Wheatley, Courtney M.

Background: The Vibralung Acoustical Percussor is a new airway clearance therapy (ACT) utilizing intrapulmonary sound waves in addition to positive expiratory pressure (PEP). We evaluated the safety of the Vibralung and collected preliminary data on its ability to mediate sputum expectoration in individuals with cystic fibrosis (CF). Methods: Over two separate studies, 10 and 11 mild to moderate CF patients were recruited for study I and II, respectively. Study I: Vibralung was used for 20 min with either no sound (NS: PEP only) or sound (S: PEP and sound) on randomized visits. Pulmonary function, diffusion capacity of the lungs for carbon monoxide and nitric oxide (DLCO/DLNO), symptoms, and peripheral oxygen saturation (SpO2) were measured at baseline and at 1 and 4 h post treatment. Expectorated sputum was collected over 4 h post treatment. Study II: over 5 days of in-hospital therapy, the Vibralung or vibratory vest therapy (Vest) were used for two therapy sessions per day, with sputum collected for 20 min following each therapy and pulmonary function accessed pre and post each 5-day period (days 1–5 or 7–11) in a randomized crossover design. Results: Vibralung usage resulted in no change from baseline to 4 h post in pulmonary function, SpO2 or symptoms ( p > 0.05). At 4 h post therapy, the DLCO- and DLNO-derived measure of alveolar–capillary unit function (DM/ VC) showed improvement (DM/ VC = 12.5 ± 5.5 versus 7.3 ± 18.8% change, S versus NS) with no difference between S and NS ( p = 0.74). Sputum expectoration was similar between S and NS conditions (wet sputum = 10.5 ± 4.6 versus 9.9 ± 3.2 g, S versus NS, p = 0.25). There were no differences in the improvement in pulmonary function between Vibralung and Vest during either 5-day period during the hospital stay. Conclusions: Vibralung was well tolerated and caused no detrimental changes in pulmonary function metrics. The Vibralung appears to be a safe ACT in individuals with CF.

Abstract Aims The effect of extravascular lung water (EVLW) and relationship to functional status as a result of acute decompensated heart failure (ADHF) are not well understood. We sought to quantify changes in clinical variables, EVLW, airway anatomy, spirometry, and diffusing capacity for carbon monoxide before and after treatment for ADHF. Methods and results Fifteen patients were recruited within 24 h of hospital admission. Spirometry, diffusing capacity for carbon monoxide, and surrogates of EVLW by computed tomography were measured and were then repeated within 24 h of discharge. From the computed tomography (CT) scan, surrogates of EVLW were calculated from the distribution of CT attenuation of the lung tissue. Airways were segmented using the Vida Apollo software. Patients were hospitalized for 4.6 ± 2.1 days, had 10 ± 4.8 L of fluid removed (7.0 ± 4.2 L between study visits), and lost 7.1 ± 4.9 kg. Patients had significant clearance of fluid from the lungs (per cent change: mean, 4.2 ± 6.1%; skew, 17.5 ± 27.0%; kurtosis, 37.6 ± 56.7%; full-width half-maximum, 10.2 ± 13.5%). Static lung volumes and maximal flows improved significantly (per cent change: forced vital capacity, 14.5 ± 13.6%; forced expiratory volume in 1 s, 15.9 ± 14.0%; forced expiratory flow at 25–75% of forced vital capacity, 27.2 ± 42.9%). The ratio of membrane conductance to capillary blood volume improved significantly (per cent change: alveolar–capillary membrane conductance/capillary blood volume, 23.4 ± 22.8%). Weight loss during hospitalization was significantly correlated with improved spirometry and diffusing capacity. Conclusions Extravascular lung water contributes to the pulmonary congestive syndrome in ADHF patients, and its clearance is an important component of the improvement in pulmonary function as a result of inpatient treatment.

Cardiac output (CO) assessment as a basic hemodynamic parameter has been of interest in exercise physiology, cardiology, and anesthesiology. Noninvasive techniques available are technically challenging, and thus difficult to use outside of a clinical or laboratory setting. We propose a novel method of noninvasive CO assessment using a single, upper-arm cuff. The method uses the arterial pressure pulse wave signal acquired from the brachial artery during 20-s intervals of suprasystolic occlusion. This method was evaluated in a cohort of 12 healthy individuals (age, 27.7 ± 5.4 yr, 50% men) and compared with an established method for noninvasive CO assessment, the open-circuit acetylene method (OpCirc) at rest, and during low- to moderate-intensity exercise. CO increased from rest to exercise (rest, 7.4 ± 0.8 vs. 7.2 ± 0.8; low, 9.8 ± 1.8 vs. 9.9 ± 2.0; moderate, 14.1 ± 2.8 vs. 14.8 ± 3.2 l/min) as assessed by the cuff-occlusion and OpCirc techniques, respectively. The average error of experimental technique compared with OpCirc was −0.25 ± 1.02 l/min, Pearson’s correlation coefficient of 0.96 (rest + exercise), and 0.21 ± 0.42 l/min with Pearson’s correlation coefficient of 0.87 (rest only). Bland-Altman analysis demonstrated good agreement between methods (within 95% boundaries); the reproducibility coefficient (RPC) = 0.84 l/min with R2= 0.75 at rest and RPC = 2 l/min with R2= 0.92 at rest and during exercise, respectively. In comparison with an established method to quantify CO, the cuff-occlusion method provides similar measures at rest and with light to moderate exercise. Thus, we believe this method has the potential to be used as a new, noninvasive method for assessing CO during exercise.

Blood pressure (BP) is a key measure of cardiovascular function, and accurate measurement is important to ensure proper clinical evaluation, diagnosis, and treatment. We compared intra-arterial (direct) and cuff auscultation (manual) measurement techniques at rest and during 2 levels of submaximal constant-load exercise (9 min at 40% and 75% maximum watts). Sixty-four adults (aged 29.0 ± 0.7 years; 48% male; height, 173.7 ± 1.2 cm; mass, 73.0 ± 1.7 kg; body mass index, 24.1 ± 0.4 kg·m−2; body surface area, 1.87 ± 0.03 m2) participated in the study. At rest, low, and moderate intensity, direct measurement demonstrated higher systolic BP (SBP) and diastolic BP (DBP) (bias for SBP: 22, 31, and 27 mm Hg and for DBP: 5, 7, and 17 mm Hg; rest, low-, and moderate-intensity, respectively; p < 0.01). At rest, the correlation and agreement between the 2 methods was modest (SBP: r = 0.56, bias = +22.1 mm Hg; DBP: r = 0.53, bias = +4.9 mm Hg; p < 0.001). There was good correlation and agreement with SBP at low and moderate intensity; however, DBP demonstrated a weaker relationship (SBP: r = 0.74 and 0.74, bias = +30.2 and +26.8 mm Hg; DBP: r = 0.39 and 0.28, bias = +7.1 and +13.4 mm Hg; for low and moderate intensity, respectively; p < 0.001). Further, manual measurement demonstrated a greater slope from rest to moderate exercise for the relationship between pulse pressure (PP) and cardiac output (13.6 ± 0.4 vs 12.3 ± 0.4, p = 0.03). As exercise intensity increases, manual DBP tends to bias low compared with direct DBP, which, when combined with parallel increases in SBP, leads to no differences in PP between methods at moderate exercise. Because PP is used to calculate other cardiovascular parameters (mean arterial pressure, systemic vascular resistance), measurement technique and exercise intensity should be considered when using cardiovascular variables as outcome measures.