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PubMed1997

Evaluation of pulmonary ventilation and diaphragmatic movement in idiopathic scoliosis using radioaerosol ventilation scintigraphy.

Regional distribution of lung ventilation and diaphragmatic movement were evaluated using a non-invasive scintigraphic method in patients with idiopathic scoliosis. Twenty-four non-smoking patients aged 20 +/- 9 years (mean +/- S.D.), all with a right convex dorsal curve (mean Cobb's angle of 65.1 +/- 26.4 degrees), underwent lung ventilation scintigraphy after inhalation of 99Tcm-labelled human albumin microspheres. The distribution of the inhaled aerosol was assessed and scored based on four scintigraphic patterns, ranging from homogeneous distribution (score = 1) to diffuse severe hypoventilation (score = 4). Diaphragmatic movement, evaluated in 11 of the 24 patients, was assessed using an index (DM-Index) computed for each hemi-diaphragm by the normalization and subtraction of two digital scans obtained during maximal inspiration and expiration respectively. The left lung, situated on the concave side of the scoliotic curve, showed a more uneven distribution of ventilation (scintigraphic score: 2.62 +/- 1.17 vs 1.50 +/- 1.02, P < 0.01) and a reduced hemi-diaphragm movement (DM-Index: 29.2 +/- 4.0 vs 35.9 +/- 2.9, P < 0.001). A significant inverse correlation was found between Cobb's angle and both the right and left DM-Index (r = -0.82 and -0.66 respectively). In a stepwise multiple-regression analysis, the scintigraphic score correlated significantly with the functional index of distribution of inspired gas (IDI) derived from the multiple-breath nitrogen washout curve (P = 0.02). We conclude that lung ventilation scintigraphy provides information on the regional distribution of ventilation and on diaphragmatic movement in idiopathic scoliosis. The pulmonary function derangements in scoliotic patients were mainly localized in the lung on the concave side of the scoliotic curve and were related to the severity of the spinal curvature.

Adult↗
PubMed1991

Pulmonary function and pleural fibrosis: quantitative relationships with an integrative index of pleural abnormalities.

Pleural fibrosis due to asbestos exposure was fully appreciated considerably later than pulmonary interstitial fibrosis due to similar exposure. This is well exemplified by the fact that pleura face on was included in the International Labour Office's International Classification of Radiographs of Pneumoconioses only in the last revision of the Classification. The functional relevance of pleural fibrosis, in particular circumscribed pleural fibrosis, has remained controversial. Since pleural fibrosis can occur at various sites (diaphragmatic plaques, chest wall in profile and face on, mediastinal) and can be of different thickness and extent, a comprehensive integrative assessment of pleural fibrosis was undertaken in order to permit a quantitative study of relationships between pleural fibrosis and pulmonary function. This approach was used for chest X-ray films of 1,584 asbestos insulation workers examined (1981-1983); 1,185 (75%) had pleural fibrosis. The distribution pattern of the integrative pleural index was found to be different in the subgroup with circumscribed (n = 975) from that with diffuse (n = 197) pleural fibrosis, with a higher profusion of high INDEX values in the latter. Stepwise regression analysis indicated that there was a significant inverse relationship between forced vital capacity (FVC) and the integrative index of pleural fibrosis in the subgroup with circumscribed pleural fibrosis. In the subgroup with diffuse pleural fibrosis, the obliteration of costophrenic angle(s), even with pleural fibrosis of limited extent, resulted in marked decrement in FVC% predicted; higher values of INDEX did not result in additional significant reductions of FVC. In those with both parenchymal and pleural abnormalities (n = 862) the pleural index was found to make a significant contribution, independent of that of parenchymal abnormalities, to decrements of FVC. Since pleural fibrosis has gradually become the predominant radiologically detectable abnormality in asbestos exposed workers, establishing its quantifiable functional relevance is useful.

Adult↗
PubMed1994

Respiratory muscle rest using nasal BiPAP ventilation in patients with stable severe COPD.

To more systematically evaluate the effect of respiratory muscle rest on indices of ventilatory function, nine outpatients with stable, severe COPD were treated with nasal pressure-support ventilation delivered via a nasal ventilatory support system (BiPAP, Respironics, Inc) for 2 h a day for 5 consecutive days. An additional eight control patients were treated with sham-BiPAP. Maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), maximum voluntary ventilation (MVV), arterial blood gas values, Borg dyspnea score, dyspnea-associated functional impairment scales, and distance walked in 6 min were measured in subjects prior to and following the week-long trial. Nasal BiPAP produced a 66.3 +/- 6 percent reduction in peak integrated diaphragmatic electromyographic (EMG) activity. There were no statistically significant changes in MIP, MEP, MVV, arterial pH, PaCO2, or PaO2 or in objective measures of functional impairment from dyspnea in either group after ventilator or sham treatment. However, nasal BiPAP reduced the Borg category score during resting, spontaneous breathing from 2.0 +/- 0.4 to 0.7 +/- 0.3 (p < 0.01) after 5 days of treatment. In contrast, sham BiPAP-treated patients had no change in their dyspnea score, which was 1.8 +/- 0.4 and 1.3 +/- 0.4 before and after sham treatment, respectively. Nasal BiPAP also increased distance walked in 6 min from 780 +/- 155 to 888 +/- 151 ft (p < 0.01) (23,400 +/- 4,650 to 26,640 +/- 4,530 cm) (p < 0.01), whereas sham-BiPAP had no effect (768 +/- 96 and 762 +/- 106 ft [23,040 +/- 2,880 and 22,860 +/- 3,180 cm]) before and after sham treatment, respectively). In conclusion, these results indicate that nasal pressure-support ventilation, delivered via nasal BiPAP, improves exercise capacity and reduces dyspnea over the short term in selected outpatients with stable severe COPD. Whether such short-term improvement can be sustained merits further study.

Activities of Daily Living↗
PubMed1977

Acquired eventration of the diaphragm--results of surgery.

Results of surgical repair of acquired diaphragmatic eventration are reported. The series consists of nine adult patients studied pre- and postoperatively with clinical, radiological and lung function investigations. The repair was performed in all cases by a thoracic approach and plication of the diaphragm. The operative procedure was well tolerated in all cases. On follow-up seven patients were found to be improved and in two transient or no improvement occurred. Subjectively, gastrointestinal symptoms were alleviated most often by the operation. Radiological studies showed that although the immediate postoperative position of the diaphragm was very good in all cases, the diaphragm began to stretch and elevate gradually during the first year. In one case rupture of the repaired diaphragm developed 2 years after plication. Reoperation was performed with success. In one case the anatomical end result was no better than before the repair, in the others it was partially or completely improved. Plate atelectasis was observed no longer after the operation. Preoperative lung function studies showed a slight to moderate restrictive defect in 8 cases and a marked one in one case. 37% of the total lung perfusion was distributed to the affected side. On the average no significant changes could be found between the pre- and postoperative values.

Adult↗
PubMed1976

Long-term follow-up of patients with congenital diaphragmatic hernia.

A long-term follow-up was carried out on 30 patients who had congenital diaphragmatic hernias operated on over a 21-yr period. The review took the form of clinical examination, chest x-rays, pulmonary function tests, and lung scans. Lungs that were hypoplastic at birth remained underdeveloped as judged by pulmonary function tests and hypoperfusion on lung scan; however, children who survived birth6 and operative repair went on to live normal lives through the period studied. There was some suggestion from pulmonary function tests and lung scans that in the older group a preemphysematous state may exist but this was asymptomatic. There was no evidence of increased susceptibility to respiratory infection in the group. Ten per cent of the children were mentally retarded, evidently from hypoxia after birth.

Adolescent↗
PubMed1988

Bilateral diaphragmatic paralysis: clinical spectrum, prognosis, and diagnostic approach.

In a retrospective review of the clinical course of five patients with nontrauma-related bilateral diaphragmatic paralysis, we found that the diagnosis is generally delayed (median delay: two years) in the presence of moderate to severe respiratory insufficiencies. Orthopnea out of proportion to the underlying cardiopulmonary status and thoracoabdominal paradoxus in the supine position are the clues to the diagnosis. Pulmonary function tests showed a typical restrictive ventilatory defect, and arterial blood gas showed chronic respiratory acidosis. Failure to recognize the diaphragmatic impairment led to cardiopulmonary decompensations such as cor pulmonale and acute respiratory failure. However, with the institution of appropriate therapy, adverse effects resolved and all five patients are alive and continue to lead independent lives. We conclude that nontrauma-related bilateral diaphragmatic paralysis is an underrecognized and underdiagnosed condition. The results also indicate that early diagnosis and treatment can minimize morbidity and mortality, and that excellent long-term, good-quality survival can be expected.

Aged↗
PubMed1983

Changes in rate of relaxation of sniffs with diaphragmatic fatigue in humans.

The rate of relaxation of the diaphragm after stimulated (4 subjects) and voluntary (8 subjects) contractions was compared in normal young men. Stimulated contractions were induced by supramaximal unilateral phrenic nerve stimulation and voluntary contractions by short, sharp sniffs of varying tensions against an occluded airway. The rate of relaxation of the diaphragm was calculated from the rate of decline of transdiaphragmatic pressure (Pdi). In both conditions the maximum relaxation rate (MRR) was proportional to the peak transdiaphragmatic pressure (Pdi), whereas the time constant (tau) of the later exponential decline in Pdi was independent of Pdi. The mean +/- SE rate constant of relaxation (MRR/Pdi) was 0.0078 +/- 0.0002 ms-1 and the mean tau was 57 +/- 3.8 ms for stimulated contractions. The rate of relaxation after sniffs was not different, and it was not affected by either the lung volume at which occluded sniffs were performed (in the range of residual volume to functional residual capacity + 1 liter) or by the relative contribution gastric pressure made to Pdi. After diaphragmatic fatigue was induced by inspiring against a high alinear resistance there was a decrease in relaxation rate. In the 1st min postfatigue MRR/Pdi decreased (0.0063 +/- 0.0003 ms-1; P less than 0.005) and tau increased (83 +/- 5 ms; P less than 0.005). Both values returned to prefatigue levels within 5 min of the end of the studies. We conclude that the sniff may prove to be clinically useful in the detection of diaphragmatic fatigue.

Adult↗
PubMed1999

Neuralgic amyotrophy with phrenic nerve involvement.

Phrenic nerve involvement is a rare feature in patients with neuralgic amyotrophy (Parsonage-Turner syndrome). We report four patients who initially presented with severe dyspnea in the absence of lung disease. All patients had a history of infectious disease or surgery and of pain of sudden onset in the shoulder region. Weakness of the proximal arm was observed in only one. Radiographic and pulmonary function studies, phrenic nerve conduction studies, and needle electromyogram (EMG) of the diaphragm documented diaphragmatic paralysis which was unilateral in one patient, bilateral in two patients, and recurrent on alternating sides in another one. Follow-up studies remained abnormal for up to 4 years. Neuralgic amyotrophy with phrenic nerve involvement should be considered in patients presenting with severe, unexplained dyspnea of sudden onset.

Aged↗
PubMed2003

Computing oxygen-enhanced ventilation maps using correlation analysis.

Correlation maps of oxygen-enhanced ventilation were obtained in nine healthy volunteers using complete and selected image series. The complete series included all images acquired with the subjects alternately inhaling room air and 100% oxygen. The selected series were the subsets of the complete series and included only co-registered images that showed matched diaphragmatic position at maximal expiration. Cross-correlation was computed between the time response function of each pixel and the input function representing the alternation between periods of room air and 100% oxygen inhalation. The confidence level for the correlation analysis was set to 0.01. Pulmonary parenchymal anatomy was consistently reproduced throughout the lung, even in anterior slices where published data have reported correlation problems. The overall average correlation coefficient was 0.66 +/- 0.07 for the complete series and 0.75 +/- 0.08 for the selected series. It was concluded that correlation analysis could be used to reconstruct qualitative oxygen-enhanced ventilation maps.

Adult↗
PubMed1985

Extracardiac left to right shunt in a patient with biventricular postinfarction rupture and pseudoaneurysm.

A 68 year old man had a diaphragmatic myocardial infarction and 9 months later was admitted with severe congestive heart failure (functional class IV). Cardiac catheterization demonstrated a postinfarction pseudoaneurysm. Because of a massive left to right shunt (pulmonary to systemic flow ratio = 2.7), concomitant rupture of the ventricular septum was suspected. At surgery the pseudoaneurysm communicated with the right ventricle through two different orifices and with the left ventricle through another ostium. The ventricular septum was intact. Therefore, the shunt was extracardiac through the pseudoaneurysm (left ventricle----pseudoaneurysm----right ventricle). The unique combination of lesions allowed the patient to survive. The false aneurysm was excised and primary repair was performed in the orifices of the right and left ventricular walls. The postoperative course was uneventful and 10 months later the patient was in functional class I.

Aged↗
PubMed2001

Free radical-induced contractile protein dysfunction in endotoxin-induced sepsis.

Recent studies have indicated that sepsis is associated with enhanced generation of several free-radical species (nitric oxide [NO], superoxide, hydrogen peroxide) in skeletal muscle. It is also known that this enhanced free-radical generation results in reductions in skeletal muscle force-generating capacity, but the precise mechanism(s) by which free radicals exert this effect in sepsis has not been determined. We postulated that free radicals might react directly with the contractile proteins in this condition, altering contractile protein force-generating capacity. To test this theory, we compared the force generation of single Triton-skinned diaphragmatic fibers (Triton skinning exposes the contractile apparatus, permitting direct assessment of contractile protein function) from the following groups of rats: (1) control animals; (2) endotoxin-treated animal; (3) animals given endotoxin plus polyethylene glycol- superoxide dismutase (PEG-SOD), a superoxide scavenger; (4) animals given endotoxin plus N(omega)-nitro-L-arginine methylester (L-NAME), a NO synthase inhibitor; (5 ) animals given only PEG-SOD or L-NAME; and (6 ) animals given endotoxin plus denatured PEG-SOD. We found that endotoxin administration produced both a reduction in the maximum force-generating capacity (Fmax) (i.e., a decrease in Fmax) of muscle fibers and a reduction in fiber calcium sensitivity (i.e., an increase in the Ca2+ concentration required to produce half-maximal activation [Ca50]). L-NAME and PEG-SOD administration preserved Fmax and Ca50 in endotoxin-treated animals; neither drug affected these parameters in non-endotoxin treated animals. Denatured PEG-SOD failed to inhibit endotoxin-related alterations in contractile protein function. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of skinned fibers from endotoxin-treated animals revealed a selective depletion of several proteins; administration of L-NAME or PEG-SOD to endotoxin-treated animals prevented this protein depletion, paralleling the effect of these two agents to prevent a reduction in contractile protein force-generating capacity. These data indicate that free radicals (superoxide, NO, or daughter species of these radicals) play a central role in altering skeletal muscle contractile protein force-generating capacity in endotoxin-induced sepsis.

Animals↗
PubMed1990

Diaphragmatic resection in association with right hepatectomy.

Ten cases of combined diaphragmatic and hepatic resection for tumours involving both structures are described. A complete work-up, including ultrasonography and computed tomography, usually can predict potential direct spread to the diaphragm. Up to 50% of the diaphragm can be excised and reconstructed without the need for prosthetic mesh or tissue transfer. Diaphragmatic resection does not appear to cause long-term postoperative morbidity. Diaphragmatic invasion by primary or secondary tumours does not preclude resection for cure. Pulmonary function studies are not necessary if there is no serious pre-existing lung disease.

Adult↗
PubMed1991

[Long-term outcome of congenital diaphragmatic hernia. A study of 17 patients].

In order to better define the outcome of patients with neonatal congenital diaphragmatic hernia (CDH), 17 patients between 3 and 19 years of age, among 34 survivors from 100 CDH have been re-examined clinically. All had a lung radiography, lung function studies, and radionuclide (Technetium 99m, Xenon 133) lung scans. Three patients suffered from asthma, 2 had recurrent bronchitis, 4 poor tolerance to effort, 3 gastrooesophageal regurgitation leading to endobrachyoesophagus and oesophagitis in one, 3 had scoliosis. Lung scans demonstrated hypoperfusion of the herniated side (less than 40%) in 6 patients. Chest films showed hypovascularisation on the herniated side. Lung function studies, performed in 4 of these 6 patients, showed a restrictive syndrome in 1 patient. Our results confirm those in the literature: perfusion is more altered than ventilation. Chest films at one year of age, completed if necessary by radionuclide lung scans, allow identification of children who have important pulmonary hypoplasia. These children need a regular follow-up: respiratory, digestive and orthopedic complications must be treated in order to preserve the respiratory function in adulthood.

Adolescent↗
PubMed1985

Pulmonary involvement in mixed connective tissue disease.

To determine the frequency of pulmonary function abnormalities in mixed connective tissue disease (MCTD), we studied 16 consecutive patients. Spirometry, total lung capacity (TLC), diffusing capacity (Dco), static lung compliance (Cst), and tests of respiratory muscle function (peak inspiratory pressure [PIP] and the maximum change in transdiaphragmatic pressure [delta PDI] during a diaphragmatic Müeller maneuver) were obtained. Airway resistance (RAW) and frequency dependence of compliance were also measured. Static lung compliance was less than 0.2 L/cm H2O in four of nine patients. The PIP was less than 75 cm H2O in only one patient and delta PDI was greater than 45 cm H2O in all ten patients evaluated. Frequency dependence of compliance was abnormal in seven of ten patients, whereas RAW was increased in only three of eight patients. The TLC and DCO were less than 80 percent of the predicted values in ten of 16 and 14 of 16 patients respectively. There was no correlation between the level of extractable nuclear antigen and pulmonary function abnormalities. The study did not identify significant abnormalities in respiratory muscle function.

Adult↗
PubMed2006

Responses of the rat medullary neurons to central penicillin microinjection.

BACKGROUND: The microinjection of penicillin in the medulla oblongata caused different alterations in the global respiratory output. The purpose of this paper was to study the involvement of impulse activity and the functional relationship of bulbar neurons in mechanisms underlying experimentally induced respiratory arrhythmias. METHODS: Extracellular activity of neurons and diaphragmatic electromyogram activity were recorded and analyzed. RESULTS: Penicillin microinjection increased the mean discharge rate of bulbar neurons and caused the prolongation of discharge of inspiratory neurons. Cross-correlation analysis revealed new excitatory connections between neurons and a high level of positive synchronization of neuronal activity. CONCLUSION: The local blockage of synaptic inhibition by penicillin within respiratory areas leads to drastic changes in the functioning of neuronal elements of the single respiratory network.

Action Potentials↗
PubMedDate not supplied

Phrenic nerve conduction time measurement in pulmonary disorders.

Using surface electrodes over the lower chest wall, we have measured the phrenic nerve conduction time, i.e. the time interval between the stimulation of the phrenic nerve in the neck and the onset of the diaphragmatic muscle action potential, in 31 control subjects (bilaterally in 19 of them) and in patients in whom the phrenic nerve was at risk from intrathoracic disease. The data obtained from the patients showed that 1 degrees this technique, unlike fluoroscopic examination of the diaphragm, provides quantitative information on phrenic nerve function; in particular, it may detect partial impairment of the nerve by a neoplastic process; 2 degrees it allows an accurate assessment of phrenic nerve function even when lung collapse, pleural effusion, or pleural adhesions make it difficult to visualize the movement of the diaphragm; and 3 degrees it avoids the falsepositives seen on fluoroscopy. We suggest that measurement of phrenic nerve conduction time should be preferred to diaphragmatic fluoroscopic screening in the evaluation of phrenic nerve function (Acta neurol, belg, 1982, 82, 91-98).

Action Potentials↗
PubMed1980

The effect of training on strength and endurance of the diaphragm in quadriplegia.

The diaphragmatic electromyogram was used to detect fatigue of the diaphragm in six chronic quadriplegics while they breathed for 10 minutes against a variety of inspiratory resistances. The maximum static inspiratory mouth pressure was measured at functional residual capacity (Pmmax) and from the electromyogram the critical inspiratory mouth pressure that developed in each inspiration (Pmcrit) below which electromyographic changes of diaphragmatic fatigue do not develop was estimated. The measurements were repeated after 8, 12 and 16 weeks of inspiratory muscle training consisting of inspiring for a period of 30 minutes daily, six days a week, against a resistance just sufficient to produce the electromyographic changes of fatigue. A significant and progressive increase in Pmmax and Pmcrit was found during the training. It was concluded that (1) quadriplegics are predisposed to the development of inspiratory muscle fatigue due to reduced muscle strength and reduction in endurance, and (2) in these patients inspiratory muscle training increases both strength and endurance, and protects against fatigue.

Adolescent↗