What is the expected pH change from too much liquid heparin in ABG samples?

When discussing the effect of excessive liquid heparin in arterial blood gas (ABG) samples, it is important to recognize that heparin is an anticoagulant that can alter the composition of the sample. Heparin itself can lead to an increased concentration of hydrogen ions in the solution, which tends to lower the pH value. This decrease in pH reflects a more acidic environment.

In practice, if too much heparin is used while drawing the sample, it can lead to dilution of bicarbonate, which is a buffer that normally helps maintain a stable pH. Consequently, the oversaturation of heparin can result in a pH that decreases toward 7.0, indicating acidosis.

Therefore, the reasoning aligns with the expectation that excessive heparin affects the balance of acids and bases in the sample, leading to a decrease in pH and potentially skewing results from the ABG analysis.