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
How does pursed-lip breathing help a patient with COPD?
AIt makes the patient breathe faster to take in more air
BIt replaces the need for inhaled medicines
CIt increases the amount of carbon dioxide in the blood
DIt keeps the airways open longer and slows the breathing
2.Nursing fundamentalsHard
An older woman with severe arthritis has normal bladder control but wets herself because she cannot reach the toilet in time. Which type of incontinence is this?
AFunctional incontinence
BStress incontinence
COverflow incontinence
DUrge incontinence
3.Clinical nursingMedium
A patient on peritoneal dialysis notices the drained fluid has become cloudy and has abdominal pain. What is likely?
APeritonitis
BNormal dialysis fluid
CA urinary tract infection
DConstipation
4.Clinical nursingHard
Which action is correct when caring for a chest drain with an underwater seal?
AClamp the tube routinely during every transfer or bed move
BKeep the drainage bottle below the level of the chest
CRemove the water from the bottle to prevent spills
DLift the bottle above the patient to empty it
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 70 mmHg (9.3 kPa). Use the rule that in acute respiratory acidosis HCO₃⁻ rises by 1 mmol/L for every 10 mmHg that PaCO₂ is above 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.
Practice values: Na⁺ 146, Cl⁻ 113 and HCO₃⁻ 17 mmol/L. Calculate the delta ratio (AG − 12)/(24 − HCO₃⁻), using AG = Na⁺ − (Cl⁻ + HCO₃⁻). Give two decimals.
Na⁺ 146 mmol/LCl⁻ 113 mmol/LHCO₃⁻ 17 mmol/L
delta ratio =
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice patient after a head injury opens the eyes when spoken to, is oriented to person, place and time and shows as the best motor response: moves a hand to the site of pressure (localises). 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 12/min, SpO₂ 89% on supplemental oxygen, blood pressure 142/86 mmHg, pulse 82/min, alert, temperature 39.2 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). A 60 kg adult (BMI below 30) needs 25 kcal/kg/day. The tube feed provides 1.5 kcal/mL and runs by pump for 24 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 1500 mL of parenteral nutrition with final concentrations of 10% dextrose and 3.5% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
1500 mLdextrose 10%amino acids 3.5%lipid 250 mL · 2 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 Fridericia’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
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
1sinus bradycardia
2asystole
3junctional rhythm
4idioventricular rhythm
13.Prioritization & delegationMedium
A drowsy patient who has just returned from surgery starts to vomit. What should the nurse do first?
ARaise the legs above the heart
BGive an oral anti-sickness tablet
CTurn the patient onto their side
DGive a drink of water
14.Prioritization & delegationHard
A patient opens their eyes only to pain, uses inappropriate words and withdraws from pain. What is the Glasgow Coma Scale score?
A7
B13
C11
D9
15.Infection control & patient safetyMedium
Why is “QD” (once daily) on The Joint Commission’s “Do Not Use” list?
AIt means “every day at bedtime” in some hospitals
BIt is a Latin abbreviation, and only plain English abbreviations may be used
CIt can be misread as QID or QOD, so the drug is given too often or too rarely
DIt is only allowed for intravenous medicines
16.Infection control & patient safetyHard
Why can a patient with severe neutropenia have a serious infection but little redness, swelling or pus?
AAntibiotics given with chemotherapy hide all signs of infection
BThere are too few neutrophils to produce the usual inflammatory signs
CNeutropenia makes infections stay limited to the skin
DChemotherapy kills the bacteria before they can multiply
17.Lab values & electrolytesMedium
A patient with an upper gastrointestinal bleed has a BUN of 48 mg/dL (urea 17 mmol/L) and a normal creatinine. What is the most likely explanation?
ADigested blood adds protein, which the liver turns into urea
BThe kidneys have suddenly lost most of their function
CThe liver has stopped making urea because of the bleeding
DSkeletal muscle is breaking down because of the blood loss
18.Lab values & electrolytesHard
The nurse teaches a patient who is collecting a 24-hour urine sample at home. Which statement shows a need for further teaching?
A"If I forget to save one void, I'll just carry on to the end"
B"I'll keep the container cool as the laboratory told me to"
C"I'll ask whether any foods or drugs should be avoided first"
D"I'll empty my bladder at the end time and add that urine"
3Solutions
1.Nursing fundamentals
Answer: D · It keeps the airways open longer and slows the breathing
Why this is the answer
Breathing out slowly through pursed lips creates back-pressure that keeps small airways open, helping to empty trapped air and reducing breathlessness.
Answer
D · It keeps the airways open longer and slows the breathing
2.Nursing fundamentals
Answer: A · Functional incontinence
Why this is the answer
Functional incontinence is caused by problems outside the urinary tract, such as poor mobility or confusion. A commode near the bed, easy clothing and regular toileting help.
Answer
A · Functional incontinence
3.Clinical nursing
Answer: A · Peritonitis
Why this is the answer
Cloudy effluent with abdominal pain or fever suggests peritonitis, the main serious complication of peritoneal dialysis. The fluid is sent for culture and treatment started promptly.
Answer
A · Peritonitis
4.Clinical nursing
Answer: B · Keep the drainage bottle below the level of the chest
Why this is the answer
The bottle stays below chest level so fluid and air cannot return to the pleural space. Routine clamping can cause a tension pneumothorax.
Answer
B · Keep the drainage bottle below the level of the chest
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 27 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.
Change in PaCO₂
|70 − 40| = 30 mmHg → 3 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 1·3 = 27 mmol/L
Answer
HCO₃⁻ = 27 mmol/L
6.Arterial blood gas interpretation
Answer: delta ratio = 0.5714
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 = 146 − (113 + 17) = 16
Delta ratio
(16 − 12)/(24 − 17) = 4/7 = 0.5714
Answer
delta ratio = 0.5714
Below 1: an added normal anion gap acidosis.
7.Clinical assessment scores
Answer: mild
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 when spoken to → 3
V: is oriented to person, place and time → 5
M: moves a hand to the site of pressure (localises) → 5
Add
GCS = 3 + 5 + 5 = 13
Severity
GCS 13 → mild
Answer
mild
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 12/min → 0
SpO₂ 89% → 3
on oxygen → 2
SBP 142 mmHg → 0
HR 82/min → 0
alert (A) → 0
T 39.2 °C → 2
Total and red scores
NEWS2 = 0 + 3 + 2 + 0 + 0 + 0 + 2 = 7
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: R = 42 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 = 25·60 = 1500 kcal/day
Daily volume
V = 1500/1.5 = 1000 mL/day
Pump rate
R = 1000/24 = 41.67 ≈ 42 mL/h
Answer
R = 42 mL/h
10.Enteral & parenteral nutrition calculations
Answer: E = 1220 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: 3.5·1500/100 = 52.5 g
Kilocalories per component
dextrose: 150·3.4 = 510 kcal
amino acids: 52.5·4 = 210 kcal
lipid: 250·2 = 500 kcal
Total energy
E = 510 + 210 + 500 = 1220 kcal/day
Answer
E = 1220 kcal/day
11.ECG rhythm strip interpretation
Answer: QTc = 0.415 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 = 10.5 × 0.04 = 0.42 s
RR = 26 × 0.04 = 1.04 s
Fridericia’s formula
QTc = 0.42/∛1.04 = 0.42/1.013 = 0.415 s
Answer
QTc = 0.415 s
Within the usual limits (about 0.45 s for men, 0.46 s for women). (415 ms)
12.ECG rhythm strip interpretation
Answer: idioventricular rhythm
More ventricular rhythms: torsades de pointes is a polymorphic ventricular tachycardia, usually 150–250/min, in which the wide complexes change in height and twist around the baseline, pointing up for a few beats and then down. Textbooks link it to a prolonged QT interval, and magnesium sulfate is the drug resuscitation guidelines name for it. An idioventricular rhythm is a ventricular escape rhythm: regular, wide QRS (0.12 s or more), no P waves, at 20–40/min (an accelerated idioventricular rhythm runs at 40–100/min). Monomorphic VT has identical wide complexes at more than 100/min. VF is chaotic, without any repeating complex.
Five steps
1. Rate: R–R = 48 small boxes, 1500 ÷ 48 ≈ 31 per minute.
2. Rhythm: regular, every R–R is 1.92 s.
3. P waves: none identifiable.
4. PR interval: not measurable.
5. QRS: 0.18 s, wide (0.12 s or more) and bizarre, with the T wave pointing the other way.
Interpretation
idioventricular rhythm
Answer
idioventricular rhythm
An idioventricular rhythm is an escape rhythm: the ventricles take over because the pacemakers above them have failed.
13.Prioritization & delegation
Answer: C · Turn the patient onto their side
Why this is the answer
A drowsy patient who vomits can aspirate. Turning them to the side lets vomit drain from the mouth; suction and a prescribed antiemetic follow.
Answer
C · Turn the patient onto their side
14.Prioritization & delegation
Answer: D · 9
Why this is the answer
Eyes open to pain scores 2, inappropriate words score 3 and withdrawal from pain scores 4, giving 9. A score of 8 or less often means the patient cannot protect their airway.
Answer
D · 9
15.Infection control & patient safety
Answer: C · It can be misread as QID or QOD, so the drug is given too often or too rarely
Why this is the answer
“QD” and “QOD” can be confused with each other and with “QID”, leading to serious dosing errors. The word “daily” or “every other day” is written in full instead.
Answer
C · It can be misread as QID or QOD, so the drug is given too often or too rarely
16.Infection control & patient safety
Answer: B · There are too few neutrophils to produce the usual inflammatory signs
Why this is the answer
Classic signs of infection come from the inflammatory response, which depends on white blood cells. With very few neutrophils, fever may be the only early sign, so it must be taken seriously.
Answer
B · There are too few neutrophils to produce the usual inflammatory signs
17.Lab values & electrolytes
Answer: A · Digested blood adds protein, which the liver turns into urea
Why this is the answer
Blood in the upper gut is digested, and the absorbed protein is converted to urea, so the BUN rises out of proportion to the creatinine. Reduced kidney blood flow from volume loss can add to the rise.Checked against:BUN - blood test · MedlinePlus (NIH) (2025)
Answer
A · Digested blood adds protein, which the liver turns into urea
18.Lab values & electrolytes
Answer: A · "If I forget to save one void, I'll just carry on to the end"
Why this is the answer
A 24-hour collection is valid only if every void in the period is saved; if a void is lost, the nurse or clinic is told and the collection is usually restarted. Keeping the container cool as instructed, adding the final void at the end time and asking about restrictions are correct.Checked against:Urine 24-hour volume · MedlinePlus (NIH) (2025)
Answer
A · "If I forget to save one void, I'll just carry on to the end"