Flashcards in Co2 monitoring Deck (18):
Indications for non-invasive C02 monitoring
-Check for ETT position – Tracheal? Esophageal?
Note : CO2 detection does not assure correct placement
-Reduce trauma to targeted blood vessel, if can’t obtain sample, in neonates
-Allow for continuous monitoring
What are 2 devices for non-invasive C02 monitoring?
-End Tidal CO2 (ETCO2) Monitoring
What are the 2 methods that Capnometers sample gas?
Mainstream (analyses the c02 in line)
Sidestream (takes a sample of gas from the line and sends it to analyzer)
With regards to Pac02 and Petco2 levels, what readings can you expect to see when comparing the 2 in healthy and un-healthy lungs?
In healthy lungs, they should be the same but can have a petCo2 level about 5 lower than Pac02.
in un-healthy lungs, Pac02 can be much higher due to heterogeneous degrees of lung tissue with inability to remove it due to decreased perfusion.
When reading a capnograph, explain phase 1,2,3
Phase 1 - after the end of inhalation, patient is exhaling dead space, mostly 02
Phase 2 - deadspace gas and gas coming from alveoli are mixing creating a spike in graph.
Phase 3 - This is the plateau phase where the remaining gas from the alveolar level is being exhaled. right before inhalation and steep drop.
What can cause an elevated baseline in a capnograph?
What can cause a Petc02 level of 0 or near 0?
What can cause a sudden rise in Petc02?
-sudden increase in Cardiac output
-sudden release of a tourniquet
-injection of Bi-Carb
What can cause a sudden decrease in petco2?
(4 patient symptoms or conditions)
DISCONNECTION FROM VENT
OBSTRUCTION OF ETT TUBE
sudden decrease in cardiac output
massive pulmonary embolism
What can cause a gradual rise in Petco2?
increase in co2 production
What can cause a gradual decrease in Petco2?
decrease in 02 consumption
decrease pulmonary perfusion
How is Petco2 measured?
colormetric techniques (intubation kit)
mass spectrometry (less common, more expensive)
What can cause false positive readings on a colormetric c02 detector?
how can you tell the difference?
-drugs like lidocaine or epi
false positives change it permanently. normally it should change it breath by breath
What are some causes of false negatives?
patients with low cardiac output.
What is the normal value for dead space/tidal vol? (Vd/Vt)
Critical is greater than .60
What happens on a bi-phasic wave on a capnograph?
Where areas of the lung have very different time constants and V/Q ratios
exhalation will plateau but the patient wants to take in another breath. this will momentarily drop the wave but instantly rise.
A patient in the OR who's paralytics are wearing off would show what capnograph wave abnormality?
Patient will take a weak breath during exhalation