Oxygen cost of increasing tidal volume and diaphragm flattening in obstructive pulmonary disease

1993 ◽  
Vol 74 (6) ◽  
pp. 2750-2756 ◽  
Author(s):  
W. D. Pitcher ◽  
H. S. Cunningham
Keyword(s):  
Tidal Volume ◽  
Pulmonary Disease ◽  
Breathing Pattern ◽  
Minute Ventilation ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Oxygen Cost ◽  
Obstructive Pulmonary Disease ◽  
Shallow Breathing

Hypercapnia is associated with a shallow breathing pattern in patients with severe chronic obstructive pulmonary disease (COPD). We sought to determine the oxygen cost of increasing tidal volume and to relate this to hypercapnia [arterial PCO2 (PaCO2) > or = 45 Torr] and diaphragm flattening. We studied 3 normal subjects and 12 patients with stable but comparably severe COPD (forced expired volume in 1 s 1.01 +/- 0.09 liters) who had baseline PaCO2 ranging from 36 to 56 Torr. Oxygen consumption was measured during the subject's native breathing pattern and then while tidal volume was increased by 20%; minute ventilation was held constant by proportionately slowing frequency. There was a significant oxygen cost of increasing tidal volume for hypercapnic patients (235 +/- 23 to 260 +/- 25 ml O2/min; P = 0.002); no significant oxygen cost was observed in normal or eucapnic patients. This oxygen cost was positively correlated to baseline PaCO2 (r2 = 0.88, P < 0.001) and degree of diaphragm flattening assessed from chest radiographs (r2 = 0.74, P < 0.05). Although others have shown that force generation is preserved during chronic hyperinflation (G. A. Farkas and C. Roussos. J. Appl. Physiol. 54: 1635–1640, 1983; T. Similowski et al. N. Engl. J. Med. 325: 917–923, 1991), we conclude that diaphragm flattening produces mechanical inefficiency that may contribute to limiting the effective operating range of the respiratory muscles during tidal breathing.

scholarly journals Respiratory pattern, thoracoabdominal motion and ventilation in chronic airway obstruction

2016 ◽  
Vol 67 (4) ◽  
Author(s):  
M. Fernandes ◽  
A. Cukier ◽  
N. Ambrosino ◽  
J.J. Leite ◽  
M.I. Zanetti Feltrim
Keyword(s):  
Breathing Pattern ◽  
Minute Ventilation ◽  
Respiratory Pattern ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Copd Patients ◽  
Lower Oxygen ◽  
Shallow Breathing ◽  
Diaphragmatic Movement ◽  
Severe Copd

Background. Patients with chronic obstructive pulmonary disease (COPD) present abnormal respiratory mechanics, but its relation to ventilation variables at rest is not fully understood. Methods. We evaluated breathing pattern, thoracoabdominal motion, and ventilation in moderate and severe COPD patients by means of respiratory inductive plethysmograph and analysis of respiratory metabolism in semirecumbent position at rest. Diaphragmatic movement was measured using radiographs. Results. COPD patients showed an increase in mean inspiratory flow, minute ventilation, dead space ventilation, oxygen and carbon dioxide ventilatory equivalents and reduction of respiratory times and pulse oxymetry. These findings were more pronounced in severe COPD. Changes in ventilatory efficiency were correlated with decreased respiratory times, reduced diaphragmatic movement, and lower oxygen uptake. Conclusions. Rapid shallow breathing and reduced diaphragmatic movement have led to ventilatory inefficiency without changes in thoracoabdominal motion.

scholarly journals Comparison of the Oxygen Cost of Breathing Exercises and Spontaneous Breathing in Patients With Stable Chronic Obstructive Pulmonary Disease

2003 ◽  
Vol 83 (5) ◽  
pp. 424-431 ◽  
Author(s):  
Alice YM Jones ◽  
Elizabeth Dean ◽  
Cedric CS Chow
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Oxygen Consumption ◽  
Pulmonary Disease ◽  
Spontaneous Breathing ◽  
Breathing Pattern ◽  
Work Of Breathing ◽  
Chronic Obstructive ◽  
Oxygen Cost ◽  
Obstructive Pulmonary Disease ◽  
Breathing Exercises

Abstract Background and Purpose. The oxygen demand of breathing exercises and the clinical implications have not been studied in detail. In this study, the oxygen cost of 3 common breathing exercises believed to reduce oxygen cost (ie, work of breathing) was compared with that of spontaneous breathing in patients with chronic obstructive pulmonary disease (COPD). Subjects. Thirty subjects with stable, moderately severe COPD participated. Methods. Oxygen consumption (V̇o2) and respiratory rate (RR) during spontaneous breathing at rest (SB) were recorded for 10 minutes. Subjects then performed 3 breathing exercises in random order, with a rest between exercises: diaphragmatic breathing (DB), pursed-lip breathing (PLB), and a combination of DB and PLB (CB). Oxygen consumption and RR were measured. Results. Mean V̇o2 (±SD) was lower during the breathing exercises (165.8±22.3 mL O2/min for DB, 164.8±20.9 mL O2/min for PLB, and 167.7±20.7 mL O2/min for CB) compared with SB (174.5±25.2 mL O2/min). Correspondingly, mean RR (±SD) was higher during SB (17.3±4.23 breaths/min), followed by DB (15.0±4.32 breaths/min), PLB (12.8±3.53 breaths/min), and CB (11.2±2.7 breaths/min). Discussion and Conclusion. Given that patients do not spontaneously adopt the breathing pattern with the least V̇o2 and the lowest RR, the results suggest that determinants of the breathing pattern other than metabolic demand warrant being a primary focus in patients with COPD.

Efficacy of diaphragmatic breathing in patients with chronic obstructive pulmonary disease

2011 ◽  
Vol 8 (4) ◽  
pp. 237-244 ◽  
Author(s):  
Marcelo Fernandes ◽  
Alberto Cukier ◽  
Maria Ignêz Zanetti Feltrim
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Tidal Volume ◽  
Pulmonary Disease ◽  
Breathing Pattern ◽  
Gas Analysis ◽  
Chronic Obstructive ◽  
Diaphragmatic Breathing ◽  
Obstructive Pulmonary Disease ◽  
Ventilatory Equivalent ◽  
Natural Breathing

This study investigated the effects of diaphragmatic breathing (DB) on ventilation and breathing pattern, seeking to identify predictors of its efficacy in patients with chronic obstructive pulmonary disease (COPD). Twenty-nine patients with moderate and severe COPD were monitored using respiratory inductance plethysmography and metabolic gas analysis. After 4 minutes of natural breathing, subjects completed 2 minutes of DB followed by 4 minutes of natural breathing. Dyspnea was measured using a visual analogue scale. Diaphragmatic mobility was assessed using chest radiography. DB was associated with a significant increase in tidal volume and reduction in breathing frequency, leading to higher ventilation and oxygen saturation, with a reduction in dead space ventilation and ventilatory equivalent for carbon dioxide. A total of 10 subjects with moderate (5) and severe (5) COPD performed DB with asynchronous thoracoabdominal motion, worsening the dyspnea, and decreasing the gain of tidal volume. Diaphragmatic mobility, inspiratory muscular strength, lower scores for dyspnea and hypoxemia as well as coordinated thoracoabdominal motion are associated with effective DB. In patients with COPD, DB can improve breathing pattern and ventilatory efficiency without causing dyspnea in patients whose respiratory muscular system is preserved.

Inspiratory pressure generation: comparison of subjects with COPD and age-matched normals

1988 ◽  
Vol 65 (2) ◽  
pp. 888-899 ◽  
Author(s):  
S. Levine ◽  
M. Gillen ◽  
P. Weiser ◽  
G. Feiss ◽  
M. Goldman ◽  
...  
Keyword(s):  
Treadmill Exercise ◽  
Minute Ventilation ◽  
Respiratory Muscles ◽  
Normal Subjects ◽  
Forced Expiratory Volume ◽  
Component Model ◽  
Chronic Obstructive ◽  
Inspiratory Time ◽  
Obstructive Pulmonary Disease ◽  
Accessory Muscle

We continuously monitored esophageal (Pes) and gastric (Pga) pressures and used these measurements in a three-component model to estimate instantaneous diaphragmatic (DIA), inspiratory accessory muscle (IAM), and postexpiratory recoil (PER) pressures at various times during inspiration. We validated our model both by volume-pressure relationships of the respiratory system (Vrc-Pga and Vab-Pga, where Vrc and Vab are the rib cage and abdominal volumes, respectively) as well as electromyography of the respiratory muscles. Measurements were carried out at rest and during graded treadmill exercise in 11 subjects with chronic obstructive pulmonary disease (COPDs) and 8 age-matched normal subjects (AMNs). AMNs were 59 +/- 2 (SE) yr and had a forced expiratory volume at 1 s (FEV1.0) of 3.6 +/- 0.2 liters; COPDs were 66 +/- 2 yr and had a FEV1.0 of 1.0 +/- 0.1 liters. We noted the following. At rest, both AMNs and COPDs exhibited an increasing DIA pressure (PDIA) across inspiratory time (TI) at rest. As expired minute ventilation increased with exercise intensity, AMNs continued to maintain this PDIA ramp across inspiration; in contrast, COPDs exhibited higher values of PDIA during the first half of TI than during the second half. At all intensities of exercise, COPDs exhibited higher IAM and PER pressures than the AMNs.

Assessment of transdiaphragmatic pressure in humans

1985 ◽  
Vol 58 (5) ◽  
pp. 1469-1476 ◽  
Author(s):  
D. Laporta ◽  
A. Grassino
Keyword(s):  
Pulmonary Disease ◽  
Visual Feedback ◽  
Random Order ◽  
Normal Subjects ◽  
Chronic Obstructive ◽  
Disease Group ◽  
Obstructive Pulmonary Disease ◽  
Transdiaphragmatic Pressure ◽  
Residual Capacity ◽  
Group 1

Maximal force developed by the diaphragm at functional residual capacity is a useful index to establish muscle weakness; however, great disparity in its reproducibility can be observed among reports in the literature. We evaluated five maneuvers to measure maximal transdiaphragmatic pressure (Pdimax) in order to establish best reproducibility and value. Thirty-five naive subjects, including 10 normal subjects (group 1), 12 patients with chronic obstructive pulmonary disease (group 2), and 13 patients with restrictive pulmonary disease (group 3), were studied. Each subject performed five separate maneuvers in random order that were repeated until reproducible values were obtained. The maneuvers were Mueller with (A) and without mouthpiece (B), abdominal expulsive effort with open glottis (C), two-step (maneuver C combined with Mueller effort) (D), and feedback [two-step with visual feedback of pleural (Ppl) and abdominal (Pab) pressure] (E). The greatest reproducible Pdimax values were obtained with maneuver E (P less than 0.01) (group 1: 180 +/- 14 cmH2O). The second best maneuvers were A, B, and D (group 1: 154 +/- 25 cmH2O). Maneuver C produced the lowest values. For all maneuvers, group 1 produced higher values than groups 2 and 3 (P less than 0.001), which were similar. The Ppl to Pdi ratio was 0.6 in maneuvers A and B, 0.4 in D and E, and 0.2 in C. We conclude that visual feedback of Ppl and Pab helped the subjects to elicit maximal diaphragmatic effort in a reproducible fashion. It is likely that the great variability of values in Pdimax previously reported are the result of inadequate techniques.

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