A patient being supported with endotracheal intubation and mechanical ventilation is increasingly agitated. What is the most appropriate nursing intervention?

Rationale:

A. Beans are a safe source of protein, fiber, and other nutrients and do not interfere with the absorption, metabolism, or excretion of theophylline. Including beans in the diet will not affect the drug’s therapeutic levels or increase the risk of toxicity. Therefore, there is no need to omit beans from the client’s meal tray.

B. Milk and other dairy products are also safe for clients taking theophylline. Calcium in milk does not impact the pharmacokinetics of theophylline or reduce its effectiveness. The client can safely consume milk as part of their regular diet without concern for interactions with the medication.

C. Peas are another safe and nutritious food that has no known interaction with theophylline. They provide vitamins, minerals, and fiber but do not affect drug levels or the risk of side effects. Including peas on the meal tray is appropriate and does not pose a safety concern.

D. Coffee contains caffeine, which belongs to the same pharmacologic class as theophylline, called methylxanthines. Consuming caffeine while taking theophylline can lead to additive stimulant effects, increasing central nervous system stimulation and causing restlessness, insomnia, or anxiety. It can also increase cardiac stimulation, leading to tachycardia, palpitations, and potentially dangerous arrhythmias. Additionally, caffeine may exacerbate gastrointestinal side effects such as nausea, vomiting, or abdominal discomfort. Because caffeine can potentiate theophylline toxicity even when the medication is at therapeutic levels, it is essential to avoid coffee and other caffeinated products, including tea, chocolate, energy drinks, and some sodas. The nurse should educate the client about reading labels and monitoring their total caffeine intake to ensure safe theophylline therapy.

Rationale:

A. Nasogastric suctioning removes gastric contents, including hydrochloric acid. This loss of acid can lead to metabolic alkalosis, not respiratory acidosis, because it affects the bicarbonate-to-acid balance in the blood. It does not interfere with CO2 retention or the respiratory process, so it does not directly cause respiratory acidosis.

B. Sedatives, including benzodiazepines, barbiturates, or opioids, can depress the central respiratory center in the brainstem. When the respiratory drive is suppressed, the patient breathes more slowly or shallowly, resulting in hypoventilation. Hypoventilation leads to CO2 retention, which combines with water to form carbonic acid, lowering blood pH and causing respiratory acidosis. This is a common scenario in overdose situations, particularly in older adults or patients with pre-existing lung disease.

C. CNS depression can result from head trauma, stroke, tumors, or other neurologic disorders that impair the brain’s ability to regulate breathing. Like sedative overdose, CNS depression reduces respiratory drive, leading to inadequate alveolar ventilation, CO2 accumulation, and respiratory acidosis. This is why monitoring respiratory rate, depth, and ABGs is critical in patients with CNS compromise.

D. Diabetic ketoacidosis (DKA) causes metabolic acidosis due to the accumulation of ketone bodies, not respiratory acidosis. Patients with DKA usually hyperventilate (Kussmaul respirations) as a compensatory mechanism to blow off CO2 and partially correct the acidosis. Therefore, DKA predisposes to metabolic, not respiratory, acid-base disturbances.

E. Anxiety and fear typically lead to hyperventilation, in which the patient breathes rapidly and deeply. This causes excessive CO2 elimination, lowering PaCO2 and resulting in respiratory alkalosis, the opposite of respiratory acidosis.