Case 65 - Adenotonsillectomy Flashcards
what is the pathophysiology of OSA?
- during inspiration, diaphragm descends and chest wall expands to create negative intrathoracic pressure
- negative pressure transmits to lower and upper airways, which draws phayrngeal soft tissue into airway (obstruction)
- pharyngeal dilator muscles contract, the soft tissue moves out of the airway lumen and now airway is patent
How does tonsillar hypertrophy contribute to OSA?
tonsillar hypertrophy exacerbates upper airway obstruction 2 ways:
1) encroaches on airway and narrows cross-sectional area
2) bernoulli effect
- conservation of energy - low flow + high pressure = high flow + low pressure
- when cross-sectional area is reduced, airflow through stenosed pharynx increases, which reduces pressure inside pharynx (therefore pharynx unable to tent open airway)
What complications can OSA lead to?
Airway obstruction -> hypoxia and hypercarbia –> hypoxic pulm vasoconstrict –> pulm HTN –> RVH –> R atrial enlargment –> r sided CHF or cor pulmonale
how do you diagnose OSA?
Polysomnography
- hyponea - apnea index
- > 10 = severe OSA
- Hypopnea = > 50% decrease in airflow or desat
- apnea = > 90% decrease in airflow or desat
What pre-op evaluation will you perform for adenotonsillectomy?
1) Airway
- tonsillar size and craniofacial abnormalities
- conern = difficult mask ventilation and intubation
2) Pulmonary (if severe OSA pt)
- ABG –> Co2 retainer 2/2 to severe OSA
3) cardiac (if severe osa pt)
- cxr - cardiomegaly
- echo - cardiac function, pulm HTN
- ekg - right atrial enlargement, RVH
- consider cardiac consultatoin
4) heme
- bleeidng history
- if so, consider coag studies and PLT
- polycythemia if OSA pt
5) recent URI (w/i 2 weeks)
patient comes for AT and appears to have an upper respiratory infection. Are you concerned, does this change your management?
complications associated with URI:
- laryngospasm
- bronchospasm
- secretions clogging ETT –> prevent ventilation and oxygenation
- o2 desat in PACU
factors of URI that increase complications
- productive cough
- rhinorrhea
- appears very ill
- passive smoking (irritable airways)
- use of ETT
Delay or not delay
- ideally would postpone surgery for 3-4 weeks if elective
- may not be possible if recurring episodes of URI (may not have a window of opportunity)
- discuss risks of general anes to parents and document in record
Would you pre-med a child with OSA undergoing a AT?
- Avoid pre medication due to OSA and sensitivity to effects of sedatives
- if child is very anxious, judicious use of pre-med with continous pulse oximetry monitoring and emergency airway equpiment immedietely available.
What is your induction management for a patient coming for AT?
1) standard ASA monitors
2) if patient has severe OSA, place IV line pre-induction to allow for emergency meds if necessary
3) IV or inhalation induction
* place oral airway way deep to overcome airway obstruction from relaxed adenoid tissue
4) endotracheal intubation with a cuffed preformed tube (RAE, reinforced)
- ETT vs LMA
- ETT - protect against aspiration of blood
What is your intraop anesthesia maninteance management for a patient undergoing AT surgery?
1) inhaled anes, judicious use of opioid in OSA pts
- OSA pts sensitive to sedatives
- muscle relaxants not necessary
- may want to avoid in OSA patients as they can expereince muscle weakness despite antaognism of neuromsuclar blockade (remove variable if not necessary)
2) monitor airway pressure, breath sounds, capnography
* during procedure, mouth retractor, kinking, dislodgement of ETT into main stem or pharynx can occur
3) Post op analgesia
- tylenol
- judicious use of opioids. if spont vent, titrate to RR
4) PONV
- common during AT surgery
- decadron 0.5mg/kg (also helps with airway edema)
- ondansetron (0.1 mg/kg)
what is your emergence and extubation plan for patient undergoing AT?
1) reverse neuromusclar blockade if relaxants given
2) pass OG into stomach prior to emergence
* blood can accumulate in stomach
3) awake extubation
- full stomach due to debri and blood entering stomach (still at risk despite OG suction)
- awake, following commands, spont ventilation
Surgeon orders codeine for post-op pain management, what are your thoughts?
Codeine should not be given to children
- codeine metabolzes to morphine via liver
- genetic variation of Cyto P450 can lead to increase metabolism of codeine = greater fraction of morphine present in bloodstream
- has led to deaths
which patients should be admitted postop following AT sx?
For Apnea monitoring
- < 3 yo of age
- craniofacial abnormalities –> still at risk for obstruction
- neuromuscular abnormalities –> poor resp effort
How is patient with postadenotonsillectomy bleeding managed?
- bleeding following AT occurs in first 24 hours or, commonly 5-10 days post-op
- Urgent/emergent surgery depending on volume status
Preop Eval
- Airway assessment
- previous anesthetic
-
Volume status
- HR and BP
- IV or IO access
- fluid bolus if in shock
- Blood transfusion (based on CBC)
-
Labs
- H/H
- T&S
- Plt
- Coag studies
- determine if this is an emergent surgery
what is your intra-op anesthsia plan for postop bleeding AT patient?
1) If emergent surgery, do not wait for lab results
2) if hypovolemic based on H&P, fluid resuscitate STAT
3) Set up OR
- multiple laryngscope blades
- large bore suctions
- alternative airway devices
- tracheostomy equipment
4) RSI with cricoid
- full stomach due to blood pooled in stomach
- awake FOB may be difficult with blood in pharynx, and uncooperative pt
- if concerned about airway, maintain spont vent with inhaled induction, place pt head down to decrease risk of aspiration.
5) induction agents
- depends on volume status, prop vs ket vs etom
-
relaxant - SUX unles contraindicated
- fast on fast off (surgery may be quick)
6) transfuse based on coag,cbc, plt
