Chapter 5 Resp. Monitoring

Front 1

Noninvasively estimates the hemoglobin oxgen saturation of arterial blood

Back 1

pulse oximetry

Front 2

most pulse oximeters use two wavelengths, ___ (660) and ___ (940nm) at which HbO2 and deoxyhemoglobin (Hb) have different absorption characteristics.

Back 2

red and infrared

Front 3

red and infrared light-emitting diodes ___ in the oximeter probe serve as light source.

Back 3

LED

Front 4

Bc HbO2 and Hb differ in light avsorption at each wavelenght the amount of red and infrared light transmitted is related to ___ saturation

Back 4

O2

Front 5

a photodiode positioned on the opposite side of the probe serves as the ___

Back 5

photodetector

Front 6

To identify the oxgyen saturation of the arterial blood only, the divice relies on the pulsatile nature of___

Back 6

arterial flow

Front 7

During ___ a new volume of blood enters the arteriolar bed, and light absorp. increase

Back 7

systole

Front 8

During ___ absorption decreases to a minimal level

Back 8

diastole

Front 9

Is related to the ratio of minimum and maximum absorption at each wavelength

Back 9

oxygen saturation (SpO2)

Front 10

Devices vary by manufacturer in the type of

Back 10

LED, photodiode, and microprocessor

Front 11

most pulse oximeter probes use ___ ____, sending light through the arterial bed to a photo detector on the opposite side

Back 11

transmittance spectrophotometry

Front 12

With____ pulse oximeter sensors place the light source and detector on the same side of the arterial bed.

Back 12

reflectance spectrophotometry

Front 13

Pulse oximeter measurements have an accuracy of +4% at SpO2 greater than

Back 13

80%

Front 14

To appreciate the implications of the accuracy of pulse oximetry, one must consider the ___ ___ ___

Back 14

HbO2 equlibration curve

Front 15

If the pulse oximeter displays a SpO2 of 95% the true saturation could be as low as ___% or as high as ___%

Back 15

91/99

Front 16

If the true saturation is 99% the ___ might be very high.

Back 16

PaO2

Front 17

A shift in the HbO2 equlib. curve can change the SpO2 although no change in __ has occurred

Back 17

PaO2

Front 18

A shift in the HbO2 equlib. curve can change the SpO2 although no change in __ has occurred

Back 18

PaO2

Front 19

The Pulse oxymetry provides no direct information about the Paco2 and may not accurately reflect the Pao2 bc of changes in the shape and position of the ___

Back 19

Hbo2 dissociation curve

Front 20

Pulse oximetry is accurate when

Back 20

all hemoglobin is either oxyhemoglobin or deoxyhemoglobe, when there are no other absorbers between the LEDs and the detector other than those present during the empirical calibration, & when all the blood that pulsates is arterial blood

Front 21

With low perusion there is an ___ in the ratio of venous blood to arterial blood at the measuring site.

Back 21

increase

Front 22

Low perfusion is associated with lower pulse amplitude, so the __ ___ ____ has a greater effect when combined with a low signal

Back 22

noise of motion

Front 23

Strategies to address issues trlated to motion and low perfusion include

Back 23

averging the saturation data over alonger periond of time and suspending the report of data until clean data are available.

Front 24

The pulse oximetry plethysmographic (POP) waveform may display the effect of ____ ___, and therefore the severity of air trapping in obstructive airway disease

Back 24

pulsus paradoxus

Front 25

In pts. with obstuctive lung disease and elevated pulsus paradoxus, there is an altered pulse oximetry baseline tracing manifested as the respiratory waveform _____

Back 25

variation

Front 26

Pulsus paradoxus is significantly correlated with the degree of respiratory waveform variation of the pulse oximetry tracing and the amount of auto- _____

Back 26

PEEP (positive end -expiratory pressure)

Front 27

respiratory variations in POP waveform amplitude have also been shown to be useful in prediction of ___ responsivensess

Back 27

fluid

Front 28

POP waveform amplitude is mearsured on a beat to beat basis as the vertical distance between

Back 28

peak and preceding valley trough in the wavefom

Front 29

A POP greater than 15% is prdictive of fluid responsiveness in mechanically ventilated patients with

Back 29

circulatory failure

Front 30

- law defining the relationship between the concentration of a substance and the amount of light (I) transmitted through it

Back 30

Beer- Lambert law

Front 31

assessment of gas at the proximal airway that plots CO2 on the vertical axis and time or volume on the horizontal axis

Back 31

Capnogram

Front 32

- noninvasive technique that measures CO2 levels in inspired and expired gas and displays a capnogram

Back 32

Capnography

Front 33

numeric display of CO2 measurement taken from the proximal airway

Back 33

Capnometry

Front 34

- a medical imging technique in which an image of a part of the body is inferred from surface electrical measurement. Conducting electrodes are attached to the skin, and small alternating currents are applied to the electrodes. The resulting electrical potententials are measured, and the process may be repeated for numerous different configurations of applied current.

Back 34

Electrical impedance tomography (EIT)

Front 35

- PCO2 at end exhalation (PETCO)

Back 35

End-tidal PCO2

Front 36

- rib cage or abdominal displacements stretch an elastic belt, which changes light transmission through the fibers result

Back 36

Fiberoptic plethysomography

Front 37

- method for measuring respiratory rate and excursion using two electrodes placed on the chest wall and then passing a high-frequency and low-ampere AC current between the electrodes on the chest surface

Back 37

Impedance pneumography-

Front 38

instrument capable of measuring all respiratory gases, including respiratory and anesthetic gases, breath by breath

Back 38

Mass spectrometer-

Front 39

a condition that can occur during the application of pulse oximetry in which the sensor is not correctly positioned. This effect causes incorrect readings when the sensor is not symmetrically placed, causing one wavelength to be overused in the calculations of satruration

Back 39

Penumbra effect

Front 40

a value derived from the photoelectric plethysmographic signal of a pulse oximeter and calculated as the ratio of the pulsatile component (arterial compartment) and the nonpulsatile component (other tissues; venous blood, bone, connective tissue) of the light reaching the device’s detector

Back 40

Perfusion index (PI)-

Front 41

- type of plethysmography apparatus that replaces wire coils from the elastic belts with a piezoelectric buckle, which encloses a sensor to generate a voltage in response to stretch passed through the end of the belts.

Back 41

Piezoelectric plethysmography

Front 42

- abnormal decrease in systolic pressure and pulse wave amplitude during inspiration

Back 42

Pulsus paradoxus

Front 43

method used to measure CO2

Back 43

Raman spectroscopy

Front 44

Method for indirectly measuring tidal volume; sensors use a circuit of coiled wire woven into an elastic band and excited by an AC current. Inductance results from alternation electrical currents creating magnetic fields around themselves and those changing magnetic fields altering other electrical currents that they encounter

Back 44

Respiratory inductance plethysmography (RIP)-

Front 45

- method that identifies substances by their absorption (also called extinction) of specific wavelengths in the electromagnetic spectrum

Back 45

Spectrophotometry

Front 46

thermometer that can measure extremely small changes in temperature

Back 46

Thermistor-

Front 47

- apparatus that detects bidirectional airflow at the nose and mouth by sensing the temperature difference between inspired room air and exhaled air that has been warmed to body temperature; an active sensor used to measure temperature

Back 47

Thermocouple

Front 48

monitoring- a means of respiratory monitoring of blood gases through electrodes applied to the skin

Back 48

Transcutaneous