Term
|
Definition
Measure of hydrogen ion activity in a liquid.
Very similar to hydrogen ion concentration [H+].
PH = -log10[H+]
As PH decreases, [H+] increases |
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Term
|
Definition
PH = 7.4
[H+] = 40 nmol liter-1 at 37 degrees C
On a graph, relationship is nearly linear
7.4 = 40
7.3 = 50
7.2 = 60
[H+] 1x10-3 mol/L = PH 3
[H+] 1x10-8 mol/L = PH 8 |
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Term
|
Definition
Ion selective electrode
dependent on ion sens glass
temp must be 37C
Must account for different temps
needs calibration
can be used fro urine and CSF also |
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Term
|
Definition
Severinghaus Electrode
Measurement of ventilation not oxygenation
NL 5.3kpa or 40mmHg
based on [H+] measurements
CO2 + H2O = H2C03- = H+ + HCO3
Indirect measurement of CO2
Response time is 2-3 min
Temperature control at 37C
Compensate for humidification when calibrating |
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Term
| What does an Infrared Analyzer measure? |
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Definition
Inspired and expired gasses
Gases with two or more molecules (not O2 or N2,but CO2 or N2O2)
Capnography - con't CO2 monitoring, near real time 1 sec delay.
Also volatile anesthetics: isoflorine, desflorine, sevoflorine. |
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Term
| What are the principles of Infrared Analyzer? |
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Definition
Gas mixtures absorb infrared energy and by measuring the fraction absorbed by the mixture, the partial pressure of a particular gas can be determined.
Measurement of concentration is proportional to absorption.
Wavelength dependent.
Must compensate for other gases (collision broadening Effect) |
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Term
| What is the collision broadening effect? |
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Definition
As molecules approach and recede from each other , their energies alter slightly and this affects the energy at which they absorb infrared radiation.
Since most anesthesia mixtures contain N2O, compensation must be done (either manual or automatic) |
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Term
| What are the two types of capnographs |
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Definition
Mainstream
Sidestream- not used much too much delay |
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Term
|
Definition
Study of CO2 - real time
Important for diagnostic and monitoring purposes in anesthesia
Standard of Care |
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Term
| What waveforms are important in capnography? |
|
Definition
Rebreathing
Breathing - Curare Notches indicate reversal
Ventilation - hypo/hyper CO2 -- ventilation
Valve Problems
Emboli |
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Term
| What are the two components of capnography response time? |
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Definition
| Rise Time and Transit time |
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Term
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Definition
| The time for the sample to be transferred to the analyzer. This is typically 1 second |
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Term
|
Definition
Time for analyzer to respond to the signal. Time measured for the indication on the analyzer to change from 10% to 90% of final value.
Under 400ms good.
Dependent upon size of sample chamber and gas flow.
Too low a flow with give a long rise time. |
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Term
| How fast does the gas sample drawn in to a gas analyzer (capnograph)? |
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Definition
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Term
| What is another type of liquid or gas analysis that separates a mixture into it's components to measure concentrations. What is a disadvantage of this type? |
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Definition
Gas/Liquid Chromatography.
Cannot do continuous analysis |
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Term
| What are some clinical uses for gas chromatography? |
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Definition
Measure Volatile anesthetics (both concentrations and scavenged gases)
Measures barbs, benzos, steroids, and catecholamines |
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Term
| What is another way to measure gases where the sample is bombarded by a beam of electrodes and the molecules of gas become charged and then deflected (dependent on mass) by a magnetic field. The molecules are then fragmented and the fragment pattern identifies the materials in the sample |
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Definition
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Term
| What are the Pro's and Con's of Mass Spectrometry? |
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Definition
Pro: may be used in real time analysis of breathing gases in anesthesia.
Cons: Heavy and not portable
Not easy to calibrate |
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Term
| What is the Raman Effect? |
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Definition
An effect of electromagnetic radiation in which there is partial transfer of energy between the radiation and the molecule.
Energy transfer affects the energy of vibration associated with bonds between atoms in the molecule, so absorption of radiation at a particular wavelength is associated with a specific type of bond between atoms in the molecule. |
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Term
| What is so great about the anesthetic gas analyzer based on the Raman Effect? |
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Definition
Highly Accurate
Can analyze 8 different gases at the same time
Uses a helium-neon laser |
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Term
| What are the three systems that deliver gases and anesthetic vapors? |
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Definition
Open
Non Rebreathing
Closed |
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Term
| Pro's and Con's with Open System |
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Definition
Pro's: Simplest, no valves, patient remains breathing, no resistance.
Con's: Little control over concentration delivered, no positive pressure ventilation, dilution with air may occur, peak flow my reach 50L/min |
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Term
| What are the 4 categories of breathing systems used for accurate control of gas concentration? |
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Definition
Non Rebreathing Valve
T-Piece
Magill
Closed Systems |
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Term
|
Definition
| taking a breath of clean air, and after you exhale, you re-inhale exhaled gases |
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Term
| What is the Ambu bag an example of? And what is it used for? |
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Definition
Non-Rebreathing system
Has one way insp. and exp. valves
Gases do no mix.
Used for emergencies, and controlled ventilation
Can't use on spontaneously breathing patients. |
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Term
| What are some things to know about the T-Piece systems? |
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Definition
No Valves, ok for spont breathing patients
Corregated tube prevents entrainment of air from surroundings
allows deadspace gases to be exhaled
allows gases from alveolis to get further downstream to prevent rebreathing
a typical system requires 2-2.5 time the tidal volume of fresh gas flow to avoid rebreathing
The capacity of the tube has to equal the pts tidal volume |
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Term
| What is the benefit of the Expiratory pause? |
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Definition
| Can decrease the amount of fresh gas flow needed |
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Term
| Which T-Piece is used in pediatrics and why? |
|
Definition
Mapleson D
Close to the patient's airway to avoid deadspace
Has exp valve to avoid problems during spont ventilation
decreased resistance |
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Term
| What is the Coaxial T piece? |
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Definition
The Bain circuit which is known as the modification of the Mapleson D T piece. Used for controlled ventilation of the pediatric patient
Fresh Gas Flow line is in the limb of the T
FGF should still be 2.5 times the TV
Don't let it kink
Warms inspired gases |
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Term
| What is the Magill or Mapleson A system? |
|
Definition
Used for spontaneously breathing patients.
Has exp valve near the patient's airway to conserve deadspace gases and get rid of alveolar gases.
Can conserve FGF's of 70% of tidal volume
Inefficient for PPV |
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Term
| What are some disadvantages of the Mapleson systems? |
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Definition
High FGF
Pollution of OR
Loss of pt heat and humidity |
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Term
| Explain the closed system |
|
Definition
Patients gases re-circulate because there is a soda lime co2 absorber.
Has insp and exp one way valves
Saves FGF's so less expesive
Because it's a closed system, don't worry as much about scavenged gases |
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Term
| What are the classification systems of Mapleson Systems? |
|
Definition
A- Magill
B- Not in use
C- Waters to and fro system
D- Bain
E- Ayre's T piece
F- Ayre's T piece with open ended bag |
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Term
| Which Mapleson system is best for spontaneous breathing |
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Definition
|
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Term
| Which Mapleson system is best for peds and controlled ventilation? |
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Definition
|
|
Term
| What is Scavenging of gases? |
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Definition
| Removal of toxic gases or anesthetic gases from OR |
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Term
| What are the two types of scavenging systems? |
|
Definition
Active - energy required for a vacume system - common
Passive - pt exhale used to pump gases out passively to outside. - bad |
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Term
| What are the three components of a modern scavenging system |
|
Definition
Transfer system - tubing
Receiving System - reservoir, flow indicator, flexible hose
Disposal system - centralized vacuum (active system), independent system recommended, ensure positive and negative pressure are controlled |
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Term
| How many air changes per hour in OR scavenging system? |
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Definition
|
|
Term
| Number of neutrons determines what? |
|
Definition
|
|
Term
| Number of protons determines what? |
|
Definition
|
|
Term
| What is an unstable nucleus of an isotope? |
|
Definition
radionuclide
it may degenerate into another atom |
|
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Term
|
Definition
| an element changing into another |
|
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Term
| What is an alpha particle? Beta? |
|
Definition
Alpha - 2 protons and 2 neutrons
Beta - electron may be emitted |
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|
Term
| Are gamma rays particles? |
|
Definition
| No, electromagnetic waves |
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|
Term
| What is the SI unit of radioactivity? |
|
Definition
Becquerel
one disintegration of a nucleus per second |
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Term
| How is duration of radioactivity defined? |
|
Definition
half-life - the time it takes half of the material to decay.
Rate of decay depends on the amount present - exponential. As quantity increases, so does decay.... |
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Term
| How is radiation detected? |
|
Definition
|
|
Term
| What are radionuclides used for in medicine? |
|
Definition
Treatment of tumors (external and internal)
Iodine 131 treats thyrotoxycosis (internal) |
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|
Term
| What is used for regional ventilation imaging? |
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Definition
|
|
Term
| What are x-rays similar to? |
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Definition
|
|
Term
| What is important to know regarding radiation safety? |
|
Definition
all exposure may cause tissue and chromosomal damage
Keep exposure to minimum
Effects are inversely proportional to the square of the distance from the source
Wear radiation badges |
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Term
| What is more dangerous ionizing or non-ionizing radiation? |
|
Definition
Ionizing (x-rays, gamma rays etc)
non-ionizing - radio waves, microwaves etc
Except lasers which are non-ionizing) |
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Term
|
Definition
| intense collimated beam of light or electromagnetic radiation |
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Term
| What are the two energy sources in a laser |
|
Definition
|
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Term
|
Definition
|
|
Term
| What materials are not safe for MRI? |
|
Definition
|
|
Term
| What is the percent occurrence of Awareness? and when does it usually occur? |
|
Definition
0.01% 1 in 1000
Trauma or cardiac patients |
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Term
| What are requirements for satisfactory anesthesisa? |
|
Definition
- Adequate hemodynamic stability
- No patient movement
- no awareness - no recall
- similar values for different anesthetics
- Appropriate change during surgical stimulation
- marked difference in the signal between consciousness and unconsciousness |
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Term
| What is the most important clinical sign for adequate anesthesia? |
|
Definition
| Patient movement. Therefore try not to paralyze unless absolutely necessary. |
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Term
| What does the EEG show in anesthesia? |
|
Definition
- deepening of anesthesia usually accompanied by decrease in frequency and amplitude
- burst suppression occurs at deep levels of anesthesia |
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Term
| What are the two different types of Compressed Spectral Array used? (CSA) |
|
Definition
Spectral Edge Frequency
Median Frequency |
|
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Term
| What is the PRST score based on? |
|
Definition
| SBP, Pulse, Tearing, Sweating |
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Term
| What are the most common indicators to increase or decrease amt of anesthetic? |
|
Definition
| Arterial pressure and heart rate. |
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Term
| In a CSA, where does the power shift to in anesthesia? |
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Definition
|
|
Term
| Which of the two CSA's are more accurate? |
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Definition
|
|
Term
| What relationships are the BIS monitor based on? |
|
Definition
|
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Term
|
Definition
measure of the phase relationship between frequency triplets
increases with anesthesia |
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Term
| What does the bicoherence index calculate? |
|
Definition
weighted average of spectral array
bicoerence
burst supression |
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|
Term
| What is the auditory evoked potential |
|
Definition
| based on fact that hearing is the last thing to go under anesthesia. Amplitude diminishes with increasing anesthesia |
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Term
| What are evoked potentials used for? |
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Definition
| determining cohesion of pathways. As you deepen anesthesia, less correlation. |
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Term
| What patients are at risk for a recall event? |
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Definition
| Cardiac, trauma, drug abusers, alcoholics |
|
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Term
| What are the three things most important for monitoring depth of anesthesia |
|
Definition
BP and HR
Patient Movement
MAC |
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