Airway Assessment
Predictors of difficult airway:
Mallampati classification (I–IV): Higher class indicates less visible oropharyngeal structures and potentially more difficult intubation
Thyromental distance less than 6 cm
Limited mouth opening (less than 3 cm)
Limited neck extension
Short thick neck
Obesity
History of difficult intubation
Facial trauma or pathology
Upper airway obstruction
Airway Devices
Natural airway maneuvers:
Head tilt-chin lift
Extends neck and lifts tongue from posterior pharynx
Jaw thrust
Displaces mandible anteriorly without neck extension; safer in cervical spine injury
Basic airway adjuncts:
Oral airway (Guedel)
Prevents tongue obstruction; sized from corner of mouth to angle of jaw; contraindicated if gag reflex present
Nasal airway (trumpet)
Better tolerated in semi-conscious patients; sized from tip of nose to tragus; avoid in basilar skull fracture and coagulopathy
Supraglottic airways:
Laryngeal mask airway (LMA)
Sits above glottis; does not protect against aspiration; various types including classic, ProSeal (gastric drainage channel), and intubating LMA
Other devices
i-gel, King airway
Endotracheal intubation:
Definitive airway; protects against aspiration
Confirms placement: Direct visualization, bilateral breath sounds, ETCO2 waveform (gold standard), chest X-ray
Common PACU Airway Problems
Airway obstruction:
Most common cause
Soft tissue (tongue) collapse due to residual anesthesia
Treatment
Jaw thrust, head positioning, oral/nasal airway, positive pressure ventilation
Laryngospasm:
Forceful, involuntary spasm of laryngeal muscles
Causes
Light anesthesia with airway stimulation (secretions, blood, suctioning)
Signs
Stridor progressing to complete obstruction (silent), paradoxical chest movement, desaturation
Treatment
Remove stimulus; 100% oxygen with positive pressure via tight mask seal; jaw thrust with "laryngospasm notch" pressure (behind earlobes, anterior to mastoid); deepen anesthesia if IV access; succinylcholine (0.1–1 mg/kg IV) if unresponsive to above measures
Bronchospasm:
Constriction of bronchial smooth muscle
Causes
Reactive airway disease, aspiration, irritation, allergic reaction
Signs
Wheezing, prolonged expiration, increased peak airway pressures, desaturation
Treatment
100% oxygen; deepen anesthesia; inhaled beta-agonists (albuterol); IV epinephrine if severe; corticosteroids; exclude other causes (endobronchial intubation, pneumothorax)
Aspiration:
Inhalation of gastric contents into tracheobronchial tree
Risk factors
Full stomach, emergency surgery, pregnancy, obesity, hiatal hernia, decreased consciousness, difficult airway
Prevention
NPO guidelines, rapid sequence induction, cricoid pressure (controversial)
Signs
Witnessed regurgitation, coughing, bronchospasm, hypoxemia, infiltrates on chest X-ray
Treatment
Suction oropharynx; intubate if not already; suction trachea; bronchoscopy if particulate matter; supportive care; antibiotics only if infection develops (not prophylactically)
Malignant Hyperthermia (MH)
A life-threatening pharmacogenetic disorder triggered by volatile anesthetics and succinylcholine in susceptible individuals. Genetic mutation affects ryanodine receptor causing uncontrolled calcium release from sarcoplasmic reticulum leading to sustained muscle contraction.
Signs (may appear intraoperatively or in PACU):
Early
Unexplained tachycardia, increased ETCO2, masseter muscle rigidity, tachypnea
Progressive
Rapid temperature rise (may increase 1–2°C every 5 minutes), generalized rigidity, mottled skin
Late
Hyperthermia (greater than 40°C), rhabdomyolysis, hyperkalemia, metabolic acidosis, myoglobinuria, disseminated intravascular coagulation, cardiac arrhythmias
Treatment:
Discontinue all triggers immediately
Hyperventilate with 100% oxygen
Dantrolene 2.5 mg/kg IV bolus, repeat every 5 minutes until symptoms resolve (may need 10+ mg/kg)
Active cooling
Cold IV fluids, ice packs to axillae/groin, cooling blanket (stop when temperature reaches 38°C to avoid overshoot)
Treat hyperkalemia
Calcium, bicarbonate, insulin/glucose, hyperventilation
Treat arrhythmias
Avoid calcium channel blockers (interact with dantrolene causing hyperkalemia and cardiovascular collapse)
Monitor urine output; maintain greater than 2 mL/kg/hr; consider mannitol for myoglobinuria
Send labs: ABG, electrolytes, creatine kinase, myoglobin, coagulation studies
Contact MH hotline: 1-800-644-9737
Post-crisis management:
Continue dantrolene 1 mg/kg every 4–6 hours for 24–48 hours
ICU admission for monitoring
Genetic counseling and referral for muscle biopsy testing
Postoperative Nausea and Vomiting (PONV)
Risk factors (Apfel score):
Female gender
History of PONV or motion sickness
Non-smoking status
Postoperative opioid use
Type of surgery: Strabismus, laparoscopic, gynecologic, cholecystectomy, middle ear
Prevention strategies based on risk:
Low risk (0–1 factors)
No prophylaxis needed
Moderate risk (2 factors)
Single antiemetic
High risk (3–4 factors)
Multimodal prophylaxis; consider total IV anesthesia (TIVA)
Antiemetic medications:
Serotonin (5-HT3) antagonists
Ondansetron 4 mg IV; can cause QT prolongation and headache
Corticosteroids
Dexamethasone 4–8 mg IV; give at induction for maximum effect
Dopamine antagonists
Droperidol 0.625–1.25 mg IV; black box warning for QT prolongation; metoclopramide 10 mg IV
Anticholinergics
Scopolamine transdermal patch; apply evening before or morning of surgery
Antihistamines
Diphenhydramine 25–50 mg IV; promethazine 12.5–25 mg IV
NK-1 receptor antagonists
Aprepitant (oral); effective for delayed PONV
PACU treatment of established PONV:
Use antiemetic from different class than prophylaxis
Address contributing factors: Pain control, hypotension, movement, early oral intake
Ensure adequate hydration
Emergence Delirium/Agitation
Acute confusion and agitation during emergence from anesthesia.
Risk factors: Extremes of age (pediatric and elderly), preoperative anxiety, pain, hypoxemia, hypercapnia, hypoglycemia, full bladder, hypothermia, ketamine or benzodiazepine administration, prolonged surgery, alcohol or drug withdrawal
Assessment:
Rule out physiological causes first (hypoxemia, hypercapnia, hypoglycemia, hypotension)
Ensure adequate pain control
Check for urinary retention
Management:
Maintain safety (padding, restraints if necessary)
Calm, reassuring environment
Treat underlying cause
Pharmacological: Propofol 10–20 mg IV boluses; dexmedetomidine; benzodiazepines for alcohol withdrawal
