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Biomedical subjects

C J Newth

Publications and source records attributed to C J Newth.

87 records · Page 5Linked to original sources
PubMed1981

Pregnancy in cystic fibrosis: a better prognosis in patients with pancreatic function?

Pregnancy in patients with cystic fibrosis is likely to become a more common occurrence as a result of improving survival rates in females with this condition. Eleven pregnancies in seven patients with cystic fibrosis are presented. Despite previous reports on the hazards of pregnancy in women with cystic fibrosis, only one pregnancy required a therapeutic abortion to preserve the health of the mother. Nine of the pregnancies occurred in five mothers who had no pancreatic insufficiency, and no significant deterioration in pulmonary function occurred during or after pregnancy. These patients who do not require pancreatic enzyme supplementation appear to represent a special subgroup within cystic fibrosis in whom not only pulmonary function but also the overall prognosis is better, and in whom pregnancy can be tolerated without undue hazard.

Adult↗
PubMed1981

Radiographic tracheal diameter measurements in acute infectious croup: an objective scoring system.

The percentage of change in tracheal diameter (TD% change), as assessed by an objective radiological measurement, was used along with a simple subjective clinical score to assess response to therapy in upper airway obstruction in 14 patients with acute infectious croup. Studies were performed on the 14 patients, each of whom was randomly assigned to one of two treatment groups: distilled water or racemic epinephrine (RE), both being nebulized and delivered by manual IPPB. The objective radiological assessment and the subjective clinical score both confirmed that RE is significantly (p less than 0.005) more effective than distilled water in the acute relief of upper airway obstruction. The more precise radiological assessment may be of value in determining objectively better drug therapy for infectious croup.

Airway Obstruction↗
PubMed1981

Thallium myocardial perfusion scans for the assessment of right ventricular hypertrophy in patients with cystic fibrosis. A comparison with other noninvasive techniques.

The incidence of right ventricular hypertrophy in 32 patients with cystic fibrosis was studied using thallium 201 (TI-201) myocardial perfusion scans, and compared with other noninvasive techniques including electrocardiography, vectorcardiography, and M-mode echocardiography. The patients (mean age, 17.3 yr; range, 7 to 33) had a wide range of clinical and pulmonary abnormalities (mean Shwachman-Kulczycki score, 66.6). In the total study group, TI-201 scans, like the vectorcardiograms and the M-mode echocardiograms, gave a surprisingly high proportion of positive predictions for right ventricular hypertrophy (RVH) (44%). The correlations with all other noninvasive methods were uniformly poor, so caution must be exercised in using this technique to predict early RVH in order to follow the natural history of cor pulmonale in cystic fibrosis. At the time of the study, 6 patients had clinical evidence of right ventricular failure, and in this disease setting must have had RVH. In 3 patients, RVH was confirmed at autopsy, and it was successfully predicted by TI-201 scans in 5 of the 6 patients. The false negative scan may have been due to regional myocardial ischemia secondary to severe right ventricular failure. In contrast, the vectorcardiogram, using Fowler's new criteria, made a successful prediction of RVH in all 6 patients, and the electro cardiogram in only 3. Although the M-mode echocardiogram was abnormal in all patients, it would have predicted RVH (with increased right ventricular anterior wall thickness) in only 1 patient. We concluded that TI-201 myocardial perfusion cans are good at confirming RVH in cases with established right ventricular failure, but have no advantage over vectorcardiographic assessments, which are logistically easier to perform and carry no radiation risks.

Adolescent↗
PubMed1980

Hemodynamic responses to supine exercise in children with left-sided cardiac disease.

Exercise, a physiologic stress, has been used in adults to unmask abnormalities of left ventricular hemodynamics not detectable at rest. Similar data in children are not available. An evaluation was made of the feasibility, safety and value of a graded upright and supine ergometer stress test to assess exercise hemodynamics during cardiac catheterization in 21 children with left-sided cardiac disease. The catheterization technique involved the simultaneous recording of intracardiac and great vessel pressures, thermodilution cardiac index and M mode echocardiograms of the left ventricular cavity. The method appears practical and safe. Although hemodynamic responses varied among clinical groups, the lack of control data currently prevents assessment of the value of this technique for long-term management.

Adolescent↗
PubMedDate not supplied

The assessment of pulmonary arterial pressures in bronchopulmonary dysplasia by cardiac catheterization and M-mode echocardiography.

Severe (Stage IV) bronchopulmonary dysplasia (BPD) has been associated with pulmonary hypertension and right heart failure, with a mortality rate of 39%. Recently, M-mode echocardiography has been used to measure right-sided systolic time intervals (the ratio of right ventricular pre-ejection period to ejection time; RVPEP/RVET), with a value greater than 0.35 predicting pulmonary hypertension. This measurement has also been used to predict outcome of BPD and response to oxygen therapy. A retrospective study of six infants with Stage IV BPD who had had cardiac catheterizations and M-mode echocardiography is reported. By catheterization criteria, four of the six had pulmonary hypertension. By echocardiographic criteria, only two of the six had unequivocally prolonged RVPEP/RVET ratios, and correlations with mean or diastolic pulmonary arterial pressures were poor (0.069 and 0.255, respectively). The validity of M-mode echocardiography in the assessment of the pulmonary vascular bed in Stage IV BPD is open to debate, and its role in predicting outcome and response to therapy is unknown.

Bronchopulmonary Dysplasia↗
PubMedDate not supplied

Urokinase therapy for a catheter-related right atrial thrombus and pulmonary embolism in a 2-month-old infant.

Thrombolytic therapy seems to be effective in clearing catheter-related thrombi, allowing subsequent reuse of the Broviac catheter. We have confirmed the previously theoretical risk that thrombolytic therapy in such cases may create pulmonary emboli, but such therapy (in our very limited experience) dissolves the clot extremely quickly. This latter observation may mean that thrombolytic therapy is particularly useful for pulmonary emboli in infants and young children.

Cardiac Catheterization↗
PubMedDate not supplied

The pharmacokinetics of dobutamine in pediatric intensive care unit patients.

Dobutamine is used for hemodynamic support in critically ill patients; however, due to the relative insensitivity of most available assays, there is little detailed information about its pharmacokinetics. We studied the pharmacokinetics of dobutamine in 27 children and infants using a high-sensitivity HPLC technique. The patients' ages ranged from 0.13 to 16.6 years; 17 received dobutamine for treatment of shock while 10 received it for treatment of post-cardiac surgery. Blood samples were collected before (N = 27) and after (N = 10, 9 time points each) the cessation of dobutamine infusion. The duration of dobutamine infusion before sampling was 1.87 +/- 0.29 days (range: 0.2-5.5; median: 1). The steady-state plasma concentration of dobutamine (infusion rate corrected to 5.0 micrograms/kg/min) was 105 +/- 19 ng/ml (range: 3.79-400; median: 76). The clearance rate was 151.1 +/- 47.5 ml/kg/min (range: 12.5-1319; median: 66). Most post-infusion time-concentration data were best fit to a biexponential function suggestive of a two-compartment model. The t1/2 alpha was 1.65 +/- 0.20 min (range: 0.64-3.01; median: 1.52) while the t1/2 beta was 25.8 +/- 11.5 min (range: 4.6-68.6; median: 16.9). Neither age, weight, sex, disease state, duration of infusion, nor blood measures of renal or hepatic dysfunction were found to be covariates of the above parameters. It was found, however, that the concomitant administration of dopamine altered dobutamine's pharmacokinetics, indicating the possible presence of a competitive component in dobutamine's disposition.

Child↗