Emergency fluid management for hypovolemia.

Emergency fluid resuscitation of hypovolemic patients begins with an accurate assessment of the degree of volume depletion as well as identification of the cause and associated abnormalities. On the basis of this information, the proper resuscitative fluid can be chosen and administered by the appropriate route, as guided by the urgency of the situation. Patients with severe volume depletion and those in shock require intravenous fluids. In other situations, oral rehydration is often appropriate. Specific fluids then can be tailored to the individual patient's needs and adjusted as warranted by ongoing monitoring.

Is 8 hours of nightly peritoneal dialysis enough?

Eight hours of nightly tidal peritoneal dialysis (TPD) theoretically can provide uremia control equal that of continuous cyclic peritoneal dialysis (CCPD). To assess the in vivo validity of this prediction, six patients underwent mass transfer area coefficient (MTaC) measurements and dialysis using CCPD and TPD. CCPD consisted of five nighttime exchanges of 40 ml/kg and a daytime exchange of 20 ml/kg. TPD used an initial fill of 40 ml/kg and hourly tidal flows of 30 or 50 ml/kg. The nocturnal portion of CCPD lasted 9.7 hr (range 9.5-10 hr). TPD lasted 8.5 hr (range 8-9 hr) and was devoid of daytime dialysis. The patients consumed a diet containing 1.2 +/- 0.07 g protein/kg body weight (range 0.7-1.7 g/kg) and had a pre dialysis blood urea nitrogen concentration of 52 mg/dl (range 18-82 mg/dl). The dialysate clearances of urea and creatinine were indexed to patient size and extrapolated to weekly values. CCPD provided a weekly creatinine clearance of 50 L/1.73 m2 and a Kt/Vurea of 2.06. TPD with an hourly dialysate flow of 30 ml/kg achieved a weekly creatinine clearance of 42.8 L/1.73 m2 and a Kt/Vurea of 1.73. When the hourly dialysate flow was increased to 50 ml/kg, these values improved to 53.3 L/1.73 m2 and 2.15, respectively. Dialysis efficiency equal to that of CCPD can be obtained using 8 hr of TPD when membrane characteristics (mass transfer area coefficient) and dialysate flow rates are appropriate. Patients with normal or above normal mass transfer area coefficients can obtain a weekly Kt/Vurea exceeding 2.0 using nightly high flow TPD.

Tidal peritoneal dialysis: kinetics and protein balance.

Some patients find automated peritoneal dialysis preferable to continuous ambulatory peritoneal dialysis (CAPD). Unfortunately, automated peritoneal dialysis prescriptions are time consuming and can impede rehabilitation. We wished to determine whether an 8-hour tidal peritoneal dialysis (TPD) prescription could maintain the time averaged blood urea nitrogen at 60 mg/dL or less while patients consumed a diet containing approximately 1.2 g protein/kg body weight/d. Ten home dialysis patients previously stabilized on continuous cyclic peritoneal dialysis volunteered for a metabolic balance study conducted at the University of Iowa's Clinical Research Center. A peritoneal equilibration test was conducted and mass transfer area coefficients (MTaCs) were derived for each subject. Nitrogen balance was measured during the last 5 days of a 12-day constant diet while patients underwent a series of monitored nocturnal dialyses. Mass transfer area coefficient measurements were reproducible and independent of the filling volume and ultrafiltration, but varied between subjects (normalized MTaCurea = 33.6 +/- 16.3 mL/min, normalized MTaCcrt = 16.3 +/- 9.5 mL/min). Tidal peritoneal dialysis urea and creatinine clearances could be predicted by these MTaC values (r2 = 0.70 urea, r2 = 0.91 creatinine). Nitrogen balance assumptions predicted, and we confirmed, a relationship between dietary protein intake and urea nitrogen generation (r2 = 0.82) during TPD. A normalized protein catabolic rate of 1.2 g/kg/d resulted in a urea nitrogen generation rate of approximately 100 mg/kg/d. If a patient's protein intake was approximately 1.2 g/kg/d, then TPD with a weekly urea clearance normalized to body volume (Kt/V(urea)) of approximately 2.1 (urea clearance, approximately 0.35 mL/kg/min) could maintain a time averaged blood urea nitrogen of approximately 60 mg/dL.(ABSTRACT TRUNCATED AT 250 WORDS)