Monitoring the Anesthetized Patient - 2

Question 1

How to measure minute ventilation (V)?

Answer 1

TV (tidal volume) x frequency

Question 2

What is the end product of cellular metabolism?

Answer 2

CO2

Question 3

What is CO2 transported as in the venous system?

Answer 3

HCO3-

Question 4

The production and elimination of CO2 is linked to ____, perfusion, and _____.

Answer 4

The production and elimination of CO2 in linked to METABOLISM, perfusion, and VENTILATION.

Question 5

Capnography is a noninvasive method to measure systemic ____, ____, ____, and cardiac output.

Answer 5

Capnography is a noninvasive method to measure systemic METABOLISM, PULMONARY PERFUSION, PULMONARY VENTILATION, and cardiac output.

Question 6

If CO2 production (metabolism), cardiac output, and pulmonary perfusion are all constant, but there is a change in the End-tital CO2, what caused the change?

Answer 6

A change in ventiation

Question 7

EtCO2 monitors exhaled CO2 noninvasively and is an indirect measurement of ____ CO2.

Answer 7

Arterial CO2 (PaCO2)

Question 8

EtCO2 will be ____ mmHg less than PaCO2.

Answer 8

3 - 5

Question 9

What is the most useful value for detection of apnea and hypoventilation?

Answer 9

EtCO2

Question 10

What are the advantages of a sidestream capnography sampling tube?

Answer 10

1. Light weight
2. Ease of manipulation
3. Ability sample other gases
4. Small sample chamber

Question 11

What are the disadvantages of a sidestream capnography sampling tube?

Answer 11

1. Need to scavenge aspirated gases
2. Plugging of sample line by secretions
3. 2-3 second delay
4. Dilution of sample from leaks in breathing circuit

Question 12

What are the advantages of a mainstream capnography sampling tube?

Answer 12

1. No scavenging of aspirated gases needed

2. Real-time measurement

Question 13

What are the disadvantages of a mainstream capnography sampling tube?

Answer 13

1. Added dead space
2. Weight can cause kinking of the ET tube
3. Sensing chamber can be contaminated by secretions
4. Patients may be burned by heated cuvette (sensors are heated to prevent condensation of water vapor)

Question 14

What are 5 specific causes of increased EtCO2 values?

Answer 14

1. Metabolism : fever, malignant hyperthermia
2. Pulmonary perfusion : increased CO, increased BP
3. Alveolar ventilation : hypoventilation, rebreathing
4. Technical errors : exhausted soda lime, faulty one-way valves, inadequate fresh gas flow

Question 15

What are 5 specific causes of decreased EtCO2 values?

Answer 15

1. Metabolism : hypothermia, hypothyroidism, muscle relaxants
2. Pulmonary perfusion : decreased CO, decreased BP, cardiac arrest, pulmonary embolism
3. Alveolar ventilation : hyperventilation, apnea, partial esophageal obstruction
4. Technical error : leak in sample line, patient disconnect, high FGF in NRB system

Question 16

What is the typically difference between EtCO2 and PaCO2 in a horse?

Answer 16

EtCO2 ~ 10-15 mmHg

Question 17

What is normal blood pH?

Answer 17

7.4

Question 18

What do you call an increased PaCO2?

Answer 18

Respiratory acidosis

Question 19

What do you call a decreased PaCO2?

Answer 19

Respiratory alkalosis

Question 20

What do you call an increased HCO3-?

Answer 20

Metabolic alkalosis

Question 21

What is PaCO2?

Answer 21

The partial pressure of CO2 in arterial blood

Question 22

Would a decreased PaCO2 likely be associated with hyperventilation or hypoventilation?

Answer 22

Hyperventilation

Question 23

Based on the side effects of many of the drugs we give patients for anesthesia, would you most commonly see an increase or decrease in PaCO2?

Answer 23

Increased PaCO2

Question 24

What is PaCO2 in a normal, awake patient?

Answer 24

35 - 45 mmHg

Question 25

What value will tell the TRUE PaCO2 - EtCO2 difference?

Answer 25

ABG (arterial blood gas)

Question 26

What are 3 causes of dark pink mucous membranes?

Answer 26

1. Vasodilation 2. Endotoxemia 3. Increased CO2

Question 27

There are 5 factors that can affect the function and accuracy of a pulse oximeter. Name 3.

Answer 27

1. Movement artifact 2. Dark mucous membranes 3. Fluorescent light 4. Poor peripheral blood flow (hypotension) 5. Increased carboxyhemoglobin and methemoglobin levels

Question 28

Pulse oximetry is most helpful when patients are __1__ or __2__.

Answer 28

1. Breathing room air | 2. Transitioning (induction, recovery)

Question 29

What is an ideal SpO2?

Answer 29

> 93-95 %

Question 30

What is a normal PaO2 in room air?

Answer 30

90-100 mmHg

Question 31

A normal PaO2 in patients breathing 100% oxygen should be what?

Answer 31

> 250-650 mmHg

Question 32

There are 5 consequences of hypothermia. Name 3.

Answer 32

1. Decreased MAC 2. Impaired platelet function 3. Decreased coagulation 4. Impaired wound healing 5. Increased risk of surgical infection

Question 33

What are the consequences of hyperthermia?

Answer 33

1. Increased circulatory work 2. Cellular hypoxia 3. Increased metabolic rate

Question 34

How would you treat hyperthermia? (Name 2)

Answer 34

1. Active cooling | 2. Supplement with O2

Question 35

What is the purpose of the demand valve for large animals?

Answer 35

Demand valve delivers intermittent positive pressure ventilation

Question 36

What volume of oxygen does the demand valve deliver each minute?

Answer 36

200 L/min

Question 37

There are multiple indications for the use of the demand valve. What are 3 of those indications?

Answer 37

1. Apnea 2. Head trauma 3. Significant hypoventilation 4. Intra-thoracic surgery 5. Horse anesthesia 6. Use of neuromuscular blocking agents

Question 38

What does the bellow take the place of in the breathing circuit?

Answer 38

Reservoir bag

Question 39

Which animals do you NOT wean from IPPV? What is the exception?

Answer 39

Do not wean horses, except in brain cases (head trauma, tumor, etc.)

Question 40

What 2 steps are involved in weaning a patient from IPPV?

Answer 40

1. Lower the respiratory rate to increase PaCo2 | 2. Discontinue the inhalant to decrease CO2 set point in the brain