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Evaluation of partial arytenoidectomy as a treatment for equine laryngeal hemiplegia
Author(s) -
LUMSDEN J. M.,
DERKSEN F. J.,
STICK J. A.,
ROBINSON N. E.,
NICKELS F. A.
Publication year - 1994
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/j.2042-3306.1994.tb04350.x
Subject(s) - medicine , tidal volume , anesthesia , heart rate , respiratory rate , respiratory system , cardiology , blood pressure
Summary The efficacy of partial arytenoidectomy was assessed in 6 Standardbred horses, with surgically induced laryngeal hemiplegia, at rest (Period A) and during exercise at speeds corresponding to maximum heart rate (Period C) and 75% of maximum heart rate (Period B). Peak expiratory and inspiratory airflow rate (PEF and PIF), and expiratory and inspiratory transupper airway pressure (P UE and P UI ) were measured and expiratory and inspiratory impedance (Z E and Z I ) were calculated. Simultaneously, tidal breathing flow‐volume loops (TBFVL) were acquired using a respiratory function computer. Indices derived from TBFVL included airflow rates at 50 and 25% of tidal volume (EF 50 , IF 50 , EF 25 . and IF 25 ) and the ratios of expiratory to inspiratory flows. Measurements were made before left recurrent laryngeal neurectomy (baseline), 2 weeks after left recurrent laryngeal neurectomy (LRLN) and 16 weeks after left partial arytenoidectomy coupled with bilateral ventriculectomy (ARYT). After LRLN, during exercise Periods B and C, Z 1 and the ratio of EF 50 /IF 50 significantly increased and PIF, IF 50 and IF 25 significantly decreased from baseline values. At 16 weeks after ARYT, Z 1 returned to baseline values during Periods B and C. Although PIF, IF 50 , IF 25 , PEF/PIF, and EF 50 /IF 50 returned to baseline values during Period B, these indices remained significantly different from baseline measurements during Period C. After ARYT, TBFVL shapes from horses during Period C approached that seen at the baseline evaluation. Partial arytenoidectomy improved upper airway function in exercising horses with surgically induced left laryngeal hemiplegia, although qualitative and quantitative evaluation of TBFVLs suggested that some flow limitation remains at near maximal airflow rates. These results indicate that, although the procedure does not completely restore the upper airway to normal, partial arytenoidectomy is a viable treatment option for failed laryngoplasty and arytenoid chondropathy in the horse.