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?
ADo routine tasks such as bed changes at midnight while it is quiet
BKeep the main lights on so staff can see clearly
CGroup care and observations so patients are disturbed less often
DGive every patient a sleeping tablet
2.Nursing fundamentalsHard
Which nursing diagnosis is written in the problem–aetiology–signs (PES) format?
AImpaired skin integrity related to immobility, as shown by a sacral wound
BPain related to pain, as shown by the patient saying that it hurts a lot
CPneumonia related to a bacterial infection in the right lung
DTurn the patient every two hours to protect the skin
3.Clinical nursingMedium
Which examination findings suggest a large pleural effusion on one side?
AWheeze heard over both lungs
BNormal breath sounds and normal percussion
CDull percussion and reduced breath sounds over the lung base
DA hyper-resonant chest with the trachea pulled towards that side
4.Clinical nursingHard
Which patient should a ward nurse assess first at the start of a shift?
AA patient with new-onset confusion and a respiratory rate of 28/min
BA patient awaiting discharge with stable observations
CA patient asking for a laxative
DA patient with chronic back pain scored 4/10
5.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.53, PaCO₂ 30 mmHg (4.0 kPa) and HCO₃⁻ 24 mmol/L. The primary disorder is respiratory alkalosis. How far is it compensated? Click your answer.
pH 7.53PaCO₂ 30 mmHg (4.0 kPa)HCO₃⁻ 24 mmol/L
1uncompensated
2partially compensated
3fully compensated
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). A patient has a pulse of 105/min and a blood pressure of 90/54 mmHg. Find the shock index SI = HR/SBP. Round to two decimal places.
HR 105/minBP 90/54 mmHg
SI =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 22/min, SpO₂ 99% on supplemental oxygen, blood pressure 102/62 mmHg, pulse 114/min, alert, temperature 35.8 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). A 78 kg patient needs 1.2 g of protein per kg a day. The tube feed contains 40 g of protein per litre and runs at 75 mL/h for 16 hours a day. How many grams of extra protein ΔP a day are still needed? Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1200 mL of parenteral nutrition with final concentrations of 17.5% dextrose and 4.25% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the non-protein kilocalorie to nitrogen ratio NPC : N (the number x in x : 1). Round to the nearest whole number.
1200 mLdextrose 17.5%amino acids 4.25%lipid 250 mL · 1.1 kcal/mL
NPC : N =
11.ECG rhythm strip interpretationMedium
This lead II strip shows sinus rhythm with one pause. Measure the pause, the R–R interval across it, in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
pause = s
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 II
2second-degree AV block type I (Wenckebach)
3junctional rhythm
4third-degree (complete) AV block
13.Prioritization & delegationMedium
A parent of a child with influenza talks with the nurse. Which statement shows a need for further teaching?
A“I will give my child plenty of fluids.”
B“I will keep my child home from school and away from others while unwell.”
C“I will call if my child has trouble breathing.”
D“I will give my child aspirin to bring the fever down.”
14.Prioritization & delegationHard
A patient with SIADH has a serum sodium of 120 mEq/L and is newly confused. Which nursing action has priority?
ASeizure precautions and close neurological checks
BEncouraging the patient to drink plenty of water
CTeaching the patient about a low-sodium diet at home
DHelping the patient to walk in the corridor alone
15.Infection control & patient safetyMedium
A patient in bed has a generalized tonic-clonic seizure. What should the nurse do?
AHold the arms and legs firmly to stop the movements
BTurn the patient on their side and protect them from injury without restraining
CPut a padded tongue blade between the teeth to protect the tongue from biting
DGive sips of water to keep the airway moist
16.Infection control & patient safetyHard
A patient after heart surgery has temporary epicardial pacing wires. Why do staff take special care with electrical safety?
AThe wires make the patient immune to electric shock
BElectrical safety only matters for patients who have permanent implanted pacemakers
CSmall currents can travel along the wires straight to the heart and cause arrhythmias
DPacing wires can only carry current coming from the pacemaker box itself
17.Lab values & electrolytesMedium
A patient scheduled for surgery this morning has a potassium of 3.0 mEq/L on pre-operative tests. What should the nurse do?
ASend the patient to surgery without comment
BGive an oral potassium dose without a prescription
CRepeat the test after the surgery is finished
DReport it to the surgical team before surgery
18.Lab values & electrolytesHard
A patient with a sodium of 132 mEq/L and blood glucose of 600 mg/dL (33.3 mmol/L) is admitted. Why is the sodium value interpreted with care?
AHigh glucose draws water into the blood, diluting the sodium
BHigh glucose raises the measured sodium falsely, so it is really lower
CThe sodium result must be a laboratory error
DGlucose has no effect on the measured sodium
3Solutions
1.Nursing fundamentals
Answer: C · 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
C · Group care and observations so patients are disturbed less often
2.Nursing fundamentals
Answer: A · Impaired skin integrity related to immobility, as shown by a sacral wound
Why this is the answer
A PES statement gives the nursing problem, the related cause and the defining signs. Pneumonia is a medical diagnosis, turning is an intervention, and a cause cannot repeat the problem.
Answer
A · Impaired skin integrity related to immobility, as shown by a sacral wound
3.Clinical nursing
Answer: C · Dull percussion and reduced breath sounds over the lung base
Why this is the answer
Fluid in the pleural space muffles breath sounds and makes percussion stony dull. A large effusion may push the trachea away from the affected side.
Answer
C · Dull percussion and reduced breath sounds over the lung base
4.Clinical nursing
Answer: A · A patient with new-onset confusion and a respiratory rate of 28/min
Why this is the answer
New confusion with tachypnoea suggests acute deterioration, such as sepsis or hypoxia. Patients with stable chronic problems can wait.
Answer
A · A patient with new-onset confusion and a respiratory rate of 28/min
5.Arterial blood gas interpretation
Answer: uncompensated
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 7.53: alkalaemia (above 7.45)
PaCO₂ 30 mmHg: low (35–45)
HCO₃⁻ 24 mmol/L: normal (22–26)
Compensation
uncompensated
Answer
uncompensated
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: SI = 1.17
Blood pressure values: pulse pressure PP = SBP − DBP. Mean arterial pressure MAP ≈ (SBP + 2·DBP)/3 = DBP + PP/3, an estimate based on the heart spending about two thirds of each beat in diastole at a normal heart rate (less accurate when the heart rate is fast); a MAP of at least about 65 mmHg is a common target for organ perfusion. The shock index SI = heart rate/SBP is normally about 0.5–0.7; a value above about 1 is a warning sign of shock.
Shock index
SI = 105/90 = 1.167 ≈ 1.17
Answer
SI = 1.17
1 or more: a warning sign of shock in this practice case.
8.Clinical assessment scores
Answer: high
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 22/min → 2
SpO₂ 99% → 0
on oxygen → 2
SBP 102 mmHg → 1
HR 114/min → 2
alert (A) → 0
T 35.8 °C → 1
Total and red scores
NEWS2 = 2 + 0 + 2 + 1 + 2 + 0 + 1 = 8
No parameter scores 3.
Risk group
high
Answer
high
A total of 5 or more calls for an urgent clinical response.
9.Enteral & parenteral nutrition calculations
Answer: ΔP = 45.6 g/day
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.
Protein needed
1.2·78 = 93.6 g/day
Protein from the feed
75·16 = 1200 mL = 1.2 L
1.2·40 = 48 g/day
Shortfall
ΔP = 93.6 − 48 = 45.6 g/day
Answer
ΔP = 45.6 g/day
10.Enteral & parenteral nutrition calculations
Answer: NPC : N = 121
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: 17.5·1200/100 = 210 g
amino acids: 4.25·1200/100 = 51 g
Kilocalories per component
dextrose: 210·3.4 = 714 kcal
amino acids: 51·4 = 204 kcal
lipid: 250·1.1 = 275 kcal
Non-protein kcal and nitrogen
NPC = 714 + 275 = 989 kcal
N = 51/6.25 = 8.16 g
Ratio
NPC : N = 989/8.16 = 121.2 ≈ 121 : 1
Answer
NPC : N = 121
Ratios of about 150 : 1 are typical for stable patients; lower ratios give relatively more protein.
11.ECG rhythm strip interpretation
Answer: pause = 1.52 s
Narrow-complex tachycardia and pauses: supraventricular tachycardia (SVT) is a regular tachycardia at about 150–250/min with narrow QRS complexes; the P waves are usually not visible because they are hidden in the QRS complex or the T wave. Sinus tachycardia in an adult at rest is usually below about 150/min and has a visible P wave before every QRS; atrial flutter with 2:1 conduction often runs at about 150/min and shows sawtooth waves. In sinus arrest the sinus node stops firing for a moment: a pause with no P wave and no QRS whose length is not a whole number of P–P cycles (a pause of exactly two or three cycles points to sinus exit block instead).
Measure
38 small boxes from R to R across the pause
Convert
pause = 38 × 0.04 s = 1.52 s
Compare with P–P
1.52 ÷ 0.88 ≈ 1.7 P–P cycles, not a whole number
Answer
pause = 1.52 s
No P wave appears in the pause, and the pause is not a whole number of P–P cycles: sinus arrest. A pause of exactly two or three cycles would point to sinus exit block.
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 = 28 small boxes, 1500 ÷ 28 ≈ 54 per minute.
2. Rhythm: R–R regular (1.12 s) and P–P regular (0.76 s), but the two are independent.
3. P waves: upright and regular at 79 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: 0.08 s, narrow (below 0.12 s).
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: D · “I will give my child aspirin to bring the fever down.”
Why this is the answer
Aspirin in children with viral illnesses such as influenza or chickenpox is linked to Reye syndrome. Fluids, rest at home and reporting breathing trouble are correct.
Answer
D · “I will give my child aspirin to bring the fever down.”
14.Prioritization & delegation
Answer: A · Seizure precautions and close neurological checks
Why this is the answer
Severe hyponatremia can cause seizures and falls. The nurse keeps the patient safe and reports changes; free water is restricted rather than encouraged, as prescribed.
Answer
A · Seizure precautions and close neurological checks
15.Infection control & patient safety
Answer: B · Turn the patient on their side and protect them from injury without restraining
Why this is the answer
The nurse stays with the patient, turns them to the side to keep the airway clear, moves hard objects away and times the seizure. Objects in the mouth and restraint can cause injury.
Answer
B · Turn the patient on their side and protect them from injury without restraining
16.Infection control & patient safety
Answer: C · Small currents can travel along the wires straight to the heart and cause arrhythmias
Why this is the answer
Wires that lead directly to the heart allow tiny currents (microshock) to reach the myocardium and cause ventricular fibrillation. Staff wear gloves when handling them, cover exposed ends and use properly grounded equipment.
Answer
C · Small currents can travel along the wires straight to the heart and cause arrhythmias
17.Lab values & electrolytes
Answer: D · Report it to the surgical team before surgery
Why this is the answer
Hypokalemia increases the risk of arrhythmias during anesthesia and can prolong muscle weakness. Abnormal pre-operative results are reported to the surgeon and anesthetist, who decide whether to correct it or delay surgery.Checked against:Hypokalemia · StatPearls (NCBI Bookshelf) (2025)
Answer
D · Report it to the surgical team before surgery
18.Lab values & electrolytes
Answer: A · High glucose draws water into the blood, diluting the sodium
Why this is the answer
High glucose draws water from the cells into the blood, lowering the measured sodium. As the glucose is treated, the sodium usually rises. A common correction adds about 1.6–2.4 mEq/L of sodium for every 100 mg/dL of glucose above 100 mg/dL.Checked against:Sodium blood test · MedlinePlus (NIH) (2025)
Answer
A · High glucose draws water into the blood, diluting the sodium