Which characteristics of capillaries cause restriction of blood flow?

high blood pressure

small diameters

thin walls

short lengths

B. Small diameters is the characteristic of capillaries that causes restriction of blood flow.
Since it is a narrow passage, not a lot of blood can pass through it at the same time. 

Which characteristics of capillaries cause restriction of blood flow?

- small diameters

The answer would be true.

20 times a minute is usually the average respritory rate of an adult. additionally the patient is breathing on his own, is clearly maintaining his airway, and is intaking a sufficient amount of air. you shouldn't use a bag valve mask, cpap, or other form of positive pressure ventilation, unless the patient has lost control of his airway, and is not breathing (apneic) or has rapid breathing or slow and shallow respirations. this patient would most likely and should be put on an non-rebreather mask or nrb attached to 100% high flow oxygen at 15 l/min. don't use a nasal cannula, as the amount of oxygen it provides is limited with a rate of 6 l/min.