Patient-ventilator asynchronies during mechanical ventilation

Patient-ventilator asynchronies are a mismatch between the inspiratory and expiratory times of the patient and the ventilator.

Complications

  • Increased work of breathing
  • Ineffective effort
  • Air trapping
  • Respiratory alkalosis and hyperinflation of the lungs (Auto-triggering)
  • Dynamic Hyperinflation
  • Auto PEEP (also known as intrinsic PEEP (PEEPi))
  • Alters the outcome of Weaning
  • Increased levels of sedation
  • Confusion about the actual condition of the patient
  • Sleep disorders
  • Longer ICU stay and mechanical ventilation

Trigger asynchronies

  • occurring during the beginning of inspiration
  • Delayed-triggering
    • time interval between inspiratory effort and the delivery of a mechanical breath is increased
  • Ineffective effort:
    • inspiratory effort fails to trigger mechanical breath delivery
  • Auto-triggering:
    • a mechanical breath is delivered without a patient inspiratory effort

Flow asynchronies

  • occurring during the gas delivery
  • Double-triggering:
    • two (or more) mechanical breaths are delivered during one single inspiratory effort
  • Flow asynchrony:
    • delivered flow does not meet inspiratory flow demands
  • Early cycling:
    • mechanical breath duration is shorter than inspiratory effort duration
  • Delayed cycling:
    • mechanical breath duration is longer than inspiratory effort duration

References

  • Arellano, D.H., Palliative Medicine & Care. 2017;4(4):1-6. DOI: 10.15226/2374-8362/4/4/00147
  • Arnal, J.M., Monitoring Mechanical Ventilation Using Ventilator Waveforms, Springer International Publishing. 2018. ISBN: 9783319586540)
  • Dres, M., Current opinion in critical care. April 2016;22(3):246-253. DOI: 10.1097/MCC.0000000000000307
  • Holanda, M.A., Jornal Brasileiro de Pneumologia. 2018;44(4):321-333. DOI: 10.1590/S1806-37562017000000185
  • Mellot, K.G., Critical Care Nurse. 2009 December; 29(6): 41–55. DOI: 10.4037/ccn2009612.
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