Publications by authors named "Douglas Clark Johnson"
Spirometry Reference Equations Including Existing and Novel Parameters.
Open Respir Med J
February 2023
Introduction: Spirometry is an essential component of pulmonary function testing, with interpretation dependent upon comparing results to normal. Reference equations for mean and lower limit of normal (LLN) are available for usual parameters, including forced vital capacity (FVC), forced expiratory volume in the first second of an FVC maneuver (FEV1), and FEV1/FVC. However, standard parameters do not fully characterize the flow-volume loop and equations are unavailable for the upper limit of normal (ULN).
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- The study aimed to analyze the differences in demographics (sex, age, BMI) and health conditions (comorbidities) among sleep clinic patients with mild obstructive sleep-disordered breathing using different apnea-hypopnea index (AHI) criteria.
- A cohort of 305 adult patients was examined for polysomnography results, with significant findings regarding AHI rates, positive airway pressure adherence, and health issues prevalent in these patients.
- Results indicated that women had higher rates of various comorbidities like obesity and depression, while men showed higher adherence to positive airway pressure therapy; overall, there were notable differences in sleep quality and apnea/hypopnea durations based on sex, age, and BMI.
Objective: Apnea/hypopnea index (AHI), especially without arousal criteria, does not adequately risk stratify patients with mild obstructive sleep apnea (OSA). We describe and test scoring reliability of an event, Flow Limitation/Obstruction With recovery breath (FLOW), representing obstructive airflow disruptions using only pressure transducer and snore signals available without electroencephalography.
Methods: The following process was used (i) Development of FLOW event definition, (ii) Training period and definition refinement, and (iii) Reliability testing on 10 100-epoch polysomnography (PSG) samples and two 100-sample tests.
Treatment of sleep-disordered breathing with positive airway pressure devices: technology update.
Med Devices (Auckl)
November 2015
Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners.
View Article and Find Full Text PDFIntroduction: Readiness to speak is a major problem for many tracheostomized patients. Evaluation for tracheostomy tube capping or speaking valve is often subjective.
Objectives: We first wanted to assess whether there were differences among speaking valves.