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HLT-RESP80-05 · Lesson 6 · 47 clock hours · lab

Orotracheal Intubation Skills Lab

Objective. Students will perform orotracheal intubation on adult and pediatric manikins within the accepted time limit, confirming placement by waveform capnography, bilateral breath sounds, and absence of epigastric sounds.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed clinician in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it to make decisions about any patient or medication. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Orotracheal Intubation: Principles and Technique

Orotracheal intubation (OTI) is one of the most important skills a respiratory therapist performs. Placing an endotracheal tube (ET tube) through the mouth, past the vocal cords, and into the trachea provides a definitive, protected airway. A misplaced tube—especially one in the esophagus—can be rapidly fatal. Every step in this lab is built around preventing that outcome.

Equipment Selection

Laryngoscope blades come in two main types. The curved Macintosh blade tip sits in the vallecula (the space between the base of the tongue and the epiglottis); lifting indirectly elevates the epiglottis. The straight Miller blade tip passes under the epiglottis and lifts it directly. Adult intubations most commonly use a Mac 3 or Mac 4; pediatric intubations more often use a Miller blade because the infant/child epiglottis is relatively large and floppy. Blade size must match patient size—too small and you cannot see; too large and you can cause trauma.

ET tube sizing: For adults, a common starting point is 7.0–8.0 mm internal diameter (ID) for females and 7.5–8.5 mm ID for males, though you should always have one size smaller and one size larger available. For pediatric patients, a widely used formula for uncuffed tubes is: tube ID (mm) = (age in years ÷ 4) + 4. For cuffed pediatric tubes the formula adjusts slightly downward. Confirm the correct size with your program's reference card and instructor guidance.

Depth of insertion: A general adult estimate is approximately 21–23 cm at the teeth for females and 23–25 cm for males. A common pediatric estimate is: (age in years ÷ 2) + 12 cm at the lip. These are starting estimates—confirmation always supersedes the formula.

Stylet: Shape the ET tube into a gentle hockey-stick curve. The stylet tip must remain at least 1 cm proximal to the Murphy eye (tube tip) to prevent mucosal injury. Remove the stylet smoothly as soon as the tube passes the cords.

Performing Laryngoscopy

1. Pre-oxygenate the patient (or manikin) with 100% oxygen via BVM for at least 3 minutes (or 8 vital-capacity breaths) before the attempt.

2. Position: Place the patient in the sniffing position—neck slightly flexed on a small pillow, head extended at the atlanto-occipital joint—to align the oral, pharyngeal, and laryngeal axes.

3. Hold the laryngoscope in the left hand. Open the mouth with the right hand using a scissor maneuver.

4. Insert the blade along the right side of the mouth, sweeping the tongue to the left.

5. Advance the blade to the vallecula (Mac) or under the epiglottis (Miller), then lift along the handle axis—never lever back against the upper teeth. Levering is both a critical error and a source of dental trauma.

6. Visualize the glottis and vocal cords. Pass the ET tube from the right corner of the mouth, watching it pass through the cords under direct vision.

7. Advance until the cuff is 1–2 cm below the vocal cords, then inflate the cuff to the minimum pressure that seals the airway (typically 20–30 cmH₂O; always use a manometer in clinical practice).

8. Limit each laryngoscopy attempt to 30 seconds or less. If you have not achieved placement, withdraw, re-oxygenate, and retry.

Confirming Tube Placement: The Triple-Confirmation Method

No single method is infallible alone. Use all three:

1. Waveform capnography: A persistent, square-wave ETCO₂ tracing over multiple breaths is the gold-standard confirmation of tracheal placement. Colorimetric CO₂ detectors change color with CO₂ and serve as an alternative when waveform capnography is unavailable.

2. Bilateral breath sounds: Auscultate the lateral lung fields (avoid central auscultation, which can transmit esophageal sounds). Sounds should be equal bilaterally.

3. Absence of epigastric sounds: Listen over the epigastrium during the first ventilation. Gurgling here strongly suggests esophageal intubation—remove the tube immediately.

Also observe chest rise and check tube depth at the teeth. A chest X-ray confirms final depth in clinical settings.

Rapid Sequence Intubation (RSI) Awareness

In the RSI scenario, a provider administers a sedative/hypnotic followed by a neuromuscular blocking agent. Your role as the RT is to: confirm pre-oxygenation is complete, apply cricoid pressure if directed by the provider, perform laryngoscopy and intubation after the medications take effect, and confirm placement immediately. You do not select or administer RSI medications—that is outside the RT's scope in most states. However, you must recognize the medication sequence and understand that loss of muscle tone will follow.

Safety Points

Key terms10

Orotracheal intubationPlacement of an endotracheal tube through the mouth, past the vocal cords, and into the trachea to establish and protect a definitive airway.
Waveform capnographyContinuous real-time monitoring of exhaled carbon dioxide displayed as a waveform; the gold-standard method for confirming tracheal tube placement.
LaryngoscopyDirect visualization of the larynx using a laryngoscope handle and blade to guide endotracheal tube placement through the vocal cords.
ValleculaThe space between the base of the tongue and the epiglottis where the tip of a curved (Macintosh) blade is positioned during laryngoscopy.
Sniffing positionHead-positioning technique that aligns the oral, pharyngeal, and laryngeal axes to optimize visualization of the glottis during laryngoscopy.
Rapid sequence intubation (RSI)A technique in which a sedative/hypnotic and a neuromuscular blocking agent are given in rapid succession by a provider to facilitate intubation of a patient at risk for aspiration.
Cuff pressureThe pressure inside the ET tube cuff, typically maintained at 20–30 cmH₂O to create an effective tracheal seal while minimizing mucosal injury.
Triple-confirmation methodThe standard three-part verification of ET tube placement: waveform capnography (or colorimetric CO₂ detection), bilateral breath sounds, and absence of epigastric sounds.
Right mainstem intubationInadvertent advancement of the ET tube into the right main bronchus, resulting in ventilation of only the right lung; identified by absent or decreased breath sounds on the left.
StyletA malleable wire insert placed inside an ET tube to maintain a desired curve during intubation; must be withdrawn at least 1 cm from the tube tip to prevent airway trauma.

Worked examples4

1. Calculate the correct uncuffed ET tube internal diameter for a 4-year-old child.
  1. Use the formula: tube ID (mm) = (age in years ÷ 4) + 4
  2. Substitute the age: (4 ÷ 4) + 4
  3. Calculate: 1 + 4 = 5
Answer: A 5.0 mm ID uncuffed ET tube is the calculated starting size. Have 4.5 mm and 5.5 mm immediately available.
2. Estimate the correct depth of ET tube insertion at the lip for a 6-year-old child.
  1. Use the formula: depth (cm) = (age in years ÷ 2) + 12
  2. Substitute the age: (6 ÷ 2) + 12
  3. Calculate: 3 + 12 = 15
Answer: The estimated insertion depth is 15 cm at the lip. This is a starting estimate only; confirm placement with the triple-confirmation method and adjust as needed.
3. A child is 8 years old. What uncuffed ET tube size is appropriate, and what is the estimated insertion depth?
  1. Tube size formula: (age ÷ 4) + 4 = (8 ÷ 4) + 4 = 2 + 4 = 6.0 mm ID
  2. Depth formula: (age ÷ 2) + 12 = (8 ÷ 2) + 12 = 4 + 12 = 16 cm at the lip
  3. Have sizes 5.5 mm and 6.5 mm available as alternates
Answer: Use a 6.0 mm ID uncuffed ET tube inserted to approximately 16 cm at the lip. Confirm with waveform capnography, bilateral breath sounds, and absence of epigastric sounds.
4. During post-intubation assessment of an adult patient, breath sounds are heard clearly on the right but are absent on the left. The ETCO₂ waveform is present. What has likely occurred and what is the corrective action?
  1. Unilateral breath sounds (right only) with ETCO₂ present indicates the tube is likely in the right main bronchus rather than the mid-trachea—right mainstem intubation.
  2. Note the current tube depth at the teeth/lip.
  3. Deflate the cuff, withdraw the tube 1–2 cm, re-inflate the cuff to appropriate pressure.
  4. Re-auscultate bilaterally and recheck ETCO₂ waveform to confirm equal bilateral ventilation.
Answer: Right mainstem intubation is the likely cause. Withdraw the tube 1–2 cm, re-inflate the cuff, and reconfirm bilateral breath sounds plus continuous ETCO₂ waveform.

The math in this lesson1

Learners compute pediatric ET tube size and insertion depth from age-based formulas.
F-IF.2
In class: Each student performs a minimum of five adult intubations on the airway trainer under direct instructor observation, self-evaluating after each attempt using a video replay when available. · Perform at least two pediatric manikin intubations using correct blade selection, tube sizing, and depth of insertion calculation; confirm placement using the standard triple-confirmation method. · Participate in a simulated rapid sequence intubation (RSI) scenario in which the instructor calls out medication names and doses as given by a provider; student performs laryngoscopy and intubation after pre-oxygenation steps are verified.
Materials: Adult and pediatric intubation manikins/airway trainers, laryngoscope handles and blades, ET tubes (all sizes), waveform capnography simulator or actual colorimetric CO2 detector, stethoscope, BVM, tape, stylet, gloves, face shields, video laryngoscopy trainer if available
Check: Instructor skills checklist: student achieves confirmed tracheal placement (waveform capnography + bilateral breath sounds + no epigastric sounds) within the acceptable attempt time on three consecutive trials with zero critical errors; pass = zero critical errors on each of three consecutive attempts.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Patient Assessment and Airway Management
1. During a practice intubation, you achieve tube placement but hear gurgling over the epigastrium with the first ventilation. Waveform capnography shows a flat line. What is the most appropriate immediate action?
Patient Assessment and Airway Management
2. Which single method is considered the gold standard for confirming tracheal tube placement in patients who are not in cardiac arrest?
Equipment and Therapeutic Procedures
3. A student is preparing to intubate a 4-year-old child using an uncuffed ET tube. Using the standard pediatric formula, what tube internal diameter should be selected first?
Equipment and Therapeutic Procedures
4. When using a curved (Macintosh) laryngoscope blade, where should the blade tip be placed?
Patient Safety and Emergency Care
5. A respiratory therapy student is performing laryngoscopy and cannot visualize the cords after 35 seconds. What is the correct action?
Therapeutic Procedures and Scope of Practice
6. During a simulated RSI scenario, the instructor announces that the provider has administered a neuromuscular blocking agent. As the respiratory therapist, which of the following is your primary responsibility at this point?
Patient Assessment and Airway Management
7. After intubating an adult male patient, you note the tube is at 30 cm at the teeth. Breath sounds are absent on the left and present on the right. The most likely explanation is:
Equipment and Therapeutic Procedures
8. Which of the following represents a critical error that would result in automatic failure on the orotracheal intubation skills checklist?
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