Effects of Bit Chewing on Right Upper Quadrant Intestinal Sound Frequency in Adult Horses

A new smartphone-based digital stethoscope featuring phonocardiography and electrocardiography in adult horses

Smartphone-based technology is increasingly used in veterinary medicine as a complementary tool for cardiac auscultation and ECG recording. This prospective observational study evaluates a digital stethoscope (DS) that consists of simultaneous phonocardiographic and one-lead ECG recording (dECG) in adult horses, comparing it with auscultation using a conventional stethoscope (CS) and reference base-apex ECG (rECG). A total of 104 horses underwent cardiac auscultation using CSs and DSs to detect arrhythmias and murmurs. Audio and dECG were acquired using the DS. The rECG tracings were also recorded. All ECG tracings were blindly evaluated for interpretability, measurements, and diagnosis. The Shapiro-Wilk test was used to assess the data distribution. Weighted Cohen's κ and Bland Altman plot analysis were applied to verify the agreement between reference vs. smartphone-based methods. Almost perfect agreement was found in detecting murmurs and/or arrhythmias between auscultation with the CS and DS, and between CS auscultation and re-listening to DS audio. Perfect agreement was observed between re-listening to DS audio and DS auscultation and in detecting murmur timing between CS and DS auscultation. Almost perfect agreement was found between rECG and dECG in detecting bradycardia, tachycardia, or normal heart rate (HR) and for P-wave polarity. The lack of variability with both methods for QRS polarity prevented statistical analyses from being performed. Fair agreement was found in the assessment of the presence of artifact. In conclusion, the DS reliably detected heart murmurs and arrhythmias through direct auscultation and re-listening to recordings, and accurately evaluated HR, wave and interval measurements, P-wave and QRS-complex polarities in adult horses.

Transcutaneous Auricular Vagal Nerve Stimulation in Healthy Non-Sedated Horses: A Feasibility Study

This study aimed to evaluate the feasibility of transcutaneous auricular vagal nerve stimulation (tAVNS) in healthy horses and its effect on heart rate variability (HRV). The study comprised three phases: the selection of mares, their acclimatization to the tAVNS, and the stimulation phase. Stimulation was performed with two electrodes positioned on the right pinna. The settings were 0.5 mA, 250 μs, and 25 Hz for pulse amplitude, pulse width, and pulse frequency, respectively. HRV was analysed before (B1), during (T), and after (B2) the tAVNS. From the 44 mares initially included, only 7 completed the three phases. In these mares, the heart rate (HR) was significantly lower, and frequency domain parameters showed an increased parasympathetic tone in B2 compared with B1. However, in 3/7 mares, the HR was significantly higher during T compared with B1 and B2, compatible with a decreased parasympathetic tone, while in 4/7 mares, the HR was significantly lower and the parasympathetic nervous system index was significantly higher during T and B2 compared with B1. The tAVNS is an economical and easy procedure to perform and has the potential to stimulate vagal activity; however, it was poorly tolerated in the mares included in this study.

Use of a new device for inversion of the necrotic ileal stump in the caecum in four horses

BACKGROUND

In jejunocaecal anastomosis leaving a necrotic ileal stump has been implicated in complications and poor outcomes. Elective inversion of the necrotic stump using a nasogastric tube has been previously described, although this procedure can be cumbersome and can cause caecocolic orifice occlusion.

OBJECTIVE

To describe the use of a new device for elective inversion of necrotic ileal stumps.

STUDY DESIGN

Case report.

METHODS

Details of the four horses that underwent intestinal resection and anastomosis with elective inversion of the ileal stump were retrieved from their medical records. For each case, a device was constructed by securing 0.7 m of hemp tape to a 0.5 m long electrical cable puller. The device was inserted into the ileum and passed through the caecum. The ileal lumen was closed using sutures or staples, and the tape was simultaneously secured to the intestine. The ileum was then resected. A small typhlotomy was performed at the proposed site for jejunocaecal anastomosis. The device was retrieved, the hemp tape was cut, and jejunocaecal anastomosis was completed.

RESULTS

The device was easily secured to the intestines. Small enterotomies were sufficient for device insertion and removal. In four clinical cases the procedure was effective in inverting the stump, and three out of the four horses recovered uneventfully and were discharged from the hospital. One horse was euthanised due to colic 27 months following discharge.

MAIN LIMITATIONS

Small number of cases admitted to single tertiary hospital.

CONCLUSIONS

The device was effective in inverting the ileal stump in the included clinical cases. By leaving a short, inverted stump, this method may help improve the prognosis for jejunocaecal anastomosis, possibly avoiding certain undesired effects of the procedure. Further studies with large numbers of cases are required.

Effects of Bit Chewing on Gastric Emptying, Small Intestinal Transit, and Orocecal Transit Times in Clinically Normal Horses

Ileus is a common life-threatening problem in horses, and currently available treatments may be ineffective. The purpose of this study was to determine whether bit chewing, a form of sham feeding, decreases the gastric emptying time (GET), small intestinal transit time (SITT), and total orocecal transit time (OCTT) in clinically normal horses in a prospective crossover study. Nine healthy horses were acclimated and fed a standardized diet. Following 24 h of fasting, self-contained video endoscopy capsules and acetaminophen were administered into the stomach via a nasogastric tube. Each horse underwent experimental (bit chewing for 20 min every 6 h) or control (no bit chewing) conditions, with a 3-week minimum washout period between conditions. The horses were enrolled in either part of the study until all video capsules were retrieved and/or 30 days lapsed. The video capsules were recovered from manure, and GET, SITT, and OCTT were determined from a video analysis. Bit chewing significantly decreased OCTT (p = 0.015) compared to the control conditions. Bit chewing decreased GET and SITT, but the differences were not significant. The mean (median) times determined via the video capsule analysis for the bit-chewing conditions were as follows: GET, 2.34 h (2.86 h); SITT, 3.22 h (3.65 h); and OCTT, 5.13 h (6.15 h), and for the control conditions, they were as follows: GET, 3.93 h (5 h); SITT, 3.79 h (4.4 h); and OCTT, 8.02 h (9.92 h). Bit chewing decreased OCTT in healthy horses. Because this segment of the gastrointestinal tract is frequently affected by ileus, bit chewing may be a safe and inexpensive intervention for that condition in horses. Further investigation in clinical patients with ileus is warranted.

The effects of bit chewing on borborygmi, duodenal motility, and gastrointestinal transit time in clinically normal horses

OBJECTIVE

To determine the influence of bit chewing on gastrointestinal transit in clinically normal horses.

STUDY DESIGN

Prospective crossover designed study.

ANIMALS

Six healthy adult horses.

METHODS

Horses were assigned randomly to treatment (apple flavored bit) and control (no-bit) groups and studied for 2 × 1-week trial periods with a 2-week washout period between trials. Horses were fasted for 24 h and slowly refed over 3 days. The bit was placed for 20 min every 6 h. Duodenal contractions and borborygmi auscultations were evaluated every 12 h, approximately 5 min following bit placement. Gastrointestinal total transit time (GI TTT) was measured by administering 200 colored beads via stomach tube and then collected in the manure until 50% and 80% were recovered. Measured variables were compared using an ANOVA or Wilcoxon signed-rank test and the P value was noted.

RESULTS

The GI TTT was shortened in the bit chewing group (median: 106.37 h, range: 70-171 h) compared to the no-bit group (median: 170.1 h, range: 149-186 h) (P = .0156) at 80% bead passage (only 4/6 horses passed 80%). Borborygmi (P = .8193), duodenal contractions (P = .2605), and 50% bead passage (P = .0781) showed no differences.

CONCLUSION

Bit chewing was safe, inexpensive, and well tolerated. Bit chewing shortened GI TTT and might be an adjunct therapy to augment GI TTT. Further clinical studies are warranted.

CLINICAL SIGNIFICANCE

Ileus is a common complication following equine abdominal surgery with no current consistently successful treatment. Bit chewing may be a simple and inexpensive way to augment progressive GI motility.