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
Which nursing record entry is the best example of objective documentation?
A"Had a good appetite today and enjoyed lunch."
B"Seemed to enjoy the meal."
C"Ate well, as usual."
D"Ate half of lunch; drank 200 mL of water."
2.Nursing fundamentalsHard
On the day after surgery, a patient's new stoma has turned dark purple. What should the nurse do?
AWait a week to see whether it changes
BRecord it as normal bruising after surgery and recheck tomorrow
CClean it firmly to remove the colour
DReport it urgently, as the stoma may be losing its blood supply
3.Clinical nursingMedium
Why are older adults at higher risk of dehydration?
ATheir kidneys hold on to too much water
BThey always drink large amounts of tea
CTheir sense of thirst is often reduced
DTheir body water content increases with age
4.Clinical nursingHard
Why must blood samples for a cross-match be labelled at the bedside immediately after they are taken?
ATo keep the sample warm so the cells do not break down in transit
BTo prevent "wrong blood in tube" errors that can cause fatal reactions
CTo let the patient sign the label
DTo speed up the laboratory's computer system and reduce the waiting time
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 129 mmol/L, glucose 25.6 mmol/L and urea 19.9 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 129 mmol/Lglucose 25.6 mmol/Lurea 19.9 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
Practice values: Na⁺ 140, Cl⁻ 102, HCO₃⁻ 22 mmol/L and albumin 22 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 20/min, SpO₂ 97% on room air, blood pressure 100/60 mmHg, pulse 120/min, alert, temperature 37.8 °C. What is the NEWS2 total score?
RR 20SpO₂ 97%airSBP 100HR 120AT 37.8 °C
NEWS2 =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). At 1 minute after birth, a practice newborn has a pink body with blue hands and feet, a heart rate of 70/min, a grimace when stimulated, some flexion of the arms and legs and slow, irregular breathing with a weak cry. 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 woman who is 177 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 4% 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.
1800 mLdextrose 25%amino acids 4%lipid 500 mL · 1.1 kcal/mL
E = kcal/day
11.ECG rhythm strip interpretationMedium
This lead II strip shows sinus rhythm with one pause. Measure the pause, the R–R interval across it, in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
pause = s
12.ECG rhythm strip interpretationHard
This lead II strip shows an AV block, so the atria and the ventricles beat at different rates. The QRS complexes are regular: find the ventricular rate in beats per minute (1500 method, whole number).
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
ventricular rate = bpm
13.Prioritization & delegationMedium
Which practice makes a shift handover safest?
AHanding over only the patients who had problems during the shift
BA quick chat in the corridor with no notes taken
CA structured format, such as SBAR, with time for questions
DLeaving a sticky note on the computer screen for the next nurse
14.Prioritization & delegationHard
Using ESI, a stable adult with abdominal pain will need blood tests and a CT scan, but has a heart rate of 130/min. Which statement is correct?
AThe nurse should consider level 2 because of the danger-zone vital sign
BThe patient is level 5 because the pain is not severe
CThe patient is level 4 because the blood tests and the scan count as one resource
DVital signs never change the ESI level
15.Infection control & patient safetyMedium
A patient is receiving opioids for pain. Which sign usually comes before opioid-induced respiratory depression?
AIncreasing sedation
BDilated pupils
CRising blood pressure
DDiarrhea
16.Infection control & patient safetyHard
A nurse calculates a child’s prescribed dose and finds it is ten times higher than the usual dose for the child’s weight. What should the nurse do?
AHold the dose and verify it with the prescriber and pharmacist
BGive half the dose and watch the child closely
CGive it, because the prescriber must have a reason
DGive one-tenth of the dose without telling anyone about it
17.Lab values & electrolytesMedium
In countries that screen all pregnant women (such as the US), a vaginal-rectal swab is taken at about 36–37 weeks. Which organism is it screening for?
AHepatitis B virus
BCandida albicans
CStaphylococcus aureus
DGroup B Streptococcus
18.Lab values & electrolytesHard
During an IV magnesium sulfate infusion, which assessment best detects toxicity early?
ABowel sounds and abdominal girth
BSkin color and capillary refill every hour
CBlood glucose and pupil size every hour
DKnee reflexes, respiratory rate and urine output
3Solutions
1.Nursing fundamentals
Answer: D · "Ate half of lunch; drank 200 mL of water."
Why this is the answer
Objective entries describe what was observed or measured. Vague or judgemental phrases such as "good" or "as usual" cannot be checked or compared.
Answer
D · "Ate half of lunch; drank 200 mL of water."
2.Nursing fundamentals
Answer: D · Report it urgently, as the stoma may be losing its blood supply
Why this is the answer
A dusky, purple or black stoma suggests ischaemia or necrosis, which can need surgery. The nurse reports it to the surgical team at once.
Answer
D · Report it urgently, as the stoma may be losing its blood supply
3.Clinical nursing
Answer: C · Their sense of thirst is often reduced
Why this is the answer
With age, thirst is blunted, kidney concentrating ability falls and total body water decreases. Cognitive or physical problems can also make it harder to drink.
Answer
C · Their sense of thirst is often reduced
4.Clinical nursing
Answer: B · To prevent "wrong blood in tube" errors that can cause fatal reactions
Why this is the answer
A sample labelled with the wrong patient's details can lead to incompatible blood being issued. Labelling at the bedside after positive identification is a key transfusion safety step.
Answer
B · To prevent "wrong blood in tube" errors that can cause fatal reactions
5.Arterial blood gas interpretation
Answer: Osm = 304 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 = 2·129 + 25.6 + 19.9 = 303.5 ≈ 304 mOsm/kg
Answer
Osm = 304 mOsm/kg
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 = 140 − (102 + 22) = 16
Correction for albumin
16 + 0.25·(40 − 22) = 20.5 mmol/L
Answer
AGc = 20.5 mmol/L
Above about 12 after correction: a high anion gap.
7.Clinical assessment scores
Answer: NEWS2 = 4
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 20/min → 0
SpO₂ 97% → 0
on air → 0
SBP 100 mmHg → 2
HR 120/min → 2
alert (A) → 0
T 37.8 °C → 0
Add
NEWS2 = 0 + 0 + 0 + 2 + 2 + 0 + 0 = 4
Answer
NEWS2 = 4
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: 70/min → 1
Grimace: a grimace when stimulated → 1
Activity: some flexion of the arms and legs → 1
Respiration: slow, irregular breathing with a weak cry → 1
Add
APGAR = 1 + 1 + 1 + 1 + 1 = 5
Interpretation
5 → moderately abnormal
Answer
moderately abnormal
9.Enteral & parenteral nutrition calculations
Answer: IBW = 67.8 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
177 cm/2.54 = 69.69 in
Ideal body weight (Devine)
IBW = 45.5 + 2.3·(69.69 − 60) = 67.78 ≈ 67.8 kg
Answer
IBW = 67.8 kg
10.Enteral & parenteral nutrition calculations
Answer: E = 2368 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: 25·1800/100 = 450 g
amino acids: 4·1800/100 = 72 g
Kilocalories per component
dextrose: 450·3.4 = 1530 kcal
amino acids: 72·4 = 288 kcal
lipid: 500·1.1 = 550 kcal
Total energy
E = 1530 + 288 + 550 = 2368 kcal/day
Answer
E = 2368 kcal/day
11.ECG rhythm strip interpretation
Answer: pause = 2.04 s
Narrow-complex tachycardia and pauses: supraventricular tachycardia (SVT) is a regular tachycardia at about 150–250/min with narrow QRS complexes; the P waves are usually not visible because they are hidden in the QRS complex or the T wave. Sinus tachycardia in an adult at rest is usually below about 150/min and has a visible P wave before every QRS; atrial flutter with 2:1 conduction often runs at about 150/min and shows sawtooth waves. In sinus arrest the sinus node stops firing for a moment: a pause with no P wave and no QRS whose length is not a whole number of P–P cycles (a pause of exactly two or three cycles points to sinus exit block instead).
Measure
51 small boxes from R to R across the pause
Convert
pause = 51 × 0.04 s = 2.04 s
Compare with P–P
2.04 ÷ 0.88 ≈ 2.3 P–P cycles, not a whole number
Answer
pause = 2.04 s
No P wave appears in the pause, and the pause is not a whole number of P–P cycles: sinus arrest. A pause of exactly two or three cycles would point to sinus exit block.
12.ECG rhythm strip interpretation
Answer: ventricular rate = 43 bpm
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.
Atrial rate
P–P = 15 small boxes = 0.60 s → 1500 ÷ 15 = 100 ≈ 100 per minute
Ventricular rate
R–R = 35 small boxes = 1.40 s → 1500 ÷ 35 = 42.86 ≈ 43 per minute
Answer
ventricular rate = 43 bpm
Answer
ventricular rate = 43 bpm
Third-degree block with a narrow-complex junctional escape (usually 40–60 per minute).
13.Prioritization & delegation
Answer: C · A structured format, such as SBAR, with time for questions
Why this is the answer
Handover is a high-risk moment for errors. A structured format and the chance to ask questions help the next nurse understand each patient’s condition and priorities.
Answer
C · A structured format, such as SBAR, with time for questions
14.Prioritization & delegation
Answer: A · The nurse should consider level 2 because of the danger-zone vital sign
Why this is the answer
In ESI, a patient who needs two or more resources is level 3, but danger-zone vital signs such as a very fast heart rate should make the nurse consider level 2.
Answer
A · The nurse should consider level 2 because of the danger-zone vital sign
15.Infection control & patient safety
Answer: A · Increasing sedation
Why this is the answer
Sedation increases before respiratory depression occurs, so sedation levels are checked regularly along with breathing. A patient who is getting harder to wake needs the opioid held and the prescriber informed.
Answer
A · Increasing sedation
16.Infection control & patient safety
Answer: A · Hold the dose and verify it with the prescriber and pharmacist
Why this is the answer
Tenfold errors are common in pediatrics, usually from decimal or unit mistakes. The nurse holds the dose and clarifies it, and never changes the dose on their own.
Answer
A · Hold the dose and verify it with the prescriber and pharmacist
17.Lab values & electrolytes
Answer: D · Group B Streptococcus
Why this is the answer
Group B streptococci can colonize the vagina and rectum and can cause severe infection in newborns. Women who test positive receive IV antibiotics during labor to reduce transmission to the baby. The UK does not screen all women routinely; it uses a risk-based approach instead.
Answer
D · Group B Streptococcus
18.Lab values & electrolytes
Answer: D · Knee reflexes, respiratory rate and urine output
Why this is the answer
Loss of the knee reflex is usually the first sign of magnesium toxicity, followed by slow breathing. Magnesium is cleared by the kidneys, so falling urine output increases the risk. Calcium gluconate is the antidote.
Answer
D · Knee reflexes, respiratory rate and urine output