Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Inspiratory Capacity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed1990

Effect of a deep breath on gas mixing and diffusion in the lung.

We examined the effect of a previous deep breath on both inert gas mixing and the single breath diffusing capacity (DLCOSB) during submaximal single breath maneuvers in normal subjects. Single breath washouts were performed either immediately after a deep breath or after breathing tidally for 10 min. Maneuvers consisted of inhaling test gas from functional residual capacity to 50% inspiratory capacity and, after either 0 or 6 s of breath holding, exhaling slowly back to residual volume. We measured the Fowler dead space, the Phase III slope of the alveolar plateau of the He washout (delta He/L), the amplitude of the cardiogenic oscillations (Oc), closing capacity, mixing efficiency (Emix) and DLCOSB using the three equation method. For maneuvers immediately after a deep breath we found that delta He/L was steeper and the Oc were larger for washouts with 6 s but not 0 s of breath holding, while Emix was significantly lower and DLCOSB significantly higher for both the 0 s and the 6 s breath holding maneuvers. We conclude that a deep breath increases DLCOSB but simultaneously also increases convective-dependent inhomogeneity in the lung.

Adult↗
PubMed1997

Contribution of vagal afferents to breathing pattern in rats with lung fibrosis.

In anesthestized male Wistar rats with bleomycin-induced lung fibrosis we examined the influence of lung vagal non-myelinated and myelinated afferents in setting breathing pattern. Fourteen days after intratracheal instillation of bleomycin, lung compliance, total lung capacity (TLC) and inspiratory capacity were reduced while functional residual capacity and residual volume were increased. Baseline tidal volume (VT) was decreased and frequency (fR) increased in the bleomycin treated rats compared with controls. Selective vagal C-fiber blockade did not affect fR or VT in any group. Vagotomy resulted in an increase in VT and decrease in fR in both groups with the percent increase in VT/TLC and decrease in fR being significantly greater in the bleomycin rats compared with controls. Vagotomy also attenuated the significantly elevated PCO2 in the bleomycin treated rats suggesting that bleomycin-induced alterations in breathing pattern contribute to blood gas abnormalities. We conclude that vagal myelinated afferents contribute to the rapid shallow breathing in bleomycin treated rats.

Animals↗
PubMed2003

Automated lung segmentation in X-ray computed tomography: development and evaluation of a heuristic threshold-based scheme.

RATIONALE AND OBJECTIVES: To develop and evaluate a reliable, fully-automated lung segmentation scheme for application in X-ray computed tomography. MATERIALS AND METHODS: The automated scheme was heuristically developed using a slice-based, pixel-value threshold and two sets of classification rules. Features used in the rules include size, circularity, and location. The segmentation scheme operates slice-by-slice and performs three key operations: (1) image preprocessing to remove background pixels, (2) computation and application of a pixel-value threshold to identify lung tissue, and (3) refinement of the initial segmented regions to prune incorrectly detected airways and separate fused right and left lungs. RESULTS: The performance of the automated segmentation scheme was evaluated using 101 computed tomography cases (91 thick slice, 10 thin slice scans). The 91 thick cases were pre- and post-surgery from 50 patients and were not independent. The automated scheme successfully segmented 94.0% of the 2,969 thick slice images and 97.6% of the 1,161 thin slice images. The mean difference of the total lung volumes calculated by the automated scheme and functional residual capacity plus 60% inspiratory capacity was -24.7 +/- 508.1 mL. The mean differences of the total lung volumes calculated by the automated scheme and an established, commonly used semi-automated scheme were 95.2 +/- 52.5 mL and -27.7 +/- 66.9 mL for the thick and thin slice cases, respectively. CONCLUSION: This simple, fully-automated lung segmentation scheme provides an objective tool to facilitate lung segmentation from computed tomography scans.

Image Processing, Computer-Assisted↗
PubMed2003

Pulmonary function 4 months after coronary artery bypass graft surgery.

The objective of this study was to describe the pulmonary function and pain 4 months after coronary artery bypass graft surgery. Twenty-five male patients performed pulmonary function tests before surgery, on the 4th postoperative day and 4 months after surgery. A severe reduction in pulmonary function was present after surgery. Four months postoperatively, the patients still showed a significant decrease (6-13% of preoperative values) in vital capacity (P<0.001), inspiratory capacity (P<0.001), forced expiratory volume in 1 s (P<0.001) peak expiratory flow rate (P<0.001), functional residual capacity (P=0.05) total lung capacity (P<0.001) and single-breath carbon monoxide diffusing capacity (P<0.01). Residual volume and single-breath carbon monoxide diffusing capacity per litre of alveolar volume had returned to the preoperative level. Four months postoperatively, the median values for sternotomy pain while taking a deep breath was 0.2 and while coughing 0.3 on a 10 cm visual analogue pain scale. In conclusion, a significant restrictive pulmonary impairment persisting up to 4 months into the postoperative period was found after CABG. Measured levels of pain were low and could not explain the impairment.

Aged↗
PubMed2005

Effect of salbutamol on lung function and chest wall volumes at rest and during exercise in COPD.

BACKGROUND: Inhaled bronchodilators can increase exercise capacity in chronic obstructive pulmonary disease (COPD) by reducing dynamic hyperinflation, but treatment is not always effective. This may reflect the degree to which the abdomen allows dynamic hyperinflation to occur. METHOD: A double blind, randomised, crossover trial of the effect of 5 mg nebulised salbutamol or saline on endurance exercise time was conducted in 18 patients with COPD of mean (SD) age 67.1 (6.3) years and mean (SD) forced expiratory volume in 1 second (FEV1) of 40.6 (15.0)% predicted. Breathing pattern, metabolic variables, dyspnoea intensity, and total and regional chest wall volumes were measured non-invasively by optoelectronic plethysmography (OEP) at rest and during exercise. RESULTS: Salbutamol increased FEV1, forced vital capacity (FVC) and inspiratory capacity and reduced functional residual capacity (FRC) and residual volume significantly. OEP showed the change in resting FRC to be mainly in the abdominal compartment. Although the mean (SE) end expiratory chest wall volume was 541 (118) ml lower (p<0.001) at the end of exercise, the endurance time was unchanged by the bronchodilator. Changes in resting lung volumes were smaller when exercise duration did not improve, but FEV1 still rose significantly after active drug. After the bronchodilator these patients tried to reduce the end expiratory lung volume when exercising, while those exercising longer continued to allow end expiratory abdominal wall volume to rise. The change to a more euvolumic breathing pattern was associated with a lower oxygen pulse and a significant fall in endurance time with higher isotime levels of dyspnoea. CONCLUSIONS: Nebulised salbutamol improved forced expiratory flow in most patients with COPD, but less hyper-nflated patients tried to reduce the abdominal compartmental volume after active treatment and this reduced their exercise capacity. Identifying these patients has important therapeutic implications, as does an understanding of the mechanisms that control chest wall muscle recruitment.

Aged↗
PubMed1979

Rib cage deformation during static inspiratory efforts.

Patterns of rib cage (RC) deformation were studied in six normal subjects during moderate static inspiratory efforts such that esophageal pressure (Pes) as an index of transthoracic pressure fell to between -30 and -60 cmH2O during each maneuver. At lung volumes below 50% inspiratory capacity (IC), static inspiratory efforts deformed RC to a more elliptical shape; RC lateral diameter became smaller and RC lateral diameter became larger. However, at high lung volumes (greater than 50% IC) the opposite change in RC dimensions occurred despite similar changes in Pes, i.e., the RC became more circular. These differences in RC deformation did not appear to be a possive consequence of increased lung volume because the RC could be voluntarily deformed to a more circular shape at low lung volume when a) subjects performed static inspiratory efforts mainly with their intercostal and accessory muscles rather than their diaphragm as judged by a smaller change in transdiaphragmatic pressure for the same Pes; or b) subjects statically contracted their diaphragm with it held in a relatively flattened configuration as assessed by a large abdominal AP dimension. We suggest that deformation of the RC during static inspiratory efforts is not as predictable as has previously been suggested but depends on the pattern of contraction and configuration of the respiratory muscles.

Adult↗
PubMed2001

Lung mechanics in individuals with spinal cord injury: effects of injury level and posture.

Individuals with spinal cord injury (SCI) exhibit reduced lung volumes and flow rates as a result of respiratory muscle weakness. These features have not, however, been investigated in relation to the combined effects of injury level and posture. Changes in forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), FEV(1)/FVC, forced expiratory flow at 50% vital capacity (FEF(50)), inspiratory capacity (IC), and expiratory reserve volume (ERV) were assessed by injury level in the seated and supine positions in 74 individuals with SCI. The main findings were 1) FVC, FEV(1), and IC increased with descending SCI level down to T(10), below which they tended to level off; 2) supine values of FVC and FEV(1) tended to be larger in the supine compared with the seated posture down to injury level T(1), caudad to which they were less than when seated; 3) IC increased proportionately more down to injury level L(1), below which it declined slightly and plateaued; 4) ERV was measurable even at high cervical injuries, was generally smaller in the supine position, reached peak values in both positions at T(10) injury level, and then rapidly declined at lower levels; 5) when subjects were separated according to current, former, and never smokers, only formerly smoking paraplegic individuals demonstrated spirometric values significantly less than paraplegic individuals who never smoked. Changes in spirometric measurements in SCI are dependent on injury level and posture. These findings support the concept that the increase in vital capacity in supine position is related to the effect of gravity on abdominal contents and increase in IC.

Adult↗
PubMed2001

Seasonal variations in respiratory system in healthy inhabitants of west Siberia.

The aim of this work was to investigate seasonal variations in oxygen consumption, ventilation, lung volumes and their relationships in healthy adult inhabitants of West Siberia. The investigations were performed in Novosibirsk. Thirty healthy male adult volunteers were studied 4 times during a year: in summer (mean monthly temperature +20 degrees C), autumn (+2 degrees C), winter (-18 degrees C), and spring (degrees C) under the same conditions in a room at rest. Oxyspirography, pneumotachography and the helium dilution method were used. Oxygen consumption (VO2), breathing frequency, vital capacity (VC) and inspiratory capacity were adjusted to be the same during the year. Minute ventilation (Ve), VO2-Ve ratio, residual volume (RV) and expiratory reserve volume (ERV) to RV ratio had dynamics concurrent with seasonal temperature dynamics. Tidal volume, ERV, functional residual capacity, forced 1-s expired volume (FEV1) and FEV1/VC also changed, but their dynamics were different from the previous parameters. The minimum value of these parameters was found in the spring and the maximum--in the autumn, or summer and autumn. Correlations between respiratory parameters also changed during the year. We conclude that oxygen consumption is provided by reorganisation of pulmonary tissue in winter.

Adult↗
PubMed2002

[Ventilatory mechanics and alveolo-capillary diffusion in diabetes].

In order to appreciate the repercussion of diabetes on the respiratory function, we measured the pulmonary volumes, the ventilatory flows, the airways resistances (Raw) and the diffusing capacity for the carbon monoxide (DLCO) of 49 diabetes distributed into 27 IDDM and 22 NIDDM aged from 15 to 56 years, compared to 31 control subjects. We found a significant decrease in the total pulmonary capacity (TCL), the vital capacity (VC), the inspiratory capacity (IC), the ventilatory flows and the DLCO. The decrease of the VC and the FEV1 will be more marked in the IDDM. The decrease of the DLCO will be more pronounced within masculine sex, it seems to be correlated with the duration of diabetes and more impaired if a diabetic nephropathy is associated especially in IDDM. Our results suggest that in the diabetes evolution, the lung is among the target organs in the degenerative complications. The respiratory tests reflect the pulmonary reach in the diabetes and provides important perspectives in the following.

Adolescent↗
PubMed2005

[Effect of lung transplantation on pulmonary function in 5 patients with chronic obstructive pulmonary disease].

OBJECTIVE: To investigate the therapeutic effect of lung transplantation on pathophysiology and pulmonary function in chronic obstructive pulmonary disease (COPD) patients. METHODS: Five male COPD (grade IV) patients, aged 51 to 63 yr, were enrolled in the study. The patients underwent pulmonary function tests and the following measurements 2 weeks before and 2 months after the operation. The measured parameters included forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), FEV(1)/FVC, maximal ventilatory volume (MVV), residual volume (RV), total lung capacity (TLC), RV/TLC, inspiratory capacity (IC), thoracic gas volume (TGV), peak expiratory flow (PEF), total airway resistance (R(aw)total), diffusion capacity for CO of lung (D(L)CO), diffusion capacity for CO of lung/alveolar volume (D(L)CO/V(A)), 6 minute walk distance (6MWD), partial pressure of oxygen in arterial blood (PaO(2)), alveolar-artery oxygen gradient [P((A-a))O(2)], oxygen saturation in arterial blood (SaO(2)), partial pressure of carbon dioxide in arterial blood (PaCO(2)) and mean pulmonary arterial pressure (mPAP). RESULTS: The measured parameters before vs after the operation were as follows: MVV (23.6 +/- 5.8) vs (71.6 +/- 21.8) L, FEV(1) (0.68 +/- 0.21) vs (1.85 +/- 0.46) L, FEV(1)/FVC (37.4 +/- 8.3)% vs (75.6 +/- 13.9)%, PaO(2) (60.0 +/- 9.1) vs (86.2 +/- 2.9) mm Hg (1 mm Hg = 0.133 kPa), SaO(2) (90.0 +/- 4.6)% vs (96.8 +/- 0.5)% and mPAP (31.2 +/- 5.5) vs (16.6 +/- 1.8) mm Hg; all were significantly improved in the 5 cases (all P < 0.05); IC [(1.16 +/- 0.26) vs (1.83 +/- 0.35) L], TGV [(6.52 +/- 0.27) vs (4.52 +/- 0.29) L], RV [(5.12 +/- 0.39) vs (3.20 +/- 0.32) L], RV/TLC [(71.0 +/- 5.6)% vs (51.3 +/- 2.5)%] and R(aw) total [(6.62 +/- 0.99) vs (2.48 +/- 0.87) cm H2O.L(-1).s(-1)] were significantly improved in 3 of the 5 patients (all P < 0.05); PEF [(1.65 +/- 0.40) vs (3.92 +/- 1.63) L/s], D(L)CO [(8.5 +/- 3.0) vs (21.0 +/- 6.2) ml.min(-1).mm Hg(-1)] and 6MWD [(46.8 +/- 14.7) vs (246.8 +/- 51.9) m] were significantly increased in 4 of the 5 patients (all P < 0.05). FVC [(1.85 +/- 0.40) vs (2.45 +/- 0.49) L], TLC [(7.19 +/- 0.15) vs (6.26 +/- 0.73) L], D(L)CO/V(A) [(2.90 +/- 1.50) vs (5.41 +/- 0.87) L.min(-1).mm Hg(-1)], P((A-a))O(2) [(37.6 +/- 16.3) vs (17.8 +/- 6.3) mm Hg] and PaCO(2) [(44.6 +/- 7.7) vs (37.4 +/- 3.4) mm Hg] were also improved but did not reach significance (all P > 0.05). CONCLUSION: Spirometry, airway resistance, residual capacity, diffusion capacity, exercise tolerance and gas exchange were improved remarkably after lung transplantation in COPD patients.

Forced Expiratory Volume↗
PubMedDate not supplied

Comparison of four methods for calculating the total lung capacity measured by body plethysmography.

Static lung volumes were measured plethysmographically one hour apart in healthy subjects (n = 14) and in patients with chronic pulmonary disorders of various etiologies (n = 25). The total lung capacity (TLC) obtained from paired measurements of functional residual capacity (FRC) and inspiratory capacity (IC) was calculated according to the four following methods: 1) average FRC plus the largest IC, 2) average FRC plus the average IC, 3) largest sum of FRC and corresponding IC, and 4) average of individual FRC and IC sums. The data, analysed for average values and for reproducibility in the group as a whole and in the healthy subjects and patients separately indicate that: a) For the group as a whole the largest average TLC values were found with method 3 followed by methods 4 and 1. The differences were statistically significant for all comparisons but one (method 1 vs method 4). A similar pattern was found for the healthy subjects and patients separately. b) For the group as a whole, the one hour reproducibility tended to be worse from method 1 through method 4 but the intermethod differences were not statistically significant. For the healthy subjects, the reproducibility tended to be better for methods 3 and 4 and for the patients this was the case for methods 1 and 2. The average reproducibiltiy of methods 1 and 2 was similar for both the healthy and patient groups and these methods seemed more suitable for TLC calculations. Because it is more widely employed, method 1 is recommended.

Adolescent↗
PubMed1993

Cardiopulmonary bypass significantly reduces surfactant activity in children.

Lung injury remains an important problem after cardiopulmonary bypass. The contribution of altered surfactant concentration or activity to pulmonary dysfunction after cardiopulmonary bypass is unclear. Recent evidence indicates that alveolar surfactant exists in specific aggregate forms that differ with respect to density, phospholipid composition, and function. A transition from surface active, higher density, large aggregates of surfactant to lower density, small aggregates that possess reduced surface activity has been demonstrated after experimental lung injury. The purpose of the present study was to examine surfactant aggregate fractions before and after bypass in children. Twelve acyanotic patients, aged 2 to 12 years, underwent intraoperative pulmonary function testing followed by bronchoalveolar lavage before incision and approximately 1 hour after termination of cardiopulmonary bypass. Saturated phosphatidylcholine pool sizes and total protein content of the small- and large-aggregate fractions of bronchoalveolar lavage fluid were determined. One hour after termination of cardiopulmonary bypass, the ratio of saturated phosphatidylcholine in small-aggregate as compared with that in large-aggregate fractions increased (mean +/- standard error) from 0.19 +/- 0.03 to 0.37 +/- 0.07 (p < 0.02), as did the ratio of saturated phosphatidylcholine to protein in the small-aggregate fraction (from 0.04 +/- 0.01 to 0.08 +/- 0.02, p < 0.05). Reductions in forced vital capacity (-19% +/- 5%), inspiratory capacity (-15% +/- 3%), and small airway flow rates (-32% +/- 6%) were also observed after bypass. These changes were accompanied by a fivefold increase in alveolar polymorphonuclear leukocyte content. The present study suggests that cardiopulmonary bypass of moderate duration in relatively healthy children is associated with surfactant changes that are similar in type and magnitude to those observed in experimental lung injury.

Bronchoalveolar Lavage Fluid↗
PubMed1987

Activation of the inspiratory intercostal muscles by electrical stimulation of the spinal cord.

Electrical stimulation of the spinal cord was evaluated as a method of activating the inspiratory intercostal muscles. Studies were performed in anesthetized dogs after hyperventilation-induced apnea. A stainless steel electrode, rubberized along its entire length except for 2 to 3 mm at the distal tip, was introduced epidurally onto the dorsal surface of the thoracic spinal cord. Stimulating electrodes were also placed in each hemidiaphragm. Intercostal electromyograms, inspired volume, and thoracoabdominal movements were monitored. The inspiratory capacity was determined in each animal as the volume required to achieve an airway pressure of +25 cm H2O during passive lung inflation. Spinal cord stimulation at the T2-T3 spinal level resulted in maximal inspired volume generation and electrical activation of the parasternal, external, and internal intercostal muscles of the upper and midrib cage regions as determined by electromyograms. Intrathoracic pressure swings increased progressively with increasing stimulus amplitude and frequency until plateaus were reached at 6 mA and 40 Hz, respectively. Postphrenicotomy spinal cord stimulation resulted in expansion of the rib cage and reduction in circumference of the abdominal compartment. Inspired volumes during spinal cord stimulation were 537 +/- 49 ml (prephrenicotomy, prone), 347 +/- 19.6 ml (postphrenicotomy, prone), and 303 +/- 30.6 ml (postphrenicotomy, supine). Bilateral diaphragm activation alone resulted in inspired volumes of 404 +/- 39 ml. Combined diaphragm and postphrenicotomy spinal cord stimulation (supine) resulted in an inspired volume of 712 +/- 72 ml, which approximated the inspiratory capacity (803 +/- 35 ml). Our results suggest that spinal cord stimulation may be a useful physiologic and clinical tool to produce coordinated contraction of the inspiratory intercostal muscles.

Animals↗
PubMed2001

Breathing pattern and gas exchange at peak exercise in COPD patients with and without tidal flow limitation at rest.

Expiratory flow limitation (FL) at rest is frequently present in chronic obstructive pulmonary disease (COPD) patients. It promotes dynamic hyperinflation with a consequent decrease in inspiratory capacity (IC). Since in COPD resting IC is strongly correlated with exercise tolerance, this study hypothesized that this is due to limitation of the maximal tidal volume (VT,max) during exercise by the reduced IC. The present study investigated the role of tidal FL at rest on: 1) the relationship of resting IC to VT,max; and 2) on gas exchange during peak exercise in COPD patients. Fifty-two stable COPD patients were studied at rest, using the negative expiratory pressure technique to assess the presence of FL, and during incremental symptom-limited cycling exercise to evaluate exercise performance. At rest, FL was present in 29 patients. In the 52 patients, a close relationship of VT,max to IC was found using non-normalized values (r=0.77; p < 0.0001), and stepwise regression analysis selected IC as the only significant predictor of VT,max. Subgroup analysis showed that this was also the case for patients both with and without FL (r=0.70 and 0.76, respectively). In addition, in FL patients there was an increase (p < 0.002) in arterial carbon dioxide partial pressure at peak exercise, mainly due to a relatively low VT,max and consequent increase in the physiological dead space (VD)/VT ratio. The arterial oxygen partial pressure also decreased at peak exercise in the FL patients (p < 0.05). In conclusion, in chronic obstructive pulmonary disease patients the maximal tidal volume, and hence maximal oxygen consumption, are closely related to the reduced inspiratory capacity. The flow limited patients also exhibit a significant increase in arterial carbon dioxide partial pressure and a decrease in arterial oxygen partial pressure during peak exercise.

Aged↗
PubMed2003

[Effect of ipratropium bromide on lung dynamic hyperinflation in patients with chronic obstructive lung disease].

BACKGROUND: The six minute walk test (6 MW) elicits dynamic hyperinflation (DH) in severe COPD patients, which can be evaluated by reductions in inspiratory capacity (IC). Although IC is currently used to determine the effects of bronchodilators on DH during exercise tests on a cycle ergometer, its usefulness during a walking test has not been evaluated. AIM: To study the acute effects of ipratropium bromide (IB) on forced expiratory volume at l second (FEV1) and IC at rest and on DH during exercise assessed by the 6 MW. SUBJECTS AND METHODS: Fifteen stable COPD patients were randomly allocated in a double-blind, placebo-controlled, crossover fashion to 2 treatment periods using a single dose of nebulized IB 500 mg or placebo. Spirometry, including IC, and 6 MW were measured at baseline and after IB and placebo. IC was also measured 15 min after exercise. Dyspnea, oxygen saturation (SpO2) and heart rate were assessed at the end of exercise. RESULTS: After IB, 8/15 patients exhibited a clinically significant increase in IC (> or = 10% predicted). A similar increase in FEV1 was observed in only one patient. No changes were observed with placebo. A significant increase in 6 MW from baseline (p = 0.007) was found after IB (45 +/- 14 m) compared to placebo (0.5 +/- 9 m), whereas dyspnea was significantly lower. Inspiratory capacity fell after 6 MW with both treatments, but it reached their baseline values at 15 min after exercise only with IB. CONCLUSIONS: Our results demonstrate that IC provides additional information to conventional spirometry on the acute effects of bronchodilators and confirm its value to assess DH during a walking test.

Aged↗
PubMed1982

Anaesthetic considerations in patients with muscular dystrophy undergoing spinal fusion and Harrington rod insertion.

Charts of nine patients with Duchenne and one with Becker's muscular dystrophy who had undergone spinal fusion and Harrington rod insertion for scoliosis were reviewed retrospectively. The mean age was 15 years and mean angle of scoliosis was 69 degrees. Preoperative pulmonary function studies showed a restrictive defect with a mean vital capacity of 1.3 +/- 0.69 litres, 35 +/- 20 per cent of predicted value, 33 +/- 20 ml . kg-1 and a mean inspiratory capacity of 0.99 +/- 0.5 litres, 23 +/- 13 ml . kg-1. There were no anaesthetic complications during operation and obstructive cardiomyopathy, hyperpyrexia, hyperkalaemia and rhabdomyolysis were not problems. Succinylcholine was avoided. One patient developed an arrhythmia postoperatively and one patient whose postoperative problems included tracheostomy, pneumonia and sepsis could not be weaned from the ventilator and died 11 weeks after operation. As assessing risk and survival of the operation depends on objective pulmonary function, a vital capacity of at least 20 ml . kg-1 in the range of 30 per cent of predicted volume with an inspiratory capacity of at least 15 ml . kg-1 would appear to be adequate in patients with muscular dystrophy requiring Harrington rod insertion. Other factors including the rapidity of progression of the muscular disease, other respiratory and cardiovascular problems, and disease such as obesity should also be considered.

Adolescent↗
PubMed1997

[Respiration mechanics in tetraplegia].

Patients with quadriplegia due to transection of the lower cervical cord show, on spirographic examination, a marked decrease in vital capacity and its two components, i.e. inspiratory capacity (i.c.) and expiratory reserve volume (ERV). The loss of IC results partly from the decreased inspiratory muscle strength consecutive to the intercostal muscle paralysis but mostly from a reduction in the distensibility of the lungs and the rib cage. The reduction in ERV is related to the paralysis of all the well-recognized muscles of expiration (abdominals, interosseous internal intercostals); however, the clavicular portion of the pectoralis major allows these patients to maintain a small ERV.

Elasticity↗