Effects of PPV Flashcards
PPV has cardiac considerations include
The amount of PPV we use
The patients lung condition
What does PPV do to MAP
Increases
What does PPV do to CMO
Decreases
Why does PPV decrease CMO?
The impedance of Venous Return
How does PEEP affect MAP?
Increases
How does PPV affect Pulmonary Vascular Resistance?
Increases
High volumes or PEEP does what to alveoli and pulmonary vessels?
Over distend alveoli
Squeeze pulmonary vessels
What is PVR most increased by?
Mean Airway Pressure (MAP)
T/F Pulmonary vascular resistance is increased by PIP?
False
How does PVR affect Right Ventricular Afterload
Increases
Normal people can over come PVR how?
Increasing Right Ventricular Contractions
People with abnormal hearts can not compensate from PVR and then what happens?
Right Ventricular Stroke Volume drops
Dilation of right ventricle can cause what to happen?
Force the intraventracular septum to shift left
What PEEP levels can cause the Intraventricular septum to shift left?
> 15 cmh20
What else can cause the Intraventricular septum to shift left?
decreased blood volume
If the intraventricular septum is shifted left, what is that going to do to the Left Ventricle Stroke Volume
Decrease it
PPV -> ___________-> compress pulmonary vessels -> Reduce stroke volume -> reduce cardiac and pulmonary blood flow -> high v/q mismatch -> hypoxemia -> decreased o2 content -> reduced o2 delivery
Increase intrathoracic pressure
-> Increase intrathoracic pressure -> compress pulmonary vessels -> Reduce stroke volume -> ____________-> high v/q mismatch -> hypoxemia -> decreased o2 content -> reduced o2 delivery
reduce cardiac and pulmonary blood flow
-> Increase intrathoracic pressure -> compress pulmonary vessels -> Reduce stroke volume -> reduce cardiac and pulmonary blood flow -> high v/q mismatch -> hypoxemia -> _________ -> __________
decreased o2 content
reduced o2 delivery
-> Increase intrathoracic pressure -> _________ -> Reduce stroke volume -> reduce cardiac and pulmonary blood flow -> high v/q mismatch -> hypoxemia -> decreased o2 content -> reduced o2 delivery
compress pulmonary vessels
-> Increase intrathoracic pressure -> compress pulmonary vessels -> Reduce stroke volume -> reduce cardiac and pulmonary blood flow -> _______ -> _______ -> decreased o2 content -> reduced o2 delivery
high v/q mismatch
hypoxemia
T/F PPV can cause a decrease in intrapulmonary shunting?
False.
Can cause an INCREASE in intrapulmonary shunting
T/F ventilation is gravity independent
FALSE
Ventilation is gravity dependent
Ventilation is gravity dependent and areas of lung are ______, where as blood flow is _______
decreased, increased.
Intrapulmonary shunting can increase how much with ppv?
10%
PPV does what to Endocardial (coronary) blood flow
Decreases
PPV reduces Venous return and _______
Cardiac Minute Output
PPV reduces _____ _____ and Cardiac Minute Output
venous return
PPV reduces venous return and CMO and this will cause what to decrease?
Coronary Perfusion
What else can contribute to myocardial dysfuntion?
Ischemia
Compensation in Normal People:
Rarely have a decrease in CMO. The decrease in
stroke volume is compensated for by
_______ and increase in systemic vascular resistance
tachycardia
Compensation in Normal People:
Rarely have a decrease in CMO. The decrease in
stroke volume is compensated for by
tachycardia and increase in systemic vascular resistance
Compensation in normal people
Since most people do not have a decrease in Cardiac Minute Output. The decrease in stroke volume is compensated for by tachycardia and SVR. Also shunts blood away from where?
from the kidneys and other lower extremities
Why would a patient be hypotensive?
Impeded venous return
hypotension is rare due to
Compensation
BP
Increase’s in?
Heart Rate
Systemic Vasoconstriction
Shunt blood away from kidneys and other ext.
Effectiveness of compensation depends upon
integrity of
neuroreflexes.
Pts who are hypertensive increase venous
return to which ventricle
Left ventricle
Pts who are hypertensive increase venous
return to the left ventricle. This is because
pulmonary vessel compression is minimal in
HTN.
Vascular effects can be blocked by
I) pulmonary hypotension II) spinal/general anesthesia III) spinal chord transection IV) polyneuritis V) increased venous return
II, III, IV
High Airway Resistance
In pts with high Raw much of the pressure is
lost to the
poorly conductive airways and
less actually reaches the alveolar level.
Which Patient is less likely to experience hemodynamic changes because less pressure is transmitted to the pleural space?
A) ARF type II B) ARF type I C) ARDS D) COPD E) Patients with compliant lungs and stiff chest wall
ARDS
Pts with stiff lungs (ARDS) , are less likely to
experience hemodynamic changes because
less pressure is transmitted to pleural space.
Which Patient is more likely to experience hemodynamic changes because less pressure is transmitted to the pleural space?
A) ARF type II B) ARF type I C) ARDS D) COPD E) Patients with compliant lungs and stiff chest wall
People with compliant lungs and stiff chest
walls are most are risk.
Effects of lung/ compliance and Raw:
Pts with stiff lungs (ARDS) , are less likely to
experience ___________ changes because
less pressure is transmitted to pleural space.
People with compliant lungs and stiff chest
walls are most are risk.
hemodynamic
Effects of lung/ compliance and Raw:
Pts with stiff lungs (ARDS) , are less likely to
experience hemodynamic changes because
_______ ______ is transmitted to _____ ______.
People with compliant lungs and stiff chest
walls are most are risk.
less pressure; pleural space
Systemic hypotension rarely occurs in normal individuals receiving positive-pressure ventilation due to
compensatory mechanisms.
Beneficial or Harmful effects of Left Ventricular
dysfunction
Beneficial
Duration and Magnitude of PPV
Lower _____ to reduce cardiovascular
changes.
PIP, MAP, inspiratory flow, I:E ratio,
inflation hold and PEEP play a role.
MAP
Duration and Magnitude of PPV
Lower MAP to reduce cardiovascular
changes.
What else play a role.
I) PIP II) MAP III) inspiratory flow IV) I:E ratio V) RR VI) inflation hold VII) FIO2 VIII) PEEP
I, II, III, IV, VI, VIII
Three Points About High Flow
More pressure lost to pt circuit
More pressure will be needed to
overcome Raw
Uneven ventilation occurs with high
flows
Altering vent to reduce PPV complications
What would you reduce?
MAP
Altering vent to reduce PPV complications
MAP increases ____ which leads to (increased/decreased) o2
FRC
Increases
Altering vent to reduce PPV complications
High Insp flow tend to increase ?
PIP
Altering vent to reduce PPV complications
High insp flows tend to increase PIP, but shorten ?
Inspiration
Altering vent to reduce PPV complications
high insp flows tend to increase PIP, but shorten inspiration which can lower
MAP
What occurs with high flow?
Uneven Ventilation
What is the goal with flow?
Flow not too high to cause problems
Flow not too low to cause ^ WOB.
When would you use an INSP hold?
Diagnostically only
What I:E Ratio do you typically want
1 : 2 to 1 :4
What can happen if you have an I:E ratio of 1:1?
Air trapping
Increase in MAP
PEEP = Stiff lungs may not always decrease
CMO
What will PEEP always do to MAP
Increase it
T/F High Peak PIP does always reflect Paw
MAP
FALSE
High Peak PIP does NOT always reflect Paw
MAP
Vent calculations of MAP may not always
be accurate if pt has
auto-PEEP
Vent calculations of MAP may not always
be accurate if pt has auto-PEEP. This is why inflation hold is only used for
plat pressure
What mode can reduce Paw by allowing
spontaneous breathing.
SIMV
PPV can help pts with
LV dysfunction
PEEP may Increase PaO2 and improve ____ _____ dysfunction is due to ______
cardiac perfusion ; hypoxemia
Decreased venous return may
Improve Stroke Volume
