title: Canine awake head-out plethysmography (HOP): characterization of external resistive loading and spontaneous laryngeal paralysis.
abstract: We applied a novel head-out plethysmographic (HOP) method to study awake canine responses to external resistive loading and natural laryngeal paralysis. Measurements of inspiratory and expiratory specific airway resistance (sRaw(insp), sRaw(exp)) were obtained before and after uni- and bidirectional loading (R(add) = 5 cmH(2)O/L/s) in large-breed dogs (n = 9). Mean sRaw(insp) after inspiratory, and sRaw(exp) after expiratory loading were 31.4 and 33.3 cmH(2)Os, respectively. Bidirectional loads induced a significantly greater rise in both sRaw(insp) and sRaw(exp) (55.1 and 61.3 cmH(2)Os) compared to unidirectional loading (P < 0.001). Yet, type of loading did not affect flow-volume indices. The mean R(aw) of dogs was 4.81 cmH(2)O/L/s. Expiratory loading resulted in a significant 8.8% increase in functional-residual-capacity (FRC), compared to FRC(baseline) (76.7 ml/kg). Dogs (n = 5) with laryngeal paralysis demonstrated a significant increase in sR(aw) and R(aw) compared to controls without changes in FRC. In conclusion, HOP precisely characterized sR(aw) in response to external resistive loading. Hence, we could accurately quantify airway obstruction in awake dogs with laryngeal paralysis.
authors.affiliation: Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, 200 Westboro Rd., North Grafton, MA 01536, USA. Daniela.bedenice@tufts.edu
authors.forename: D
authors.initials: D
authors.lastname: Bedenice
authors.forename: E
authors.initials: E
authors.lastname: Rozanski
authors.forename: J
authors.initials: J
authors.lastname: Bach
authors.forename: J
authors.initials: J
authors.lastname: Lofgren
authors.forename: A M
authors.initials: AM
authors.lastname: Hoffman
mesh_terms: D000403:Airway Resistance / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D004285:Dogs; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D005652:Functional Residual Capacity; D006257:Head / Q000502:physiology*; D008297:Male; D010991:Plethysmography; D015656:Respiratory Mechanics / Q000502:physiology*; D014826:Vocal Cord Paralysis / Q000503:physiopathology*; D014851:Wakefulness / Q000502:physiology*