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
Why should a patient wash and dry their hands before a fingerprick glucose test?
AClean hands make the finger bleed more slowly
BIt is only needed if the hands look dirty
CSugar on the skin can give a falsely high reading
DWet hands give a falsely high reading
2.Nursing fundamentalsHard
The daughter of a dying patient is upset that her mother has stopped eating. What is the best response?
AExplain that losing appetite is a natural part of dying
BTell her it means the staff have not been feeding her mother
CEncourage her to help her mother eat a full meal at every mealtime
DTell her a feeding tube will be inserted straight away
3.Clinical nursingMedium
A patient says they are "allergic" to codeine because it made them constipated. How should this be recorded?
AIt should not be recorded at all
BAs a severe anaphylactic allergy to all opioids
CAs a side effect or intolerance, not a true allergy
DAs an allergy to all painkillers
4.Clinical nursingHard
Which set of findings best distinguishes cardiogenic shock from hypovolaemic shock?
ATachycardia, hypotension and a weak, thready peripheral pulse
BReduced urine output
CCool, pale skin
DRaised jugular venous pressure and lung crackles
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 150 mmol/L, glucose 27.8 mmol/L and urea 4.3 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 150 mmol/Lglucose 27.8 mmol/Lurea 4.3 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
Practice values: Na⁺ 136, Cl⁻ 102, HCO₃⁻ 14 mmol/L and albumin 26 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).
Practice exercise (made-up values, not clinical guidance). A practice chart records GCS 11, with E3 and V4. What motor score M was recorded, and which response does it describe? Give the number.
GCS 11E3V4
M =
8.Clinical assessment scoresHard
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 supplemental oxygen, blood pressure 130/78 mmHg, pulse 50/min, newly confused, temperature 36.9 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). A 61 kg adult (BMI below 30) needs 25 kcal/kg/day. The tube feed provides 1 kcal/mL and runs by pump for 16 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1200 mL of parenteral nutrition with final concentrations of 25% dextrose and 4.25% 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 25%amino acids 4.25%lipid 500 mL · 1.1 kcal/mL
E = 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
Identify the rhythm on this lead II strip. 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
1ventricular tachycardia
2atrial fibrillation
3ventricular fibrillation
4torsades de pointes
13.Prioritization & delegationMedium
A nurse takes a telephone order from a provider. What must the nurse do?
AWrite the order down and read it back to the provider to confirm it
BAsk the ward clerk to take the order on the nurse’s behalf instead
CCarry out the order first and ask the provider to confirm it later
DRemember the order and write it in the chart at the end of the shift
14.Prioritization & delegationHard
A patient with major depression has been withdrawn for weeks but is suddenly calm and cheerful and gives away her belongings. What should the nurse suspect?
AA raised risk of suicide, because she may have made a decision
BThat she is getting ready for discharge as planned
CA full recovery, so observation can be reduced
DA side effect of her antidepressant medicine that needs no special action
15.Infection control & patient safetyMedium
A small spill of blood is found on the floor. How should it be cleaned?
AWipe it up quickly with a dry cloth using bare hands, then wash the hands well
BWear gloves, absorb the blood, then clean the area with an approved disinfectant
CLeave it until housekeeping arrives the next morning
DCover it with a clean sheet and keep working
16.Infection control & patient safetyHard
A nurse picks up a heparin vial that contains 10 000 units/mL; the ward usually stocks 1000 units/mL vials. Why is extra care needed?
AUsing the more concentrated vial by mistake would give a tenfold overdose
BHeparin concentration has no effect on safety
CThe concentrated vial is safer, because less volume is drawn up
DBoth vial strengths can be swapped freely
17.Lab values & electrolytesMedium
When is a peak level for an IV aminoglycoside such as gentamicin usually drawn?
AExactly 24 hours after the first dose
BAt any time convenient for the patient
CJust before the next dose is started
DAbout 30 minutes after the infusion ends
18.Lab values & electrolytesHard
A patient has marked generalized edema. Results show heavy proteinuria, serum albumin 1.8 g/dL (18 g/L) and total cholesterol 340 mg/dL (8.8 mmol/L). Which condition fits best?
ANephrotic syndrome
BLiver cirrhosis only
CPrerenal kidney injury
DAcute pyelonephritis
3Solutions
1.Nursing fundamentals
Answer: C · Sugar on the skin can give a falsely high reading
Why this is the answer
Traces of food or drink on the finger can raise the reading. Washing with water and drying fully gives an accurate result; alcohol wipes can also affect some meters.
Answer
C · Sugar on the skin can give a falsely high reading
2.Nursing fundamentals
Answer: A · Explain that losing appetite is a natural part of dying
Why this is the answer
As death approaches, the need for food and fluid falls. Forcing food causes distress and aspiration. Mouth care and small amounts on request keep the patient comfortable.
Answer
A · Explain that losing appetite is a natural part of dying
3.Clinical nursing
Answer: C · As a side effect or intolerance, not a true allergy
Why this is the answer
Constipation is a predictable side effect of opioids, not an immune response. Recording it accurately avoids withholding useful medicines while still noting the patient's experience.
Answer
C · As a side effect or intolerance, not a true allergy
4.Clinical nursing
Answer: D · Raised jugular venous pressure and lung crackles
Why this is the answer
Both types cause tachycardia, hypotension, cool skin and low urine output. In cardiogenic shock the failing heart causes venous congestion and pulmonary oedema, so large fluid boluses may worsen it.
Answer
D · Raised jugular venous pressure and lung crackles
5.Arterial blood gas interpretation
Answer: Osm = 332 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 = 2·150 + 27.8 + 4.3 = 332.1 ≈ 332 mOsm/kg
Answer
Osm = 332 mOsm/kg
6.Arterial blood gas interpretation
Answer: AGc = 23.5 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 = 136 − (102 + 14) = 20
Correction for albumin
20 + 0.25·(40 − 26) = 23.5 mmol/L
Answer
AGc = 23.5 mmol/L
Above about 12 after correction: a high anion gap.
7.Clinical assessment scores
Answer: M = 4
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.
Motor score
M = 11 − 3 − 4 = 4
M4: withdraws the limb from pressure (normal flexion)
Answer
M = 4
8.Clinical assessment scores
Answer: 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 18/min → 0
SpO₂ 99% → 0
on oxygen → 2
SBP 130 mmHg → 0
HR 50/min → 1
newly confused (C) → 3
T 36.9 °C → 0
Total and red scores
NEWS2 = 0 + 0 + 2 + 0 + 1 + 3 + 0 = 6
At least one parameter scores 3.
Risk group
medium
Answer
medium
A total of 5 or more calls for an urgent clinical response.
9.Enteral & parenteral nutrition calculations
Answer: R = 95 mL/h
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.
Energy needed
E = 25·61 = 1525 kcal/day
Daily volume
V = 1525/1 = 1525 mL/day
Pump rate
R = 1525/16 = 95.31 ≈ 95 mL/h
Answer
R = 95 mL/h
10.Enteral & parenteral nutrition calculations
Answer: E = 1774 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: 25·1200/100 = 300 g
amino acids: 4.25·1200/100 = 51 g
Kilocalories per component
dextrose: 300·3.4 = 1020 kcal
amino acids: 51·4 = 204 kcal
lipid: 500·1.1 = 550 kcal
Total energy
E = 1020 + 204 + 550 = 1774 kcal/day
Answer
E = 1774 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: ventricular tachycardia
Ventricular rhythms: ventricular tachycardia is a run of three or more wide (0.12 s or more) complexes in a row at more than 100/min, usually 150–250/min, regular, without related P waves. Ventricular fibrillation is a chaotic, irregular waveform with no identifiable P waves, QRS complexes or T waves and no countable rate. Asystole is an almost flat line with no ventricular activity; a flat line is always confirmed by checking the patient, the leads and the gain and a second lead. In resuscitation guidelines VF and pulseless VT are the shockable rhythms and asystole is not.
Five steps
1. Rate: R–R = 10 small boxes, 1500 ÷ 10 ≈ 150 per minute.
2. Rhythm: regular, every R–R is 0.40 s.
3. P waves: none identifiable.
4. PR interval: not measurable.
5. QRS: 0.14 s, wide (0.12 s or more).
Interpretation
ventricular tachycardia
Answer
ventricular tachycardia
In resuscitation guidelines VF and pulseless VT are the shockable rhythms. This is identification practice only.
13.Prioritization & delegation
Answer: A · Write the order down and read it back to the provider to confirm it
Why this is the answer
For telephone and verbal orders, the nurse writes down the full order and reads it back so the provider can confirm it. This “read-back” prevents errors from mishearing.
Answer
A · Write the order down and read it back to the provider to confirm it
14.Prioritization & delegation
Answer: A · A raised risk of suicide, because she may have made a decision
Why this is the answer
A sudden lift in mood with giving away belongings can mean the patient has decided to end her life. The nurse asks directly about suicidal thoughts and keeps her safe.
Answer
A · A raised risk of suicide, because she may have made a decision
15.Infection control & patient safety
Answer: B · Wear gloves, absorb the blood, then clean the area with an approved disinfectant
Why this is the answer
Blood spills are cleaned promptly by staff wearing gloves. The blood is absorbed with disposable material, then the area is cleaned and disinfected with a hospital disinfectant, and waste goes into clinical waste.
Answer
B · Wear gloves, absorb the blood, then clean the area with an approved disinfectant
16.Infection control & patient safety
Answer: A · Using the more concentrated vial by mistake would give a tenfold overdose
Why this is the answer
Mix-ups between heparin strengths have caused deaths. The nurse checks the concentration on the label every time and uses an independent double check, and many hospitals limit which strengths are stocked.
Answer
A · Using the more concentrated vial by mistake would give a tenfold overdose
17.Lab values & electrolytes
Answer: D · About 30 minutes after the infusion ends
Why this is the answer
Peak aminoglycoside levels are usually drawn about 30 minutes after a 30-minute infusion ends, to confirm the level is high enough to kill bacteria. Troughs, drawn just before the next dose, check for accumulation. Local protocols may differ, especially with once-daily dosing.
Answer
D · About 30 minutes after the infusion ends
18.Lab values & electrolytes
Answer: A · Nephrotic syndrome
Why this is the answer
Nephrotic syndrome is heavy proteinuria with low albumin, edema and high lipids. Low albumin reduces oncotic pressure, causing edema, and the liver increases lipoprotein production. There is also a higher risk of clots and infection.Checked against:Nephrotic syndrome · MedlinePlus (NIH) (2025)