Name the following Arterial Blood Gas (ABG) values: pH 7.31, PaCO2 44, HCO3- 12

Choice A reason: Respiratory acidosis involves low pH and high PaCO2. Normal PaCO2 (44) and low HCO3- (12) point to metabolic acidosis, not respiratory, so this incorrect.

Choice B reason: Metabolic alkalosis has high pH and HCO3-. Low pH (7.31) and low HCO3- (12) rule this out, indicating metabolic acidosis, so this is incorrect.

Choice C reason: Low pH (7.31) and low HCO3- (12) with normal PaCO2 confirm metabolic acidosis, where acid accumulation lowers pH. This matches, making it the correct choice.

Choice D reason: Respiratory alkalosis has high pH and low PaCO2. Low pH and normal PaCO2 exclude this, pointing to metabolic acidosis, so this is incorrect.

Choice A reason: NPH insulin is not mixed with insulin glargine, as glargine’s pH and formulation cause precipitation or altered pharmacokinetics when combined. NPH can be mixed with regular insulin, as they are compatible, making this choice incorrect for the patient’s reported practice.

Choice B reason: NPH and regular insulin are compatible and routinely mixed in one syringe to provide both intermediate and short-acting coverage. They don’t react chemically or lose efficacy when combined properly, making this choice incorrect, as mixing is a standard practice in diabetes management.

Choice C reason: Mixing NPH and regular insulin does not increase potency; it combines their pharmacokinetics for basal and prandial glucose control. The mixture delivers the additive effects of each insulin’s profile without enhancing overall potency, making this choice inaccurate for their combined action.

Choice D reason: Mixing NPH (intermediate-acting) and regular insulin (short-acting) is an accepted practice to manage type 1 diabetes with one injection, covering basal and prandial needs. Proper technique (drawing regular insulin first) ensures stability, making this the correct choice for the patient’s reported insulin administration.