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 should the opening of a stoma bag be cut?
AIn any shape, as long as the bag sticks
BTo fit closely around the stoma without pressing on it
CSmaller than the stoma so it grips it tightly
DMuch larger than the stoma so that the edge never rubs against it
2.Nursing fundamentalsHard
Which sequence of steps is correct when taking off personal protective equipment?
AGloves, then mask, then gown, then eye protection
BGloves, then eye protection, then gown, then mask
CGown, then mask, then gloves, then eye protection
DEye protection, then mask, then gown, then gloves
3.Clinical nursingMedium
What happens in third-degree (complete) heart block?
AEvery impulse reaches the ventricles, but each one is slightly delayed
BThe atria beat chaotically with no P waves, and the ventricular rate is irregular
CThe ventricles beat very fast and regularly
DNo impulses from the atria reach the ventricles, so they beat independently
4.Clinical nursingHard
A patient suddenly develops a severe "worst ever" headache that reached full intensity within seconds, followed by vomiting and neck stiffness. What should be suspected?
ASubarachnoid haemorrhage
BSinusitis
CMigraine with aura in a known migraine sufferer
DTension headache
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 32 mmHg (4.3 kPa). Use the rule that in chronic respiratory alkalosis HCO₃⁻ falls by 5 mmol/L for every 10 mmHg that PaCO₂ is below 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.
A practice gas shows a metabolic alkalosis with HCO₃⁻ 36 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 36 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 spontaneously, talks in sentences but is confused and shows as the best motor response: withdraws the limb from pressure (normal flexion). 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 20/min, SpO₂ 98% on room air, blood pressure 100/60 mmHg, pulse 64/min, alert, temperature 37.2 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). A 55 kg patient has a fluid goal of 30 mL/kg/day and receives all fluid through a feeding tube. The formula is 81% free water and runs at 55 mL/h for 24 hours a day. The rest of the fluid is given as water flushes every 4 hours. What volume V is each flush? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). A child who weighs 13 kg receives 10% dextrose at 54 mL/h. Find the glucose infusion rate GIR in mg/kg/min. Round to two decimal places.
13 kg10%54 mL/h
GIR = mg/kg/min
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 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)
2sinus bradycardia
3second-degree AV block type II
4third-degree (complete) AV block
13.Prioritization & delegationMedium
A patient is receiving a blood transfusion. Which task can the nurse delegate to a nursing assistant?
AMeasuring and reporting vital signs at the times set by the nurse
BDeciding whether to stop the transfusion if the patient has chills
CAssessing the patient for signs of a transfusion reaction
DStarting the transfusion once the blood arrives
14.Prioritization & delegationHard
Using ESI, a stable adult with abdominal pain will need blood tests and a CT scan, but has a heart rate of 130/min. Which statement is correct?
AThe patient is level 4 because the blood tests and the scan count as one resource
BThe patient is level 5 because the pain is not severe
CVital signs never change the ESI level
DThe nurse should consider level 2 because of the danger-zone vital sign
15.Infection control & patient safetyMedium
An order reads “Give potassium chloride by IV push.” What should the nurse do?
ANot give it, and contact the prescriber, because it is never given by IV push
BDilute it in a small syringe and push it
CGive it slowly by IV push over two minutes while watching the cardiac monitor
DGive half by IV push and the rest later
16.Infection control & patient safetyHard
A nurse teaches a patient about care of a surgical incision at home. Which statement shows a need for further teaching?
A“I will wash my hands with soap before I touch or change the dressing.”
B“I will keep the dressing clean and dry as I was shown.”
C“If the wound gets red and drains pus, I will wait for my appointment next month.”
D“I will call the clinic if I get a fever or more pain around the wound.”
17.Lab values & electrolytesMedium
A patient with type 1 diabetes has the flu, is eating little and has a glucose of 290 mg/dL (16.1 mmol/L). Which advice is correct?
AStop all insulin until you are eating normally again
BDrink only water and avoid all carbohydrate foods
CWait 3 days before checking the glucose again
DKeep taking insulin and check blood or urine ketones
18.Lab values & electrolytesHard
A patient with metastatic breast cancer has a calcium of 13.2 mg/dL (3.3 mmol/L), is confused and constipated. Which prescribed treatment would the nurse expect to start first?
AIV 0.9% sodium chloride
BA thiazide diuretic
CStrict bed rest
DOral calcium supplements
3Solutions
1.Nursing fundamentals
Answer: B · To fit closely around the stoma without pressing on it
Why this is the answer
The opening should fit snugly so stoma output does not reach the skin, but not so tight that it damages the stoma. Stomas shrink in the weeks after surgery, so the size is re-measured.
Answer
B · To fit closely around the stoma without pressing on it
2.Nursing fundamentals
Answer: B · Gloves, then eye protection, then gown, then mask
Why this is the answer
In the CDC sequence, gloves (most contaminated) come off first, then goggles or face shield, then the gown, and finally the mask or respirator after leaving the room, with hand hygiene whenever hands become contaminated and at the end. Gown and gloves may also be removed together.
Answer
B · Gloves, then eye protection, then gown, then mask
3.Clinical nursing
Answer: D · No impulses from the atria reach the ventricles, so they beat independently
Why this is the answer
In complete heart block the atria and ventricles are dissociated, and a slow escape rhythm drives the ventricles. Patients may be dizzy or collapse and often need pacing.
Answer
D · No impulses from the atria reach the ventricles, so they beat independently
4.Clinical nursing
Answer: A · Subarachnoid haemorrhage
Why this is the answer
A sudden thunderclap headache suggests bleeding into the subarachnoid space, often from a ruptured aneurysm. It needs an urgent CT scan and neurosurgical input.
Answer
A · Subarachnoid haemorrhage
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 20 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
|32 − 40| = 8 mmHg → 0.8 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 − 5·0.8 = 20 mmol/L
Answer
HCO₃⁻ = 20 mmol/L
6.Arterial blood gas interpretation
Answer: PaCO₂ = 46.2 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
0.7·36 + 21 = 46.2 mmHg
Answer
PaCO₂ = 46.2 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 spontaneously → 4
V: talks in sentences but is confused → 4
M: withdraws the limb from pressure (normal flexion) → 4
Add
GCS = 4 + 4 + 4 = 12
Severity
GCS 12 → moderate
Answer
moderate
8.Clinical assessment scores
Answer: low
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 20/min → 0
SpO₂ 98% → 0
on air → 0
SBP 100 mmHg → 2
HR 64/min → 0
alert (A) → 0
T 37.2 °C → 0
Total and red scores
NEWS2 = 0 + 0 + 0 + 2 + 0 + 0 + 0 = 2
No parameter scores 3.
Risk group
low
Answer
low
9.Enteral & parenteral nutrition calculations
Answer: V = 97 mL
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.
Fluid goal
30·55 = 1650 mL/day
Free water from the formula
55·24 = 1320 mL
1320·0.81 = 1069 mL
Water still needed
1650 − 1069 = 580.8 mL/day
Volume per flush
24/4 = 6 flushes
V = 580.8/6 = 96.8 ≈ 97 mL
Answer
V = 97 mL
10.Enteral & parenteral nutrition calculations
Answer: GIR = 6.92 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
10% = 100 mg/mL
Dextrose per minute
100·54/60 = 90 mg/min
Per kilogram
GIR = 90/13 = 6.923 ≈ 6.92 mg/kg/min
Answer
GIR = 6.92 mg/kg/min
Shortcut: GIR = % dextrose × mL/h/(6 × kg).
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 = 11.5 × 0.04 = 0.46 s
RR = 22 × 0.04 = 0.88 s
Bazett’s formula
QTc = 0.46/√0.88 = 0.46/0.9381 = 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: second-degree AV block type II
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: 4 QRS complexes in 6 s, × 10 = 40 per minute.
2. Rhythm: the P waves are regular; R–R is regular except for a long pause where a QRS is missing.
3. P waves: upright and regular (P–P 0.96 s, 63 per minute); one P in every 3 is not followed by a QRS.
4. PR interval: constant at 0.24 s in the conducted beats.
5. QRS: 0.10 s, narrow (below 0.12 s).
Interpretation
second-degree AV block type II
Answer
second-degree AV block type II
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 · Measuring and reporting vital signs at the times set by the nurse
Why this is the answer
An assistant can measure vital signs and report them. Assessing for a reaction, starting the transfusion and deciding to stop it need the nurse’s judgement.
Answer
A · Measuring and reporting vital signs at the times set by the nurse
14.Prioritization & delegation
Answer: D · The nurse should consider level 2 because of the danger-zone vital sign
Why this is the answer
In ESI, a patient who needs two or more resources is level 3, but danger-zone vital signs such as a very fast heart rate should make the nurse consider level 2.
Answer
D · The nurse should consider level 2 because of the danger-zone vital sign
15.Infection control & patient safety
Answer: A · Not give it, and contact the prescriber, because it is never given by IV push
Why this is the answer
Potassium chloride given by IV push can cause fatal cardiac arrhythmias and arrest. It is only given diluted by controlled infusion, so the nurse does not give it and contacts the prescriber.
Answer
A · Not give it, and contact the prescriber, because it is never given by IV push
16.Infection control & patient safety
Answer: C · “If the wound gets red and drains pus, I will wait for my appointment next month.”
Why this is the answer
Increasing redness, purulent drainage, fever and worsening pain are signs of surgical site infection and should be reported promptly. Waiting a month could allow the infection to spread.
Answer
C · “If the wound gets red and drains pus, I will wait for my appointment next month.”
17.Lab values & electrolytes
Answer: D · Keep taking insulin and check blood or urine ketones
Why this is the answer
During illness, stress hormones raise glucose, so insulin is continued even when eating less. Glucose and ketones are checked often, fluids are taken, and the provider is contacted if ketones are moderate or high or vomiting prevents fluids.Checked against:Diabetes - when you are sick · MedlinePlus (NIH) (2026)
Answer
D · Keep taking insulin and check blood or urine ketones
18.Lab values & electrolytes
Answer: A · IV 0.9% sodium chloride
Why this is the answer
Hypercalcemia causes large urine volumes and dehydration. IV saline restores volume and helps the kidneys excrete calcium; bisphosphonates usually follow. Thiazides reduce calcium excretion, and immobility releases calcium from bone.Checked against:Hypercalcemia · MedlinePlus (NIH) (2026)