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 patient says, "I've never seen this tablet before," as the nurse offers it. What should the nurse do?
ALeave the tablet on the table for the patient to take later
BStop and recheck the prescription before giving it
CGive half the tablet until the doctor visits
DReassure the patient that the tablet is correct and give it
2.Nursing fundamentalsHard
When is a "clean" (non-sterile) technique acceptable instead of an aseptic technique?
AFor dressing a fresh surgical wound in theatre, provided that non-sterile gloves are worn throughout
BFor inserting a central venous catheter
CFor procedures that do not enter sterile body areas, such as giving an oral medicine
DFor inserting a urinary catheter
3.Clinical nursingMedium
Why are patients asked to fast before a general anaesthetic?
ATo prevent postoperative constipation and abdominal bloating
BTo reduce the risk of aspirating stomach contents
CTo lower the blood glucose before surgery
DTo make the surgery shorter
4.Clinical nursingHard
A patient's urine output has been very low for 12 hours and creatinine has risen sharply. Which drug on the chart is most likely to need review?
AA non-steroidal anti-inflammatory drug such as ibuprofen
BAn emollient cream
CParacetamol at usual doses
DA vitamin supplement
5.Arterial blood gas interpretationMedium
A practice gas shows PaCO₂ 65 mmHg (8.7 kPa). Use the rule that in acute respiratory acidosis HCO₃⁻ rises by 1 mmol/L for every 10 mmHg that PaCO₂ is above 40, starting from HCO₃⁻ 24 mmol/L, to find the expected HCO₃⁻.
A practice gas shows a metabolic alkalosis with HCO₃⁻ 38 mmol/L. Use expected PaCO₂ = 0.7·HCO₃⁻ + 21 to find the expected PaCO₂.
HCO₃⁻ 38 mmol/L
PaCO₂ = mmHg
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A patient has a pulse of 93/min and a blood pressure of 143/93 mmHg. Find the shock index SI = HR/SBP. Round to two decimal places.
HR 93/minBP 143/93 mmHg
SI =
8.Clinical assessment scoresHard
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: none, bed rest or nurse assists; IV therapy or saline lock: no; gait: weak; mental status: knows own limits. Using the cut-offs 0–24 low, 25–44 moderate and 45 or more high, click the fall-risk level.
Practice exercise (made-up values, not clinical guidance). A 76 kg patient has a fluid goal of 30 mL/kg/day and receives all fluid through a feeding tube. The formula is 81% free water and runs at 75 mL/h for 20 hours a day. The rest of the fluid is given as water flushes every 6 hours. What volume V is each flush? Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). Over 24 hours a patient receives 1000 mL of parenteral nutrition with final concentrations of 17.5% dextrose and 5% amino acids, plus 250 mL of 20% lipid emulsion (2 kcal/mL). Find the total energy E the patient receives in kcal per day. Round to the nearest whole number.
1000 mLdextrose 17.5%amino acids 5%lipid 250 mL · 2 kcal/mL
E = kcal/day
11.ECG rhythm strip interpretationMedium
Measure the QT interval on this lead II strip, in seconds.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
QT = s
12.ECG rhythm strip interpretationHard
Interpret this lead II strip with the five steps in order: rate, rhythm, P waves, PR interval, QRS duration. At which step do you find the first abnormal finding? Click it.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
1rate
2rhythm
3P waves
4PR interval
5QRS duration
13.Prioritization & delegationMedium
A patient on hemodialysis has an arteriovenous fistula in the left arm. Which instruction should the nurse give the nursing assistant?
AKeep the left arm wrapped tightly in a bandage at night
BDo not measure blood pressure on the left arm
CHelp the patient carry shopping bags on the left arm
DMeasure blood pressure on the left arm only, every 4 hours
14.Prioritization & delegationHard
A patient is deteriorating quickly. The nurse has called the provider twice, but the provider has not come. What is the best action?
AAsk the patient’s family to call the provider
BWait another hour and call the provider again
CDocument the concern and continue routine care
DActivate the rapid response team
15.Infection control & patient safetyMedium
When is it appropriate to use the override function on an automated dispensing cabinet to take a drug before pharmacist review?
AAt the start of each shift to save time later
BWhenever the nurse is sure of the dose
CWhenever the pharmacist is slow to review new orders and the patient is waiting
DOnly in an urgent situation where delay would harm the patient, per policy
16.Infection control & patient safetyHard
A patient asks for a pain tablet. The record shows none has been given, but the patient says, “The other nurse gave me one earlier.” What should the nurse do?
AGive the tablet, because the record shows none was given
BTell the patient they must be confused
CCheck with the other nurse and the records before giving another dose
DGive half a tablet now, to be safe, and the other half later if needed
17.Lab values & electrolytesMedium
Why must a low total calcium be interpreted with care in a patient with a low serum albumin?
ALow albumin makes every calcium test inaccurate and useless
BAlbumin and calcium are measured with the same chemical reaction, so they always fall together
CMuch calcium is bound to albumin, so total calcium falls even if ionized calcium is normal
DLow albumin always causes true, symptomatic hypocalcemia
18.Lab values & electrolytesHard
A woman with preeclampsia is receiving IV magnesium sulfate. Her urine output has fallen and her creatinine is rising. Why is this a concern?
APoor kidney function makes the magnesium level fall quickly
BMagnesium causes potassium loss, so the kidneys release more fluid
CMagnesium is broken down by the liver, so it will stop working soon
DMagnesium is excreted by the kidneys, so it can build up to toxic levels
3Solutions
1.Nursing fundamentals
Answer: B · Stop and recheck the prescription before giving it
Why this is the answer
A patient questioning a medicine may be a sign of an error. The nurse holds the dose, checks the prescription and the drug and explains before giving it.
Answer
B · Stop and recheck the prescription before giving it
2.Nursing fundamentals
Answer: C · For procedures that do not enter sterile body areas, such as giving an oral medicine
Why this is the answer
Aseptic technique is required when entering normally sterile sites or handling key parts of invasive devices. Routine non-invasive tasks only need standard precautions.
Answer
C · For procedures that do not enter sterile body areas, such as giving an oral medicine
3.Clinical nursing
Answer: B · To reduce the risk of aspirating stomach contents
Why this is the answer
Under general anaesthesia the airway reflexes are lost, so food or fluid in the stomach could be regurgitated and inhaled. Fasting reduces the risk of aspiration pneumonitis.
Answer
B · To reduce the risk of aspirating stomach contents
4.Clinical nursing
Answer: A · A non-steroidal anti-inflammatory drug such as ibuprofen
Why this is the answer
In acute kidney injury, nephrotoxic drugs (such as NSAIDs and aminoglycosides) and drugs that reduce renal perfusion (such as ACE inhibitors and diuretics) are reviewed and often stopped.
Answer
A · A non-steroidal anti-inflammatory drug such as ibuprofen
5.Arterial blood gas interpretation
Answer: HCO₃⁻ = 26.5 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.
Change in PaCO₂
|65 − 40| = 25 mmHg → 2.5 × 10 mmHg
Expected HCO₃⁻
HCO₃⁻ = 24 + 1·2.5 = 26.5 mmol/L
Answer
HCO₃⁻ = 26.5 mmol/L
6.Arterial blood gas interpretation
Answer: PaCO₂ = 47.6 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.
Expected PaCO₂
0.7·38 + 21 = 47.6 mmHg
Answer
PaCO₂ = 47.6 mmHg
The rise has a limit: PaCO₂ rarely goes above about 55 mmHg from compensation alone.
7.Clinical assessment scores
Answer: SI = 0.65
Blood pressure values: pulse pressure PP = SBP − DBP. Mean arterial pressure MAP ≈ (SBP + 2·DBP)/3 = DBP + PP/3, an estimate based on the heart spending about two thirds of each beat in diastole at a normal heart rate (less accurate when the heart rate is fast); a MAP of at least about 65 mmHg is a common target for organ perfusion. The shock index SI = heart rate/SBP is normally about 0.5–0.7; a value above about 1 is a warning sign of shock.
Shock index
SI = 93/143 = 0.6503 ≈ 0.65
Answer
SI = 0.65
Within or below the usual 0.5–0.7.
8.Clinical assessment scores
Answer: low risk
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: none, bed rest or nurse assists → 0
IV therapy or saline lock: no → 0
gait: weak → 10
mental status: knows own limits → 0
Add
Morse total = 0 + 0 + 0 + 0 + 10 + 0 = 10
Risk level
10 → low risk
Answer
low risk
9.Enteral & parenteral nutrition calculations
Answer: V = 266 mL
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.
Fluid goal
30·76 = 2280 mL/day
Free water from the formula
75·20 = 1500 mL
1500·0.81 = 1215 mL
Water still needed
2280 − 1215 = 1065 mL/day
Volume per flush
24/6 = 4 flushes
V = 1065/4 = 266.3 ≈ 266 mL
Answer
V = 266 mL
10.Enteral & parenteral nutrition calculations
Answer: E = 1295 kcal/day
Parenteral nutrition: dextrose provides 3.4 kcal/g, amino acids 4 kcal/g and lipid emulsion the kcal/mL stated (2 kcal/mL for 20%, 1.1 kcal/mL for 10%). Grams = % × mL/100. Non-protein kcal (NPC) = dextrose + lipid kcal; nitrogen = protein/6.25. The glucose infusion rate (GIR) in mg/kg/min = dextrose mg/(kg × minutes). The numbers are for practice only; at the bedside always follow local protocols and have high-risk doses double-checked.
Grams of dextrose and amino acids
dextrose: 17.5·1000/100 = 175 g
amino acids: 5·1000/100 = 50 g
Kilocalories per component
dextrose: 175·3.4 = 595 kcal
amino acids: 50·4 = 200 kcal
lipid: 250·2 = 500 kcal
Total energy
E = 595 + 200 + 500 = 1295 kcal/day
Answer
E = 1295 kcal/day
11.ECG rhythm strip interpretation
Answer: QT = 0.38 s
QT and QTc: the QT interval runs from the start of the QRS complex to the end of the T wave. It shortens as the heart rate rises, so it is corrected for rate with the R–R interval in seconds: Bazett QTc = QT/√RR and Fridericia QTc = QT/∛RR. Bazett is the formula most textbooks use; it over-corrects at fast rates, where Fridericia is preferred. Limits differ between references: a QTc above about 0.45 s in men or 0.46 s in women is usually called prolonged, and above 0.50 s markedly prolonged.
Measure
9.5 small boxes from the start of the QRS to the end of the T wave
Convert
QT = 9.5 × 0.04 s = 0.38 s
Answer
QT = 0.38 s
A rough rule: at normal rates the QT should be less than half the R–R interval (here R–R = 1.00 s).
12.ECG rhythm strip interpretation
Answer: rhythm
Five steps for every strip: 1. rate (300 or 1500 method, or the 6-second method if irregular); 2. rhythm: are the R–R intervals equal; 3. P waves: present, upright in lead II, one before every QRS and all alike; 4. PR interval: 0.12–0.20 s and constant; 5. QRS duration: below 0.12 s. Only after the five steps name the rhythm. Normal sinus rhythm passes all five: 60–100/min, regular, upright P before every QRS, PR 0.12–0.20 s, QRS below 0.12 s.
Five steps
1. Rate: 7 QRS complexes in 6 s, × 10 = 70 per minute.
2. Rhythm: irregular, R–R from 0.76 to 1.10 s, lengthening and shortening gradually.
3. P waves: upright, one before every QRS, all alike.
4. PR interval: 0.18 s, constant, within 0.12–0.20 s.
5. QRS: 0.10 s, narrow (below 0.12 s).
First abnormal step
rhythm → sinus arrhythmia
Answer
rhythm
13.Prioritization & delegation
Answer: B · Do not measure blood pressure on the left arm
Why this is the answer
Blood pressure cuffs, tight bands and heavy loads can damage or block a fistula. The arm with the access is protected, and the nurse checks it for a thrill and bruit.
Answer
B · Do not measure blood pressure on the left arm
14.Prioritization & delegation
Answer: D · Activate the rapid response team
Why this is the answer
Nurses can call the rapid response team directly when a patient is deteriorating. The nurse also informs the charge nurse and follows the chain of command about the provider’s lack of response.
Answer
D · Activate the rapid response team
15.Infection control & patient safety
Answer: D · Only in an urgent situation where delay would harm the patient, per policy
Why this is the answer
Pharmacist review checks for allergies, interactions and dosing errors. Overrides are limited to true emergencies and drugs on an approved list, because bypassing review has led to serious errors.
Answer
D · Only in an urgent situation where delay would harm the patient, per policy
16.Infection control & patient safety
Answer: C · Check with the other nurse and the records before giving another dose
Why this is the answer
Undocumented doses can lead to double dosing. The nurse checks with colleagues and the dispensing records, then gives the drug only once it is clear whether a dose was given.
Answer
C · Check with the other nurse and the records before giving another dose
17.Lab values & electrolytes
Answer: C · Much calcium is bound to albumin, so total calcium falls even if ionized calcium is normal
Why this is the answer
About 40% of calcium is bound to albumin. When albumin is low, total calcium falls although ionized calcium may be normal. A corrected calcium or a measured ionized calcium gives the true picture.
Answer
C · Much calcium is bound to albumin, so total calcium falls even if ionized calcium is normal
18.Lab values & electrolytes
Answer: D · Magnesium is excreted by the kidneys, so it can build up to toxic levels
Why this is the answer
Magnesium is cleared by the kidneys, so falling urine output and rising creatinine raise the risk of toxicity. The nurse checks deep tendon reflexes, respiratory rate and level of consciousness, reports the findings and keeps calcium gluconate available as the antidote.
Answer
D · Magnesium is excreted by the kidneys, so it can build up to toxic levels