Match the respiratory condition with its hallmark symptom.

Choice A rationale

Administering sedation (e.g., narcotics or benzodiazepines) prior to invasive procedures like suctioning is crucial to blunt the reflex sympathetic response. Suctioning can induce coughing, gagging, and pain, which dramatically increase systemic blood pressure and, consequently, cerebral blood volume and intracranial pressure (ICP), leading to secondary brain injury. Sedation provides analgesia and anxiolysis, minimizing these adverse physiological reactions.

Choice B rationale

Lowering the head of the bed (HOB) can increase cerebral blood flow and impede venous drainage from the head and neck vessels, thereby increasing cerebral blood volume and consequently intracranial pressure (ICP). For a child with severe traumatic brain injury, the HOB should typically be elevated to 30 degrees to promote optimal venous outflow and pressure regulation.

Choice C rationale

While performing suctioning quickly minimizes the duration of the noxious stimulus, it does not address the initial reflexive physiological response to the stimulus itself, which triggers the rise in ICP. The most effective preventative measure is to pre-oxygenate and administer sedation to mitigate the body's adverse reaction before and during the necessary procedure.

Choice D rationale

Delaying suctioning until ICP has already risen is a reactive measure, not a preventative one, and risks secondary brain injury from sustained or high-peak ICP. Suctioning must be performed when secretions compromise airway patency, but the goal is to mitigate the expected ICP rise through proactive interventions like pre-sedation and hyperoxygenation before the procedure is initiated.

Choice A rationale

Hypercyanotic spells, or "tet spells," result from a sudden decrease in pulmonary blood flow and increased right-to-left shunting, leading to profound hypoxemia. Administering oxygen helps by slightly increasing arterial oxygen tension, which acts as a mild pulmonary vasodilator, potentially reducing pulmonary vascular resistance and improving oxygen delivery to tissues. This aims to counteract the immediate hypoxemia.

Choice C rationale

Morphine administration is appropriate because of its central nervous system depressant effects. It helps to calm the infant, decreasing systemic oxygen demands and reducing the hyperpnea (rapid, deep breathing) that often accompanies the spell. Furthermore, morphine mildly vasodilates, which increases systemic vascular resistance, decreasing the right-to-left shunt flow.

Choice E rationale

Placing the infant in the knee-chest position significantly increases systemic vascular resistance (SVR) by compressing the major arteries in the lower extremities. The increased SVR reduces the pressure gradient driving the right-to-left shunt through the ventricular septal defect, thereby increasing pulmonary blood flow and improving oxygen saturation during the hypercyanotic event.