CFRN CORE EXAM TEST 2026 QUESTIONS AND SOLUTIONS
RATED A+
✔✔For every 10 mEq K+ admin, serum K+ increases by _____. - ✔✔0.1
✔✔GOLDMARK
(Causes of Acidosis) - ✔✔G: glycols (ethylene glycol, propylene glycol)
O: oxyprolene (metabolite from Tylenol OD)
L: l-lactate (lactate levels)
D: d-lactate (by-product of propylene glycol)
M: methanols
A: ASA OD
R: renal failure
K: ketoacidosis
✔✔Which acid-base buffering system works minute by minute? - ✔✔Respiratory
✔✔Which acid-base buffering system works second to second? - ✔✔Carbonic acid-
bicarb
✔✔Mass transfusions — citrate - ✔✔A lot of citrate in blood products. It destructs 2-3
DPG.
Also binds to calcium & mag. Therefore always give calcium gluconate (or ca chloride)
& mag to hemorrhagic trauma pt.
Also destroys stress hormones - vasopressin & cortisol.
✔✔Corrected anion gap formula - ✔✔[Na - (Cl + HCO3)] + K
✔✔Normal corrected anion gap range - ✔✔16-20
✔✔ARDS - Vent Settings - ✔✔- High peep to overcome alveolar collapse.
- High fiO2
- Lower tidal volumes 6ml/kg
✔✔ARDS
Common Causes - Direct - ✔✔Direct Lung Injury
- pneumonia
- aspiration
- near drowning
- inhalation injuries
- pulmonary contusion
- pulmonary edema from reperfusion
,✔✔ARDS
Common Causes - Indirect - ✔✔Indirect Lung Injury
- sepsis
- trauma from shock
- CABG
- drug overdose
- blood product administration
- acute pancreatitis
✔✔ARDS Criteria - ✔✔- Acute Onset
- Bil infiltrates on CXR
- PAWP <18 mmHg
- PaO2/FiO2 <200 = ARDS
- PaO2/FiO2 <300 = ALI
✔✔How to determine good quality CXR
RIP - ✔✔R - rotation: pt upright & centered. Spinous process line up, clavicles even.
I - inspiration: look at diaphragm. Which anterior rib intersects diaphragm at
midclavicular line. Should be 5-7. Less than 5 = under inflation. Greater than 7 =
hyperinflation or something in lung field.
P - penetration: should be able to see vertebrae in front of or behind heart.
✔✔Chronic Bronchitis - ✔✔- No destruction of lower airways.
- Excessive mucous production.
- Hypoxemia
- Polycythemia due to increased circulating RBC's to increase carrying capacity of O2 in
blood.
- Increased CO2 retention.
- May have rt heart failure. Fatigue, edema, exertional dyspnea.
"Blue Bloaters"
✔✔Emphysema - ✔✔- Destruction of distal airways decreases the ability to oxygenate.
- V/Q mismatch limits blood flow through oxygenated lung d/t destruction of distal
airways.
- Compensation occurs by decreasing CO & increasing ventilation, hyperventilation.
- Prevention of fresh air coming into lungs & preventing blood flow to capillaries d/t V/Q
mismatch d/t destruction of lower airways.
✔✔COPD X-Ray - ✔✔- Flattened diaphragm
-should still see curve & costophrenic angle.
,- Hyperinflation
- Increased AP diameter of chest in lateral view.
- Long, narrow heart.
- Abnormal air collections.
- Diff to see vertebrae over heart.
✔✔COPD
Capnography Waveform - ✔✔Shark fin d/t resistance to exhalation
✔✔Emphysema X-Ray - ✔✔- Hyperinflation
- Flattening of hemidiaphragm
- Small heart
✔✔Pt with acute onset dyspnea, PAWP 8, CXR with bil infiltrates. What is the most
appropriate diagnosis? - ✔✔ARDS
✔✔Tension Pneumothorax - X-Ray - ✔✔- Vascular marking on affected side may not be
visible.
- Mediastinal & tracheal deviation towards contralateral (unaffected) side.
- Ipsilateral (affected) heart border flattening.
✔✔Tension Pneumothorax
Assessment - peak airway pressures - ✔✔Sudden spike.
Maintain plateau pressure <30.
✔✔Tension Pneumothorax
Needle Decompression Landmark - ✔✔2nd - 3rd intercostal space over the rib.
✔✔Chest tube size - ✔✔4 x ETT size
✔✔Chest Tube insertion
Landmark & positioning - ✔✔- supine or 45 angle
- abduct & externally rotate arm on affected side (arm up & behind head).
- 5th intercostal, mid-axillary line.
✔✔NG Position - ✔✔- >10 cm distal to gastroesophageal junction
- Below left hemidiaphragm
✔✔ETT Position - ✔✔- 5 cm +/- 2 cm above carina
, - at the level of or just below medial ends of clavicle
✔✔CVC Position - ✔✔- Depends on side of entry & intended use.
Right - 1 - 1.5 cm above level of carina.
Left - below carina to get natural curve into vena cava. If left too high, will irritate wall of
vena cava.
✔✔Chest Tube Position - Pneumo - ✔✔- 5th intercostal space, midaxillary line
- tube tip positioned upper pleural cavity.
- tube pointing up.
✔✔Chest Tube Positionjng - Pleural Effusion - ✔✔- tube tip lower pleural cavity.
- tube pointing down.
✔✔Chest tube insertion
>= 1500 ml fluid returned with insertion. - ✔✔Clamp tube to prevent re-expansion
pulmonary edema due to rapid inflation/emptying of lung. Leave clamped until arrive at
destination.
✔✔ECG Changes with P.E.
SI
Q III
T III - ✔✔S I - deep S wave lead I
Q III - pathologic Q wave lead III
T III - T wave inversion lead III
✔✔ECG Changes with P. E. - ✔✔S I
Q III
T III
- Tachycardia
- RBBB
- Rt ventricular strain pattern - t-wave inversion leads V1-V4.
- Rt atrial enlargement - peaked p wave (>2.5 mm) lead II.
- Non-specific ST segment & T wave changes.
✔✔Pathologic Q wave criteria - P.E. - ✔✔>1 mm or 0.04 sec in width
>2 mm deep
>25% of R wave height
RATED A+
✔✔For every 10 mEq K+ admin, serum K+ increases by _____. - ✔✔0.1
✔✔GOLDMARK
(Causes of Acidosis) - ✔✔G: glycols (ethylene glycol, propylene glycol)
O: oxyprolene (metabolite from Tylenol OD)
L: l-lactate (lactate levels)
D: d-lactate (by-product of propylene glycol)
M: methanols
A: ASA OD
R: renal failure
K: ketoacidosis
✔✔Which acid-base buffering system works minute by minute? - ✔✔Respiratory
✔✔Which acid-base buffering system works second to second? - ✔✔Carbonic acid-
bicarb
✔✔Mass transfusions — citrate - ✔✔A lot of citrate in blood products. It destructs 2-3
DPG.
Also binds to calcium & mag. Therefore always give calcium gluconate (or ca chloride)
& mag to hemorrhagic trauma pt.
Also destroys stress hormones - vasopressin & cortisol.
✔✔Corrected anion gap formula - ✔✔[Na - (Cl + HCO3)] + K
✔✔Normal corrected anion gap range - ✔✔16-20
✔✔ARDS - Vent Settings - ✔✔- High peep to overcome alveolar collapse.
- High fiO2
- Lower tidal volumes 6ml/kg
✔✔ARDS
Common Causes - Direct - ✔✔Direct Lung Injury
- pneumonia
- aspiration
- near drowning
- inhalation injuries
- pulmonary contusion
- pulmonary edema from reperfusion
,✔✔ARDS
Common Causes - Indirect - ✔✔Indirect Lung Injury
- sepsis
- trauma from shock
- CABG
- drug overdose
- blood product administration
- acute pancreatitis
✔✔ARDS Criteria - ✔✔- Acute Onset
- Bil infiltrates on CXR
- PAWP <18 mmHg
- PaO2/FiO2 <200 = ARDS
- PaO2/FiO2 <300 = ALI
✔✔How to determine good quality CXR
RIP - ✔✔R - rotation: pt upright & centered. Spinous process line up, clavicles even.
I - inspiration: look at diaphragm. Which anterior rib intersects diaphragm at
midclavicular line. Should be 5-7. Less than 5 = under inflation. Greater than 7 =
hyperinflation or something in lung field.
P - penetration: should be able to see vertebrae in front of or behind heart.
✔✔Chronic Bronchitis - ✔✔- No destruction of lower airways.
- Excessive mucous production.
- Hypoxemia
- Polycythemia due to increased circulating RBC's to increase carrying capacity of O2 in
blood.
- Increased CO2 retention.
- May have rt heart failure. Fatigue, edema, exertional dyspnea.
"Blue Bloaters"
✔✔Emphysema - ✔✔- Destruction of distal airways decreases the ability to oxygenate.
- V/Q mismatch limits blood flow through oxygenated lung d/t destruction of distal
airways.
- Compensation occurs by decreasing CO & increasing ventilation, hyperventilation.
- Prevention of fresh air coming into lungs & preventing blood flow to capillaries d/t V/Q
mismatch d/t destruction of lower airways.
✔✔COPD X-Ray - ✔✔- Flattened diaphragm
-should still see curve & costophrenic angle.
,- Hyperinflation
- Increased AP diameter of chest in lateral view.
- Long, narrow heart.
- Abnormal air collections.
- Diff to see vertebrae over heart.
✔✔COPD
Capnography Waveform - ✔✔Shark fin d/t resistance to exhalation
✔✔Emphysema X-Ray - ✔✔- Hyperinflation
- Flattening of hemidiaphragm
- Small heart
✔✔Pt with acute onset dyspnea, PAWP 8, CXR with bil infiltrates. What is the most
appropriate diagnosis? - ✔✔ARDS
✔✔Tension Pneumothorax - X-Ray - ✔✔- Vascular marking on affected side may not be
visible.
- Mediastinal & tracheal deviation towards contralateral (unaffected) side.
- Ipsilateral (affected) heart border flattening.
✔✔Tension Pneumothorax
Assessment - peak airway pressures - ✔✔Sudden spike.
Maintain plateau pressure <30.
✔✔Tension Pneumothorax
Needle Decompression Landmark - ✔✔2nd - 3rd intercostal space over the rib.
✔✔Chest tube size - ✔✔4 x ETT size
✔✔Chest Tube insertion
Landmark & positioning - ✔✔- supine or 45 angle
- abduct & externally rotate arm on affected side (arm up & behind head).
- 5th intercostal, mid-axillary line.
✔✔NG Position - ✔✔- >10 cm distal to gastroesophageal junction
- Below left hemidiaphragm
✔✔ETT Position - ✔✔- 5 cm +/- 2 cm above carina
, - at the level of or just below medial ends of clavicle
✔✔CVC Position - ✔✔- Depends on side of entry & intended use.
Right - 1 - 1.5 cm above level of carina.
Left - below carina to get natural curve into vena cava. If left too high, will irritate wall of
vena cava.
✔✔Chest Tube Position - Pneumo - ✔✔- 5th intercostal space, midaxillary line
- tube tip positioned upper pleural cavity.
- tube pointing up.
✔✔Chest Tube Positionjng - Pleural Effusion - ✔✔- tube tip lower pleural cavity.
- tube pointing down.
✔✔Chest tube insertion
>= 1500 ml fluid returned with insertion. - ✔✔Clamp tube to prevent re-expansion
pulmonary edema due to rapid inflation/emptying of lung. Leave clamped until arrive at
destination.
✔✔ECG Changes with P.E.
SI
Q III
T III - ✔✔S I - deep S wave lead I
Q III - pathologic Q wave lead III
T III - T wave inversion lead III
✔✔ECG Changes with P. E. - ✔✔S I
Q III
T III
- Tachycardia
- RBBB
- Rt ventricular strain pattern - t-wave inversion leads V1-V4.
- Rt atrial enlargement - peaked p wave (>2.5 mm) lead II.
- Non-specific ST segment & T wave changes.
✔✔Pathologic Q wave criteria - P.E. - ✔✔>1 mm or 0.04 sec in width
>2 mm deep
>25% of R wave height
