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 does not open the eyes at all, makes no sounds and shows as the best motor response: no movement at all. 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). An adult weighs 102 kg and is 172 cm tall. Calculate the BMI and click the WHO weight category.
102 kg172 cm
1underweight
2healthy weight
3overweight
4obesity class I
5obesity class II
6obesity class III
3.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.28, PaCO₂ 64 mmHg (8.5 kPa) and HCO₃⁻ 29 mmol/L. The primary disorder is respiratory acidosis. How far is it compensated? Click your answer.
pH 7.28PaCO₂ 64 mmHg (8.5 kPa)HCO₃⁻ 29 mmol/L
1uncompensated
2partially compensated
3fully compensated
4.Arterial blood gas interpretationHard
Practice values: Na⁺ 135, Cl⁻ 112, HCO₃⁻ 11 mmol/L and albumin 30 g/L. Find the albumin-corrected anion gap AGc = AG + 0.25·(40 − albumin).
Which adverse effect is a particular risk with NSAIDs such as ibuprofen?
ABreathing slowing down
BStomach irritation and bleeding
CLow blood sugar
DSevere constipation that lasts for weeks
6.Nursing fundamentalsHard
A postoperative wound drain that had drained little suddenly fills with bright red blood. What should the nurse do?
ACheck the patient's vital signs and report it urgently
BClamp the drain and tell no one
CEmpty the drain and record it at the next routine round
DRemove the drain because it is not working
7.Nursing math & unit conversionsMedium
Practice exercise (made-up values, not clinical guidance). A drip-rate calculation gives 127.902 gtt/min. The rule in this exercise is that drip rates are rounded to the nearest whole drop. What value x do you record?
127.902 gtt/min
x = gtt/min
8.Nursing math & unit conversionsHard
Practice exercise (made-up values, not clinical guidance). A prescription reads ½ tbsp of an oral suspension every 6 hours for 7 days. Using 1 tbsp = 15 mL, how many mL V are needed for the whole course?
½ tbspevery 6 hours7 days1 tbsp = 15 mL
V = mL
3Solutions
1.Clinical assessment scores
Answer: severe
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: does not open the eyes at all → 1
V: makes no sounds → 1
M: no movement at all → 1
Add
GCS = 1 + 1 + 1 = 3
Severity
GCS 3 → severe
Answer
severe
2.Clinical assessment scores
Answer: obesity class I
Body mass index: BMI = weight (kg)/height (m)², with the height converted to metres first. With pounds and inches, BMI = 703 × weight (lb)/height (in)². WHO adult categories: below 18.5 underweight, 18.5–24.9 healthy weight, 25.0–29.9 overweight, 30.0–34.9 obesity class I, 35.0–39.9 obesity class II and 40 or more obesity class III.
BMI
BMI = 102/1.72² = 34.48
Category
obesity class I
Answer
obesity class I
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 7.28: acidaemia (below 7.35)
PaCO₂ 64 mmHg: high (35–45)
HCO₃⁻ 29 mmol/L: high (22–26)
Compensation
partially compensated
Answer
partially compensated
4.Arterial blood gas interpretation
Answer: AGc = 14.5 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 = 135 − (112 + 11) = 12
Correction for albumin
12 + 0.25·(40 − 30) = 14.5 mmol/L
Answer
AGc = 14.5 mmol/L
Above about 12 after correction: a high anion gap.
5.Nursing fundamentals
Answer: B · Stomach irritation and bleeding
Why this is the answer
NSAIDs can irritate the stomach lining and cause ulcers and bleeding. They are taken with food, avoided in some patients and may also affect the kidneys.
Answer
B · Stomach irritation and bleeding
6.Nursing fundamentals
Answer: A · Check the patient's vital signs and report it urgently
Why this is the answer
A sudden increase in fresh blood may mean active bleeding. The nurse assesses for signs of shock, such as a rising pulse and falling blood pressure, and escalates immediately.
Answer
A · Check the patient's vital signs and report it urgently
7.Nursing math & unit conversions
Answer: x = 128 gtt/min
Rounding: look at the digit just after the place you round to: 5 or more rounds up, 4 or less leaves the digit as it is. Round only the final answer, never the steps. Typical exam rules: volumes of 1 mL or more to the nearest tenth, volumes below 1 mL to the nearest hundredth, drip rates to whole drops and weights to one decimal place; always follow the rule the question states.
Digit in the ones place
127.902 → 7
Only the next digit decides
127.902 → 9
9 is 5 or more, so round 7 up.
The digits after it (02) are ignored: round once, never step by step.
Round
x = 128 gtt/min
Answer
x = 128 gtt/min
8.Nursing math & unit conversions
Answer: V = 210 mL
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.