Vanishing RKKY interactions in Ce-based cage compounds.

We report the results of thermodynamic measurements in external magnetic field of the cubic Ce-based cage compounds CeT2Cd20(T= Ni,Pd). Our analysis of the heat-capacity data shows that the Γ7doublet is the ground state multiplet of the Ce3+ions. Consequently, for the Γ7doublet it can be theoretically shown that the Ruderman-Kittel-Kasuya-Yosida interaction between the localized Ce moments mediated by the conduction electrons, must vanish at temperatures much lower than the energy separating the ground state doublet from the first excited Γ8quartet. Our findings provide an insight as to why no long range order has been observed in these compounds down to temperatures in the milliKelvin range.

Scale-invariant magnetoresistance in a cuprate superconductor.

The anomalous metallic state in the high-temperature superconducting cuprates is masked by superconductivity near a quantum critical point. Applying high magnetic fields to suppress superconductivity has enabled detailed studies of the normal state, yet the direct effect of strong magnetic fields on the metallic state is poorly understood. We report the high-field magnetoresistance of thin-film La2-x Sr x CuO4 cuprate in the vicinity of the critical doping, 0.161 ≤ p ≤ 0.190. We find that the metallic state exposed by suppressing superconductivity is characterized by magnetoresistance that is linear in magnetic fields up to 80 tesla. The magnitude of the linear-in-field resistivity mirrors the magnitude and doping evolution of the well-known linear-in-temperature resistivity that has been associated with quantum criticality in high-temperature superconductors.

Unfolding the physics of URu2Si2 through silicon to phosphorus substitution.

The heavy fermion intermetallic compound URu2Si2 exhibits a hidden-order phase below the temperature of 17.5 K, which supports both anomalous metallic behavior and unconventional superconductivity. While these individual phenomena have been investigated in detail, it remains unclear how they are related to each other and to what extent uranium f-electron valence fluctuations influence each one. Here we use ligand site substituted URu2Si(2-x)P(x) to establish their evolution under electronic tuning. We find that while hidden order is monotonically suppressed and destroyed for x≤0.035, the superconducting strength evolves non-monotonically with a maximum near x≈0.01 and that superconductivity is destroyed near x≈0.028. This behavior reveals that hidden order depends strongly on tuning outside of the U f-electron shells. It also suggests that while hidden order provides an environment for superconductivity and anomalous metallic behavior, it's fluctuations may not be solely responsible for their progression.

A single-institution review of portosystemic shunts in children: an ongoing discussion.

PURPOSE: Review the safety and long-term success with portosystemic shunts in children at a single institution. METHODS: An IRB-approved, retrospective chart review of all children ages 19 and undergoing surgical portosystemic shunt from January 1990-September 2008. RESULTS: Ten patients were identified, 8 females and 2 males, with a mean age of 15 years (range 5-19 years). Primary diagnoses were congenital hepatic fibrosis (5), hepatic vein thrombosis (2), portal vein thrombosis (2), and cystic fibrosis (1). Primary indications were repeated variceal bleeding (6), symptomatic hypersplenism (2), and significant liver dysfunction (2). Procedures performed were distal splenorenal bypass (4), side-to-side portocaval shunt (3), proximal splenorenal shunt (2), and an interposition H-graft portocaval shunt (1). There was no perioperative mortality and only minor morbidity. Seventy percent of patients had improvement of their symptoms. Eighty percent of shunts remained patent. Two were occluded at a median follow-up of 50 months (range 0.5-13.16 years). Two patients underwent subsequent liver transplantation. Two patients died at 0.5 and 12.8 years postoperatively, one from multisystem failure with cystic fibrosis and one from post-operative transplant complications. CONCLUSIONS: The need for portosystemic shunts in children is rare. However, in the era of liver transplantation, portosystemic shunts in selected patients with well-preserved liver function remains important. We conclude that portosystemic shunts are safe and efficacious in the control of variceal hemorrhage and symptoms related to hypersplenism.

To circumcise or not to circumcise? Circumcision in patients with bleeding disorders.

SUMMARY: Circumcision is one of the most common procedures performed in male neonates, but few published reports have described circumcision in patients with bleeding disorders. The aim of this study was to analyse outcomes of circumcision among children evaluated at our institution to determine the extent of complications and to provide guidelines for circumcision management. We searched our patient database for records of children who were followed up at the Mayo Clinic Comprehensive Hemophilia Center from 2000 through 2007 and who had been circumcised. We retrospectively reviewed the medical records to document complications and determine management strategies in this patient population. Of 55 children and young adults identified (median [range] age, 15 years [11 months to 21 years]), 48 patients were circumcised. Indications for circumcision were parental request (n = 45) and medical recommendation (n = 3). Twelve of 21 patients with a known bleeding disorder at the time of circumcision received factor replacement before the procedure. Three of these 21 patients had bleeding complications. Of the other 27 patients, who were diagnosed later in life as having a bleeding disorder, 8 had bleeding complications. The overall incidence of bleeding after circumcision was 23% (11/48). The 23% overall incidence of bleeding complications in our patients with bleeding disorders is comparable to that reported for patients without a bleeding disorder (0.1-35%). Some of our patients had significant bleeding despite adequate factor replacement before and after the procedure. Parents and patients must be aware that bleeding risk is a possibility despite adequate factor replacement for hemostasis.

Management of chronic pancreatitis in the pediatric patient: endoscopic retrograde cholangiopancreatography vs operative therapy.

PURPOSE: The management of chronic pancreatitis (CP) in children is challenging. We compare endoscopic retrograde cholangiopancreatography (ERCP) to operative therapy (OR). METHODS: The study involved review of patients younger than 18 years with CP who underwent ERCP or OR from 1973 to 2007. Follow-up was complete in 95% of patients (median, 6 years; range, 1-23 years). RESULTS: We identified 37 children with CP; 25 (68%) were managed by OR with 20 of these previously failing ERCP. Twelve (32%) were managed by ERCP alone. Mean follow-up was longer in the OR group (5.1 vs 2.1 years; P = .02). Patients with idiopathic pancreatitis (58% vs 13%; P = .04) and patients with a later onset of pancreatitis (12.0 vs 7.4 years; P = .002) were more likely to be managed with ERCP alone. The patients who underwent OR had a lower rate of recurrent pancreatitis (39% vs 75%; P < .0001), although this did not correlate to fewer hospitalizations or less narcotic use compared to ERCP alone. When patients who failed ERCP and progressed to OR were included in the ERCP alone group, ERCP was worse in recurrence (90% vs 39%; P < .0001) and rate of hospitalization (55% vs 33%; P = .04) compared to OR. CONCLUSION: Patients with CP managed by OR have a lower rate of recurrent pancreatitis and hospitalization compared to ERCP.

Central venous access devices for paediatric patients with haemophilia: a single-institution experience.

Use of a central venous access device (CVAD) can facilitate early introduction of home-based infusion of factor concentrate for long-term prophylaxis or immune tolerance therapy in children with bleeding disorders. The aim was to review outcomes associated with use of CVAD. Retrospective review of paediatric patients with bleeding disorders was observed at the Mayo Clinic Comprehensive Hemophilia Center. Thirty-seven CVAD were placed in 18 patients (haemophilia A [n = 15], type 3 von Willebrand disease [n = 2] and haemophilia B [n = 1]). Follow-up was for 45 952 CVAD days, and median time that CVAD remained in place was 1361 days per device. Factor VIII (FVIII) inhibitors were present in 4 of the 15 patients. Ten CVAD-related infections occurred (median, 672 days; range, 72-1941 days), of which six were in one patient with FVIII inhibitors. Overall infection rate was 0.22 (95% confidence interval [CI], 0.10-0.40) per 1000 CVAD days, with 0.11 infections in patients without FVIII inhibitors compared with a pooled incidence of 0.66 (95% CI, 0.44-0.97) reported in the literature. Indications for removal of 27 CVAD were blockage, change to peripheral venous access, catheter displacement, infection, leak in the port septum, short catheter and skin erosion. No clinically apparent thrombosis or sequelae of thrombosis were observed. Infection is the most common complication associated with CVAD use and is increased in patients who have inhibitors. The low rate of clinically apparent thrombosis reflects our practice of not screening for thrombosis. The low infection rate reflects our practice of using and reinforcing the aseptic technique.

Surgical management of intestinal malrotation in adults: comparative results for open and laparoscopic Ladd procedures.

BACKGROUND: This study aimed to characterize the clinical features of intestinal malrotation in adults, and to compare the results for the open and laparoscopic Ladd procedures. METHODS: Between 1984 and 2003, 21 adult patients with a mean age of 36 years (range, 14-89 years) were surgically treated for intestinal malrotation. The clinical data collected included age, gender, presenting symptoms, diagnostic tests, type of operation, operative time, narcotic requirement, time to oral intake, length of hospital stay, and outcome. The groups (open vs laparoscopic) were comparatively analyzed using two-sample t-tests and Wilcoxon rank sum tests. RESULTS: The two groups were similar in terms of age, clinical presentation, and diagnostic tests performed. The most common presenting symptoms were chronic abdominal pain, nausea, and repeated vomiting. Upper gastrointestinal barium studies (UGI/SBFT) were diagnostic for all patients with malrotation as compared with computed tomography (CT) scanning, which was falsely negative in 25% of patients. A total of 21 patients underwent the Ladd procedure, either open (n = 10) or laparoscopic (n = 11). Three laparoscopic procedures were converted to open. Overall, the laparoscopic group resumed oral intake earlier than the open group (1.8 vs 2.7 days; p = 0.092), had a shorter hospital stay (4.0 vs. 6.1 days; p = 0.050), and required less intravenous narcotics on postoperative day 1 (4.9 vs 48.5 mg; p = 0.002). The laparoscopic group underwent a longer operation (194 vs 143 min; p = 0.053). Sixteen of eighteen patients available for follow-up reported complete resolution of symptoms, 2 felt greatly improved. No patient required a second operation related to volvulus or recurrent symptoms. CONCLUSIONS: The laparoscopic Ladd procedure is feasible, safe, and as effective as the standard open Ladd procedure for the treatment of adults who have intestinal malrotation without midgut volvulus. Patients also benefit from this minimally invasive approach, as manifested by an earlier oral intake, a decreased need for intravenous narcotics, and an earlier discharge from the hospital.

Cause-specific and total mortality in the Canterbury (New Zealand) insulin-treated Diabetic Registry population: a 15-year follow-up study.

AIMS: To establish all-cause and cause-specific death rates, and risk factors for mortality in insulin-treated diabetic individuals living in the province of Canterbury, New Zealand. METHODS: Insulin-treated diabetic subjects (n = 995) on the Canterbury Diabetes Registry were followed up over 15 years and vital status determined. Death rates were standardized and hazard regression was used to model the effects of demographic covariates on relative survival time. RESULTS: There were 419 deaths in 11 226.3 person-years of follow-up with a standardized mortality ratio (SMR) of 2.0 (95% confidence interval (CI) 1.8-2.2). Relative mortality was greatest for the group aged 0-29 years (SMR 3.0 (95% CI 2.4-3.7)). After controlling for diabetes duration and gender, a 10-year increment in age of onset was associated with a 33% decrease in relative hazard (95% CI 29-36%), indicating that excess mortality due to diabetes declines with rising age of onset. After controlling for age of onset and gender, each 10-year increment in duration of diabetes is associated with a 26% decrease in relative hazard (95% CI 24-29%), indicating that with longer survival the mortality hazard approaches the general population hazard. Relative mortalities were increased for cardiovascular, renal and respiratory disease, but not malignancy. Relative mortality from acute metabolic complications was increased in the subgroup with age of onset of diabetes < 30 years and requiring insulin within 1 year of diagnosis. CONCLUSIONS: Mortality rates are high for insulin-treated diabetic individuals relative to the general population.

Predictors of mortality from type 2 diabetes mellitus in Canterbury, New Zealand; a ten-year cohort study.

The aim was to establish mortality rates in a cohort of subjects with type 2 diabetes mellitus over 10 years in Canterbury, New Zealand (NZ) and to determine baseline prognostic factors. Subjects (447) with type 2 diabetes (208 male, 239 female; age range 30-82 years, median 62 years; of predominantly European origin) were characterised in a clinic survey in 1989. Individual status (dead or alive) at June 1 1999 (10 year follow-up) was ascertained. Mortality rates were compared with the general NZ population and the relative risk (RR) of baseline prognostic factors evaluated with Cox's proportional hazards model. At 10 years, 232 subjects were confirmed as alive and 187 as dead - only 28 were untraceable. Ten year survival was 55% (95% CI: 50-60) for the cohort, compared with 70% (95% CI: 65-75) at 6 years. Factors assessed at baseline (1989), that were independently prognostic of total mortality, included age (RR 2.0, 95% CI: 1.6-2.5), pre-existing coronary artery disease (CAD; RR 1.7, 95% CI: 1.2-2.4) and albuminuria (RR 1.58, 95% CI: 1.1-2.3). Glycated haemoglobin was not a significant predictor of total mortality, although was a predictor of CAD mortality in those subjects free of CAD in 1989 (RR 1.6, 95% CI: 1.1-2.3). In the latter subset, independent prognostic factors for CAD mortality also included age (RR 2.5, 95% CI: 1.7-3.8), hypertension (RR 1.9, 95% CI: 1.0-3.7), peripheral vascular disease (RR 2.4, 95% CI: 1.3-4.5) and smoking (RR 2.6, 95% CI: 1.2-5.8). Increased mortality in type 2 diabetic subjects is therefore attributable to multiple risk factors. Improved outcomes will depend on interventions targeted at glycaemic and all other remediable factors.

Age at diagnosis, glycaemic control and the development of retinopathy in a population-based cohort of Type 1 diabetic subjects in Canterbury, New Zealand.

The aim was to determine the relationship between age at diagnosis, glycaemic control and the development of retinopathy in a population-based cohort of Type 1 diabetic subjects. At 1 January 1984, there were 286 individuals with Type 1 diabetes (and age of onset<20 years) on the Canterbury, New Zealand population register who had at least 2 prospective HbA(1c) readings (from 1 January 1984). Of these, 107 already had retinopathy. Of the 179 subjects without retinopathy at baseline 63 developed retinopathy during follow-up. After controlling for duration of diabetes (in the whole group), age at diagnosis was found to be a significant predictor of HbA(1c) level (P=0.001), with higher (mean+/-SD) baseline HbA(1c) in the 10-14 age group (7.95+/-2.14%), compared with (7.62+/-1.77%) in the <10 year group and (7.39+/-2.57%) in the >14 year group. The major predictors of retinopathy (in those without retinopathy at baseline), however were duration of diabetes (mean time to development of retinopathy decreases by 14% (95% CI 10-17%) for each year), baseline HbA(1c) (for each unit increase, mean time to development of retinopathy decreased by 23% (95%CI 13-32%) and HbA(1c) slope (average annual change). Peri-pubertal age at diagnosis (10-14 years) did not influence the time to onset of retinopathy over and above that attributed to duration of diabetes and glycaemic control.

All-cause mortality in the Canterbury (New Zealand) insulin-treated Diabetic Registry population.

OBJECTIVE: To establish all-cause death rates and life expectancies of and risk factors for mortality in insulin-treated diabetic individuals living in Canterbury, New Zealand. RESEARCH DESIGN AND METHODS: Insulin-treated diabetic subjects (n = 1,008) on the Canterbury Diabetes Registry were tracked over 9 years, and their vital status was determined. Death rates were standardized using direct and indirect methods. Cox proportional hazard regression was used to model the effects of demographic and clinical covariates on survival time. RESULTS: At study entry, age ranged from 2.9 to 92.7 years, with mean 48.7 +/- 20.4 years; age at diagnosis was 0.2-88.9 years, mean 34.5 +/- 20.0 years; and duration of diabetes was 0.1-58.5 years, mean 14.0 +/- 10.6 years. There were 303 deaths in 7,372 person-years of follow-up with a standardized mortality ratio (SMR) of 2.6 (95% CI 2.4-3.0). Relative mortality was greatest for those aged 30-39 years (SMR 9.2 [4.8-16.2]). The death rate for the diabetic cohort standardized against the Segi world standard population was 16.2 per 1,000. Attained age, sex, and clinical subtype were significant predictors of mortality The SMR for subjects with type 1 diabetes and age at onset <30 years was 3.7 (CI 2.7-5.0), 2.2 (1.8-2.6) for those with onset > or =30 years, and 3.1 (2.5-3.7) for subjects suspected of having latent autoimmune diabetes in adulthood or insulin-treated type 2 diabetes. Life expectancy was reduced for both sexes at all ages. CONCLUSIONS: Mortality rates for insulin-treated diabetic individuals remain high, resulting in shortened life spans relative to the general population. Marked differences in mortality exist between clinical groups of subjects. Further research is needed to improve diabetes classification and to clarify differences in health outcomes.

Videoendoscopic thoracic aorta-to-femoral artery bypass in the pig.

BACKGROUND: The thoracoscopic approach to the aorta has the advantages of easy aortic dissection, excellent inflow, improved exposure in the thorax without insufflation, and ability to employ both laparoscopic and traditional instruments. Our aim was to develop a thoracoscopic technique for descending thoracic aorta-to-femoral artery bypass (TAFB) in the pig that results in acceptable short-term survival and graft patency. MATERIALS AND METHODS: Thoracoscopic TAFB was performed in 11 pigs. Using two-lung ventilation, the animals were placed in a 45 degrees left lateral semidecubitus position. A fan lung retractor, two dissecting ports, intercostal artery loops, and camera were placed through five 10- to 20-mm thoracoscopic incisions. After aortic dissection, an 8-mm graft was passed through a retroperitoneal tunnel. Rumel tourniquets were used for aortic occlusion after placement of a shunt. End-to-side endoscopic anastomosis was completed with knots tied extracorporeally. The left femoral anastomosis was completed under direct vision. Duplex ultrasound of the graft was done on postoperative days 1, 3, and 7. RESULTS: Thoracoscopic TAFB was completed in all animals. Mean aortic anastomosis time was 57 min (range, 34-145); and mean cross-clamp time, 74 min (range, 53-155). Mean operative time was 310 min; the first six operations lasted longer than the last five (338 min vs 276 min, P < 0.04). Average blood loss was 611 ml (range, 250-1300). Two animals died due to anesthetic complications. One (11%) of the nine surviving pigs died on day 2 due to bleeding. Complications were paraplegia in one (11%) and graft thrombosis in another (11%). CONCLUSIONS: Videoendoscopic TAFB can be completed in pigs with acceptable short-term patency and survival. Further experience in thoracoscopic techniques can make TAFB a feasible and low-risk option for selected patients with aortoiliac occlusive disease.

Clinical and biochemical outcomes of type 2 diabetes mellitus in Canterbury, New Zealand: a 6-year cohort study.

There is a paucity of data regarding outcomes of Type 2 diabetes mellitus. A cohort of 447 Type 2 diabetic subjects (208 male, 239 female; age range 30-82 years, median 62 years; and of predominantly European origin) was characterised in a clinic survey in 1989. Individual status (dead or alive) at 1 June 1995 was ascertained. At 6 years, 289 subjects were confirmed as alive and 133 as dead--only 25 were untraceable. Of those subjects identified as alive, follow-up clinical and biochemical data were obtained for 253 (87.5%) individuals. In those subjects, glycated haemoglobin deteriorated from 63.1 +/- 18.7 mmol/mol haem in 1989 to 71.7 +/- 24.4 in 1995, P < 0.0001. An increased prevalence of retinopathy was evident at 6-year follow-up, 59.7% cases in 1995 compared with 39.5% in 1989, P < 0.001. Similarly there was an increased prevalence of coronary artery disease (CAD) (33.6 vs 18.2% of cases), albuminuria (26.5 vs 19% of cases; P < 0.001), and hypertension (71.5 vs 54.9% of cases; P < 0.001) in 1995 vs 1989, respectively. Multiple logistic regression analysis showed that glycated haemoglobin (odds ratio (OR) for 18 mmol/mol haem change, 1.78; 95% CI, 1.15-2.85), hypertension (OR, 3.33; 95% CI, 1.40-8.41) and known duration of diabetes (OR for 7 year change, 2.12; 95% CI, 1.24-3.80) were predictors for development of retinopathy. There is therefore a deterioration in glycaemic control in Type 2 diabetes over 6 years and an increased prevalence of complications that present strategies in a multidisciplinary specialist diabetes clinic are unable to prevent on a sustainable basis.

Lipid but not glycaemic parameters predict total mortality from type 2 diabetes mellitus in Canterbury, New Zealand.

A cohort of 447 subjects with Type 2 diabetes mellitus (208 male, 239 female; age range 30-82, median 62 years; and of predominantly European origin) was characterized in a clinic survey in 1989. Individual status (dead or alive) at 1 June 1995 was ascertained. Mortality rates were compared with the general New Zealand population by calculating standardized mortality ratios (SMR) and the hazard ratio (HR) of prognostic factors evaluated with Cox's proportional hazards model. At 6 years, 289 subjects were confirmed as alive and 133 as dead; only 25 were untraceable. Six-year survival for the cohort was 70% (95% CI 66-74). SMR was 2.53 (95% CI 1.99-2.68) for the female cohort and 2.03 (95% CI 1.60-2.59) for the male cohort. Factors assessed at baseline (1989) that were independently prognostic of total mortality included age, male sex, pre-existing coronary artery disease (CAD) (HR 2.2, 95% CI 1.5-3.3) and plasma cholesterol (HR for 1.4 mmol l(-1) change: 1.49, 95% CI 1.2-1.9). HDL-cholesterol was protective in women (HR for 0.4 mmol l(-1) change: 0.72, 95% CI 0.51-1.00) but not men. Glycated haemoglobin was not a significant predictor of total mortality. Predictors of CAD mortality (in those subjects free of CAD in 1989) included plasma cholesterol (HR for 1.4 mmol l(-1) change: 1.86 95% CI 1.20-2.89), glycated haemoglobin (HR for 1.8% change: 1.9 95% CI 1.04-3.47), male sex, peripheral vascular disease, and smoking. There is therefore increased mortality in Type 2 diabetic subjects in Canterbury, New Zealand. HDL-cholesterol is protective against total mortality in females.

Intraoperative electron irradiation in the management of pediatric malignancies.

BACKGROUND: External beam irradiation (PBRT), especially in children, is limited by the radiosensitivity of normal tissues. Local control remains a problem in abdominopelvic childhood malignancies. Intraoperative electron irradiation (IOERT) has the potential to increase the dose to the tumor, thereby improving local control, without increasing treatment morbidity. METHODS: Between February 1983 and October 1990, 11 children received IOERT as part of a multidisciplinary treatment program for locally advanced primary or recurrent abdominopelvic malignancies. The 7 boys and 4 girls ranged in age from 2-18 years. Tumor histologies included four neuroblastomas, two desmoid tumors, and one each of the following: embryonal rhabdomyosarcoma, synovial cell sarcoma, neurofibrosarcoma, malignant fibrous histiocytoma, and paraganglioma. Single radiation doses of 10-25 grays were delivered using 6-15-megaelectron volt electron beams to 1-5 IOERT fields. All patients also underwent EBRT and six received chemotherapy. RESULTS: Eight patients (73%) were alive and disease free at a median follow-up of 99 months (range, 37-126 months). All eight patients who underwent gross total resection were locally controlled. Three patients required surgical intervention for IOERT-related complications and two patients developed neuropathies. CONCLUSIONS: IOERT as part of a multidisciplinary treatment approach in patients with locally advanced pediatric malignancies appears to enhance local control in those patients in whom a gross total resection is possible. The long term survival rate was encouraging. Further study, with a larger number of patients, appears warranted to more carefully delineate the efficacy and tolerance of IOERT in the pediatric population.

Pediatric sacrococcygeal chordomas: a rare tumor to be differentiated from sacrococcygeal teratoma.

Sacrococcygeal chordoma is a rare pediatric neoplasm that may be confused with the more common, and indolent, teratoma. The present report describes the diagnosis, treatment and early postoperative convalescence of a case of chordoma in an adolescent child. This case is contrasted to the sacrococcygeal teratoma, a familial pediatric neoplasm, and the literature is reviewed with respect to presentation and treatment.

Sorbitol 2.5% mannitol 0.54% irrigation solution for hysteroscopic endometrial ablation surgery.

PURPOSE: To determine if systemic absorption of sorbitol 2.5%/mannitol 0.54% irrigation solution (165 mosm.L-1) during hysteroscopic endometrial ablation with diathermy is associated with hyponatraemia and hypoosmolality. METHODS: In 35 day surgery patients in a university hospital we measured baseline preoperative variables: serum sodium and creatinine concentrations and osmolality, haematocrit, haemoglobin, urine osmolality and sodium concentration, and weight. Fractional excretion of sodium (FENa) was calculated. The same observations were obtained postoperatively before discharge (one hour post resection). Volumes of intraoperative fluid irrigation intravasation and perioperative intravenous fluid absorption (lactated Ringer's solution) were estimated clinically (volumetric). RESULTS: The mean (+/-SD) serum sodium concentration preoperatively was 140.3 +/- 2.4 mmol.L-1; and postoperatively, 139.7 +/- 2.2 mmol.L-1 (P = NS). The serum osmolality decreased from 285.4 +/- 4.5 to 282.6 +/- 4.1 mmol.kg-1 (P < 0.001). The mean volume of intravasated irrigation fluid was 26.4 ml (range 0-300). During the same time, the FENa increased from 0.57% to 0.79% (P < 0.001). CONCLUSION: In these patients, closely and continuously observed for imbalance between infused and collected irrigation fluid, these was no clinical evidence for hyponatraemic hypoosmolality. However, there was a small 1% +/- 1.5% (mean +/- SD; range -3.4 to 3.6%) decrease in plasma osmolality despite adequate blood volumes as shown by urinary sodium indices.