Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction

Abstract

Ratios of VD(Bohr) to VT and VD(phys) to VT as well as an index of effective CO2 elimination were sufficiently sensitive measures to distinguish between healthy horses and horses with RAO in remission. To optimize the ability of volumetric capnography indices to differentiate among horses in heterogeneous populations, it is important to account for effects of age and specific use of the horses.

Relationship of horse owner assessed respiratory signs index to characteristics of recurrent airway obstruction in two Warmblood families

“…This is in accordance with other reports demonstrating incomplete reversibility of lung function deficits (e.g. Herholz et al. 2003).…”

Heaves, an asthma‐like disease of horses

“…The decrease in dynamic compliance is less consistently responsive to bronchodilator administration, possibly because of peripheral airways obstruction, uneven distribution of ventilation and parenchymal remodelling 7,8 . Abnormal ventilation distribution has been shown by nitrogen washout, 88 helium‐dilution measurements, 89 radiolabelled aerosolized technetium 90 and, indirectly, by volumetric capnography 91 . Ventilation/perfusion (V/Q) mismatch has also been shown to be most important during episodes of clinical exacerbation and to improve without disappearing following treatment 92,93 .…”

“…Whole body plethysmography is another non‐invasive technique that has been used to evaluate function and response to therapy, 104 but inherent technical difficulties have limited its use. Volumetric capnography and inductance plethysmography portability may prove helpful for the assessment of airway function in field studies 91,105 …”

Clinical application of continuous spirometry during equine anaesthesia and in spontaneous breathing, awake horses

“…Ultrasonic spirometry has been combined with capnography to perform the single breath analysis of CO 2 (volumetric capnography). This allowed the detection of airway obstruction in the standing, spontaneously breathing horse (Herholz et al . 2002b; and ).…”

“…Ultrasonic spirometry offers a simple, noninvasive, effort independent, economical and sensitive method for pulmonary function testing in the awake, spontaneously breathing horse (Herholz et al . 2001a,b,c,d,e; 2002a,b,c,d).…”