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Flashcards in Measurement and monitoring Deck (195)
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1

In pulse oximetry
the SpO2 is determined by the absorbance of light wavelengths 660nm and 940nm

True

2

In pulse oximetry
Methaemaglobinaemia causes the SpO2 to approach 85%

True

3

In pulse oximetry
Fetal haemaglobin gives an inaccurately high reading of saturation

False

4

In pulse oximetry
oxyhaemoglobin absorbs better at the longer wavelength

True

5

In pulse oximetry
The pulse oximeter is less accurate at low rather than high saturations

True

6

In pulse oximetry
The arterial a.c (pulsatile) component of the signal is approximately 20% of the total absorption

False

7

In pulse oximetry
functional saturation is defined as the ratio of oxyhaemoglobin to oxyhaemoglobin plus reduced haemoglobin

True

8

In pulse oximetry
beers law relates the intensity of transmitted light to the path length

False

9

In pulse oximetry
infrared light is only absorbed by small molecules with symmetric bonds

False

10

In pulse oximetry
motion artifacts produces a high a.c to d.c signal ratio

True

11

Causes of inaccuracies on pulse oximetry include
methaemoglobinaemia

True

12

Causes of inaccuracies on pulse oximetry include
fetal haemoglobin

False

13

Causes of inaccuracies on pulse oximetry include
hypothermia

True

14

Causes of inaccuracies on pulse oximetry include
blue nail polish

True

15

Causes of inaccuracies on pulse oximetry include
extraneous light

True

16

Concerning the measurement of oxygen
A clark electrode requires a polarising voltage

True

17

Concerning the measurement of oxygen
fuel cells can be affected by the presence of nitrous oxide

True

18

Concerning the measurement of oxygen
paramagnetic analyser has a slower response time than a clark electrode

False

19

Concerning the measurement of oxygen
A polarographic technique is used in normal blood gas analysers

True

20

Concerning the measurement of oxygen
oxygen saturation is directly measured using co-oximeter

False

21

The following are directly measured in a standard blood gas analyser
pH

False

22

The following are directly measured in a standard blood gas analyser
bicarbonate

False

23

The following are directly measured in a standard blood gas analyser
oxygen tension

True

24

The following are directly measured in a standard blood gas analyser
partial pressure of CO2

False

25

The following are directly measured in a standard blood gas analyser
oxygen saturation

False

26

Arterial blood gas samples
storage at room temp causes a rise in pH

False

27

Arterial blood gas samples
a hypothermic patient will have inaccurately high pO2 if temperature-correction is not employed

True

28

Arterial blood gas samples
Air bubbles in the sample may lead to a fall in the pO2

True

29

Arterial blood gas samples
excessive heparin will cause an inaccurately high pH

False

30

Arterial blood gas samples
storage at room temp causes a fall in pO2

True

31

The oxygen electrode in a blood gas analyser
incorporates on a lead anode

False

32

The oxygen electrode in a blood gas analyser
the cathode is usually platinum

True

33

The oxygen electrode in a blood gas analyser
potassium hydroxide is the usual electrolyte in the electrode

False

34

The oxygen electrode in a blood gas analyser
current flow depends on oxygen tension at the cathode

True

35

The oxygen electrode in a blood gas analyser
is of the fuel cell type

False

36

The fuel cell
contains a lead anode

true

37

The fuel cell
has a faster response time than a polargraphic electrode

False

38

The fuel cell
is not affected by temperature

False

39

The fuel cell
nitrous oxide in the gas mixture reacts with the anode to produce nitrogen

True

40

The fuel cell
is used to measure oxygen tensionin a blood gas analyser

False

41

Concerning the clark PO2 electrode
is composed of a platinum cathode and a gold anode

False

42

Concerning the clark PO2 electrode
an oxygen consuming electrochemical reaction takes place at the anode

False

43

Concerning the clark PO2 electrode
it can be used to measure oxygen partial pressure in gases and liquids

True

44

Concerning the clark PO2 electrode
it requires a voltage of 0.6V to be applied between its electrode

True

45

Concerning the clark PO2 electrode
it is sensitive to changes in temperature

True

46

The Severinghaus CO2 electrode
incorporates KCL and NaHCO3 in the electrolyte solution

True

47

The Severinghaus CO2 electrode
directly measures the Pa CO2

False

48

The Severinghaus CO2 electrode
incorporates hydrogen ion sensitive glass

True

49

The Severinghaus CO2 electrode
incorporates a platinum wire cathode

False

50

The Severinghaus CO2 electrode
is affected by temperature

True

51

Recognised methods of measuring anaesthetic vapour concentration include
Raman scattering

True

52

Recognised methods of measuring anaesthetic vapour concentration include
Paramagnetism

False

53

Recognised methods of measuring anaesthetic vapour concentration include
ultraviolet absorption

True

54

Recognised methods of measuring anaesthetic vapour concentration include
mass spectrometry

True

55

Recognised methods of measuring anaesthetic vapour concentration include
photoacoustic spectrophotometry

True

56

The following can be used to measure carbon dioxide in expired gases (capnography)
clark polargraphic electrode

False

57

The following can be used to measure carbon dioxide in expired gases (capnography)
paramagnetic analyser

False

58

The following can be used to measure carbon dioxide in expired gases (capnography)
infrared absorption spectrometry

True

59

The following can be used to measure carbon dioxide in expired gases (capnography)
mass spectrometry

True

60

The following can be used to measure carbon dioxide in expired gases (capnography)
Ramen analyser

True

61

The following have infrared absorption spectra which overlap with that of carbon dioxide
water vapour

True

62

The following have infrared absorption spectra which overlap with that of carbon dioxide
sevoflurane

True

63

The following have infrared absorption spectra which overlap with that of carbon dioxide
nitrous oxide

True

64

The following have infrared absorption spectra which overlap with that of carbon dioxide
nitrogen

False

65

The following have infrared absorption spectra which overlap with that of carbon dioxide
helium

False

66

Concerning the measurement of expired CO2 using the infrared absorption technique
the wavelength of infrared light used is 4.3 micrometers

True

67

Concerning the measurement of expired CO2 using the infrared absorption technique
the absorption of infrared light by CO2 is based on the beer-lambert law

True

68

Concerning the measurement of expired CO2 using the infrared absorption technique
the windows on the sample chamber are made of lead crystal glass

False

69

Concerning the measurement of expired CO2 using the infrared absorption technique
nitrous oxide interferes with infrared absorption by CO2

True

70

Concerning the measurement of expired CO2 using the infrared absorption technique
O2 interferes with infrared absorption by CO2

True

71

Concerning spectrophotometric absorption spectra or reduced and oxygenated haemoglobin
at the isobestic point the absorption coefficient is the same

True

72

Concerning spectrophotometric absorption spectra or reduced and oxygenated haemoglobin
the isobestic point occurs at a wavelength around 650nm

False

73

Concerning spectrophotometric absorption spectra or reduced and oxygenated haemoglobin
the amount of oxygenated haemoglobin is directly proportional to the shift in the isobestic point

False

74

Concerning spectrophotometric absorption spectra or reduced and oxygenated haemoglobin
the maximum difference in the absorption of the two forms of haemoglobin occurs at a wavelength around 940nm

False

75

Concerning spectrophotometric absorption spectra or reduced and oxygenated haemoglobin
The pulse oximeter usess the difference between the absorption spectra of the two forms of Hb to quantify their relative concentrations

True

76

Refractometers:
are capable of measuring vapour concentration in gas mixture

True

77

Refractometers:
require calibration

True

78

Refractometers:
directly measure the vapour concentration

False

79

Refractometers:
are not influenced by water vapour

False

80

Refractometers:
are used to calibrate vapourisers

True

81

Blood-gas analysis:
The base excess is the amount of strong acid required to return the pH of 1 litre of blood to 7.40 at a PCO2 of 5.3 kPa and 37C

True

82

Blood-gas analysis:
too much heparinised saline tends to cause a falsely low reading of the PCO2

True

83

Blood-gas analysis:
Too much heparing tends to cause a falsely lo reading of potassium concentration

False

84

Blood-gas analysis:
A clark electrode requires a battery

True

85

Blood-gas analysis:
prolonged storage at 4C may lead to a falsely low vlue for PO2

True

86

The following statements are correct
visible light has a wavelength between 400 and 700 nm

True

87

The following statements are correct
CO2 has a peak absorption at 4.3 micrometers

True

88

The following statements are correct
3.3 micrometers is the commen absorption peak for the volatile anaesthetic agents

True

89

The following statements are correct
methane interferes with gas analysis in the 9-11 micrometer band

False

90

The following statements are correct
Collision broadening alters the wavelength at which infrared absorption by CO2 takes place

True

91

Concerning mass spectrometry
The analysing hamber is operated at atmospheric pressure

False

92

Concerning mass spectrometry
The ions are accelerated by an anode plate

False

93

Concerning mass spectrometry
In a quadrupole mass spectrometer there are two large electromagnets

False

94

Concerning mass spectrometry
The sample from a mass spectrometer can be returned to a circle system to allow low flow anaesthesia

False

95

Concerning mass spectrometry
mass spectrometry is less accurate than infrared absorption

False

96

The following statements are correct
fuel cells are suitable for breath to breath analysis of oxygen concentration

False

97

The following statements are correct
Unpaired elctrons are responsible for oxygens paramagnetic property

True

98

The following statements are correct
damping coefficient is inversely proportional to the amplitude ratio in invasive arterial pressure measurement

True

99

The following statements are correct
The natural frequency of a mass-string dynamic oscillator is directly proportional to its mass

False

100

The following statements are correct
fourier tranformation is a mathematical operations that deconstructs a complex signal into its constituent frequencies

True

101

The following physical properties may be used in the measurement of pressure:
Change or electrical resistance in a wire

True

102

The following physical properties may be used in the measurement of pressure:
Variable inductance

True

103

The following physical properties may be used in the measurement of pressure:
Piezoelectric effect

False

104

The following physical properties may be used in the measurement of pressure:
Change in flow through a narrow tube

False

105

The following physical properties may be used in the measurement of pressure:
Torricellian vacuum

True

106

Non-invasive measurement of blood pressure:
Tends to give lower systolic pressure than direct means

True

107

Non-invasive measurement of blood pressure:
the diastolic pressure is recorded as the pressure at which the first muffling of the sound occurs

False

108

Non-invasive measurement of blood pressure:
The mean arterial pressure is the point of maximum oscillation in the cuff pressure

False

109

Non-invasive measurement of blood pressure:
requires a cuff that is wider than the diameter of the arm

True

110

Non-invasive measurement of blood pressure:
Tends to give a lower diastolic pressure than direct means

False

111

Transducers commonly used in physiological monitoring include:
Strain gauge

True

112

Transducers commonly used in physiological monitoring include:
pH meter

True

113

Transducers commonly used in physiological monitoring include:
Ear Oximeter

True

114

Transducers commonly used in physiological monitoring include:
ECG electrode

False

115

Transducers commonly used in physiological monitoring include:
Galvanic fuel cell

True

116

Considering direct intra-arterial blood pressure measurement:
in an underdamped transducer system (D<0.5) significant overshoot and subsequent oscillation occurs

True

117

Considering direct intra-arterial blood pressure measurement:
in an optimally damped system (D=0.64) overshoot is limited to 6-7% of the initial pressure change and no oscillation will occur

True

118

Considering direct intra-arterial blood pressure measurement:
In a critically damped system (D=1.0) the change in mean pressure will be measured accurately with no overshoot

True

119

Considering direct intra-arterial blood pressure measurement:
In an overdamped system (>1.0) the response is progressively slower

True

120

Considering direct intra-arterial blood pressure measurement:
A fast fluch test can be used to assess the level of damping

True

121

Distortion of the trace seen in direct arterial monitoring is increased by:
Bubbles

True

122

Considering direct intra-arterial blood pressure measurement:
Connections in the tubing

True

123

Considering direct intra-arterial blood pressure measurement:
Shortening the tubing

False

124

Considering direct intra-arterial blood pressure measurement:
increasing the diameter of the tubing

False

125

Considering direct intra-arterial blood pressure measurement:
clots in the cannula

True

126

Measuring cardiac output by the thermodilution method:
Injecting less than the required volume of injectate leads to an over-estimation of the cardiac output

True

127

Measuring cardiac output by the thermodilution method:
injection should be performed over about 10 sec

False

128

Measuring cardiac output by the thermodilution method:
Looping of the catheter in the right ventricle may cause inaccuracies in the measurement

True

129

Measuring cardiac output by the thermodilution method:
The cardiac output is assessed by measuring the area under the temperature change curve

True

130

Measuring cardiac output by the thermodilution method:
Cardiac output measurements will be unchanged by wedging of the pulmonary artery catheter

False

131

The following may be employed in the measurement of cardiac output:
Lithium Dilution

True

132

The following may be employed in the measurement of cardiac output:
thermal conductivity

False

133

The following may be employed in the measurement of cardiac output:
Indocyanine green indicator dilution

True

134

The following may be employed in the measurement of cardiac output:
Impedance cardiography

True

135

The following may be employed in the measurement of cardiac output:
Aortic Doppler Ultrasound

True

136

Using Fick principle to measure cardiac output, with oxygen as the indicator gas, it it essential to know the:
oxygen uptake

True

137

Using Fick principle to measure cardiac output, with oxygen as the indicator gas, it it essential to know the:
arterial oxygen content

True

138

Using Fick principle to measure cardiac output, with oxygen as the indicator gas, it it essential to know the:
respiratory quotient

True

139

Using Fick principle to measure cardiac output, with oxygen as the indicator gas, it it essential to know the:
mixed venous oxygen content

True

140

Using Fick principle to measure cardiac output, with oxygen as the indicator gas, it it essential to know the:
arterial carbon dioxide content

False

141

Bispectral index:
Is measured in Hertz

False

142

Bispectral index:
is used as a measure of the depth of anaesthesia

True

143

Bispectral index:
is not affected by natural sleep

False

144

Bispectral index:
preoperative opioids decrease the value

False

145

Bispectral index:
is a reliable monitor to predict recall under anaesthesia

False

146

With reference to the principles of oesophageal doppler cardiac output monitoring:
The volume of blood flowing in the descending aorta is measured

False

147

With reference to the principles of oesophageal doppler cardiac output monitoring:
The angle of insonation between the ultrasound waves and the blood stream must be known

True

148

With reference to the principles of oesophageal doppler cardiac output monitoring:
The cross sectional area of the aorta must be known

True

149

With reference to the principles of oesophageal doppler cardiac output monitoring:
The probe should be positioned so the tip faces anteriorly

False

150

With reference to the principles of oesophageal doppler cardiac output monitoring:
The probe measures total cardiac output

False

151

Regarding depth of anaesthesia monitoring:
Auditory evoked potentials are a composite waveform

True

152

Regarding depth of anaesthesia monitoring:
Entropy is calculated from the amount of disorder in the power spectrum of the EEG

True

153

Regarding depth of anaesthesia monitoring:
Bispectral index is agent specific

False

154

Regarding depth of anaesthesia monitoring:
Entropy is reported using a dimensionless scale

True

155

Regarding depth of anaesthesia monitoring:
Auditory evoked potentials exhibit minimal hysteresis

True

156

The following are true of nerve stimulators:
The applied electrical potential can be as high as 150V

True

157

The following are true of nerve stimulators:
The apparatus uses a square wave electrical signal

True

158

The following are true of nerve stimulators:
The pulse current should be between 0.5 and 5.0mA when the skin electrodes are used

False

159

The following are true of nerve stimulators:
At a constant voltage, an increase in resistance is associated with an increase in current flow

False

160

The following are true of nerve stimulators:
Stimulation at a constant current is preferable to stimulation at a constant volatage

True

161

When using a train of four to monitor a non-depolarising block:
The stimulator should deliver four supramaximal stimuli at 4Hz

False

162

When using a train of four to monitor a non-depolarising block:
The fourth twitch (T4) will be smaller than the first twitch

True

163

When using a train of four to monitor a non-depolarising block:
Post-tetanic facilitiation is due to accumulation of acetylcholine in the synaptic cleft

True

164

When using a train of four to monitor a non-depolarising block:
The response to muscle relaxants of the facial muscles is similar to that of the diaphragm

True

165

When using a train of four to monitor a non-depolarising block:
Presence of all four twitches indicates a patient who is adequately reversed for extubation

False

166

The following statements are true of double burst stimulation neuromuscular monitoring:
It consists of two burst of tetanus at 100Hz

False

167

The following statements are true of double burst stimulation neuromuscular monitoring:
each impulse is separated by 20sec

False

168

The following statements are true of double burst stimulation neuromuscular monitoring:
The 2 bursts are separated by 750msec

True

169

The following statements are true of double burst stimulation neuromuscular monitoring:
The DBS ration has similar properties to the TOF ratio

True

170

The following statements are true of double burst stimulation neuromuscular monitoring:
DBS is accurate at detecting deep neuromuscular block

False

171

Concerning temperature measurement:
A mercury thermometer is suitable for measuring temperatues from -30C to at least 200C

True

172

Concerning temperature measurement:
A resistance thermometer is normally used in a wheatstone bridge configuration

True

173

Concerning temperature measurement:
Thermistors are metal oxide superconductors

False

174

Concerning temperature measurement:
Thermistors are resistant to heat sterilisation

False

175

Concerning temperature measurement:
A thermocouple relies on the seebeck effect

True

176

The fleisch Pneumotachograph:
is a constant pressure flowmeter

False

177

The fleisch Pneumotachograph:
is not useful for breath-to-breath measurements

False

178

The fleisch Pneumotachograph:
is designed to measure laminar flow

True

179

The fleisch Pneumotachograph:
uses a pressure transducer to measure flow

True

180

The fleisch Pneumotachograph:
becomes inaccurate because condensation is common

False

181

Concerning rotameters:
It consists of a vertical tube with even diameter

False

182

Concerning rotameters:
The pressure drop across the bobbin increases with increasing flow

False

183

Concerning rotameters:
At low flows, the viscosity of the gas becomes important

True

184

Concerning rotameters:
At high flows the density of the gas becomes important

True

185

Concerning rotameters:
In a hyperbaric chamber, a flowmeter will deliver less gas than the setting indicate

True

186

Concerning rotameters:
Are a form of variable orifice flowmeter

True

187

Concerning rotameters:
Are susceptible to static electricty

True

188

Concerning rotameters:
Should be accurate to within 0.2%

False

189

Concerning rotameters:
Consists of a bobbin in a parallel-sided tube

False

190

Concerning rotameters:
The bobbin has vanes to help it to spin freely

True

191

Regarding humidity:
Absolute humidity = volume of water vapour in unit volume of air at specified pressure & temp

False

192

Regarding humidity:
Relative humidty = partial pressure of water vapour divided by the SVP of water at specified temp

True

193

Regarding humidity:
Absolute humidity can be measured by a Regnault's hygrometer

False

194

Regarding humidity:
The Regnault's hygrometer relies on evaporation

True

195

Regarding humidity:
Absolute humidity is independent of temperature

True