Question

an anesthesiologist has ordered 1.2 \\(\frac{mg}{kg}\\) of iv midazolam for a 99.0 kg patient about to have a surgical procedure. the drug is to be delivered over 30 min. a 250. ml iv bag of normal saline in which 1.00 g of midazolam has been dissolved is available. to what infusion rate should the iv pump be set? round your answer to the nearest \\(\frac{ml}{h}).

Explanation:

Step1: Calculate the total amount of midazolam needed

The patient's weight is 99.0 kg and the ordered dose is 1.2 mg/kg. So the total amount of midazolam needed is $99.0\times1.2$ mg.
$99.0\times1.2 = 118.8$ mg

Step2: Determine the concentration of the midazolam - saline solution

There is 1.00 g (1000 mg) of midazolam dissolved in 250 mL of normal - saline. So the concentration $C=\frac{1000}{250}$ mg/mL.
$C = 4$ mg/mL

Step3: Calculate the volume of the solution needed

Using the formula $V=\frac{m}{C}$, where $m$ is the mass of the drug and $C$ is the concentration. Substitute $m = 118.8$ mg and $C = 4$ mg/mL.
$V=\frac{118.8}{4}=29.7$ mL

Step4: Adjust for the time of infusion

The drug is to be delivered over 30 min (0.5 h). To find the infusion rate $R$ in mL/h, use the formula $R=\frac{V}{t}$, where $V$ is the volume and $t$ is the time in hours.
$R=\frac{29.7}{0.5}=59.4\approx59$ mL/h

Answer:

59 mL/h