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The Prevalence of Abnormal Breathing Patterns During Exercise and Associations with Dynamic Upper Respiratory Tract Obstructions
Author(s) -
Fitzharris L,
Franklin S,
Allen K
Publication year - 2014
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12267_65
Subject(s) - medicine , ventilation (architecture) , treadmill , respiratory system , breathing , respiratory tract , cardiology , physical therapy , anesthesia , mechanical engineering , engineering
During canter and gallop most horses maintain a locomotor‐respiratory coupling ( LRC ) ratio of one breath every stride. Occasional big respiratory cycles ( BRC ) are described when a single breath is taken over two strides. This is considered a transient but normal feature of ventilation. However, a change to a more persistent 2:1 LRC ratio is considered to be ‘abnormal’. It has been suggested that upper respiratory tract ( URT ) disorders could result in a horse adopting an abnormal breathing pattern, although current information is limited. Methods Simultaneous audio and URT endoscopy recordings from 365 horses referred for treadmill evaluation were analysed. Breathing pattern at canter and gallop was categorised at each one minute speed step: Normal: 1:1 with <2 BRC Normal: 1:1 with 2 BRC Abnormal: breathing pattern disrupted by repetitive and frequent BRC's Abnormal: alternating between periods of 2:1 and 1:1 Abnormal: 2:1 throughout Data analysis was performed using PASW 18.0. A chi‐square test was used to identify associations between breathing pattern and presence of URT obstructions. Results During the entire exercise test 30% of horses had an abnormal breathing pattern at canter or gallop, of which 23% had a 2:1 breathing pattern. The prevalence of abnormal breathing patterns was higher at low canter speeds than during strenuous exercise. There was a significant association between breathing pattern during strenuous exercise and the presence of an URT obstruction (P = 0.008). Conclusions Loss of a 1:1 LRC ratio during canter and gallop is more common than previously realised and may be associated with dynamic URT obstructions. Ethical Animal Research Retrospective analysis of case records. Sources of funding: none declared. Competing interests: none.