Comparison Study of Airway Reactivity Outcomes due to a Pharmacologic Challenge Test: Impulse Oscillometry versus Least Mean Squared Analysis Techniques

Abstract

The technique of measuring transpulmonary pressure and respiratory airflow with manometry and pneumotachography using the least mean squared analysis (LMS) has been used broadly in both preclinical and clinical settings for the evaluation of neonatal respiratory function during tidal volume breathing for lung tissue and airway frictional mechanical properties measurements. Whereas the technique of measuring respiratory function using the impulse oscillation technique (IOS) involves the assessment of the relationship between pressure and flow using an impulse signal with a range of frequencies, requires less cooperation and provides more information on total respiratory system resistance (chest wall, lung tissue, and airways). The present study represents a preclinical animal study to determine whether these respiratory function techniques (LMS and IOS) are comparable in detecting changes in respiratory resistance derived from a direct pharmacological challenge.

Solitary Cholinergic Stimulation Induces Airway Hyperreactivity and Transcription of Distinct Pro-inflammatory Pathways

“…When methacholine was co-delivered with a bronchodilator, the airway remodeling was prevented, suggesting that bronchoconstriction, and not the methacholine itself, was responsible for the airway remodeling. In our studies, we delivered a single dose of bethanechol that elicited bronchoconstriction [9]. Although we did not observe airway remodeling in our piglets, our findings are consistent with previous work suggesting that bronchoconstriction contributes to asthma pathology [27].…”

“…A laryngotracheal atomizer (MADgic) was passed directly beyond the vocal folds to aerosolize either a 500 µl of 0.9% saline control or 8 mg/ml bethanechol chloride (Selleckchem) in 0.9% saline solution to the airway. The dose selected has previously been shown to acutely increase airway resistance in piglets [9]. Of the total 16 piglets that underwent instillation, 6 piglets were simply observed and euthanized.…”

Airway cholinergic history modifies mucus secretion properties to subsequent cholinergic challenge in diminished chloride and bicarbonate conditions

“…The airways were accessed with a laryngoscope, and a laryngotracheal atomizer (MADgic, Moutainside Medical Equipment, Marcy, NY, USA) was passed directly beyond the vocal folds to aerosolize either 500 µl of bethanechol chloride in 0.9% saline solution or 0.9% saline solution alone (control) to the airway (Reznikov et al., 2018). The selected dose previously resulted in an acute increase in airway resistance in piglets (Reznikov et al., 2018; Rodriguez, Bullard, Armani, Miller, & Shaffer, 2013). Airway resistance is mediated by smooth muscle in the airways that is located deep to submucosal glands, which are a key target for mucus secretion in the present study.…”

Durable Changes to Airway Mucus and Fluid Secretion Following Cholinergic Challenge

“…Airways were accessed with a laryngoscope and a laryngotracheal atomizer (MADgic) was passed directly beyond the vocal folds to aerosolize either a 500 µl of 0.9% saline solution (control) or bethanechol chloride in 0.9% saline solution to the airway [16]. The dose selected has previously been shown to acutely increase airway resistance in piglets [16,17].…”