Comparison of 4 point-of-care techniques to detect correct positioning of nasogastric tubes in dogs (2020-2021).

OBJECTIVE: To compare 4 point-of-care (POC) techniques to assess nasogastric (NG) tube placement versus radiographs as a reference standard. POC methods included air inflation with auscultation, fluid aspiration with pH measurement, ultrasonography, and capnography. DESIGN: Prospective observational study in hospitalized dogs between 2020 and 2021. SETTING: University teaching hospital. ANIMALS: Fifty-one dogs requiring NG tube placement as part of their normal care. INTERVENTIONS: After standard blind NG tube placement, each POC method was performed following standardized instructions. All POC methods were scored as to whether the investigator believed the tube to be in the gastrointestinal tract (as indicated by positive auscultation of borborygmus during insufflation, positive fluid aspiration with pH ≤5, presence of hyperechoic shadow in the esophagus, or absence of capnographic waveform). Subsequently, radiographs were taken to determine NG tube position as a gold standard. The sensitivity, specificity, and accuracy of each test as compared to 2-view thoracic radiographs were determined. MEASUREMENTS AND MAIN RESULTS: Sensitivity, specificity, and accuracy for each POC technique were as follows: air auscultation (84.4%, 50.5%, and 80.4%, respectively), neck ultrasound (95.6%, 83.3%, and 94.1%, respectively), capnography (91.1%, 33.3%, and 84.3%, respectively), and fluid aspiration with pH measurement (22.2%, 100%, and 31.4%, respectively). CONCLUSIONS: Among the 4 techniques evaluated, neck ultrasound had the best overall performance for assessing NG tube placement. Fluid aspiration with pH measurement might also have potential due to perfect specificity, but its clinical utility may be limited by low sensitivity and accuracy. Nonetheless, 2-view thoracic radiography should still be considered the standard method for confirmation of NG tube placement as none of the 4 POC techniques investigated showed both high sensitivity and perfect specificity.

Outcomes, including death, in dogs with pneumothorax following nasogastric feeding tube misplacement in the tracheobronchial tree: 13 cases (2017-2022).

OBJECTIVE: Complications of feeding tube placement are uncommon, but life-threatening pneumothorax has been reported in human and veterinary patients during feeding tube placement. This article describes the development of pneumothorax and the outcome associated with misplacement of nasogastric (NG) tubes in the tracheobronchial tree in 13 dogs. ANIMALS: 13 dogs being treated for various medical conditions that had NG tubes placed in 4 hospitals. PROCEDURES: A review was carried out of the medical records of 13 dogs that developed pneumothorax after misplacement of NG tubes between 2017 and 2022. RESULTS: 14 dogs out of 4,777 (0.3%) developed pneumothorax as an adverse effect of NG tube misplacement in the tracheobronchial tree. One dog was excluded due to incomplete medical records. The feeding tube size ranged from 5F to 10F, and the most common tubes utilized were polyurethane tubes with flushing stylets. Nine out of 13 dogs developed evidence of respiratory compromise after the NG tube was placed. Eleven dogs required thoracocentesis, and 5 dogs had thoracostomy tubes placed. Five dogs suffered cardiopulmonary arrest after developing pneumothorax, with 3 of 5 undergoing cardiopulmonary resuscitation. Two out of 3 dogs that underwent cardiopulmonary resuscitation were discharged from the hospital. Five of 13 dogs were successfully discharged from the hospital, while 5 dogs died or were euthanized because of the pneumothorax. CLINICAL RELEVANCE: Pneumothorax is a rare but potentially life-threatening complication of NG tube placement in dogs and may lead to death if not immediately addressed. Practitioners should be aware of this complication and be ready to perform thoracocentesis quickly if appropriate.

Use of feeding tubes in 112 cats in an internal medicine referral service (2015-2020).

OBJECTIVES: The aims of this study were to describe diseases, complications and outcomes associated with the use of feeding tubes in a population of sick cats with appetite disturbance managed at an internal medicine referral service. METHODS: Clinicopathological data from cats receiving nasoenteral (NE) or oesophagostomy (O) tubes were studied. Cats were categorised according to their underlying disease and divided into subgroups (NE or O tube). The following factors associated with survival were analysed: disease category, type of tube and return to appetite. RESULTS: Included in the study were 112 cats, representing 118 cases. Of the 118 cases, 98 (83%) and 20 (17%) received NE or O tubes, respectively. The most common underlying conditions were digestive (13.5%), hepatobiliary (11%) and upper urinary tract (11%) disorders. Hepatobiliary (50%) and upper respiratory tract (30%) conditions were predominant in the O tube group. Digestive (15%) and upper urinary tract (12%) diseases were more common in the NE tube group. Complications following tube placement occurred in 22/118 cases (18.6%). The global survival rate was 73% and did not differ between NE (71.4%) and O tube (80%) groups (P = 1.00) or disease categories (P = 0.61). Return of appetite before feeding tube removal occurred in 56 cases (47%), within a median of 3 days (range 1-30) and was not associated with mirtazapine administration (P = 1.00). Appetite returned earlier for cats with NE tubes (3 days, range 1-17) than for those with O tubes (33 days, range 5-60; P <0.05). Voluntary food intake was positively associated with survival (odds ratio 15.17). After discharge and feeding tube retrieval, return of appetite was observed in 67% of cases. CONCLUSIONS AND RELEVANCE: Feeding tubes were predominantly placed for the management of appetite disturbance in cats with digestive, hepatobiliary and upper urinary tract diseases. While complications were frequent, they were mostly mild, easily managed and did not preclude feeding tube use. Return to appetite occurred in a large proportion of cats during or after assisted enteral feeding and was associated with survival.

Fatal Complications of Nasogastric Tube Misplacement in Two Dogs.

Provision of enteral nutrition via the use of nasoenteric feeding tubes is a commonly used method in both veterinary and human medicine. Although case reports in human medicine have identified fatalities due to misplacement of nasogastric (NG) tubes into the tracheobronchial tree and subsequent pneumothorax, there are no case reports, to our knowledge, of fatalities in veterinary patients. This case report describes two fatalities caused by misplaced NG tubes in intubated patients (one intraoperative, one postoperative). This report highlights risk factors for feeding tube complications and methods to prevent future fatalities such as two-view radiography, two-step insertion, capnography, laryngoscopic-assisted placement, and palpation of the NG tube in the stomach. The recent fatalities discussed within this case series demonstrate that deaths as a result of NG tubes misplaced into the tracheobronchial tree occur in veterinary patients, and measures should be taken to prevent this complication.

Verifying the placement and length of feeding tubes in canine and feline neonates.

BACKGROUND: Tube feeding is a common procedure in neonatology. In humans, tube misplacement reportedly occurs in up to 59% of all cases and may lead to perforation in 1.1% of preterm intubated neonates. While numerous studies on optimal tube placement have been performed in human neonates, current recommendations on tube feeding in canine and feline neonatology are based, at best, on studies performed in adult animals. Herein, we aimed to test ultrasonography as a tool to verify tube placement in puppies and kittens and to compare different anatomical predictive markers used in human, canine and feline neonates. RESULTS: The predictive tube length when held bent between the last rib and the mouth may induce trauma compared to when held straight. A strong positive linear correlation was observed between birthweight and gastric cardia localization. Ultrasonography findings were similar to coeliotomy findings. Stomach volume was less than 2 mL per 100 g in the less-than-one-day-old studied puppies (n = 25) and kittens (n = 28). CONCLUSIONS: A weight-based equation was calculated to help predict appropriate tube placement. Ultrasonography can be used to control gastric tube placement, and neonates less than one-day-old have a smaller stomach capacity. Further studies are required to evaluate whether more-than-one-day-old puppies follow the same linear correlation with their weight. Further in vivo studies are warranted to determine the gold standard procedure for tube feeding in neonatal puppies and kittens.

Evaluation of a novel non-surgical post-pyloric feeding technique in dogs with severe acute kidney injury.

OBJECTIVES: To evaluate the placement and the performance of a new post-pyloric feeding (PPF) system, and compare it to esophageal (E) feeding in dogs with severe acute kidney injury (AKI). DESIGN: Prospective study. SETTING: University teaching hospital. ANIMALS: Twenty client-owned dogs with severe AKI treated with hemodialysis. INTERVENTIONS: Dogs were randomly assigned to 2 feeding techniques, PPF or E feeding; for PPF, an 8-Fr jejunal (J) tube was introduced through a standard 18-Fr E-tube and advanced endoscopically through the pylorus. A commercial liquid diet was administered at a continuous rate for at least 5 days. After the removal of the internal J-tube, feeding was continued through the E-tube. Control dogs were fed blended food 5 times daily through an E-tube. Placement technique, nutritional efficiency, and metabolic response to nutritional support were compared between the groups. MEASUREMENTS AND MAIN RESULTS: Feeding tubes were placed a medium of 1 day (interquartile range, 0.8 d) after presentation. Median procedure-time in the group PPF was 26.5 min (11.5 min), including 8.5 min (2.7 min) for the E-tube and 17.5 min (5.0 min) for the J-tube. J-tubes were used for 5 days (1.5 d) with oral displacement observed in 3/10 dogs. The goal to administer 130% resting energy requirement within 3 days was reached in 13/20 dogs (8/10 PPF, 5/10 E). Despite nutritional support, dogs lost 1.2% body weight per day (1.1%), with no difference between the groups. The metabolic improvement was comparable between the groups, despite marked differences in the diet composition. CONCLUSIONS: This new feeding technique can be recommended as an efficient method for early nutritional support in dogs with severe AKI. The protein-energy wasting observed despite active nutritional support suggests, however, the necessity for increased feeding targets or qualitative changes in diet composition for dogs with AKI.

Nasogastric Intubation as Health and Safety Risk in Equine Practice-A Questionnaire.

Placing a nasogastric tube can be a life-saving act for a horse but is considered an occupational hazard for veterinarians. An online questionnaire was performed to assess and specify potential risks. 123 equine veterinarians completed the survey, and the majority admitted using the mouth to handle the end of the nasogastric tube (sucking or blowing air) and having accidentally swallowed or aspirated stomach content or medications. This can potentially lead to aspiration pneumonia or pneumonitis. Mineral oil seems to be especially dangerous as aspiration may be asymptomatic at the beginning and lipoid pneumonitis may develop. Furthermore, 60% of responders would also handle the tube with their mouth if the horse was presented with fever and diarrhea or reflux formation, which might be affected by Salmonella sp. or Clostridium difficile producing toxins. The fact that nasogastric tubes are rarely being disinfected increases the risk of infection. 50% of veterinarians would use their mouth to suck or blow air into the tube during nasogastric intubation, even if the patient was presented with suspected poisoning. Rodenticide zinc phosphide is particularly dangerous as its breakdown product is a highly toxic gas. Inhalation leads to serious symptoms in humans, including pulmonary edema and neurological signs. Alternatives to mouth use (lavage, big syringe, or suction pump) when passing a tube should be considered, especially if a patient is presented with duodenitis-proximal jejunitis, diarrhea, or suspected poisoning. Awareness needs to be raised among veterinarians that nasogastric intubation is an extremely hazardous occupational practice.

Description of a novel technique for surgical placement of gastrostomy tubes in dogs.

BACKGROUND: Early enteral nutrition in dogs with critical illnesses, including septic peritonitis, has been shown to have a positive influence on patient outcome. Surgical placement of a gastrostomy tube (GT) is one option for providing early enteral nutrition. Complications, including premature tube removal or separation of the stomach from the body wall, can result in leakage of gastric contents into the abdominal cavity and subsequent peritonitis. A safe and reliable technique for the placement of a GT is desirable to minimize such complications. KEY CONCEPTS: A modified method for surgical placement of a GT is described. A thoracic trocar catheter (TTC) with an attached Pezzer tube is inserted through a gastrotomy incision and exited through the left gastric body and body wall. A left-sided tube gastropexy is performed using an interlocking box (ILB) pattern. SIGNIFICANCE: GT placement using a TTC is efficient, requiring minimal additional anesthesia time. The gastric defect created by the TTC conforms well with the Pezzer tube. As such, placement and utilization of the ILB suture pattern enables removal of the GT in the early postoperative period, if appropriate.

Retrospective evaluation of 24 cases of gastrostomy tube usage in dogs with septic peritonitis (2009-2016).

OBJECTIVE: To describe the postoperative use of gastrostomy tubes (GT) in dogs with septic peritonitis. A secondary objective was to identify factors associated with GT placement and use that may be related to outcome. DESIGN: Retrospective study. SETTING: University teaching hospital. ANIMALS: Twenty-four dogs diagnosed with septic peritonitis with GT placement at the time of exploratory laparotomy. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Eighteen dogs (75%) survived to discharge. Eighteen dogs (75%) had a gastrointestinal source of septic peritonitis. Complications were reported in 12/24 (50%) patients. Four dogs (16.6%) had non-GT-related complications such as vomiting, regurgitation, or increased gastric residual volume. GT-related complications occurred in 8/24 (33.3%) dogs, the majority of which (6/8 [75%]) were minor and did not necessitate removal of the GT. Two dogs had major complications that required removal of the GT. Significant differences between survivors and nonsurvivors were found between the length of time after placement of the GT to when they began eating and outcome (discharge versus death versus euthanasia) (P = 0.03), and GT dwell time (length of time the GT was in place) and outcome (P = 0.006). Clinically relevant correlations were found between the time after placement of the GT until feeding and time after placement until voluntarily eating (P = 0.0349), time after placement of the GT until voluntarily eating and length of hospitalization (P = 0.0391), and time after placement of the GT until feeding and length of hospitalization (P = 0.036). CONCLUSIONS: GTs can be placed during exploratory laparotomy in dogs with septic peritonitis. They facilitate early enteral nutrition and are associated with few clinically significant complications. Prospective studies are needed to determine the optimal postoperative feeding plan and the effects of early enteral nutrition on serum albumin concentration in this patient population.

Pharmacokinetics and pharmacodynamics of olopatadine following administration via nasogastric tube to healthy horses.

OBJECTIVE: To investigate the pharmacokinetics and antihistaminic effects (pharmacodynamics) of olopatadine in a small population of healthy horses after administration via nasogastric tube. ANIMALS: 4 healthy adult Thoroughbreds. PROCEDURES: Olopatadine (0.1 mg/kg, once) was administered via nasogastric tube. Blood samples were collected at predetermined time points for pharmacokinetic analyses of the drug in plasma. Olopatadine effects were investigated by measurement of cutaneous wheals induced by ID histamine injection (0.1 mL [10 µg]/injection) at predetermined time points. Inhibition effect ratios were calculated on the basis of measured wheal size (area) after versus before olopatadine administration. RESULTS: Mean ± SD maximum plasma olopatadine concentration was 48.8 ± 11.0 ng/mL approximately 1.5 hours after administration. Median terminal half-life was 6.11 hours. Mean ± SD maximal effect was 88.2 ± 4.9% inhibition approximately 3.5 hours after drug delivery, and the inhibition effect remained > 80% for 12.5 hours after treatment. No signs of adverse clinical effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested olopatadine may have a strong, long-term inhibitory effect against histamine-induced wheals in the skin of horses. Clinical research with a larger number of horses is warranted.

Retrospective evaluation of the route and timing of nutrition in dogs with septic peritonitis: 68 cases (2007-2016).

OBJECTIVE: To determine the impact of route of nutrition on length of hospitalization and survival to discharge in dogs with septic peritonitis. DESIGN: Retrospective study from 2007 to 2016. SETTING: University teaching hospital. ANIMALS: Sixty-eight dogs with septic peritonitis that survived ≥48 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Nutritional strategy was categorized into 1 of 4 groups: voluntary, feeding tube, parenteral (PN), and combined feeding tube and PN. Body weight, body condition score, time without caloric intake before and during hospitalization, length of hospitalization, and percentage of resting energy requirements provided during the first 3 days of nutritional support were recorded. Overall, 54/68 dogs survived (79%). Survival Prediction Index 2 scores were not significantly different between groups. Dogs receiving PN only were less likely to survive than those receiving any enteral nutrition (OR 9.7; 95CI 1.84-58.75). Compared to dogs not receiving PN, dogs receiving any PN were significantly less likely to survive (OR 9.66; 95% CI 1.7-105.8), and were in hospital significantly longer (P = 0.025). Metabolic complications associated with PN were frequent but not associated with increased length of hospitalization or survival to discharge. CONCLUSIONS: Dogs with septic peritonitis that received any PN were in hospital longer and less likely to survive but may have been sicker than those receiving other forms of nutritional support. Further studies are warranted to evaluate reasons for worse outcomes in dogs with septic peritonitis receiving PN.

Hypotonic enteral electrolyte solutions administered by nasoesophageal tube in continuous flow in dogs dehydrated by water restriction: Part 1 / Soluções eletrolíticas enterais hipotônicas administradas por sonda nasoesofágica em fluxo contínuo em cães desidratados por restrição hídrica: Parte 1

The present study assessed and compared the effects of hypotonic enteral electrolyte solutions administered by nasoesophageal tube in continuous flow in dogs submitted to water restriction on packed cell volume; total serum protein and serum osmolarity concentrations; blood volume; plasma glucose and lactate levels; blood gas analysis, anion gap, and strong ion difference. Six adult dogs were used (four males and two females). All animals were submitted to both proposed treatments in a crossover design 6×2. The treatments were as follows: ESmalt consisting of 5g sodium chloride, 1g potassium chloride, 1g calcium acetate, 0.2g magnesium pidolate, and 9.6g maltodextrin that were diluted in 1.000mL water (measured osmotic concentration of 215mOsm L−1) and ESdext consisting of 5g sodium chloride, 1g potassium chloride, 1g calcium acetate, 0.2g magnesium pidolate, and 9.6g dextrose that were diluted in 1.000mL water (measured osmotic concentration of 243mOsm L−1). All solutions were administered at 15ml kg−1 h−1 for 4 hours. Both solutions increased the plasma volume in dehydrated dogs without causing adverse effects. However, ESmalt was more effective in promoting the increase in blood volume.(AU)

O presente estudo avaliou e comparou os efeitos de soluções eletrolíticas enterais hipotônicas, administradas por sonda nasoesofágica em fluxo contínuo em cães submetidos a restrição hídrica, sobre o hematócrito, proteínas totais séricas, osmolaridade sérica, volemia, glicose e lactato plasmáticos, hemogasometria, ânion gap e DIF. Foram utilizados seis cães adultos (quatro machos e duas fêmeas). Todos os animais foram submetidos aos dois tratamentos propostos, em um delineamento crossover 6×2. Os tratamentos foram os seguintes: SEmalt - 5g de cloreto de sódio, 1g de cloreto de potássio, 1g de acetato de cálcio, 0,2g de pidolato de magnésio e 9,6g de maltodextrina, diluídos em 1.000mL de água (osmolaridade mensurada: 215mOsm L -1 ); SEdext - 5g de cloreto de sódio, 1g de cloreto de potássio, 1g de acetato de cálcio, 0,2g de pidolato de magnésio e 9,6g de dextrose, diluídos em 1.000mL de água (osmolaridade mensurada: 243mOsm L -1 ). Todas as soluções foram administradas no volume de 15mL kg -1 hora -1 , durante quatro horas, em fluxo contínuo. Ambas as soluções aumentaram o volume plasmático em cães desidratados, sem gerar o aparecimento de efeitos adversos. Porém, a SEmalt foi mais eficaz em promover a expansão da volemia.

Continuous fluid infusion per rectum compared with intravenous and nasogastric fluid administration in horses.

BACKGROUND: Rectal fluid administration may offer a simple, safe and inexpensive alternative to intravenous or nasogastric fluid therapy in equine clinical cases. OBJECTIVES: To evaluate the tolerance and effects of rectally administered fluid and compare the measurements of haemodilution and intravascular volume with those during nasogastric and intravenous fluid administration. STUDY DESIGN: Randomised controlled experimental trial. METHODS: Six clinically normal Standardbred geldings were used in a 4-way crossover study: each received three different fluid treatments (intravenous, nasogastric and rectal) at 5 mL/kg/h for 6 h and underwent a control (no treatment) with water and feed withheld. Bodyweight was measured at baseline and 6 h. Packed cell volume (PCV), total solids (TS), albumin, electrolytes, lactate, urine specific gravity, vital parameters, gastrointestinal borborygmi and central venous pressure were measured every 2 h. RESULTS: Rectal fluid administration with plain water was well tolerated and caused clinical chemistry changes consistent with haemodilution, indicating absorption. Mean (95% confidence interval) PCV decreased from 40% [40-42] at 0 h to 35% [34-36] at 6 h during rectal fluid treatment (P<0.001), similar to decreases in PCV occurring also with i.v. and nasogastric (NGT) treatment (P<0.001). The TS also decreased with i.v. and rectal fluid (P<0.001). There was a decrease in bodyweight in the control (P<0.001) but not with any of the fluid treatments. MAIN LIMITATIONS: A small sample size of healthy, euhydrated horses and a relatively short duration of fluid administration was used. CONCLUSIONS: Rectal fluid administration requires clinical evaluation, but may offer an inexpensive, safe alternative or adjunct to i.v. fluid administration, particularly when administration via NGT is not possible or contraindicated. The Summary is available in Portuguese - see Supporting Information.

Clinical experience utilizing a novel fluoroscopic technique for wire-guided esophagojejunal tube placement in the dog and cat: Twenty cases (2010-2013).

OBJECTIVE: To describe the clinical use of a novel, minimally invasive technique for fluoroscopic wire-guided esophagojejunal tube (FEJT) placement in dogs and cats. DESIGN: Retrospective study (February 2010-September 2013). SETTING: University veterinary teaching hospital. ANIMALS: Eighteen dogs and 2 cats with intolerance of, or contraindications to, gastric feeding that underwent attempted FEJT placement. INTERVENTIONS: All patients underwent attempted FEJT placement using a novel fluoroscopic wire-guided technique. MEASUREMENTS AND MAIN RESULTS: Patient data were collected including information about the FEJT placement and utilization of the tube postplacement. The primary diagnosis in dogs undergoing FEJT placement was pancreatitis in 61% of cases. The ability to achieve postpyloric access with the technique was 95% (19/20). Mean duration of the procedure in dogs where FEJT placement was successful was 63.8 minutes (SD, 28.6; min-max, 30-120 min). Mean fluoroscopy time was 19.4 minutes (SD, 11.5; min-max, 5.2-42.1-min). Esophagostomy site infection was a complication of FEJT placement in 2 dogs. The mean duration the FEJT remained in place in dogs was 3.8 days (SD, 2.2; min-max, 1-7 days), and mean duration of feeding was 3.6 days (SD, 2.2; min-max, 1-7 days). Vomiting was noted in 89% of patients prior to FEJT placement and was significantly reduced to only 24% of patients postplacement (P = 0.0001). CONCLUSIONS: FEJT placement is a viable technique for providing postpyloric nutrition in dogs and cats intolerant of, or with contraindications to, gastric feeding.

Pharmacokinetics of harpagoside in horses after intragastric administration of a Devil's claw (Harpagophytum procumbens) extract.

Devil's claw is used for the treatment of inflammatory symptoms and degenerative disorders in horses since many years, but without the substantive pharmacokinetic data. The pharmacokinetic parameters of harpagoside, the main active constituent of Harpagophytum procumbens DC ex Meisn., were evaluated in equine plasma after administration of Harpagophytum extract FB 8858 in an open, single-dose, two-treatment, two-period, randomized cross-over design. Six horses received a single dose of Harpagophytum extract, corresponding to 5 mg/kg BM harpagoside, and after 7 days washout period, 10 mg/kg BM harpagoside via nasogastric tube. Plasma samples at certain time points (before and 0-24 hr after administration) were collected, cleaned up by solid-phase extraction, and harpagoside concentrations were determined by LC-MS/MS using apigenin-7-glucoside as internal standard. Plasma concentration-time data and relevant parameters were described by noncompartmental model through PKSolver software. Harpagoside could be detected up to 9 hr after administration. Cmax was found at 25.59 and 55.46 ng/ml, t1/2 at 2.53 and 2.32 hr, respectively, and tmax at 1 hr in both trials. AUC0-inf was 70.46 and 117.85 ng hr ml-1 , respectively. A proportional relationship between dose, Cmax and AUC was observed. Distribution (Vz /F) was 259.04 and 283.83 L/kg and clearance (CL/F) 70.96 and 84.86 L hr-1  kg-1 , respectively. Treatment of horses with Harpagophytum extract did not cause any clinically detectable side effects.

Oral Intubation of Adult Zebrafish: A Model for Evaluating Intestinal Uptake of Bioactive Compounds.

Most pathogens invade organisms through their mucosa. This is particularly true in fish as they are continuously exposed to a microbial-rich water environment. Developing effective methods for oral delivery of immunostimulants or vaccines, which activate the immune system against infectious diseases, is highly desirable. In devising prophylactic tools, good experimental models are needed to test their performance. Here, we show a method for oral intubation of adult zebrafish and a set of procedures to dissect and prepare the intestine for cytometry, confocal microscopy and quantitative polymerase chain reaction (qPCR) analysis. With this protocol, we can precisely administer volumes up to 50 µL to fish weighing approximately 1 g simply and quickly, without harming the animals. This method allows us to explore the direct in vivo uptake of fluorescently labelled compounds by the intestinal mucosa and the immunomodulatory capacity of such biologics at the local site after intubation. By combining downstream methods such as flow cytometry, histology, qPCR and confocal microscopy of the intestinal tissue, we can understand how immunostimulants or vaccines are able to cross the intestinal mucosal barriers, pass through the lamina propria, and reach the muscle, exerting an effect on the intestinal mucosal immune system. The model could be used to test candidate oral prophylactics and delivery systems or the local effect of any orally administered bioactive compound.

Effects of Sampling Techniques and Sites on Rumen Microbiome and Fermentation Parameters in Hanwoo Steers.

We evaluated the influence of sampling technique (cannulation vs. stomach tube) and site (dorsal sac vs. ventral sac) on the rumen microbiome and fermentation parameters in Hanwoo steers. Rumen samples were collected from three cannulated Hanwoo steers via both a stomach tube and cannulation, and 16S rRNA gene amplicons were sequenced on the MiSeq platform to investigate the rumen microbiome composition among samples obtained via 1) the stomach tube, 2) dorsal sac via rumen cannulation, and 3) ventral sac via rumen cannulation. A total of 722,001 high-quality 16S rRNA gene sequences were obtained from the three groups and subjected to phylogenetic analysis. There was no significant difference in the composition of the major taxa or alpha diversity among the three groups (p＞ 0.05). Bacteroidetes and Firmicutes represented the first and second most dominant phyla, respectively, and their abundances did not differ among the three groups (p＞ 0.05). Beta diversity principal coordinate analysis also did not separate the rumen microbiome based on the three sample groups. Moreover, there was no effect of sampling site or method on fermentation parameters, including pH and volatile fatty acids (p ＞ 0.05). Overall, this study demonstrates that the rumen microbiome and fermentation parameters are not affected by different sampling techniques and sampling sites. Therefore, a stomach tube can be a feasible alternative method to collect representative rumen samples rather than the standard and more invasive method of rumen cannulation in Hanwoo steers.

Incidence of hypochloremic metabolic alkalosis in dogs and cats with and without nasogastric tubes over a period of up to 36 hours in the intensive care unit.

OBJECTIVE: To evaluate the incidence of hypochloremic metabolic alkalosis (HCMA) in dogs and cats in the ICU that had intermittent nasogastric tube (NGT) aspiration for up to 36 hours. DESIGN: Prospective cohort study (December 2013 to October 2014). SETTING: Privately owned emergency and referral teaching hospital. ANIMALS: Forty-nine client-owned dogs and 16 client-owned cats. INTERVENTIONS: Patients wherein NGT placement was recommended and client consent was obtained were included in the interventional group. Those with an NGT placed (NGT group) had the NGT aspirated every 4 hours. Patients for whom placement of a NGT was declined by the owner served as a reference group (NoNGT). Venous blood gas and electrolyte values were obtained every 12 hours. MEASUREMENTS AND MAIN RESULTS: Thirty-five dogs and cats had an NGT placed. Thirty dogs and cats did not have an NGT placed. The serum venous blood gas and electrolyte changes were compared over time within the NGT group and between the NGT and NoNGT groups. No cases developed HCMA. In the NGT group, blood pH increased over time. There was no significant difference between the NGT and the NoNGT group in the average value of pH, HCO3- , base excess, chloride, or corrected chloride. Serum venous blood gas, chloride, and corrected chloride changes were not associated with the volumes of gastric fluid aspirated over time. CONCLUSIONS: In this small population of dogs and cats, intermittent NGT aspiration was not associated with the development of HCMA over a period of up to 36 hours after NGT placement.

Evaluation of various gastrojejunostomy tube constructs for enteral support of small animal patients.

OBJECTIVE To evaluate the feasibility of manufacturing gastrojejunostomy tubes from jejunostomy and gastrostomy tubes that would allow for gastric and enteral feeding of and aspiration of gastric contents from small animal patients. DESIGN In vitro study. SAMPLE 9 gastrojejunostomy constructs. PROCEDURES Commercially available gastrostomy and jejunostomy tubes were combined to create 9 constructs. Three investigators tested each construct with 4 solutions (tap water, a commercial enteral diet, and 2 canned food-water mixtures) and 3 syringe sizes for ease of injection through the gastrostomy and jejunostomy tubes and aspiration through the gastrostomy tube. Flow rates were calculated and analyzed to evaluate effects of tube diameter and syringe size for each solution. RESULTS The 20F/8F, 24F/8F, 28F/8F, and 28F/10F (gastrostomy tube/jejunostomy tube) constructs allowed for injection and aspiration of all solutions. The 5F jejunostomy tubes allowed only water to be injected, whereas the 8F jejunostomy tubes did not allow injection of the canned food-water mixtures. The 20F/10F construct did not allow injection or aspiration through the gastrostomy tube, whereas the 18F/8F construct allowed injection but not aspiration through the gastrostomy tube. Faster flow rates through the gastrostomy tube were associated with larger gastrostomy tube diameter, smaller jejunostomy tube diameter, and smaller syringe size. Faster flow rates through the jejunostomy tube were associated with smaller jejunostomy tube diameter. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that homemade gastrojejunostomy constructs would allow for administration of a variety of enteral diets. Limitations to the administration and aspiration of various enteral diets as well as patient needs should be considered before a gastrojejunostomy tube combination is chosen.

Retrospective analysis of insulin responses to standard dosed oral glucose tests (OGTs) via naso-gastric tubing towards definition of an objective cut-off value.

BACKGROUND: Insulin dysregulation (ID) with basal or postprandial hyperinsulinemia is one of the key findings in horses and ponies suffering from the equine metabolic syndrome (EMS). Assessment of ID can easily be performed in clinical settings by the use of oral glucose challenge tests. Oral glucose test (OGT) performed with 1 g/kg bodyweight (BW) glucose administered via naso-gastric tube allows the exact administration of a defined glucose dosage in a short time. However, reliable cut-off values have not been available so far. Therefore, the aim of the study was to describe variations in insulin response to OGT via naso-gastric tubing and to provide a clinical useful cut-off value for ID when using the insulin quantification performed with an equine-optimized insulin enzyme-linked immunosorbent assay. RESULTS: Data visualization revealed no clear separation in the serum insulin concentration of insulin sensitive and insulin dysregulated horses during OGT. Therefore, a model based clustering method was used to circumvent the use of an arbitrary limit for categorization. This method considered all data-points for the classification, taking into account the individual insulin trajectory during the OGT. With this method two clusters were differentiated, one with low and one with high insulin responses during OGT. The cluster of individuals with low insulin response was consistently detected, independently of the initialization parameters of the algorithm. In this cluster the 97.5% quantile of insulin is 110 µLU/mL at 120 min. We suggest using this insulin concentration of 110 µLU/mL as a cut-off value for samples obtained at 120 min in OGT. CONCLUSION: OGT performed with 1 g/kg BW glucose and administration via naso-gastric tubing can easily be performed under clinical settings. Application of the cut-off value of 110 µLU/mL at 120 min allows assessment of ID in horses.