a. The client's weight is 50 kg, and the Dobutrex solution is ordered to titrate between 2.5 and 5 mcg/kg/min. To determine the flow rate setting for a volumetric pump, we need to calculate the dosage range in mg/min.
Dosage range = weight (kg) x titration range (mcg/kg/min) x 60 (min/hr) x 0.001 (mcg to mg conversion factor)
Dosage range = 50 x (2.5 to 5) x 60 x 0.001
Dosage range = 7.5 to 15 mg/min
To calculate the flow rate setting, we need to divide the dosage range by the concentration of the Dobutrex solution, which is 250 mg/500 mL or 0.5 mg/mL.
Flow rate setting = dosage range (mg/min) / concentration (mg/mL)
Flow rate setting = 7.5 to 15 / 0.5
Flow rate setting = 15 to 30 mL/hr
Therefore, the flow rate setting for a volumetric pump should be set between 15 to 30 mL/hr.
b. If the IV flow rate is being maintained at 25 mL/hr after several titrations, we can calculate the dosage infusing per minute by multiplying the flow rate by the concentration of the Dobutrex solution and then dividing by the patient's weight.
Dosage infusing per minute = (IV flow rate (mL/hr) x concentration (mg/mL)) / weight (kg) x 60 (min/hr)
Dosage infusing per minute = (25 x 0.5) / 50 x 60
Dosage infusing per minute = 0.02 mg/min
Therefore, the dosage infusing per minute is 0.02 mg/min.