An outbreak of vancomycin-resistant enterococci associated with major ward refurbishment.
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Cross Infection↗
Biomedical subjects
G Woodrow
Publications and source records attributed to G Woodrow.
A novel technique to demonstrate disturbed appetite profiles in haemodialysis patients.
BACKGROUND: Malnutrition is common among dialysis patients and is associated with an adverse outcome. One cause of this is a persistent reduction in nutrient intake, suggesting an abnormality of appetite regulation. METHODS: We used a novel technique to describe the appetite profile in 46 haemodialysis (HD) patients and 40 healthy controls. The Electronic Appetite Rating System (EARS) employs a palmtop computer to collect hourly ratings of motivation to eat and mood. We collected data on hunger, desire to eat, fullness, and tiredness. HD subjects were monitored on the dialysis day and the interdialytic day. Controls were monitored for 1 or 2 days. RESULTS: Temporal profiles of motivation to eat for the controls were similar on both days. Temporal profiles of motivation to eat for the HD group were lower on the dialysis day. Mean HD scores were not significantly different from controls. Dietary records indicated that dialysis patients consumed less food than controls. CONCLUSIONS: Our data indicate that the EARS can be used to monitor subjective appetite states continuously in a group of HD patients. A HD session reduces hunger and desire to eat. Patients feel more tired after dialysis. This does not correlate with their hunger score, but does correlate with their fullness rating. Nutrient intake is reduced, suggesting a resetting of appetite control for the HD group. The EARS may be useful for intervention studies.
Adult↗
The measurement of total body potassium in patients on peritoneal dialysis.
OBJECTIVES: To assess the validity of measuring total body potassium (TBK) to estimate fat-free mass (FFM) and body cell mass (BCM) in patients on peritoneal dialysis (PD). METHODS: We studied 29 patients on PD (14 men, 15 women) and 30 controls (15 men, 15 women). We calculated TBK by using a whole-body counter to measure 1.46 MeV gamma-ray emissions from naturally occurring 40K. We measured total body water (TBW) by deuterium oxide dilution, and extracellular water (ECW) from bromide dilution. These measurements allowed us to estimate intracellular water (ICW), fat-free mass dilution (FFM(Dilution)), and body cell mass dilution (BCM(Dilution)). RESULTS: The FFM(TBK) in male PD patients (55.7 +/- 7.0 kg) did not differ from that in male controls (57.0 +/- 10.9 kg). The FFM(TBK) in female PD patients (38.4 +/- 6.8 kg) was less than that in female controls (44.7 +/- 4.5, p < 0.01). The FFM(Dilution) did not differ from the FFM(TBK). Correlation of FFM(TBK) and FFM(Dilution) was r = 0.90, p < 0.0001 for all subjects; r = 0.90, p < 0.0001 for PD patients; and r = 0.90, p < 0.0001 for controls. Bland-Altman comparison of FFM(Dilution) with FFM(TBK) in individuals showed bias 0.6 kg, range -8.5 kg to 9.7 kg for the whole group; bias 1.4 kg, range -7.9 kg to 10.7 kg for PD patients; and bias -0.2 kg, range -9.0 kg to 8.6 kg for controls. The BCM(TBK) in male PD patients (30.1 +/- 4.5 kg) did not differ from that in male controls (31.9 +/- 6.2 kg). The BCM(TBK) in female PD patients (19.0 +/- 4.4 kg) was less than that in female controls (23.1 +/- 2.9 kg, p < 0.01). The BCM(Dilution) results did not differ from those for the BCM(TBK). Correlation of BCM(TBK) and BCM(Dilution) was r = 0.90, p < 0.0001 for all subjects; r = 0.87, p < 0.0001 for PD patients; and r = 0.93, p < 0.0001 for controls. Bland-Altman comparison of BCM(Dilution) with BCM(TBK) in individuals showed bias 0.1 kg, range -5.9 kg to 6.1 kg for the whole group; bias 0.0 kg, range -6.9 kg to 6.9 kg for PD patients; and bias 0.1 kg, range -5.0 kg to 5.2 kg for controls. The [K+]ICW did not differ between PD patients and controls (148.0 +/- 25.1 mmol/L vs 148.1 +/- 14.3 mmol/L, p = nonsignificant). CONCLUSIONS: Total body potassium is a valid, noninvasive technique for measuring FFM and BCM in PD patients. In our PD patient group, depletion of FFM and BCM as compared with controls was identified in the women but not in the men.
Body Composition↗
Effect of peritoneal fluid on whole body and segmental multiple frequency bioelectrical impedance in patients on peritoneal dialysis.
OBJECTIVE: We investigated the ability of whole body and segmental multiple frequency bioelectrical impedance (MFBIA) to detect peritoneal fluid in peritoneal dialysis patients. DESIGN: Prospective study. SETTING: Teaching hospital renal unit. SUBJECTS: Patients on regular peritoneal dialysis. INTERVENTIONS: Whole body and segmental MFBIA measurements before and after drainage of peritoneal fluid. RESULTS: Changes estimated by MFBIA in total body water (-0.4 (0.8) litres) and extracellular water (-0.3 (0.3) litres) were much lower than the actual changes (2.0 (0.4) litres), P<0.0001. Derived resistances Recf and Ricf increased significantly for the trunk but not for total body measurements and changes did not correlate with volumes of fluid drained. CONCLUSIONS: MFBIA is limited in its ability to detect intraperitoneal fluid, using both whole body and segmental techniques.
Adult↗
Consistent timing of the post-dialysis blood sample is necessary to prevent undertreatment in single needle dialysis.
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Adult↗
Effects of icodextrin in automated peritoneal dialysis on blood pressure and bioelectrical impedance analysis.
BACKGROUND: Glucose absorption from glucose-based dialysis fluids limits ultrafiltration from the daytime dwell in automated peritoneal dialysis (APD). Icodextrin may allow greater ultrafiltration during the daytime period in APD, enhancing fluid control. METHODS: A 7.5% icodextrin dialysate was compared with a 2. 27% glucose dialysate for the daytime dwell in 14 subjects on APD. Blood pressure, weight and body water compartments estimated by multifrequency bioelectrical impedance (MFBIA) were determined in subjects using 2.27% glucose as the daytime dwell and then repeated 1 month after switching to icodextrin. RESULTS: Icodextrin resulted in symptomatic hypotension requiring reduction of antihypertensive medication in six of the 14 patients. Despite this reduction in treatment, systolic blood pressure fell from 142.4 (23.9) mmHg to 122.9 (17.7) mmHg, P<0.005, and diastolic blood pressure tended to fall from 82.8 (9.8) mmHg to 76.8 (10.1) mmHg, P=0.075. Change in systolic blood pressure significantly correlated with changes in weight (r=0.62, P<0.05) and MFBIA estimates of total body water (TBW) (r=0.56, P<0.05), extracellular water (ECW) (r=0.79, P<0.002), extra/intracellular water ratio (ECW/ICW) (r=0.72, P<0.01) and derived resistances R(ecf) of ECW (r=-0.69, P<0.01) and R(inf) of TBW (r=-0.66, P<0.02). Changes in diastolic blood pressure significantly correlated with changes in ECW (r=0.64, P<0.02) and ECW/ICW ratio (r=0.58, P<0.05), and almost significantly with R(ecf) (r=-0.51, P=0.08) and R(inf) (r=-0.52, P=0.07) estimated by MFBIA, but not with changes in weight or TBW. CONCLUSIONS: Use of icodextrin for the daytime dwell in APD results in improved fluid balance and blood pressure control compared with 2.27% glucose. MFBIA detected clinically important changes in fluid content in these patients.
Adult↗
Biocompatible dialysis membranes do not reduce plasma leptin levels.
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Adult↗
Low thrombogenicity of polyethylene glycol-grafted cellulose membranes does not influence heparin requirements in hemodialysis.
Heparin is the most commonly used anticoagulant for hemodialysis despite potentially serious side effects. Polyethylene glycol-grafted cellulose (PGC) membranes produce less activation of the coagulation cascade than cuprophane membranes. Anecdotally, we found some patients required a surprisingly low level of anticoagulation using these membranes. We compared the anticoagulant requirement of the PGC membrane with that of the cuprophane membrane in this randomized, prospective, crossover study. Sixty-three patients were randomized to treatment using either membrane, and heparin administration was progressively reduced to the lowest dose that prevented visible clotting in excess of that normally encountered. Patients underwent dialysis at this dose for 1 month, after which the heparin requirement and Kt/Vurea (1.162 x ln [urea pre/urea post]) were assessed. This process was then repeated for each patient using the other membrane, and the results were compared. Heparin administration during dialysis was reduced from a mean loading dose of 29.0 +/- 9.4 to 1.5 +/- 3.2 IU/kg for both membranes and a mean maintenance infusion of 14.0 +/- 6.7 to 0.77 +/- 1.6 IU/kg/h for both membranes (both P < 0.0001 v full anticoagulation; no difference between membranes). The Kt/Vurea was not significantly altered. Forty-six patients with PGC and 45 patients with cuprophane membranes underwent dialysis successfully without heparin during dialysis, and the other patients were using considerably reduced doses. Aspirin and warfarin had no effect on the heparin requirement. These results do not support the theory that PGC membranes have a lower anticoagulant requirement than cuprophane membranes; however, they suggest that dialysis can be performed successfully with much smaller anticoagulant doses than are currently in common use.
Anticoagulants↗
Ecstasy-induced renal vasculitis.
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Humans↗
Comparison of icodextrin and glucose solutions for the daytime dwell in automated peritoneal dialysis.
BACKGROUND: The sustained ultrafiltration achieved by icodextrin is more suited for the daytime dwell in automated peritoneal dialysis (APD) than glucose solutions. METHODS: Seventeen patients receiving APD underwent assessment using three different solutions for the daytime dwell: 2.27% glucose, 3.86% glucose and 7.5% icodextrin. Patients were then observed on icodextrin for a 6 month period. RESULTS: Daytime ultrafiltration was greater for 3.86% glucose (median 0.10, IQR 0.01 to 0.321) P<0.01 and icodextrin (median 0.26, IQR 0.14 to 0.361) P<0.001 than 2.27% glucose (median -0.19, IQR -0.54 to -0.081), with 3.86% glucose and icodextrin not being significantly different. Positive ultrafiltration occurred in 3/17 patients with 2.27% glucose, 13/17 patients with 3.86% glucose and 16/17 patients with icodextrin (chi2 P<0.0001). The difference in ultrafiltration of icodextrin and 3.86% glucose correlated with the 4 h dialysate/plasma creatinine ratio in a PET test (r = 0.51, P<0.05). Daytime Kt/V urea was greater for 3.86% glucose (median 0.27, IQR 0.20 to 0.48 per week, P<0.01) and icodextrin (median 0.31, IQR 0.27 to 0.49 per week, P<0.0001) than for 2.27% glucose (median 0.22, IQR 0.15 to 0.38 per week), with the difference between 3.86% glucose and icodextrin not reaching statistical significance (P = 0.06). Daytime creatinine clearance was greater for 3.86% glucose (median 10.2, IQR 6.9 to 13.61/week/1.73 m2, P<0.02) and icodextrin (median 12.1, IQR 9.3 to 15.71/week/1.73 m2, P<0.005) than for 2.27% glucose (median 8.8, IQR 4.9 to 11.91/week/1.73 m2). Daytime creatinine clearance was greater for icodextrin than for 3.86% glucose (P<0.005). The effects of icodextrin were sustained for the 6 month observation period. CONCLUSIONS: Icodextrin produced enhanced ultrafiltration and clearances compared with 2.27% glucose, without the exposure of the peritoneum to hypertonic glucose solutions.
Adult↗
Nightly intermittent peritoneal dialysis prescription and power.
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Humans↗
Comparison of in-vivo body composition using two Lunar dual-energy X-ray absorptiometers.
OBJECTIVE: To compare in-vivo composition analysis between two dual energy X-ray absorptiometers, a DPX and a DPX/L, from the same manufacturer (LUNAR), pre(Study A) and post(Study B) hardware changes on both absorptiometers. DESIGN: Comparison of (1) quality assurance (QA) data: air-counts low (38 keV), air-counts high (70 keV), air-counts ratio, percent spillover, R-delrin; and (2) total body compartments: total body tissue (TBTISS), total body fat (TBF), percent total body fat (%TBF), total body lean (TBLEAN), total body bone mineral content (TBBMC) and total body bone mineral density (TBBMD), between the two absorptiometers. SETTING: Centre for Bone and Body Composition Research, University of Leeds. SUBJECTS: Study A, 14 normal subjects and Study B, a different cohort of 19 normal subjects, were scanned on both machines on the same day. RESULTS: In Study A, large significant differences were observed in the QA parameters between the two machines. The DPX, air-counts low and air-counts high, being 25% and 22% lower than the DPX/L. The Bland Altman method of analysis indicated that the DPX was significantly higher for TBTISS (0.3 kg), %TBF (2%) and TBF ( 1.4 kg) and correspondingly lower for TBLEAN (-1.0 kg). No significant difference was observed in TBBMC. After the hardware changes (Study B) a marked reduction in the differences in QA air-counts was observed. The DPX air-counts low was now 1% higher and air-counts high 8% lower than the DPX/L. The DPX had now only small significant negative differences for %TBF (-0.6%) and TBF (-0.4 kg) and a small significant positive difference for TBLEAN (0.4 kg), compared to the DPX/L. TBBMC difference although slightly increased, was still non-significant. CONCLUSIONS: The closer agreement observed in the QA parameters after the hardware changes was associated with a reduction in the mean differences, 95%CI of the mean differences and limits of agreement of the comparison of body composition analysis from the Lunar machines using the Bland-Altman method. The study indicates that the QA limits set for bone mineral analysis may require more stringent limits for body composition.
Absorptiometry, Photon↗
Increased plasma leptin/fat ratio in patients with chronic renal failure: a cause of malnutrition?
BACKGROUND: Protein-energy malnutrition occurs in patients with chronic renal failure primarily due to loss of appetite. The ob gene protein, leptin, which is secreted by adipocytes, regulates body composition by lowering food intake. We have measured plasma leptin in undialysed and dialysed patients and in controls and the concentrations have been related to body composition, dietary intake, and biochemistry. METHODS: Plasma leptin was measured by radioimmunoassay in 93 individuals in groups of undialysed, peritoneal dialysed, and haemodialysed patients and controls. Body composition was determined by DEXA. RESULTS: Protein-energy malnutrition was evident in non-dialysed and dialysed patients from low lean or fat tissues, plasma albumin and transferrin. A third of the dialysis patients were eating less than prescribed intakes. Leptin relative to total fat mass (ng/ml/kg) was significantly greater for patients than for controls, particularly the dialysed patients. Leptin was highly correlated with total, arm, leg, and all other fat measurements, e.g. r for leptin vsm % total fat was: undialysed 0.88, PD 0.81, HD 0.93, and controls 0.83 (P < 0.0001 for all). Dialysis patients with the highest leptin/fat mass ratio had low protein intakes and significantly lower lean tissue mass. Leptin/fat ratio correlated inversely with dietary intake e.g. with protein intake in g/day and marginally in g/kg of ideal weight/day. Leptin concentration was unrelated to plasma creatinine or residual renal function or to the protein 'nutritional indices', albumin and transferrin. CONCLUSIONS: Our data suggests that leptin is markedly increased in some patients with chronic renal failure. The association of increased leptin with low protein intake and loss of lean tissue is consistent with leptin contributing to malnutrition but a definitive role cannot be substantiated by this study.
Aged↗
The effect of arteriovenous fistulae in haemodialysis patients on whole body and segmental bioelectrical impedance.
BACKGROUND: Bioelectrical impedance (BIA) is a potentially useful method for measuring body water and soft-tissue composition in patients with chronic renal failure. The majority of whole body impedance is derived from the limbs with only a small contribution from the trunk, and thus abnormalities of the limbs could have an exaggerated effect on estimates of total body impedance. METHODS: This study investigated the effect of arteriovenous fistulae in the arm in haemodialysis patients on body composition measurement by whole body BIA. Body composition estimates from measurements on fistula and non-fistula sides of the body were compared and segmental impedance measurements of the arms were also performed. RESULTS: Whole body resistance was markedly lower on the fistula side of the body compared with the nonfistula side at 517.1 (124.3) omega compared with 561.5 (121.2) omega, P < 0.0005. This difference was accounted for by differences in the arm segments. This was attributed to swelling of the fistula arm which had a greater mid-arm circumference at 28.5 (2.1) cm compared with the contralateral side at 27.5 (2.0) cm, P < 0.05. This resulted in greater estimates for total body water from the fistula side at 38.6 (10.0) kg compared with 36.6 (8.6) kg from the non-fistula side, P < 0.05 and fat-free mass at 51.1 (11.8) kg from the fistula side compared with 49.1 (11.2) kg from the non-fistula side, P < 0.005. Estimates of body fat from the fistula side, 13.1 (6.9) kg, were less than the nonfistula side, 15.0 (6.0), P < 0.005. CONCLUSIONS: The presence of arteriovenous fistulae for vascular access in haemodialysis patients may have a significant effect on estimates of body composition by BIA.
Arm↗
Measurement of total body water and urea kinetic modelling in peritoneal dialysis.
Studies of the effect of Kt/V (urea) on prediction of outcome in patients on peritoneal dialysis have shown conflicting results. We performed this study to examine the effects of the measurement of V by varying techniques on the calculation of Kt/V, using body water estimated by deuterium oxide dilution (D2O dilution) as the criterion method for estimation of V. Studies were performed in 20 peritoneal dialysis patients. Kt was calculated from 24-hour dialysate and urine collections and V estimated by D2O dilution, Watson formulae, 58% of body weight, bioelectrical impedance (BIA) and 73% of fat-free mass estimated by DEXA. V was also measured in 35 healthy controls. Hydration, expressed as body water by D2O dilution as a percentage of fat-free mass estimated by DEXA did not differ between peritoneal dialysis patients 71.0 (4.9)% and a healthy control group 71.1 (5.0)%. Mean Kt/V using D2O dilution was 2.14 (0.36). The other techniques resulted in a significantly lower Kt/V; Watson equations 2.01 (0.35), p < 0.005, BIA 1.93 (0.31), p < 0.0001, DEXA 2.06 (0.28), p < 0.05, 58% body weight 1.83 (0.38), p < 0.0001. Limits of agreement of Kt/V by the simpler techniques compared with D2O dilution [mean difference of (other techniques -D2O dilution) as % of mean values +/- 95% limits of agreement] were Watson equation -5.9 +/- 15.3%, BIA -10.1 +/- 15.5%, DEXA -3.4 +/- 13.5% and 58% body weight -9.9 +/- 23.5%. Differences in Kt/V from estimates using D2O dilution were significantly negatively correlated with body fat for 58% body weight (r = -0.80, p < 0.0001) and the Watson formulae (r = -0.49, p < 0.05) but not for BIA or DEXA. We conclude that clinically significant variation in Kt/V may occur due to the estimation of V and may account for the uncertainty of the value of Kt/V as a predictor of outcome in peritoneal dialysis patients. Estimating V by BIA and DEXA did not have any benefit over the Watson formulae in terms of agreement with D2O dilution, though did avoid systematic errors related to body fat. Estimation of V as a fixed proportion of body weight is clearly inferior to the other techniques.
Absorptiometry, Photon↗
Segmental bioelectrical impedance in patients with chronic renal failure.
We studied changes in hydration by whole body and segmental (arm, leg and trunk)bioelectrical impedance analysis (BIN in patients with chronic renal failure (CRF) undergoing haemodialysis and continuous ambulatory peritoneal dialysis (CAPD). Mean (SD) fluid removal by haemodialysis of 1.38 (0.81) kg was overestimated by whole body BIA at 1.83 (1.13) I, P < 0.005. Peritoneal fluid drained from the CAPD patients of 1.88 (0.36) kg was underestimated by whole body BIA at 0.59 (0.35) I, P < 0.0001. Resistance and reactance significantly increased for the whole body and all segments (except trunk reactance) after haemodialysis. Drainage of CAPD fluid resulted in smaller increases in trunk resistance and whole body resistance. The increase in trunk resistance was less in CAPD than haemodialysis patients, even though the volume of fluid drained from the peritoneum in CAPD patients exceeded that removed from the whole body during haemodialysis. We conclude that whole body BIA does not estimate changes in body fluid with sufficient accuracy to be of use in clinical practice. Segmental impedance may be a potentially useful method for investigation of regional changes in body fluid, though is insensitive to changes within the peritoneal cavity.
Journal Article↗
Four-component model of body composition in chronic renal failure comprising dual-energy X-ray absorptiometry and measurement of total body water by deuterium oxide dilution.
1. Assessment of nutrition in patients with chronic renal failure by body composition measurement techniques may be affected by variable hydration. 2. This study aimed to derive a four-component model of body composition (consisting of fat, protein, total body water and body mineral) from a combination of dual-energy X-ray absorptiometry and total body water measured by deuterium oxide dilution, allowing assessment of body protein stores without the effect of variation in hydration. Patients with chronic renal failure on haemodialysis, peritoneal dialysis and conservative treatment and a control group were studied. Patients with chronic renal failure were at an 'ideal' state of hydration on clinical assessment. 3. Hydration was defined by total body water as a percentage of fat-free mass measured by dual-energy X-ray absorptiometry, and no differences were found between chronic renal failure subgroups and control subjects (except in the female undialysed chronic renal failure subgroup). Hydration was significantly correlated with percentage total body fat in the control groups but not in patients with chronic renal failure. 4. Lean tissue measured by dual-energy X-ray absorptiometry was significantly reduced in three of the six chronic renal failure groups compared with control subjects (male and female patients on haemodialysis and female patients on peritoneal dialysis). Protein estimated from the four-component model failed to detect these abnormalities. 5. Lean tissue measured by dual-energy X-ray absorptiometry in normal subjects strongly correlated with fat-free mass measured by total body potassium in normal subjects (male r = 0.91; female r = 0.89, both P < 0.0001). The correlation of protein estimated from the four-component model with fat-free mass measured by total body potassium was far weaker in male control subjects (r = 0.51, P < 0.05) and not significant in female control subjects (r = 0.38, P not significant). In the normal subjects protein estimated from the four-component model showed a much greater variation from protein estimated by total body potassium than did protein estimated simply as 27% of dual-energy X-ray absorptiometry fat-free mass minus total body mineral. 6. Hydration in patients with chronic renal failure in whom fluid balance is believed to be normal on clinical criteria does not differ from that in normal subjects. The combined model of dual-energy X-ray absorptiometry and total body water is not a useful method for the measurement of body protein.
Absorptiometry, Photon↗