Weaning and extubation

weaning and extubation is an art more than science. easy reckoner for pediatric pg's and fellows to know the fundamental principles

1. Weaning and extubation and management of sedation withdrawal Dr C Abhiram Kumar Fellow in PICU Aster CMI Hospital

2. Introduction Weaning Techniques of weaning Predictive indices for weaning Weaning failure Extubation Extubation failure Role of tracheostomy Sedation withdrawal Management of sedation withdrawal

3. The thought of weaning should begin from the day of intubation. Too early or too late extubation have their own adverse consequences 60% of accidental extubations donot require reintubation

4. Weaning- transition from ventilatory support to spontaneous breathing during which time patient assumes the responsibility for effective gas exchange while positive pressure support is reduced Extubation - The process of removal of the endotracheal tube

5. When to consider weaning??? Whether the disease is resolving or stable? Is there adequate gas exchange? Are the hemodynamics stable? Is the patient having good respiratory drive?

6. Techniques of weaning Old methods- Full support Partial support-SIMV/PS CPAP T-piece trial New method Establish readiness of weaning SBT Weaning parameters

7. Spontaneous Breathing T rial(SBT)- Subjective determination of whether the underlying disease process necessitating mechanical ventilation has improved to allow adequate gas exchange with spontaneous breathing SBT using T-piece trials/ PSV/ CPAP Initial screening and then 30-120min if tolerating End SBT if patient shows signs of failure

8. Monitoring parameters on SBT Overall comfort status Mental status Respiratory rate and pattern Hemodynamic stability Satisfactory gas exchange Effective cough

9. Criteria for failure of SBT Anxiety, diaphoresis Agitated or drowsy RR> 95 th centile for age Increased use of accesory muscles Inability to maintain effective ventilation(<5ml/kg) Increase in HR >20% from baseline Hypertension or hypotension pH<7.3/ pCO2 >50mm Hg or more than 10 from baseline

10. Management of SBT failure Ventilatory muscle rest Assesment of factors responsible for failure Correction of factors New attempt after 24hrs

11. Predictive indices of weaning Over 60 predictors of weaning success RSBI and CROP index more commonly used. RSBI- RR/VT(in L). <8bpm/ml/kg 63% sensitivity CROP Index-dynamic compliance, RR, oxygenation, maximum inspiratory effort Cdyn * Pimax * PaO2/PAO2/ F >0.18ml/kg/ bpm

12. Factors contributing to weaning failure A- Acid Base status B- Breathing/respiratory factors C- cardiac factors D- Drugs and neurologic status E- Electrolyte imbalance Nutrition Psychological status

13. Extubation feasibility Controlled underlying disease No high dose of vasoactive drug Approved SBT FiO2<0.4 with SPO2>92%/ PF ratio >150MM HG PEEP <5-8cm H2O RSBI<8 cpm /ml/kg Intact airway reflexes Adequate conscience level No/minimal UAO(Cuff leak test)

14. Cuff Leak Test Predicts upper airway patency Deflate the cuff Hear for the leak of air If no leak- chances of extubation failure high

15. Technique of Extubation Withhold feeds for atleast 6 hrs prior to extubation Position in semifowler position Give 100% oxygen Physiotherapy and ET suctioning Oropharyngeal suctioning before cuff deflation Withdraw tube during positive pressure inflation with AMBU bag Administer humidified oxygen with head end elevated

16. Post E xtubation Complications 1. Stridor- U sually self limiting R arely require steroid and/or nebulised adrenaline Can be minimised by administration of corticosteroids 6-12 hrs prior to extubation 2. Upper Lobe Atelectasis- Due to microaspirations Managed by postural physiotherapy/ 02/ CPAP

17. Extubation failure Reintubation within 24-48 hrs of extubation Early- reintubation within 6hrs Intermediate- reintubation within 6-24 hrs Late- reintubation from 24-48 hrs of extubation

18. Sedation withdrawal Tolerance- development of a need to increase the dose of a drug to achieve the same effect of the drug which was previously achieved at a lower dose Physical Dependance - also called as neuroadaptation . Repeated administration of a drug which necessitates it’s continuous administration to prevent the appearance of withdrawal or abstinence syndrome that is characteristic to that drug

19. Drugs that commonly cause abstinence syndrome in PICU- Opioids, Benzodiazepines, alpha agonist Withdrawal syndromes usually develop after 3-5 days of continuous infusion and after 10days of intermittent therapy Dependance also depends upon the duration of receptor activation

20. Withdrawal assessment tools WAT-1- Consists of four components 1.review of patient records for past 12 hours 2.observation of the patient for 2 minutes 3.patient assessment during a progressive stimulated exam to assess the level of consciousness at beginning of each 12 hour shift 4.assessment of poststimulation recovery

21. Benzodiazepine withdrawal-occurs on abrupt cessation of bezodiazepines . Symptoms include anxiety, tremors, palpitation, diaphoresis, headache and nausea Signs include tachycardia, hypertension, diaphoresis, tachypnea

22. Weanig strategies- If used for 3-5days- Initiate withdrawal assessment tool every 4-6 th hlry and continue for 1-2 days after cessation of the drug Reduce benzodiazepine administration by 20% of pretapered dose everyday Idf withdrawal symptoms occur, stop weaning for 24 hrs If withdrawal symptoms persist then increase the dose to previous dose and consider adding clonidine

23. If used for 10days- Follow above guidelines Slower tapering of drug by 10% of pretapered dose every day If withdrawal symptoms develop stop weaning for 24 hrs If withdrawal symptoms persist then increase the dose to previous dose and consider adding clonidine

24. Conversion strategies for benzodiazepines Iv midazolam to oral lorazepam - 1 .Calculate the last 24 hr midazolam infusion dose 2.Dose in mg/8 gives the dose of lorazepam per day in mg 3.Give lorazepam in 4-6 divided doses 4.After 2 nd dose of lorazepam taper midazolam infusion by 50% 5.After 3 rd taper further by 50% 6.After 4 th dose of lorazepam stop midazolam infusion

25. Opioid withdrawal CNS- anxiety, irritability, trmors Gastrointestinal-nausea, vomiting, increased NG aspirates, diarrhea Autonomic dysfunction-tachycardia, tachypnea, hypertension, diaphoresis

26. / Weaning strategies- Conversion of IV morphine to oral- _mg/24 hr of IV multiplied by 3= _mg/24 hr of oral morphine given 4-6 th hrly Conversion of IV fentanyl to IV morphine- _ mcg/ 24 hrs iv fentanyl/1000 * 25= _mg/24 hr iv morphine in 4-6 divided doses To convert iv fentanyl to oral morphine first convert to iv morphine and then to oral morphine

27. Once oral morphine is added then start tapering by 20%(3-5 days) or 10%(>10days) every day until 0.2 mg/ dose is achieved. Increase the interval rather than decreasing the dose ie 4hrly-6hrly-8hrly-12hrly. Stop after 48hrs of 0.2mg 8 th hrly for infants and children and 0.2 mg 12 th hrly for neonates

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