SEARCH · PubMed Health
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.
This report describes an unusual case of right-sided congenital diaphragmatic hernia discovered fortuitously in a 45-year-old woman. Herniation was characterized by intrathoracic protrusion of the right liver and other abdominal viscera, left intrahepatic biliary dilatation, and anicteric cholestasis. Surgical repair was performed.
The role of impairment of neuromuscular transmission in fatigued canine diaphragm was investigated by comparing the function of fatigued diaphragm with that of neuromuscular junction (NMJ)-blocked diaphragm. Diaphragmatic fatigue was produced by intermittent supramaximal stimulation of bilateral phrenic nerves. Partial NMJ blockade was obtained by vecuronium bromide administered intravenously. During control study, no fade was observed either in integrated diaphragmatic electric activity (Edi) or transdiaphragmatic pressure (Pdi). In fatigued diaphragm, Edi generated by 100 Hz showed a remarkable fade. The fade was prominent in high frequency fatigue. In NMJ-blocked diaphragm, fade was observed in Pdi as well as in Edi produced by 100 Hz. The fade of Edi by 100 Hz was prominent. In low frequency fatigue, both Pdi and Edi produced by 20 Hz test stimulation were significantly lower than control values. These results show that in addition to impairment of excitation-contraction coupling, neuromuscular blockade is involved, at least in part, in low frequency diaphragmatic fatigue.
The results of 373 lymphography examinations with radioactive lipiodol, conducted in 408 patients with Hodgkin's disease for diagnostic and prophylactic therapeutic purposes, during investigations carried out from 1966 to 1973 are analyzed. Tolerance was always excellent, especially from the hematological point of view. The efficacy of the procedure can be assessed by the fact that there were only 6% of failures (21/373) in glandular regions irradiated in this way for prophylactic purposes. Relapses occur more frequently in the inguino-iliac and lumbo-aortic regions than in the pelvic chains which were perfectly protected. This technique also enables both pelvic irradiation and ovarian protection in young women without any risk of failure. The procedure is particularly indicated in the following cases: supradiaphragmatic stages I and II, whatever the sex, and stage III especially in women. In sub-diaphragmatic stages I and II, it allows, in favourable cases, the ovarian function in women to remain intact by limiting external irradiation to invaded regions only.
Pulmonary function testing was performed just prior to extubation on 50 infants mechanically ventilated for treatment of respiratory distress syndrome. All infants were ready for extubation as defined by clinical criteria. Pulmonary mechanics and energetics were measured by a computerized technique that consists of a pneumotachometer to measure flow rates and an esophageal balloon and differential transducer to estimate transpulmonary pressure. Tidal volume, minute ventilation, dynamic lung compliance, pulmonary resistance, and resistive work of breathing were then calculated by high speed microcomputer processing. Successful extubation was defined as greater than 72 hours without respiratory decompensation requiring reinstitution of ventilatory support. Thirty-six (72%) infants were successfully extubated and 14 (28%) infants failed extubation. Infants in the success and failure groups were matched for birth weight, gestational age, age at study, weight at study, weight at study relative to birth weight, use of nasal continuous positive airway pressure (CPAP), and methylxanthines. No statistically significant differences in pulmonary mechanics were seen between the two groups. Data suggests that successful withdrawal of mechanical ventilation may be related to multiple factors such as central inspiratory drive, diaphragmatic endurance, and chest wall stability, in addition to improved lung mechanics. Pulmonary function testing criteria alone may not be useful in determining optimal timing of extubation in premature infants.
The best electromyographic (EMG) predictors of respiratory drive (P100), tidal volume (VT) and ventilation (VE) were determined from diaphragmatic (DI) and posterior cricoarytenoid (PCA) EMG measures in 8-48-day-old, anesthetized piglets. Progressive hypercapnia was employed to obtain a wide range of muscle activity. A custom-designed, microcomputer-based system was employed to measure the duration, peak amplitude, rate of rise (initial slope) as well as the summed total and initial (first 100 ms) EMG activity from the DI and the PCA. For each respiratory function, the following combinations of EMG measures were identified as significant predictors using regression analyses: (1) for P100, DI amplitude, PCA initial area and PCA rate of rise; (2) for VT, DI amplitude, PCA duration and DI duration; (3) for VE, DI amplitude, DI initial area, PCA initial area, PCA rate of rise, PCA duration, DI area and DI rate of rise. Thus, whereas the traditionally employed measure of DI amplitude is an important correlate of P100, VT or VE, a complete estimate of these respiratory functions requires the inclusion of initial EMG measures and duration.
In order to identify the precise location of the primary motor area for the diaphragm with respect to the classical motor homunculus, functional magnetic resonance imaging (fMRI) experiments were performed utilizing independent component-cross correlation- sequential epoch (ICS) analysis on a high-field (3.0 Tesla) system. Activations which correlated with voluntary diaphragmatic motion mapped onto the area anterolateral to that for voluntary hand motion (internal control in ICS analysis). Multiple subject analysis yielded the primary motor cortex for the diaphragm to be (+/-48, -4, 47) in the Talairach and Tournoux coordinates. The results were highly consistent with the previously reported cortical area for the diaphragm determined by transcranial electrical/magnetic stimulation.
An unusual case of a neonate with absent pericardium, left-sided diaphragmatic hernia, and hepatic hemangioendothelioma is described. The posterolateral diaphragmatic hernia was successfully repaired, and agenesis of the pericardium did not interfere with cardiac function postoperatively. The hepatic tumour was a coincidental radiological finding, while liver function and the biochemical profile were normal. We also present a review of the literature on congenital absence of the pericardium and conclude that all cases should be screened for cardiac and hepatic anomalies.
Fetal tracheal occlusion (TO) has been used to reverse the lung hypoplasia associated with congenital diaphragmatic hernia (CDH). However, TO has a detrimental effect on type II pneumocyte function and surfactant production. Previously, we have shown that in surgically created CDH lambs, TO improved markedly the response to resuscitation even though the lungs remain surfactant deficient. The goal of this investigation was to assess the effects of exogenous surfactant administered at birth to CDH lambs with or without fetal TO during 8 h of resuscitation. Lambs were divided into five groups: CDH, CDH+surfactant (SURF), CDH+TO, CDH+TO+SURF, and nonoperated controls. A left-sided CDH was created in fetal lambs at 80 d gestation. TO was performed at 108 d, and the lambs were delivered by hysterotomy at 136 d. Bovine lipid extract surfactant was administered before the first breath and again at 4 h of life. All CDH+SURF lambs, but only three of five CDH lambs, survived up to 8 h. When compared with the corresponding nonsurfactant-treated group, surfactant-treated CDH and CDH+TO lambs did not demonstrate improved alveolar-arterial oxygen gradients, pH, or Pco(2). In fact, in the CDH+TO group, surfactant treatment significantly worsened ventilation efficiency as measured by the ventilation efficiency index. The observed improvement in pulmonary compliance secondary to surfactant treatment was not significant. This investigation demonstrates that prophylactic surfactant treatment at birth does not improve gas exchange or ventilation efficiency in CDH lambs with or without TO.
Esophageal pressure generated during a maximal sniff (sniff Pes) was compared with mouth pressure generated during a maximal inspiration against a closed airway (Pimax) as a measure of global inspiratory muscle strength in 61 patients referred for investigation of respiratory muscle function. Transdiaphragmatic pressure (Pdi) was also measured during both maneuvers to compare maximal diaphragmatic strength. Sniff Pes (males, 68 +/- 27 cm H2O; normal greater than 53; females, 66 +/- 21; normal greater than 48) was greater than Pimax (males, 45 +/- 24 cm H2O; normal greater than 42; females, 42 +/- 24; normal greater than 17) in 55 of the 61 patients, both in absolute values and as a percentage of normal. In 36 patients Pimax and sniff Pes were both normal (mean +/- 2 SD), whereas in 13 patients they were both low. In 11 patients, Pimax was low, but sniff Pes was normal. One patient had a reduced sniff Pes but a Pimax at the lower limit of normal. In the 36 patients in whom both Pimax and sniff Pes were normal, Pdi was also normal or only moderately reduced, and in the 13 patients in whom both Pimax and sniff Pes were reduced, Pdi was very low. However, in the group of 11 patients with a low Pimax but a normal sniff Pes, Pdi was normal or only moderately reduced, suggesting that Pimax was falsely low, perhaps because of difficulties with the technique. Conversely, in the single patient with a low sniff Pes but a Pimax just within the normal range, Pdi was very low. We conclude that measurement of esophageal pressure during a maximal sniff is a useful test of inspiratory muscle strength and overcomes the difficulty some patients have in carrying out the Pimax maneuver.
Extracellular Ca2+ has been shown to be important for the normal function of the diaphragm. In this study we have examined the potential importance of Na(+)-Ca2+ exchange as a mechanism for Ca2+ influx during the contractile process by studying the effect of inhibition or stimulation of Na(+)-Ca2+ exchange. Blockade of Na(+)-Ca2+ exchange with amiloride attenuated the twitch response, altered the force-frequency response curve, and enhanced the development of fatigue. The effect of amiloride could be partially reversed by increasing the extracellular Ca2+ concentration. The ability of amiloride to decrease force was associated with decreased Ca2+ uptake by the diaphragm. Enhancing intracellular Na(+)-extracellular Ca2+ exchange by inhibiting the Na(+)-K+ pump significantly decreased the rate of the development of muscle fatigue (89%). The maximal inhibition of diaphragmatic force produced by the amiloride analogue benzamil, which possesses 10-fold greater selectivity for Na(+)-Ca2+ exchange, was not significantly different from that produced by amiloride (76.2 +/- 1.1%), with a concentration that decreased maximum force by 50% equal to 46 microM compared with 460 microM for amiloride. Both agents slowed the maximal rate of relaxation up to 90%. Benzamil elevated resting tension during continuous stimulation of the diaphragm at 0.15 Hz. The results suggest that Na(+)-Ca2+ exchange may have a role in the normal function of the diaphragm.
The antioxidant N-acetylcysteine (NAC) prevented sepsis-induced diaphragmatic dysfunction. As an indirect antioxidant NAC was shown to induce superoxide dismutase (SOD) activity in immune cells from endotoxaemic mice. The aim of this study was to assess whether NAC acts as an indirect antioxidant by inducing manganese (Mn)-SOD activity in the diaphragms of endotoxaemic rats, while preventing muscle dysfunction. A controlled study was conducted, in which protein carbonylation, Mn-SOD, catalase, and 3-nitrotyrosine immunoreactivity were detected using immunoblotting and immunohistochemistry in rat diaphragms. Six groups were studied for 24 h after a saline (control) or lipopolysaccharide (LPS; 20 mg.kg-1) i.p. injection in the absence and presence of NAC pre-treatment (either 1.5 or 3 mmol.kg(-1).24 h-1 for 7 days, oral administration). Diaphragm mitochondrial Mn-SOD activity and respiratory muscle function were also determined. Within 24 h, LPS induced maximal inspiratory pressure reduction, increasing diaphragmatic protein carbonylation and nitration. Pre-treatment with 3 mmol.kg-1 NAC clearly increased muscle Mn-SOD protein content and activity in both LPS- and saline-injected animals, while reducing protein carbonylation and nitration, and partially preventing the LPS-induced respiratory muscle dysfunction. Data produced from this study indicate that high doses of N-acetylcysteine induces manganese superoxide dismutase, as well as preserves its activity, possibly by preventing nitration of critical tyrosine residues of the enzyme.
The first-breath (neural) effects of graded resistive loads added separately during inspiration and expiration was studied in seven anesthetized cats before and after bilateral vagotomy. Additions of airflow resistance during inspiration reduced the volume inspired (VI) and increased inspiratory duration (TI). The duration of the ensuing unloaded expiration (TE) was unchanged. Vagotomy eliminated the TI modulation with inspiratory loads. Tracheal occlusion at the onset of inspiration yielded TI values similar to the fixed values observed following vagotomy. Resistive loads added during expiration produced similar results. Expired volume (VE) decreased and (TE) increased approaching the values obtained after vagotomy. Unlike the inspiratory resistive loads, loading during expiration results in an upward shift in the functional residual capacity (FRC). The FRC shift produces a time lag between the onset of diaphragmatic (EMG) activity and the initiation of airflow of the next (unloaded) inspiration. These studies suggest separate volume-time relationships for the inspiratory and expiratory phases of the breathing cycle. Both relationships are dependent upon vagally mediated volume feedback.
Some studies have suggested that protective mechanisms downregulate diaphragm activity during loaded breathing so as to prevent respiratory-muscle fatigue. Other work has indicated, however, that loading can sometimes elicit significant diaphragmatic fatigue, and that the development of fatigue may be related to alterations in diaphragmatic glutathione concentrations. One potential explanation for these discrepant observations is that the mechanism of respiratory failure may vary as a function of load magnitude, and that some loads evoke little fatigue whereas others produce substantial fatigue and glutathione alterations. The purpose of this study was to examine this issue by determining the diaphragmatic fatigue and alterations in glutathione concentrations produced by a range of inspiratory resistive loads. Experiments were performed on decerebrate rats divided into a control, unloaded group and a group loaded with small, medium, and large inspiratory resistive loads that were applied until respiratory failure occurred. After respiratory arrest, the animals' diaphragms were excised, an in vitro determination was done of diaphragm contractility characteristics, and samples of muscle were assayed for GSH (reduced glutathione) and GSSG (oxidized glutathione). We found that in vitro diaphragm force generation was severely reduced for loaded breathing, and surprisingly, that the magnitude of the low-frequency fatigue present was similar in the three loaded groups. Reductions in diaphragmatic GSH levels and increases in GSSG levels were found in all three loaded groups. Reductions in diaphragmatic GSH levels and increases in GSSG levels were found in all three loaded groups, but again, the magnitude of these changes were similar.(ABSTRACT TRUNCATED AT 250 WORDS)
For comparative assessment of some methods of surgical correction of the cardia the results of surgical treatment of 180 patients were analyzed. In 33 patients hiatal diaphragmatic hernia (HDH) was detected, in 84--duodenal ulcer was combined with HDH and in 63--duodenal ulcer was detected. In 15 patients operation by Hill was performed for correction of cardial function, in 9--operation by Dor was carried out, in 3--valvular gastroplication by N.N. Kanshin, in 23--esophagofundorrhaphy and in 130--modified by N. N. Kanshin and A. F. Chernousov fundoplication was performed. In 49 patients fundoplication by improved method was carried out with the use of intraoperative esophagomanometric control for adequacy of the procedure. The effectiveness of the treatment was evaluated according to the short-term and long-term results. It was thus established, that the best procedure of surgical correction of the cardia was fundoplication. Introduction of esophagomanometry during fundoplication valve formation is the most important factor contributing to adequate restoration of the cardia.
Active expiration is produced by the abdominal muscles and the rib cage expiratory muscles. We hypothesized that the relative contribution of these two groups to expiration would affect diaphragmatic length and, hence, influence the subsequent inspiration. To address this question we measured the respiratory muscle response to expiratory threshold loading in spontaneously breathing anesthetized dogs. Prevagotomy, the increase in lung volume (functional residual capacity) and decrease in initial resting length of the diaphragm were attenuated by greater than 50% of values predicted by the passive relationships. Diaphragmatic activation (electromyogram) increased and tidal volume (VT) was preserved. Postvagotomy, effective expiratory muscle recruitment was abolished. The triangularis sterni muscle remained active, and the increase in lung volume was attenuated by less than 15% of that predicted by the passive relationship. Diaphragmatic length was shorter than predicted. VT was not restored, even though costal diaphragmatic and parasternal intercostal electromyogram increased. During expiratory threshold loading with abdominal muscles resected and vagus intact, recruitment of the rib cage expiratory muscles produced a reduction in lung volume comparable with prevagotomy; however, diaphragmatic length decreased markedly. Both the rib cage and abdominal expiratory muscles may defend lung volume; however, their combined action is important to restore diaphragmatic initial length and, accordingly, to preserve VT.
The high incidence of respiratory symptoms in patients with reflux esophagitis reported in the literature supports a cause-effect relationship between esophageal reflux and pulmonary symptoms. Analysis of the results of routine preoperative pulmonary function tests on 90 patients with reflux esophagitis and on 277 patients having nonthoracic elective surgery revealed that although the incidence of obstructive lung disease was high in both groups, it was higher in the general surgical population (51.9%) than in the patients with reflux esophagitis (37.7%). Thus a cause-and-effect relationship cannot be established between reflux esophagitis and obstructive lung impairment. This study indicates that the incidence of significant obstructive lung impairment in the general surgical population is greatly underestimated.
Methotrexate (MTX) has been implicated as a cause of interstitial pneumonitis and/or fibrosis, but the mechanism by which the drug causes these processes is not known. The purpose of this study was to determine whether patients receiving high-dose MTX developed a consistent decrease in pulmonary function, which would implicate a role for total dose of MTX received in the pathogenesis of the lung toxicity. Pulmonary function studies, including spirometry, plethysmography, and diffusing capacity at two levels of alveolar PO2, were performed in 38 adolescents treated for osteogenic sarcoma. The patients were divided into three groups including 12 patients (group 1) studied before and during therapy, 15 patients (group 2) studied during therapy, and 11 patients (group 3) studied after completion of treatment. While total dose received at the time of the study varied from 0 to 256 gm/sq m, pulmonary function showed no change, with one exception. A mild restrictive defect and decrease in diffusing capacity due to unilateral pleural and diaphragmatic disease, whose relationship to MTX therapy is uncertain, developed in one patient. MTX, when administered in high dose to young patients by the described protocol, causes no dose-related decrease in pulmonary function.
BACKGROUND AND AIMS: Flow across the esophagogastric junction (EGJ) is strongly related to opening dimensions. This study aimed to determine whether opening of the relaxed EGJ was altered in patients with gastroesophageal reflux disease (GERD). METHODS: Seven normal subjects (NL), 9 GERD patients without hiatus hernia (NHH), and 7 with hiatus hernia (HH) were studied. Cross-sectional area (CSA) of the relaxed EGJ was measured during low-pressure distention using a modified barostat technique that resulted in filling a compliant bag straddling the EGJ with renograffin to the set pressure. Swallows were imaged fluoroscopically at distensive pressures of 2-12 mm Hg. The diameter of the narrowest point of the EGJ in PA and lateral projections was measured from digitized images. CSA was determined as a function of intrabag pressure. RESULTS: The minimal EGJ opening aperture occurred at the diaphragmatic hiatus in all subjects. At pressures </=0 mm Hg, EGJ opening was observed only in HH patients, making it plausible for these patients to reflux during deglutitive relaxation. At pressures >0 mm Hg, there were significant increases in EGJ CSA both for HH and NHH compared with NL (P < 0.001) and for HH compared with NHH (P < 0.005). This difference may explain the diminished air/water discrimination seen during transient lower esophageal sphincter (LES) relaxation-associated reflux in GERD patients. CONCLUSIONS: Anatomic degradation of the EGJ distinguishes GERD patients from normal subjects, and these changes may impact on both the observed mechanisms of reflux and the constituents of reflux during transient LES relaxation. Therapy focused on EGJ compliance may benefit GERD patients.