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M Spongano

Publications and source records attributed to M Spongano.

24 records · Page 2Linked to original sources
PubMed1987

Effects of pK variability on bicarbonate balance evaluation in dialysis patients.

Bicarbonate balance is usually calculated from the Henderson-Hasselbalch equation under the assumption that pK is constant. To evaluate the pK variability and its effects on bicarbonate computed with autoanalyzers in dialysis patients, we studied 44 patients on maintenance hemodialysis. The pH, PCO2, total CO2, and pK were determined in each patient before and after the dialysis session. The mean total CO2 calculated (22.5 +/- 2.7 meq/L) from pH and PCO2 values was significantly higher (p less than 0.001) than that directly measured (20.4 +/- 3.0 meq/L) with total CO2 analyzer. The mean (+/- SD) pK value was 6.14 +/- 0.06 (range 6.05-6.28). The percentage error in computed bicarbonate due to pK variations from the traditional pK value of 6.1 ranged between -11% and 52%. The pK value changed during dialysis in the majority of our patients, thereby confirming that pK consistency does indeed vary. Thus, investigation of acid-base balance based on pH and PCO2 determination may lead to erroneous results determined by pK abnormalities.

Acid-Base Equilibrium↗
PubMed1985

Failure of naloxone in reversal hemodialysis-induced hypotension.

In 5 uremic patients the role of opioid peptides in dialysis-induced hypotension was investigated through the administration of naloxone. An intravenous bolus injection of 1 mg of naloxone was administered immediately before starting a routine hemodialysis session and was repeated when the patients' systolic arterial pressure sank below 90 mm Hg. In our patients, naloxone had no effect on the resting arterial pressure or on dialysis-induced hypotension.

Blood Pressure↗
PubMedDate not supplied

Automatic control of blood volume trends during hemodialysis.

Dialysis induced hypovolemia plays an important role in triggering intradialytic hypotension. The authors developed an automatic system (BVAC) with feedback changes in the ultrafiltration rate (UFR) and dialysate conductivity (DC) to match blood volume (BV) intradialytic profiles with the desired trajectories. The system consists of three subunits: (1) an optical probe to continuously detect the BV changes derived from hemoglobin changes, and (2) a dialysis machine interfaced with (3), a personal computer in which a time-dependent model is implemented. The model is based on a dynamic regulator that can set the actual BV changes against the corresponding desired values. Any discrepancy is offset by changes in UFR and DC. To verify the efficacy of the BVAC system in reducing intradialytic cardiovascular instability, five hypotension-prone patients were studied during a three period protocol (A1-B-A2) that lasted six sessions per period per patient. During periods A1 and A2, the dialysis procedure was conventional hemodialysis (HD) with linear UFR and constant DC. During period B, both UFR and DC were automatically regulated by the BVAC system. Mean BV reduction and its variability were lower during period B than during periods A1 and A2 (-10.2%, -11.3%, and -11.5, respectively). Episodes of hypotension were significantly (P < 0.05) fewer during period B (n = 1) than during periods A1 (n = 8) and A2 (n = 5). The therapeutic interventions defined as infused milliliters of isotonic and hypertonic solution were fewer during period B compared with periods A1 and A2. Total UF and end-dialysis plasma sodium concentrations did not differ in the three study periods. BVAC was effective in improving cardiovascular tolerance to treatment.

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