Intubation and Extubation

Jacob Lee

Intubation

This section will discuss how an ideal intubation will work; intubations during codes are emergent scenarios where this process will differ.

Indications

  • Respiratory failure – hypoxic and/or hypercapnic; NOTE hypercapnia with a normal pH is not a reason to intubate, this is well compensated
  • Respiratory distress – angioedema or anaphylaxis with impending airway compromise, significantly increased work of breathing and pending ventilatory failure due to exhaustion
  • Airway protection – altered mental status without ability protect airway (prevent aspiration and clear secretions); GCS <8 -> intubate
    • Although recent study (NICO trial in JAMA) suggests that not intubating patients with acute overdose and GCS<8 is better (fewer complications, shorter ICU and hospital LOS) than intubation
  • Airway trauma – damage or penetrating injuries to larynx

Contraindications

  • Airway trauma/obstruction preventing safe placement of ETT; if definitive airway is needed in these cases, consider tracheostomy/cricothyrotomy
  • Not within goals of care. Confirm code status with patient, family, or surrogate

Considerations

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

**If overnight, Airway team must be called. See the following “Anesthesia Airway” section chapter**

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
    • Optimize medical status: Give appropriate resuscitation, temporize anemia (hgb >7) /electrolyte abnormalities (hyperkalemia)
  • 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. Push-dose pressors (Neostick’s=syringe of phenylephrine) also valuable 

*NOTE: we are currently doing a clinical trial on sedatives and paralytics to see if there is a superior regimen

  • Paralytic Agents:
    • Succinylcholine – depolarizing agent, faster onset (45-60 seconds), shorter duration (5-10 minutes) but should be avoided in hyperkalemia, burns, crush injuries, and neuromuscular disease (PD, MG, ALS)
    • Rocuronium – non-depolarizing agent, longer onset (45-90 seconds) longer duration (30-60 minutes) safer in CKD patients, as well as in NMD patients. Note, longer duration of action may outlast the duration of the induction sedative - risk for paralysis awareness
  • Induction sedatives:
    • Etomidate – hemodynamically stable to slight hypotension
    • Ketamine – hemodynamically stable, can be dually helpful for bronchospasm
    • Propofol – associated with hypotension
  • 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
  • Ventilate patients according to condition

Complications

  • Airway trauma (oropharyngeal, laryngeal/vocal cords)
  • Aspiration: Suction airway (ideally prior to initiation of PPV). Mixed data re whether cricoid pressure during intubation (i.e. Selleck maneuver) decreases risk of this.
  • 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

Anesthesia Airway

Editors: Mercede Erickson, MD, Camille Adajar, MD 

Faculty Editor: Brandon Pruett, MD

Call/text Airway

  • Phone: (615) 887-7369
  • Provides direct contact with the on-call resident/Airway Team (we 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 intubation sequence and intubation – other team members are not permitted to intubate under these circumstances per Anesthesiology Department protocol

Extubation

Assessing patients for extubation readiness

  • Patients should be assessed for extubation readiness on a daily basis 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. Precedex 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 (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 airway regimen
  • 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 to extubation. Will likely 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 (L) 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.
    • Note, rescue BiPAP to prevent re-intubation has not been shown to be beneficial and only found to delay reintubation. Exception: patient has known hypercapnea - then rescue BIPAP may actually rescue patients from re-intubation

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
    • 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.
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