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). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 20/min, SpO₂ 95% on supplemental oxygen, blood pressure 136/82 mmHg, pulse 104/min, alert, temperature 36.5 °C. What is the NEWS2 total score?
RR 20SpO₂ 95%O₂SBP 136HR 104AT 36.5 °C
NEWS2 =
2.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). Use the NEWS2 chart (SpO₂ scale 1) for these observations: respiration rate 25/min, SpO₂ 97% on room air, blood pressure 110/66 mmHg, pulse 88/min, alert, temperature 37.0 °C. Which clinical risk group does the patient fall into? Click it.
RR 25SpO₂ 97%airSBP 110HR 88AT 37.0 °C
1low
2low–medium
3medium
4high
3.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.55, PaCO₂ 39 mmHg (5.2 kPa) and HCO₃⁻ 33 mmol/L. The primary disorder is metabolic alkalosis. How far is it compensated? Click your answer.
pH 7.55PaCO₂ 39 mmHg (5.2 kPa)HCO₃⁻ 33 mmol/L
1uncompensated
2partially compensated
3fully compensated
4.Arterial blood gas interpretationHard
A practice gas shows pH 7.25, PaCO₂ 21 mmHg (2.8 kPa) and HCO₃⁻ 9 mmol/L, with Na⁺ 137 and Cl⁻ 107 mmol/L. Use the anion gap and the delta ratio to click the best interpretation.
BThe patient will walk 20 metres with a frame by Friday
CThe patient will try to eat more
DThe patient will improve mobility
6.Nursing fundamentalsHard
A patient's notes record a penicillin allergy with a rash. The new prescription is for amoxicillin. What should the nurse do?
AGive an antihistamine first, then the amoxicillin
BGive the dose, as amoxicillin is a different drug from penicillin itself
CWithhold it and contact the prescriber, as amoxicillin is a penicillin
DGive half the dose and watch for a rash
7.Nursing math & unit conversionsMedium
Practice exercise (made-up values, not clinical guidance). A patient is 6 ft 11 in tall. Using 1 ft = 12 in and 1 in = 2.54 cm, find the height h in centimetres, to the nearest whole centimetre.
6 ft 11 in1 ft = 12 in1 in = 2.54 cm
h = cm
8.Nursing math & unit conversionsHard
Practice exercise (made-up values, not clinical guidance). An infusion delivers 5 mg/h. Express this dose rate D in mcg/min. Round to one decimal place.
5 mg/h1 mg = 1000 mcg1 h = 60 min
D = mcg/min
3Solutions
1.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 95% → 1
on oxygen → 2
SBP 136 mmHg → 0
HR 104/min → 1
alert (A) → 0
T 36.5 °C → 0
Add
NEWS2 = 0 + 1 + 2 + 0 + 1 + 0 + 0 = 4
Answer
NEWS2 = 4
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 25/min → 3
SpO₂ 97% → 0
on air → 0
SBP 110 mmHg → 1
HR 88/min → 0
alert (A) → 0
T 37.0 °C → 0
Total and red scores
NEWS2 = 3 + 0 + 0 + 1 + 0 + 0 + 0 = 4
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: uncompensated
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 7.55: alkalaemia (above 7.45)
PaCO₂ 39 mmHg: normal (35–45)
HCO₃⁻ 33 mmol/L: high (22–26)
Compensation
Clinically, also check the expected compensation: for a metabolic alkalosis PaCO₂ ≈ 0.7·HCO₃⁻ + 21 = 42.1–46.1 mmHg, so the measured 39 mmHg points to an additional respiratory alkalosis (a mixed disorder). The answer above is the ROME exam classification.
uncompensated
Answer
uncompensated
4.Arterial blood gas interpretation
Answer: added normal-gap acidosis
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 = 137 − (107 + 9) = 21
Delta ratio
(21 − 12)/(24 − 9) = 0.6
added normal-gap acidosis
Answer
added normal-gap acidosis
5.Nursing fundamentals
Answer: B · The patient will walk 20 metres with a frame by Friday
Why this is the answer
A SMART goal states exactly what is expected, how it will be measured and by when. "Walk 20 metres with a frame by Friday" can be checked; "feel better" cannot.
Answer
B · The patient will walk 20 metres with a frame by Friday
6.Nursing fundamentals
Answer: C · Withhold it and contact the prescriber, as amoxicillin is a penicillin
Why this is the answer
Amoxicillin is a penicillin and can cause the same allergic reaction, including anaphylaxis. The nurse withholds it and asks for an alternative.
Answer
C · Withhold it and contact the prescriber, as amoxicillin is a penicillin
7.Nursing math & unit conversions
Answer: h = 211 cm
Household measures and weight: nursing exams use rounded equivalents: 1 teaspoon (tsp) = 5 mL, 1 tablespoon (tbsp) = 15 mL = 3 tsp, 1 fluid ounce (fl oz) = 30 mL = 2 tbsp, and 1 cup = 8 fl oz = 240 mL. For weight, 1 kg = 2.2 lb and 1 lb = 16 oz; for length, 1 inch = 2.54 cm. Set the conversion up so that the unit you do not want cancels out.
Height in inches
6·12 + 11 = 83 in
Inches to centimetres
h = 83·2.54 = 210.8 ≈ 211 cm
Answer
h = 211 cm
8.Nursing math & unit conversions
Answer: D = 83.3 mcg/min
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.