Liberation from mechanical ventilator

doi:10.15406/jlprr.2015.02.00046

Journal of

eISSN: 2376-0060

Lung, Pulmonary & Respiratory Research

Opinion Volume 2 Issue 4

Liberation from mechanical ventilator

Patriciaÿ Colgan, Ibrahim Mohd Fawzy M A Hassan, Mohammad Faisal Abdullah Malmstrom, Abdul Aziz Ahmed M. Alhashemi, Thiruppathi Cho ckalingam,

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Ashokÿ Parchani, MP Sujith, Mahesh Chandra, Damodaran CU, Flordevic P Guerra, Talibÿ Yaseen

Hamad Medical Corporation, Qatar

Correspondence: Thiruppathi Chockalingam, Acting Assistant Director of Respiratory Therapy, Hamad Medical Corporation, 3050 Doha, Qatar, Tel (+974) 55319021, Fax (+974) 44391829

Received: March 12, 2015 | Published: April 10, 2015

Citation: Colgan P, Hassan IMFMA, Malmstrom MFA, et al. Liberation from mechanical ventilator. J Lung Pulm Respir Res. 2015;2(4):64–66. DOI: 10.15406/jlprr.2015.02.00046

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Objectives

Discuss the variables that are used to indicate readiness to wean from mechanical ventilation Discuss the use of protocols to wean patients from ventilatory support Discuss the criteria used to indicate readiness for extubation Describe the most common reasons why patients fail to wean from mechanical ventilation.

Predicted success rate

75% of mechanically ventilated patients are easy to be weaned off the ventilator with simple process 10-15% of patients require a use of a weaning protocol over a 24-72hours 5-10% require a gradual weaning over longer time 1% of patients become chronically dependent on MV

Assessment criteria for weaning

Neurological: (No sedation, GCS>8,Pain controlled)
Respiratory: (NoWOB, PS <10,PEEP 5,FIO2-40%,sat >90%, PF >200)
Cardiovascular : (Stable Hemodynamics, Hb >7, Normal ECG)

Ventilation status

Intact ventilatory drive: ability to control their own level of ventilation
Respiratory rate <30
Minute ventilation of <10 L to maintain PaCO2 in normal range
VD/VT <60% (Vd/Vt=0.320+0.0106 (PaCO2 - end-tidal carbon dioxide measurement)+0.003 (RR per minute)+0.0015 (age in years )
Functional respiratory muscles

Intact airway protective mechanism

Intact ventilatory drive: ability to control their own level of ventilation
Respiratory rate <30
Minute ventilation of <10 L to maintain PaCO2 in normal range
VD/VT <60% (Vd/Vt=0.320+0.0106 (PaCO2 - end-tidal carbon dioxide measurement)+0.003 (RR per minute)+0.0015 (age in years )
Functional respiratory muscles

Approaches to weaning

Spontaneous breathing trials
Pressure support ventilation (PSV) SIMV
New weaning modes

Maximal inspiratory pressure

Negative Expiratory pressure must be more than -20cmH2o
Assures ability to mobilize secretions

Shallow breathing index

Index of rapid and shallow breathing=RR/Vt in litre

Single study results

RR/Vt>105 95% wean attempts unsuccessful
RR/Vt<105 80% successful
One of the most predictive bedside parameters

Spontaneous Breathing Trial (SBT)

Explore Exclusion Criteria
Assess Readiness for SBT
If passed proceed sedation vacation for 30min
Initiate SBT for 30minutes
Assess the tolerance to SBT
If SBT passed assess Readiness for Extubation

Exclusion Criteria for SBT

GCS <8 unsedated use of Neuro muscular drugs
Neuro Muscular Disease with VC <20ml/kg or NIP <20
RASS sedation and agitation scale +1 and higher, -3 and lower
Immediate pending Invasive procedure
ICP >20 or needing RX in last 12hours
Ongoing Cardiac Ischemia
Uncontrolled seizures

Failure to wean

Weaning to exhaustion
Auto-PEEP
Excessive work of breathing
Poor nutritional status
Overfeeding
Left heart failure
Infection/fever
Major organ failure
Technical limitation

Appendix

Protocols

Developed by multidisciplinary team
Implemented by respiratory therapists and nurses to make clinical decisions
Results in shorter weaning times and shorter length of mechanical ventilation than physician-directed weaning

Points to remember

The primary prerequisite for weaning is reversal of the indication of mechanical ventilation
Adequate gas exchange should be present with minimal oxygenation and ventilatory support before weaning is attempted
The function of all organ systems should be optimized, electrolytes should be normal, and nutrition should be adequate before weaning is attempted
The most successful predictor of weaning is RSBI <100
Maximum inspiratory pressure is the best predictor of weaning failure
Ventilatory discontinuation should be done if patient tolerates SBT for 30-120minutes
Use of liberation and weaning protocol facilitates the process and decreases the ventilator length of stay.^1–4