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 is body mass index (BMI) calculated?
AWaist size divided by hip size
BHeight in centimetres divided by weight in kilograms
CWeight in kilograms multiplied by height in metres squared
DWeight in kilograms divided by height in metres squared
2.Nursing fundamentalsHard
On the day after surgery, a patient's new stoma has turned dark purple. What should the nurse do?
AReport it urgently, as the stoma may be losing its blood supply
BClean it firmly to remove the colour
CRecord it as normal bruising after surgery and recheck tomorrow
DWait a week to see whether it changes
3.Clinical nursingMedium
After removing a peripheral IV cannula, what should the nurse check?
AThat the cannula is put back in its sterile packet for the next patient
BThat the cannula is intact, and apply pressure until bleeding stops
CThat the patient's blood glucose is normal before removal
DThat the site is left uncovered and bleeding freely
4.Clinical nursingHard
A patient taking dapagliflozin is vomiting and unwell, with high blood ketones and a blood glucose of only 11 mmol/L (198 mg/dL). What should be suspected?
AHypoglycaemia
BEuglycaemic diabetic ketoacidosis
CHyperosmolar hyperglycaemic state
DSimple gastroenteritis with no further concern
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 129 mmol/L, glucose 29.6 mmol/L and urea 3.1 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 129 mmol/Lglucose 29.6 mmol/Lurea 3.1 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
A practice gas shows a metabolic alkalosis with HCO₃⁻ 40 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 40 mmol/L
PaCO₂ = mmHg
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice chart records GCS 9, with E3 and V2. What motor score M was recorded, and which response does it describe? Give the number.
GCS 9E3V2
M =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). An adult weighs 112 kg and is 188 cm tall. Calculate the BMI and click the WHO weight category.
Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a man who is 188 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 1000 mL of parenteral nutrition with final concentrations of 25% dextrose and 5% amino acids, plus 500 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
1000 mLdextrose 25%amino acids 5%lipid 500 mL · 2 kcal/mL
NPC = kcal/day
11.ECG rhythm strip interpretationMedium
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
1normal sinus rhythm
2sinus bradycardia
3sinus tachycardia
4junctional rhythm
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 fibrillation
2ventricular tachycardia
3atrial fibrillation
4torsades de pointes
13.Prioritization & delegationMedium
A parent of a child with influenza talks with the nurse. Which statement shows a need for further teaching?
A“I will keep my child home from school and away from others while unwell.”
B“I will give my child aspirin to bring the fever down.”
C“I will give my child plenty of fluids.”
D“I will call if my child has trouble breathing.”
14.Prioritization & delegationHard
An older patient with pneumonia is newly confused. Which action comes first?
AApply wrist restraints to stop the patient pulling at the IV
BCheck oxygen saturation and the other vital signs
CAsk the family whether this is normal for the patient
DGive a prescribed as-needed sedative
15.Infection control & patient safetyMedium
A patient is admitted to an inpatient mental health unit. Why are personal belongings checked?
ATo decide which family members may visit
BTo remove items that could be used to harm self or others
CTo make a list of valuable items for insurance
DTo find out what the patient likes to wear during the hospital stay
16.Infection control & patient safetyHard
A nurse floated to an unfamiliar unit is asked to manage a device they have never been trained to use. What should the nurse do?
ADo it anyway, using only the device manual and the instructions on the screen
BLeave the device untouched and not tell anyone
CAsk the patient or the family to explain how the device works
DTell the charge nurse and ask for help or a change of assignment
17.Lab values & electrolytesMedium
A patient takes low-dose methotrexate weekly for rheumatoid arthritis. Which laboratory tests are monitored regularly?
ASerum amylase, lipase and blood ketones
BComplete blood count, liver tests and kidney function
CSerum lithium, sodium and urine specific gravity
DTroponin, creatine kinase and myoglobin
18.Lab values & electrolytesHard
Which patient's result should the nurse act on first?
APlatelets 140 × 10³/µL in a patient with mild chronic liver disease
BFerritin 15 ng/mL in a well patient with known iron-deficiency anemia on oral iron
CHemoglobin 6.4 g/dL (64 g/L) with new chest pain and a pulse of 124/min
DHemoglobin 9.6 g/dL (96 g/L) in a patient with stable chronic kidney disease
3Solutions
1.Nursing fundamentals
Answer: D · Weight in kilograms divided by height in metres squared
Why this is the answer
BMI = weight (kg) ÷ height² (m²). For example, 70 kg and 1.75 m gives about 22.9 kg/m². It is a screening measure and does not show body composition.
Answer
D · Weight in kilograms divided by height in metres squared
2.Nursing fundamentals
Answer: A · Report it urgently, as the stoma may be losing its blood supply
Why this is the answer
A dusky, purple or black stoma suggests ischaemia or necrosis, which can need surgery. The nurse reports it to the surgical team at once.
Answer
A · Report it urgently, as the stoma may be losing its blood supply
3.Clinical nursing
Answer: B · That the cannula is intact, and apply pressure until bleeding stops
Why this is the answer
The nurse checks that the whole cannula has been removed, applies pressure and a dressing, and records the removal. Any signs of phlebitis are noted.
Answer
B · That the cannula is intact, and apply pressure until bleeding stops
4.Clinical nursing
Answer: B · Euglycaemic diabetic ketoacidosis
Why this is the answer
SGLT2 inhibitors can cause DKA with near-normal or modestly raised glucose because glucose is lost in the urine. Ketones should be checked in unwell patients on these drugs.
Answer
B · Euglycaemic diabetic ketoacidosis
5.Arterial blood gas interpretation
Answer: Osm = 291 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 = 2·129 + 29.6 + 3.1 = 290.7 ≈ 291 mOsm/kg
Answer
Osm = 291 mOsm/kg
6.Arterial blood gas interpretation
Answer: PaCO₂ = 49 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.
Expected PaCO₂
0.7·40 + 21 = 49 mmHg
Answer
PaCO₂ = 49 mmHg
The rise has a limit: PaCO₂ rarely goes above about 55 mmHg from compensation alone.
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 = 9 − 3 − 2 = 4
M4: withdraws the limb from pressure (normal flexion)
Answer
M = 4
8.Clinical assessment scores
Answer: obesity class I
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 = 112/1.88² = 31.69
Category
obesity class I
Answer
obesity class I
9.Enteral & parenteral nutrition calculations
Answer: IBW = 82.2 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
188 cm/2.54 = 74.02 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(74.02 − 60) = 82.24 ≈ 82.2 kg
Answer
IBW = 82.2 kg
10.Enteral & parenteral nutrition calculations
Answer: NPC = 1850 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: 25·1000/100 = 250 g
amino acids: 5·1000/100 = 50 g
Kilocalories per component
dextrose: 250·3.4 = 850 kcal
amino acids: 50·4 = 200 kcal
lipid: 500·2 = 1000 kcal
Non-protein energy
NPC = 850 + 1000 = 1850 kcal/day
Answer
NPC = 1850 kcal/day
11.ECG rhythm strip interpretation
Answer: sinus bradycardia
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.
Five steps
1. Rate: R–R = 34 small boxes, 1500 ÷ 34 ≈ 44 per minute.
2. Rhythm: regular, every R–R is 1.36 s.
3. P waves: upright, one before every QRS, all alike.
4. PR interval: 0.20 s, constant, within 0.12–0.20 s.
5. QRS: 0.08 s, narrow (below 0.12 s).
Interpretation
sinus bradycardia
Answer
sinus bradycardia
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: 0.16 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: B · “I will give my child aspirin to bring the fever down.”
Why this is the answer
Aspirin in children with viral illnesses such as influenza or chickenpox is linked to Reye syndrome. Fluids, rest at home and reporting breathing trouble are correct.
Answer
B · “I will give my child aspirin to bring the fever down.”
14.Prioritization & delegation
Answer: B · Check oxygen saturation and the other vital signs
Why this is the answer
New confusion can be caused by hypoxia, sepsis or low blood glucose. Assessing oxygenation and vital signs comes first. Restraints and sedatives treat the behavior, not the cause, and can make delirium worse.
Answer
B · Check oxygen saturation and the other vital signs
15.Infection control & patient safety
Answer: B · To remove items that could be used to harm self or others
Why this is the answer
Belongings are searched with the patient, according to policy, for items such as sharp objects, cords, drugs and lighters. These are stored safely to reduce the risk of self-harm or violence.
Answer
B · To remove items that could be used to harm self or others
16.Infection control & patient safety
Answer: D · Tell the charge nurse and ask for help or a change of assignment
Why this is the answer
Accepting a task beyond one’s competence puts the patient at risk. The nurse explains the limit to the charge nurse, who can arrange help, training or reassignment.
Answer
D · Tell the charge nurse and ask for help or a change of assignment
17.Lab values & electrolytes
Answer: B · Complete blood count, liver tests and kidney function
Why this is the answer
Methotrexate can cause bone marrow suppression, liver toxicity and, as it is cleared by the kidneys, toxicity when kidney function falls. The CBC, liver tests and creatinine are checked regularly, and folic acid is usually given to reduce adverse effects.
Answer
B · Complete blood count, liver tests and kidney function
18.Lab values & electrolytes
Answer: C · Hemoglobin 6.4 g/dL (64 g/L) with new chest pain and a pulse of 124/min
Why this is the answer
Severe anemia with chest pain and tachycardia suggests the heart is not receiving enough oxygen, which needs urgent action, often including transfusion. The other results are mildly abnormal but expected or stable.
Answer
C · Hemoglobin 6.4 g/dL (64 g/L) with new chest pain and a pulse of 124/min