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Results for “Diaphragmatic function”

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At least 109 records · Page 6Linked to original sources

PubMed1992

Hemidiaphragmatic paresis during interscalene brachial plexus block: effects on pulmonary function and chest wall mechanics.

We studied the effects of unilateral hemidiaphragmatic paresis caused by interscalene brachial plexus block on routine pulmonary function in eight patients. In an additional four patients, we studied changes in chest wall motion during interscalene block anesthesia by chest wall magnetometry. Ipsilateral hemidiaphragmatic paresis, as diagnosed by ultrasonography, developed in all patients within 5 min of interscalene injection of 45 mL of 1.5% mepivacaine with added epinephrine and bicarbonate. Large decreases in all pulmonary function variables were measured in every patient. Forced vital capacity and forced expiratory volume at 1 s decreased 27% +/- 4.3% and 26.4% +/- 6.8%, respectively (P = 0.0001). Peak expiratory and maximum midexpiratory flow rates were also significantly reduced. Interscalene block caused changes in pulmonary function and chest wall mechanical motion that were similar to those published in previous studies on patients with hemidiaphragmatic paresis of pathological or surgical etiology. Interscalene block probably should not be performed in patients who are dependent on intact diaphragmatic function and in those patients unable to tolerate a 25% reduction in pulmonary function.

Adult↗

PubMed1993

Mammalian locomotor-respiratory integration: implications for diaphragmatic and pulmonary design.

Diaphragmatic function and intrapulmonary respiratory flow in running mammals were found to differ substantially from the corresponding conditions known in resting mammals. In trotting dogs, orbital oscillations of the diaphragm were driven by inertial displacements of the viscera induced by locomotion. In turn, oscillations of the visceral mass drove pulmonary ventilation independent of diaphragmatic contractions, which primarily served to modulate visceral kinetics. Visceral displacements and loading of the anterior chest wall by the forelimbs are among the factors that contribute to an asynchronous ventilation of the lungs and interlobar gas recycling. Basic features of mammalian respiratory design, including the structure of the diaphragm and lobation of the lungs, appear to reflect the mechanical requirements of locomotor-respiratory integration.

Animals↗

PubMed1976

Injuries to the phrenic nerve resulting in diaphragmatic paralysis with special reference to stretch trauma.

Traumatic interruption of the phrenic nerve causing diaphragmatic paralysis occurs much more commonly than realized. Patients present with symptoms referable to the respiratory, gastrointestinal, or cardiovascular systems as a result of anatomic displacement of the respective organ (eventration). Symptoms often occur shortly after the injury but may be delayed for many years; consequently, prolonged follow-up of these patients is essential. If patients are symptomatic after trauma, judicious observation is dictated, since many will experience gradual return of normal diaphragmatic function over the succeeding six to twelve months. In those who remain significantly symptomatic, thoracotomy and imbrication of the eventration is a simple and effective surgical procedure.

Adult↗

PubMedDate not supplied

Rod myopathy with extensive systemic and respiratory muscular involvement.

A patient with both muscle weakness and progressively degenerating respiratory function became increasingly less responsive to therapeutic intervention. The diagnosis of the muscle disease was made through biopsy samples and confirmed as rod myopathy. Through autopsy samples, the patient was found to have had extensive centriacinar emphysema and widespread involvement of rod disease in the skeletal muscles. The most involved of the muscles sampled (anterior tibial, brachioradialis, rectus femoris, psoas, diaphragm, biceps) was the diaphragm. While the influence on diaphragmatic function has been reported in the juvenile form of rod disease, this is the first known report of the extensiveness of involvement in adult-onset disease. The diseased state of the diaphragm was appreciated as a contributing factor to the respiratory insufficiency.

Adult↗

PubMed1980

The role of respiratory muscles in the hyperinflation of bronchial asthma.

To examine the mechanism of hyperinflation in bronchial asthma we studied lung and chest wall mechanics in 7 asymptomatic patients in whom progressive bronchoconstriction was induced by doubling the amount of inhaled aerosolized histamine. An increase in pulmonary resistance (RL) from 2.5 +/- 0.3 cmH2O . 1-1 . s (mean, +/- 1 SE) to 12.3 +/- 0.9 cmH2 was associated with a linear increase in functional residual capacity (FRC) up to 74.7 +/- 1.7% of control total lung capacity (TLCc). The mean regression coefficient was 2.3% TLCc . cmH2O-1 . 1 . s-1. At each level of hyperinflation the most positive expiratory pleural pressures measured during spontaneous breathing were generally less than the predicted chest wall relaxation pressures, indicating persistent inspiratory muscle contraction throughout expiration. This was predominantly due to inspiratory intercostal and accessory muscle activity, because measurements of transdiaphragmatic pressure indicated complete diaphragmatic relaxation early in expiration. Recruitment of abdominal muscles during expiration, inferred from measurements of gastric pressure (Pg) and abdominal antero-posterior (A-P) diameter, was progressively more apparent with increasing bronchoconstriction. We concluded that the increase in FRC in induced asthma is substantially influenced by persistent inspiratory intercostal and accessory muscle activity during expiration. Concomitant abdominal muscle recruitment results in a chest wall configuration that tends to optimize diaphragmatic function.

Abdomen↗

PubMed1993

Needle electromyography of the diaphragm: a new technique.

Electrodiagnostic evaluation of diaphragmatic function has consisted of phrenic nerve stimulation and surface or esophageal recordings of the electrical activity of the diaphragm. Needle electromyography of the diaphragm has rarely been reported because of the perceived danger of this procedure. We describe a new technique for needle electromyography of the diaphragm. An EMG electrode is placed in the costal insertion of the diaphragm under the 8th, 9th, or 10th rib cartilage, distant from the major vessels, pleura, lungs, and abdominal viscera. Diaphragmatic denervation was found in 42 of 81 patients using this method. There were no complications related to the procedure. Needle electromyography of the diaphragm provides important information in the diagnosis and management of respiratory dysfunction.

Adult↗

PubMed1981

Aminophylline improves diaphragmatic contractility.

In an attempt to explain the clinical efficacy of aminophylline, we studied its effect on diaphragmatic function in eight normal subjects. The relation between the electrical activity of the diaphragm and the pressure generated by the diaphragm was assessed during voluntary contractions before and after aminophylline infusion. Aminophylline shifted the electrical activity/pressure curve to the left; the pressure at a given electrical activity increased an average of 15 per cent (P less than 0.001). In four subjects, pressure was also measured during stimulation of the phrenic nerve at various frequencies before and after diaphragmatic fatigue was produced by resistive breathing, with and without aminophylline infusion. Pressure increased after fatigue at all stimulation frequencies with aminophylline, as compared with the pressure after identical fatigue runs at the same stimulation frequencies without aminophylline. The mean plasma aminophylline concentration associated with these responses was 13 +/- 0.9 mg per liter. We conclude that aminophylline improves the diaphragm's contractility and renders it less susceptible to fatigue.

Adult↗

PubMed1990

Chest wall motion of infants during spinal anesthesia.

To test the extent to which diaphragmatic contraction moves the rib cage in awake supine infants during quiet breathing, we studied chest wall motion in seven prematurely born infants before and during spinal anesthesia for inguinal hernia repair. Infants were studied at or around term (postconceptional age 43 +/- 8 wk). Spinal anesthesia produced a sensory block at the T2-T4 level, with concomitant motor block at a slightly lower level. This resulted in the loss of most intercostal muscle activity, whereas diaphragmatic function was preserved. Rib cage and abdominal displacements were measured with respiratory inductance plethysmography before and during spinal anesthesia. During the anesthetic, outward inspiratory rib cage motion decreased in six infants (P less than 0.02, paired t test); four of these developed paradoxical inward movement of the rib cage during inspiration. One infant, the most immature in the group, had inward movement of the rib cage both before and during the anesthetic. Abdominal displacements increased during spinal anesthesia in six of seven infants (P less than 0.05), suggesting an increase in diaphragmatic motion. We conclude that, in the group of infants studied, outward rib cage movement during awake tidal breathing requires active, coordinated intercostal muscle activity that is suppressed by spinal anesthesia.

Anesthesia, Spinal↗

PubMed1989

[Diaphragmatic fatigue and its role in the development of respiratory insufficiency and cor pulmonale in COPD].

Diaphragmatic function test was performed at rest and during maximal incremental exercise in six male normal non-smokers (Group A), sixteen male patients with COPD (58 +/- 8 yrs), including 4 with only small airway disorder (B) 6 with mild (C) and 6 with moderate airway obstruction (D) and eight patients with cor pulmonale complicated severe airway obstruction and chronic respiratory failure (E). Maximal transdiaphragmatic pressure (Pdi max) at rest in Group A, B, C, D, E were 13.6 +/- 2.9 kPa, 10.8 +/- 3.1 kPa, 9.9 +/- 3.4 kPa, 6.8 +/- 3.3 kPa and 5.3 +/- 2.5 kPa respectively, the latter two (D and E) being significantly lower than that of the normal control (D, P less than 0.05, E, P less than 0.01). Breathing pattern of the diaphragm at rest was similar to the normal control in all groups except that half of the patients in Group E (4/8) showed diaphragmatic paradoxical motion during inspiration. Ergometer test with incremental workload was performed in all groups except for Group E. During exercise, patients with COPD revealed some extent of diaphragmatic fatigue. All in group D(6/6) and most in group C(4/6) eventually developed inspiratory paradoxical motion of diaphragm before the ventilatory reserve was exhausted.

Aged↗

PubMed1983

Breathing patterns during curare-induced muscle weakness.

This study examines the pattern of breathing used by normal subjects to compensate for an acute decrease in muscle strength. A continuous infusion of curare was used to reduce peak inspiratory pressure in six normal subjects from normal control levels to -45 cm H2O (moderate weakness) and to -70 cm H2O (mild weakness). Before administration of curare, inspiratory pressure exceeded -120 cm H2O. A canopy-computer-spirometer system was used for noninvasive spirometry and measurements of gas exchange. Partial curarization to a mild level of muscle weakness did not produce significant changes in the respiratory functions studied. With a moderate level of muscle weakness, there were significant increases in tidal volume from 166 to 186 ml/m2 and in inspiratory time from 1.51 to 1.71 sec (P less than 0.05). Minute ventilation and inspiratory flow did not change. However, when given 3% CO2, both normal and partially curarized subjects increased minute ventilation, from 2.3 to 5.7 L/min/m2 and from 2.5 to 6.7 L/min/m2, respectively. The increases in both conditions were secondary to increases in tidal volume. There was also a small increase in respiratory frequency from 15.4 to 18 breaths/min, P less than 0.01 in the partially curarized group given 3% CO2. Because minute ventilation was preserved while vital capacity decreased, it is proposed that respiration is maintained in the presence of muscle weakness associated with curare by diaphragmatic function which remains relatively unaffected by curarization.

Adult↗

PubMed1986

Diaphragmatic fatigue and breathing pattern during weaning from mechanical ventilation in COPD patients.

The medium-term outcome of weaning from mechanical ventilation in COPD patients is not easy to anticipate because a respiratory fatigue may eventually develop. We evaluated the diaphragmatic function and the breathing pattern during 40 weaning trials on 15 patients ventilated after acute respiratory failure. We formed two groups according to the success (group B, n = 18) or failure (group A, n = 19) of the medium-term attempt (group A/less than 10 hours; group B/more than 12 hours). Provided the patients showed the classic weaning criteria (tidal volume greater than 5 ml/kg, respiratory frequency less than 30 breaths per minute, PaO2 greater than 50 mm Hg), the study of the breathing pattern did not allow differentiation between the groups. However, the transdiaphragmatic pressure (Pdi) and the Pdimax, which gave an indication of the power of diaphragm contraction, dropped early in the group that could not stand weaning, with an increase in the Pdi/Pdimax ratio. In addition, this same group showed a diaphragmatic dysfunction attested for by a frequent negative gastric pressure associated with or shortly preceded by an abdominal paradoxic motion.

Aged↗

PubMed1988

Diaphragm function after pulmonary resection. Relationship to postoperative respiratory failure.

We studied the lung mechanics and respiratory muscle function in 20 patients undergoing pulmonary resection. Transdiaphragmatic pressure (delta Pdi) during quiet breathing did not show any remarkable change after the operation (9.5 +/- 1.1 to 10.9 +/- 1.0 cm H2O), while the ratio of abdominal to transdiaphragmatic pressure changes (delta Pab/delta Pdi) revealed a significant difference between the preoperative and the early postoperative periods (0.32 +/- 0.06 to 0.00 +/- 0.11, p less than 0.05). The postoperative delta Pab/delta Pdi correlated significantly with the work of breathing (r = -0.60, p less than 0.01). The maximal transdiaphragmatic pressure (Pdimax) decreased significantly after operation (75.0 +/- 15.8 to 32.8 +/- 12.4 cm H2O, p less than 0.05), with no significant change in the maximal inspiratory mouth pressure (MIP) (74.2 +/- 16.8 to 39.5 +/- 11.6 cm H2O). Four of 20 patients developed respiratory failure postoperatively and required mechanical ventilation. delta Pab/delta Pdi in these patients was significantly lower than in the other patients (-0.62 +/- 0.24 versus 0.16 +/- 0.09, p less than 0.005). Our results suggested that during quiet breathing diaphragmatic function was preserved and intercostal/accessory muscles recruitment increased, but maximal strength of the diaphragm might be reduced in patients undergoing pulmonary resection.

Adult↗

PubMed1994

Clinically relevant diaphragmatic dysfunction after cardiac operations.

Phrenic nerve injury and diaphragmatic dysfunction can be induced by cardiac operation. The clinical consequences are not well-established. We evaluated 13 consecutive patients over a 2-year period with unexplained and prolonged difficulties in weaning from mechanical ventilation. The mean time of measurement from the operation day was 31 +/- 19 days (range 8 to 78). With the same technique we also evaluated 12 control patients: four patients at day 1 after cardiac operation while they were still intubated; four normally convalescing patients at day 7 or 8 after cardiac operation; and four patients who required prolonged mechanical ventilation because of another identified cause after cardiac operation. Diaphragmatic function was evaluated at the bedside from esophageal and gastric pressure measurements. A low or negative ratio of gastric pressure swing to transdiaphragmatic pressure swing, indicative of diaphragm dysfunction, was found in all 13 patients (mean -0.39 +/- 0.64). The difference between the 13 patients and all control groups was found to be highly significant. Transdiaphragmatic pressure measured during a maximal voluntary inspiratory effort and transdiaphragmatic pressure measured during a short, sharp sniff were markedly diminished (28 +/- 18 cm H2O and 13 +/- 15 cm H2O, respectively) in the 13 patients, significantly different from values in the four control patients studied at day 7 or 8. Transdiaphragmatic pressure measured after magnetic stimulation in four patients was also markedly reduced (7 +/- 5 cm H2O) as compared with normal theoretic values. Aminophylline infusion had no effect on any of these parameters. In one of two patients evaluated a second time, about 5 weeks later, a marked improvement was observed. Estimating the prevalence of clinically relevant diaphragmatic dysfunction, we found it to be 0.5% when no topical cooling was used and 2.1% when iced slush with no insulation pad was added for myocardial protection (p < 0.005). The most striking finding was that the clinical course of the 13 patients was marked by severe intercurrent events, including cardiorespiratory arrest after early tracheal extubation in 5 patients, nosocomial pneumonia in 11, prolonged mechanical ventilation in all (58 +/- 41 days), and a fatal outcome in 3. We conclude that prolonged postoperative diaphragmatic dysfunction may cause severe life-threatening complications after cardiac operation and can be limited to some extent by avoiding the use of iced slush topical cooling of the heart.

Adult↗

PubMed1975

Simplified operative technique for the long-segment atypical coarctation of the aorta.

Simplified operative technique for the long-segment atypical coarctation of the aorta was described. The main objective of this technique is to gain quick access to both thoracic and abdominal aorta with minimal blood loss, and preservation of diaphragmatic function. This procedure consists of standard thoracotomy and pararectal incision with an entry into the retroperitoneal space. Long prosthetic graft was anastomosed in an end-to-side fashion to bypass the coarctated aorta. The graft is placed through peripheral circumference of the left hemidiaphragm, where phrenic nerve injury is not likely to occur. This technique was successfully applied to two cases of long-segment atypical coarctation of the aorta due to Takayasu's aortitis. Retroperitoneal placement of the graft prevents fatal hemorrhage due to direct contact with the graft. Contamination with transintestinal exudate can also be avoided. Results of the ten-year follow-up of the similar procedure in the literature is encouraging.

Adult↗

PubMed1978

Bilateral diaphragmatic paralysis with hypercapnic respiratory failure. A physiologic assessment.

Bilateral diaphragmatic paralysis was suspected in a patient presenting with hypercapnic respiratory failure who exhibited paradoxic (i.e., inward) abdominal movement on inspiration during tidal breathing in the supine posture; no paradoxic abdominal motion was observed at the bedside with the patient upright. Transdiaphragmatic pressure measurements established the diagnosis of diaphragmatic paralysis, although 20 cm H2O pressure developed across the diaphragm during the latter part of a forced expiration, presumably due to the development of passive tension in the diaphragm as it was stretched near residual volume. Analysis of the relative motion of the rib cage and abdomen during breathing by the use of magnetometers confirmed the presence of abdominal paradox throughout the breathing cycle when the patient was supine, and established that paradoxic motion of the abdomen also occurred when the patient was in the erect posture but only in the latter half of inspiration. Our findings confirm that the use of transdiaphragmatic pressure measurements and magnetometry will help to quantify diaphragmatic function, that passive tension develops in the paralyzed diaphragm near residual volume and should not be confused with active contraction, and that paradoxic motion of the abdomen may be masked from the clinician when the patient is erect.

Aged↗

PubMed1990

Post cardiac surgery phrenic nerve palsy in pediatric patients.

From January 1978 to December 1988, 109 phrenic nerve paralyses (PNP) occurred in a total of 9149 cardiac operations performed in a population of patients younger than 15 years old (1.2%) whose age varied from 1 day to 15 years old and mean weight was 11.3 +/- 8.7 kg. PNP was diagnosed in 43 patients after closed procedures (1.2% of 3509 procedures) and in 66 patients after open heart operations (1.2% of 5640 operations). PNP was right sided in 49 cases and left sided in 60 cases. Open heart operations that predisposed to PNP were those which needed harvesting of autologous pericardium (P less than 0.0001) and wide exposure of the great vessels. The modified right Blalock-Taussig shunt was the main cause of PNP in closed procedures (P less than 0.02). Small children tolerated PNP less well. They needed longer ventilatory support (P less than 0.0005) and developed more respiratory complications. Seventeen children underwent plication of the affected hemidiaphragm and could be subsequently extubated. It is concluded that for prevention of PNP, a high level of attention should be exercised in neonates and small children, particularly when pericardium is harvested or when exposure needs extensive dissection of the great vessels and thymus resection, or at reoperation. We also prefer to avoid the use of iced slush lavage. PNP, when symptomatic, is best managed by continuous positive airway pressure (CPAP) ventilation. Diaphragmatic plication is recommended when after 2-3 weeks there is no recovery of diaphragmatic function or when there are troublesome respiratory complications.

Adolescent↗

PubMed1980

Neurogenic respiratory failure: a 5-year experience using implantable phrenic nerve stimulators.

During the past 5 years, 20 phrenic nerve stimulators have been implanted in 11 patients who were ventilator dependent because of neurogenic respiratory failure. Ten patients had traumatic spinal cord lesions; the remaining patient suffered from a progressive demyelinating disease. There was no operative mortality. Complications included 1 stimulator malfunction and 1 pneumothorax. In spite of adjacent tracheostomies, there were no infections or wound complications. Of the 20 stimulators implanted, 13 initially produced good diaphragmatic function, 2 had fair function, and 5 had little or not function. Three patients became completely independent of their ventilators; 6 became partially independent, thus simplifying nursing care. There were no late complications. As of December, 1979, 7 patients had benefited or were continuing to benefit from phrenic nerve stimulation.

Adolescent↗

PubMed1977

Topical cardiac hypothermia and phrenic nerve injury.

The relationship between ice-chip cardioplegia and impaired left diaphragmatic function was evaluated in dogs. Direct or indirect contact of the phrenic nerve with crushed ice for 30 or 60 minutes resulted in phrenic paralysis for 6 to 28 days, with responsiveness returning from 7 to 62 days later. Microscopical examination of injured nerves revealed injury to the myelin sheath and preservation of axons. Paralysis of the left diaphragm after topical cardiac hypothermia may be secondary to cold injury of the phrenic nerve, which is reversible.

Animals↗