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.
Nursing math & unit conversions
Metric steps
1 kg = 1000 g, 1 g = 1000 mg, 1 mg = 1000 mcg, 1 L = 1000 mL
Weight and length
1 kg = 2.2 lb, 1 lb = 16 oz, 1 in = 2.54 cm, 1 ft = 12 in
Household measures
1 tsp = 5 mL, 1 tbsp = 15 mL, 1 fl oz = 30 mL, 1 cup = 8 fl oz = 240 mL
Write the given quantity with its unit and the unit you want.
Pick the equivalent: 1000 between kg, g, mg and mcg or L and mL; 1 kg = 2.2 lb; 1 tsp = 5 mL, 1 tbsp = 15 mL, 1 fl oz = 30 mL, 1 cup = 240 mL.
Write it as a fraction so that the unwanted unit cancels; for a rate, use one fraction per unit that changes.
Check the direction: a smaller unit gives a bigger number.
Round only the final answer, to the precision the question names.
2Practice problems
1.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice patient after a head injury opens the eyes when spoken to, is oriented to person, place and time and shows as the best motor response: moves a hand to the site of pressure (localises). Work out the GCS and classify the head injury by it. Click your answer.
1mild
2moderate
3severe
2.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 18/min, SpO₂ 99% on room air, blood pressure 84/50 mmHg, pulse 76/min, alert, temperature 37.1 °C. Which clinical risk group does the patient fall into? Click it.
RR 18SpO₂ 99%airSBP 84HR 76AT 37.1 °C
1low
2low–medium
3medium
4high
3.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.20, PaCO₂ 24 mmHg (3.2 kPa) and HCO₃⁻ 9 mmol/L. The primary disorder is metabolic acidosis. How far is it compensated? Click your answer.
pH 7.20PaCO₂ 24 mmHg (3.2 kPa)HCO₃⁻ 9 mmol/L
1uncompensated
2partially compensated
3fully compensated
4.Arterial blood gas interpretationHard
At sea level, a practice gas taken on 50% oxygen shows PaO₂ 84 mmHg (11.2 kPa) and PaCO₂ 45 mmHg (6.0 kPa). Use PAO₂ = FiO₂·(760 − 47) − PaCO₂/0.8 to find the A–a gradient.
Why is early mobilisation important for older inpatients?
AWalking makes older patients' bones grow longer
BIt lets staff change the beds more easily while patients are up
CBed rest quickly causes loss of strength and independence
DOlder patients do not need sleep during the day
6.Nursing fundamentalsHard
A patient has a generalised tonic-clonic seizure in bed. What should the nurse do?
AGive a drink of water as soon as the jerking starts
BProtect the head, move objects away, time it and do not restrain
CHold the arms and legs firmly so that the jerking movements stop more quickly
DPut a spoon between the teeth to stop tongue biting
7.Nursing math & unit conversionsMedium
Practice exercise (made-up values, not clinical guidance). A dose is charted at 08:35 (24-hour clock). Which entry is the same time on the 12-hour clock? Click it.
08:35
17:35 AM
28:35 AM
38:35 PM
410:35 AM
8.Nursing math & unit conversionsHard
Practice exercise (made-up values, not clinical guidance). An order reads 10 mcg/kg/min for a patient who weighs 80 kg. Express the dose rate D in mg/h. Round to two decimal places.
10 mcg/kg/min80 kg
D = mg/h
3Solutions
1.Clinical assessment scores
Answer: mild
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.
Score each area
E: opens the eyes when spoken to → 3
V: is oriented to person, place and time → 5
M: moves a hand to the site of pressure (localises) → 5
Add
GCS = 3 + 5 + 5 = 13
Severity
GCS 13 → mild
Answer
mild
2.Clinical assessment scores
Answer: low–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 18/min → 0
SpO₂ 99% → 0
on air → 0
SBP 84 mmHg → 3
HR 76/min → 0
alert (A) → 0
T 37.1 °C → 0
Total and red scores
NEWS2 = 0 + 0 + 0 + 3 + 0 + 0 + 0 = 3
At least one parameter scores 3.
Risk group
low–medium
Answer
low–medium
A single score of 3 needs an urgent review even when the total is low.
3.Arterial blood gas interpretation
Answer: partially compensated
Reading a blood gas (ROME): first the pH: below 7.35 is acidaemia, above 7.45 alkalaemia. Then find the value that explains it. PaCO₂ (normal 35–45 mmHg, 4.7–6.0 kPa) is the respiratory part and moves Opposite to the pH in a respiratory disorder; HCO₃⁻ (normal 22–26 mmol/L) is the metabolic part and moves in the same direction as the pH (Respiratory Opposite, Metabolic Equal). The other value shows the compensation: normal means uncompensated; abnormal in the direction that pulls the pH back while the pH is still abnormal means partially compensated; a normal pH with both values abnormal means fully compensated. Ranges differ slightly between laboratories; these are practice values.
ROME, value by value
pH 7.20: acidaemia (below 7.35)
PaCO₂ 24 mmHg: low (35–45)
HCO₃⁻ 9 mmol/L: low (22–26)
Compensation
Clinically, also check the expected compensation: Winter’s formula expects PaCO₂ 19.5–23.5 mmHg, so the measured 24 mmHg points to an additional respiratory acidosis (a mixed disorder). The answer above is the ROME exam classification.
partially compensated
Answer
partially compensated
4.Arterial blood gas interpretation
Answer: A–a gradient = 216.3 mmHg
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.
Answer: C · Bed rest quickly causes loss of strength and independence
Why this is the answer
Older adults lose muscle strength quickly in bed, which leads to falls and loss of independence. Getting up, dressed and moving as soon as safe helps prevent this deconditioning.
Answer
C · Bed rest quickly causes loss of strength and independence
6.Nursing fundamentals
Answer: B · Protect the head, move objects away, time it and do not restrain
Why this is the answer
During a seizure the nurse keeps the patient safe, notes the time and the features, and never puts anything in the mouth. Afterwards the patient is placed in the recovery position and the airway checked.
Answer
B · Protect the head, move objects away, time it and do not restrain
7.Nursing math & unit conversions
Answer: 8:35 AM
24-hour clock: from 1 PM onwards add 12 to the hour (3:45 PM = 15:45). Midnight to 12:59 AM is 00:00–00:59, and 12:00–12:59 PM stays 12:00–12:59. Going back, subtract 12 from hours 13–23 and add PM; hours 00 become 12 AM. Count time across midnight in two parts: up to 24:00 (00:00), then from 00:00 on.
Convert the hour
08 → 8 AM
Answer
8:35 AM
Answer
8:35 AM
8.Nursing math & unit conversions
Answer: D = 48 mg/h
Dimensional analysis: write the given quantity, then multiply by conversion factors written as fractions (for example 60 min/1 h or 1 mg/1000 mcg) so that each unwanted unit appears once on top and once underneath and cancels. When only the wanted unit is left, calculate. Use the equivalents the question gives and round only the final answer.
Set up the chain
D = 10 mcg/kg/min × 80 kg × (60 min/1 h) × (1 mg/1000 mcg)