Case 3: Fluid Volume Calculations


Maintenance = [(30 x 4.1) + 70] = 193 ml/day

Replacement of dehydration deficit:

English Calculation
0.05 x 9 lb = 0.45 lb of weight loss from dehydration
0.45 lb x 454 ml/lb = 204 ml

OR

Metric Calculation
0.05 X 4.1 X 1000 = 205 ml
Correction of 80% of dehydration deficit in the first 24 hours:
0.80 x 205 ml = 163 ml

Total fluid requirement for dehydration plus daily maintenance for the first 24 hours:

193 ml + 163 ml = 356 ml (approximately 14.8 ml/hour)

In this case dehydration should be corrected more rapidly (8 hours) than normal to prevent further renal damage and to differentiate prerenal azotemia (physiological oliguria) from pathological oliguria.  Thus, the fluid plan would go as follows:

First 8 Hours:

193/3 = 62 mls for maintenance

PLUS

163 ml for deficit volume

Total volume = 62 + 163 = 225 ml or 28.1 ml/hour

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