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
How should a liquid medicine be measured in a medicine cup?
AAt eye level, reading the lowest point of the curved surface
BFrom above, reading the highest point at the edge of the liquid
CBy pouring until it looks about right
DBy filling the cup to the very top
2.Nursing fundamentalsHard
A patient describes burning, shooting pain with pins and needles in both feet. Which type of pain is most likely?
AAcute somatic pain
BNeuropathic pain
CVisceral pain
DReferred pain
3.Clinical nursingMedium
Which instruction is correct for taking weekly alendronic acid (alendronate)?
AChew the tablet with breakfast and a cup of milky tea
BTake it with a glass of milk at bedtime and then lie down straight away
CTake it with plain water on an empty stomach and stay upright for 30 minutes
DTake it with an antacid to protect the stomach
4.Clinical nursingHard
A patient has new facial weakness. Which feature suggests a stroke rather than Bell's palsy?
AThe patient has had a recent cold
BThe patient has pain behind the ear
CThe whole of one side of the face, including the forehead, is weak
DThe forehead can still be wrinkled on the affected side
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 60 mmHg (8.0 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 exercise (made-up values, not clinical guidance). A practice chart records GCS 5, with E2 and V2. What motor score M was recorded, and which response does it describe? Give the number.
GCS 5E2V2
M =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 22/min, SpO₂ 92% on supplemental oxygen, blood pressure 150/90 mmHg, pulse 82/min, alert, temperature 36.8 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). A 68 kg patient has a fluid goal of 30 mL/kg/day and receives all fluid through a feeding tube. The formula is 76% free water and runs at 75 mL/h for 20 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). A child who weighs 10 kg receives 7.5% dextrose at 55 mL/h. Find the glucose infusion rate GIR in mg/kg/min. Round to two decimal places.
10 kg7.5%55 mL/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
2sinus tachycardia
3sinus bradycardia
4junctional rhythm
12.ECG rhythm strip interpretationHard
This patient has a pacemaker. Interpret the lead II strip. 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
1paced rhythm, failure to capture
2idioventricular rhythm
3dual-chamber (AV) paced rhythm
4third-degree (complete) AV block
13.Prioritization & delegationMedium
When making patient assignments, what should the charge nurse consider first?
AMatching each patient’s needs to staff competence
BGiving each nurse patients in rooms next to each other
CLetting staff choose the patients they prefer
DGiving the newest staff the most complex patients
14.Prioritization & delegationHard
A patient is receiving IV potassium chloride through a peripheral line and complains of burning at the site, which looks red. What does the nurse do first?
AApply a warm pack and continue the infusion
BStop the infusion and assess the IV site
CTell the patient that burning is expected and continue
DIncrease the infusion rate to finish the dose sooner
15.Infection control & patient safetyMedium
A parent calls because a toddler has swallowed some household cleaner. The child is awake and breathing normally. What should the nurse advise first?
AWait to see whether any symptoms develop over the next day
BMake the child vomit, using a finger at the back of the throat
CGive syrup of ipecac from the medicine cabinet
DContact the local poison advice service now for specific advice
16.Infection control & patient safetyHard
A patient is admitted with acute diarrhea, and C. difficile is suspected. The test result is pending. When should contact precautions start?
AStraight away, without waiting for the test result
BAfter three days of diarrhea
COnly if the patient develops a fever
DOnly when the test result comes back positive
17.Lab values & electrolytesMedium
A patient due for digoxin has a potassium of 3.1 mEq/L. Why is this result important?
ALow potassium increases the risk of digoxin toxicity
BPotassium and digoxin do not interact
CLow potassium makes digoxin ineffective, so the dose should be doubled
DLow potassium protects the heart from digoxin side effects
18.Lab values & electrolytesHard
A patient has painless jaundice, itching, dark urine and pale stools. ALP is markedly raised, conjugated (direct) bilirubin is high and ALT is only mildly raised. What is the most likely cause?
AAcute viral hepatitis with widespread liver cell damage
BGilbert syndrome, a harmless inherited bilirubin disorder
CIncreased breakdown of red blood cells (hemolytic anemia)
DBlockage of bile flow, for example by a tumor in the bile duct
3Solutions
1.Nursing fundamentals
Answer: A · At eye level, reading the lowest point of the curved surface
Why this is the answer
The cup is placed on a flat surface and read at eye level at the bottom of the meniscus. An oral syringe is more accurate for small volumes.
Answer
A · At eye level, reading the lowest point of the curved surface
2.Nursing fundamentals
Answer: B · Neuropathic pain
Why this is the answer
Neuropathic pain comes from damage to nerves, for example in diabetes, and is often burning, shooting or tingling. It may respond poorly to standard analgesics and need specific drugs.
Answer
B · Neuropathic pain
3.Clinical nursing
Answer: C · Take it with plain water on an empty stomach and stay upright for 30 minutes
Why this is the answer
Alendronic acid must be taken with plain water before food, and the patient must stay upright to reduce oesophageal irritation. Food, milk and antacids reduce absorption.
Answer
C · Take it with plain water on an empty stomach and stay upright for 30 minutes
4.Clinical nursing
Answer: D · The forehead can still be wrinkled on the affected side
Why this is the answer
In a stroke (upper motor neurone lesion), the forehead is usually spared because it has bilateral cortical supply. Bell's palsy (lower motor neurone) weakens the whole side, including the forehead.
Answer
D · The forehead can still be wrinkled on the affected side
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 31 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
|60 − 40| = 20 mmHg → 2 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 3.5·2 = 31 mmol/L
Answer
HCO₃⁻ = 31 mmol/L
6.Arterial blood gas interpretation
Answer: AGc = 20.5 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 = 135 − (104 + 13) = 18
Correction for albumin
18 + 0.25·(40 − 30) = 20.5 mmol/L
Answer
AGc = 20.5 mmol/L
Above about 12 after correction: a high anion gap.
7.Clinical assessment scores
Answer: M = 1
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 = 5 − 2 − 2 = 1
M1: no movement at all
Answer
M = 1
8.Clinical assessment scores
Answer: medium
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 22/min → 2
SpO₂ 92% → 2
on oxygen → 2
SBP 150 mmHg → 0
HR 82/min → 0
alert (A) → 0
T 36.8 °C → 0
Total and red scores
NEWS2 = 2 + 2 + 2 + 0 + 0 + 0 + 0 = 6
No parameter scores 3.
Risk group
medium
Answer
medium
A total of 5 or more calls for an urgent clinical response.
9.Enteral & parenteral nutrition calculations
Answer: V = 150 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
30·68 = 2040 mL/day
Free water from the formula
75·20 = 1500 mL
1500·0.76 = 1140 mL
Water still needed
2040 − 1140 = 900 mL/day
Volume per flush
24/4 = 6 flushes
V = 900/6 = 150 mL
Answer
V = 150 mL
10.Enteral & parenteral nutrition calculations
Answer: GIR = 6.88 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 concentration
7.5% = 75 mg/mL
Dextrose per minute
75·55/60 = 68.75 mg/min
Per kilogram
GIR = 68.75/10 = 6.875 ≈ 6.88 mg/kg/min
Answer
GIR = 6.88 mg/kg/min
Shortcut: GIR = % dextrose × mL/h/(6 × kg).
11.ECG rhythm strip interpretation
Answer: first-degree AV block
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 = 26 small boxes, 1500 ÷ 26 ≈ 58 per minute.
2. Rhythm: regular, every R–R is 1.04 s.
3. P waves: upright, one before every QRS, all alike.
4. PR interval: 0.24 s, constant, longer than 0.20 s.
5. QRS: 0.10 s, narrow (below 0.12 s).
Interpretation
first-degree AV block
Answer
first-degree AV block
12.ECG rhythm strip interpretation
Answer: dual-chamber (AV) paced rhythm
Paced rhythms: a pacemaker impulse shows as a narrow vertical pacing spike. After a ventricular spike the QRS is wide (0.12 s or more), because the impulse spreads from the lead through the muscle instead of the conduction system; with right-ventricular pacing it is often mostly negative in lead II. A spike before each P wave means atrial pacing, and a dual-chamber (AV) pacemaker shows an atrial spike and a P wave, then, after the programmed AV delay, a ventricular spike and a wide QRS. Capture means every spike is followed by a depolarisation. Failure to capture is a spike without a P wave or QRS after it; failure to sense (spikes that ignore the patient’s own beats) and failure to pace (no spike when one is due) are the other classic malfunctions.
Five steps
1. Rate: R–R = 22 small boxes, 1500 ÷ 22 ≈ 68 per minute.
2. Rhythm: regular, every R–R is 0.88 s.
3. P waves: each P wave follows its own pacing spike (atrial pacing).
4. AV interval: the second spike comes 0.16 s after the first one (the programmed AV delay).
5. QRS: 0.16 s, wide, right after the second spike (ventricular pacing).
Interpretation
dual-chamber (AV) paced rhythm
Answer
dual-chamber (AV) paced rhythm
The paced QRS is wide by nature; do not call it a bundle branch block or a ventricular rhythm.
13.Prioritization & delegation
Answer: A · Matching each patient’s needs to staff competence
Why this is the answer
Assignments are based mainly on patient acuity and needs and on each staff member’s skills and scope. Geography and continuity of care help, but they come after safety.
Answer
A · Matching each patient’s needs to staff competence
14.Prioritization & delegation
Answer: B · Stop the infusion and assess the IV site
Why this is the answer
Pain and redness suggest phlebitis or infiltration. The nurse stops the infusion, assesses the site and informs the provider. Continuing the infusion, or giving it faster, increases tissue damage.
Answer
B · Stop the infusion and assess the IV site
15.Infection control & patient safety
Answer: D · Contact the local poison advice service now for specific advice
Why this is the answer
A poison advice service (poison control in the US, or NHS 111 in the UK) can give advice for the exact product. Inducing vomiting is not recommended, because corrosive products can burn the esophagus again and vomit can be aspirated. Emergency services are called if the child has trouble breathing or is drowsy.
Answer
D · Contact the local poison advice service now for specific advice
16.Infection control & patient safety
Answer: A · Straight away, without waiting for the test result
Why this is the answer
Precautions start on suspicion, because the patient can spread spores while the test is pending. The patient is placed in a single room with contact precautions, and soap-and-water hand washing is used.
Answer
A · Straight away, without waiting for the test result
17.Lab values & electrolytes
Answer: A · Low potassium increases the risk of digoxin toxicity
Why this is the answer
Digoxin binds where potassium normally binds on the sodium–potassium pump, so a low potassium increases digoxin’s effect and the risk of arrhythmias. The nurse reports the value before giving the dose.
Answer
A · Low potassium increases the risk of digoxin toxicity
18.Lab values & electrolytes
Answer: D · Blockage of bile flow, for example by a tumor in the bile duct
Why this is the answer
In obstruction, conjugated bilirubin backs up into the blood and is passed in the urine, making it dark, while stools are pale and ALP rises. Hemolysis and Gilbert syndrome raise unconjugated bilirubin; hepatitis raises ALT much more.Checked against:Bilirubin in Urine · MedlinePlus (NIH) (2024)
Answer
D · Blockage of bile flow, for example by a tumor in the bile duct