PreTest Surgery: Critical Care: Anesthesiology, Blood Gases, and Respiratory Care

Question 1

Describe the criteria for successful extubation.

Answer 1

• Correction of the underlying pathology
• Hemodynamic stability
• Rapid shallow breathing index (the ratio of respiratory rate to tidal volume) between 60 and 105
• Negative inspiratory force greater than - 20 cm H2O
• Weaned to 5 cm PEEP
• Spontaneous breathing less than 20

Question 2

____________ should not given to those with air-trapping pathologies because it is less dense than air and can get trapped in those cavities.

Answer 2

Nitrous oxide

Avoid this in those with SBO and pneumothorax.

Question 3

List the criteria for diagnosis of ARDS.

Answer 3

• PaO2/FiO2 less than 200
• Bilateral chest infiltrates
• PCWP less than 18

Question 4

What conditions cause a right-shift in the oxygen-dissociation curve?

Answer 4

A right shift means that oxygen is offloaded more easily:

• Acidosis
• Increased temperature
• Increased BPG

Question 5

Explain the dosing tiers of dopamine.

Answer 5

• Low-dose: dilates the renal and mesenteric vasculature which increases perfusion
• Medium-dose: inotrope
• High-dose: increases SVR

Question 6

A patient receives plasma and then becomes hypoxemic. What happened?

Answer 6

TRALI: transfusion-related acute lung injury

To treat this, stop the transfusion and intubate.

Question 7

True or false: give dobutamine to those with cardiogenic heart failure and signs of myocardial ischemia.

Answer 7

True

Because dobutamine primarily affects inotropy and not chronotropy, it only moderately increases myocardial oxygen demand.

Question 8

The proper treatment for acalculous cholecystitis is _______________.

Answer 8

percutaneous drainage

Question 9

PEEP affects which lung capacity?

Answer 9

It increases FRC. In ARDS, alveoli close and thus decrease the ERV. PEEP keeps the alveoli open and increases ERV (and thus FRC).

Question 10

In cardiac tamponade, what might Swan-Ganz catheterization show?

Answer 10

Equalization of pressures across all four chambers

Question 11

Risk of a cardiac event during a surgery is given by major, intermediate, and mild factors. List some of each.

Answer 11

•Major:

• Unstable angina
• Recent MI (less than 6 months)
• Decompensated CHF
• Severe valvular disease
• Significant arrhythmias

•Intermediate:

• Diabetes
• Mild angina
• Compensated CHF
• Renal insufficiency

• Minor:

• Advanced age
• Abnormal EKG
• Prior CVA
• Uncontrolled HTN

Question 12

What BP and HR pattern is characteristic of neurogenic shock?

Answer 12

Hypotension and bradycardia

Neurogenic injury (such as spinal trauma) causes a loss of sympathetic input to the vessels and thus a lowering of BP. The heart normally increases in hypotensive states, but that pathway is also through the spine so is lost.

Question 13

How do you treat neurogenic shock?

Answer 13

1) Fluid bolus

2) Phenylephrine or dopamine

Question 14

If you suspect air embolism in a central line, you should first ________________.

Answer 14

place the patient in a left-lateral decubitus, Trendelenburg position (so that the bubble won’t travel to the brain)

Question 15

According to PreTest, what is the treatment algorithm for anaphylaxis?

Answer 15

In a conscious patient:

1) Epinephrine (injected or inhaled)
2) Antihistamines

In an unconscious patient or someone with refractory hypotension:

1) Intubate
2) Epinephrine (injected)

I’ve read intubate first in other areas.

Question 16

List the diagnostic criteria for immediate hemolytic transfusion reaction.

Answer 16

• Positive Coombs test
• Myoglobinuria
• Haptoglobin less than 50

Question 17

What lab test may be an even better indicator of nutritional status than albumin?

Answer 17

Prealbumin

It has a shorter half-life and thus can detect acute nutritional shortages.

Question 18

Explain respiratory quotient.

Answer 18

RQ is the ratio of CO2 production to O2 intake. It is an indicator of nutritional status in relation to ventilation status.

A ratio of 0.75 to 0.85 is ideal. A ratio of 1 indicates a high carbohydrate diet that may make weaning from ventilation difficult.

Question 19

A patient has minor bleeding from a tracheostomy placed a couple days prior. What could this be and how should you manage it?

Answer 19

A tracheo-innominate artery fistula (called a sentinel bleed)

Because of the seriousness of this condition, examination in the OR with a bronchoscope is the safest option.

Question 20

A patient with severe von Willebrand is having elective surgery. What should you give them beforehand?

Answer 20

Cryoprecipitate

Question 21

A patient has obvious gastric contents in their pharyngeal area after an MVC. How should you manage this?

Answer 21

Bronchoscopy for removal of particulate matter

Question 22

What is the diagnostic finding of ventilator-associated pneumonia?

Answer 22

> 10,000 CFUs/mL in bronchoalveolar lavage

Question 23

How do you immediately treat malignant hyperthermia?

Answer 23

• Stop the operation
• Stop the anesthesia
• Hyperventilate with 100% O2
• Treat with IV dantrolene

Question 24

List some things that increase and decrease CVP.

Answer 24

Increase:

• PPV
• Pneumothorax with mediastinal compression
• Vasoconstricting agents (phenylephrine)
• PE

Decrease:

• Hypovolemia
• Sepsis
• Anaphylaxis
• Neurogenic shock

Question 25

Aortic angiography can result in what pathology that presents with eosinophilia, acute renal failure, and elevated ESR?

Answer 25

Cholesterol embolism to the renal arteries

Question 26

After a surgery, a patient with a recent complex medical history develops nausea, vomiting, orthostatic hypotension, and fever. What endocrine problem might this be?

Answer 26

Adrenal insufficiency

Those who are sick already can sometimes develop adrenal insufficiency with the stress of surgery.

Question 27

Signs of necrotizing wounds –enlarging erythema, blistering drainage –warrant ___________.

Answer 27

wide debridement

Question 28

How can CVP help direct your efforts at diagnosing and correcting hypotension?

Answer 28

CVP will be low in hypovolemic states and normal in vasoplegiac states (like sepsis, anaphylaxis), so if the CVP is low you bolus fluids and if it is normal go for norepinephrine.

Question 29

What kind of catheter would you want in a patient getting inotropic agents for cardiogenic shock?

Answer 29

A pulmonary heart catheter

The big question is “does this patient’s heart need inotropes?” You can answer that with a pulmonary catheter by titrating down the inotropes and seeing if the RV is able to pump on its own.

Question 30

What does thrombin time measure?

Answer 30

Fibrinogen quality/quantity

An active thrombin is added to a pool of patient’s plasma. The rate-limiting factor is fibrinogen.