Change In Total Lung Capacity Research Articles

Pulmonary function tests correlated with thoracic volumes in adolescent idiopathic scoliosis.

Scoliosis deformity has been linked with deleterious changes in the thoracic cavity that affect pulmonary function. The causal relationship between spinal deformity and pulmonary function has yet to be fully defined. It has been hypothesized that deformity correction improves pulmonary function by restoring both respiratory muscle efficiency and increasing the space available to the lungs. This research aims to correlate pulmonary function and thoracic volume before and after scoliosis correction. Retrospective correlational analysis between thoracic volume modeling from plain x-rays and pulmonary function tests was conducted. Adolescent idiopathic scoliosis patients enrolled in a multicenter database were sorted by pre-operative Total Lung Capacities (TLC) % predicted values from their Pulmonary Function Tests (PFT). Ten patients with the best and ten patients with the worst TLC values were included. Modeled thoracic volume and TLC values were compared before and 2 years after surgery. Scoliosis correction resulted in an increase in the thoracic volume for patients with the worst initial TLCs (11.7%) and those with the best initial TLCs (12.5%). The adolescents with the most severe pulmonary restriction prior to surgery strongly correlated with post-operative change in total lung capacity and thoracic volume (r2 = 0.839; p < 0.001). The mean increase in thoracic volume in this group was 373.1 cm3 (11.7%) which correlated with a 21.2% improvement in TLC. Scoliosis correction in adolescents was found to increase thoracic volume and is strongly correlated with improved TLC in cases with severe restrictive pulmonary function, but no correlation was found in cases with normal pulmonary function. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:175-182, 2017.

Pulmonary Rehabilitation and Noninvasive Ventilation in Patients with Hypercapnic Interstitial Lung Disease

Background: Pulmonary rehabilitation (PR) has a positive impact on functional status and quality of life in patients with interstitial lung disease (ILD). Objectives: This study investigated the effects of PR in hypercapnic ILD patients receiving nighttime noninvasive positive pressure ventilation (NPPV). Methods: Consecutive ILD patients referred to a specialized inpatient PR center were included. All participated in a PR program. Those with hypercapnia received NPPV (NPPV group; n = 29); the remaining patients served as comparison group (n = 319). Results: PR improved the 6-min walk distance by 64.4 ± 67.1 m versus baseline (p < 0.0001) in NPPV patients and by 43.2 ± 55.1 m (p < 0.0001) in the comparison group (difference 21.1 m, 95% confidence interval 0.5-41.8; p = 0.045). There was no change in total lung capacity during PR in NPPV recipients or the comparison group. Forced vital capacity significantly increased from baseline in the comparison, but not the NPPV group. NPPV recipients were significantly more likely than the comparison group to have improved dyspnea during PR (p = 0.049). There was no improvement in the 36-item Short Form (SF-36) physical component score in the NPPV group after PR, but there was in the comparison group. PR improved the SF-36 mental component score versus baseline in both groups. Conclusion: An individually tailored PR plus nighttime NPPV appears feasible in hypercapnic ILD patients and significantly improves exercise capacity and quality of life.

Early Changes in Pulmonary Function After Vertical Expandable Prosthetic Titanium Rib Insertion in Children With Thoracic Insufficiency Syndrome

The vertical expandable prosthetic titanium rib (VEPTR) has been inserted in children with thoracic insufficiency syndrome for the last decade to expand and support the chest and allow for further lung growth. There are minimal published data evaluating the postoperative change in lung function after VEPTR insertion. We hypothesize that there will be a significant increase in lung function after VEPTR insertion, and the earlier the insertion, the greater the improvement. The Chest Wall Disorders Study Group Database, containing data before and after VEPTR insertion from 7 different centers, was queried for spirometry and lung volume measurements, and the data were analyzed to assess the short-term effect on lung function of VEPTR placement. There was a statistically significant decrease in forced vital capacity, forced expiratory volume in 1 second as a percent of predicted, an increase in residual volume (RV) that did not reach statistical significance, and there was no change in total lung capacity at the first postoperative visit (7.7 +/- 4.8 months). There was a significant decrease in Cobb angle. There was no correlation between absolute change in any pulmonary function and Cobb angle age at the time of surgery. Although there is a clinically and radiographically apparent expansion of the thorax after VEPTR insertion, there is no similar improvement in lung volume, and instead there is a decrease in forced vital capacity and increase in residual volume, the explanation for which requires further study. This lack of change in pulmonary function after VEPTR insertion suggests that the benefit of VEPTR insertion may lie more in stabilizing the thorax and improving respiratory mechanics measured in other ways.

Mechanical ventilatory constraints during incremental cycle exercise in human pregnancy: implications for respiratory sensation

The aim of this study was to identify the physiological mechanisms of exertional respiratory discomfort (breathlessness) in pregnancy by comparing ventilatory (breathing pattern, airway function, operating lung volumes, oesophageal pressure (P(oes))-derived indices of respiratory mechanics) and perceptual (breathlessness intensity) responses to incremental cycle exercise in 15 young, healthy women in the third trimester (TM(3); between 34 and 38 weeks gestation) and again 4-5 months postpartum (PP). During pregnancy, resting inspiratory capacity (IC) increased (P < 0.01) and end-expiratory lung volume decreased (P < 0.001), with no associated change in total lung capacity (TLC) or static respiratory muscle strength. This permitted greater tidal volume (V(T)) expansion throughout exercise in TM(3), while preserving the relationship between contractile respiratory muscle effort (tidal P(oes) swing expressed as a percentage of maximum inspiratory pressure (P(Imax))) and thoracic volume displacement (V(T) expressed as a percentage of vital capacity) and between breathlessness and ventilation . At the highest equivalent work rate (HEWR = 128 +/- 5 W) in TM(3) compared with PP: , tidal P(oes)/P(Imax) and breathlessness intensity ratings increased by 10.2 l min(-1) (P < 0.001), 8.8%P(Imax) (P < 0.05) and 0.9 Borg units (P < 0.05), respectively. Pulmonary resistance was not increased at rest or during exercise at the HEWR in TM(3), despite marked increases in mean tidal inspiratory and expiratory flow rates, suggesting increased bronchodilatation. Dynamic mechanical constraints on V(T) expansion (P < 0.05) with associated increased breathlessness intensity ratings (P < 0.05) were observed near peak exercise in TM(3) compared with PP. (1) pregnancy-induced increases in exertional breathlessness reflected the normal awareness of increased and contractile respiratory muscle effort; (2) mechanical adaptations of the respiratory system, including recruitment of resting IC and increased bronchodilatation, accommodated the increased V(T) while preserving effort-displacement and breathlessness-VE relationships; and (3) dynamic mechanical ventilatory constraints contributed to respiratory discomfort near the limits of tolerance in late gestation.

Changes in residual volume relative to vital capacity and total lung capacity after arthrodesis of the spine in patients who have adolescent idiopathic scoliosis.

We evaluated pulmonary functions before correction and again after a mean follow-up of three years in thirty-five patients who had adolescent idiopathic scoliosis. The mean age (and standard deviation) at the time of correction was 13.7 +/- 1.8 years, and at the time of follow-up it was 17.1 +/- 2.5 years. The findings in the patients were compared with those in matched normal control subjects. With the exception of forced vital capacity, all of the determinations of absolute pulmonary volume increased postoperatively, but the increases were not all proportional. When the preoperative and follow-up determinations were expressed as percentages of the predicted pulmonary volumes (on the basis of age) to eliminate any effects of the difference in age, there was no change in total lung capacity, but vital capacity and forced vital capacity were significantly reduced. In addition, there was a significant increase in residual volume. Of the mean increase in total lung capacity after correction of the scoliosis, 82 per cent was due to an increase in residual volume and 18 per cent, to an increase in vital capacity. However, in control subjects age-matched at the time of follow-up, the increase in vital capacity contributed 69 per cent of the mean increase in total lung capacity, a very marked difference from the findings in the patients who had scoliosis. In addition, two pulmonary-volume ratios--residual volume to vital capacity and residual volume to total lung capacity--increased in a highly significant fashion (Mann-Whitney test, p < 0.001) after arthrodesis of the spine.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of continuous positive airway pressure breathing on lung volume and distensibility

In this study the effects on lung elastic behavior of 10 min of breathing at a continuous positive airway pressure (CPAP) of 10 cmH2O were examined in 10 normal subjects. To investigate whether any changes were induced by release of prostaglandins, the subjects were also pretreated with the cyclooxygenase inhibitor indomethacin. CPAP produced a significant (P less than 0.001) upward shift of the pressure-volume (PV) curve [change in total lung capacity (delta TLC) 374 +/- 67 (SE) ml, mean delta volume at a transpulmonary pressure of 15 cmH2O (delta VL15) 279 +/- 31 ml] with no change in K, an index of lung distensibility. After CPAP the PV curves returned to normal base line within 20 min. The same pattern was observed after indomethacin, but the increase in TLC was significantly less (P less than 0.01) (mean delta TLC 206 +/- 42 ml) mainly because of a slight and not statistically significant increase in base-line TLC. In five subjects further PV curves with and without CPAP were obtained greater than or equal to 7 days after indomethacin. The responses were not significantly different from those obtained before indomethacin (mean delta TLC 366 +/- 89, mean delta VL15 296 +/- 42 ml). We conclude that CPAP produces an upward shift of the PV curve without a change in lung distensibility. In addition, there may be a small degree of resting alveolar duct tone that is influenced by indomethacin.

Impaired pulmonary and cardiac function after maximal exercise.

The cardiopulmonary response to maximal rowing exercise of short duration was studied in six healthy well-trained oarsmen. The lung diffusing capacity for carbon monoxide was significantly decreased below the pre-exercise value for 2.5 days post-exercise (P less than 0.05). Residual volume (RV) showed a significantly increased value at 30 min of recovery (P less than 0.01) with no change in total lung capacity. There was no significant change in transthoracic electrical impedance following exercise but a decrease may have been masked by the increased RV. The changes in the pulmonary parameters may reflect the occurrence of a transient interstitial lung oedema. Exercise-induced bronchoconstriction may be a part of the cardiopulmonary response as peak expiratory flow rate (PEFR) was significantly reduced at 30 min of recovery. The reason for the increase in pulmonary extravascular water volume may be a marked distension of the lung capillaries due to increased blood volume in the lungs and as a consequence increased vascular permeability. The changes may also be caused by impaired myocardial contractility indicated by a split impedance dZ/dt waveform, not previously described in healthy persons, which occurred in all six subjects immediately following exercise.

Fluid trapping in postmortem guinea pig lungs.

To examine severe bronchoconstriction obstructing airways in the fluid-filled postmortem guinea pig lung, lungs were infused and deflated with isotonic solution following exsanguination. Guinea pigs were classified into 2 groups: young and mature, and each group was further classified into 2 subgroups: those receiving saline (Ca2+-free) and Tyrode's (Ca2+-containing) solutions. Each subgroup consisted of 7-8 animals. No significant change in total lung capacity from the baseline (prior to exsanguination) air value was observed in any subgroup within the experimental period of 60 min. However, both deflation volume (DV) and inflation volume (IV) decreased gradually with time; these decreases were larger in the saline-filled lungs than those of lungs infused with Tyrode's solution at 20-30 min. In the Tyrode's solution-filled lungs, larger decreases in DV and IV were found in the mature animals than in the young animals at 15-20 min. Trapped fluid volume (VT) increased gradually with time and reached mean values ranging from 9.1 to 11.5 times the baseline value at 60 min. No significant difference in VT between subgroups was observed. At any given time in all animals, the increase in VT was always equal to or larger than the decrease in DV or IV. Fluid cuffing around vessels and airways was demonstrated in the saline, but not in the air-filled lung. The data suggest that severe bronchoconstriction obstructing airways did not occur in postmortem fluid-filled guinea pig lungs. Dilution of mediators may be responsible for eliminating postmortem severe airway spasm and swelling of interstitium may induce the temporal increase in trapped volume in the fluid-filled lung.

Canine bronchoconstriction, gas trapping, and hypoxia with methacholine.

The effects of an intravenous methacholine infusion on cardiovascular-pulmonary function were measured in seven mongrel dogs (22.0 +/- 2.8 kg), anesthetized with chloralose and urethan and beta-adrenergically blocked with propranolol. In a volume-displacement plethysmograph, physiological measurements were made at base line and 25 min after establishing a methacholine infusion (0.1-1.0 mg X kg-1 X h-1). Methacholine significantly (P less than 0.05) increased airways resistance (1.9 +/- 0.8 to 8.2 +/- 2.9 cmH2O X l-1 X s), decreased static lung compliance (84.7 +/- 18.5 to 48.2 +/- 9.4 ml/cmH2O), depressed arterial PO2 (81 +/- 17 to 56 +/- 10 Torr), and lowered blood pressure (132 +/- 10 to 69 +/- 18 Torr) and cardiac output (5.7 +/- 1.9 to 4.1 +/- 1.2 l/min). These effects persisted during a further 80 min of methacholine infusion conducted in five of the animals. During the initial 25-min period of methacholine, the end-expired volume (volume-displacement Krogh spirometer) rose in all animals, indicating an increase in functional residual capacity from 997 +/- 115 to 1,623 +/- 259 ml (P less than 0.0005). Analysis of pulmonary pressure-volume curves revealed no change in total lung capacity but an increase in residual volume from 489 +/- 168 to 1,106 +/- 216 ml (P less than 0.001). Thus methacholine caused 617 ml of gas trapping, which was not detected by the Boyle's law principle, presumably because gas was trapped at high transpulmonary pressure. We suggest that intravenous methacholine-induced canine bronchoconstriction, which causes gas trapping and hypoxia, may be a useful animal model of clinical status asthmaticus.

Suppression of the alveolitis in pulmonary sarcoidosis by oral corticosteroids.

We evaluated the effects of daily prednisone therapy on alveolitis parameters and pulmonary function tests over a six month period in patients with active pulmonary sarcoidosis (>28% T lymphocytes in bronchoalveolar lavage and positive gallium-67 (67Ga) lung scans). 10 patients with biopsyproven lung disease were studied. Analysis of bronchoalveolar lavage cells and of67Ga scanning at the beginning and at the end of the study period demonstrated that prednisone treatment significantly lowered the percentages of T lymphocytes in bronchoalveolar lavage in all patients (baseline 48±3%, after treatment 19±5%, p<0.01) while67Ga lung scans improved in 8 of the 10 patients. Pulmonary function tests showed improvement of the parameters studied (+7.5±2.1% mean change in vital capacity, +4.7±1.6% mean change in total lung capacity, +5.4±2% mean change in forced expiratory volume in one second and +6.2±1.5% mean change in diffusing capacity). In addition none of the treated patients deteriorated functionally and 9 of the 10 patients improved more than 10% in at least one parameter.

Shape of small opacities and lung function in coalworkers.

Lung function and chest radiographs were reviewed in 357 coalworkers who had been referred from the Cardiff Pneumoconiosis Medical Panel. The chest films were read according to the 1980 ILO classification of radiographs by three experienced readers. An irregularity score, reflecting the shape of the small opacities, was derived from the readings and compared with the lung function variables. Men with higher irregularity scores had significant reductions in ventilatory capacity and gas transfer factor, with no change in total lung capacity, after age, height, profusion of small opacities, and smoking habit had been taken into account. The effects were present both in those with and in those without large opacities. The agreement between readers over the shape of opacities was almost as good as for their profusion. Men with rounded opacities had a lower gas transfer factor if they were predominantly of the "p" type. The results are consistent with those for a combination of emphysema and interstitial fibrosis, which has been found in coalworkers with irregular opacities.

Maximal expiratory flows in coal miners.

From a group of approximately 9,000 working coal miners studied by the U. S. Public Health Service in 1973 and 1974, 4 groups of 428 age- and height-matched subjects were selected according to their smoking habits and according to whether or not they had bronchitis. Flow-volume curves, lung volumes, and the more commonly used indices of ventilatory capacity, the forced vital capacity and the forced expiratory volume in 1 sec, had been measured previously in each subject. A larger total lung capacity was observed in smoking than in nonsmoking miners, whether bronchitic or not. This phenomenon is believed to indicate a loss of retractive forces due to destruction of the lung parenchyma associated with cigarette smoking. No comparable change in total lung capacity was observed in the nonsmoking miners with bronchitis. Because dust-induced bronchitis in nonsmoking miners is associated with a decrease in flows at high lung volumes in the absence of an increase in total lung capacity, it is inferred that indust...