II. Preparation: Cuff

  1. Use cuffed ET Tube for all children over 3 kg and adults
    1. Low pressure, high volume cuff
    2. Audible air leak on ventilation pressure >20-30cm H20
  2. Previously recommended to use uncuffed ET Tube for children under age 8 years
    1. Normal narrowing at cricoid is "natural cuff"
    2. Cuffed tubes are now routinely used for all ages (aspiration prevention) except for weight <3 kg
      1. Monitor cuff pressure to prevent necrosis at the cricoid ring
      2. To accomodate cuff size, drop uncuffed tube size estimate by 0.5 mm

III. Preparation: Stylet

  1. Recommended for use on all ET Tubes (even pediatric)
  2. Make certain the stylet does not protrude past the tube end
  3. Lubricate stylet for easy removal (especially with hyperangulated devices such as Glidescope)
  4. Stylet (and ET) should be "straight to cuff" in Direct Laryngoscopy (Levitan technique)
    1. Stylet is straight until the cuff, and then has hockey stick shaped 30 degree angulation at the tube end
    2. Avoid classic arcuate curvature, which reduces maneuverability of the distal ET Tube tip
  5. Stylet (and ET) should approximate the Laryngoscope Blade shape of hyperangulated devices (e.g. Glidescope)
    1. Glidescope uses specifically designed stylets for their devices
    2. Without stylet hyperangulation, ET Tube can not maneuver the sharp angle at the base of the Tongue (in non-straightened airway)

IV. Preparation: Determining Sizes

  1. Internal Diameter (ID)
    1. Newborns
      1. Newborn <28 weeks (<1000 g): 2.5 mm
      2. Newborn 28-34 weeks (1000-2000 grams): 3.0 mm
      3. Newborn 34-38 weeks (2000-3000 grams): 3.5 mm
      4. Newborn >38 weeks (>3000 grams): 3.5 to 4.0 mm
    2. Infant under 6 months: 3.5 - 4.0 mm
    3. Infant under 1 year: 4.0 - 4.5 mm
    4. Child under 2 years: 4.5 - 5.0 mm
    5. Child over 2 years
      1. Uncuffed Tube = (Age in years)/4 + 4mm
      2. Cuffed Tube = (Age in years)/4 + 3.5mm
        1. Cuffed tube sizes should be dropped by 0.5 mm
    6. Adult Female: 7.0 - 8.0 mm
    7. Adult Male: 8.0 - 8.5 mm
    8. Alternative Method: Length based (Broselow Tape)
  2. Outside Diameter
    1. Estimated by size of child's little (pinky) finger
  3. Distance or Depth of Insertion (from distal tube tip to lip)
    1. Marking at bottom of ET Tube should be at cord level
    2. Estimate: Multiply ET Internal Diameter by 3 centimeters
    3. Newborns ('Tip to Lip' distance = 6 + Weight in Kg)
      1. Prepare by cutting ET Tube to 13 to 15 cm
      2. Weight 1 kg: Insert 7 cm depth
      3. Weight 2 kg: Insert 8 cm depth
      4. Weight 3 kg: Insert 9 cm depth
      5. Weight 4 kg: Insert 10 cm depth
    4. Infant under 6 months: 10 cm
    5. Infant under 1 year: 11 cm
    6. Child under 2 years: 12 cm
    7. Child over 2 years: (Age in years)/2 + 12 cm
    8. Adult: 20-22 cm
  4. Suction catheter to fit within ET Tube
    1. ET Tube 2.5 mm: Use 5 or 6 French Catheter
    2. ET Tube 3.0 mm: Use 6 or 8 French Catheter
    3. ET Tube 3.5 mm: Use 8 French Catheter
    4. ET Tube 4.0 mm: Use 8 or 10 French Catheter

V. Preparation: Estimating other tube sizes based on ET Tube size

  1. Mnemonic: 1 to 2, 2 to 4
  2. ETT x 1 =
    1. Uncuffed: (Age/4) + 4 mm
      1. Accurate for age over 2 years (see above)
      2. Uncuffed Endotracheal Tube size estimate (subtract 0.5 mm for a cuffed tube size)
    2. Cuffed: (Age/4) + 3 mm
  3. ETT x 2 = Nasogastric Tube, Orogastric Tube or Foley Catheter tube size
  4. ETT x 3 = Endotracheal Tube depth of insertion
  5. ETT x 4 = Chest Tube size (maximum)

VI. Preparation: Adjuncts

  1. Endotracheal Tubes with sub-glottic suction ports (subglottic secretion drainage or SSD)
    1. Reduces Ventilator-Associated Pneumonia (VAP) by as much as 75%
      1. Dezfulian (2005) Am J Med 118: 11–8 [PubMed]
    2. Mucous plugging of suction ports is common
      1. Clear plugs with sterile water or air bolus
      2. Manufacturers recommended suction settings
        1. Continuous low pressure suction (<20 mmHg) or
        2. Intermittent suction for 10-15 sec (at 100-150 mmHg)
    3. But significantly increases Endotracheal Tube outer diameter (OD) for a given internal diameter (ID)
      1. ET with a 7.5 mm ID tube has a 10.2 mm OD, but is 11.2 mm OD with suction port
      2. ET with a 8.0 mm ID tube has a 11.0 mm OD, but is 11.8 mm OD with suction port

VII. References

  1. Levitan (2013) Practical Airway Management Course, Baltimore

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