Module 8 Flashcards

1
Q

Which gases are important to the anesthesia provider

A

O2

CO2

NO

Inhaled Anesthetics

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2
Q

Gas sampling systems can be

A

Diverting or Non-diverting

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3
Q

Non diverting systems are

A

Mainstream

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4
Q

Diverting systems are

A

Side-stream (most used)

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5
Q

What is it called when the analyzer is located in the breathing system

A

Called non-diverting because the gas isn’t removed from the circuit (continuously analyzed)

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6
Q

The overall response time is

A

Composer of transit time & rise time

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7
Q

What is transit time?

A

Time it takes for gas sample to reach analyzer

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8
Q

What is rise time?

A

Time it takes for analyzer to reach a change in gas composition

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9
Q

The response of diverting or side stream system is dependent upon

A

The sampling tube inner diameter, the linked & gas sampling rate

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10
Q

In mainstream or non diverting systems, gas flows

A

Past the analyzer interface; allows for multi gas analysis; requires special adapter; placed near the patients airway ; subject to interference by water vapor, secretions & blood; creates 2 additional places for disconnection

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11
Q

Explain side stream systems

A

Remote from patient

Any size

More diverse

Continuously drawn from the breathing circuit via the Y piece

Passes through a filter or water trap & then enters the analyzer

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12
Q

What is the disadvantage of side stream analyzer

A

Clogging/Kinking

Slow/total response time & artifact

Rapid response time & long sampling lines may decrease accuracy of the reading

Multiple breaths will cause dampening, loss of clear peaks & troughs

Gas sampling rate that are screes the fresh gas flow rate has the potential for negative pressure to be created

Leaks can occur inside the monitor & in the tubing

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13
Q

The amount of radiation absorbed is a function of

A

Partial pressure

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14
Q

Mass spectrometer doesn’t measure partial pressure..

A

Only proportions

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15
Q

What does Dalton law say?

A

Partial pressure of all gases in the system add up to the overall pressure of the system

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16
Q

Volumes percent is a

A

Proportion

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17
Q

The greater number of molecules=

A

The more radiation is absorbed

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18
Q

Since the absorbable is determined by the number of molecules present,

A

The amount of radiation absorbed is a function of the partial pressure

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19
Q

Which gas analysis technology is most common?

A

Infrared, which is dispersive or non dispersive

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20
Q

Gas analysis techniques includes

A

Mass spectrometry

Infrared analysis

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21
Q

Spectrometry allowed the

A

Breath by breath identification &quantity indication of up to 8 gases

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22
Q

Spectrometry unit separates the components of a stream of charged particles or ions into a spectrum according to their

A

Mass & charge ratios

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23
Q

Relative abundance of ions with certain mass & charge ratios is

A

Deterred & related to the fractional composition of the original gas mixture

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24
Q

Which infrared analysis is used?

A

Non-dispersive analyzer, which uses a specific wavelength

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25
Q

What is collision broadening

A

Presence of other gases with overlapping absorption bands

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26
Q

Infrared spectrum ranges from

A

.4-40 micrometers

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27
Q

Asymmetrical true polyatomic molecules like CO2

A

Absorb infrared energy when their atoms rotate or vibrate asymmetrically

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28
Q

Symmetric molecules such as nitrogen & oxygen

A

Doesn’t absorb infrared energy

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29
Q

After the infrared radiation passes though the gas sample in the dispersive analyzer,

A

The emitted radiation is separated or dispersed into the component wavelength & arranged sequentially; a plot is obtained ( peaks)

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30
Q

In non dispersive analyzer

A

Only specific wavelengths known to interact with certain gases are passed through the gas sample & an analysis is made

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31
Q

A black box radiator doesn’t reflect any light but

A

As it’s heated, it radiates the energy as electromagnetic radiation

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32
Q

In the non dispersive analyzer, the gas is drawn through a sample cell/ corvette & the detector

A

Generates an output signal dependent upon the intensity of the infrared radiation that falls on it; narrow band filter allows radiation of only certain wavelengths

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33
Q

The intensity of the radiation is inversely related to

A

The concentration of the specific gas being measured

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34
Q

Infrared analyzers must use a

A

Specific wavelength of radiation according to the absorption peak of each gas to be measured; each analyzer uses a wavelength of 3.3 micrometers to measure inhaled anesthetics

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35
Q

The use of aerosol propellants used in inhalers would

A

Appear to the analyzer as a transient peak of halogenated agents

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36
Q

Modern analyzers have the capability of

A

Identifying & quantifying different agents

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37
Q

The IR radiation detectors are

A

Thermal plied, which is a device that converts thermal energy into electrical energy

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38
Q

Sidestream sampling analyzers continuously withdraw

A

50-250mL/minute from the breathing circuit

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39
Q

What is the disadvantage of sampling system

A

Water vapor from the breathing circuit condenses on its way to the sampling corvette & can interfere with optical transmission (water traps/filters are used to protect the optical system from condensation & body fluids)

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40
Q

In photo acoustic spectrometry,

A

A simple microphone detector is used to detect all the IR absorbing gases

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41
Q

What’s is the disadvantage of photo acoustic spectrometry

A

It’s sensitive to interference from loud noise & vibration

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42
Q

Ramen spectrometry is based on

A

The principle that when light strikes gas molecules, most of the energy is re-emitted in the same direction & at the same wavelength as the incoming beam (red shifted spectrum); not limited to gases that are polar

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43
Q

Monoatomic gases like helium & xenon

A

Do not exhibit Ramen activity

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44
Q

Which gases are measured with ramen spectroscopy

A

Nitrogen & oxygen

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45
Q

Is ramen spectroscopy still in use?

A

No due to the laser being broken up by halothane molecules & contaminating

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46
Q

pH sensitive dyes are placed

A

Between the endotracheal tube & circuit to measure CO2 absorbance (used to confirm tracheal intubation when capnography isn’t available)

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47
Q

Oxygen analyzers can be

A

Fuel cell (slow change)

Paramagnetic (quick; every breath)

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48
Q

Oxygen is polar & can

A

Change pressure with a magnet

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49
Q

With the fuel cell, flow of current depends on the uptake of oxygen & the

A

Voltage developed is proportional to the oxygen partial pressure

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50
Q

Oxygen diffuses into the sensor and a

A

Reaction takes place at hay creates current similar to a battery

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51
Q

Like a battery, fuel cell has

A

Limited life span depending on its length or f exposures to oxygen

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52
Q

The paramagnetic oxygen analyzer uses

A

A magnetic field that I attract oxygen since it has 2 electrons & unpaired orbits

53
Q

Paramagnetic analyzer compares the pressure difference between

A

Reference gas & the measured gas as they are exposed to rapidly changing magnetic fields; these pressure differences create sound waves that are sensed by microphone & converted to electrical signal

54
Q

Does the paramagnetic sensor perform its own periodic calibration?

A

Yes

55
Q

The oxygen analyzer in the anesthesia workstation prevents

A

Hypoxia gas mixtures

56
Q

Paramagnetic analyzers are utilized for

A

Inhaled & exhaled oxygen concentrations

57
Q

The slowly responding galvanic analyzer is incorporated into the machine to

A

Monitor for hypoxia gas administration

58
Q

Inspired concentration monitoring is important during

A

Preoxygenation with 100% oxygen to denitrogenate the lungs as well as monitoring oxygen concentration when this is an ignition source close to airway

59
Q

In procedures that involve the airway, it is important for oxygen concentration to be less than

A

30% to decrease the risk of fire

60
Q

The oxygen analyzer is one of the most important monitors in the breathing system as it is both

A

Qualitative & Quantitative

61
Q

What is considered the best method of confirming proper placement of the ET tube following intubation?

A

Detection of carbon dioxide ( CO2 monitoring)

62
Q

Multi gas analyzers measure

A

Inspired & endtidal concentrations of all anesthetic gases including NO; makes it possible to monitor anesthetic uptake & washout & allows high & low concentration alarms

63
Q

High fresh gas flows & vaporizer setting ensure

A

That the gas composition & the circuit changes rapidly to speed anesthesia uptake; once a he desired concentration is attained, the vaporizer setting can be decreased

64
Q

What can be used to prevent anesthetic overdosing?

A

Anesthetic agent high concentration alarm

65
Q

The low concentration alarm can prevent

A

Awareness & shows the vaporizer is either empty or there’s a leak

66
Q

What is the definition of breathing

A

Bidirectional movement of gas into the lungs followed by gas moving out of the lungs

67
Q

By monitoring inhaled & exhaled gas concentration

A

The breaths that vent the alveoli & breaths that don’t can be distinguished

68
Q

With capnography, the transition from high concentration to low concentration is

A

The start of inspiration; from low to high is start of exhalation

69
Q

Phase 2 is the

A

Beginning of expiration

70
Q

Phase 3 is the

A

Alveolar plateau and correlates with PaCO2

71
Q

If the beta angle isn’t 90 degrees,

A

There is rebreathing or mechanical obstruction

72
Q

If the aloha angle is greater than 90 degrees, the patient

A

Isn’t exhaling air as fast, resulting in air trapping, bronchospasm/VQ mismatch

73
Q

Under ideal conditions, the partial pressure of end tidal is

A

Similar to that of arterial blood, but this is dependent upon how it’s measured & patient physiology including diffusion, ventilation, & cardiac output

74
Q

For end tidal gas to mirror arterial blood,

A

The entire gas sample must contain only gas that has been exhaled from well perfumed alveoli; coming from poor perfumed alveoli= contamination

75
Q

The concentration observed over multiple breaths will

A

Likely be near to the concentration in the arterial blood

76
Q

The maximum CO2 value observed in the past

A

1-2 minutes corresponds more closely with arterial concentration; the lowest end tidal oxygen concentration observed corresponds with arterial concentration

77
Q

What are some complications of gas monitoring?

A

Hyperventilation

CO (low perfusion)

Kinked ETT

user error is more common

78
Q

What is a required standard of the ASA

A

Monitoring of FiO2 & pulse oximetry

79
Q

What are the defining characteristics of spontaneous ventilation

A

Depth & frequency

Frequency most fundamental

80
Q

Common cause of tachypnea

A

Periop pain

81
Q

What are other ways to monitor RR

A

Thoracic impedance & EKG monitoring (most common)

Acoustic techniques (listening to the face, neck or chest)—-this method suffers from ambient noise interference

82
Q

The electrical resistance in the thorax changes with

A

Inflation & deflation of the lungs

83
Q

Impedance changed with

A

The change in the shape of the thorax

84
Q

EKG changed in both

A

Amplitude & signal & there are changes in the QRS complex occurring during ventilation

85
Q

Amplitude changes are due to

A

A change in the overall electrical resistance of the chest due to the increased proportion of air in the chest cavity

86
Q

Inflation of the lungs also produces a change in

A

Access to the heart

87
Q

70% of disconnections occur at the

A

Y piece

88
Q

Volume control will deliver a set tidal volume & pressure that will

A

Increase until the tidal volume is reached

89
Q

Pressure control delivers a set

A

Pressure & tidal volume will depend on airway resistance & lung & chest wall compliance

90
Q

Pressure control can improve both

A

Ventilation & oxygenation

91
Q

Subatmospheric pressure alarms alert clinicians to

A

Negative circuit pressure which could rapidly cause pulmonary edema, atelectasis & hypoxia; this can occur from suction of the scavenging system, patient effort against blocked circuit, or circuit with an inadequate gas flow

Place meant of gastric tube applied to suction can cause negative oressure

92
Q

When is the continuous pressure alarm triggered

A

When circuit exceeds 10cm of water for more than 15 seconds, which can be caused by ventilators pressure relief valve, system occlusion or a tight APL valve & spontaneous breathing; forget to turn on ventilator

93
Q

How to measure minute volume

A

Tidal volume x RR

94
Q

The simplest device for the measurement of gas volume is based on a

A

Rotating vein or propeller calibrated against the specific density of a gas; the rotation of the attached shaft correlates with the volume of gas that is passed by

95
Q

Force is transmitted to the veins. Y the impact of the gas molecules &

A

This is converted to a rotational momentum & spins the pinwheel; the count is converted to volume

96
Q

What are the variables of volume measurement

A

Gas compositions

Humidity

Altitude

Temperature

97
Q

Low flows will cause the turbine to

A

Accelerate more slowly (volume & accuracy due to inertia effects); still safe

98
Q

Turbulent flow is

A

Characterized by the formation of eddies or vortices in hay cause increased drag

99
Q

Resistance is low in laminar or turbulent flow

A

Laminar

100
Q

Poiseuille law only applies to

A

Laminar flow

101
Q

Rotameters can measure

A

Gas vapor or liquid flow; floating bobbin rotates to prevent friction

102
Q

Rotameter must be

A

Vertical to avoid friction or collision with the wall

103
Q

You can instantly detect the velocity & direction of tidal flows with the

A

Pitot tube flow meter; it measures the pressure difference of gas impacting a port & compares that pressure with a static monitor

104
Q

Pressure difference are proportional to

A

The flow rate; direction of flow can be determined

105
Q

Describe Fleish Pneumotachometer

A

Measures the loss of energy of gas as it passes through a resistive element

The energy lost is measured as a pressure different form the inlet to the outlet of the element

Element assures the follow is laminar

Energy loss is due to viscosity & flow is directly proportional am to the pressure deference

106
Q

Fleish Pneumotachometer is used

A

In pulmonary physiology & pulmonary function studies

107
Q

Turbulent flow fixed orifice flow meters use

A

The measured pressure differential between 2 ports separated by an orifice

Calculates the pressure difference between the upstream & downstream

Laminar-Upstream

Turbulent-Downstream

108
Q

A variable orifice flow meter sensors monitors both

A

Inspiratory & expiratory flows & volumes

Decreased sensitivity at low flows is compensated by the flapper valve between the 2 pressure sensors

Increases in size with larger flows

109
Q

Gas flow rates can be measured with a heated wire by

A

Measuring the cooling of the wire from heat transfer to the gas flowing by

Heat transfers a function of the gas velocity

Limited to only laminar flow

Able to measure a wide variety of flow rates

110
Q

Sensitive flow meter used for monitoring variable flows used

A

Ultrasound reflection from moving columns of gas or liquid

Signal travel faster when moving with the flow

Difference between the 2 transit times are used to calculate the gas flow rates

Applicable to liquids, gases & multiphase mixtures

111
Q

Spirometer display include

A

Time, volume, flow & pressure

Time is always on horizontal axis

FVC ratio used to determine airflow limitation’s & distinguished between obstructive & restrictive lung disease

112
Q

Inspiration on volume time curves are depicted as

A

Up slopes
Exhalations
Down slopes

Curves can identify auto PEEP, expiratory limb leaks, forced exhalation & flow transducer miscalibrations

113
Q

Expiratory curve will not return to base line if there’s a

A

Limb leak

114
Q

Square flows represent

A

Constant inspiratory flows that create shorted inspiratory times & longer exhalation times

115
Q

Flow volume loops represent

A

Flow rate versus inspiration & expiratory volumes

116
Q

Spontaneous loop will show both

A

Negative & positive pressures, but negative pressure may be absent if PEEP is applied

117
Q

Respiratory cycle started with

A

Inhalation, moving clockwise

118
Q

With ventilation, inspiration requires

A

An increase in airway pressure & exhalation requires a decrease

119
Q

Volume control mode & decreased compliance =

A

Barotrauma

120
Q

Pressure control & decreased compliance =

A

Decreased tidal volume

121
Q

The concentrator only delivers

A

95% oxygen, not 100%

122
Q

Compliance is defined as

A

Changing volume per unit change in pressure & its not fixed

123
Q

Smaller lung volumes & decreased compliance means a

A

Rightward & downward shift of the loop

124
Q

What will be seen before tachycardia, cyanosis & tachypnea

A

Capnography rise

125
Q

What’s doesn’t detect breathing system disconnects as rapidly as pressure alarms, but able to detect esophageal intubation, CO change, inadequate pulmonary circulation & embolism

A

Capnography

126
Q

A rapid rise in this is an early indicator of limited hyperthermia

A

Capnography

127
Q

Continuous monitoring of end tidal CO2 is

A

A non invasive method for estimating arterial pressure of carbon dioxide

128
Q

Capnography can identify

A

Hyperventilation & apnea before the onset of hypoxia