What is included in Standard V (monitoring?
A.) ventilation B.) oxygenation C.) CV status D.) body temp E.) neuromuscular function and status F.) patient positioning
What is absolutely required to monitor ventilation?
Pulse ox
ETO2
(Both continuously)
What are indications for using a precordial/esophageal stethoscope?
Since it provides continuous auditory confirmation of ventilation., quality of breath sounds, HR regularity, and quality of heart tones it is useful in detecting subtle changes
—> muffled hearts tones are associated with decreased CO
(Also has temp probe built into it)
When is using an esophageal stethoscope contraindicated?
If pt has a hx of esophageal varies, strictures or bariatric surgery
What happens if esophageal stethoscope slides into trachea, and what do you do if this happens?
A gas leak will occur around ETT
—> pull esophageal catheter out/back and start over
What are the 2 wavelengths of light in a pulse ox?
Red: 660nm—> absorbed by deoxyhemoglobin
Infrared: 940 nm—> absorbed by oxyhemoglobin
How does a pulse ox calculate O2 sats?
Is it ever contraindicated to use a pulse ox?
Calculates both fractions of deoxyhemoglobin to oxyhemoglobin passing through an arterial bed
- ratio of 660:940 light
No- use it!
What is Beer Lambert’s Law?
Basis for how we do oxygen saturation
-in red region oxyhgb. Absorbs less light than deoxyhgb. And vice versa
What are some reasons for inaccurate pulse ox readings?
- vasoconstriction
- hypothermia
- hypotension
- methylene blue: messes with absorption of light sensor, usually transient-does not mean a real drop in O2
- methemoglobin-absorbs light equally to oxyhemoglobin
- carboxyhemoglobin-attaches well to RBC- will show 100% sat, not all of this is O2. PaO2 will be very low
- sickle cells
How does ETCO2/capnography work?
Uses infrared
- continuous waveform of inhaled and exhaled concentration of CO2
- waveform provides info on adequacy of ventilation and confirms ETT placement in respiratory tract
What does the absence of an ETCO2 waveform mean?
- esophageal intubation
- disconnect from circuit/breathing system
- cardiac arrest
- air emboli
How accurate is ETCO2 compared to PaCO2?
ETCO2 is 2-5 torr less than arterial PaO2
- gap widens in smokers (can’t fully exhale)
In the capnography waveform what does phase I (A-B) represent?
Exhalation of deadspace
In the capnography waveform what does phase II (B-C) represent?
Exhalation of deadspace and alveolar gas
In the capnography waveform what does phase III (C-D) represent?
Exhalation of alveolar gas
In the capnography waveform what does phase IV (D-E) represent?
Inspiration of fresh gas, not containing CO2- return of wave to baseline
Other than the pulse ox, what are additional respiratory monitors?
Multiple gas analyzers
- continuous analysis of inhaled and exhaled concentrations of respiratory and anesthetic gases (no contraindications)
What is mass spectrometry and how is it used regarding anesthesia gases?
Gas is bombarded with electrons—> this creates fragments of charged particles
- these particles are separated and identified based on mass
- type and concentration of gas can be determined (from an exhaled gas sample to determine amt gas exhaled…ETCO2
Can mass spectrometry analyze more than one pt at a time?
Yes, up to 32 pts can be anazlyzed on 1 central computer
- as of 1975 so longer produced, but still may be used in places
What is Raman spectroscopy?
High power argan laser produces photons that collide with gas molecules
- scattered photons are measure in a spectrum that identifies each gas and its concentration
- measures “Raman scattered light” from these gases
What is monochromatic infrared Spectrometry?
infrared beam with wavelength of 3.3nm is passed through a gas sample
- the absorbed spectrum of halogenated gases is similar at this wavelength
- monitor must be programmed with selected agent
- concentration of gas is then measured
What is polychromatic infrared spectrometry?
- infrared beam at 7-13 nm is passed through anesthetic gas sample
- absorption spectrum of halogenated gases is different at this wavelength
- monitor automatically identifies inhaled agent and can describe concentrations given
- if you change agents- the monitor can measure both simultaneously
How do you monitor positive pressure created by mechanical ventilation?
Peak inspiratory pressure gauge
How does the peak insp pressure gauge monitor low pressure disconnect?
- alarm indicates minimum inspired pressure did not achieve pre determined level
- caused by disconnect or leak in breathing system
- increases with insuflation—> expected to happen
- caused by disconnect or leak in breathing system
