Intravenous infusions, dose volume/rates

TABLE 38.11 Repeated intravenous infusion dose volumes/rates (and possible maximal volumes/rates)... 

Treatment of sodium overload consists of administration of loop diuretics to facilitate excretion of the excess sodium, as well as intravenous D5W. The latter should be infused at a rate that will decrease the serum sodium at approximately 0.5 mEq/L per hour, or 1 mEq/L per hour in cases in which the hypernatremia developed rapidly over several hours. ° The volume of infusate may be estimated as described previously. Furosemide should be administered at a dose of 20 to 40 mg intravenously every 6 hours. 

The immediate management of patients with acute adrenal insufficiency includes intravenous therapy with isotonic sodium chloride solution supplemented with 5% glucose and corticosteroids and appropriate therapy for precipitating causes such as infection, trauma, or hemorrhage. Because cardiovascular function often is reduced in the setting of adrenocortical insufficiency, the patient should be monitored for evidence of volume overload such as pulmonary edema. After an initial intravenous bolus of 100 mg, hydrocortisone (cortisol) should be given by continuous infusion at a rate of 50-100 mg every 8 hours. At this dose, which approximates the maximum daily rate of cortisol secretion in response to stress, hydrocortisone overwhelms the 11/1HSD2 barrier in mineralo-corticoid-responsive tissues and has sufficient mineralocorticoid activity to meet all requirements. As the patient stabilizes, the hydrocortisone dose may be decreased to 25 mg every 6-8 hours. Thereafter, patients are treated in the same fashion as those with chronic adrenal insufficiency see below). 

Administration - The loading dose of aminophylline can be given by very slow IV push or, more conveniently, may be infused in a small guantity (usually 100 to 200 mL) of 5% Dextrose Injection or 0.9% Sodium Chloride Injection. Do not exceed the rate of 25 mg/min. Thereafter, maintenance therapy can be administered by a large volume infusion to deliver the desired amount of drug each hour. Aminophylline is compatible with most commonly used IV solutions. Oral therapy should be substituted for intravenous aminophylline as soon as adeguate improvement is achieved. 

Initial dose—Administer intravenously at 15 mg Ig per kg body weight per hour. If no adverse reactions occur after 30 minutes, the rate may be increased to 30 mg Ig/kg/hr if no adverse reactions occur after a subsequent 30 minutes, then the infusion may be increased to 60 mg Ig/kg/hr (volume not to exceed 75 ml/hour). DO NOT EXCEED THIS RATE OF ADMINISTRATION. The patient should be monitored closely during and after each rate change. 

Following an intravenous injection of 10 mg propranolol, McAllister (1976) found the values of the elimination rate constant (K) and the apparent volume of distribution (V) to be 0.00505 0.0006min and 295 SSL, respectively (mean SD for six patients). These values were then used to calculate the loading dose (I ) and infusion rate (Q) necessary to instantly obtain and then continuously maintain propranolol plasma concentrations of 12, 40 and 75 ngmL . ... 

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