Emergence & Extubation Flashcards
Definition of emergence
Awakening from the effects of an anesthetic drug. CNS is waking up, much less predictable than induction, now will see stage 2 of excitation. Neurotransmitter “Orexin” involved in arousal.
Goals of E&E
Stable vitals / spontaneous respiration / ability to protect airway / alertness/purposeful/responsive / normal NM function.
Complications of Emergence
Delirium / unstable vitals (tachycardia, HTN) / delayed emergence / poor/dysfxnl resp effort / residual paralysis / diffusion hypoxia
How to promote emergence:
Halting admin of anesthetic in appropriate time, don’t wake up while paralyzed. May need reversal agent or more time (no reversal for volatile, allow time to blow off). Maintain some level of analgesia.
Definition of Delayed Emergence:
failure of pt to regain expected LOC w/i 20-30 min of end of anesthetic. Must think through diff Dx. Pt usually wake up w/i 5-10 minutes. Checking pt hx and timing of last dosing.
What Populations are at greatest risk for delayed emergence?
Pts rec sedative meds / cognitive/psych disease / intoxication @ anesthetic / physical exhaustion @ anesthetic / ? narcoleptics ? / elderly
R/O ALOC/delayed emergence diagnoses
1 - hypoxia! #2 - airway obstruction #3 - hypercarbia #4 - hypothermia
What is proper evaluation of delayed emergence?
Evaluate: Patient history –> Review meds administered –> Consider Sx/Anesth complications –> assessment of vitals (hypothermia)
Categorical causes of delayed emergence
Anesthetic drugs / medications / electrolyte disorder / metabolic disorder / systemic effects
Delayed Emergence Causes: Anesthetic Rx
CNS sensitivity / drug clearance altered by hepatic/renal disease / elevated free frxn of rx d/t low albumin –> Tx’s = improve ventilation, reversal agents, allow time
Reversal agents/doses
Naloxone: 40cmg q2 min up to 200mcg / Flumazenil 0.2mg up to 1mg / physiostigmine 1.25mg (raise orexin levels?)
Delayed Emergence Causes: Electrolyte Disorder
Hyponatremia = lethargy, Sz, cerebral edema / Hypercalcemia/Hypermagnesemia = mild to severe CNS depression
Delayed Emergence Causes: Metabolic Disorder
Hyperglycemia = hyperosmolar coma / hypoglycemia = sz, etc / hypothyroid/adrenal deficit = poss coma
Delayed Emergence Causes: Systemic Effects
Hypercarbia / Cerebral Vasc event/stroke / Seizure / hypothermia (threshold around 36*C)
Delayed Emergence Causes: Dysfunctional Respiration/Apnea
Residual NM blockage = nerve stim / narcotic effect = last dose? reversal / Blunted hypoxic drive = chronic retention, lower FiO2 / hypocarbia = too low to stim resp drive, hypovent pt / CNS injury = brain swelling alter resp centers
Timing of extubation
Prior to emergence (stage 3) or when patient awake/alert (stage 1). Never extubate while in pt is “light” aka delirium/excitation (stage 2)
Characteristics of Stage 2
CV instability / dysconjugate eye mvmts / retching/emesis / breath holding / exaggerated responses to stimuli / not coop or alert
Deep Extubation: advantages/disadvantages
Adv: less coughing (ideal for plastics, head/neck, eye and Nsurgery), attenuated HD response, decr bronchospasm risk
DisAdv: AW obstruction, aspiration, laryngospasm RSI or DIff AW = no deep exbation
Awake Extubation: Neuro parameters
Adequate NM fxn (no fade, sust tetany, 5 sec head lift), LOC stable, Stage 1, awake, purposeful, following commands
Awake Extubation: Pulm parameters
NL ABG/SpO2 on 40%, RR 10-30, Vt/RR >10, NIF -20-30 cm water, VC > 10-1ml/kg, Vt > 5ml/kg, no evidence of v/q mismatch
Awake Extubation: Misc parameters
HD stable, normothermia, NL labs, acceptable pain control
Equipment Trick/process for extubation
100%, close pop off valve a little, suxn trach/oral cavity as needed, hyperinflate to create mandatory exhale upon tube removal, place oral AW
Extubation complications
1 is obstruction / AW relaxation, edema / hematoma / laryngospasm (stage 2) / vocal cord dysfxn / Foreign body(aspiration)
Extubation complications: Larygnospasm
D/T stage 2 extubation, light with hyperactive reflexes, presence of secretions. Tx with pos pressure, lidocaine, small dose of succinylcholine. Possibly causing neg press pulmo edema.
Extubation complications: edema
usually tongue is culprit, croup in pediatrics. Prone position, long case, excess fluid volumes create glossal edema. Tx w/ cool mist, racaemic epi. Can check with cuff leak test.
Extubation complications: hematoma
Poss life threatening situation, swelling may compl occlude AW. Must evac hematoma prior to att re-intubation.
Extubation complications: Vocal cord dysfunction
Poss paralysis d/t recurrent laryngeal nerve damage. Creates passive vocal cord closure, varying degrees of AW blockage, depends on unilateral vs bilateral.
Extubation complications: non AW complications
tachycardia, HTN, coughing/bucking , aspiration, bronchospasm.
Extubation complications: tachycardia/HTN
Common occurence, worrisome w/ CAD, NeuroVasc disease patients. 10-30% transient increase in numbers. Tx with lido, esmolol, NTG
Extubation complications: Coughing/bucking
Increased intrathoracic, intracranial, intraocular pressures. Increase tension on surgical sites/incisions/sutures. Tx with narcotics, Lidocaine via LTA, IV lido prior to extubation.
Extubation complications: Bronchospasm
Provoked by light anesthesia as ETT is mechanical irritant. Use beta agonists, LMA. Asthmatics think LMA, bronchodilators, heavy gas. Rept albuterol prior to emergence. Poss deep exchange of ETT for LMA.
Extubation complications: Extubation with LMA
Less stimulating than ETT, less side effects, tachy/htn/bucking/bronchospasm. Remove when pt awake, squeeges AW clean, use with bite block for removal. Usually a smoother wake up.
Extubation complications: Diff AW extubation
Awake extubation, careful eval of clinical conditions prior to removal, have back up plans. Want aspiration, obstruction risks removed/decreased with pt being awake, coop, + reflexes, NM intact with good resp effort.
