Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
SIUE: Monitoring
Kevin's lecture 10/19 - Inspiratory & Expiratory monitoring
| Question | Answer |
|---|---|
| Four key features for monitoring | 1.) Proper instrumentation 2.) observation & vigilance 3.) interpretation of data 4.) initiation of corrective therapy |
| What is Standard I of Anesthesia Monitoring from ASA | Qualified personnel continuously present to monitor the patient and make neccessary modification |
| What is Standard II of Anesthesia Monitoring from ASA | Continuously evaluating the patient's oxygenation, ventilation, circulation, and temperature |
| High tone on alarm usually indicates | good perfusion |
| Low tone on alarm usually indicates | poor perfusion |
| In the anesthesia circuit, what must be measured | inspired and expired gases |
| Just because the concentration of O2 in the anesthesia circuit is measured it doesn't gaurantee what? | The adequacy of arterial oxygenation |
| O2 sensors are located where on the anesthesia limb | Inspiratory limb, closer to the machine than patient |
| O2 sensors protects against | hypoxic mixtures |
| 3 types of O2 analyzers | 1.) Galvanic cell analyzer 2.) Polargraphic O2 analyzer 3.) Paramagnetic O2 analysis |
| O2 is considered a highly | pragmatic gas - attracted to magnetic energy because of unpaired electrons in their outer shell. |
| Paramagnetic O2 analyzer | Dumbell filled with inert gas and suspended on platinum wire. When O2 is processed through sensor, O2 molecules are attracted to stronger of 2 mag fields - resulting in dumbell rotating. Degree of rotation is directly porportional to the PP of O2. |
| In the paramagnetic O2 analyzer more current required to keep the in a normal state the | higher the % of O2 |
| Galvanic Cell Analyzer | O2 analyzer. Electrochem sensor. anode and cathod are immersed in electrolyte solution of potassium hydroxide. Hydroxyl ion migrates to anode where oxidation takes place generating an electrical current proportional to the O2 concentration. |
| Galvanic Cell Analyzer are recognized for their | accuracy |
| Polarographic O2 analyzer | Anode and Cathode are immersed in potassium chloride, molecular O2 is consumed by sensor with an accompanying flow of electrical current directly prop. to O2 concentration |
| Most common O2 analyzer used in anesthesia | Polargraphic O2 analyzer, because its the sensor of choice for measuring dissolved O2 measured in liquids |
| Which O2 analyzer is most similar to the galvanic O2 analyzer | Polargraphic O2 sensor |
| 3 ways to measure expired gas | 1.) infrared absorption spectophotometry 2.) mass spectrometry 3.) Raman scattering techniques |
| Where does the sampling of expired gas occuring at? | near the ET tube, closer to patient than the O2 analysis |
| Infrared Absorption Spectrophotometry IRAS is based on the fact that | asymmetric molecules absorb infrared light at specific wavelengths |
| IRAS CAN detect & measure | CO2, N2O, and the inhalation anesthetic agents |
| Fall back to the IRAS | cannot distinguish which specific gas is which. (cannot tell if des or sevo), because all anesthetic vapors absorb infrared light at the same wavelengths |
| All anesthetic vapors absorb infrared light at | the same wavelengths |
| 5 components of IRAS | 1.) infrared light source 2.) gas sampler 3.) optical path 4.) detection system 5.) signal processor |
| IRAS measures the unique energy absorbed by gaes and vaports placed into what? | an optical path of infrared beam |
| IRAS has a memory system that | correlates absorbed energy with a predicted concentration based upon the Beer-Lambert Law |
| Mass Spectrometry | expired gas measurement. Gas mixure is bombarded with electrons which break them down into fragments given a mass and charge. Then frags are accelerated into a vaccum passing a magnetic field, they separate by mass & charge which are detected. |
| In mass spectrometry, there is calculation of ion/mass charge ration based on | variance of deflection. Each gas has a specific landing site on the detector plate. Ion impacts are prop to concentration of each gas or vapor |
| Raman Scattering | expired gas monitoring. A high intensity argon laser collides with gas molecules which causes increased vibration of the gas moecules. Can identify O2, CO2, N2, N20 & all volatile anesthetics |
| Raman scattering advantages | can identify 02, CO2, N2, N20, all volatile anesthetics and mixtures of volatile anesthetics. very fast, easy to calibrate. |
| CO2 monitoring can be useful for detecting alterations in | ventilation, cardiac output, distribution of pulmonary blood flow, and metabolic activity |
| Capnometry | measurement of CO2 concentration NUMERICALLY, during inspiration and expiration |
| Capnogram | waveform display, continuous concentration-time display of CO2 concentration during ventilation |
| Capnography | the continuous monitoring (continuous waveforom) of the capnogram |
| Capnography is important because it | identifies changes related to patients physiologic status, used to dx malig. hyperthermia, helps identify equip problems, gold standard for ET tube placement, predicts PaCO2. |
| What is the gold standard for verifying ET tube placement | capnography |
| Capnometry is determined using | infared light, with 2 different wavelengths (2600nm & 4300nm). Control gas is comparted to sample from the circuit and a NUMBER is resulted |
| Capnogram component A-B | valley, or baseline. Represents end of inspiration and the begining of expiration. Considered the initial state of expiration. No CO2 here (why a-b is norm at zero) because of gas sample is from the dead space where is is devoid of CO2 |
| Capnogram component B | begining of the upstroke, where CO2 presents itself |
| Capnogram component B-C | Sharp upstroke of exhalation. Gas sampld represent a mix of deadspace & alveolar gas thus measurable CO2 is available |
| the slope of B-C is determined by | the eveness of ventilation & alveolar emptying |
| Capnogram component C-D | the alveolar or expiratory plateau. Normally horizontal. |
| Capnogram component D | highest CO2 value of ETCO2 because at end of plateau before inspiration occurs. best reflection of alveolar CO2. |
| Capnogram component D-E | inspiration begins,steep downstroke (rapid decrease in CO2) fresh gas entrained. |
| ETCO2 may be inaccurate in the presence of significant | V/Q mismatch |
| If V/Q mismatch ratio is large, from embolism this results in ____ of ETCO2 | an decrease in ETCO2 and increase in deadspace |
| Small tidal volumes may relfect inadequate alveolar ventilation and produce ETCO2 readings that | significately underestimate arterial CO2 levels |
| A waveform on capnography that fails to return to baseline, reveals that the patient is ____? which could be from? | retaining CO2. Result of inadequate fresh flows or need to change soda lime absorber (CO2 scrubber). |
| Following esophageal intubation what will we see on the capnogram | a initial slight upstroke of CO2, then waveform goes to zero |
| sloping of the plateau phase represents | a progressing prolongation of expiration, from either an obstruction from V/Q mismatch or can be indicative of COPD, or tube kinking |
| Sawtooth waves on inspiratory down stroke is a result of | cardiac oscillations. common in pediatric patients, or is patient is begining to wake up at end of case. |
| Curare cleft is what and when is it seen | it is a dip in the middle of plateau segment, from spontaneous respiratiory effort. Pt needs more narcs or anesthetic. |
| PaCO2 is measurement of CO2 in | the arteries |
| PACO2 is measurement of CO2 in the | alveoli |
| In what case might the canogram be not as useful as normal? | In a case of pulmonary disease, because CO2 might not diffuse as easily, or ventilation & perfusion are not matched |
| Capnography provides non-invasive what? | continuous, real-time reflection of ventilation |
| During general anesthesia ETCO2 is typically | 5-10mmg LOWER than PaCO2. |
| So under anesthesia if my ETCO2 is 35, what is the PaCO2 | PaCO2 is 40-45mmHg |
| When might the accuracy of the ETCO2 and PaO2 relationship decrease | 1.) maldistribution of V/Q 2.) problems in gas sampling 3.) shallow tidal breaths 4.) prolongation of expiratory phase of ventilation 5.) uneven alveolar emptying |
| If you have a non-perfused alveoli you will have a higher or lower ETCO2? and a PaCO2 of what? | lower ETCO2 reading, and a PaCO2 reading of 0. |
| If someone has a V/Q mismatch what happens to the PaCO2 - ETCO2 gradient | it will increase (meaning there will be more than a 5-10 difference between the two) |
| Examples of V/Q mismatch? | emboli, hypoperfusion sates with reduced pulmonary blood flow, COPD |
| What is the standard of care for oxygenation monitoring during anesthesia? | Pulse oximetry |
| Pulse oximetry measures | pulse rate via plethysmography & oxygen saturation of hemoglobin using spectrophotometry |
| Most accurate measurement of pulse Ox is when probe is | applied to R ear |
| Goal of pulse ox is to | detect early hypoxemia and initated tx before serious complications occur |
| Pulse ox is based on several premises | 1.) color of blood is a function of o2 sat 2.) the change i ncolor resuls from optical properties of Hbg interaction with O2 3.) Oxyhemoglobin:deoxyhemoglobin can be determined by absorption spectrophotometry |
| pulse oximetry and blood gases assess | arterial oxygen |
| Steps for reading a capnogram | 1.) look at y axis (is CO2 norm range 35-45) 2.) look at your x axis (is CO2 returning to baseline with each breath 3.) look at expiratory upstroke and inspiratory downstroke (are they normal?) 4. Look at RR rate (is it normal) |
| Factors to increase ETCO2 | shivering, malignant hyperthermia, increased CO, bicarb infusion, effective tx of bronchospasm, decreased minute ventilation |
| Factors to DECREASE ETCO2 | decreased muscular activity, hypothermia, decreased CO, pulmonary embolism, bronchospasm, incresed minute ventilation |
| Capnography uses: | determine ET vs tracheal intubation, monitor changes in dead space or perfusion, used to dectect ciruit issues and leaks |
| We would expect and increase in ETCO2 when CO2 production | exceeds ventilation |
| Spectrophotometry of pulse ox based on beer lambers law says | at a consant light intentisity and hbg concentration, the intensity of light emitted through tissue is a logarthimic function of the O2 satuaration of the hgb |
| spectrophotometry of pulse ox includes | 2 wavelengths to distinguish between deoxyhemoglobin and oxyhemoglobin. The ratio of deoxyhgb : oxyhbg is determined by measuring the ration of infrared and red light sensed |
| Oxyhemoglobin absorbs | infrared light (940nm) |
| Deoxyhemoblobin absorbs | red light (660nm) |
| Sa02 is ______ to Sp02 | NOT EQUAL |
| Sp02 will not distinguish between | 02 Hb and carboxyhemoglobin or methemoglobin |
| Methemoglobin Sp02 will measure what and why? | Sp02 of 85 because it absorbs infrared and red light equally |
| Carboxyhemoglobin SpO2 will meausre | false high (absorbs light at the same wavelength, normally the infrared oxyhemoglobin is faster) |
| Factors that decreased pulse ox reliability | dyshemoglobins, low CO, anemia, vital dyes (methylene blue & indocarmine), nail polish, ambient liht, light emitting diode variability, motion artifact, background noise |
| A smokers pulse ox reading is usually | a false high, smokers Sp02 is 7 points below what they read |
| Pulse Ox troubleshooting | is red light visible, is there thickening of skin on site, cold or vasoconstriction, pt moving or shivering, surgeon using cautery, room light interference, fake nails or dark polish, is there a pulse? |
| Oxyhemoglobin dissociation curve | measures the relationship of hemoblogin saturation & O2 tension |
| On the steep part of the oxyhemoblogin curve what predictable correlation exists | between PO2 and Sa02 |
| Shifts in the curve to the right or left define changes in the | affinity of Hb for O2 |
| Causes of LEFT shift in oxyhemoglobin diss. curve | increased pH (alkalosis), decreased temp, decreased PaCO2 |
| Causes of a RIGHT shift in the oxyhemoglobin diss curve | decreased pH (acidosis, increased temp, increased PaCO2 |
| normal oyxhemoglobin diss curve predictions of SP02 & Pa02 | Sp02 97% = Pa02 97%, Sp02 90% = Pa02 60%, Sp02 80% = Pa02 50%, Sp02 70% = Pa02 40% |
| If patient is at risk for malignant hyperthermia precautions would be | change entire curciut out including CO2 scrubber, run 10L O2 for 60 min prior, use total IV anesthesia if has had MH in the past. |
Created by:
asaranita
Popular Nursing sets