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
When washing a patient's eyes, how should each eye be wiped?
AFrom the inner corner outwards, using a clean part of the cloth for each eye
BIn small circles over the closed eyelid of both eyes
CFrom the outer corner inwards, using the same part of the cloth for both
DOnly the eye that looks dirty needs cleaning
2.Nursing fundamentalsHard
Which finding suggests a patient may be developing a pressure ulcer category 1?
AIntact skin with non-blanching redness over a bony area
BAn open blister with a red base
CFull-thickness skin loss with visible fat but no exposed bone
DExposed bone or tendon
3.Clinical nursingMedium
Which drug is first-line in an acute asthma attack?
AAn oral beta-blocker
BAn oral antihistamine such as cetirizine taken every few hours
CA long-acting inhaled corticosteroid, used alone at a higher dose
DA nebulised or inhaled short-acting beta2-agonist (salbutamol/albuterol)
4.Clinical nursingHard
A patient with back pain develops numbness around the anus and genitals and new difficulty passing urine. Which condition should be suspected?
ACauda equina syndrome
BKidney stones
CConstipation
DSimple muscle strain
5.Arterial blood gas interpretationMedium
A practice arterial blood gas shows pH 7.43, PaCO₂ 48 mmHg (6.4 kPa) and HCO₃⁻ 31 mmol/L. The primary disorder is metabolic alkalosis. How far is it compensated? Click your answer.
pH 7.43PaCO₂ 48 mmHg (6.4 kPa)HCO₃⁻ 31 mmol/L
1uncompensated
2partially compensated
3fully compensated
6.Arterial blood gas interpretationHard
A practice gas shows a respiratory acidosis: pH 7.23, PaCO₂ 84 mmHg (11.2 kPa), HCO₃⁻ 34 mmol/L. Use the rules ‘HCO₃⁻ rises 1 mmol/L per 10 mmHg (acute) or 3.5 mmol/L per 10 mmHg (chronic)’ to classify it. Click your answer.
pH 7.23PaCO₂ 84 mmHg (11.2 kPa)HCO₃⁻ 34 mmol/L
1acute
2chronic
3acute on chronic
7.Clinical assessment scoresMedium
Practice exercise (made-up values, not clinical guidance). A practice chart records GCS 8, with E2 and V3. What motor score M was recorded, and which response does it describe? Give the number.
GCS 8E2V3
M =
8.Clinical assessment scoresHard
Practice exercise (made-up values, not clinical guidance). At 1 minute after birth, a practice newborn has blue or pale skin all over, no heartbeat, no response to stimulation, limp limbs with no muscle tone and no breathing. Score the APGAR and click how the score is interpreted.
Practice exercise (made-up values, not clinical guidance). A man is 165 cm tall and weighs 83 kg. Find the actual weight as a percentage of the ideal body weight, %IBW, using the Devine formula (1 in = 2.54 cm). Round to the nearest whole number.
Practice exercise (made-up values, not clinical guidance). A critically ill woman is 176 cm tall and weighs 166 kg. The practice protocol gives 14 kcal/kg of actual body weight per day if the BMI is 30–50 kg/m², and 24 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.
Measure the QT interval and the R–R interval on this regular lead II strip, then calculate the rate-corrected QTc with Fridericia’s formula QTc = QT/∛RR (both in seconds). Give the answer in seconds to three decimals.
lead II, 25 mm/s, 10 mm/mV1 small box = 0.04 s, 1 large box = 0.20 sstrip length 6 s
QTc = s
12.ECG rhythm strip interpretationHard
Identify the rhythm on this lead II strip. 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
2ventricular tachycardia
3ventricular fibrillation
4sinus tachycardia
13.Prioritization & delegationMedium
When making patient assignments, what should the charge nurse consider first?
ALetting staff choose the patients they prefer
BGiving each nurse patients in rooms next to each other
CMatching each patient’s needs to staff competence
DGiving the newest staff the most complex patients
14.Prioritization & delegationHard
Which patient on a renal unit should the nurse see first?
AA patient on peritoneal dialysis whose drained fluid is clear
BA patient asking for advice about a low-phosphate diet
CA patient on hemodialysis who missed yesterday’s session and now has muscle weakness and an irregular pulse
DA patient whose arteriovenous fistula has a strong thrill and bruit
15.Infection control & patient safetyMedium
A patient has highly contagious viral conjunctivitis. Which teaching is most important?
AWash hands often and do not share towels, pillows or eye drops
BWear a surgical mask whenever someone else is in the room
CKeep using the same contact lenses to protect the eyes
DRub the eyes gently to remove the discharge
16.Infection control & patient safetyHard
A newly hired nurse has these hepatitis B results: HBsAg negative, anti-HBs positive, anti-HBc negative. What do they show?
AA current hepatitis B infection
BPast infection that has now cleared
CNo immunity, so the vaccine is needed
DImmunity from hepatitis B vaccination
17.Lab values & electrolytesMedium
A patient receives subcutaneous enoxaparin (a low-molecular-weight heparin). Which statement about monitoring is correct?
AThe INR is used to adjust each dose, as with warfarin
BThe aPTT must be checked every 6 hours to adjust the dose
CNo blood tests of any kind are ever needed
DNo routine aPTT; platelets and kidney function are checked instead
18.Lab values & electrolytesHard
A patient with a stable INR on warfarin starts rifampin (rifampicin) for tuberculosis. Two weeks later the INR is 1.3. What is the most likely explanation?
ARifampin raises the INR, so it is wrong
BTuberculosis causes the INR to fall
CRifampin speeds up warfarin metabolism
DRifampin contains a lot of vitamin K
3Solutions
1.Nursing fundamentals
Answer: A · From the inner corner outwards, using a clean part of the cloth for each eye
Why this is the answer
Wiping from the inner to the outer canthus moves debris away from the tear duct. Using a clean part of the cloth for each eye prevents spreading infection between them.
Answer
A · From the inner corner outwards, using a clean part of the cloth for each eye
2.Nursing fundamentals
Answer: A · Intact skin with non-blanching redness over a bony area
Why this is the answer
Category 1 is intact skin with non-blanchable erythema. Category 2 involves partial-thickness loss such as a blister; categories 3 and 4 are deeper.
Answer
A · Intact skin with non-blanching redness over a bony area
3.Clinical nursing
Answer: D · A nebulised or inhaled short-acting beta2-agonist (salbutamol/albuterol)
Why this is the answer
Short-acting beta2-agonists relieve bronchospasm within minutes. Oxygen to target, steroids and other treatments are added according to severity.
Answer
D · A nebulised or inhaled short-acting beta2-agonist (salbutamol/albuterol)
4.Clinical nursing
Answer: A · Cauda equina syndrome
Why this is the answer
Saddle anaesthesia, bladder or bowel dysfunction and leg symptoms with back pain suggest cauda equina syndrome. It needs an emergency MRI and surgical review to prevent permanent loss of function.
Answer
A · Cauda equina syndrome
5.Arterial blood gas interpretation
Answer: fully 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 7.43: within 7.35–7.45
PaCO₂ 48 mmHg: high (35–45)
HCO₃⁻ 31 mmol/L: high (22–26)
Compensation
Clinically, also check the expected compensation: for a metabolic alkalosis PaCO₂ ≈ 0.7·HCO₃⁻ + 21 = 40.7–44.7 mmHg, so the measured 48 mmHg points to an additional respiratory acidosis (a mixed disorder). The answer above is the ROME exam classification.
fully compensated
Answer
fully compensated
6.Arterial blood gas interpretation
Answer: acute on chronic
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 HCO₃⁻
acute: 24 + 1·4.4 = 28.4 mmol/L
chronic: 24 + 3.5·4.4 = 39.4 mmol/L
Compare
measured: 34 mmol/L → acute on chronic
Answer
acute on chronic
7.Clinical assessment scores
Answer: M = 3
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.
Motor score
M = 8 − 2 − 3 = 3
M3: abnormal flexion of the arms (decorticate posture)
Answer
M = 3
8.Clinical assessment scores
Answer: low
APGAR score: five signs, each scored 0, 1 or 2, checked at 1 and 5 minutes after birth. Appearance (colour): blue or pale 0, pink body with blue extremities 1, pink all over 2. Pulse: absent 0, below 100/min 1, 100/min or more 2. Grimace (reflex irritability): none 0, grimace 1, cry, cough or sneeze 2. Activity (tone): limp 0, some flexion 1, active movement 2. Respiration: absent 0, slow or irregular with a weak cry 1, good with a strong cry 2. A total of 7–10 is reassuring, 4–6 moderately abnormal and 0–3 low.
Score each sign
Appearance: blue or pale skin all over → 0
Pulse: 0 → 0
Grimace: no response to stimulation → 0
Activity: limp limbs with no muscle tone → 0
Respiration: no breathing → 0
Add
APGAR = 0 + 0 + 0 + 0 + 0 = 0
Interpretation
0 → low
Answer
low
9.Enteral & parenteral nutrition calculations
Answer: %IBW = 135 %
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.
Ideal body weight (Devine)
165 cm/2.54 = 64.96 in
IBW = 50 + 2.3·(64.96 − 60) = 61.41 kg
Percentage of ideal body weight
%IBW = 83/61.41·100 = 135.2 ≈ 135%
Answer
%IBW = 135%
10.Enteral & parenteral nutrition calculations
Answer: E = 1605 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 = 166/1.76² = 53.59 kg/m²
Ideal body weight (Devine)
176 cm/2.54 = 69.29 in
IBW = 45.5 + 2.3·(69.29 − 60) = 66.87 kg
Energy goal
BMI above 50: kcal per kg of ideal body weight.
E = 24·66.87 = 1605 kcal/day
Answer
E = 1605 kcal/day
11.ECG rhythm strip interpretation
Answer: QTc = 0.409 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
QT = 9 × 0.04 = 0.36 s
RR = 17 × 0.04 = 0.68 s
Fridericia’s formula
QTc = 0.36/∛0.68 = 0.36/0.8794 = 0.409 s
Answer
QTc = 0.409 s
Within the usual limits (about 0.45 s for men, 0.46 s for women). (409 ms)
12.ECG rhythm strip interpretation
Answer: ventricular tachycardia
Ventricular rhythms: ventricular tachycardia is a run of three or more wide (0.12 s or more) complexes in a row at more than 100/min, usually 150–250/min, regular, without related P waves. Ventricular fibrillation is a chaotic, irregular waveform with no identifiable P waves, QRS complexes or T waves and no countable rate. Asystole is an almost flat line with no ventricular activity; a flat line is always confirmed by checking the patient, the leads and the gain and a second lead. In resuscitation guidelines VF and pulseless VT are the shockable rhythms and asystole is not.
Five steps
1. Rate: R–R = 10 small boxes, 1500 ÷ 10 ≈ 150 per minute.
2. Rhythm: regular, every R–R is 0.40 s.
3. P waves: none identifiable.
4. PR interval: not measurable.
5. QRS: 0.16 s, wide (0.12 s or more).
Interpretation
ventricular tachycardia
Answer
ventricular tachycardia
In resuscitation guidelines VF and pulseless VT are the shockable rhythms. This is identification practice only.
13.Prioritization & delegation
Answer: C · Matching each patient’s needs to staff competence
Why this is the answer
Assignments are based mainly on patient acuity and needs and on each staff member’s skills and scope. Geography and continuity of care help, but they come after safety.
Answer
C · Matching each patient’s needs to staff competence
14.Prioritization & delegation
Answer: C · A patient on hemodialysis who missed yesterday’s session and now has muscle weakness and an irregular pulse
Why this is the answer
A missed dialysis session lets potassium build up. Muscle weakness and an irregular pulse suggest hyperkalemia, which can cause fatal arrhythmias, so the nurse assesses at once, arranges cardiac monitoring and escalates. A thrill and bruit and clear effluent are expected findings, and diet advice can wait.
Answer
C · A patient on hemodialysis who missed yesterday’s session and now has muscle weakness and an irregular pulse
15.Infection control & patient safety
Answer: A · Wash hands often and do not share towels, pillows or eye drops
Why this is the answer
Viral conjunctivitis spreads easily by contact with eye secretions. Hand hygiene, not touching the eyes and not sharing towels, pillows or eye products reduce spread.
Answer
A · Wash hands often and do not share towels, pillows or eye drops
16.Infection control & patient safety
Answer: D · Immunity from hepatitis B vaccination
Why this is the answer
The vaccine contains surface antigen, so it produces anti-HBs only. A negative anti-HBc shows there has been no natural infection, and a negative HBsAg rules out current infection.
Answer
D · Immunity from hepatitis B vaccination
17.Lab values & electrolytes
Answer: D · No routine aPTT; platelets and kidney function are checked instead
Why this is the answer
Enoxaparin has a predictable effect, so the aPTT is not used to monitor it. Platelet counts help detect heparin-induced thrombocytopenia, and kidney function matters because the drug is cleared by the kidneys. Anti-Xa levels may be used in pregnancy, obesity or kidney disease.
Answer
D · No routine aPTT; platelets and kidney function are checked instead
18.Lab values & electrolytes
Answer: C · Rifampin speeds up warfarin metabolism
Why this is the answer
Rifampin induces liver enzymes that break down warfarin, so warfarin's effect falls and the INR drops, increasing clot risk. The INR is monitored closely and the dose adjusted; the reverse happens when rifampin is stopped.