Week 1 - Basic Clinical Monitoring (Respiratory & Metabolic) Flashcards
(62 cards)
Cyanosis is a _________ sign of hypoxia
late
PaCO2 is based on _____________ concentration
hydrogen ion
Carbon dioxide reacts with water to produce _________
carbonic acid ——> hydrogen ions
reversible reaction - basis for respiratory involvement in pH balance
How does a colorimetric device work to monitor ventilation following intubation?
Exhaled CO2 reacts with water in the device to form carbonic acid - this raises the pH and changes the color on the indicator
What are the limitations of colorimetric devices used following intubation?
False positives may result from detection of CO2 from air forced into the stomach (or from the presence of carbonated beverages or antacids)
ETCO2 is said to be approximately _______ torr lower than arterial CO2
2-5
this is true for patients without cardiac or pulmonary abnormalities
ETCO2 has been shown to be a ________ sensitive indicator of hypoventilation than clinical observation or pulse oximetry
more
In the following capnogram, what does the segment from B to C represent?
Beginning of expiration
At which point on the capnogram is the ETCO2 measured? What is this called?
point D
* this is termed the Beta angle
How would you interpret the following capnogram?
There is a failure to return to baseline which indicates CO2 rebreathing
What effect would sustained hyperventilation have on ETCO2?
it would decrease
* (there is an initial increase as there is a large amount of CO2, but sustained hyperventilation causes a decrease as the blood content of CO2 is depleted)
What effect would sustained hypoventilation have on ETCO2?
it would increase
* (there is an initial decrease as exhalations are small, but over time the body compensates by removing a greater amount of CO2 with each breath)
In a patient with fever or sepsis, would you expect an increase or decrease in ETCO2?
Increase
* these states cause the body’s metabolic rate to increase - leading to greater production of CO2 at cellular level and a greater degree of CO2 removal with each exhalation
In a patient with pulmonary emolism, what change in ETCO2 might you expect?
Decrease
* this is due to a decreased delivery of CO2 to the alveoli
What might the following capnogram represent?
Asynchrony with ventilator/return of spontaneous ventilation
In states of __________ compliance, minimal force is needed for lung expansion
high
not necessarily a good thing (COPD, Emphysema)
When compliance is low _________ force is needed for lung expansion
more/higher
Lung _______ can be shown by a flow/volume loop
compliance
The following flow volume loop is characteristic of _________ lung disease
obstructive (air can’t get out)
* near normal inhalational volume and flow (bottom half of loop), but severely limited exhalational volume and flow (top half of loop)
* e.g. COPD, emphysema
Because oxyhemoglobin absorbs light differently than deoxyhemoglobin, oxygen saturation can be measured via ___________
pulse oximetry
In the presence of methemoglobin or carboxyhemoglobin, or a patient with sickle cell anemia, a pulse oximeter may falsely _________-estimate the true value of oxygen saturation
over
* methemoglobin and carboxyhemoglobin absorb light in a way similar to oxyhemoglobin - this fools the pulse oximeter into thinking that saturation is normal when the true value is low
The presence of dyes, such as methylene blue, alters the absorbtion of light by a pulse oximeter - this may cause a transient ___________ in measured oxygen saturation
decrease
Hypothermia is defined as a core temperature of less than _______
36 degrees celsius
How do general anesthetics alter thermoregulation?
Reduce shivering
Reduce vasoconstriction (normal vasoconstriction would conserve heat)
