7.1 Cardiovascular & Respiratory Conditions
Key Takeaways
- Withhold digoxin and notify the prescriber if the adult apical pulse is below 60 beats per minute, counted for one full minute.
- Warfarin is monitored by INR (therapeutic 2.0-3.0); heparin is monitored by aPTT - never confuse the two on the exam.
- For chronic CO2-retaining COPD clients, titrate oxygen to a target saturation of about 88-92%, not 100%, to protect the hypoxic drive.
- A short-acting beta-2 agonist such as salbutamol is the fastest rescue medication in an acute asthma exacerbation.
- A 2 kg weight gain over two days with dyspnea and ankle edema signals fluid overload from decompensating heart failure.
Cardiovascular and Respiratory Conditions
The Physiological Integrity category is the largest slice of both the CPNRE and REx-PN blueprints (34-58% of scored items), and cardiovascular and respiratory disorders generate a large share of those questions. On the exam you are rarely asked to name a disease; you are asked what to assess first, which finding to report, and what to teach. Anchor every answer in the ABCs (airway, breathing, circulation) and in recognizing early deterioration before it becomes an emergency.
Hypertension and Coronary Artery Disease
Hypertension (HTN) is sustained blood pressure at or above 140/90 mmHg (lower targets apply for diabetes or chronic kidney disease). It is usually asymptomatic - the "silent killer" - so teaching centres on adherence, home blood-pressure monitoring, sodium restriction, weight loss, and activity. High-yield drug classes are ACE inhibitors (ramipril, the "-pril" drugs), ARBs (the "-sartan" drugs), beta-blockers ("-olol"), calcium-channel blockers, and diuretics. A classic item: a client on an ACE inhibitor develops a persistent dry, non-productive cough from bradykinin accumulation - report it, because the prescriber may switch the client to an ARB. Also watch for orthostatic hypotension; teach clients to rise slowly from sitting or lying.
Angina is chest pain from myocardial ischemia. Stable angina is relieved by rest and nitroglycerin. Teach the client to take one sublingual tablet or spray, repeat every 5 minutes up to three doses, and call 911 if pain persists after the first dose. Nitroglycerin causes headache and hypotension, so the client should sit down before taking it.
Acute Coronary Syndrome and Myocardial Infarction
When ischemia becomes infarction (myocardial infarction, MI), the chest pain is unrelieved by rest or nitroglycerin. The classic picture is crushing substernal pressure radiating to the left arm or jaw with diaphoresis, nausea, and dyspnea. Women, older adults, and clients with diabetes may present atypically with only fatigue or indigestion. The memory aid MONA (morphine, oxygen, nitroglycerin, aspirin) lists interventions, but prioritize chewable acetylsalicylic acid (ASA) and activating emergency help. Nursing priorities are the ABCs, a 12-lead ECG, oxygen if the client is hypoxic, continuous cardiac monitoring, and pain relief.
Heart Failure
Heart failure is the heart's inability to pump enough blood to meet demand. Left-sided failure backs up into the lungs, producing dyspnea, orthopnea, crackles, and frothy sputum. Right-sided failure backs up systemically, producing peripheral edema, jugular venous distention, and weight gain. A frequently tested finding: a 2 kg weight gain over two days with worsening dyspnea and ankle edema signals fluid volume overload from decompensating failure. Teach daily morning weights on the same scale, a low-sodium diet, and reporting a gain of more than 1-2 kg. Loop diuretics such as furosemide and monitoring serum potassium are central to care.
Digoxin and Arrhythmia Basics
Digoxin strengthens contraction and slows the heart rate. Before every dose, count the apical pulse for one full minute, and withhold the dose and notify the prescriber if it is below 60 beats per minute in an adult. Early digoxin toxicity presents with anorexia, nausea, and visual disturbances such as yellow-green halos; hypokalemia increases toxicity risk. Atrial fibrillation is an irregularly irregular rhythm that raises stroke risk, so clients are anticoagulated: warfarin is monitored by INR (target 2.0-3.0), whereas heparin is monitored by aPTT. Never mix up these two laboratory tests on the exam.
Respiratory: COPD, Asthma, and Pneumonia
| Condition | Hallmark features | Priority relief |
|---|---|---|
| COPD | Barrel chest, chronic productive cough, prolonged expiration | Low-flow O2 titrated to SpO2 88-92% |
| Asthma | Wheeze, accessory-muscle use, chest tightness | Short-acting beta-2 agonist (salbutamol) |
| Pneumonia | Fever, productive cough, crackles, high WBC | Antibiotics, oxygen, hydration, positioning |
COPD oxygen caution is a common hard item: some clients with chronic carbon-dioxide retention rely on a hypoxic drive, so excessive high-flow oxygen can blunt ventilation. Titrate oxygen to the lowest level that maintains a target saturation, usually 88-92%, not 100%. During an asthma exacerbation the fastest relief is a short-acting beta-2 agonist (salbutamol), which relaxes bronchial smooth muscle; inhaled corticosteroids are for maintenance and act too slowly for rescue. For pneumonia, position the client upright, encourage fluids, deep breathing, coughing, and incentive spirometry to promote lung expansion.
Oxygen Therapy and Safety
Oxygen is a drug: it requires an order and titration. Remember oxygen supports combustion - remove all ignition sources and allow no smoking near an in-use source. Use humidification at higher flows to protect mucous membranes, and monitor for oxygen toxicity with prolonged high concentrations. Match the device to the need: nasal cannula (1-6 L/min), simple mask, and non-rebreather mask for emergencies. Common exam traps include choosing 100% oxygen for a CO2-retaining COPD client, giving the next digoxin dose despite an apical rate of 54, and confusing INR (warfarin) with aPTT (heparin).
Left-Sided vs Right-Sided Heart Failure
| Feature | Left-sided HF | Right-sided HF |
|---|---|---|
| Blood backs up into | Lungs (pulmonary congestion) | Systemic venous circulation |
| Hallmark signs | Dyspnea, orthopnea, crackles, frothy pink sputum | Peripheral edema, jugular venous distention, ascites, hepatomegaly |
| Common trigger | Hypertension, MI, valve disease | Left-sided failure, chronic lung disease |
| Memory aid | Left = Lungs | Right = Rest of the body |
Left-sided failure is the most common cause of right-sided failure. In both, teach daily morning weights on the same scale, fluid and sodium limits, and to report a gain over 1-2 kg or new shortness of breath.
Beta-Blocker and Nitroglycerin Teaching
Beta-blockers (the "-olol" drugs) lower heart rate and blood pressure, so hold and reassess if the apical pulse is below 60 bpm, and warn clients never to stop them abruptly because rebound tachycardia and hypertension can follow. In diabetic clients they can mask the tachycardia of hypoglycemia. Teach clients to store nitroglycerin in its original dark glass bottle away from light and heat, to expect a brief tingling or headache, and to replace tablets about every 6 months.
Clinical Judgment in Action
Two days after an anterior myocardial infarction, a client suddenly reports worsening dyspnea; you hear fine bibasilar crackles, note frothy sputum, an SpO2 of 88%, and a heart rate of 112 bpm. The pattern is acute left-sided heart failure with pulmonary edema, not simple anxiety. Priorities follow the ABCs: sit the client upright in high Fowler's position to ease breathing, apply oxygen, obtain vital signs, and notify the prescriber urgently, anticipating intravenous furosemide. Documentation and reassurance follow the physiological intervention - a sequence the exam consistently rewards.
Before administering digoxin to an adult client, the practical nurse counts an apical heart rate of 54 beats per minute for one full minute. What is the nurse's most appropriate action?
A client with advanced COPD who is known to retain carbon dioxide is started on oxygen. Which oxygen approach is most appropriate?
A client in an acute asthma exacerbation is wheezing and using accessory muscles to breathe. Which medication provides the most rapid relief?