APEX: Monitoring I Respiratory Flashcards
CO2 Waveform consistent with obstruction can show
Elevated peak with normal plateau pressure
Conditions associated with elevated peak pressure and normal plateau pressure : ETT
Kinked ETT
Conditions associated with elevated peak and normal plateau pressure : lungs and other
Bronchospasm
Aspiration of foreign body
What is elevated peak pressure and normal plateau pressure indicates?
Reduction in dynamic compliance caused by increased airway resistance.
Assessment of Pulmonary Resistance and compliance: Resistance formula
Resistance = P(airway) - P (alveolar) / Gas flow rate
Defined as the force that acts opposite to the relative motion of an object?
Resistance
What is the definition of compliance?
Change in Volume/ change in pressure
Change in volume for a given changes in pressusre
Compliance
What does compliance measure?
The elastic properties of the lungs and chest wall
What is compliance influenced by? DAMAP
Degree of lung inflation Alveolar surface tension Muscle tone Amount of interstitial lung water Pulmonary fibrosis
What is dynamic compliance?
The compliance of the lungs /chest wall DURING air movement
Dynamic compliance is the pressure
required to inflate the lung to a given volume is a
Static means
Not moving
Static compliance measures
Lung compliance where there is NO AIRFLOW
Static compliance is the pressure
required to keep the lung inflated to a given volume
Static compliance is the function
of the tendency of the lung/chest to collapse. Since there is no airflow during this measurement there is no resistance to overcome
Dynamic compliance is a function of
Function of AIRWAY RESISTANCE and the TENDENCY OF THE LUNG/CHEST WALL to COLLAPSE
The significance of peak inspiratory pressure and plateau pressure
The peak inspiratory and plateau pressure provide key insight to a patient’s airway resistance and LUNG-THORACIC COMPLIANCE
Peak inspiratory Pressure (PIP)
Is the maximum pressure in the patient’s airway during inspiration
What is PIP affected by?
Because air flow is flowing into the airway during inspiration, PIP is affected by airway resistance and lung-thoracic compliance
Dynamic compliance FORMULA
Tidal volume / Peak pressure- PEEP
What is plateau pressure?
the pressure in the small airways and alveoli after the target TV is delivered.
Plateau pressure is the pressure in the small airways and alveoli after the target TV is delivered. Does airway resistance affect plateau pressure? why/why not?
Since there is no airflow at this time, airway resistance does not affect plateau pressure.
Plateau pressure reflects the
elastic recoil of the lungs and thorax during the inspiration pause (no gas i s moving in or out) of the lungs
What is BAROTRAUMA risk is high ?
Risk increases when plateau pressure exceeds 35cm/H2O
What are complications of ELEVATED plateau pressure?
Ventilator-associated lung injury
Pneumothorax
Pneumomediastinum
SC emphysema
IF Barotrauma exists, you should aim to
Reduce plateau pressure by reducing TV, inspiratory flow and PEEP. Sedation is helpful
Static compliance formula
Tidal volume / Plateau pressure - PEEP
In the adult, the normal static compliance is
35-100 ml/cm H2O
In the Child, the normal static compliance is
> 15cm /cm H2O
If PIP is increase and PP increase then: Total complaince has ________or TV has _______
Total compliance has decreased
TV has increased
If PIP is increased and no changed in PP then: Total compliance has________ or TV has _______
Resistance has increase OR Inspiratory flow rate has increased.
Compliance with : Endobronchial intubation?
Decreased
Compliance with : Pulmonary edema
Decreased
Compliance with : Pleural effusion
Decreased
Compliance with : Tension pneumothorax
Decreased
Compliance with : Atelectasis
Decreased
Compliance with : Chest wall edema
Decreased
Compliance with : Abdominal insufflation
Decreased
Compliance with : Ascites
Decreased
Compliance with : Trendelenburg position
Decreased
Compliance with : Inadequate muscle relaxation
Decreased
Increase resistance in airway with
Bronchial secretion
Compression of the airway
ETT cuff HERNIATION
FB aspiration
Phase I (A-B) represents
Exhalation of anatomic dead space (flat before phase II)
Phase II (B-C) represents
Exhalation of anatomic dead space+ ALVEOLAR GAS.
Upstroke is phase
II
Phase III (C-D) represents
exhalation of alveolar gas.
Plateau phase is
III
Phase IV represents
Inspiration of fresh gas that DOES NOT CONTAIN CO2
Illustrated by return of waveform to baseline
Phase IV
Capnography measures
ETCO2 concentration over time.
Capnography measures 3 main things?
Assessment of metabolism
Circulation
Ventilation
CO2 concentration gradient
From the tissues to the breathing circut
What is the final product of aerobic metabolism?
Carbon dioxide
CO2 diffuses airway then from the tissues on, what happen?
from the tissue and enters the venous circulation, From here, the CO determines the rate of transfer towards the lungs. In the lungs, CO2 follows a concentration gradient as it diffuses across the alveolar capillary membrane. Once the CO2 in the alveolus, ventilation is the process by which CO2 is removed from the body
What point in the CO2 waverform is ETCO2 measure?
Point D
Normal ETCO2
35-40 mmHg
The alpha angle is
Airway obstruction reading
Where is the alpha angle measure?
Point C
Normal alpha angle is
100-110 degreers
An increase alpha angle means
EXPIRATORY AIRFLOW OBSTRUCTION such as COPD, bronchospasm or a KINKED ETT TUBE.
Alpha angle is between
the first expiration upstroke and the plateau line
Beta angle is
REBREATHING reading
The beta angle is measure at what point
point D
When the patient inspires, the capnography should immediately
return to zero because fresh gas flow does not contain CO2
The beta angle is increased indicating
Rebreathing
Causes of Rebreathing
Faulty unidirectional valves
Exhausted CO2 absorbent
If Expiratory vale is faulty you will notice 2 things about the waveform
Beta angle become WIDER DURING INSPIRATORY
Baseline does not return to zero
Middle of case expiratory valve malfunction
Increased the FGF to finish case
after, took valve assembly and flipped the disc over
2 Methods of CO2 analysis
Mainstream (in line)
Sidestream (diverting )
In what CO2 analysis methods is the device attached to the ETT
Mainstream (in line)
What CO2 analysis method has a faster response time,
Mainstream , does not require a water trap or pumping mechanism
Benefits mainstream (in line) CO2 analysis
Because it’s attached to the ETT , it does not increase apparatus dead space as well as adds extra weight
Sidestream (diverting) CO2 analysis location
Located outside of the airway
Sidestream uses what kind of mechanism?
A pumping mechanism continuously aspirate the gas sample from the breathing circuit, and for this reason, the response time is slower.
CO2 analysis method with a water trap
Sidestream ; to prevent contamination of the device.
Identify caused of the abnormal waveform if there is a PROLONGED UPSTROKE
Airflow obstruction
Identify caused of the abnormal waveform if there is a INCREASED ALPHA ANGLE
Airflow obstruction
COPD
Bronchospasm
Kinked ETT
Identify caused of the abnormal waveform if there is a CARDIAC OSCILLATION
Heart beating against the lungs
CARDIAC OSCILLATION more common in ? why?
In children, close proximity of heart to the lungs
Identify caused of the abnormal waveform if there is a CURARE CLEFT
Spontaneous breaths during mechanical ventilation
Identify caused of the abnormal waveform if there is a CURARE CLEFT, If presents during spontaneous ventilation , suggests
INADEQUATE MUSCLE RELAXANT (lack of synchronizaiton between intercostal muscles and diaphragm)
Low ETCO2 indicates
Hyperventilation
Decrease CO2 production
Increased alveolar dead space
BP and CO2
Hypotension leads to CO2 production
Elevated ETCO2 with normal plateau?
Make sure you look at the baseline and that it returns to zero. Its not rebreathing. Occurs with increased production of CO2 or DECREASED ALVEOLAR VENTILATION
Baseline not returning to zero is
rebreathing