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
A goal states: "The patient will report pain of 3/10 or less within one hour of analgesia." After one hour the patient reports 6/10. What should the nurse do?
ARecord the goal as met, as the pain has gone down
BChange the goal to 6/10 or less so that it counts as met
CRecord the goal as not met and review the plan
DWait until the next day to evaluate again
2.Nursing fundamentalsHard
An 82-year-old takes nine regular medicines and has had two falls this month. What is the most useful next step?
AAdvise the patient to stay in bed
BStop all the medicines straight away
CAsk for a full medication review
DAdd a sedative to help them rest
3.Clinical nursingMedium
Which advice is correct for a patient taking levothyroxine?
ATake it on an empty stomach, usually before breakfast
BTake it only on days when feeling tired
CStop taking it once the symptoms improve
DTake it with a large meal to avoid nausea and stomach upset
4.Clinical nursingHard
Why might a patient with diabetes who takes a beta-blocker not notice hypoglycaemia early?
ABeta-blockers raise blood glucose, so true hypoglycaemia cannot happen at all
BBeta-blockers make the patient sleep through the night
CBeta-blockers stop the liver from responding to insulin
DBeta-blockers can mask warning signs such as tremor and a fast heart rate
5.Arterial blood gas interpretationMedium
Practice values: Na⁺ 130 mmol/L, glucose 29.7 mmol/L and urea 10.4 mmol/L. Calculate the serum osmolality Osm = 2·Na⁺ + glucose + urea to the nearest whole number.
Na⁺ 130 mmol/Lglucose 29.7 mmol/Lurea 10.4 mmol/L
Osm = mOsm/kg
6.Arterial blood gas interpretationHard
A practice gas shows a metabolic acidosis: pH 7.24, PaCO₂ 41 mmHg (5.5 kPa), HCO₃⁻ 17 mmol/L. Compare the measured PaCO₂ with Winter’s formula. Click your interpretation.
pH 7.24PaCO₂ 41 mmHg (5.5 kPa)HCO₃⁻ 17 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: yes; secondary diagnosis: yes; ambulatory aid: holds on to furniture; IV therapy or saline lock: yes; gait: impaired; 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). An adult weighs 64 kg and is 178 cm tall. Calculate the BMI and click the WHO weight category.
Practice exercise (made-up values, not clinical guidance). A 53 kg adult (BMI below 30) needs 25 kcal/kg/day. The tube feed provides 1.2 kcal/mL and runs by pump for 24 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 man is 188 cm tall and weighs 125 kg. The practice protocol gives 11 kcal/kg of actual body weight per day if the BMI is 30–50 kg/m², and 25 kcal/kg of ideal body weight (Devine) per day if the BMI is above 50 kg/m². Find the energy goal E in kcal/day. Round to the nearest whole number.
This lead II strip shows atrial flutter. Measure the flutter-wave interval and find the atrial rate in beats per minute.
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
12.ECG rhythm strip interpretationHard
This lead II strip shows a conduction problem between the atria and the ventricles. 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
1atrial fibrillation
2third-degree (complete) AV block
3first-degree AV block
4second-degree AV block type I (Wenckebach)
13.Prioritization & delegationMedium
A nurse teaches a patient about levothyroxine. Which statement shows a need for further teaching?
A“I will take it at breakfast with my calcium tablet.”
B“I will keep taking it even when I feel well.”
C“I will take it on an empty stomach with a glass of water.”
D“I will take it at the same time each morning.”
14.Prioritization & delegationHard
An older patient with pneumonia is newly confused. Which action comes first?
AApply wrist restraints to stop the patient pulling at the IV
BCheck oxygen saturation and the other vital signs
CGive a prescribed as-needed sedative
DAsk the family whether this is normal for the patient
15.Infection control & patient safetyMedium
When opening a sterile pack on a table, which flap is opened first?
AWhichever side flap is easiest to reach
BThe flap furthest away from the nurse
CAll flaps at once
DThe flap closest to the nurse
16.Infection control & patient safetyHard
A patient with a sealed radioactive implant reports that the implant has fallen out onto the bed. What should the nurse do?
AUse long-handled forceps to place it in the lead container
BPick it up with gloved hands and put it in the clinical waste
CLeave it on the bed until the radiation team arrives tomorrow
DAsk the patient to hold it until help arrives
17.Lab values & electrolytesMedium
A vancomycin trough level is above the target range. Which adverse effect is the main concern?
AKidney damage (nephrotoxicity)
BConstipation and bloating
CLow blood glucose (hypoglycemia)
DA raised platelet count (thrombocytosis)
18.Lab values & electrolytesHard
A patient with cirrhosis and ascites has fever and abdominal tenderness. The ascitic fluid neutrophil count is 400 cells/mm³. What does this indicate?
ABleeding into the abdominal cavity
BSpontaneous bacterial peritonitis
CMalignant ascites from cancer
DNormal ascitic fluid in cirrhosis
3Solutions
1.Nursing fundamentals
Answer: C · Record the goal as not met and review the plan
Why this is the answer
Evaluation compares the outcome with the goal. The goal was not met, so the nurse reassesses, reports and revises the plan, for example with a different analgesic.
Answer
C · Record the goal as not met and review the plan
2.Nursing fundamentals
Answer: C · Ask for a full medication review
Why this is the answer
Polypharmacy increases the risk of falls, side effects and interactions in older adults. A review by the prescriber or pharmacist can stop or adjust medicines safely.
Answer
C · Ask for a full medication review
3.Clinical nursing
Answer: A · Take it on an empty stomach, usually before breakfast
Why this is the answer
Levothyroxine is absorbed best on an empty stomach and is usually taken at the same time each morning. It is normally lifelong, with doses adjusted by thyroid blood tests.
Answer
A · Take it on an empty stomach, usually before breakfast
4.Clinical nursing
Answer: D · Beta-blockers can mask warning signs such as tremor and a fast heart rate
Why this is the answer
Tremor, palpitations and anxiety in hypoglycaemia are driven by the sympathetic system, which beta-blockers blunt. Sweating is often still present, and patients need to monitor glucose closely.
Answer
D · Beta-blockers can mask warning signs such as tremor and a fast heart rate
5.Arterial blood gas interpretation
Answer: Osm = 300 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 = 2·130 + 29.7 + 10.4 = 300.1 ≈ 300 mOsm/kg
Answer
Osm = 300 mOsm/kg
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
1.5·17 + 8 = 33.5 → 31.5–35.5 mmHg
Compare
measured: 41 mmHg → added respiratory acidosis
Answer
added respiratory acidosis
7.Clinical assessment scores
Answer: MFS = 110
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: yes → 25
secondary diagnosis: yes → 15
ambulatory aid: holds on to furniture → 30
IV therapy or saline lock: yes → 20
gait: impaired → 20
mental status: knows own limits → 0
Add
Morse total = 25 + 15 + 30 + 20 + 20 + 0 = 110
Answer
MFS = 110
8.Clinical assessment scores
Answer: healthy weight
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 = 64/1.78² = 20.2
Category
healthy weight
Answer
healthy weight
9.Enteral & parenteral nutrition calculations
Answer: R = 46 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 = 25·53 = 1325 kcal/day
Daily volume
V = 1325/1.2 = 1104 mL/day
Pump rate
R = 1104/24 = 46.01 ≈ 46 mL/h
Answer
R = 46 mL/h
10.Enteral & parenteral nutrition calculations
Answer: E = 1375 kcal/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). For BMI 30–50 the energy goal is 11–14 kcal/kg of actual body weight per day; above 50 it is 22–25 kcal/kg of ideal body weight per day. The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Body mass index
BMI = 125/1.88² = 35.37 kg/m²
Energy goal
BMI 30–50: kcal per kg of actual body weight.
E = 11·125 = 1375 kcal/day
Answer
E = 1375 kcal/day
11.ECG rhythm strip interpretation
Answer: atrial rate = 300 bpm
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.
Flutter waves
F–F = 5 small boxes = 0.20 s → 1500 ÷ 5 = 300 per minute
QRS complexes
R–R = 15 small boxes = 0.60 s → 1500 ÷ 15 = 100 per minute
conduction ratio = 300 ÷ 100 = 3:1
Answer
atrial rate = 300 bpm
12.ECG rhythm strip interpretation
Answer: second-degree AV block type I (Wenckebach)
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.
Five steps
1. Rate: 5 QRS complexes in 6 s, × 10 = 50 per minute.
2. Rhythm: regularly irregular, the QRS complexes come in groups separated by a pause (group beating).
3. P waves: upright and regular (P–P 0.88 s, 68 per minute); one P in every 4 is not followed by a QRS.
4. PR interval: lengthens 0.18 → 0.32 → 0.38 s, then a P wave is not conducted.
5. QRS: 0.08 s, narrow (below 0.12 s).
Interpretation
second-degree AV block type I (Wenckebach)
Answer
second-degree AV block type I (Wenckebach)
13.Prioritization & delegation
Answer: A · “I will take it at breakfast with my calcium tablet.”
Why this is the answer
Levothyroxine is best absorbed on an empty stomach and is separated from calcium and iron by several hours. It is usually lifelong, so it is not stopped when the patient feels better.
Answer
A · “I will take it at breakfast with my calcium tablet.”
14.Prioritization & delegation
Answer: B · Check oxygen saturation and the other vital signs
Why this is the answer
New confusion can be caused by hypoxia, sepsis or low blood glucose. Assessing oxygenation and vital signs comes first. Restraints and sedatives treat the behavior, not the cause, and can make delirium worse.
Answer
B · Check oxygen saturation and the other vital signs
15.Infection control & patient safety
Answer: B · The flap furthest away from the nurse
Why this is the answer
The far flap is opened first, then the side flaps and the near flap last, so the nurse never reaches across the exposed sterile area.
Answer
B · The flap furthest away from the nurse
16.Infection control & patient safety
Answer: A · Use long-handled forceps to place it in the lead container
Why this is the answer
A dislodged source is never touched by hand. Long-handled forceps keep distance, the lead container shields the source, and the radiation safety officer is informed immediately.
Answer
A · Use long-handled forceps to place it in the lead container
17.Lab values & electrolytes
Answer: A · Kidney damage (nephrotoxicity)
Why this is the answer
High vancomycin levels are linked to acute kidney injury and, less often, hearing damage. The nurse reports the result before the next dose and checks the creatinine and urine output.
Answer
A · Kidney damage (nephrotoxicity)
18.Lab values & electrolytes
Answer: B · Spontaneous bacterial peritonitis
Why this is the answer
An ascitic neutrophil count of 250 cells/mm³ or more indicates spontaneous bacterial peritonitis, which is treated with antibiotics. It can occur without classic signs, so new confusion or worsening kidney function in cirrhosis should also prompt a diagnostic paracentesis.Checked against:Ascites · MedlinePlus (NIH) (2024); Peritonitis · MedlinePlus (NIH) (2026)