A client presents to the Emergency department with a 4-day history of anorexia, abdominal pain and vomiting. An arterial blood gas (ABG) is drawn with these results pH 7.47(7.35-7.45), PaCO2 35mmHg (35-45mmHg), HCO3 31 mEq/L (22-26 mEq/L). How should the nurse interpret these results?

a. BNP 700pg/ml (<100pg/ml)

Rationale: B-type natriuretic peptide (BNP) is a biomarker used to diagnose and assess the severity of heart failure. Elevated BNP levels indicate increased ventricular stretch and fluid overload, both of which are indicative of worsening heart failure. A BNP level of 700pg/ml is significantly elevated compared to the normal range (<100pg/ml) and suggests acute exacerbation or decompensation of heart failure, requiring prompt intervention and management adjustment.

b. Chest x-ray shows cardiomegaly: While cardiomegaly on chest x-ray is indicative of heart failure, it is a diagnostic finding rather than an acute result requiring immediate intervention. It would be important to address but may not require urgent reporting unless accompanied by acute symptoms.

c. Hematocrit 35% (37-47%): A hematocrit of 35% falls at the lower end. While changes in hematocrit can indicate fluid volume status, this value alone does not indicate an urgent need for intervention or adjustment of therapy. It may warrant monitoring over time, but it is not an immediate concern.

d. Echocardiogram with ejection fraction of 60% (normal is 55-75%): An ejection fraction of 60% falls within the normal range and is not indicative of worsening heart failure. While it's essential to monitor ejection fraction in heart failure patients, this result alone does not suggest acute decompensation requiring immediate intervention.

Based on the expected changes in hyperventilation related to anxiety, option b (pH 7.47, PaCO2 25 mmHg, HCO3 26 mEq/L) is the most consistent with respiratory alkalosis, which occurs due to hyperventilation:

a. pH 7.49, PaCO2 36 mmHg, HCO3 31 mEq/L:

• The pH is higher than the normal range, indicating alkalosis.
• The PaCO2 is within the normal range (slightly elevated), which is unexpected in hyperventilation where PaCO2 is typically decreased.
• The HCO3 is elevated, indicating metabolic alkalosis, which is not typically associated with hyperventilation related to anxiety.

b. pH 7.47, PaCO2 25 mmHg, HCO3 26 mEq/L:

• The pH is higher than the normal range, indicating alkalosis.
• The PaCO2 is below the normal range, indicating respiratory alkalosis, which is consistent with hyperventilation.
• The HCO3 is within the normal range, which can occur as a compensatory mechanism for respiratory alkalosis.

c. pH 7.32, PaCO2 41 mmHg, HCO3 22 mEq/L:

• The pH is lower than the normal range, indicating acidosis.
• The PaCO2 is within the normal range, which is unexpected in hyperventilation where PaCO2 is typically decreased.
• The HCO3 is within the normal range, indicating compensated metabolic acidosis, which is not typically associated with hyperventilation related to anxiety.

d. pH 7.30, PaCO2 48 mmHg, HCO3 26 mEq/L:

• The pH is lower than the normal range, indicating acidosis.
• The PaCO2 is elevated, indicating respiratory acidosis, which is not typically associated with hyperventilation.
• The HCO3 is within the normal range, which can occur as a compensatory mechanism for respiratory acidosis.