Exam 2 Basics Of Breathing

Front 1

dead space

Back 1

1. part of a tidal volume that does not undergo alveolar ventilation
2 circle system is limited to the area distal to the point of inspiratory and expiratory gas mixing at the Y-piece.

Front 2

causes an increase in dead space

Back 2

1. malfunctioning unidirectional valve will increase circuit dead space and allow rebreathing of expired CO2.
2. Humidifiers
3.ventilation lost to expansion of the breathing circuit
during positive-pressure ventilation.
4. Physiologic due to mismatch in V/Q

Front 3

What is added from the alveoli
3

Back 3

Carbon dioxide
Water vapor
Gases from the body (methane, acetone, N2)

Front 4

Breathing Circuit Should allow rebreathing of

Back 4

Oxygen not metabolized
Nitrous oxide or air
Anesthetic agent

Front 5

Nitrous oxide increases (respiratory related)

Back 5

increases respiratory rate (tachypnea) and decreases tidal volume as a result of central
nervous system stimulation and, perhaps, activation of pulmonary stretch receptors. The net effect is a
minimal change in minute ventilation and resting arterial CO2 levels.

Front 6

Hypoxic drive, the ventilatory response
to arterial hypoxia that is mediated by

Back 6

peripheral chemoreceptors in the carotid bodies, is markedly
depressed by even small amounts of nitrous oxide.

Front 7

basic breathing rhythm originates in

Back 7

in the medulla.

Front 8

4 areas that control breathing

Back 8

central respiratory center
peripheral chemoreceptors
lung receptors
effects of anesthesia

Front 9

areas influence the dorsal (inspiratory) medullary center

Back 9

Two pontine areas,
A lower pontine (apneustic) center
is excitatory, whereas an upper pontine (pneumotaxic) center is inhibitory. The pontine centers appear to fine tune
respiratory rate and rhythm.

Front 10

Central chemoreceptors (Central Respiratory Centers) are thought to lie on

Back 10

anterolateral surface of the medulla and
respond primarily to changes in cerebrospinal fluid (CSF) [H+].

Front 11

the principal peripheral
chemoreceptors in humans

Back 11

The carotid bodies
are sensitive to changes in PaO2, PaCO2, pH, and arterial perfusion pressure

Front 12

the carotid bodies interact with central respiratory centers via the

Back 12

glossopharyngeal nerves, producing reflex increases in
alveolar ventilation in response to reductions in PaO2, arterial perfusion, or elevations in [H+] and PaCO2.

Front 13

Hypoxic drive, the ventilatory response
to arterial hypoxia that is mediated by

Back 13

peripheral chemoreceptors in the carotid bodies, is markedly
depressed by even small amounts of nitrous oxide.

Front 14

Lung Receptors

Back 14

Impulses from these receptors are carried centrally by the vagus nerve. Stretch receptors are distributed in the smooth muscle of airways; they are responsible for inhibition of inspiration when the lung is inflated to excessive volumes (Hering–Breuer inflation reflex) and shortening of exhalation when the lung is deflated
(deflation reflex).

Front 15

(Hering–Breuer inflation reflex

Back 15

they are responsible for inhibition of inspiration when the lung is inflated to
excessive volumes

Front 16

functional residual capacity (FRC).

Back 16

lung volume at the end of a normal exhalation

Front 17

Induction of anesthesia (and FRC)

Back 17

consistently produces an additional 15–20% reduction in FRC (400 ml in most
patients) beyond what occurs with the supine position alone.

Front 18

Central chemoreceptors are thought to lie on

Back 18

the anterolateral surface of the medulla and respond
primarily to changes in cerebrospinal fluid [H+]. This mechanism is effective in regulating PaCO2, because the
blood–brain barrier is permeable to dissolved CO2 but not to bicarbonate ions.

Front 19

principal function of the lungs is to allow

Back 19

gas exchange between blood and inspired air.

Front 20

Hypercarbia is often associated

Back 20

with
hypertension.

Front 21

if lash reflex abolished then

Back 21

eyelid reflex diminished

Front 22

Inhalation agents lower

Back 22

lower tidal volumes
increase respiratory rate

Front 23

Limbic System Stimulation 3 points

Back 23

Anticipation of activity
Emotional anxiety
Increases rate and depth of ventilation

Front 24

temperature and ventilation
4 points

Back 24

Increased temperature increases respiratory rate
Decreased temperature decreases respiratory rate
Controlled ventilation recommended for febrile patient
Controlled ventilation recommended for cold patient

Front 25

Pain and apnea
3 points

Back 25

Sudden severe pain causes apnea
Prolonged somatic pain increases respiratory rate
Visceral pain decreases respiratory rate (deep abdominal pain)

Front 26

Stretching the Anal Sphincter
4 points

Back 26

Stimulates respiration
Consider intubating these cases
Frequent episode laryngospasm
Watch the surgeon and have patient deep

Front 27

general rule with intubation

Back 27

do not want alot of stim
Take patient through Stage II gently or IV induction

Front 28

respiration
Sudden rise in blood pressure

Back 28

decreases respiration

Front 29

respiration
Sudden drop in blood pressure

Back 29

increases respiration

Front 30

Pleural cavity pressure always

Back 30

subatmospheric

Front 31

Diaphragm
2 points

Back 31

Skeletal muscle
Innervated from phrenic nerve C 3-4-5

Front 32

Diffusing capacity for hemoglobin

Back 32

Volume of a gas that diffused through membrane each minute for a pressure difference of 1 mmHg
Normally 21 ml/min/mmHg
Mean oxygen pressure difference = 11 mmHg
21 ml/min/mmHg X 11 mmHg = 230 ml/min

Front 33

Basal metabolic oxygen consumption ( VO2) equals

Back 33

10 times a patient's weight in kilograms to
the three-quarters power:

Front 34

Oxygen requirements decrease by 10%

Back 34

for each degree below 37.6°C:

Front 35

Increasing depth of anesthesia does not significantly alter basal metabolic rate

Back 35

unless tissue perfusion is compromised.

Front 36

Tidal volume = (formula)

Back 36

500 ml or 7 cc/kg IBW
70% of TV reaches alveoli
30% does not-anatomic dead space

Front 37

Forceful exhalation =

Back 37

expiratory reserve volume
Residual volume left over

Front 38

Functional residual capacity

Back 38

The lung volume at the end of a normal exhalation
(expiratory reserve volume +
Residual volume)

Stays in lungs at end expiration

Front 39

Alveolar Ventilation =

Back 39

Total volume of new gas entering each minute
AV = RR x (TV – dead space)

Front 40

Alveolar gas consists

Back 40

Fresh gas - metabolized gas
Carbon dioxide
Water vapor

Front 41

Slow Replacement of Alveolar Air?

Back 41

Prevents sudden changes in gas concentration
Respiratory control more stable

Front 42

transport protein

Back 42

albumin

Front 43

goal blood pressure

Back 43

20% of norm

Front 44

Ventilation not necessary for ______, but necessary for removal ______.

Back 44

oxygenation, CO2

High solubility necessitates removal

Front 45

CO2 produced dictates

Back 45

dictates minute ventilation

i.e. Cardiopulmonary bypass (low levels)
ECMO only exceptions

Front 46

Spontaneous breathing keeps PCO2
(can be affected by 3X)

Back 46

PCO2 - 40mmHg

Absence of disease (copd, smoker)
High altitude and
Pharmacologic intervention

Front 47

Carbon Dioxide Production
Resting adult produces

Back 47

.008 gm molecules/min

Front 48

In the open system, the patient

Back 48

inhales only the mixture
delivered by the anesthesia machine. Valves direct
each exhaled breath into atmosphere. A reservoir bag
mayor may not be present. Rebreathing is minimal, and
there is no carbon dioxide absorption.

Front 49

In the semiopen system,

Back 49

exhaled gases flow out of the
system and to the inspiratory line of the apparatus to be
rebreathed. There is no chemical absorption of carbon
dioxide. Rebreathing depends on the fresh gas flow. A
reservoir bag and a directional valve are optional.

Front 50

In the semi-closed system,

Back 50

part of the exhaled gases
passes into atmosphere and part mixes with fresh gases
and is rebreathed. Chemical absorption of carbon dioxide,
directional valves, and a reservoir bag are present

Front 51

In the closed system,

Back 51

there is complete rebreathing
of expired gas. Carbon dioxide absorption, a reservoir
bag, and directional valves are present.

Front 52

Open circuit

reservoir?
rebreathing?
example?

Back 52

reservoir? no
rebreathing? no
example? open drop, insufflation, nasal cannula

Front 53

Semiopen
reservoir?
rebreathing?
example?

Back 53

reservoir? Yes
rebreathing? no
example? nonrebreathing circuit or a circle at high fresh gas flows

Front 54

Semiclosed
reservoir?
rebreathing?
example?

Back 54

reservoir?Yes
rebreathing? Yes(partial)
example? circle at fresh gas flow less that minute ventilation

Front 55

Closed
reservoir?
rebreathing?
example?

Back 55

reservoir?Yes
rebreathing? Yes complete
example? circle at extremely low fresh gas flow with a adjustable pressure limiting valve closed

Front 56

(open) insufflation system is one in which gases are
5 points

Back 56

1. (blowing of gases across a patients face.
2 no contact airway or breathing circuit.
3. valuable with pediatric anesthesia
4. no rebreathing of exhaled gases if high flows are used.
5. ventilation not controlled.

gases are delivered directly into the patient's airway. There are no valves, reservoir bag, or carbon dioxide absorption.

Front 57

insufflation usually denotes

Back 57

the blowing of anesthetic gases across a patient's face.

Front 58

open-drop anesthesia

Back 58

highly volatile anesthetic, halothane—is dripped onto a gauze covered mask (Schimmelbusch mask) applied to the patient's face. As the patient inhales, air passes through the gauze, vaporizes the liquid agent, and carries high concentrations of anesthetic to the patient. (rebreathing may be significant)

Front 59

4 Disadvantages of Open

Back 59

poor control of inspired gas concentration and depth of anesthesia
inability to assist or control ventilation
no conservation of exhaled heat or humidity
pollution of OR with large volumes of waste gases

Front 60

Draw-over anesthesia 5 points

Back 60

1 nonrebreathing circuits that use ambient air as carrier gas
2 can use supplemental O2
3 inspired vapor and O2 concentrations are predictable and controllable
4 allow IPPV and passive scavenging
5 allow CPAP and PEEP
6 low resistance vaporizers
7 never use N2O
8 may have low O2 saturation with room air

Front 61

Draw-over anesthesia pro and con

Back 61

advantage: simple and portable

disadvantages: depth of TV not well known due to no rebreathing bag; awkward to use for ENT/head surgery due to components located near patient’s head

Front 62

used to prevent rebreathing of CO2

Back 62

high FGF’s

Front 63

3 performance characteristics of Mapleson

Back 63

1 lightweight, inexpensive and simple
2 some rebreathing occurs (flow controls amount)
3 allow quick change in anesthetic concentration due to high FGF (key)

Front 64

Mapleson_____ best for spontaneous ventilation

Back 64

A

Front 65

Mapleson ____ best for controlled ventilation

Back 65

D

Front 66

Bain circuit is modification of_____

Back 66

D

Front 67

Mapleson best for Spontaneous ventilation __ __ __ __

Back 67

(A, D, F, E )

Front 68

Mapleson best for controlled ventilation ___ ___ ___ ___

Back 68

(D, F, E, B, C )

Front 69

6 Advantages of Mapleson system

Back 69

Low resistance to breathing made them popular in pediatrics
Less work of breathing
Simple, portable
Easy to assemble
Minimal moving parts
Some retention heat & humidity

Front 70

6 Disadvantages of Mapleson

Back 70

Most advantages overshadowed by need for high flow rates
Costs
Dry & cold airway
OR pollution
Difficult to change from spontaneous to controlled ventilation
Has led to many ‘modifications’ of Mapleson systems for modern use

Front 71

Back 71

mapleson A, best for spontaneous

Front 72

Back 72

mapleson B

Front 73

Back 73

Mapleson C

Front 74

Back 74

Mapleson D (Bain)

Front 75

Back 75

mapleson E

Front 76

Back 76

mapleson F

Front 77

Mapleson A system differs from the other Mapleson
systems in that

Back 77

fresh gas does not enter the system near
the patient connection but enters at the other end of the system near the reservoir bag.

Front 78

The Mapleson B system the
fresh gas inlet and APL valve are both located near

Back 78

patient port.

Front 79

The Mapleson C system is identical to X except

Back 79

except that the corrugated tubing is omitted

Front 80

The Mapleson D system is popular because

Back 80

excess gas scavenging is relatively easy, and it is the most efficient of the Mapleson systems during controlled ventilation.

Front 81

Mapleson D system and peep

Back 81

A bidirectional positive end-expiratory pressure
(PEEP) valve may be placed between the corrugated tubing
and the APL valve

Front 82

In the Bain modification

Back 82

the fresh gas supply
tube runs coaxially inside the corrugated tubing and
ends at the point where the fresh gas would enter if the
classic Mapleson D form were used

Front 83

Bain System Hazards

Back 83

inner tube of the Bain system becomes detached
from its connections at either end or develops a leak at
the machine end, if the fresh gas supply tube becomes
kinked or twisted

Front 84

Semi-closed (Circle System)
5 points

Back 84

Most commonly used
Adults and pediatrics
More complex but more efficient than Mapleson
Prevents rebreathing of CO2
Allows use of low flows

Front 85

Back 85

circle system with APL,

Front 86

3 keys of closed system to prevent rebreathing

Back 86

valve must be between patient and rebreathing bag on both inspir/expir limbs
FGF cannot enter circuit between expir. valve and patient
APL cannot be located between patient and inspir. valve

Front 87

6 Valve ASTM Requirements

Back 87

Flow direction shall be permanently marked
Functioning of valves should be visible
Resistance of dry & moist valves shall not exceed a pressure drop of 0.15 kPa (1.5cmH2O) at 1L/second flow (60L/min-test flowrate for adults)
Opening pressure of moist valve should not exceed 0.15 kPa (1.5cmH2O)
Reverse flow shall not exceed 60mL/min at any pressure differential to 0.5 kPa (5cmH2O)
Determined to be clinically acceptable & detectable with currently available volume monitors
Valve shall not become dislocated with a reversed pressure differential of 5 kPa (50cmH2O)
Maximum pressure in bag mode of circle system

Front 88

Malfunction of either valve may allow (3 things)

Back 88

1. rebreathing of CO2, resulting in hypercapia
2. Faulty valve can lead to increased PIP’s or increased ETCO2 with elevated baseline on waveform
3. Increased resistance

Front 89

Incompetent Expiratory Valve

Back 89

Capnograph shows ‘elevated baseline’
Baseline should always return to zero if you have no re-breathing
Re-breathing occurring on expiratory limb of waveform
Anatomic dead space exhaled at baseline
Also look at inspired CO2 numeric – FiCO2

Front 90

Incompetent Inspiratory Valve

Back 90

Capnograph shows abnormal ‘beta angle’
Normal beta angle approximately 90°
Re-breathing occurring during inspiration
Shows on inspiratory side of waveform
Shaded area represents approximately 180° beta

Front 91

Obstruction to Gas Flow

Back 91

Disc damaged and jams valve seat
Disc lost during cleaning & not recovered
Migrated down into bag mount or vent hose
Functioned as one-way valve
Gas could flow into circuit & patient
Gas could not flow out
Bilateral tension pneumothorax

Front 92

FDA Checkout 12.1:

Back 92

Check for proper action of the unidirectional valves

Front 93

Tubes of Breathing Circuit internal volume

Back 93

400-500ml per meter

Front 94

Always test circuit before using by determining oxygen flow required to maintain

Back 94

30 cm H2O pressure in circuit

Front 95

Dead space is

Back 95

1. space in circuit occupied by gases that are rebreathed without any change in composition
2 Part of TV that doesn’t undergo alveolar ventilation
3 Dead space begins at Y piece and extends to any adapters distal to Y piece (distal limb of Y piece and any ETT or mask between it and patient’s airway)
NOT at end of breathing circuit

Front 96

Common (Fresh) Gas Outlet

Back 96

only one outlet that supplies gas to the circuit
adds new gas of fixed and known composition
has anti-disconnect device used to prevent detachment of hose
usually latex-free
oxygen flush valve provides O2 to common gas outlet

Front 97

Fresh Gas Inlet
3 points

Back 97

1 gases (anesthetics with oxygen/air/nitrous) from the machine continuously enter the circuit through this inlet
2 placed between absorber and inspiratory valve
3 connected with flexible rubber tubing (delivery hose)

Front 98

Reservoir bag
6 points

Back 98

attached to bag mount
3 functions
reservoir for anesthetic gases from which patient can inspire
provide visual/tactile means of existence and of volume of ventilation
serve as means for manual ventilation
usually elliptical in shape
nonslippery plastic or latex rubber
sizes from 0.5 to 6L
3 L bag is usually sufficient for most adults
****think of breathing bag as patient’s lungs

Front 99

If high pressure alarm

Back 99

disconnect patient from vent and bag till you find out what is wrong