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The impact of total body water on breath alcohol calculations. Wien Klin Wochenschr 2020; 132:535-541. [PMID: 32451818 PMCID: PMC7518982 DOI: 10.1007/s00508-020-01663-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 04/12/2020] [Indexed: 11/30/2022]
Abstract
Due to a legislative amendment in Austria to determine breath alcohol (BrAC) instead of blood alcohol (BAC) in connection with traffic offences, many results of blood alcohol calculations were simply converted using distinct conversion factors. In Austria, the transformation of BAC to BrAC was carried out by using a factor of 1:2000, which, however, is commonly known to be too low. Noticing the great demand for a calculation method that is not exclusively based on blood alcohol, a formula for calculating breath alcohol based on blood alcohol was published in 1989, but in which the body surface area (BSA) was considered the most important influencing variable. In order to refine this new method, a liquor intake experiment was conducted combined with measurements of total body water (TBW) as an additional variable, using hand to foot bioelectrical impedance assessment (BIA). The test group comprised 37 men and 40 women to evaluate the accuracy of TBW and BSA as an individual parameter for alcohol concentration. The correlation coefficient of BrAC with TBW was constantly higher than with BSA (maximum = 0.921 at 1 h and 45 min after cessation of alcohol intake). These results are valid for both men and women as well as in a gender independent calculation. Hence, for an accurate back calculation of BrAC adjusted values of eliminations rates had to be found. This study describes mean elimination rates of BrAC for both men (0.065 ± 0.011 mg/L h−1) and women (0.074 ± 0.017 mg/L h−1). As previously shown women displayed a significantly higher elimination rate than men (p = 0.006).
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Konings CJ, Kooman JP, Schonck M, Cox–Reijven PL, Van Kreel B, Gladziwa U, Wirtz J, Gerlag PG, Hoorntje SJ, Wolters J, Heidendal GA, van der Sande FM, Leunissen KM. Assessment of Fluid Status in Peritoneal Dialysis Patients. Perit Dial Int 2020. [DOI: 10.1177/089686080202200607] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Objectives To assess the influence of abnormalities in fluid status and body composition on agreement between multifrequency bioimpedance analysis (MF-BIA), segmental BIA (ΣBIA), the Watson formula, and tracer dilution techniques. Design Cross-sectional. Setting Multicenter. Patients 40 patients (29 males, 11 females) on peritoneal dialysis (PD). Main Outcome Measures Agreement between the various techniques used to assess total body water (TBW) [MF-BIA, deuterium oxide (D2O), and the Watson formula] and extracellular water (ECW) [MF-BIA, bromide dilution (NaBr), and ΣBIA], also in relation to the relative magnitude of the body water compartments [ECW (NaBr):body weight (BW) and TBW (D2O):BW] and body composition (DEXA). Second, the relation between body water compartments with echocardiographic parameters. Results Wide limits of agreement were observed between tracer dilution techniques and MF-BIA [TBW (D2O – MF-BIA) 2.0 ± 3.9 L; ECW (NaBr – MF-BIA) –2.8 ± 3.9 L], which were related to the relative magnitude of the body water compartments: r = 0.70 for ECW and r = 0.40 for TBW. ΣBIA did not improve the agreement [ECW (NaBr – ΣBIA): 3.7 ± 2.9 L]. Also, wide limits of agreement were observed between D2O and the Watson formula (–2.3 ± 3.3 L). The difference between D2O and Watson was related to hydration state and to percentage of fat mass ( r = 0.70 and r = –0.53, p < 0.05). Both ECW and TBW as assessed by BIA and tracer dilution were related to echocardiographic parameters. Conclusion Wide limits of agreement were found between MF-BIA and ΣBIA with dilution methods in PD patients, which were related to hydration state itself. The disagreement between the Watson formula and dilution methods was related to both hydration state and body composition.
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Affiliation(s)
| | | | - Marc Schonck
- University Hospital Maastricht; West Fries Gasthuis Hoorn, Germany
| | | | | | | | - Joris Wirtz
- Sint Laurentius Hospital Roermond University Hospital Maastricht, The Netherlands
| | - Paul G. Gerlag
- Sint Joseph Hospital Veldhoven University Hospital Maastricht, The Netherlands
| | - Steven J. Hoorntje
- Catharina Hospital Eindhoven University Hospital Maastricht, The Netherlands
| | - Johannes Wolters
- Atrium Hospital Heerlen University Hospital Maastricht, The Netherlands
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Tzamaloukas AH, Murata GH, Piraino B, Raj DSC, VanderJagt DJ, Bernardini J, Servilla KS, Sun Y, Glew RH, Oreopoulos DG. Sources of variation in estimates of lean body mass by creatinine kinetics and by methods based on body water or body mass index in patients on continuous peritoneal dialysis. J Ren Nutr 2009; 20:91-100. [PMID: 19853476 DOI: 10.1053/j.jrn.2009.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE We identified factors that account for differences between lean body mass computed from creatinine kinetics (LBM(cr)) and from either body water (LBM(V)) or body mass index (LBM(BMI)) in patients on continuous peritoneal dialysis (CPD). DESIGN We compared the LBM(cr) and LBM(V) or LBM(BMI) in hypothetical subjects and actual CPD patients. PATIENTS We studied 439 CPD patients in Albuquerque, Pittsburgh, and Toronto, with 925 clearance studies. INTERVENTION Creatinine production was estimated using formulas derived in CPD patients. Body water (V) was estimated from anthropometric formulas. We calculated LBM(BMI) from a formula that estimates body composition based on body mass index. In hypothetical subjects, LBM values were calculated by varying the determinants of body composition (gender, diabetic status, age, weight, and height) one at a time, while the other determinants were kept constant. In actual CPD patients, multiple linear regression and logistic regression were used to identify factors associated with differences in the estimates of LBM (LBM(cr)<LBM(V), or LBM(cr)<LBM(BMI)). MAIN OUTCOME MEASURE We sought predictors of the differences LBM(V) - LBM(cr) and LBM(BMI) - LBM(cr). RESULTS Both LBM(V) (regardless of formula used to estimate V) and LBM(BMI) exceeded LBM(cr) in hypothetical subjects with average body compositions. The sources of differences between LBM estimates in this group involved differences in the coefficients assigned to gender, age, height, weight, presence or absence of diabetes, and serum creatinine concentration. In CPD patients, mean LBM(V) or LBM(BMI) exceeded mean LBM(cr) by 6.2 to 6.9 kg. For example, the LBM(V) obtained from one anthropometric formula was 50.4+/-10.4 kg and the LBM(cr) was 44.1+/-13.6 kg (P < .001), whereas among the 925 clearance studies, only 216 (23.3%) had LBM(cr)>LBM(V). The differences in determinants of body composition between groups with high versus low LBM(cr) were similar in hypothetical and actual CPD patients. Multivariate analysis in actual CPD patients identified serum creatinine, height, age, gender, weight, and body mass index as predictors of the differences LBM(V)-LBM(cr) and LBM(BMI)-LBM(cr). CONCLUSIONS Overhydration is not the sole factor accounting for the differences between LBM(cr) and either LBM(V) or LBM(BMI) in CPD patients. These differences also stem from the coefficients assigned to major determinants of body composition by the formulas estimating LBM.
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Affiliation(s)
- Antonios H Tzamaloukas
- Nephrology Section, Raymond G Murphy Veterans Administration Medical Center and University of New Mexico, Albuquerque, New Mexico 87108, USA
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Tzamaloukas AH, Raj DSC, Onime A, Servilla KS, Vanderjagt DJ, Murata GH. The prescription of peritoneal dialysis. Semin Dial 2008; 21:250-7. [PMID: 18248525 DOI: 10.1111/j.1525-139x.2007.00412.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In addition to the maintenance of normal extracellular electrolyte composition, the prescription of continuous peritoneal dialysis (CPD) should address four other specific issues: (i) prevention of uremia by achievement of adequate clearance of azotemic substances, (ii) prevention of progressive expansion of the extracellular volume by adequate peritoneal ultrafiltration, (iii) prevention of loss of residual renal function, and (iv) prevention of deterioration of the peritoneal membrane structure and function. Urea clearance, in the form of Kt/V(Urea), is the index of removal of azotemic substances proposed by current guidelines. The target total (renal plus peritoneal) Kt/V(Urea) is >or=1.7 weekly. To provide the desired peritoneal Kt/V(Urea) (K(p)t/V(Urea)), the prescription of peritoneal dialysis must provide a daily drain volume (Dv) defined by the clearance equations as Dv = V x (K(p)t/V(Urea))/(D/P(Urea)), where V is body water obtained from published anthropometric formulas, K(p)t/V(Urea) = (1.7 - renal Kt/V(Urea))/7 and D/P(Urea) is the dialysate-to-plasma urea concentration ratio at the dwell time prescribed. Computer programs obtain the relevant D/P(Urea) values from formal studies of peritoneal transport. In the absence of these studies (for example, at initiation of CPD), D/P(Urea) values can be obtained from published studies with similar dwell times. Body size, indicated by V, is the major determinant of the K(p)t/V(Urea) limit provided by a given CPD schedule. Other obstacles to achievement of adequate urea clearance are created by poor patient compliance, inaccuracies of the anthropometric formulas estimating V, and mechanical complications of CPD that lead to retention of dialysate in the body. The main requirements for the prescription of adequate ultrafiltration are knowledge of the individual peritoneal transport characteristics, monitoring of urinary volume, and restriction of dietary sodium intake. Excessive dietary sodium intake is the major cause of extracellular volume expansion in CPD. Ideally, sodium intake should be kept at the level of total (peritoneal plus renal) sodium removal. Preventing the loss of residual renal function involves avoidance of nephrotoxic influences in the form of medications, radiocontrast agents, urinary obstruction and infection, and possibly other influences, such an elevated calcium-phosphorus product and anemia. Use of the lowest dialysate dextrose concentration that will allow adequate ultrafiltration is currently the most widespread practical measure of prevention of peritoneal membrane deterioration. Formulation of biocompatible dialysate is a major ongoing research effort and may greatly enhance the success of CPD in the future.
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Affiliation(s)
- Antonios H Tzamaloukas
- Renal Section, Department of Medicine, New Mexico VA Health Care System, 1501 San Pedro, SE, Albuquerque, NM 87108, USA.
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Tzamaloukas AH, Murata GH, Vanderjagt DJ, Glew RH. Estimates of body water, fat-free mass, and body fat in patients on peritoneal dialysis by anthropometric formulas. Kidney Int 2003; 63:1605-17. [PMID: 12675836 DOI: 10.1046/j.1523-1755.2003.00900.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Anthropometric formulas that are used to estimate body water in peritoneal dialysis patients can also be used to estimate fat-free mass and body fat. Evaluation of body composition by the anthropometric formulas rests on two assumptions: (1) fat contains no water, and (2) the water content of the fat-free mass is constant (72%). METHODS We compared estimates of body water, fat-free mass, and body fat by anthropometric formulas to estimates employing dilution of tracer substances to measure body water and standard methods to analyze body composition in studies performed on peritoneal dialysis patients. We also analyzed the potential errors of the estimates of body composition by the formulas. RESULTS Estimates of the average body composition provided by the anthropometric formulas agreed with estimates provided by the standard methods. However, these formulas have the potential of introducing large errors when estimating body composition in individuals differing from the average subject, either because the anthropometric formulas do not account for major determinants of body composition, such as physical exercise, nutrition, and catabolic illness, or because these formulas systematically overestimate body water in subjects who are obese or experiencing volume excess. CONCLUSION Anthropometric formulas currently in existence can provide only approximations of body composition and may be the sources of large errors in evaluating body composition in peritoneal dialysis patients. The potential errors include estimates of body water. These errors may alter the interpretation of urea kinetic studies in certain categories of peritoneal dialysis patients (e.g., obese subjects).
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Affiliation(s)
- Antonios H Tzamaloukas
- Medicine Service, New Mexico Veterans Affairs Health Care System and University of New Mexico School of Medicine, Albuquerque, New Mexico 87108, USA.
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Norberg A, Jones AW, Hahn RG, Gabrielsson JL. Role of variability in explaining ethanol pharmacokinetics: research and forensic applications. Clin Pharmacokinet 2003; 42:1-31. [PMID: 12489977 DOI: 10.2165/00003088-200342010-00001] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Variability in the rate and extent of absorption, distribution and elimination of ethanol has important ramifications in clinical and legal medicine. The speed of absorption of ethanol from the gut depends on time of day, drinking pattern, dosage form, concentration of ethanol in the beverage, and particularly the fed or fasting state of the individual. During the absorption phase, a concentration gradient exists between the stomach, portal vein and the peripheral venous circulation. First-pass metabolism and bioavailability are difficult to assess because of dose-, time- and flow-dependent kinetics. Ethanol is transported by the bloodstream to all parts of the body. The rate of equilibration is governed by the ratio of blood flow to tissue mass. Arterial and venous concentrations differ as a function of time after drinking. Ethanol has low solubility in lipids and does not bind to plasma proteins, so volume of distribution is closely related to the amount of water in the body, contributing to sex- and age-related differences in disposition. The bulk of ethanol ingested (95-98%) is metabolised and the remainder is excreted in breath, urine and sweat. The rate-limiting step in oxidation is conversion of ethanol into acetaldehyde by cytosolic alcohol dehydrogenase (ADH), which has a low Michaelis-Menten constant (Km) of 0.05-0.1 g/L. Moreover, this enzyme displays polymorphism, which accounts for racial and ethnic variations in pharmacokinetics. When a moderate dose is ingested, zero-order elimination operates for a large part of the blood-concentration time course, since ADH quickly becomes saturated. Another ethanol-metabolising enzyme, cytochrome P450 2E1, has a higher Km (0.5-0.8 g/L) and is also inducible, so that the clearance of ethanol is increased in heavy drinkers. Study design influences variability in blood ethanol pharmacokinetics. Oral or intravenous administration, or fed or fasted state, might require different pharmacokinetic models. Recent work supports the need for multicompartment models to describe the disposition of ethanol instead of the traditional one-compartment model with zero-order elimination. Moreover, appropriate statistical analysis is needed to isolate between- and within-subject components of variation. Samples at low blood ethanol concentrations improve the estimation of parameters and reduce variability. Variability in ethanol pharmacokinetics stems from a combination of both genetic and environmental factors, and also from the nonlinear nature of ethanol disposition, experimental design, subject selection strategy and dose dependency. More work is needed to document variability in ethanol pharmacokinetics in real-world situations.
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Affiliation(s)
- Ake Norberg
- Department of Anaesthesia and Intensive Care, Karolinska Institute at Huddinge University Hospital, Huddinge, Sweden
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Smith D, Engel B, Diskin AM, Spanel P, Davies SJ. Comparative measurements of total body water in healthy volunteers by online breath deuterium measurement and other near-subject methods. Am J Clin Nutr 2002; 76:1295-301. [PMID: 12450896 PMCID: PMC5207311 DOI: 10.1093/ajcn/76.6.1295] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND We developed a new near-subject approach, using flowing afterglow-mass spectrometry (FA-MS) and deuterium dilution, which enables the immediate measurement of total body water (TBW) from single exhalations. OBJECTIVES The objectives were to show the efficacy of the new FA-MS method in measuring TBW in healthy subjects and to compare these measurements with values derived from multifrequency bioelectrical impedance analysis, skinfold-thickness (SFT) measurements, and both recent and historical published regression equations. DESIGN After baseline measurement of breath deuterium abundance, 24 healthy subjects ingested 0.3 g D(2)O/kg body wt. A second breath sample was taken after 3 h to measure the increase in deuterium, from which TBW was calculated. Bioelectrical impedance analysis was carried out with a multifrequency analyzer, and SFT was measured by a single trained observer. Methods were compared with the use of Pearson's correlation coefficient and Bland-Altman analyses. RESULTS TBW measures obtained by all methods were highly correlated (r = 0.95-0.98, P < 0.001), especially those between FA-MS, SFT measurement, and recent regression equations. The mean values obtained were within 2% of those published for age-matched control subjects and varied by 1-6% when all methods were compared. Systematic bias was greatest when FA-MS was compared with bioelectrical impedance analysis, which tended to underestimate TBW in smaller, female subjects. No bias related to subject size was observed in a comparison of FA-MS with SFT measurement or with more recent regression equations. CONCLUSIONS FA-MS is a simple and effective new approach to TBW measurement in healthy subjects. The difficulty of using population-derived equations to estimate TBW in individual subjects is emphasized.
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Affiliation(s)
- David Smith
- Centre for Science and Technology in Medicine, School of Postgraduate Medicine, Keele University, Stoke-on-Trent, United Kingdom
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Himmelfarb J, Evanson J, Hakim RM, Freedman S, Shyr Y, Ikizler TA. Urea volume of distribution exceeds total body water in patients with acute renal failure. Kidney Int 2002; 61:317-23. [PMID: 11786114 DOI: 10.1046/j.1523-1755.2002.00118.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND An accurate estimate of volume of distribution of urea (Vurea) is critically important to guide the prescription of therapy and the quantification of delivered dialysis dose in patients with chronic and acute renal failure (ARF). While Vurea has been shown to be substantially the same as total body water (TBW) in other patient populations, this relationship has not been adequately studied in detail in ARF patients. METHODS To evaluate this question, we undertook a systematic study of these parameters in a cohort of 28 patients with ARF to analyze methods of estimating Vurea and TBW using blood-based kinetic data, anthropometric data and bioelectrical impedance analysis (BIA). RESULTS The results show that Vurea estimated by double-pool Kt/V (67.9 +/- 19.2 L) and by equilibrated Kt/V (61.2 +/- 13.6 L) were statistically significantly higher than Vurea determined by single-pool Kt/V (55.3 +/- 12.9 L; difference of 16% and 11%, respectively). Determination of TBW by anthropometric measurements (Watson, 42.5 +/- 7.0 L; Hume-Weyer, 43.6 +/- 7.1 L; Chertow, 46.8 +/- 8.1 L) yielded significantly lower measures compared to TBW determined by physiological formulae and by BIA (51.1 +/- 11.6 L and 51.1 +/- 13.3 L, respectively). Most importantly, all measures of Vurea by blood-based kinetics exceeded TBW measurements by any method (7% to 50% difference). CONCLUSION Our results suggest that in terms of useful guidelines to prescribe a specific dose of dialysis in patients with acute renal failure, estimates of TBW cannot be used as a surrogate for Vurea in determining dialysis adequacy.
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Sherman RA. Briefly Noted. Semin Dial 2000. [DOI: 10.1046/j.1525-139x.1999.t01-5-00002.x-i8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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