"Spot" urine collections do not accurately represent 24-hour sodium excretion in surgically stressed children.
Deranged metabolism in posttraumatic or surgically stressed children makes fluid and electrolyte management difficult. Clear guidelines for salt and fluid administration have not been established. Recent management trends utilize four-hour and eight-hour "spot" urine collection measurement to imply 24-hour requirements. Six children, having suffered traumatic disease or surgical stress, were studied on an hourly basis for characterization of urinary sodium loss. Measured hourly values were combined to represent four-hour and eight-hour "spot" collections and then extrapolated to represent 24-hour losses. A great variation in sodium excretion was demonstrated on hourly samples; the variations were compounded by extrapolation. The extrapolated values varied from the measured hourly sodium losses by 0.66 to 123%. The four-hour extrapolations varied from measured values 14 to 198% (mean 55.2%). The eight-hour combinations varied 6.59 to 136% (mean 44.1%). On the basis of these data, we discourage the use of extrapolated values to imply 24-hour requirements. We support the use of a standard intravenous fluid (one-half strength normal saline or Ringer's lactate) with frequent urinary sodium determinations to individualize fluid and electrolyte management.
Department of Surgery, University of Texas Health Science Center, Houston.
E G
EG
Ford
L M
LM
Jennings
R J
RJ
Andrassy
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005440:Fluid Therapy; D006801:Humans; D007223:Infant; D008297:Male; D009318:Natriuresis; D011184:Postoperative Period; D012964:Sodium / Q000652:urine*; D013048:Specimen Handling / Q000379:methods; D013312:Stress, Physiological / Q000628:therapy / Q000652:urine*; D013997:Time Factors
D012964:Sodium