Pilbeams Chapter 5 Flashcards
What disorders are managed by Non-invasive PPV?
Chronic RF
Chest Wall deformities
Neuromuscular disorders
Central alveolar hypoventilation
COPD
Cystic Fibrosis
Acute RF
Pneumonia
What are some ADVANTAGES of Non-invasive PPV in ARF?
-Avoids complications associated with artificial airways.
-Provides flexibility in initiating and removing MV.
-Reduces req. for heavy sedation.
-Preserves airway defense, speech, swallowing mechanisms.
-Reduces the need for invasive monitoring.
What are some DISADVANTAGES of Non-invasive PPV in ARF?
-Gastric distention, skin pressure lesions, facial pain, dry nose, eye irritation, discomfort, claustrophobia, poor sleep, mask leaks
What is considered full vent support?
-When the PaC02 is below 45 or what is normal for the patient.
-When the ventilator rate is above 8 br/min
-VT is adequate for the patient.
-Full vent support is provided when there is a pre-set volume or pressure when a breath is delivered.
What is considered partial vent support?
-Machine breaths are lower than 6 br/min and the patient participates in the WOB.
Examples: PSV, MMV, IMV, PAV
-
The breath delivery and mode is determined by the following factors:
-Type of breath (Mandatory, Spontaneous, Assisted)
-Targeted control variable (Volume or Pressure)
-Timing of breath delivery (CMV, IMV, or CSV)
Mandatory breaths
When the ventilator controls the timing, VT or inspiratory pressure.
Spontaneous breaths
The patient controls the timing and the VT. The volume or pressure or both is not set by the clinician but based on demand and the patient’s lung characteristics.
Has characteristics of both mandatory and spontaneous breaths.
Assisted breaths
What is the goal of volume controlled ventilation?
To maintain a certain level PaCO2
What is the main DISADVANTAGE of using volume-controlled ventilation?
If the lung condition worsens, the peak pressures may rise leading to alveolar distention.
What happens to the peak pressures as the lung becomes less compliant (stiff)?
The peak pressures rise. When the lungs become more compliant, the peak pressures decline.
A decelerating flow pattern is seen in what mode?
Pressure -Controlled
What are the 3 types of breath delivery timing available on ICU ventilators?
- CMV
- IMV
- CSV
With this mode, all breaths are mandatory, and can be volume targeted or pressure targeted. Breaths can be time or patient triggered.
CMV
When the breaths are time triggered in CMV, this is called what?
Controlled Ventilation
When the breaths are patient triggered in CMV, this is called what?
Assisted Ventilation
What factors affect volume delivery during pressure-controlled ventilation?
-Pressure setting
-Pressure Gradient
-Patient’s lung characteristics
-Inspiratory time
-Patient effort
This type of ventilation is appropriate only when a patient cannot make an effort to breathe.
Controlled Ventilation (Time triggered)
What type of patient is Controlled ventilation (Time triggered) most appropriate for?
-Obtunded because of drugs
-Cerebral malfunction
Spinal cord or phrenic nerve injury
-Motor nerve paralysis
What occurs during PC-inverse ratio ventilation?
The inspiratory time is set longer than the expiratory time to provide better oxygenation to some patients by increasing the mean airway pressure.
Sometimes the goal is to prevent full exhalation and auto-PEEP.
PC-IRV is generally used for what patients?
Patients with very stiff lungs.
Patient is able to breathe spontaneously between mandatory breaths at any desired baseline pressure without receiving a mandatory breath.
IMV
(A disadvantage to this mode is the lack of coordination between the mandatory and spontaneous breaths which may cause breath stacking.)
What are the 3 basic means of providing support for continuous spontaneous ventilation (CSV)?
- Spontaneous breathing (T-piece)
- CPAP
- PSV
The patient is still intubated but is not receiving MV. The ventilator is used to monitor the patient’s breathing.
An SBT trial is performed on this mode for about 15-30 minutes while vitals, appearance are measured.
A patient who can tolerate this procedure can typically tolerate longer periods of spontaneous breathing and is probably ready to be weaned.
Spontaneous Breathing (T-piece)
(Weaning method)
This may be useful in improving oxygenation in patients with refractory hypoxemia and a low FRC.
(Weaning method)
CPAP
The ventilator provides a constant pressure during inspiration once it senses that the patient has made an inspiratory effort.
PSV
(Weaning method)
The operator sets 2 pressure levels, inspiratory and expiratory, a full-face mask is typically used.
BIPAP
A dual control mode that provides pressure-limited ventilation with volume delivery targeted with every breath.
Also may be called “VAPS”
Pressure Augmentation (to make bigger by adding to it)
-Pressure is applied to the airway until a specific volume is achieved.
-If the volume is achieved before the inspiratory gas flow drops to the preset value, the vent cycles into expiration.
-Cycling occurs then the measured flow drops to 25% to 30% of the patient’s PIP flow
-P-aug
Pressure Augmentation (VAPS)
-If the volume is not achieved before the flow drops to the set level, the ventilator maintains the flow at the set value until the volume is delivered.
-Pressure Aug. targets a minimum volume, but the breath is not limited to that volume.
-Patients can receive more than the set volume if there is a high flow demand.
-This mode measures the VT delivered and compares it with the targeted VT which is set by the operator.
-If the volume delivered is less than the set VT then the ventilator increases pressure delivery over the next several breaths until the set and target volume are about equal.
PRVC
This mode is very similar to PRVC, it is basically PS with a targeted volume. There is no back-up rate but there is a back-up mode in the event the patient becomes apneic.
VSV
This mode has been used primarily for weaning patients. It allows the operator to set a mandatory minute ventilation based on 70% to 90% of the patient’s current Minute ventilation.
- The vent provides additional support if the mve is not reached.
-The vent reduces its level of support if the mve is achieved
MMV
The operator sets a TARGETED minute ventilation based on the patient’s ideal body weight and VD volume.
ASV
This mode is most similar to BIPAP. It provides high and low airway pressure levels and allows spontaneous breathing at both levels when spontaneous effort is present.
-The terms P-high and P-low indicate the level of pressure administration during APRV.
The terms T-high and T-low indicates the time spent in high and low airway pressures.
APRV
The pressure, volume and flow delivery are proportional to the patient’s spontaneous effort.
As the patient’s inspiratory effort increases, the flow from the ventilator increases proportionally.
Proportional Assist Ventilation (PAV)
