Critical Care Final Exam Review

Crunch the Numbers

Lung Logic

Read the Waves

Dial it in

Pressure's On

Houston, We Have a Problem

Critical Condition

100

A patient has the following values:

Hb = 12 g/dL
SaO₂ = 95%
PaO₂ = 80 mm Hg

What is the patient’s arterial oxygen content (CaO₂)?

15.5 mL O₂/dL

(1.34 × 12 × 0.95) + (0.003 × 80)

100

A patient with severe pneumonia remains profoundly hypoxemic despite receiving 100% oxygen. Imaging shows complete consolidation of the left lower lobe. What V/Q abnormality best explains the refractory hypoxemia?

Shunt

100

What points make up the inspiratory time?

A-D

100

A 70-kg IBW patient is intubated following an opioid overdose. Before intubation: RR: 4/min, SpO₂: 86% on 4 L/min NC, Breath sounds: clear bilaterally
ABG: pH 7.18 /PaCO₂ 72 /PaO₂ 58 /HCO₃ 26

The patient has no known pulmonary disease.

What initial vent settings would you recommend?

A. VC 420, RR-16, +8, 100%

B. VC 420, RR-24, +8, 100%

C. VC 560, RR-16, +8, 100%

D. VC 420, RR-12, +8, 100%

A. VC 420, RR-16, +8, 100%

100

A mechanically ventilated patient has the following measurements:

PIP: 34 cm H₂O
Plateau pressure: 27 cm H₂O
Set PEEP: +10 cm H₂O
Total PEEP: +12 cm H₂O
Mean airway pressure: 17 cm H₂O
FiO₂: 0.50
SpO₂: 94%

What is the patient’s driving pressure?

15 cm H₂O

Driving pressure = Pplat − total PEEP
= 27 − 12

100

A patient underwent tracheostomy placement 4 days ago. During repositioning, the tracheostomy tube becomes dislodged and the patient becomes acutely hypoxemic. How would you respond?

Do not blindly reinsert the tracheostomy tube due to the immature stoma. Provide oxygen/ventilation via the upper airway while occluding the stoma and call for assistance to reestablish the airway.

100

A patient is admitted following a witnessed aspiration event and is placed on HFNC at 60 L/min and FiO₂ 0.80. Two hours later, the patient has the following findings:

RR: 34/min with marked accessory muscle use, HR: 118/min, SpO₂: 85%, Breath sounds: coarse crackles bilaterally

pH: 7.29/ PaCO₂: 58 mm Hg/ PaO₂: 49 mm Hg

What would you recommend to the team?
A. Place on BiPAP
B. Continue HFNC, just increase FiO2
C. Intubate and mechanically ventilate
D. Place on CPAP

C. Intubate and mechanically ventilate

200

A patient is breathing room air at sea level.

PaCO₂ = 32 mm Hg
PaO₂ = 72 mm Hg

What is the patient’s A-a gradient?

(Assume PB =760 mm Hg and PH2O =47 mm Hg)

37 mm Hg

PAO₂ = [0.21 × (760 − 47)] − (32/0.8)
PAO₂ ≈ 110 mm Hg

A-a gradient = 110 − 72 = 38 mm Hg

200

Ventilation that reaches alveoli that are not receiving pulmonary blood flow is described as what?

Dead space

200

What mode is this?

PC-SIMV

200

A 60-kg IBW patient with septic shock and severe lactic acidosis requires intubation due to worsening respiratory distress.

Before intubation:

RR: 30/min, HR: 102, BP: 108/56
ABG: pH 7.21 /PaCO₂ 24 /PaO₂ 68 /HCO₃ 10

What initial ventilator settings would you recommend?

VC 360, RR 30, +5-8, 100%

200

A patient with ARDS undergoes a PEEP titration, and optimal PEEP is identified at +14 cm H₂O. After the titration, the following values are obtained:

VT: 450 mL
RR: 20/min
Total PEEP: +14 cm H₂O
FiO₂: 0.50
Plateau pressure: 30 cm H₂O
SpO₂: 95%
Minute ventilation: 7.5 L/min

What ventilator adjustment would you recommend?

Decrease tidal volume and increase RR

200

A patient receiving VC/AC develops a high-pressure alarm. PIP has increased from 28 to 42 cm H₂O, while plateau pressure remains unchanged at 24 cm H₂O.

Name 3 possible causes of the high-pressure alarm.

Airway secretions
Bronchospasm
Kinked ETT
Patient biting the ETT
Water/obstruction in the ventilator circuit

200

A 67-year-old patient is admitted with several days of profuse diarrhea and worsening weakness. The patient is hypotensive but has already received appropriate fluid resuscitation. Laboratory values and ABG are:

pH: 7.16
PaCO₂: 27 mm Hg
PaO₂: 88 mm Hg
HCO₃⁻: 9 mEq/L

Na⁺: 136 mEq/L
Cl⁻: 118 mEq/L

What intervention would be most appropriate and why?

Administer bicarbonate

Anion gap:

AG = Na⁺ − (Cl⁻ + HCO₃⁻)

AG = 136 − (118 + 9)= 9

Normal anion gap metabolic acidosis, consistent with bicarbonate loss from diarrhea.

300

A patient with severe ARDS is receiving volume-controlled mechanical ventilation. The following data are obtained:

VT: 420 mL
FiO₂: 0.70
PEEP: 12 cm H₂O
Plateau pressure: 28 cm H₂O
Mean airway pressure: 16 cm H₂O
PaO₂: 70 mm Hg
PaCO₂: 42 mm Hg

What is the patient’s oxygenation index?

OI = (FiO₂ × Mean Airway Pressure × 100) / PaO₂

OI = (0.70 × 16 × 100) / 70

300

Which of the following is the consequence of increased resistance or compliance?

A. It takes less time to fill and empty the alveoli

B. It takes less time to fill and more time to empty the alveoli

C. It takes more time to fill but less time to empty the alveoli

D. It takes more time to fill and empty the alveoli

300

What type of asynchrony is this and how would you fix it?

Trigger asynchrony (failed/missed trigger)

Adjust sensitivity

300

A 75-kg IBW patient is intubated for acute hypoxemic respiratory failure secondary to pneumonia.

Before intubation:

RR: 28/min, HR: 98, BP: 134/67
SpO₂: 84% on NRB
ABG: pH 7.48 /PaCO₂ 31 /PaO₂ 52 /HCO₃ 23

What initial vent settings do you recommend?

VC 450, R-16, PEEP +8, 100%

VC 600 R-12, PEEP +8, 100%

300

Referring to the patient data below, the optimal PEEP level for this patient is:

+16

300

Name 3 signs that may indicate an endotracheal tube cuff leak.

Unable to maintain cuff pressure
Audible air leak
Decreased exhaled tidal volume
Low-pressure or low minute volume alarms

300

A patient is receiving APRV with the following settings:

PHigh: 28 cm H₂O
PLow: 0 cm H₂O
THigh: 4.0 sec
TLow: 0.5 sec
FiO₂: 0.40

ABG: pH: 7.48/ PaCO₂: 30 mm Hg/ PaO₂: 72 mm Hg

Name 2 APRV adjustments that could be made to correct the acid-base abnormality.

Decrease PHigh

Lengthen THigh

400

A mechanically ventilated patient has:

VT = 550 mL
RR = 12/min
VD/VT = 0.40

What is the patient’s alveolar ventilation?

3.96 L/min

Dead space = 550 × 0.40 = 220 mL

Alveolar volume per breath: 550 − 220 = 330 mL

Alveolar ventilation: 330 × 12 = 3,960 mL/min

400

A patient with extensive left-sided pneumonia is persistently hypoxemic. Which side should the patient lie on to maximize oxygenation?

Right side down

400

What mode is the patient in based on the flow volume loop and what are the trigger, limit, and cycle?

Volume control

trigger: patient/time

limit: flow/volume

cycle: volume/time

400

A 72-kg IBW patient following open-heart surgery is receiving VC/AC:
VT: 430 mL
Set RR: 16/min
Total RR: 24/min
PEEP: +5 cm H₂O
FiO₂: 0.40
PIP: 25 cm H₂O
Pplat: 21 cm H₂O
SpO₂: 97%
ABG: pH 7.27 / PaCO₂ 54 / PaO₂ 92 / HCO₃ 25
What ventilator change would you recommend?

Increase to 7ml/kg IBW: 505mL

400

Referring to the patient data below, the optimal PEEP level for this patient is:

+14

400

A patient receiving PC/AC develops copious airway secretions. Name 2 ventilator alarms you would expect to sound.

Low tidal volume alarm

Low minute ventilation alarm

400

A 66-year-old patient with severe ARDS and a predicted body weight of 68 kg is receiving volume-controlled ventilation with the following settings:

VT: 410 mL, RR: 22/min, PEEP: +16 cm H₂O, FiO₂: 0.60

Ventilator measurements:

PIP: 32 cm H₂O

Plateau pressure: 28 cm H₂O

Total PEEP: +16 cm H₂O

End-expiratory esophageal pressure: 9 cm H₂O

SpO₂: 96%

Which ventilator adjustment would you recommend based on the esophageal pressure measurements?

Decrease PEEP

End-expiratory transpulmonary pressure:

= 16 − 9 = +7 cm H₂O

Goal: 0 to +2

500

A patient is receiving 100% oxygen. The following values are obtained: Hb = 13 g/dL SaO₂ = 0.94 PaO₂ = 120 mm Hg SvO₂ = 0.72 PvO₂ = 38 mm Hg PaCO₂ = 36 mm Hg

What is the patient’s calculated shunt fraction?

(Hint: Assume PB = 760 mm Hg, PH2O =47 mm Hg, and Sc'O2 =1.0)

40%

500

Name 3 conditions that cause decreased lung compliance and 2 conditions that cause decreased thoracic compliance.

Decreased lung compliance: ARDS, pulmonary edema, pneumonia, pulmonary fibrosis, atelectasis

Decreased thoracic compliance: obesity, ascites, kyphoscoliosis

500

A patient is receiving VC/AC with:

VT: 400 mL, RR: 26/min, Flow: 52 L/min, decelerating waveform, PEEP: +5 cm H₂O, FiO₂: 0.40

Based on the flow-volume loop shown, identify the problem and name 3 ventilator adjustments that could help correct it.

Air trapping

Decrease respiratory rate
Increase inspiratory flow
Change the inspiratory flow waveform from decelerating to square

500

A 70-kg PBW patient with ARDS is receiving VC/AC ventilation with the following settings:
VT: 420 mL
RR: 24/min
PEEP: +10 cm H₂O
FiO₂: 0.60
Observed values:
PIP: 36 cm H₂O
Plateau pressure: 33 cm H₂O
SpO₂: 93%
ABG: pH 7.37 / PaCO₂ 40 / PaO₂ 68 / HCO₃⁻ 24
According to the ARDSNet protocol, what ventilator change is most appropriate?

Decrease tidal volume to 350 mL (5 ml/kg)

500

Describe what happened to compliance at each PEEP change:

8 --> 10 increased

10 --> 12 increased

12 --> 14 stayed the same

14 --> decreased

500

List 3 causes of ETCO₂ suddenly falling to zero

Cardiac arrest, apnea, ventilator/circuit disconnect.

500

A 64-year-old male with an IBW of 68 kg has severe ARDS with persistent hypoxemia despite prone positioning, inhaled nitric oxide, and neuromuscular blockade. The patient is cannulated for VV ECMO and is returning to the ICU.

What ventilator settings would you place the patient on?

PC-A/C, total pressure: 25 cm H2O, PEEP: 10 cm H2O, RR: 10, FiO2: 0.40