Effect of Carboxyhemoglobin on the Single Breath Diffusing Capacity: Derivation of an Empirical Correction Factor

Respiration ◽  
1979 ◽  
Vol 37 (4) ◽  
pp. 185-191 ◽  
Author(s):  
Zabi Mohsenifar ◽  
Donald P. Tashkin
Keyword(s):  
Correction Factor ◽  
Diffusing Capacity ◽  
Single Breath ◽  
Empirical Correction ◽  
Empirical Correction Factor

A Review of Slip Factors for Centrifugal Impellers

1967 ◽  
Vol 89 (4) ◽  
pp. 558-566 ◽  
Author(s):  
F. J. Wiesner
Keyword(s):  
Test Data ◽  
Correction Factor ◽  
Classical Method ◽  
Radius Ratio ◽  
Empirical Expression ◽  
General Review ◽  
Empirical Correction ◽  
Slip Factor ◽  
Empirical Correction Factor

This paper contains a general review of the various methods which have been proposed for the estimation of basic slip factors for centrifugal impellers. As a result of this study, it is concluded that the classical method proposed by Busemann in 1929 is still the most generally applicable prediction for the basic slip factor of centrifugal impellers. The paper then presents a very simple empirical expression, which fits the Busemann results extremely well over the whole range of practical blade angles and number of blades up to a limiting inlet-to-outlet radius ratio for the impeller. An empirical correction factor is also proposed for conditions which exceed this limiting radius ratio. Tabular comparisons of slip factors, with test data (where available), are given for over 60 pump and compressor impellers which have been cited previously in the literature, and the author has added data for several more compressor stages from his own experience.

RE-EVALUATION OF THE CORRECTION FACTOR FOR ETHANOL IN THE CALCULATION OF THE OSMOLAL GAP

2009 ◽  
Vol 32 (6S) ◽  
pp. 5
Author(s):  
V Fung ◽  
M Pudek ◽  
F Rosenberg ◽  
D Holmes
Keyword(s):  
Correction Factor ◽  
Freezing Point ◽  
Laboratory Data ◽  
Plasma Osmolality ◽  
High Volume ◽  
Plasma Sodium ◽  
Correction Factors ◽  
Empirical Correction ◽  
Empirical Correction Factor ◽  
Osmolal Gap

Background/objectives: It is well-known that ethanol (EtOH) demonstrates non-ideal solute behaviour in plasma. This is reflected by its larger than expected contribution to the plasma osmolality. Published multiplicative correction factors for the EtOH contribution range from 1.20 to 1.25. The objective of this study is to determine an optimal correction factor specific to the instrumentation at Vancouver General (VGH) and St. Paul's (SPH) Hospitals. Methods: Laboratory data from patients presenting to the two respective emergency department between August 01, 2007 and November 30, 2008 were extracted from the Sunset database. Plasma sodium, urea, glucose, and EtOH were measured using the two high-volume chemistry analyzers employed at the sites: the Siemens (previously Dade) RXL (VGH) and the Siemens (previously Bayer) Advia 1650 (SPH). Plasma osmolality was measured by freezing-point depression and calculated (excluding the EtOH contribution) using the following standard formula (in SI units): 2 [Na] + [Urea] + [Glucose]. Patients without EtOH data or who had undetectable EtOH were excluded as were patients with methanol or ethylene glycol present. Standard regression statistics were employed. Results: Twelve hundred and fifty-three patient samples (n=823 from SPH and n=430 from VGH) were included. Empirical correction factor m, satisfying, Osmol gap (mmol/kg) =m[EtOH] (mmol/L) was consistently found to be 1.15 for VGH, SPH and both combined. Conclusions: The correction factor of 1.15 for ethanol from the current study appears to be more representative and reliable. Further studies to evaluate its validity in other hospital sites as well as its utility in screening patients with known toxic alcohol ingestion will be warranted.

The effect of conductive ventilation heterogeneity on diffusing capacity measurement

2008 ◽  
Vol 104 (4) ◽  
pp. 1094-1100 ◽  
Author(s):  
Sylvia Verbanck ◽  
Daniel Schuermans ◽  
Sophie Van Malderen ◽  
Walter Vincken ◽  
Bruce Thompson
Keyword(s):  
Carbon Monoxide ◽  
Vital Capacity ◽  
Experimental Situation ◽  
Normal Subjects ◽  
Diffusing Capacity ◽  
Capacity Measurement ◽  
Alveolar Volume ◽  
Estimation Errors ◽  
Single Breath ◽  
Ventilation Heterogeneity

It has long been assumed that the ventilation heterogeneity associated with lung disease could, in itself, affect the measurement of carbon monoxide transfer factor. The aim of this study was to investigate the potential estimation errors of carbon monoxide diffusing capacity (DlCO) measurement that are specifically due to conductive ventilation heterogeneity, i.e., due to a combination of ventilation heterogeneity and flow asynchrony between lung units larger than acini. We induced conductive airway ventilation heterogeneity in 35 never-smoker normal subjects by histamine provocation and related the resulting changes in conductive ventilation heterogeneity (derived from the multiple-breath washout test) to corresponding changes in diffusing capacity, alveolar volume, and inspired vital capacity (derived from the single-breath DlCO method). Average conductive ventilation heterogeneity doubled ( P < 0.001), whereas DlCO decreased by 6% ( P < 0.001), with no correlation between individual data ( P > 0.1). Average inspired vital capacity and alveolar volume both decreased significantly by, respectively, 6 and 3%, and the individual changes in alveolar volume and in conductive ventilation heterogeneity were correlated ( r = −0.46; P = 0.006). These findings can be brought in agreement with recent modeling work, where specific ventilation heterogeneity resulting from different distributions of either inspired volume or end-expiratory lung volume have been shown to affect DlCO estimation errors in opposite ways. Even in the presence of flow asynchrony, these errors appear to largely cancel out in our experimental situation of histamine-induced conductive ventilation heterogeneity. Finally, we also predicted which alternative combination of specific ventilation heterogeneity and flow asynchrony could affect DlCO estimate in a more substantial fashion in diseased lungs, irrespective of any diffusion-dependent effects.

Dynamic measurements of CO diffusing capacity using discrete samples of alveolar gas

1983 ◽  
Vol 54 (1) ◽  
pp. 73-79 ◽  
Author(s):  
B. L. Graham ◽  
J. T. Mink ◽  
D. J. Cotton
Keyword(s):  
Response Time ◽  
Normal Subjects ◽  
Diffusing Capacity ◽  
Dynamic Measurements ◽  
Signal Filtering ◽  
Single Breath ◽  
Discrete Sample ◽  
Yield Information ◽  
Co Concentration ◽  
Sample Method

It has been shown that measurements of the diffusing capacity of the lung for CO made during a slow exhalation [DLCO(exhaled)] yield information about the distribution of the diffusing capacity in the lung that is not available from the commonly measured single-breath diffusing capacity [DLCO(SB)]. Current techniques of measuring DLCO(exhaled) require the use of a rapid-responding (less than 240 ms, 10–90%) CO meter to measure the CO concentration in the exhaled gas continuously during exhalation. DLCO(exhaled) is then calculated using two sample points in the CO signal. Because DLCO(exhaled) calculations are highly affected by small amounts of noise in the CO signal, filtering techniques have been used to reduce noise. However, these techniques reduce the response time of the system and may introduce other errors into the signal. We have developed an alternate technique in which DLCO(exhaled) can be calculated using the concentration of CO in large discrete samples of the exhaled gas, thus eliminating the requirement of a rapid response time in the CO analyzer. We show theoretically that this method is as accurate as other DLCO(exhaled) methods but is less affected by noise. These findings are verified in comparisons of the discrete-sample method of calculating DLCO(exhaled) to point-sample methods in normal subjects, patients with emphysema, and patients with asthma.

Single Breath Carbon Monoxide Diffusing Capacity

1988 ◽  
Vol 137 (5) ◽  
pp. 1244-1244
Author(s):  
Edith Rosenberg ◽  
Margaret R. Becklake
Keyword(s):  
Carbon Monoxide ◽  
Diffusing Capacity ◽  
Single Breath

Lack of late toxicity in patients treated with cisplatin-containing combination chemotherapy for metastatic testicular cancer.

1990 ◽  
Vol 8 (1) ◽  
pp. 21-26 ◽  
Author(s):  
M Boyer ◽  
D Raghavan ◽  
P J Harris ◽  
J Lietch ◽  
A Bleasel ◽  
...  
Keyword(s):  
Testicular Cancer ◽  
Combination Chemotherapy ◽  
Late Toxicity ◽  
Smoking History ◽  
Diffusing Capacity ◽  
Peripheral Nerve Damage ◽  
Single Breath ◽  
Advanced Testicular Cancer

To date, the prevalence and nature of the late toxicity of cisplatin-based combination chemotherapy for advanced testicular cancer has been poorly documented. Thirty men with a median age of 35 years (range, 23 to 63), who had undergone such treatment were assessed with detailed investigation to determine the type and frequency of chronic toxicity. The median follow-up from the time of commencement of chemotherapy was 75 months (range, 48 to 126). The most common late toxic effects were high tone hearing loss in 23 men (77%) and electrophysiological evidence of peripheral nerve damage in 15 (50%). Both the hearing and nerve abnormalities were predominantly asymptomatic. In addition, elevation of serum cholesterol, noted in 20 patients (67%), was significant (P = .014) when compared with a control population. Hyperuricemia was present in nine patients (30%). Only one patient, with other risk factors (smoking, family history), had evidence of ischaemic heart disease while 20% (all with a smoking history) had a diminished single breath diffusing capacity for carbon monoxide (DLCO). Cisplatin-based chemotherapy is relatively free of major long-term side effects and should not be withheld for fear of late toxicity.

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