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 are patients with a new ileostomy at risk of dehydration?
AThey are not allowed to drink for several weeks after surgery
BThe stoma absorbs water from the body
CThe output is liquid and contains a lot of water and salt
DThe colon removes too much water from the stool
2.Nursing fundamentalsHard
A patient with capacity refuses a prescribed treatment. What should the nurse do?
ARespect the refusal, make sure they understand the consequences, inform the team and document it
BAsk a relative to consent instead
CHide the medicine in the patient's food
DGive the treatment anyway, because it was prescribed and the doctor has decided it is in their best interests
3.Clinical nursingMedium
Which ECG change is typical of hypokalaemia?
AA very short PR interval with a delta wave
BTall, peaked T waves
CST elevation in leads II, III and aVF
DFlattened T waves and prominent U waves
4.Clinical nursingHard
A patient has a full-thickness burn all the way round the forearm. Which complication must be watched for closely?
AHypoglycaemia caused by the body using glucose to heal the burn
BExcessive bleeding from the burn surface needing an urgent blood transfusion
CLoss of circulation to the hand as swelling builds under tight burned skin
DDelayed hair growth on the arm
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 29 mmHg (3.9 kPa). Use the rule that in acute respiratory alkalosis HCO₃⁻ falls by 2 mmol/L for every 10 mmHg that PaCO₂ is below 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.
A practice gas shows a metabolic alkalosis with HCO₃⁻ 36 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 36 mmol/L
PaCO₂ = mmHg
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 28/min, SpO₂ 96% on supplemental oxygen, blood pressure 142/86 mmHg, pulse 64/min, alert, temperature 39.2 °C. What is the NEWS2 total score?
RR 28SpO₂ 96%O₂SBP 142HR 64AT 39.2 °C
NEWS2 =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). The team aims for a mean arterial pressure of at least 65 mmHg. A patient’s systolic pressure is 83 mmHg. Using MAP = (SBP + 2·DBP)/3, what is the lowest diastolic pressure DBP that still gives a MAP of 65 mmHg?
Practice exercise (made-up values, not clinical guidance). A 70 kg patient needs 1.2 g of protein per kg a day. The tube feed contains 68 g of protein per litre and runs at 45 mL/h for 16 hours a day. How many grams of extra protein ΔP a day are still needed? Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). A critically ill man is 182 cm tall and weighs 150 kg. The practice protocol gives 14 kcal/kg of actual body weight per day if the BMI is 30–50 kg/m², and 25 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.
This lead II strip shows atrial flutter. Measure the flutter-wave interval and find the atrial rate in beats per minute.
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
12.ECG rhythm strip interpretationHard
This lead II strip shows a conduction problem between the atria and the ventricles. 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
1second-degree AV block type I (Wenckebach)
2second-degree AV block type II
3sinus bradycardia
4third-degree (complete) AV block
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 give my child plenty of fluids.”
B“I will give my child aspirin to bring the fever down.”
C“I will keep my child home from school and away from others while unwell.”
D“I will call if my child has trouble breathing.”
14.Prioritization & delegationHard
Which patient is the most appropriate to assign to an LPN/LVN?
AA patient who has just arrived from the emergency department with pneumonia and confusion
BA patient with a tracheostomy placed this morning who is coughing up blood
CA patient on a new IV medication that needs frequent titration
DA patient with a long-standing tracheostomy who needs routine suctioning and care
15.Infection control & patient safetyMedium
An order reads “Give potassium chloride by IV push.” What should the nurse do?
AGive it slowly by IV push over two minutes while watching the cardiac monitor
BGive half by IV push and the rest later
CDilute it in a small syringe and push it
DNot give it, and contact the prescriber, because it is never given by IV push
16.Infection control & patient safetyHard
A patient’s WBC is 4,000/mm3, with 30% neutrophils and 5% bands. What is the absolute neutrophil count (ANC)?
A140/mm3
B1,200/mm3
C1,400/mm3
D3,500/mm3
17.Lab values & electrolytesMedium
A patient’s hemoglobin is 7.8 g/dL (78 g/L). Which findings would the nurse expect?
AFatigue, pallor, a fast heart rate and breathlessness on exertion
BA slow heart rate, flushed skin and a high blood pressure
CItching, yellow skin and dark urine
DHeadache, nosebleeds and a red face
18.Lab values & electrolytesHard
A patient with suspected Cushing syndrome takes dexamethasone at night. The next morning, the cortisol is still high. What does this suggest?
AThe result is normal, as dexamethasone raises cortisol
BCortisol is being produced without normal feedback control
CThe patient has primary hypothyroidism instead
DThe adrenal glands are not able to produce enough cortisol
3Solutions
1.Nursing fundamentals
Answer: C · The output is liquid and contains a lot of water and salt
Why this is the answer
The colon normally reabsorbs water and salt. An ileostomy bypasses it, so high output can quickly cause dehydration and low sodium; output is monitored and fluids encouraged.
Answer
C · The output is liquid and contains a lot of water and salt
2.Nursing fundamentals
Answer: A · Respect the refusal, make sure they understand the consequences, inform the team and document it
Why this is the answer
An adult with capacity may refuse treatment. The nurse should explore the reasons, give information, inform the prescriber and document. Covert administration without proper legal process is not acceptable.
Answer
A · Respect the refusal, make sure they understand the consequences, inform the team and document it
3.Clinical nursing
Answer: D · Flattened T waves and prominent U waves
Why this is the answer
Low potassium causes flattened or inverted T waves, ST depression and U waves. It increases the risk of arrhythmias, especially in patients on digoxin.
Answer
D · Flattened T waves and prominent U waves
4.Clinical nursing
Answer: C · Loss of circulation to the hand as swelling builds under tight burned skin
Why this is the answer
Circumferential full-thickness burns form a tight eschar that acts like a tourniquet as oedema develops. Neurovascular checks are needed, and escharotomy may be required.
Answer
C · Loss of circulation to the hand as swelling builds under tight burned skin
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 21.8 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
|29 − 40| = 11 mmHg → 1.1 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 − 2·1.1 = 21.8 mmol/L
Answer
HCO₃⁻ = 21.8 mmol/L
6.Arterial blood gas interpretation
Answer: PaCO₂ = 46.2 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
0.7·36 + 21 = 46.2 mmHg
Answer
PaCO₂ = 46.2 mmHg
The rise has a limit: PaCO₂ rarely goes above about 55 mmHg from compensation alone.
7.Clinical assessment scores
Answer: NEWS2 = 7
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 28/min → 3
SpO₂ 96% → 0
on oxygen → 2
SBP 142 mmHg → 0
HR 64/min → 0
alert (A) → 0
T 39.2 °C → 2
Add
NEWS2 = 3 + 0 + 2 + 0 + 0 + 0 + 2 = 7
Answer
NEWS2 = 7
8.Clinical assessment scores
Answer: DBP = 56 mmHg
Blood pressure values: pulse pressure PP = SBP − DBP. Mean arterial pressure MAP ≈ (SBP + 2·DBP)/3 = DBP + PP/3, an estimate based on the heart spending about two thirds of each beat in diastole at a normal heart rate (less accurate when the heart rate is fast); a MAP of at least about 65 mmHg is a common target for organ perfusion. The shock index SI = heart rate/SBP is normally about 0.5–0.7; a value above about 1 is a warning sign of shock.
Rearrange
DBP = (3·MAP − SBP)/2
Substitute
DBP = (3·65 − 83)/2 = 112/2 = 56 mmHg
Answer
DBP = 56 mmHg
9.Enteral & parenteral nutrition calculations
Answer: ΔP = 35 g/day
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.
Protein needed
1.2·70 = 84 g/day
Protein from the feed
45·16 = 720 mL = 0.72 L
0.72·68 = 48.96 g/day
Shortfall
ΔP = 84 − 48.96 = 35.04 ≈ 35 g/day
Answer
ΔP = 35 g/day
10.Enteral & parenteral nutrition calculations
Answer: E = 2100 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 = 150/1.82² = 45.28 kg/m²
Energy goal
BMI 30–50: kcal per kg of actual body weight.
E = 14·150 = 2100 kcal/day
Answer
E = 2100 kcal/day
11.ECG rhythm strip interpretation
Answer: atrial rate = 250 bpm
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.
Flutter waves
F–F = 6 small boxes = 0.24 s → 1500 ÷ 6 = 250 per minute
QRS complexes
R–R = 24 small boxes = 0.96 s → 1500 ÷ 24 = 63 per minute
conduction ratio = 250 ÷ 63 = 4:1
Answer
atrial rate = 250 bpm
12.ECG rhythm strip interpretation
Answer: second-degree AV block type II
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.
Five steps
1. Rate: 7 QRS complexes in 6 s, × 10 = 70 per minute.
2. Rhythm: the P waves are regular; R–R is regular except for a long pause where a QRS is missing.
3. P waves: upright and regular (P–P 0.72 s, 83 per minute); one P in every 4 is not followed by a QRS.
4. PR interval: constant at 0.18 s in the conducted beats.
5. QRS: 0.08 s, narrow (below 0.12 s).
Interpretation
second-degree AV block type II
Answer
second-degree AV block type II
Type II and third-degree blocks are the ones that can suddenly progress, so textbooks rank them as more serious than type I.
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: D · A patient with a long-standing tracheostomy who needs routine suctioning and care
Why this is the answer
Routine tracheostomy care for a stable, long-term patient fits the LPN/LVN role in most settings. Fresh or bleeding tracheostomies, new admissions and titrated IV drugs need RN assessment.
Answer
D · A patient with a long-standing tracheostomy who needs routine suctioning and care
15.Infection control & patient safety
Answer: D · Not give it, and contact the prescriber, because it is never given by IV push
Why this is the answer
Potassium chloride given by IV push can cause fatal cardiac arrhythmias and arrest. It is only given diluted by controlled infusion, so the nurse does not give it and contacts the prescriber.
Answer
D · Not give it, and contact the prescriber, because it is never given by IV push
16.Infection control & patient safety
Answer: C · 1,400/mm3
Why this is the answer
ANC = 4,000 × (0.30 + 0.05) = 1,400/mm3. This is below normal (neutropenia), so the patient has a raised risk of infection.
Answer
C · 1,400/mm3
17.Lab values & electrolytes
Answer: A · Fatigue, pallor, a fast heart rate and breathlessness on exertion
Why this is the answer
Anemia reduces oxygen delivery. The heart beats faster to compensate, and the patient feels tired and breathless with activity and looks pale. Severe anemia can cause chest pain in people with heart disease.Checked against:Anemia · MedlinePlus (NIH) (2026)
Answer
A · Fatigue, pallor, a fast heart rate and breathlessness on exertion
18.Lab values & electrolytes
Answer: B · Cortisol is being produced without normal feedback control
Why this is the answer
Dexamethasone normally suppresses ACTH and lowers morning cortisol. Failure to suppress suggests autonomous cortisol excess (Cushing syndrome). Further tests then find the source, such as a pituitary or adrenal tumor.
Answer
B · Cortisol is being produced without normal feedback control