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 with a leg injury is climbing stairs with crutches. Which leg should go up first?
AThe unaffected leg
BThe injured leg
CBoth legs together
DThe crutches always go first
2.Nursing fundamentalsHard
A patient has been taught breathing exercises before surgery. Which statement shows a need for further teaching?
A"I'll take some slow deep breaths every hour."
B"I'll hold a pillow over the wound when I cough."
C"I'll avoid coughing so I don't hurt my stitches."
D"I'll ask for pain relief if pain stops me breathing deeply."
3.Clinical nursingMedium
A patient with COPD and known carbon dioxide retention needs a nebulised bronchodilator. How should it usually be given?
AOnly with the patient lying flat
BWithout monitoring oxygen saturation
CDriven by compressed air, with oxygen given separately if needed
DDriven by high-flow oxygen at 15 L/min for as long as possible
4.Clinical nursingHard
Why are liquid medicines for nasogastric tubes drawn up in dedicated enteral (oral) syringes rather than IV syringes?
AEnteral syringes keep the medicine sterile
BTo prevent accidental intravenous administration
CIV syringes cannot hold liquid medicines
DEnteral syringes measure doses less accurately
5.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.38, PaCO₂ 28 mmHg (3.7 kPa) and HCO₃⁻ 16 mmol/L. The primary disorder is metabolic acidosis. How far is it compensated? Click your answer.
pH 7.38PaCO₂ 28 mmHg (3.7 kPa)HCO₃⁻ 16 mmol/L
1uncompensated
2partially compensated
3fully compensated
6.Arterial blood gas interpretationHard
A practice gas shows a respiratory acidosis: pH 7.23, PaCO₂ 64 mmHg (8.5 kPa), HCO₃⁻ 26 mmol/L. Use the rules ‘HCO₃⁻ rises 1 mmol/L per 10 mmHg (acute) or 3.5 mmol/L per 10 mmHg (chronic)’ to classify it. Click your answer.
pH 7.23PaCO₂ 64 mmHg (8.5 kPa)HCO₃⁻ 26 mmol/L
1acute
2chronic
3acute on chronic
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice patient after a head injury opens the eyes when spoken to, talks in sentences but is confused and shows as the best motor response: abnormal flexion of the arms (decorticate posture). Work out the GCS and classify the head injury by it. Click your answer.
1mild
2moderate
3severe
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). An adult weighs 83 kg and is 198 cm tall. Calculate the BMI and click the WHO weight category.
Practice exercise (made-up values, not clinical guidance). A 69 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1 kcal/mL and runs by pump for 20 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 2400 mL of parenteral nutrition with final concentrations of 20% dextrose and 3.5% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
2400 mLdextrose 20%amino acids 3.5%lipid 250 mL · 2 kcal/mL
NPC = kcal/day
11.ECG rhythm strip interpretationMedium
Interpret this lead II rhythm strip. Which rhythm is it? 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
1ventricular bigeminy
2atrial fibrillation
3normal sinus rhythm
4sinus rhythm with PVCs
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
1ventricular tachycardia
2ventricular fibrillation
3atrial fibrillation
4torsades de pointes
13.Prioritization & delegationMedium
A patient on a medical unit tells the nurse he has a plan to end his life and has saved tablets at home. What is the priority action?
AReassure him that things usually look better in the morning after some sleep
BArrange a psychiatry appointment for next week
CAsk him to promise he will not harm himself
DEnsure constant observation and remove anything he could use to harm himself
14.Prioritization & delegationHard
During START triage, an adult is not breathing. The airway is repositioned and the victim still does not breathe. What is the correct category?
ARed, and start CPR at once
BRed, because no breathing is the most urgent finding
CYellow, and come back later
DBlack (deceased or expectant)
15.Infection control & patient safetyMedium
A nurse who never had BCG vaccine has a positive tuberculin skin test for the first time. The chest x-ray is clear and there are no symptoms. What does this most likely mean?
AActive TB, which needs airborne isolation
BA failed test that must be repeated next year
CImmunity to TB from a past exposure
DLatent TB infection, which is not contagious
16.Infection control & patient safetyHard
According to the “Swiss cheese” model of error, why do errors reach patients?
APatients often do not follow their care instructions
BOne careless person makes a mistake that no system could stop
CWeaknesses in several layers of defense line up at the same time
DTechnology fails more often than people do
17.Lab values & electrolytesMedium
A patient with type 2 diabetes has a target HbA1c below 7% (53 mmol/mol). Today's result is 7.8% (62 mmol/mol). What is the best interpretation?
AThe result shows today's fasting glucose is above the target
BGlucose control has been excellent for the past several months
CAverage glucose over the past months has been above the target
DThe patient has had frequent episodes of severe hypoglycemia
18.Lab values & electrolytesHard
A nursing student has a positive interferon-gamma release assay (IGRA) for tuberculosis, no symptoms and a normal chest X-ray. What does this most likely mean?
AActive pulmonary TB, which is contagious
BA false result, as the test does not detect TB
CLatent TB infection, which is not contagious
DPast BCG vaccination only, with no infection
3Solutions
1.Nursing fundamentals
Answer: A · The unaffected leg
Why this is the answer
Going up, the strong leg steps first and lifts the body, followed by the crutches and the injured leg. Going down, the crutches and injured leg go first.
Answer
A · The unaffected leg
2.Nursing fundamentals
Answer: C · "I'll avoid coughing so I don't hurt my stitches."
Why this is the answer
Avoiding coughing lets secretions collect and raises the risk of chest infection. Splinting the wound, deep breathing and good pain control are correct.
Answer
C · "I'll avoid coughing so I don't hurt my stitches."
3.Clinical nursing
Answer: C · Driven by compressed air, with oxygen given separately if needed
Why this is the answer
Nebulisers driven by high-flow oxygen can raise PaCO2 in patients at risk. Air-driven nebulisers are used, with supplementary oxygen via nasal cannulae to keep saturation in the target range.
Answer
C · Driven by compressed air, with oxygen given separately if needed
4.Clinical nursing
Answer: B · To prevent accidental intravenous administration
Why this is the answer
Giving an oral or enteral medicine intravenously can be fatal. Enteral syringes with non-IV connectors, such as ENFit, make this wrong-route error much less likely.
Answer
B · To prevent accidental intravenous administration
5.Arterial blood gas interpretation
Answer: fully compensated
Reading a blood gas (ROME): first the pH: below 7.35 is acidaemia, above 7.45 alkalaemia. Then find the value that explains it. PaCO₂ (normal 35–45 mmHg, 4.7–6.0 kPa) is the respiratory part and moves Opposite to the pH in a respiratory disorder; HCO₃⁻ (normal 22–26 mmol/L) is the metabolic part and moves in the same direction as the pH (Respiratory Opposite, Metabolic Equal). The other value shows the compensation: normal means uncompensated; abnormal in the direction that pulls the pH back while the pH is still abnormal means partially compensated; a normal pH with both values abnormal means fully compensated. Ranges differ slightly between laboratories; these are practice values.
ROME, value by value
pH 7.38: within 7.35–7.45
PaCO₂ 28 mmHg: low (35–45)
HCO₃⁻ 16 mmol/L: low (22–26)
Compensation
Clinically, also check the expected compensation: Winter’s formula expects PaCO₂ 30–34 mmHg, so the measured 28 mmHg points to an additional respiratory alkalosis (a mixed disorder). The answer above is the ROME exam classification.
fully compensated
Answer
fully compensated
6.Arterial blood gas interpretation
Answer: acute
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 HCO₃⁻
acute: 24 + 1·2.4 = 26.4 mmol/L
chronic: 24 + 3.5·2.4 = 32.4 mmol/L
Compare
measured: 26 mmol/L → acute
Answer
acute
7.Clinical assessment scores
Answer: moderate
Glasgow Coma Scale: add the best response in three areas. Eye opening E: 4 spontaneous, 3 to sound or speech, 2 to pressure, 1 none. Verbal V: 5 oriented, 4 confused, 3 inappropriate words, 2 incomprehensible sounds, 1 none. Motor M: 6 obeys commands, 5 localises, 4 normal flexion (withdraws), 3 abnormal flexion, 2 extension, 1 none. The total runs from 3 to 15. After a head injury, 13–15 is usually called mild, 9–12 moderate and 3–8 severe.
Score each area
E: opens the eyes when spoken to → 3
V: talks in sentences but is confused → 4
M: abnormal flexion of the arms (decorticate posture) → 3
Add
GCS = 3 + 4 + 3 = 10
Severity
GCS 10 → moderate
Answer
moderate
8.Clinical assessment scores
Answer: healthy weight
Body mass index: BMI = weight (kg)/height (m)², with the height converted to metres first. With pounds and inches, BMI = 703 × weight (lb)/height (in)². WHO adult categories: below 18.5 underweight, 18.5–24.9 healthy weight, 25.0–29.9 overweight, 30.0–34.9 obesity class I, 35.0–39.9 obesity class II and 40 or more obesity class III.
BMI
BMI = 83/1.98² = 21.17
Category
healthy weight
Answer
healthy weight
9.Enteral & parenteral nutrition calculations
Answer: R = 104 mL/h
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.
Energy needed
E = 30·69 = 2070 kcal/day
Daily volume
V = 2070/1 = 2070 mL/day
Pump rate
R = 2070/20 = 103.5 ≈ 104 mL/h
Answer
R = 104 mL/h
10.Enteral & parenteral nutrition calculations
Answer: NPC = 2132 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: 20·2400/100 = 480 g
amino acids: 3.5·2400/100 = 84 g
Kilocalories per component
dextrose: 480·3.4 = 1632 kcal
amino acids: 84·4 = 336 kcal
lipid: 250·2 = 500 kcal
Non-protein energy
NPC = 1632 + 500 = 2132 kcal/day
Answer
NPC = 2132 kcal/day
11.ECG rhythm strip interpretation
Answer: ventricular bigeminy
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.
Five steps
1. Rate: 8 QRS complexes in 6 s, × 10 = 80 per minute.
2. Rhythm: regularly irregular, a short and a long R–R alternate (0.40 s and 1.04 s).
3. P waves: upright before every narrow QRS; none before the early wide beats.
4. PR interval: 0.14 s, constant, within 0.12–0.20 s.
5. QRS: 0.08 s in the sinus beats; the early beats are wide (0.14 s) and bizarre, with the T wave pointing the other way.
Interpretation
ventricular bigeminy
Answer
ventricular bigeminy
12.ECG rhythm strip interpretation
Answer: ventricular tachycardia
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: R–R = 10 small boxes, 1500 ÷ 10 ≈ 150 per minute.
2. Rhythm: regular, every R–R is 0.40 s.
3. P waves: none identifiable.
4. PR interval: not measurable.
5. QRS: 0.16 s, wide (0.12 s or more).
Interpretation
ventricular tachycardia
Answer
ventricular tachycardia
In resuscitation guidelines VF and pulseless VT are the shockable rhythms. This is identification practice only.
13.Prioritization & delegation
Answer: D · Ensure constant observation and remove anything he could use to harm himself
Why this is the answer
A patient with a plan and means is at high risk. Safety comes first: constant observation, removal of means and urgent referral. A “no-harm promise” does not protect the patient.
Answer
D · Ensure constant observation and remove anything he could use to harm himself
14.Prioritization & delegation
Answer: D · Black (deceased or expectant)
Why this is the answer
In START, a victim who does not breathe after the airway is repositioned is tagged black. CPR for one person would take rescuers away from many others who could survive. If breathing starts after repositioning, the victim is red.
Answer
D · Black (deceased or expectant)
15.Infection control & patient safety
Answer: D · Latent TB infection, which is not contagious
Why this is the answer
A positive skin test with no symptoms and a normal chest x-ray suggests latent TB infection. The person cannot spread TB but should be evaluated for treatment to prevent active disease later.
Answer
D · Latent TB infection, which is not contagious
16.Infection control & patient safety
Answer: C · Weaknesses in several layers of defense line up at the same time
Why this is the answer
Reason’s Swiss cheese model shows that each safety layer, such as prescribing, dispensing, checking and scanning, has weaknesses. Harm happens when the holes in several layers line up, so safety improvement focuses on strengthening the system.
Answer
C · Weaknesses in several layers of defense line up at the same time
17.Lab values & electrolytes
Answer: C · Average glucose over the past months has been above the target
Why this is the answer
An HbA1c of 7.8% shows that average glucose has been above the individual target over about 2–3 months. The nurse explores diet, activity, medication use and barriers, and the treatment plan may be adjusted.Checked against:Hemoglobin A1C (HbA1c) Test · MedlinePlus (NIH) (2025)
Answer
C · Average glucose over the past months has been above the target
18.Lab values & electrolytes
Answer: C · Latent TB infection, which is not contagious
Why this is the answer
A positive IGRA with no symptoms and a normal chest X-ray indicates latent TB infection, which cannot spread to others. Treatment of latent TB is often offered to prevent later active disease. The IGRA is much less likely than the skin test to give a false-positive result after BCG vaccination.Checked against:Tuberculosis Screening · MedlinePlus (NIH) (2026); PPD skin test · MedlinePlus (NIH) (2025)