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PubMed2004

Ventilatory response to exercise in simulated obesity by chest loading.

INTRODUCTION & PURPOSE: Obesity-related increases of weight on the chest wall are known to decrease lung volume and chest wall compliance, but the effect of this mass loading, independent of other obesity-related complications on the ventilatory response to exercise is unknown. The purpose of this study was to investigate the effect of chest mass loading on the ventilatory response to exercise. METHODS: External chest loading (CL) was used to simulate the effect of moderate obesity (BMI = 32 kg x m). Eight healthy nonobese subjects performed two incremental exercise tests on a cycle ergometer with work rate increasing 25 W every 3 min once without (control; CON) and once with CL. Expiratory reserve volume (ERV), forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1) were measured before each test. During exercise, inspiratory capacity (IC), to estimate changes in end-expiratory lung volume, and inspiratory (TI) and expiratory (TE) duration, tidal volume (Vt), breathing frequency (Fb), minute ventilation (VE), mean inspiratory (Vt/TI) and expiratory (Vt/TE) flow rates, and oxygen consumption (VO2) were measured. RESULTS: Baseline ERV, FVC and FEV1 were lower with CL (P < 0.05). Compared with CON, the peak work rate achieved during exercise with CL was lower and VO2, VE, Fb, Vt/TI, and Vt/TE were higher, and Vt was lower at work rates > or = 100 W (P < 0.05). IC increased progressively in CON during exercise but remained unchanged with CL. CONCLUSION: Obesity-related chest loading decreases lung volumes and increases the mechanical ventilatory constraints during exercise and is likely a critical factor in reducing exercise capacity in obesity.

Adult↗
PubMed1989

Study of the effects of ozone in emphysematous rats.

The effects of short-term exposure to ozone on control and elastase-induced emphysematous rats were examined to investigate whether emphysema would change the pulmonary susceptibility to oxidant air pollution. Emphysema was induced in rats after a single intratracheal instillation of 0.2 IU elastase/g body weight. Histologically, panacinar emphysema was apparent at 2, 4, 8, and 16 wk, that is, the total duration of the experiment. The diagnosis was confirmed by morphometry: the mean linear intercepts (MLI) of elastase-treated rats were significantly increased at all observation times, whereas the internal surface areas (ISA) of the elastase-treated rats were significantly decreased. In addition, pulmonary function tests provided supportive evidence for the diagnosis of emphysema. Respiratory system compliance and functional residual capacity showed a significant increase in elastase-treated rats. No differences in inspiratory capacity or in forced vital capacity between control rats and elastase-treated rats were observed. The above data are indicative for a rat model for elastase-induced emphysema. Short-term exposure to ozone of elastase-treated rats revealed panacinar emphysema, including an inflammatory response in the centroacinar region. No differences in MLI as well as in ISA between ozone-exposed rats (with or without emphysema) and their respective controls were observed. Short-term exposure to ozone induced an identical, significant increase in protein content, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, and glutathione peroxidase activities in lungs of normal and emphysematous rats. Moreover, these results strongly suggest that emphysematous rats are not more susceptible to ozone than nonemphysematous rats.

Air Pollutants↗
PubMedDate not supplied

A multivariate study of some lung function tests at different age groups in healthy Indian males.

Considerable attempts have been made to study the changes in lung function in man in different age groups using univariate statistical techniques in which the lung function tests were assumed to be independent of each other. Actually the lung function tests are well correlated with each other and, thus, the inferences drawn on the basis of univariate statistical analysis may be misleading due to the violation of the assumption of independence. On the other hand, simultaneous changes in lung function in man in different age groups cannot be tested using univariate statistical techniques. Keeping in view such shortcomings of the univariate statistical techniques, an attempt has been made in the present investigation to study simultaneous changes in some lung function tests [viz. vital capacity (VC), forced vital capacity (FVC), forced expiratory volume for one second (FEV1), expiratory reserve volume (ERV), inspiratory capacity (IC) and maximum voluntary ventilation (MVV)] at different age groups (viz. 21-25, 26-30, 31-35, 36-40, 41-45, 46-50, 51-55, 56-60 and 61-70 years) in healthy Indian males using multivariate statistical techniques (viz. Wilks' statistic (A) and Mahalanobis' D2 statistic) for drawing valid statistical inferences. It is concluded that remarkable significant changes take place in lung function after the age of forty years.

Adult↗
PubMed1982

Oxygen saturation during sleep in patients with spinal cord injury.

Sleep is associated with moderate or severe arterial desaturation in many disease states. This study was undertaken to evaluate whether hypoxemia during sleep was a significant problem in the spinal cord injured patient. Eleven patients with cervical or thoracic cord injury who had significant respiratory deficiency were evaluated. The mean age was 29.2 +/- 14. Vital capacity (VC) for the group revealed a mean of 43.1 +/- 18.1% of predicted, inspiratory capacity (IC) was 51.6 +/- 20.2% of predicted, and expiratory reserve volume (ERV) was 23.6 +/- 24.7% of predicted. In eight patients blood gases revealed a mean PO2 of 81.5 +/- 8.4 mmHg and PCO2 of 38.9 +/- 3.4 mmHg. Sleep screening studies were done using the Hewlett-Packard ear oximeter. They were studied for a mean of 2.6 +/- 1.1 hours. The initial O2 saturation was 96.6 +/- 1.6% and dropped to a mean of 90.6 +/- 6.4%. Only 1/11 reached saturation to less than 85% and 2/11 reached levels lower than 90%. Only age was significantly correlated with amount of desaturation (p less than .01). The level of the lesion, and % predicted ERV were not. One of the two patients who had hypoxemia with sleep had unilateral diaphragmatic paralysis. It is concluded that young quadriplegic patients with normal diaphragmatic function have no severe desaturation during sleep, but older patients and patients with some diaphragmatic dysfunction should be screened for sleep desaturation.

Adolescent↗
PubMed1997

Comparison of pulmonary function amongst Ladakhi, Delhi, Vanvasi and Siddi female athletes.

Lung functions were studied in contemporary healthy Indian female athletes of Ladakhi, Delhi, Vanvasi and Siddi origin training for running events of varying distances. The aim of the study was to compare the lung function in females belonging to these four groups to examine lung function in relation to ethnic and environmental factors. Vital Capacity (VC), Forced Vital Capacity (FVC), Forced Expiratory Volume in Ist second (FEV1), Expiratory Reserve Volume (ERV), and Inspiratory Capacity (IC) were recorded using conventional closed circuit spirometry. Maximum Voluntary Ventilation (MVV) was estimated by collecting expired air during deep and rapid breathing in a 100 liters meterological balloon for a period of 15 seconds and measuring its volume. It was found that Ladakhi females were having significantly higher VC, FVC and FEV1 values than their counterparts. However, there was no significant difference in MVV amongst Delhi, Siddi and Vanvasi young females. The average MVV of Ladakhi females was only significantly higher than Siddi females (P < 0.05).

Adolescent↗
PubMed1999

Effect of CPAP on breathlessness perception in healthy subjects during methacholine induced bronchoconstriction.

Application of continuous positive airway pressure (CPAP) in asthmatic patients decreases breathlessness (B). The effect of CPAP on induced bronchoconstriction was studied in healthy subjects. The changes in B were related to changes in lung function indices. In nine healthy volunteers, males aged 20-27 years, acute bronchoconstriction was induced by inhalation of 1 to 128 mg/ml methacholine (M). CPAP (0.5 kPa) was then applied for 1 min. It was followed by inhalation of albuterol. Forced expiratory volume in 1 s (FEV1) and vital capacity (VC) were measured by spirometry and end expiratory lung level (EELL), to derive inspiratory capacity (IC), by inductive plethysmography. B was assessed by Borg scale. After the maximal concentration of M, FEV1 decreased by 14% (p < 0.01) as compared to the control values and Borg score (BS) increased to 2.4 (p < 0.01). In 7 out of 9 subjects we found a significant (p < 0.05) correlation between the changes in FEV1 and BS. BS decreased during CPAP (p < 0.01) and it further decreased significantly after albuterol. There was no correlation between the changes in IC and FEV1 during bronchoconstriction, or between IC and BS during CPAP. In conclusion, in healthy subjects with induced bronchoconstriction CPAP decreased significantly BS, which was further improved by inhalation of albuterol. B was related to changes in FEV1 but not in IC.

Adult↗
PubMed1980

A consideration of nasal, pulmonary and cardio-vascular interdependance and nasal-pulmonary function studies.

Timed vital capacity of one second, peakflow, maximum breathing capacity (maximum voluntary ventilation), maximum middle half flow rate, total vital forced expiratory and inspiratory capacities, tidal and minute volume tested via the mouth and each "nose" separately for the diagnosis of nasal airway disturbance have proved to be valuable parameters of pulmonary function for the evaluation of the degree to which each nasal chamber "loads" the effort of breathing every breath in and out of the nose. Minimum "normal" ratios of nose to mouth finding have been determined. Calculations falling below these normals indicate strongly the presence of significant nasal airway disturbance. Especially is this true when repeated testing yields constant similar results.

Airway Obstruction↗
PubMed1995

Comparison of pulmonary function amongst Ladakhi, Delhi, Vanvasi and Siddi boy athletes.

Lung functions were studied in contemporary healthy boy athletes of Ladakhi, Delhi, Vanvasi and Siddi origin. As lung function are related to ethnic and environmental factors, the aim of the study was to compare the lung function in boys belonging to these four groups. Vital Capacity (VC), Forced Vital Capacity (FVC), Forced Expiratory Volume in 1st second (FEV1), Expiratory Reserve Volume (ERV) and Inspiratory Capacity (IC) were recorded using conventional closed circuit spirometry. Maximum Voluntary Ventilation (MVV) was estimated collecting expired air during deep and rapid breathing in a 100 litres meterological balloon for a period of 15 seconds and measuring its volume. It was found that Ladakhi boys were having significantly higher VC, FVC and FEV1 values than their counterparts. However, there was no significant difference in MVV amongst Ladakhi, Delhi, Vanvasi and Siddi boys. Our results suggest that size of the lung is governed by genetic, environmental and nutritional factors and confirm that physical training during growth may help in developing a greater endurance in respiratory muscles.

Adolescent↗
PubMed1994

A longitudinal study of pulmonary function tests during pregnancy.

The study deals with evaluation of pulmonary function status in fifty normal pregnant women tested monthly. The parameters studied were Vital Capacity (VC) Forced Vital Capacity (FVC) and Forced Expiratory Volume in 1st second (FEV1) using Vitalograph Spirometer; tidal volume (VT), inspiratory capacity (IC) and expiratory reserve volume (ERV) using Expirograph and resting minute ventilation (VE) using Tissot's spirometer. Control values were obtained in the same subject 8-10 weeks after delivery. The increase seen in VT, VE and IC was very highly significant. The small increment in frequency of respiration is significant and the declining trend observed in ERV is very highly significant. VC and FVC were maintained by the rise in IC and a concomitant fall in ERV. Rise in VC is attributed mainly to rise in VT than rise in frequency. The results suggest that though pulmonary function is altered during pregnancy, it is not compromised and hence does not induce any mechanical stress on the respiratory efficiency of the pregnant woman.

Adult↗
PubMed2001

Effects of hyperoxia on ventilatory limitation during exercise in advanced chronic obstructive pulmonary disease.

We studied interrelationships between exercise endurance, ventilatory demand, operational lung volumes, and dyspnea during acute hyperoxia in ventilatory-limited patients with advanced chronic obstructive pulmonary disease (COPD). Eleven patients with COPD (FEV(1.0) = 31 +/- 3% predicted, mean +/- SEM) and chronic respiratory failure (Pa(O(2)) 52 +/- 2 mm Hg, Pa(CO(2 ))48 +/- 2 mm Hg) breathed room air (RA) or 60% O(2) during two cycle exercise tests at 50% of their maximal exercise capacity, in randomized order. Endurance time (T(lim)), dyspnea intensity (Borg Scale), ventilation (V E), breathing pattern, dynamic inspiratory capacity (IC(dyn)), and gas exchange were compared. Pa(O(2)) at end-exercise was 46 +/- 3 and 245 +/- 10 mm Hg during RA and O(2), respectively. During O(2), T(lim) increased 4.7 +/- 1.4 min (p < 0.001); slopes of Borg, V E, V CO(2), and lactate over time fell (p < 0.05); slopes of Borg-V E, V E-V CO(2), V E-lactate were unchanged. At a standardized time near end-exercise, O(2) reduced dyspnea 2.0 +/- 0.5 Borg units, V CO(2) 0.06 +/- 0.03 L/min, V E 2.8 +/- 1.0 L/min, and breathing frequency 4.4 +/- 1.1 breaths/min (p < 0.05 each). IC(dyn) and inspiratory reserve volume (IRV) increased throughout exercise with O(2) (p < 0.05). Increased IC(dyn) was explained by the combination of increased resting IRV and decreased exercise breathing frequency (r(2) = 0.83, p < 0.0005). In conclusion, improved exercise endurance during hyperoxia was explained, in part, by a combination of reduced ventilatory demand, improved operational lung volumes, and dyspnea alleviation.

Aged↗
PubMed1985

Effects of paralysis with pancuronium on chest wall statics in awake humans.

The influence of tonic inspiratory muscle activity on the relaxation characteristics of the chest wall, rib cage (RC), and abdominal wall (ABW) has been investigated in four highly trained subjects. Chest wall shape and volume were estimated with magnetometers. Pleural pressure (Pes) and abdominal pressure were measured with esophageal and gastric balloons, respectively. Subjects were seated reclining 30 degrees from upright, and respiratory muscle weakness was produced by pancuronium bromide until RC inspiratory capacity was decreased to 60% of control. Only minor changes were observed for Konno-Mead relaxation characteristics (RC vs. ABW) between control and paralysis. Similarly, although RC relaxation curves (RC vs. Pes) during paralysis were significantly different from control (P less than 0.05), the changes were small and not consistent. The differences between paralysis-induced changes in resting end-expiratory position of the chest wall and helium-dilution functional residual capacity (FRC) suggested changes in volume of blood within the chest wall. We conclude that 1) although tonic inspiratory activity of chest wall muscles exists, it does not significantly affect the chest wall relaxation characteristics in trained subjects; 2) submaximal paralysis produced by pancuronium bromide is likely to modify either spinal attitude or the distribution of blood between extremities and the thorax; these effects may account for the changes in FRC in other studies.

Blood Volume↗
PubMed1993

Effect of priming dose of vecuronium on lung function in elderly patients.

We questioned whether the side effects outweighed the advantages of priming doses of nondepolarizing neuromuscular relaxants in awake patients. We have assessed lung function and clinical evidence of muscle weakness in 10 elderly patients, eight women and two men, aged 67-78 yr, ASA grade I or II, before and 3 min after a priming dose (0.01 mg/kg) of vecuronium. Forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), maximum midexpiratory flow rate (MMEF), peak expiratory flow rate (PEFR), inspiratory capacity (IC), functional residual capacity (FRC), expiratory reserve volume (ERV), residual volume (RV), slow vital capacity (SVC), and total lung capacity (TLC) were measured by using a Morgan transfer test machine and oxygen saturation (SpO2) was measured by pulse oximetry. All the patients developed ptosis, six had diplopia and were unable to perform the Valsalva maneuver for 10s, and four were unable to swallow or lift their head for > 4s, demonstrating significant muscle weakness. Significant reductions occurred in FVC, FEV1, FRC, ERV, SVC, and TLC. SpO2 decreased in 8 of 10 patients, and in 4 the decrease exceeded 4%. We conclude that priming with vecuronium 0.01 mg/kg in elderly patients causes significant impairment of lung function and a significant decrease in oxygen saturation.

Aged↗
PubMed2002

[Diaphragm electrical activation in COPD patients].

Several studies have demonstrated relatively moderate increase in Pdi during exhaustive exercise in COPD patients. The present study was designed to determine whether the small increase in Pdi is due to a central inhibition of respiratory drive, or an inability of the diaphragm to develop pressure. Diaphragm electrical activation (Edi) and transdiaphragmatic (Pdi) pressure were measured in 19 patients with severe COPD using an esophageal catheter. End-expiratory lung volume (EELV) was assessed by inspiratory capacity (IC) maneuvers. Maximal voluntary Edi (Edimax) was obtained during these maneuvers. EELV increased during exercise (p < 0.001) causing end-inspiratory lung volume to attain 98 +/- 5% of TLC at end-exercise. Pdi at rest was 8.4 +/- 2.6 cm H2O. Edi was 19 +/- 4% of Edimax at rest and increased progressively during exercise (p < 0.001) to reach 78 +/- 3% of Edimax at end-exercise. In conclusion, dynamic hyperinflation during exhaustive exercise in patients with COPD, reduces diaphragm pressure generating capacity, promoting near maximal levels of diaphragm activation without evidence of central inhibition.

Diaphragm↗
PubMed1994

Radical forequarter amputation with hemithoracectomy and free extended forearm flap: technical and physiologic considerations.

BACKGROUND: A radical forequarter amputation with partial chest wall resection (one to four ribs) has been reported for benign and malignant lesions involving the shoulder and chest wall region. Concerns about reconstruction and postoperative pulmonary function have previously limited more extensive chest wall resections. The current report describes the first case in which a complete unilateral anterior and posterior chest wall resection and pneumonectomy (hemithoracectomy) accompany a forequarter amputation. A novel reconstructive technique used the full circumference of the forearm tissue with an intact ulna as a free osseomyocutaneous flap. METHODS: In this case, a 21-year-old patient presented with an extensive recurrent desmoid tumor that involved the shoulder, brachial plexus, subclavian vein, and chest wall from the lateral sternal border to the midportion of the scapula and down to the eighth rib. The operative technique involved removal of the entire right hemithorax from the midline sternum to the transverse process posteriorly, down to the ninth rib inferiorly. Due to the absence of a rigid hemithorax, the uninvolved ipsilateral lung was also removed. The forearm flap was prepared before final separation of the specimen and division of the subclavian vessels. RESULTS: Postoperatively, the patient maintained excellent oxygenation without atelectasis or fever and was extubated on the 15th postoperative day. As expected after pneumonectomy, significant decreases from preoperative to immediate postoperative values were noted for the vital capacity (VC) (from 4.87 L to 1.29 L), forced 1-s expiratory volume (FEV1) (from 3.77 L to 1.02 L), and inspiratory capacity (IC) (3.33 l to 0.99 l). Rehabilitation included a specially designed external prosthesis to provide cosmesis and prevent scoliosis. By the 15th postoperative week the patient had returned to normal social and physical activities, with a gradual improvement in all respiratory parameters: VC 1.52 L, FEV1 1.29 L, IC 1.04 L. There has been no evidence of tumor recurrence at 1 year. CONCLUSIONS: This report provides evidence that a complete hemithoracectomy, pneumonectomy, and forequarter amputation can be safely performed for selective tumors involving the shoulder region with extensive chest wall invasion. Reconstruction may be achieved with an extended forearm osseomyocutaneous free flap with an excellent functional outcome.

Adult↗
PubMed1993

Estimation of ventilatory capacity during submaximal exercise.

There is presently no precise way to determine ventilatory capacity for a given individual during exercise; however, this information would be helpful in evaluating ventilatory reserve during exercise. Using schematic representations of maximal expiratory flow-volume curves and individual maximal expiratory flow-volume curves from four subjects, we describe a technique for estimating ventilatory capacity. In these subjects, we measured maximal expiratory flow-volume loops at rest and tidal flow-volume loops and inspiratory capacity (IC) during submaximal cycle ergometry. We also compared minute ventilation (VE) during submaximal exercise with calculated ventilatory maxima (VEmaxCal) and with maximal voluntary ventilation (MVV) to estimate ventilatory reserve. Using the schematic flow-volume curves, we demonstrated the theoretical effect of maximal expiratory flow and lung volume on ventilatory capacity and breathing pattern. In the subjects, we observed that the estimation of ventilatory reserve with use of VE/VEmaxCal was most helpful in indicating when subjects were approaching maximal expiratory flow over a large portion of tidal volume, especially at submaximal exercise levels where VE/VEmaxCal and VE/MVV differed the most. These data suggest that this technique may be useful in estimating ventilatory capacity, which could then be used to evaluate ventilatory reserve during exercise.

Adult↗
PubMed1989

Effect of immersion on lung capacities and volumes: implications for the densitometric estimation of relative body fat.

Immersion of 18 male subjects in water caused a 20.4% (787 ml) increase (P less than 0.05) in the mean inspiratory capacity (IC) whereas there were no changes (P greater than 0.05) in tidal volume (VT) and the frequency of respiration. All the means for the other pulmonary variables decreased (P less than 0.05) by varying amounts: total lung capacity (TLC) = 8.4% (599 ml), vital capacity (VC) = 5.5% (308 ml), functional residual capacity (FRC) = 42.6% (1386 ml), expiratory reserve volume (ERV) = 61.9% (1095 ml) and residual volume (RV) = 19.7% (292 ml). Variation of only the RV in the body density (BD) formula from which the percentage body fat (%BF) is estimated resulted in a significantly (P less than 0.05) lower mean of 15.2% BF for the RV in air (means = 1482 ml) compared with that of 17.1% BF for the RV in water (means = 1190 ml). All but one of the subjects exhibited a smaller RV in water than in air; the six largest differences were equivalent to 2.4-5.1% BF. These results indicate that the net effect of the hydrostatic pressure (decreases RV), pulmonary vascular engorgement (decreases RV) and diminished compliance (increases RV) is to reduce the ventilated RV. It is therefore advisable to measure the RV when the subject is immersed in order to minimize error in the determination of BD and hence the estimation of % BF.

Adipose Tissue↗
PubMed1980

Respiratory function during cervical and thoracic extradural analgesia in patients with normal lungs.

Lung volumes, expired gas volumes, tests of ventilatory capacity and blood-gas tensions were measured in women before and after induction of cervical or thoracic extradural analgesia using 2% mepivacaine. Inspiratory capacity, vital capacity, total lung capacity and FEV1 all decreased significantly 30 min after both cervical and thoracic extradural blocks. The changes observed during cervical block were significantly greater than those observed during thoracic extradural analgesia. Expiratory reserve volume and functional residual capacity decreased significantly after thoracic extradural block, but did not change after cervical extradural block. Reduction in expired minute volume was observed in the two groups. PaCO2 and alveolar-arterial oxygen tension difference increased, and PaO2 decreased significantly 25 min after both blocks. These results demonstrate that pulmonary ventilation is slightly impaired by the two blocks and to the same degree, but ventilatory reserve and capacity are markedly impaired by cervical extradural block.

Adult↗
PubMed1980

Inspiratory muscle force in normal subjects and patients with interstitial lung disease.

Measurements of the lowest mouth pressures developed during maximum static inspiratory efforts are related to the recoil force of the lung and occasionally are influenced by glottic closure. The measurement of minimal pleural pressures (P pl min) over the entire range of inspiratory capacity eliminates both problems and, in addition, provides a good estimate of the subject's cooperation. Using this technique, we have investigated the inspiratory muscle force in 120 healthy adults (60 men, 60 women) aged 21 to 76 years, and 15 healthy children (eight boys, seven girls) aged 7 to 13 years. Twelve patients with interstitial lung disease were studied for comparison. In the healthy adults, at any fixed (fractional) lung volume, P pl min increased, that is, became less negative with advancing age, both in males and females (all r greater than 0.56, p less than 0.001). This pattern was not modified after correction of the data for the static recoil pressure of the chest wall, indicating that the inspiratory muscle force actually decreases with age. In any age group, and after correction of lung volume for the difference in stature, the P pl min values in women were between 80 and 90% of the values found in men; moreover the children generated pressures that were as low as those developed by the younger adults. This is probably because women and children have a smaller thorax than men and are therefore able to generate low pressures, despite weaker muscles. When the reduction in lung volume was taken into account, the relationship between lung volume and P pl min was normal in the patients with interstitial lung disease. These patients showed a close relationship between the degree of lung volume restriction and the increase of the static recoil pressure of the lung at full inflation, suggesting that their thorax is normally compliant. It appears therefore that these patients have normal inspiratory muscle force, at least when they are not in an advanced stage of the disease.

Adolescent↗