Objective—To determine the effects of hypoglossal nerve block and electrical stimulation of the thyrohyoideus muscles on position of the larynx and hyoid apparatus in resting horses.
Animals—16 healthy horses that underwent hypoglossal nerve block and 5 healthy horses that underwent electrical stimulation of the thyrohyoideus muscles.
Procedures—Horses underwent bilateral hypoglossal nerve block or electrical stimulation of the thyrohyoideus muscles. Positions of the basihyoid bone, ossified part of the thyroid cartilage, and articulations of the thyrohyoid bones and thyroid cartilage were determined in radiographic images obtained before and after performance of hypoglossal nerve blocks or during thyrohyoideus muscle stimulation. Radiographic images were obtained with the heads of horses in neutral (thyrohyoideus muscle stimulation) or neutral and extended (hypoglossal nerve block) positions. Radiographic images of horses obtained after performance of hypoglossal nerve blocks were also evaluated to detect dorsal displacement of the soft palate.
Results—Hypoglossal nerve blocks did not induce significant changes in the positions of evaluated anatomic sites in radiographic images obtained in neutral or extended head positions. Hypoglossal nerve block did not induce dorsal displacement of the soft palate in horses at rest. Bilateral thyrohyoideus muscle stimulation induced significant dorsal movement (mean ± SD change in position, 18.7 ± 6.8 mm) of the ossified part of the thyroid cartilage; rostral movement of evaluated anatomic structures was small and not significant after thyrohyoideus muscle stimulation.
Conclusions and Clinical Relevance—Bilateral electrical stimulation of the thyrohyoideus muscles in horses in this study induced dorsal laryngeal movement.
Objective—To compare postoperative complications,
short- and long-term survival, and surgical times for
hand-sewn end-to-end (EE), stapled functional end-toend
(FEE), and stapled side-to-side (SS) anastomotic
techniques for jejunal resection in horses.
Procedure—Medical records were reviewed to
obtain signalment, diagnosis, treatment, and outcome
for horses that underwent jejunojejunostomy in
our hospital. Only horses that recovered from anesthesia
were included in the study.
Results—Among the 59 horses, there were 33 EE,
15 FEE, and 11 SS anastomoses. No difference was
found in duration of surgery among the 3 techniques.
The most common postoperative complications
were colic episodes (56%), ileus (53%), diarrhea
(20%), and adhesions (15%). Horses with SS anastomosis
had a significantly shorter duration of postoperative
ileus than the EE group did. No significant
difference in duration of postoperative ileus was
found among the other groups. No difference was
found among the 3 anastomotic techniques in regard
to survival rate at the time of discharge, 6 months
after surgery, or 1 year after surgery. Overall survival
rates after jejunal anastomosis were 88% at the time
of discharge, 65% at 6 months after surgery, and
57% at ≥ 1 year after surgery.
Conclusions and Clinical Relevance—The handsewn
EE, stapled FEE, and stapled SS anastomotic
techniques should be considered equivalent methods
for small intestinal anastomosis in the horse.
However, the stapled SS technique may be preferred
because of possible decreased duration of postoperative
ileus. (J Am Vet Med Assoc 2002;220:215–218)
Objective—To investigate whether upper airway
sounds of horses exercising with laryngeal hemiplegia
and alar fold paralysis have distinct sound characteristics,
compared with unaffected horses.
Animals—6 mature horses.
Procedure—Upper airway sounds were recorded in
horses exercising on a high-speed treadmill at maximum
heart rate (HRMAX) under 3 treatment conditions
(ie, normal upper airway function [control condition],
and after induction of left laryngeal hemiplegia or bilateral
alar fold paralysis) in a randomized crossover
design. Fundamental frequency, spectrograms using
Gabor transform, and intensity characteristics of
acquired sounds (peak sound level [soundpeak] and
highest frequency of at least –25 dB sound intensity
[F25max]) were evaluated.
Results—Evaluation of the fundamental frequency of
the time domain signal was not useful. Sensitivity and
specificity (83 and 75%, respectively) of spectrograms
were greatest at maximal exercise, but the
exact abnormal condition was identified in evaluation
of only 12 of 18 spectrograms. Increased accuracy
was obtained using soundpeak and F25max as discriminating
variables. The use of soundpeak discriminated
between control and laryngeal hemiplegia conditions
and F25max between laryngeal hemiplegia and alar fold
paralysis conditions. This increased the specificity of
sound analysis to 92% (sensitivity 83%) and accurately
classified the abnormal state in 92% of affected
Conclusions and Clinical Relevance—Sound analysis
might be a useful adjunct to the diagnosis and evaluation
of treatment of horses with upper airway obstruction,
but would appear to require close attention to
exercise intensity. Multiple measurements of recorded
sounds might be needed to obtain sufficient accuracy
for clinical use. (Am J Vet Res 2002;63:1707–1713)
Objective—To determine the phase and quantitate the electromyographic (EMG) activity of the genioglossus, geniohyoideus, hyoepiglotticus, omohyoideus, sternohyoideus, sternothyroideus, and thyrohyoideus muscles of clinically normal horses during strenuous exercise.
Animals—7 clinically normal adult horses (2 Thoroughbreds and 5 Standardbreds).
Procedures—Bipolar electrodes were surgically implanted in the aforementioned muscles, and horses were subjected to an incremental exercise test on a high-speed treadmill. The EMG, heart rate, respiratory rate, and static pharyngeal airway pressures were measured during exercise. The EMG was measured as mean electrical activity (MEA). The MEA values for maximal exercise intensity (13 or 14 m/s) were expressed as a percentage of the MEA measured at an exercise intensity of 6 m/s.
Results—MEA was detected during expiration in the genioglossus, geniohyoideus, sternohyoideus, and thyrohyoideus muscles and during inspiration in the hyoepiglotticus and sternothyroideus muscles. Intensity of the MEA increased significantly with exercise intensity in the genioglossus, geniohyoideus, and hyoepiglotticus muscles. Intensity of the MEA increased significantly in relation to expiratory pharyngeal pressure in the geniohyoideus and hyoepiglotticus muscles.
Conclusions and Clinical Relevance—Once exercise intensity reached 6 m/s, no quantifiable additional increase in muscular activity was detected in the omohyoideus, sternohyoideus, sternothyroideus, and thyrohyoideus muscles. However, muscles that may affect the diameter of the oropharynx (genioglossus and geniohyoideus muscles) or rima glottis (hyoepiglotticus muscle) had activity correlated with the intensity of exercise or expiratory pharyngeal pressures. Activity of the muscles affecting the geometry of the oropharynx may be important in the pathophysiologic processes associated with nasopharyngeal patency.
A 10-month-old 488-kg (1,074-lb) Brown Swiss bull that was intended for use as a breeding animal was admitted to the Cornell University College of Veterinary Medicine Farm Animal Hospital and examined because of severe swelling of the prepuce and ventral abdomen as well as straining to urinate. Four weeks before admission, the bull had attempted to jump over a fence but became suspended on the wire; there was blunt trauma to the prepuce and caudal portion of the ventral abdomen. Initially, swelling in the injured region was moderate and the bull was able to urinate normally. Treatment of the
Objective—To compare cardiac troponin I (cTnI) concentrations determined by use of a point-of-care analyzer with values determined by use of a bench-top immunoassay in plasma samples obtained from clinically normal horses with and without experimentally induced cardiac disease, and to establish a reference range for plasma equine cTnI concentration determined by use of the point-of-care analyzer.
Animals—83 clinically normal horses, 6 of which were administered monensin to induce cardiac disease.
Procedures—A blood sample was collected from each of the 83 clinically normal horses to provide plasma for analysis by use of the point-of-care analyzer; some of the same samples were also analyzed by use of the immunoassay. All 83 samples were used to establish an analyzer-specific reference range for plasma cTnI concentration in clinically normal horses. In 6 horses, blood samples were also collected at various time points after administration of a single dose of monensin (1.0 to 1.5 mg/kg) via nasogastric intubation; plasma cTnI concentration in those samples was assessed by use of both methods.
Results—The analyzer-specific reference range for plasma cTnI concentration in clinically normal horses was 0.0 to 0.06 ng/mL. Following monensin treatment in 5 horses, increases in plasma cTnI concentration determined by use of the 2 methods were highly correlated (Pearson correlation, 0.83). Peak analyzer-determined plasma cTnI concentrations in monensin-treated horses ranged from 0.08 to 3.68 ng/mL.
Conclusions and Clinical Relevance—In horses with and without experimentally induced cardiac disease, the point-of-care analyzer and bench-top immunoassay provided similar values of plasma cTnI concentration.