Med-surg: cardiovascular & respiratory: practice questions with explanations

1What this topic covers

Medical-surgical (med-surg) nursing is the care of adults on general hospital wards. Heart and lung problems are the most common reasons these patients deteriorate.

This topic covers heart failure, acute coronary syndromes, hypertension, the basics of arrhythmias, anticoagulants, leg vessel disease, venous thromboembolism, COPD, asthma, pneumonia, chest drains and oxygen devices.

For each condition, learn three things: how it looks at the bedside, what makes it worse, and what the nurse checks or does first. Exam questions test exactly these links.

2Heart failure and acute coronary syndromes

In heart failure the heart cannot pump enough blood for the body’s needs, so fluid backs up behind the failing ventricle:

• Left-sided: blood backs up into the lungs. Breathlessness, crackles, orthopnoea (breathless lying flat) and waking up breathless at night.
• Right-sided: blood backs up into the body’s veins. Ankle or sacral oedema, raised jugular venous pressure, an enlarged liver.

Weigh the patient daily, at the same time and on the same scale. A fast gain of a couple of kilograms over a few days usually means fluid, not fat. Diuretics lower potassium, and low potassium makes digoxin more toxic.

An acute coronary syndrome (ACS) is myocardial ischaemia from a blocked or narrowed coronary artery. Troponin confirms damage to heart muscle. A STEMI usually means a fully blocked artery and needs emergency reperfusion, preferably primary PCI.

Give oxygen only if the saturation is below target. Nitrates are withheld if the systolic pressure is below about 90 mmHg, after a phosphodiesterase-5 inhibitor such as sildenafil, and are used with great care in right ventricular infarction.

3Blood pressure, rhythm and anticoagulation

Hypertension rarely causes symptoms, so it is found by measuring. Very high pressure with new organ damage (confusion, chest pain, kidney injury) is an emergency, but it is lowered gradually: often by no more than about 25% in the first hour.

Atrial fibrillation gives an irregularly irregular pulse and a risk of stroke from clots in the atria. Count the apical and radial pulses together for a full minute to find a pulse deficit. Unstable patients (shock, chest pain, confusion) need urgent synchronised cardioversion.

Anticoagulants prevent clots from forming and growing. Learn how each is monitored and reversed:

• Warfarin: INR, usually 2–3; keep vitamin K intake steady; reversed by vitamin K and prothrombin complex concentrate.
• Unfractionated heparin: aPTT or anti-Xa; reversed by protamine; watch the platelets for heparin-induced thrombocytopenia.
• DOACs such as apixaban: no routine monitoring, dose depends on kidney function; specific reversal agents exist.

4Leg vessels and venous thromboembolism

Arterial and venous disease look different because one is a problem of inflow and the other of outflow:

• Arterial: pain on walking (claudication), cool pale skin, weak pulses, painful punched-out ulcers on the toes. Pain may ease with the legs hanging down.
• Venous: aching, oedema, brown skin, shallow moist ulcers above the inner ankle. Elevation and compression help, but only after an ABPI has excluded significant arterial disease.

A cold, white, pulseless, painful limb is acute limb ischaemia: an emergency. Do not elevate it, compress it or warm it.

A DVT causes one-sided calf swelling, warmth and pain. A pulmonary embolism causes sudden breathlessness, pleuritic pain, tachycardia and low saturation, often with a clear chest. Prevention means mobilising, hydration and prescribed prophylaxis.

5COPD, asthma, pneumonia, chest drains and oxygen

COPD is fixed airflow obstruction, usually from smoking. Many patients are at risk of CO₂ retention, so their oxygen target is often 88–92% with controlled oxygen (Venturi mask or low-flow nasal cannula). Most other acutely ill adults aim for 94–98%.

Asthma is variable, reversible obstruction. A silent chest, exhaustion, confusion, SpO₂ below 92% or a rising PaCO₂ are life-threatening signs. Using a reliever often means poor control.

Pneumonia severity is often scored with CURB-65: Confusion, Urea >7 mmol/L, Respiratory rate ≥30, low Blood pressure and age ≥65.

A chest drain works as a one-way valve. Keep the unit upright and below chest level, look for swinging and bubbling, and do not clamp it routinely. If the tube comes out, cover the hole with an occlusive dressing and get help.

Oxygen devices in increasing strength: nasal cannula (1–4 L/min), simple face mask (5–10 L/min), Venturi mask (fixed percentage), non-rebreather with reservoir (15 L/min), then high-flow nasal oxygen and ventilatory support.

6A worked example

Use the ABCDE approach and link each finding to a cause before you act.

7Common mistakes and how questions look

• Giving high-flow oxygen to a COPD patient with a target of 88–92% and not stepping it down.
• Elevating an ischaemic leg or compressing a leg before arterial disease has been excluded.
• Clamping a chest drain that is still bubbling.
• Forgetting that low potassium makes digoxin toxic and that diuretics lower potassium.
• Treating a high blood pressure as an emergency when there is no organ damage, or lowering it too quickly when there is.

Easy questions test facts: normal ranges, signs of left- and right-sided failure, device flow rates. Medium questions test reasons: why a drug needs a certain test or why a device is used. Hard questions give a deteriorating patient and ask what you do first.