Fundamentals of Nursing

Why D is correct

Negative pressure draws air inward and exhausts it through a dedicated pathway, so its defining purpose is keeping airborne organisms inside the room from escaping out into the hallway.

Why the other options are wrong

• A — entering the room from the corridor: that inward-protection goal describes positive pressure, used for protective isolation, the opposite airflow direction from negative pressure.
• B — escaping into nearby rooms through shared ducts: negative-pressure rooms exhaust through a dedicated pathway rather than shared ductwork into adjoining rooms, so this names the wrong route.
• C — being trapped by the air-filtration system itself: filtration is a secondary feature of the room's ventilation; the defining containment effect comes from the pressure gradient's airflow direction, not filter capture.

Why A is correct

S1 (lub) results from closure of the mitral and tricuspid valves at the start of systole; S2 (dub) results from closure of the aortic and pulmonic valves at the end of systole — valve closure is the direct physical event that generates the sound.

Why the other options are wrong

• B — turbulent blood flow across the ventricular walls during filling: produces S3, a third heart sound, not the normal lub-dub.
• C — contraction of ventricular myocardium during systole: myocardial contraction itself is essentially silent; it is the valve closure it triggers that produces audible sound.
• D — acceleration of blood exiting the aortic and pulmonic outflow tracts: can contribute to murmurs but does not generate the normal S1/S2.

Why A is correct

This client's respiratory status has not been established on this unit, so the nurse needs firsthand data: breath sounds, effort, and oxygenation obtained by her now. Nothing on the chart or in the order tells her what his chest sounds like at this moment.

Assessment opens the nursing process, and the nurse's own findings are what establishes this client's baseline on this unit. A written order, a family's question, and the ED paperwork all describe decisions made before the client arrived. None of them can be acted on safely until that baseline exists.

Why the other options are wrong

• B — "Review the ED transfer note and the medication record on the chart": Chart review is genuine data collection and takes only seconds, but it is another clinician's assessment from another setting and a different hour. It cannot serve as this client's baseline here. A client admitted to rule out pneumonia is assessed with a stethoscope before he is assessed on paper.
• C — "Verify the verbal chest physiotherapy order with the prescriber who gave it": Clarifying a verbal order is proper practice, yet nothing is due to be carried out right now. The nurse cannot judge whether chest physiotherapy suits this client until she has findings to judge it against.
• D — "Explain to the family when antibiotic therapy is likely to begin": An honest answer depends on a plan that does not exist yet. A timing question from the family does not outrank an unassessed respiratory status.

Why A is correct

In hypovolemic shock, elevating the legs (modified Trendelenburg) autotransfuses pooled venous blood back toward the heart and brain, transiently supporting perfusion of the vital organs while volume is replaced.

Why the other options are wrong

• B — head of bed raised 30–45 degrees: this reduces preload and eases breathing, which helps in cardiogenic or distributive shock, but in hypovolemia it further reduces cerebral perfusion — the most dangerous choice here since it echoes the student's suggestion to sit him up.
• C — left lateral position: relieving aortocaval compression is the correct rationale for a pregnant client in supine hypotension, not for hemorrhagic shock in general, so this is the right mechanism applied to the wrong scenario.
• D — full Trendelenburg, head lower than the feet: exaggerating the tilt beyond legs-only elevation does not add further perfusion benefit and instead impairs diaphragmatic excursion and raises aspiration risk — the right general idea taken to the wrong specific technique.

Why D is the answer

Her deep tendon reflexes would be brisk or overactive, not diminished or absent, because hypocalcemia (calcium too low) makes nerves and muscles too easily excited. Diminished reflexes belong to hypercalcemia (calcium too high), the opposite problem from her calcium of 6.4 mg/dL.

Why the other options are not the answer

• A — "Trousseau sign is already present, given the carpal spasm elicited during cuff inflation": This statement is correct. Trousseau sign is the hand and wrist cramping into a spasm when a blood pressure cuff is inflated on the upper arm. Her carpal (wrist) spasm during cuff inflation is a positive Trousseau sign, so it is an expected finding.
• B — "Laryngospasm with potential airway compromise is a possible complication warranting close monitoring": This statement is correct. Severe hypocalcemia can cause laryngospasm (spasm of the voice box muscles). Laryngospasm can block the airway, so close airway monitoring is appropriate, as the statement says.
• C — "Prolonged QT interval and dysrhythmias are cardiac risks that warrant continuous monitoring": This statement is correct. Low calcium can prolong the QT interval (the stretch of the ECG showing the time the heart's lower chambers take to fire and then recover). It can also lead to dysrhythmias (irregular heart rhythms), so cardiac monitoring is appropriate.