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
When may a nurse share confidential information without the patient's consent?
AWhen a colleague on another ward is curious
BWhen a journalist asks about a famous patient
CWhen it is needed to protect someone from a risk of serious harm
DWhenever a relative asks for it
2.Nursing fundamentalsHard
A patient has been taught to walk with underarm crutches. Which statement shows a need for further teaching?
A"I'll rest my weight on the tops of the crutches under my arms."
B"I'll take my weight through my hands on the hand grips."
C"I'll keep the crutch tips about a step out to the side and front."
D"I'll check the rubber tips regularly for wear."
3.Clinical nursingMedium
Which equipment must always be kept at the bedside of a patient with a tracheostomy?
AA blood glucose meter and a spare urinary catheter of the same size
BA blood pressure cuff and a spare nasal cannula and oxygen mask only
CSpare tracheostomy tubes, including one a size smaller, and working suction
DA peak flow meter and a nebuliser
4.Clinical nursingHard
Shortly after starting a transfusion, a patient becomes breathless, wheezy and hypotensive with facial swelling. What should the nurse do first?
AGive paracetamol and an antihistamine and continue the transfusion
BStop the transfusion, keep IV access and call for urgent help
CSlow the transfusion rate and recheck the observations in an hour
DFinish the unit quickly so the exposure time is as short as possible
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 73 mmHg (9.7 kPa). Use the rule that in chronic respiratory acidosis HCO₃⁻ rises by 3.5 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 respiratory acidosis: pH 7.32, PaCO₂ 71 mmHg (9.5 kPa), HCO₃⁻ 35 mmol/L. Use the rules ‘HCO₃⁻ rises 1 mmol/L per 10 mmHg (acute) or 3.5 mmol/L per 10 mmHg (chronic)’ to classify it. Click your answer.
pH 7.32PaCO₂ 71 mmHg (9.5 kPa)HCO₃⁻ 35 mmol/L
1acute
2chronic
3acute on chronic
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice patient is assessed with the Morse fall scale: history of falling in the last 3 months: no; secondary diagnosis: no; ambulatory aid: none, bed rest or nurse assists; IV therapy or saline lock: yes; gait: weak; mental status: knows own limits. Find the Morse total MFS.
0–125
MFS =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). An adult weighs 66 kg and is 175 cm tall. Calculate the BMI and click the WHO weight category.
Practice exercise (made-up values, not clinical guidance). A 75 kg patient has a fluid goal of 30 mL/kg/day and receives all fluid through a feeding tube. The formula is 84% free water and runs at 75 mL/h for 24 hours a day. The rest of the fluid is given as water flushes every 8 hours. What volume V is each flush? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1500 mL of parenteral nutrition with final concentrations of 10% dextrose and 5% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
1500 mLdextrose 10%amino acids 5%lipid 250 mL · 1.1 kcal/mL
E = kcal/day
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
1accelerated junctional rhythm
2supraventricular tachycardia (SVT)
3atrial fibrillation
4sinus tachycardia
12.ECG rhythm strip interpretationHard
A monitored patient is found unresponsive and not breathing normally, and no carotid pulse can be felt. The monitor shows this organised rhythm. What is this situation called? 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
1pulseless electrical activity (PEA)
2ventricular fibrillation
3asystole
4sinus tachycardia
13.Prioritization & delegationMedium
On a postpartum unit, which patient is the most appropriate to assign to an LPN/LVN?
ADay 1 after an uncomplicated vaginal birth, stable vital signs
BSevere pre-eclampsia on a magnesium sulfate infusion
CA new admission transferred from the labor ward with a fever of 38.6 °C
DOne hour after birth with heavy bleeding and a boggy uterus
14.Prioritization & delegationHard
A patient with a central venous catheter suddenly becomes breathless, with chest pain and a falling SpO₂, as the line is being removed. What does the nurse do first?
AAsk the patient to take slow deep breaths and continue
BFlush the catheter with saline to clear any blockage
CSit the patient upright and finish removing the line quickly
DCover the site, turn onto the left side head down, give oxygen and call for help
15.Infection control & patient safetyMedium
Which statement about the use of physical restraints is correct?
ARestraints can be used whenever the unit is short of nursing staff
BStanding as-needed restraint orders are good practice
CRestraints are checked once at the end of each shift
DAlternatives come first, and a time-limited order is needed
16.Infection control & patient safetyHard
During a disaster, the hospital needs to free beds quickly. Which patient is the best candidate for early discharge?
AA patient on an IV heparin infusion that is still being adjusted
BA patient admitted overnight for observation who is now stable with normal tests
CA patient on a ventilator in the intensive care unit who is slowly improving
DA patient with ongoing chest pain awaiting cardiac tests
17.Lab values & electrolytesMedium
Why must a low total calcium be interpreted with care in a patient with a low serum albumin?
ALow albumin makes every calcium test inaccurate and useless
BMuch calcium is bound to albumin, so total calcium falls even if ionized calcium is normal
CLow albumin always causes true, symptomatic hypocalcemia
DAlbumin and calcium are measured with the same chemical reaction, so they always fall together
18.Lab values & electrolytesHard
A patient with a long-standing lung condition has a serum bicarbonate of 32 mEq/L, an arterial PaCO₂ that is always high and a pH of 7.36. Which condition fits best?
AAcute diabetic ketoacidosis with severe dehydration and vomiting
BCOPD with chronic CO₂ retention and metabolic compensation
CAcute severe diarrhea with large bicarbonate losses
DAcute aspirin overdose with rapid breathing
3Solutions
1.Nursing fundamentals
Answer: C · When it is needed to protect someone from a risk of serious harm
Why this is the answer
Confidentiality can be broken without consent when required by law or when there is a serious risk of harm to the patient or others. Only the necessary information is shared, with the right people.
Answer
C · When it is needed to protect someone from a risk of serious harm
2.Nursing fundamentals
Answer: A · "I'll rest my weight on the tops of the crutches under my arms."
Why this is the answer
Leaning on the armpits can damage the brachial plexus and cause crutch palsy. Weight is taken through the hands, with a gap of a few finger-widths between the crutch top and the armpit.
Answer
A · "I'll rest my weight on the tops of the crutches under my arms."
3.Clinical nursing
Answer: C · Spare tracheostomy tubes, including one a size smaller, and working suction
Why this is the answer
Emergency equipment such as spare tubes (same size and one smaller), suction, oxygen and tracheal dilators must be at the bedside. This allows rapid management of a blocked or displaced tube.
Answer
C · Spare tracheostomy tubes, including one a size smaller, and working suction
4.Clinical nursing
Answer: B · Stop the transfusion, keep IV access and call for urgent help
Why this is the answer
Severe transfusion reactions, including anaphylaxis, require immediately stopping the transfusion, keeping venous access, following the ABCDE approach and treating anaphylaxis with IM adrenaline.
Answer
B · Stop the transfusion, keep IV access and call for urgent help
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 35.55 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
|73 − 40| = 33 mmHg → 3.3 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 3.5·3.3 = 35.55 mmol/L
Answer
HCO₃⁻ = 35.55 mmol/L
6.Arterial blood gas interpretation
Answer: chronic
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 HCO₃⁻
acute: 24 + 1·3.1 = 27.1 mmol/L
chronic: 24 + 3.5·3.1 = 34.85 mmol/L
Compare
measured: 35 mmol/L → chronic
Answer
chronic
7.Clinical assessment scores
Answer: MFS = 30
Morse fall scale: six items. History of falling: no 0, yes 25. Secondary diagnosis: no 0, yes 15. Ambulatory aid: none, bed rest or nurse assistance 0; crutches, cane or walker 15; holding on to furniture 30. IV therapy or saline lock: no 0, yes 20. Gait: normal, bed rest or wheelchair 0; weak 10; impaired 20. Mental status: knows own limits 0; overestimates or forgets limits 15. The total runs from 0 to 125. Risk cut-offs differ between hospitals; a common set is 0–24 low, 25–44 moderate and 45 or more high.
Score each item
history of falling in the last 3 months: no → 0
secondary diagnosis: no → 0
ambulatory aid: none, bed rest or nurse assists → 0
IV therapy or saline lock: yes → 20
gait: weak → 10
mental status: knows own limits → 0
Add
Morse total = 0 + 0 + 0 + 20 + 10 + 0 = 30
Answer
MFS = 30
8.Clinical assessment scores
Answer: healthy weight
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 = 66/1.75² = 21.55
Category
healthy weight
Answer
healthy weight
9.Enteral & parenteral nutrition calculations
Answer: V = 246 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
30·75 = 2250 mL/day
Free water from the formula
75·24 = 1800 mL
1800·0.84 = 1512 mL
Water still needed
2250 − 1512 = 738 mL/day
Volume per flush
24/8 = 3 flushes
V = 738/3 = 246 mL
Answer
V = 246 mL
10.Enteral & parenteral nutrition calculations
Answer: E = 1085 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: 10·1500/100 = 150 g
amino acids: 5·1500/100 = 75 g
Kilocalories per component
dextrose: 150·3.4 = 510 kcal
amino acids: 75·4 = 300 kcal
lipid: 250·1.1 = 275 kcal
Total energy
E = 510 + 300 + 275 = 1085 kcal/day
Answer
E = 1085 kcal/day
11.ECG rhythm strip interpretation
Answer: supraventricular tachycardia (SVT)
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. 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).
Five steps
1. Rate: R–R = 8 small boxes, 1500 ÷ 8 ≈ 188 per minute.
2. Rhythm: regular, every R–R is 0.32 s.
3. P waves: none visible; at this rate they are hidden in the QRS complexes or the T waves.
4. PR interval: not measurable.
5. QRS: 0.06 s, narrow (below 0.12 s), so the rhythm starts above the ventricles.
Interpretation
supraventricular tachycardia (SVT)
Answer
supraventricular tachycardia (SVT)
12.ECG rhythm strip interpretation
Answer: pulseless electrical activity (PEA)
Pulseless electrical activity (PEA): PEA cannot be seen on a strip. The monitor shows organised electrical activity (a rhythm other than VF, VT or asystole) but the patient has no palpable pulse, so it is recognised by checking the patient. In adult resuscitation guidelines PEA and asystole are the non-shockable cardiac arrest rhythms: high-quality CPR, epinephrine as soon as possible and a search for reversible causes (the Hs and Ts, such as hypovolaemia, hypoxia, tension pneumothorax and cardiac tamponade). VF and pulseless VT are the shockable rhythms.
What the strip shows
1. Rate: R–R = 14 small boxes, 1500 ÷ 14 ≈ 107 per minute.
2. Rhythm: regular, every R–R is 0.56 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: 0.08 s, narrow (below 0.12 s).
sinus tachycardia
What the patient shows
no pulse despite organised electrical activity: pulseless electrical activity (PEA), a non-shockable cardiac arrest rhythm
Answer
pulseless electrical activity (PEA)
Answer
pulseless electrical activity (PEA)
PEA is recognised at the bedside, never from the strip alone. This is exam practice, not clinical guidance.
13.Prioritization & delegation
Answer: A · Day 1 after an uncomplicated vaginal birth, stable vital signs
Why this is the answer
A stable patient after an uncomplicated birth fits the LPN/LVN role. Heavy bleeding, magnesium infusions and new admissions with fever need RN assessment.
Answer
A · Day 1 after an uncomplicated vaginal birth, stable vital signs
14.Prioritization & delegation
Answer: D · Cover the site, turn onto the left side head down, give oxygen and call for help
Why this is the answer
These signs during line removal suggest an air embolism. Covering the site with an airtight dressing stops more air entering, and the left side, head-down position helps trap air in the right side of the heart, away from the pulmonary artery. Oxygen and urgent help follow.
Answer
D · Cover the site, turn onto the left side head down, give oxygen and call for help
15.Infection control & patient safety
Answer: D · Alternatives come first, and a time-limited order is needed
Why this is the answer
Restraints are used only when other measures have failed and the patient or others are at risk. An order that is time-limited and regularly reviewed is needed, “as needed” orders are not allowed, and the patient is monitored often.
Answer
D · Alternatives come first, and a time-limited order is needed
16.Infection control & patient safety
Answer: B · A patient admitted overnight for observation who is now stable with normal tests
Why this is the answer
In a surge, stable patients who could be safely cared for at home are discharged first. Patients who are unstable or need close monitoring or titrated infusions must stay.
Answer
B · A patient admitted overnight for observation who is now stable with normal tests
17.Lab values & electrolytes
Answer: B · Much calcium is bound to albumin, so total calcium falls even if ionized calcium is normal
Why this is the answer
About 40–45% of calcium is bound to plasma proteins, mainly albumin. When albumin is low, total calcium falls although ionized calcium may be normal. A corrected calcium or a measured ionized calcium gives the true picture.Checked against:Hypocalcemia (StatPearls) · StatPearls (NCBI Bookshelf) (2026)
Answer
B · Much calcium is bound to albumin, so total calcium falls even if ionized calcium is normal
18.Lab values & electrolytes
Answer: B · COPD with chronic CO₂ retention and metabolic compensation
Why this is the answer
In chronic CO₂ retention, as in severe COPD, the kidneys retain bicarbonate over days and bring the pH back towards normal, often to the low end of the range. DKA and diarrhea lower bicarbonate, and aspirin overdose causes rapid breathing that lowers the PaCO₂.Checked against:Respiratory Acidosis · StatPearls (NCBI Bookshelf)
Answer
B · COPD with chronic CO₂ retention and metabolic compensation