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
At what angle is an intramuscular injection given?
A30 degrees
B15 degrees
C45 degrees
D90 degrees
2.Nursing fundamentalsHard
Why can a patient with a high fever be in negative fluid balance even when measured intake equals measured output?
AFever increases unmeasured fluid loss through sweating and breathing
BFever causes the body to make extra water from fat
CFever has no effect on the body's water balance
DFever makes the kidneys produce extra urine that cannot be measured
3.Clinical nursingMedium
Which drug is first-line in an acute asthma attack?
AAn oral beta-blocker
BAn oral antihistamine such as cetirizine taken every few hours
CA long-acting inhaled corticosteroid, used alone at a higher dose
DA nebulised or inhaled short-acting beta2-agonist (salbutamol/albuterol)
4.Clinical nursingHard
Why must severe chronic hyponatraemia be corrected slowly?
AFast correction makes the kidneys stop producing urine
BToo-rapid correction can cause osmotic demyelination in the brain
CFast correction causes severe hypoglycaemia and seizures in most patients
DSodium given quickly causes immediate cardiac arrest
5.Arterial blood gas interpretationMedium
A practice gas shows a metabolic acidosis with HCO₃⁻ 10 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.
HCO₃⁻ 10 mmol/L
PaCO₂ = mmHg
6.Arterial blood gas interpretationHard
At sea level, a practice gas taken on 30% oxygen shows PaO₂ 86 mmHg (11.5 kPa) and PaCO₂ 33 mmHg (4.4 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 18/min, SpO₂ 99% on room air, blood pressure 124/74 mmHg, pulse 58/min, alert, temperature 38.1 °C. What is the NEWS2 total score?
RR 18SpO₂ 99%airSBP 124HR 58AT 38.1 °C
NEWS2 =
8.Clinical assessment scoresHard
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: normal, bed rest or wheelchair; mental status: overestimates or forgets limits. Using the cut-offs 0–24 low, 25–44 moderate and 45 or more high, click the fall-risk level.
Practice exercise (made-up values, not clinical guidance). A 53 kg patient needs 2 g of protein per kg a day. The tube feed contains 40 g of protein per litre and runs at 75 mL/h for 16 hours a day. A protein powder supplies 7 g of protein per scoop. How many scoops n a day are needed to cover the shortfall? Round up to a whole scoop.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1200 mL of parenteral nutrition with final concentrations of 15% dextrose and 4.25% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the non-protein kilocalorie to nitrogen ratio NPC : N (the number x in x : 1). Round to the nearest whole number.
1200 mLdextrose 15%amino acids 4.25%lipid 250 mL · 1.1 kcal/mL
NPC : N =
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
Interpret this lead II strip with the five steps in order: rate, rhythm, P waves, PR interval, QRS duration. At which step do you find the first abnormal finding? Click it.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
1rate
2rhythm
3P waves
4PR interval
5QRS duration
13.Prioritization & delegationMedium
An anxious patient is breathing very fast and has tingling fingers. The blood gas shows pH 7.51 and PaCO₂ 29 mmHg (3.9 kPa). What should the nurse do first?
AGive oxygen at the highest flow and leave the room
BEncourage the patient to breathe even faster
CGive IV sodium bicarbonate as soon as it can be found
DStay with the patient and coach slow, calm breathing
14.Prioritization & delegationHard
A nursing assistant measured vital signs 15 minutes after a patient’s first dose of morphine. They report a respiratory rate of 10/min and say the patient is hard to wake. What should the nurse do?
AGo at once, rouse the patient, support breathing and prepare naloxone per order
BDocument the findings and tell the provider at the next scheduled round
CAsk the assistant to recheck the respiratory rate in 15 minutes and report back
DPhone the provider for orders before going to see the patient
15.Infection control & patient safetyMedium
A nurse is preparing medications for two patients. What is the safest approach?
APut both patients’ medications in one cup and sort them at the bedside
BPrepare and give medications for one patient at a time
CPrepare both patients’ medications together to save time
DAsk one patient to pass the medications to the other
16.Infection control & patient safetyHard
A newly hired nurse has these hepatitis B results: HBsAg negative, anti-HBs positive, anti-HBc negative. What do they show?
AImmunity from hepatitis B vaccination
BNo immunity, so the vaccine is needed
CA current hepatitis B infection
DPast infection that has now cleared
17.Lab values & electrolytesMedium
A patient takes valproate (valproic acid) for epilepsy. Which tests are monitored regularly?
ASerum lithium and urine specific gravity
BThyroid function and serum calcium
CLiver function tests and platelet count
DTroponin and B-type natriuretic peptide
18.Lab values & electrolytesHard
A patient with sepsis has the following new results. Which set best shows organ dysfunction?
DWBC 11.5 × 10³/µL, potassium 4.2 mEq/L, albumin 3.8 g/dL
3Solutions
1.Nursing fundamentals
Answer: D · 90 degrees
Why this is the answer
Intramuscular injections are given at 90 degrees so the needle passes through the skin and fat into the muscle. Intradermal injections use about 10–15 degrees.
Answer
D · 90 degrees
2.Nursing fundamentals
Answer: A · Fever increases unmeasured fluid loss through sweating and breathing
Why this is the answer
Insensible losses through the skin and lungs are not measured and rise with fever and fast breathing. A balanced chart can therefore hide a real fluid deficit.
Answer
A · Fever increases unmeasured fluid loss through sweating and breathing
3.Clinical nursing
Answer: D · A nebulised or inhaled short-acting beta2-agonist (salbutamol/albuterol)
Why this is the answer
Short-acting beta2-agonists relieve bronchospasm within minutes. Oxygen to target, steroids and other treatments are added according to severity.
Answer
D · A nebulised or inhaled short-acting beta2-agonist (salbutamol/albuterol)
4.Clinical nursing
Answer: B · Too-rapid correction can cause osmotic demyelination in the brain
Why this is the answer
In chronic hyponatraemia brain cells adapt to the low tonicity. A rapid rise in sodium draws water out too fast and can cause osmotic demyelination, so the correction rate is limited and sodium is checked often.
Answer
B · Too-rapid correction can cause osmotic demyelination in the brain
5.Arterial blood gas interpretation
Answer: PaCO₂ = 23 mmHg
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.
Winter’s formula
PaCO₂ = 1.5·10 + 8 = 23 mmHg
range: 21–25 mmHg
Answer
PaCO₂ = 23 mmHg
6.Arterial blood gas interpretation
Answer: A–a gradient = 86.65 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.
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 18/min → 0
SpO₂ 99% → 0
on air → 0
SBP 124 mmHg → 0
HR 58/min → 0
alert (A) → 0
T 38.1 °C → 1
Add
NEWS2 = 0 + 0 + 0 + 0 + 0 + 0 + 1 = 1
Answer
NEWS2 = 1
8.Clinical assessment scores
Answer: moderate risk
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: normal, bed rest or wheelchair → 0
mental status: overestimates or forgets limits → 15
Add
Morse total = 0 + 0 + 0 + 20 + 0 + 15 = 35
Risk level
35 → moderate risk
Answer
moderate risk
9.Enteral & parenteral nutrition calculations
Answer: n = 9
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.
Protein needed
2·53 = 106 g/day
Protein from the feed
75·16 = 1200 mL = 1.2 L
1.2·40 = 48 g/day
Shortfall
ΔP = 106 − 48 = 58 g
Scoops
58/7 = 8.286 → n = 9
Answer
n = 9
10.Enteral & parenteral nutrition calculations
Answer: NPC : N = 109
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: 15·1200/100 = 180 g
amino acids: 4.25·1200/100 = 51 g
Kilocalories per component
dextrose: 180·3.4 = 612 kcal
amino acids: 51·4 = 204 kcal
lipid: 250·1.1 = 275 kcal
Non-protein kcal and nitrogen
NPC = 612 + 275 = 887 kcal
N = 51/6.25 = 8.16 g
Ratio
NPC : N = 887/8.16 = 108.7 ≈ 109 : 1
Answer
NPC : N = 109
Ratios of about 150 : 1 are typical for stable patients; lower ratios give relatively more protein.
11.ECG rhythm strip interpretation
Answer: QTc = 0.465 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 = 15 × 0.04 = 0.60 s
Bazett’s formula
QTc = 0.36/√0.60 = 0.36/0.7746 = 0.465 s
Answer
QTc = 0.465 s
Above the usual limits for both men (about 0.45 s) and women (about 0.46 s): prolonged. (465 ms)
12.ECG rhythm strip interpretation
Answer: rate
Five steps for every strip: 1. rate (300 or 1500 method, or the 6-second method if irregular); 2. rhythm: are the R–R intervals equal; 3. P waves: present, upright in lead II, one before every QRS and all alike; 4. PR interval: 0.12–0.20 s and constant; 5. QRS duration: below 0.12 s. Only after the five steps name the rhythm. Normal sinus rhythm passes all five: 60–100/min, regular, upright P before every QRS, PR 0.12–0.20 s, QRS below 0.12 s.
Five steps
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).
First abnormal step
rate → sinus tachycardia
Answer
rate
13.Prioritization & delegation
Answer: D · Stay with the patient and coach slow, calm breathing
Why this is the answer
These results show respiratory alkalosis caused by hyperventilation. Calming the patient and coaching slower breathing lets carbon dioxide return to normal; the nurse also looks for physical causes.
Answer
D · Stay with the patient and coach slow, calm breathing
14.Prioritization & delegation
Answer: A · Go at once, rouse the patient, support breathing and prepare naloxone per order
Why this is the answer
Slow breathing and difficulty rousing suggest opioid-induced respiratory depression. The nurse assesses the patient straight away, stimulates them, supports breathing, gives naloxone per order and escalates. Waiting or calling without seeing the patient wastes critical minutes.
Answer
A · Go at once, rouse the patient, support breathing and prepare naloxone per order
15.Infection control & patient safety
Answer: B · Prepare and give medications for one patient at a time
Why this is the answer
Preparing, checking and giving medications for one patient at a time, at the bedside, reduces wrong-patient errors. Mixing medicines makes errors more likely.
Answer
B · Prepare and give medications for one patient at a time
16.Infection control & patient safety
Answer: A · Immunity from hepatitis B vaccination
Why this is the answer
The vaccine contains surface antigen, so it produces anti-HBs only. A negative anti-HBc shows there has been no natural infection, and a negative HBsAg rules out current infection.
Answer
A · Immunity from hepatitis B vaccination
17.Lab values & electrolytes
Answer: C · Liver function tests and platelet count
Why this is the answer
Valproate can cause liver toxicity and thrombocytopenia, so liver tests and the platelet count are monitored. It can also raise ammonia; confusion or vomiting should prompt an ammonia level.Checked against:Valproic Acid · StatPearls (NCBI Bookshelf) (2024)
In sepsis, falling platelets (coagulation), a rising creatinine (kidney) and a raised bilirubin (liver) show organ dysfunction, which indicates severe disease. The other sets are normal or near normal.Checked against:Bacterial Sepsis · StatPearls (NCBI Bookshelf) (2023); Laboratory Evaluation of Sepsis · StatPearls (NCBI Bookshelf) (2023)
Answer
A · Platelets 70 × 10³/µL, creatinine doubled, bilirubin raised