A renal consult was called because he developed metabolic alkalosis with the following laboratory results:
Na-126 K-5.0 Cl-87 CO2-38 BUN-17 Creat-0.58 Glucose-119
Ca-8.4 Phos-2.6 Urate-2.8 Alb-2.8
ABG:pH-7.53 pO2-67 pCO2-48
ALT-61 AST-52 Alk phos-150
Hgb-8 Hct-25 WBC-7.5 Plts-28
The chest xray showed severe bilateral airspace disease consistent with pulmonary edema.
What is the acid base abnormality and why?
It is clear that this patient had metabolic alkalosis with relatively appropriate respiratory compensation, depending on how closely correlated these laboratory tests are in time.
Metabolic alkalosis is a relatively common clinical problem, most often induced by diuretic therapy, or the loss of gastric secretions due to vomiting or nasogastric suction.
Two separate abnormalities can contribute to metabolic alkalosis:
- An elevation in the plasma bicarbonate concentration due to hydrogen loss in the urine or gastrointestinal tract, hydrogen movement into the cells, the administration of bicarbonate, and contraction alkalosis.
- A decrease in net renal bicarbonate excretion.
Metabolic alkalosis has been described:
- The infusion of more than eight units of bank blood (anticoagulated with citrate).
- Observed when citrate rather than heparin was used as an anticoagulant in hemodialysis
- Continuous renal replacement therapy (CVVHD) with citrate.
- Extensive use of crack cocaine (which contains significant amounts of an alkali) in dialysis patients.
- Fresh frozen plasma as a replacement fluid during plasmapheresis.