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
A patient's radial pulse is irregular. How should you count it?
AFor a full 60 seconds, ideally at the apex of the heart
BOnly on the automatic blood pressure machine
CFor 10 seconds and multiply by six
DFor 15 seconds and multiply by four
2.Nursing fundamentalsHard
A patient who had a GCS of 15 this morning now opens their eyes only to voice and is confused. What should the nurse do?
ARecord it and recheck at the next routine time
BLet the patient sleep, as they are probably tired
CTreat it as deterioration and escalate urgently
DGive a sedative to calm the confusion
3.Clinical nursingMedium
Which drug is used to reverse unfractionated heparin?
AVitamin K (phytomenadione)
BFlumazenil
CNaloxone
DProtamine sulfate
4.Clinical nursingHard
Which sign is often a late finding in hypovolaemic shock in a young, previously fit adult?
AA slightly raised respiratory rate
BA fall in blood pressure
CA rise in heart rate
DCool peripheries
5.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.43, PaCO₂ 53 mmHg (7.1 kPa) and HCO₃⁻ 34 mmol/L. The primary disorder is metabolic alkalosis. How far is it compensated? Click your answer.
pH 7.43PaCO₂ 53 mmHg (7.1 kPa)HCO₃⁻ 34 mmol/L
1uncompensated
2partially compensated
3fully compensated
6.Arterial blood gas interpretationHard
A practice gas shows a respiratory acidosis: pH 7.29, PaCO₂ 83 mmHg (11.1 kPa), HCO₃⁻ 39 mmol/L. Use the rules ‘HCO₃⁻ rises 1 mmol/L per 10 mmHg (acute) or 3.5 mmol/L per 10 mmHg (chronic)’ to classify it. Click your answer.
pH 7.29PaCO₂ 83 mmHg (11.1 kPa)HCO₃⁻ 39 mmol/L
1acute
2chronic
3acute on chronic
7.Clinical assessment scoresMedium
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: yes; secondary diagnosis: yes; ambulatory aid: crutches, cane or walker; IV therapy or saline lock: yes; gait: impaired; mental status: knows own limits. Find the Morse total MFS.
0–125
MFS =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). An adult weighs 90 kg and is 195 cm tall. Calculate the BMI and click the WHO weight category.
Practice exercise (made-up values, not clinical guidance). A 69 kg adult (BMI below 30) needs 30 kcal/kg/day. The tube feed provides 1.2 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). A critically ill man is 165 cm tall and weighs 148 kg. The practice protocol gives 12 kcal/kg of actual body weight per day if the BMI is 30–50 kg/m², and 24 kcal/kg of ideal body weight (Devine) per day if the BMI is above 50 kg/m². Find the energy goal E in kcal/day. Round to the nearest whole number.
Interpret this lead II rhythm strip. Which rhythm is it? 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 arrhythmia
2sinus bradycardia
3sinus rhythm with sinus arrest
4normal sinus rhythm
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
A young adult has just started an SSRI antidepressant for major depression. What should the nurse monitor most closely in the first weeks?
AWeight loss from too much appetite
BHair growth and skin color
CThoughts of suicide or self-harm
DRising blood glucose levels
14.Prioritization & delegationHard
Which finding most suggests a tension pneumothorax rather than a simple pneumothorax?
ATrachea shifted away from the affected side, with low blood pressure
BMild breathlessness with reduced breath sounds on one side of the chest only
CA small air leak seen on a routine chest X-ray
DSharp chest pain that is worse on deep breathing
15.Infection control & patient safetyMedium
When putting on sterile gloves, how does the nurse put on the second glove?
AUse the bare hand to adjust the outside of the first glove
BHold the inside of the second glove with the gloved hand
CPull the second glove on by its fingertips, using the bare hand
DSlide the gloved fingers under the second glove’s cuff and pull it on
16.Infection control & patient safetyHard
In a mass-casualty incident with limited resources, why may a critically injured patient with little chance of survival receive care after others?
APatients are treated in the order they arrive
BThe most severely injured are never given comfort care
CResources go first to those most likely to survive with treatment
DCritical patients are always treated last in every situation, even outside disasters
17.Lab values & electrolytesMedium
A patient takes valproate (valproic acid) for epilepsy. Which tests are monitored regularly?
ATroponin and B-type natriuretic peptide
BLiver function tests and platelet count
CSerum lithium and urine specific gravity
DThyroid function and serum calcium
18.Lab values & electrolytesHard
A patient with acute kidney injury has a potassium of 6.8 mEq/L despite medical treatment, a pH of 7.12 and pulmonary edema not responding to diuretics. Which treatment is most likely needed?
AUrgent dialysis
BMore oral fluid
CAn IV magnesium dose
DA potassium supplement
3Solutions
1.Nursing fundamentals
Answer: A · For a full 60 seconds, ideally at the apex of the heart
Why this is the answer
An irregular pulse should be counted for a full minute. An apical count with a stethoscope is more accurate, as some beats may be too weak to feel at the wrist.
Answer
A · For a full 60 seconds, ideally at the apex of the heart
2.Nursing fundamentals
Answer: C · Treat it as deterioration and escalate urgently
Why this is the answer
The score has dropped to about 13. Any new fall in consciousness or new confusion needs urgent escalation, a full ABCDE assessment and a check of glucose.
Answer
C · Treat it as deterioration and escalate urgently
3.Clinical nursing
Answer: D · Protamine sulfate
Why this is the answer
Protamine binds heparin and neutralises it. Vitamin K is used for warfarin.
Answer
D · Protamine sulfate
4.Clinical nursing
Answer: B · A fall in blood pressure
Why this is the answer
Young adults compensate for blood loss with tachycardia and vasoconstriction, so blood pressure may stay normal until a large volume is lost. Hypotension is therefore a late and serious sign.
Answer
B · A fall in blood pressure
5.Arterial blood gas interpretation
Answer: fully compensated
Reading a blood gas (ROME): first the pH: below 7.35 is acidaemia, above 7.45 alkalaemia. Then find the value that explains it. PaCO₂ (normal 35–45 mmHg, 4.7–6.0 kPa) is the respiratory part and moves Opposite to the pH in a respiratory disorder; HCO₃⁻ (normal 22–26 mmol/L) is the metabolic part and moves in the same direction as the pH (Respiratory Opposite, Metabolic Equal). The other value shows the compensation: normal means uncompensated; abnormal in the direction that pulls the pH back while the pH is still abnormal means partially compensated; a normal pH with both values abnormal means fully compensated. Ranges differ slightly between laboratories; these are practice values.
ROME, value by value
pH 7.43: within 7.35–7.45
PaCO₂ 53 mmHg: high (35–45)
HCO₃⁻ 34 mmol/L: high (22–26)
Compensation
Clinically, also check the expected compensation: for a metabolic alkalosis PaCO₂ ≈ 0.7·HCO₃⁻ + 21 = 42.8–46.8 mmHg, so the measured 53 mmHg points to an additional respiratory acidosis (a mixed disorder). The answer above is the ROME exam classification.
fully compensated
Answer
fully compensated
6.Arterial blood gas interpretation
Answer: chronic
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.
Expected HCO₃⁻
acute: 24 + 1·4.3 = 28.3 mmol/L
chronic: 24 + 3.5·4.3 = 39.05 mmol/L
Compare
measured: 39 mmol/L → chronic
Answer
chronic
7.Clinical assessment scores
Answer: MFS = 95
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: yes → 25
secondary diagnosis: yes → 15
ambulatory aid: crutches, cane or walker → 15
IV therapy or saline lock: yes → 20
gait: impaired → 20
mental status: knows own limits → 0
Add
Morse total = 25 + 15 + 15 + 20 + 20 + 0 = 95
Answer
MFS = 95
8.Clinical assessment scores
Answer: healthy weight
Body mass index: BMI = weight (kg)/height (m)², with the height converted to metres first. With pounds and inches, BMI = 703 × weight (lb)/height (in)². WHO adult categories: below 18.5 underweight, 18.5–24.9 healthy weight, 25.0–29.9 overweight, 30.0–34.9 obesity class I, 35.0–39.9 obesity class II and 40 or more obesity class III.
BMI
BMI = 90/1.95² = 23.67
Category
healthy weight
Answer
healthy weight
9.Enteral & parenteral nutrition calculations
Answer: R = 72 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 = 30·69 = 2070 kcal/day
Daily volume
V = 2070/1.2 = 1725 mL/day
Pump rate
R = 1725/24 = 71.88 ≈ 72 mL/h
Answer
R = 72 mL/h
10.Enteral & parenteral nutrition calculations
Answer: E = 1474 kcal/day
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. Obesity in critical illness (ASPEN/SCCM 2016): BMI = weight/height² (kg/m²). For BMI 30–50 the energy goal is 11–14 kcal/kg of actual body weight per day; above 50 it is 22–25 kcal/kg of ideal body weight per day. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Body mass index
BMI = 148/1.65² = 54.36 kg/m²
Ideal body weight (Devine)
165 cm/2.54 = 64.96 in
IBW = 50 + 2.3·(64.96 − 60) = 61.41 kg
Energy goal
BMI above 50: kcal per kg of ideal body weight.
E = 24·61.41 = 1474 kcal/day
Answer
E = 1474 kcal/day
11.ECG rhythm strip interpretation
Answer: sinus rhythm with sinus arrest
Rhythm criteria (lead II): sinus rhythm has an upright P wave before every QRS, a constant PR of 0.12–0.20 s and a narrow QRS: normal sinus rhythm at 60–100/min, sinus bradycardia below 60, sinus tachycardia above 100. Atrial fibrillation: no P waves, a fibrillatory baseline and an irregularly irregular R–R. Atrial flutter: sawtooth flutter waves at about 250–350/min with a fixed conduction ratio such as 2:1 or 4:1. First-degree AV block: sinus rhythm with a constant PR above 0.20 s. Junctional rhythm: narrow QRS at 40–60/min with absent or inverted P waves (PR below 0.12 s, or P after the QRS). A PVC is an early, wide (0.12 s or more), bizarre QRS without a P wave, with the T wave in the opposite direction and usually a full compensatory pause; in bigeminy every second beat is a PVC. 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).
Five steps
1. Rate: 7 QRS complexes in 6 s, × 10 = 70 per minute.
2. Rhythm: regular (R–R 0.72 s) except for one pause of 1.72 s, which is not a whole number of P–P cycles.
3. P waves: upright, one before every QRS; no P wave at all during the pause.
4. PR interval: 0.14 s, constant, within 0.12–0.20 s.
5. QRS: 0.10 s, narrow (below 0.12 s).
Interpretation
sinus rhythm with sinus arrest
Answer
sinus rhythm with sinus arrest
12.ECG rhythm strip interpretation
Answer: atrial rate = 75 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 = 20 small boxes = 0.80 s → 1500 ÷ 20 = 75 ≈ 75 per minute
Ventricular rate
R–R = 40 small boxes = 1.60 s → 1500 ÷ 40 = 37.5 ≈ 38 per minute
Answer
atrial rate = 75 bpm
Answer
atrial rate = 75 bpm
2:1 AV block: every second P wave is not conducted, so the atrial rate is twice the ventricular rate.
13.Prioritization & delegation
Answer: C · Thoughts of suicide or self-harm
Why this is the answer
In the early weeks of antidepressant treatment, especially in young people, suicidal thoughts may increase. Patients and families are taught to report them at once.
Answer
C · Thoughts of suicide or self-harm
14.Prioritization & delegation
Answer: A · Trachea shifted away from the affected side, with low blood pressure
Why this is the answer
In tension pneumothorax, trapped air pushes the mediastinum to the other side, reducing venous return and blood pressure. It is life-threatening and needs immediate decompression.
Answer
A · Trachea shifted away from the affected side, with low blood pressure
15.Infection control & patient safety
Answer: D · Slide the gloved fingers under the second glove’s cuff and pull it on
Why this is the answer
The first glove is handled only by the inside of its cuff with the bare hand. The gloved hand then touches only the outside of the second glove, under its folded cuff. The inside of a glove is not sterile once skin has touched it.
Answer
D · Slide the gloved fingers under the second glove’s cuff and pull it on
16.Infection control & patient safety
Answer: C · Resources go first to those most likely to survive with treatment
Why this is the answer
In disasters, triage shifts from treating the sickest first to saving the most lives with available resources. Expectant patients still receive comfort care and are reassessed as resources change.
Answer
C · Resources go first to those most likely to survive with treatment
17.Lab values & electrolytes
Answer: B · 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)
Answer
B · Liver function tests and platelet count
18.Lab values & electrolytes
Answer: A · Urgent dialysis
Why this is the answer
Indications for urgent dialysis in AKI include refractory hyperkalemia, severe metabolic acidosis, fluid overload not responding to diuretics, uremic complications and some poisonings. This patient has three of them.Checked against:Acute tubular necrosis · MedlinePlus (NIH) (2025)