Questions: With a child that weighs 7 kg, which piece of equipment should be used to obtain a blood pressure? A child blood pressure cuff. An infant blood pressure cuff. A newborn blood pressure cuff. A BP cuff that is 1 / 3 the width of the upper arm.

The answer is the second one: An infant blood pressure cuff.

Explanation for each option:

1. A child blood pressure cuff: This option is generally used for older children who weigh more than an infant. A 7 kg child is typically considered an infant, so this cuff might be too large.

2. An infant blood pressure cuff: This is the correct choice. A 7 kg child is typically classified as an infant, and an infant blood pressure cuff is designed to fit the arm size of children in this weight range.

3. A newborn blood pressure cuff: This cuff is designed for newborns, who generally weigh less than 7 kg. Therefore, it would likely be too small for a 7 kg child.

4. A BP cuff that is $1 / 3$ the width of the upper arm: While this option provides a general guideline for selecting the correct cuff size, it is not as specific as the other options. The infant blood pressure cuff is specifically designed for infants, making it the more appropriate choice.

In summary, for a child weighing 7 kg, an infant blood pressure cuff is the most suitable option.