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 11/min, SpO₂ 96% on room air, blood pressure 78/46 mmHg, pulse 76/min, alert, temperature 38.4 °C. What is the NEWS2 total score?
RR 11SpO₂ 96%airSBP 78HR 76AT 38.4 °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 16/min, SpO₂ 88% on room air, blood pressure 136/82 mmHg, pulse 58/min, alert, temperature 37.0 °C. Which clinical risk group does the patient fall into? Click it.
RR 16SpO₂ 88%airSBP 136HR 58AT 37.0 °C
1low
2low–medium
3medium
4high
3.Arterial blood gas interpretationMedium
Practice values: Na⁺ 135 mmol/L, glucose 5.8 mmol/L and urea 12.8 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 135 mmol/Lglucose 5.8 mmol/Lurea 12.8 mmol/L
Osm = mOsm/kg
4.Arterial blood gas interpretationHard
A practice gas shows pH 7.26, PaCO₂ 23 mmHg (3.1 kPa) and HCO₃⁻ 10 mmol/L, with Na⁺ 132 and Cl⁻ 85 mmol/L. Use the anion gap and the delta ratio to click the best interpretation.
A patient is found on the floor beside the bed. What should the nurse do first?
AAsk the patient to stand up on their own
BLift the patient straight back into bed
CCheck responsiveness and look for injuries before moving them
DComplete the incident report first, then go back to assess the patient fully
6.Nursing fundamentalsHard
An 86-year-old has new confusion and a temperature of 37.1 °C. Why should infection still be considered?
AOlder adults normally have a higher body temperature
BA temperature of 37.1 °C is a fever in older adults
COlder adults often have a weaker fever response to infection
DConfusion is always caused by infection in older adults
7.Nursing math & unit conversionsMedium
Practice exercise (made-up values, not clinical guidance). A dose is charted at 3:45 PM. Which entry is the same time on the 24-hour clock? Click it.
3:45 PM
114:45
215:45
303:45
416:45
8.Nursing math & unit conversionsHard
Practice exercise (made-up values, not clinical guidance). A serum creatinine result is 406 µmol/L. Using 1 mg/dL = 88.4 µmol/L for creatinine, find c in mg/dL. Round to two decimal places.
406 µmol/L1 mg/dL = 88.4 µmol/L
c = mg/dL
3Solutions
1.Clinical assessment scores
Answer: NEWS2 = 5
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 11/min → 1
SpO₂ 96% → 0
on air → 0
SBP 78 mmHg → 3
HR 76/min → 0
alert (A) → 0
T 38.4 °C → 1
Add
NEWS2 = 1 + 0 + 0 + 3 + 0 + 0 + 1 = 5
Answer
NEWS2 = 5
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 16/min → 0
SpO₂ 88% → 3
on air → 0
SBP 136 mmHg → 0
HR 58/min → 0
alert (A) → 0
T 37.0 °C → 0
Total and red scores
NEWS2 = 0 + 3 + 0 + 0 + 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: Osm = 289 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 = 2·135 + 5.8 + 12.8 = 288.6 ≈ 289 mOsm/kg
Answer
Osm = 289 mOsm/kg
4.Arterial blood gas interpretation
Answer: pure high-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 = 132 − (85 + 10) = 37
Delta ratio
(37 − 12)/(24 − 10) = 1.786
pure high-gap acidosis
Answer
pure high-gap acidosis
5.Nursing fundamentals
Answer: C · Check responsiveness and look for injuries before moving them
Why this is the answer
The nurse first calls for help and assesses the patient, including for head and hip injury. The patient is moved only when safe, using proper equipment, and the doctor is informed.
Answer
C · Check responsiveness and look for injuries before moving them
6.Nursing fundamentals
Answer: C · Older adults often have a weaker fever response to infection
Why this is the answer
Older adults may not mount a fever, and infection can show up as confusion, falls or reduced eating instead. A normal temperature does not rule out infection in this group.
Answer
C · Older adults often have a weaker fever response to infection
7.Nursing math & unit conversions
Answer: 15:45
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
3 PM → 3 + 12 = 15
Answer
15:45
Answer
15:45
8.Nursing math & unit conversions
Answer: c = 4.59 mg/dL
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.