Exchangeable Potassium Study in Patients Undergoing Chronic Haemodialysis

Seven patients with chronic renal failure treated with haemodialysis for 4 to 24 months were found to have low exchangeable potassium levels. Before dialysis the plasma potassium was normal or somewhat raised (possibly owing to acidosis), though the exchangeable potassium was low. Acidosis was corrected during dialysis; plasma potassium levels fell, but clinical and electrocardiographic changes of hypokalaemia were absent. The level of 1 mEq/litre in the dialysate fluid may be too low for use in prolonged haemodialysis.     

Iron Metabolism in Patients Undergoing Regular Dialysis Therapy

Thirteen patients with chronic renal failure maintained on regular renal dialysis were studied. Seven proved to have iron deficiency on the basis of marrow iron studies, reticulocyte iron uptake, and saturation of the serum iron-binding capacity. They absorbed iron when given it by mouth and were able to utilize it for haemoglobin formation. Iron-deficient patients given 600 mg of ferrous sulphate daily for three months showed an increase in haemoglobin, but the failure to replace stores of iron is probably related to their relatively limited ability to absorb iron and the variable but sometimes considerable blood loss occurring with each dialysis.The loss may be occult, and prolonged iron therapy may be required. This is most safely achieved by giving iron by mouth.     

Clotting Problems with the Teflon-Silastic Arteriovenous Shunt in Patients on Regular Haemodialysis

Episodes of clotting that occurred in 22 patients on regular haemodialysis were studied over a six-month period. The venous pressure during dialysis and the radiology of the Teflon-Silastic arteriovenous shunt were found to be satisfactory guides for the management of the shunt. The failure of the shunt during the early stage was mainly due to technical reasons. Histological study of the excised vessels in removed long-term shunts showed that these had failed because of rigidity and thickening of the vessel wall due to calcium and iron deposits or chronic inflammation, or both.     

Plasma Renin Activity and Blood Pressure in 89 Patients Receiving Maintenance Haemodialysis Therapy

Blood pressure, plasma renin activity, plasma sodium concentration, plasma potassium concentration, dietary sodium intake, and duration of dialysis have been measured under standard conditions in 89 patients on maintenance haemodialysis. No significant relation was found between plasma renin activity and blood pressure. Statistically significant correlations were found between plasma renin activity and plasma sodium concentration and between plasma renin activity and dietary sodium intake.Only one patient was found to have uncontrollable hypertension associated with a markedly raised plasma renin activity. Reasons are given for not performing bilateral nephrectomy in this patient. We believe the low incidence of uncontrollable hypertension and hyperreninaemia in our patients to be due to their slow introduction to haemodialysis, thus preventing violent swings in body weight, blood pressure, and renin secretion.Although plasma renin activity did fall with duration of dialysis, all 15 patients who have been on maintenance dialysis for longer than five years have normal levels.     

Antifungal Dosing Considerations in Patients Undergoing Continuous Renal Replacement Therapy

Purpose of Review

The incidence of systemic fungal infections is increasing among patients admitted to the intensive care unit (ICU). Acute kidney injury (AKI) occurs in one third of ICU patients and approximately 5% require renal replacement therapy (RRT). Among those requiring RRT, continuous RRT (CRRT) is used in more than 70% of cases. This review aims to summarize antifungal dosing management in ICU patients receiving CRRT.

Recent Findings

For most antifungal agents, including new azoles such as posaconazole and isavuconazole, CRRT does not significantly affect antifungal pharmacokinetics (PK) mainly due to drug liver elimination and high protein binding. For fluconazole, increased dose is recommended during CRRT taking into account the type of CRRT mode (CVVHF or CVVHDF), membrane surface, and effluent and dialysis flow rates. A dose increase for itraconazole seems also necessary during CRRT; a dose decrease for flucytosine is probably necessary but data are too scarce to give a strong recommendation.

Summary

In ICU patients receiving CRRT, no dosing adjustment is required for the majority of antifungal agents commonly used to treat invasive fungal infections (IFIs) excepted for fluconazole, itraconazole, and flucytosine. Due to high PK variability, therapeutic drug monitoring should be considered in ICU patients receiving CRRT.

     

Problems of Acid-Base Balance in Rapidly Changing Intertidal Environments

SYNOPSIS. Many physical factors vary widely and rapidly in residualwater bodies left on the shore by the receding tide. Whereasvariations of temperature and salinity depend on climatic conditions,the changes of oxygen and carbon dioxide are mainly governedby biological activities. Typically, such waters become hypoxic-hypercapnicat night and hyperoxic-hypocapnic during the day at low tide.According to findings in single-factor laboratory experiments,all these variables can potentially disturb acid-base balancein tidepool animals. However, the whole response of the organismto the complex natural situation can hardly be predicted andmust be approached in the field or in simulated environments.Measurements on crabs Carcinus maenas acclimated to an artificialtidepool show only moderate hemolymph acid-base changes, duemainly to counteracting influences of the concerted variationsof water oxygen and carbon dioxide. The pH-temperature slopefor these crabs was —0.016 pH unit°C^–1 in agreementwith an imidazole alphastat pattern of acid-base regulation.     

Thrombin-Anti-Thrombin Levels and Patency of Arterio-Venous Fistula in Patients Undergoing Haemodialysis Compared to Healthy Volunteers: A Prospective Analysis

Background

Patients on haemodialysis (HD) are at an increased risk of sustaining thrombotic events especially to their vascular access which is essential for maintenance of HD.

Objectives

To assess whether 1) markers of coagulation, fibrinolysis or endothelial activation are increased in patients on HD compared to controls and 2) if measurement of any of these factors could help to identify patients at increased risk of arteriovenous (AVF) access occlusion.

Patients/Methods

Venous blood samples were taken from 70 patients immediately before a session of HD and from 78 resting healthy volunteers. Thrombin-antithrombin (TAT), D-dimer, von Willebrand factor (vWF), plasminogen activator inhibitor-1 antigen (PAI-1) and soluble p-selectin were measured by ELISA. C-reactive protein (hsCRP) was measured by an immunonephelometric kinetic assay. Determination of the patency of the AVF was based upon international standards and was prospectively followed up for a minimum of four years or until the AVF was non-functioning.

Results

A total of 70 patients were studied with a median follow-up of 740 days (range 72-1788 days). TAT, D-dimer, vWF, p-selectin and hsCRP were elevated in patients on HD compared with controls. At one year follow-up, primary patency was 66% (46 patients). In multivariate analysis TAT was inversely associated with primary assisted patency (r= -0.250, p= 0.044) and secondary patency (r = -0.267, p= 0.031).

Conclusions

The novel finding of this study is that in patients on haemodialysis, TAT levels were increased and inversely correlated with primary assisted patency and secondary patency. Further evaluation is required into the possible role of TAT as a biomarker of AVF occlusion.     

Hepatitis-associated Antigen and Antibody in Haemodialysis Patients and Staff

The screening of a dialysis population for the presence of hepatitis-associated antigen (H.A. antigen) has proved to be of value in locating a probable source of infection and in terminating an outbreak of hepatitis by early detection of H.A. antigen positive patients and staff.     

Longitudinal Liver Stiffness Assessment in Patients with Chronic Hepatitis C Undergoing Antiviral Therapy

Background/Aims

Liver stiffness (LS) measurement by means of transient elastography (TE) is accurate to predict fibrosis stage. The effect of antiviral treatment and virologic response on LS was assessed and compared with untreated patients with chronic hepatitis C (CHC).

Methods

TE was performed at baseline, and at weeks 24, 48, and 72 in 515 patients with CHC.

Results

323 treated (62.7%) and 192 untreated patients (37.3%) were assessed. LS experienced a significant decline in treated patients and remained stable in untreated patients at the end of study (P<0.0001). The decline was significant for patients with baseline LS ≥ 7.1 kPa (P<0.0001 and P 0.03, for LS ≥9.5 and ≥7.1 kPa vs lower values, respectively). Sustained virological responders and relapsers had a significant LS improvement whereas a trend was observed in nonresponders (mean percent change −16%, −10% and −2%, for SVR, RR and NR, respectively, P 0.03 for SVR vs NR). In multivariate analysis, high baseline LS (P<0.0001) and ALT levels, antiviral therapy and non-1 genotype were independent predictors of LS improvement.

Conclusions

LS decreases during and after antiviral treatment in patients with CHC. The decrease is significant in sustained responders and relapsers (particularly in those with high baseline LS) and suggests an improvement in liver damage.     

Cephaloridine Serum Levels in Patients on Maintenance Haemodialysis

Cephaloridine serum half-life was determined in 11 patients undergoing maintenance haemodialysis. Three of them were anephric. The mean cephaloridine half-life was 10·4 hours. There was an inverse correlation between cephaloridine half-life and the duration of maintenance haemodialysis treatment. Reasons for this are discussed.The effect of haemodialysis with the Kiil dialyser on cephaloridine half-life was studied in three patients.Dosage recommendations for patients on maintenance haemodialysis are suggested.     

Transient and Persistent Hypercalcaemia in Patients Treated by Maintenance Haemodialysis

In a group of 32 patients with terminal renal failure the initial hypocalcaemia was corrected after two months'' adequate maintenance haemodialysis. In seven patients hypercalcaemia occurred with a peak incidence after about six months'' treatment. In six of these patients hypercalcaemia was transient and the plasma calcium became normal with haemodialysis alone. In one patient the hypercalcaemia was persistent and the plasma calcium reverted to normal only after subtotal parathyroidectomy. This patient had no radiological bone disease, a normal alkaline phosphatase, and no metastatic calcification of the soft tissues.It is concluded that in some patients with terminal renal failure treated with maintenance haemodialysis autonomy of the parathyroids becomes evident in the absence of bone disease or a raised plasma alkaline phosphatase, and that subsequently with continued dialysis there is a spontaneous involution towards normal parathyroid function.     

Acid-Base Balance Modulates Respiratory and Alimentary Behavior of the Mollusc Lymnaea stagnalis

An active reaction (change of pH) in hemolymph of the freshwater pulmonate mollusc Lymnaea stagnalis is studied in various physiological states: hunger, satiety, and alimentary excitation. In satiated animals the hemolymph pH is shifted to the acid area (7.6 ± 0.003) as compared with hungry animals (7.9 ± 0.05). The satiated individuals are characterized by an increased respiratory activity and decreased food consumption as compared with hungry animals. Acidification of the medium leads to an increase of excitability of the respiratory network interneurons (RPeD1, VD4, VD1/RPD2) and to inhibition of activity of the alimentary network interneurons (R/L CGC), whereas alkalization, to opposite effects. It is suggested that pH is one of factors coordinating activity of functional systems of Lymnaea stagnalis due to effect on neuronal correlates of the respiratory and alimentary behavior.     

Neuropathy Associated with Hepatitis in Patients Maintained on Haemodialysis

During a study of peripheral nerve function in chronic renal failure, 11 patients who were being treated by chronic intermittent haemodialysis developed serum hepatitis. Before the infection there was a trend towards improvement in nerve conduction velocities. A pronounced deterioration in the conduction velocities in motor fibres of peripheral nerves occurred in association with hepatitis. In the months after recovery from the infection there was again a trend towards improvement in conduction velocities. We suggest that this reflects the occurrence of a peripheral neuropathy which is at least in part demyelinating. The neuropathy is related to the serum hepatitis, but its pathogenesis is indeterminate.     

Impact of Triple Therapy in Elderly Patients with Atrial Fibrillation Undergoing Percutaneous Coronary Intervention

Background and Purpose

Selecting an ideal antithrombotic therapy for elderly patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) can be challenging since they have a higher thromboembolic and bleeding risk than younger patients. The current study aimed to assess the efficacy and safety of triple therapy (TT: oral anticoagulation plus dual antiplatelet therapy: aspirin plus clopidogrel) in patients ≥75 years of age with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI).

Methods

A prospective multicenter study was conducted from 2003 to 2012 at 6 Spanish teaching hospitals. A cohort study of consecutive patients with AF undergoing PCI and treated with TT or dual antiplatelet therapy (DAPT) was analyzed. All outcomes were evaluated at 1-year of follow-up.

Results

Five hundred and eighty-five patients, 289 (49%) of whom were ≥75 years of age (79.6±3.4 years; 33% women) were identified. TT was prescribed in 55.9% of patients at discharge who had a higher thromboembolic risk (CHA₂DS₂VASc score: 4.23±1.51 vs 3.76±1.40, p = 0.007 and a higher bleeding risk (HAS-BLED ≥3: 88.6% vs 79.2%, p = 0.02) than those on DAPT. Therefore, patients on TT had a lower rate of thromboembolism than those on DAPT (0.6% vs 6.9%, p = 0.004; HR 0.08, 95% CI: 0.01–0.70, p = 0.004). Major bleeding events occurred more frequently in patients on TT than in those on DAPT (11.7% vs 2.4%, p = 0.002; HR 5.2, 95% CI: 1.53–17.57, p = 0.008). The overall mortality rate was similar in both treatment groups (11.9% vs 13.9%, p = 0.38); however, after adjustment for confounding variables, TT was associated with a reduced mortality rate (HR 0.33, 95% CI: 0.12–0.86, p = 0.02).

Conclusions

In elderly patients with AF undergoing PCI, the use of TT compared to DAPT was associated with reduced thromboembolism and mortality rates, although a higher rate of major bleeding.     

Evaluation of ADA Gene Expression and Transduction Efficiency in ADA/SCID Patients Undergoing Gene Therapy

A capillary electrophoresis (CE) method was developed for ADA/SCID diagnosis and monitoring of enzyme replacement therapy, as well as for exploring the transfection efficiency for different retroviral vectors in gene therapy.     

Predictors of Outcome and Hemorrhage in Patients Undergoing Endovascular Therapy with Solitaire Stent for Acute Ischemic Stroke

Background

Endovascular mechanical thrombectomy is emerging as a promising therapeutic approach for acute ischemic stroke and show some advantages. However, the data of predicting clinical outcome after thrombectomy with Solitaire retriever were limited. We attempt to identify prognostic factors of clinical outcome in patients with acute ischemic stroke undergoing thrombectomy with Solitaire retriever.

Methods

We conducted a retrospective analysis of consecutive acute ischemic strokes cases treated between December 2010 and December2013 where the Solitaire stent retriever was used for acute ischemic stroke. We assessed the effect of selected demographic characteristics, clinical factors on poor outcome at 3 months (modified Rankin score 3–6), mortality at 3 months, and hemorrhage within 24 h (symptomatic and asymptomatic). Clinical, imaging and logistic variables were analyzed. A multivariate logistic regression analysis was used to identify variables influencing clinical outcome, based on discharge NIHSS score change and mRS at 3 months.

Results

Eighty nine consecutive patients with acute ischemic stroke underwent mechanical thrombectomy. Multivariate analysis revealed that admission NIHSS score, Serum glucose and endovascular procedure duration were independently associated with clinical outcome. Sex, NIHSS score at admission, diabetes and time of operation were associated with sICH in 1 day. NIHSS score ≥20 (OR 9.38; 95% CI 2.41–36.50), onset to reperfusion >5 hours (OR 5.23; 95% CI1.34,20.41) and symptomatic intracranial hemorrhage (OR 10.19; 95% CI1.80,57.83) were potential predictive factors of mortality at 3 months.

Conclusion

Multiple pre- and intra-procedural factors can be used to predict clinical outcome, symptomatic intracranial hemorrhage and mortality in acute ischemic stroke patients undergoing endovascular therapy. This knowledge is helpful for patients selection for endovascular mechanical thrombectomy.     

Role of Venous Needle Hub in Extracorporeal Pressure Changes during Haemodialysis

Certain types of stainless steel needles with metal hubs, and also a fistula set with projecting internal edges, were used at the venous end of the haemodialysis circuit and found to be associated with undesirable rises in extracorporeal pressure in 56 to 64% of dialyses. These increases in pressure are likely to be the result of platelet thrombus formation at the hub of the needle brought about by turbulent flow. The use of a plastic cannula and a stainless steel needle with a plastic hub, both of which have smooth internal surfaces, resulted in increases in pressure in only 4 to 12% of dialyses.     

花色豚鼠与白化豚鼠静脉血电解质、酸碱平衡及血气的比较学研究

目的比较研究花色豚鼠与白化豚鼠静脉血电解质、酸碱平衡及血气情况。方法分别取健康成年花色豚鼠和白化豚鼠,利用便携式多功能麻醉机经异氟烷吸入麻醉后,腹主静脉取血,经NOVA血气．电解质分析仪全自动分析测定电解质、酸碱平衡及血气等指标。结果花色豚鼠的Cl-、pH、SBC、PO2、SV O2、O2ct均显著低于白化豚鼠（P〈0．05,P〈0．01）,而PCO2显著高于白化豚鼠（P〈O．05）。结论花色豚鼠的携氧能力明显低于白化豚鼠,可以作为血瘀证和亚健康模型研究较好的实验动物。