From the Guidelines
Ketonuria post cardiac bypass is best managed by avoiding excessive ultrafiltration during cardiopulmonary bypass, as recommended by the international multidisciplinary perioperative quality initiative 1.
Management of Ketonuria
The management of ketonuria after cardiac bypass surgery involves a multifaceted approach to address the underlying metabolic stress and fasting state associated with the procedure.
- Ensuring adequate hydration with intravenous fluids, typically normal saline at 100-125 mL/hour, is crucial depending on the patient's cardiac status and fluid balance.
- Insulin therapy may be necessary if blood glucose levels are elevated, typically starting with a sliding scale insulin regimen or continuous insulin infusion at 0.05-0.1 units/kg/hour if glucose exceeds 180 mg/dL, as supported by studies on perioperative management of adult diabetic patients 1.
- Nutritional support should be initiated as soon as clinically appropriate, beginning with clear liquids and advancing to a cardiac diet as tolerated.
- Regular monitoring of blood glucose levels every 1-2 hours initially, then every 4-6 hours once stable, is essential to prevent hypoglycemia and hyperglycemia.
- Electrolyte replacement, particularly potassium, may be needed as insulin therapy can cause hypokalemia.
Underlying Cause of Ketonuria
Ketonuria results from increased fat metabolism during the catabolic state following surgery when the body shifts to using fat as an energy source, producing ketone bodies that are excreted in urine.
- The use of excessive ultrafiltration during cardiopulmonary bypass should be avoided, as it may increase the risk of postoperative acute kidney injury (AKI) 1.
- Most cases of ketonuria resolve within 24-48 hours with appropriate management of hydration, glucose control, and resumption of adequate nutrition.
- It is essential to balance the need for fluid management and glucose control to prevent complications and promote optimal recovery.
From the Research
Ketonuria Post Cardiac Bypass
- Ketonuria, or the presence of ketones in the urine, can be a concern after cardiac bypass surgery, particularly in patients with diabetes or those who are at risk of developing hyperglycemia 2.
- Studies have shown that good glycemic control is essential for patients undergoing coronary artery bypass graft (CABG) surgery, as it can reduce the risk of mortality and major complications 2.
- Insulin therapy, such as insulin glargine, can be effective in managing hyperglycemia and reducing the risk of ketonuria in patients after CABG surgery 3, 2.
- However, the use of insulin therapy must be carefully managed to avoid hypoglycemia, which can also be a significant risk for patients after CABG surgery 3, 2.
Glycemic Control and Ketonuria
- Glycemic control is critical for preventing ketonuria and reducing the risk of complications after CABG surgery 2.
- Studies have shown that patients who achieve good glycemic control after CABG surgery have lower rates of mortality and major complications 2.
- The use of insulin glargine, in particular, has been shown to improve glycemic control and reduce the risk of ketonuria in patients after CABG surgery 3.
- Additionally, combining insulin therapy with other interventions, such as exercise and meal planning, can also be effective in managing hyperglycemia and reducing the risk of ketonuria 4.
Special Considerations
- Patients with type 1 diabetes, such as the case reported in 5, may require special consideration when managing ketonuria after CABG surgery.
- The use of a ketogenic diet, which induces a state of ketosis, can be effective in managing seizures in patients with epilepsy, but must be carefully managed in patients with diabetes to avoid hyperglycemia and ketonuria 5.
- In such cases, the simultaneous use of insulin glargine and insulin aspart, along with careful monitoring of urine ketones, can be effective in managing hyperglycemia and reducing the risk of ketonuria 5.