The relationship between peak expiratory sound intensity and peak expiratory flow rate in the thoroughbred horse during exercise.

Peak expiratory sound intensity (dB SPL), obtained by means of a radiostethoscope, and peak expiratory flow rate, obtained using a mask incorporating a thermistor flow sensor, were measured in six Thoroughbreds over a range of stride rates from 100 to 140 strides per min. The results show linear relationships between peak dB SPL and stride rate, peak expiratory flow rate and stride rate and also between peak expiratory flow rate and peak dB SPL. Peak expiratory dB SPL can therefore indicate peak expiratory flow rate.

Impedance plethysmography.

The technique of impedance plethysmography is described and its application to observation of lung volume changes in the horse at exercise is discussed. The results from horse at rest show that there is a close relationship between rate of lung volume change (flow rate) and the associated impedance changes during both inspiration and expiration. Impedance changes during exercise were related to inspiration and expiration by observation of associated respiratory sounds. Artefacts related to technical difficulties are also indicated.

Development of an equine nuclear medicine facility for gamma camera imaging.

A nuclear medicine facility constructed specifically for the application of a gamma camera system to the radioisotope imaging of bone, pulmonary circulation and ventilation in the horse is described. The gamma camera was previously used for human nuclear medicine, and a support for the gamma camera head was specifically designed for this work. Imaging protocols are suggested and the necessary materials for bone and lung studies are described. Images of bone and lung are shown and computer analysis of the data indicated. Imaging times are approximately 1 to 2 mins and typical bone and lung studies can be completed in 20 to 30 mins.