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 should a patient wash and dry their hands before a fingerprick glucose test?
AClean hands make the finger bleed more slowly
BSugar on the skin can give a falsely high reading
CWet hands give a falsely high reading
DIt is only needed if the hands look dirty
2.Nursing fundamentalsHard
A competent adult patient asks the nurse not to tell their family about their cancer diagnosis. What should the nurse do?
ATell the family, because relatives have a right to know about a serious diagnosis
BAsk the doctor to tell the family anyway
CTell the family only if they ask directly
DRespect the request and not share the information with the family
3.Clinical nursingMedium
Which measure helps reduce the risk of surgical site infection?
ARemoving hair, if needed, with clippers rather than a razor
BShaving the area with a razor the night before surgery
CLeaving the patient cool during surgery to slow bacterial growth
DChanging the wound dressing every hour
4.Clinical nursingHard
A patient has a swollen, warm, tender calf on one side. Which action should the nurse avoid?
AChecking whether VTE prophylaxis was given
BMassaging the calf
CMeasuring and comparing calf circumference
DReporting the findings to the doctor
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 144 mmol/L, glucose 23.7 mmol/L and urea 8.8 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 144 mmol/Lglucose 23.7 mmol/Lurea 8.8 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
Practice values: Na⁺ 138, Cl⁻ 110, HCO₃⁻ 13 mmol/L and albumin 23 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).
Practice exercise (made-up values, not clinical guidance). A practice chart records GCS 11, with E3 and V4. What motor score M was recorded, and which response does it describe? Give the number.
GCS 11E3V4
M =
8.Clinical assessment scoresHard
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: bedfast; mobility: very limited; nutrition: adequate; friction and shear: problem. Use the bands 19–23 not at risk, 15–18 mild, 13–14 moderate, 10–12 high and 9 or below very high. Click the risk level.
Practice exercise (made-up values, not clinical guidance). A 56 kg patient needs 1.5 g of protein per kg a day. The tube feed contains 55 g of protein per litre and runs at 50 mL/h for 18 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 72 kg adult receives 2400 mL of parenteral nutrition containing 17.5% dextrose, infused over 24 hours. Find the glucose infusion rate GIR in mg/kg/min. Round to two decimal places.
72 kg2400 mLdextrose 17.5%24 h
GIR = mg/kg/min
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
1first-degree AV block
2atrial fibrillation
3normal sinus rhythm
4junctional rhythm
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
1first-degree AV block
2third-degree (complete) AV block
3second-degree AV block type II
4second-degree AV block type I (Wenckebach)
13.Prioritization & delegationMedium
Using the Emergency Severity Index, which patient receives the highest acuity level?
AA patient with chest pain and normal vital signs
BA patient with a possible ankle fracture
CAn unresponsive patient with gasping, irregular breaths
DA patient with a sore throat for three days and normal vital signs
14.Prioritization & delegationHard
A patient with a head injury has a pupil on one side that is now large and does not react to light. What should the nurse do?
ADim the room lights so the pupil can get smaller
BReport it at once, as it may mean the brain is being compressed
CRecheck it at the next routine observation in four hours
DDocument it, because pupils often differ slightly after a head injury
15.Infection control & patient safetyMedium
Which patient has the highest risk of a burn from a heating pad?
AA patient recovering from a cold
BA patient with a sprained wrist who is fully alert
CA patient with diabetic peripheral neuropathy
DA healthy young adult with a strained muscle
16.Infection control & patient safetyHard
A patient is on contact precautions. Which task is appropriate for the nurse to delegate to assistive personnel?
AHelping the patient bathe while wearing a gown and gloves
BTeaching the family how to follow the precautions
CDeciding when the precautions can be stopped
DAssessing the wound for new signs of infection during the bath
17.Lab values & electrolytesMedium
A patient with hyperkalemia received IV regular insulin with dextrose. Which result must the nurse monitor closely over the next hours?
AHemoglobin, because insulin causes red cell loss
BSerum calcium, because it falls sharply
CSerum sodium, because it rises quickly
DBlood glucose, because hypoglycemia can occur
18.Lab values & electrolytesHard
A patient with blood pressure that is hard to control has a potassium of 2.9 mEq/L, a sodium of 144 mEq/L and a raised serum bicarbonate, without taking a diuretic. Which condition is most likely?
ACentral diabetes insipidus
BPrimary adrenal insufficiency
CPrimary hyperaldosteronism
DSyndrome of inappropriate ADH
3Solutions
1.Nursing fundamentals
Answer: B · Sugar on the skin can give a falsely high reading
Why this is the answer
Traces of food or drink on the finger can raise the reading. Washing with water and drying fully gives an accurate result; alcohol wipes can also affect some meters.
Answer
B · Sugar on the skin can give a falsely high reading
2.Nursing fundamentals
Answer: D · Respect the request and not share the information with the family
Why this is the answer
A patient with capacity decides who may receive their health information. The nurse can explore the patient's reasons and offer support, but must respect the wish.
Answer
D · Respect the request and not share the information with the family
3.Clinical nursing
Answer: A · Removing hair, if needed, with clippers rather than a razor
Why this is the answer
Razors cause micro-abrasions that increase infection risk, so hair is removed only if necessary with clippers just before surgery. Keeping patients warm and good skin preparation also help.
Answer
A · Removing hair, if needed, with clippers rather than a razor
4.Clinical nursing
Answer: B · Massaging the calf
Why this is the answer
Unilateral calf swelling and tenderness suggests DVT. Massaging the leg is avoided in case it dislodges the clot; the patient needs medical review and investigation.
Answer
B · Massaging the calf
5.Arterial blood gas interpretation
Answer: Osm = 321 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 = 2·144 + 23.7 + 8.8 = 320.5 ≈ 321 mOsm/kg
Answer
Osm = 321 mOsm/kg
6.Arterial blood gas interpretation
Answer: AGc = 19.25 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.
Anion gap
AG = 138 − (110 + 13) = 15
Correction for albumin
15 + 0.25·(40 − 23) = 19.25 mmol/L
Answer
AGc = 19.25 mmol/L
Above about 12 after correction: a high anion gap.
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 = 11 − 3 − 4 = 4
M4: withdraws the limb from pressure (normal flexion)
Answer
M = 4
8.Clinical assessment scores
Answer: high risk
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: bedfast → 1
mobility: very limited → 2
nutrition: adequate → 3
friction and shear: problem → 1
Add
Braden total = 1 + 3 + 1 + 2 + 3 + 1 = 11
Risk level
11 → high risk
Answer
high risk
9.Enteral & parenteral nutrition calculations
Answer: ΔP = 34.5 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
1.5·56 = 84 g/day
Protein from the feed
50·18 = 900 mL = 0.9 L
0.9·55 = 49.5 g/day
Shortfall
ΔP = 84 − 49.5 = 34.5 g/day
Answer
ΔP = 34.5 g/day
10.Enteral & parenteral nutrition calculations
Answer: GIR = 4.05 mg/kg/min
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.
Dextrose in the bag
17.5·2400/100 = 420 g = 420 000 mg
Minutes of infusion
24·60 = 1440 min
Glucose infusion rate
GIR = 420 000/(72·1440) = 4.051 ≈ 4.05 mg/kg/min
Answer
GIR = 4.05 mg/kg/min
11.ECG rhythm strip interpretation
Answer: junctional rhythm
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 = 31 small boxes, 1500 ÷ 31 ≈ 48 per minute.
2. Rhythm: regular, every R–R is 1.24 s.
3. P waves: inverted, just after each QRS.
4. PR interval: not measurable.
5. QRS: 0.06 s, narrow (below 0.12 s).
Interpretation
junctional rhythm
Answer
junctional rhythm
12.ECG rhythm strip interpretation
Answer: third-degree (complete) AV block
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: R–R = 36 small boxes, 1500 ÷ 36 ≈ 42 per minute.
2. Rhythm: R–R regular (1.44 s) and P–P regular (0.84 s), but the two are independent.
3. P waves: upright and regular at 71 per minute, but not linked to the QRS complexes; some hide in a QRS or a T wave.
4. PR interval: varies from beat to beat; there is no fixed relation.
5. QRS: 0.10 s, narrow (below 0.12 s).
Interpretation
third-degree (complete) AV block
Answer
third-degree (complete) AV block
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: C · An unresponsive patient with gasping, irregular breaths
Why this is the answer
An unresponsive patient with agonal breathing needs immediate airway and breathing support, which is ESI level 1. Chest pain with normal vital signs is high risk (level 2), and the others are lower levels.
Answer
C · An unresponsive patient with gasping, irregular breaths
14.Prioritization & delegation
Answer: B · Report it at once, as it may mean the brain is being compressed
Why this is the answer
A newly fixed, dilated pupil suggests pressure on the third cranial nerve from rising intracranial pressure or a bleed. It is a neurological emergency that needs immediate escalation.
Answer
B · Report it at once, as it may mean the brain is being compressed
15.Infection control & patient safety
Answer: C · A patient with diabetic peripheral neuropathy
Why this is the answer
Reduced sensation, as in peripheral neuropathy, prevents a person from feeling heat damage. Patients with poor sensation, poor circulation or confusion need very close monitoring if heat is used at all.
Answer
C · A patient with diabetic peripheral neuropathy
16.Infection control & patient safety
Answer: A · Helping the patient bathe while wearing a gown and gloves
Why this is the answer
Assistive personnel can carry out routine care for a stable patient, using the correct PPE. Assessment, teaching and clinical judgement, such as deciding when to stop precautions, cannot be delegated to them.
Answer
A · Helping the patient bathe while wearing a gown and gloves
17.Lab values & electrolytes
Answer: D · Blood glucose, because hypoglycemia can occur
Why this is the answer
Insulin shifts potassium into cells but also lowers glucose, and hypoglycemia can occur hours later, especially in kidney failure. Glucose is checked frequently, and potassium is rechecked, as the effect lasts only a few hours.
Answer
D · Blood glucose, because hypoglycemia can occur
18.Lab values & electrolytes
Answer: C · Primary hyperaldosteronism
Why this is the answer
Excess aldosterone causes sodium and water retention (hypertension), potassium loss (hypokalemia) and hydrogen ion loss (metabolic alkalosis). Adrenal insufficiency causes the opposite pattern, with low sodium and high potassium.