Endotracheal Intubation

Aka: Endotracheal Intubation, Laryngoscopy, Direct Laryngoscopy, Video Laryngoscopy, Post-intubation Management, Post-Intubation Cardiac Arrest, BURP Maneuver, LEMON Mnemonic

advertisement

II. Indications

  1. See Advanced Airway

III. Precautions

  1. See Rapid Sequence Intubation regarding peri-intubation precautions (e.g. Hypotension)
  2. Intubation attempts should not last >30 seconds
    1. Limit intubation attempt to 20 seconds in newborns
    2. Apneic Oxygenation may allow longer safe intubation times
  3. Optimize first attempt at intubation
    1. Encourage strategies that increase likelihood of first intubation attempt success (e.g. Video Laryngoscopy, bougie)
    2. First pass attempt has the lowest complication rate and marked complication rate after 2 intubation attempts
    3. Mort (2004) Anesth Analg 99(2): 607-13 [PubMed]
  4. Preoxygenate with 100% Oxygen
    1. See Endotracheal Intubation Preoxygenation
    2. Infants and children desaturate very quickly
      1. Intubation attempts should be brief and stopped as Oxygen Saturation drops below 90%
      2. Stop and re-oxygenate prior to another attempt
  5. Consider using an Oral Airway in infants and young children
    1. Infants have a large Tongue for their small Mandible
    2. Oral Airway may help keep the Tongue out of the way for the intubation
  6. Critical to avoid Vomiting during intubation
    1. Aspiration during intubation can be lethal
    2. Ensure adequate induction and paralytic dosing
      1. Rocuronium offers longer paralysis duration and may be considered in difficult airway
    3. Wait at least 60 seconds following paralytic to minimize Vomiting risk
    4. Decompress Bowel Obstruction or significantly distended Abdomen prior to intubation
      1. Consider Nasogastric Tube prior to intubation
    5. Elevate head of bed
    6. Avoid aggressive bag-valve-mask technique prior to intubation (prevent Stomach insufflation)
    7. Exercise extreme caution with awake techniques (careful to avoid gag stimulation)
      1. Consider pretreatment with Antiemetic
    8. Two forms of suction on and immediately available
      1. Open suction tubing
      2. Yanker suction (or better suction tip such as “S3,” “Big Stick,” and “Big Yank”)
        1. https://www.annemergmed.com/article/S0196-0644(16)30793-4/fulltext
  7. Anticipate difficult Direct Laryngoscopy (Mnemonic: LEMON)
    1. Look externally (gestalt)
      1. Long or short Mandible
      2. High arched Palate
      3. Short neck
      4. Facial Trauma
    2. Evaluate the 3-3-2 rule
      1. Significantly more or less than these values suggests more difficult airway management
      2. Measure each of 3 parameters using patient's own finger breadths
        1. Three fingers of mouth opening
        2. Three fingers between mentum and hyoid
          1. Length >5 cm (adults) is most predictive single factor for first pass success
        3. Two fingers between hyoid and Thyroid cartilage
      3. Images
        1. entAirwayLemon332.jpg
    3. Mallampati Score
      1. Class 3 to 4 suggests higher risk
      2. Class 4 is associated with a 10% failed first pass rate
      3. Images
        1. entMallampatiAll.jpg
    4. Obstruction ("hot potato voice", inability to swallow secretions, Stridor)
      1. Severe Angioedema
      2. Supraglottic swelling
      3. Smoke Inhalation
    5. Neck mobility reduced (e.g. Cervical Spine Immobilization, Rheumatoid Arthritis)
      1. Less of an impact if a hyperangulated blade (e.g. Glidescope) is used

IV. Protocol: Preparation

  1. See Endotracheal Intubation Preparation
    1. Includes SOAP-ME Mnemonic
  2. See Endotracheal Tube (includes Endotracheal Tube Stylet)
    1. Size and length selection of Endotracheal Tubes
    2. Lubricate stylet for easy removal (especially with hyperangulated devices such as Glidescope)
  3. See Extraglottic Device
    1. Includes Laryngeal Mask Airway or LMA
    2. Consider as emergency device in case of Endotracheal Intubation failure
  4. See Endotracheal Intubation Preoxygenation
    1. Includes Apneic Oxygenation
    2. Significantly extends duration of safe apnea during intubation
  5. See Direct Laryngoscope
    1. Includes sizes of Miller Blade and Macintosh Blade
  6. See Video Laryngoscope
    1. Includes Video Laryngoscopy devices such as Glidescope, C-MAC, MacGrath

V. Protocol: Positioning

  1. Optimal head and neck position
    1. Ear to sternal notch positioning (Levitan)
      1. Functional Residual Capacity (FRC) is decreased 20% in supine position (as compared with head forward position)
      2. Head should be forward with ear and Sternum should be at the same horizontal level
      3. Mandible should also be forward to maximize Thyroid to mental distance (and maximize mouth opening)
      4. Approximates the tripod position of a child in respiratory distress (head forward and jaw forward)
    2. Head on pillow(s) flexes the neck forward on the chest and head extended at the neck (Walls)
      1. Same position as ear to sternal notch position described above
    3. Sniffing position
      1. Sniffing position is with the head/neck extended and the face parallel with the ceiling
      2. Sniffing position is similar to Ear to sternal notch positioning and the Head on pillow position
      3. Sniffing position is preferred over ramp position, for its better first-pass success, glottic view and less Hypoxia
        1. Semler (2017) Chest +PMID:28487139 [PubMed]
  2. Children
    1. Simple maneuvers (e.g. Jaw Thrust) are most effective in children
    2. Keep head position in midline to prevent soft tissue from obscuring view when head turned to side
    3. Children age > 2 years (Without C-Spine Injury)
      1. Head extension with pillow under occiput
      2. Chin lifted into sniffing position
    4. Infants age < 2 years
      1. Large occiput naturally extends the large head
      2. Chin lifted to sniffing position
      3. Infants may need a small towel roll under the Shoulders to align the head
  3. Trauma
    1. See Emergency Airway Management
    2. In-line stabilization technique
      1. Assistant holds head down on bed, with little fingers applied to each ear to prevent side to side motion
      2. Remove Cervical Collar completely for intubation
      3. Load Elastic Bougie in side of mouth
      4. Orman and Weingart in Majoewsky (2013) EM:Rap 13(4):
    3. Precautions
      1. In-line stabilization may be ineffective and potentially harmful
        1. Manoach (2007) 50(3): 236-45 PMID:17337093 [PubMed]
        2. Santoni (2009) Anesthesiology 110(1): 24-31 [PubMed]
        3. Turner (2009) J Trauma 67(1): 61-6 [PubMed]
      2. In-line stabilization significantly prolongs intubation time and decreases first-pass success
        1. Thiboutot (2009) Can J Anaesth 56(6): 412-8 PMID: 19396507 [PubMed]
  4. Adjuncts
    1. See below for techniques to best visualize the cords
    2. Blood, vomitus or secretions in airway
      1. See above regarding 2 suctions available, elevated head of bed and aspiration avoidance
      2. Consider Nasogastric Tube placement prior to intubation
      3. Be ready with double set-up for failed airway (e.g. Cricothyrotomy with neck marked)
      4. Consider using suction tip to lead in front of the Laryngoscope (SALAD technique)
        1. Examiner holds Laryngoscope in left hand and suction in right
        2. Suction can also be used to retract the right side of the mouth to improve visibility
        3. May push suction catheter to the left side and leave in place while passing bougie
          1. Held together with Laryngoscope in left hand
        4. If catheter tip large enough, may pass suction tip through cords and bougie through catheter
          1. Bougie will fit through a large bore suction catheter tip (but not a yanker)
      5. Consider intubation of the Esophagus and inflating the balloon
        1. Push esophageal ET Tube to the left side (out of the way, but blocking GI secretions)
        2. Then intubate the trachea
      6. References
        1. Strayer in Herbert (2018) EM:Rap 18(11):1-3
    3. Avoid Cricoid pressure (Sellick Maneuver)
      1. No longer recommended in 2013
        1. Worsens airway visualization
          1. Oh (2013) Ann Emerg Med 61(4): 407-13 [PubMed]
        2. Does not prevent aspiration
          1. Fenton (2009) Int J Obstet Anesth 18(2): 106-10 [PubMed]
      2. May facilitate glottis viewing if performed correctly (but typically worsens visualization in practical use)
      3. Optional in 2010 ACC Guidelines
        1. Does not prevent aspiration
        2. May impede intubation if performed incorrectly

VI. Technique

  1. See Rapid Sequence Intubation
  2. Head and Neck Position are described above
  3. Hand Position: Infant (reverse for left hand dominant)
    1. Left Thumb and Index finger hold Laryngoscope
    2. Left middle and ring finger hold chin
    3. Left pinky finger pushes down on Larynx
    4. Right hand inserts ET Tube
  4. Adjuncts: Elastic Bougie
    1. Consider holding Elastic Bougie, placed by right molars while positioning Laryngoscope
    2. Allows for quick placement of Elastic Bougie in difficult airways without losing sight of the cords
    3. Not helpful in young children due to an incomplete calcification of tracheal rings
    4. Reference
      1. http://emcrit.org/wee/bougie-prepass-and-criccon/
  5. Endotracheal Tube insertion
    1. Approach: Levitan technique for Direct Laryngoscopy (two landmark)
      1. Start with "epiglottoscopy"
        1. Insert Laryngoscope in midline with finger hold at the blade-Laryngoscope junction
        2. Advance until epiglottis is visualized
        3. Tongue can be swept at this point
      2. Visualize arytenoid cartilages (corneiform tubercle, corniculate tubercle) at posterior end of aryepiglottic folds
        1. Cartilages attach to the vocal ligaments (Vocal Cords) and articulate in and out to open and close the glottis
        2. Cartilages form a distinct, easily recognizable boundary between Larynx (anterior) and Esophagus (posterior)
        3. Distinct cartilage appearance alone is an adequate landmark
          1. Even without direct visualization of the Vocal Cords (upside-down V)
        4. Visualize the Endotracheal Tube passing anterior to the arytenoid cartilages
          1. Nearly ensures entry through the Larynx and trachea
      3. References
        1. Levitan (2013) Practical Emergency Airway Management Course
    2. Insert Laryngoscope
      1. Direct Laryngoscopy
        1. Levitan recommends inserting in Laryngoscope in midline to visualize epiglottis
          1. Then sweep the Tongue to side
        2. Standard technique recommends inserting Laryngoscope into right mouth (at the Tonsillar Pillars)
          1. Then sweep Tongue to midline
      2. Glidescope (Video Laryngoscopy)
        1. Insert Glidescope in midline and without Tongue sweep
        2. Do not insert glidescope too far
          1. Excessive depth is a very common reason for an inability to pass the ET Tube
          2. Indications to withdraw Laryngoscope a few centimeters
            1. ET Tube passage is difficult (also confirm use of hyperangulated stylet)
            2. Cords are seen at close range
    3. Extend blade over base of Tongue
      1. Insertion location depends on blade type
        1. Curved blade (Macintosh Blade): Tip into vallecula
        2. Straight Blade (Miller Blade): Tip over the epiglottis
        3. Caveat: Curved blades may be used as straight blades (over the epiglottis) and vice versa
      2. Avoid entering Esophagus first
        1. Risk of Laryngeal Trauma
        2. Visualize the epiglottis first and then advance
      3. Pointers in young children (typically straight blade)
        1. Insert the blade midline (does not require sweeping Tongue except possibly in syndromic children)
        2. Avoid inserting the Laryngoscope Blade too far and then pulling back
          1. Landmarks are difficult to interpret (esopagus may appear similar to trachea in children)
        3. Insert the blade only to the Tongue base and then lift at a 45 degree angle
        4. May insert the blade slightly further (millimeter) if the epiglottis still in way
    4. Exert traction upward along axis of handle (after epiglottis visualized)
      1. Straightens the airway for a direct line of intubation
      2. Do not use teeth or gums as a fulcrum
        1. Results in significant oral/Dental Trauma
      3. Exception: Glidescope intubation requires no upward traction
        1. However airway is not straightened, so must use the glidescope stylet with the deep hockey-stick distal bend
        2. Due to unstraightened airway with glidescope, unbent ET Tube will be difficult to target the trachea
    5. Employ techniques to best visualize the cords
      1. Avoid cricoid pressure (see above)
      2. Bimanual Intubation Technique (Levitan)
        1. While left hand holds Laryngoscope, right hand manipulates Thyroid catilage (as in BURP technique)
        2. Intubating clinician initially manipulates the Thyroid cartilage (instead of assistant)
        3. Once positioned, assistant may be used to hold position while intubator passes ET Tube
      3. BURP Alternative in children
        1. Intubator places their hand over an assistants hand which is in turn held over the anterior neck
        2. Intubator moves the assistants hand (especially backwards) to align airway
        3. When cords are well visualized, assistant holds position and inubator removes their hand
        4. Especially useful in in young children who typically have an anterior positioned Larynx
      4. BURP Maneuver
        1. Assistant moves Thyroid cartilage backward, upward and rightward
        2. Less effective in young children
        3. Bimanual technique is preferred (see above)
    6. Tube insertion
      1. Slow down the Endotracheal Tube insertion (avoid ramming the tube into the airway)
      2. Avoid obstructing view on tube insertion
        1. Endotracheal Tube shape in Direct Laryngoscopy should be straight-to-cuff
          1. ET Tube is straight until distal end near cuff, where the stylet is bent 30 degrees up
          2. When inserted, the tube is hidden below the horizon until rises at level of Larynx
      3. Other strategies to avoid obstructing view
        1. Insert ET Tube from the right corner of mouth
      4. Hyperangulated devices (e.g. Glidescope)
        1. See Endotracheal Tube Stylet
        2. Once tube passes through cords, it will catch on anterior tracheal rings due to hyperangulation
        3. Stylet must be at least partially withdrawn or tube rotated 90 degrees right (clockwise) to further insert ET
        4. Hold ET Tube tightly as stylet is pulled out following tube placement
          1. Stylet may be wedged in tube and can result in dislodging the tube
          2. Stylet should be pulled out by withdrawing toward the patient's feet (instead of straight up)
    7. Position ET Tube
      1. Black marker on ET Tube at level of cords
      2. Cuffs should be placed just below cords
      3. See Endotracheal Tube for insertion depths for children
      4. Typically 23 cm for men, 21 cm for women

VII. Evaluation: Initial Assessment of Tube Position

  1. Confirming tracheal placement is among the most critically important steps in Endotracheal Intubation
    1. When in doubt, pull the tube
  2. Positive Pressure Ventilations to assess tube position
    1. Avoid over-ventilating (too fast or with too much volume)
      1. Hold the bag-valve-mask under-handed like a football hold
      2. Squeeze with only one hand
      3. Deliver initials breaths at one breath every 6 seconds in adults
    2. Observe for symmetric, bilateral chest rise (at a level just below the clavicles)
    3. Auscultate for equal breath sounds
      1. Chest auscultation at mid-axillary line (least likely to hear transmitted sounds from epigastrium)
    4. Assess resistance to manual bag mask ventilation
      1. Bag compression with properly placed ET Tube should be easy with little resistance
        1. However, resistance will be increased in poor Lung Compliance and Obstructive Lung Disease (e.g. Asthma)
      2. After inflating the lungs, air should return rapidly to refill the bag
      3. Contrast with esophageal intubation associated with resistance to bagging, and poor bag reinflation
  3. Other examination findings of proper ET Tube placement
    1. Document absent breath sounds over Stomach
    2. Vapor condenses on inside of tube with exhalation
  4. End-tidal carbon dioxide (End-Tidal CO2 Detector, required by new guidelines 2010)
    1. May be low if Cardiac Output low (esp. infants)
    2. Loss of EtCO2 wave form may be loss of pulse (instead of esophageal intubation)
      1. Check a pulse first, prior to removing an Endotracheal Tube
    3. Colorimetric EtCO2 may also be used
      1. Observe color changes (e.g. purple to yellow) after first 5-6 breaths
      2. Device is purple at CO2 <4 mmHg, partially yellow at CO2 4 to 14 mmHg, and fully yellow at CO2 >14 mmHg
      3. False Positives have occurred (esp. from gastric insufflation before ET Tube placement)
      4. False Negatives may occur in Cardiac Arrest and post-ROSC when circulation is too poor to return CO2 to alveoli
  5. Confirmation with Ultrasound
    1. Ultrasound can be used to distinguish endotracheal from esophageal intubation
    2. Place the high frequency probe in Transverse Lie over the anterior midline neck
      1. Slide the Ultrasound down toward the sternoclavicular notch
    3. Ultrasound can confirm Endotracheal Tube above carina
      1. May be performed by a second operator while the other is intubating
      2. Only one air filled lumen should be present with Endotracheal Tube placement (Esophagus collapsed)
        1. Two air filled lumens suggests esophageal intubation
      3. Fill ET Tube balloon with saline and can see the top of balloon at sternal notch
      4. https://vimeo.com/155465873

VIII. Protocol: Post-intubation Management

  1. Secure ET Tube
    1. Confirm tube position again by auscultation
    2. Note the distance marker at lips in chart
    3. Commercial tube holder highly recommended
      1. If holder is not available, tape ET Tube in place and fix to cheek with benzoin
  2. Orogastric Tube or Nasogastric Tube (if no Basilar Skull Fracture risks)
    1. Helps prevent aspiration
    2. Decompresses Stomach air (gastric insufflation air instilled with Bag Valve Mask)
    3. Reduces Stomach volume which can interfere with ability to ventilate (especially in children)
  3. Chest XRay
    1. Confirm tube position depth
    2. Endotracheal Tube should be ~2 cm above the carina and below the level of the clavicles
  4. Manage Low Blood Pressure (post-intubation Hypotension)
    1. See Push Dose Pressor
    2. IV Fluid bolus
  5. Post-Intubation Sedation and Analgesia
    1. See Post-Intubation Sedation and Analgesia
    2. Adequate sedation is critical to start early (esp. for paralysis with Rocuronium)
  6. Post-Intubation mechanical Ventilator settings
    1. See Mechanical Ventilator
    2. See Ventilator Troubleshooting
  7. Raise head of bed
    1. Head of bed to 30 degrees (up to 45 degrees)
    2. Reduces aspiration risk and improves ventilation
    3. Decreases Intracranial Pressure in Closed Head Injury
      1. Avoid raising head of bed >45 degrees (risk of decreased Cerebral Perfusion Pressure)
  8. Consider bite block
    1. Protects the Endotracheal Tube from teeth
    2. Allow for easier orotracheal suctioning
  9. Consider soft wrist restraints
    1. Prevents self-Extubation should patient become agitated
  10. Critical Care
    1. See Critical Care
    2. See Post-Cardiac Arrest Care

IX. Management: Hypoxemia - Trouble-Shooting Inadequate Ventilation or Oxygenation

  1. See Ventilator Troubleshooting
  2. See Mechanical Ventilation
  3. DOPE Mnemonic
    1. Dislodged tube
    2. Obstructed tube
    3. Pneumothorax
    4. Equipment failure
  4. Detailed approach
    1. Confirm tube positioned correctly as above
    2. Is ET Tube too small, cuff under-inflated?
    3. Is the pop-off valve on Resuscitation bag depressed?
      1. Higher ventilation pressures are needed with Near-drowning, Pulmonary Edema, and Asthma
    4. Is the Bag-Valve Device Leaking?
      1. Compress the bag against an Occluded ET connection (air will be expelled from any leaks)
    5. Is the operator providing adequate tidal breaths?
    6. Is there a Pneumothorax present?
  5. Special Circumstances
    1. Negative Pressure Pulmonary Edema
      1. May result from laryngospasm during Endotracheal Intubation or with patient over-breathing Ventilator
    2. Freezing outdoor Temperatures (e.g. wilderness rescue)
      1. Endotracheal Tubes may become obstructed from frozen airway secretions
      2. Shake the tube and suction the material frequently in outdoor cold conditions

X. Management: Post-Intubation Hypotension

  1. Prevention based on Hypotension Risk Factors
    1. Pre-Intubation Hypotension, hemodynamic compromise
      1. Maximize intravascular Resuscitation prior to Endotracheal Intubation if possible
      2. Optimize with Intravenous Fluids and early Vasopressors prior to Endotracheal Intubation
    2. Shock Index (heartRate/systolicBP) > 0.8
      1. Deceptively compensated, normal pre-intubation systolic Blood Pressure
      2. As with pre-intubation Hypotension, optimize with Intravenous Fluids and early Vasopressors
  2. Pre and Post-Intubation Blood Pressure stabilization
    1. Intravenous Fluid bolus
    2. Push Dose Pressures (e.g. push dose Epinephrine)
  3. Evaluate for Endotracheal Intubation Related Causes of Hypotension
    1. Decreased sympathetic tone (RSI related Anesthetic, esp. Propofol)
    2. Impaired gas exchange (e.g. esophageal intubation, right mainstem intubation, Pneumothorax)
      1. Reevaluate tube placement
      2. Airway Suctioning
      3. Obtain Chest XRay
    3. Decreased venous return and Cardiac Output (Positive Pressure Ventilation with increased intrathoracic pressure)
      1. Higher risk in volume depleted patients
    4. Obstructive Lung Disease with air trapping and Breath Stacking (large Tidal Volumes, inadequate expiratory time)
      1. Disconnect the Ventilator to allow exhalation, then manual slow Bag Valve Mask
      2. Adjust Ventilator settings (decrease Respiratory Rate, permissive hypercapnia, faster inspiratory phase)
    5. Comorbid conditions
      1. Cardiogenic Shock
      2. Right ventricular dysfunction

XI. Management: Post-Intubation Cardiac Arrest

  1. Cardiac Arrest occurs in 2-4% of intubated patients
    1. Occurs twice as often in emergent intubation (in contrast to planned intubation)
    2. Rhythm is typically Bradycardia or Pulseless Electrical Activity
  2. Risk Factors
    1. Advanced age (older patients)
    2. High Body Mass Index
    3. Multiple intubation attempts with prolonged apnea
      1. Endotracheal Intubation Preoxygenation
    4. Hypotension
    5. Hypoxia
    6. Severe Metabolic Acidosis
  3. Reversible Cardiac Arrest Causes
    1. See Reversible Causes of Cardiopulmonary Arrest (5H5T)
    2. Evaluate with Bedside Ultrasound (e.g. Pericardial Tamponade, Tension Pneumothorax)
    3. Peri-Intubation Hypotension (Hypovolemia)
      1. See Management of Post-Intubation Hypotension above
      2. Correct with fluid bolus and Vasopressors (e.g. Epinephrine)
    4. Tension Pneumothorax
      1. Empirically place bilateral Chest Tubes
    5. Pericardial Tamponade
      1. Intubation decreases intrathoracic pressure and Preload
    6. Esophageal Intubation
      1. Immediately after ET placement, confirm tube position with Capnography, auscultation
      2. Use Laryngoscope to recheck ET position and if unclear position, consider Extubation
    7. Severe Metabolic Acidosis
      1. Match ventilator Respiratory Rate prior to pre-intubation Respiratory Rate
        1. Low Respiratory Rates will worsen Metabolic Acidosis (e.g. Salicylate Poisoning, DKA)
      2. Minimize apnea during intubation
        1. Optimize chance of first pass success at Endotracheal Intubation
      3. Sodium Bicarbonate is UNLIKELY to have significant benefit (beyond toxicology use)
        1. Sodium Bicarbonate relies on Ventilatory effort for expelling CO2
        2. Sodium Bicarbonate is unlikely to offer benefit over the matched Ventilatory rate

XII. Resources

  1. Airway Cam (Levitan)
    1. http://www.airwaycam.com/
  2. Airway World (Walls, requires free registration to view videos)
    1. https://amec.6connex.com/portal/airwayworld/login
  3. Glidescope Intubation technique
    1. http://www.youtube.com/watch?v=mX0zZz6XABA
  4. Glidescope with 6 intubations
    1. http://www.youtube.com/watch?v=P3QQsNCwXKk
  5. Elastic Bougie Intubation
    1. http://www.youtube.com/watch?v=_QLabcsncwc
  6. Laryngeal Mask Airway (LMA) Insertion
    1. http://www.youtube.com/watch?v=96e46PyARaU
  7. CombiTube Insertion
    1. http://www.youtube.com/watch?v=c0FgnV71YIY

XIII. References

  1. Copeland and Mehta (2024) Crit Dec Emerg Med 33(9): 27-35
  2. Dettmer (2021) Crit Dec Emerg Med 35(7): 3-7
  3. Gausche-Hill and Claudius in Majoewsky (2012) EM-RAP 12(12): 6-7
  4. Levitan (2013) Practical Airway Management Course, Baltimore
  5. Majoewsky (2012) EM: RAP-C3 2(5): 3-4
  6. Roginski, Hogan and Buscher (2020) Crit Dec Emerg Med 34(6): 17-27
  7. Walls (2012) Emergency Airway Management, 3rd Ed, Lippincott, Philadelphia, p. 63-80

Images: Related links to external sites (from Bing)

These images are a random sampling from a Bing search on the term "Endotracheal Intubation." Click on the image (or right click) to open the source website in a new browser window. Search Bing for all related images

Related Studies

Related Topics in Procedure

advertisement