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MV DISCONTINUATION

VIEWS: 9 PAGES: 23

									RC 171: UNIT 7
 Overview
 Reasons  For Vent Dependance
 Patient Evaluax
 Weaning Methods
 Selecting A Method
 Pt Monitoring During Weaning
 Failure To Wean & Terminal Extubation
 MV  should only be applied for as long as
 it takes to resolve the contributing factors
 to the respiratory failure
 • Acute - <72 hrs
 • Vent dependant - > 1-2weeks
 • Permanently vent dependant - >3 months
  failed weaning
 Sometimes Vent support can be D/C’d
 while maintaining an artifixl airway
  • MV Discontinuax
  • Weaning
  • Extubax
 Determinants      of Ventilatory workload
  • Level of ventilax needed
     Metabolic rate,
     CNS drive
     Dead space
  • Lung mechanics
     Compliance
     Resistance
  • Imposed WOB
     Artifixl airway & other mechanical factors
 Demand        v. Capability
  • Respiratory Insufficiency = Ventilatory demand
      > capability
       Will lead to respiratory failure

 Inabilityto reverse causes leading to
 initiation of MV
  •   Ventilax
  •   Oxygenax
  •   CV function
  •   Psychological
  •   Other Multi system causes
 Oxygenax
 Ventilax
 Ventilax Mechanics
 Resp muscle strength
 Ventilatory Demand
 Other Body Systems
 Evaluax of Airway
 Oxygenax
 •   FiO2          <0.5
 •   PEEP          <8 (5) cmH2O
 •   PaO2          >60 mmHg
 •   SaO2          >90%
 •   P(A-a)O2      <350 mmHg
 •   PaO2 / FiO2   >150
 Ventilax
  • PaCO2    <50 mmHg
  • pH       >7.35
 Ventilatory      Mechanics
  •   Rate             <30 bpm*
  •   Vt               >5 ml/kg
  •   VC               >10 ml/kg
  •   Clstatic         >25 ml/cmH2O
  •   RSBI or f/Vt     <105
  •   Appearance
       Weak shallow breathing
       Respiratory paradox
        Alternating abdomen & chest wall breathing
       Grunting, retracting, nasal flaring, accessory muscle use
        & thoracic cage support
 Respiratory   Muscle Strength
  • NIF          < -25 mmHg*
 Ventilatory   Drive or Demand
  • Ve           <10 l/m
   Other systems
    • Metabolic
       Adequate Nutrix provided to maintain muscle strength & mass
           High in proteins
           Too many carb’s can increase CO2 produx
    • Renal & electrolytes
       BUN & Cr
       Urine output, at least 1 l/day
    • Cardiovascular           T47-2 p1161
       CO & CI
       Rate & rhythm
       Blood pressure
           Syst, Diast, & MAP
           CVP’s, PA, & Wedge when available
    • Psychological & Neural
         Stable Ventilatory drive
         Adequate secrex clearance
         Airway protex
         Level of consciousness
 Airway    Evaluax
  • Even though ready to d/c MV, may not be
   ready to extubate
    Ability to protect airway & remove secrexs
  • Edema or inflammax (swelling)
     Leak test
     Deflate cuff, if no swelling is present you should have a
      significant cuff leak.
     If severe swelling is present you will observe little or no
      leak
 Airway   Eval Cont’d
 • Stridor
    Squeaky high pitched wheeze indicating
     dangerous narrowing of the glottis
    Treated with
    Racemic epinephrine
      0.5 ml of 2.25% epinephrine in 3ml NS nebulized
    Cool Aerosol w/ supplemental O2
    Dexamethasone (decadron)
      1mg in 4 ml NS nebulized
      Or IV injex
 Spontaneous   breating trial
 SIMV
 PSV
   Spontaneous Breathing Trial (SBT) B47-8 p1165
    • Placed on T-Tube, Trach collar, Tube comp, or ps 5/peep5
    • Multiple trials per day of SBT followed by vent support for
        muscle recovery
    •   Initial trial is evaluated after only a few minutes, if pt is ok
        the trial is extended
    •   Subsequent trials are extended until pt is able to stay off
        vent all day, and rest on vent at noc
    •   Eventually vent goes on standby and pt only uses it prn
    •   Failed SBT’s require 24 hr vent rest before attempting
        again
         Important not to push your pt to the failure point
         Multiple Short trials are more benefixl than one long trial to
          failure point
    • Patient types
       <72 hrs of MV
       Quickly reversed condition once unsedated (Trauma)
   SIMV weaning
    • Involves gradual redux of mechanical rate based on
      pt assessment
    • 2 methods of SIMV weaning
      Gradual
       Begin with full support, reduce Ventilatory support in a stepwise
        fashion until complete spontaneous breathing is achieved
       Rebuilds muscle strength and coordinax gradually
      Abrupt
       As soon as pt can breathe spontaneously you limit mechanical ventilax
        to that which is only necessary to make up for the difference b/w the pt
        capability & their demand
    • In any case SIMV weaning has proven to be
     inefficient weaning when compared to SBT or PSV
 PSV
 • PSV max
    PS adjusted to provide 8-10 ml/kg (i.e. full support)
    Once the pt can breathe spontaneously, PS is
     reduced to minimal levels only to make up for loss
     of anatomical peep & resistance caused by the
     artifixl airway (ATC or 5/5)
 Method   is Patient Dependant
 • Every pt situation is different & may require
   various variaxs to the three methods of
   weaning.
 • Each case should be considered & initiated
   based on the best fit for the scenario
   Continuous adjustment or switching of methods
    may be needed as the trials succeed or fail
 Same parameters as are used to judge
 readiness to wean or to initiate MV
 •   Oxygenax
 •   Ventilax
 •   Ventilatory mechanics
 •   resp muscle strength
 •   Ventilatory drive
 when a pt is unable to wean, either
 because of failure or physical inability,
 the will be deemed permanently vent
 dependant
  • failure to wean for >3 months
 These   pt’s will find homes in LTAC
  • Long term acute care
 Orat home with help of family & home
 health organizations
 Terminal Weaning
  • When a pt is extubated due to catastrophic or
    irreversible illness
  • Based on medical & family decisions/choice
  • When extubax will surely lead to death
    w/draw of life support measures

								
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