Monitoring of fluid volume status involves frequent measurements of vital signs (including monitoring for orthostatic changes in blood pressure and heart rate), lung assessment, and monitoring of intake and output. Initial urine output lags behind IV fluid intake as dehydration is corrected. Plasma expanders may be necessary to correct severe hypotension that does not respond to IV fluid treatment. Monitoring for signs of fluid overload is especially important for patients who are older, have renal impairment, or are at risk for heart failure. Restoring Electrolytes The major electrolyte of concern during treatment of DKA is potassium. The initial plasma concentration of potassium may be low, normal, or high, but more often than not, tends to be high (hyperkalemia) from disruption of the cellular sodium-potassium pump (in the face of acidosis). Therefore, the serum potassium level must be monitored frequently. Some of the factors related to treating DKA that affect potassium concentration include rehydration, which leads to increased plasma volume and subsequent decreases in the concentration of serum potassium. Rehydration
also leads to increased urinary excretion of potassium. Insulin administration enhances the movement of potassium from the extracellular fluid into the cells. Cautious but timely potassium replacement is vital to avoid dysrhythmias that may occur with hypokalemia. As much as 40 mEq per hour may be needed for several hours. Because extracellular potassium levels decrease during DKA treatment, potassium must be infused even if the plasma potassium level is normal. Frequent (every 2 to 4 hours initially) ECGs and laboratory measurements of potassium are necessary during the first 8 hours of treatment. Potassium replacement is withheld only if hyperkalemia is present or if the patient is not urinating. Quality and Safety Nursing Alert Because a patient’s serum potassium level may drop quickly as a result of rehydration and insulin treatment, potassium replacement must begin once potassium levels drop to normal in the patient with DKA. Reversing Acidosis Ketone bodies (acids) accumulate as a result of fat breakdown. The acidosis that occurs in DKA is reversed with insulin, which inhibits fat breakdown, thereby ending ketone production and acid buildup. Insulin is usually infused IV at a slow, continuous rate (e.g., 5 units per hour). Hourly blood glucose values must be measured. IV fluid solutions with higher concentrations of glucose, such as NS solution (e.g., D 5 NS, D 5 .45NS), are given when blood glucose levels reach 250 to 300 mg/dL (13.8 to 16.6 mmol/L) to avoid too rapid a drop in the blood glucose level (i.e., hypoglycemia) during treatment. Regular insulin, the only type of insulin approved for IV use, may be added to IV solutions. The nurse must convert hourly rates of insulin infusion (frequently prescribed as units per hour) to IV drip rates. For example, if 100 units of regular insulin are mixed into 500 mL of 0.9% NS, then 1 unit of insulin equals 5 mL;
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- Spring '14
- Nursing, Blood sugar, DKA