Respiratory Monitors Flashcards
What is compliance ?
-Change in volume for a given change in pressure
-Measures elastic properties of the lungs
What things influence compliance?
Muscle Tone
Degree of lung inflation
Alveolar surface tension
Amount of interstitial lung water
Pulmonary fibrosis
What is dynamic compliance?
Movement of the lung and chest wall
What is static compliance?
Not moving
Measures lung compliance when there is no air flow
What is the Peak Inspiratory Pressure or PIP?
Maximum pressure in the airway during inspiration
Also Dynamic compliance
Dynamic compliance = Tv / PIP-PEEP
What is the plateau pressure?
The pressure in the small airways after the Tv is delivered
Also Static compliance
**NO airflow
**Airway resistance does not effect
PIP or Plateau - Which is measures with no airflow?
Plateau (Static)
PIP or Plateau - Which does airway resistance effect?
PIP (Dynamic)
In an adult what is normal static compliance? In a child?
Adult 35-100
Child >15
PIP or Plateau - Which has a proven effect on barotrauma?
Plateau
PIP has controversial evidence
Examples of an increased Resistance? or Dynamic compliance? or PIP?
Kinked tube
ET cuff rupture
Bronchospasm
Compression of airways
Foreign body aspiration
Examples of Decreased compliance?
Endobronchial intubation
Pulmonary edema
Pleural effusion
Tension Pneumo
Atelectasis
Ascites
Trendelenburg
What type of compliance is a function of the elasticity of the chest wall only?
Static
What is the formula for static compliance?
Static = Tv / Plateau - PEEP
What is the formula for dynamic compliance?
Dynamic = Tv / PIP - PEEP
On the Capnograph, Where is the end-tidal measured?
Point D (end of expiration)
On the Capnograph, What is Phase 1?
It is the flat line
Exhalation of anatomic dead space
On the Capnograph, What is Phase 2?
Upstroke
Exhalation of anatomic dead space + alveolar gas
On the Capnograph, What is Phase 3?
Flat top line
Exhalation of alveolar gas
On the Capnograph, What is Phase 4?
Downstroke
Inspiration of fresh gas
What is the Alpha angle? Normal? What diseases can cause an increased Alpha Angle?
Normal 100-110 degrees
Obstruction
-COPD
-Bronchospasm
-Kinked tube
What is the Beta angle? Normal? What diseases can cause an increased Beta Angle?
90 Degrees
Rebreathing
-Specific to bad inspiratory valve
What is the mainstream (In line) monitor?
-Faster response
-NO water trap or pumping
-INCREASES dead space
What is the side stream (diverting) monitor?
-Has pumping and a water trap to prevent contamination
-SLOWER response time
Review capnograph photos
What requirements must be met to detect CO2
CO2 must be produced during metabolism
Adequate pulmonary blood flow
Adequate ventilation to transport to circuit
Intact sampling line
What does a wide AA gradient signify?
V/Q mismatch
-Equipment malfunction
Does an incompetent unidirectional valve increase or decrease EtCO2?
Increase
Does a tourniquet removal increase or decrease EtCO2?
Increase
Does an airway obstruction increase or decrease EtCO2?
Decrease
Does thyrotoxicosis increase or decrease EtCO2?
Increase
Does MH increase or decrease EtCO2?
Increase
Does an increase in apparatus dead space increase or decrease EtCO2?
increase
Does a V/Q mismatch increase or decrease EtCO2?
Decrease
Does hypotension increase or decrease EtCO2?
Decrease
Does hypothermia increase or decrease EtCO2?
Decrease
Does a PE increase or decrease EtCO2?
Decrease
Does decreased CO increase or decrease EtCO2?
Decrease
Does a laparoscopy increase or decrease EtCO2?
Increase
Does esophageal intubation increase or decrease EtCO2?
Decrease
Does opioid overdose increase or decrease EtCO2?
Increase
Does metabolic acidosis increase or decrease EtCO2?
Decrease
Does metabolic alkalosis increase or decrease EtCO2?
Increase
Does sodium bicarb increase or decrease EtCO2?
Increase
What waveform does oxygenated Hgb absorb light?
940nm (Near infrared)
What waveform does deoxygenated Hgb absorb light?
660nm (Red light)
On the waveform, where is the highest ratio atrial to venous blood?
At the peak (Increased)
On the waveform, where is the where is there a greater amount of venous blood?
At the trough
Peak has higher arterial
Where the sites to most to least responsive to arterial desaturation?
Fastest - Ear, nose, tongue, esophagus, forehead
Middle - Finger
Slow - Toe
Closer to central circulation the better
If the pulse ox reads 90%, what is the PaO2?
30 point difference
PaO2 - 60
SpO2 80% = PaO2 50
SpO2 70% = PaO2 40
What methods can improve SpO2 signal?
Digital Block
Warm the extremity
Vasodilate
Protect from light
How does chronic anemia effect the oxyhemoglobin curve?
Shifts R
How does MH effect the oxyhemoglobin curve?
Shifts R
How does Methemoglobin and carboxy effect the oxyhemoglobin curve?
Shifts L
How does Increased pH or acidosis effect the oxyhemoglobin curve?
Shifts L
How does thyroid storm effect the oxyhemoglobin curve?
Shifts R
How does hypoxia effect the oxyhemoglobin curve?
Shifts R
How does Pyrexia effect the oxyhemoglobin curve?
Shifts R
Does a Pulse Ox monitor for anemia?
No
Does a Pulse Ox monitor for ventilation?
No
Does a Pulse Ox monitor for bronchial intubation?
No
Does a Pulse Ox monitor for flid responsiveness?
Yes
Does a Pulse Ox monitor for Hgb saturation or HR?
Yes
Does a Pulse Ox monitor for peripheral perfusion?
Yes
Is a pulse ox useful for patients with a VAD?
No
Do acrylic nails effect pulse ox?
No
What color nails do not effect a pulse ox?
Red and Purple do not
How does methemoglobin effect the pulse ox?
Absorbs light equally at 660 and 940
Will read 85% so could be high or low
How does carboxyhemoglobin effect the pulse ox?
Absorbs at 660 so will be falsely high
What is the acceptable margin of the pulse?
2-3%
What is the most common way to measure exhaled gases?
Infared absorption
How does shivering and tricuspid regurg effect the SpO2?
Falsely reduce SpO2
What decreases the AA gradient?
A stuck or incompetent unidirectional valve
Will see an increase in PaCO2 and EtCO2 but the gradient gets smaller
What increases the AA gradient?
Increased Dead Space
Ex: Venous air embolism
Which monitor can not monitor O2 concentration?
Infrared absorption
Which monitors can monitor O2 concentration?
Electrochemical analysis and paramagnetic
Does fluorescein effect pulse ox?
No