Lung recruitment maneuver

Background

  • Controversial in terms of safety and efficacy
    • No mortality/morbidity outcome benefits
    • May be of more benefit to extra-pulmonary ARDS than to pulmonary ARDS
  • Multiple methods reported
    • Below is only one method
    • Refer to your RT for hospital protocol
  • Severe ARDS in which PaO2 recalcitrant to maximal ventilator settings, APRV, PCV
  • Biotrauma and cytokine release occur due to:
    • Dependent areas of airway are collapsed throughout TVs
    • Cyclic collapse causes shear injury atelectrauma with each breath
    • Least dependent areas inflated throughout TVs are also easily hyperinflated causing volutrauma and barotrauma, especially in:
      • TVs > 6 cc/kg
      • Pplat > 30-35 cmH2O
  • Derecruitment of alveoli occurs due to[1]:
    • Standard low TV ventilation in ARDS
    • Insufficient PEEP
    • High FiO2 absorptive atelectasis
  • Goals to recruit alveoli and maintain with PEEP to prevent cyclic collapse

Risks

  • May only be temporary benefit
  • Hemodynamic instability with drop off in preload
  • CO2 retention
  • May worsen oxygenation by shunting blood to poorly aerated lung (opposing physiological hypoxic pulmonary vasoconstriction)
  • May worsen ventilator-induced lung injury with volutrauma/barotrauma
  • Pneumothorax
  • Contraindications
    • Unstable BP
    • Ptx or high risk of ptx (blebs, necrotising pna)
    • ARDS > 1 wk (relative contraindication)

Procedure[2]

  • Goal is to find the derecruitment point

Failure

  • Before attempting, know when the maneuver should be stopped
  • Stop and return to baseline PCV settings if:
    • HR < 60 bpm
    • HR > 140 bpm
    • New dysrhythmia on monitor (may indicate significant respiratory acid-base shift)
    • SBP < 80 mmHg
    • Sustained SaO2 < 85%
    • Drop in dynamic compliance (pneumothorax)

Preparation

  • May require increased sedation or paralysis
  • Optimize preload (maneuver decreases preload)
  • Maintain a very reliable, good waveform SaO2 (that matches ABGs)
  • Pressure control ventilation using current rate, PEEP, FiO2
    • I:E to 1:1
    • Adjust FiO2 to SaO2 90-92%
  • Record baseline VSs and vent settings
    • Take note of dynamic compliance levels
    • Maintain appropriate minute ventilations
  • 14 ga needles x2 in case of pneumothorax

Increasing PEEP

  • Adjust PC level (Pi) above PEEP to maintain TV at 6 cc/kg
  • Adjust RR to maintain appropriate MV, not any > 35 bpm
  • Increase PEEP to 15 cmH2O
    • Go on with protocol if < 20% SBP drop
    • If unstable BP or SBP drop > 20%, halt procedure
  • Increase PIP (peak insp pressure) to 40 cmH2O
  • Set PC level to 15 cmH2O above PEEP
    • Maintain this difference between PEEP and PC level (Pi)
    • Increase q2 minutes PEEP to 20 --> 30 --> 40 cmH2O
      • Pi will reach 55 cmH2O
      • Note maximum SaO2 obtained
      • Treat SBP drops as necessary, but halt procedure if > 20% SBP drop despite pressors/fluids
    • Increase PIP as necessary
      • Maintain minute ventilation
      • Reduce RR before PIP increase since TV will increase

Reducing PEEP

  • Reduce q3 minutes PEEP to 25 --> 22.5 --> 20 --> 17.5 cmH2O
  • Remember that SpO2 monitor disaplys results up to 1.5 min after clinical change
  • Until:
    • Decrease in SaO2 of 1% from maximum SaO2 observed, which is the derecruitment point
    • OR minimum of 15 cmH2O PEEP reached

Re-recruitment

  • Increase PEEP step-wise q2 minutes to 40 cmH2O again
  • Maintain PEEP at 40 cmH2O for 2 minutes
  • Return to PEEP level 2-4 cmH2O above decruitment point
  • Adjust TV 4-6 cc/kg and plateau pressures < 30 cmH2O
  • Tolerate permissive hypercapnea if pH > 7.15
  • May increase RR up to maximum of 38 bpm

Adjuncts

See Also

References

  1. Nickson C. Lung Recruitment Maneuvers. 21 Sept 2014. http://lifeinthefastlane.com/ccc/recruitment-manoeuvres-in-ards/
  2. Medical College of Georgia. Open Lung Tool Procedure Protocol. Updated 2014.