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Biomedical subjects

S Q Lew

Publications and source records attributed to S Q Lew.

34 records · Page 2Linked to original sources
PubMed1995

Clotting by heparin of hemoaccess for hemodialysis in an end-stage renal disease patient.

Clotting of vascular access in hemodialysis patients remains a significant problem. The routine use of heparin to anticoagulate the blood during hemodialysis has been helpful in increasing the life span of vascular access in these patients. However, the use of heparin is not without complications. Heparin-induced thrombocytopenia is one of the well-recognized drug-induced thrombocytopenic disorders that by itself usually does not cause serious morbidity. A small proportion of these patients concomitantly develop "paradoxic" acute thrombotic complications. Myocardial infarction, ischemic damage to lower extremities leading to amputation, and cerebrovascular accident with permanent neurologic deficits or leading to death are just some of the disastrous complications. We report a case of paradoxic clotting of the hemoaccess in a patient receiving hemodialysis treatment associated with the use of heparin that has not been previously described. The patient had heparin-dependent platelet antibody resulting in a decrease in platelet count and clotting of the hemoaccess.

Adult↗
PubMed1994

Assessment of adequacy in peritoneal dialysis.

Adequacy of peritoneal dialysis has been less well studied than that of hemodialysis. Fractional urea removal, total creatinine removal, and various indices have been proposed to reflect or predict patient morbidity and mortality. No prospective study has been published in this regard. To evaluate this area further, in addition to reviewing selected literature, 45 continuous ambulatory peritoneal dialysis (CAPD) patients were recruited in two dialysis centers for a prospective study on treatment adequacy. Patients were well rehabilitated and had no peritonitis or hospitalization in the 6 months before the study. Urea and creatinine kinetics were analyzed, as were dietary intake and fluid balance. The weekly Kt/V, calculated to include peritoneal and residual renal clearance (KprT/V), averaged 1.77 with a Kt/V hemodialysis equivalent of 0.59. Patients with residual renal function (58% of the studied population) had an average residual renal clearance of 3.42 mL/min, and had lower steady-state concentrations of urea nitrogen and creatinine in the plasma than patients with no residual renal function. As a consequence, a lower percent excretion of urea and creatinine in the peritoneal fluid was observed in the former patients compared with the latter, where the peritoneal route was the only one for solute excretion. The concentration profiles in blood appear to be the critical factor in achieving the final target of the treatment, ie, the excretion of the overall amount of waste products derived from protein and other metabolic pathways. The constant blood levels in CAPD explain why such a low Kt/V can be adequate whereas, in hemodialysis, a higher Kt/V is required.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

How to measure residual renal function in patients on maintenance hemodialysis.

Many patients with end-stage renal disease who are on maintenance hemodialysis still have significant residual renal function. Exogenous markers such as inulin and radionuclides, and endogenous markers such as creatinine and urea are commonly used to quantify this residual function. These various methods are described in detail and compared with one another. Residual renal function needs to be considered when the dialysis prescription is written. This contribution of residual renal function to dialysis adequacy and its importance are discussed.

Biomarkers↗
PubMed1992

Urea and creatinine generation and removal in a pregnant patient receiving peritoneal dialysis.

Peritoneal dialysis is the preferred form of dialysis during pregnancy because it is continuous and lacks the wide variation in chemistries, weight and blood pressure, and avoids the use of anticoagulation necessary during hemodialysis. This is a case report of a successful vaginal delivery of a 35 week healthy baby boy to a patient with end stage renal disease receiving peritoneal dialysis. Approximately one year after starting peritoneal dialysis for end stage renal disease of unknown etiology, this patient was noted to be pregnant during a transplant evaluation. BUN and creatinine generation increased with pregnancy. In order to keep the plasma BUN less than 50 mg/dl and creatinine less than 5 mg/dl, BUN and creatinine removal were increased by increasing the liters of dialysate from 8 liters to 16 liters per day. The peritoneal volume decreased from an initial 2 liters to 0.8 liter per exchange. The frequency of exchange increased. This was accomplished at home with a cycler so the patient was able to continue self care and maintain a quality of life. Peritoneal equilibration test during pregnancy did not change.

Adult↗
PubMed1991

Hypoventilation in a dialysis patient with severe metabolic alkalosis: treatment by hemodialysis.

A patient with end-stage renal disease (ESRD) developed metabolic alkalosis and alkalemia from protracted vomiting. As a result of the absence of the alkali excretory capacity in this patient with ESRD, the alkaline load accumulated rapidly. Once the amount of acid lost from vomiting exceeded the amount of acid gained from metabolism, alkalemia supervened. The initial arterial blood gas on room air revealed hypercarbia, hypoxia and alkalemia. Her serum bicarbonate was greater than 50 mEq/l. Compensatory hypoventilation occurred. In this report, the extent of compensatory hypoventilation in the setting of metabolic alkalosis in patients treated for ESRD and therapeutic approaches to this problem will be discussed. Treatment was aimed at correcting the primary disorder, namely metabolic alkalosis. Conventional bicarbonate dialysis was shown to be effective in improving acid-base homeostasis in this patient.

Alkalosis↗
PubMedDate not supplied

Dialysis access related infections.

Infection is a common cause of morbidity and mortality in end-stage renal disease patients. Unintentional pathogens are introduced into an immunocompromised host during hemodialysis and peritoneal dialysis by means of the access (arteriovenous fistula, arteriovenous graft, central venous catheter, or peritoneal dialysis catheter). Gram positive organisms are most common with Staphylococcus aureus and coagulase negative Staphylococcus predominating. Preventive measures are mandatory and the key to decreasing infection rates.

Arteriovenous Shunt, Surgical↗
PubMedDate not supplied

Pharmacokinetics of zidovudine in HIV-infected patients with end-stage renal disease.

We determined the pharmacokinetics of zidovudine (AZT) and its metabolite (GAZT) in HIV-infected patients with end-stage renal disease (ESRD), between dialysis sessions, and compared these to HIV-infected patients with normal renal function. Clearance of AZT in ESRD patients was not significantly different from controls. The mean serum AZT levels in ESRD patients were six times greater than the levels in normal controls at 4 h. Serum levels of GAZT were higher in ESRD patients at 90 min, and by 4 h were more than an order of magnitude greater than normal controls. If the AZT serum level is a good index of toxicity, we conclude that the currently recommended dose of 200 mg AZT three times a day is probably safe for use in HIV-infected patients with ESRD. The enterohepatic metabolism of AZT, the effect of such a dosing schedule and the effects of circulating levels of GAZT on outcomes in HIV-infected patients with ESRD must be further investigated.

Adult↗
PubMedDate not supplied

The impact of residual renal function and total body water volume on achieving adequate dialysis in CAPD.

AIMS: The objective is to evaluate the impact of residual renal function (RRF) and total body water (TBW) on achieving adequate dialysis. METHODS: Sixty three CAPD patients performing four 2 liter exchanges daily were evaluated for RRF, total weekly Kt/V (TWKt/V), total weekly creatinine clearance (TWCC) and TBW. RESULTS: In patients with residual renal function (N = 41), TWKt/V and TWCC were 2.2 +/- 0.8 and 77.4 +/- 24.5 L, respectively. In patients without RRF (N = 22), TWKt/V was 1.6 +/- 0.4 and TWCC 42.6 +/- 9.2 L. TBW correlated negatively with TWKt/V in the group without RRF (r = -0.75, P<0.001). CONCLUSION: It is not possible for larger patients without RRF treated with CAPD (2L x 4 exchanges) to achieve the acceptable targets for TWKt/V and TWCC due to TBW.

Adult↗