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
When may a nurse share confidential information without the patient's consent?
AWhen a colleague on another ward is curious
BWhen a journalist asks about a famous patient
CWhenever a relative asks for it
DWhen it is needed to protect someone from a risk of serious harm
2.Nursing fundamentalsHard
A patient with dementia keeps getting out of bed at night. What is the best first nursing approach?
ALook for an unmet need such as toileting, pain, hunger or thirst
BAsk the doctor to prescribe a sedative so the patient sleeps through the night
CTie a sheet across the bed to keep the patient in
DRaise the bed rails and leave the patient alone
3.Clinical nursingMedium
A patient has lost more than 10% of their body weight without trying over the last few months and has a low BMI. What is the most appropriate action?
ARestrict fluids to encourage appetite and give a low-protein diet instead
BWeigh the patient again in six months and review at that point
CEncourage a low-calorie diet
DRefer to the dietitian and start a nutrition care plan with food charts
4.Clinical nursingHard
A patient who has had a kidney stone is taught about prevention. Which statement shows a need for further teaching?
A"I will try to pass pale urine."
B"I will follow the diet advice for my stone type."
C"I will drink less water so I don't need to pass urine as often."
D"I will aim to drink plenty of fluids spread through every day."
5.Arterial blood gas interpretationMedium
A practice gas shows a metabolic acidosis with HCO₃⁻ 12 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.
HCO₃⁻ 12 mmol/L
PaCO₂ = mmHg
6.Arterial blood gas interpretationHard
A practice gas shows pH 7.29, PaCO₂ 30 mmHg (4.0 kPa) and HCO₃⁻ 14 mmol/L, with Na⁺ 144 and Cl⁻ 112 mmol/L. Use the anion gap and the delta ratio to click the best interpretation.
Practice exercise (made-up values, not clinical guidance). A practice patient is assessed with the Braden scale: sensory perception: slightly limited; moisture: very moist; activity: walks frequently; 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 107 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). Use the Devine formula to find the ideal body weight IBW of a woman who is 170 cm tall (1 in = 2.54 cm). Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). A critically ill woman is 163 cm tall and weighs 148 kg. The practice protocol gives 2 g of protein per kg of ideal body weight (Devine) per day if the BMI is 30 to under 40 kg/m², and 2.5 g/kg of ideal body weight per day if the BMI is 40 kg/m² or more. Find the protein goal P in g/day. Round to the nearest whole number.
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 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
2first-degree AV block
3second-degree AV block type I (Wenckebach)
4second-degree AV block type II
13.Prioritization & delegationMedium
A nurse sees a nursing assistant leave a confused patient’s bed in the highest position after care. What should the nurse do?
ALeave it because the patient is asleep
BWrite it in the assistant’s yearly review only
CAsk the family to lower the bed when they next visit
DLower the bed now and remind the assistant why it matters
14.Prioritization & delegationHard
During a busy shift, four tasks are due. Which should the nurse do first?
AFirst dose of IV antibiotic for a patient with suspected sepsis
BHelp a stable patient fill in tomorrow’s menu card
CGive a routine daily vitamin tablet that is due at the same time
DUpdate the nursing care plan before the managers’ audit
15.Infection control & patient safetyMedium
Which kitchen practice helps prevent scald burns in young children?
ALet the child stand on a chair beside the stove
BLeave hot drinks at the edge of the table
CTurn pot handles toward the back of the stove
DHold the child while drinking a hot drink
16.Infection control & patient safetyHard
In a US hospital (CMS rules), a patient keeps pulling at an endotracheal tube, and alternatives have failed. The nurse applies wrist restraints in an emergency. What must happen next?
AAsk the provider for a PRN restraint order to use as needed
BObtain a time-limited order for the restraint promptly, following policy
CKeep the restraints on without an order until the patient is calm
DAsk the family to sign a consent form instead of an order
17.Lab values & electrolytesMedium
A patient's potassium is 7.0 mEq/L. Which ECG change would the nurse expect?
AProminent U waves
BDelta waves before the QRS
CFlattened T waves
DTall, peaked T waves
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?
AMeasuring and recording intake and output
BDeciding when to recheck the sodium level
CTeaching the reasons for fluid restriction
DAssessing the patient for new confusion
3Solutions
1.Nursing fundamentals
Answer: D · When it is needed to protect someone from a risk of serious harm
Why this is the answer
Confidentiality can be broken without consent when required by law or when there is a serious risk of harm to the patient or others. Only the necessary information is shared, with the right people.
Answer
D · When it is needed to protect someone from a risk of serious harm
2.Nursing fundamentals
Answer: A · Look for an unmet need such as toileting, pain, hunger or thirst
Why this is the answer
Restlessness in dementia often has a cause, such as needing the toilet, pain or being cold. Meeting the need is safer than restraint or sedation, which increase the risk of harm.
Answer
A · Look for an unmet need such as toileting, pain, hunger or thirst
3.Clinical nursing
Answer: D · Refer to the dietitian and start a nutrition care plan with food charts
Why this is the answer
Large unplanned weight loss with a low BMI means high malnutrition risk. Management includes dietitian referral, food and fluid charts, support with eating and regular weighing.
Answer
D · Refer to the dietitian and start a nutrition care plan with food charts
4.Clinical nursing
Answer: C · "I will drink less water so I don't need to pass urine as often."
Why this is the answer
A high fluid intake dilutes urine and is the most important general measure to prevent stones. Dietary advice depends on the stone's composition.
Answer
C · "I will drink less water so I don't need to pass urine as often."
5.Arterial blood gas interpretation
Answer: PaCO₂ = 26 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.
Winter’s formula
PaCO₂ = 1.5·12 + 8 = 26 mmHg
range: 24–28 mmHg
Answer
PaCO₂ = 26 mmHg
6.Arterial blood gas interpretation
Answer: added normal-gap acidosis
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 = 144 − (112 + 14) = 18
Delta ratio
(18 − 12)/(24 − 14) = 0.6
added normal-gap acidosis
Answer
added normal-gap acidosis
7.Clinical assessment scores
Answer: B = 17
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: slightly limited → 3
moisture: very moist → 2
activity: walks frequently → 4
mobility: very limited → 2
nutrition: adequate → 3
friction and shear: no apparent problem → 3
Add
Braden total = 3 + 2 + 4 + 2 + 3 + 3 = 17
Answer
B = 17
8.Clinical assessment scores
Answer: DBP = 44 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 − 107)/2 = 88/2 = 44 mmHg
Answer
DBP = 44 mmHg
9.Enteral & parenteral nutrition calculations
Answer: IBW = 61.4 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
170 cm/2.54 = 66.93 in
Ideal body weight (Devine)
IBW = 45.5 + 2.3·(66.93 − 60) = 61.44 ≈ 61.4 kg
Answer
IBW = 61.4 kg
10.Enteral & parenteral nutrition calculations
Answer: P = 138 g/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). The protein goal is 2 g/kg of ideal body weight per day for BMI 30–40 and up to 2.5 g/kg of ideal body weight per day for BMI 40 and above. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Body mass index
BMI = 148/1.63² = 55.7 kg/m²
Ideal body weight (Devine)
163 cm/2.54 = 64.17 in
IBW = 45.5 + 2.3·(64.17 − 60) = 55.1 kg
Protein goal
BMI 40 or more: 2.5 g per kg of ideal body weight.
P = 2.5·55.1 = 137.7 ≈ 138 g/day
Answer
P = 138 g/day
11.ECG rhythm strip interpretation
Answer: QTc = 0.471 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 = 10 × 0.04 = 0.40 s
RR = 18 × 0.04 = 0.72 s
Bazett’s formula
QTc = 0.40/√0.72 = 0.40/0.8485 = 0.471 s
Answer
QTc = 0.471 s
Above the usual limits for both men (about 0.45 s) and women (about 0.46 s): prolonged. (471 ms)
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: 5 QRS complexes in 6 s, × 10 = 50 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 0.88 s, 68 per minute); one P in every 4 is not followed by a QRS.
4. PR interval: lengthens 0.18 → 0.32 → 0.38 s, then a P wave is not conducted.
5. QRS: 0.08 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: D · Lower the bed now and remind the assistant why it matters
Why this is the answer
A high bed increases the risk of a serious fall, so the nurse corrects it at once and gives brief, clear feedback. Leaving it or delaying feedback leaves the patient at risk.
Answer
D · Lower the bed now and remind the assistant why it matters
14.Prioritization & delegation
Answer: A · First dose of IV antibiotic for a patient with suspected sepsis
Why this is the answer
Early antibiotics improve survival in sepsis and are ideally given within an hour of recognition. The other tasks are routine and can wait.
Answer
A · First dose of IV antibiotic for a patient with suspected sepsis
15.Infection control & patient safety
Answer: C · Turn pot handles toward the back of the stove
Why this is the answer
Scalds from hot liquids are common childhood burns. Turning pot handles inward, using back burners and keeping hot drinks out of reach reduce the risk.
Answer
C · Turn pot handles toward the back of the stove
16.Infection control & patient safety
Answer: B · Obtain a time-limited order for the restraint promptly, following policy
Why this is the answer
Under US CMS rules, a nurse may apply a restraint first in an emergency, but an order from a licensed provider must be obtained promptly according to policy. PRN restraint orders are not allowed, and family consent does not replace an order. Other countries use different legal frameworks, but restraint is always a last resort that must be authorized, reviewed and documented.
Answer
B · Obtain a time-limited order for the restraint promptly, following policy
17.Lab values & electrolytes
Answer: D · Tall, peaked T waves
Why this is the answer
Hyperkalemia first causes tall, peaked T waves, then a prolonged PR interval, loss of P waves and a wide QRS, which can lead to ventricular fibrillation or asystole. U waves and flat T waves are signs of hypokalemia.
Answer
D · Tall, peaked T waves
18.Lab values & electrolytes
Answer: A · 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.