Test 5 Flashcards
What is the goal of mechanical ventilation?
Reduce WOB by providing adequate alveolar gas exchange with minimal damage to lung tissue (barotrauma) and/or interference with the circulatory system.
Most common conventional neonatal ventilators use ________ modes in order to protect the newborn’s lungs from barotrauma.
pressure-limiting
In pressure-limited modes, a mechanical positive pressure breath will be terminated once a ______ has been reached.
preset peak inspiratory pressure (PIP)
A limit variable that will not allow the delivered breath to result in a pressure greater than the set PIP.
PIP
A positive pressure maintained in the patient’s airway and throughout the closed ventilator circuit during the expiratory phase of ventilation.
Positive End-Expiratory Pressure (PEEP)
A suggested starting point for PIP is between _____.
16 and 20 cm H2O.
The tidal volume achieved in pressure-limited ventilation is variable, depending on what?
Lung compliance and airway resistance.
Patients with poor lung compliance require higher _____ than those with good compliance to achieve the same tidal volume.
PIP levels
If the ventilator is unable to reach the set PIP before the breath is cycled into exhalation, it may be due to things like what?
A leak, such as an endotracheal tube cuff leak or a ventilator circuit leak.
If PIP is reached too soon, limiting the resulting tidal volume, it may be due to what?
An airway obstruction, a kink in the endotracheal tube, bronchospasm, or decreased lung compliance.
Endotracheal tube resistance can be reduced by:
Shortening the tube
In the presence of which of the following scenarios could shorter inspiratory times and faster rates be used without the risk of air trapping?
RDS
Which is the main factor that determines airway resistance?
Airway radius
As volume is extracted from the thorax at its unstressed volume, the ribs:
Recoil outward
What best describes wasted ventilation?
The ratio of physiologic deadspace to tidal volume
Normal lung compliance in a newborn is:
2.5 to 5 ml/cm H2O
It can decrease to as low as 0.5 mL/cm H2O/kg with RDS
The normal airway resistance in a spontaneously breathing neonate is:
20 to 30 cmH2O/L/sec
The maximum pressure exerted against the patient’s airway during inspiration
Peak inspiratory pressure
PEEP is considered a _______, which means at the end of exhalation the airway pressure will return to this level prior to the trigger of the next breath.
baseline variable
Higher levels of PEEP may
lead to ______________.
increased mean airway pressure, resulting increased intrathroacic pressure and the possible reduction of cardiac output.
If PEEP is increased in pressure-limited modes, the resulting tidal volume will be __________________.
a. Increased
b. Reduced
b. Reduced
What type of variable is frequency (rate)?
Trigger variable determined by the cycle time of each breath.
The number of inspirations that occur in 1 minute
The frequency of ventilation or rate
Modern conventional neonatal ventilators have the capacity of providing rates of up to _____.
150 bpm.
___________ is set by the operator and is a cycle variable that will cycle the breath into exhalation once the preset IT is achieved.
Inspiratory time (IT)
The average pressure exerted on the airway and lungs from the beginning of inspiration until the beginning of the next inspiration.
Mean Airway Pressure (MAP)
What is MAP affected by?
PIP, PEEP, IT, and rate.
MAP levels above____________ have been shown to contribute to barotrauma.
12 cm H2O
Minute ventilation is equal to the ________.
tidal volume multiplied by the respiratory rate.
Any gas that does not participate in gas exchange.
Deadspace
Deadspace is divided into two categories:
anatomic deadspace and alveolar deadspace.
The volume of tidal gas that fills the airways at the end of inspiration.
Anatomic deadspace
Anatomic deadspace comprises the airways beginning at the _____.
nose and ending at the terminal bronchioles.
Anatomic deadspace in a neonate is roughly __________ mL/kg.
2 to 2.2 mL/kg
Which type of deadspace is impossible to determine and can vary tremendously from hour to hour in the same patient?
Alveolar deadspace
The total of anatomic and alveolar deadspace is called what?
physiologic deadspace (VD).
The portion of tidal gas actually participating in gas exchange.
Alveolar ventilation
The difference between the baseline pressure, or PEEP (if the baseline is above 0 cm H2O), and the PIP.
Driving pressure
The amount of gas remaining in the lungs at the end of a passive exhalation.
FRC - Functional Residual Capacity
The amount of gas inhaled in a single breath is called the _________.
Tidal volume (VT)
During mechanical ventilation, the tidal volume is the volume of gas that enters the patient’s lungs during which respiratory phase?
Inspiratory phase
The two ventilator parameters that most directly affect tidal volume in pressure control ventilation are _____ and _________.
PIP and PEEP
There are several factors that determine the level of flow through a tube. They are:
1) the difference between the inlet and the outlet pressures, which is the driving
pressure
2) the radius of the tube
3) the length of the tube
4) the viscosity of the gas
FACTORS THAT INCREASE AIRWAY RESISTANCE
- Bronchospasm
- Airway secretions
- Edema of the airway walls
- Inflammation
- Artificial airway
a. Endotracheal tube
b. Tracheostomy tube
The direction of thoracic recoil depends on the ______.
volume in the thorax.
The amount of pressure required to increase the volume in the lungs is directly related to the number of ___.
elastic elements that are present in the lung tissue.
Compliance measured during an active breath is called _____.
Dynamic compliance
When is static compliance measured?
It is measured when there is no airflow through the lung at the end of inhalation through an inspiratory hold maneuver.
What are the determinants to delivered tidal volume?
- PIP
PEEP levels are usually kept between _____ cmH2O
4 and 6
If PEEP is increased in pressure-limited modes, the resulting tidal volume will be reduced. In order to maintain the same minute ventilation in this instance, it is necessary to _______________.
either increase PIP to maintain the same tidal volume or increase respiratory rate to maintain the same minute ventilation.
_________ is the most powerful influence on oxygenation.
Mean Airway Pressure (MAP)
High levels of MAP lead to _______________.
- decreased cardiac output
- pulmonary hypoperfusion
- increased risk of barotrauma
What is the best indicator of balance between adequate ventilation and excessive pressures?
MAP
The delivered tidal volume is directly related to the what?
vertical distance from the baseline pressure to the PIP level.
The portion of the tidal gas that fills unperfused alveoli.
Alveolar deadspace
When physiologic deadspace (VD) is compared to tidal volume (VT), the ratio (VD:VT) reflects the portion of the tidal breath that _________ participating in gas exchange.
is not participating in gas exchange.
Opening pressure and alveolar recruitment can be assessed when crackles are heard in the lungs during _______.
inspiration
How are crackles heard?
As the wet alveoli are opened, the pulling apart of the alveolar walls creates the crackles. Heard on end-inspiration.
In theory, when mechanically ventilating a neonate, the driving pressure must be equal to the ____ to open and ventilate the alveoli.
opening pressure
Clinically, in addition to assisting with oxygenation, PEEP is used to what?
stabilize the alveoli and reduce the surface tension.
The surface tension in the alveoli is reduced as FRC deceases/increases, resulting in less pressure being required to open the alveoli during inspiration.
increases
Alveolar ventilation is also affected by the length of time that the gas is in contact with the alveoli, or _______.
the diffusion time
The diffusion time is controlled by the ______and ___.
inspiratory time and peak flow
Increasing or decreasing peak flow changes what?
the speed at which the gas enters the alveoli.
The flow rate used determines the _____.
wave pattern of the ventilator breath.
True or false: Any change in ventilator parameters will change another parameter to some degree.
True!
The exception to this is the FiO2.
An __________ has the ability to resist deformation when a force is exerted against it, and thus produces a recoil force.
Elastic structure
According to ______, when an elastic substance is stretched, tension develops that is proportional to the degree of deformation that is produced.
Hooke’s law
This relationship between a given change in volume and the pressure difference required to achieve that volume change is called ___________ and directly reflects the ability of the lungs to stretch.
compliance
A plateau pressure is measured during the _________.
0.5 second inspiratory hold.
Which type of compliance only reflects the elastic properties of the lungs?
Static compliance
Compliance measured during an active breath is called ______.
Dynamic compliance
Static compliance equation
VT/(Pplat-PEEP) or VT/Driving pressure
Dynamic compliance equation
VT/(PIP-PEEP)
__________ compliance better reflects the elastic recoil of the lungs
Dynamic
The two main determinants of lung compliance are ______.
alveolar surface forces and elastic elements in the lung tissue.
Does the lung recoil inward or outward?
Inward
When the pressure inside the thorax is the same as outside the thorax, this is referred to
as the _______.
Unstressed volume.
_______ is determined when the inward pull of the lungs is balanced with the outward pull of the thorax and the unstressed volume in the chest is reached.
FRC
High pressure also further decreases cardiac output by _____________.
decreasing venous return to the right heart
The pressure difference between the inlet and the outlet determines the rate of flow, with a greater pressure difference resulting in a greater flow and vice versa.
Poiseuille’s law
When dealing with the airways, the length of the airway and the viscosity of the gas remain relatively constant, so the only factor that changes resistance to airflow is a change
in the _______.
radius of the airway
____ is measured as the ratio between the driving pressure, measured in cmH2O, and the amount of flow in liters per second.
Resistance
The basic definition of airway resistance is the _________________________.
driving pressure needed to move gases through the airways at a constant flow rate.
In the lung, the driving pressure is the difference between _____ and________.
the pressure at the mouth (inlet pressure) and the alveoli (outlet pressure).
There are other factors that may lead to increased airway resistance that are not associated with the normal anatomy of the airway. Neonates have an increased level of_______, which reduces the radius of the airway.
interstitial fluid in the lungs
Turbulent flow is present in a 2.5 mm ETT at flow rates exceeding _____________.
3 Lpm and at flows exceeding 7.5 Lpm in a 3.0 ETT.
Of all the factors that affect resistance in the airway, by far the most powerful influence is a change in the __________.
radius of the airway.
According to Poiseuille’s law, for every decrease in the radius, resistance increases to the______.
fourth power
Driving pressure equation
Vt/Cstat
Airway resistance that exists due to the placement of an endotracheal tube can be reduced by doing what?
Shortening the tube and only allowing 4 cm of the tube extends beyond the lips.
_______ reflect the amount of time required for alveolar and proximal airway pressures to equilibrate.
Time constants
In other words, time constants are the amount of time required for the lungs to inhale or exhale.
What are the two forces that determine the time required for exhalation?
- The elastic recoil of the lung
- Chest wall (compliance) and the opposition to airflow (resistance).
One time constant equals the time required for the alveoli to discharge ___ of the tidal volume.
63%
Three time constants are required before ____ of the tidal volume is emptied.
95%
What is the immediate indication for mechanical ventilation?
Respiratory failure
Mixed respiratory failure is manifested by both ________ and ________.
Hypoxemia and hypercapnia.
What is the end result of hypercapnic respiratory failure?
Hypoxic-ischemic encephalopathy
Define hypoxemic respiratory failure
- PaO2 ≤50 mmHg on a FiO2 of ≥60% (PaO2/FiO2 ratio < 300 observed in acute lung injury) despite the use of continuous positive airway pressure (CPAP)
- decreasing PaO2 (or SpO2)
Frequently, they present with hypocapnia and respiratory alkalemia.
Clinical features of hypoxemic respiratory failure:
- Agitation
- Cyanosis
- Tachycardia
- Bradycardia (late)
- Tachypnea (>70–80 breaths/min in neonates; >50 breaths/min in children).
Classic signs of distress in neonates also include: - Nasal flaring
- Grunting
- Marked thoracic retractions (substernal, sternal, intercostal, supraclavicular, and suprasternal)
The primary dysfunction in RDS is ________________.
abnormal alveolar surface forces resulting from capillary leak and a lack of surfactant.
Approximately ____ of surfactant is phospholipid, with phosphatidylcholine (PC) comprising ____ of the total.
Approximately 90% of surfactant is phospholipid, with phosphatidylcholine (PC) comprising 85% of the total.
Roughly ______ of the PC is dipalmitoyl phosphatidylcholine (DPPC).
60
It is the _________ that allows surfactant to lower surface tension.
dipalmitoyl phosphatidylcholine - DPPC
______ is the predominant neutral lipid in surfactant.
Cholesterol
What are two the primary protocols for the administration of surfactant during the neonatal period?
- Therapeutic administration
- Prophylactic administration
Prophylactic administration of surfactant is indicated for those infants who are _________________.
at a high risk of developing RDS.
Infants born before 32 weeks, those who weigh less than 1300 grams, those with an L/S ratio less than 2:1, or those with an absence of PG in the amniotic fluid.
Therapeutic administration (also called rescue) is not given until the patient _______________.
develops signs of RDS.
Indications: require ventilatory assistance due to an increased work of breathing (grunting, nasal flaring, retractions), increasing oxygen requirements, and having chest x-ray evidence of RDS.
Although SRT may not reverse the lung injury, it has been shown to improve lung volumes by _______________.
stabilizing alveoli and increasing compliance and oxygenation.
Currently, most surfactants fall into two categories which are:
those obtained from mammalian lungs and those that are synthetically produced.
Adverse effects of SRT can include ____________.
bradycardia, oxygen desaturation, and ETT reflux.
What is the dosage/birth weight of EXOSURF?
5 mL/kg
What is the dosage/birth weight of SURVANTA?
4 mL/kg
What is the dosage/birth weight of INFASURF?
3 mL/kg
What is the dosage/birth weight of CUROSURF?
2.5 mL/kg
A technique of ventilation that delivers small tidal volumes at very high respiratory rates with PEEP used for alveolar expansion.
HFV
According to the FDA, HFV is any form of mechanical ventilation that delivers respiratory rates that are greater than ________.
150 per minute.
HFV
______ refers to peak-to-peak pressures or the difference between peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP).
Amplitude
HFV
Oxygenation is primarily controlled by adjusting the _________, whereas carbon dioxide removal is a result of the amplitude pressure.
mean airway pressure
HFV
The major advantage of delivering small tidal volumes is that it can be done at
relatively low pressures, greatly reducing the risk of ________.
barotrauma
The indications for any type of HFV in the neonatal population are primarily linked to what?
respiratory failure that does not respond to conventional methods of mechanical ventilation.
What has been shown to be a safe and effective rescue technique in treating patients who have failed conventional ventilation, in newborns with congenital diaphragmatic hernia, and in neonates with RDS or air leak syndrome?
High-frequency oscillatory ventilation (HFOV)
HFV has been known to cause what?
- gas trapping
- hyperinflation
- obstruction of the airway with secretions
- hypotension
- necrotizing tracheobronchitis.
High-frequency ventilators deliver rates between _________.
150 and 3000 bpm.
HFV
Chest assessment of patients on HFV is difficult. Assessment for adequate ventilation is based on ______ rather than chest rise and fall.
chest wall vibration (wiggle)
HFV
A decrease in chest wall vibration with an increased PaCO2
without a decrease in PaO2 may indicate an_________.
obstruction or malposition of the ETT.
_____________ are observed by a decrease in chest wall vibration, increase in PaCO2and a decrease in PaO2.
Decreased lung compliance and pneumothoraces
The major types of HFV are categorized by the ______ and ________.
frequency of ventilation and the method with which the tidal volume is delivered.
What type of high-frequency ventilator?
Simply conventional ventilatory breaths delivered at rates between 60 and 150 bpm (1 to 2.5 Hz). The delivery of tidal volume during .. occurs via convective air movement, in which tidal volume exceeds dead space.
High-Frequency Positive Pressure Ventilation - HFPPV
What type of high-frequency ventilator?
In this type of HFV a control mechanism, usually a rotating ball with a gas pathway, interrupts a high-pressure gas source in order to deliver rapid rates. Exhalation occurs passively.
High-Frequency Flow Interruption - HFFI
What type of high-frequency ventilator?
Generally operates in the range of 4 to 11 Hz. It delivers a high pressure pulse of gas to the patient airway. This is done through a special adaptor attached to the endotracheal tube, or through a specially designed endotracheal tube that allows the pulsed gas to exit inside the endotracheal tube.
HFJV
What type of high-frequency ventilator?
Utilizes the highest of rates, usually in the range of 8 to 30 Hz. The oscillatory waves that deliver the gas to the lungs are produced by either an electromagnetically driven piston pump or a loudspeaker. These oscillatory waves produce a vibration or shaking motion of the infant’s chest that should be observed to verify adequate amplitude and thus gas delivery.
HFOV
What is the most widely used method of HFV?
HFOV, It does not require a specialized endotracheal tube or conventional
ventilation in tandem with the oscillator.
A unique feature of HFOV is that it produces _____________________.
a positive as well as a negative stroke, which assists both inspiration and exhalation.
The primary indication for heliox therapy is during any clinical situation
where ________________.
airway obstruction prevents or significantly impedes the delivery of gas flow throughout the airways.
The therapeutic result of heliox therapy is ________.
reduction in airway resistance and respiratory muscle work.
Heliox can be delivered in 60:40 to 75:25 blends of He and O2, depending on the patient’s FiO2 needs. However, as the amount of O2 increases in the mixture, above____, the less the benefit in reducing airway resistance.
30%
i-NO is indicated when a _______.
deficiency occurs in the body’s ability to produce its own NO.
What conditions have been shown to respond favorably to i-NO?
- PPHN
- RDS
- MAS
- pneumonia
- sepsis
- congenital diaphragmatic hernia
Which gas is known for its low density and its being inert, it makes it an ideal gas to mix with oxygen to reduce both turbulence in airflow and resistive pressure in the airways?
Helium
Care must be taken in the withdrawal of i-NO. A sudden withdrawal of i-NO may cause a rebound effect, resulting in ______ and _______.
pulmonary hypertension and hypoxemia.
Withdrawal of i-NO should not be considered until the patient shows marked clinical improvement; the patient should be hemodynamically stable on an FiO2 less than 40% with a PEEP of 5 cm H2O or less. If the patient meets these criteria the next recommended step is to increase the FiO2 to 60% to 70% before withdrawal of i-NO, and prepare to support the patient hemodynamically if necessary. i-NO withdrawal has been well tolerated when these guidelines are followed.
READ IT AND WEEP
What measurements determine the inclusion of ECMO?
- Oxygen Index
- P(A-a)O2
ECLS EXCLUSION CRITERIA
- Gestational Age: <35 weeks
- Preexisting Conditions: Intraventricular hemorrhage
- Conventional ventilaton >7 days
ECLS INCLUSION CRITERIA
Include infants with:
1. A-a difference: >620 torr for 6–12 hours
2. Oxygen Index: >40 for 1–6 hours
In the venoarterial route, blood is drawn from the _____ via the _____.
right atrium via the internal jugular vein.
Venoarterial ECLS:
The oxygenated blood is returned to the aortic arch via the __________.
right common carotid artery
Which form of ECLS not only oxygenates the blood, but also supports the cardiac function of the patient by ensuring systemic circulation?
Venoarterial
In the venovenous ECLS route, blood is removed from the right atrium via a catheter inserted in the __________.
right internal jugular vein.
Venovenous ECLS:
The oxygenated blood is returned to the right atrium through a catheter inserted via the ______.
femoral vein
Which ECLS method oxygenates the blood, but does not support cardiac output?
Venovenous
Complications of ECLS are both technical and physiologic. Common physiologic complications of ECLS are those related to _________.
bleeding, secondary to the high level of heparin required for anticoagulation
______, ______ and ________ are all possible hematologic complications caused by the consumption of blood components by the membrane oxygenator
Anemia, leukopenia, and thrombocytopenia
Technical complications that may arise during ECLS include________.
- failure of the pump
- rupture of the tubing
- failure of the membrane
- difficulties with the cannuls
Impairment of renal function and marked fluid retention appear to be unique complications when the which route of ECLS is used?
Venovenous
The concept behind liquid ventilation is to obliterate the air/liquid interface at the alveoli and thus substantially lower surface tension. Mechanical inflation could then occur at pressures low enough to not damage lung tissues.
Read it and weep
What type of liquids are the first substances that have been shown to support respiration while remaining relatively nontoxic to the lungs?
Perfluorochemical (PFC)
PLV with perfluorocarbon liquid occurs by using the liquid to recruit atelectatic lung tissue and reduce surface tension in the alveolar lining. During exhalation the liquid acts as a reservoir of oxygen, preventing alveolar collapse and intrapulmonary shunting. With the next inspiration, tidal volume gas removes carbon dioxide from the liquid and replenishes it with a new supply of dissolved oxygen.
Read it and weep
What has been shown to be compatible with surfactant administration, and may even be superior to surfactant?
Partial Liquid Ventilation
NPV was never accepted as an alternative to PPV, possibly due to the inconvenience created by _____________.
limited access to the infant as well as limited success on the infant with severe IRDS.
What is the the major advantage to the use of NPV?
- Little risk of barotrauma and the complications of invasive positive pressure ventilation.
- Cardiac system is not compromised
Disadvantages of NPV include:
- Poor access to the patient
- Pressure sores at contact points
- Air leaks
Because of the potential risks associated with ELCS, selection is based on strict criteria and only those infants who are at an ________ risk of mortality should be treated with ECLS.
80% or greater
i-NO: Pharmacological effect
Increase in oxygenation tension due to dilation of pulmonary vessels
With hypercapnic respiratory failure, how may the infant present?
- Apneic
- Listless
- Cyanotic
- Bradycardia
- Tachycardia
It is generally accepted that mechanical ventilation is indicated when ______.
one or more reversible problems (ventilation, acidemia, and oxygenation) exist.
Diagnoses in which the decision is made to withhold life support include:
- birth weight less than 800 g
- intracranial hemorrhage
- periventricular leukomalacia
- severe necrotizing enterocolitis
- hypoxic-ischemic encephalopathy
- intractable respiratory failure
- major congenital anomalies
- chromosomal abnormalities.
A _______ is described as the combination of control, phase, and conditional variables.
mode of ventilation
The ______ variable is that which does not change when compliance or resistance changes.
control
In_______ , if compliance or resistance changes in the lung, volume does not change; pressure changes.
volume-controlled ventilation
In _________, when compliance or resistance changes, pressure remains constant.
pressure-controlled ventilation
A _____ variable refers to how a breath is initiated.
trigger
The patient’s inspiratory effort may be _______ triggered.
time, pressure, flow, or volume
The _____ variable is that which is reached before the end of inspiration and may include time, pressure, volume, or flow.
limit
The ______ variable is that which ends inspiration.
cycle
The _____ variable defines expiration, which is usually measured only by pressure.
baseline
________ describe the conditions that must exist for initiating a sigh breath, or a mandatory breath during synchronized intermittent mandatory ventilation (SIMV).
Conditional variables describe the conditions that must exist for initiating a sigh breath, or a mandatory breath during synchronized intermittent mandatory ventilation (SIMV).
__________ includes those modes indicated for patients who are capable of maintaining all or part of their minute ventilation spontaneously.
Partial ventilatory support
What are some examples of partial ventilatory support modes?
- CPAP
- PSV
- IMV at low rates
- SIMV at low rates
What are the primary partial support modes used for neonates?
- CPAP
- IMV
The application of a continuous positive distending pressure to the airways while the patient is spontaneously breathing.
CPAP
How is CPAP accomplished?
- increasing the functional residual capacity (FRC),
- increasing compliance
- decreasing total airway resistance
- decreasing respiratory rate
In RDS, one of the last organs to mature in utero is the ____.
respiratory system
CPAP is administered to a child through the endotracheal tube. A mask is not advised, because the child may _______.
aspirate air, leading to gastric distention, vomiting, and aspiration of gastric contents
What are the five indications for CPAP?
- Decreased FRC
- Airway collapse
- Weaning from MV
- Abnormal physical examination
- Abnormal arterial blood gases
One of the primary causes of airway collapse is ________.
tracheobronchial malacia
Initial CPAP pressures should start at between ______ cmH2O.
4-5
Increased in 2 increments as needed.
Up to a CPAP of 10.
When CPAP is considered successful?
FiO is stabilized at ≤60% with a PaO ≥50 mmHg or SO >90%, a decreased work of breathing, decreased retractions, nasal flaring, or grunting, improved aeration on the chest radiograph, and subjectively improved patient comfort.
When CPAP fails, what is initiated next?
IMV
The principal hazard of CPAP therapy is that associated with ________.
high pressures (barotrauma)
CPAP breaths are classified as ________ controlled, _________ triggered, _________ limited, and _________ cycled.
pressure controlled, pressure triggered, pressure limited, and pressure cycled
What happens when CPAP is initiated using excessive pressures?
- Diminished blood flow
- Reduced CO
CPAP also increases ICP
CPAP contraindications:
in the presence of upper airway abnormalities such as:
- choanal atresia
- cleft palate
- tracheoesophageal fistula
- untreated air leaks (pneumos)
- congenital diaphragmatic hernia
CPAP
As soon as the patient begins to show signs of clinical improvement, the FiO2 is decreased in ____ decrements until the FiO2 reaches 40% to 60%.
5%
A mode of ventilation that supplements spontaneous patient inspiratory effort with a clinician-selected pressure level.
PSV
The pressure difference between EPAP and IPAP determines ___.
tidal volume
BiPAP is the same as PSV with _____.
PEEP
The mode ode of ventilation that provides mandatory breaths (a clinician-specified rate), which allows the patient to breathe spontaneously during the periods between mandatory breaths.
Intermittent mandatory ventilation (IMV)
For IMV to be referred to as a mode of PVS, the mandatory rate must be ___________. to allow for effective spontaneous ventilation.
low (<30 breaths/min in the neonate)
IMV Indication:
IMV is indicated when CPAP proves ineffective, or in any instance of hypercapnic ventilatory failure is apparent.
IMV
The mandatory breaths are ________controlled, _________ triggered, _______ limited, and ________cycled.
pressure controlled, time triggered, pressure limited, and time cycled.
Just know.
IMV increases MAP more than CPAP does
Okay
IMV is only contraindicated when it is ______.
not necessary.
What are the SIMV advantages over IMV?
- Prevents breath stacking
- Easier monitoring
Modes of _________ provide all of the required minute ventilation for a particular patient.
full ventilatory support
Full Ventilatory Support Examples
- SIMV
- CMV
_______ is indicated when all of the minute ventilation must be supplied by mandatory breaths.
Continuous mandatory ventilation (CMV)
Time-triggered CMV is applied to patients who have been ______.
paralyzed traumatically or pharmacologically.
PCV is indicated for patients (children and adults) with acute respiratory distress syndrome (ARDS) that results in a plateau pressure ____ cm H2O or a peak pressure _____ cm H2O while on volume ventilation.
PCV is indicated for patients (children and adults) with acute respiratory distress syndrome (ARDS) that results in a plateau pressure ≥35 cm H2O or a peak pressure ≥40 cm H2O while on volume ventilation.
IRV is indicated for those patients who _________.
fail to oxygenate despite high FiO2 and PEEP.
Patient management becomes more difficult in IRV because what?
Mean airway pressure rises precipitously
Which mode does this describe?
The patient is placed on a physiologic level of CPAP above baseline to restore his or her FRC. Ventilation occurs when the exhalation valve opens, allowing the pressure to fall to ambient, resulting in a patient exhalation. CPAP is restored the moment exhalation ceases.
APRV
If the patient does not reach the desired volume, the machine provides assisted breaths, allowing the targeted volume to be achieved. This mode is used mainly during weaning to prevent patient exhaustion during spontaneous breathing.
Mandatory Minute Ventilation and Augmented Minute Ventilation
Once it is determined that the patient is in respiratory failure, the _______ is often the first setting made on the ventilator.
mode
In combined respiratory failure, what mode is chosen?
IMV or SIMV with CPAP/ PEEP or CMV with PEEP is chosen to support both ventilation and oxygenation.
The _______ is limited by a pop-off valve or by limiting the pressure applied to the expiratory valve and allowing excess pressure to vent through the expiratory side of the ventilator circuit.
inspiratory pressure
To set the PIP for a neonate, PIP is usually maintained at the pressure used during resuscitation, usually at _____ cm H2O.
15-20
In pressure triggering, the sensitivity is set to ____.
−1 to −2 cm H2O.
In flow triggering the sensitivity is set to _______.
0.15 to 1 L/minute.
In volume triggering, the sensitivity is set to up what?
to 3.0 mL.
PEEP range
3-5 cmH2O
Neontal PaO2 range
50-80 mmHg
Inspiratory flow range on ventilator
6 to 8 L/min
A flow of ______ should deliver the set tidal volume within the recommended 1.0 to 1.5 second inspiratory time.
25 to 30 L/minute
Once a patient is placed on a mechanical ventilator, one goal should be to ________________________.
reduce the work of breathing.
What control begins timing the breath at the instant the expiratory time control signals the closure of the expiration valve?
Inspiratory time
In RDS, do infants require a longer inspiratory or expiratory time?
Inspiratory
Calculate i-Time
Vt/flow
Desired Vt for preterm infants
4-6 mL/kg
Desired Vt for term infants
6-8 mL/kg
I:E ratio
1:1.5 – 1:2
Inspiratory time range
Low-birth-weight infants 0.25–0.5 sec
Term infants 0.5–0.6 sec
FiO2 range
Set to keep patient pink, or SpO2 of 90–92%
INITIAL VENTILATORY PARAMETERS
Rate
30-40 breaths/min
What is the primary method of ventilating neonates?
Pressure-limited, time-cycled ventilation
The easiest method to achieve volume-targeted ventilation with a pressure controlled ventilator is to change the ___________ until the desired range of tidal or minute volume is achieved.
peak pressure limit
Tidal volume may be decreased by decreasing the…
the inspiratory time or flow rate
The tidal volume in pressure-controlled ventilation is determined by the difference in pressure ________________________. (4)
between the PIP and PEEP (the ΔP), resistance, and compliance.
PEEP is the most important parameter determining mean airway pressure, because the relationship between mean airway pressure and end-expiratory pressure is 1:1.
Know this
What settings alter PaCO2?
- Rate
- PIP
- Flow
- Inspiratory time
In RDS accompanied by high peak or plateau pressures, it may be desirable to allow the PaCO2 to rise above 50 mmHg, as long as the ____________________. This technique, permissive hypercapnia, allows a reduction in tidal volume, and assists in avoiding baro/volutrauma.
pH does not decrease below 7.25.
MAP is increased by increasing what parameters?
- PEEP
- PIP
- set rate
- inspiratory time
- decreasing expiratory time (increasing the I:E ratio).
Hazards of high oxygen concentrations
- Oxygen toxicity
- Possible absorption atelectasis
- Hypoventilation from excessive FRC
- ROP
- BPD
- Reduced CO
General hazards of mechanical ventilation include infection, hypoxic-ischemic injuries, intracranial hemorrhage in the neonate, gastric distention, and complications of endotracheal intubation.
When making the decision whether to wean and extubate, two factors must be considered:
1) the ability of the patient to spontaneously maintain adequate gas exchange
2) the ability of the patient to maintain the airway and clear secretions
Once the FiO2 is ≤0.4, ______ is decreased in 1 to 2 cm H2O increments to 3 to 4 cmH2O before considering extubation.
PEEP
A negative reaction to a weaned parameter that requires not only a reinstitution of the parameter but often reinstitution to a level higher than was set before the weaning.
Rebound effect
Clinical indications of failure to wean
- Tachycardia
- Bradycardia
- Pallor
- Retractions
- Hypercapnia
- Cyanosis
Settings that indicate patient can be extubated
PIP: 15-18 cmH20
PEEP: 3-5 cmH20
Rate: Less than 10
FiO2: 30-40%
Weaning then begins when the patient has met what criteria?
1) The disease process is stabilized and past the acute phase
2) the cardiovascular system is stable
3) gas exchange is stable without the need for high pressures or FiO2
4) the patient is alert with minimal sedation
How does capillary blood arterialize?
Warm the foot (heel)
