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
Which Glasgow Coma Scale score indicates a fully alert patient?
A10
B15
C12
D3
2.Nursing fundamentalsHard
An older woman has been lying on the floor at home all night after a fall. Which complications should the nurse look for in particular?
AHigh blood sugar and a raised temperature from lying still
BHair loss and nail damage
CSunburn and dehydration from sweating
DPressure damage, hypothermia and muscle breakdown
3.Clinical nursingMedium
Which measure helps reduce the risk of surgical site infection?
AShaving the area with a razor the night before surgery
BChanging the wound dressing every hour
CLeaving the patient cool during surgery to slow bacterial growth
DRemoving hair, if needed, with clippers rather than a razor
4.Clinical nursingHard
A patient with severe ulcerative colitis develops abdominal distension, fever and tachycardia, and the number of stools falls. What complication should be suspected?
ARecovery from the colitis
BConstipation from dehydration
CToxic megacolon
DCoeliac disease
5.Arterial blood gas interpretationMedium
A practice gas shows a metabolic acidosis with HCO₃⁻ 6 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.
HCO₃⁻ 6 mmol/L
PaCO₂ = mmHg
6.Arterial blood gas interpretationHard
A practice gas shows pH 7.25, PaCO₂ 26 mmHg (3.5 kPa) and HCO₃⁻ 11 mmol/L, with Na⁺ 132 and Cl⁻ 92 mmol/L. Use the anion gap and the delta ratio to click the best interpretation.
Practice exercise (made-up values, not clinical guidance). A practice patient is assessed with the Braden scale: sensory perception: completely limited; moisture: constantly moist; activity: bedfast; mobility: very limited; nutrition: very poor; friction and shear: potential problem. Find the Braden total B.
6–23
B =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). An adult weighs 119 kg and is 183 cm tall. Calculate the BMI and click the WHO weight category.
Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a man who is 193 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 2400 mL of parenteral nutrition with final concentrations of 12.5% dextrose and 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 12.5%amino acids 5%lipid 250 mL · 2 kcal/mL
NPC = kcal/day
11.ECG rhythm strip interpretationMedium
Measure the QT interval and the R–R interval on this regular lead II strip, then calculate the rate-corrected QTc with Bazett’s formula QTc = QT/√RR (both in seconds). Give the answer in seconds to three decimals.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
QTc = s
12.ECG rhythm strip interpretationHard
This lead II strip shows second-degree AV block type I (Wenckebach). Measure the PR interval of the last conducted beat before a non-conducted P wave (the longest PR), in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
longest PR = s
13.Prioritization & delegationMedium
A patient is booked for a CT scan with iodinated contrast. Which of the patient’s medications may need to be held according to protocol?
ALevothyroxine
BAcetaminophen (paracetamol)
COmeprazole
DMetformin
14.Prioritization & delegationHard
A patient is receiving parenteral nutrition through a central line. Which finding needs immediate action?
AA glucose of 150 mg/dL (8.3 mmol/L) while the infusion is running
BSweating, shakiness and a glucose of 62 mg/dL (3.4 mmol/L) after the infusion stopped unexpectedly
CA dry, intact dressing over the line
DA weight gain of 0.2 kg since yesterday
15.Infection control & patient safetyMedium
A patient walking with a gait belt suddenly starts to fall. What should the nurse do?
APull the patient backwards quickly toward the bed
BLet go of the belt and run to call for help
CGrab the patient under both arms and try hard to keep them standing up
DHold the belt, widen the stance and ease the patient gently to the floor
16.Infection control & patient safetyHard
A patient on a general ward for two days is found to have smear-positive pulmonary TB. What should the nurse do besides moving the patient to an airborne isolation room?
AClose the ward to all new admissions for a full year
BTell all the exposed patients to start TB drugs at once, before any testing
CInform infection prevention so exposed patients and staff can be identified and followed up
DNothing more, because the patient has now been isolated
17.Lab values & electrolytesMedium
A patient is starting dabigatran, a direct oral anticoagulant. Which laboratory test is most important to review before the first dose?
ALipase, to rule out an inflamed pancreas first
BKidney function (creatinine clearance)
CINR, to set the dose of the anticoagulant
DTSH, to rule out an overactive thyroid gland
18.Lab values & electrolytesHard
A patient recovering from acute tubular necrosis now passes 4–5 L of urine a day. Which electrolyte changes should the nurse watch for?
ALow potassium and low sodium from urine losses
BHigh calcium and high phosphate from bone loss
CHigh potassium and high sodium from retention
DNo changes, because the kidneys are now normal
3Solutions
1.Nursing fundamentals
Answer: B · 15
Why this is the answer
The GCS ranges from 3 (deep coma) to 15 (fully alert). A score of 8 or less usually means the airway is at risk.
Answer
B · 15
2.Nursing fundamentals
Answer: D · Pressure damage, hypothermia and muscle breakdown
Why this is the answer
A long lie causes pressure injury, hypothermia, dehydration and rhabdomyolysis, which can damage the kidneys. The patient is assessed carefully for these as well as for fractures.
Answer
D · Pressure damage, hypothermia and muscle breakdown
3.Clinical nursing
Answer: D · Removing hair, if needed, with clippers rather than a razor
Why this is the answer
Razors cause micro-abrasions that increase infection risk, so hair is removed only if necessary with clippers just before surgery. Keeping patients warm and good skin preparation also help.
Answer
D · Removing hair, if needed, with clippers rather than a razor
4.Clinical nursing
Answer: C · Toxic megacolon
Why this is the answer
Toxic megacolon is acute dilatation of the inflamed colon with systemic toxicity, and it can perforate. Reduced stool frequency with worsening distension is a warning sign needing urgent surgical review.
Answer
C · Toxic megacolon
5.Arterial blood gas interpretation
Answer: PaCO₂ = 17 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.
Winter’s formula
PaCO₂ = 1.5·6 + 8 = 17 mmHg
range: 15–19 mmHg
Answer
PaCO₂ = 17 mmHg
6.Arterial blood gas interpretation
Answer: pure high-gap acidosis
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.
Anion gap
AG = 132 − (92 + 11) = 29
Delta ratio
(29 − 12)/(24 − 11) = 1.308
pure high-gap acidosis
Answer
pure high-gap acidosis
7.Clinical assessment scores
Answer: B = 8
Braden scale: six subscales for pressure-injury risk. Sensory perception, moisture, activity, mobility and nutrition score 1 to 4, from the worst level (1) to no problem (4); friction and shear scores 1 to 3. The total runs from 6 to 23, and a lower total means a higher risk. Common bands: 19–23 not at risk, 15–18 mild risk, 13–14 moderate risk, 10–12 high risk and 9 or below very high risk.
Score each subscale
sensory perception: completely limited → 1
moisture: constantly moist → 1
activity: bedfast → 1
mobility: very limited → 2
nutrition: very poor → 1
friction and shear: potential problem → 2
Add
Braden total = 1 + 1 + 1 + 2 + 1 + 2 = 8
Answer
B = 8
8.Clinical assessment scores
Answer: obesity class II
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 = 119/1.83² = 35.53
Category
obesity class II
Answer
obesity class II
9.Enteral & parenteral nutrition calculations
Answer: IBW = 86.8 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
193 cm/2.54 = 75.98 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(75.98 − 60) = 86.76 ≈ 86.8 kg
Answer
IBW = 86.8 kg
10.Enteral & parenteral nutrition calculations
Answer: NPC = 1520 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: 12.5·2400/100 = 300 g
amino acids: 5·2400/100 = 120 g
Kilocalories per component
dextrose: 300·3.4 = 1020 kcal
amino acids: 120·4 = 480 kcal
lipid: 250·2 = 500 kcal
Non-protein energy
NPC = 1020 + 500 = 1520 kcal/day
Answer
NPC = 1520 kcal/day
11.ECG rhythm strip interpretation
Answer: QTc = 0.49 s
QT and QTc: the QT interval runs from the start of the QRS complex to the end of the T wave. It shortens as the heart rate rises, so it is corrected for rate with the R–R interval in seconds: Bazett QTc = QT/√RR and Fridericia QTc = QT/∛RR. Bazett is the formula most textbooks use; it over-corrects at fast rates, where Fridericia is preferred. Limits differ between references: a QTc above about 0.45 s in men or 0.46 s in women is usually called prolonged, and above 0.50 s markedly prolonged.
Measure
QT = 12 × 0.04 = 0.48 s
RR = 24 × 0.04 = 0.96 s
Bazett’s formula
QTc = 0.48/√0.96 = 0.48/0.9798 = 0.49 s
Answer
QTc = 0.49 s
Above the usual limits for both men (about 0.45 s) and women (about 0.46 s): prolonged. (490 ms)
12.ECG rhythm strip interpretation
Answer:longest PR = 0.36 s
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.
March out the P waves
P–P = 0.88 s, regular; one P wave in every 4 is not conducted
PR in each group
PR₁ = 0.16 s, PR₂ = 0.28 s, PR₃ = 0.36 s
Answer
longest PR = 0.36 s
The biggest step in PR comes between the first and second beats of a group; later steps are smaller, which is why the R–R intervals shorten before the pause.
13.Prioritization & delegation
Answer: D · Metformin
Why this is the answer
If contrast causes kidney injury, metformin can build up and cause lactic acidosis. Protocols often hold metformin around the procedure, especially when kidney function is reduced.
Answer
D · Metformin
14.Prioritization & delegation
Answer: B · Sweating, shakiness and a glucose of 62 mg/dL (3.4 mmol/L) after the infusion stopped unexpectedly
Why this is the answer
Parenteral nutrition contains a lot of glucose, and the body responds with high insulin levels. If the infusion stops suddenly, rebound hypoglycemia can follow. The nurse treats the low glucose per protocol, informs the provider and follows the policy for an interrupted infusion. A modestly raised glucose, an intact dressing and a small weight change are expected or minor.
Answer
B · Sweating, shakiness and a glucose of 62 mg/dL (3.4 mmol/L) after the infusion stopped unexpectedly
15.Infection control & patient safety
Answer: D · Hold the belt, widen the stance and ease the patient gently to the floor
Why this is the answer
The nurse keeps hold of the gait belt, takes a wide base of support and slides the patient down along their own leg to the floor, protecting the head. This controls the fall and protects the nurse’s back.
Answer
D · Hold the belt, widen the stance and ease the patient gently to the floor
16.Infection control & patient safety
Answer: C · Inform infection prevention so exposed patients and staff can be identified and followed up
Why this is the answer
Infection prevention and public health carry out a contact investigation to identify and screen people exposed while the patient was not isolated. Treatment of contacts depends on their test results.
Answer
C · Inform infection prevention so exposed patients and staff can be identified and followed up
17.Lab values & electrolytes
Answer: B · Kidney function (creatinine clearance)
Why this is the answer
Dabigatran is excreted mainly by the kidneys, so poor kidney function raises the drug level and bleeding risk. Kidney function is checked before starting and regularly afterwards. Routine INR monitoring is not used for direct oral anticoagulants.Checked against:Dabigatran · MedlinePlus (NIH) (2025)
Answer
B · Kidney function (creatinine clearance)
18.Lab values & electrolytes
Answer: A · Low potassium and low sodium from urine losses
Why this is the answer
In the diuretic phase of AKI, the recovering tubules lose large amounts of water and electrolytes, so dehydration, hypokalemia and hyponatremia can occur. Daily weights, intake and output, and frequent electrolytes guide replacement.Checked against:Acute tubular necrosis · MedlinePlus (NIH) (2025)
Answer
A · Low potassium and low sodium from urine losses