Overview from standard sources miller, morgan with reference of pediatric anesthesia, viva ty0e during a case of pediatric anesthesia for adenoyonsillectomy

Reading File

Finding Sources

Reading File

I now have rich content from Miller's, Barash (Stoelting), and Morgan & Mikhail. Let me compile the comprehensive viva-style overview.

Pediatric Anesthesia for Adenotonsillectomy: Viva Overview

Sources: Miller's Anesthesia 10e, Morgan & Mikhail's Clinical Anesthesiology 7e, Barash/Stoelting's Clinical Anesthesia 9e

1. INDICATIONS FOR ADENOTONSILLECTOMY

Q: What are the indications for adenotonsillectomy in children?

Recurrent/chronic tonsillitis (most common) - typically defined as >7 episodes/year or >5/year for 2 consecutive years
Peritonsillar abscess
Tonsillar/adenoidal hyperplasia with airway obstruction
Obstructive Sleep Apnea Syndrome (OSAS) - most important anesthetic concern
Failure to thrive, speech disorders, dental abnormalities from chronic obstruction
Cardiac valvular disease with recurrent streptococcal bacteremia
Malignant disease (lymphoma - important caveat for dexamethasone use)

(Barash 9e, p.4079)

2. PREOPERATIVE EVALUATION - KEY VIVA POINTS

Q: What is your preoperative focus for this child?

A - Airway assessment:

Size of tonsils and adenoids
Degree of nasopharyngeal obstruction
Mouth opening, neck mobility

B - Screen for OSAS:

Snoring, witnessed apneas, restless sleep, daytime somnolence, nocturnal enuresis, behavioral changes
The "gold standard" is polysomnography (PSG)
Apnea-Hypopnea Index (AHI): severe OSA = AHI >10 AND oxygen saturation nadir <80%
Barash: "Despite only mild-to-moderate tonsillar enlargement, these patients have upper airway obstruction while awake and apnea during sleep - do not underestimate severity based on tonsillar size alone"

C - Cardiac comorbidities from chronic OSAS:

Cor pulmonale - right ventricular hypertrophy, cardiomegaly
Pulmonary hypertension, systemic hypertension
ECG for RVH; CXR for cardiomegaly
Each apneic episode spikes pulmonary artery pressure further

D - Recent URTI:

Active fever or productive cough = grounds for postponement
Recent URTI within 2-4 weeks increases risk of laryngospasm, bronchospasm

E - Coagulation status:

History of bleeding, family bleeding history
Platelet count, clotting screen if indicated

F - Obesity:

Obese children: especially high risk for OSA, opioid sensitivity, respiratory arrest post-op (Miller 10e, Morgan 7e, Barash 9e)

3. PEDIATRIC AIRWAY - ANATOMICAL DIFFERENCES (VIVA FAVORITE)

Q: How is the pediatric airway different from adult?

Feature	Pediatric	Clinical Implication
Head	Proportionately larger	Sniffing position - less neck extension needed
Tongue	Larger relative to oral cavity	Higher risk of obstruction
Larynx	Anterior and cephalad (C3-C4 vs C4-C5 in adult)	More anterior - view can be difficult
Epiglottis	Longer, floppy, U-shaped	Use straight blade (Miller) for better lift
Narrowest point	Cricoid ring (<5 years) vs glottis in adults	Uncuffed tube may leak; cuffed tubes now safe if chosen correctly
Trachea	Shorter	Higher risk of endobronchial intubation
Nasal breathers	Until ~5 months	Obligate nasal breathers - blocked nose = respiratory distress
FRC	Reduced (chest wall very compliant)	Rapid desaturation during apnea

(Morgan & Mikhail 7e, p.1671; Barash 9e)

Q: What is the formula for uncuffed ETT size?

(Age/4) + 4 for uncuffed; (Age/4) + 3.5 for cuffed
Confirm with air leak at 15-20 cmH2O (uncuffed) or cuff pressure <20 cmH2O

4. ANESTHETIC INDUCTION

Q: How would you induce anesthesia?

Inhalational induction (preferred in children):

Sevoflurane is the agent of choice - greater therapeutic index than halothane
MAC of sevoflurane is highest in infants (2.5%) vs adults (2.0%)
Inhalational induction followed by IV cannulation
Glycopyrrolate 10 mcg/kg IV after IV access - reduces secretions, attenuates bradycardia

IV induction (if IV access present or older child):

Propofol 3-4 mg/kg + fentanyl 1-2 mcg/kg
Ketamine useful if haemodynamically compromised

Q: What is important about MAC in pediatric patients?

MAC is highest in infants (not neonates), decreasing with age
Exception: sevoflurane MAC shows no difference between neonates and infants
Physiological reason: higher alveolar ventilation/FRC ratio, greater cardiac output to vessel-rich group = faster wash-in of volatile agents (Morgan & Mikhail 7e)

5. AIRWAY DEVICE

Q: ETT or LMA for adenotonsillectomy?

Options:

Oral RAE (Ring-Adair-Elwyn) preformed ETT - most commonly used; taped in the midline to mandible; keeps tube out of surgical field; risk of kinking with mouth gag
Wire-reinforced (armored) ETT - resistant to kinking
Flexible LMA - used in some centers; kinking/displacement with Boyle-Davis gag is a concern; requires experienced team; advantage of avoiding laryngoscopy

Key points:

Tube taped in midline of mandible (not corner of mouth)
After gag placement: always recheck tube position - kinking or displacement is not uncommon
ETT cuff inflation pressure must be checked after position change (neck extension for surgery)
Throat pack placement by surgeon - mandatory documentation, must be removed before extubation (Miller 10e, p.9812; Barash 9e)

6. MAINTENANCE OF ANESTHESIA

Q: What agents do you use for maintenance?

Either volatile (sevoflurane/isoflurane) or TIVA (propofol infusion) - both acceptable
TIVA preferred by some due to reduced PONV, no theatre pollution, cleaner emergence
Opioids: Fentanyl or morphine (use cautiously in OSA - reduce dose by up to 50%)
Dexamethasone 0.15-0.5 mg/kg IV: reduces PONV, reduces postoperative swelling, improves oral intake
- CONTRAINDICATED if lymphoma is suspected - may cause lethal hyperkalemia from tumor lysis
NSAIDs (e.g., ketorolac, ibuprofen): good evidence for analgesia without increased bleeding risk, though some surgeons avoid
Paracetamol/acetaminophen: inadequate alone for tonsillectomy pain
Ondansetron for PONV prophylaxis
Local anaesthetic infiltration to tonsillar bed (with or without epinephrine) by surgeon - caution: injection into tonsillar vessels beneath tonsillar bed can cause seizures or cerebral infarction (Miller 10e; Barash 9e, p.10647)

Q: Why avoid NSAIDs in some centers?

Theoretical concern about platelet dysfunction and post-tonsillectomy haemorrhage
Evidence: bleeding rate NOT significantly increased with NSAIDs; most guidelines support their use
Individual surgeon/institutional preference governs

7. OSA AND OPIOID SENSITIVITY - CRITICAL VIVA POINT

Q: Why are OSA children sensitive to opioids?

Chronic intermittent hypoxemia upregulates central opioid receptors
Altered CO2 response curves - blunted hypercapnic drive
Risk of post-op respiratory arrest even with standard doses
Reduce opioid dose by up to 50% in OSA patients (Barash 9e, Key Point 3)
Maximize non-opioid multimodal analgesia

8. EXTUBATION - DEEP vs. AWAKE

Q: When do you extubate - deep or awake?

Awake extubation (more common, safer overall):

Patient regains protective airway reflexes
Reduces risk of airway obstruction post-extubation
Risk: coughing/bucking on tube may trigger bleeding from surgical site

Deep extubation:

Smoother emergence, less coughing/straining
Reduces bleeding risk from Valsalva-like maneuvers
Risk: airway obstruction - must be managed in high-dependency environment
Only appropriate if very experienced team and environment capable of rapid detection/management of obstruction

Adjuncts for smooth emergence (awake route):

Lignocaine (lidocaine) 1.5 mg/kg IV or topical down ETT (cuff deflated)
Light remifentanil infusion during emergence
Suction oropharynx thoroughly + remove throat pack before extubation
Pass orogastric tube to decompress stomach (swallowed blood/secretions) (Miller 10e, p.9812)

9. COMPLICATIONS

A. Post-Tonsillectomy Haemorrhage (PTH) - MOST FEARED COMPLICATION

Q: How do you manage a child with post-tonsillectomy haemorrhage?

Primary (within 6 hours): often from inadequate surgical haemostasis Secondary (days 5-10): usually infective sloughing of eschar

Anaesthetic management - key principles:

Volume resuscitate first - IV access, fluids, blood if needed; hypovolemia reduces induction drug requirement - consider etomidate
Treat as full stomach - significant swallowed blood in stomach
Rapid sequence induction (RSI) with cricoid pressure - mandatory
Prepare for difficult airway - bleeding + swelling + anxious child = previously easy laryngoscopy can quickly become impossible
- Have multiple laryngoscope sizes/blades available
- Videolaryngoscope on standby
- Have smaller ETT sizes ready
- Vigorous suction needed during laryngoscopy
Surgeon must be present and scrubbed before induction

(Miller 10e, p.9812; Barash 9e, Key Point 4)

B. Laryngospasm

Most common airway complication in pediatric anesthesia
Risk factors: light anesthesia, secretions/blood, recent URTI
Treatment: CPAP, jaw thrust, deepen anesthesia (propofol 0.5-1 mg/kg), suxamethonium 1-2 mg/kg IV (or 4 mg/kg IM) if complete

C. Negative Pressure Pulmonary Edema (NPPE)

Occurs after sudden relief of chronic upper airway obstruction
Mechanism: high negative intrapleural pressures (-30 cmH2O in obstruction vs. -10 cmH2O normally) increase venous return and disrupt pulmonary microvasculature
Frothy pink fluid in ETT, SpO2 drop, bilateral interstitial infiltrates on CXR
Prevention: apply moderate CPAP during induction to allow circulatory adaptation
Treatment: supportive - oxygen, CPAP/PEEP, diuretics; usually resolves within 24 hours (Barash 9e, p.4094-4095)

D. Post-operative Nausea & Vomiting (PONV)

Very common - multimodal prophylaxis essential
Dexamethasone + ondansetron + TIVA where possible

E. Airway Obstruction Post-extubation

Especially with residual tonsillar tissue, edema, or in OSA children
Lateral "tonsil position" (lateral decubitus) for recovery

10. OSA - POSTOPERATIVE DISPOSITION

Q: Who needs overnight admission after adenotonsillectomy?

Admit to hospital (Barash Table 48-1) if ANY of:

Age <3 years
Severe OSA (AHI >10, SpO2 nadir <80%)
Cor pulmonale / cardiac abnormality
Failure to thrive / poor oral intake
Craniofacial abnormality
Neuromuscular disorder
Obesity (BMI >95th percentile)
Sickle cell disease
Post-op SpO2 <80% in recovery
Bleeding concerns
Lives far from hospital / no reliable carer

Day-surgery discharge criteria: no active bleeding, PONV controlled, adequate analgesia, adequate oral intake of fluids, SpO2 acceptable on room air for >1 hour, appropriate carer/distance.

11. PHARMACOLOGY REMINDERS (VIVA SPECIFICS)

Drug	Dose	Notes
Sevoflurane MAC	~2.5% (infant)	Higher than adult (2.0%)
Propofol induction	3-4 mg/kg	Reduce in OSA/hypovolemia
Fentanyl	1-2 mcg/kg	Reduce 50% in OSA
Dexamethasone	0.15-0.5 mg/kg (max 8mg)	Avoid if lymphoma suspected
Ondansetron	0.1 mg/kg (max 4mg)	PONV prophylaxis
Glycopyrrolate	10 mcg/kg	Anti-sialagogue, attenuates bradycardia
Suxamethonium (laryngospasm)	1-2 mg/kg IV; 4 mg/kg IM	Beware bradycardia in children
Lignocaine (smooth emergence)	1.5 mg/kg IV	Or topical via deflated cuff

12. SURGICAL SETUP - VIVA POINTS

Position: supine, head ring, neck extended (shoulder roll)
Mouth gag: Boyle-Davis gag - risk of ETT/LMA displacement, kinking; ALWAYS recheck after placement
Throat pack: surgeon places; anaesthetist must document and ensure removal before extubation ("count" system)
Shared airway: requires constant communication between surgeon and anaesthetist

SUMMARY ALGORITHM FOR THE CASE

Pre-op: Screen for OSA severity → Echo/ECG if cor pulmonale → Check coags → Postpone if active URTI/fever
Induction: Inhaled sevoflurane → IV access → glycopyrrolate → RSI if full stomach/PTH
Airway: Oral RAE ETT (midline taped) or flexible LMA
Maintenance: Volatile or TIVA + reduced-dose opioids (OSA) + dexamethasone + paracetamol + NSAID
Intraop: Check ETT after gag placement; monitor EtCO2, SpO2, temp
End of case: Remove throat pack + suction oropharynx + OGT to empty stomach
Extubation: Awake preferred; deep only if skilled team; lateral recovery position
Post-op: Multimodal analgesia; PONV prophylaxis; admit if OSA criteria met
Complication readiness: PTH → RSI protocol; Laryngospasm → sux protocol; NPPE → CPAP/PEEP

References:

Miller's Anesthesia 10e, Ch. 27 & 29 - Tonsillectomy and Adenoidectomy
Morgan & Mikhail's Clinical Anesthesiology 7e, Ch. 54 - Pediatric Anesthesia
Barash/Stoelting's Clinical Anesthesia 9e, Ch. 48 - Anesthesia for Pediatric ENT Surgery

This is a shared conversation. Sign in to Orris to start your own chat.