There are a number of side effects associated with mechanical ventilation. However one of the biggest problems that has become evident over the years is the risk of Ventilator Induced Lung Injury (VILI).

VILI seems to be induced by high airway pressures and/or large volumes as the main causes.

So what types of injury are induced by mechanical ventilation:

  • Barotrauma
  • Oxygen Toxicity
  • Volutrauma
  • Atelectrauma
  • Biotrauma

Barotrauma

Lung injury caused by excessive pressure. However the condition of the patients lung will be a deciding factor in how much pressure it will take to cause the lung injury.

If they have a very compliant lung, that is one that stretches easily with very little change in pressure then they are less likely to suffer from VILI at lower pressures. The opposite is therefore true if they have non compliant lungs which are more likely to suffer ill effects with lower pressure ventilation.

Keeping the plateau pressure low then becomes important especially in the patient with the compromised lung e.g. the ARDS patient. Research has shown that the plateau pressure should be kept at less than 30cmH20 where possible. For a further explanation of peak versus plateau pressure go here.

Volutrauma

There does however, seem to be evidence that it is the degree of inflation that is likely to cause more damage rather than just the pressure alone. The quoted example of this is the trumpet player who will often create pressures of 150cm H20 without adverse effects. Just as in experiments, if the chest wall in lab rats was restricted using strapping damage was reduced at higher pressures, then those patients with poor chest wall compliance (abdominal distension, massive fluid resuscitation, chest wall deformity, morbid obesity) are at less risk of volutrauma with high volumes.

Volutrauma then is lung parenchymal damage caused by mechanical ventilation similar to ARDS.

It manifests itself with increased permeability of the alveolar membrane, pulmonary oedema, disruption in surfactant production and a decrease in compliance of the respiratory system.

The pulmonary physician in critical care 7: Ventilator induced lung injury. Thorax 2002;57:635–642

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Intubation
6 Ways To Be Better With a BVM
Mechanical Ventilation- Physiologic Effects
Anatomy of Adult ETT
Mechanical Ventilation- Terminology
Mechanical Ventilation- Modes of Ventilation I
Mechanical Ventilation- Modes of Ventilation II
Mechanical Ventilation- Pressure/Volume/Flow Loops
Mechanical Ventilation- Peak Pressure and Plateau Pressure
PEEP (Positive End Expiratory Pressure)
Increase the rate or the tidal volume
Ventilation/Perfusion
Ventilation Screen- What do some of those numbers mean?
Phase Variables
I:E ratios and total cycle time.
Why do we ventilate?.
Volume controlled ventilation and compliance.
Lung compliance.
How do I describe how my patient is being ventilated?
Pressure/Volume loop
AC versus SIMV
A-a gradient
Pressure Support
Pressure Support Ventilation Curves
Pressure/Volume/Flow Curves
Ventilator Induced Lung Injury
Trigger, Limit and Cycle
Ventilator Associated Pnuemonia

 

Jevon

Jevon

Possibly the book I most highly recommend for nurses to use as their pocket guide. Phil Jevon is a practitioner in Walsall and has produced an easily read, pocket sized tool. You can click on the picture above  to purchase this excellent book.
Talley and O'Conner
Slightly less 'weighty' than Macleods but still with lots of useful detail and information. The latest copies also have a CD with good, well narrated examples of clinical examination.
Macleods
This title is 'Highly Commended' in the 2006 British Medical Association Awards! 'an incredibly thorough book which is very well illustrated - a must in a book explaining how to perform examinations' - ("Medical Student Review"). This book will show you how to: talk with a patient; take the history from the patient; examine a patient; formulate your findings into differential diagnoses and rank these in order of probability; and, use investigations to support or refute your differential diagnosis.