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 caller says they are a patient's daughter and asks for details of the patient's condition. What should the nurse do?
AHang up without saying anything
BGive full details, as close family members have a right to know
CRead out the latest notes over the phone
DCheck the patient's wishes and the caller's identity first
2.Nursing fundamentalsHard
A dying patient's breathing gets deeper and faster, then shallower, followed by a pause with no breathing, in a repeating cycle. What is this pattern called?
AParadoxical breathing
BBiot's breathing
CCheyne–Stokes breathing
DKussmaul breathing
3.Clinical nursingMedium
A patient with pneumonia is breathless and coughing up thick sputum. Which nursing measure helps most with breathing?
ARestricting all oral fluids
BDiscouraging coughing to save energy
CLying the patient flat so that they can rest and conserve energy
DSitting the patient upright and supporting them to clear secretions
4.Clinical nursingHard
A patient with a central venous catheter develops fever and rigors shortly after the line is flushed, with no other obvious source. What should be suspected?
AA catheter-related bloodstream infection
BA pulmonary embolism
CNormal response to line use
DAn allergic reaction to the saline flush
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 147 mmol/L, glucose 27.1 mmol/L and urea 14.2 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 147 mmol/Lglucose 27.1 mmol/Lurea 14.2 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
A practice gas shows a metabolic acidosis: pH 7.20, PaCO₂ 21 mmHg (2.8 kPa), HCO₃⁻ 8 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.
pH 7.20PaCO₂ 21 mmHg (2.8 kPa)HCO₃⁻ 8 mmol/L
1appropriate compensation
2added respiratory acidosis
3added respiratory alkalosis
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A patient has a pulse of 111/min and a blood pressure of 89/49 mmHg. Find the shock index SI = HR/SBP. Round to two decimal places.
HR 111/minBP 89/49 mmHg
SI =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). At 5 minutes after birth, a practice newborn has a pink body with blue hands and feet, a heart rate of 80/min, a grimace when stimulated, some flexion of the arms and legs and no breathing. Score the APGAR and click how the score is interpreted.
Practice exercise (made-up values, not clinical guidance). Use the Devine formula to find the ideal body weight IBW of a man who is 168 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 1800 mL of parenteral nutrition with final concentrations of 25% dextrose and 6% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the non-protein kilocalorie to nitrogen ratio NPC : N (the number x in x : 1). Round to the nearest whole number.
1800 mLdextrose 25%amino acids 6%lipid 250 mL · 2 kcal/mL
NPC : N =
11.ECG rhythm strip interpretationMedium
This lead II strip shows atrial flutter. Measure the flutter-wave interval and find the atrial rate in beats per minute.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
atrial rate = bpm
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
1idioventricular rhythm
2paced rhythm, failure to capture
3dual-chamber (AV) paced rhythm
4third-degree (complete) AV block
13.Prioritization & delegationMedium
A patient receives hemodialysis this morning. Which type of medication is often held before dialysis, as prescribed?
AEye drops for glaucoma
BInhaled bronchodilators
CAntihypertensive drugs
DTopical skin creams
14.Prioritization & delegationHard
A patient had sudden difficulty speaking 45 minutes ago. Which action has the highest priority?
AWait until the neurologist can assess the patient on the morning ward round
BActivate the stroke team for urgent imaging, noting when last known well
CGive water so the patient can take the usual morning medicines
DGive aspirin by mouth straight away to limit the clot
15.Infection control & patient safetyMedium
A patient is admitted to an inpatient mental health unit. Why are personal belongings checked?
ATo decide which family members may visit
BTo make a list of valuable items for insurance
CTo find out what the patient likes to wear during the hospital stay
DTo remove items that could be used to harm self or others
16.Infection control & patient safetyHard
A nurse teaches an older adult about preventing falls at home. Which statement shows a need for further teaching?
A“I keep small rugs in the hall so my feet stay warm.”
B“I had grab bars put in next to the toilet.”
C“I wear shoes with non-slip soles around the house.”
D“I use night lights between my bedroom and the bathroom.”
17.Lab values & electrolytesMedium
In the third trimester of pregnancy, a woman's alkaline phosphatase (ALP) is about twice the usual adult range, and the other liver tests are normal. What is the best interpretation?
AA sign of acute viral hepatitis
BA sign of new bone cancer
CA sign of blocked bile ducts
DA normal rise from placental ALP
18.Lab values & electrolytesHard
Which cerebrospinal fluid (CSF) pattern most strongly suggests bacterial meningitis?
ACloudy fluid, low glucose, high protein, many neutrophils
BClear fluid, high glucose, low protein, many red cells
CClear fluid, normal glucose, normal protein, no white cells
DClear fluid, normal glucose, mildly raised protein, lymphocytes
3Solutions
1.Nursing fundamentals
Answer: D · Check the patient's wishes and the caller's identity first
Why this is the answer
Information is shared only with people the patient has agreed to, and the caller's identity is checked as per policy. Often only limited information is given by phone.
Answer
D · Check the patient's wishes and the caller's identity first
2.Nursing fundamentals
Answer: C · Cheyne–Stokes breathing
Why this is the answer
Cheyne–Stokes breathing is a cyclical rise and fall in depth with periods of apnoea. It is common near the end of life and in severe heart failure or brain injury.
Answer
C · Cheyne–Stokes breathing
3.Clinical nursing
Answer: D · Sitting the patient upright and supporting them to clear secretions
Why this is the answer
An upright position improves lung expansion, and adequate fluids, deep breathing and coughing help clear sputum. Oxygen is given to target saturations if needed.
Answer
D · Sitting the patient upright and supporting them to clear secretions
4.Clinical nursing
Answer: A · A catheter-related bloodstream infection
Why this is the answer
Rigors after flushing suggest bacteria colonising the catheter. Blood cultures are taken (often from the line and a peripheral vein) and the team decides whether to remove the line.
Answer
A · A catheter-related bloodstream infection
5.Arterial blood gas interpretation
Answer: Osm = 335 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 = 2·147 + 27.1 + 14.2 = 335.3 ≈ 335 mOsm/kg
Answer
Osm = 335 mOsm/kg
6.Arterial blood gas interpretation
Answer: appropriate compensation
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
1.5·8 + 8 = 20 → 18–22 mmHg
Compare
measured: 21 mmHg → appropriate compensation
Answer
appropriate compensation
7.Clinical assessment scores
Answer: SI = 1.25
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.
Shock index
SI = 111/89 = 1.247 ≈ 1.25
Answer
SI = 1.25
1 or more: a warning sign of shock in this practice case.
8.Clinical assessment scores
Answer: moderately abnormal
APGAR score: five signs, each scored 0, 1 or 2, checked at 1 and 5 minutes after birth. Appearance (colour): blue or pale 0, pink body with blue extremities 1, pink all over 2. Pulse: absent 0, below 100/min 1, 100/min or more 2. Grimace (reflex irritability): none 0, grimace 1, cry, cough or sneeze 2. Activity (tone): limp 0, some flexion 1, active movement 2. Respiration: absent 0, slow or irregular with a weak cry 1, good with a strong cry 2. A total of 7–10 is reassuring, 4–6 moderately abnormal and 0–3 low.
Score each sign
Appearance: a pink body with blue hands and feet → 1
Pulse: 80/min → 1
Grimace: a grimace when stimulated → 1
Activity: some flexion of the arms and legs → 1
Respiration: no breathing → 0
Add
APGAR = 1 + 1 + 1 + 1 + 0 = 4
Interpretation
4 → moderately abnormal
Answer
moderately abnormal
Below 7 at 5 minutes, the score is usually repeated every 5 minutes up to 20 minutes.
9.Enteral & parenteral nutrition calculations
Answer: IBW = 64.1 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
168 cm/2.54 = 66.14 in
Ideal body weight (Devine)
IBW = 50 + 2.3·(66.14 − 60) = 64.13 ≈ 64.1 kg
Answer
IBW = 64.1 kg
10.Enteral & parenteral nutrition calculations
Answer: NPC : N = 117
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: 25·1800/100 = 450 g
amino acids: 6·1800/100 = 108 g
Kilocalories per component
dextrose: 450·3.4 = 1530 kcal
amino acids: 108·4 = 432 kcal
lipid: 250·2 = 500 kcal
Non-protein kcal and nitrogen
NPC = 1530 + 500 = 2030 kcal
N = 108/6.25 = 17.28 g
Ratio
NPC : N = 2030/17.28 = 117.5 ≈ 117 : 1
Answer
NPC : N = 117
Ratios of about 150 : 1 are typical for stable patients; lower ratios give relatively more protein.
11.ECG rhythm strip interpretation
Answer: atrial rate = 300 bpm
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.
Flutter waves
F–F = 5 small boxes = 0.20 s → 1500 ÷ 5 = 300 per minute
QRS complexes
R–R = 15 small boxes = 0.60 s → 1500 ÷ 15 = 100 per minute
conduction ratio = 300 ÷ 100 = 3:1
Answer
atrial rate = 300 bpm
12.ECG rhythm strip interpretation
Answer: paced rhythm, failure to capture
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: 5 QRS complexes in 6 s, × 10 = 50 per minute.
2. Rhythm: the pacing spikes are regular (every 0.92 s), but the R–R is not, because a QRS is missing after some spikes.
3. P waves: none visible.
4. PR interval: not measurable.
5. QRS: 0.14 s and wide after the captured spikes; one spike is not followed by a QRS (no capture).
Interpretation
paced rhythm, failure to capture
Answer
paced rhythm, failure to capture
Failure to capture: the pacemaker fires but the heart does not respond. Textbooks treat it as urgent to report, because the patient may depend on the pacemaker.
13.Prioritization & delegation
Answer: C · Antihypertensive drugs
Why this is the answer
Removing fluid during dialysis can cause hypotension, so blood pressure drugs are often held before treatment as prescribed. Some drugs are also removed by dialysis and given afterwards.
Answer
C · Antihypertensive drugs
14.Prioritization & delegation
Answer: B · Activate the stroke team for urgent imaging, noting when last known well
Why this is the answer
Thrombolysis is time-dependent and needs imaging first to rule out a bleed. The time last known well decides eligibility. Aspirin is not given before imaging, and nothing is given by mouth until swallowing has been screened.
Answer
B · Activate the stroke team for urgent imaging, noting when last known well
15.Infection control & patient safety
Answer: D · To remove items that could be used to harm self or others
Why this is the answer
Belongings are searched with the patient, according to policy, for items such as sharp objects, cords, drugs and lighters. These are stored safely to reduce the risk of self-harm or violence.
Answer
D · To remove items that could be used to harm self or others
16.Infection control & patient safety
Answer: A · “I keep small rugs in the hall so my feet stay warm.”
Why this is the answer
Loose rugs are a common cause of trips and falls and should be removed or secured. Night lights, grab bars and non-slip footwear all reduce fall risk.
Answer
A · “I keep small rugs in the hall so my feet stay warm.”
17.Lab values & electrolytes
Answer: D · A normal rise from placental ALP
Why this is the answer
The placenta produces ALP, so serum ALP normally rises in late pregnancy. With normal bilirubin, ALT and AST, this is expected. Symptoms such as severe itching or raised bile acids would need further review.
Answer
D · A normal rise from placental ALP
18.Lab values & electrolytes
Answer: A · Cloudy fluid, low glucose, high protein, many neutrophils
Why this is the answer
Bacterial meningitis typically gives cloudy CSF with many neutrophils, high protein and low glucose, because bacteria and white cells use glucose. Viral meningitis usually shows lymphocytes with a normal glucose; option C is normal CSF.
Answer
A · Cloudy fluid, low glucose, high protein, many neutrophils