and cats) are long (> or = 22 cm) and cumbersome to stabilize, requiring sutures or bandages to hold the tube against the body. Use of a low-profile gastrostomy port system as a low-profile cystostomy tube (LPCT) in 4 dogs and a cat was investigated; owner satisfaction with the device was assessed. Technical difficulty associated with placement and management of LPCTs was similar to that for traditional cystostomy tubes; with LPCTs, activity and mobility of pets was not compromised, and bandaging was not required. Complications included lower urinary tract infection, mild peristomal leakage of urine and leakage from components of the system, and subcutaneous peristomal infection. Four of 5 owners considered the tube to be easy to use; all owners said they would be comfortable repeating their decision to use the LPCT in their pet.

Efficacy of different administration routes for vaccination against Vibrio anguillarum in Atlantic halibut (Hippoglossus hippoglossus L.).

Atlantic halibut (Hippoglossus hippoglossus L.) is a potentially important new species to cold-water aquaculture. Development of a viable industrial farming technique has been hampered by continued pathogen problems within the rearing cycle and there are several reports that indicated how susceptible juvenile halibut are to bacterial and viral diseases. Interest has been expressed, within the industry, over the possibility of vaccinating suitably sized animals to protect against the more common aquaculture pathogens. Vibrio spp. are of particular concern due to their ubiquitous nature and the relatively frequent occurrence of these pathogens within marine aquaculture. We have previously investigated the susceptibility of Atlantic halibut to infection by Vibrio anguillarum and the efficacy of intraperitoneal injected delivery of a commercial vaccine in protecting against the disease. Given the very high rate of protection offered by immunisation we wanted to investigate the effect of alternate routes of administration on the efficacy of the vaccine.