Impedance phlebography. Critical evaluation of its relation to inspiratory capacity.
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Adult↗
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Forced inspiratory measurements and the vital and inspiratory capacities.
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Adult↗
[Respiratory function tests in normal subjects. Predictive equations in the calculation of inspiratory capacity, expiratory reserve and dynamic pulmonary volumes].
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Adolescent↗
[The significance of forced inspiratory capacity for the diagnosis of stenosing processes in the area of larynx and trachea].
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Goiter↗
Respiratory muscle fatigue after marathon running.
Respiratory muscle fatigue has been demonstrated in the laboratory as well as in pathological states, but whether it occurs in healthy individuals under physiological conditions is unknown. To determine whether fatigue of the respiratory muscles may develop with endurance exercise, we measured spirometry and respiratory muscle strength and endurance in four runners before and after completion of a marathon race (42.2 km). Strength was assessed by measuring maximal inspiratory (PImax) and expiratory (PEmax) pressures and transdiaphragmatic pressure during inspiratory capacity (PdiIC); endurance was determined by measuring maximal voluntary ventilation (MVV). After marathon running (mean time, 3 h 24 min) there was no change in forced vital capacity, inspiratory capacity, or flow rates from prerace values. Decreases were observed between pre- and postrace PImax (165.8 +/- 11.0 vs. 138.5 +/- 7.6 cmH2O; P less than 0.01) PEmax (240.0 +/- 20.4 vs. 173.0 +/- 22.6 cmH2O; P less than 0.05), PdiIC (78.8 +/- 11.6 vs. 63.3 +/- 7.0 cmH2O; P less than 0.10), and MVV (178 +/- 24.2 vs. 161.2 +/- 23.2 l/min; P less than 0.005). The decrements in respiratory muscle strength and endurance suggest the development of respiratory muscle fatigue after marathon running.
Adult↗
The effects of nebulized salbutamol on lung function and exercise tolerance in patients with severe airflow obstruction.
The effects of 10 mg of nebulized salbutamol on lung mechanics and exercise tolerance in 10 patients with severe airflow obstruction are described. All patients were previously considered to have irreversible airflow obstruction as demonstrated by little or no improvement in expiratory flow rates either during a corticosteroid trial or after inhalation of 100 micrograms of isoprenaline. There was a small improvement in expiratory flow rate after nebulized salbutamol but the greatest increases were seen in slow vital capacity, inspiratory capacity, inspiratory flow rates, dynamic compliance during tidal breathing, mid-inspiratory and expiratory pulmonary resistance and exercise tolerance. The mechanism of these effects and their therapeutic significance is discussed.
Aged↗
Effect of large-volume paracentesis on pulmonary function in patients with cirrhosis and tense ascites.
The effect of large-volume paracentesis on lung function was evaluated in 12 male patients with cirrhosis. All underwent pulmonary function tests including spirometry, plethysmography and single-breath carbon-monoxide diffusing capacity 1 day before and after paracentesis. The amount of ascitic fluid removed ranged from 3.6 to 131 (mean +/- SD, 7.4 +/- 3.01). After paracentesis, forced vital capacity, forced expiratory volume at 1 s, total lung capacity, functional residual capacity, inspiratory capacity, expiratory reserve volume, diffusing capacity and alveolar volume increased significantly. In contrast, Kco (diffusing capacity corrected by alveolar volume) decreased significantly. After paracentesis, the increase in diffusing capacity was highly correlated with lung volumes and the amount of removed ascitic fluid. Nevertheless, a significantly negative correlation was found between the change of Kco before and after paracentesis and that of lung volumes. The increase in lung volumes and ventilation to the lower lungs with unfavorable ventilation-perfusion matching might explain the discrepancy between changes in diffusing capacity and Kco after large-volume paracentesis. In conclusion, these results suggest that pulmonary function in patients with cirrhosis and tense ascites is partly improved by large-volume paracentesis. Large-volume paracentesis might be useful for symptomatic relief in selected patients with tense ascites.
Ascites↗
Combined effects of ozone and nitrogen dioxide on respiratory function in man.
Ten young adult males were exposed to either filtered air or 0.50 ppm ozone plus 0.50 ppm NO2 in filtered air under four environmental conditions: 25 degree C, 45 % rh; 30 degrees C, 85% rh; 35 degrees C, 40% rh; and 40 degrees C, 50% rh. There were eight 2-hour exposures per subject. After 1 hour of sitting exposure the subjects exercised for 30 minutes (35-40% predicted maximum capacity) which increased ventilatory exchange to approximately 40 L/min (BTPS). Pulmonary function tests were performed before, during, and after exposure. Metabolism and ventilation were determined during the last 15 minutes of exercise. A symptom questionnaire was completed at the termination of each exposure following reexamination by a physician. There was a decrease in vital capacity, inspiratory capacity, and several flow-related measures of lung function during exposure. The response to exposure to the combined pollutants (O3 and NO2) was similar to that observed in ozone exposures alone. No synergism was observed.
Adult↗
Changes in respiratory function tests during pregnancy.
Anatomical, physiological and biochemical adaptations that occur during pregnancy are profound. Changes in respiratory physiology are a part of the same process. In the present study of 70 selected women, 50 pregnant and nonpregnant control, it was found that out of seven parameters studied five showed changes. There were changes in respiratory frequency, tidal volume, vital capacity, inspiratory capacity and expiratory reserve volume. Maximum voluntary ventilation and timed vital capacity did not change. RF, VT, VC and IC rose significantly while ERV had a significant fall. These changes may be affecting ante-intranatal behaviour of pregnant women and their pregnancy outcome.
Adult↗
Understanding pulmonary function tests.
Lung volume measurements include vital capacity, inspiratory capacity, expiratory reserve volume, functional residual capacity, residual volume, total lung capacity and tidal volume. Minute ventilation and forced vital capacity help to determine the patient's ability to move air. Other tests measure parameters such as diffusion across the alveolocapillary membrane and gas distribution. Combined with blood gas measurements, these tests are invaluable in the study of dyspneic patients and patients undergoing major surgery, in monitoring of pulmonary disease and in selection of therapy.
Humans↗
Changes in lung volume and rib cage configuration with abdominal binding in quadriplegia.
Previous studies suggest that abdominal binding may affect the interaction of the rib cage and the diaphragm over the tidal range of breathing in quadriplegia. To determine whether abdominal binding influences rib cage motion over the entire range of inspiratory capacity, we used spirometry and the helium-dilution technique to measure functional residual capacity (FRC), inspiratory capacity, and total lung capacity (TLC) in eight quadriplegic and five normal subjects in supine, tilted (37 degrees), and seated positions. Combined data in all three positions indicated that, with abdominal binding, FRC and TLC decreased in normal subjects [delta FRC = -0.33 + 0.151 (SD) P less than 0.01); delta TLC = -0.16 + 0.121, P less than 0.05]. In quadriplegia there was also a reduction in FRC with binding (delta FRC = -0.32 + 0.101, P less than 0.001). However, TLC increased in quadriplegia (delta TLC = 0.07 + 0.061, P less than 0.025). In an additional six quadriplegic and five normal subjects, we used magnetometers to define the influences of abdominal binding on rib cage dimensions and TLC. In quadriplegia, rib cage dimensions were increased at TLC with abdominal binding, whereas there was no change in normals. Our data suggest that this inspiratory effect of abdominal binding on augmenting rib cage volume in quadriplegia is greater than the effect of impeding diaphragm descent, and thus abdominal binding produces a net increase in TLC in quadriplegia.
Abdomen↗
Lung volumes, chest wall configuration, and pattern of breathing in microgravity.
We studied the changes in functional residual capacity (FRC), thoracoabdominal volume (Vw), and chest wall configuration in five normal subjects seated in an aircraft flying parabolic trajectories resulting in 20-s periods of microgravity. We measured vital capacity (VC), inspiratory capacity, and tidal volume by integrating airflow at the mouth and changes in rib cage and abdominal volume (delta Vrc and delta Vab, respectively, where delta Vrc + delta Vab = delta Vw) using induction plethysmography. During microgravity (0 Gz) FRC decreased by 413 +/- 70 (SE) ml and VC by 0.37 liter. The decrease in Vw did not differ from that in FRC and was entirely the result of reduction of Vab, the Vrc showing no significant change. During tidal breathing the abdominal contribution (delta Vab/delta Vw) increased from 0.39 +/- 0.08 at 1 Gz to 0.57 +/- 0.08 at 0 Gz. During brief periods of hypergravity (approximately 1.8 Gz) all changes were opposite in sign and relatively smaller. Limited data during "roller coaster" flight patterns suggested that, in contrast to configurational changes, the temporal pattern of breathing was uninfluenced by changes in Gz. We conclude that at the onset of weightlessness there are substantial changes in lung volume and thoracoabdominal configuration. Abdominal contribution to tidal excursions increases but the temporal pattern of breathing is unchanged.
Abdomen↗
Pulmonary mechanisms of the normal ferret.
Pulmonary mechanics were measured in normal anesthetized male Fitch ferrets (200-360 g). In eight transorally intubated ferrets, pressure-volume (PV) curves for the lung and chest wall were obtained with an esophageal balloon and body plethysmograph. The lung volumes and capacities expressed as a percentage of the total lung capacity (mean, 49.8 ml) were: vital capacity, 84.7%; inspiratory capacity, 63.7%; inspiratory reserve volume, 58.2%; functional residual capacity, 33.8%; expiratory reserve volume, 16.8%; residual volume, 15.3%; and tidal volume, 8.0%. The compliance of the lung (2.93 ml . cmH2O-1), chest wall (22.42 ml . cmH2O-1) and respiratory system (2.55 ml . cmH2O-1) were determined from the PV curves. The dynamic compliance (1.6 ml . cmH2O-1), pulmonary resistance (0.024 cmH2O . ml-1 . s), frequency of breathing (43.5 breaths . min-1), and minute ventilation (195 ml . min-1) were measured during spontaneous breathing. In a second group of 10 ferrets the total airway resistance (0.116 cmH2O . ml-1 . s) and specific conductance (0.915 ml . s-1 . cmH2O . ml-1) were measured during spontaneous nasal breathing. In general the pulmonary mechanics of the ferret were similar to those of the rabbit and dog, when the data were normalized for lung volume.
Airway Resistance↗
Effects of expiratory threshold loading during steady-state exercise.
Increases in functional residual capacity (FRC) decrease inspiratory muscle efficiency; the present experiments were designed to determine the effect of FRC change on the ventilatory response to exercise. Six well-trained adults were exposed to expiratory threshold loads (ETL) ranging from 5 to 40 cmH2O during steady-state exercise on a bicycle ergometer at 40-95% VO2max. Inspiratory capacity (IC) was measured and changes of IC interpreted as changes of FRC. ETL did not consistently limit exercise performance. At heavy work (greater than 92% VO2max) minute ventilation decreased with increasing ETL; at moderate work (less than 58% VO2max) it did not. Decreases in ventilation were due to decreases in respiratory frequency with prolongation of the duration of expiration being the most consistent change in breathing pattern. At moderate work levels, FRC increased with ETL; at maximum work it did not. Changes in FRC were dictated by constancy of tidal volume and a fixed maximum end-inspiratory volume of 80-90% of the inspiratory capacity. When tidal volume was such that end-inspiratory volume was less than this value, FRC increased with ETL. Mouth pressure measured during the first 0-1 s of inspiratory effort against an occluded airway (P0-1) was increased by ETL equals 30 cmH2O, in spite of the fact that ventilation was decreased. We concluded that changes in FRC due to ETL had no effect on the ventilatory response to exercise and that changes in P0-1 induced by ETL did not reflect changes of inspiratory drive so much as changes of the pattern of inspiration.
Adult↗
Influence of lung volume on sympathetic nerve discharge in normal humans.
The purpose of this study was to determine the influence of tidal volume, breathing pattern, and beginning lung volume on the modulation of efferent, muscle sympathetic nerve activity (MSNA) in humans. In seven supine, healthy subjects, we measured MSNA (microneurography of the right peroneal nerve) and beat to beat arterial blood pressure during 1) low-frequency breathing (fb = 12 breaths/min) at tidal volumes (VT) of 30% (control), 50%, and 70% of inspiratory capacity and with inspiratory time-to-total breath time ratios (TI/TTOT) of 0.3-0.5 (control), less than 0.3, and greater than 0.5; and 2) simulated exercise hyperpnea (fb = 40 breaths/min; VT = 60-70% inspiratory capacity; minute ventilation, approximately 90 1). To optimize our ability to discern modulatory effects, breathing was performed during three conditions of heightened MSNA: nonhypotensive (less than 20 mm Hg) lower-body negative pressure, isometric handgrip exercise, and posthandgrip vascular occlusion (ischemia). PETCO2 was maintained at normal levels by adjusting the FICO2. Within-breath modulation of MSNA was observed during control tidal breathing with approximately 65% of the burst frequency occurring during the expiratory phase. Deep, low-frequency breathing potentiated this modulatory influence (p less than 0.05 versus control) and produced near-complete sympathoinhibition from onset-mid inspiration to early-mid expiration. Increasing (slow inspiration) and decreasing (fast inspiration) TI/TTOT shifted the onset of sympathoinhibition occurring later (greater change in volume) and earlier (less change in volume) during inspiration, respectively. In two subjects who performed deep breathing from an elevated beginning lung volume, the sympathoinhibition was observed earlier in the inspiratory period and with less change in volume compared with control. These within-breath modulatory effects did not appear to be due solely to changes in arterial pressure. Sustained low- or high ("exerciselike")-frequency deep breathing did not alter total minute MSNA compared with control breathing. These results demonstrate that the depth and pattern of breathing, and possibly the starting lung volume, exert marked influences on the within-breath modulation of MSNA in humans. Our findings also suggest that these modulatory effects may be mediated, at least in part, by pulmonary stretch reflexes.
Adult↗
Pulmonary reaction to upper mantle radiation therapy for Hodgkin's disease.
To study the effects of upper mantle radiation therapy on pulmonary function, forced expiratory volume in one second (FEV1), vital capacity (VC), inspiratory capacity (IC), diffusing capacity for CO (DLCO) and diffusion per unit of alveolar volume (DL/VA were determined in 28 patients with Hodgkin's disease, stages 1--3, before therapy and at regular intervals thereafter. Within the first year of follow-up there were significant declines in DLCO, VC, and IC, whereas there were no significant changes in FEV1 or DL/VA. DLCO showed the greatest decline in the largest number of subjects (22/28). Eleven of the 22 had 20 to 60 percent decline of DLCO from baseline. The maximum mean decline in DLCO was -12.7 +/- 3 percent at the 87th +/- 3 days from initiation of therapy postradiation sustained through the 150th day and improving to pretreatment value (+/- 5 percent) by the 8th to 12th month. The changes in DLCO seemed to be independent of the radiation dose ranges evaluated, clinically apparent intrathoracic lymphoma, postradiation radiographic abnormalities and respiratory symptoms. We concluded that impairment in diffusing capacity and loss of vital capacity will develop in most patients receiving upper mantle radiation therapy, indicating that pulmonary reaction occurs despite lung shielding. The functional losses were prolonged and occasionally severe, but were transient and subclinical in most but not all cases. A case of fatal radiation pneumonitis affecting the lung beyond the field of irradiation is reported.
Adolescent↗
Changes in lung volume and deflation stability in hyaline membrane disease.
Total lung capacity (TLC), inspiratory capacity, functional residual capacity, and deflation stability of prematurely delivered Macaca nemestrina primates were measured serially during development of, and recovery from, hyaline membrane disease (HMD) to relate changes in lung volumes to changes in deflation stability. Gestational age-matched primates that did not develop HMD served as controls. TLC, measured by N2 washout, fell at 2-12 h of age (P less than 0.0001) in animals with HMD and remained lower than controls for at least 48 h (P less than 0.005). However, deflation stability, defined as the fraction of TLC remaining upon deflation to 10 cm H2O, improved from 2 to 12 h of age (P less than 0.001). Postmortem studies confirm the measurements of TLC and deflation stability and provide evidence that interstitial thickening and obstruction of air spaces with debris may be partially responsible for the observed changes in TLC in primates that develop HMD. It has been assumed that TLC is reduced in HMD because of atelectasis from elevated alveolar surface tension, but the sequential measurements in these animals suggest that other mechanisms also contribute.
Animals↗
[Dyspnea and inspiratory effort capacity in COPD].
The aim of this work was to study the relationship between dynamic hyperinflation and dyspnoea perception on exercise in patients with chronic obstructive pulmonary disease (COPD). Seven men and three women with COPD (mean FEV1 45.9 +/- 9.8% predicted) were studied. The upper end of the visual analogue scale was anchored on a preliminary test on a cycle ergometer (day 1). On the study day (day 2) the relationship between dyspnoea and ventilatory indices during high intensity exercise was evaluated, using within-subject linear regression analysis. On a repeat study (day 3), the addition of inspiratory capacity (IC) manoeuvres allowed to monitor the end expiratory lung volume. The highest degree of within-subject correlation was observed between dyspnoea and the tidal peak inspiratory flow (PIFT), as well without (median r2 = 0.920, day 2) as with (median r2 = 0.880, day 3) IC manoeuvres. At maximal exercise, IC decreased in 8 out of 10 subjects (delta IC range -150 to -900 ml). A negative relationship was found between delta IC and the rate of increase in dyspnoea on exercise, measured as the dyspnoea/PIFT slope (r = 0.844, p < 0.01). Our results suggest that dynamic hyperinflation on exercise observed in most patients with COPD allows these subjects to minimize the rate of increase in dyspnoea on exercise.
Aged↗