Pulmonary ventilation

Since 1956, the pMDI has become the most commonly prescribed and used aerosol device in the world. While concerns about global warming have led to a worldwide ban of CFCs, new HFA-propelled pMDIs are in development, requiring an evolutionary transition in the technology. The phase-out of CFC-propelled pMDIs has stimulated the development of more efficient DPIs, but issues such as cost of device production, inspiratory flow requirement, and the effects of ambient humidity on drug delivery may limit DPI acceptance, and industry projections suggest that the DPI will not completely replace the pMDI. Holding chambers may perform differently with HFA-propelled pMDIs, but HFA-propelled pMDIs generally appear to cause less oropharyngeal deposition and to improve lung delivery while continuing to provide protection from poor hand-breath coordination. The initial offerings of the emerging HFA-propelled pMDI technology appear to be resulting in an improved pMDI.

Summary: An important clinical issue concerns the efficacy of current voice therapy approaches in treating voice disorders, such as vocal nodules. Much research focuses on finding reliable methods for documentation of treatment results. In this second treatment study of ten patients with vocal nodules, who participated in a behaviorally based voice therapy program, 11 aerodynamic (transglottal air pressure and glottal waveform) and acoustic (spl, f0, and spectrum slope) measures were used. Three pretherapy baseline assessments were carried out, followed by one assessment after each of five therapy phases. Measurements were made of two types of speech materials: Strings of repeated /pae/ syllables and sustained /ae/ phonations in two loudness conditions: comfortable loudness and loud voice. The data were normalized using z-scores, which were based on data from 22 normal subjects. The results showed that the aerodynamic measures reflected the presence of vocal pathology to a higher degree than did the acoustic spectral measures, and they should be useful in studies comparing nodule and normal voice production. Large individual session-to-session variation was found for all measures across pretherapy baseline recordings, which contributed to nonsignificant differences between baseline and therapy data.

This study was designed to quantify the daily distribution of training intensity in a group of professional soccer players in Norway based on three different methods of training intensity quantification. Fifteen male athletes (age, 24 ± 5 y) performed treadmill test to exhaustion to determine heart rate and VO2 corresponding to ventilatory thresholds (VT1, VT2), maximal oxygen consumption (VO2max) and maximal heart rate. VT1 and VT2 were used to delineate three intensity zones based on heart rate. During a 4 wk period in the preseason (N = 15), and two separate weeks late in the season (N = 11), all endurance and on-ball training sessions (preseason: N = 378, season: N= 78) were quantified using continuous heart rate registration and session rating of perceived exertion (sRPE). Three different methods were used to quantify the intensity distribution: time in zone, session goal and sRPE. Intensity distributions across all sessions were similar when based on session goal or by sRPE. H...

Patient-ventilator synchrony and patient comfort are assumed to go hand in hand, yet few studies provide support for this common sense idea. In reality, synchrony between the patient and ventilator is complex and can be affected by the ventilator settings, type of ventilator, patient-ventilator interface, and sedation. Inspections of airway pressure and flow waveforms are reliable methods for detecting asynchrony, and automated detection seems accurate. A number of types of asynchronies have been defined, and asynchrony during invasive and noninvasive ventilation have different calling cards. There is a clear association between asynchrony, ventilator-induced diaphragmatic dysfunction, and duration of mechanical ventilation. Whether these are cause and effect or simply associated remains to be determined.

Objective: The impact of meditation on cardiorespiratory synchronization with respect to breathing oscillations and the modulations of heart rate induced by respiration (respiratory sinus arrhythmia, RSA) was investigated in this study. Methods: In a pilot study four different exercises (spontaneous breathing, mental task and two different types of meditation) were consecutively performed by 3 subjects (1 experienced, 2 unexperienced meditators). An electrocardiogram and a respiratory trace were recorded simultaneously. On this basis the degree of synchronization was quantified by a technique which has been adopted from the analysis of weakly coupled chaotic oscillators. Results: Both types of meditation showed a high degree of synchronization whereas heartbeat and respiration were hardly synchronized during spontaneous breathing. During the mental task exercise the extent of synchronization was slightly higher than during spontaneous breathing. These results were determined by the breathing frequency because the two types of meditation make use of low breathing frequencies which led to a pronounced and in-phase RSA. Heart rate, breathing frequency and the extent of RSA, i.e. heart rate variability, during the different exercises were less consistent because they reflected more individual characteristics of the autonomic control. Conclusion: Meditation synchronizes heart rate and respiration to a large extent. The high degree of synchronization during meditation in unexperienced meditators suggests that the physiological implications of meditation does not require prior experience in meditation.

This study aimed to assess the accuracy of the Cosmed K4b2 (Cosmed, Italy) portable metabolic system that measures FEO2, FECO2 and V̇E on a breath by breath basis. For gas concentration comparisons, expired air from 20 subjects performing treadmill running was collected in a 600 litre chain compensated Collins Tissot tank and analysed for FEO2 and FECO2 using a laboratory metabolic cart and the Cosmed K4 b2 metabolic system. For ventilation comparisons, serial steady state V̇E (STPD) values were measured on 10 subjects using the Cosmed K4b2 ventilation turbine and a Morgan ventilation monitor during a continuous treadmill running protocol at ascending speeds of 8, 11 and 14 km·h−1. The Cosmed K4b2 FEO2 and FECO2 measures were significantly lower (P<0.001) than the metabolic cart values. Pearson correlation coefficients (r) and the standard error of measurement (SEM) demonstrated a high association between the Cosmed and the metabolic cart measures (FEO2r= 0.971, SEM 0.071; FECO2r= 0.925, SEM 0.087). Cosmed V̇E (l·min−1 measures were significantly greater than Morgan values at running speeds of 8 km·h−1 (P<0.001) and 11 km·h−1 (P<0.001) but not significantly different at 14 km·h−1 (P>0.05). When V̇E measures at the three running speeds were combined, the mean difference between instrument measures ranged between 3.5 – 4.0 1·min−1 but the values were highly correlated (r= 0.982, P<0.01; SEM 3.03). Linear regression analysis revealed the following regression equations to predict metabolic cart values from Cosmed measures: FEO2= 0.852+0.963 Cosmed (R2= 0.940, P<0.001), FECO2= 0.627+0.878 Cosmed (R2= 0.856, P<0.001), V̇E= −2.50+0.984 Cosmed (R2= 0.965, P<0.001). The results indicated that the Cosmed K4b2 unit assessed here produced measures of FEO2, FECO2 and V̇E that had strong correlation to values obtained from a metabolic cart. However, linear regression analysis may further improve the accuracy of Cosmed K4b2 measures when compared to metabolic cart values.