Mechanical Vent Review Flashcards
What are the differences between normal and mechanical ventilation?
Normal: negative pressure, intrapleural, pulmonic and thoracic pressure becomes negative.
Mechanical vent: positive pressure, intrapleural remains negative but intrapulmonic becomes positive as well as intrathoracic
Whatare two physiological effects of mechanical ventilation?
1:decreased venous return due to increased intrathoracic pressure (decreased preload
2:mechanical ventilation will falsely increase cvp values.
Types of respiratory failure
Type 1: hypoxic( gas exchange)
Type 2: hypercapnia (ventilation)
4 physiological reasons for mechanical ventilation
Support alveolar ventilation,support gas exchange, increase lung volume, reduce WOB
Endotracheal intubation indications
Failure to oxygenate, ventilate, maintain/protect, clinical progression.
ET tubes are for short-med timeframe, Trach is for long term.
Define flow
Volume moving across time
Mechanical ventilation is made Up of 3 components, what are they?
Flow, volume, pressure
What is the relationship between volume and pressure?
Volume and pressure are inseparable, an increase in volume results in increased pressure
How does flow relate to volume and pressure?
- Flow is volume moving across time, flow creates volume, and volume creates pressure.within a space.
What are 3 major goals of mechanical ventilation?
Decrease WOB, support/optimize oxygenation and ventilation, balance pH
What are 4 things a vent cannot do for a pt.
A vent cannot… Assist w/cellular gas exchange, aid transport of gases, influence cellular uptake, force pt to exhale (asthma)
What are the 4 modes of classic ventilation.
Assist /control mode, synchronized intermittent mandatory ventilation (simv), pressure control, pressure support
What is a controlled breath?
A breath that is completely controlled by the ventilator. The patient does nothing.
What is an assisted breath?
The vent senses a change inpressure or flow, this is a triggered breath. When sensed a breath is delivered.
When volume is a set perimeter, what will vary ?
Pressure will vary
When pressure is a set parameter, what will vary?
Volume will vary
Define assist control parameters.
RR + vt are set, pressure will vary, peep is an adjunct. Pt can initiate additional breaths
Define SIMV + parameters
Combination of A/C and spontaneous breathing.
The vent will delivery mandatory set breathes with set vt in coordination with the patients own breaths.
.set parameters include: RR sync with pt., tidal volume, pressure support to help pt initiated breaths.
Define pressure controlled ventilation + set perameters
The vent will deliver a set number of breaths per min until a set pressure is reached. This is a time cycled, pressure limited mode of ventilation. Volume will vary.
Set parameters include pressure control, rr, inspiratory time.
What components make up the i:e ratio?
RR+ i-time
Define pressure Support + perameters
Adjunct not a mode of ventilation. PSV provides an inspiratory boost to spontaneously breathing patients.
Set parameters are pressure (5-20 cmh2o)peep
How is Vtcalculated?
Based on ideal body weight (6 -8ml/kg)
ARDS 4-8ml/kg
Define peak-flow
The speed of gas flowing from the machine and into the lungs. Measured in litres / min. Not monitored.
What is the preferred airway for patients requiring long term ventilatory support
Tracheostomy
What is the most common airway adjunct for short to medium term ventilation ?
Endotracheal intubation
The section circled on the endotracheal tube is the end that
Attaches to the ventilator tubing
What is the function of the circled area on an endotracheal tube?
The cuff inflation port
What should ETT cuff pressures be maintained at?
20-25mmHg pressure
Nursing responsibilities during intubation include
Monitoring and supporting the patient and administering medications
Medications typically given during RSI
Analgesic, sedative, paralyzing agent
How long should each ETI attempt be limited to
30 seconds
When viewed on CXR, how many cm above the carina should the ETT be?
3-4cm
After ETI is complete and confirmed with ETCO2, what 3 tasks should be completed?
-cm at the teeth
-secure ETT
-Document
What four values does the ventilator use to determine when inspiration should end?
-time
-flow
-pressure
-volume
What is the variable that initiates change from exhalation to inspiration?
Trigger
For a patient in volume control, which changes to the ventilator will reduce PaCO2?
Increase in RR or Vt
For a patient on pressure control ventilation, which of the following changes to vent settings would reduce PaCO2
Increase set pressure
Increasing PEEP on a ventilatory does what to the body?
Increases baseline intra thoracic pressure and decreases venous return
How will mechanical ventilation impact the GI system?
-increases the risk for gastric ulceration
-increases the risk for gastric distension
When does absorption atalectasis occur?
When the FiO2 is close to 1.0
In practice, how are the adverse effects of high concentrations of oxygen minimized?.
The use of PEEP, using the minimal amount of fio2 possible
How frequently should a patients readiness to be weaned be assessed?
Everyday
What parameters are used for the RSBI (Rapid shallow breathing index)
RR/Vt
Ability to obey commands is an essential part of the criteria indicating a patients readiness to wean
True or False
FASLE.
Ability to obey commands is not part of essential criteria.
For the long term ventilated patient, weaning is complete after how many hours of spontaneous breathing.
24hours
Minimizing dead space is achieved by
Optimizing cardiac output
In type 1 respiratory failure. How can oxygen supply be improved?
-increasing driving pressure
-decreasing V/Q mismatching
-reducing system effects of hypoxia
