Steps of extubation in general anesthesia patients

Proper method of extubation with adequate reversal

1. Extubation

2. Weaning : is the transition from ventilatory support to completely spontaneous breathing . SBT : spontaneous breathing trial is a period of breathing without ventilatory assistance or with minimal ventilatory support ( on CPAP or low level of pressure support ) Extubation is the removal of the artificial airway . Extubation can be of two types : - Planned extubation - Unplanned extubation

3. Planned extubation Removal of the ET tube or any artificial airway by the clinician. Criteria for extubation : Hemodynamically stable : no dysarrythmias , minimal inotrope requirements, optimal fluid balance Adequate ventilation & oxygenation : - spO2 > 92 percent - vital capacity > 10 ml / kg - tidal volume > 5 ml/ kg - respiratory rate < 25bpm Arterial blood gas : -pH is normal - pCO2 < 60 mmHg - pO2 > 60 mmHg on FIO2 of 0.4 and PEEP 5 Full Reversal of Muscle relaxation: - TOF > 0.9 - sustained 5 second head lift Or hand grasp Neurologically intact : awake , follows verbal commands & intact gag / cough reflex

4. SAD REMOVAL Should be left in place until the patient has recovered full ventilatory capacity & regained consciousness. At the point of return of consciousness, airway reflexes are also recovering & patient will normally protect their own airway. A better way to asses consciousness is to see the response to voice , making spontaneous movements towards the SAD or following commands . Suction should be used to clear the oropharynx of secretions , the patient should be asked to open the mouth and the SAD should be removed . The need to deflate cuff varies with SAD but as for LMAs , retaining some air in the cuff will assist in clearing secretions . After removing the SAD , O2 should be administered by mask or nasal canulae & respiration should be moni tored.

5. TRACHEAL TUBE REMOVAL TRACHEAL TUBE maybe removed when : - patient is unconscious. - patient is awake Deep tracheal extubation is a higher risk procedure & should be reserved for very low risk patients. Awake tracheal extubation is generally preferred unless the stimulus will have a negative impact on the patient’s physiology.

6. ‘ At risk ‘ for Extubation Patients who had problems at induction or intubation. Blood in the airway from surgical or anesthetic causes . Patients who may have airway edema from anaesthetic or surgical interventions. Obese patients particularly those with OSA Intraoral / airway Surgery

7. Special procedures These are non – routine actions at tracheal extubation performed to improve the safety of extubation & to facilitate re – intubation if necessary. Certain examples are : - Insertion of a cricothyroid needle or AEC ( Airway exchange catheter ) before extubation - exchange of the tracheal tube for a SAD immediately before or after tracheal extubation ( Bailey’s manoeuver ) - tracheal extubation followed by CPAP or high flow nasal oxygen

8. COMPLICATIONS A. Immediately after extubation : Aspiration / regurgitation : are increased in all patients at high risk & by airway removal in the light plane of anaesthesia before full wakefulness . If a nasogastric tube is present , this should be auctioned before airway removal.

9. 2. Laryngeal spasm / Bronchospasm / coughing : are all likely to occur in those with an irritable airway eg : smokers, patients with asthma , patients with current or recent respiratory tract infection. Laryngospasm occurs as a result of extubation when the patient is semiconscious . Extubation during this excitement stage tends to stimulate the vocal cords & lead to reflex protective spasm. For this reason extubation should be done when patient is either deeply anaesthesised or fully awake. In worst scenario airway obstruction occur and reintubation is needed.

10. 3. Hoarseness 4. Laryngeal or subglottic edema : stridor is seen . Cuff leak test : Done to asses laryngeal swelling & is very much dependent on the size of tracheal tube used , in this test the tracheal tube cuff is deflated and postive pressure is applied while listening for an audible leak around the trachea . For this we can use a cool aerosol & 0.25 – 0.5 ml of 2- 2.5 percent racemic epinephrine in 5 ml of saline may be helpful. Dexamethasone at 0.15 mg /kg may help prevent worsening of edema .

11. B . Following extubation : Mucosal injuries Laryngeal stenosis Tracheal inflammation, dilation, stenosis Vocal cord paralysis

12. Neostigmine A ppropriate neostigmine reversal is defined as “neostigmine ≤60 μ g/kg given at a TOF count of ≥2”   It does require the simultaneous use of an anticholinergic agent such as glycopyrrolate or atropine to prevent its muscarinic effects including bradycardia, bronchospasm, and increased intestinal motility. It is only efficacious if : - recovery from neuromuscular block has commenced: at least two twitches of the train-of-four (TOF) response should be detectable before it is given. - It also takes at least 8 min to have its maximum effect -  Neostigmine has a ceiling effect: increasing its dose does not necessarily increase its efficacy, which is a limitation of its use. It may also cause depolarising block if given in excess. It is excreted in the urine and hence has a prolonged muscarinic effect in patients with renal insufficiency. Allergic reaction to neostigmine is very rare.

13. RESIDUAL NEUROMUSCULAR BLOCK Inadequate recovery from neuromuscular block with a TOFR less than 0.9 in the postoperative recovery room occurs in up to 45% of patients receiving neuromuscular blocking drugs during anaesthesia. There is increasing evidence of an association between inadequate recovery from neuromuscular block and respiratory complications in the immediate recovery period, such as : arterial desaturation, obstruction of the upper airway, need for reintubation , and pulmonary aspiration.

14. Clinical features : In ability to perform a : head lift, hand grip, eye opening, or tongue protrusion; inability to clench a tongue depressor between the incisor teeth; inability to smile, swallow, speak, cough, track objects with eyes B lurry vision, diplopia, facial weakness, facial numbness, and general weakness.

15. Impaired hypoxic respiratory drive and even unexpected admission to the ICU may also ensue. Recovery from neuromuscular block should always be monitored at the end of anaesthesia using a quantitative monitor that gives a recording of the TOFR. Full recovery of the TOFR to more than 0.9 at tracheal extubation is less common after neostigmine than after sugammadex . This results in fewer immediate respiratory complications if sugammadex is used.

16. EXTUBATION IN ICU Extubation is decided after a weaning readiness test is a formal trial of spontaneous breathing to evaluate readiness for discontinuation of the endotracheal tube and /or ventilatory support . This is evaluated on a CPAP or T – piece . Others : - sedating agents must be stopped for > 24 hours - causative condition resolved / under control - paralysing agents stopped > 24 hours - normal metabolic status . Electrolytes balance must be normal. - patient must be neurologically intact. - take into consideration of aspiration risk & airway edema ..

17. EXTUBATION FAILURE It is defined as the need for reinstitution of ventilatory support within 24 – 72 hours of planned endotracheal tube removal, occurs in 2 – 25 percent of extubated patients. Occurs due to imbalance between respiratory muscle capacity & work of breathing, upper airway obstruction, excess respiratory secretions, inadequate cough , encephalopathy & cardiac dysfunction. Risk factors : - Age > 70 years. - longer duration of mechanical ventilation - continuous IV sedation. - anemia Preventive measures are : - non – invasive ventilation after extubation in high risk or hypercapnic patients . - steroid administration several hours before extubation .

18. UNPLANNED EXTUBATION Deliberate or accidental removal of the ET tube by the patient. Inadvertent extubation occurs in 8 – 10 percent of all extubation in ICU patients. About 50 percent do not need a reintubation . Whether or not to reintubate the patient can be a difficult decision. Delayed reintubation may lead to : - hypoventilation - hypoxemia - hypoxia In general decision to reintubate depends on clinical observations & criteria for Extubation : - rapid shallow breathing index ( RSBI ) - blood gases - ventilatory reserve - general cardiopulmonary signs

19. EXTUBATION IN CHILDREN

20. Awake extubation is considered in : Difficult mask ventilation Difficult tracheal intubation High risk of difficult reintubation Case of high risk of aspiration Patients at risk for inadequate ventilation once extubated like : - infants with prematurity or small size ( < 2 kg ) - obese patients - patients with sleep disoriented breathing

21. Intubation is a skill but extubation is an art.... Thank you