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
What is tolerance to an opioid?
AA craving to take the drug for its mental effects
BNeeding a higher dose to get the same pain relief
CAn allergic reaction to the drug
DFeeling no side effects at all from the drug
2.Nursing fundamentalsHard
An older patient has unexplained bruises of different ages, and the carer always answers questions for them. What should the nurse do?
ADocument the findings and follow the local safeguarding procedure
BDiscuss it only with the patient's neighbours
CConfront the carer and accuse them of abuse
DIgnore it, because older people bruise easily and the carer seems attentive
3.Clinical nursingMedium
What does HbA1c measure?
AThe amount of ketones in the urine
BAverage blood glucose over roughly the previous two to three months
CBlood glucose at the moment of testing
DInsulin levels after a meal
4.Clinical nursingHard
A patient with a tracheostomy suddenly cannot breathe and the tube appears blocked. What is the first action?
AGive oxygen through the mouth only
BWait for the doctor before doing anything
CDeflate the cuff and leave the patient
DRemove the inner tube (cannula) and check whether it is blocked
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 49 mmHg (6.5 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⁻.
Practice values: Na⁺ 145, Cl⁻ 93 and HCO₃⁻ 14 mmol/L. Calculate the delta ratio (AG − 12)/(24 − HCO₃⁻), using AG = Na⁺ − (Cl⁻ + HCO₃⁻). Give two decimals.
Na⁺ 145 mmol/LCl⁻ 93 mmol/LHCO₃⁻ 14 mmol/L
delta ratio =
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: no; secondary diagnosis: no; ambulatory aid: none, bed rest or nurse assists; IV therapy or saline lock: no; gait: weak; mental status: overestimates or forgets limits. Find the Morse total MFS.
0–125
MFS =
8.Clinical assessment scoresHard
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: no; secondary diagnosis: yes; ambulatory aid: none, bed rest or nurse assists; IV therapy or saline lock: no; gait: weak; mental status: knows own limits. Using the cut-offs 0–24 low, 25–44 moderate and 45 or more high, click the fall-risk level.
Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a man who is 194 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 1200 mL of parenteral nutrition with final concentrations of 25% dextrose and 4.25% amino acids, plus 500 mL of 10% lipid emulsion (1.1 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
1200 mLdextrose 25%amino acids 4.25%lipid 500 mL · 1.1 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 Bazett’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
This lead II strip shows second-degree AV block type I (Wenckebach). Measure the PR interval of the last conducted beat before a non-conducted P wave (the longest PR), in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
longest PR = s
13.Prioritization & delegationMedium
A nurse teaches a patient with COPD pursed-lip breathing. Which statement shows a need for further teaching?
A“I will breathe in through my mouth and out quickly through my nose.”
B“I will breathe in slowly through my nose.”
C“I will breathe out slowly through pursed lips.”
D“I will make my breath out about twice as long as my breath in.”
14.Prioritization & delegationHard
A patient with a new tracheostomy is coughing, has noisy breathing and an SpO₂ that has fallen to 86%. What is the first action?
AChange the tracheostomy ties
BDocument the SpO₂ and recheck in 30 minutes
CGive a nebulized bronchodilator
DSuction the tracheostomy
15.Infection control & patient safetyMedium
A colleague has drawn up a medication and asks the nurse to give it to her patient. What should the nurse do?
ADecline, and give only medications that the nurse prepared or checked personally
BGive it, because the colleague is experienced
CGive it, and document that the colleague prepared it
DGive it, as long as the syringe has a label with the drug name on it
16.Infection control & patient safetyHard
A patient on airborne precautions needs an urgent CT scan. Which plan is correct?
APatient goes unmasked, and the CT room is cleaned the next day
BPatient masked, CT warned in advance, staff in respirators
CPatient wears an N95 respirator, so staff need no protection
DThe scan is postponed until the patient is no longer infectious
17.Lab values & electrolytesMedium
An older adult takes lisinopril and furosemide and recently started daily ibuprofen for knee pain. The creatinine has risen from 1.0 to 1.8 mg/dL (88 to 159 µmol/L). What is the most likely cause?
AThe NSAID reduces kidney blood flow on top of the other two drugs
BA laboratory error, since ibuprofen has no effect on the kidney
CMore activity has increased the patient's muscle mass quickly
DNormal aging of the kidneys over a period of a few weeks
18.Lab values & electrolytesHard
A patient on high-dose dexamethasone has a white cell count of 15 × 10³/µL, mostly mature neutrophils with no bands. They have no fever and no signs of infection. What is the most likely explanation?
AA steroid effect that moves neutrophils into the circulating blood
BCertain sepsis that needs antibiotics started without delay
CA new leukemia that is confirmed by this result alone
DA laboratory error, because steroids always lower the white count
3Solutions
1.Nursing fundamentals
Answer: B · Needing a higher dose to get the same pain relief
Why this is the answer
Tolerance is a physical adaptation in which the same dose has less effect over time. It is not the same as addiction, which involves craving and harmful use.
Answer
B · Needing a higher dose to get the same pain relief
2.Nursing fundamentals
Answer: A · Document the findings and follow the local safeguarding procedure
Why this is the answer
Bruises of different ages and a controlling carer can be signs of abuse. The nurse should speak to the patient alone if possible, document facts accurately and report through safeguarding procedures.
Answer
A · Document the findings and follow the local safeguarding procedure
3.Clinical nursing
Answer: B · Average blood glucose over roughly the previous two to three months
Why this is the answer
HbA1c reflects glycation of haemoglobin over the life of red cells, giving an estimate of long-term glucose control.
Answer
B · Average blood glucose over roughly the previous two to three months
4.Clinical nursing
Answer: D · Remove the inner tube (cannula) and check whether it is blocked
Why this is the answer
Following emergency algorithms, remove the inner cannula first, attempt suction and call for help. If that fails, further steps include cuff deflation and changing the tube.
Answer
D · Remove the inner tube (cannula) and check whether it is blocked
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 27.15 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
|49 − 40| = 9 mmHg → 0.9 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 3.5·0.9 = 27.15 mmol/L
Answer
HCO₃⁻ = 27.15 mmol/L
6.Arterial blood gas interpretation
Answer: delta ratio = 2.6
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 = 145 − (93 + 14) = 38
Delta ratio
(38 − 12)/(24 − 14) = 26/10 = 2.6
Answer
delta ratio = 2.6
Above 2: an added metabolic alkalosis.
7.Clinical assessment scores
Answer: MFS = 25
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: no → 0
secondary diagnosis: no → 0
ambulatory aid: none, bed rest or nurse assists → 0
IV therapy or saline lock: no → 0
gait: weak → 10
mental status: overestimates or forgets limits → 15
Add
Morse total = 0 + 0 + 0 + 0 + 10 + 15 = 25
Answer
MFS = 25
8.Clinical assessment scores
Answer: moderate risk
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: no → 0
secondary diagnosis: yes → 15
ambulatory aid: none, bed rest or nurse assists → 0
IV therapy or saline lock: no → 0
gait: weak → 10
mental status: knows own limits → 0
Add
Morse total = 0 + 15 + 0 + 0 + 10 + 0 = 25
Risk level
25 → moderate risk
Answer
moderate risk
9.Enteral & parenteral nutrition calculations
Answer: IBW = 87.7 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
194 cm/2.54 = 76.38 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(76.38 − 60) = 87.67 ≈ 87.7 kg
Answer
IBW = 87.7 kg
10.Enteral & parenteral nutrition calculations
Answer: E = 1774 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: 25·1200/100 = 300 g
amino acids: 4.25·1200/100 = 51 g
Kilocalories per component
dextrose: 300·3.4 = 1020 kcal
amino acids: 51·4 = 204 kcal
lipid: 500·1.1 = 550 kcal
Total energy
E = 1020 + 204 + 550 = 1774 kcal/day
Answer
E = 1774 kcal/day
11.ECG rhythm strip interpretation
Answer: QTc = 0.5 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 = 12 × 0.04 = 0.48 s
RR = 23 × 0.04 = 0.92 s
Bazett’s formula
QTc = 0.48/√0.92 = 0.48/0.9592 = 0.5 s
Answer
QTc = 0.5 s
Above the usual limits for both men (about 0.45 s) and women (about 0.46 s): prolonged. (500 ms)
12.ECG rhythm strip interpretation
Answer:longest PR = 0.4 s
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.
March out the P waves
P–P = 0.88 s, regular; one P wave in every 4 is not conducted
PR in each group
PR₁ = 0.20 s, PR₂ = 0.34 s, PR₃ = 0.40 s
Answer
longest PR = 0.4 s
The biggest step in PR comes between the first and second beats of a group; later steps are smaller, which is why the R–R intervals shorten before the pause.
13.Prioritization & delegation
Answer: A · “I will breathe in through my mouth and out quickly through my nose.”
Why this is the answer
Pursed-lip breathing means breathing in through the nose and out slowly through pursed lips, making exhalation longer. This keeps airways open and reduces air trapping.
Answer
A · “I will breathe in through my mouth and out quickly through my nose.”
14.Prioritization & delegation
Answer: D · Suction the tracheostomy
Why this is the answer
Noisy breathing, coughing and a falling SpO₂ in a patient with a tracheostomy suggest secretions in the tube. Suctioning clears the airway. If the airway is still blocked, follow the emergency tracheostomy algorithm and call for help.
Answer
D · Suction the tracheostomy
15.Infection control & patient safety
Answer: A · Decline, and give only medications that the nurse prepared or checked personally
Why this is the answer
Nurses give only medicines they prepared themselves or verified fully, because they are accountable for what they give. A drug prepared by someone else may be wrong in ways the nurse cannot see.
Answer
A · Decline, and give only medications that the nurse prepared or checked personally
16.Infection control & patient safety
Answer: B · Patient masked, CT warned in advance, staff in respirators
Why this is the answer
Urgent tests are not delayed, but the patient wears a surgical mask to contain particles, the route is planned, and the receiving staff are informed so they can protect themselves and other patients.
Answer
B · Patient masked, CT warned in advance, staff in respirators
17.Lab values & electrolytes
Answer: A · The NSAID reduces kidney blood flow on top of the other two drugs
Why this is the answer
NSAIDs reduce prostaglandin-driven blood flow to the kidney. Combined with an ACE inhibitor and a diuretic, this can cause acute kidney injury, especially in older adults. The nurse reports the result and the NSAID is usually stopped.
Answer
A · The NSAID reduces kidney blood flow on top of the other two drugs
18.Lab values & electrolytes
Answer: A · A steroid effect that moves neutrophils into the circulating blood
Why this is the answer
Corticosteroids raise the neutrophil count by releasing marginated neutrophils and slowing their exit from the blood, usually without a left shift. The nurse still assesses carefully, because steroids can also hide the usual signs of infection.
Answer
A · A steroid effect that moves neutrophils into the circulating blood