Monitoring Flashcards
What is dynamic compliance?
Compliance of the lung and chest wall DURING MOVEMENT
What is static compliance?
Lung compliance while there is no airflow. It’s a function of the natural tendency of the lung/chest wall to collapse
What is plateau pressure?
Pressure in the small airways and alveoli after the target TV has been delivered.
There is NO airflow at this time, so it’s value is NOT a function of airway resistance. It instead reflects the elastic recoil of lungs and thorax during the inspiratory pause –> at this point the pressures of the lung and chest wall wanting to collapse and the pressure within the lung are equal.
Risk of barotrauma exists when plateau pressures are > ____
35cmH2O
O2 blood absorbs this wavelength
Deoxygenated blood absorbs this wavelength
O2 = 990nm (near-infrared) Deox = 660 (red)
Higher O2 content = higher wavelength
Pulse oximetry is based on this Law
Beer-Lambert:
- related to the intensity of light trimmed through a solution and the concentration of the solute within the solution.
Can pulse ox be used to look at pulse pressure variation (PPV%)?
Yes
Does pulse ox account for O2 dissolved in blood?
No
Does jaundice affect pulse ox readings?
No
Methemoglobin
Fe3+
Absorbs 990 and 660 equally
Thus, it falsely underestimates SpO2 when sat is >85%
Falsely overestimates SpO2 when
Carboxyhemoglobin
CO-Hbg (carbon monoxide)
Pulse Ox reads CO-Hgb and O2-Hgb the same. Thus, it overestimates saturation.
This is the most common method of analyzing exhaled gas in the OR
Infrared absorption
How is O2 analyzed?
O2 does not absorb infrared light, so it must be measured by electrochemical means (Galvanic Cell or Clark Electrodes) or paramagnetic analysis
The ideal BP bladder WIDTH is ___% the circumference of the pt’s arm
40%
The ideal BP blade LENGTH is ___% the circumference of the pt’s arm
80%
Do a-lines measure pressure at the site of insertion or level of transducer?
Level of transducer
Most common complication while obtaining CV access
Dysrhythmias
This is the classic presentation of PA rupture
Hemopytsis
This is the point of phlebostatic access
Mid anteroposterior level at 4th intercostal space
Where in the respiratory cycle should CVP be measured?
End expiration
Meanings of high and low CVP
Low CVP is easy: either transducer is too high or the pt is hypovolemic.
If CVP is too high, could be a million things related to
1) Hypervolemia
2) Decreased ventricular compliance
3) Increased intrathoracic pressure