THE EFFECT OF POLYETHYLENE-GLYCOL GAVAGE ON PLASMA-VOLUME

This study examines the hypothesis that whole gut irrigation with poly ethylene glycol-electrolyte gavage solution (PEG-ELS) increases intrav ascular volume. Seventeen patients drank 6 to 8 liters of PEG-ELS in p reparation for elective colonoscopy. The patients were weighed and ser um electrolytes, albumin, hematocrit, blood urea nitrogen, and creatin ine were obtained prior to the gavage and 8 hr following gavage. Plasm a volume was measured before and after gavage using an isotope dilutio n technique involving I-125-human serum albumin. No patients developed symptoms of intravascular volume excess or depletion following gavage . There was no significant change in body weight, serum sodium, chlori de, potassium, bicarbonate, blood urea nitrogen, or creatinine followi ng gavage with PEG-ELS. When measured by the isotope dilution techniqu e, the mean plasma volume increased from 3174 +/- 117 ml before gavage to 3365 +/- 160 ml following gavage (P = 0.03). This represented a me an percentage change in plasma volume of 5.88 +/- 2.4%. The percentage change in plasma volume associated with gavage ranged from -9.8 to +2 9.8%. This data supports the hypothesis that gavage with polyethylene glycol-electrolyte solution is associated with an increase in plasma v olume. Although in most patients the increase in plasma volume is mini mal, there is significant variability in this response, with some pati ents experiencing substantial increases in plasma volume. (C) 1994 Aca demic Press, Inc.