Biomaterial Database

Use of flow-volume loops to evaluate upper airway obstruction in exercising standardbreds. 1993

J M Lumsden, and F J Derksen, and J A Stick, and N E Robinson

Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824-1314.

Flow-volume loops generated from 6 Standardbreds at rest and during treadmill exercise were evaluated for their use in detecting upper airway obstruction. Tidal breathing flow-volume loops (TBFVL) were obtained from horses at rest and exercising at speeds corresponding to 75% of maximal heart rate and at maximal heart rate. The TBFVL were evaluated, using a pulmonary function computer; calculated indices describing airflow rate and expiratory-to-inspiratory airflow ratio for individual loops were determined. In addition to TBFVL indices, standard variables of upper airway function also were measured: peak airflow, peak pressure, and calculated inspiratory and expiratory impedances. Measurements were recorded before left recurrent laryngeal neurectomy (LRLN; baseline) and 14 days after surgically induced left laryngeal hemiplegia. When horses were at rest, TBFVL shape and indices describing the loop were highly variable. In contrast, in exercising horses, TBFVL shape was consistent and coefficients of variation of loop indices were less during exercise than at rest. After LRLN, TBFVL from exercising horses indicated marked inspiratory airflow limitation, while the expiratory airflow curve was preserved. Peak inspiratory flow rate and inspiratory flow at 50 and 25% of tidal volume decreased, and the ratio of peak expiratory to inspiratory airflow and that of midtidal volume expiratory and inspiratory airflow rates increased significantly (P < 0.05). Inspiratory impedance also increased after LRLN. Although in resting horses TBFVL were not a useful indicator of upper airway obstruction, examination of TBFVL from exercising horses allowed objective, specific, and repeatable detection of upper airway obstruction. The technique was noninvasive, rapid, and well tolerated by horses; thus, it is a potentially valuable clinical diagnostic test.

UI	MeSH Term	Description	Entries
D007823	Laryngeal Nerves	Branches of the VAGUS NERVE. The superior laryngeal nerves originate near the nodose ganglion and separate into external branches, which supply motor fibers to the cricothyroid muscles, and internal branches, which carry sensory fibers. The RECURRENT LARYNGEAL NERVE originates more caudally and carries efferents to all muscles of the larynx except the cricothyroid. The laryngeal nerves and their various branches also carry sensory and autonomic fibers to the laryngeal, pharyngeal, tracheal, and cardiac regions.	Laryngeal Nerve, Superior,Laryngeal Nerve,Laryngeal Nerves, Superior,Nerve, Laryngeal,Nerve, Superior Laryngeal,Nerves, Laryngeal,Nerves, Superior Laryngeal,Superior Laryngeal Nerve,Superior Laryngeal Nerves
D008297	Male		Males
D009121	Muscle Denervation	The resection or removal of the innervation of a muscle or muscle tissue.	Denervation, Muscle,Denervations, Muscle,Muscle Denervations
D010366	Peak Expiratory Flow Rate	Measurement of the maximum rate of airflow attained during a FORCED VITAL CAPACITY determination. Common abbreviations are PEFR and PFR.	Expiratory Peak Flow Rate,Flow Rate, Peak Expiratory,PEFR
D010805	Physical Conditioning, Animal	Diet modification and physical exercise to improve the ability of animals to perform physical activities.	Animal Physical Conditioning,Animal Physical Conditionings,Conditioning, Animal Physical,Conditionings, Animal Physical,Physical Conditionings, Animal
D005260	Female		Females
D006339	Heart Rate	The number of times the HEART VENTRICLES contract per unit of time, usually per minute.	Cardiac Rate,Chronotropism, Cardiac,Heart Rate Control,Heartbeat,Pulse Rate,Cardiac Chronotropy,Cardiac Chronotropism,Cardiac Rates,Chronotropy, Cardiac,Control, Heart Rate,Heart Rates,Heartbeats,Pulse Rates,Rate Control, Heart,Rate, Cardiac,Rate, Heart,Rate, Pulse
D006736	Horses	Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.	Equus caballus,Equus przewalskii,Horse, Domestic,Domestic Horse,Domestic Horses,Horse,Horses, Domestic
D000402	Airway Obstruction	Any hindrance to the passage of air into and out of the lungs.	Choking,Airway Obstructions,Obstruction, Airway,Obstructions, Airway
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia