emDOCs Podcast: Episode 48 – Ventilator Management

Today on the emDOCs cast with Brit Long, MD (@long_brit) and Skyler Lentz, MD (@SkylerLentz), we cover managing the ventilator in the ED setting.


Episode 48: Ventilator Management

Background:

  • Managing the ventilator and ensuring appropriate settings are vital; these have a significant impact on patient outcomes.
  • LOV-ED Trial: Quasi-experimental, before-after study, evaluating a multifaceted ED-based mechanical ventilator protocol. This targeted lung-protective tidal volume, appropriate setting of positive end-expiratory pressure, rapid oxygen weaning, and head-of-bed elevation.
    • Authors found increased ventilator-free days, ICU-free days, and hospital-free days with protocol.
    • The mortality rate was 34.1% in the preintervention group and 19.6% in the intervention group with the protocol (adjusted OR 0.47; 95% CI 0.35 to 0.63).
    • Fuller BM, Ferguson IT, Mohr NM, Drewry AM, Palmer C, Wessman BT, Ablordeppey E, Keeperman J, Stephens RJ, Briscoe CC, Kolomiets AA, Hotchkiss RS, Kollef MH. Lung-Protective Ventilation Initiated in the Emergency Department (LOV-ED): A Quasi-Experimental, Before-After Trial. Ann Emerg Med. 2017 Sep;70(3):406-418.e4

 

Goals:

  • Utilize appropriate tidal volume
  • Limit and measure plateau pressure
  • Set appropriate PEEP
  • Avoid hyperoxia, ventilate appropriately
  • Head of bed up, OG to decompress stomach and decrease aspiration
  • Appropriate analgesia and sedation

 

Settings:

  • Tidal Volume
    • Tidal volume 6-8 ml/kg IDEAL body weight
    • Modes: Volume vs. pressure (most In ED use volume, which gives a guaranteed volume).
    • Assist control vs. SIMV – pick a setting that allows set volume and respiratory rate (RR).
  • Respiratory Rate
    • 10 to 30 breaths per minute (depends on underlying etiology)
    • Lower RR for obstructive lung disease (permissive hypercapnia) and higher RR for metabolic acidosis (compensation to blow off CO2).
    • Effects minute ventilation and expiratory time.
    • Watch for air trapping in obstructive lung disease.
  • PEEP
    • 5 cm H20 for most
    • Obese or severely hypoxemic from ARDS (bilateral infiltrates) need more start at 8-10 cm H2O
  • FiO2
    • Avoid hyperoxia – reduce FiO2 as soon as feasible and safe.
  • Pressures
    • Peak pressure goal < 30-35 cm H20
      • This is the sum of all pressures in volume targeted modes, includes airway resistance.
    • Plateau pressure goal < 30 cm H2O
      • This is the pressures in the small airways and alveoli; what we are primarily concerned with.
      • Measure with end-inspiratory hold
    • Alarms:
      • High peak and normal plateau – resistance problem
      • High peak and high plateau – compliance problem

 

Putting it all together:

  • Acute lung injury/ARDS-bilateral infiltrates
    • Problem: Injured alveoli cannot accept volume and exchange oxygen as well as healthy alveoli
    • Higher PEEP, plateau < 30 cm H20, Vt 4-6 ml/kg
  • Obstructive lung disease
    • Problem: Obstruction and limitations in exhalation.
    • Lower RR, monitor for air trapping, permissive hypercapnea/pH 7.2 is ok

 

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