Double Body Plethysmography (DBP), which combines total body plethysmography and opto-electronic Plethysmography, has been recently developed to measure the amount of blood displaced from the thorax to the extremities (Aliverti et al, PLoS One. 2009). By using DBP, we have recently shown that significant blood shifts (BS) occur during expulsive maneuvers and that abdominal pressure controls the outflow of blood from the splanchnic vasculature (Aliverti et al, J Appl Physiol, 2010). We hypothesized that also during cough a significant amount of blood can be displaced from the trunk to the extremities. We studied 7 healthy subjects (age: 28.6±2.5 yrs) during series of voluntary coughs at four different operating volumes: functional residual capacity (FRC), total lung capacity (TLC) and two intermediate volumes between FRC and TLC (namely, FRC+ and FRC++). BS from the thorax to the extremities were measured by DBP during quiet breathing and during cough at each operating lung volume. The results are shown in figure. BS during cough resulted significantly higher than during QB (p These findings might help to better understand the cardiopulmonary interactions during cough and the mechanism by which coughing during asystolic cardiac arrest can maintain consciousness in human subjects.

Introduction: Lung density and SVg variations between different lung volumes are reliable estimates of regional lung emptying/filling (Salito et al,Radiology,2009). Here the gravity-dependent regional differences occurring within the lung in both health (H) and emphysema (E) is evaluated. Methods: 10 healthy volunteers and 10 subjects with severe emphysema (FEV1 RV -HU TLC ) and SVg (ΔSVg=SVg TLC -SVg RV ) and resumed as mean differences in ventral, central and dorsal regions. Results: H showed significant ventro-dorsal differences: in left lung, ΔHU mean increased from 146.4±4.7 (ventral) to 180.8±20.8 (dorsal) (p=0.012) at AA, from 136.6±4.2 to 196.2±24.1 (p Conclusions: a) ΔHU is gravity-dependent in H but not in E; b) Healthy ΔHU gravity-dependence is higher at TD compared to more apical levels; c) ΔSVg is not gravity influenced and therefore a more reliable measure of regional lung emptying/filling.

Introduction: Variation of specific gas volume (SVg) between high and low lung volume is a reliable estimate of regional lung filling/emptying (Salito et al,Radiology,2009). The aim of this study was to evaluate how these variations are distributed in different regions of the lung in healthy and COPD subjects. Methods: 10 healthy volunteers and 10 subjects with severe emphysema (FEV1 TLC -SVg RV ) were calculated. Frequency distribution plots of ΔSVg at the different levels were then expressed in terms of mean, median, standard deviation and skewness. Results: Table 1 reports the pertinent values of the frequency distribution of ΔSVg in healthy and COPD subjects for each tracheo-bronchial tree level. Conclusions: In severe emphysema ΔSVg is smaller at any lung level, suggesting that alveolar destruction and gas trapping are homogeneously distributed within the lung. Regional distribution of SVg in emphysema presents an high degree of heterogeneity respect to healthy.

This review examines 18 studies published >= 30 yrs ago. They show that the earliest manifestation of chronic obstructive pulmonary disease (COPD) is an increase in residual volume suggesting that the natural history of COPD is a progressive increase in gas trapping with a decreasing vital capacity (VC). The reduction in VC forces the forced expiratory volume in 1 s to decline with it. This is aggravated by rapid shallow breathing leading to dynamic hyperinflation. The earlier studies show that this is energetically opposite to a minimal work or force pattern and is responsible for dyspnoea and exercise limitation.This information, available for >30 yrs leads to three virtually untested hypotheses: 1) training patients to breathe slowly and deeply transiently during exercise should decrease the work of breathing, dynamic hyperinflation and improve exercise performance; 2) rapid shallow breathing is caused by alveolar and bronchial inflammation that stimulates non-myelinated vagal C-fibre afferents, which are known to cause this breathing pattern; and 3) if so, therapeutic efforts to block these afferents might restore a slow-deep pattern and be beneficial, particularly in COPD exacerbations.

In order to produce sound on a wind instrument, the respiratory system and muscles contract or relax to create the required pressure, flow and velocity for each instrument (Bouhuys, 1977, Brown, 1990). In the case of low pressure instruments, researchers agree that some inspiratory muscles are recruited as antagonists during the expiratory phase (Bouhuys, 1977, Roos, 1936). Only few studies actually measured the respiratory muscle recruitment during wind instrument playing (Berger, 1968, Cossette et al. 2000, 2008). The authors' study (2008) reported that flute 'breath support', which is associated with high quality playing, entails antagonistic contraction of non-diaphragmatic inspiratory muscles. The rib cage is held at higher lung volume during long legato phrase playing. Relieved from the task of producing the right mouth pressure, especially at lower lung volume, the expiratory muscles contribute more to the finer control of mouth pressure modulations. Furthermore, during 'support', the lung volume at which playing a phrase ends is usually above Functional Residual Capacity (FRC) and rarely far below it. The strong expiratory muscle pressures required to play the flute at low lung volumes are generally avoided, while advantage is taken of the high relaxation pressures at high lung volumes. For this study, we compared the respiratory patterns and muscle recruitment above and under FRC while four standing young professional flautists' were performing melodies and long tones with and without 'breath support' at different intensities. These musical tasks required the performers to use most of their vital capacity during loud playing. Recordings included optoelectronic plethysmographic measurements of the chest wall volume and its compartments, surface electromyography of the respiratory muscles (scalene, lateral abdominal, rectus abdominus, and sternocleidomastoid), mouth pressure, and sound. Preliminary analysis suggests that volume (rather than time only), condition (with/without support), as well as intensity (forte/piano) are all determinants of muscle activation.

Expulsive maneuvers (EMs) caused by simultaneous contraction of diaphragm and abdominal muscles shift substantial quantities of blood from the splanchnic circulation to the extremities. This suggests that the diaphragm assisted by abdominal muscles might accomplish ventilation and circulation simultaneously by repeated EMs. We tested this hypothesis in normal subjects by measuring changes (Δ) in body volume (Vb) by whole body plethysmography simultaneously with changes in trunk volume (Vtr) by optoelectronic plethysmography, which measures the same parameters as whole body plethysmography plus the volume of blood shifts (Vbs) between trunk and extremities: Vbs = ΔVtr-ΔVb. We also measured abdominal pressure, pleural pressure, the arterial pressure wave, and cardiac output (Qc). EMs with abdominal pressure ~100 cmH(2)O for 1 s, followed by 2-s relaxations, repeated over 90 s, produced a "stroke volume" from the splanchnic bed of 0.35 ± 0.07 (SD) liter, an output of 6.84 ± 0.75 l/min compared with a resting Qc of 5.59 ± 1.14 l/min. Refilling during relaxation was complete, and the splanchnic bed did not progressively empty. Diastolic pressure increased by 25 mmHg during each EM. Between EMs, Qc increased to 7.09 ± 1.14 l/min due to increased stroke volume and heart rate. The circulatory function of the diaphragm assisted by simultaneous contractions of abdominal muscles with appropriate pressure and duration at 20 min(-1) can produce a circulatory output as great as resting Qc, as well as ventilation. These combined functions of the diaphragm have potential for cardiopulmonary resuscitation. The abdominal circulatory pump can act as an auxiliary heart.