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PubMed2000

Effect of xenon on diaphragmatic contractility in dogs.

PURPOSE: This study was undertaken to examine the effect of xenon on diaphragmatic contractility in pentobarbitone- anesthetized, mechanically ventilated dogs. METHODS: Twenty-one dogs were randomly allocated to three groups (n=7 of each): Group I received oxygen 100%; Group II received xenon 30% in oxygen; Group III received xenon 60% in oxygen. Diaphragmatic contractility was assessed by measuring transdiaphragmatic pressure (Pdi) generated during supramaximal stimulation of phrenic nerves at the neck at low-frequency (20-Hz) and high-frequency (100-Hz) stimulation, after maintaining 60 min of stable condition. RESULTS: With inhalation of xenon at two different concentration (30% and 60%), no changes were observed in Pdi at either concentration. There was no difference in Pdi among the three groups. CONCLUSION: Increasing the concentration of xenon to 60% has no effect on diaphragmatic contractility in dogs. This suggests that xenon may be used safely as an anesthetic with respect to respiratory muscle function.

Anesthetics, Inhalation↗
PubMed1986

Theophylline in chronic obstructive pulmonary disease.

Although prolonged use of maintenance theophylline therapy in chronic obstructive lung disease remains controversial, evidence from well-designed studies indicates that it produces patient improvement as gauged by both objective and subjective measurements. An important reason to use sustained-release theophylline is to prevent episodes of bronchospasm by providing a smooth around-the-clock bronchodilator effect and thus reducing the need for periodic aerosolized beta agonists. Theophylline also increases diaphragmatic contractility and endurance, although there is disagreement concerning the practical clinical significance of this effect. The drug improves cardiovascular function by increasing myocardial contractility and by reducing pulmonary and systemic vascular resistances. The increased central respiratory drive produced by theophylline may be important in reducing the ventilatory depressant effects of oxygen therapy. The drug also acts to inhibit mediator release and improves several aspects of mucociliary function, although, again, the clinical significance of these actions has not been established.

Adrenergic beta-Agonists↗
PubMed1996

Long-term pulmonary sequelae in survivors of congenital diaphragmatic defects.

Between 1948 and 1980, 107 of 164 patients survived after repair of a congenital diaphragmatic defect. Sixty of the survivors (mean age, 29.6 years; SD, 9.0 years) underwent clinical examination, chest radiography, spirometry, and diffusing capacity measurement 11 to 41 years after the diaphragmatic repair. Twenty-seven of the 60 had body plethysmography, xenon 133 radiospirometry, and a test of bronchial hyperreactivity. Subjective physical performance was below average for eight patients (13%), seven patients (12%) had asthma, and four patients (7%) reported increased susceptibility to respiratory infections. Thirty-one patients (52%) had ventilatory impairment, which was obstructive in nine (15%), restrictive in seven (12%), and obstructive and restrictive in 15 patients (25%). Nine (35%) of the 26 patients tested had bronchial hyperreactivity. The presence of ventilatory impairment and bronchial hyperreactivity correlated with the initial clinical severity of the affliction. Chest asymmetry (29 patients; 48%) and scoliosis (16 patients; 27%) were more common among patients with ventilatory impairment than among those with normal spirometric findings. Ventilatory impairment and thoracic deformities are common in adults with repaired diaphragmatic defects. Surveillance should begin in infancy and continue into adulthood.

Adolescent↗
PubMed1990

Effect of extracorporeal membrane oxygenation on survival of infants with congenital diaphragmatic hernia.

To determine the effect of extracorporeal membrane oxygenation (ECMO) on the survival of infants with congenital diaphragmatic hernia, we undertook a retrospective review of 31 infants with congenital diaphragmatic hernia treated at Children's National Medical Center. Infants were categorized by means of the Bohn quadrant analysis to determine the impact of ECMO on infants with congenital diaphragmatic hernia and a "poor prognosis." All infants assigned to the Bohn 100% mortality quadrant required ECMO. The survival rate in this group was 86% (6/7) when assessed preoperatively and 67% (6/9) when assessed postoperatively. Comparison of the change occurring in ventilation index and arterial carbon dioxide pressure demonstrated that after repair the clinical condition of 48% of infants deteriorated, 40% improved, and 12% remained unchanged. Of the 12 infants whose condition was worse after surgery, 11 eventually required ECMO. Our review demonstrates that ECMO improved survival significantly in infants with congenital diaphragmatic hernia who had a "poor prognosis" by the criteria of Bohn et al. We recommend consideration of ECMO for all infants with congenital diaphragmatic hernia for whom maximal medical therapy has failed.

Evaluation Studies as Topic↗
PubMed1994

Tracheostomy ventilation versus diaphragmatic pacemaker ventilation in high spinal cord injury.

We have made a retrospective comparative study of patients with spinal cord injury, nine with a diaphragmatic pacemaker and 13 with mechanical ventilation. Clinical outcome, cost and subjective satisfaction with both modalities have been evaluated. The functional status was the same with both types of treatment. Proper management of an electric wheelchair and optimal phonation were attained, respectively, in 100% and 89% of pacers and in 77% and 77% of mechanically ventilated. The rate of hospital discharge and satisfaction with the treatment were significantly better for pacers. The time devoted to ventilatory assistance and cost were also more favourable in this group.

Adult↗
PubMed2000

Effects of positive end-expiratory pressure on diaphragm function.

Patients admitted to the PACU after surgery may require mechanical ventilation. Knowledge about the anatomy and physiology of the diaphragm and its association with ventilator modes may be helpful in the management of this patient. As the acuity of PACU patients increase, more patients may also be on higher levels of positive end-expiratory pressure (PEEP), requiring PACU nurses to understand the relationship between PEEP and diaphragm function to facilitate weaning. This article provides a review of the mechanical ventilation mode of PEEP and its relationship to diaphragmatic performance. The physiological effects associated with the use of PEEP are also reviewed.

Diaphragm↗
PubMed1976

[Results of the treatment of diaphragmatic lesions (author's transl)].

During the period of 1959 to 1975 34 patients were operated at the Chirurgische Universitatsklinik Koln-Lindenthal because of lesions of the diaphragm. From the survivors 20 patients were examined again 2 to 15 years after operation. 15 patients (75%) stated subjective complaints. On these patients cicatrizations in the sinus phrenicocostalis, higher position of the diaphragm, axial hernia of the hiatus, restricted flexibility of the diaphragm, flattened diaphragm and paralysis of the diaphragm were found. More than 50% of the patients showed a significantly restricted total and vital capacity. Most important was the fact that in 25% of the reexamined patients there existed an axial hernia of the hiatus caused by the trauma.

Adolescent↗
PubMed1982

Extracorporeal membrane oxygenation for newborn respiratory failure: forty-five cases.

Almost all types of newborn respiratory failure are reversible. However, supportive treatment (oxygen and positive airway pressure) can damage the lung, and newborn respiratory failure remains a major cause of morbidity and death in infants. Prolonged extracorporeal membrane oxygenation (ECMO) provides life support while allowing the lung to "rest." We have used ECMO in 45 moribund newborn infants; 25 survived. Neonatologists referred patients who were unresponsive to maximal therapy. The right atrium and aortic arch were cannulated via the jugular vein and carotid artery. Heparin was infused continuously to main activated clotting time at 200 to 300 seconds. Airway oxygenation and pressure were reduced to low levels. Primary diagnoses were hyaline membrane disease, 14 (6 survived, 8 died); meconium aspiration, 22 (15 survived, 7 died); persistent fetal circulation including diaphragmatic hernia, 5 (3 survived, 2 died); and sepsis, 4 (1 survived, 3 died). Growth, development, and brain and lung function are normal in 20 of 25 survivors. ECMO decreased newborn respiratory failure mortality and morbidity rates in this phase I trial. A controlled randomized study is underway. The results suggest that ECMO may be effective in older patients if used before irreversible lung damage occurs.

Bronchopulmonary Dysplasia↗
PubMed1982

[Diaphragmatic eventration in adults. Apropos of 20 cases].

Twenty adults with a mean age of 49 were operated on between 1972 and 1980 for eventration of the diaphragm. The etiology was probably traumatic in 11 cases; it was congenital in 2 and degenerative in 7. The functional signs were usually respiratory (55%) or digestive (10%). In all cases, the diagnosis was based on standard fluoroscopy showing superelevation of the hemidiaphragm, which was visualized fluoroscopically as immobile while a pneumoperitoneum showed a absense of any tear. Spirography confirmed a restrictive deficit which was sited broncho-spirometrically on the eventration side. Surgical repair was achieved in most cases by thoracotomy (19 cases) and consisted in plication (17 cases) or incision followed by suturing of the overlapping edges of the muscle (3 cases). Postoperative complications included the death of the patient with multiple trauma, on the eight postoperative day, as a result of the cerebrovascular accident, and in another case rutpure of the repair on the second day, requiring a second operation. Apart from one patient who died as a result of a fatal accident two years postoperatively, all the surgically treated cases are alive, and, with one exception, symptom free. After an average follow up period of 2 years and 2 months, the control respiratory function tests show a 21% improvement in vital capacity and a 20% increase in FEV1. On the basis of these results, the authors conclude that this functional surgery is justified in the case of patients presenting with typical clinical symptoms, and worth considering in cases where respiratory function tests show a restrictive deficit, but also in patients who do not complain of breathlessness.

Adult↗
PubMed1984

Relaxation rate of mouth pressure with sniffs at rest and with inspiratory muscle fatigue.

The relaxation rate of transdiaphragmatic pressure (Pdi) after voluntary contractions of the diaphragm slows with fatigue. We determined a range of values for the relaxation rate of mouth pressure (Pm) after voluntary contractions of the inspiratory muscles in 27 normal men and women at various lung volumes at rest. Values were similar for both sexes. The relaxation rates were similar at functional residual capacity (FRC) and below FRC, but were greater above FRC (p less than 0.05). In addition, we studied the effect of diaphragmatic fatigue induced by inspiratory resistive loading on the relaxation rates of Pdi and Pm with voluntary contractions of the inspiratory muscles in 6 subjects. With fatigue, the relaxation rates of Pdi and Pm both decreased by similar amounts, indicating that a decrease in the relaxation rate of Pm is as useful a predictor of inspiratory muscle fatigue as a decrease in the relaxation rate of Pdi has been shown to be for the diaphragm. The relaxation rate of Pm varies widely in normal subjects at rest, so isolated values do not indicate whether fatigue is present or developing. However, this may be predicted if relaxation rate decreases with serial measurements.

Adult↗
PubMed1996

Evolution of airway hyperresponsiveness in infants with severe congenital diaphragmatic hernia.

Infants born with severe congenital diaphragmatic hernia (DH) characteristically have pulmonary hypoplasia. Airway hyperresponsiveness during the first 4 weeks of life can be demonstrated in most of these neonates. Early postnatal pulmonary development in infants with severe DH has not been well characterized. We examined lung growth in patients with congenital DH by using the forced deflation method to study pulmonary function in 18 infants on mechanical ventilation who survived neonatal repair of their congenital DH. Thirteen infants without primary pulmonary pathology who required general anesthesia for other surgery served as controls. Infants were further divided according to age at the time of testing into early (age < or = 7 days at time of testing) and late (age > or = 29 days) groups, yielding four groups of subjects: early diaphragmatic hernia (EDH): n = 9; mean age, 4.2 days; range, 1-7 days; early controls (EC): n = 8; mean age, 3.1 days; range, 1-6 days; late diaphragmatic hernia (LDH): n = 11; mean age, 57.7 days, range, 28-120 days; and late controls (LC); n = 5; mean age, 52.2 days; range 32-90 days. All infants were studied once, with the exception of two infants with DH who were studied on two occasions at EDH and LDH stages. A marked reduction in weight-corrected forced vital capacity (FVC) was seen in the EDH group (13.9 +/- 3.9 ml/kg) as compared to the EC group (44.4 +/- 4.9 ml/kg). During the ensuing 4 months of life, FVC in patients with LDH (24.5 +/- 1.9 ml/kg) was much higher than FVC in patients with EDH (P < 0.05). These findings demonstrate the presence of pulmonary hypoplasia in the EDH group and suggest subsequent rapid postnatal lung growth. An index of rate constant, MEF25/FVC, as compared with control groups was abnormally elevated in EDH subjects (1.87 +/- 0.30/second vs 1.16 +/- 0.32/ second, P < 0.05), indicating significantly increased lower airway caliber relative to lung volume. The severe reduction of the rate constant in the LDH group (0.36 +/- 0.05/second vs 0.73 +/- 0.07/second, P < 0.05) suggests the development of lower airway obstruction. After the administration of a nebulized bronchodilator (BD), an increase in MEF25 (32.9%) in the EDH group was not significant, but an increase of 134.7% in the LDH group was significant (P < 0.05). Although the study utilized a cross-sectional design with most of the infants in either the early or late group, present findings suggest that infants with EDH have lung restriction reflecting pulmonary hypoplasia. These infants developed lower airway obstruction and airway hyperresponsiveness with only mild fixed obstruction over the first 4 months of life.

Airway Resistance↗
PubMed1988

[Influence of posture in respiratory function examination in obese subjects. II. In the patient with ventilation disorders].

On earlier occasions healthy subjects, and normal weight cold patients and obese subjects not suffering from hypoventilation were subjected to respiratory function tests in different postures using the plethysmographic and helium dilution methods. This protocol was then applied to a series of obese patients with the functional characteristics of alveolar hypoventilation identified in preliminary functional tests. The study revealed: a) significant differences between plethysmographic and helium dilution findings; b) not significant volumetric differences produces by different postures (standing or squatting) especially as far as Total Lung Capacity and the main lung volume parameters are concerned. These results confirm the findings of others (Sharp et al., 1986) that diaphragmatic adjustment to changes in posture is inadequate in the obese with bronchial obstruction in whom absence of the fibre-length compensation phrenophrenic reflex and by the muscle flattening cause by the alveolar hyperinsufflation. On the basis of these data and others already published an index of "diaphragmatic passivity" based on the ratio between TLC in squatting and TLC in standing x 100 is proposed as an indicator of the lung volume available for use. This simple system would indicate the functional condition of the diaphragm and provide information for the functional assessment of patients proposed for rehabilitation treatment during follow-up.

Adult↗
PubMed2004

Pax3 mRNA is decreased in the hearts of rats with experimental diaphragmatic hernia.

Rats with nitrofen-induced congenital diaphragmatic hernia (CDH) have heart hypoplasia and cardiovascular malformations. The mechanism of action of nitrofen involves changes in neural crest signaling. Pax3 function is required for cardiac neural crest cells to complete their migration to the developing heart. The aim of this study was to examine whether Pa x 3 expression is changed at two gestational endpoints in rat embryos or fetuses exposed to nitrofen. On day E9.5 of gestation, pregnant rats received either 100 mg of nitrofen (n=10) or vehicle alone (control, n=10). The fetuses were recovered on E15 or E21. Their hearts were dissected out and weighed. Pax3 mRNA expression was determined by real-time polymerase chain reaction. We used two-tailed Student's t-tests to compare groups, with a threshold of significance of p<0.05. Compared with controls, nitrofen-exposed fetuses had heart hypoplasia in terms of heart/body weight ratio (0.62+/-0.10% vs. 0.77+/-0.17%, p<0.05). Pax3 mRNA expression in the heart was significantly decreased on E15 in nitrofen-treated embryos (32.94+/-17.11 U vs. 55.09+/-11.56 U, p<0.05), and it was still decreased, although not significantly, in the hearts of nitrofen-exposed fetuses recovered on E21 (15.67+/-5.56 U vs. 20.51+/-5.92 U, not significant). In conclusion, Pax3 is underexpressed in the hearts of nitrofen-exposed embryonal rats before the end of gestation. The mechanism of action of Pax3 should be further investigated because it could be one of the targets for future prenatal transplacental intervention.

Animals↗
PubMed1998

Morphologic grading of the emphysematous lung and its relation to improvement after lung volume reduction surgery.

BACKGROUND: The morphologic criteria for lung volume reduction surgery, such as severity and heterogeneity of disease, differ widely between patients, and this makes any comparison of functional results between centers difficult. Here we present a morphologic scoring system and describe its possible relation to functional results after lung volume reduction operations. METHODS: Between September 1994 and December 1996, 47 consecutive patients underwent bilateral lung volume reduction operations. The morphology of emphysema was quantified with standard chest roentgenograms and computed tomographic imaging, which were used to define the following four variables: degree of hyperinflation (grade 0 to 4), degree of impairment in diaphragmatic mechanics, degree of heterogeneity (grade 0 to 4), and severity of parenchymal destruction (range, 0 to 48). RESULTS: All four variables showed good reproducibility. Degree of heterogeneity had a significant influence on functional improvement in terms of forced expiratory volume in 1 second (p = 0.0413, r2 = 0.11). Severity of parenchymal destruction was significantly associated with 30-day mortality: patients who died after operation (n = 4) had a severity of parenchymal destruction of 28.4 +/- 2.1 compared with 21.3 +/- 1.0 for those who survived (n = 43) (p = 0.003). CONCLUSIONS: This morphologic scoring system is easy to use, is reproducible, and allows quantification of the morphology of emphysema, thereby allowing definition of different patient subgroups. Such an exact morphologic quantification may help in the comparison of functional results between centers. Furthermore, the risk factors for certain morphologic subgroups, such as patients with a homogeneous distribution pattern, may be clarified in the future.

Adult↗
PubMed1986

Ovine congenital progressive muscular dystrophy: clinical syndrome and distribution of lesions.

The distribution and severity of lesions in the skeletal muscles of 37 Merino sheep with congenital progressive muscular dystrophy (CPMD) are described. An explanation for the clinical signs is offered on the basis of functional defects in regional muscle groups. Lesions in the extensors of the hip, stifle and hock joints and flexors of the digits are primarily responsible for the progressive abnormality of hind limb gait that is characteristic of the clinical syndrome. Lesions in extensors of the elbow and flexors of the shoulder, carpus and digits affected fore limb function in advanced cases. The tendency for some affected sheep to develop ruminal tympany is probably caused by lesions in the diaphragmatic crus. Clinically affected sheep had higher resting and post-exercise concentrations of serum creatine phosphokinase and lactic dehydrogenase than unaffected control sheep. The rise in serum creatine phosphokinase after exercise was greater in affected sheep than in controls. Myotonia was not demonstrated in electromyographic studies in one sheep.

Animals↗