Plasma Volume Expansion and Fluid Kinetics of 20% Albumin During General Anesthesia and Surgery Lasting for More Than 5 Hours

Abstract

BACKGROUND: Intraoperative administration of crystalloid for plasma volume expansion may be reduced by use of hyperoncotic albumin. However, the degree of plasma volume expansion with administration of 20% albumin is poorly quantitated. We estimated the amount of volume expansion attributable to 20% albumin administration in patients undergoing surgery for more than 5 hours. METHODS: Twenty percent albumin was delivered at 3 mL/kg by intravenous infusion during 30 minutes to 15 patients (mean ± standard deviation [SD] age; 46 ± 15 years) undergoing surgery. Blood samples and urine were collected for 5 hours. Mass balance calculations and volume kinetics were used to estimate plasma volume expansion and capillary leakage of albumin and fluid. RESULTS: Administration of 20% albumin was associated with an increase in plasma volume amounting to 1.7 times the infused volume. After correction for hemorrhage, the median (and 25th to 75th percentiles) intravascular half-life for the administered albumin mass was 20.4 (14.2-34.7) hours. The plasma volume decreased with a half-life of 21.7 (16.1-26.8) hours. Urinary excretion was 3 times greater than the infused volume of albumin, but kinetic analysis suggested that other flows of fluid to and from the plasma occurred more slowly than previously found in volunteers. Hemodynamic support with norepinephrine increased urinary excretion and contracted the plasma volume. CONCLUSIONS: Albumin (20%) increased the plasma volume by 1.7 times the infused volume. Our results do not support that the transcapillary leakage of albumin is accelerated by anesthesia and surgery. (Anesth Analg 2022;134:1270-9) KEY POINTS• Question: What is the magnitude of plasma volume expansion with intravenous administration of 20% albumin during surgery? • Findings: The plasma volume increased by 1.7 times the infused volume of 20% albumin in patients undergoing surgical procedures lasting more than 5 hours. • Meaning: Twenty percent albumin increases plasma volume by more than the infused volume during lengthy surgery. GLOSSARYASA = American Society of Anesthesiologists; BW = body weight; CI = confidence interval; CONSORT = Consolidated Standards of Reporting Trials; COP = colloid osmotic pressure; CRP = C-reactive protein; CV = coefficient of variation; EDTA = ethylenediaminetetraacetic acid; FOCE ELS = First Order Conditional Estimation Extended Least-Squares; Hgb = hemoglobin; IV = intravenous; k 10 = elimination rate constant for albumin or fluid leaving the kinetic system; k 21 = rate constant for absorption of fluid for the extravascular (interstitial) fluid space to V c ; k b = fluid eliminated from the kinetic system but not recovered as urine; k bleed = rate constant for plasma loss with hemorrhage and blood sampling; MAP = mean arterial pressure; NLME = nonlinear mixed effect; NT-proBNP = aminoterminal prohormone brain natriuretic peptide; R 0 = rate of infusion; SD = standard deviation; Spo 2 = peripheral capillary oxygen saturation; STROBE = Strengthening the Reporting of Observational Stud...

Plasma disappearance rate of albumin when infused as a 20% solution

“…The first group of surgical patients received 20% albumin over 30 min but no other fluid during the operation, and major hemorrhage was rare (median albumin loss 13 g, range 5–39) [ 11 ]. The second group of surgical patients suffered a larger hemorrhage that contained 30 g (mean, SD 11 g) of albumin; they were also given Ringer’s lactate continuously in addition to the standard infusion of 20% albumin over 30 min [ 12 ].…”

“…The present report is a secondary publication to four publications in which 3 mL/kg of 20% albumin (approximately 200 mL) was administered over 30 min at a constant rate by an infusion pump to 70 subjects in the following clinical settings: healthy volunteers ( N = 15) [ 9 ], post-burn patients ( N = 15) [ 10 ], ongoing surgery with minor blood loss ( N = 15) [ 11 ], ongoing surgery with major bleeding ( N = 10) [ 12 ], and postoperative patients ( N = 15) [ 9 ]. Reporting adhered to the STROBE checklist.…”

“…The study of ongoing elective surgery with minor blood loss recruited patients scheduled for surgery lasting for at least 5 h but without an expected major hemorrhage. Exclusion criteria were age < 18 years, poor health status (American Society of Anesthesiologist´s [ASA] Classes III-IV), severe allergy, kidney failure or heart failure [ 11 ].…”

“…Chronic medications were tamoxifen ( N = 3) and goserelin ( N = 1) to treat breast cancer, and sumatriptan ( N = 1) for migraine. General anesthesia without additional epidural analgesia was used as described in the original report [ 11 ]. A slow drip (0.5 mL/kg/h) of glucose 2.5% with electrolytes compensated for evaporation during the procedure.…”

“…The present study focuses on an excess amount of albumin provided between Time 0 and Time t on top of the pre-existing intravascular albumin. However, the there is a mis-match between the change in the plasma albumin concentration (∆ P -albumin t−0 ) and the intravascular albumin mass because 20% albumin attracts extravascular fluid by means of its high oncotic pressure [ 9 – 11 ]. This mismatch is accounted for by multiplying ∆ P -albumin t−0 by the plasma dilution ( P -dilution) at time t : …”