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Biomedical subjects

R D Swartz

Publications and source records attributed to R D Swartz.

At least 55 records · Page 3Linked to original sources
PubMed1987

Continuous arteriovenous filtration: an effective treatment for surgical acute renal failure.

Continuous arteriovenous hemofiltration (CAVH) is a new method of renal replacement therapy that has several advantages in the surgical treatment of acute renal failure. We initially learned the technique in laboratory testing and then developed a management protocol. Since 1983 we have used CAVH to treat 61 patients with acute renal failure. This extracorporeal technique consists of arteriovenous cannulation of the femoral vessels, which provides continuous blood flow through a hollow-fiber membrane. Hydrostatic pressure (systole greater than 80 mm Hg) creates an ultrafiltrate at a typical rate of 12 L/day. Volume is replaced with an intravenous solution at a rate to achieve the desired fluid balance, usually a net loss of 1 to 2 L/day. This extracellular fluid exchange typically results in removal of 15 gm of urea nitrogen and 50 mEq of potassium per day. The technique can be used in most intensive care units and has relatively few complications. In addition to being a safe and effective means of renal replacement therapy for acute renal failure, CAVH is particularly advantageous for managing conditions of fluid overload in hemodynamically unstable patients.

Acute Kidney Injury↗
PubMed1986

Kinetics, dynamics, and bioavailability of bumetanide in healthy subjects and patients with chronic renal failure.

Six patients with chronic renal failure (CRF group) and four healthy subjects (HS group) were given 5 mg oral and intravenous doses of bumetanide in a random, crossover design. The CRF group had significantly lower plasma and renal clearances, resulting in a five-to sixfold reduction in the fractional urinary excretion of the drug. The percent free drug in plasma for the CRF group was more than double that for the HS group, and significant correlations were observed for volume of distribution at steady state vs. percent free (r = 0.661; P less than 0.05), nonrenal clearance vs. percent free (r = 0.796; P less than 0.01), and renal clearance vs. creatinine clearance (r = 0.995; P less than 0.001). Although bioavailability was relatively consistent among the HS (0.664 +/- 0.112) and CRF (0.689 +/- 0.149) groups, the absorption-time profiles were more irregular for both groups. Cumulative sodium excretion and overall efficiency of response to bumetanide did not differ significantly between the two routes of administration in either group.

Absorption↗
PubMed1986

Continuous arteriovenous hemofiltration: improved survival in surgical acute renal failure?

Continuous arteriovenous hemofiltration (CAVH) is an effective method for renal failure management that has the potential to decrease mortality rates. This hypothesis has not been comparatively studied. Fifty six patients with acute oliguric renal failure complicating multiple organ failure had measurements of resting energy expenditure by indirect calorimetry, caloric and protein intake, energy balance, and outcome. Two management protocols included hemodialysis, full calories, and low protein (phase I) or CAVH, full calories, and high protein (phase II). The survival rate in phase I was 12% and 28% in phase II (not a statistically significant difference); CAVH did facilitate parenteral feeding. Patients with positive energy balance had improved survival compared with those with significant energy deficit (37.5% versus 9.4%, p less than 0.025). We conclude that full nutritional support improves survival in acute renal failure. The method of renal replacement therapy is of secondary importance, but CAVH has distinct advantages in the nutritional management of surgical patients.

Acute Kidney Injury↗
PubMed1985

Peritoneoscopy in the management of catheter malfunction during continuous ambulatory peritoneal dialysis.

Continuous ambulatory peritoneal dialysis is widely used in the maintenance of patients with chronic renal failure. Obstruction or displacement of the chronic dialysis catheter, which prevents dialysate drainage, can compromise ongoing dialysis. Conservative approaches (body position change, saline infusion, and enema) are often unsuccessful and more aggressive therapy may be required. We report the use of peritoneoscopy to reposition malfunctioning peritoneal dialysis catheters. The procedure proved to be safe and gave excellent long-term results.

Adult↗
PubMed1985

Chronic peritoneal dialysis: mechanical and infectious complications.

The present report summarizes the mechanical and infectious complications attributable to the devices and procedures used for chronic peritoneal dialysis (PD), comparing the type and frequency of such complications in contemporaneous groups of patients undergoing continuous ambulatory PD (CAPD) or intermittent PD (IPD). Mechanical complications related directly to the catheter and its placement proved to be equally frequent during CAPD and IPD. On the other hand, mechanical complications related to increased intraperitoneal pressure were more frequent during CAPD. In most instances mechanical complication can be managed without permanent interruption of chronic PD. Peritonitis occurs more frequently during CAPD (1.6 episodes per patient-year) than during IPD (0.4 episodes per patient-year), with a tendency to more frequent peritonitis among diabetics, children, patients with white blood cell abnormalities, patients with catheter cuff or tunnel inflammation, and during the 1st month of treatment. Medical therapy eradicates peritonitis and allows continuation of chronic PD with retention of the catheter in more than 90% of episodes, although special problems may be encountered with fungal, pseudomonal, and some coagulase-positive staphylococcal infections.

Adolescent↗
PubMed1984

Intraleukocytic sequestration as a cause of persistent Staphylococcus aureus peritonitis in continuous ambulatory peritoneal dialysis.

Peritonitis caused by Staphylococcus aureus in four patients undergoing continuous ambulatory peritoneal dialysis failed to respond to, or relapsed immediately after cessation of, intraperitoneal antibiotic therapy with vancomycin or cephalothin and tobramycin. Sequestration of viable staphylococci within polymorphonuclear leukocytes in the peritoneal fluid was suspected for two reasons: (1) staphylococci could still be grown after treatment of the dialysate cell fraction with lysostaphin, a procedure that kills only extracellular staphylococci, and (2) diminished polymorphonuclear leukocyte bactericidal activity was demonstrated in peritoneal dialysis effluent. Addition of rifampin, which readily penetrates polymorphonuclear leukocytes, to the treatment regimen of all patients led to prompt resolution of peritonitis without relapse.

Adult↗
PubMed1984

Bicarbonate hemodialysis: influence on plasma refilling and hemodynamic stability.

The present study compares the effect of sodium bicarbonate (LoNaHCO3, Na = 134, HCO3 = 33 mEq/l) and sodium acetate (LoNaAc, Na = 134, acetate 33 mEq/1)dialysate on the extravascular fluid mobilization (VFM) and hemodynamic changes in 6 patients during 3 h of hemodialysis with equivalent fluid ultrafiltration of about 600 ml/h. The cumulative decrease in plasma volume after 1, 2 and 3 h of dialysis was significantly less during LoNaHCO3 dialysis than during LoNaAc dialysis, with plasma volume almost completely refilled by VFM during the first 2 h of LoNaHCO3 dialysis. High sodium acetate dialysate (HiNaAc, Na = 144, acetate = 33 mEq/1) with equivalent fluid ultrafiltration also resulted in less net decrease in plasma volume and greater VFM than LoNaAc, although the temporal pattern of refilling was somewhat different from that during LoNaHCO3: rapid and complete refilling during the early portion of LoNaHCO3, slower and more progressive refilling during HiNaAc, with similar cumulative refilling for LoNaHCO3 and HiNaAc by 3 h. Mean arterial pressure (MAP) tended to decrease during LoNaAc dialysis, whereas MAP remained stable during LoNaHCO3 and increased slightly during HiNaAc. This study, therefore, suggests that improved hemodynamic stability utilizing bicarbonate dialysate may be due, in part, to greater plasma refilling and better preservation of plasma volume.

Acetates↗
PubMed1982

Analysis of survival of end-stage renal disease patients.

Traditional life-table analysis of differences in patient survival for various end-stage renal disease (ESRD) treatment modalities ignore the fact the ESRD patients face sequential risks because they frequently experience more than one mode of therapy. A modification of the usual life-table analysis is suggested as being more appropriate. This modified method takes into account the "time-to-treatment" bias, which, in this instance, is the time spent on the first modality of treatment (that is, center dialysis). The survival data of more than 2,000 ESRD patients in the State of Michigan during the 5-year period, 1974 to 1978, are used to illustrate this method.

Adolescent↗
PubMed1982

Preservation of plasma volume during hemodialysis depends on dialysate osmolality.

Hypotension is a major complication of hemodialysis and has been variously attributed not only to plasma volume loss which results from ultrafiltrative fluid removal, but also to extracorporeal blood circulation, osmolar changes or hemodynamic abnormalities which complicate the procedure. The present investigation demonstrates that plasma volume loss during ultrafiltrative fluid removal is reconstituted by mobilization of extravascular fluid, and that the rate of mobilization depends on dialysate osmolality. 7 subjects underwent 2 sessions of hemodialysis differing only in the NaCl concentration and osmolality of the dialysate, each session with ultrafiltration of fluid averaging about 1,800 ml over 3 h. Higher dialysate osmolality resulted in (1) less net decrease in plasma volume, -160 ml vs. -590 ml; (2) more mobilization of extravascular fluid, 1,670 ml vs. 1,150 ml, and (3) better control of hypotension. These results suggest that higher dialysate osmolality improves hypotension and dysequilibrium during hemodialysis by altering the movement between body fluid compartments and preserving normal hemodynamic mechanisms.

Adult↗