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Biomedical subjects

E D Robin

Publications and source records attributed to E D Robin.

At least 37 records · Page 2Linked to original sources
PubMed1989

Bronchial responsiveness to exercise after human cardiopulmonary transplantation.

Heart-lung transplant (HLT) recipients characteristically display marked bronchial hyperresponsiveness (BHR) to inhaled methacholine, but their bronchial responsiveness (BR) to exercise has not been reported. We measured BR to exercise in 13 stable HLT recipients, 13 normal control (NC) subjects and 13 asthmatic patients (AS). All subjects exercised for eight minutes on a bicycle ergometer at a work level designed to obtain and maintain 80 percent maximum heart rate, or to tolerance. The postexercise fall in FEV1 was equivalent in the HLT group and the NC group (0 +/- 0.2 L vs 0 +/- 0.2 L:p = NS) in contrast to the AS group (-0.6 +/- 0.5 L:p less than 0.01). Stable HLT recipients do not exhibit BHR to exercise at tolerable work loads. This observation supports the hypothesis that BHR to methacholine after HLT is due to denervation hypersensitivity of muscarinic receptors rather than other causes.

Adolescent↗
PubMed1989

Unexpected, unexplained sudden death in young asthmatic subjects.

The clinical course of asthma in four patients younger than 25 years was considered. Three died unexpectedly of their disease, and the fourth was successfully resuscitated after cardiopulmonary arrest. None of these patients met the criteria for status asthmaticus in the period preceding their death. The time course of the illness from apparent wellness to death was documented as seconds to minutes. No obvious cause of the severe disease was found at postmortem in two patients or by clinical analysis in all four. Patients with bronchial asthma may die with this disease unexpectedly, rapidly and with no obvious cause for the severity of this process.

Adolescent↗
PubMed1988

Mitochondrial DNA molecules and virtual number of mitochondria per cell in mammalian cells.

A new biochemical method for estimating the virtual number of mitochondria (mt) per cell was developed and used together with a plasmid probe to measure mt DNA/mitochondrion and mt DNA/cell. These methods were used in five cell types from four mammalian species. Mt DNA/mitochondrion was essentially constant in all cell types (mean 2.6 +/- 0.30 SE mitochondrial DNA molecules/mt). Mt DNA molecules/cell encompassed an eight-fold range between various cell types (low 220 +/- 6.2; high 1,720 +/- 162 mt DNA molecules/cell). Virtual mt number/cell ranged from 83 +/- 17 to 677 +/- 80 (SE) mt/cell in various cell types. All five mammalian virtual mitochondria contained the same genomic mass. The number of virtual mitochondria per cell and amount of mt DNA per cell appear to be closely regulated within a given cell type but differ widely from cell type to cell type.

Animals↗
PubMed1988

Effect of single respiratory manoeuvres on specific airway conductance in heart-lung transplant recipients.

1. The time course and magnitude of the effect of single slow and rapid respiratory manoeuvres on specific airway conductance (sGaw) was assessed in seven normal control subjects and in seven heart-lung transplant (HLT) recipients before and after experimentally induced bronchoconstriction. 2. Neither full inspiration, full exhalation nor vital capacity manoeuvres significantly altered sGaw in normal controls or HLT recipients under baseline conditions despite the presence of hyper-responsiveness to methacholine (MC) in the latter group. 3. After induced bronchoconstriction, single slow and rapid inspirations to total lung capacity transiently abolished or attenuated the bronchoconstriction in normal controls. This effect was absent in the HLT recipients. 4. In HLT recipients, the combination of hyper-responsiveness to MC, the absence of bronchoconstriction with respiratory manoeuvres and the absence of significant bronchodilatation after deep inspiration suggest lack of normal pulmonary innervation.

Adult↗
PubMed1988

Elastic behavior of the transplanted lung. Exponential analysis of static pressure-volume relationships.

We compared indices of muscle strength, parameters of mechanical lung function, and static pressure-volume curves in 12 heart-lung transplant (HLT) recipients to determine whether observed restrictive ventilatory defects represented abnormal elastic behavior of the transplanted lungs. Pressure-volume curves were analyzed using an exponential equation to generate the shape constant K, which describes the nonlinear behavior of pressure-volume relationships over a substantial range. For the group, K was 91% predicted, implying that there was not a diffuse abnormality of elastic properties of the transplanted lungs despite a mean TLC of 80% predicted. However, the mean maximal transpulmonary pressure (PLmax) was significantly low at 23.4 cm H2O (61% predicted) possibly related to the effects of surgery on thoracic cage mobility, but also in keeping with a reduction in power and efficiency of the thoracic musculature. The ability to achieve predicted TLC post-HLT was related to the preservation of optimal inspiratory force as TLC (% predicted) was highly correlated with maximal inspiratory pressure (PImax) (% predicted) (r = 0.83) (p less than 0.001). The ratio (TLC post-HLT)/(TLC pre-HLT) was 1.00 +/- 0.18 (r = 0.82) (p less than 0.005), suggesting donor organs were well matched to recipient chest cavities, but also emphasizing that the recipients had a low TLC prior to HLT. We conclude that the presence of a stable restrictive defect post-HLT is determined primarily by the volumetric constraints of the recipient chest cavity and within these constraints by the strength and efficiency of the thoracic musculature rather than a diffuse intrinsic abnormality of pulmonary elastic properties as a consequence of the transplantation process.

Adolescent↗
PubMed1988

Death from bronchial asthma.

There is now incontrovertible evidence that there is a progressive and strikingly increased mortality from bronchial asthma in the US. The increase is more dramatic in the older age groups, but younger age groups are not spared. The exact cause or causes of this increased mortality are not known, and it is even possible (although not likely) that the increase is artifactual. This increased death rate is in sharp contrast to the general medical perception that major advances in the management of bronchial asthma have occurred. Perhaps they have, but if so, more patients are dying during this period of advances than were dying before. The most prudent course would be to assume that the excess deaths are iatrogenic in origin and to act accordingly. Even if this assumption is flawed, acting on it would improve the management of patients with bronchial asthma. If it is true that the major purpose of risk-benefit analysis is to improve patient outcome rather than merely analyze risk-benefit balance, then a series of proposals can be generated to grapple with this problem in bronchial asthma.

Age Factors↗
PubMed1987

Overuse and abuse of Swan-Ganz catheters.

The widespread use of the Swan-Ganz catheter is a result of a general misconception. It is widely accepted that the collection of data is a way of practicing scientific medicine. That is simply not true. The data must on balance contribute to a better outcome for patients as established by a scientific trial. The present widescale use of the catheter provides a striking example of the misuse or even mindless use of technology. Because of a tenuous risk-benefit balance, it is not at all certain that the general use of the Swan-Ganz catheter is justifiable and its use at best is semi-scientific. A reasonable approach would be to suspend its use pending an appropriate clinical trial which established safety and efficacy. Although the prospects for a clinical trial are bright, the prospects for a moratorium are not at all bright. While awaiting the results of an appropriate trial, individual physicians should only use the catheter when the probability is high that the data obtained by its use will provide more effective decision making. Such an approach by itself should result in a near-moratorium. Its present use is not a form of scientific medicine but at best a form of semi-scientific clinical practice.

Catheters, Indwelling↗
PubMed1987

Hypoxic pulmonary vasoconstriction persists in the human transplanted lung.

The preservation of hypoxic pulmonary vasoconstriction (HPV) in the denervated lung was studied in five human heart-lung transplant recipients. All five patients showed significant increases in mean pulmonary artery pressure and pulmonary vascular resistance during hypoxic exposure, returning toward normoxic values during recovery. Aside from PAO2 and Pao2, other factors known to influence pulmonary vascular resistance did not change significantly during the hypoxic period. There was no relation between the length of the post-transplantation period and the intensity of HPV, suggesting that reinnervation of the pulmonary vascular bed did not account for persistent HPV and that HPV persists in the human transplanted lung despite the loss of autonomic neural innervation.

Adult↗
PubMed1987

Bronchial hyper-responsiveness after human cardiopulmonary transplantation.

1. Bronchial responsiveness to inhaled methacholine was studied in ten heart-lung transplant (HLT) recipients a mean 10.6 months (range 1.5-28 months) post-HLT and in ten normal subjects. 2. The mean provocation dose of methacholine producing a 20% fall in FEV1 (PD20 FEV1) was significantly lower in the HLT recipients (1.70 +/- 3.96 mg vs 11.55 +/- 3.79 mg; P less than 0.001), as was the mean provocation dose of methacholine producing a 50% fall in specific airway conductance (PD50 sGAW) (0.08 +/- 0.08 mg vs 5.13 +/- 5.47 mg; P less than 0.005). 3. These results establish the presence of significant bronchial hyper-responsiveness to inhaled cholinergic agonists in the transplanted lung.

Administration, Inhalation↗
PubMed1987

Pulmonary function in advanced pulmonary hypertension.

Pulmonary mechanical function and gas exchange were studied in 33 patients with advanced pulmonary vascular disease, resulting from primary pulmonary hypertension in 18 cases and from Eisenmenger physiology in 15 cases. Evidence of airway obstruction was found in most patients. In addition, mean total lung capacity (TLC) was only 81.5% of predicted and 27% of our subjects had values of TLC less than one standard deviation below the mean predicted value. The mean value for transfer factor (TLCO) was 71.8% of predicted and appreciable arterial hypoxaemia was present, which was disproportionate to the mild derangements in pulmonary mechanics. Patients with Eisenmenger physiology had significantly lower values of arterial oxygen tension (PaO2) (p less than 0.05) and of maximum mid expiratory flow (p less than 0.05) and significantly higher pulmonary arterial pressure (p less than 0.05) than those with primary pulmonary hypertension, but no other variables were significantly different between the two subpopulations. It is concluded that advanced pulmonary vascular disease in patients with primary pulmonary hypertension and Eisenmenger physiology is associated not only with severe hypoxaemia but also with altered pulmonary mechanical function.

Adolescent↗
PubMed1987

Iatroepidemics: a probe to examine systematic preventable errors in (chest) medicine.

Iatroepidemics are extreme examples of the inadequacies and errors that are prevalent in medicine. Their causes and evaluation are useful in demonstrating that medicine has a potentially destructive side as well as a highly constructive one. In the 1960s, the ATS left the sanitoria and joined the mainstream of medicine. In the 1980s it has become apparent that formal connections with science are not enough to ensure maximal safety for our patients. Nor are these connections sufficient to ensure maximal effectiveness of the measures we use to treat patients. A new awareness of our collective responsibility for improved patient outcome would be the obvious first step. Translating this sense of responsibility into new organizational approaches could place the ATS at the forefront of providing needed, and perhaps inevitable, reforms of medicine generally.

Diagnosis, Differential↗
PubMed1987

Primary pulmonary hypertension. Length of survival in patients referred for heart-lung transplantation.

The paucity of data on the natural history of primary pulmonary hypertension (PPH), and the observation that some patients awaiting heart-lung transplantation (HLT) appeared to be living longer than expected, led us to analyze the survival data of patients with PPH who had been referred for consideration of HLT. Ninety patients (female: male = 3.6:1) met clinical and hemodynamic criteria for PPH. Age at diagnosis was 29.8 +/- 7.9 years (mean +/- SD) (range 13-48 years). Symptom duration was 65.9 +/- 47.4 months, while survival from diagnosis was 42.9 +/- 42.6 months, giving a mean lead time of 23 months. Mean pulmonary artery pressure (PAP) at diagnosis was 61.6 +/- 15.0 mm Hg. The incidence of patent foramen ovale (PFO) was 19 percent, postpartum onset 16 percent, family history 6 percent, and cirrhosis 3 percent. The survival of 27 patients who died without operation was 50.3 +/- 52.5 months (median 37 months), with a symptom duration of 68.4 +/- 57.5 months (median 64 months). Both a high mean right atrial pressure (RAP) (p less than 0.025) and high mean PAP (p less than 0.025) correlated inversely with survival. For the whole group, none of the variables, age at diagnosis, sex, mean PAP or mean RAP at diagnosis, symptom duration prior to diagnosis or the presence of a PFO, postpartum onset or positive family history, significantly influenced survival. However, a low cardiac output (p less than 0.05) adversely influenced prognosis. The discrepancy between the mean and median length of survival in our group and previous reports confirms the need for further clarification of natural history and for appropriate clinical trials to assess therapeutic endeavors.

Adolescent↗