Advanced Ventilation Flashcards
List the complications of mechanical ventlation by ABCD
A:
- Airway malposition (hold ETT, teeth level, secure, CXR)
- Airway obstruction (from resistance/compliance, sputum, citcut)
- Airway trauma eg tracheal stenosis/trachomalacia (from cuff pressure)
B:
- Ventilator aquired pnemonia
- Dependence
- Acute lung injury
- Altered V/Q ratio (increased ventilation to areas with less perfusion, overstretching reducing perfuson)
- Oxygen toxicity
C:
Decreased CO due to:
- Reduced ventricular filling and venous return
- Increased PVR
- Reduced LV compliance
- Increased RV afterload
- Decreased MAP
- Flud retention/oedema (increased ADH, decreased RBF and GFR)
D:
- Increased ICP -> Decreased CPP
- Oedema, hypoxa, pain and anxiety
Other:
- Facial and pressure lesions
- Liver malfunction
- Gastric mucosal ischemia and ulcers
Lst the mechanisms of traumatic injury to the lungs from mechanical ventilaton
- Volutrauma
- Barotrauma
- Alectotrauma
- Biotrauma
Describe volutrauma
High tidal volumes causng overstretching and damage to the alvioli
Describe Barotrauma
Gas under pressure causes alviolar rupture.
Air is then forced into the interstititium of the adjacent broncho-vascular sheath and there is formation of extra alviolar gas.
Increased risk from:
- High PIP and low end expratory pressure
- Emphysema
- High Vt and high PEEP
- Aspiration of gastric acd
Describe alectotrauma
Sheer stress injury to the lung tissue from the repeated opening and closing of lung units.
May occur at times of low Vt +/- inadequate PEEP
*can increase cytokines in lung tissue, then entering the systemic circulation causing MODS.
Describe biotrauma
The release of inflammatory mediators due to injury from mechancal ventilaton (barotrauma/volutrauma/alectotrauma).
Epithelal and endothelal damage causes neutrphils to release cytokines and increase alviolar capillary permeabilty. Increased capillary permeability causes fluid build up between the alvioli and lung capillaries, impairing gas exchange. Also oedema and prurulent meterial build up inside alvioli, decreasing surface area for gas exchange to take place.
Can increase systemc cytokine levels and lead to SIRS and MODS.
Oxygen toxicity is also a form of biotrauma
Define restrictive vs obstructive lung disease
Restrictive
Poor lung compliance - restriction of lung expanson
(can’t breathe in)
Obstrictive
Increased resistance to airflow
(can’t breathe out)
What are examples of obstructive and restrictive lung disease?
Obstructive
Asthma (oedema, hypersecretion, bronchoconstriction)
Emphysema (loss of elastc recoil reduces radius of conducting airways)
Restrictive
Pulmonary fibrosis
ARDS
Fibrosis
Atelectasis
APO
Pneumothorax
Distended abdo
Ventilation management of restrictive lung disease
- Look at pt position
- Increase inspiratory time
- Reduce PIP’s
- Change to pressure control vent
- PEEP to recruit alvioli
- Permissive hypercapnoea
Ventilation management of restrictive lung disease
TBA
Define peak inspratory pressure?
(P peak / PIP)
The maximum pressure in the lung during inspiration
*change in peak pressure with normal Pplat indicates change in airway resistance
Define plateau pressure
End expiratory alviolar pressure - reflects pressure on the volume of gas in the lung at the end of inspiration.
It indicates the compliance of the lungs
It should be <30cmH2O.
>30mH20 can indicate hyperinflation
How do you perform a ‘breath hold’
Perform an ‘end inspiratory pause’ on the ventilator to prevent air moving in or out.
When can you have an obstructive and restrictive lung issue?
In asthma - bronchospasm and gas trapping (auto-PEEP)
Increased PIP/P.plateau difference and an increased P/Plateau
Interperate:
PIP - increased
PPlat - Unchanged or increased
Demonstrate the safe extubation of a patient
