SEARCH · PubMed Health

Results for “Diaphragmatic function”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 1,243 records · Page 69Linked to original sources

PubMed1984

[The striated sphincter of the urethra. 2: Specific methods for studying the striated sphincter of the urethra].

Radiology and electromyography of the lower urinary tract are specific techniques for exploration of the urethral rhabdosphincter. Retrograde and mictional urethrography provide data on the extent of the membranous urethra. In the presence of rhabdosphincter lesions a mictional urethrogram is often sufficient to establish a diagnosis from the direct and indirect signs of obstruction it supplies. A retrograde urethrography examination can be added validly to the previous exploration to improve precise definition of sclerosis: in contrast it is indispensable when miction is impossible. Differential diagnosis between spasm and stenosis of striated and dyssynergy of smooth muscle sphincter is by pharmacologic tests. Radiologic study of sphincter contraction is generally by cineradiography with arrest of miction. Results are limited, however, when compared with those of a radiodynamic study: the latter supplies information on the functioning of the para- and peri-urethral rhabdosphincter, and allows measurement of contraction. The electromyogram, with its different practical technical modalities, provides details of the urethral rhabdosphincter. The contact electromyogram gives quantitative data but fails to diagnose a neurological lesion. It analyzes behavior of the sphincter in its para-urethral part and can localize its diaphragmatic portion; dynamic electric profiles are of little reliability, in contrast to static profiles which quantify electric activity at all points in the urethra during the same contraction. The standard percutaneous needle electromyography examination provides qualitative data on the peri-urethral rhabdosphincter, but lacks precision as to the region explored, while qualitative information on the para-urethral sphincter requires the use of an endo-urethral approach. A difference in potential between para- and peri-urethral musculature has been demonstrated a fact confirmed by anatomical findings in Goslings study. In normal subjects, the rhabdosphincter differs from other skeletal muscles by its constant activity except during miction; potentials in children differ from those in adults by their duration. In lower motor neurone disease signs of denervation appear after several weeks, while in upper motor neurone affections the potentials are normal but nociceptive and bulbocavernous stimuli provoke bursts of hyperactivity which reappear very shortly after the paraplegia. Striated muscle fibrosis provokes peripheral signs with persistence of regions of increased reflexes. Tests of responses to stimuli provide important information enabling the site of the neurogenic lesion to be determined.

Electromyography↗

PubMed1982

[Notes on the use of the Angelchik-Cohen ring].

Results obtained by using Angelchik and Cohen's ring prosthesis in 10 patients with hernia due to sliding through the oesophageal hiatus of the diaphragm are reported. In 8 patients, the ring was perfectly tolerated and performed its antireflux and hernia containment functions. In the 2 other patients, however, the prosthesis rose to the mediastinum, causing hernia to recur in one case and leading to recurrence of symptomatology in the other.

Adult↗

PubMed1996

Difference between functional residual capacity and elastic equilibrium volume in patients with chronic obstructive pulmonary disease.

BACKGROUND: A study was performed to determine the elastic equilibrium volume (Vr) of the respiratory system in patients with chronic obstructive pulmonary disease (COPD). METHODS: Voluntary relaxed expiration from total lung capacity (TLC) was studied in three groups of subjects: seven patients with severe chronic airways obstruction (COPD), 10 normal subjects, and 15 subjects with restrictive disease. RESULTS: In the normal subjects and the patients with restrictive disease voluntary relaxed expiration from TLC stopped close to end tidal volume (FRC) and the volume expired in this manoeuvre was less than that expired in a slow vital capacity manoeuvre (SVC). In the patients with COPD the voluntary relaxed expiration continued beyond the end tidal volume (FRC) and the volume expired was not different from the SVC. Oesophageal (pleural) pressures and surface diaphragmatic EMG recordings in the patients with COPD supported the premise that relaxation was achieved. CONCLUSIONS: In patients with COPD, end tidal volume (FRC) is higher than the elastic equilibrium volume, Vr, of the respiratory system. This is in contrast to patients with restrictive disease and normal subjects in whom end tidal volume (FRC) is close to Vr. This study shows that, in patients with severe chronic obstructive pulmonary disease, Vr is at least as small as residual volume (RV).

Functional Residual Capacity↗

PubMed1989

Perioperative cardiac pacing using an atrioventricular pacing pulmonary artery catheter.

An atrioventricular pacing thermodilution pulmonary artery catheter was evaluated in 40 patients undergoing cardiac surgery. The catheter was inserted in all study patients in a timely fashion without difficulty and functioned well during the perioperative period. Before the start of cardiopulmonary bypass, atrial capture was achieved in 98% of the patients (threshold mean 4.9 mA), ventricular capture in 100% (threshold mean 3.0 mA) and atrioventricular sequential (AVS) pacing in 98%. After cardiopulmonary bypass, atrial capture was achieved in 95% of the patients (threshold mean 5.2 mA), ventricular pacing in 100% (threshold mean 3.1 mA), and sequential pacing in 95%. In 27 patients in whom cardiac outputs were recorded, cardiac index increased an average of 45% (range 8% to 95%) with atrial or AVS pacing over ventricular pacing alone. In 11 patients, extended atrial pacing was used postoperatively, the longest for 93 hours. No major complications could be attributed to the study catheter. Minor complications included diaphragmatic stimulation in one patient and supraventricular tachycardia, possibly related to atrial pacing postoperatively, in one patient. These data suggest that this catheter/pacing system is effective and reliable for hemodynamic monitoring and temporary atrial or AVS pacing. In addition, the atrial pacing probe can be used perioperatively to record atrial electrograms to facilitate the diagnosis of supraventricular tachyarrhythmias.

Aged↗

PubMed1982

Action of costal and crural parts of the diaphragm on the rib cage in dog.

We studied the action of the costal and crural (vertebral) parts of the diaphragm on the lower rib cage in normal supine dogs. The two parts of the diaphragm were separately stimulated by electrodes directly implanted in the muscle or via the different phrenic nerve roots in the neck. The results of the experiments indicate the following. 1) The costal and crural parts of the diaphragm have a different segmental innervation and a different mechanical action on the rib cage. 2) The costal diaphragm expands the lower rib cage when it contracts. This rib-cage expansion is due mostly to the fulcrum of the abdominal contents and partly to the rise in abdominal pressure that takes place during diaphragmatic contraction. The pericardial attachments play no role in this action of the diaphragm. 3) The action of the crural diaphragm on the lower rib cage depends only on the balance between the inspiratory force exerted by the rise in abdominal pressure and the expiratory force exerted by the fall in pleural pressure. In the intact animal at functional residual capacity, these two opposite effects cancel each other. 4) The inflationary action of both parts on the rib cage decreases progressively as lung volume increases. The findings also suggest that the rise in abdominal pressure which occurs when the diaphragm contracts expands the lower rib cage by acting through the area of apposition of the diaphragm to the rib cage. These findings also strengthen the idea that the diaphragm actually consists of two muscles.

Abdomen↗

PubMed2002

Airway clearance strategies for the pediatric patient.

Clinicians who care for cystic fibrosis (CF) patients have many techniques to choose from to facilitate mucus clearance. Little has been published about when to introduce the various techniques and in what order to teach them. Debates have occurred over these issues in the CF community, and there is now consensus on some topics. It is very important to teach adherence to therapy at an early age. Adherence to an airway clearing regimen assists in maintaining good pulmonary function in CF patients. Knowing when and how to introduce airway clearance techniques beyond chest physiotherapy (CPT) is clinically relevant and useful. A 5-position modified CPT routine can be used with infants and children, and it takes less time and may improve adherence. Infants and toddlers can be taught breathing games that eventually lead them to perform diaphragmatic breathing and huffing. Once they have mastered diaphragmatic breathing and huffing, children can be taught the active cycle of breathing technique. Modified CPT can be phased out at that point. Positive expiratory pressure therapy can usually be introduced around 6-7 years of age. High-frequency chest wall oscillation, oscillating positive expiratory pressure, and autogenic drainage all follow. CF patients should be given every opportunity to learn and master various techniques to promote mucus clearance.

Breathing Exercises↗

PubMed1997

Bronchiolitis obliterans organizing pneumonia as an initial manifestation in patients with systemic lupus erythematosus.

Diverse pleuropulmonary manifestations including diaphragmatic dysfunction, pleural effusion, acute lupus pneumonitis, pulmonary hemorrhage, pulmonary hypertension, and diffuse interstitial lung disease have been described in patients with systemic lupus erythematosus (SLE). Bronchiolitis obliterans organizing pneumonia (BOOP) as an initial manifestation of SLE is rarely reported. We describe 2 patients who had SLE concurrent with the onset of BOOP. Their respiratory symptoms, followup pulmonary function tests, and radiologic findings showed much improvement after steroid therapy.

Adult↗

PubMed2006

Thoracoscopic diaphragmatic repair for refractory hepatic hydrothorax: application of pleural flap and mesh onlay reinforcement.

BACKGROUND: Management of hepatic hydrothorax is difficult, and no radical treatment has been established. Based on accumulating evidence that diaphragmatic defects contribute to hepatic hydrothorax, we developed a diaphragmatic repair method for the management of this complex condition. METHODS: From October 2003 to March 2005, 10 patients (age, 32 - 83 years; 6 men and 4 women) with refractory hepatic hydrothorax (Child-Pugh class B-C) underwent thoracoscopic pleura (n = 7) or mesh (n = 3) onlay reinforcement to repair the diaphragmatic defects on which this study focuses, and all patients have since been under follow-up in a prospective observation study. RESULTS: After a mean of 7.7 months of follow-up examinations, no local recurrence occurred in all patients. Two patients died of hemorrhage from esophageal varices two months postoperatively. All patients had a better postoperative pulmonary function. CONCLUSION: The use of pleura and mesh onlay reinforcement of the diaphragm is an encouraging treatment for refractory hepatic hydrothorax.

Adult↗

PubMed1985

[Function of the respiratory muscles in acute cardiac decompensation].

In anesthetized dogs the performance of the respiratory muscles during cardiogenic shock and their influence on its outcome was studied. Shock was induced by cardiac tamponade. Cardiac output during shock amounted to 25-35% of control and was kept constant. Minute ventilation (VE) initially increased and then progressively decreased until respiratory arrest. The latter was due to impairment of respiratory muscle contractility, the pressure generated by the diaphragm (Pdi) decreasing despite a marked increase in the diaphragmatic electromyogram and of the phrenogram. Mechanical ventilation during shock prolonged survival for the same decrease in cardiac output, and also decreased substantially the severity of lactic acidosis. Furthermore, blood flow to the respiratory muscles during shock was different in the animals breathing spontaneously (SB) from that in mechanically ventilated animals (MV). The fraction of cardiac output distributed to the respiratory muscles during control amounted to 1.85% in MV and 2.79% in SB. With shock this decreased to 1.55% in MV while in SB it decreased by 21%, which suggests that mechanical ventilation during shock preserves a large portion of cardiac output used by the respiratory muscles during spontaneous breathing, thus making it available to other organs.

Animals↗

PubMed1998

Lung growth and maturation after tracheal occlusion in diaphragmatic hernia.

Tracheal occlusion (TO) was performed at 120 d of gestation by noninvasive endoscopic technique using a releasable latex balloon, in fetal lambs with diaphragmatic hernia (DH) established at 85 d. The lungs were studied at 139 d in five fetuses with DH + TO, five fetuses with DH only, and six control fetuses. Fluid retention consecutive to TO allowed fetal lungs to grow. Histological pulmonary structure was more mature in DH + TO than in DH alone. The growth-inducing effect of TO was however incomplete, with an increased protein/DNA ratio. Tissue phospholipids were increased, but this was not reflected in the surfactant compartment. The major surfactant component, disaturated phosphatidylcholine, was reduced to 58% of its control value in DH, and further reduced to 17.5% of its control value in DH + TO. The proportion of surfactant protein B immunoreactive cells, assumed to represent the proportion of type II cells, was increased in DH (27% of all parenchymal cells), and reduced in DH + TO (7.8%) as compared with control fetuses (15%). In conclusion, although noninvasive tracheal occlusion in utero is feasible and may partly compensate the adverse effects of DH on lung organogenesis, it reduces the number of type II cells and induces a dramatic surfactant deficit. Using this technique in human fetuses requires careful consideration until further evaluation of lung functional characteristics has been achieved in this experimental model.

Animals↗

PubMed2006

The tendency to altered perception of airflow resistance in aged subjects might be due mainly to a reduction in diaphragmatic proprioception.

Elderly patients with asthma, particularly those above the age of 80 years, appear less able to detect early worsening of their airflow resistance and hence might not take 'rescue' bronchodilator medication promptly. No consistent explanation for the observation has been posited. We hypothesize that deterioration in the sensitivity and accuracy of inspiratory (mainly diaphragmatic) proprioception is a plausible mechanism. This contention is supported by observations that indicate the central role of afferent phrenic nerve fibres arising from mechanoreceptors in diaphragmatic muscle and entheses in the ability to sense changes in intrathoracic pressure and volume. Other sensory afferent sources appear less important in this context because the ability to detect intrathoracic pressure and volume changes is preserved in patients with heart-lung transplants (parenchymal and airway denervation), topically anaesthetized upper airways and spinal cord transection below C4 (intact phrenic function) but not cord transection above C2 (phrenic function absent) if the airways are simultaneously anaesthetized. Further support for the hypothesis comes from demonstration of reduced integrated proprioceptive function in older subjects, such as increased postural sway, reduced ability to judge changes in joint position and slower recovery from eye and hand perturbation. In the context of asthma, the detection of a change in airflow resistance depends mainly on the subconscious detection of a mismatch between the inspiratory effort and the volume change achieved; the resulting discrepancy between length (volume) and tension (muscular effort) is felt as a sensation of obstructed breathing, resulting in greater effort to breath and conscious actions such as self-medication. Our hypothesis proposes that a reduced ability to detect accurately the volume change during tidal breathing delays the sensing of the obstruction in older subjects.

Aged↗

PubMed2005

Effects of different ventilator settings on sleep and inspiratory effort in patients with neuromuscular disease.

Patients with neuromuscular disease (NMD) who require long-term ventilation normally have the ventilation set using empirical daytime parameters. We evaluated arterial blood gases (ABG), breathing pattern, respiratory muscle function, and sleep architecture during ventilation with two noninvasive Pressure Support Ventilation (nPSV) settings in nine patients with NMD. The two settings were randomly applied: the usual (US), with the nPSV setting titrated on simple clinical parameters, and the physiological (PHYS), tailored to the patient's respiratory effort. During wakefulness, nPSV significantly improved ABG and minute ventilation and reduced the diaphragmatic pressure-time product (PTPdi/breath), independently of the type of setting (PTPdi/breath spontaneous breathing 5.7 +/- 2.4, US 3.2 +/- 2, PHYS 3.6 +/- 1.6 cm H2O . seconds(-1), p < 0.001). However, during sleep, PHY nPSV resulted in a significant improvement of gas exchange, sleep efficiency (71.7% +/- 14 US vs. 80.6% +/- 8.3 PHYS, p < 0.01) and % of REM sleep (9.1% +/- 7 US vs. 17.3% +/- 5.4 PHYS, p < 0.01). This improvement was significantly correlated with the reduction in ineffective efforts. In NMD, nPSV is effective in improving daytime ABG and in unloading inspiratory muscles independently of whether it is set on the basis of the patient's comfort or the patient's respiratory mechanics. However, PHYS was associated with better sleep architecture and nighttime gas exchange.

Adult↗

PubMed1982

Diaphragmatic breathing training and walking performance in chronic airways obstruction.

Eight patients with chronic obstructive bronchitis and moderate disability entered a pilot study of the effects of controlled diaphragmatic breathing. They received three weeks of placebo physiotherapy (shoulder exercises) followed by three weeks of instruction on controlled diaphragmatic breathing. No beneficial effects were observed on exercise performance or the perceived strain of exercise.

Aged↗

PubMed1994

Pathophysiology of congenital diaphragmatic hernia. V. Effect of exogenous surfactant therapy on gas exchange and lung mechanics in the lamb congenital diaphragmatic hernia model.

The aim of this study was to assess the impact of surfactant deficiency on the pathophysiology of congenital diaphragmatic hernia (CDH). Pregnant ewes were operated on at 80 days of gestation for creation of a diaphragmatic hernia in the lambs. Twenty-one lambs survived to be delivered by cesarean section and were studied. Compliance was improved when surface tension effects were removed by saline solution in lungs of both control animals and lambs with CDH; however, the lungs of the lambs with CDH still had significantly impaired compliance. In a second series of experiments, two groups were studied: a surfactant-treated and a control, nontreated group. Surfactant was given prophylactically into the liquid-filled lungs before the first breath. All lambs were paralyzed and sedated and their lungs mechanically ventilated with 100% oxygen for 30 minutes; gas exchange was then assessed, pressure-volume data were obtained, and compliance was calculated. Surfactant significantly improved gas exchange; arterial oxygen pressure increased from 39 +/- 11.4 to 316 +/- 53.6 mm Hg, arterial carbon dioxide pressure decreased from 148 to 63 mm Hg, and pH increased from 6.87 to 7.16 (p < 0.001). Lung volume at 25 cm H2O, functional residual capacity, and compliance were all increased (p < 0.02). Thus, in the CDH lamb model, pulmonary mechanics are impaired by both parenchymal and surfactant abnormalities. Both lung mechanics and gas exchange are markedly improved by exogenous surfactant therapy.

Animals↗

PubMed1996

Correction of congenital diaphragmatic hernia in utero VIII: Response of the hypoplastic lung to tracheal occlusion.

Most fetuses with congenital diaphragmatic hernia (CDH) diagnosed before 24 weeks' gestation die despite optimal postnatal care. In fetuses with liver herniation into the chest, prenatal repair has not been successful. In the course of exploring the pathophysiology of CDH and its repair in fetal lambs, the authors found that obstructing the normal egress of fetal lung fluid enlarges developing fetal lungs, reduces the herniated viscera, and accelerates lung growth, resulting in improved pulmonary function after birth. They developed and tested experimentally a variety of methods to temporarily occlude the fetal trachea, allow fetal lung growth, and reverse the obstruction at birth. The authors applied this strategy of temporary tracheal occlusion in eight human fetuses with CDH and liver herniation at 25 to 28 weeks' gestation. With ongoing experimental and clinical experience, the technique of tracheal occlusion evolved from an internal plug (two patients) to an external clip (six patients), and a technique was developed for unplugging the trachea at the time of birth (Ex Utero Intrapartum Tracheoplasty [EXIT]). Two fetuses had a foam plug placed inside the trachea. The first showed dramatic lung growth in utero and survived; the second (who had a smaller plug to avoid tracheomalacia) showed no demonstrable lung growth and died at birth. Two fetuses had external spring-loaded aneurysm clips placed on the trachea; one was aborted due to tocolytic failure, and the other showed no lung growth (presumed leak) and died 3 months after birth. Four fetuses had metal clips placed on the trachea. All showed dramatic lung growth in utero, with reversal of pulmonary hypoplasia documented after birth. However, all died of nonpulmonary causes. Temporary occlusion of the fetal trachea accelerates fetal lung growth and ameliorates the often fatal pulmonary hypoplasia associated with severe CDH. Although the strategy is physiologically sound and technically feasible, complications encountered during the evolution of these techniques have limited the survival rate. Further evolution of this technique is required before it can be recommended as therapy for fetal pulmonary hypoplasia.

Animals↗

PubMed1989

Respiratory muscle weakness in the Lambert-Eaton myasthenic syndrome.

Respiratory muscle function was assessed in six patients with the Lambert-Eaton myasthenic syndrome. Five had histologically proved small cell carcinoma of the lung; the sixth later developed metastases from an unknown primary site. Two patients had ventilatory failure, one without respiratory symptoms; another, who had emphysema, had dyspnoea and orthopnoea. The remaining three patients had no respiratory symptoms. Four patients had limb muscle weakness as judged by the maximal voluntary contraction of the quadriceps muscle (range for all subjects 32-100% predicted). Transdiaphragmatic pressure (Pdi) was measured during a maximal unoccluded sniff (Pdi: sniff), a maximal sustained inspiratory effort against a closed airway (Pdi: Pimax), and phrenic nerve stimulation (Pdi: twitch). Mild to moderate diaphragmatic weakness was present in all six patients in proportion to the degree of leg weakness (Pdi: sniff 30-64% predicted; r = 0.6; Pdi:Pimax 6-69% predicted, r = 0.8); this was associated with very low or absent Pdi:twitch during phrenic nerve stimulation. Four patients had weakness of the expiratory muscles. Improvement in muscle strength was documented in two patients after tumour chemotherapy and specific treatment with 3,4-diaminopyridine and prednisolone; one patient was still alive five years from first diagnosis. It is concluded that the respiratory muscles may be implicated in this condition more often than has previously been recognised. As the lack of mobility may cause respiratory symptoms to be minimised, the presence of respiratory muscle weakness may remain undiagnosed unless formal measurement of respiratory muscle function is made.

Autoimmune Diseases↗

PubMed1984

Reoperation for correction of anomalous origin of the left coronary artery from the pulmonary artery with return of left ventricular function.

An adult patient is presented in whom anomalous origin of the left coronary artery from the pulmonary artery was diagnosed in infancy. Initial treatment included a palliative poudrage procedure. Resulting widespread, dense adhesions were encountered during reoperation in adulthood and precluded direct reimplantation of the left coronary artery into the aorta. Instead, a tunnel within the pulmonary artery was constructed from the aorta to the left coronary ostium using a baffle of woven Dacron. Preoperative and postoperative studies showed improvement in ejection fraction and resolution of diaphragmatic hypokinesis.

Adult↗

PubMed1993

The Swedish modification of the tracheostomy tube to permit speech.

Over the last 20 years the Respiratory Unit at Danderyd Hospital, Sweden has treated and rehabilitated more than 90 patients on domiciliary ventilation, the majority of whom require night-time ventilation. Sixteen patients (11 men and 5 women) with high spinal cord lesions have been treated. Of these 16 patients, 9 are using diaphragmatic pacing. Every patient has a customised tube. If the patient can use diaphragmatic pacing the tube, as a rule, is single fenestrated. In patients using the ventilator full time, the tube is made to fit snugly in the trachea. When such a tube fits 'as a bullet in its tube' there is no need for a cuff. The patient has adequate ventilation and the small leak around the tube also permits good speech function. Sometimes a PEEP-valve is used to get a better voice.

Female↗