The practical nurse (PN) reviews instructions for use of polyethylene glycol with a client scheduled for a colonoscopy. Which instruction should the PN include?

Choice A reason: Pupils equal and reactive to light assess neurological status, not bronchodilator effectiveness. Bronchodilators, like albuterol, relax airway smooth muscles, improving breathing in emphysema. Pupil response is unrelated to respiratory function, making this choice irrelevant for evaluating the drug’s impact.

Choice B reason: Heart rate of 106 beats/minute may reflect a bronchodilator side effect, as beta-agonists stimulate cardiac beta receptors, causing tachycardia. However, it does not measure effectiveness, which is assessed by improved airway function, like respiratory rate, making this choice incorrect.

Choice C reason: Respiratory rate of 22 breaths/minute indicates bronchodilator effectiveness, as these drugs dilate airways, reducing work of breathing in emphysema. A normalized rate suggests improved airflow and oxygenation, directly reflecting the drug’s therapeutic action on bronchial smooth muscle relaxation.

Choice D reason: Urine output of 40 mL/hour monitors renal function, not bronchodilator efficacy. Bronchodilators target airway dilation, not fluid balance. This finding is unrelated to emphysema treatment or the drug’s respiratory effects, making it irrelevant for assessing medication effectiveness.

Choice A reason: Ankle circumference monitors edema, which mannitol reduces by drawing fluid from tissues. However, this is secondary to urinary output, as mannitol’s primary action is diuresis, increasing urine production to reduce intracranial or intraocular pressure, making edema measurement less critical.

Choice B reason: Heart rate is relevant for overall monitoring but not the primary outcome for mannitol, which acts as an osmotic diuretic. Cardiovascular effects are secondary, and mannitol’s efficacy is better assessed by urine output, which directly reflects its diuretic mechanism.

Choice C reason: Dietary intake is unrelated to mannitol’s therapeutic effect. Mannitol pulls fluid into the bloodstream, increasing urine output, not influenced by diet. Monitoring intake may be relevant for other conditions, but it is not critical for assessing mannitol’s diuretic action.

Choice D reason: Urinary output is the most important outcome, as mannitol, an osmotic diuretic, increases urine production by drawing fluid into the renal tubules, reducing intracranial or intraocular pressure. Adequate output (e.g., >30 mL/hour) confirms efficacy, preventing fluid overload or renal complications.