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Results for “Diaphragmatic function”

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PubMed1989

[Long-term experiences with lyophilized soft dura (Lyodura S) as a connective tissue substitute in pediatric surgery].

Between 1979 and 1985 plastic closures with lyophilised softened dura mater were performed in 45 children with the following indications: gastrochisis: 8; omphaloceles: 2; meningomyeloceles: 29; meningoceles: 3; diaphragmatic aplasia: 1; oesophageal atresia with tracheo-oesophageal fistula: 2. Infection as well as rejection of the implants were never observed. Mortality came up to 11%. Complications and causes of death are described. A follow-up was carried out postoperatively at semi-annual intervals. The scars showed good functional and cosmetic results.

Abdominal Muscles↗

PubMed1982

The effect of aminophylline on inspiratory muscle contractility.

The effects of aminophylline on diaphragmatic muscle contractility were studied in 8 dogs. The relationships of the electromyographic signal from the diaphragm and the pressures developed by this muscle were compared before and after the administration of aminophylline in doses of 6, 20, 40, 80, and 120 mg/kg. Measurements were made during occluded inspiratory efforts at functional residual capacity. In a second group of 4 dogs the relationships were compared while the rib cage expansion was limited by a plaster cast. Finally, in a third group of 4 dogs after the diaphragm had been paralyzed by phrenicotomy, the relationship of pleural pressure to the electromyographic signal of the intercostal muscles was assessed before and after administration of aminophylline. In all cases, aminophylline progressively shifted the electromyographic pressure relationship up and to the left. This effect became significant (p less than 0.01) at a dose of 20 mg/kg, reached a peak at 80 mg/kg, and then declined at a dose of 120 mg/kg. The amount producing blood concentrations closest to the human therapeutic blood concentration was 20 mg/kg. The peak increase in pressure compared with the control values were 58% in the first group, 27% in the second group, and 52% in the third group (p less than 0.01). We conclude that aminophylline increases respiratory muscle contractility in a dose-related manner. This may have important therapeutic and pathophysiologic implications.

Aminophylline↗

PubMed1989

Ventilation and breathing pattern during sleep in Duchenne muscular dystrophy.

Ventilatory data, including timing and partitioning of ventilation, were obtained from six subjects with advanced Duchenne muscular dystrophy, aged 16 to 22 years, during polysomnography on two consecutive nights; the subjects were randomized to breathing air or oxygen. Five of the six patients developed oxygen desaturation exceeding 5 percent during rapid eye movement (REM) sleep while breathing air. Minute ventilation on air (the mean of at least six consecutive minutes) was 6.9 +/- 0.7 (SEM) L min-1 but fell, owing to decreases in both tidal volume and frequency, to 4.9 +/- 0.3 L min-1 (p less than 0.05) in slow wave sleep and to 4.5 +/- 0.6 L min-1 (p less than 0.05) in REM sleep. Similar falls were seen on oxygen. The variability of all ventilatory data was significantly greater in REM than non-REM (NREM) sleep. The mean abdominal contribution to breathing was lower than predicted for wakefulness and all sleep stages, and two subjects showed paradoxical abdominal movement in NREM sleep; a correlation (p less than 0.05) existed between the NREM abdominal (diaphragmatic) contribution and the extent of oxygen desaturation subsequently seen in REM. We conclude that although awake minute ventilation is normal in Duchenne muscular dystrophy, hypoventilation occurs in all sleep stages, and those with diaphragmatic dysfunction are especially vulnerable to oxygen desaturation during REM sleep.

Adolescent↗

PubMed1989

[State of the valvular function of the cardia in patients with duodenal ulcer before and after vagotomy and methods of its correction].

The authors studied the valvular function of the cardia in 714 patients who were kept under regular medical observation and in 138 patients who had been operated on for duodenal ulcer. Changes were found in the cardia of 9.4% of patients who underwent regular medical examination and in 17% of these subjected to operation. The valvular function of the cardia was impaired after vagotomy in all cases. Fundoesophagocrurorhaphy is the best method for correction of cardiac dysfunction.

Cardia↗

PubMed1989

[The surgical anatomy of the genital nerves of the male and their preservation in excision of the rectum].

Studies of the fetus and new-born were undertaken to determine the exact localization of the nn. erigentes in the lower pelvis. The particular topography was visualized using histological slides and a special digital imaging technique. The nn. erigentes were found to be bundled along the diaphragmatic part of the urethra before entering the two cavernous bodies of the penis. These findings suggest that a small anterior patch of rectal muscle covering the diaphragmatic part of the urethra should be left behind in male patients undergoing total proctocolectomy in order to preserve potency. This operative technique cannot be employed for carcinomas extending to the anterior rectal wall. Since 1980, the new technique has been used in 18 male patients with rectal carcinoma and sexual function was preserved in all cases.

Adult↗

PubMed2006

Supramaximal inflation improves lung compliance in subjects with amyotrophic lateral sclerosis.

RATIONALE: Lung compliance has been found to be low in patients with chronic diaphragmatic weakness or paralysis but has not been well-studied in patients with amyotrophic lateral sclerosis (ALS). Noninvasive positive-pressure ventilation (NPPV) prolongs survival in ALS patients but may also have additional beneficial effects. OBJECTIVES: This study evaluated static expiratory lung compliance (CL) in subjects with ALS and determined the effect of lung inflation with supramaximal inflation on CL. DESIGN: This was a prospective trial comparing CL before and after supramaximal lung inflation via mouthpiece-delivered positive pressure. SETTING: A single university medical center with an multidisciplinary ALS center. PARTICIPANTS: Fourteen subjects with ALS were compared to 4 healthy volunteers. INTERVENTIONS: Subjects underwent a battery of pulmonary function tests including for CL. Then they used positive pressure administered via a mouthpiece set to 10 cm H2O above their maximal static recoil pressure for 5 min. The CL measurement was then repeated. RESULTS: The mean (+/- SD) baseline CL was reduced (164.1 +/- 82.1 mL/cm H2O) in subjects with ALS and was significantly lower than that in healthy volunteers (237.5 mL/cm H2O; p = 0.04). CL increased significantly in subjects with evidence of diaphragm weakness (change in CL, 11.3 +/- 16.7 mL/cm H2O; p = 0.03). Healthy volunteers did not have an increase in CL. CONCLUSIONS: Patients with ALS and diaphragmatic weakness have reduced CL, and brief supramaximal inflation increases CL. These findings suggest that atelectasis or increased alveolar surface forces are present in ALS patients and that these patients will have increased work of breathing. Some of the beneficial effects demonstrated with NPPV therapy may be through its effects on CL and the work of breathing.

Adult↗

PubMed1994

Buthionine sulfoximine treatment impairs rat diaphragm function.

Activation of the glutathione (GSH) redox cycle with production of glutathione disulfide (GSSG) has been shown to occur in the diaphragm during inspiratory resistive loading (RB). Buthionine sulfoximine (BSO) lowers tissue GSH by irreversibly inhibiting the rate-limiting synthesis enzyme gamma-glutamylcysteine synthetase. We investigated the effects of BSO on rat diaphragm function, both at rest and after a period of RB. Rats in the RB groups underwent inspiratory RB until they were unable to sustain 70% of their maximal airway pressure. A portion of the diaphragm was analyzed for GSH and GSSG levels, and measurements of in vitro contractile properties included contraction times, maximal tetanic tension (Po), maximal twitch tension (Pt), and force frequency curves. BSO treatment produced a profound depletion of diaphragmatic GSH. Neither BSO nor RB alone significantly altered diaphragm contractile properties at this load of RB. But, in BSO-RB rats, there was a significant decrease in Pt, Po, and tetanic tension at all frequencies of stimulation compared with those in other groups. These data reveal that animals treated with BSO followed by inspiratory resistive loading exhibit marked diaphragm impairment, suggesting that GSH may play an important role in protecting the diaphragm from the stress induced by this resistive breathing protocol.

Analysis of Variance↗

PubMed1996

[Augmented spontaneous breathing].

Impaired pulmonary gas exchange can result from lung parenchymal failure inducing oxygenation deficiency and fatigue of the respiratory muscles, which is characterized by hypercapnia or a combination of both mechanisms. Contractility of and coordination between the diaphragm and the thoracoabdominal respiratory muscles predominantly determine the efficiency of spontaneous breathing. Sepsis, cardiac failure, malnutrition or acute changes of the load conditions may induce fatigue of the respiratory muscles. Augmentation of spontaneous breathing is not only achieved by the application of different technical principles or devices; it also has to improve perfusion, metabolism, load conditions and contractility of the respiratory muscles. Intermittent mandatory ventilation (IMV) allows spontaneous breathing of the patient and augments alveolar ventilation by periodically applying positive airway pressure tidal volumes, which are generated by the respirator. Potential advantages include lower mean airway pressure (PAW), as compared with controlled mechanical ventilation, and improved haemodynamics. Suboptimal IMV systems may impose increased work and oxygen cost of breathing, fatigue of the respiratory muscles and CO2 retention. During pressure support ventilation (PSV), inspiratory alterations of PAW or gas flow (trigger) are detected by the respirator, which delivers a gas flow to maintain PAW at a fixed value (usually 5-20 cm H2O) during inspiration. PSV may be combined with other modalities of respiratory therapy such as IMV or CPAP. Claimed advantages of PSV include decreased effort of breathing, reduced systemic and respiratory muscle consumption of oxygen, prophylaxis of diaphragmatic fatigue and an improved extubation rate after prolonged periods of mechanical ventilation. Minimum alveolar ventilation is not guaranteed during PSV; thus, close observation of the patient is mandatory to avoid serious respiratory complications. Continuous positive airway pressure breathing (CPAP) maintains PAW above atmospheric pressure throughout the respiratory cycle, which may increase functional residual capacity and decrease the effort of breathing. CPAP has been conceptually designed for the augmentation of spontaneous breathing and requires the intact central and peripheral regulation of the respiratory system. Airway pressure release ventilation (APRV) improves alveolar ventilation by intermittent release of PAW, which is kept above atmospheric pressure by means of a high-flow CPAP system. The opening of an expiratory valve for 1-2 s induces a decreased PAW and lung volume, which increases rapidly to pre-exhalation values after closure of the valve due to the high gas flow within the circuit (90-100 1/min). APRV may improve haemodynamics and VA/Q distribution as compared with conventional mechanical ventilation. Biphasic positive airway pressure (BIPAP) is characterized by the combination of spontaneous breathing and time-regulated, pressure-controlled mechanical ventilation. During the respiratory cycle the ventilator generates two alternating CPAP levels, which can be modified with regard to time and pressure. As with APRV, alveolar ventilation is maintained even if the spontaneous breathing efforts of the patient cease, which improves the safety of both modes of respiratory therapy. The contribution of spontaneous breathing to total minute ventilation may be important, since a decreased shunt and improved VA/Q relationship have been observed in experimental non-cardiogenic lung oedema. These data give support to the concept that spontaneous breathing should be maintained and augmented in the setting of acute respiratory failure.

Humans↗

PubMed1986

Contamination of lung lymph following standard and modified procedures in sheep.

The sheep lung lymph fistula preparation of Staub et al. is reported to be contaminated by systemic lymph. The published estimates of contamination range from 5% (awake sheep) to 60% (anesthetized sheep). In view of these conflicting estimates, we investigated the pre- and postoperative contaminating sources, morphological and functional consequences of the proposed contamination reducing modifications, and base-line lung lymph flow in awake sheep following standard and modified cannulation procedures. Our morphological observations are not compatible with the higher estimates of contamination (25-60%). Evidence of lymph leakage from cauterized lymphatics was found. The lymphatics that appear after diaphragmatic cautery and partial resection of caudal mediastinal lymph node were found to constitute "new" contaminating sources. The lymph flow data from base-line and increased vascular pressure conditions were consistent with the reported low estimates of contamination (5%). We propose simple modifications of the standard procedure of Staub et al. which may be nearly as effective in reducing contamination by extrapulmonary lymph as the more invasive and/or traumatic modifications.

Animals↗

PubMed1998

Outpatient management.

The successful management of outpatients with COPD requires a multifaceted approach that includes prophylactic, palliative, and life-extending therapies. All patients should undergo smoking cessation, avoid potentially harmful environments, and receive influenza and pneumococcal vaccines at recommended intervals. Although medical therapy may yield only marginal benefits in patients with minimal airway responsiveness, even small improvements may translate into significant functional benefits and will be greatly appreciated. Therefore, every effort should be expended to optimize the patient's medical regimen and to ascertain that methods of delivery (such as use of spacers) are as recommended. Physical therapy measures may be useful in patients with copious sputum production, and pursed-lip and diaphragmatic breathing exercises may reduce dyspnea and lend a sense of control to patients with severe flow limitation. Oxygen therapy is the only modality demonstrated to improve survival in patients with severe COPD and may give symptomatic relief to some patients. Its use, however, is restricted to patients meeting guidelines for hypoxemia, and although dyspneic patients not meeting these guidelines may desire oxygen, insurers will decline coverage for them. Newer modalities, such as noninvasive ventilation, may improve gas exchange and quality of life in some patients with hypercapnia and nocturnal oxygen desaturations, but subgroups of COPD patients who benefit have not been well-defined, and pending further investigation, guidelines for use should be considered tentative. Patients should be encouraged to enter a comprehensive rehabilitation program, but if one is unavailable or the patient declines, a rehabilitation approach should be applied. Practitioners should attempt to educate patients at each visit, offering advice not only on medications, but also on regular exercise, good nutrition, and ways of coping psychologically with chronic illness. By taking such a comprehensive and caring approach, and being available to assist with problems and crises, the practitioner can help to enhance the quality and length of the COPD patient's life.

Acute Disease↗

PubMed2000

The appropriate setting of noninvasive pressure support ventilation in stable COPD patients.

STUDY OBJECTIVE: To evaluate the short-term physiologic effects of two settings of nasal pressure-support ventilation (NPSV) in stable COPD patients with chronic hypercapnia. DESIGN: Randomized controlled physiologic study. SETTING: Lung function units and outpatient clinic of two affiliated pulmonary rehabilitation centers. PATIENTS: Twenty-three patients receiving domiciliary nocturnal NPSV for a mean (+/- SD) duration of 31 +/- 20 months. METHODS: Evaluation of arterial blood gases, breathing pattern, respiratory muscles, and dynamic intrinsic positive end-expiratory pressure (PEEPi,dyn) during both unassisted and assisted ventilation. Two settings of NPSV were randomly applied for 30 min each: (1) usual setting (U), the setting of NPSV actually used by the individual patient at home; and (2) physiologic setting (PHY), the level of inspiratory pressure support (IPS) and external positive end-expiratory pressure (PEEPe) tailored to patient according to invasive evaluation of respiratory muscular function and mechanics. RESULTS: All patients tolerated NPSV well throughout the procedure. Mean U was IPS, 16 +/- 3 cm H(2)O and PEEPe, 3.6 +/- 1.4 cm H(2)O; mean PHY was IPS, 15 +/- 3 cm H(2)O and PEEPe, 3.1 +/- 1.6 cm H(2)O. NPSV was able to significantly (p < 0.01) improve arterial blood gases independent of the setting applied. When compared with spontaneous breathing, both settings induced a significant increase in minute ventilation (p < 0.01). Both settings were able to reduce the diaphragmatic pressure-time product, but the reduction was significantly greater with PHY (by 64%; p < 0.01) than with U (56%; p < 0.05). Eleven of 23 patients (48%) with U and 7 of 23 patients (30%) with PHY showed ineffective efforts (IE); the prevalence of IE (20 +/- 39% vs 6 +/- 11% of their respiratory rate with U and PHY, respectively) was statistically different (p < 0.05). CONCLUSION: In COPD patients with chronic hypercapnia, NPSV is effective in improving arterial blood gases and in unloading inspiratory muscles independent of whether it is set on the basis of patient comfort and improvement in arterial blood gases or tailored to a patient's respiratory muscle effort and mechanics. However, setting of inspiratory assistance and PEEPe by the invasive evaluation of lung mechanics and respiratory muscle function may result in reduction in ineffective inspiratory efforts. These short-term results must be confirmed in the long-term clinical setting.

Aged↗

PubMed1981

Importance of inspiratory muscle tone in maintenance of FRC in the newborn.

The importance of inspiratory muscle tone in the maintenance of functional residual capacity (FRC) in newborns was studied in eight premature infants with birth weights of 1,166 +/- 217 g and gestational age 29 +/- 1.9 wk (mean +/- SD). Rib cage and abdominal anteroposterior diameters were monitored with magnetometers, and electromyograms of the diaphragm and intercostal muscles were recorded with surface electrodes. Sleep state was monitored using electrooculogram and behavioral criteria. We assessed the decrease in tonic activity of the inspiratory muscles and the fall in end-expiratory lung volume during apnea compared with the period just preceding apnea. A total of 98 apneas were analyzed. In all instances a decrease in diaphragmatic and intercostal tone was associated with a decrease in the anteroposterior diameter of both rib cage and abdomen, indicating a fall in FRC. These changes were more marked during quiet sleep than during rapid-eye-movement sleep (P less than 0.01). Our results suggest that inspiratory muscle tone is a major determinant of FRC in the newborn.

Apnea↗

PubMed1987

[Complex roentgenoendoscopic examinations in the diagnosis of hiatal hernia and functional insufficiency of the cardia].

The authors make an analysis of findings of endoscopic and rentgenological methods of examination of patients with incompetent closing apparatus of the cardioesophageal zone which increased the informative value and rentgen-endoscopic criteria of diagnostics of hiatal hernias and functional incompetence of the cardia, helped to find out their correlation with disturbed functions of the esophagus, stomach and duodenum. The correct diagnosis in its turn facilitates choice of the adequate method of treatment.

Cardia↗

PubMed1975

[Results of surgical treatment of benign non-epithelial tumors and cysts of the esophagus].

Based on questionnaires, roentgenological and esophagotonokimographic studies the authors present an analysis of the results of surgical therapy in 33 patients showing benign non-epithelial neoplasms of the esophagus. Comparative data on the frequency and character of pathological signs appearing prior to and after surgery are reported. The necessity of a differential approach to formulating indications to surgical treatment of benign esophageal tumors and cysts is emphasized, since serious functional disorders arising postoperatively should be warranted by the rationality of a surgical intervention.

Cysts↗

PubMed1997

Contributions by individual lungs to the surfactant status in congenital diaphragmatic hernia.

Laboratory evidence has recently confirmed clinical reports suggesting that the surfactant system is abnormal in congenital diaphragmatic hernia (CDH). Autopsy series show that, although both lungs are affected by the maldevelopment, the ipsilateral lung is more severely affected. The aim of this study was to examine the surfactant status in each lung in a lamb model of CDH. The lamb CDH model was created on the left side at 80 d of gestation and delivered near term. Subsequently, the lungs were removed and separated from each other. Bronchoalveolar lavage and type II pneumocyte isolations were performed on each side separately. Lavage analyses showed decreased phospholipid (0.12 versus 0.42 mg/g), per cent phosphatidylcholine (51% versus 79%) surfactant-associated protein A (0.20 versus 2.68 mg/g), and surfactant-associated protein-B (0.35 versus 2.21 mg/g) in CDH lungs compared with control lungs. However, no differences were seen between the ipsilateral and contralateral lungs of either CDH or control groups. This was in contrast to the phosphatidylcholine biosynthetic abilities of type II cells isolated from CDH lungs, which were not only lower than those from control lungs (0.15 versus 0.40 nmol/10(6) cells/h), but were also significantly worse in the ipsilateral CDH lung compared with the contralateral CDH lung (0.10 versus 0.20 nmol/10(6) cells/h). Further studies utilizing radiolabeled exogenous surfactant injected in the lower contralateral lung indicate that discrepancies between the presence of type II cell function differences between lungs, and the lack of biochemical differences between the two lungs in CDH, may be due to in utero mixing of lung fluid.

Animals↗

PubMed1994

Plication of paralyzed hemidiaphragm after right sleeve pneumonectomy.

Right diaphragmatic plication was performed in a 62-year-old man who underwent right sleeve pneumonectomy and then required prolonged mechanical ventilation owing to right diaphragmatic paralysis. The plication was very effective in allowing him to be weaned from the ventilator. The transdiaphragmatic pressure, the ratio of gastric to esophageal pressure swing, and the work of breathing per liter of ventilation improved remarkably after plication. Our experience indicates the beneficial effect of such a plication on contralateral lung function from the standpoint of clinical and respiratory mechanics.

Carcinoma, Squamous Cell↗

PubMedDate not supplied

[Asbestos-related pleural plaques: a literature review].

Pleural plaques (PP) are considered to be hallmarks of asbestos exposure. They constitute focal thickenings of the pleura and are commonly seen in patients without lung disease. They can involve parietal, diaphragmatic and mediastinal pleura. Chest x-ray is frequently used for PP diagnosis, but computed tomography, especially when used the high-resolution technique, is the imaging exam with the greatest sensibility and specificity. PP are almost always asymptomatic, but there are some controversial about their relationship with asbestos exposure indexes, pulmonary functional alterations and risk of neoplasias.

Asbestos↗

PubMed1989

Reversible respiratory muscle weakness in hyperthyroidism.

Breathlessness is a common complaint in patients with hyperthyroidism, and respiratory failure requiring artificial ventilation, although rare, can occur. While a proximal myopathy is frequently recognized, diaphragm muscle function has not hitherto been studied in detail in thyrotoxicosis. The strength of the quadriceps femoris and respiratory muscles was therefore assessed in seven consecutive thyrotoxic patients, on presentation and during medical treatment, when euthyroid. Prior to therapy, reduced quadriceps muscle strength, vital capacity, and global expiratory and inspiratory muscle strength were found. Diaphragmatic weakness was present in one of four patients studied by measuring transdiaphragmatic pressures during maximal sniffs and during bilateral phrenic nerve stimulation at 1 Hz (twitch). After treatment, significant improvement occurred in quadriceps muscle strength, vital capacity, and global respiratory muscle strength. Sniff and twitch transdiaphragmatic pressures also increased significantly. These results indicate that respiratory muscle weakness occurs in hyperthyroidism and that such weakness is reversible with medical treatment. It is important to realize that respiratory muscles may be directly affected when assessing thyrotoxic patients with breathlessness, as severe involvement of the respiratory muscles may cause respiratory failure.

Chronic Disease↗