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PubMed2000

Assessment of corticodiaphragmatic pathway and pulmonary function in acute ischemic stroke patients.

This study investigates the effect of stroke on the corticodiaphragmatic pathway and attempts to clarify the relationship between neurophysiological data and degree of motor disability, site of infarction in computerized tomography (CT) scan, diaphragmatic excursion, blood gases and pulmonary function in stroke patients. Using magnetic stimulation of the scalp sites and cervical roots, an assessment of corticodiaphragmatic pathway was made. The study included 34 sequentially selected patients from a total of 250 patients with acute ischemic stroke. Twenty-five (age- and sex-matched) volunteers served as controls. Sixteen patients had cortical infarction, 13 had subcortical infarction and five had both cortical and subcortical infarction. The mean according to the Scandinavian Stroke Scale was 32.2. Decreased diaphragmatic excursion was observed in 41% of the patients. Twenty-four patients (70.5%) had abnormal magnetic evoked potentials (MEPs) in the affected hemisphere. In five patients MEPs could not be elicited from the affected hemisphere; the remaining 19 patients had abnormal values of both cortical latency and central conduction time (CCT). Cortical latency, CCT, amplitude of compound muscle action potentials (CMAPs) and excitability threshold of the affected hemisphere were significantly altered compared with both the unaffected hemisphere and the control group. Those patients with hemiplegia had a greater degree of hypoxia, hypocapnia and decreased serum bicarbonate level compared with the control group. Also, hemiplegic patients had different degree of respiratory dysfunction. A statistically significant association was found between neurophysiological data and disability score, diaphragmatic excursion, site of infarction in CT scan and degree of respiratory dysfunction. Central diaphragmatic impairment may occur in acute stroke and could contribute to the occurrence of hypoxia in those patients.

Action Potentials↗
PubMed2005

Rescue of the hypoplastic lung by prenatal cyclical strain.

We determined the effects of sustained and cyclical prenatal mechanical strain on the hypoplastic lung of the ovine model of congenital diaphragmatic hernia. Over a period of 4 weeks in late gestation, repeated cyclical tracheal occlusion for 23 hours with 1-hour release stimulated minimal growth, but promoted maturation with the development of a saccular lung. In contrast, a cycle consisting of 47 hours with 1-hour release induced optimal lung growth and morphologic maturation of the hypoplastic lung parenchyma. Sustained occlusion resulted in exaggerated lung growth, exceeding that of unaffected controls, and abnormal alveolar development. The extent of induction of lung growth by mechanical strain was inversely proportional to the number of alveolar type II cells remaining in the lung epithelium. These studies show that, although mechanical strain is capable of inducing lung growth and differentiation, cyclical strain is a prerequisite for normal development and that mechanically induced growth occurs at the expense of the alveolar type II cell. We conclude that cyclical strain may allow optimal alveolar development while maintaining a population of alveolar type II cells and may thus facilitate an improvement in postnatal lung function in infants with congenital diaphragmatic hernia.

Analysis of Variance↗
PubMed2000

Assessment of corticodiaphragmatic pathway and pulmonary function in acute ischemic stroke patients.

The aims of this study were to investigate the effect of stroke on the corticodiaphragmatic pathway and to clarify the relationships between neurophysiological data and degree of motor disability, site of infarction in CT scan, diaphragmatic excursion, blood gases and pulmonary function in stroke patients. The corticodiaphragmatic pathway was assessed using magnetic stimulation of the scalp sites and cervical roots. The study included 34 sequentially selected patients out of 250 patients with acute ischemic stroke. Twenty-five (age and sex matched) volunteers served as controls. Sixteen patients had cortical infarction, thirteen had subcortical infarction and five had both cortical and subcortical infarction. The mean Scandinavian Stroke Scale was 32.2. Decreased diaphragmatic excursion was observed in 41% of the patients. Twenty-four patients (70.5%) had abnormal magnetic evoked potentials (MEPs) of the affected hemisphere. In five patients MEPs were unelicitable from the affected hemisphere. The remaining nineteen patients had abnormal values of both cortical latency and central conduction time (CCT). Cortical latency, CCT, amplitude of compound muscle action potentials (CMAPs) and excitability threshold of the affected hemisphere were significantly altered compared to both the unaffected hemisphere and the control group. The patients with hemiplegia had a greater degree of hypoxia, hypocapnia and decreased serum bicarbonate level compared to the control group. Additionally, hemiplegic patients had a different degree of respiratory dysfunction. A statistically significant association was found between neurophysiological data and disability score, diaphragmatic excursion, site of infarction in CT scan and degree of respiratory dysfunction. Central diaphragmatic impairment may occur in acute stroke and could contribute to the occurrence of hypoxia in those patients.

Adult↗
PubMed2004

Accounting for center-of-mass target motion using convolution methods in Monte Carlo-based dose calculations of the lung.

We have applied convolution methods to account for some of the effects of respiratory induced motion in clinical treatment planning of the lung. The 3-D displacement of the GTV center-of-mass (COM) as determined from breath-hold exhale and inhale CT scans was used to approximate the breathing induced motion. The time-course of the GTV-COM was estimated using a probability distribution function (PDF) previously derived from diaphragmatic motion [Med. Phys. 26, 715-720 (1990)] but also used by others for treatment planning in the lung [Int. J. Radiat. Oncol., Biol., Phys. 53, 822-834 (2002); Med. Phys. 30, 1086-1095 (2003)]. We have implemented fluence and dose convolution methods within a Monte Carlo based dose calculation system with the intent of comparing these approaches for planning in the lung. All treatment plans in this study have been calculated with Monte Carlo using the breath-hold exhale CT data sets. An analysis of treatment plans for 3 patients showed substantial differences (hot and cold spots consistently greater than +/- 15%) between the motion convolved and static treatment plans. As fluence convolution accounts for the spatial variance of the dose distribution in the presence of tissue inhomogeneities, the doses were approximately 5% greater than those calculated with dose convolution in the vicinity of the lung. DVH differences between the static, fluence and dose convolved distributions for the CTV were relatively small, however, larger differences were observed for the PTV. An investigation of the effect of the breathing PDF asymmetry on the motion convolved dose distributions showed that reducing the asymmetry resulted in increased hot and cold spots in the motion convolved distributions relative to the static cases. In particular, changing from an asymmetric breathing function to one that is symmetric results in an increase in the hot/cold spots of +/- 15% relative to the static plan. This increase is not unexpected considering that the target spends relatively more time at inhale as the asymmetry decreases (note that the treatment plans were generated using the exhale CT scans).

Body Burden↗
PubMed1995

Pathophysiological response of bovine diaphragm function to gastric distension.

Because of the anatomic association of an exceptionally bulky stomach with a striking compartmentation of the chest wall, leading to the most cranial insertion of the diaphragm among mammals, gastric overdistension in the bovine species offers a unique pathophysiological condition for the diaphragm. The purpose of the present study was to determine whether increased intragastric pressure (Pga) (1, 2, 3, 4, and 5 kPa) leads to perturbations of respiratory and diaphragm function in calves. Changes in diaphragmatic strength and inspiratory action followed a biphasic pattern: 1) transdiaphragmatic pressure (Pdi) in response to constant bilateral maximal phrenic nerve stimulation at 30 Hz increased with moderate gastric distension and then fell abruptly as Pga continued to rise and 2) the magnitude of the ratio of the fall in pleural pressure to total Pdi was maintained up to a Pga amounting to 2 kPa but declined at higher pressures. We conclude that gastric distension in the bovine species provokes physiologically significant alterations of the diaphragm excitation-to-pressure generation coupling as well as of its capacity to convert Pdi into useful inspiratory pleural pressure. We suggest that these perturbations resulted from the combination of 1) altered tension-generating capacity due to compromised perfusion, 2) altered diaphragm geometry capable of altering tension-to-pressure generation coupling, and 3) modified coupling of the diaphragm with the chest wall that reduced its ability to drive inspiration.

Animals↗
PubMed2001

Electromyography of respiratory muscles in amyotrophic lateral sclerosis.

We reviewed the records of 52 amyotrophic lateral sclerosis (ALS) patients examined between 1995 and 2000 who had needle electromyography (EMG) of their respiratory muscles, including the diaphragm, at or near the time of their diagnosis. With respiratory function testing, patients with abnormal diaphragmatic EMG at diagnosis (Group 1, n=23) had significantly lower forced vital capacity (FVC), lower daytime arterial PO(2) and higher PCO(2) measurements (p<0.05) than patients with normal diaphragmatic EMG (Group 2, n=29). Twenty-eight percent of the patients without symptoms or signs of respiratory insufficiency at the time they were examined had an abnormal diaphragm EMG. Mean survival of Groups 1 and 2 were similar. However, sub-analysis of patients within each group, comparing those treated with non-invasive positive pressure ventilation (NIPPV) with those not treated, showed that treated patients in Group 1 (abnormal diaphragm EMG) survived significantly longer (p<0.05) than untreated patients. They also started NIPPV earlier than treated patients in Group 2. We conclude that respiratory muscle EMG was simply and safely performed on ALS patients at or around the time of diagnosis. The procedure can detect sub-clinical respiratory muscle dysfunction. The technique used for EMG of the respiratory muscles, its pitfalls and contraindications are also reviewed.

Aged↗
PubMed2006

Non-invasive ventilation corrects alveolar hypoventilation during spinal anesthesia.

PURPOSE: To document and explain the beneficial effects of non-invasive ventilation in correcting hypoxemia and hypoventilation in severe chronic obstructive pulmonary disease, during spinal anesthesia in the lithotomy position. CLINICAL FEATURES: A morbidly obese patient with severe chronic obstructive pulmonary disease underwent prostate surgery in the lithotomy position under spinal anesthesia. Hypoxemia was encountered during surgery, and a profound decrease of forced vital capacity associated with alveolar hypoventilation and ventilation/perfusion mismatching were observed. In the operating room, an M-mode sonographic study of the right diaphragm was performed, which confirmed that after spinal anesthesia and assuming the lithotomy position, there was a large decrease (-30%) in diaphragmatic excursion. Hypoxemia and alveolar hypoventilation were successfully treated with non-invasive positive pressure ventilation. CONCLUSIONS: Intraoperative application of non-invasive positive pressure ventilation improved diaphragmatic excursion and overall respiratory function, and reduced clinical discomfort in this patient.

Anesthesia, Spinal↗
PubMed2000

Feedback-controlled negative pressure ventilation in patients with stable severe hypercapnic chronic obstructive pulmonary disease.

BACKGROUND: In recent studies, the efficacy of intermittent rest of the inspiratory muscles as an option of treating patients with severe chronic obstructive pulmonary disease (COPD) has become questionable. OBJECTIVE: The aim of our study was to analyze the effects of feedback-controlled intermittent negative pressure ventilation (INPV) on stable, but severely hypercapnic COPD patients. METHODS: 21 clinically stable, hypercapnic patients with severe COPD underwent INPV with chest shells for 3 weeks, 6 h a day. The INPV sessions were optimized by a visual biofeedback system, which enabled control over the decrease in diaphragmatic activity. Respiratory muscle (RM) function parameters, lung function parameters, blood gases and exercise capacity were analyzed. RESULTS: In the end, 19 patients concluded INPV treatment. They had PaO(2) of 56.5 +/- 11.8 mm Hg, PaCO(2) of 50.2+/-2.7 mm Hg (mean +/- SD) and FEV(1) of 27.8 +/- 4.3% predicted before treatment. There was no statistically significant change in lung function parameters, RM function parameters, physical performance and level of dyspnea after 3 weeks of INPV. CONCLUSION: We conclude that intermittent RM rest induced by INPV can relax inspiratory muscles in most patients with stable severe COPD, but fails to improve RM function and exercise capacity.

Aged↗
PubMed1988

Respiratory pressure partitioning during quiet inspiration in unilateral and bilateral diaphragmatic weakness.

To compensate for diaphragmatic weakness, intercostal/accessory muscles may be recruited in inspiration and/or abdominal muscles in expiration with relaxation during subsequent inspiration. As a consequence, for a given decrease in pleural pressure (Ppl) during quiet inspiration (qi), abdominal pressure (Pab) should either undergo a smaller increase than normal or, in severe cases, decrease. If so, the ratio of change in Pab to Ppl during qi (delta Pab/delta Ppl(qi], which is normally less than -1 when upright, should increase, approaching +1 in profound diaphragmatic weakness. To examine the relationship between degree of diaphragmatic weakness and delta Pab/delta Ppl(qi), we measured (erect and supine) anteroposterior rib cage and abdominal motion, Pab, Ppl, and transdiaphragmatic pressure (Pdi) during qi, maximal inspiration (Pdi(max)mi) and maximal inspiratory effort at FRC (Pdi(max)FRC) in 10 patients with bilateral and 8 with unilateral diaphragmatic weakness. Pdi(max)mi and Pdi(max)FRC were low in all patients. delta Pab/delta Ppl(qi) (erect) was increased in all patients (0.28 +/- 0.7; mean +/- SD) and correlated closely with both Pdi(max)mi (r = -0.89, p less than 0.001) and Pdi(max)FRC (r = -0.76, p less than 0.001). There was extensive overlap in the data between unilateral and bilateral diaphragmatic weakness. The ratio of delta Pdi during qi to Pdi(max)FRC was less than 0.31 in all patients. The results suggest that delta Pab/delta Ppl(qi) is a useful index of the degree of diaphragmatic weakness and that the functional consequences of unilateral and bilateral weakness are not rigidly separable.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed2000

Detection of subclinical abdominal hernia by peritoneal scintigraphy.

This study investigated the incidence of subclinical abdominal hernia in patients starting peritoneal dialysis (PD). From April 1995 to August 1999, every new patient without clinical evidence of abdominal leakage underwent peritoneal scintigraphy. A total of 59 patients were enrolled in the study. Imaging of the peritoneal cavity was performed by mixing 74 MBq (2 mCi) of 99 m technetium sulfur colloid with 2 L of 1.36% dextrose peritoneal dialysis solution. Sequential gamma camera static images were obtained at 0 minutes, 60 minutes, and after drainage. Ten abdominal hernias (2 diaphragmatic leaks, 8 inguinal hernias) were observed in ten patients (6 males, 4 females; mean age: 65.1 years). One patient with diaphragmatic leak recovered partial renal function and stopped continuous ambulatory peritoneal dialysis (CAPD); the other was switched to automated peritoneal dialysis (APD). Among the eight patients with inguinal hernia, six had no clinical manifestations within eight months of follow-up. Two patients became symptomatic at 15 months and 25 months respectively. They underwent surgical repair. In CAPD patients without obvious abdominal hernias, peritoneal scintigraphy at onset of dialysis discovered 17% positive cases. The technique of scintigraphy is safe, with a low radiation exposure. Surgical repair for maintenance on CAPD is not always necessary, and a change in the PD strategy may be useful.

Adult↗
PubMedDate not supplied

[Myocardial contractile function in acute heart failure during exposure to strophanthin and its combination with alpha-tocopherol].

In experiments on rabbits it was established that strophanthin (0.05 mg/kg) administered to animals with cardiac insufficiency due to a severe overloading of the heart function by occlusion of the diaphragmatic portion of the aorta by 4/5 of its diameter improved the contractile activity and relaxing properties of the left ventricle. This effect is however transient (up to 15-30 minutes) with the subsequent reduction of its characteristic indices, the development of symptoms of intoxication and not infrequently death of animals. alpha-tocopherol administered before the pathology reproduction (10 mg/kg, 3 days) increases the period of myocardial compensation and when given in combination with strophanthin significantly potentiates the cardiac effect of glycoside manifesting by an increase of the strength and rate of contraction and intensity of diastolic relaxation of the myocardium, prolongs the animal's life.

Acute Disease↗
PubMed1976

[Experimental investigations of muscle transplants in correction of congenital diaphragmatic defects (author's transl)].

Rives muscle plasty using a pediculate flap of the latissimus dorsi muscle is an approved method for correction of large congenital diaphragmatic defects. To study morphology and function of the transplanted muscle flap 10 beagle dogs were operated upon bilaterally in two stages. Thus a total of 20 muscle transplants was evaluated. A standard Rives plasty was performed, emg electrodes were inserted into the diaphragm as well as into the muscle transplant. The surgical procedure was tolerated very well, there was no operative mortality. The period of observation varied between 18 and 48 weeks, the average being 30 weeks. Postoperatively there was no electric activity found in the muscle transplants, whereas the diaphragm showed its characteristic interference pattern during inspiration. In 5 cases, however, action potentials appeared in the muscle flap after 12 to 16 weeks. They had the semblance of fibrillation potentials and short sharp waves and were considered to be preceding reinnervation potentials, which occured 24 to 32 weeks postoperatively in these cases. In 2 cases the emg findings were inconstant, in the residual 13 cases there was no electrical activity in the muscle transplant during all the observation time. The emg findings corresponded to the histological postmortem findings. These showed in altogether 6 cases numerous intact muscle fibres as well as nerve trunks with neurites, especially in the neighbourhood of the diaphragm. In the middle of the flap and even more near the thoracic wall the number of intact muscle fibres decreased. Thus a partial reinnervation due to muscular neurotization starting from the diaphragmatic margin was assumed in these cases. In the rest of the flaps the muscles were largely atrophic and showed considerable lipomatosis, only minor fibrosis and never a distinct scar formation. Therefore, the flaps represented living tissue with intact vascularization and functionally good adaptability. Reinnervation, observed in some cases, is not the main factor for the good clinical results obtained with Rives muscle plasty, but can improve adaptability and elasticity of the transplant considerably. According to the lack of scar formation and the preponderance of fatty tissue an increase of the transplant considerably. According to the lack of scar formation and the preponderance of fatty tissue an increase of the transplants size during growth seems possible. Thus Rives muscle plasty using a flap of the latissimus dorsi muscle to cover large congenital diaphragmatic defects seems morphologically as well as functionally superior to other procedures especially those using plastic material.

Animals↗
PubMed2004

[Surgery for diaphragmatic palsy].

Diaphragmatic palsy leads to a permanent ascension of one or both hemi-diaphragms with highly variable functional impact. The underlying mechanisms can be divided into two main categories: neurological or muscular disorder leading to peripheral dysfunction; defective or non-transmitted central command causing central dysfunction. A complete morphological and functional work-up is required to determine the circumstances leading to diaphragmatic palsy and the uni- or bilateral nature of the paralysis. The entire phreno-diaphragmatic transmission chain from the cranium to the diaphragmatic muscle must be analyzed to search for a local cause. Function tests are used to examine central command and transmission, function of the phrenic nerve, and the capacity of the diaphragmatic muscle to generate sufficient pressure for efficacious ventilation. Once indirect causes of diaphragmatic ascension (independent of the phreno-diaphragmatic system) have been ruled out, surgery may be proposed for symptomatic, permanent and irreversible diaphragmatic paralysis. A tension procedure may be sufficient in the event of eventration with or without phrenic palsy. For well-selected patients with central paralysis due to supraspinal lesions with intact nerves and muscles, implantation of a phrenic pacemaker may be helpful to eliminate positive pressure mechanical ventilation and restore more physiological respiration.

Diaphragm↗
PubMed2001

Abnormal esophageal anatomy associated with a congenital diaphragmatic hernia: report of a case.

Gastroesophageal reflux associated with anatomic and functional abnormalities of the esophagus may be encountered following the repair of a congenital diaphragmatic hernia (CDH). We report herein the case of a newborn male infant with CDH found to have an air-filled paravertebral structure. Upper gastrointestinal series confirmed the presence of an ectatic esophagus with poor peristalsis and severe gastroesophageal reflux. The patient required jejunostomy after a safe period of total parenteral nutrition. He tolerated oral feeding following medical treatment without the need for antireflux surgery. The association of dysphagia, esophageal ectasia, and gastroesophageal reflux is rarely seen with CDH, and feeding intolerance is a self-limited disorder that does not usually necessitate antireflux surgery.

Deglutition Disorders↗
PubMed2001

[Congenital diaphragmatic hernia in a polytrauma patient].

A case of congenital, bilateral, diaphragmatic hernia in a patient with multiple trauma after a motor accident is presented. No anamnestic information was available because of the need for intubation at the accident site. After the insertion of bilateral chest tubes because of left sided pneumothorax and right sided haematopneumothorax a mediastinal mass became apparent. A CT scan revealed a bilateral diaphragmatic hernia. Problems and therapy of this condition as well as differentiation between congenital and traumatic hernias are discussed in this case report. A mediastinal mass of unknown origin in multiple trauma patients suggests the presence of traumatic diaphragmatic hernia. Diagnostic signs suggesting congenital hernia as compared to acute traumatic hernia are: unilateral or bilateral localisation in the dorsal muscular part of the diaphragm and non-suspicious appearance of parenchymal abdominal organs in relation to the size of the hernia. Diaphragmatic hernias reduce the vital and functional residual capacity of the lungs, possibly leading to respiratory complications and infections.

Aged↗
PubMed2001

Structural immaturity of the heart in congenital diaphragmatic hernia in rats.

PURPOSE: The form and function of the heart are the final result of an integration of cells, tissues, and extracellular material. The extracellular matrix (ECM) is a complex array of different molecular components, and it plays an important role for the transfer of mechanical force in both contraction and relaxation phases in the cardiac cycle. ECM plays also a significant role in the development of the heart. The aim of this study was to evaluate the expression of important ECM components in the heart of rats with induced CDH to test the hypothesis that an alteration of ECM may contribute to the cardiac maldevelopment, which recently has been identified as a contributive factor for the high mortality rate in babies with congenital diaphragmatic hernia (CDH). METHODS: CDH model was induced in pregnant rats after administration of 100 mg of nitrofen on day 9.5 of gestation (term, 22 days). In control animals the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The fetuses were divided into 2 groups: normal control (n = 10) and nitrofen-induced CDH (n = 10). Reverse transcription polymerase chain reaction (RT-PCR) was performed to evaluate the relative amount of tropoelastin and alpha1 (I) procollagen mRNA expression. Elastin protein content was measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: There was a reduction in tropoelastin mRNA (P <.05) and procollagen mRNA (P <.05) in CDH compared with controls. The cardiac alpha-elastin content also was reduced in CDH (P <.01). CONCLUSIONS: The reduced cardiac tropoelastin and procollagen gene expression and the reduced alpha-elastin content indicate that the heart in CDH structurally is immature. The reduced production of cardiac ECM may contribute to a contractile dysfunction, which makes the heart unable to respond to the hemodynamic load accompanying persistent pulmonary hypertension (PPH).

Abnormalities, Multiple↗
PubMed2006

Treatment of a case with right-sided diaphragmatic hernia associated with an abnormal vessel communication between a herniated liver and the right lung.

We herein report a rare case of a newborn girl with a right-sided congenital diaphragmatic hernia where a herniated liver had an abnormal vessel communication with the right lung. A surgical repair was initially attempted through a thoracic approach at 4 days of age where only a plication of the hernia capsule was performed without a prominent improvement in the respiratory condition. At 1 year of age, an angiographic examination was performed, which revealed pulmonary hypertension and abnormal vessel communications where the right pulmonary flow returned to the herniated liver and the right lung also received an arterial supply from the liver. During the second surgical repair performed at 1 year and 1 month of age, an abdominal approach through a right subcostal incision was selected. The aberrant vessels between the lung and the liver were carefully identified and ligated. Because the right lobe of the liver was completely herniated, a hepatic segmentectomy of S6 and S7 was performed. The patient has been doing well for 21 months without any mechanical ventilation since 2 months after undergoing the radical second operation. When performing surgery on a right-sided diaphragmatic hernia, the potential presence of such a vessel anomaly should be carefully taken into consideration.

Female↗