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Biomedical subjects

M Estenne

Publications and source records attributed to M Estenne.

At least 73 records · Page 4Linked to original sources
PubMed1993

Severe hemolysis due to a donor anti-D antibody after heart-lung transplantation. Association with lung and blood chimerism.

Hemolysis due to donor-derived red cell antibodies is a potential complication after minor ABO-mismatched solid organ transplantation. It has also been described in Rh-positive recipients receiving organs from previously isoimmunized Rh-negative donors. We report on a group O, Rh(D)-positive patient who received a heart-lung transplant from a group O, Rh(D)-negative donor presenting an anti-D antibody. Severe hemolytic anemia developed in the early postoperative period and lasted for 3 mo. Anti-D antibodies that were of donor origin were found in bronchoalveolar lavage fluid and serum. In addition, using the polymerase chain reaction for human leukocyte antigen class II genotyping, we were able to demonstrate the presence of a mixed population of donor and recipient cells in the lungs and the peripheral blood of the recipient. The chimeric state in the blood persisted until at least the fifty-seventh postoperative day. This first case report of hemolysis due to Rh(D) antibody after heart-lung transplantation emphasizes the need for routine red cell antibody screening of donors and for close monitoring of signs of red cell destruction in the recipient in cases of pretransplant donor isoimmunization.

Adult↗
PubMed1993

Dextroposition of the left lower lobe after heart-lung transplantation.

Immediately after heart-lung transplantation for cystic fibrosis, a patient had development of a right lower lobe retrocardiac density that persisted on all postoperative chest radiographs. A computed tomographic examination of the thorax performed 3 weeks after surgery showed that there was partial collapse of the left lower lobe in the right hemithorax. The patient required a posterolateral thoracotomy for cure.

Adult↗
PubMed1993

Radiation-induced pulmonary veno-occlusive disease.

Late occurrence of radiation-induced pulmonary pneumonitis and fibrosis is well documented. We report an unusual case of radiation induced veno-occlusive disease (VOD) occurring six years following mantle irradiation for Hodgkin's lymphoma. The patient developed severe pulmonary hypertension and cor pulmonale. A left lung transplantation was performed successfully and pathologic examination of the explanted lung showed severe changes compatible with VOD. In the absence of exposure to alternate therapeutic or toxic agents that may cause VOD, it is likely that radiation caused damage to the venular endothelium and caused progressive obliteration of the pulmonary vessels. Review of the literature reveals only a few similar reports of VOD mostly following radiation for bone marrow transplantation. We conclude that previous irradiation (even several years earlier) should be considered as a possible cause of pulmonary VOD.

Adult↗
PubMed1992

Action of the diaphragm during cough in tetraplegic subjects.

Subjects with traumatic tetraplegia use the pectoralis major to compress the upper rib cage and increase intrathoracic pressure during cough. It is not known, however, whether they also contact the diaphragm during the expiratory phase of cough, as normal subjects do. We have investigated the action of the diaphragm during single voluntary coughing efforts in subjects with complete transection of the lower cervical (n = 5) or midthoracic (n = 2) cord. All subjects showed at least one peak of transdiaphragmatic pressure during the expiratory phase of the effort, and simultaneous bursts of electrical activity were recorded from the diaphragm. Coughing also resulted in an outward (paradoxical) motion of the abdomen during the compressive phase. We conclude that antagonistic contraction of the diaphragm is present during the expiratory phase of cough in spinal cord-injured subjects with paralysis of the abdominal muscles; this contraction, therefore, does not occur in response to activation of these muscles. The present results also indicate that the cough-induced paradoxical expansion of the abdomen is due to contraction of the pectoralis major and not of the diaphragm.

Adult↗
PubMed1992

Mechanical implications of in vivo human diaphragm shape.

Using magnetic resonance imaging, we measured the three-dimensional form of the diaphragm in vivo in four supine relaxed subjects at functional residual capacity and calculated its total surface area, the right and left surface areas in the zone of apposition, and the principal radii of curvature as a function of height. The area of apposition comprised 45 +/- 1.5% (SE) of the total surface area of the diaphragm. Available data on the area of the central tendon indicate that a considerable part of the muscular part of the diaphragm is lung apposed. The curvature was linearly related to height over 7 cm of the posterior half of each hemidiaphragm. From the linear portion of this graph and assuming a vertical gradient of transdiaphragmatic pressure of 0.75 cmH2O/cm, we applied the Laplace law and calculated tensions of 54 and 32 g/cm for right and left sides, respectively. We conclude that the shape of at least part of the posterior half of the relaxed human diaphragm in the supine position at functional residual capacity can be explained by the Laplace law, suggesting that both the lung and abdominal contents behave sufficiently as fluids so that they do not impose their shape on the diaphragm. Because diaphragm muscle is partly lung apposed, it is unlikely that the diaphragm functions simply as a piston.

Adult↗
PubMed1992

Rib cage shape and motion in microgravity.

We studied the effect of microgravity (0 Gz) on the anteroposterior diameters of the upper (URC-AP) and lower (LRC-AP) rib cage, the transverse diameter of the lower rib cage (LRC-TR), and the xiphipubic distance and on the electromyographic (EMG) activity of the scalene and parasternal intercostal muscles in five normal subjects breathing quietly in the seated posture. Gastric pressure was also recorded in four subjects. At 0 Gz, end-expiratory LRC-AP and xiphipubic distance increased but LRC-TR invariably decreased, as did end-expiratory gastric pressure. No consistent effect was observed on tidal LRC-TR and xiphipubic displacements, but tidal changes in URC-AP and LRC-AP were reduced. Although scalene and parasternal phasic inspiratory EMG activity tended to decrease at 0 Gz, both muscle groups demonstrated an increase in tonic activity. We conclude that during brief periods of weightlessness 1) the rib cage at end expiration is displaced in the cranial direction and adopts a more circular shape, 2) the tidal expansion of the ventral rib cage is reduced, particularly in its upper portion, and 3) the scalenes and parasternal intercostals generally show a decrease in phasic inspiratory EMG activity and an increase in tonic activity.

Electromyography↗
PubMed1991

Effect of head-up tilt on neural inspiratory drive in the anesthetized dog.

To examine how anesthetized dogs compensate for the diaphragmatic shortening that occurs during head-up tilting, we measured the electroneurogram (ENG) of the C5 phrenic root and the electromyographic (EMG) activity of the parasternal intercostal and transversus abdominis muscles in eight spontaneously breathing animals during postural changes between supine (0 degree) and 80 degrees head-up. Both steady state ENG and EMG activities and first breath responses to tilting from 80 degrees head-up to supine were studied. These experiments have shown that: (1) anesthetized dogs respond to head-up tilting by increasing the neural drive to the costal diaphragm and parasternal intercostals; (2) this response, however, does not occur on the first breath and therefore cannot compensate for the immediate changes in diaphragmatic length; (3) the abdominal muscles, in contrast, show a first breath response to tilting and their activation is primarily responsible for the maintenance of tidal volume. Unlike in humans, increases in neural inspiratory drive in head-up anesthetized dogs are mediated by a chemoreceptive, rather than proprioceptive, feedback mechanism.

Anesthesia↗
PubMed1991

Action of intercostal muscles on the lung in dogs.

The action on the lung of interosseous intercostal muscles located in the third and the seventh interspaces was studied in 15 anesthetized-curarized supine dogs. Changes in pleural pressure, airflow rate, and lung volume produced by maximal stimulation of both intercostal muscle layers were measured at and above functional residual capacity (FRC). In five animals measurements were also obtained during isolated stimulation of the internal layer. At FRC, intercostal stimulation in the upper interspaces had invariably an inspiratory effect on the lung but no effect was detectable in the lower interspaces. Qualitatively similar results were obtained during isolated stimulation of the internal layer. Increasing lung volume reduced the inspiratory action of the upper intercostals and conferred an expiratory action to the lower intercostals. These results indicate the following: 1) when contracting in a single interspace, the external and internal intercostals have a qualitatively similar action on the lung; and 2) this action, however, depends critically on their location along the cephalocaudal axis of the rib cage: in the upper portion of the rib cage, both muscle layers have an inspiratory effect at and above FRC; in the lower portion of the rib cage, they have no respiratory action at FRC and act in the expiratory direction at higher lung volumes.

Animals↗
PubMed1991

Lung and chest wall mechanics in microgravity.

We studied the effect of 15-20 s of weightlessness on lung, chest wall, and abdominal mechanics in five normal subjects inside an aircraft flying repeated parabolic trajectories. We measured flow at the mouth, thoracoabdominal and compartmental volume changes, and gastric pressure (Pga). In two subjects, esophageal pressures were measured as well, allowing for estimates of transdiaphragmatic pressure (Pdi). In all subjects functional residual capacity at 0 Gz decreased by 244 +/- 31 ml as a result of the inward displacement of the abdomen. End-expiratory Pga decreased from 6.8 +/- 0.8 cmH2O at 1 Gz to 2.5 +/- 0.3 cmH2O at Gz (P less than 0.005). Abdominal contribution to tidal volume increased from 0.33 +/- 0.05 to 0.51 +/- 0.04 at 0 Gz (P less than 0.001) but delta Pga showed no consistent change. Hence abdominal compliance increased from 43 +/- 9 to 70 +/- 10 ml/cmH2O (P less than 0.05). There was no consistent effect of Gz on tidal swings of Pdi, on pulmonary resistance and dynamic compliance, or on any of the timing parameters determining the temporal pattern of breathing. The results indicate that at 0 G respiratory mechanics are intermediate between those in the upright and supine postures at 1 G. In addition, analysis of end-expiratory pressures suggests that during weightlessness intra-abdominal pressure is zero, the diaphragm is passively tensed, and a residual small pleural pressure gradient may be present.

Abdomen↗
PubMed1990

Cough in tetraplegic subjects: an active process.

STUDY OBJECTIVE: To determine the role of the clavicular portion of the pectoralis major during cough in tetraplegic subjects. PATIENTS: Eight patients with longstanding traumatic transection of the lower cervical cord. METHODS: The electromyographic activity of the pectoralis major and abdominal external oblique muscles and the changes in the anteroposterior diameter of the lower rib cage, the upper rib cage, and the abdomen were measured during voluntary coughing efforts in the seated posture. RESULTS: When coughing, all subjects showed a large amount of electrical activity in the pectoralis major with no activity in the external oblique. Simultaneously, they had a clear-cut decrease in the anteroposterior diameter of the upper rib cage together with an increase in the anteroposterior diameter of the abdomen. In five subjects, the anteroposterior diameter of the lower rib cage also showed an initial increase. These changes were seen when cough was initiated at functional residual capacity or at a higher lung volume; they were also seen during a fit of coughing. CONCLUSIONS: In tetraplegic subjects the clavicular portion of the pectoralis major plays a major role during coughing. Its contraction causes a reduction in the size of the upper part of the rib cage and a rise in intrathoracic pressure; this pressure rise results secondarily in an outward (paradoxical) motion of the abdomen and the lower rib cage. Cough in tetraplegic subjects is thus an active, rather than a passive, process, and its effectiveness might be improved by a combination of specific muscle training and abdominal binding.

Abdomen↗
PubMed1990

Transversus abdominis muscle function in humans.

We used a high-resolution ultrasound to make electrical recordings from the transversus abdominis muscle in humans. The behavior of this muscle was then compared with that of the external oblique and rectus abdominis in six normal subjects in the seated posture. During voluntary efforts such as expiration from functional residual capacity, speaking, expulsive maneuvers, and isovolume "belly-in" maneuvers, the transversus in general contracted together with the external oblique and the rectus abdominis. In contrast, during hyperoxic hypercapnia, all subjects had phasic expiratory activity in the transversus at ventilations between 10 and 18 l/min, well before activity could be recorded from either the external oblique or the rectus abdominis. Similarly, inspiratory elastic loading evoked transversus expiratory activity in all subjects but external oblique activity in only one subject and rectus abdominis activity in only two subjects. We thus conclude that in humans 1) the transversus abdominis is recruited preferentially to the superficial muscle layer of the abdominal wall during breathing and 2) the threshold for abdominal muscle recruitment during expiration is substantially lower than conventionally thought.

Abdominal Muscles↗
PubMed1990

Chest wall motion and expiratory muscle use during phonation in normal humans.

The pattern of rib cage (RC) and abdomen (AB) motion and the electromyograms of the triangularis sterni (TS) and abdominal external oblique (EO) muscles were studied during speech and reading in six normal uninformed subjects in the sitting posture. Most phrases were started from within the tidal breathing range and extended below RC and AB spontaneous end-expiratory volumes. On the average, 75% of the change in chest wall volume occurred below the resting end-expiratory level. The expired volume resulted from a large predominance of RC displacement, and this was accompanied by marked recruitment of the TS. The EO was also generally activated, but the pattern of activation was less consistent. We conclude that 1) speech occurs primarily below the spontaneous end-expiratory level; 2) most of the volume change is caused by active emptying of the RC produced, at least in part, by contraction of the TS; 3) concomitant activation of the abdominal muscles serves to optimize the inspiratory function of the diaphragm, which has to contract rapidly between phrases to refill the respiratory system.

Adult↗
PubMed1990

Chest wall motion in paraplegic subjects.

To assess the isolated effect of an abnormal increase in abdominal compliance on the pattern of chest wall motion during breathing, we have studied seven patients with complete transection of the midthoracic cord (Th4-Th7). Measurements of chest wall motion were obtained with magnetometers, and concentric needle electrodes were used to record the electromyograms of various respiratory muscles. When breathing quietly in the seated posture, all patients had phasic inspiratory activity in both the scalenes and the parasternal intercostals in the cranial interspaces, and the upper and lower rib cage anteroposterior (AP) diameters increased proportionately and in phase. This confirms that the scalenes and the cranial parasternal intercostals are important determinants of the inspiratory expansion of the rib cage in humans. In six of the seven patients, however, the inspiratory increase in abdomen AP diameter was disproportionately larger than the increase in lower rib cage AP diameter. As a result, the tidal breathing loop was displaced to the right of the relaxed thoracoabdominal configuration. Binding the abdomen reduced or suppressed this deformation. These observations thus indicate that an isolated increase in abdominal compliance may cause the chest wall to depart from its relaxed configuration during breathing. This departure probably results from a combination of two factors: (1) a reduction in the rib cage expanding action of the diaphragm, and (2) a decrease in the activation of the rib cage inspiratory muscles relative to the diaphragm.

Abdominal Muscles↗
PubMed1990

Respiratory muscle incoordination in stuttering speech.

We investigated the role of respiratory muscle incoordination during stuttering by measuring esophageal, gastric, and transdiaphragmatic pressures to obtain subglottic pressure (Psg) and indices of diaphragmatic, rib cage, and abdominal muscle contraction during speech in normal volunteers and in severe stutterers. We found in contrast to the relatively constant subglottic pressure during normal conversational speech that speech in stutterers was characterized by failure to control Psg because of contraction of the diaphragm, rib cage, and abdominal muscles singly or in various combinations. As a result, Psg varied substantially and sometimes chaotically from too high to too low, rendering normal speech impossible. During periods of fluency, Psg was much better controlled. We conclude that incoordination of the respiratory muscles is a major problem in stuttering, resulting in failure to control the pressure difference across the vocal cords. It is unclear if this is a primary abnormality or is a secondary response to a primary abnormality elsewhere.

Adolescent↗