Test 2: 20 +21

Question 1

respiratory arrest happen at — MAC

Answer 1

2-3 x increase

Question 2

MAC at 1=

Answer 2

50% of patients will be properaly anesthetized

resp arrest at 2-3 MAC
cardiac arrest at 4-5 MAC

Question 3

— coordinates the transition between inhalation and exhalation; it also prevents overinflation of the lungs by always sending inhibitory impulses to the inspiratory center

Answer 3

pneumotaxic center

Question 4

the pneumotaxic center prevents — of the lungs by always sending — impulses to the inspiratory center

Answer 4

overinflation
inhibitory

Question 5

— coordinates the transition between inhalation and exhalation by fine-tuning the medullary respiratory centers; does this by sending — impulses to the inspiratory center which result in a slower, deeper inhalation; this is necessary when you choose to —

Answer 5

apneustic center

stimulatory

hold your breath

Question 6

two major centers of the pons

Answer 6

pneumotaxic center: this is the regulator; it coordinates the transition between inhalation and exhalation; it also prevents overinflation of the lungs by always sending inhibitory impulses to the inspiratory center

apneustic center: coordinates the transition between inhalation and exhalation by fine-tuning the medullary respiratory centers; does this by sending stimulatory impulses to the inspiratory center which result in a slower, deeper inhalation; this is necessary when you choose to hold your breath

Question 7

what groups are in the medullary respiratory center

Answer 7

Dorsal respiratory group
ventral respiratory group

Question 8

ventral respiratory group does

Answer 8

only activated when demand is high and is involved in forced inspiration and expiration.

medullary respiratory center: dorsal and ventral respiratory groups →control the phrenic nerve and the intercostal nerves.

Question 9

Dorsal respiratory group does

Answer 9

responsible for stimulating inhalation, thought to set by basic rhythm “pacemaking” and exciting the inspiratory muscles

medullary respiratory center: dorsal and ventral respiratory groups →control the phrenic nerve and the intercostal nerves.

Question 10

—: dorsal and ventral respiratory groups →control the phrenic nerve and the intercostal nerves.

Answer 10

medullary respiratory center

Question 11

If anesthesia impairs the ventilator centers and the ventilation, this can lead to a — in oxygen uptake and an — of CO2 due to reduced exhalation

Answer 11

reduction

accumulation

Question 12

CO2 and O2 receptors in the aorta trigger signal to the — that cause —

Answer 12

↑CO2 causes decrease in pH of blood

brain (pons and medulla)

triggers signal to the diaphragm and intercostal muscle to contract and inhale

Question 13

reduced oxygen uptake can cause

Answer 13

hypoxemia
hypoxia

Question 14

reduced CO2 exhalation will cause what

Answer 14

acid base disturbances → ↑CO2 will cause ↓ in pH of blood (respiratory acidosis)

central damping

Question 15

how to calculate minute ventilation

Answer 15

tidal volume x RR

during anesthesia tidal volume may decrease and RR will increase to compensate

Question 16

The most accurate way of measuring respiratory volumes is using a —.

Answer 16

spirometer

Question 17

what is a spirometer

Answer 17

This is an apparatus for measuring the volume of air inspired and expired by the lungs

most accurate way of measuring respiratory volumes

rarely used in hospital setting

Question 18

in general tidal volume equation

Answer 18

10 ml/kg

10x (30 kg dog)= 300 ml tidal volume

Question 19

average bag size for animal

Answer 19

weight in kg/10

10 kg pt/10= 1 L bag

bags only go up to 30L used for horses >500kg

Question 20

Answer 20

pitot tube

spirometer: measures the volume of air inspired and expired by the lungs by measuring the pressure gradient

Question 21

Answer 21

wrights spirometer

spirometer: measures the volume of expired air by the lungs by counting spins

Question 22

ETCO2 is a measure of

Answer 22

expiratory CO2 concentration which is an indicator for the arterial CO2 concentration

Question 23

capnography measures

Answer 23

expiratory CO2 concentration which is an indicator for arterial CO2 concentration

Question 24

Science behind capnography

Answer 24

Capnographs usually work on the principle that CO2 absorbs infrared radiation. A beam of infrared light is passed across the gas sample to fall on a sensor. The presence of CO2 in the gas leads to a reduction in the amount of light falling on the sensor, which changes the voltage in a circuit. The analysis is rapid and accurate.

measure expiratory CO2 concentration

Question 25

Answer 25

Question 26

main stream vs side stream capnography

Answer 26

main stream: directly from the airway, very accurate, breaks easily, $$, human sized

side stream: analysis done away from pt, delay (12-15sec), only sample small amount of air- not as accurate

measure CO2 levels

Question 27

The ETCO2 should be maintained between — mmHg.

Answer 27

35 and 45

Question 28

An ETCO2 — mmHg is considered hyperventilation and an ETCO2 — mmHg is considered hypoventilation

Answer 28

below 30
greater 60

should be kept 35-45 mmHg

Question 29

capnography but pt breathing

Answer 29

tube in esophagus

need to take out and reintubate

Question 30

Answer 30

slow inspiration with cardiogenic ripples

very light animals-
slow RR
high muscle tone

pumping of heart pushes on lungs and cause tiny exhales of CO2

Question 31

Answer 31

leak

Question 32

Answer 32

valve defect
water in system

Question 33

Answer 33

CO2 rebreathing

CO2 scrubber (sodalime) not working- old- needs to be replaced

Question 34

Answer 34

very slow exhale- do not get to platuea before pt inhales

Obstruction (Tube, Bronchus)

Question 35

Answer 35

lung not well profused, getting less O2= less CO2 transfer

cardiac arrest

Question 36

Hypoventilation leading to — ETCO2-values is relatively common during general anesthesia because of the respiratory depressant effects of most anesthetics.

Answer 36

high (>60mmHg)

Question 37

Positive effects of hypoventilation induced — are stimulation of ventilation through both central and peripheral chemoreceptors, stimulation of the sympathetic nervous system resulting in an — in heart rate and blood pressure, and peripheral — by direct effect on vessels.

Answer 37

hypercapnia

increase

vasodilation

Question 38

severe hypercapnia can lead to cerebral — increasing cerebral blood flow and intracranial pressure (only a problem with patients with high ICP) but also to central depression at very — levels of PaCO2 leading to prolong and unpredictable recovery periods.

Answer 38

vasodilation

high

Question 39

The best and most accurate way of assessing ventilation

Answer 39

blood gas analysis

arterial partial pressure of carbon dioxide (PaCO2)

can only use a few times, need bigger pt, can be expensive to test

Question 40

E TCO2 < 30 mmHg means

Answer 40

Hyperventilation
* Rare under anesthesia when spontaneously ventilating
* Uncommon, but feasible when mechanically ventilating

Low cardiac output
* Decrease in CO2 production
* Decrease in blood flow

Question 41

E TCO2 > 60 mmHg is caused by

Answer 41

Hypoventilation
* Very common with inhalant anesthetic

need to mechanically or hand ventilate pt

Question 42

why do you need to address hypercapnea

Answer 42

• can cause acid-base imbalance (↑CO2= ↓ph)
• high levels can effect mental status (central depression)
• can cause hypoxemia, too much CO2 in alveoli →no room for O2 to come in
• ↑ SYM= ↑HR and HTN
• peripheral vasodilation
• cerebral vasodilation → ↑ ICP

Question 43

3 ways to assess ventilation

Answer 43

count RR and estimate tidal volume to calculate minute ventilation

capnography- EtCO2

arterial blood gas- PaCO2

Question 44

cardiac output is — to the respiratory ventilation

Answer 44

=

blood comes in at a rate = to the rate of gas exchange in the lungs