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K-D Schuster

Publications and source records attributed to K-D Schuster.

6 recordsLinked to original sources
PubMed2006

Model analysis on alveolar-capillary O2 equilibration during exercise.

The present article was aimed at determining the alveolar-capillary PO2 difference (deltaP(AcO2)) during exercise. The working hypothesis was that values of the pulmonary NO diffusing capacity can be used to calculate (deltaP(AcO2)) data on the basis of well-known laws of pulmonary gas exchange. For this purpose, we analysed the pertinent data of three studies performed on 35 healthy, non-athletic non-smokers of similar age at seven different exercise intensities. Calculated mean values of alveolar-capillary PO2 difference aggravated from deltaP(AcO2) at rest to (deltaP(AcO2))=18 mmHg at a performance capacity amounting to 90% of the maximum level. Regression analysis revealed (deltaP(AcO2))=0.31* (V O2/V O2 max)2 at a very high significance level (n=7, r=0.999, P<0.0000082). Due to the non-linear increase of (deltaP(AcO2)) with inclining O(2) consumption, our model analysis confirms the opinion that pulmonary diffusion decreasingly determines maximal aerobic power.

Exercise↗
PubMed2005

Determination of alveolar-capillary O2 partial pressure gradient by using 15NO.

We propose an approach for determining the alveolar-mean capillary oxygen (O(2)) partial pressure gradient to evaluate the efficiency of O(2) equilibration between alveolar space and pulmonary capillary blood. For this purpose, measurements of the pulmonary [(15)N]nitric oxide diffusing capacity are to be interpolated into the recording of O(2) consumption. We expect the O(2) partial pressure gradient amounting to 3.3 mmHg for breathing room air at rest, a third of that commonly given. The simplicity of our method allows its application to children or even artificially ventilated patients. Therefore, it will enable a new insight into pulmonary O(2) equilibration.

Humans↗
PubMed2005

Real-time detection of nitric oxide isotopes in lung function tests.

In lung function tests, the determination of the pulmonary diffusing capacity (D) using the single-breath method is a commonly applied technique. The calculation of D is performed on the basis of accurate measurements of indicator gas concentrations. In this chapter, we demonstrate the appropriateness of the stable nitric oxide (NO) isotopes 14NO and 15NO in revealing reliable data of D. We performed studies on animals (14NO) by using respiratory mass spectrometry (M3) and on humans (15NO) by applying laser magnetic resonance spectroscopy (LMRS). The equipment was characterized by sufficient detection limits of 70 parts/billion at [14NO] = 0.001% (M3) and 40 parts/billion at [15NO] = 0.002 % (LMRS), respectively. Lastly, we were able to show that D-values for 14NO indeed reveal the entire diffusive properties of the alveolar-capillary membrane and that 15NO is a useful indicator gas for reflecting disturbances of pulmonary gas exchange.

Animals↗
PubMed2004

Pulmonary 15NO uptake in interstitial lung disease.

Because lung nitric oxide (NO) diffusing capacity (DL) represents alveolar-capillary gas diffusion, we queried as to whether disturbances of pulmonary gas exchange in interstitial lung disease (ILD) are appropriately reflected by using NO. In this pilot study, we applied the (15)N-labeled stable isotope (15)NO (relative abundance 0.37% of total NO) in order to ignore the endogenous NO production. In 10 ILD-outpatients, we measured DL (15)NO by performing the single-breath method. Lung function parameters as well as arterial oxygen partial pressure (PaO(2)) were also tested. Values of DL (15)NO ranged within 50-151 ml (15)NO/(mmHg min). Ratios of DL (15)NO/reference were between 43 and 108% of predicted data as taken from our previous work on healthy volunteers [Eur. J. Physiol. 446 (2003) 256]. We found a significant reduction of DL (15)NO/reference in five patients. Additionally, values of PaO(2) were significantly correlated to ratios of DL (15)NO/reference (adjusted R2 +/-SEE=0.407+/-8.051). In conclusion, (15)NO represents an appropriate indicator gas for reflecting an ILD-induced impairment of alveolar-capillary gas exchange.

Adult↗
PubMed2003

Pulmonary 15NO uptake in man.

Nitric oxide (NO) is commonly thought to reveal more precise values of pulmonary gas uptake through alveolar-capillary membranes (DL) than the normally used carbon monoxide (CO). Since such measurements are influenced by a significant endogenous NO delivery within human airways, we propose the use of the naturally occurring (15)N-labelled stable nitric oxide isotope (15)NO. It occurs with a relative abundance of 0.37% of the dominating isotope (14)NO. Therefore, the endogenous (15)NO production can be neglected. In the present pilot study we demonstrate the workability of (15)NO in determining DL in healthy individuals. In seven female and 15 male volunteers, averaged values of DL increase with increasing mean alveolar volume as well as individual body height ( P=0.000001). Due to the very high significance level obtained from the multiple regression analysis, we conclude that the application of (15)NO establishes a novel approach to calculate standard values of DL. Such calculations can be employed to predict a reference for patients who suffer from pulmonary diffusion limitation.

Adolescent↗