Test Bank for Pilbeams Mechanical Ventilation 7th Edition by Cairo
_____ _________ change as a result of gas flow into and out of the airways caused by a change in
pressure gradient between the airway opening and alveoli. - ANSlung volumes
1 atm= ______ mm Hg= ______ cm H2O - ANS760mm Hg, 1034cm H2O
1 mm Hg= _______ cm H2O? - ANS1.36cm H2O
3 types of high-frequency ventilation (HFV):
1. HFPPV- high freq positive pressure ventilation
2. HFJV- high freq jet ventilation
3. HFOV- high freq oscillatory ventilation - ANS1. HFPPV- resp rates 60-100bpm
2. HFJV- resp rates 100 and 400-600bpm
3. HFOV- resp rates up to 4000bpm
a disadvantage of volume control mode: - ANSthe patient can have asynchrony with with the ventilator.
the main disadvantage of volume control becomes evident when the lung characteristics worsen.
accessory muscles of inspiration: - ANSscalene, sternocleidomastoid, pectoralis, trapezius
acute respiratory failure may be defined as the inability to maintain pao2, co2, and ph at acceptable
levels.
what paco2 and ph indicate ARF? - ANSco2 greater than 50 and rising, and ph 7.25 and lower
advantages of pressure-controlled mode: - ANSreduces the risk of over distention by setting a max
pressure, the ventilator delivers a decelerating flow pattern during pcv, & PCV can be used with ARDS
patients that have stiff lungs.
Airway opening pressure (Pawo) is most often called mouth pressure (Pm) or airway pressure (Paw).
Other terms that are often used to describe airway opening pressure include: - ANSupper airway
pressure, mask pressure, and proximal airway pressure.
(unless pressure is applied at the airway opening, Pawo is zero or atmospheric pressure)
at what point does bulk gas flow not occur because the pressures across the conductive airways are
equal (i.e. there is no pressure gradient)? - ANSthere is no pressure gradient when the pressure at the
airway opening and the pressure at the alveoli are the same, as occurs at the end of expiration
baseline variable: the expiratory phase - ANSthe pressure level from which a ventilator breath begins is
called the baseline pressure. baseline pressure can be zero (atmospheric), which is also called zero end
expiratory pressure, or it can be positive if the baseline pressure is above zero (peep)
BIPAP: - ANSthis form of ventilation is patient triggered, pressure targeted, and flow or time cycled.
Compliance (C) & Elastance (e): - ANSC=the relative ease with which the structure distends;
e= the tendency of a structure to return to its original form after being stretched or acted on by an outside
force.
Compliance formula: - ANSchange in volume/change in pressure
during a quiet expiration- - ANSrelaxation of the inspiratory muscles cause a decrease in thoracic volume
(diaphragm & external intercostals return to their resting state) and an increase in alveolar pressure.
,Test Bank for Pilbeams Mechanical Ventilation 7th Edition by Cairo
during mechanical ventilation, proximal airway pressure is not typically measured at the airway opening
because of accumulation of secretions and technical errors can alter sensor measurements. Current-
generation ICU mechanical ventilators measure airway pressure (Paw) using a sensor positioned
__________ to the expiratory valve, which is closed during _______. - ANSsensor is positioned
PROXIMAL to the expiratory valve, which is closed during inspiration.
during spontaneous inspiration- - ANScontraction of the inspiratory muscles cause enlargement of the
thorax resulting in a decrease (more negative) in intrapleural and alveolar pressure.
Elastic force vs. Frictional force: - ANSElastic forces arise from the elastic properties of the lungs and
chest wall; Frictional forces are the result of the resistance of the tissues and organs as they become
displayed during breathing and the resistance to gas flow through the airways.
elevation of paco2 leads to an increase in cerebral blood flow as a result of dilation of cerebral blood
vessels. Severe hypercapnia, if left untreated, eventually leads to- - ANSco2 narcosis, cerebral
depression, coma, and death
for patients receiving mechanical ventilation, compliance measurement are made during static or no-flow
conditions(e.g. this is the airway pressure measured at the end of inspiration; it is designated as the
pplat). Thus these compliance measurements are referred to as: - ANSstatic compliance or static
effective compliance
(Cs= Vt/(pplat-eep))
(eep is end expiratory pressure, which some clinicians call baseline pressure. when a patient is receiving
peep, it is the eep value used in this calculation with static compliance)
FULL ventilatory support is provided when ventilator rates are high (______ breaths/min) and tidal volume
is adequate for the patient.
PARTIAL ventilatory support is any degree of mechanical ventilation in which set machine rates are lower
than _____ breaths/min and the patient participates in the WOB to help maintain effective ventilation. -
ANSFULL= 8 breaths/min; PARTIAL= <6 breaths/min
hypercapnic respiratory failure: - ANSoccurs when a person cannot achieve adequate ventilation to
maintain a normal paco2.
(CNS disorders, Neuromuscular disorders, disorders that increase WOB)
hypoxemic respiratory failure: - ANSacute life-threatening or vital organ threatening tissue hypoxia.
Hypoxemic respiratory failure can be treated with supplemental o2 or in combination with peep or cpap.
(V/Q mismatch, diffusion defects, right-to-left shunting, hypoventilation, aging, inadequate inspired
oxygen)
ideally, pip should be ____ & pplat should be _____ - ANSpip <40 & pplat <30
intrapleural pressure (Ppl): - ANSpressure in the potential space between the visceral and partial pleura.
Ppl is normally about -5cm h20 at the end of expiration and about -10cm h20 at the end of inspiration.
Mandatory breaths: - ANSthe ventilator determines the start time for breaths (time triggered) or the tidal
volume (volume cycled)
maximum safety pressure: - ANStypically set by the operator to a value of 10cm h2o above the average
PIP. when max pressure is reached, pressure or volume is decreased for safety.
measurement of the frictional forces that must be overcome during breathing is referred to as: -
ANSresistance
,Test Bank for Pilbeams Mechanical Ventilation 7th Edition by Cairo
most commonly used patient triggers: - ANSpressure and flow
Negative pressure ventilation (NPV):
(neg pressure=pressure less than atmospheric) - ANSwith NPV, as the intrapleural space becomes
negative, the space inside the alveoli becomes increasingly negative in relation to the Pawo. This
pressure gradient results in the movement of air into the lungs. NPV resemble normal lung mechanics.
expiration occurs when the negative pressure around the chest wall is removed. the normal elastic recoil
of the lungs and chest wall cause air to flow out of the lungs.
NIV can reduce the need for intubation in ___ - ____ % of patients. - ANS60-70%
PEEP: - ANSwhen peep is set, the ventilator prevents the patient from exhaling to zero (atmospheric).
(PEEP INCREASES FRC!!!!!!!!!!!!)
(INTRINSIC peep usually occurs when the patient does not have enough time to exhale completely
before the ventilator delivers another breath)
Phases of a breath & phase variables: - ANS-trigger variable: begins inspiration.
-limit variable: limits the value of pressure, volumes, flow, or time during inspiration.
-cycle variable: ends inspiration.
-baseline variable: establishes the baseline during expiration before inspiration is triggered.
Physiological objectives of mechanical ventilation: - ANS1. support or manipulate pulmonary gas
exhange:
alveolar ventilation, and alveolar oxygenation.
2. increase lung volume: prevent or treat atelectasis with adequate end-inspiration lung inflation, & restore
and maintain FRC.
3. reduce the work of breathing
plateau pressure (pplat) is taken during: - ANSinspiratory pause
(elevated pplat can be associated with ards)
(pplat can be used interchangeably with alveolar pressure Palv and intrapulmonary pressure)
Positive pressure ventilation (PPV):
occurs when a mechanical ventilator is used to deliver air into the patients lungs by way of an
endotracheal tube or positive pressure mask. - ANSat the end of inspiration, the ventilator stops
delivering positive pressure. mouth pressure returns to ambient pressure (zero or atmospheric). alveolar
pressure is still positive, which creates a gradient between the alveolus and the mouth, and air flows out
of the lungs.
Ppl can be difficult to measure, so a related measurement is used, which is the esophageal pressure
(Pes), which is obtained by- - ANSplacing a balloon in the esophagus; changes in the balloon pressure
are used to estimate pressure and pressure changes in the pleural space.
pressure limiting: - ANSwhen the ventilator reaches the high-pressure limit, excess pressure is vented
through a spring loaded pressure release, or pop off valve.
pressure-controlled breathing: - ANSpressure waveform remains the same; volume and flow waveforms
will vary with changes in lung characteristics.
resistance formula: - ANSRaw=(PIP-Pplat)/flow
or, could see both ways-
(Raw=Pta/flow)
-Pta=pip-pplat
respiration: - ANSexchange of o2 and co2 between an organism and its environment
, Test Bank for Pilbeams Mechanical Ventilation 7th Edition by Cairo
Spontaneous breaths: - ANSbreaths are started by the patient (patient triggered), and tidal volume
delivery is determined by the patient (patient cycled)
spontaneous ventilation: - ANSmovement of air into and out of the lungs
the highest pressure recorded at the end of inspiration is referred to as: - ANSpeak pressure (Ppeak),
also called peak airway pressure or peak inspiratory pressure (PIP)
The steps to take when assessing someone in respiratory distress: - ANSfirst, determine the patients
level of consciousness. (asleep or awake) second, assess the appearance and texture of the skin. (nail
beds, cyanotic, sweating) third, evaluate the patients vital signs.
The ventilator typically measures variables in one of three places: - ANS1. the upper, or proximal airway,
where the patient is connected to the ventilator.
2. internally, near the point where the main circuit lines connect to the ventilator.
3. near the exhalation valve
three types of mechanical ventilation: - ANSnegative pressure ventilation (NPV), positive pressure
ventilation (PPV), and high-frequency ventilation (HFV)
Time constants (compliance x resistance) is a measure of how long the respiratory system takes to
passively exhale (deflate) or inhale (inflate): time constants for 1sec-5secs= - ANS1=63.2%
2=86.5%
3=95.0%
4=98.2%
5=100%
time-controlled breathing: - ANSHFJV & HFOV control inspiratory and expiratory times and therefore are
examples of mechanical ventilators that can be classified as time-controlled vents.
two components of respiration: Internal & External - ANS1. Internal: exchange of oxygen and carbon
dioxide between systemic capillaries & the cells of the body.
2. External: diffusion of oxygen and carbon dioxide between the alveoli and pulmonary capillaries
two forms of acute respiratory failure: - ANShypoxemic respiratory failure & hypercapnic respiratory failure
Untreated hypoxemia, hypercapnia, and acidosis can lead to: - ANScardiac dysrhythmias, ventricular
fibrillation, & cardiac arrest
volume-controlled breathing: - ANSvolume and flow waveforms remain unchanged; pressure waveforms
vary with changes in lung characteristics.
what must exist for air to flow through the airway? - ANSpressure gradient (i.e. air at one end of the tube
must be higher than the other end)
what type of tx would be beneficial for a patient with post-op atelectasis or obstructive sleep apnea
(OSA)? - ANSCPAP therapy
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