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PubMed1980

Determinants of hypoventilation during wakefulness and sleep in diaphragmatic paralysis.

A 45-yr-old man with limb girdle muscular dystrophy, bilateral diaphragmatic paralysis, chronic carbon dioxide retention, and hypersomnolence was studied to determine the causes of hypoventilation during wakefulness and during sleep. Awake hypoventilation was associated with an insufficient inspiratory effort in the presence of inefficient respiratory muscles and a shortened inspiratory time. During sleep, severe hypoventilation and oxygen desaturation occurred only during REM-induced intercostal and accessory muscle inhibition.

Diaphragm↗

PubMed1996

Transmyocardial laser revascularization: clinical experience with twelve-month follow-up.

We are investigating a new technique for myocardial revascularization in which an 800 W carbon dioxide laser is used to drill 1 mm diameter channels into a beating heart after left thoracotomy. Clotting occludes the channels on the subepicardium, and in the long-term setting, blood from the left ventricular cavity flows through these channels to perfuse the ischemic subendocardium. To test the efficacy of this technique in a preliminary clinical trial, we used it as sole therapy for 21 consecutive patients. All patients had hibernating myocardium, reduced coronary flow reserve, or both, had distal diffuse coronary artery disease, and had angina refractory to normal therapy. Eight patients were excluded from follow-up because of death (n=5), rerevascularization (n=2), or diaphragmatic paralysis resulting in postoperative respiratory incapacity (n=1). In the remaining 13 patients available for follow-up, the mean angina class (Canadian Cardiovascular Society) was 3.7 +/- 0.4 before operation and 1.8 +/- 0.6 12 months after operation (p < 0.01). Mean resting left ventricular ejection fraction was 48% +/- 10% before operation and 50% +/- 8% at 12-month follow-up. At 12 months, resting mean subendocardial/subepicardial perfusion ratio had increased by 20% +/- 9% in septal regions treated by laser but decreased by 2% +/- 5% in untreated regions (n=11, p <.001). These results suggest that revascularization by this laser technique positively affects subregional myocardial perfusion and may result in clinical benefits for patients with reversible myocardial ischemia. Studies to date have not demonstrated significant changes in global and regional ventricular contractile function.

Aged↗

PubMed1981

Hypercapnic stimulation of respiratory activity in unanesthetized fetal sheep in utero.

Respiratory responses to hypercapnia were studied in seven chronic in utero fetal lambs between 105 and 138 days' gestation (16 expts). Fetal arterial CO2 tension was raised (mean increase 9.9 Torr) by altering maternal inspired gas concentrations. Diaphragmatic electromyogram (EMG) was recorded as the index of respiratory activity. Electrocortical and electroocular activity (3 fetuses) were monitored in an attempt to define sleep state. Average respiratory rate increased (90%) and fetal apnea decreased (60%) during hypercapnia. Mean respiratory rate during "on" periods (greater than 6 EMG bursts/min) increased significantly during hypercapnia throughout the gestational epoch studied. Mean duration of the inspiratory time (TI) showed no significant change. Variability in both rate and TI decreased in response to CO2 at all gestations. Integrated EMG activity per burst divided by TI increased significantly at all gestations; however, no gestational increase in responsiveness to CO2 was seen. Sleep states were not able to be consistently identified, and a quantifiable electrocortical response to CO2 was not observed. These results indicate a relatively early functional maturation of fetal respiratory responses to CO2.

Animals↗

PubMed1998

Subtotal duodenectomy with jejunal patch for megaduodenum secondary to congenital duodenal malformation.

BACKGROUND/PURPOSE: This report describes a technique devised for two children with megaduodenum consisting of subtotal duodenal resection with the proximal jejunum used as an onlay patch. METHODS: A 2-year-old boy presented after unsuccessful surgical repairs for duodenal stenosis with web. Another 8-year-old boy returned from the United States after several surgical procedures for complicated congenital left diaphragmatic hernia with gastric outlet obstruction. Both boys manifested postprandial right upper abdominal fullness, occasional vomiting, abdominal pain, and failure to thrive. Upper gastrointestinal contrast study findings showed massively dilated duodenums in both patients that were larger than the stomach. During the operative procedures, about 95% of the duodenal wall was resected, leaving the basal portion that was unified with the pancreatic head and the ampulla of Vater as linguiform flap, which was covered with the proximal jejunum as an onlay patch so as to form the anterior wall of the duodenal bulb. RESULTS: The patients showed markedly improved quality of life and catch-up growth after the operations. The duodenal bulbs were of adequate size in follow-up gastrointestinal series. CONCLUSION: This technique will be useful in cases of functional duodenal obstruction with megaduodenum secondary to congenital duodenal malformations leading to blind loop syndrome.

Child↗

PubMed1996

The AAPM/RSNA physics tutorial for residents. Physics of SPECT.

Single-photon emission computed tomography (SPECT) provides three-dimensional (3D) image information about the distribution of a radiopharmaceutical injected into the patient for diagnostic purposes. By combining conventional scintigraphic and computed tomographic methods, SPECT images present 3D functional information about the patient in more detail and higher contrast than found in planar scintigrams. A typical SPECT system consists of one or more scintillation cameras that acquire multiple two-dimensional planar projection images around the patient. The projection data are reconstructed into 3D images. The collimator of the scintillation camera has substantial effects on the spatial resolution and detection efficiency of the SPECT system. Physical factors such as photon attenuation and scatter affect the quantitative accuracy and quality of SPECT images, and various methods have been developed to compensate for these image-degrading effects. In myocardial SPECT, an important application of SPECT, recent use of attenuation compensation methods has provided images with reduced artifacts and distortions caused by the non-uniform attenuation in the chest region and by the diaphragmatic and breast attenuation. Attenuation-compensated myocardial SPECT images have the potential to improve clinical diagnosis by reducing the false-positive and false-negative detection of myocardial defects. In the future, further improvement in SPECT images will be realized from the continuous development of new radio-pharmaceuticals for new clinical applications, instrumentation with high spatial resolution and detection efficiency, and image reconstruction algorithms and compensation methods that reduce the image-degrading effects of the collimator-detector, attenuation, and scatter.

Humans↗

PubMed1994

Anesthesia and chest wall function in dogs.

Three anesthetics (pentobarbital, halothane, and isoflurane) were studied in six mongrel dogs to systematically compare their effects on chest wall function during spontaneous breathing. Each dog received each anesthetic on separate occasions. Electrical activities of several respiratory muscles were measured with chronically implanted electrodes, and chest wall motion was assessed by high-speed three-dimensional computed tomography scanning. Phasic expiratory muscle activity was markedly depressed by volatile anesthetics halothane and isoflurane compared with pentobarbital. In contrast, inspiratory activity in parasternal intercostal muscles was relatively well preserved during anesthesia with these volatile agents. The contribution of expiratory muscles to tidal volume was diminished during halothane and isoflurane compared with pentobarbital anesthesia. As anesthesia was deepened, expiratory muscle activity was unchanged during pentobarbital anesthesia, enhanced in some dogs during isoflurane anesthesia, and remained absent during halothane anesthesia. Activity in parasternal intercostal muscle was depressed as inspired concentration of halothane or isoflurane was increased, whereas diaphragmatic activity was unchanged. Depression of expiratory muscle activity by halothane persisted when breathing was stimulated by positive end-expiratory pressure, with significant mechanical consequences for chest wall configuration. Many of these findings are in contrast with previous observations in humans and suggest that the dog is not a suitable model for the study of the effects of anesthetic drugs on the pattern of human respiratory muscle activity.

Abdominal Muscles↗

PubMed1991

[Effects of diaphragm plication for phrenic nerve paralysis on respiratory mechanics and diaphragm function].

The purpose of this study is to examine the effects of unilateral diaphragm plication for phrenic nerve paralysis on the respiratory mechanics and diaphragm function. Study 1: We performed thoracotomy (BASELINE), left phrenicotomy (INJURY) and left diaphragm plication (PLICATION) in ten dogs. After chest was closed in each condition, measured were the tidal volume (TV), respiratory rate (f), esophageal and gastric pressure swing (delta Pes, delta Pga), dynamic compliance (Cdyn) the ratio of gastric to esophageal pressure swing (delta Pga/delta Pes) and the work of breathing per liter (WOB/L) under stable spontaneous breathing. Study 2: In eight other left-phrenicotomized dogs, Pdi and fractional shortening of the costal diaphragm during contralateral electrophrenic stimulation were measured before and after plication. After plication TV, delta Pga/delta Pes, Cdyn, Pdi and fractional shortening during stimulation increased significantly, whereas Pes and WOB/L decreased significantly compared with INJURY condition. In conclusion unilateral diaphragm plication after paralysis improves the intact hemidiaphragm contractility and diaphragmatic contribution to breathing.

Animals↗

PubMedDate not supplied

Typology of the respiratory muscles in normal men and in patients with moderate chronic respiratory diseases.

Histochemical muscle fibre composition was studied in biopsies from the diaphragm, the external and internal intercostal muscles in the fifth intercostal space and horizontal and vertical parts of the serratus in 8 subjects with normal lung function and in 18 patients with abnormal lung function (6 restrictive and 12 obstructive). Muscle fibres were classified as type I (slow twitch) or type II (fast twitch) on the basis of their myofibrillar ATPase pH lability. All the muscles studied showed a mosaic pattern with the two fibre types. In every respiratory muscle, the percentage of type I fibres was higher than 50%. There was no significant difference between the three groups (normal, restrictive and obstructive) for each of the six muscles studied. The fibre diameters were similar for all types and muscles (range of means: 41-63 micron), except for the diaphragm in which the diameters of type I and type II fibres were significantly higher in the normal subjects as compared to the obstructive and restrictive patients. Moreover, there was a significant linear correlation between the diameter of the diaphragmatic fibres and vital capacity and FEV1. A low "atrophy factor" was found for each muscle studied with a large intra-individual variation. The results support the idea that the increased respiratory loading due to disease do not hypertrophy the respiratory muscles and suggest that the effect of the disease on the respiratory muscles is more related to the increased mechanical impedance of the respiratory system rather than to the changes in thoracic configuration.

Adenosine Triphosphatases↗

PubMed1988

Diaphragmatic relaxation rate after voluntary contractions and uni- and bilateral phrenic stimulation.

We compared the rate of relaxation of the diaphragm (RRdi) after unilateral phrenic nerve stimulation, bilateral phrenic nerve stimulations, and short sharp voluntary contractions (sniffs). RRdi was measured as the maximum rate of decline in transdiaphragmatic pressure (Pdi) corrected for the change in Pdi [maximum relaxation rate (MRR)/delta Pdi], the time constant (tau) of the later exponential decline in Pdi, and the time to half relaxation (1/2 RT). In five subjects there was no difference in mean RRdi apart from a smaller MRR/delta Pdi (P less than 0.05) for left unilateral compared with either right unilateral or bilateral needle stimulation. However, RRdi varied unpredictably between unilateral and bilateral stimulation of the phrenic nerve in individual subjects. In the same five subjects, sniffs were found to have a slower RRdi than bilateral stimulations (MRR/delta Pdi 0.0064 +/- 0.0007 vs. 0.0074 +/- 0.0018/ms, tau 57.2 +/- 8.7 vs. 48.2 +/- 7.4 ms, 1/2 RT 108.9 +/- 10.9 vs. 73.9 +/- 6.0 ms; all P less than 0.05). The application and inflation of an abdominal binder to an external pressure of 60 mmHg resulted in a decrease in functional residual capacity (-710 +/- 70 ml), but there was no effect on relaxation parameters. Our findings suggest that in the evaluation of RRdi 1) unilateral hemidiaphragmatic stimulations may not accurately reflect the in vivo contractile properties of the diaphragm, 2) sniff maneuvers are not voluntary equivalents of phrenic nerve stimulations, and 3) RRdi is not affected by abdominal binder inflation up to 60 mmHg.

Adult↗

PubMed1998

[Extracorporeal membrane oxygenation in neonatology: review of the use of the method].

Extracorporeal life support and extracorporeal membrane oxygenation characterize the use of mechanical devices for temporary support of heart and lung function. The mechanical circuit consists of a blood pump (heart), membrane oxygenator (lung: which accomplishes both carbon dioxide removal and oxygen delivery), heat exchanger and a servo-control module. Venous blood is drained from the right atrium through the right internal jugular vein, and returned oxygenated through either the right common carotid artery (venoarterial bypass), or into a large vein (venovenous bypass). All patients treated must be free of coagulopathies, as all patients are anticoagulated. Neonatal candidates should be older than 34 weeks gestational age and weigh more than 2000 grams. As of March, 1997 twenty six patients have been treated with extracorporeal life support at Tulane Medical Center with an overall survival rate of 62%. Twelve neonates with either meconium aspiration or pneumonia have been treated with a 100% survival. Six children with congenital diaphragmatic hernia have been unsuccessfully treated.

Extracorporeal Membrane Oxygenation↗

PubMed2006

The morphological features of major and accessory fissures observed in different lung specimens.

The current study reports the presence of accessory fissure and anomalies in the major fissure and lobation in both the right and left lungs. The results indicated that out 102 lung specimens observed in the dissection room 37.26% appeared to have fissural or lobation anomalies and 63% of the anomalies were described in the right lung. Fissural anomalies accounted for 28.44% while the lobation anomalies were observed in 8.82% of the specimens. The abnormal fissure that were observed included the left minor fissure 10.78%, incomplete horizontal fissure 7.84%, diaphragmatic fissure 7.84%, right minor fissure 0.98% and azygos fissure 0.98%. Further observation revealed that 5.88% of the right lungs appeared to have two lobes and 2.94% of the left lungs had three lobes. The current study indicates that the right lung is commonly affected with fissural and lobation anomalies and that the left minor fissure is the commonly occurring fissural anomaly. Documentation and familiarization of these anomalies remain to be important for making correct radiological diagnosis and also for proper surgical management of lung pathology.

Cadaver↗

PubMed1978

Computer-aided measurement of breath volume and time components using magnetometers.

A computer-assisted method is developed for analyzing volume and time components of individual breaths using a previously developed magnetometer method for recording anteroposterior (AP) diameters of rib cage and abdomen. Calibration constants for the magnetometer system are computed during simultaneous measurements of airflow at the mouth for several breaths during spontaneous breathing. Tidal volume and inspiratory and expiratory times can then be computed from the magnetometer signals alone, without imposing respiratory devices at the subject's airway. No respiratory isovolume maneuvers are necessary. Results from normal subjects and from one patient with bilateral diaphragmatic paralysis show that the magnetometer analysis is closely comparable to standard measurements made from airflow recordings. The magnetometer technique thus provides an accurate means of measuring volume and time components of breathing in man, avoiding the behavioral or reflex effects induced by mouthpiece, nose clip, or face mask. Because no special respiratory maneuvers are required for calibration, the technique will be well suited to the study of breathing in those who are ill.

Abdomen↗

PubMed1999

Mucous fistula refeeding in neonates with short bowel syndrome.

BACKGROUND/PURPOSE: Neonates with enterostomies commonly suffer from a functional short bowel syndrome (SBS) and have a greater risk of electrolyte and fluid loss with poor weight gain. The authors describe their experience with refeeding stoma effluent into the mucous fistula in neonates. METHODS: A 5-year (1993 to 1997) chart review of neonates with stoma effluent refeeding was undertaken. Demographics, medical history, surgical procedures, timing, and duration of refeedings were reviewed. Enteral and total parenteral nutritional (TPN) requirements, electrolyte, and acid-base disturbances were recorded. RESULTS: Six neonates (gestational ages of 27 to 38 weeks, birth weights of 533 to 3400 g) were identified with nutritional or electrolyte complications before the commencement of refeeding. Enterostomy indications included necrotizing enterocolitis (n = 2), intestinal atresia type 3b (n = 1), complications from ruptured omphalocoele (n = 1), congenital adhesive band obstruction (n = 1), and midgut volvulus after congenital diaphragmatic hernia repair (n = 1). Weight gain during refeeding ranged from 5 to 25 g/kg/d with duration of refeeding lasting 16 to 169 days (two neonates were refed at home) until reanastomoses were done 6 to 44 weeks after the original surgery. There were no complications, and TPN requirements were diminished or eliminated. CONCLUSION: This technique represents a simple and safe method, which lessens the need for TPN and electrolyte supplementation in neonates with enterostomies and SBS before reanastomosis.

Enteral Nutrition↗

PubMed1998

Mouth occlusion pressure, CO2 response and hypercapnia in severe chronic obstructive pulmonary disease.

The resting mouth occlusion pressure 0.1 s after onset of inspiration (P0.1) and minute ventilation (V'E) and their response to CO2 in patients with chronic obstructive pulmonary disease (COPD) remain controversial. The ventilatory drive and the factors that predict resting arterial CO2 tension (Pa,CO2) were studied in 19 eucapnic and 14 hypercapnic severe COPD patients, and 20 controls. The CO2 response was evaluated by the Read technique. The V'E, and P0.1 as a function of end-tidal CO2 tension (Pet,CO2) was used to study the ventilatory (deltaV'E/deltaPet,CO2) and P0.1 response (deltaP0.1/deltaPet,CO2). In the patients, respiratory muscle function and pleural occlusion pressure 0.1 s after onset of inspiration (Ppl,0.1) were evaluated with simultaneous measurement of pleural (Ppl) and gastric (Pga) pressures. Hypercapnic patients had lower forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and arterial O2 tension (Pa,O2). Resting P0.1 was higher in patients than in controls, whereas deltaP0.1/deltaPet,CO2 was similar in the three groups. There was no difference in resting P0.1 (3.6+/-2.0 versus 4.3+/-2.8 kPa (2.7+/-1.5 versus 3.2+/-2.1 cmH2O), p=0.2) and Ppl,0.1 (1.4+/-2.3 versus 5.2+/-3.3 kPa (4.08+/-1.7 versus 3.9+/-2.5 cmH2O), p=0.22) between eucapnic and hypercapnic COPD, whereas deltaV'E/deltaPet,CO2 was lower in the hypercapnic group (0.29+/-0.24 versus 0.66+/-0.5 L x min(-1) x kPa, p<0.001). By logistic regression only FEVI and increased diaphragmatic load, and not respiratory drive, predicted resting Pa,CO2. Irrespective of CO2 level, baseline central drive (represented by the mouth occlusion and pleural pressures) and CO2 response are preserved in most patients with severe chronic obstructive pulmonary disease. Effective ventilation is inadequate in the more severely obstructed patients and this results in hypercapnia. Neuroventilatory coupling failure is an attractive explanation for chronic hypercapnia in these patients.

Aged↗

PubMed2004

Laparoscopic left-sided Nissen fundoplication in children.

It is sometimes difficult or inappropriate to adopt the standard surgical steps of adult laparoscopic procedures in pediatric patients because of the inevitably smaller anatomical structures and confined intra-abdominal working space. During laparoscopic Nissen fundoplication difficulties are usually encountered, especially when dissecting the diaphragmatic crura, creating the retroesophageal window, and repairing the crura. Thus, we devised a technique to accomplish these steps in pediatric patients. Both crural dissection and repair are approached from the left side of the esophagus and the port configuration for the laparoscope and other instruments is altered, providing better surgical exposure and easier handing of the instruments, even in very small patients. We describe this technique in detail and our results.

Adolescent↗

PubMed2006

Evaluation of pulmonary function using breathing chest radiography with a dynamic flat panel detector: primary results in pulmonary diseases.

OBJECTIVES: Dynamic flat panel detectors (FPD) permit acquisition of distortion-free radiographs with a large field of view and high image quality. The present study was performed to evaluate pulmonary function using breathing chest radiography with a dynamic FPD. We report primary results of a clinical study and computer algorithm for quantifying and visualizing relative local pulmonary airflow. MATERIALS AND METHODS: Dynamic chest radiographs of 18 subjects (1 emphysema, 2 asthma, 4 interstitial pneumonia, 1 pulmonary nodule, and 10 normal controls) were obtained during respiration using an FPD system. We measured respiratory changes in distance from the lung apex to the diaphragm (DLD) and pixel values in each lung area. Subsequently, the interframe differences (D-frame) and difference values between maximum inspiratory and expiratory phases (D-max) were calculated. D-max in each lung represents relative vital capacity (VC) and regional D-frames represent pulmonary airflow in each local area. D-frames were superimposed on dynamic chest radiographs in the form of color display (fusion images). The results obtained using our methods were compared with findings on computed tomography (CT) images and pulmonary functional test (PFT), which were examined before inclusion in the study. RESULTS: In normal subjects, the D-frames were distributed symmetrically in both lungs throughout all respiratory phases. However, subjects with pulmonary diseases showed D-frame distribution patterns that differed from the normal pattern. In subjects with air trapping, there were some areas with D-frames near zero indicated as colorless areas on fusion images. These areas also corresponded to the areas showing air trapping on computed tomography images. In asthma, obstructive abnormality was indicated by areas continuously showing D-frame near zero in the upper lung. Patients with interstitial pneumonia commonly showed fusion images with an uneven color distribution accompanied by increased D-frames in the area identified as normal on computed tomography images. Furthermore, measurement of DLD was very effective for evaluating diaphragmatic kinetics. CONCLUSIONS: This is a rapid and simple method for evaluation of respiratory kinetics for pulmonary diseases, which can reveal abnormalities in diaphragmatic kinetics and regional lung ventilation. Furthermore, quantification and visualization of respiratory kinetics is useful as an aid in interpreting dynamic chest radiographs.

Adult↗

PubMed1986

Dyssynchronous breathing during arm but not leg exercise in patients with chronic airflow obstruction.

Some patients with chronic airflow obstruction experience dyspnea with mild arm exercise but not with more-intense leg exercise. To investigate why these patients have limited endurance during arm exertion, we studied ventilatory responses to exercise with unsupported arms in 12 patients with chronic airflow obstruction (mean [+/- SD] forced expiratory volume in one second, 0.68 +/- 0.28 liters). Unloaded leg cycling was also studied for comparison. In the five patients who had the most severe airflow obstruction, arm exercise was limited by dyspnea after 3.3 +/- 0.7 minutes, and dyssynchronous thoracoabdominal breathing developed. In the other seven patients, arm exercise was limited by the sensation of muscle fatigue after 6.1 +/- 2.0 minutes (P less than 0.05), and dyssynchronous breathing did not occur. None of the 12 patients had dyssynchronous breathing during unloaded leg cycling. Maximal transdiaphragmatic pressure, a measure of diaphragmatic fatigue, declined similarly after arm and leg exercise in both groups. During unsupported arm work, the accessory muscles of inspiration help position the torso and arms. We hypothesize that the extra demand placed on these muscles during arm exertion leads to early fatigue, an increased load on the diaphragm, and dyssynchronous thoracoabdominal inspirations. This sequence may contribute to dyspnea and limited endurance during upper-extremity exercise.

Adult↗

PubMed1978

[Surgical therapy of axial hiatal hernias and reflux disease. 1. Results of an inquiry among Swiss surgeons in 1977].

Of the 153 heads of surgical departments in Switzerland, 152 joined in an inquiry into diagnostic procedures, surgical indications, and types of procedure in the treatment of axial hiatal hernia and reflux disease. Fundoplication is by far the most frequent procedure. Of the modifications performed in complicated reflux disease, 34% are controversial. Surgery for hiatal hernia and reflux disease is performed 3 times less frequently in the German part of Switzerland than in the other parts. German-speaking surgeons ascribe to themselves a greater willingness to perform preoperative diagnostic procedures--endoscopy, radiological and non-radiological tests of esophageal function--than the surgeons of the other parts of Switzerland. However, the German-speaking surgeons are more reluctant than the other surgeons to perform surgery in patients with esophagitis. The German-speaking surgeons are even more reluctant to perform surgery on the basis of subjective symptoms. Axial hiatal hernia is considered a relative indication for surgery by half of Swiss surgeons. Only a few surgeons consider this condition an absolute indication for surgery.

Cardia↗