The flow rate of an intravenous drip is controlled by varying the number of drips of fluid delivered per unit time. A particular solution contains 6.2 g of sodium chloride per litre and must be administered at such a rate that a patient receives 20 mg of sodium chloride per hour per kg of body weight. If each drop (drip) is 0.10 mL in volume, calculate the flow rate in drops (drips) per minute necessary for a 60 kg patient.

Therefore, the flow rate in drops (drips) per minute necessary for a 60 kg patient is approximately 32 drops minute.

Explanation:

If 20 mg of sodium chloride is required per hour per kg of body weight, the amount of sodium chloride required per minute per body weight will be calculated as follows:

20 mg/hour/kg * (1 hour/ 60 min) = 1/3 mg/min/kg

For a 60 kg patient, amount of sodium chloride required per minute = 1/3 mg/min/kg * 60 kg = 20 mg/min

Concentration of solution = 6.2 g of sodium chloride per litre

0.10 mL = 0.10 mL * 1 L/1000 mL = 0.0001 L

In 0.10 mL, mass of sodium chloride = 6.2 g/L * 0.0001 L = 0.0062 g = 0.62 mg

If a drop delivers 0.62 mg of sodium chloride, number of drops required to deliver 20 mg of sodium chloride = 20/0.62 = 32.3 drops

Therefore, the flow rate in drops (drips) per minute necessary for a 60 kg patient is approximately 32 drops minute.