Read the pH: below 7.35 is acidosis, above 7.45 alkalosis.
Find the value that explains it: PaCO₂ moving opposite to the pH is respiratory, HCO₃⁻ moving with the pH is metabolic.
Look at the other value: normal means uncompensated, abnormal in the compensating direction means partial compensation, and a normal pH with both abnormal means full compensation.
In a metabolic acidosis, compare PaCO₂ with Winter’s formula, 1.5·HCO₃⁻ + 8 ± 2, and calculate the anion gap Na⁺ − (Cl⁻ + HCO₃⁻).
Check a high anion gap with the delta ratio and, when albumin is low, with the corrected gap.
Write down what is asked: a pump rate, a volume, kilocalories, grams of protein or water.
Turn energy into volume with mL = kcal/(kcal/mL), and volume into protein with litres × g/L.
Divide by the hours the feed actually runs for a rate, or by the number of feeds for a bolus.
For needs, multiply kcal/kg or g/kg by the weight the rule names; find the ideal body weight with Devine: 50 or 45.5 + 2.3 × (inches − 60).
For PN, find grams as % × mL/100, then use 3.4 kcal/g for dextrose, 4 kcal/g for amino acids and the stated kcal/mL for lipid.
ECG rhythm strip interpretation
Paper (25 mm/s, 10 mm/mV)
1 small box = 0.04 s, 1 large box = 0.20 s, 10 mm = 1 mV
Heart rate, regular rhythm
300 ÷ large boxes = 1500 ÷ small boxes = 60 ÷ RR (s)
Heart rate, irregular rhythm
QRS complexes in 6 s × 10
Normal PR interval
0.12–0.20 s
Normal QRS duration
< 0.12 s
QTc (Bazett)
QT/√RR
QTc (Fridericia)
QT/∛RR
QTc (Framingham)
QT + 154·(1 − RR)
Sinus rates
bradycardia < 60, normal 60–100, tachycardia > 100 /min
Escape rates
junctional 40–60, ventricular 20–40 /min
Fast rhythms
SVT 150–250 /min (narrow), VT > 100 /min (wide)
Method
Rate: for a regular rhythm divide 300 by the large boxes or 1500 by the small boxes between two R waves; for an irregular rhythm count the QRS complexes in 6 seconds and multiply by 10.
Rhythm: compare the R–R intervals. Equal is regular; a repeating pattern is regularly irregular; no pattern at all is irregularly irregular.
P waves: is there an upright P wave in lead II before every QRS, all alike? Look for fibrillatory or sawtooth waves, inverted P waves and P waves without a QRS.
PR interval: from the start of P to the start of the QRS, normally 0.12–0.20 s and constant. Watch whether it lengthens, stays fixed before a dropped beat, or varies at random.
QRS duration: below 0.12 s is narrow; 0.12 s or more is wide. Then name the rhythm, and for the QT use QTc = QT/√RR (Bazett) with times in seconds.
Prioritization & delegation
Method
Ask what will harm the patient soonest if nothing is done.
Apply ABC (C-A-B in cardiac arrest), then Maslow: physiological needs before safety, safety before psychological needs.
Compare the options: acute before chronic, unstable before stable, unexpected before expected, systemic before local, and check each finding against the patient’s baseline.
Assess before you act unless it is an emergency; then choose the step the others depend on.
For delegation, check the five rights: task, circumstance, person, directions and supervision. Assessment, teaching and evaluation stay with the RN.
Infection control & patient safety
Method
Start with standard precautions for every patient: hand hygiene, PPE for the expected exposure, safe sharps.
Keep sterile items sterile: if in doubt, it is not sterile; replace, never wipe.
Prevent harm in the environment: fall measures, restraints only as a last resort, RACE and PASS for fire.
Check the rights of medication administration, two identifiers and extra safeguards for high-alert drugs; report errors and near misses.
Lab values & electrolytes
Method
Compare the value with the laboratory’s own reference range, then with the patient’s baseline and trend.
Check the sample: hemolysis, a delay, or blood drawn near an IV can give false results.
Link the value to its typical signs and to the drugs and conditions that cause it.
Look for interactions: low potassium or magnesium increases digoxin toxicity; dehydration raises lithium.
Act on the patient: assess, hold a drug if the level is unsafe, read back critical values and inform the prescriber.
2Practice problems
1.Nursing fundamentalsMedium
A patient refuses their regular evening tablets. What should the nurse do first?
AInsist until the patient takes them
BExplore the reason for refusing
CHide the tablets in their food
DThrow the tablets away without telling anyone
2.Nursing fundamentalsHard
A patient has acute diarrhoea and is suspected of having Clostridioides difficile. Which combination of measures is correct?
AWear a respirator mask only and no gloves
BWait for the lab result before taking any precautions
CUse alcohol hand rub only, and keep the patient in a shared bay with the curtains drawn
DIsolate the patient, use gloves and apron, and wash hands with soap and water
3.Clinical nursingMedium
A patient with pneumonia is breathless and coughing up thick sputum. Which nursing measure helps most with breathing?
ASitting the patient upright and supporting them to clear secretions
BDiscouraging coughing to save energy
CLying the patient flat so that they can rest and conserve energy
DRestricting all oral fluids
4.Clinical nursingHard
A patient with a COPD exacerbation remains acidotic with a high PaCO2 despite optimal medical treatment and controlled oxygen. Which treatment is usually considered next?
ANon-invasive ventilation
B15 L/min oxygen via a non-rebreathe mask
CSedation to slow the breathing
DStopping all oxygen therapy
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 131 mmol/L, glucose 5.1 mmol/L and urea 4.6 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 131 mmol/Lglucose 5.1 mmol/Lurea 4.6 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
A practice gas shows a metabolic alkalosis with HCO₃⁻ 41 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 41 mmol/L
PaCO₂ = mmHg
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 12/min, SpO₂ 91% on room air, blood pressure 78/46 mmHg, pulse 114/min, alert, temperature 35.0 °C. What is the NEWS2 total score?
RR 12SpO₂ 91%airSBP 78HR 114AT 35.0 °C
NEWS2 =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). A practice patient is assessed with the Morse fall scale: history of falling in the last 3 months: no; secondary diagnosis: no; ambulatory aid: none, bed rest or nurse assists; IV therapy or saline lock: no; gait: weak; mental status: knows own limits. Using the cut-offs 0–24 low, 25–44 moderate and 45 or more high, click the fall-risk level.
Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a woman who is 154 cm tall (1 in = 2.54 cm). Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 2000 mL of parenteral nutrition with final concentrations of 25% dextrose and 4% amino acids, plus 500 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
2000 mLdextrose 25%amino acids 4%lipid 500 mL · 2 kcal/mL
NPC = kcal/day
11.ECG rhythm strip interpretationMedium
This lead II strip shows atrial flutter with a fixed conduction ratio. Find the ventricular rate in beats per minute.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
ventricular rate = bpm
12.ECG rhythm strip interpretationHard
Identify the rhythm on this lead II strip. Click your answer.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
1asystole
2atrial fibrillation
3atrial flutter, 4:1 conduction
4ventricular fibrillation
13.Prioritization & delegationMedium
A young adult has just started an SSRI antidepressant for major depression. What should the nurse monitor most closely in the first weeks?
ARising blood glucose levels
BHair growth and skin color
CWeight loss from too much appetite
DThoughts of suicide or self-harm
14.Prioritization & delegationHard
Four patients arrive at the emergency department at the same time. Who should be seen first?
AAn adult with kidney stone pain of 9/10 and stable vital signs
BA child with a temperature of 39 °C who is alert and drinking
CA young adult with a swollen, painful ankle after a fall on the stairs
DAn older adult with weakness on one side that began 40 minutes ago
15.Infection control & patient safetyMedium
Which IV fluid can be given with packed red blood cells in the same line?
A0.9% sodium chloride
B5% dextrose in 0.45% sodium chloride
C5% dextrose in water
DLactated Ringer’s (Hartmann’s) solution
16.Infection control & patient safetyHard
A patient is prescribed hydralazine, but the pharmacy has sent hydroxyzine. What should the nurse do?
AGive it now and tell the prescriber afterwards
BGive it, because the two drug names are almost the same
CGive half the dose of hydroxyzine as a compromise
DNot give it, and contact the pharmacy to obtain the correct drug
17.Lab values & electrolytesMedium
A patient with diabetes also takes propranolol. Why is regular glucose monitoring especially important?
AThe drug can mask warning signs of hypoglycemia
BThe drug stops the meter from reading correctly
CThe drug blocks the insulin injection site
DThe drug causes very high glucose in all patients
18.Lab values & electrolytesHard
A patient on high-dose dexamethasone has a white cell count of 15 × 10³/µL, mostly mature neutrophils with no bands. They have no fever and no signs of infection. What is the most likely explanation?
AA new leukemia that is confirmed by this result alone
BA steroid effect that moves neutrophils into the circulating blood
CA laboratory error, because steroids always lower the white count
DCertain sepsis that needs antibiotics started without delay
3Solutions
1.Nursing fundamentals
Answer: B · Explore the reason for refusing
Why this is the answer
Patients with capacity may refuse medicines. The nurse explores why, for example side effects or misunderstanding, gives information, documents the refusal and informs the prescriber if needed.
Answer
B · Explore the reason for refusing
2.Nursing fundamentals
Answer: D · Isolate the patient, use gloves and apron, and wash hands with soap and water
Why this is the answer
Suspected C. difficile needs prompt isolation with contact precautions. Spores are not killed by alcohol, so hands are washed with soap and water, and the environment is cleaned with a sporicidal agent such as chlorine.
Answer
D · Isolate the patient, use gloves and apron, and wash hands with soap and water
3.Clinical nursing
Answer: A · Sitting the patient upright and supporting them to clear secretions
Why this is the answer
An upright position improves lung expansion, and adequate fluids, deep breathing and coughing help clear sputum. Oxygen is given to target saturations if needed.
Answer
A · Sitting the patient upright and supporting them to clear secretions
4.Clinical nursing
Answer: A · Non-invasive ventilation
Why this is the answer
In hypercapnic respiratory failure from COPD that persists despite treatment, non-invasive ventilation (bilevel positive pressure) supports ventilation and lowers PaCO2. Stopping oxygen would cause dangerous hypoxia.
Answer
A · Non-invasive ventilation
5.Arterial blood gas interpretation
Answer: Osm = 272 mOsm/kg
Derived values: calculated serum osmolality is 2·Na⁺ + glucose + urea with all values in mmol/L (2·Na⁺ + glucose/18 + BUN/2.8 with glucose and BUN in mg/dL); normal is about 275–295 mOsm/kg. The P/F ratio is PaO₂ divided by FiO₂ as a fraction. The alveolar oxygen pressure is PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 mmHg at sea level, and the A–a gradient is PAO₂ − PaO₂.
Calculated osmolality
Osm = 2·131 + 5.1 + 4.6 = 271.7 ≈ 272 mOsm/kg
Answer
Osm = 272 mOsm/kg
6.Arterial blood gas interpretation
Answer: PaCO₂ = 49.7 mmHg
Expected compensation: in metabolic acidosis Winter’s formula predicts PaCO₂ = 1.5·HCO₃⁻ + 8 ± 2 mmHg; a measured value above that range points to an additional respiratory acidosis, below it to an additional respiratory alkalosis. The anion gap AG = Na⁺ − (Cl⁻ + HCO₃⁻), normally about 8–12 mmol/L, separates high-gap from normal-gap metabolic acidosis; low albumin hides a high gap (add 2.5 per g/dL that albumin is below 4.0). The delta ratio (AG − 12)/(24 − HCO₃⁻) between about 0.8 and 2 fits a pure high-gap acidosis (some texts use 1 instead of 0.8), below that an added normal-gap acidosis, and above 2 an added metabolic alkalosis.
Expected PaCO₂
0.7·41 + 21 = 49.7 mmHg
Answer
PaCO₂ = 49.7 mmHg
The rise has a limit: PaCO₂ rarely goes above about 55 mmHg from compensation alone.
7.Clinical assessment scores
Answer: NEWS2 = 11
NEWS2 (National Early Warning Score 2, Royal College of Physicians 2017): score each of the seven parameters with the chart (respiration rate, SpO₂ on scale 1, air or supplemental oxygen, systolic blood pressure, pulse, consciousness on the ACVPU scale and temperature) and add the scores. Clinical risk: 0–4 low; a score of 3 in any single parameter low–medium; 5–6 medium; 7 or more high. A total of 5 or more needs an urgent response.
Score each parameter
RR 12/min → 0
SpO₂ 91% → 3
on air → 0
SBP 78 mmHg → 3
HR 114/min → 2
alert (A) → 0
T 35.0 °C → 3
Add
NEWS2 = 0 + 3 + 0 + 3 + 2 + 0 + 3 = 11
Answer
NEWS2 = 11
8.Clinical assessment scores
Answer: low risk
Morse fall scale: six items. History of falling: no 0, yes 25. Secondary diagnosis: no 0, yes 15. Ambulatory aid: none, bed rest or nurse assistance 0; crutches, cane or walker 15; holding on to furniture 30. IV therapy or saline lock: no 0, yes 20. Gait: normal, bed rest or wheelchair 0; weak 10; impaired 20. Mental status: knows own limits 0; overestimates or forgets limits 15. The total runs from 0 to 125. Risk cut-offs differ between hospitals; a common set is 0–24 low, 25–44 moderate and 45 or more high.
Score each item
history of falling in the last 3 months: no → 0
secondary diagnosis: no → 0
ambulatory aid: none, bed rest or nurse assists → 0
IV therapy or saline lock: no → 0
gait: weak → 10
mental status: knows own limits → 0
Add
Morse total = 0 + 0 + 0 + 0 + 10 + 0 = 10
Risk level
10 → low risk
Answer
low risk
9.Enteral & parenteral nutrition calculations
Answer: IBW = 46.9 kg
Needs and free water: energy needs are often estimated as kcal/kg/day × weight and protein needs as g/kg/day × weight. A formula is only partly water, so its free water = volume × water fraction; water flushes make up the rest of the daily fluid goal. Ideal body weight (Devine): IBW = 50 kg + 2.3 kg for every inch over 5 feet (60 in) for men, and 45.5 kg + 2.3 kg per inch over 60 in for women; 1 in = 2.54 cm. The formula is meant for adults at least 152.4 cm (5 ft) tall. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Height in inches
154 cm/2.54 = 60.63 in
Ideal body weight (Devine)
IBW = 45.5 + 2.3·(60.63 − 60) = 46.95 ≈ 46.9 kg
Answer
IBW = 46.9 kg
10.Enteral & parenteral nutrition calculations
Answer: NPC = 2700 kcal/day
Parenteral nutrition: dextrose provides 3.4 kcal/g, amino acids 4 kcal/g and lipid emulsion the kcal/mL stated (2 kcal/mL for 20%, 1.1 kcal/mL for 10%). Grams = % × mL/100. Non-protein kcal (NPC) = dextrose + lipid kcal; nitrogen = protein/6.25. The glucose infusion rate (GIR) in mg/kg/min = dextrose mg/(kg × minutes). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Grams of dextrose and amino acids
dextrose: 25·2000/100 = 500 g
amino acids: 4·2000/100 = 80 g
Kilocalories per component
dextrose: 500·3.4 = 1700 kcal
amino acids: 80·4 = 320 kcal
lipid: 500·2 = 1000 kcal
Non-protein energy
NPC = 1700 + 1000 = 2700 kcal/day
Answer
NPC = 2700 kcal/day
11.ECG rhythm strip interpretation
Answer: ventricular rate = 75 bpm
Rhythm criteria (lead II): sinus rhythm has an upright P wave before every QRS, a constant PR of 0.12–0.20 s and a narrow QRS: normal sinus rhythm at 60–100/min, sinus bradycardia below 60, sinus tachycardia above 100. Atrial fibrillation: no P waves, a fibrillatory baseline and an irregularly irregular R–R. Atrial flutter: sawtooth flutter waves at about 250–350/min with a fixed conduction ratio such as 2:1 or 4:1. First-degree AV block: sinus rhythm with a constant PR above 0.20 s. Junctional rhythm: narrow QRS at 40–60/min with absent or inverted P waves (PR below 0.12 s, or P after the QRS). A PVC is an early, wide (0.12 s or more), bizarre QRS without a P wave, with the T wave in the opposite direction and usually a full compensatory pause; in bigeminy every second beat is a PVC.
Flutter waves
F–F = 5 small boxes = 0.20 s → 1500 ÷ 5 = 300 per minute
QRS complexes
R–R = 20 small boxes = 0.80 s → 1500 ÷ 20 = 75 per minute
conduction ratio = 300 ÷ 75 = 4:1
Answer
ventricular rate = 75 bpm
12.ECG rhythm strip interpretation
Answer: ventricular fibrillation
Ventricular rhythms: ventricular tachycardia is a run of three or more wide (0.12 s or more) complexes in a row at more than 100/min, usually 150–250/min, regular, without related P waves. Ventricular fibrillation is a chaotic, irregular waveform with no identifiable P waves, QRS complexes or T waves and no countable rate. Asystole is an almost flat line with no ventricular activity; a flat line is always confirmed by checking the patient, the leads and the gain and a second lead. In resuscitation guidelines VF and pulseless VT are the shockable rhythms and asystole is not.
Five steps
1. Rate: no countable ventricular rate.
2. Rhythm: chaotic, no repeating pattern.
3. P waves: none identifiable.
4. PR interval: not measurable.
5. QRS: no QRS complexes.
Interpretation
ventricular fibrillation
Answer
ventricular fibrillation
In resuscitation guidelines VF and pulseless VT are the shockable rhythms. This is identification practice only.
13.Prioritization & delegation
Answer: D · Thoughts of suicide or self-harm
Why this is the answer
In the early weeks of antidepressant treatment, especially in young people, suicidal thoughts may increase. Patients and families are taught to report them at once.
Answer
D · Thoughts of suicide or self-harm
14.Prioritization & delegation
Answer: D · An older adult with weakness on one side that began 40 minutes ago
Why this is the answer
Sudden one-sided weakness suggests a stroke, and treatment depends on how quickly it starts. Severe kidney stone pain needs prompt pain relief, but the patient is stable.
Answer
D · An older adult with weakness on one side that began 40 minutes ago
15.Infection control & patient safety
Answer: A · 0.9% sodium chloride
Why this is the answer
Only 0.9% sodium chloride is compatible with blood. Dextrose (glucose) solutions can cause red cells to clump and break down, and the calcium in lactated Ringer’s (Hartmann’s) can cause clotting.
Answer
A · 0.9% sodium chloride
16.Infection control & patient safety
Answer: D · Not give it, and contact the pharmacy to obtain the correct drug
Why this is the answer
Hydralazine is an antihypertensive, while hydroxyzine is an antihistamine used for itching and anxiety. Giving the wrong drug is a medication error. The nurse withholds it, gets the correct drug and reports the dispensing error.
Answer
D · Not give it, and contact the pharmacy to obtain the correct drug
17.Lab values & electrolytes
Answer: A · The drug can mask warning signs of hypoglycemia
Why this is the answer
Beta-blockers, especially nonselective ones, blunt adrenergic warning signs of hypoglycemia such as tremor and tachycardia, and they can delay recovery. Sweating usually remains. Glucose checks help detect lows that the patient may not feel.Checked against:Low blood sugar · MedlinePlus (NIH) (2026)
Answer
A · The drug can mask warning signs of hypoglycemia
18.Lab values & electrolytes
Answer: B · A steroid effect that moves neutrophils into the circulating blood
Why this is the answer
Corticosteroids raise the neutrophil count by releasing marginated neutrophils and slowing their exit from the blood, usually without a left shift. The nurse still assesses carefully, because steroids can also hide the usual signs of infection.
Answer
B · A steroid effect that moves neutrophils into the circulating blood