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 1,207 records · Page 67Linked to original sources

PubMed1980

Respiratory mechanics in quadriplegia. The respiratory function of the intercostal muscles.

Pulmonary mechanics and inspiratory muscle pressures were studied in relation to electromyograms (EMG) of the respiratory muscles in 10 chronic quadriplegic patients . Transdiaphragmatic pressures at maximal inflation were normal, but minimal pleural pressures at functional residual capacity (FRC) were reduced to about one half the normal values. On the basis of the parasternal intercostal EMG results, 2 groups were defined. In 8 patients (Group I), no electromyographic activity was found in the intercostal muscles, even during large inspiratory maneuvers. In 2 patients (Group II), both intercostal and diaphragmatic activities were recorded during inspiration, and intercostal EMG activity increased with increasing inspiratory volume. Group 1 patients had reduced FRC, transpulmonary pressure at FRC, and static expiratory compliance; therefore, the pressure-volume curves of the lungs resembled those obtained in patients with generalized weakness of the respiratory muscles. Specific compliance was normal in each patient, suggesting that the low compliance resulted in large part from the collapse of air spaces. Group 2 patients had FRC, transpulmonary pressure at FRC, and lung compliance values within normal limits. We concluded that longstanding paralysis of intercostal muscles causes marked alterations in the elastic properties of the lungs and reduces the passive (outward) recoil of the chest wall. These findings suggested that the intercostal muscles normally stabilize the chest wall and prevent lung collapse. Moreover, intercostal surface EMG recordings may help to identify tetraplegic patients who may be at risk of developing respiratory failure during rather minor insults to the respiratory system.

Adult↗

PubMed1991

Bedside assessment of phrenic nerve function in infants and children.

Phrenic nerve damage is widely recognized after cardiac operations and is associated with an increased morbidity and mortality. Retrospective studies in children have estimated a prevalence of phrenic damage of between 0.5% and 2.2%, but all these studies have limited their investigations to patients who have clinical problems postoperatively, and they have all used clinical or radiologic methods to diagnose the damage. These methods are indirect and hard to evaluate, making the accurate early diagnosis of phrenic nerve damage very difficult. Measurement of phrenic nerve conduction time (phrenic latency) allows direct evaluation of phrenic function and integrity, making it potentially much more specific than indirect methods. Using a simplified method of direct phrenic nerve stimulation, we have developed a method of measuring phrenic latency at the bedside in infants and children. A 1 Hz electrical stimulus is applied over the phrenic nerve in the neck and a diaphragmatic electromyogram from the seventh and eighth intercostal spaces is displayed on a storage oscilloscope. Phrenic latency can be measured directly from the screen. Using these methods we have now studied 37 children (aged 2 days to 15 years) before and after cardiac operations. Mean phrenic latency was 5.4 +/- 1.0 msec on the right and 5.4 +/- 1.0 msec on the left. Prolongation of phrenic latency by more than 2 msec was found in seven of 66 postoperative measurements (10.6%). These patients had a substantially worse postoperative course. We believe this technique to be an important contribution to the diagnosis of postoperative phrenic nerve damage, and one that can help in clinical practice to elucidate an important cause of postoperative morbidity and mortality.

Adolescent↗

PubMed1989

[Dynamics of the respiratory center activity during electrical stimulation of the diaphragmatic nerve].

The adoption of artificial rhythm of electrical stimulation of diaphragmatic nerve was found to be determined by the force and rate of artificial contractions of the diaphragm, by the concentration of barbiturates in the blood and by gaseous composition of inspired air in anesthetized dogs. The time interval between the onset of artificial contraction and onset of natural one seems to characterize functional activity of respiratory center and to result from inhibitory afferent effect of the lungs' mechanoreceptors, on the one hand, and from activating effects of central and peripheral chemoreceptors, on the other hand.

Animals↗

PubMed1984

Right ventricular function in coronary artery disease as assessed by two-dimensional echocardiography.

Two-dimensional echocardiography (2DE) was performed in 64 patients with coronary artery disease. There were 46 men and 18 women, aged 58.7 +/- 11.4 years. An apical four-chamber view, a two-chamber right ventricular (RV) view, and a subcostal four-chamber view were obtained in 58 of 64 (91%) patients. Regional wall motion abnormalities ( RWMA ) of the RV free or diaphragmatic wall were detected in 4 of 18 (22%) patients with acute inferior myocardial infarction (IMI) and in 3 of 14 (21%) patients with old IMI. All seven patients with RWMA by 2DE had two or more of the following findings: hypotension, second- or third-degree atrioventricular block, atrial arrhythmias, or ventricular tachycardia. The RV ejection fraction by first-pass radionuclide angiography was 19.7 +/- 8.3% in patients with IMI and RV RWMA by 2DE compared to 35.3 +/- 9.6% (p less than 0.005) in patients without. A hyperdynamic RV wall motion was seen in 12 of 15 (80%) patients with acute anterior MI (AMI). No RV RWMA was observed in 17 patients with greater than 75% obstruction of right coronary artery and absent infarction. Thus, RWMA of the right ventricle were detected by 2DE in 22% of patients with IMI and identified patients with clinically significant RV dysfunction, probably due to RV infarction; a compensatory hyperdynamic RV wall motion was observed in 80% of patients with acute AMI.

Adult↗

PubMed1987

Effect of hyperinflation and equalization of abdominal pressure on diaphragmatic action.

We tested the hypothesis that the mechanical arrangement of costal (COS) and crural (CRU) diaphragms can be changed from parallel to series when direct or indirect transmission of tension occurs. Ratio of rib cage to abdominal displacement (RC/AB) resulting from separate COS and CRU stimulations were used to measure RC expanding action. Hyperinflation in six dogs caused RC/AB with COS and CRU stimulations to change progressively from 0.53 +/- 0.07 (SE) and 0.03 +/- 0.05 at functional residual capacity (FRC) to -0.48 +/- 0.08 and -0.46 +/- 0.05 at 68% inspiratory capacity, respectively. Liquid substitution of abdominal contents in six other dogs equalized abdominal pressure swings (delta Pab), without changing chest wall elastic properties or geometry, or costal RC/AB (0.35 +/- 0.07 before and 0.33 +/- 0.06 after) but caused crural RC/AB to change from 0.01 +/- 0.05 to 0.31 +/- 0.01. We conclude that hyperinflation changes fiber orientation, allowing direct transmission of tension between COS and CRU, which become linked mechanically in series (the diaphragm acts as a unit with RC deflating action); and equalization of delta Pab causes indirect transmission of tension between COS and CRU, which become linked in series (the diaphragm acts as a unit with RC inflating action).

Abdomen↗

PubMed2001

Gene expression of insulin-like growth factor-1 and epidermal growth factor is downregulated in the heart of rats with nitrofen-induced diaphragmatic hernia.

Newborns with congenital diaphragmatic hernia (CDH) still have high mortality. Recently, a possible role of cardiac maldevelopment has been suggested. Human and experimental studies have demonstrated that heart weight is significantly reduced in the presence of CDH. Recent studies have suggested an important role for insulin-like growth factor-I (IGF-I) in the regulation of cardiac growth, structure, and function. Administration of IGF-I to normal rats has been shown to cause cardiac hypertrophy. Epidermal growth factor (EGF) plays an important role in cardiac differentiation and development. The aim of this study was to determine the gene-level expression of IGF-I and EGF in the hearts of rats with nitrofen-induced CDH using the reverse-transcription polymerase chain reaction technique (RT-PCR). CDH was induced in pregnant rats following administration of 100 mg nitrofen on day 9.5 of gestation (term 22 days). In control animals, the same dose of olive oil was given without nitrofen. Cesarean section was performed on day 21 of gestation. The fetuses were divided into three groups: normal controls (n = 8), nitrofen without CDH (n = 8), and nitrofen-induced CDH (n = 8). Total RNA was extracted from the hearts in each group and measured. mRNA was extracted from total RNA. RT-PCR was performed to evaluate mRNA expressions of IGF-I and EGF. Levels of mRNA were expressed as a ratio of band density divided by that of beta-actin, a housekeeping gene known to be expressed at a constant level. IGF-I mRNA expression was significantly decreased in CDH hearts (0.177 +/- 0.109) compared to controls (0.393 +/- 0.138) (P < 0.01) and nitrofen hearts without CDH (0.321 +/- 0.088) (P < 0.05). EGF mRNA expression was significantly decreased in CDH hearts (0.218 +/- 0.118) compared to controls (0.534 +/- 0.196) (P < 0.01) and nitrofen hearts without CDH (0.383 +/- 0.136) (P < 0.05). Decreased cardiac gene expression of IGF-I and EGF in the hypoplastic heart suggests that cardiac hypoplasia in nitrofen-induced rat CDH may be due to reduced synthesis of IGF-I and EGF by myocytes in the developing heart.

Animals↗

PubMed1994

Experimental fetal tracheal ligation reverses the structural and physiological effects of pulmonary hypoplasia in congenital diaphragmatic hernia.

Infants with congenital diaphragmatic hernia (DH) and profound pulmonary hypoplasia are currently unsalvageable. The authors previously demonstrated that tracheal ligation (TL) accelerates fetal lung growth and reverses the pulmonary hypoplasia of fetal nephrectomy. The purpose of this study was to determine if the pulmonary hypoplasia of experimental DH could be similarly reversed and, if so, whether the resulting lungs would show better function than those of their DH counterparts. Eighteen fetal lambs were divided into three experimental groups of six animals each. In group 1, DH was created at 90 days' gestation. In group 2, DH was created at 90 days' gestation and TL performed during the same operation. Group 3 consisted of sham-operated controls. These animals were delivered near full-term, and their lungs analyzed by standard morphometric techniques. Ten additional fetal lambs were divided into two experimental groups of five animals each. In group 4, DH was created at 90 days' gestation. In group 5, DH was created at 90 days' gestation and TL performed 20 days later, at 110 days' gestation. These animals were pressure-ventilated via tracheostomy over a 2-hour period in which PaO2, PaCO2, and compliance were measured. Intratracheal pressure (ITP) was measured at the time of delivery in all groups. Upon retrieval, DH animals had abdominal viscera in the chest and small lungs; in contrast, DH/TL animals had the herniated viscera reduced from the chest by enlarged lungs. DH/TL lungs showed markedly increased growth, with significant increases in lung volume:body weight ratio (LV:BW; P = .0001), alveolar surface area (ALV.SA; P = .0001), and alveolar number (ALV#) (P = .0001) when compared with those of the DH or control group. This growth was associated with a normal maturation pattern based on histological appearance, normal airspace fraction, and normal alveolar numerical density. ITP in the DH/TL group was increased when compared with that of DH and control animals (P = .0001). Total lung DNA and protein were both elevated in the DH/TL animals (P = .0001). However, the DNA:protein ratio remained normal, suggesting lung growth had occurred through cell proliferation, not by hypertrophy. When ventilated over a range of settings, DH/TL lungs were more compliant (P = .0001) and achieved higher PaO2s (P < .003) and lower PaCO2s (P = .0001) than their DH counterparts. From these data, the authors conclude: (1) Experimental fetal DH produces hypoplastic lungs that are not capable of adequate gas exchange with conventional ventilation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1997

Relationship between transdiaphragmatic and mouth twitch pressures at functional residual capacity.

The clinical application of transdiaphragmatic twitch pressure (Pdi,tw) response to phrenic nerve stimulation has been hindered by the requirement for placement of oesophageal and gastric balloons. Investigators have reported that mouth twitch pressure (Pmo,tw) estimates Pdi,tw accurately at lung volumes above and below functional residual capacity (FRC). However, it is not known whether Pmo,tw estimates Pdi,tw accurately when stimulation is performed at FRC during relaxed conditions. The aim of this study was to develop a simple method whereby measurements of Pmo could be used to predict oesophageal twitch pressure (Poes,tw) and possibly Pdi,tw at FRC. The study was performed in 11 healthy volunteers during phrenic nerve stimulation. At FRC, 9 of the 11 subjects showed a poor correlation between Pmo,tw and Poes,tw, and between Pmo,tw and Pdi,tw, probably due to varying degrees of glottic closure. Stimulations performed while subjects maintained an inspiratory flow of approximately 50 mL x s(-1), or at the point of reattaining FRC during an inspiration preceded by a limited exhalation, produced good correlations between Pmo,tw and Poes,tw (r=0.97 in both instances) and Pmo,tw and Pdi,tw (r=0.96 and r=0.95, respectively), with a steep slope. The respective slopes for the Pmo,tw Poes,tw relationship were 0.88 and 0.94, and for the Pmo,tw Pdi,tw relationship, 0.59 and 0.54. Unfortunately, these manoeuvres produced a significant increase in transpulmonary pressure (3.6+/-0.6 (SE) and 5.6+/-1.4 cmH2O, respectively), suggesting change in diaphragmatic length. Stimulations delivered while subjects performed an inspiratory effort or during exhalation against a high resistance preceded by a limited inhalation could not be used to predict Poes,tw and Pdi,tw from Pmo,tw. In conclusion, although transdiaphragmatic and oesophageal twitch pressure could be predicted from mouth twitch pressure during some inspiratory manoeuvres mouth twitch pressure was not reliable for the prediction of the oesophageal and transdiaphragmatic twitch pressure at functional residual capacity during relaxed conditions in healthy volunteers.

Adult↗

PubMed2006

Array comparative genomic hybridization in patients with congenital diaphragmatic hernia: mapping of four CDH-critical regions and sequencing of candidate genes at 15q26.1-15q26.2.

Congenital diaphragmatic hernia (CDH) is a common birth defect with a high mortality and morbidity. There have been few studies that have assessed copy number changes in CDH. We present array comparative genomic hybridization data for 29 CDH patients to identify and map chromosome aberrations in this disease. Three patients with 15q26.1-15q26.2 deletions had heterogeneous breakpoints that overlapped with the critical 4 Mb region previously delineated for CDH, confirming 15q26.1-15q26.2 as a critical region for CDH. The three other most compelling CDH-critical regions for genomic deletions based on these data and a literature review are located at chromosomes 8p23.1, 4p16.3-4pter, and 1q41-1q42.1. Based on these recurrent deletions at 15q26.1-15q26.2, we hypothesized that loss-of-function mutations in a gene or genes from this region could cause CDH and sequenced six candidate genes from this region in more than 100 patients with CDH. For three of these genes (CHD2, ARRDC4, and RGMA), we identified missense changes and that were not identified in normal controls; however, none of these alterations appeared unambiguously causal with CDH. These data suggest that CDH caused by chromosome deletions at 15q26.2 may arise because of a contiguous gene deletion syndrome or may have a multifactorial etiology. In addition, there is evidence for substantial genetic heterogeneity in CDH and diaphragmatic hernias can be non-penetrant in patients who have deletions involving CDH-critical regions.

Case-Control Studies↗

PubMed1987

Quantitative regional curvature analysis: an application of shape determination for the assessment of segmental left ventricular function in man.

All traditional techniques of regional ventricular function analysis depend upon one or more assumptions about coordinate, reference, or indexing systems, idealized ventricular geometry, and the uniformity of ventricular contraction. Therefore, a method of shape analysis was developed that allows the quantitation of regional curvature and is independent of the assumptions outlined. This was implemented on a commercial image processing unit and applied to silhouettes of 30-degree right anterior oblique left ventriculograms. Three groups with abnormal wall motion (anterior abnormality, n = 23; inferior abnormality, n = 23; anterior and inferior abnormalities, n = 22) were analyzed and compared to a group with normal regional function (n = 22). Relatively few significant quantitative curvature differences were noted at end diastole among the groups. These few abnormalities described a slight increase in curvature or globularity of the anterior and inferior walls. More marked and extensive aberrations were detected at end systole. The group with anterior wall motion disturbances showed four distinct areas of curvature abnormality. Excessive curvature was present on either side of the apex (anterior and inferoapical regions) and apical curvature was less than normal. The fourth region was in the inferior zone, which showed curvature values that were less than normal, suggesting increased inward motion contralateral to the anterior abnormality. The group with inferior wall motion abnormalities also showed excessive end-systolic curvature on either side of the apex (diaphragmatic and anteroapical zones) and deficient curvature at the apex. A combination of these regional morphologic abnormalities was noted in the group with both anterior and inferior dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗

PubMed1992

Diaphragmatic contraction band necrosis in a perinatal and infantile autopsy population.

A morphologic study of the anterolateral costal diaphragm in 125 newborns and infants who died suddenly showed that contraction band necrosis is a common finding. In cases that showed the most extensive lesions, acute asphyxia was the usual mode of death; within eight diagnostic categories birth asphyxia (11 of 26 cases) and sudden infant death syndrome (19 of 30 cases) had the highest frequency of lesions. It was more frequent than myocardial contraction band necrosis and myocardial coagulation necrosis among the cases studied. The morphologic age and, if present, the stage of healing in each case suggested that the diaphragmatic lesion commenced at or shortly before death or at the time of the cardiac arrest that led to death. Thus, the lesion appeared to represent a very early event after a lethal injury, but it had no specificity for the nature of the injury. Because skeletal muscle of the respiratory diaphragm structurally and functionally resembles myocardium, the pathogenesis of contraction band necrosis may be similar in the two muscle types.

Autopsy↗

PubMed1989

Bochdalek's hernia combined with agenesis of the pericardium and intrathoracic solitary cyst of the liver.

A unique case of a neonate with agenesis of the fibrous pericardium combined with Bochdalek's foramen presenting herniation of a solitary cyst of the liver into the left hemithorax is presented. It is emphasised that the lack of the pericardium has not interfered with normal function of the heart, one year after the operation. The possible pathogenesis and embryology of this combination of malformations is discussed.

Cysts↗

PubMed2003

Respiratory effects of the scalene and sternomastoid muscles in humans.

Previous studies have shown that in normal humans the change in airway opening pressure (DeltaPao) produced by all the parasternal and external intercostal muscles during a maximal contraction is approximately -18 cmH(2)O. This value is substantially less negative than DeltaPao values recorded during maximal static inspiratory efforts in subjects with complete diaphragmatic paralysis. In the present study, therefore, the respiratory effects of the two prominent inspiratory muscles of the neck, the sternomastoids and the scalenes, were evaluated by application of the Maxwell reciprocity theorem. Seven healthy subjects were placed in a computed tomographic scanner to determine the fractional changes in muscle length during inflation from functional residual capacity to total lung capacity and the masses of the muscles. Inflation induced greater shortening of the scalenes than the sternomastoids in every subject. The inspiratory mechanical advantage of the scalenes thus averaged (mean +/- SE) 3.4 +/- 0.4%/l, whereas that of the sternomastoids was 2.0 +/- 0.3%/l (P < 0.001). However, sternomastoid muscle mass was much larger than scalene muscle mass. As a result, DeltaPao generated by a maximal contraction of either muscle would be 3-4 cmH(2)O, which is about the same as DeltaPao generated by the parasternal intercostals in all interspaces.

Adult↗

PubMed2005

Diaphragmatic paralysis caused by cervical spondylosis. Case report.

The authors describe a rare case of diaphragmatic paralysis caused by cervical spondylosis. A 64-year-old man presented with dyspnea as well as cervical radicular pain and left-sided upper-extremity motor weakness. Chest radiography revealed elevation of both sides of the diaphragm. All symptoms were ameliorated immediately after cervical laminoplasty, and spirometry revealed improvement of ventilatory function 6 months after surgery. Cervical spondylosis should be considered a factor that can cause respiratory dysfunction.

Cervical Vertebrae↗

PubMed1997

Influence of neck muscles on mouth pressure response to cervical magnetic stimulation.

Measurement of mouth pressure (Pm) in response to electrical phrenic nerve stimulation (Es) provides a simple noninvasive means to assess diaphragm function. An even simpler measure would be to use the Pm twitch response (Pm,t) to cervical magnetic stimulation (CMS) rather than to Es. Because CMS coactivates the diaphragm and inspiratory neck muscles (INM), CMS-Pm,t accurately reflects diaphragm function only if the corresponding INM contraction does not produce inspiratory pressures by itself. In patients with recent-onset bilateral diaphragm paralysis, it has been demonstrated that CMS-Pm,t was indeed zero; however, INM hypertrophy could change this situation and lead CMS-Pm,t to overestimate the performance of the diaphragm. To address this issue, we studied nine patients with amyotrophic lateral sclerosis (ALS) who had evidence of diaphragmatic paralysis and compensatory hypertrophy and hyperactivity of inspiratory neck muscles. The response to CMS was described in terms of diaphragm electromyogram (EMG), Pm, and abdominal (AB) and rib cage (RC) motion. No EMG response to CMS could be observed in most cases, and CMS was always associated with AB paradox. Nevertheless, a negative Pm,t swing was recorded with an amplitude of -2.6 +/- 1.0 cm H2O (mean +/- SD). We conclude that inspiratory neck muscle hypertrophy can significantly influence the Pm response to CMS. This should be taken into account when using the CMS-Pm combination in patients with possible chronic diaphragm dysfunction.

Aged↗

PubMed2005

Heart-touching Chilaiditi's syndrome.

Symptomatic hepato-diaphragmatic interposition of a bowel loop or Chilaiditi's syndrome is a peculiar anatomical condition most often found by chance. Its described symptoms range from intermittent, mild abdominal pain and dyspepsia to acute intestinal obstruction. We report a case of hepato-diaphragmatic migration of the hepatic flexure of the colon associated to an unusual, heretofore unreported, angina-like pain exclusively evoked by the left lateral decubitus. To maximize the chance of observing anatomical changes in different postures, computed tomography of the chest and abdomen was performed after air insufflation into the colon. While frank herniation into the chest was excluded, the scan showed that the hepatic flexure-with the interposition of the diaphragm-came in contact with the right side of the heart in the left lateral, but not in the supine, decubitus. This finding was reproduced by echocardiography which also showed virtually unaltered hemodynamics after the change of posture. ECG, left and right ventricular global and regional function as well as cardiac injury markers also remained unchanged during the maneuver, indicating that the pain evoked by the latter was unlikely due to myocardial ischemia. This case suggests that Chilaiditi's syndrome should be included among the possible, although rare, causes of unexplained angina-like symptoms.

Aged↗

PubMed1988

NMR study of rat diaphragm exposed to metabolic and compensated metabolic acidosis.

When exposed to hypercapnia, several muscles deteriorate with respect to their mechanical performance. Exposure to metabolic acidosis and, perhaps surprisingly, to compensated metabolic acidosis has the same effect on the diaphragm. The mechanisms involved in these effects remain unclear. If the diaphragmatic intracellular pH (pHi) is assumed to decrease with hypercapnia, to remain unchanged during metabolic acidosis, and to increase during compensated metabolic acidosis, it would appear that different mechanisms must be responsible for the depreciation in the diaphragm's mechanical performance. The present experiments using 31P nuclear magnetic resonance (31P-NMR) spectroscopy were undertaken to determine the effect of metabolic acidosis and compensated metabolic acidosis on pHi and on high-energy phosphate metabolites in the resting rat diaphragm. A whole diaphragm was slightly stretched while being stitched onto a fiberglass mesh. The area approximated that at functional residual capacity. It was superfused in the NMR sample tube with a phosphate-free Krebs-Ringer bicarbonate solution [( HCO3-] = 6 meqO equilibrated with either 95% O2-5% CO2 or 98.75% O2-1.25% CO2). Spectra were acquired during 15-min intervals for control (30 min of normal Krebs-Ringer bicarbonate superfusate, equilibrated with 95% O2-5% CO2), for 120 min of exposure to either form of acidosis and for 60 min of recovery with normal superfusate. The pHi decreased rapidly during metabolic acidosis but did not change significantly during compensated metabolic acidosis. In both forms of acidosis, phosphocreatine declined gradually but not significantly, whereas ATP and inorganic phosphate did not change at all. The results suggest that HCO3- passes freely through the diaphragmatic sarcolemma, very much like the cardiac sarcolemma.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗

PubMed2003

[Effects of diltiazem on contractility and electromyographic activity of non-fatigued diaphragm in dogs].

BACKGROUND: No data are available for diltiazem on muscle function (contractility and electomyographic activity) of non-fatigued diaphragm. METHODS: Eighteen pentobarbital-anesthetized dogs were divided into 3 groups of 6 each: Group I received no drug; Group II received small-dose of diltiazem (0.1 mg.kg-1.h-1); Group III received large-dose of diltiazem (0.5 mg.kg-1.h-1). Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi), the difference between esophageal and gastric pressures. Diaphragmatic electromyographic activity (Edi) was measured by means of electrodes placed at the anterior portion of the crural and costal parts of the diaphragm. After measuring baseline values of Pdi and Edi at 20 Hz and 100 Hz stimulation, the study drug was administered for 30 min. RESULTS: With infusion of diltiazem, Pdi and Edi to each stimulus did not change in Groups II and III. In Group I, these variables also showed no change. CONCLUSIONS: Diltiazem, at doses below 0.5 mg.kg-1.h-1, does not affect contractility and electromyographic activity of non-fatigued canine diaphragm.

Animals↗