Evaluation of a laryngotomy approach for near-total resection of the nasal septum in the horse.

OBJECTIVE: To report a laryngotomy approach for the removal of the nasal septum in adult horses. STUDY DESIGN: Descriptive study. ANIMALS: Horses (n = 10). METHODS: Near-total resection of the nasal septum was made using a modification of a previously reported 3-wire technique using a trephination approach and a 2-wire technique using a laryngotomy approach. Surgical time, ease of technique, complications, and outcome were recorded. At 45 days, horses were euthanatized and septal measurements made. RESULTS: Near-total resection of the nasal septum was accomplished with both techniques without complications. Incisional complications occurred in the trephination group and transient granulation tissue formation near the rostral stump occurred in the laryngotomy group. The laryngotomy technique was technically easier and resulted in a more cosmetic outcome. CONCLUSIONS: A laryngotomy approach is safe and expedient for near-total resection of the nasal septum with minimal complications.

Comparative pharmacokinetics of meloxicam in clinically normal horses and donkeys.

OBJECTIVE: To determine the disposition of a bolus of meloxicam (administered IV) in horses and donkeys (Equus asinus) and compare the relative pharmacokinetic variables between the species. ANIMALS: 5 clinically normal horses and 5 clinically normal donkeys. PROCEDURES: Blood samples were collected before and after IV administration of a bolus of meloxicam (0.6 mg/kg). Serum meloxicam concentrations were determined in triplicate via high-performance liquid chromatography. The serum concentration-time curve for each horse and donkey was analyzed separately to estimate standard noncompartmental pharmacokinetic variables. RESULTS: In horses and donkeys, mean +/- SD area under the curve was 18.8 +/- 7.31 microg/mL/h and 4.6 +/- 2.55 microg/mL/h, respectively; mean residence time (MRT) was 9.6 +/- 9.24 hours and 0.6 +/- 0.36 hours, respectively. Total body clearance (CL(T)) was 34.7 +/- 9.21 mL/kg/h in horses and 187.9 +/- 147.26 mL/kg/h in donkeys. Volume of distribution at steady state (VD(SS)) was 270 +/- 160.5 mL/kg in horses and 93.2 +/- 33.74 mL/kg in donkeys. All values, except VD(SS), were significantly different between donkeys and horses. CONCLUSIONS AND CLINICAL RELEVANCE: The small VD(SS) of meloxicam in horses and donkeys (attributed to high protein binding) was similar to values determined for other nonsteroidal anti-inflammatory drugs. Compared with other species, horses had a much shorter MRT and greater CL(T) for meloxicam, indicating a rapid elimination of the drug from plasma; the even shorter MRT and greater CL(T) of meloxicam in donkeys, compared with horses, may make the use of the drug in this species impractical.

Pharmacokinetics of R(-) and S(+) carprofen after administration of racemic carprofen in donkeys and horses.

OBJECTIVE: To compare plasma disposition of the R(-) and S(+) enantiomers of carprofen after IV administration of a bolus dose to donkeys and horses. ANIMALS: 5 clinically normal donkeys and 3 clinically normal horses. PROCEDURE: Blood samples were collected from all animals at time 0 (before) and at 10, 15, 20, 30, and 45 minutes and 1, 1.5, 2, 2.5, 3, 4, 5, 6, 8, 10, 24, 28, 32, and 48 hours after IV administration of a bolus of carprofen (0.7 mg/kg). Plasma was analyzed in triplicate via high-performance liquid chromatography to determine the concentrations of the carprofen enantiomers. A plasma concentrationtime curve for each donkey and horse was analyzed separately to estimate noncompartmental pharmacokinetic variables. RESULTS: In donkeys and horses, the area under the plasma concentration versus time curve (AUC) was greater for the R(-) carprofen enantiomer than it was for the S(+) carprofen enantiomer. For the R(-) carprofen enantiomer, the AUC and mean residence time (MRT) were significantly less and total body clearance (CIT) was significantly greater in horses, compared with donkeys. For the S(+) carprofen enantiomer, AUC and MRT were significantly less and CIT and apparent volume of distribution at steady state were significantly greater in horses, compared with donkeys. CONCLUSIONS AND CLINICAL RELEVANCE: Results have suggested that the dosing intervals for carprofen that are used in horses may not be appropriate for use in donkeys.

Spiral colon bypass in a geriatric Vietnamese potbellied pig.

An 8-year-old potbellied pig was evaluated for anorexia, decreased fecal production, signs of depression, inappetence, and abdominal distension. During hospitalization, a tooth root impaction and abscess were diagnosed, and abdominal radiography revealed severely distended, gas-filled large and small intestines. Exploratory laparotomy revealed a stricture of the proximal centripetal loop of the spiral colon and megacolon of the proximal portion of the spiral colon and cecum. A side-to-side spiral colon anastomosis was performed to create a partial bypass of the spiral colon. The success of this procedure suggests that spiral colon bypass is a treatment option for spiral colon stricture formation in potbellied pigs. Spiral colon stricture formation should be considered as a differential diagnosis in geriatric potbellied pigs that are anorectic, have abdominal distension, and have decreased fecal production.

Endoscopic antireflux treatment: fact, fiction or future?

Medical therapy with proton pump inhibitors (PPIs), aside from surgery, is the established and most effective treatment approach for chronic gastroesophageal reflux disease (GERD). Recently developed endoscopic antireflux procedures may be an alternative for a subset of patients with uncomplicated, mild GERD. Given the perioperative morbidity and mortality risk of laparoscopic fundoplication, less invasive semi-surgical and flexible endoscopic techniques may be an option for patients who cannot or wish not to take long-term medication. These clinical procedures include endoscopic suturing devices, focal radiofrequency coagulation in the cardia and bioimplants. While many of these techniques have shown good results in preliminary studies, long-term results are not yet available and therefore all such procedures have to be considered experimental. Their effectiveness will need to be compared with that of established treatment forms.

Management of difficult common bile duct stones.

More than 80% of all CBD stones can be effectively treated by endoscopic sphincterotomy and stone extraction using baskets or balloon catheters. For stones up to 2.5 cm in diameter, mechanical lithotripsy is the method of choice as a next step. Very large, impacted, or very hard concretions, however, often make mechanical lithotripsy cumbersome or even impossible. For these stones laser lithotripsy, EHL, and ESWL are nonoperative options, especially for elderly patients and patients with an elevated surgical risk. Because these methods are often only available at endoscopic centers, stenting is a treatment modality for immediate stone therapy, but as a definitive treatment it should be restricted to selected cases. ESWL, EHL, and laser lithotripsy yield similar success rates of 80% to 95% and may be used complementarily in endoscopic centers. ESWL is the preferred therapy in intrahepatic lithiasis. Laser lithotripsy shows the best results in CBD stones. Electrohydraulic lithotripsy is rarely used because of its high potential for tissue damage and bleeding. Laser lithotripsy using smart laser systems such as the rhodamine 6G dye laser and the FREDDY laser system can simplify the treatment of these difficult bile duct stones. The rhodamine 6G-dye laser allows blind fragmentation of these stones by exclusive insertion of a 7-F metal marked standard catheter into the bile duct by standard duodenoscopes using intermittent fluoroscopy. An oSTDS safely cuts off the laser pulse if contact with the stone is lost, thus preserving the bile duct from potential damage. Unfortunately the system is no longer produced. The new FREDDY laser lithotriptor with a piezoacoustic stone/tissue discrimination system offers an alternative to the rhodamine 6G dye laser system at less than half the financial investment. Effective stone fragmentation is accompanied by only low tissue alteration. The holmium:YAG laser is an effective multidisciplinary lithotriptor, but it can be used only under cholangioscopic control, limiting its use to gastroenterologic centers.

Pharmacokinetics of sulfamethoxazole and trimethoprim in donkeys, mules, and horses.

OBJECTIVE: To compare serum disposition of sulfamethoxazole and trimethoprim after IV administration to donkeys, mules, and horses. ANIMALS: 5 donkeys, 5 mules, and 3 horses. PROCEDURE: Blood samples were collected before (time 0) and 5, 15, 30, and 45 minutes and 1, 1.25, 1.5, 1.75, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 8, 10, and 24 hours after IV administration of sulfamethoxazole (12.5 mg/kg) and trimethoprim (2.5 mg/kg). Serum was analyzed in triplicate with high-performance liquid chromatography for determination of sulfamethoxazole and trimethoprim concentrations. Serum concentration-time curve for each animal was analyzed separately to estimate noncompartmental pharmacokinetic variables. RESULTS: Clearance of trimethoprim and sulfamethoxazole in donkeys was significantly faster than in mules or horses. In donkeys, mean residence time (MRT) of sulfamethoxazole (2.5 hours) was less than half the MRT in mules (6.2 hours); MRT of trimethoprim in donkeys (0.8 hours) was half that in horses (1.5 hours). Volume of distribution at steady state (Vdss) for sulfamethoxazole did not differ, but Vdss of trimethoprim was significantly greater in horses than mules or donkeys. Area under the curve for sulfamethoxazole and trimethoprim was higher in mules than in horses or donkeys. CONCLUSIONS AND CLINICAL RELEVANCE: Dosing intervals for IV administration of trimethoprim-sulfamethoxazole in horses may not be appropriate for use in donkeys or mules. Donkeys eliminate the drugs rapidly, compared with horses. Ratios of trimethoprim and sulfamethoxazole optimum for antibacterial activity are maintained for only a short duration in horses, donkeys, and mules.

A comparison of three combinations of injectable anesthetics in miniature donkeys.

OBJECTIVE: To compare three combinations of injectable anesthetics in miniature donkeys for quality of induction, recovery, muscle relaxation, cardiopulmonary changes during anesthesia and duration of recumbency. Design Prospective, randomized experimental study. ANIMALS: Six miniature donkeys (< 90 cm in height at the withers) weighing 92-127 kg were used. MATERIALS AND METHODS: The drug combinations were: xylazine-butorphanol-ketamine (XBK), xylazine-butorphanol-tiletamine-zolazepam (XBT) and xylazine-propofol (XP). Each miniature donkey was anesthetized with each combination at 1-week intervals in random order. Heart and respiratory rates, indirect blood pressure and temperature were measured before and at 5-minute intervals during recumbency. Arterial blood samples were drawn for blood-gas analysis before and at 5, 15 and 30 minutes of anesthesia when samples could be collected. Recumbency time to sternal and time to standing were recorded and a subjective evaluation of induction, muscle relaxation and recovery were made. RESULTS: Mean recumbency time ± SD was 14.7 ± 9.4, 33.8 ± 6.3 and 14.6 ± 1.9 minutes with XBK, XBT and XP, respectively. Mean time to standing ± SD was 28.4 ± 11.3, 43.7 ± 7.2 and 26.3 ± 2.9 minutes with XBK, XBT and XP, respectively. Heart and respiratory rates and blood pressures varied from baseline but were always within normal ranges. Hemoglobin saturation, pH and PaO2 tended to be lower with these doses of XBT and XP. CONCLUSIONS AND CLINICAL RELEVANCE: Overall quality of anesthesia was poor with XBK. At the doses used this combination did not provide sufficient anesthesia compared with the combinations of XBT and XP, which appeared to provide acceptable anesthesia of short duration in miniature donkeys.