Intubation and Extubation

This section will discuss how an ideal intubation will work; in emergent situations this process may differ.

Indications

• Respiratory failure – hypoxic and/or hypercapnic.
• Respiratory distress – angioedema or anaphylaxis with impending airway compromise, pending ventilatory failure due to exhaustion.
• Airway protection – altered mental status that is not expected to be short-lived (NICO trial) without ability protect airway (prevent aspiration and clear secretions); GCS <8.
• Airway trauma – damage or penetrating injuries to larynx.

Contraindications

• Airway trauma/obstruction preventing safe placement of ETT; if definitive airway is needed, consider tracheostomy/cricothyrotomy.
• Not within goals of care - confirm code status.

Considerations

• Will the patient be able to be extubated? Is the underlying cause necessitating intubation treatable/reversible? Would a tracheostomy be within their goals of care?
• Is the intubation high risk? Difficult airway anatomy, physiologic instability, and underlying comorbidities (pulmonary hypertension) increase the chance for further decompensation with intubation.

**If overnight, Airway team must be called. Call Airway Phone: (615) 887-7369.

• Provides direct contact with the on-call resident/Airway Team (they also respond to all overhead STATs for airway management).
• Utilized during MICU night shifts or when the MICU attending is unavailable.
• If the Airway Team is consulted for intubation, the anesthesia attending and residents will perform the induction and intubation – other team members are not permitted to intubate under these circumstances per Anesthesiology Department protocol.

Checklist

• Assess the patient:
  • Airway predictors for difficult intubation: Mallampati ≥ III, neck circumference > 40 cm, thyromental distance < 6cm, head-neck extension <30˚, mouth unable to open > 34cm.
  • High risk comorbidities: pulmonary hypertension with RV failure, angioedema, variceal hemorrhage, hemodynamic instability.
• Prepare the patient
  • Two large bore IVs
  • Position in the supine sniffing position, pre-oxygenate with 100% FiO2 and NIV if patient not actively vomiting.
• Prepare the equipment
  • Monitoring: SpO2, end-tidal CO2 monitor (capnography), continuous BP cycling, telemetry.
  • Airway: Bag-valve mask, 2 endotracheal tubes (check cuffs prior to utilization), direct laryngoscope, video laryngoscope, bougie/stylet, suction device (on and functional), supraglottic and oropharyngeal airway as backup.
• Prepare the medications:
  • Paralytic (succinylcholine or rocuronium), sedative - induction (etomidate or ketamine) and maintenance (propofol), analgesic for intubation (fentanyl).
  • Should have fluids, pressors, inotropes hanging in the room.
• Prepare the team:
  • First and second intubators, RT, RN to prepare meds, RN to give meds, someone to monitor hemodynamics, someone with hand on the pulse.
  • Run through the plan: meds to be given, meds available as backup.

Rapid-sequence intubation (RSI)

• Simultaneous administration of a sedative and paralytic to reduce patient movement and airway reflexes and quickly achieve optimal intubation conditions.
• Goal is to intubate within 60 seconds of paralysis onset.
• Preferred method of induction; associated with increased first-attempt success, reduced aspiration risk, reduced gastric insufflation, and even improved extubation rates.

Post-intubation

• Ensure correct ETT placement: End-tidal CO2 color change (gold standard), bilateral breath sounds, and chest rise, absence of gastric sounds, CXR.
• Secure the ETT with tape and/or tube holder.

Complications

• Airway trauma (oropharyngeal, laryngeal/vocal cords).
• Aspiration: Suction airway (ideally prior to initiation of PPV).
• Desaturation/Hypoxia: Caused by inadequate preoxygenation, PTX, mucous plugging. Rescue maneuvers with bag-mask ventilation if necessary. Stat CXR.
• Hypercapnia: Assess for cuff leaks - if underinflated or defective can lead to poor ventilation.
• Cardiovascular collapse: intubation increases intrathoracic pressure and thus decreases venous return and CO; sedation vasodilates and decreases BP, sympathetic surge may trigger arrhythmia leading to cardiogenic shock. Manage with fluids/pressors if need, rule out other causes (ex: hypoxia, PTX).
• Mechanical injury: Dental, soft tissue, tracheal, laryngeal. Retrieve any dislodged teeth, suction blood.

Assessing patients for extubation readiness

• Patients should be assessed for extubation readiness daily with SAT/SBT trials.
• Spontaneous Awakening Trial (SAT)
  • Contraindication: seizures, alcohol withdrawal, agitation, paralytics, MI, or increased ICP.
  • Pass: Patient is able to follow commands without significant anxiety, agitation, or respiratory distress as evidenced by vital signs. Dexmedetomidine can be used if having trouble with agitation or anxiety.
  • Fail: Unable to cooperate/follow commands, clinically significant VS changes (new or worsening arrhythmia, tachypnea, hypoxia).
  • If failed, restart sedation at reduced dose and titrate to RASS 0 (unless otherwise specified).
• Spontaneous Breathing Trial (SBT)
  • Once SAT is passed
  • Trial of pressure support (PS); PEEP ≤7.5cm H2O and FiO2 ≤ 50% for at least 30 minutes (ideal settings: PS 5cm H2O and PEEP 5cm H2O with FiO2 40%).
  • Pass: No evidence of respiratory distress (tachypnea, bradypnea, hypoxia).
  • Fail: Tachypnea (RR>35), bradypnea (RR <8), hypoxia (O2 sat < 88%), respiratory distress, cardiac arrhythmia, worsening hypotension; new hypertension or marked/increased tachycardia (demonstrates increased work to maintain adequate breathing on SBT).

Additional considerations prior to extubation

• Has the underlying cause of their respiratory failure or need to be intubated improved?
• Is the patient able to protect their airway (coughing) and handle secretions?
• What does the patient need to be extubated to? (RA, LFNC, BiPAP)
  • Preventative post-extubation BiPAP not routinely used in all pts but consider in select populations at high risk for failure: severe COPD with preexisting chronic hypercarbia, cardiogenic pulmonary edema, NMD, baseline supplemental oxygen or NIPPV use.
• Is there a cuff leak, or lack thereof which will require pretreatment with steroids?
  • Cuff leak test: Set ventilator to AC/VC and measure the TV. Deflate the ETT cuff completely, observe for an audible leak, and measure the difference in TV between delivered and exhaled breaths over 6 breathing cycles. Average the 3 lowest expiratory TV values.
    • Positive cuff leak: can hear audible leak, TV difference of >110-130 mL or > 10% between delivered and exhaled breath; significant variability in criteria.
    • A negative cuff leak test (lack of cuff leak) is not very accurate, but can indicate possible laryngeal edema and post-extubation airway obstruction/stridor.
  • Negative cuff leak is not an absolute CI contraindication to extubation. May require steroids to minimize airway swelling.
    • IV Solumedrol 20 mg IV Q4hrs for 4 doses prior to extubation.
  • For borderline cases, calculate a Rapid Shallow Breathing Index (RSBI):
    • RR/TV (in liters) during their SBT or while on PS.
    • RSBI > 105 is indicative of higher likelihood of reintubation; higher score = greater risk.

Post-extubation

• Consider ABG/VBG 20-30 mins after extubation to ensure adequate ventilation.
• Airway clearance therapy should be available for patients with NMD, COPD/bronchiectasis, and those with heavy secretion burdens.
• Extubating to BiPAP as described above has data supporting its use in certain scenarios such as in patients with known hypercapnia.

Complications

• Laryngeal Edema/Stridor: Can occur even if positive cuff leak.
  • Risk factors: Prolonged intubation ≥7 days, large ETT, repeated or traumatic intubation attempts, tracheal stenosis or upper airway mass, history of angioedema or anaphylaxis, cardiogenic pulmonary edema, ARDS.
  • Treatment: 40 mg IV Solumedrol, inhaled racemic epinephrine and reassess in 60 minutes. If still present or patient has respiratory distress, consider re-intubation.
• Post-extubation respiratory failure: hypoxic or hypercapnic -highest risk within 24 hours post-extubation.
  • Risk factors: ARDS, PNA, Volume Overload, Sepsis.
  • Consider blood gas 20-30 minutes post-extubation. Unless select high risk population discussed above, rescue BiPAP not shown to prevent re-intubation. If showing signs of respiratory distress, consider re-intubation.