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
Which measures help prevent constipation in hospital patients?
ALimiting fluids and staying in bed to rest the bowel
BHolding in the urge to open the bowels
CAvoiding fruit and vegetables
DAdequate fluids, dietary fibre and mobility
2.Nursing fundamentalsHard
While counting an apical pulse, the nurse finds the rhythm is irregularly irregular and the radial rate is lower than the apical rate. Which rhythm is most likely?
ASinus bradycardia
BAtrial fibrillation
CSinus tachycardia
DNormal sinus rhythm
3.Clinical nursingMedium
Why must a patient with a new coronary stent not stop their antiplatelet medicines without specialist advice?
AStopping early greatly increases the risk of a clot forming in the stent
BStopping causes severe low blood pressure
CStopping causes immediate kidney failure
DThe stent will dissolve if the drugs are stopped before the course ends
4.Clinical nursingHard
Which ECG change is classically associated with severe hyperkalaemia?
AA shortened PR interval
BST depression only
CProminent U waves
DTall, peaked T waves
5.Arterial blood gas interpretationMedium
A practice gas shows a metabolic acidosis with HCO₃⁻ 12 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.
HCO₃⁻ 12 mmol/L
PaCO₂ = mmHg
6.Arterial blood gas interpretationHard
At sea level, a practice gas taken on 21% oxygen shows PaO₂ 58 mmHg (7.7 kPa) and PaCO₂ 53 mmHg (7.1 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 after a head injury opens the eyes only to pressure (a painful stimulus), says inappropriate, random words and shows as the best motor response: withdraws the limb from pressure (normal flexion). Work out the GCS and classify the head injury by it. Click your answer.
1mild
2moderate
3severe
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 99% on room air, blood pressure 112/68 mmHg, pulse 88/min, alert, temperature 36.1 °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 189 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 1500 mL of parenteral nutrition with final concentrations of 15% dextrose and 4.25% 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 15%amino acids 4.25%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 second-degree AV block type I (Wenckebach). Measure the PR interval of the last conducted beat before a non-conducted P wave (the longest PR), in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
longest PR = s
13.Prioritization & delegationMedium
A nurse finds a patient on the floor next to the bed. What is the first action?
AHelp the patient straight back into bed with the help of a colleague
BCall the patient’s family to explain what happened
CAssess the patient for responsiveness and injury before moving them
DComplete an incident report while the details are fresh
14.Prioritization & delegationHard
A patient after major surgery has a urine output of 15 mL/h for two hours, a heart rate of 115/min and cool hands. What should the nurse do first?
AFlush the catheter and recheck the output tomorrow morning
BEncourage the patient to drink more water and recheck later
CWait another two hours to see whether the output improves
DAssess for signs of shock, such as bleeding, and escalate
15.Infection control & patient safetyMedium
A nurse receives a needlestick injury from a patient known to have HIV. Why is it important to report it immediately?
AReporting is only needed if the wound bleeds or is deep
BReporting is only needed for injuries from IV needles
CReporting can be done at any time within a month without changing the risk
DPost-exposure prophylaxis works best when started within hours
16.Infection control & patient safetyHard
The laboratory reports that a blood sample labeled with one patient’s name has a blood group different from that patient’s previous result. What is the most likely problem and response?
AA normal change in the patient’s blood group over the years since the last test
BThe previous result was wrong, so it is deleted
CA wrong-patient sample, so the test is repeated and the event reported
DA laboratory machine fault, so no action is needed
17.Lab values & electrolytesMedium
A patient starts high-dose prednisone. Which laboratory change should the nurse expect?
AA fall in serum sodium
BA rise in serum potassium
CA rise in blood glucose
DA fall in the white cell count
18.Lab values & electrolytesHard
A patient on clozapine for 2 years has been stable. Which statement shows a need for further teaching?
A"I can stop my blood tests since I feel well"
B"I'll keep all my scheduled blood test visits"
C"I'll tell other doctors that I take clozapine"
D"I'll report a sore throat or fever at once"
3Solutions
1.Nursing fundamentals
Answer: D · Adequate fluids, dietary fibre and mobility
Why this is the answer
Fluids and fibre soften stools, and activity stimulates gut movement. Privacy and responding to the urge to defecate also help. Opioids and immobility increase the risk.
Answer
D · Adequate fluids, dietary fibre and mobility
2.Nursing fundamentals
Answer: B · Atrial fibrillation
Why this is the answer
Atrial fibrillation gives an irregularly irregular pulse, and some beats are too weak to be felt at the wrist, causing a pulse deficit. It should be reported and confirmed with an ECG.
Answer
B · Atrial fibrillation
3.Clinical nursing
Answer: A · Stopping early greatly increases the risk of a clot forming in the stent
Why this is the answer
Dual antiplatelet therapy prevents stent thrombosis while the stent becomes covered by the artery lining. Stopping early can cause a sudden myocardial infarction.
Answer
A · Stopping early greatly increases the risk of a clot forming in the stent
4.Clinical nursing
Answer: D · Tall, peaked T waves
Why this is the answer
Hyperkalaemia causes peaked T waves, then a widened QRS and possibly a sine-wave pattern and arrest. Hypokalaemia causes flat T waves and U waves.
Answer
D · Tall, peaked T waves
5.Arterial blood gas interpretation
Answer: PaCO₂ = 26 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 = 1.5·12 + 8 = 26 mmHg
range: 24–28 mmHg
Answer
PaCO₂ = 26 mmHg
6.Arterial blood gas interpretation
Answer: A–a gradient = 25.48 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.
Glasgow Coma Scale: add the best response in three areas. Eye opening E: 4 spontaneous, 3 to sound or speech, 2 to pressure, 1 none. Verbal V: 5 oriented, 4 confused, 3 inappropriate words, 2 incomprehensible sounds, 1 none. Motor M: 6 obeys commands, 5 localises, 4 normal flexion (withdraws), 3 abnormal flexion, 2 extension, 1 none. The total runs from 3 to 15. After a head injury, 13–15 is usually called mild, 9–12 moderate and 3–8 severe.
Score each area
E: opens the eyes only to pressure (a painful stimulus) → 2
V: says inappropriate, random words → 3
M: withdraws the limb from pressure (normal flexion) → 4
Add
GCS = 2 + 3 + 4 = 9
Severity
GCS 9 → moderate
Answer
moderate
8.Clinical assessment scores
Answer: low
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 99% → 0
on air → 0
SBP 112 mmHg → 0
HR 88/min → 0
alert (A) → 0
T 36.1 °C → 0
Total and red scores
NEWS2 = 0 + 0 + 0 + 0 + 0 + 0 + 0 = 0
No parameter scores 3.
Risk group
low
Answer
low
9.Enteral & parenteral nutrition calculations
Answer: IBW = 83.1 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
189 cm/2.54 = 74.41 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(74.41 − 60) = 83.14 ≈ 83.1 kg
Answer
IBW = 83.1 kg
10.Enteral & parenteral nutrition calculations
Answer: NPC = 1265 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: 15·1500/100 = 225 g
amino acids: 4.25·1500/100 = 63.75 g
Kilocalories per component
dextrose: 225·3.4 = 765 kcal
amino acids: 63.75·4 = 255 kcal
lipid: 250·2 = 500 kcal
Non-protein energy
NPC = 765 + 500 = 1265 kcal/day
Answer
NPC = 1265 kcal/day
11.ECG rhythm strip interpretation
Answer: pause = 2.16 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
54 small boxes from R to R across the pause
Convert
pause = 54 × 0.04 s = 2.16 s
Compare with P–P
2.16 ÷ 0.96 ≈ 2.3 P–P cycles, not a whole number
Answer
pause = 2.16 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:longest PR = 0.36 s
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.
March out the P waves
P–P = 0.92 s, regular; one P wave in every 4 is not conducted
PR in each group
PR₁ = 0.18 s, PR₂ = 0.30 s, PR₃ = 0.36 s
Answer
longest PR = 0.36 s
The biggest step in PR comes between the first and second beats of a group; later steps are smaller, which is why the R–R intervals shorten before the pause.
13.Prioritization & delegation
Answer: C · Assess the patient for responsiveness and injury before moving them
Why this is the answer
The nurse first checks responsiveness, breathing and injuries such as head trauma or a hip fracture. Only then is the patient moved safely, with help. The provider is informed, and the report is completed afterwards.
Answer
C · Assess the patient for responsiveness and injury before moving them
14.Prioritization & delegation
Answer: D · Assess for signs of shock, such as bleeding, and escalate
Why this is the answer
These signs together suggest hypovolemia or shock. The nurse assesses the whole patient, looks for bleeding and escalates. A catheter problem should be ruled out, but it should not delay recognition of shock.
Answer
D · Assess for signs of shock, such as bleeding, and escalate
15.Infection control & patient safety
Answer: D · Post-exposure prophylaxis works best when started within hours
Why this is the answer
After washing the wound with soap and water, the nurse reports at once so the exposure can be assessed. HIV post-exposure prophylaxis should start as soon as possible, ideally within hours and no later than 72 hours.
Answer
D · Post-exposure prophylaxis works best when started within hours
16.Infection control & patient safety
Answer: C · A wrong-patient sample, so the test is repeated and the event reported
Why this is the answer
A different blood group strongly suggests the sample came from another patient. A new sample is taken with careful bedside identification and labeling, and the event is reported as a serious near miss.
Answer
C · A wrong-patient sample, so the test is repeated and the event reported
17.Lab values & electrolytes
Answer: C · A rise in blood glucose
Why this is the answer
Glucocorticoids raise blood glucose by increasing glucose production and reducing insulin sensitivity. They also tend to lower potassium, retain sodium and raise the white cell count by releasing neutrophils into the blood.Checked against:Blood Glucose Test · MedlinePlus (NIH) (2024)
Answer
C · A rise in blood glucose
18.Lab values & electrolytes
Answer: A · "I can stop my blood tests since I feel well"
Why this is the answer
Clozapine requires ongoing ANC monitoring according to the schedule, because severe neutropenia can occur without warning. The patient must keep blood test appointments and report signs of infection at once.