Professional and Linguistic Assessments Board (PLAB) Practice Exam

What is the appropriate fluid replacement for a patient with DKA and blood pressure less than 90?

1. 0.45% NaCl 10-15 mins

2. 5% dextrose

3. 0.9% NaCl 10-15 mins

4. Lactated Ringer's Solution

The correct answer is: 0.9% NaCl 10-15 mins

In the context of diabetic ketoacidosis (DKA), appropriate fluid replacement is critical for managing the patient's condition, particularly if the blood pressure is low (less than 90 mmHg). The main goal in treating DKA is to restore volume status and improve circulation. Using 0.9% NaCl, or normal saline, is considered the standard initial treatment for fluid resuscitation in cases of DKA accompanied by hypotension. This isotonic solution helps restore intravascular volume, which can help improve blood pressure and perfusion. The infusion of normal saline is effective in diluting the circulating ketones and aiding renal function, facilitating the excretion of excess glucose and ketones. In contrast, other options are less suitable due to their specific properties. For example, 0.45% NaCl may not provide sufficient volume expansion due to its hypotonic nature, potentially worsening the patient’s hemodynamic status. Similarly, 5% dextrose is not appropriate at this stage since providing glucose could worsen the hyperglycemia and ketosis that are characteristic of DKA. Lactated Ringer's Solution can be beneficial for fluid replacement in other contexts but may not be the first choice in DKA management due to the need