1
Q
Mechanical Ventilation
A
A machine that generates a controlled flow of gas into a patient’s airway
- O2 and air are generated from cylinders or wall outlets
- gas is blended according to prescribed “inspired oxygen tension” -FiO2
2
Q
Indications for Ventilation
A
- ventilatory failure
- inability to protect the airway
- failure to clear the airway
3
Q
Airway Accesses
A
- non-invasive ventilation (nasal cannal, face mask, non-rebreather mask, BiPAP)
- LMA
- Endotrach tube
- Tracheostomy (for prolonged intubation)
4
Q
Types of Ventilators
A
- Negative-Pressure Ventilators
- Positive-Pressure Ventilators
- Non-invasive Ventilation
5
Q
Negative-Pressure Ventilation
A
Creates negative pressure externally to draw the chest outward and air into the lungs
- mimics spontaneous breathing
- used for individuals with neuromuscular disorders
6
Q
Positive-Pressure Ventilation
A
- PUSHES air into the lungs
- can be invasive and non-invasive
- amount of air delivered in: volume (mL) and specific pressure
- Used for individuals with Acute Resp. Failure
7
Q
BiPAP
A
- Provides ventilator support, but uses a tight fitting mask
- used to AVOID intubation
- supportive for patients with: sleep apnea, impending respiratory failure
- success varies and is limited to patient tolerance
8
Q
CMV
A
- Controlled Mechanical Ventilation
- breaths are delivered regularly and independent of the patient’s own ventilatory efforts
- used when the patient has NO DRIVE TO BREATHE
- very rarely used
9
Q
ACV
A
Assist-controlled mechanical ventilation
- vent breath is triggered by patient inspiration
- used to initiate mechanical ventilation, those at risk for respiratory arrest
- if the patient does not initiate a breath in a preset time to vent fires a breath at the pre-set Vt
- allows patient to breath faster, but not slower (can breathe over the ventilator, such as 20 per minute, but wont let it fall below say 10 BPM)
10
Q
SIMV
A
Synchronous Intermittent Mandatory Ventilation
- allows the patient to breath spontaneously without vent assistance between delivered vent breaths
- vent has a pre-set rate and tidal volume and will not fire when the patient produces their own breath
- COORDINATED with the patient’s own resp effort
11
Q
SIMV commonly used to:
A
- Support ventilation
- Exercise the respiratory muscles between vent-assisted breaths
- During the weaning process
12
Q
“SIMV of 4 and pt’s RR is 18”
How many spontaneous breaths is your patient taking?
A
14 (on their own)
13
Q
VT
A
Tidal Volume
volume of air delivered during each ventilator breath
N: 6-10 mL/kg or approx. 400-500 mL
14
Q
↑ VT
A
↑ risk of barotrauma & ↓ venous return/CO
15
Q
↓ VT
A
↑ risk of atelectasis
16
Q
PaO2
A
how much oxygen is available is in the alveoli
17
Q
SaO2
A
how much oxygen is bound to hemoglobin
18
Q
Oxygen (FiO2)
A
- set at the lowest possible level for adequate tissue perfusion
- FiO2 can be 21% to 100% oxygen
- Try to keep FiO2 less than or equal to 50% to avoid oxygen toxicity or fibrosis
- Often have set parameters to keep SpO2 > 90% and PaO2 >60
19
Q
Hypoxemia
A
results from ventilation or circulatory problems
-VQ Mismatching (shunting)
20
Q
Normal RR
A
12 to 20
21
Q
PEEP
A
Positive End-Expiratory Pressure
- maintains positive pressure in the lungs at the end of expiration
- improves the VQ relationship and diffusion across the alveolar-capillary membrane
22
Q
PEEP prevents
A
- atelectasis
- reduces hypoxemia
- allows for a lower % of FiO2
23
Q
PEEP helps in a code by…
A
helping with venous return during chest compressions
24
Q
PSV
A
Pressure Support Ventilation
- Preset pressure delivery augmenting patient own resp effect
- Applies positive pressure during “spontaneous” inspiration
- Can be used with all modes of ventilation
25
PSV used to...
- overcome dead space of circuit and pt's airways
| - decreases the work of breathing
26
CPAP
Continuous Positive Airway Pressure
- elevates end-expiratory pressure during spontaneous breaths
- used for intubated and non-tubated patients
27
CPAP used to...
- maintain open airways
| - decrease the work of breathing
28
CPAP Mask or BiPAP
- used to improve oxygenation on patient's who can breath on their own
- used for those experiencing sleep apnea at night
- masks must be very tight on the face
29
High Pressure Limit Alarm
- secretions or condensation in tubing
- Kink in vent tubing
- Biting ETT
- coughing or gagging
- bronchospasm or pneumothorax
30
Low Pressure Alarm
- vent tubing disconnect
| - displaced OETT or Trach tube
31
High Respiratory Rate Alarm
- Anxiety or pain
- Secretions
- Hypoxia
- Hypercapnea
32
Low Exhaled Volume Alarm
- Vent tubing disconnect
- Cuff leak or inadequate cuff seal
- Another occurring alarm preventing breath delivery
33
Improper Tube Placement
- inflated lung vs. uninflated lung
- gastric distention
- aspiration
- facial skin necrosis
- crepitus
- drying of eyes and MM
- stress
- claustrophobia
34
Hospital Acquired Pneumonia
- normal respiratory defense mechanisms bypassed
- open epiglottis
- cough/gag reflexes inhibited or impaired
- secretions often think and tenacious (increases risk of atelectasis)
35
What is vital in preventing HAP?
-hand hygiene
36
Complications of Mechanical Ventilation
- Aspiration
- Oxygen toxicity
- Resp. acidosis/alkalosis
- Failure to wean
- ↓ BP and CO
- Possible liver and renal dysfunction
- ↑ intracranial pressure
- fistulas
- barotrauma
- fluid retention
- loss of muscular conditioning
- malnutrition
37
Ventilator Weaning
- process of removing ventilator support and re-establishing spontaneous, independent breathing
- Duration of periods off the vent is gradually increased until patient can maintain adequate independent respirations for several hours
38
Process of ventilator weaning depends on...
- preexisting lung conditions
- duration of mechanical ventilation
- patient's general condition - physically and psychologically
39
_____ and ____ are used for weaning
SIMV and PSV
40
Weaning is done when...
duration of mechanical ventilation has been longer and respiratory muscle reconditioning is needed.
41
Using SIMV to wean...
- number of vent assisted breaths are gradually decreased
| - when pt is able to tolerate an SIMV of 4 bpm, a T-piece or CPAP weaning is attempted
42
Using PSV to wean...
Pressure support levels are gradually decreased
-when PSV is just enough to overcome ETT resistance, support is D/C, pt is extubated
43
Terminal wean
gradual withdrawal of mechanical ventilation when survival without assisted ventilation is NOT expected
44
Nursing considerations
- need to discuss option with pt/family/SO
- when? where? what?
- provide education and comfort
MS2 Exam 1
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