Cutaneous Mycobacterium haemophilum infection in a kidney transplant recipient after acupuncture treatment.

Mycobacterium haemophilum is a slow-growing nontuberculous mycobacterium that can cause disease in both immunocompetent and immunocompromised patients. The most common clinical presentations of infection are the appearance of suppurative and ulcerated skin nodules. For the diagnosis, samples collected from suspected cases must be processed under the appropriate conditions, because M. haemophilum requires lower incubation temperatures and iron supplementation in order to grow in culture. In this case report, we describe the occurrence of skin lesions in a kidney transplant recipient, caused by M. haemophilum, associated with acupuncture treatment. The diagnosis was established by direct smear and culture of material aspirated from cutaneous lesions. Species identification was achieved by characterization of the growth requirements and by partial sequencing of the hsp65 gene. The patient was successfully treated with clarithromycin and ciprofloxacin for 12 months. Considering that the number of patients receiving acupuncture treatment is widely increasing, the implications of this potential complication should be recognized, particularly in immunosuppressed patients.

Influence of single-nucleotide polymorphisms on C-reactive protein levels in chronic kidney disease before and after kidney transplantation.

INTRODUCTION: We sought to evaluate 2 single-nucleotide polymorphisms (SNPs) in the C-reactive protein (CRP) gene promoter region for their effects on CRP levels in chronic kidney disease (CKD) patients before and after a successful kidney transplantation. METHODS: Fifty CKD patients were evaluated before and at the first and second years after the graft. Two SNPs were studied, a bi-allelic (G-->A) at the -409 and a tri-allelic (C-->T-->A) variation at the -390 position in the CRP gene. RESULTS: All patients presented the -409GG genotype. At the -390 position, the "A" allele was not found; there were 15 "CC" patients, 11 "TT" patients, and 24 "CT" patients. CRP levels were different among patients with various genotypes (P < .019). Also the presence of the allele "T" was sufficient to determine differences in CRP levels both in pretransplantation (P = .045) and at 1 year posttransplantation (P = .011), but not at the second year (P = .448). CONCLUSION: SNPs at the -390 position of the CRP gene promoter region influence CRP basal levels in such a way that the "C" allele correlated with the lowest and the "T" with the highest. We did not observe this influence in our patients at the second year posttransplantation.

Conversion to sirolimus in kidney-pancreas and pancreas transplantation.

Reports on the use of sirolimus (SRL) in pancreas transplantation are still limited. The aim of this study was to evaluate the outcome of SRL conversion in pancreas transplant patients. Among 247 patients undergoing simultaneous kidney-pancreas or solitary pancreas transplantation, 33 (13%) were converted to SRL. The reasons for conversion were calcineurin inhibitors (CNI) nephrotoxicity (n = 24; 73%), severe neurotoxicity owing to CNI (n = 1; 3%), severe and/or recurrent acute rejection episodes (n = 7; 21%), gastrointestinal (GI) side effects of mycophenolate mofetil (MMF; n = 5; 15%), and hyperglycemia (n = 4; 12%). Before conversion, all patients were maintained on a CNI, MMF, and low-dose steroids. They were gradually converted to SRL associated with either CNI or MMF withdrawal. Sixty-three percent (n = 15) of patients who were converted owing to CNI nephrotoxicity, showed stable or improved renal function. At 12 months after conversion, serum creatinine levels were significantly decreased in this group (2.2 +/- 0.5 vs 1.6 +/- 0.3 mg/dL; P = .001) and C-peptide values increased (2.9 +/- 1.1.1 vs 3.1 +/- 1.3 nmol/L; P = .018). The only patient with leucoencephalopathy showed improved neurologic status after SRL conversion. All patients converted to SRL because of GI side effects of MMF showed improvements, and none of those converted because of hyperglycemia experienced improvement. There were no episodes of acute rejection after conversion. We concluded that conversion to SRL in pancreas transplantation should be considered an important alternative strategy, particularly for CNI nephrotoxicity and neurotoxicity, and in cases of severe diarrhea due to MMF.

[Latin-American Dialysis and Kidney Transplantation Registry: data on the treatment of end-stage renal disease in Latin America]. / Registro latino-americano di dialisi e trapianto: dati relativi al trattamento dell'insufficienza renale cronica terminale nell'America Latina.

Latin America, a region composed of a series of neighboring countries that share their history, Latin ancestry and language (Spanish or Portuguese), includes Mexico, Central America, the Spanish Caribbean islands, and South America. The Latin-American Dialysis and Kidney Transplantation Registry, which has been operative since 1991, collects data from 20 countries (Argentina, Brazil, Bolivia, Chile, Colombia, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay, Peru, Puerto Rico, Dominican Republic, Venezuela and Uruguay), where 97% of Latin Americans live. The prevalence of renal replacement therapy (RRT) has increased from 119 patients per million (pmp) in 1991 to 478.2 in 2005 (147,158 patients [57%] on chronic hemodialysis, 58,251 [23%] on peritoneal dialysis and 52,565 [20%] living with a functioning kidney graft). The incidence rate also increased from 27.8 pmp in 1992 to 167 in 2005. The increment in prevalence and incidence occurred in all Latin- American countries. The transplantation rate increased from 3,7 pmp in 1987 to 15 pmp in 2005 (7,968 kidney transplants performed this year, the cumulative number being 98,415). Access to RRT was available for every patient diagnosed with end-stage renal disease only in Argentina, Brazil, Chile, Cuba, Puerto Rico, Venezuela and Uruguay. In Latin America, the incidence and prevalence of RRT increased year by year. Only in some countries is access to RRT available to 100% of diagnosed patients. Detection and prevention programs for chronic kidney disease are needed in the region. Meanwhile, access to RRT has to be improved for everybody who needs it.

No induction versus anti-IL2R induction therapy in simultaneous kidney pancreas transplantation: a comparative analysis.

UNLABELLED: The optimal immunosuppressive regimen for simultaneous kidney pancreas transplantation (SKPT) is still not established. We conducted a study to compare the safety and efficacy of no induction versus anti-IL-2 receptor induction protocols in SKPT recipients receiving the same maintenance regimen. METHODS: Sixty-three SKPT recipients were divided into two groups: no induction group (n = 42) and anti-IL-2 receptor induction group (n = 21). All patients were maintained on tacrolimus, mycophenolate mofetil, and prednisone. Primary endpoints were 1-year acute rejection incidence and patient and graft survivals. RESULTS: Demographic characteristics were similar between the groups. Acute rejection incidence at 1 year was equal in both groups (28.6%). Kidney and pancreas allograft survival in the no induction group were 78.6% and 76.2%, and in the anti-IL-2R induction group, 81% and 71.4%, respectively (P = NS). Patient survival was also similar: 83.3% in the no induction versus 85.7% in the anti-IL-2R induction group. Deaths due to sepsis were higher in the anti-IL-2R induction group, albeit not significantly. CONCLUSION: The use of a no-induction protocol in SKPT is safe and effective immunosuppression that also reduces transplantation costs.

Nephrology in Latin America, with special emphasis on Brazil.

Latin America constitutes a complex universe that shows extreme variation regarding socioeconomic and human development. Brazil is the largest and most populous Latin American country, and combines characteristics encountered in developed countries with problems typically associated with the poorest regions of the world. These disparities condition the profile of renal disease in Brazil, with glomerulonephritis still the leading cause of ESRD. Little is known about the epidemiology of renal disease in the Brazilian (or Latin American) native population, which is numerous in some Central and South American countries, but constitute a very small minority in Brazil. However, interesting information has been obtained from the Yanomamis, a tribe living in Northern Brazil and Southern Venezuela. Hypertension is virtually absent among these people, who ingest very little sodium, lending strong support to the concept that sodium retention, a "civilization" factor, plays a role in the pathogenesis of arterial hypertension. Despite Brazil's striking socioeconomic disparities, access to RRT is in principle accessible to all those in need of it. The dialysis units have been modernized in recent years, whereas the Government covers most expenses related to RRT. However, the prevalence of RRT in Brazil is currently approximately 320 per million population, less than one third as high as in the US, suggesting that ESRD may be underdiagnosed in the country. Much effort is still needed to limit the prevalence of renal disease and to improve the quality and the reach of RRT in Brazil and in Latin America.

Measurement of blood urea concentration during haemodialysis is not an accurate method to determine equilibrated post-dialysis urea concentration.

BACKGROUND: The double-pool urea kinetic model requires the measurement of the blood urea concentrations 30 min after haemodialysis (C(t+30)) to calculate equilibrated Kt/V. However, it has been suggested that urea concentrations 30 min before the end of dialysis (C(t-30)) may be representative of C(t+30). The aim of this study was to validate this suggestion. METHODS: Twenty-two patients underwent haemodialysis for 180, 210, and 240 min. For each patient in each dialysis session, urea exponential decay curve was calculated. Because we measured C(t+30), we calculated the time (T(c)) before the end of dialysis that blood urea concentrations would be the same as C(t+30). In an additional 33 patients, we measured blood urea concentrations at T(c) and in C(t+30). RESULTS: We found that C(t-30) was significantly lower than C(t+30) independent of the duration of dialysis. However, there was a significant correlation between Kt/V(t-30) and Kt/V(t+30). The T(c) was 45 min before the end of dialysis. In the additional 33 patients, C(t-45) and C(t+30) were 54+/-17 and 52+/-17 mg/dl (NS), and Kt/V(t-45) and Kt/V(t+30) were 1.27+/-0.21 and 1.29+/-0.18 (NS), respectively. There were significant correlations between C(t-45) and C(t+30) (r=0.96; P<0.001), and between Kt/V(t-45) and Kt/V(t+30) (r=0.82; P<0.001). However, when measurements were analysed individually, 48% of the data points from C(t-45) vs C(t+30), and 42% of the data points from Kt/V(t-45) vs Kt/V(t+30) fell out of the 95% confidence interval of regression line. CONCLUSIONS: Although C(t-45) is useful to estimate Kt/V when assessing mean values, it is not suitable when assessing patients individually. This study demonstrates that the best method to calculate equilibrated Kt/V was a blood sample for urea concentrations 30 min after haemodialysis.

Reciprocal influences between ambulatorial peritoneal dialysis and pulmonary function.

The aim of this study was to verify if dialysis solution volumes used in patients on continuous ambulatory peritoneal dialysis (CAPD) interfere with pulmonary function and if the pulmonary volumes interfere with the lymphatic absorption of the peritoneal cavity. We submitted 10 CAPD patients with a mean age of 48 +/- 18 years and on CAPD for 35 +/- 27 months to the following evaluations: first, measurement of the lymphatic absorption from the peritoneal cavity; second, measurement of the hydrostatic intraperitoneal pressure; and third, expirometry with the peritoneal cavity full of dialysis solution and empty. There were no differences between the expirometry results obtained with the peritoneal cavity full and empty of dialysis solution, and the results were in accordance with the prediction for this population. The values did not correlate with the peritoneal lymphatic absorption of the peritoneal cavity. The cumulative lymphatic absorption of the peritoneal cavity after 4 h dialysis solution permanence was 197 +/- 93 ml, and the hydrostatic intraperitoneal pressure was 13.9 +/- 2.8 column centimeters of water. Neither of these correlated with pulmonary volumes. In conclusion, CAPD did not interfere with the pulmonary function, nor did the pulmonary function influence the lymphatic absorption of the peritoneal cavity of these patients.

Outcome of acute renal failure associated with cardiac surgery in infants.

OBJECTIVE: To analyze the impact of acute renal failure (ARF) on the evolution of infants undergoing cardiac surgery. METHODS: We assessed 15 infants undergoing cardiac surgery who developed (ARF). Their demographic, clinical and surgical data, and evolution were analyzed. RESULTS: Their mean age was 4.4+/-4.0 months (8 days to 24 months). Twelve infants were males, and 4 patients already had ARF at surgery. The primary cause of ARF was immediate acute cardiac dysfunction in 10 infants, cardiac dysfunction associated with sepsis in 2 infants, and isolated sepsis in 3 infants. All children depended on mechanical ventilation during their postoperative period, 14 infants used vasoactive drugs, and 11 had an infectious process associated with ARF. Thirteen infants required dialytic treatment. Eleven infants developed oluguric ARF, and all had to undergo peritoneal dialysis; of the 4 patients with non-oliguric, 2 required dialysis, the main indication being hypervolemia. Of these 13 dialyzed infants, 4 died in the first 24 hours because of the severity of the underlying cardiac disease (mean urea level of 49+/-20 mg/dl). The mortality rate for the entire group was 60%, and it was higher among the patients with oliguria ARF (73% vs 25%, p<0. 001). The cause of death was acute cardiac dysfunction in 6 infants (early type-1 ARF) and sepsis in the 3 remaining infants (late type-2 ARF). CONCLUSION: The mortality rate of ARF associated with cardiac surgery in infants was hight, being higher among children with oliguria; peritoneal dialysis was indicated due to clinically uncontrolled hypervolemia and not to the uremic hypercatabolic state.

Effect of dialyser biocompatibility on recovery from acute renal failure after cadaver renal transplantation.

BACKGROUND: It has been reported that patients with acute renal failure (ARF) requiring haemodialysis show an improved recovery of renal function when the dialysis treatment is performed using a biocompatible membrane rather than a bioincompatible membrane. However, most recent published human trials have not been able to confirm these findings. METHOD: Over a 2-year period, we prospectively studied 53 patients with ARF after cadaver renal transplantation who required haemodialysis and randomized them into two treatment groups. One group underwent dialysis with a cuprophane membrane and the other group underwent haemodialysis with a more biocompatible membrane, polysulfone. All patients received an immunosuppressive regimen which included azathioprine, prednisone and cyclosporine. RESULTS: There was no difference by patient characteristics or immunosuppressive regimen before acute tubular necrosis (ATN) recovery. In both groups the number of haemodialysis sessions required prior to the recovery of renal function (6.57+/-2.79 vs 6.05+/-2.40), the number of oliguric days (16.25+/-5.14 vs 14.40+/-4.67) and the number of hospital days (33.38+/-12.85 vs 30.10+/-11.00), were not statistically different. There was also no difference in long-term allograft outcome. CONCLUSION: Our data demonstrate that the use of a more biocompatible membrane had no influence on the recovery from acute renal failure after renal transplantation.

Renal transplantation in systemic lupus erythematosus. A case control study of 45 patients.

BACKGROUND: Outcome and the issue of recurrence of disease in systemic lupus erythematosus (SLE) renal transplant recipients is still a matter of controversy. There is a lack of comparative studies with non-SLE patients. The aim of this paper is to compare renal transplantation in lupus patients with a similar matched non-SLE group. METHODS: Forty-five patients with systemic lupus erythematosus subjected to 48 kidney transplants were studied. For comparative purposes, a case-control population was selected, matched for gender, race, type of donor, age, and time of transplantation. Patients with non-glomerulonephritis diseases were excluded. RESULTS: No differences in acute episodes of rejection, causes of kidney loss or patient death were observed. General as well as infectious complications were similar. Pregnancy rates and outcomes were similar with no deleterious effect on patients or grafts. Actuarial 1- and 5-year patient survivals (97.7 and 91.1% for SLE and 95.4 and 87% for controls, respectively) and graft survivals (93.1 and 80.7% for SLE and 88.8 and 70.2% for controls, respectively) were similar. Long-term renal function expressed by serum creatinine was the same. No differences in immunosuppressive drug (azathioprine, prednisone, and cyclosporin) requirements were found. Clinical SLE recurrence was suspected only once (a patient with thrombocytopenia, hypocomplementaemia with low complement levels and positive antiplatelet antibodies). Two SLE patients showed mesangial proliferative glomerulonephritis compatible with recurrence. Both grafts were lost. Two further patients showed membranous glomerulonephritis with an immunofluorescence pattern compatible with recurrence. A fifth patient had necrotizing arteritis which recovered after treatment with cyclophosphamide and another patient showed focal and segmental glomerulosclerosis. Histology of biopsies from five patients in the control group showed signs compatible with recurrence of focal and segmental glomerulosclerosis and membranous glomerulonephritis. There was a wide variation in serum levels of antinuclear antibodies. A wide variation in complement levels was also observed, but with a tendency towards low C4 levels. CONCLUSIONS: The safety of renal transplantation in SLE patients is equivalent to a matched case-control group with a similar rate of recurrence of disease.

Pregnancy in women on chronic dialysis. A single-center experience with 17 cases.

Successful pregnancy outcome is an uncommon occurrence in women requiring chronic dialytic treatment, and the most adequate dialysis therapy in the management of these pregnant patients has not been established. During the period 1988-1995, we studied the outcome of 17 pregnancies in dialyzed females, with an average age of 28.2 +/- 5.9 years (range: 18-38 years). Seven women had adequate urine volume (>800 ml/24 h). Five patients started dialysis after conception and the remaining 12 pregnancies were diagnosed after 6-72 months on dialysis. Fourteen women were maintained on hemodialysis (HD) and 3 on continuous ambulatory peritoneal dialysis (CAPD). The HD schedule was increased to 3 h 5-6 times weekly, and CAPD was increased to six 2-liter exchanges/day. Mean serum urea was 78.6 +/- 27.4 mg/dl (range 45-110); serum creatinine was 6.5 +/- 3.7 mg/dl (3.3-9.8 mg/dl); and hematocrit was 28.9 +/- 3.3 vol% (22-35 vol%). Anemia was partially controlled with rHuEpo in 8 patients. Significant problems were polyhydramnios in 7 cases (5 HD/2 CAPD), oligohydramnios in 1 (HD), gestational diabetes in 2 (CAPD), premature labor with spontaneous abortion at the 19th, 22nd and 28th weeks of gestation (2 HD/1 CAPD), hypertension in 8 (7 HD/1 CAPD), and sterile eosinophilic peritonitis in 1 case (CAPD). Mean gestational age at delivery in 14 successful pregnancies (12 HD/2 CAPD) was 32.3 +/- 2.6 weeks (27-36 weeks) and mean baby weight was 1,400.7 +/- 579.1 g (range 720-2,650 g). No congenital fetal abnormality was observed. Respiratory distress was observed in 6 infants, with 2 deaths (1 HD/1 CAPD) in the first week after delivery. In this study, successful pregnancies were reported in 70.6% of dialyzed women with uremia, with hemodialysis having a rate of fetal survival of 78.6% and CAPD with 33.3%.

Recurrence of focal segmental glomerulosclerosis associated with Kimura's disease after kidney transplantation.

A 13-year-old Brazilian boy with Kimura's disease (eosinophylic lymphoid granuloma) and nephrotic syndrome is reported. Native kidney biopsy showed focal segmental glomerulosclerosis (FSGS). Treatment with prednisolone resulted in partial remission of proteinuria, and he had a progressive loss in renal function, requiring initiation of chronic dialysis, which he underwent for 46 months. After kidney transplantation, the patient developed proteinuria. A renal biopsy showed recurrence of focal segmental glomerulosclerosis, and subsequently he developed renal insufficiency.

Early elevation of lipoprotein(a) levels in chronic renal insufficiency.

Serum lipoprotein(a) [Lp(a)] concentrations in chronic renal failure patients were investigated in relation to the degree of renal insufficiency, treatment by maintenance hemodialysis, and correction of uremia by renal transplantation with or without cyclosporin immunosuppression. Fast serum levels of Lp(a) (mg/100 mL) were determined in 34 chronic renal failure patients not in need of maintenance dialysis (16 with serum creatinine 2.0-4.0 mg/100 mL; 18 with serum creatinine higher than 4.0 mg/100 mL), 40 patients treated by hemodialysis, 55 successful renal transplant recipients (28 under cyclosporin treatment and 27 receiving no cyclosporin), and 34 healthy controls. Age and sex distributions were similar among groups. Pregnant women; non-White individuals; subjects with obesity, diabetes, nephrotic syndrome, and hepatic and thyroid diseases; and those treated with oral contraceptives or lipid-lowering drugs were excluded from the study. Compared to controls, median Lp(a) was increased in nondialyzed renal failure patients (11 vs. 47.5 p < 0.001) and this was the only lipid abnormally observed in the group. There was no significant difference in Lp(a) levels between nondialized renal failure patients with serum creatinine 2.0-4.0 and > 4.0 mg/100 mL (47 vs. 49, NS). Moreover, Pearson correlation coefficient (r = 0.01, NS) showed that Lp(a) values were not related to serum creatinine in nondialyzed patients, In hemodialysis subjects Lp(a) concentrations (median = 29) were intermediate between those observed in nondialyzed patients and controls but the differences were not significant. Lp(a) levels in renal transplant patients treated with cyclosporin (median = 6) and not receiving cyclosporin (median = 13) were similar and did not differ from controls. Serum Lp(a) increases and attains maximum levels with mild/moderate reduction in renal function, and does not seem to change through late renal failure stages or in relation to the introduction of maintenance hemodialysis treatment. Correction of uremia by successful renal transplant caused normalization of Lp(a) levels regardless of the use of cyclosporin. Increased Lp(a) levels may be the earliest and more consistent lipid alteration seen in predialysis renal failure.

Haemodialysis without anticoagulant: haemostasis parameters, fibrinogen kinetic, and dialysis efficiency.

BACKGROUND: Haemodialysis without anticoagulant is an alternative to systemic anticoagulation of patients at high risk of bleeding. However, reports have suggested that heparin-free haemodialysis might results in blood defibrination, and fibrin deposition in dialytic membrane with possible reduction in dialyser efficiency. METHODS: Haemostasis parameters, fibrin-fibrinogen kinetic assessed by 125I-fibrinogen (125I-F) turnover and 125I-fibrinogen deposition within the dialyser membranes, and dialytic efficiency were studied in 10 stable chronic uraemic patients. Each patient was dialysed on two consecutive 4-h dialyses, once with each of two dialysis strategies: haemodialysis without anticoagulant and conventional haemodialysis using heparin as anticoagulant. RESULTS: No significant changes were seen in mean platelet count, plasma fibrinogen, prothrombin time, and antithrombin III during haemodialysis without anticoagulation, and these parameters were not different from those in patients who underwent conventional haemodialysis. Compared with the predialysis values, a shortening of the mean aPTT from an initial mean value was noted (P < 0.05) in haemodialysis without anticoagulation at 60, 120 and 240 min. Fibrin-fibrinogen degradation products remained unchanged during conventional haemodialysis, but were increased after the 30th minute of haemodialysis without anticoagulation (P < 0.05), although all values were in normal range. The biological half-life of 125I-F in uraemic patients before the haemodialysis was 5.02 +/- 0.43 days (control). There was a significant fall in 125I-F half-life during haemodialysis without anticoagulation (2.56 +/- 0.58 days; P < 0.01) but not during conventional haemodialysis (4.77 +/- 0.97, NS). After use each dialyser was dismantled and 125I-F deposition within the membranes (M#5, M#12 and M#19) was measured. During haemodialysis without anticoagulation mean fibrin deposition in M# (28.74 +/- 10.50 x 10(3) counts), M#12 (26.42 +/- 9.06 x 10(3) counts), and M#19 (21.97 +/- 8.33 x 10(3) counts) was greater (P < 0.001) than that during conventional haemodialysis (1.70 +/- 0.92 x 10(3), 1.33 +/- 0.65 x 10(3), and 1.59 +/- 1.03 x 10(3) counts respectively). However, this greater deposition of fibrin on membranes during haemodialysis without anticoagulation did not change dialyser efficiency as assessed (haemodialysis without anticoagulation vs conventional haemodialysis) by change in serum urea (-53.96 +/- 3.38% vs -51.96 +/- 5.20%, NS), serum creatinine (-48.65 +/- 5.99% vs -49.59 +/- 6.65%, NS), serum potassium (-30.06 +/- 4.46% vs -27.64 +/- 2.81%, NS), serum bicarbonate (+25.91 +/- 1.39% vs +24.89 +/- 2.59%, NS) and haematocrit (+3.20 +/- 3.99% vs 2.15 +/- 2.01%, NS). The mean Kt/V was similar for conventional haemodialysis (0.870 +/- 0.074) and haemodialysis without anticoagulation (0.873 +/- 0.107). CONCLUSION: In conclusion, although conventional haemostasis parameters remained unchanged during haemodialysis without anticoagulation, some degree of activation of coagulation system occurs, haemodialysis without anticoagulation was associated with greater decline in 125I-F half-life and greater fibrin deposition on dialyser membranes, but with no change in dialyser efficiency.

Potassium is not a good solute to estimate residual volume in CAPD.

Residual volume is defined as the volume of dialysate remaining in the peritoneal cavity after complete drainage of fluid. In this study the residual volume was estimated in 9 patients, age 42 +/- 9 years, on continuous ambulatory peritoneal dialysis (CAPD) for 14 +/- 12 months, using two different solutes: dextran 70 and potassium. The residual volume was calculated from the change induced in drain dialysate solute concentration by the known volume and solute concentration of the newly infused dialysis solution. The residual volume estimated with dextran 70 was 195 +/- 105 mL (75-375 mL) and with potassium 411 +/- 108 mL (245-596 mL) (K > D, p < 0.001). The correlation between these two measurements was close to significance (r = 0.654; p = 0.056). In conclusion, potassium overestimates the residual volume, probably because of its rapid diffusion during the infusion time.