PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Diaphragmatic function”

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

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

At least 991 records · Page 55Linked to original sources
PubMed1997

Congenital diaphragmatic hernia--a tale of two cities: the Toronto experience.

PURPOSE: The optimal therapy for congenital diaphragmatic hernia (CDH) is evolving. This study analyzes the results of treatment of CDH in a large tertiary care pediatric center using conventional and high-frequency oscillatory ventilation (HFOV) without extracorporeal membrane oxygenation (ECMO) contrasting these with a parallel study from a similar large urban center using conventional ventilation with ECMO. METHODS: Between 1981 and 1994, 223 consecutive neonates who had CDH diagnosed in the first 12 hours of life were referred for treatment before repair. Conventional ventilation was used with conversion to HFOV for refractory hypoxemia or hypercapnia, and a predicted near 100% mortality rate. ECMO was used in only three patients, all of whom died. A retrospective database was collected. Thirty-one clinical variables were tested for their association with the outcome. Common ventilatory and oxygenation indices were tested for their prognostic capability. RESULTS: Apgar scores, birth weight, right-sided defects, pneumothorax, total ventilatory time, and the use of high frequency oscillatory ventilation were the only variables associated with outcome. A modified ventilatory index and postductal A-aDo2 were strong prognostic indicators. From 1981 to 1984 surgery was performed on an emergency basis. Since 1985 surgery was deferred until stabilization had been achieved. This resulted in a shift in the mortality from postoperative to preoperative with no change in total survival. HFOV did not alter the overall survival. Results of autopsies performed (70%) showed significant pulmonary hypoplasia and barotrauma as the primary causes of death. The survival was 54.7%. CONCLUSION: Conventional ventilation with HFOV produced equal survival to conventional ventilation with ECMO in two comparable series. Pulmonary hypoplasia was the principle cause of death. This continued high mortality at both centers suggests that new therapies are required to improve outcomes.

Extracorporeal Membrane Oxygenation↗
PubMed2006

Fetal magnetic resonance imaging.

PURPOSE OF REVIEW: Fetal magnetic resonance imaging is becoming more used in the evaluation of complex fetal abnormalities. Rapid advances in the technology and application of fetal magnetic resonance imaging necessitate a review of this subject. RECENT FINDINGS: Diffusion-weighted imaging, magnetic resonance spectroscopy and functional magnetic resonance imaging may allow assessment of fetal brain even before anatomical abnormalities are demonstrated. We discuss the uses of fetal magnetic resonance imaging in better assessment of pulmonary hypoplasia, congenital diaphragmatic hernia and renal anomalies. SUMMARY: The additional information from fetal magnetic resonance imaging, beyond that obtained by ultrasound, is invaluable in prenatal counseling, delivery planning and planning for pre- or postnatal intervention. As intrauterine and neonatal surgery evolve, so will the utilization of fetal magnetic resonance imaging.

Abdomen↗
PubMed1998

Congenital diaphragmatic hernia: mortality determinants in a Hispanic population.

OBJECTIVES: Determine which factors were associated with mortality in our patients, specifically whether ventilatory parameters and arterial blood gas could be used to predict outcome. The role of delaying surgery and the presence of contra lateral pneumothorax were also assessed. BACKGROUND: Mortality among babies born with congenital diaphragmatic hernia remains high. The associated pulmonary hypoplasia and hypertension account for most of the overall mortality. There is no uniform consensus as to which parameters predict outcome. METHOD: Study population consisted of thirty-two patients with CDH managed during a ten-year period. Retrospective data obtained included: perinatal data, postnatal complications, ventilatory parameter data, arterial blood gas, type and age of surgery. Ventilatory index, oxygenation index and arterial to alveolar oxygen difference (A-aDO2) within the first 24 hours of life and after surgical correction were compared among the 23 patients who underwent surgical correction. Timing of surgery and frequency of pneumothorax were compared between survivors and non-survivors. Epi-Info Software Package was used for statistic analysis. RESULTS: Overall survival was 40%. Survival of surgically corrected infants was 61%. Non-survivors had significantly higher A-aDO2 than survivors (p < 0.05). No significant differences in pCO2, ventilatory index, or oxygenation index were identified between survivors and non survivors. Surgical repair performed after the first twenty-four hours of life, was associated with a higher survival rate (p < 0.05). Fourteen patients (39%) developed contralateral pneumothorax, eleven (79%) of these died. CONCLUSIONS: (1) contralateral pneumothorax was associated with higher mortality, 2) A-aDO2 was a better prognostic indicator than pCO2, ventilatory index, or oxygenation index, 3) delaying surgical repair was associated with better survival rate.

Age Factors↗
PubMed2003

A pattern recognition method to distinguish gradual unilateral diaphragm paralysis in the cat.

This work deals with the application of a pattern recognition method to distinguish the degree of diaphragm paralysis after gradual unilateral sections of phrenic nerve rootlets in anesthetized, spontaneously breathing cats. The data set consisted of the features that characterize breathing pattern and of phrenic nerve amplitude. The method called for stratification of 6-dimensional vectors into three classes: intact, partial, and complete unilateral phrenicotomy, which offers the possibility to construe the classification rule on the basis of the information contained in a set of feature vectors with the known class-membership. This method deals with the use of a distance function as a measure of similarity between two feature points. The results show that the degree of diaphragm paralysis could be recognized with the probability higher than 90%. Distinguishing the severity of diaphragmatic dysfunction and the compensatory strategies of the respiratory system, knowing only a handful of basic values describing breathing pattern, might have a practical meaning in respiratory emergencies.

Animals↗
PubMed1991

[Changes in the peritoneum of the small intestine and diaphragm in experimental portal hypertension].

Diaphragm and small intestine peritoneum morphology was studied in experimental portal hypertension in rats with the help of luminescent, transmission and scanning electron microscopy techniques. Structural organizations of these peritoneum portions and performance function were different: fluid transudation realized through the small intestine peritoneum and resorption occurred via diaphragm peritoneum. Morphological signs allowed to judge about the increasing of fluid transudation in abdominal cavity and diaphragmatic resorption in early period of portal hypertension. Morphological alterations appeared in peritoneum resorption sites (pumping diaphragmatic hatchs) according to progress of portal hypertension that indicated decompensation process of peritoneal fluid absorption and led to ascites.

Animals↗
PubMed1979

[Use of a membrane oxygenator for correcting acute, experimental respiratory insufficiency].

A model of acute respiratory insufficiency ARI was created in the experiments on 16 dogs by means of a valvular device furnishing a free inhalation and a limited expiration. The diaphragmatic oxigenator devised in VNIIP with an armoured diaphragm of "Sigma"--type was switched on at the height of ARI. 3 hours' perfusion corrected successfully the manifestation of hypercapnic hypoxia. The pulmonary function restored after the experiment.

Acute Disease↗
PubMed2004

Phrenic rehabilitation and diaphragm recovery after cervical injury and transplantation of olfactory ensheathing cells.

Functional respiratory recovery was evaluated by recording diaphragm and phrenic nerve activity several months after cervical cord hemisection followed by olfactory ensheathing cell (OEC) transplantation. The intact side was taken as a control in each rat. Sham-transplanted rats did not recover respiratory activity from the ipsilateral lesioned side. By contrast, ipsilateral phrenic and diaphragmatic activities recovered in transplanted rats amounted to 80.7% and 73% of their controls, respectively. After contralateral acute C1 section eliminating any contralateral influence from crossed compensatory pathways, the ipsilateral phrenic activity remained at 57.5% of the control, indicating that the phrenic recovery originated from the ipsilateral side. Supralesional stimulation in these rats elicited sublesional ipsilateral postsynaptic phrenic responses showing that transplantation helped ipsilateral fibers to again transmit nervous messages to the phrenic target, leading to substantial functional recovery. The origin of mechanisms involved in respiratory recovery (regeneration, resurrection, sprouting, sparing, demasking of latent pathways) is discussed.

Animals↗
PubMed1994

New approach to assess quality of life in neonatal surgical cases: medical providers' subjective assessment of disease- and condition-related factors, using the linear analogue scale.

A new questionnaire survey of pediatric surgeons and nurses, using the linear analogue scale, was used to determine subjective assessments of patients' quality of life (QOL) with regard to neonatal surgical diseases and conditions, including those involving anal and urinary functions. The results were analyzed according to the medical providers' years of professional experience. For six neonatal surgical diseases, QOL was assessed more favorably by less experienced surgeons and nurses. The result was similar for adulthood diseases. The development of medical technology can be attributed to this trend; however, QOL for patients with diaphragmatic hernia was assessed less favorably by less experienced surgeons (as 66.1%) than by more experienced surgeons (as 81.6%). Current technology has enabled the survival of neonatal surgical patients who are born prematurely and/or who have serious diseases or anomalies. Consequently this leads to poorer assessment of the surviving patients' QOL. QOL for patients with imperforate anus and spina bifida remained less favorably assessed. That of patients with conditions related to anal and urinary dysfunctions also scaled in the same manner. Anal dysfunction was less favorably assessed by less experienced surgeons (as 40.0%) than by more experienced surgeons (as 49.4%). In part, this discrepancy could be attributed to (1) better adjustment by the patients to their condition over time, and (2) greater focus on QOL issues in recent years. With regard to anal function, low QOL assessment correlated strongly with imperforate anus, Hirshsprung's disease, and spina bifida (P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Prenatal diagnosis and therapeutic intervention].

Experience in fetal invasive therapeutic procedures is currently nearly entirely based on animal experimental research. Structural defects in the human fetus which are potentially amenable to intrauterine surgical treatment are obstructive uropathy, hydrocephaly and diaphragmatic hernia. The results from closed procedures such as shunting of urine or CNS fluid to the amniotic fluid compartment under ultrasound monitoring is as yet not very encouraging. This is partly determined by technical inadequacies, and partly due to insufficient information available on the possible presence of associated anomalies and functional aspects of the affected organ systems. The risks of invasive procedures for the mother and in particular the fetus must be weighed up against the advantages for the fetus if surgery has been successful. It seems that the development of open surgical procedures will determine the future of fetal surgery.

Drainage↗
PubMed1994

The effects of biofeedback assisted breathing retraining on lung functions in patients with cystic fibrosis.

This study examines the effects of respiratory muscle feedback and breathing retraining (BRT) on lung function in patients with cystic fibrosis (CF). Twenty-six patients with CF were matched for age and severity of disease. Standard respiratory spirometry was performed on all subjects before and after biofeedback training. Thirteen experimental subjects underwent eight sessions of pneumographic or strain-gauge feedback from the abdominal muscles and electromyogram feedback from accessory respiratory muscles to assist in learning diaphragmatic and pursed-lips breathing maneuvers. Control subjects received biofeedback-assisted (hand warming) relaxation training. Results revealed a significant improvement in FEV1 and mean forced expiratory flow during the middle half of forced vital capacity (FVC) for the biofeedback group, while the control group showed no change. A similar trend was noted for FVC. These data suggest that respiratory muscle feedback and BRT may improve lung function in patients with CF.

Abdominal Muscles↗
PubMed1978

Upper airway function during sleep and wakefulness: experimental studies on normal and anesthetized cats.

Normal (N = 6) and anesthetized (N = 70) cats were used to study the laryngeal abductors, the posterior cricoarytenoid (PCA) muscles, during sleep and wakefulness and to investigate sites within the brainstem that influenced PCA and diaphragmatic activity. The findings were as follows: 1. During wakefulness, PCA activity occurred throughout the respiratory cycle but was most intense during inspiration. Both expiratory and inspiratory PCA activity declined during sleep--the former more so than the latter. The decline in abductor activity was maximal in REM sleep. 2. Barbiturate anesthesia, according to the dosage, produced PCA activity patterns characteristic of either wakefulness or sleep. 3. The brainstem between A4 and P14 was mapped with stimulating electrodes. Rostral brainstem sites showed predominantly facilitatory effects of PCA activity; caudal sites produced predominantly blocking effects. 4. PCA facilitation consisted of (a) an increase in the duration of the PCA burst, (b) and increase in the discharge frequency of the PCA motor units, and (c) a recruitment of larger motor units. PCA blocking effects were the opposite, i.e., burst durations were shortened and motor units were decruited. 5. Facilitatory sites produced clear change in intensity and duration of PCA activity at stimulation intensities below those necessary to obtain changes in the intensity of diaphragmatic activity. 6. Stimulation of facilitatory sites during expiration caused phase switching to inspiration. In some cases, stimulation during inspiration caused phase switching to expiration. The results are discussed in terms of their implications for the obstructive apneas of sleep and in terms of the neural control of breathing.

Airway Resistance↗
PubMed1997

Distribution of lymphatic stomata on the pleural surface of the thoracic cavity and the surface topography of the pleural mesothelium in the golden hamster.

BACKGROUND: The distribution of lymphatic stomata that open to the pleural cavity is unclear. The distribution and the surface topography of the pleural and visceral pleurae are key factors in the turnover of pleural fluid and respiration physiology. METHODS: Nine golden hamsters (Mesocricetus auratus) from 26 to 33 weeks of age were used for the study. The gross anatomy of the thorax and the arterial supply to the lung were studied in four hamsters. Five thoracic hemispheres, three diaphragms, and tissue blocks of the heart and lung were prepared from the remaining five hamsters. The thoracic hemispheres were fixed in 2.5% glutaraldehyde and the muscular bands at each intercostal space were carefully cut along the costae. The intercostal bands were processed for scanning electron microscopy (SEM) and the localization and the number of lymphatic stomata were recorded. The diaphragms and blocks of the lung and heart were also processed for SEM and the surface topography was observed. RESULTS: The right and left superior lobes of the lung were supplied by the bronchial artery that originated from the right costocervical trunk and left internal thoracic artery, respectively. Lymphatic stomata and mesothelial discontinuities (pores and gaps) were predominantly located in areas lined with cuboidal cells. The areas of cuboidal cells occupied approximately 4.6 mm2, namely, 1% of the total area of the thoracic hemisphere. There were about 1,000 lymphatic stomata per thoracic hemisphere. About 15% of lymphatic stomata were distributed in the ventro-cranial regions of the thoracic wall, with about 85% in the dorsocaudal region. In the former region, lymphatic stomata were found along the costal margins. In the latter, they were predominantly located in the pre- and paravertebral fatty tissue. There were also areas of cuboidal cells on the pleural surface of the diaphragm. Some mesothelial pores and gaps were found, but no lymphatic stomata opened on the pleural surface of the diaphragm. The pleural surface of the lung and that of the heart were lined with flattened polygonal cells. The topography of the surface varied, but there were no mesothelial discontinuities of the type commonly found in the parietal pleura. CONCLUSIONS: 1) The parietal pleura has a surface structure that is more permeable and absorptive for fluid and particulate matter than the visceral pleura. 2) The distribution of lymphatic stomata does not correspond directly to the pleural liquid pressures that have been reported. 3) The functions of lymphatic stomata should be considered not only in terms of fluid turnover but also in terms of self-defense mechanisms. 4) The presence or absence of lymphatic stomata on the diaphragmatic pleura should be re-examined and determined in a variety of animal species.

Animals↗
PubMed2000

Fetal surgical intervention.

Despite advances in perinatal management, some congenital disorders continue to have significant morbidity and mortality both in utero and in the early postnatal period. In selected anomalies, fetal surgical intervention can alter the natural history of the disorder, leading to improved survival rates and functional outcomes. While therapies are primarily aimed at life-threatening disorders, some significantly morbid disorders may also be addressed prenatally. Potential indications for fetal surgery include mass lesions causing hydrops fetalis, congenital diaphragmatic hernia, myelomeningocele, urinary obstruction and disorders of twins. A thorough prenatal evaluation and extensive family counseling are necessary prior to intervention. Improvements in minimally invasive techniques may minimize the greatest challenge of fetal surgery, management of postoperative preterm labor.

Female↗
PubMed1985

Regional protein absorption rates from the pleural cavity in dogs.

In five supine spontaneously breathing anesthetized dogs we injected into the pleural space 0.5-1 ml of saline solution containing 2 mg/ml albumin labeled with technetium-99m. By use of a gamma camera placed horizontally over the chest, we followed, up to 120 min, the activity over the whole lung and over the preferential accumulation areas of the label (regions of interest, ROI) that corresponded to the apical, mediastinal, and laterodiaphragmatic regions. Activities were corrected for the decay rate of the isotope used. On the average, the activity over the whole lung decreased by 27% up to 120 min. The overall activity over the ROI amounted to 44.3% after the injection and decreased to 24% of total at 120 min, thus accounting for 75% of the total decrease in activity. At 10 min, the activity per unit surface of the gamma camera image (As) was from 2.2- to 5.7-fold higher over the ROI than for the rest of the lung image. The decrease of As at 120 min was 18-, 13-, and 5-fold greater for mediastinal, diaphragmatic, and apical regions, respectively, compared with the rest of the lung image. The time course of the changes in As are discussed in terms of regional albumin egress rate based on the functional interaction between the Starling and the lymphatic mechanisms.

Absorption↗
PubMed1988

Regulation of end-expiratory lung volume during exercise.

We determined the effects of exercise on active expiration and end-expiratory lung volume (EELV) during steady-state exercise in 13 healthy subjects. We also addressed the questions of what affects active expiration during exercise. Exercise effects on EELV were determined by a He-dilution technique and verified by changes in end-expiratory esophageal pressure. We also used abdominal pressure-volume loops to determine active expiration. EELV was reduced with increasing exercise intensity. EELV was reduced significantly during even mild steady-state exercise and during heavy exercise decreased an average of 0.71 +/- 0.3 liter. Dynamic lung compliance was reduced 30-50%; EELV remained greater than closing volume. Changing the resistance to airflow (via SF6-O2 or He-O2 breathing) during steady-state exercise changed the peak gastric and esophageal pressure generation during expiration but did not alter EELV; breathing through the mouthpiece produced similar effects during exercise. EELV was significantly reduced in the supine position. With supine exercise active expiration was not elicited, and EELV remained the same as in supine rest. With CO2-driven hyperpnea (7-70 l/min), EELV remained unchanged from resting levels, whereas during exercise, at similar minute ventilation (VE) values EELV was consistently decreased. At the same VE, treadmill running caused an increase in tonic gastric pressure and greater reductions in EELV than either walking or cycling. We conclude that both the exercise stimulus and the resultant hyperpnea stimulate active expiration and a reduced FRC. This new EELV is preserved in the face of moderate changes in mechanical time constants of the lung. This reduced EELV during exercise aids inspiration by optimizing diaphragmatic length and permitting elastic recoil of the chest wall.

Adult↗
PubMed1988

Low-frequency diaphragmatic fatigue in spontaneously breathing humans.

We used transdiaphragmatic peak twitch tension (PTT) elicited by bilateral phrenic nerve stimulation to ascertain whether low-frequency (LF) diaphragmatic fatigue (DF) can be induced in spontaneously breathing humans by a combination of an inspiratory resistive load (IRL) and graded treadmill exercise (GXT). Our subjects were 10 young males with normal cardiopulmonary function. Before exercise we measured PTT in each subject by administering supramaximal electrical pulses of 100-microseconds duration at a frequency of 1 Hz to each phrenic nerve with the subjects breath holding at functional residual capacity at a given thoracoabdominal configuration. A minimum of six satisfactory PTT measurements were made in each subject, and we computed the 95% confidence limits (CL) for each subject. The subjects then inspired through a resistive load of 38 cmH2O.1(-1).s-1 while carrying out the GXT until exhaustion. After the GXT, PTT was remeasured in all subjects. In five of the subjects, the post-GXT mean PTT fell below the 95% CL of the pre-GXT mean PTT. However, post-GXT PTT means for the other five subjects were within the 95% CL of the pre-GXT means. In conclusion, using PTT as a measure of LFDF, these results demonstrate that LFDF can be produced in 50% of spontaneously breathing young normal males.

Adult↗
PubMed1985

Results of diaphragmatic plication for unilateral diaphragmatic paralysis.

Seven adult patients with dyspnea resulting from nonmalignant unilateral diaphragmatic paralysis underwent plication of the affected hemidiaphragm. Preoperatively, the patients complained of exertional dyspnea and orthopnea and had a reduced arterial oxygen tension, total lung capacity, vital capacity, expiratory reserve volume, and functional residual capacity. Plication was performed by imbricating the diaphragm in layers through a thoracotomy. After plication there was a significant increase in arterial oxygen tension and all lung volumes except residual volume. The patients' symptoms were improved with plication and a significant decrease was recorded in breathlessness on a visual analogue scale. There were no postoperative complications and mean hospital stay was 12 days.

Adult↗