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
How should adhesive tape be removed from an older patient's fragile skin?
AAfter wetting it with alcohol rub
BSlowly, low and close to the skin, while supporting the skin
CQuickly in one firm pull, straight upwards and away from the skin
DBy pulling it away from the wound as hard as possible
2.Nursing fundamentalsHard
A patient spills hot tea on their forearm. What is the best immediate first aid?
ACool the burn under cool running water for about 20 minutes
BCover it with butter or a greasy cream
CPut ice or an ice pack directly on the burn for about 10 minutes
DPop any blisters to let the heat escape
3.Clinical nursingMedium
Which signs suggest a blood transfusion reaction in the first minutes?
ASlow, steady rise in haemoglobin over the next day
BMild hunger
CFever, chills, back pain and low blood pressure
DImproved colour and energy
4.Clinical nursingHard
A patient with cirrhosis and a large tense abdomen undergoes paracentesis. Why may albumin be given?
ATo stop the liver making more bile
BTo increase urine potassium
CTo treat infection in the fluid
DTo reduce the risk of circulatory dysfunction after large-volume fluid removal
5.Arterial blood gas interpretationMedium
A practice gas shows a metabolic acidosis with HCO₃⁻ 14 mmol/L. Use Winter’s formula to find the expected PaCO₂ (the centre of the range) in mmHg.
HCO₃⁻ 14 mmol/L
PaCO₂ = mmHg
6.Arterial blood gas interpretationHard
A practice gas shows a metabolic acidosis: pH 7.13, PaCO₂ 34 mmHg (4.5 kPa), HCO₃⁻ 11 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.
pH 7.13PaCO₂ 34 mmHg (4.5 kPa)HCO₃⁻ 11 mmol/L
1appropriate compensation
2added respiratory acidosis
3added respiratory alkalosis
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice patient is assessed with the Morse fall scale: history of falling in the last 3 months: no; secondary diagnosis: no; ambulatory aid: holds on to furniture; IV therapy or saline lock: no; gait: weak; mental status: knows own limits. Find the Morse total MFS.
0–125
MFS =
8.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 96% on supplemental oxygen, blood pressure 88/52 mmHg, pulse 70/min, alert, temperature 36.9 °C. Which clinical risk group does the patient fall into? Click it.
Practice exercise (made-up values, not clinical guidance). An 87 kg adult (BMI below 30) needs 25 kcal/kg/day. The tube feed provides 1 kcal/mL and runs by pump for 16 hours a day. At what rate R do you set the pump, in mL/h? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). A critically ill woman is 165 cm tall and weighs 107 kg. The practice protocol gives 2 g of protein per kg of ideal body weight (Devine) per day if the BMI is 30 to under 40 kg/m², and 2.5 g/kg of ideal body weight per day if the BMI is 40 kg/m² or more. Find the protein goal P in g/day. Round to the nearest whole number.
Interpret this lead II rhythm strip. Which rhythm is it? Click your answer.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
1sinus bradycardia
2normal sinus rhythm
3sinus tachycardia
4first-degree AV block
12.ECG rhythm strip interpretationHard
This lead II strip shows an AV block, so the atria and the ventricles beat at different rates. Measure the P–P interval and find the atrial 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
atrial rate = bpm
13.Prioritization & delegationMedium
A patient is receiving a blood transfusion. Which task can the nurse delegate to a nursing assistant?
AAssessing the patient for signs of a transfusion reaction
BMeasuring and reporting vital signs at the times set by the nurse
CDeciding whether to stop the transfusion if the patient has chills
DStarting the transfusion once the blood arrives
14.Prioritization & delegationHard
A patient who is 7 weeks pregnant has one-sided lower abdominal pain, pain in the shoulder tip, a heart rate of 120/min and a blood pressure of 88/54 mmHg. What is most likely?
AA urinary tract infection
BSevere morning sickness
CA normal early pregnancy
DA ruptured ectopic pregnancy
15.Infection control & patient safetyMedium
Where should the dispersive (grounding) pad for electrosurgery be placed?
AOn clean, dry skin over a well-perfused muscle, close to the surgical site
BOver a bony prominence such as the hip bone
COn skin that is wet with antiseptic prep
DOver an area with scar tissue or a tattoo, so that the pad does not slip
16.Infection control & patient safetyHard
A bag of chemotherapy drug leaks onto the floor. What is the first step?
AAsk the cleaner to mop it up with the usual mop
BWipe it up quickly with paper towels and bare hands
CPut on the spill kit’s protective equipment and contain the spill
DLeave it to dry, then clean it up at the end of the shift
17.Lab values & electrolytesMedium
In the US, when is a pregnant woman without known risk factors usually screened for gestational diabetes?
AAt about 24–28 weeks of pregnancy
BAt about 6–8 weeks of pregnancy
CAt about 38–40 weeks of pregnancy
DOnly after the baby is born
18.Lab values & electrolytesHard
An 82-year-old woman without a catheter has a urine culture growing bacteria, but no fever, urinary symptoms or change in mental state. What is the best interpretation?
APyelonephritis, which needs admission and IV fluids today
BA urinary tract infection that needs urgent IV antibiotics
CAsymptomatic bacteriuria, usually not treated with antibiotics
DContamination, so the culture must be repeated every week
3Solutions
1.Nursing fundamentals
Answer: B · Slowly, low and close to the skin, while supporting the skin
Why this is the answer
Peeling the tape back low and slow while holding the skin reduces the pulling force on fragile skin. Adhesive removers can also help.
Answer
B · Slowly, low and close to the skin, while supporting the skin
2.Nursing fundamentals
Answer: A · Cool the burn under cool running water for about 20 minutes
Why this is the answer
Cool running water for about 20 minutes reduces pain and depth of injury. Ice can damage tissue further, grease holds heat in, and blisters are left intact to protect the skin.
Answer
A · Cool the burn under cool running water for about 20 minutes
3.Clinical nursing
Answer: C · Fever, chills, back pain and low blood pressure
Why this is the answer
An acute haemolytic or febrile reaction can cause fever, rigors, loin or back pain, breathlessness and hypotension. Stop the transfusion and call for help.
Answer
C · Fever, chills, back pain and low blood pressure
4.Clinical nursing
Answer: D · To reduce the risk of circulatory dysfunction after large-volume fluid removal
Why this is the answer
Large-volume paracentesis can cause hypotension and renal impairment. Albumin infusion helps maintain the circulating volume.
Answer
D · To reduce the risk of circulatory dysfunction after large-volume fluid removal
5.Arterial blood gas interpretation
Answer: PaCO₂ = 29 mmHg
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.
Winter’s formula
PaCO₂ = 1.5·14 + 8 = 29 mmHg
range: 27–31 mmHg
Answer
PaCO₂ = 29 mmHg
6.Arterial blood gas interpretation
Answer: added respiratory 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.
Expected PaCO₂
1.5·11 + 8 = 24.5 → 22.5–26.5 mmHg
Compare
measured: 34 mmHg → added respiratory acidosis
Answer
added respiratory acidosis
7.Clinical assessment scores
Answer: MFS = 40
Morse fall scale: six items. History of falling: no 0, yes 25. Secondary diagnosis: no 0, yes 15. Ambulatory aid: none, bed rest or nurse assistance 0; crutches, cane or walker 15; holding on to furniture 30. IV therapy or saline lock: no 0, yes 20. Gait: normal, bed rest or wheelchair 0; weak 10; impaired 20. Mental status: knows own limits 0; overestimates or forgets limits 15. The total runs from 0 to 125. Risk cut-offs differ between hospitals; a common set is 0–24 low, 25–44 moderate and 45 or more high.
Score each item
history of falling in the last 3 months: no → 0
secondary diagnosis: no → 0
ambulatory aid: holds on to furniture → 30
IV therapy or saline lock: no → 0
gait: weak → 10
mental status: knows own limits → 0
Add
Morse total = 0 + 0 + 30 + 0 + 10 + 0 = 40
Answer
MFS = 40
8.Clinical assessment scores
Answer: 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 96% → 0
on oxygen → 2
SBP 88 mmHg → 3
HR 70/min → 0
alert (A) → 0
T 36.9 °C → 0
Total and red scores
NEWS2 = 0 + 0 + 2 + 3 + 0 + 0 + 0 = 5
At least one parameter scores 3.
Risk group
medium
Answer
medium
A total of 5 or more calls for an urgent clinical response.
9.Enteral & parenteral nutrition calculations
Answer: R = 136 mL/h
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.
Energy needed
E = 25·87 = 2175 kcal/day
Daily volume
V = 2175/1 = 2175 mL/day
Pump rate
R = 2175/16 = 135.9 ≈ 136 mL/h
Answer
R = 136 mL/h
10.Enteral & parenteral nutrition calculations
Answer: P = 114 g/day
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. Obesity in critical illness (ASPEN/SCCM 2016): BMI = weight/height² (kg/m²). The protein goal is 2 g/kg of ideal body weight per day for BMI 30–40 and up to 2.5 g/kg of ideal body weight per day for BMI 40 and above. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Body mass index
BMI = 107/1.65² = 39.3 kg/m²
Ideal body weight (Devine)
165 cm/2.54 = 64.96 in
IBW = 45.5 + 2.3·(64.96 − 60) = 56.91 kg
Protein goal
BMI 30 to under 40: 2 g per kg of ideal body weight.
P = 2·56.91 = 113.8 ≈ 114 g/day
Answer
P = 114 g/day
11.ECG rhythm strip interpretation
Answer: first-degree AV block
Rhythm criteria (lead II): sinus rhythm has an upright P wave before every QRS, a constant PR of 0.12–0.20 s and a narrow QRS: normal sinus rhythm at 60–100/min, sinus bradycardia below 60, sinus tachycardia above 100. Atrial fibrillation: no P waves, a fibrillatory baseline and an irregularly irregular R–R. Atrial flutter: sawtooth flutter waves at about 250–350/min with a fixed conduction ratio such as 2:1 or 4:1. First-degree AV block: sinus rhythm with a constant PR above 0.20 s. Junctional rhythm: narrow QRS at 40–60/min with absent or inverted P waves (PR below 0.12 s, or P after the QRS). A PVC is an early, wide (0.12 s or more), bizarre QRS without a P wave, with the T wave in the opposite direction and usually a full compensatory pause; in bigeminy every second beat is a PVC.
Five steps
1. Rate: R–R = 20 small boxes, 1500 ÷ 20 ≈ 75 per minute.
2. Rhythm: regular, every R–R is 0.80 s.
3. P waves: upright, one before every QRS, all alike.
4. PR interval: 0.32 s, constant, longer than 0.20 s.
5. QRS: 0.08 s, narrow (below 0.12 s).
Interpretation
first-degree AV block
Answer
first-degree AV block
12.ECG rhythm strip interpretation
Answer: atrial rate = 68 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 = 22 small boxes = 0.88 s → 1500 ÷ 22 = 68.18 ≈ 68 per minute
Ventricular rate
5 QRS complexes in 6 s × 10 = 50 per minute
Answer
atrial rate = 68 bpm
Answer
atrial rate = 68 bpm
Second-degree type I (Wenckebach): 4 P waves for every 3 QRS complexes.
13.Prioritization & delegation
Answer: B · Measuring and reporting vital signs at the times set by the nurse
Why this is the answer
An assistant can measure vital signs and report them. Assessing for a reaction, starting the transfusion and deciding to stop it need the nurse’s judgement.
Answer
B · Measuring and reporting vital signs at the times set by the nurse
14.Prioritization & delegation
Answer: D · A ruptured ectopic pregnancy
Why this is the answer
A ruptured ectopic pregnancy causes internal bleeding, with abdominal pain, shoulder-tip pain and signs of shock. It is a surgical emergency.
Answer
D · A ruptured ectopic pregnancy
15.Infection control & patient safety
Answer: A · On clean, dry skin over a well-perfused muscle, close to the surgical site
Why this is the answer
The pad returns the current safely. Good contact over a well-perfused muscle prevents burns, while bony areas, scars, hair and moisture reduce contact and can cause burns at the pad site.
Answer
A · On clean, dry skin over a well-perfused muscle, close to the surgical site
16.Infection control & patient safety
Answer: C · Put on the spill kit’s protective equipment and contain the spill
Why this is the answer
Hazardous drug spills are handled with a spill kit, including chemotherapy-tested gloves, a gown and eye protection. The area is secured and the spill is contained, cleaned and disposed of as hazardous waste, then reported.
Answer
C · Put on the spill kit’s protective equipment and contain the spill
17.Lab values & electrolytes
Answer: A · At about 24–28 weeks of pregnancy
Why this is the answer
Placental hormones increase insulin resistance in the second half of pregnancy, so US guidance recommends screening all women at 24–28 weeks, with earlier testing for those with risk factors. In the UK, NICE recommends an oral glucose tolerance test at 24–28 weeks only for women with risk factors.
Answer
A · At about 24–28 weeks of pregnancy
18.Lab values & electrolytes
Answer: C · Asymptomatic bacteriuria, usually not treated with antibiotics
Why this is the answer
Asymptomatic bacteriuria is common in older adults and usually should not be treated, because treatment brings adverse effects and resistance without benefit. Exceptions include pregnancy and some urological procedures.
Answer
C · Asymptomatic bacteriuria, usually not treated with antibiotics