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
A dying patient is no longer drinking and breathes through the mouth. What mouth care is most appropriate?
AKeep the mouth and lips moist with frequent gentle care
BClean the mouth only once a day with a hard toothbrush
CAvoid mouth care so the patient is not disturbed
DGive large drinks of water every hour
2.Nursing fundamentalsHard
A nurse escalated a deteriorating patient, but the doctor has not come after 30 minutes and the patient is getting worse. What should the nurse do?
AWait, since the doctor has already been told
BWrite in the notes that the doctor did not come and do nothing else
CEscalate further, for example to a senior doctor or the rapid response team
DTreat the patient with drugs from the cupboard without a prescription
3.Clinical nursingMedium
Under the Mental Capacity Act 2005 (England and Wales), which principle applies?
AA person must be assumed to have capacity unless it is shown that they lack it
BA diagnosis of dementia means the person lacks capacity for all decisions
CEveryone over 75 is assumed to lack capacity
DCapacity is decided by the next of kin, who must sign a form for every decision
4.Clinical nursingHard
A patient on metformin with reduced kidney function is due a CT scan with IV contrast. Why might metformin be withheld?
AMetformin makes the images blurry
BMetformin reacts with the contrast to cause severe hyperglycaemia
CThere is a risk of lactic acidosis if kidney function worsens
DMetformin causes severe bleeding during scans
5.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.38, PaCO₂ 30 mmHg (4.0 kPa) and HCO₃⁻ 17 mmol/L. The primary disorder is metabolic acidosis. How far is it compensated? Click your answer.
pH 7.38PaCO₂ 30 mmHg (4.0 kPa)HCO₃⁻ 17 mmol/L
1uncompensated
2partially compensated
3fully compensated
6.Arterial blood gas interpretationHard
At sea level, a practice gas taken on 24% oxygen shows PaO₂ 71 mmHg (9.5 kPa) and PaCO₂ 29 mmHg (3.9 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.
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: crutches, cane or walker; IV therapy or saline lock: no; gait: impaired; 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). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 14/min, SpO₂ 89% on room air, blood pressure 112/68 mmHg, pulse 58/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). Use the Devine formula to find the ideal body weight IBW of a man who is 182 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 1200 mL of parenteral nutrition with final concentrations of 20% dextrose and 6% amino acids, plus 500 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.
1200 mLdextrose 20%amino acids 6%lipid 500 mL · 1.1 kcal/mL
E = 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 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
1first-degree AV block
2third-degree (complete) AV block
3second-degree AV block type I (Wenckebach)
4second-degree AV block type II
13.Prioritization & delegationMedium
A nurse teaches a patient with heart failure. Which statement shows a need for further teaching?
A“I will take my water tablet in the morning.”
B“I will weigh myself every morning after I use the toilet.”
C“I add extra salt to my food so it tastes better.”
D“I will call if my weight goes up quickly over a day or two.”
14.Prioritization & delegationHard
Two days after starting haloperidol, a patient suddenly develops painful neck twisting and the eyes roll upwards. What should the nurse anticipate?
APhysical restraint until the spasm passes
BNo action, because the spasm is a sign of improvement
CAn anticholinergic drug, such as benztropine or procyclidine, as prescribed
DA higher dose of haloperidol to calm the patient and stop the movements quickly
15.Infection control & patient safetyMedium
Why is blood glucose control important around the time of surgery?
AHigh glucose impairs white cell function and raises the risk of surgical site infection
BLow glucose is needed around surgery so that the wound edges close more quickly
CHigh glucose makes anesthetic drugs work for much longer and delays waking up
DGlucose levels only affect patients who have type 1 diabetes
16.Infection control & patient safetyHard
While preparing a chemotherapy infusion, the drug splashes onto a nurse’s forearm. What should the nurse do first?
AWipe the skin with an alcohol swab and continue preparing the infusion
BFinish hanging the infusion and then wash the skin
CCover the area with a dressing and report later
DRemove contaminated PPE and wash the skin with soap and water at once
17.Lab values & electrolytesMedium
Why can a patient with liver failure have a raised INR without taking warfarin?
AThe liver makes most clotting factors, so production falls
BThe kidneys stop clearing the clotting factors from the blood
CAlbumin is a clotting factor, and its level falls
DBilirubin directly destroys the clotting factors
18.Lab values & electrolytesHard
A patient's creatinine was 0.9 mg/dL (80 µmol/L) on admission and is 1.3 mg/dL (115 µmol/L) 36 hours later. Using the common KDIGO criteria, what does this show?
AAcute kidney injury, because it rose by at least 0.3 mg/dL within 48 hours
BChronic kidney disease, because creatinine has risen above baseline
CA laboratory error, because creatinine cannot change within 2 days
DNo kidney injury, because the creatinine is still within the normal range
3Solutions
1.Nursing fundamentals
Answer: A · Keep the mouth and lips moist with frequent gentle care
Why this is the answer
Frequent gentle mouth care with moist swabs, water sprays and lip balm keeps the patient comfortable. Forcing fluids risks choking and aspiration.
Answer
A · Keep the mouth and lips moist with frequent gentle care
2.Nursing fundamentals
Answer: C · Escalate further, for example to a senior doctor or the rapid response team
Why this is the answer
If a response is delayed and the patient deteriorates, the nurse follows the escalation policy to the next level and keeps monitoring and supporting ABCDE. Each step is documented.
Answer
C · Escalate further, for example to a senior doctor or the rapid response team
3.Clinical nursing
Answer: A · A person must be assumed to have capacity unless it is shown that they lack it
Why this is the answer
The Act begins by presuming capacity. Capacity is decision-specific and time-specific, and people must be given all practicable help to make their own decision.
Answer
A · A person must be assumed to have capacity unless it is shown that they lack it
4.Clinical nursing
Answer: C · There is a risk of lactic acidosis if kidney function worsens
Why this is the answer
Iodinated contrast can worsen kidney function, and metformin can then accumulate and cause lactic acidosis. Local policy guides when to stop and restart it.
Answer
C · There is a risk of lactic acidosis if kidney function worsens
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 30 mmHg: low (35–45)
HCO₃⁻ 17 mmol/L: low (22–26)
Compensation
Clinically, also check the expected compensation: Winter’s formula expects PaCO₂ 31.5–35.5 mmHg, so the measured 30 mmHg points to an additional respiratory alkalosis (a mixed disorder). The answer above is the ROME exam classification.
fully compensated
Answer
fully compensated
6.Arterial blood gas interpretation
Answer: A–a gradient = 63.87 mmHg
Derived values: calculated serum osmolality is 2·Na⁺ + glucose + urea with all values in mmol/L (2·Na⁺ + glucose/18 + BUN/2.8 with glucose and BUN in mg/dL); normal is about 275–295 mOsm/kg. The P/F ratio is PaO₂ divided by FiO₂ as a fraction. The alveolar oxygen pressure is PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 mmHg at sea level, and the A–a gradient is PAO₂ − PaO₂.
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: crutches, cane or walker → 15
IV therapy or saline lock: no → 0
gait: impaired → 20
mental status: knows own limits → 0
Add
Morse total = 25 + 15 + 15 + 0 + 20 + 0 = 75
Answer
MFS = 75
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 14/min → 0
SpO₂ 89% → 3
on air → 0
SBP 112 mmHg → 0
HR 58/min → 0
alert (A) → 0
T 36.8 °C → 0
Total and red scores
NEWS2 = 0 + 3 + 0 + 0 + 0 + 0 + 0 = 3
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: IBW = 76.8 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
182 cm/2.54 = 71.65 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(71.65 − 60) = 76.8 kg
Answer
IBW = 76.8 kg
10.Enteral & parenteral nutrition calculations
Answer: E = 1654 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: 20·1200/100 = 240 g
amino acids: 6·1200/100 = 72 g
Kilocalories per component
dextrose: 240·3.4 = 816 kcal
amino acids: 72·4 = 288 kcal
lipid: 500·1.1 = 550 kcal
Total energy
E = 816 + 288 + 550 = 1654 kcal/day
Answer
E = 1654 kcal/day
11.ECG rhythm strip interpretation
Answer: QTc = 0.424 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 = 9 × 0.04 = 0.36 s
RR = 18 × 0.04 = 0.72 s
Bazett’s formula
QTc = 0.36/√0.72 = 0.36/0.8485 = 0.424 s
Answer
QTc = 0.424 s
Within the usual limits (about 0.45 s for men, 0.46 s for women). (424 ms)
12.ECG rhythm strip interpretation
Answer: second-degree AV block type I (Wenckebach)
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: regularly irregular, the QRS complexes come in groups separated by a pause (group beating).
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: lengthens 0.16 → 0.30 s, then a P wave is not conducted.
5. QRS: 0.08 s, narrow (below 0.12 s).
Interpretation
second-degree AV block type I (Wenckebach)
Answer
second-degree AV block type I (Wenckebach)
13.Prioritization & delegation
Answer: C · “I add extra salt to my food so it tastes better.”
Why this is the answer
Salt causes fluid retention and can worsen heart failure. Daily weights, reporting rapid weight gain and taking diuretics in the morning are all correct.
Answer
C · “I add extra salt to my food so it tastes better.”
14.Prioritization & delegation
Answer: C · An anticholinergic drug, such as benztropine or procyclidine, as prescribed
Why this is the answer
Acute dystonia is an early extrapyramidal effect of antipsychotics. It responds quickly to an anticholinergic drug; it can be frightening, and laryngeal spasm can threaten the airway.
Answer
C · An anticholinergic drug, such as benztropine or procyclidine, as prescribed
15.Infection control & patient safety
Answer: A · High glucose impairs white cell function and raises the risk of surgical site infection
Why this is the answer
Hyperglycemia weakens neutrophil function and slows healing, so it increases the risk of surgical site infection. Keeping glucose in the target range is part of infection prevention for surgical patients.
Answer
A · High glucose impairs white cell function and raises the risk of surgical site infection
16.Infection control & patient safety
Answer: D · Remove contaminated PPE and wash the skin with soap and water at once
Why this is the answer
Skin exposure to hazardous drugs is washed immediately with soap and water after removing contaminated gloves or gown. The exposure is then reported and treated according to policy.
Answer
D · Remove contaminated PPE and wash the skin with soap and water at once
17.Lab values & electrolytes
Answer: A · The liver makes most clotting factors, so production falls
Why this is the answer
The liver makes most clotting factors, including the vitamin K–dependent ones. In severe liver disease their production falls, so the INR rises. A raised INR is one of the markers of how severe liver failure is.Checked against:Prothrombin Time Test and INR (PT/INR) · MedlinePlus (NIH) (2024)
Answer
A · The liver makes most clotting factors, so production falls
18.Lab values & electrolytes
Answer: A · Acute kidney injury, because it rose by at least 0.3 mg/dL within 48 hours
Why this is the answer
KDIGO defines AKI as a creatinine rise of at least 0.3 mg/dL (26.5 µmol/L) within 48 hours, a rise to 1.5 times baseline within 7 days, or urine output below 0.5 mL/kg/h for 6 hours. A result inside the reference range can still be a significant rise.
Answer
A · Acute kidney injury, because it rose by at least 0.3 mg/dL within 48 hours