Basic Concepts of Fluid and Electrolyte Therapy

Definition
AKI is a result of a rapid fall in glomerular filtration rate occurring
over hours or days. The consequences include a failure to regulate
fluid and electrolyte balance and a failure to excrete metabolic waste
products and drugs.
AKI is defined when one of the following criteria is met;
Serum creatinine rises by ≥26 µmol/l within 48 hours or
Serum creatinine rises ≥1.5 fold from a baseline value measured
within the previous week or
Urine output is 6 consecutive hours
If serum creatinine concentration has not been measured in the previous
week, use the most recent creatinine concentration measured
within the last three months. AKI can be staged according to the
criteria in Table 19.
Table 19: Stages of acute kidney injury
Stage Serum creatinine (SCr) criteria Urine output criteria
1
increase ≥26 µmol/l within 48 h or
increase ≥1.5-1.9 × baseline SCr
6 consecutive h
2 increase ≥2-2.9 × baseline SCr 12 h
3
increase ≥3 × baseline SCr or
increase ≥354 µmol/l
24 h
or anuria for 12 h
80