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
If hair needs to be removed before surgery, what is recommended?
AShaving with a razor the night before
BPlucking the hairs with tweezers
CHair removal cream applied in theatre
DElectric clippers on the day of surgery
2.Nursing fundamentalsHard
A nurse has a needlestick injury from a used needle. What is the correct first action?
AScrub the area hard with a brush and alcohol, then report it at the end of the shift
BLet it bleed freely, wash with soap and running water, then report it urgently
CFinish the shift and report it the next day
DSuck the wound to remove the blood
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 make the procedure faster
CBecause the remaining sutures dissolve on their own within a day
DTo reduce the cost of dressings
4.Clinical nursingHard
Why must blood samples for a cross-match be labelled at the bedside immediately after they are taken?
ATo keep the sample warm so the cells do not break down in transit
BTo speed up the laboratory's computer system and reduce the waiting time
CTo let the patient sign the label
DTo prevent "wrong blood in tube" errors that can cause fatal reactions
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 152 mmol/L, glucose 18.1 mmol/L and urea 11.8 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 152 mmol/Lglucose 18.1 mmol/Lurea 11.8 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
Practice values: Na⁺ 139, Cl⁻ 110, HCO₃⁻ 10 mmol/L and albumin 30 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 16/min, SpO₂ 92% on room air, blood pressure 136/82 mmHg, pulse 88/min, alert, temperature 39.0 °C. What is the NEWS2 total score?
RR 16SpO₂ 92%airSBP 136HR 88AT 39.0 °C
NEWS2 =
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 92% on supplemental oxygen, blood pressure 150/90 mmHg, pulse 132/min, unresponsive, temperature 34.8 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). A 65 kg patient has a fluid goal of 35 mL/kg/day and receives all fluid through a feeding tube. The formula is 84% free water and runs at 65 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). Over 24 hours a patient receives 1500 mL of parenteral nutrition with final concentrations of 10% dextrose and 6% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
1500 mLdextrose 10%amino acids 6%lipid 250 mL · 2 kcal/mL
NPC = kcal/day
11.ECG rhythm strip interpretationMedium
This lead II strip shows sinus rhythm with one pause. Measure the pause, the R–R interval across it, in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
pause = s
12.ECG rhythm strip interpretationHard
This lead II strip shows an AV block, so the atria and the ventricles beat at different rates. Measure the P–P interval and find the atrial rate in beats per minute (1500 method, whole number).
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
13.Prioritization & delegationMedium
Which nursing assistant task is appropriate for a patient two days after hip replacement?
AHelping the patient into a chair, following the hip precautions
BChecking the incision for redness, warmth and drainage
CEvaluating whether the last dose of pain medication controlled the pain
DTeaching the patient the hip precautions before discharge
14.Prioritization & delegationHard
During a continuous tube feed, a patient suddenly starts coughing, becomes breathless and the SpO₂ falls. What is the nurse’s first action?
ALie the patient flat so they can rest
BIncrease the feed rate so that it finishes sooner
CFlush the tube with 50 mL of water, then continue the feed as before
DStop the feed, sit the patient upright and assess breathing
15.Infection control & patient safetyMedium
Why are independent double checks used for some medicines, such as insulin and heparin infusions?
ATo make the preparation process faster
BTo share responsibility between two nurses if an error happens
CBecause these drugs are very expensive to waste
DA second person checking separately catches missed errors
16.Infection control & patient safetyHard
A woman in late pregnancy is choking and cannot speak or cough. Which technique should the rescuer use?
AAbdominal thrusts
BBack blows only
CBlind finger sweeps
DChest thrusts
17.Lab values & electrolytesMedium
A patient with hyperkalemia received IV regular insulin with dextrose. Which result must the nurse monitor closely over the next hours?
ASerum calcium, because it falls sharply
BSerum sodium, because it rises quickly
CBlood glucose, because hypoglycemia can occur
DHemoglobin, because insulin causes red cell loss
18.Lab values & electrolytesHard
A patient in hyperosmolar hyperglycemic state has a glucose of 1,050 mg/dL (58 mmol/L), very dry mucous membranes and a fast pulse. Which treatment is usually the first priority?
ALarge-volume IV fluid replacement
BOral glucose-lowering tablets
CStrict fluid restriction
DAn IV bolus of sodium bicarbonate
3Solutions
1.Nursing fundamentals
Answer: D · Electric clippers on the day of surgery
Why this is the answer
Razors cause small skin cuts that increase surgical site infection. If needed, hair is removed with electric clippers close to the time of surgery.
Answer
D · Electric clippers on the day of surgery
2.Nursing fundamentals
Answer: B · Let it bleed freely, wash with soap and running water, then report it urgently
Why this is the answer
First aid is to let the wound bleed freely without squeezing, wash it with soap and running water and cover it, without scrubbing or sucking. Reporting straight away allows a risk assessment and, if needed, post-exposure prophylaxis.
Answer
B · Let it bleed freely, wash with soap and running water, then report it urgently
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: D · To prevent "wrong blood in tube" errors that can cause fatal reactions
Why this is the answer
A sample labelled with the wrong patient's details can lead to incompatible blood being issued. Labelling at the bedside after positive identification is a key transfusion safety step.
Answer
D · To prevent "wrong blood in tube" errors that can cause fatal reactions
5.Arterial blood gas interpretation
Answer: Osm = 334 mOsm/kg
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.
Calculated osmolality
Osm = 2·152 + 18.1 + 11.8 = 333.9 ≈ 334 mOsm/kg
Answer
Osm = 334 mOsm/kg
6.Arterial blood gas interpretation
Answer: AGc = 21.5 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.
Anion gap
AG = 139 − (110 + 10) = 19
Correction for albumin
19 + 0.25·(40 − 30) = 21.5 mmol/L
Answer
AGc = 21.5 mmol/L
Above about 12 after correction: a high anion gap.
7.Clinical assessment scores
Answer: NEWS2 = 3
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 16/min → 0
SpO₂ 92% → 2
on air → 0
SBP 136 mmHg → 0
HR 88/min → 0
alert (A) → 0
T 39.0 °C → 1
Add
NEWS2 = 0 + 2 + 0 + 0 + 0 + 0 + 1 = 3
Answer
NEWS2 = 3
8.Clinical assessment scores
Answer: high
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 92% → 2
on oxygen → 2
SBP 150 mmHg → 0
HR 132/min → 3
unresponsive (U) → 3
T 34.8 °C → 3
Total and red scores
NEWS2 = 0 + 2 + 2 + 0 + 3 + 3 + 3 = 13
At least one parameter scores 3.
Risk group
high
Answer
high
A total of 5 or more calls for an urgent clinical response.
9.Enteral & parenteral nutrition calculations
Answer: V = 161 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
35·65 = 2275 mL/day
Free water from the formula
65·24 = 1560 mL
1560·0.84 = 1310 mL
Water still needed
2275 − 1310 = 964.6 mL/day
Volume per flush
24/4 = 6 flushes
V = 964.6/6 = 160.8 ≈ 161 mL
Answer
V = 161 mL
10.Enteral & parenteral nutrition calculations
Answer: NPC = 1010 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: 6·1500/100 = 90 g
Kilocalories per component
dextrose: 150·3.4 = 510 kcal
amino acids: 90·4 = 360 kcal
lipid: 250·2 = 500 kcal
Non-protein energy
NPC = 510 + 500 = 1010 kcal/day
Answer
NPC = 1010 kcal/day
11.ECG rhythm strip interpretation
Answer: pause = 1.64 s
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).
Measure
41 small boxes from R to R across the pause
Convert
pause = 41 × 0.04 s = 1.64 s
Compare with P–P
1.64 ÷ 0.96 ≈ 1.7 P–P cycles, not a whole number
Answer
pause = 1.64 s
No P wave appears in the pause, and the pause is not a whole number of P–P cycles: sinus arrest. A pause of exactly two or three cycles would point to sinus exit block.
12.ECG rhythm strip interpretation
Answer: atrial rate = 71 bpm
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.
Atrial rate
P–P = 21 small boxes = 0.84 s → 1500 ÷ 21 = 71.43 ≈ 71 per minute
Ventricular rate
R–R = 28 small boxes = 1.12 s → 1500 ÷ 28 = 53.57 ≈ 54 per minute
Answer
atrial rate = 71 bpm
Answer
atrial rate = 71 bpm
Third-degree block with a narrow-complex junctional escape (usually 40–60 per minute).
13.Prioritization & delegation
Answer: A · Helping the patient into a chair, following the hip precautions
Why this is the answer
Helping a stable patient move, using precautions already set in the care plan, is a routine task. Inspecting the wound, teaching and evaluating pain relief need nursing assessment.
Answer
A · Helping the patient into a chair, following the hip precautions
14.Prioritization & delegation
Answer: D · Stop the feed, sit the patient upright and assess breathing
Why this is the answer
Coughing, breathlessness and a falling saturation during tube feeding suggest aspiration or a displaced tube. The feed is stopped at once, the patient is sat upright, the airway and breathing are assessed, suction and oxygen are used as needed and the provider is informed. Tube position is checked before any feed restarts.
Answer
D · Stop the feed, sit the patient upright and assess breathing
15.Infection control & patient safety
Answer: D · A second person checking separately catches missed errors
Why this is the answer
In an independent double check, a second qualified person checks the order, the drug, the dose, the calculation and the pump settings on their own. This catches errors that could cause serious harm with high-alert medications.
Answer
D · A second person checking separately catches missed errors
16.Infection control & patient safety
Answer: D · Chest thrusts
Why this is the answer
For people in late pregnancy or who are very obese, chest thrusts replace abdominal thrusts because the rescuer cannot get around the abdomen effectively. Blind finger sweeps can push the object deeper.
Answer
D · Chest thrusts
17.Lab values & electrolytes
Answer: C · Blood glucose, because hypoglycemia can occur
Why this is the answer
Insulin shifts potassium into cells but also lowers glucose, and hypoglycemia can occur hours later, especially in kidney failure. Glucose is checked frequently, and potassium is rechecked, as the effect lasts only a few hours.Checked against:High potassium level · MedlinePlus (NIH) (2025)
Answer
C · Blood glucose, because hypoglycemia can occur
18.Lab values & electrolytes
Answer: A · Large-volume IV fluid replacement
Why this is the answer
In HHS the fluid deficit is often very large, so IV fluid replacement is the first priority; it also lowers the glucose. Insulin follows as prescribed, and potassium, sodium and mental status are monitored closely.Checked against:Diabetic hyperglycemic hyperosmolar syndrome · MedlinePlus (NIH) (2026)