II. Preparation: Cuff
- Use cuffed ET Tube for all children over 3 kg and adults
- Low pressure, high volume cuff
- Audible air leak on ventilation pressure >20-30cm H20
- Previously recommended to use uncuffed ET Tube for children under age 8 years
- Normal narrowing at cricoid is "natural cuff"
- Cuffed tubes are now routinely used for all ages (aspiration prevention) except for weight <3 kg
- Monitor cuff pressure to prevent necrosis at the cricoid ring
- To accomodate cuff size, drop uncuffed tube size estimate by 0.5 mm
III. Preparation: Stylet
- Recommended for use on all ET Tubes (even pediatric)
- Make certain the stylet does not protrude past the tube end
- Lubricate stylet for easy removal (especially with hyperangulated devices such as Glidescope)
- Stylet (and ET) should be "straight to cuff" in Direct Laryngoscopy (Levitan technique)
- Stylet is straight until the cuff, and then has hockey stick shaped 30 degree angulation at the tube end
- Avoid classic arcuate curvature, which reduces maneuverability of the distal ET Tube tip
- Stylet (and ET) should approximate the Laryngoscope Blade shape of hyperangulated devices (e.g. Glidescope)
- Glidescope uses specifically designed stylets for their devices
- 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
- Internal Diameter (ID)
- Newborns
- Newborn <28 weeks (<1000 g): 2.5 mm
- Newborn 28-34 weeks (1000-2000 grams): 3.0 mm
- Newborn 34-38 weeks (2000-3000 grams): 3.5 mm
- Newborn >38 weeks (>3000 grams): 3.5 to 4.0 mm
- Infant under 6 months: 3.5 - 4.0 mm
- Infant under 1 year: 4.0 - 4.5 mm
- Child under 2 years: 4.5 - 5.0 mm
- Child over 2 years
- Uncuffed Tube = (Age in years)/4 + 4mm
- Cuffed Tube = (Age in years)/4 + 3.5mm
- Cuffed tube sizes should be dropped by 0.5 mm
- Adult Female: 7.0 - 8.0 mm
- Adult Male: 8.0 - 8.5 mm
- Alternative Method: Length based (Broselow Tape)
- Newborns
- Outside Diameter
- Estimated by size of child's little (pinky) finger
- Distance or Depth of Insertion (from distal tube tip to lip)
- Marking at bottom of ET Tube should be at cord level
- Estimate: Multiply ET Internal Diameter by 3 centimeters
- Newborns ('Tip to Lip' distance = 6 + Weight in Kg)
- Prepare by cutting ET Tube to 13 to 15 cm
- Weight 1 kg: Insert 7 cm depth
- Weight 2 kg: Insert 8 cm depth
- Weight 3 kg: Insert 9 cm depth
- Weight 4 kg: Insert 10 cm depth
- Infant under 6 months: 10 cm
- Infant under 1 year: 11 cm
- Child under 2 years: 12 cm
- Child over 2 years: (Age in years)/2 + 12 cm
- Adult: 20-22 cm
- Suction catheter to fit within ET Tube
- ET Tube 2.5 mm: Use 5 or 6 French Catheter
- ET Tube 3.0 mm: Use 6 or 8 French Catheter
- ET Tube 3.5 mm: Use 8 French Catheter
- ET Tube 4.0 mm: Use 8 or 10 French Catheter
V. Preparation: Estimating other tube sizes based on ET Tube size
- Mnemonic: 1 to 2, 2 to 4
- ETT x 1 =
- Uncuffed: (Age/4) + 4 mm
- Accurate for age over 2 years (see above)
- Uncuffed Endotracheal Tube size estimate (subtract 0.5 mm for a cuffed tube size)
- Cuffed: (Age/4) + 3 mm
- Uncuffed: (Age/4) + 4 mm
- ETT x 2 = Nasogastric Tube, Orogastric Tube or Foley Catheter tube size
- ETT x 3 = Endotracheal Tube depth of insertion
- ETT x 4 = Chest Tube size (maximum)
VI. Preparation: Adjuncts
- Endotracheal Tubes with sub-glottic suction ports (subglottic secretion drainage or SSD)
- Reduces Ventilator-Associated Pneumonia (VAP) by as much as 75%
- Mucous plugging of suction ports is common
- Clear plugs with sterile water or air bolus
- Manufacturers recommended suction settings
- Continuous low pressure suction (<20 mmHg) or
- Intermittent suction for 10-15 sec (at 100-150 mmHg)
- But significantly increases Endotracheal Tube outer diameter (OD) for a given internal diameter (ID)
- ET with a 7.5 mm ID tube has a 10.2 mm OD, but is 11.2 mm OD with suction port
- 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
- Levitan (2013) Practical Airway Management Course, Baltimore