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 is getting up for the first time after several days in bed. What should the nurse do first?
AHelp the patient stand up quickly, so that the dizziness has less time to start
BHave the patient sit on the edge of the bed for a short time before standing
CAsk the patient to walk to the bathroom alone
DGive the patient a large drink of water while standing
2.Nursing fundamentalsHard
In English law, giving a treatment to a competent adult who has clearly refused it may amount to:
ADefamation of character
BBreach of an employment contract
CBattery (trespass to the person)
DTheft
3.Clinical nursingMedium
Which type of painkiller should a patient with liver cirrhosis usually avoid?
AHot packs applied to a painful joint
BNon-steroidal anti-inflammatory drugs such as ibuprofen
CLocal anaesthetic creams
DParacetamol (acetaminophen), given in a carefully reduced and monitored dose
4.Clinical nursingHard
A patient faints during cannulation, with a slow pulse and pallor, and recovers quickly when laid flat. There is no rash, wheeze or swelling. What is most likely?
AA hypoglycaemic coma
BVasovagal syncope
CA stroke
DAnaphylaxis
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 69 mmHg (9.2 kPa). Use the rule that in chronic respiratory acidosis HCO₃⁻ rises by 3.5 mmol/L for every 10 mmHg that PaCO₂ is above 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.
A practice gas shows a metabolic alkalosis with HCO₃⁻ 45 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 45 mmol/L
PaCO₂ = mmHg
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice patient is assessed with the Braden scale: sensory perception: completely limited; moisture: occasionally moist; activity: walks occasionally; mobility: very limited; nutrition: adequate; friction and shear: no apparent problem. Find the Braden total B.
6–23
B =
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 99 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 67 kg patient has a fluid goal of 30 mL/kg/day and receives all fluid through a feeding tube. The formula is 70% free water and runs at 50 mL/h for 18 hours a day. The rest of the fluid is given as water flushes every 4 hours. What volume V is each flush? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1000 mL of parenteral nutrition with final concentrations of 10% dextrose and 4.25% amino acids, plus 250 mL of 10% lipid emulsion (1.1 kcal/mL). Find the non-protein energy NPC in kcal per day. Round to the nearest whole number.
1000 mLdextrose 10%amino acids 4.25%lipid 250 mL · 1.1 kcal/mL
NPC = 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
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
1atrial fibrillation
2second-degree AV block type II
3second-degree AV block type I (Wenckebach)
4third-degree (complete) AV block
13.Prioritization & delegationMedium
Which scheduled medication is the most time-critical?
ARapid-acting insulin due with a breakfast tray that has arrived
BA daily multivitamin tablet due at 08:00
CA daily stool softener due with breakfast
DA daily cholesterol-lowering statin tablet due with breakfast at 08:00
14.Prioritization & delegationHard
An older patient has bruises of different ages and seems frightened when a relative visits. What is the nurse’s priority?
AIgnore it, because older people bruise easily
BAsk the relative directly in front of the patient whether they hit her
CEnsure the patient’s safety, document the findings and report as required
DTell the patient she must leave home and go to live somewhere else
15.Infection control & patient safetyMedium
After teaching a patient about a new medication, how does the nurse best check understanding?
AAsk “Do you understand?” and accept a yes
BAsk the family whether they understood the teaching
CAsk the patient to explain in their own words how and when to take it
DGive a printed leaflet about the drug and assume the patient will read it at home
16.Infection control & patient safetyHard
Ten minutes into a red blood cell transfusion, the patient reports chills and low back pain and has a new fever. What should the nurse do first?
AGive an antipyretic and continue the transfusion
BSlow the transfusion and recheck vital signs in 15 minutes
CStop the transfusion
DCall the blood bank and let the transfusion continue
17.Lab values & electrolytesMedium
A patient has started parenteral nutrition (PN) through a central line. Which test is monitored most frequently in the first days?
ABlood glucose
BSerum lipase
CThyroid hormones
DHemoglobin A1c
18.Lab values & electrolytesHard
A patient with SIADH is on fluid restriction. Which task can the RN delegate to unlicensed assistive personnel (UAP), such as a nursing or healthcare assistant?
ATeaching the reasons for fluid restriction
BDeciding when to recheck the sodium level
CAssessing the patient for new confusion
DMeasuring and recording intake and output
3Solutions
1.Nursing fundamentals
Answer: B · Have the patient sit on the edge of the bed for a short time before standing
Why this is the answer
After bed rest blood pressure may drop on standing. Sitting on the edge of the bed first, with the feet on the floor, lets the body adjust and lowers the risk of fainting and falls.
Answer
B · Have the patient sit on the edge of the bed for a short time before standing
2.Nursing fundamentals
Answer: C · Battery (trespass to the person)
Why this is the answer
Touching or treating a person without valid consent can be battery, even if the treatment was meant to help. This is why consent is needed before care.
Answer
C · Battery (trespass to the person)
3.Clinical nursing
Answer: B · Non-steroidal anti-inflammatory drugs such as ibuprofen
Why this is the answer
NSAIDs increase the risk of GI bleeding and can trigger kidney failure and fluid retention in cirrhosis. Paracetamol is usually preferred at a lower, carefully chosen dose.
Answer
B · Non-steroidal anti-inflammatory drugs such as ibuprofen
4.Clinical nursing
Answer: B · Vasovagal syncope
Why this is the answer
Vasovagal syncope is a reflex drop in heart rate and blood pressure triggered by pain, fear or needles. Anaphylaxis would usually include skin, airway or breathing features and a fast pulse.
Answer
B · Vasovagal syncope
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 34.15 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
|69 − 40| = 29 mmHg → 2.9 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 3.5·2.9 = 34.15 mmol/L
Answer
HCO₃⁻ = 34.15 mmol/L
6.Arterial blood gas interpretation
Answer: PaCO₂ = 52.5 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
0.7·45 + 21 = 52.5 mmHg
Answer
PaCO₂ = 52.5 mmHg
The rise has a limit: PaCO₂ rarely goes above about 55 mmHg from compensation alone.
7.Clinical assessment scores
Answer: B = 15
Braden scale: six subscales for pressure-injury risk. Sensory perception, moisture, activity, mobility and nutrition score 1 to 4, from the worst level (1) to no problem (4); friction and shear scores 1 to 3. The total runs from 6 to 23, and a lower total means a higher risk. Common bands: 19–23 not at risk, 15–18 mild risk, 13–14 moderate risk, 10–12 high risk and 9 or below very high risk.
Score each subscale
sensory perception: completely limited → 1
moisture: occasionally moist → 3
activity: walks occasionally → 3
mobility: very limited → 2
nutrition: adequate → 3
friction and shear: no apparent problem → 3
Add
Braden total = 1 + 3 + 3 + 2 + 3 + 3 = 15
Answer
B = 15
8.Clinical assessment scores
Answer: DBP = 48 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 − 99)/2 = 96/2 = 48 mmHg
Answer
DBP = 48 mmHg
9.Enteral & parenteral nutrition calculations
Answer: V = 230 mL
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.
Fluid goal
30·67 = 2010 mL/day
Free water from the formula
50·18 = 900 mL
900·0.7 = 630 mL
Water still needed
2010 − 630 = 1380 mL/day
Volume per flush
24/4 = 6 flushes
V = 1380/6 = 230 mL
Answer
V = 230 mL
10.Enteral & parenteral nutrition calculations
Answer: NPC = 615 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: 10·1000/100 = 100 g
amino acids: 4.25·1000/100 = 42.5 g
Kilocalories per component
dextrose: 100·3.4 = 340 kcal
amino acids: 42.5·4 = 170 kcal
lipid: 250·1.1 = 275 kcal
Non-protein energy
NPC = 340 + 275 = 615 kcal/day
Answer
NPC = 615 kcal/day
11.ECG rhythm strip interpretation
Answer: pause = 1.44 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
36 small boxes from R to R across the pause
Convert
pause = 36 × 0.04 s = 1.44 s
Compare with P–P
1.44 ÷ 0.88 ≈ 1.6 P–P cycles, not a whole number
Answer
pause = 1.44 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: second-degree AV block type I (Wenckebach)
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: 4 QRS complexes in 6 s, × 10 = 40 per minute.
2. Rhythm: regularly irregular, the QRS complexes come in groups separated by a pause (group beating).
3. P waves: upright and regular (P–P 0.92 s, 65 per minute); one P in every 3 is not followed by a QRS.
4. PR interval: lengthens 0.18 → 0.30 s, then a P wave is not conducted.
5. QRS: 0.10 s, narrow (below 0.12 s).
Interpretation
second-degree AV block type I (Wenckebach)
Answer
second-degree AV block type I (Wenckebach)
13.Prioritization & delegation
Answer: A · Rapid-acting insulin due with a breakfast tray that has arrived
Why this is the answer
Rapid-acting insulin is given with a meal; giving it late or without food can cause high or low blood glucose. The other daily medicines can be given a little later without harm.
Answer
A · Rapid-acting insulin due with a breakfast tray that has arrived
14.Prioritization & delegation
Answer: C · Ensure the patient’s safety, document the findings and report as required
Why this is the answer
Unexplained bruises of different ages and fear of a carer can suggest abuse. The nurse makes sure the patient is safe, documents objectively and reports according to law and policy.
Answer
C · Ensure the patient’s safety, document the findings and report as required
15.Infection control & patient safety
Answer: C · Ask the patient to explain in their own words how and when to take it
Why this is the answer
With teach-back, the patient explains the information in their own words, which shows whether the teaching worked. A yes to “Do you understand?” does not confirm understanding.
Answer
C · Ask the patient to explain in their own words how and when to take it
16.Infection control & patient safety
Answer: C · Stop the transfusion
Why this is the answer
These signs suggest an acute transfusion reaction, possibly hemolytic. The nurse stops the transfusion at once, keeps the IV open with normal saline through new tubing, assesses the patient and notifies the provider and blood bank.
Answer
C · Stop the transfusion
17.Lab values & electrolytes
Answer: A · Blood glucose
Why this is the answer
PN contains concentrated dextrose, so hyperglycemia is common, especially at the start; glucose is checked frequently and insulin may be needed. Electrolytes, including phosphate, magnesium and potassium, are also monitored for refeeding syndrome.
Answer
A · Blood glucose
18.Lab values & electrolytes
Answer: D · Measuring and recording intake and output
Why this is the answer
UAP can measure and record intake and output and weigh the patient, then report the values to the RN. Assessing mental status, teaching and making decisions about laboratory monitoring need nursing judgment and remain with the RN.