Glycemic Control - Diabetes Mellitus

Glycemic Control - Diabetes Mellitus

1. Glycemic control Ni’ma bader

2. DM Definition: is a group of metabolic disorders characterized by hyperglycemia and abnormalities in carbohydrate, fat, and protein metabolism. Complications: microvascular and macrovascular complications.

3. Type 1 DM Type 2 DM Speed of o nset Abrupt Gradual Age of onset Mostly young Mostly adults Body type Thin or normal Often obese Autoantibodies Present Absent Endogenous insulin Absent Decrease gradually Symptoms Symptomatic Often asymptomatic

4. Treatment approach Patients with HbA lc of 7.5% or less are usually treated with an antihyperglycemic agent which is unlikely to cause hypoglycemia. Those with HbA lc more than 7.5% but less than 8.5% could be initially treated with a single agent, or combination therapy. Patients with higher initial HbA lc will require two agents or insulin.

5. Insulin should be particularly considered in A1C >9.5 percent ,fasting plasma glucose >250 mg/ dL random glucose consistently >300 mg/ dL . Symptomatic patients may initially require treatment with insulin or combination therapy. if the individualized A1C target is not reached after 3 months of dual-drug therapy, a third drug may be added.

6. ICU patients

7. BG target range Definition of hyperglycemia: BG>140mg/Dl Treat if BG>180mg/ dL Target BG: 140–180 mg/ dL Patients with trauma , traumatic brain injury, cardiothoracic surgery, and thermal injury may benefit from tighter BG (e.g., less than 140–150 mg/ dL ) control if it can be done safely without hypoglycemia.

8. BG monitoring frequency With insulin infusions: Monitor BG every hour then extend it to every 2 hours once there is stability in BG control and the intravenous insulin infusion rate is demonstrated . BG monitoring could be extended to every 4 hours once two consecutive BG concentrations in the target range are achieved. If the patient stable enough to warrant BG monitoring every 4 hours, the EN-fed patient is transitioned to intermediate- or long acting subcutaneous insulin therapy

9. Point-of-care meters Point-of-care meters with capillary BG testing may be reasonable for most critically ill patients and still in use by many institutions as long as the patient’s BG concentrations are greater than 80 mg/ dL the vast majority of the time. For low BG concentrations, point-of-care meters may erroneously report BG concentrations higher than measured. Patients with significant peripheral edema may also have erroneous BG concentrations

10. Transitioning from a continuous intravenous insulin infusion Give 30%–50% of the daily required intravenous regular human insulin, divided into two separate doses and given every 12 hours. Continue the graduated intravenous insulin infusion according to the algorithm. BG measurements are continued every 1–2 hours and are mapped to the timing of the subcutaneous NPH therapy to ascertain its pharmacokinetic peak and duration. The NPH dosage and interval are adjusted accordingly daily until the intravenous regular human insulin infusion is “auto-weaned” to 1–2 units/hour . The regular human insulin infusion is then discontinued with BG determinations, with slidingscale regular human insulin coverage every 3–4 hours. The NPH is further titrated daily according to the required amount of corrective regular human insulin required to maintain BG within the target BG range. Frequency of BG measurements is decreased because the patient has stability in glycemic control.

11. Case: Patient Case 14. A 55-year-old woman (weight 75 kg) without diabetes is given PN after a major GI resection. She has been weaned from mechanical ventilation and is being transferred from the ICU to the floor. Her current PN formulation is 200 g of dextrose (1.8 mg/kg/minute), 110 g of amino acids, and 80 g of lipids (1.1 g/kg/day), which meets her goal requirements of protein at 26 kcal/kg/day and 1.5 g/kg/day. It contains regular human insulin at 20 units/day. During the past 24 hours, her fingerstick BG measurements have been 170–210 mg/ dL , and her serum glucose concentration is 182 mg/ dL . She has received 14 units of sliding-scale regular human insulin coverage. Which would be best to suggest for optimal glycemic control? A . Increase regular insulin to 30 units/day. B . Decrease dextrose to 100 g/day. C . Increase regular insulin to 50 units/day. D . Do not change the current regimen

12. Diabetic emergencies Diabetic ketoacidosis (DKA) Hyperosmolar hyperglycemic state (HHS )

13. Causes: Typically caused by an insufficiency of insulin in patients with diabetes combined with another potential trigger such as infection, pancreatitis, and certain drugs (steroids, diuretics, vasopressors, antipsychotics, cocaine).

14. DKA HHS DM type Type 1 Type 2 BG >250mg/ dL >600mg/ dL Bicarb. Decreased Increased Blood PH Acidemia (PH<7.3) PH>7.3 Ketones Ketonuria No ketonuria Others Increased anion gap Increased serum Osmolarity

15. Management: Fluid replacement: 0.9 % sodium chloride at a rate of 15–20 mL/kg for the first hour. Thereafter , fluid administration is titrated to hemodynamic parameters and urine output. Patients with mild dehydration and normal or high sodium concentrations can be changed to 0.45% sodium chloride infused at a rate of 250–500 mL/hour. Maintenance fluids can be switched to a dextrose-containing fluid (often 5% dextrose with 0.45% sodium chloride) once BG concentrations have dropped to less than 200 mg/ dL in DKA and less than 300 mg/ dL in HHS.

16. 2. Insulin therapy Intravenous regular insulin is preferred to subcutaneous insulin because of its short half-life and ease of titration. The insulin infusion should subsequently be titrated on an hourly basis to decrease BG concentrations by 50–75 mg/ dL /hour.

17. Potassium should be replaced aggressively (assuming adequate renal function) with a goal serum potassium of 4–5 mEq /L. Patients with initial serum potassium less than 3.3 mEq /L should have insulin withheld and potassium administered until their serum potassium is above 3.3 mEq /L. Patients with serum potassium of 3.3–5.2 mEq /L should have 20–30 mEq of potassium added to each liter of intravenous fluid administered. Patients with initial serum potassium greater than 5.2 mEq /L should not receive potassium, but they should be monitored closely (with potassium administered if the patient’s serum falls below 4 mEq /L ). Patients with DKA and initial hyperkalemia should not receive therapy directed toward total body potassium removal (e.g., sodium polystyrene sulfonate or furosemide). The patient’s serum potassium will typically decrease as insulin is administered.

18. Acidemia: Administer sodium bicarbonate if PH<6.9

19. Hypoglycemia Definition: BG less than 70 mg/ dL Mild to moderate hypoglycemia: BG concentration of 40–60 mg/ dL (because autonomic symptoms often appear) Severe (life-threatening) hypoglycemia as less than 40 mg/ dL . Occurs commonly in the ICU, both with and without intensive glucose control. Symptoms: In the early stages: sweating , anxiety, hunger, palpitations, tremor. Confusion, dizziness, and difficulty speaking develop. Severe hypoglycemia leads to seizures and hypoglycemic coma.

20. Most common risk factors for hypoglycemia during insulin therapy Excessive insulin dose Abrupt discontinuation of EN or PN without an adjustment in the insulin therapy Renal failure (half-life of insulin is prolonged, impaired renal gluconeogenesis in response to hypoglycemia) Advanced age Inotropes , vasopressor agents, octreotide with insulin therapy Sepsis

21. Management For conscious patients without severe symptoms, oral glucose should be ingested (milk, juice, or dextrose tablets). The typical initial glucose dose is 20 g, which should be repeated in 15–20 minutes if symptoms have not improved or if BG remains low. Because the response to this “rescue glucose” is transient (less than 2 hours), it should be followed by more substantial glucose intake as a snack or meal.

22. Parenteral therapy is necessary for patients unable to take glucose orally or hospitalized patients with moderate or severe hypoglycemia.

23. Hospitalized patients with severe hypoglycemia (either severe symptoms or BG less than 40 mg/ dL ) or those receiving an insulin infusion with BG less than 70 mg/ dL (less than 100 mg/ dL in neurologic injured patients) should be treated with intravenous dextrose : Insulin infusion should be discontinued, as appropriate. Administer 10–20 g of 50% dextrose solution (20–40 mL of 50% dextrose in water). The BG measurement should be repeated in 15 minutes, with additional dextrose doses administered to achieve a BG greater than 70 mg/ dL . Care should be taken to avoid excessive dextrose administration in order to avoid iatrogenic hyperglycemia and because glucose variability has been associated with adverse outcomes.