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
How can nurses help patients sleep better on a hospital ward at night?
AGroup care and observations so patients are disturbed less often
BGive every patient a sleeping tablet
CKeep the main lights on so staff can see clearly
DDo routine tasks such as bed changes at midnight while it is quiet
2.Nursing fundamentalsHard
Which group of signs suggests a patient may be in the last days of life?
AChanges in breathing pattern, cool mottled skin and reduced intake
BRising appetite and increasing alertness
CBetter mobility and more energy
DA rising urine output and warm hands
3.Clinical nursingMedium
A patient started on an ACE inhibitor develops a persistent dry cough. What is the likely cause?
APulmonary embolism
BAsthma caused by a beta-blocker
CA recognised side effect of the ACE inhibitor
DAn allergic reaction to a recently given penicillin
4.Clinical nursingHard
A nurse teaches a patient with heart failure about self-care. Which statement shows a need for further teaching?
A"I will report it if I need more pillows to sleep."
B"I will take my water tablet in the morning."
C"I will weigh myself each morning after passing urine."
D"I only need to weigh myself once a month."
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 63 mmHg (8.4 kPa). Use the rule that in acute respiratory acidosis HCO₃⁻ rises by 1 mmol/L for every 10 mmHg that PaCO₂ is above 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.
A practice gas shows a metabolic alkalosis with HCO₃⁻ 42 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 42 mmol/L
PaCO₂ = mmHg
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, says inappropriate, random words and shows as the best motor response: moves a hand to the site of pressure (localises). 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). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 14/min, SpO₂ 98% on room air, blood pressure 84/50 mmHg, pulse 76/min, alert, temperature 38.1 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). An 88 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1.5 kcal/mL and runs by pump for 24 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). A child who weighs 12.5 kg receives 5% dextrose at 50 mL/h. Find the glucose infusion rate GIR in mg/kg/min. Round to two decimal places.
12.5 kg5%50 mL/h
GIR = mg/kg/min
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
1atrial flutter, 2:1 conduction
2sinus tachycardia
3normal sinus rhythm
4supraventricular tachycardia (SVT)
12.ECG rhythm strip interpretationHard
This lead II strip shows a conduction problem between the atria and the ventricles. 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
1second-degree AV block type I (Wenckebach)
2third-degree (complete) AV block
3junctional rhythm
4first-degree AV block
13.Prioritization & delegationMedium
A patient reports pain of 8/10. Before giving the prescribed as-needed analgesic, what does the nurse do first?
AAssess the location, character and onset of the pain and the vital signs
BTell the patient to wait until the next scheduled dose is due in two hours
CAsk the nursing assistant to reposition the patient
DGive the strongest analgesic on the chart straight away
14.Prioritization & delegationHard
A patient with known abdominal aortic aneurysm suddenly has severe back pain, a pulsing mass in the abdomen and a falling blood pressure. What should the nurse do?
ACall for emergency help at once and prepare for urgent surgery
BEncourage the patient to walk to ease the back pain
CPalpate the mass firmly to check its size and spread
DGive an oral analgesic and reassess the patient in about one hour
15.Infection control & patient safetyMedium
What should a nurse do after an accidental splash of a patient’s blood into the eyes?
ARinse the eyes at once with plenty of water or saline, then report
BApply antibiotic eye drops and tell no one
CRub the eyes gently with a clean, dry tissue to remove the blood first
DFinish the procedure, then report it the next day
16.Infection control & patient safetyHard
During flu season, a nurse wakes up with fever, cough and muscle aches. What is the best action?
AGo to work but wear a surgical mask for the whole shift
BStay home and inform the employer according to the illness policy
CGo to work but avoid caring for patients who have weak immune systems
DTake an antipyretic so the fever does not show at work
17.Lab values & electrolytesMedium
How should a patient collect a clean-catch midstream urine sample?
AFill the cup completely, then add tap water if there is not enough
BClean the area, start voiding into the toilet, then catch the middle part
CCollect urine from the toilet bowl after voiding into the toilet
DCollect the very first urine of the stream directly in the sterile cup
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?
APast BCG vaccination only, with no infection
BLatent TB infection, which is not contagious
CA false result, as the test does not detect TB
DActive pulmonary TB, which is contagious
3Solutions
1.Nursing fundamentals
Answer: A · Group care and observations so patients are disturbed less often
Why this is the answer
Clustering care, dimming lights, reducing noise and offering eye masks or earplugs improve sleep. Sedatives carry risks and are not routine.
Answer
A · Group care and observations so patients are disturbed less often
2.Nursing fundamentals
Answer: A · Changes in breathing pattern, cool mottled skin and reduced intake
Why this is the answer
As death approaches, breathing may become irregular or noisy, the skin may become cool and mottled, and people eat and drink less and sleep more. Comfort, mouth care and family support become the focus.
Answer
A · Changes in breathing pattern, cool mottled skin and reduced intake
3.Clinical nursing
Answer: C · A recognised side effect of the ACE inhibitor
Why this is the answer
Dry cough is a common side effect of ACE inhibitors such as ramipril. An angiotensin II receptor blocker is often substituted.
Answer
C · A recognised side effect of the ACE inhibitor
4.Clinical nursing
Answer: D · "I only need to weigh myself once a month."
Why this is the answer
Daily weights at the same time with the same scales detect fluid retention early. A rapid gain, worsening breathlessness or needing more pillows should be reported.
Answer
D · "I only need to weigh myself once a month."
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 26.3 mmol/L
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.
Change in PaCO₂
|63 − 40| = 23 mmHg → 2.3 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 1·2.3 = 26.3 mmol/L
Answer
HCO₃⁻ = 26.3 mmol/L
6.Arterial blood gas interpretation
Answer: PaCO₂ = 50.4 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
0.7·42 + 21 = 50.4 mmHg
Answer
PaCO₂ = 50.4 mmHg
The rise has a limit: PaCO₂ rarely goes above about 55 mmHg from compensation alone.
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: says inappropriate, random words → 3
M: moves a hand to the site of pressure (localises) → 5
Add
GCS = 3 + 3 + 5 = 11
Severity
GCS 11 → moderate
Answer
moderate
8.Clinical assessment scores
Answer: low–medium
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 14/min → 0
SpO₂ 98% → 0
on air → 0
SBP 84 mmHg → 3
HR 76/min → 0
alert (A) → 0
T 38.1 °C → 1
Total and red scores
NEWS2 = 0 + 0 + 0 + 3 + 0 + 0 + 1 = 4
At least one parameter scores 3.
Risk group
low–medium
Answer
low–medium
A single score of 3 needs an urgent review even when the total is low.
9.Enteral & parenteral nutrition calculations
Answer: R = 73 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 = 30·88 = 2640 kcal/day
Daily volume
V = 2640/1.5 = 1760 mL/day
Pump rate
R = 1760/24 = 73.33 ≈ 73 mL/h
Answer
R = 73 mL/h
10.Enteral & parenteral nutrition calculations
Answer: GIR = 3.33 mg/kg/min
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.
Dextrose concentration
5% = 50 mg/mL
Dextrose per minute
50·50/60 = 41.67 mg/min
Per kilogram
GIR = 41.67/12.5 = 3.333 ≈ 3.33 mg/kg/min
Answer
GIR = 3.33 mg/kg/min
Shortcut: GIR = % dextrose × mL/h/(6 × kg).
11.ECG rhythm strip interpretation
Answer: sinus tachycardia
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: R–R = 12 small boxes, 1500 ÷ 12 ≈ 125 per minute.
2. Rhythm: regular, every R–R is 0.48 s.
3. P waves: upright, one before every QRS, all alike.
4. PR interval: 0.14 s, constant, within 0.12–0.20 s.
5. QRS: 0.06 s, narrow (below 0.12 s).
Interpretation
sinus tachycardia
Answer
sinus tachycardia
12.ECG rhythm strip interpretation
Answer: third-degree (complete) AV block
AV blocks: march out the P waves and check which ones are followed by a QRS. First-degree: every P conducted, PR constant and above 0.20 s. Second-degree type I (Mobitz I, Wenckebach): the PR lengthens from beat to beat until one P wave is not conducted, then the cycle starts again (group beating). Second-degree type II (Mobitz II): the PR of the conducted beats stays constant, and P waves are suddenly not conducted; the QRS is often wide. Third-degree (complete) block: P waves and QRS complexes are each regular but independent, the PR varies at random and the atrial rate is faster than the escape rate (junctional 40–60/min with a narrow QRS, ventricular 20–40/min with a wide QRS). A 2:1 block cannot be called type I or type II from one strip.
Five steps
1. Rate: R–R = 41 small boxes, 1500 ÷ 41 ≈ 37 per minute.
2. Rhythm: R–R regular (1.64 s) and P–P regular (0.64 s), but the two are independent.
3. P waves: upright and regular at 94 per minute, but not linked to the QRS complexes; some hide in a QRS or a T wave.
4. PR interval: varies from beat to beat; there is no fixed relation.
5. QRS: 0.16 s, wide (0.12 s or more).
Interpretation
third-degree (complete) AV block
Answer
third-degree (complete) AV block
Type II and third-degree blocks are the ones that can suddenly progress, so textbooks rank them as more serious than type I.
13.Prioritization & delegation
Answer: A · Assess the location, character and onset of the pain and the vital signs
Why this is the answer
Assessment comes first, because severe pain may be a sign of a new complication such as bleeding or a heart attack. The assessment also guides which analgesic is appropriate.
Answer
A · Assess the location, character and onset of the pain and the vital signs
14.Prioritization & delegation
Answer: A · Call for emergency help at once and prepare for urgent surgery
Why this is the answer
Sudden severe back or abdominal pain with hypotension in a patient with an aneurysm suggests rupture, which is fatal without urgent surgery. The mass should not be palpated firmly.
Answer
A · Call for emergency help at once and prepare for urgent surgery
15.Infection control & patient safety
Answer: A · Rinse the eyes at once with plenty of water or saline, then report
Why this is the answer
Mucous membranes are rinsed straight away with plenty of water or saline, for example at an eyewash station. The exposure is reported immediately so the risk can be assessed and post-exposure treatment considered.
Answer
A · Rinse the eyes at once with plenty of water or saline, then report
16.Infection control & patient safety
Answer: B · Stay home and inform the employer according to the illness policy
Why this is the answer
Health care workers with signs of influenza should not work, because they can infect patients and colleagues. They follow the employer’s policy on when they may return.
Answer
B · Stay home and inform the employer according to the illness policy
17.Lab values & electrolytes
Answer: B · Clean the area, start voiding into the toilet, then catch the middle part
Why this is the answer
Cleaning the urethral area and discarding the first part of the stream reduce contamination from skin and urethral bacteria. The inside of the sterile container must not be touched, and the sample should reach the laboratory promptly.Checked against:Clean catch urine sample · MedlinePlus (NIH) (2024)
Answer
B · Clean the area, start voiding into the toilet, then catch the middle part
18.Lab values & electrolytes
Answer: B · 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)