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
The skin along a peripheral IV cannula is red, painful and swollen. What is the appropriate action?
ACover it with a fresh dressing and continue the infusion as prescribed
BFlush the cannula harder to clear it
CIncrease the infusion rate
DRemove the cannula and document it, then resite if still needed
2.Nursing fundamentalsHard
A patient taking furosemide has a serum potassium of 3.0 mmol/L (3.0 mEq/L). Why is this important?
ALoop diuretics cause potassium loss, and low levels can cause arrhythmias
BThe level is normal and needs no action
CLow potassium only causes mild thirst
DFurosemide raises potassium, so this level is falsely low and can be ignored
3.Clinical nursingMedium
Why are alternate sutures sometimes removed first when taking out stitches?
ATo check the wound stays closed before removing the rest
BTo reduce the cost of dressings
CTo make the procedure faster
DBecause the remaining sutures dissolve on their own within a day
4.Clinical nursingHard
A patient with a possible neck injury after a fall needs their airway opened. Which manoeuvre is preferred?
AHead tilt with chin lift
BHyperextending the neck
CJaw thrust
DTurning the head to one side
5.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.38, PaCO₂ 56 mmHg (7.5 kPa) and HCO₃⁻ 32 mmol/L. The primary disorder is respiratory acidosis. How far is it compensated? Click your answer.
pH 7.38PaCO₂ 56 mmHg (7.5 kPa)HCO₃⁻ 32 mmol/L
1uncompensated
2partially compensated
3fully compensated
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⁺ 135 and Cl⁻ 95 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: no impairment; moisture: rarely moist; activity: chairfast; mobility: very limited; nutrition: adequate; friction and shear: problem. Find the Braden total B.
6–23
B =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 12/min, SpO₂ 91% on room air, blood pressure 142/86 mmHg, pulse 50/min, alert, temperature 36.8 °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 1.2 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). Over 24 hours a patient receives 2000 mL of parenteral nutrition with final concentrations of 20% dextrose and 6% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
2000 mLdextrose 20%amino acids 6%lipid 250 mL · 1.1 kcal/mL
NPC = kcal/day
11.ECG rhythm strip interpretationMedium
This lead II strip shows atrial flutter. Measure the flutter-wave interval and find the atrial rate in beats per minute.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
atrial rate = bpm
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 on hemodialysis has an arteriovenous fistula in the left arm. Which instruction should the nurse give the nursing assistant?
AHelp the patient carry shopping bags on the left arm
BMeasure blood pressure on the left arm only, every 4 hours
CDo not measure blood pressure on the left arm
DKeep the left arm wrapped tightly in a bandage at night
14.Prioritization & delegationHard
A patient was knocked out briefly in a fall, then woke and talked normally. Two hours later the patient becomes drowsy and one pupil is larger. What is the most likely cause?
AA mild concussion that is settling
BLow blood sugar from missing a meal
CAn epidural hematoma
DNormal tiredness after a fall
15.Infection control & patient safetyMedium
Which equipment practice is correct for a patient on contact precautions?
ATaking the patient’s equipment to the next room
BUsing the same stethoscope for all patients without cleaning
CUsing a dedicated stethoscope and blood pressure cuff for that patient
DUsing equipment from the clean utility room and putting it back unchanged
16.Infection control & patient safetyHard
A visitor is receiving an electric shock from a faulty lamp and is still touching it. What should the nurse do first?
APull the visitor away from the lamp by the arm as quickly as possible
BSwitch off the power or unplug the lamp without touching the person
CThrow water over the lamp to stop the current
DStart chest compressions straight away
17.Lab values & electrolytesMedium
A patient with diabetes also takes propranolol. Why is regular glucose monitoring especially important?
AThe drug can mask warning signs of hypoglycemia
BThe drug stops the meter from reading correctly
CThe drug blocks the insulin injection site
DThe drug causes very high glucose in all patients
18.Lab values & electrolytesHard
A patient started methimazole for hyperthyroidism 6 weeks ago and now has a fever and a severe sore throat. Which action is most important?
AAdvise the patient to continue the drug and drink more fluid
BHold the drug and arrange an urgent white cell and neutrophil count
CCheck the TSH and double the dose if it is still low
DGive the next dose and suggest warm salt-water gargles for comfort
3Solutions
1.Nursing fundamentals
Answer: D · Remove the cannula and document it, then resite if still needed
Why this is the answer
Phlebitis is inflammation of the vein. The cannula should be removed, the site recorded and monitored, and a new cannula placed elsewhere only if it is still needed.
Answer
D · Remove the cannula and document it, then resite if still needed
2.Nursing fundamentals
Answer: A · Loop diuretics cause potassium loss, and low levels can cause arrhythmias
Why this is the answer
Furosemide increases potassium loss in the urine. Hypokalaemia causes muscle weakness and cardiac arrhythmias, so the result is reported and replacement considered.
Answer
A · Loop diuretics cause potassium loss, and low levels can cause arrhythmias
3.Clinical nursing
Answer: A · To check the wound stays closed before removing the rest
Why this is the answer
Removing alternate sutures allows the nurse to see whether the wound edges stay together. If they begin to separate, the remaining sutures can be left and the team informed.
Answer
A · To check the wound stays closed before removing the rest
4.Clinical nursing
Answer: C · Jaw thrust
Why this is the answer
A jaw thrust opens the airway with minimal neck movement. The cervical spine is protected with manual in-line stabilisation, although opening the airway still takes priority if it remains obstructed.
Answer
C · Jaw thrust
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 56 mmHg: high (35–45)
HCO₃⁻ 32 mmol/L: high (22–26)
Compensation
fully compensated
Answer
fully compensated
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 = 135 − (95 + 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 = 16
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: no impairment → 4
moisture: rarely moist → 4
activity: chairfast → 2
mobility: very limited → 2
nutrition: adequate → 3
friction and shear: problem → 1
Add
Braden total = 4 + 4 + 2 + 2 + 3 + 1 = 16
Answer
B = 16
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 12/min → 0
SpO₂ 91% → 3
on air → 0
SBP 142 mmHg → 0
HR 50/min → 1
alert (A) → 0
T 36.8 °C → 0
Total and red scores
NEWS2 = 0 + 3 + 0 + 0 + 1 + 0 + 0 = 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 = 92 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 = 2640/1.2 = 2200 mL/day
Pump rate
R = 2200/24 = 91.67 ≈ 92 mL/h
Answer
R = 92 mL/h
10.Enteral & parenteral nutrition calculations
Answer: NPC = 1635 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: 20·2000/100 = 400 g
amino acids: 6·2000/100 = 120 g
Kilocalories per component
dextrose: 400·3.4 = 1360 kcal
amino acids: 120·4 = 480 kcal
lipid: 250·1.1 = 275 kcal
Non-protein energy
NPC = 1360 + 275 = 1635 kcal/day
Answer
NPC = 1635 kcal/day
11.ECG rhythm strip interpretation
Answer: atrial rate = 250 bpm
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.
Flutter waves
F–F = 6 small boxes = 0.24 s → 1500 ÷ 6 = 250 per minute
QRS complexes
R–R = 24 small boxes = 0.96 s → 1500 ÷ 24 = 63 per minute
conduction ratio = 250 ÷ 63 = 4:1
Answer
atrial rate = 250 bpm
12.ECG rhythm strip interpretation
Answer:longest PR = 0.3 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 = 0.96 s, regular; one P wave in every 3 is not conducted
PR in each group
PR₁ = 0.16 s, PR₂ = 0.30 s
Answer
longest PR = 0.3 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: C · Do not measure blood pressure on the left arm
Why this is the answer
Blood pressure cuffs, tight bands and heavy loads can damage or block a fistula. The arm with the access is protected, and the nurse checks it for a thrill and bruit.
Answer
C · Do not measure blood pressure on the left arm
14.Prioritization & delegation
Answer: C · An epidural hematoma
Why this is the answer
An epidural hematoma often causes a brief loss of consciousness, a lucid interval, then rapid deterioration as arterial bleeding compresses the brain. It is a neurosurgical emergency.
Answer
C · An epidural hematoma
15.Infection control & patient safety
Answer: C · Using a dedicated stethoscope and blood pressure cuff for that patient
Why this is the answer
Non-critical equipment such as stethoscopes and cuffs is dedicated to the patient, or cleaned and disinfected before it is used for another patient.
Answer
C · Using a dedicated stethoscope and blood pressure cuff for that patient
16.Infection control & patient safety
Answer: B · Switch off the power or unplug the lamp without touching the person
Why this is the answer
The rescuer must not touch someone still in contact with live current. The power is switched off or the plug pulled first, then the person is assessed and resuscitation is started if needed.
Answer
B · Switch off the power or unplug the lamp without touching the person
17.Lab values & electrolytes
Answer: A · The drug can mask warning signs of hypoglycemia
Why this is the answer
Beta-blockers, especially nonselective ones, blunt adrenergic warning signs of hypoglycemia such as tremor and tachycardia, and they can delay recovery. Sweating usually remains. Glucose checks help detect lows that the patient may not feel.Checked against:Low blood sugar · MedlinePlus (NIH) (2026)
Answer
A · The drug can mask warning signs of hypoglycemia
18.Lab values & electrolytes
Answer: B · Hold the drug and arrange an urgent white cell and neutrophil count
Why this is the answer
Methimazole and propylthiouracil can cause agranulocytosis, often in the first months of therapy. Fever or sore throat must be reported at once; the drug is held and a CBC with differential is checked. Infection is treated urgently if neutrophils are low.
Answer
B · Hold the drug and arrange an urgent white cell and neutrophil count