Order: ceftriaxone 2 g in 100 mL of 0.9% NaCI (normal saline solution) over 30 minutes

Available: Macro drip set: 15 gtt/mL

Calculate the IV flow rate in gtt/min.

A) Gastric emptying time:
Gastric emptying time plays a significant role in drug absorption. The faster the stomach empties its contents into the small intestine, the quicker the drug can be absorbed. If gastric emptying is delayed, such as with certain diseases, medications, or conditions (like gastroparesis), drug absorption may be slowed. Conversely, rapid gastric emptying can lead to quicker absorption, potentially reducing the time the drug has to exert its effects.

B) Capillary walls with large spaces between cells:
Capillary permeability influences how easily a drug can pass from the bloodstream into tissues. If the capillary walls have large gaps, such as in certain areas of the body (e.g., in the liver or spleen), drugs can more easily move across the capillary membrane and be absorbed into the system.

C) Stability and solubility of the medication:
For a drug to be absorbed effectively, it must be stable in the body and soluble in bodily fluids. Drugs that are poorly soluble or unstable in the stomach may not be absorbed efficiently. For instance, medications that are lipophilic (fat-soluble) may require a carrier or special formulation (e.g., emulsions or nanoparticles) to aid in absorption, whereas hydrophilic drugs may face challenges crossing cell membranes without assistance.

D) Inspiratory effort:
Inspiratory effort does not directly affect the absorption of drugs. Inspiratory effort refers to the act of inhaling, which is more relevant to drugs administered via inhalation (e.g., inhalers or nebulizers). It affects how well the drug is delivered to the lungs but does not influence absorption in the gastrointestinal tract or other routes of administration.

E) Presence of food in the stomach or intestines:
Food in the stomach or intestines can either speed up or slow down drug absorption. Some drugs are absorbed better on an empty stomach because food can slow gastric emptying and alter the drug's solubility. On the other hand, certain medications (e.g., fat-soluble drugs) may require food for optimal absorption.

Given:

Ordered dose of Dopamine: 3 mcg/kg/min

Child's weight: 41.8 lbs

Concentration of Dopamine: 400 mg in 250 mL D5W

Step 1: Convert child's weight from pounds to kilograms:

1 pound (lb) = 0.453592 kilograms (kg)

Child's weight in kg = 41.8 lbs x 0.453592 kg/lb = 18.935 kg

Step 2: Calculate the total dose of Dopamine in mcg/min:

Total dose (mcg/min) = Ordered dose (mcg/kg/min) x Child's weight (kg)

Total dose (mcg/min) = 3 mcg/kg/min x 18.935 kg

Total dose (mcg/min) = 56.805 mcg/min

Step 3: Convert mcg to mg:

Total dose (mg/min) = Total dose (mcg/min) / 1000 mcg/mg

Total dose (mg/min) = 56.805 mcg/min / 1000 mcg/mg

Total dose (mg/min) = 0.056805 mg/min

Step 4: Calculate the total dose in mg/hr:

Total dose (mg/hr) = Total dose (mg/min) x 60 min/hr

Total dose (mg/hr) = 0.056805 mg/min x 60 min/hr

Total dose (mg/hr) = 3.4083 mg/hr

Step 5: Calculate the infusion rate in mL/hr:

Infusion rate (mL/hr) = Total dose (mg/hr) / Concentration (mg/mL)

Infusion rate (mL/hr) = 3.4083 mg/hr / (400 mg/250 mL)

Infusion rate (mL/hr) = 3.4083 mg/hr x (250 mL/400 mg)

Infusion rate (mL/hr) = 2.1301875 mL/hr

Step 6: Round to the nearest tenth:

Infusion rate (mL/hr) ≈ 2.1 mL/hr