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Results for “Diaphragmatic function”

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PubMed2002

Nitric oxide is not involved in the endotoxemia-induced alterations in Ca2+ and ryanodine responses in mouse diaphragms.

Lipopolysaccharide (LPS, endotoxin)-induced diaphragmatic contractile dysfunction and sarcolemmal injury in animals has been identified. However, the precise nature of sepsis-related alterations in diaphragm myofiber function and the activity of Ca(2+) release from sarcoplasmic reticulum of skeletal muscle remain unclear. The present study investigated the in vivo effects of LPS on the Ca(2+)-dependent mechanical activity and ryanodine response in mouse diaphragm and Ca(2+) release from isolated sarcoplasmic reticulum membrane vesicles, and aimed to examine the role of nitric oxide (NO) in these responses. When diaphragms were bathed in a solution that was Cl(-)-free, Na(+)-free, but contained high K(+), a Ca(2+)-induced contracture was elicited. Increases in external Ca(2+) concentration produced increases in peak tension of Ca(2+)-induced contracture in control diaphragm, while a decrease was seen in endotoxemic diaphragm. Ryanodine induced a marked contracture in control diaphragms, which was diminished after endotoxemia. This finding is correlated with the decrease of ryanodine-induced Ca(2+) release and the suppression of [(3)H]ryanodine binding on the isolated SR of the skeletal muscle from LPS-treated rats. In mice treated with LPS significantly increased levels of plasma nitrite and serum TNF-alpha were observed, changes inhibited by aminoguanidine [an inhibitor of inducible NO synthase (iNOS)] and pentoxifylline (an inhibitor of tumor necrosis factor-alpha formation), respectively. Moreover, LPS treatment resulted in a significant expression of mRNA for iNOS in mouse diaphragms. The inhibitory effects on Ca(2+)- and ryanodine responses by LPS could be prevented by treatment with polymyxin B (LPS neutralizer) and pentoxifylline, but not by treatment with dexamethasone, N(G)-nitro- L-arginine or aminoguanidine (NOS inhibitors). These results imply that the NO-related pathway may not be involved in the dysfunction of the Ca(2+) release mechanism in the sarcoplasmic reticulum of mouse diaphragm during endotoxemia.

Animals↗

PubMed2001

Effects of muscle group recruitment on sniff transdiaphragmatic pressure and its components.

Measuring maximal sniff pressures is an easy way of assessing inspiratory muscle strength. During a static manoeuvre, the pattern of inspiratory muscle recruitment during a sniff can vary from one individual to another. We therefore assessed how voluntarily changing muscle recruitment would affect sniff oesophageal, gastric and transdiaphragmatic pressures (Pes,sn, Pga,sn and Pdi,sn, respectively). Ten normal subjects (age 27-38 years) performed natural sniff manoeuvres ("nat"), and preferentially diaphragmatic ("dia") or extradiaphragmatic ("extradia") sniff manoeuvres, after having learnt to dissociate between the inspiratory muscle groups. Abdominal displacements were monitored using a belt-mounted strain gauge. Natural patterns of muscle recruitment varied among subjects. On average, Pes,sn,nat was [median (range)] 81 (21-105) cmH2O. All of the subjects were able to modify inspiratory muscle recruitment voluntarily. Pes,sn was not significantly affected by the type of manoeuvre performed, as opposed to Pdi,sn, which, as expected, increased with both the diaphragmatic and extradiaphragmatic manoeuvres [Pdi,sn,dia 132 (99-157) cmH2O, Pdi,sn,extradia 96 (50-146) cmH2O, P<0.05]. Whatever the manoeuvre, there was no correlation between Pes and Pdi, but Pga and Pdi were correlated during both the diaphragmatic (r = 0.82, P < 0.05) and the extradiaphragmatic manoeuvre (r = 0.70, P < 0.05). Pes,sn may have limitations as an index of diaphragm function, but by showing its independence from inspiratory muscle recruitment, this study contributes to its validation as a robust index of global inspiratory muscle strength that is particularly well suited for follow-up studies. This should extend to Pes,sn substitutes measured at the airway opening.

Abdominal Muscles↗

PubMed2006

Quantitative analysis of the velocity and synchronicity of diaphragmatic motion: dynamic MRI in different postures.

The objectives of this study were to assess the relationship between right and left hemidiaphragmatic motions during breathing in normal subjects and to investigate alterations in lung motion with changes in posture, using dynamic magnetic resonance (MR) imaging. Imaging was conducted with a 1.5-T MR scanner using fast imaging employing steady-state acquisition with a torso coil. Eight healthy subjects were instructed to breathe from end-inspiration to end-expiration as slowly and as deeply as possible. Imaging and breathing were started together to afford sequential images on the coronal plane. Imaging sequences were performed in supine, prone, left lateral decubitus and right lateral decubitus postures. The component of movement of the most cephalic point in the cephalocaudal axis was measured, and the diaphragmatic excursion (maximum hemidiaphragmatic displacement), synchrony and velocity of the right and left hemidiaphragmatic motions were calculated during the expiratory phase and the inspiratory phase, respectively. Excursion was greater in the right hemidiaphragm in most postures, except the left lateral decubitus. In supine and prone postures, both hemidiaphragms moved synchronously in both inspiratory and expiratory phases. In both lateral decubitus postures, the hemidiaphragms moved asynchronously with different velocities in the expiratory phase but with the same velocities in the inspiratory phase. The method described here allowed the assessment of diaphragmatic motions. Motions in the right and left hemidiaphragms changed with posture. In addition, diaphragmatic motion differed between expiratory and inspiratory phases. This study suggests the further potential of dynamic MR imaging for the evaluation of pulmonary functions or deficiencies.

Adult↗

PubMed1976

Myofeedback: a new method of teaching breathing exercises in emphysematous patients.

The diaphragm of the emphysematous patient is low and limited in its excursions, producing an increased functional residual capacity and decreased pulmonary ventilation. This report describes our experiences with a new technique for 1) the training of abdominal-diaphragmatic (A-D) breathing and 2) the relaxation of accessory respiratory muscles in emphysematous patients. Abdominal muscle contraction during expiration has been shown to increase diaphragmatic excursions and, hence, pulmonary ventilation. Use of this technique has been limited, however, because of the difficulty in learning this breathing pattern. Through continuous audio and visual feedback of myoelectric potentials (myofeedback) from abdominal muscles, 12 patients learned A-D breathing. The lower rectus abdominis muscle was found to be the most suitable muscle for obtaining the myoelectric potentials. Similarly, by providing the patients with myofeedback from their accessory muscles, they decreased the use of these muscles, thus increasing their respiratory efficiency. With myofeedback, patients appear to learn new breathing patterns effectively and in fewer sessions than with conventional procedures.

Abdominal Muscles↗

PubMed1997

Assessment and management of dyspnoea.

The terms 'dyspnoea' or 'breathlessness' refer to an individual's subjective awareness of discomfort related to the act of breathing. Elevations in CO2 above normal levels have been shown to cause breathlessness although it is unlikely to be the sole cause of breathlessness in a clinical setting. Several studies suggest that supplemental O2 during exercise will diminish the sensation of breathlessness although not all work has confirmed this finding. Much about the role of gas exchange in dyspnogenesis remains controversial. Phrenic blockade can abolish dyspnoea in response to breath-holding, while work in quadriplegics suggests that the intercostal muscles are not involved. A separate and direct pathway from the respiratory centre to the sensory cortex has also be implicated. Threshold discrimination has established that patients with chronic airflow limitation (CAL) have a blunted response to the addition of resistive loads to breathing, while category scaling methods (e.g. the Borg scale) have added descriptive terms to these physiological measures. Questionnaires often appear limited by their subjectivity and lack of correlation with physiological changes, but remain a useful tool in the clinical setting. In regard to therapy of dyspnoea high fat diets have a theoretical advantage in the CAL group but are generally not well tolerated. Resistive training devices and exercise training in CAL have been widely researched but in general, measures of lung remain unaltered and many of the studies would suggest that they have little, if any, inpact on functional status. Beta-agonists have been widely shown to be useful in CAL patients, despite the fact that bronchodilatation is not always demonstrable. Anticholinergics have be shown to be effective bronchodilators, but whether there is an improvement in dyspnoea above that expected from improvement in lung function is unclear. Animal studies and work in normal individuals would suggest that methylxanthines have a theoretical role in CAL possibly by increasing diaphragmatic muscle strength and decaying fatigue, but toxicity and lack of clear benefit in this group suggest that they should not be used as monotherapy. There is little evidence to support the use of opioids in chronic CAL although their role in the acute dyspnoea of end-stage CAL remains defined. The use of benzodiazepines has also been disappointing. Bullectomy remains widely accepted in clinical practice. New techniques such as 'reduction surgery' for diffuse emphysema are showing promise, although still in need of further testing and validation.

Carotid Body↗

PubMedDate not supplied

The role of hiatus hernia in GERD.

Increased esophageal acid exposure in gastroesophageal reflux disease has several potential causes, some related primarily to physiological dysfunction of the LES and others related to anatomic distortion of the gastroesophageal junction as occurs with hiatus hernia. One attractive feature of implicating hiatal hernias in the pathogenesis of reflux disease is that, like reflux disease, axial hernias become more common with age and obesity. However, the importance of hiatus hernia is obscured by imprecise definition and an all-or-none conceptualization that has led to wide variation in estimates of prevalence among normal or diseased populations. There are at least three potentially significant radiographic features of a hiatus hernia: axial length during distention, axial length at rest, and competence of the diaphragmatic hiatus. Although any or all of these features may be abnormal in a particular instance of hiatus hernia, each is of different functional significance. Grouping all abnormalities of the gastroesophageal junction as "hiatus hernia" without detailing the specifics of each case defies logic. Mechanistically, the gastroesophageal junction must protect against reflux both in static and dynamic conditions. During abrupt increases in intra-abdominal pressure, the crural diaphragm normally serves as a "second sphincter," and this mechanism is substantially impaired in individuals with a gaping hiatus. Large, non-reducing hernias also impair the process of esophageal emptying, thereby prolonging acid clearance time following a reflux event (especially while in the supine posture). These anatomically-determined functional impairments of the gastroesophageal junction lead to increased esophageal acid exposure. Thus, although hiatus hernia may or may not be an initiating factor at the inception of reflux disease, it clearly can act as a sustaining factor accounting for the frequently observed chronicity of the disease.

Diaphragm↗

PubMedDate not supplied

GERD revisited: advances in pathogenesis.

A balance of aggressive forces (reflux, caustic gastric juice) and defensive forces (acid clearance, epithelial defense) determine the occurrence of GERD. Guarding against reflux, the gastroesophageal junction is composed of both a smooth muscle element (the LES) and a diaphragmatic element, which normally supplement each other in both a static condition as well as during dynamic stresses associated with increased intraabdominal pressure or swallowing. With a normal LES pressure, virtually all reflux events occur by tLESR. Susceptibility to stress reflux (abrupt increase in intraabdominal pressure) inherent during periods of diminished LES pressure is dramatically increased by disabling the diaphragmatic sphincter, as occurs with large hernias. During swallowing, large hernias also impair the process of esophageal emptying thereby prolonging acid clearance. These functional impairments of the gastroesophageal junction associated with hiatus hernia lead to increased esophageal acid exposure and offer one explanation for the chronicity of reflux disease.

Esophagitis, Peptic↗

PubMed1993

[Respiratory function in massive obesity].

Massive obesity may be accompanied by severe and sometimes lethal respiratory complications. The restrictive ventilatory deficit which results from a decrease in thoracic wall compliance and perhaps also from diaphragmatic dysfunction is more severe in males and in subjects with abdominal obesity. Diurnal hypoxaemia results from 2 mechanisms: diminution of the ventilation/perfusion ratio at the base of the lung, and alveolar hypoventilation. Hypercapnia is a fairly frequent complication of massive obesity. Although usually moderate, hypercapnia is a major indicator as it is very often associated with sleep apnoea syndrome. The most severe respiratory complication of massive obesity is this syndrome which must be looked for systematically by questioning the patient and her husband or his wife before serious cardiopulmonary and neuropsychic disorders appear. The effects of weight loss of nocturnal apnoea are inconsistent and variable. Continuous positive pressure ventilation by means of a nasal mask is the choice treatment of sleep apnoea syndrome, especially since the results of rhino-laryngeal surgery are often disappointing.

Female↗

PubMed1997

Neuromuscular blockade with acute respiratory failure in a patient receiving cibenzoline.

Cibenzoline is a class Ic antiarrhythmic agent that can be used to treat supraventricular arrhythmias. A case is reported of cibenzoline overdose in a patient with impaired renal function, leading not only to the usual cardiac and metabolic symptoms (bradycardia and hypoglycaemia), but also to a myastheniform syndrome with acute respiratory failure. Neuromuscular blockade was demonstrated by repetitive supramaximal stimulation of the median nerve, and diaphragmatic involvement was evidenced by applying the same protocol to the phrenic nerve. Muscle strength recovered as serum cibenzoline levels decreased, allowing the patient to be weaned from the ventilator. This observation suggests that cibenzoline, like other antiarrhythmic agents, can be responsible for neuromuscular blockade, and should therefore be used with caution in patients with neuromuscular and respiratory diseases or with impaired renal function.

Acute Disease↗

PubMed1996

Fetal surgical interventions and the development of the heart in congenital diaphragmatic hernia.

Selective left ventricular hypoplasia is a recognized feature of congenital diaphragmatic hernia (CDH). It is speculated that the herniated viscera act as a space occupying lesion that inhibit normal cardiac development. The purpose of this study was to determine the effect of two separate fetal surgical interventions on subsequent cardiac development in CDH. CDH lambs were created at 80 days gestation and underwent either tracheal ligation (CDH + TL) or diaphragmatic repair (CDH + repair) at 110 days gestation. At term (141 days gestation) the hearts were harvested and fixed in 4% paraformaldehyde solution. Anatomic dissections were performed and component heart weights determined. Fresh specimens were analyzed for DNA and protein content. All weights are expressed in grams/kilogram body weight and all data as mean +/- SEM. All measurements are compared to control and CDH tissues. There were seven CDH lambs, five control lambs, five CDH + TL lambs, and five CDH + repair lambs. There were no differences in body weight (kg) between CDH, CDH + TL, CDH + repair, and control littermates. CDH lambs have significantly decreased total heart (4.88 +/- .25* vs 6.75 +/- .49, P < 0.05), left ventricular (1.65 +/- .11* vs 2.15 +/- .19, P < 0.05), septal (1.29 +/- .11* vs 1.99 +/- .21, P < 0.05), and combined atrial (0.68 +/- .06* vs 1.14 +/- .15, P < 0.05) weights (g/kg lamb) without differences in RV weights (1.26 +/- .07 vs 1.57 +/- .17, P = NS) when compared to littermate controls. No differences were found in total heart (4.82 +/- 0.38 vs 4.88 +/- 0.25), left ventricular (1.48 +/- 0.13 vs 1.65 +/- 0.11), septal (1.26 +/- 0.17 vs 1.29 +/- 0.11), combined atrial weights (0.56 +/- 0.07 vs 0.68 +/- 0.06), and right ventricular (1.52 +/- 0.12 vs 1.26 +/- 0.07) between CDH + TL and CDH lambs. There were no differences in total heart (6.60 +/- 0.29 vs 6.75 +/- 0.49), left ventricular (2.10 +/- 0.15 vs 2.15 +/- 0.19), septal (1.97 +/- 0.18 vs 1.99 +/- 0.21), combined atrial (1.10 +/- 0.10 vs 1.14 +/- 0.15), or right ventricular (1.52 +/- 0.12 vs 1.57 +/- 0.17) weights between CDH + repair and control lambs. LV and RV wall thicknesses (cm), as well as total protein and DNA content, and DNA/total protein ratios were identical in all groups. CDH lambs have a significant reduction in total heart weights mainly caused by hypoplasia of the left ventricle (left ventricular "smallness") and the interventricular septum. Removal of the herniated viscera and repair of the diaphragmatic defect correct this abnormality, but tracheal ligation does not. We speculate that although tracheal ligation reverses pulmonary hypoplasia, the enlarging lungs act as space occupying lesions that adversely affect cardiac development. Further investigations are necessary to determine the functional significance of these findings.

Animals↗

PubMed1988

The effect of gavage feeding on the mechanics of the lung, chest wall, and diaphragm of preterm infants.

Preterm infants when given bolus nasogastric (gavage) feedings have well-characterized decreases in arterial partial pressure of oxygen, increases in arterial partial pressure of carbon dioxide, a tendency to have apnea, and are reported to have no change in the mechanics of breathing. The purpose of this study was to assess the function of the lungs, chest wall, and diaphragm in preterm infants without lung disease before and after gavage feeding. Lung mechanics were measured with a pneumotachograph and esophageal balloon, and the mechanics of the chest wall and diaphragm were assessed by inductance plethysmography and measurement of transdiaphragmatic pressure. After feeding, there was a significant decrease in dynamic lung compliance and increase in the minute ventilation (p less than 0.05). The work performed on the lungs was unchanged. The chest wall became more stable, with a significant decrease in its dynamic compliance (p less than 0.05). The diaphragmatic volume displacement, expressed as a percentage of the minute ventilation, was unchanged. The diaphragmatic work increased significantly (p less than 0.05), and was greater than four times the work performed on the lungs. These results are consistent with previous reports of a decrease in functional residual capacity after feeding. The mechanical stability of the chest wall may have been improved by an increase in the area of apposition of the diaphragm to it, or by an increase in the central drive to breathing after feeding.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗

PubMedDate not supplied

Homologous dura mater used to close thoracic wall and diaphragmatic defects.

We have reported the successful use of homologous dura mater preserved in glycerin at room temperature to repair large defects of the thoracic wall or diaphragm in five patients. The surgical technic involved the use of autologous bone grafts in order to stabilize the thoracic cage in one case, but in the other four the dural blade was sufficient. The postoperative course was uneventful regarding the structure and function of the dural implant in each case.

Adult↗

PubMed1985

Pregnancy after renal transplantation.

During the 13 year period 1971 to 1984 there were 38 pregnancies in 21 renal transplant patients at the Johannesburg Hospital. Twenty-two ended with live births and included two sets of twins; there were nine spontaneous abortions, six therapeutic abortions, and one stillbirth. Maternal complications were mild in the majority but five patients suffered deterioration in renal function, two undergoing transplant nephrectomy as a result of this. There were seven neonatal deaths, including both sets of twins; death was due to prematurity in six and congenital malformation (diaphragmatic hernia) in one. A further infant had congenital pyloric stenosis which was corrected surgically. Pregnancies were analysed according to whether or not their outcome was successful. Those with a successful outcome had less exposure to warfarin during pregnancy (p = 0.0025) and showed a tendency towards lower immunosuppressive doses of prednisone and azathioprine although these did not reach significance. Although these results indicate an unhappy prognosis for both the mother and fetus, two redeeming features are to be noted. Pregnancy outcome improved markedly in the latter years, possibly owing to non-exposure to warfarin, less immunosuppression, and improvement in neonatal care, and four of the five mothers who suffered deterioration in renal function were notoriously unco-operative in their medical care. Pregnancy can only be recommended in the transplanted patient who has stable renal function, is compliant in taking of medications, and whose graft is of such age that the immunosuppressive drug dose is minimal. Warfarin should be avoided.

Abnormalities, Drug-Induced↗

PubMed2006

Shrinking lung syndrome in a 14-year-old boy with systemic lupus erythematosus.

Pulmonary complications occur frequently in people with systemic lupus erythematosus. We report on an adolescent with an acute onset of dyspnea and pleuritic chest pain with severe restrictive lung physiology on pulmonary function testing (forced vital capacity, 20% of predicted) who had no evidence of parenchymal lung or pleural disease. He was found to have restricted diaphragmatic movement as assessed by fluoroscopy, without evidence of generalized respiratory muscle weakness. His clinical presentation and results of diagnostic tests were typical for shrinking lung syndrome. Given the rarity of shrinking lung syndrome in the pediatric age range, many clinicians are not aware of it as a clinical entity. Shrinking lung syndrome should be included in the differential diagnosis of dyspnea in both children and adults with systemic lupus erythematosus.

Adolescent↗

PubMed2005

Effects of surgical repair of congenital diaphragmatic hernia on cerebral hemodynamics evaluated by near-infrared spectroscopy.

BACKGROUND: Cardiorespiratory stabilization is recommended before surgical repair of congenital diaphragmatic hernia (CDH) because surgery may induce a transitory deterioration of chest compliance and gas exchange. It is not known if surgical intervention can affect cerebral circulation and oxygenation. AIM: The aim of the study was to assess noninvasively, by near-infrared spectroscopy, the possible changes in cerebral hemodynamics and oxygenation associated with surgical repair of CDH. SUBJECTS: Twenty-five newborns with severe CDH (birth weight, 3057 +/- 354 g; gestational age, 37.8 +/- 1.8 weeks; male/female newborns, 15/10; left/right CDH, 19/6) were sedated, paralyzed, and mechanically ventilated by conventional gentle ventilation and surgically corrected at a median age of 2.7 days (min-max, 2-14 days) after cardiorespiratory stabilization. METHODS: Heart rate (HR [beats per minute]), preductal transcutaneous oxygen saturation (tcSaO2 [%]), carbon dioxide tension (tcPCO2 [Torr]), and mean arterial blood pressure (mm Hg) were continuously monitored. Inspired fractional oxygen concentration (FIO2) was adjusted to maintain and preductal tcSaO2 of greater than 80%, whereas the ventilator's settings were kept unchanged throughout the surgical procedure. Cerebral hemodynamics was assessed by near-infrared spectroscopy (NIRO 300, Hamamatsu Photonics, Japan), recording continuously and noninvasively the relative changes in concentration of oxygenated (DeltaO2Hb [micromol/L]), deoxygenated (DeltaHHb [micromol/L]), and total (DeltatHb [micromol/L]) hemoglobin; the tissue oxygenation index (TOI [%]) was also calculated (TOI = O2Hb/O2Hb + HHb). Total hemoglobin concentration is considered to be representative of cerebral blood volume. Arterial blood gases were also measured at the beginning (T1) and at the end of surgery (T2). For all measurements, results at T1 and at T2, as well as the differences between T1 and T2, have been expressed as means or medians and SDs or 95% confidence intervals or ranges. The differences between T1 and T2 were considered statistically significant for a P value of less than .05 by the Student t test for paired values. RESULTS: At T1, mean tcSaO2% was 94.1 % (SD, 4.6) with a FIO2 of 0.25 (SD, 0.1); at T2, to obtain similar values of tcSaO2 (93.4%; SD, 4.4), it was necessary to increase the FIO2 to 0.37 (SD, 0.14; P < .001). Mean HR at T1 was 149.5 beats per minute (SD, 9.1) and increased significantly (P < .05) at T2 (165.2 beats per minute; SD, 14.2). Mean arterial blood pressure was 54.7 mm Hg (SD, 7.7) at T1 and did not change appreciably at T2 (55.6 mm Hg; SD, 8.1). Moreover, tcPCO2 did not change significantly during the procedure (mean tcPCO2 = 49.9 Torr [SD, 12.8] at T1 and 57.3 mm Hg [SD, 17.9] at T2). O2Hb and tHb decreased (P < .001 and <.005) and HHb increased (P < .05) significantly during the surgical procedure (mean Delta [SD]: DeltaO2Hb= -10.9 micromol/L [9.7], DeltatHb = -7.5 micromol/L [11.7], and DeltaHHb = -3.5 micromol/L [6.8]). Mean TOI was 70% at T1 (normal values >60%) and decreased significantly at T2 (mean DeltaTOI = -6.1% [SD, 10.6]). In all infants, the greatest changes occurred when the viscera were positioned into the abdomen. CONCLUSIONS: Notwithstanding the initial cardiorespiratory stabilization, surgical repair of CDH was associated with a rise in HR and oxygen requirement and a drop in cerebral tHb and O2Hb, suggesting a reduction in cerebral blood volume and oxygenation. These events were probably due to the combined effects of an increase in right to left shunting (as indicated by the increased oxygen requirement) and a decrease in venous return (possibly due to compression of the inferior vena cava by the viscera positioned into the abdomen). These preliminary results reinforce the importance of achieving a good cardiorespiratory stability before undertaking surgical correction of CDH to minimize the possible interference of the procedure with cerebral circulation and oxygenation.

Brain↗

PubMed2002

Presentation and prognosis of the shrinking lung syndrome in systemic lupus erythematosus.

BACKGROUND AND OBJECTIVES: Systemic lupus erythematosus (SLE) may affect all the components of the respiratory system, including upper airways, lung parenchyma, pulmonary vasculature, pleura, and respiratory muscles. The shrinking lung syndrome (SLS) is a rare complication of SLE. This study describes the presenting features, investigation findings, treatment measures, and outcome of 7 patients with SLE and SLS. METHODS: Five patients with SLE/SLE were chosen retrospectively by examination of patient records, and 2 patients were chosen prospectively. All patients attended St. Thomas' Hospital or the Royal London Hospital between 1984 and 2001, with a total population of 2650 patients with SLE. RESULTS: Clinical features included dyspnea and pleuritic chest pain. Chest x-ray films showed small but clear lung fields, or basal atelectasis, with diaphragmatic elevation. No evidence of major parenchymal lung or pleural disease was found on the computerized tomography scan. Lung volumes were reduced on pulmonary function testing (PFT) in a restrictive pattern. Treatment of SLS included theophylline, increase in corticosteroid dosage, and intensification of immunosuppressive medication to include methotrexate or cyclophosphamide. During follow-up, 5 of 7 patients showed objective evidence on PFT of stabilization or improvement. CONCLUSIONS: The long-term prognosis of our SLS patients was reasonable, highlighting the importance of establishing a correct diagnosis and in particular differentiating it from fibrosing lung disease. Immunosuppressive therapy was helpful in stabilizing SLS and improving respiratory symptoms and PFT in some cases. RELEVANCE: SLS represents a rare complication of SLE, and it is important to be aware of its presenting features and prognosis.

Adolescent↗

PubMed2003

Warning signs of imminent respiratory failure in neurological patients.

Critically ill neurological patients often need ventilatory assistance. After acute central nervous system insults, the inability to protect the airway and impaired central respiratory drive can only be managed with endotracheal intubation and mechanical ventilation. In patients with acute or worsening neuromuscular disorders, diaphragmatic failure and pronounced bulbar weakness may necessitate intubation to assist in the work of breathing or to prevent upper airway obstruction. Simple respiratory function tests performed at the bedside should be used to monitor patients with progressive neuromuscular respiratory insufficiency. Noninvasive positive pressure ventilation plays an important role in the management of respiratory failure in patients with neuromuscular respiratory failure, and its indications may be expanded in the future.

Adult↗

PubMed1999

Neural drive to the diaphragm after lung volume reduction surgery.

STUDY OBJECTIVES: The aim of this study was to investigate prospectively the changes in neural drive to the diaphragm in the first year after lung volume reduction surgery (LVRS) in patients with COPD. PATIENTS AND METHODS: In 14 patients with severe emphysema (mean +/- SD; age, 53.7 +/- 8.3 years; FEV(1), 0.64 +/- 0. 18 L; residual volume [RV], 5.33 +/- 1.25 L; PaO(2), 62.3 +/- 9.0 mm Hg; PaCO(2), 39.0 +/- 6.0 mm Hg), we assessed lung function, arterial blood gases, maximal exercise capacity (Wmax), and oxygen uptake (f1.gif" BORDER="0">O(2)max); intrinsic positive end-expiratory pressure (PEEPi); diaphragmatic strength (transdiaphragmatic pressure, Pdisniff) and endurance capacity (tlim); central diaphragmatic drive assessed by root mean square analysis of the esophageal electromyogram (rmsdia); and isotime dyspnea during loaded breathing tests (BS). RESULTS: Despite a significant increase (expressed as a percentage of baseline) in FEV(1) (40.6%) and a decrease in RV (30.0%) and PEEPi (75.7%) 1 month after LVRS, the improvements in Wmax (31.2%) and f1.gif" BORDER="0">O(2)max (13.7%); Pdisniff (25.4%) and tlim (64.9%); rmsdia (34.6%); and BS (21.7%) did not reach statistical significance (p < 0.05) until 6 months after LVRS. Arterial blood gases did not change significantly. Significant correlations were found between decrease in rmsdia and changes in PEEPi (r = 0.69), Wmax (r = -0.56), Pdisniff (r = -0.65), tlim (r = -0.59), and BS (r = 0.71) 6 months after LVRS. CONCLUSIONS: Our results show that LVRS is able to increase the efficacy of the respiratory pump and by this way reduce ventilatory drive and respiratory effort sensation.

Diaphragm↗