Breathing Circuits & Respiratory Monitoring Flashcards
1
Q
Patient is rebreathing CO2 what 2 interventions can you do to fix the issue?
A
- replace the CO2 absorbent
- increase your FGFs (convert to semi-open system)
2
Q
Mapleson Circuits (6 total): all with risk of rebreathing
- Best for spontaneous ventilation? Worst?
- Best for controlled ventilation? Worst?
- Circuit with no APL valve or reservoir bag?
A
- Mapleson A, Mapleson B
- Mapleson D, Mapleson A (requires ~20 L/min of FGF for CV)
- Mapleson E
3
Q
The Bain Circuit: uses a coaxial design
- Fresh gas is delivered to the patient through the ___
- Exhaled gas travels through the ___
- This is a modified Mapleson ___
- It is used for both SV and CV, to prevent rebreathing FGF should be ___ minute ventilation
A
- inner tube
- outer tube
- Mapleson D
- 2.5x MV
4
Q
Bain System:
- The inner tube is at risk for kinking and disconnection-perform ___ (occlude elbow at patient end, close APL valve, fill circuit with O2 flush, remove occlusion at elbow while flushing)
- Safe to use circuit if reservoir bag ___ (cause by Venturi effect)
A
- Pethick Test
- collapses (don’t use if remains inflated)
5
Q
Compliance:
- Measures the change in ___ for a given change in ___
- Measure the?
- Influenced by muscle tone, degree of lung inflation, alveolar surface tension, amount of interstitial lung water, pulmonary fibrosis
A
- volume for a given change in pressure
- elastic properties of the lungs and chest wall
6
Q
- ___ = This is the max pressure in patients airway during inspiration. Affected by airway resistance and chest/lung compliance due to air flowing into airway during inspiration.
- ___ = This is the pressure in small airways and alveoli after target TV delivered. No airflow at this time thus airway resistance does not affect this.
A
- Peak inspiratory pressure (PIP)
- Plateau pressure (PP)
7
Q
Plateau Pressure:
- This reflects the elastic recoil of lungs and thorax during inspiratory pause (no gas movement)
- Barotrauma risk increases when PP exceeds ___. If barotrauma exists aim to reduce PP by reducing ___, ___, and ___. ___ also helps.
- Complications of increased PP include (4)
A
- 35 cm H2O
- TV, inspiratory flow, PEEP, sedation
- vent assoc lung injury, pneumothorax, pneumomediastinum, subcutaneous emphysema
8
Q
- If increased PIP and increased PP then __ or TV has increased.
- If increased PIP and no change in PP then __ or inspiratory flow rate has increased.
A
- Total compliance has decreased (endobronchial intubation, pulm edema, pneumo, atelectasis, ascites, T-berg, inadeq. MR)
- airway resistance has increased (kinked ETT, bronchospasm, bronchial secretions, aspiration of foreign body, ETT cuff herniation)
9
Q
- **Alpha angle = ?
- Measured at Point ?
- Normally 100-110 degrees, if increased suspect (3)
- **Beta angle = ?
- Measured at Point ?
- Normally 90 degree angle, if increased patient breathing FG and CO2
A
- **Airflow obstruction
- Point C
- COPD, bronchospasm, ETT kinked
- **Rebreathing
- Point D
10
Q
- Increased alpha angle on CO2 curve seen with?
- Decreased slope during inspiration phase with widened beta angle seen with?
A
- Airflow obstruction (COPD, bronchospasm, kinked ETT)
- Incompetent expiratory unidirectional valve
11
Q
- The pulse ox utilizes the ___ law.
- It emits two wavelengths of light: oxygenated blood better absorbs near infrared light (___ nm) and deoxygenated blood better absorbs red light (___ nm).
- Looks at ratio of light absorption during peak and trough of waveform. At the peak, ratio of arterial to venous blood is ___.
A
- Beer lambert law
- 940 nm, 660 nm
- increased
12
Q
If the SPO2 is 90 the PaO2 is ___.
If 80 it is ___.
If 70 it is ___.
A
60
50
40
13
Q
The pulse ox is a useful monitor of?
A
Vascular compression
not anemia, bronchial intubation, ventilation
14
Q
Most common method of exhaled gas analysis in the OR today?
A
Infrared absorption
