Relationship Between Potassium Level in Venous Blood Samples Drawn and Heel Sticks In Infants and Newborns

This is a prospective study which will take place at the Children's Memorial Hermann
Hospital Operating Room.

After obtaining written informed consent from parents or guardians, infants and babies
scheduled to have elective surgery under routine general anesthesia and are <6 months of age
will be included in the study. After the baby receives routine general anesthesia, a small
amount of blood, 0.5 ml, will be drawn from a vein when an I.V. is started for the surgery.
The largest possible cannula will be placed whenever possible to decrease hemolysis. If a
baby has a central line, the blood sample will be drawn from it. If a baby has an existing
peripheral I.V., a blood sample will be drawn from the I.V. cannula only if blood is freely
running, to avoid hemolysis.

Blood will be placed into a heparinized, 1 ml syringe for venous blood gas analysis. A
second blood sample, 0.3 ml, will be drawn into a capillary pipette from a heel stick for
capillary blood gas analysis. The heel will be properly sterilized, and a proper size lancet
will be used. The same operator will be performing the heel stick in each case.

Inclusion Criteria:

- Infants and babies, ASA physical Status I-III, less than 6 month of age and scheduled
to have elective surgery under routine general anesthesia at Children's Memorial
Hermann Hospital will be included.

Exclusion Criteria:

- Babies and infants with documented anemia (< 8 gm), who are bleeding, ASA
Classification >III, have sickle cell disease or trait, thalassemia, HIV or DIC will
be excluded from the study. Babies with organ failure will be excluded.