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Biomedical subjects

G Weinmann

Publications and source records attributed to G Weinmann.

At least 19 recordsLinked to original sources
PubMed2000

Pulmonary artery catheterization and clinical outcomes: National Heart, Lung, and Blood Institute and Food and Drug Administration Workshop Report. Consensus Statement.

OBJECTIVE: The efficacy and safety of the pulmonary artery catheter are under scrutiny because of its association with increased morbidity and mortality in observational studies. In response, the National Heart, Lung, and Blood Institute (NHLBI) and the US Food and Drug Administration (FDA) conducted the Pulmonary Artery Catheterization and Clinical Outcomes workshop in Alexandria, Va, on August 25 and 26, 1997, to develop recommendations regarding actions to improve pulmonary artery catheter utility and safety. PARTICIPANTS: The NHLBI and FDA planning task force selected a workshop chairperson, subcommittee chairs, and participants. Approximately 85 participants were selected for their collective expertise in critical care, pulmonary medicine, cardiovascular medicine and surgery, pediatrics, nursing, biostatistics, and medical economics. The meeting was open to industry representatives and other government and lay observers. This workshop was funded by the NHLBI and the FDA's Division of Devices. EVIDENCE: Published reports relating to the efficacy and safety of the pulmonary artery catheter, especially consensus documents developed by professional societies. CONSENSUS PROCESS: The planning task force disseminated materials, held teleconferences, and developed draft position papers prior to the workshop. These were modified during the workshop and thereafter in the course of several teleconferences, and presented to the entire group for final modifications and approval. CONCLUSIONS: A need exists for collaborative education of physicians and nurses in performing, obtaining, and interpreting information from the use of pulmonary artery catheters. This effort should be led by professional societies, in collaboration with federal agencies, with the purpose of developing and disseminating standardized educational programs. Areas given high priority for clinical trials were pulmonary artery catheter use in persistent/refractory congestive heart failure, acute respiratory distress syndrome, severe sepsis and septic shock, and low-risk coronary artery bypass graft surgery. JAMA. 2000;283:2568-2572

Catheterization, Swan-Ganz↗
PubMed1993

Health effects and exposure assessment of aerosolized pentamidine handlers.

Nurses administering aerosolized pentamidine (AP) were studied to determine any effect AP may be having on their health. Exposure was determined by each nurse's self-report of treatment given as recorded in a daily log and personal and area pentamidine sampling. Outcome measures were self-reported symptoms recorded in a daily log and peak expiratory flow rates (PEFR) and cross-shift and cross-week pulmonary function tests (PFTs). Results revealed no dose-response effect of pentamidine exposure on cross-shift and cross-week PFTs. However, declines in cross-shift PEFRs, diffusion capacities, and increased symptom complaints were observed for a subset of the study population. This suggested that outcomes were modulated by host factors (history of hay fever and allergy) as well as exposure doses. Treatment both efficacy in containing fugitive AP aerosol was also corroborated as a means of minimizing worker exposure.

Adult↗
PubMed1989

[Immunologic findings in the newborn infant. I. Studies of cellular immunity].

Based on investigations of 133 healthy full-term newborns in the first 3 days of life parameters of cellular immunity are described. The lymphocyte count of 28.5 +/- 10.9% (mean +/- S.D.) or 4.45 +/- 1.99 Gpt/l respectively coincides with literature values. Estimation of T-lymphocytes (E-rosette method) yields a percentage of 67.5 +/- 10%, which is not different from adults, whereas the absolute number 2.99 +/- 1.42 Gpt/l is markedly higher. Measuring phytohemagglutinin induced lymphocyte transformation one often finds a high spontaneous activity in unstimulated controls. The transformation rate, then, is low. 14 of 129 samples had unstimulated control activities higher than with phytohemagglutinin so that stimulation indices could not be calculated. Fairly good lymphocyte transformation was found in more than a half of all newborns. There is no correlation between the absolute value of stimulation index and the phytohemagglutinin-concentration.

Female↗
PubMed1989

[Immunologic findings in the newborn infant. II. Studies of humoral immunity, reference values of immunologic studies in the newborn infant].

After dealing with cellular immune aspects in the first part of the paper the authors describe in the second part the state of humoral immunity in healthy full-term newborns aged one to three days. The number of complementreceptor lymphocytes was 17.0 +/- 8.9% or 0.75 +/- 0.51 (mean +/- S.D.) respectively, with the EAC-rosette method. The percentage value equalled that of adults but the absolute count is higher. Using the immunodiffusion method IgA was detectable in 4 out of 132 newborns only 8.86 +/- 2.52 g/l (mean +/- S.D.) was measured as an average IgG concentration. With regard to the IgM content the values often exceeded 0.30 g/l in newborns of mothers who had been suffering from pre-eclampsia. Their mean value of 0.35 +/- 0.21 g/l, too, was significantly higher than 0.13 +/- 0.08 in the resting infants. Raised IgM values frequently coincided with high spontaneous transformation activities in lymphocyte cultures. The possible causes are discussed. Complement C3-component was measured on average with 0.78 +/- 0.18 g/l and C4-component with 0.34 +/- 0.11 g/l. When calculating reference values for newborns the results of infants with maternal pre-eclampsia have been omitted.

Complement C3↗
PubMed1985

Model of gas transport during high-frequency ventilation.

We analyze gas exchange during high-frequency ventilation (HFV) by a stochastic model that divides the dead space into N compartments in series where each compartment has a volume equal to tidal volume (V). We then divide each of these compartments into alpha subcompartments in series, where each subcompartment receives a well-mixed concentration from one compartment and passes a well-mixed concentration to another in the direction of flow. The number of subcompartments is chosen on the basis that 1/alpha = (sigma t/-t)2, where -t is mean transit time across a compartment of volume, and sigma t is standard deviation of transit times. If (sigma t/-t)D applies to the transit times of the entire dead space, the magnitude of gas exchange is proportional to (sigma t/-t)D, frequency, and V raised to some power greater than unity in the range where V is close to VD. When V is very small in relation to VD, gas exchange is proportional to (sigma t/-t)2D, frequency, and V raised to a power equal to either one or two depending on whether the flow is turbulent or streamline, respectively. (sigma t/-t)D can be determined by the relation between the concentration of alveolar gas at the air outlet and volume expired as in a Fowler measurement of the volume of the dead space.

Humans↗
PubMed1985

Nitrogen washout and mortality.

We studied the association between different tests of pulmonary function and subsequent mortality. Subjects were drawn from an epidemiology study of chronic obstructive pulmonary disease. Between 1971 and 1976, 2,539 nonpatient adults had tests of forced expiration, diffusing capacity, and single-breath nitrogen washout. By 1981, 115 of those subjects had died, including 3 from known lung disease. In assessing the relationship between lung function and mortality, the following tests of pulmonary function were examined: forced expiratory volume in one second as a percentage of forced vital capacity, forced expiratory volume divided by height cubed, slope of phase III from the single-breath nitrogen test, closing capacity, diffusing capacity for CO, and the ratio of maximal flow at 75% to that at 25% vital capacity. When adjustments for age and smoking were made, slope of phase III was strongly associated with mortality, even more so than tests of forced expiration. There are two possible explanations for this striking relationship between these observed abnormalities of lung function and subsequent overall mortality (which is largely from nonpulmonary disease): the lungs may serve to protect other systems of the body and therefore poor pulmonary function may contribute to a number of diseases leading to death, or lung function may merely reflect existing disorders in other systems of the body, and the observed association between mortality and pulmonary function is a byproduct of nonpulmonary diseases.

Adult↗
PubMed1984

Gas transport during high-frequency ventilation: theoretical model and experimental validation.

We present a theoretical model of gas transport through the dead space during high-frequency ventilation (HFV) with volumes less than dead space volume. The analysis is based on the axial distribution of transit times of gas moving through the dead space. The model predicts that for tidal volumes (V) much less than dead space (VD), gas exchange will be proportional to the product of frequency (f) and V2. If gas transport is analyzed in terms of Fick's law, then the effective diffusion coefficient (Deff) can be shown to be equal to fV2 times a constant, whose value equals the square of the coefficient of dispersion of axial transit times through the dead space (sigma t/t)2. Experimental results in straight tubes fit the predictions of this model quite well. A (sigma t/t) through the entire dead space of about 30% is more than sufficient to account for gas exchange during HFV in physical models or in intact animals. An axial dispersion of this magnitude can be measured directly from a typical Fowler dead space determination in healthy subjects.

Animals↗
PubMed1984

Effect of changes in airway pressure on breathing pattern in conscious dogs.

The effect of brief (400 ms) or sustained (several breaths) application of positive or negative intrapulmonary air pressure was studied in three exercising conscious dogs. Changes in inspiratory duration (TI), expiratory duration (TE) and tidal volume (VT) were measured with the dogs' vagus nerves at body temperature and cooled to a temperature which abolished the Hering-Breuer inflation reflex (7 degrees C). Comparison of these results with those obtained with anaesthetized dogs leads us to suggest that there exists in conscious dogs a reflex inspiratory promoting drive.

Afferent Pathways↗