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 washing a patient's eyes, how should each eye be wiped?
AFrom the inner corner outwards, using a clean part of the cloth for each eye
BIn small circles over the closed eyelid of both eyes
CFrom the outer corner inwards, using the same part of the cloth for both
DOnly the eye that looks dirty needs cleaning
2.Nursing fundamentalsHard
A patient with delirium tries to leave the ward at night, saying they are going home, and would be at serious risk outside. What is correct (England and Wales)?
ALock them in a side room until the morning for their own safety
BGive a sedative without asking anyone
CAssess capacity and, if it is lacking, act in their best interests
DLet them leave, as all adults are free to go wherever they like
3.Clinical nursingMedium
Which group of features is typical of nephrotic syndrome?
ABlood in the urine, high blood pressure and reduced urine output only
BPolyuria, thirst and weight loss
CSevere loin pain and fever
DHeavy proteinuria, low serum albumin and oedema
4.Clinical nursingHard
Which drug group is first-line for a prolonged convulsive seizure?
ABenzodiazepines, such as buccal midazolam or IV lorazepam
BOpioids, such as morphine or diamorphine, given intravenously
CBeta-blockers, such as bisoprolol or atenolol
DAntihistamines, such as chlorphenamine
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 74 mmHg (9.9 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 pH 7.28, PaCO₂ 22 mmHg (2.9 kPa) and HCO₃⁻ 10 mmol/L, with Na⁺ 145 and Cl⁻ 113 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 Morse fall scale: history of falling in the last 3 months: yes; secondary diagnosis: yes; ambulatory aid: holds on to furniture; IV therapy or saline lock: no; gait: normal, bed rest or wheelchair; 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). A practice patient is assessed with the Braden scale: sensory perception: no impairment; moisture: rarely moist; activity: chairfast; mobility: slightly limited; nutrition: excellent; friction and shear: potential problem. Use the bands 19–23 not at risk, 15–18 mild, 13–14 moderate, 10–12 high and 9 or below very high. Click the risk level.
Practice exercise (made-up values, not clinical guidance). A woman is 183 cm tall and weighs 99 kg. Find the actual weight as a percentage of the ideal body weight, %IBW, using the Devine formula (1 in = 2.54 cm). Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). A 61 kg adult receives 1000 mL of parenteral nutrition containing 15% dextrose, infused over 18 hours. Find the glucose infusion rate GIR in mg/kg/min. Round to two decimal places.
61 kg1000 mLdextrose 15%18 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
A patient without a palpable pulse has this organised rhythm on the monitor (pulseless electrical activity). Which treatment do adult resuscitation guidelines name for 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
1CPR (non-shockable rhythm)
2synchronised cardioversion
3immediate defibrillation
4transcutaneous pacing
13.Prioritization & delegationMedium
Straight after birth, what is the first priority for a healthy-looking newborn?
ADry and warm the baby while checking that it is breathing
BGive the first bath to remove the blood and vernix
CGive the vitamin K injection before anything else is done
DWeigh and measure the baby on the scale
14.Prioritization & delegationHard
During a busy shift, four tasks are due. Which should the nurse do first?
AGive a routine daily vitamin tablet that is due at the same time
BHelp a stable patient fill in tomorrow’s menu card
CFirst dose of IV antibiotic for a patient with suspected sepsis
DUpdate the nursing care plan before the managers’ audit
15.Infection control & patient safetyMedium
A nurse pours sterile saline into a bowl on a sterile field. Which technique is correct?
APour from below the level of the field to reduce splashing
BReach across the field to fill the bowl at the far side
CRest the lip of the bottle on the edge of the bowl so that the saline does not splash
DHold the bottle with the label in the palm and pour without touching the bowl
16.Infection control & patient safetyHard
A patient on airborne precautions needs an urgent CT scan. Which plan is correct?
APatient goes unmasked, and the CT room is cleaned the next day
BPatient masked, CT warned in advance, staff in respirators
CPatient wears an N95 respirator, so staff need no protection
DThe scan is postponed until the patient is no longer infectious
17.Lab values & electrolytesMedium
A patient on digoxin has a level of 2.8 ng/mL and a heart rate of 52/min. What is the nurse’s best action?
AGive the dose, as the heart rate is above 50/min
BGive a double dose to correct the rhythm
CGive the dose and recheck the level in a month
DHold the dose and inform the prescriber
18.Lab values & electrolytesHard
A trauma patient receives many units of blood quickly and then develops muscle twitching and low blood pressure. Which laboratory value is most likely to explain this?
AA high serum magnesium
BA low serum glucose
CA low ionized calcium
DA high serum sodium
3Solutions
1.Nursing fundamentals
Answer: A · From the inner corner outwards, using a clean part of the cloth for each eye
Why this is the answer
Wiping from the inner to the outer canthus moves debris away from the tear duct. Using a clean part of the cloth for each eye prevents spreading infection between them.
Answer
A · From the inner corner outwards, using a clean part of the cloth for each eye
2.Nursing fundamentals
Answer: C · Assess capacity and, if it is lacking, act in their best interests
Why this is the answer
A delirious patient may lack capacity for this decision. Staff can take reasonable, proportionate steps in their best interests, such as calm persuasion and close supervision, while seeking medical review.
Answer
C · Assess capacity and, if it is lacking, act in their best interests
3.Clinical nursing
Answer: D · Heavy proteinuria, low serum albumin and oedema
Why this is the answer
In nephrotic syndrome, damaged glomeruli leak protein, so albumin falls and fluid moves into tissues, causing oedema. Cholesterol is often raised too.
Answer
D · Heavy proteinuria, low serum albumin and oedema
4.Clinical nursing
Answer: A · Benzodiazepines, such as buccal midazolam or IV lorazepam
Why this is the answer
Benzodiazepines enhance GABA and are first-line for seizures lasting over five minutes. If seizures continue, second-line antiepileptic drugs are given and senior help is needed.
Answer
A · Benzodiazepines, such as buccal midazolam or IV lorazepam
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 35.9 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
|74 − 40| = 34 mmHg → 3.4 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 3.5·3.4 = 35.9 mmol/L
Answer
HCO₃⁻ = 35.9 mmol/L
6.Arterial blood gas interpretation
Answer: added normal-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 = 145 − (113 + 10) = 22
Delta ratio
(22 − 12)/(24 − 10) = 0.7143
added normal-gap acidosis
Answer
added normal-gap acidosis
7.Clinical assessment scores
Answer: MFS = 70
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: yes → 25
secondary diagnosis: yes → 15
ambulatory aid: holds on to furniture → 30
IV therapy or saline lock: no → 0
gait: normal, bed rest or wheelchair → 0
mental status: knows own limits → 0
Add
Morse total = 25 + 15 + 30 + 0 + 0 + 0 = 70
Answer
MFS = 70
8.Clinical assessment scores
Answer: not at risk
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: slightly limited → 3
nutrition: excellent → 4
friction and shear: potential problem → 2
Add
Braden total = 4 + 4 + 2 + 3 + 4 + 2 = 19
Risk level
19 → not at risk
Answer
not at risk
9.Enteral & parenteral nutrition calculations
Answer: %IBW = 135 %
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.
Ideal body weight (Devine)
183 cm/2.54 = 72.05 in
IBW = 45.5 + 2.3·(72.05 − 60) = 73.21 kg
Percentage of ideal body weight
%IBW = 99/73.21·100 = 135.2 ≈ 135%
Answer
%IBW = 135%
10.Enteral & parenteral nutrition calculations
Answer: GIR = 2.28 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 in the bag
15·1000/100 = 150 g = 150 000 mg
Minutes of infusion
18·60 = 1080 min
Glucose infusion rate
GIR = 150 000/(61·1080) = 2.277 ≈ 2.28 mg/kg/min
Answer
GIR = 2.28 mg/kg/min
11.ECG rhythm strip interpretation
Answer: QTc = 0.4 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 = 10 × 0.04 = 0.40 s
RR = 25 × 0.04 = 1.00 s
Bazett’s formula
QTc = 0.40/√1.00 = 0.40/1 = 0.4 s
Answer
QTc = 0.4 s
Within the usual limits (about 0.45 s for men, 0.46 s for women). (400 ms)
12.ECG rhythm strip interpretation
Answer: CPR (non-shockable rhythm)
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 = 17 small boxes, 1500 ÷ 17 ≈ 88 per minute.
2. Rhythm: regular, every R–R is 0.68 s.
3. P waves: upright, one before every QRS, all alike.
4. PR interval: 0.18 s, constant, within 0.12–0.20 s.
5. QRS: 0.08 s, narrow (below 0.12 s).
normal sinus rhythm
What the patient shows
no pulse despite organised electrical activity: pulseless electrical activity (PEA), a non-shockable cardiac arrest rhythm
Answer
CPR (non-shockable rhythm)
Answer
CPR (non-shockable rhythm)
PEA is recognised at the bedside, never from the strip alone. This is exam practice, not clinical guidance.
13.Prioritization & delegation
Answer: A · Dry and warm the baby while checking that it is breathing
Why this is the answer
Breathing and keeping warm come first. Drying stimulates breathing and reduces heat loss; skin-to-skin contact helps. Weighing and routine injections can wait.
Answer
A · Dry and warm the baby while checking that it is breathing
14.Prioritization & delegation
Answer: C · First dose of IV antibiotic for a patient with suspected sepsis
Why this is the answer
Early antibiotics improve survival in sepsis and are ideally given within an hour of recognition. The other tasks are routine and can wait.
Answer
C · First dose of IV antibiotic for a patient with suspected sepsis
15.Infection control & patient safety
Answer: D · Hold the bottle with the label in the palm and pour without touching the bowl
Why this is the answer
The nurse pours from a little height without touching the sterile bowl, avoiding splashes that would wet the field. Holding the label in the palm keeps it readable and free of drips.
Answer
D · Hold the bottle with the label in the palm and pour without touching the bowl
16.Infection control & patient safety
Answer: B · Patient masked, CT warned in advance, staff in respirators
Why this is the answer
Urgent tests are not delayed, but the patient wears a surgical mask to contain particles, the route is planned, and the receiving staff are informed so they can protect themselves and other patients.
Answer
B · Patient masked, CT warned in advance, staff in respirators
17.Lab values & electrolytes
Answer: D · Hold the dose and inform the prescriber
Why this is the answer
A level of 2.8 ng/mL is above the usual range, and the slow heart rate fits toxicity. The nurse holds the dose, checks potassium and the ECG and informs the prescriber.
Answer
D · Hold the dose and inform the prescriber
18.Lab values & electrolytes
Answer: C · A low ionized calcium
Why this is the answer
Stored blood contains citrate, which binds calcium. During massive transfusion, citrate can lower ionized calcium, causing tetany, hypotension and arrhythmias. Ionized calcium is monitored and replaced as prescribed.