Oxygen Delivery Devices & Ventilation

Providing supplemental oxygen and assisting ventilations are core EMT skills. Choosing the right device depends on the patient's condition and oxygen needs.

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Oxygen Delivery Devices

Nasal Cannula

• Delivers low-flow oxygen at 1-6 LPM.
• Each liter per minute increases FiO2 by approximately 4% above room air (21%).
• Comfortable for the patient and allows eating and speaking.
• Not appropriate for patients who are mouth-breathing exclusively.

Non-Rebreather Mask (NRB)

• The reservoir bag must be fully inflated before placing the mask on the patient.
• Run at 10-15 LPM to keep the reservoir bag inflated during inhalation.
• One-way valves on the mask prevent the patient from rebreathing exhaled CO2.
• Highest concentration of oxygen an EMT can deliver without assisting ventilations.

Bag-Valve Mask (BVM)

The BVM is the EMT's primary tool for assisting ventilations:

• Connected to supplemental O2 at 15 LPM, it delivers close to 100% oxygen.
• Without supplemental oxygen, it delivers approximately 21% (room air).

One-Rescuer BVM Technique:

1. Position yourself at the head of the patient.
2. Select the appropriate mask size.
3. Use the C-E clamp technique: form a "C" with thumb and index finger over the mask and an "E" with the remaining three fingers under the jaw.
4. Squeeze the bag to deliver approximately 500-600 mL per breath over 1 second.
5. Watch for visible chest rise — do NOT overventilate.

Two-Rescuer BVM Technique (preferred):

1. One rescuer holds the mask with both hands using bilateral C-E clamp technique for a better seal.
2. The second rescuer squeezes the bag.
3. This method provides a superior mask seal and more consistent ventilations.

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Airway Adjuncts

Oropharyngeal Airway (OPA)

• Purpose: Prevents the tongue from obstructing the airway in unconscious patients.
• Sizing: Measure from the corner of the mouth to the earlobe (or angle of the jaw).
• Insertion in adults: Insert with the tip pointing toward the roof of the mouth (upside down), then rotate 180 degrees as it passes over the tongue.
• Insertion in children: Insert with the tip pointed toward the tongue (right-side up) using a tongue depressor to hold the tongue down. Do NOT rotate — risk of trauma to the soft palate.
• Contraindication: Patients with a gag reflex. If the patient gags during insertion, remove it immediately.

Nasopharyngeal Airway (NPA)

• Purpose: Maintains airway patency; can be used in patients with or without a gag reflex.
• Sizing: Measure from the nostril to the earlobe (or tip of the nose to the earlobe).
• Insertion: Lubricate with a water-soluble lubricant, insert into the right nostril (or larger nostril) with the bevel toward the septum, and advance gently along the floor of the nasal cavity.
• Contraindication: Suspected basilar skull fracture (signs include raccoon eyes, Battle's sign, or cerebrospinal fluid leaking from nose/ears).

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Pulse Oximetry

Pulse oximetry (SpO2) measures the percentage of hemoglobin saturated with oxygen:

• Normal SpO2: 95-100%
• General target: Maintain SpO2 at 94% or above
• COPD patients: Target 88-92% — these patients may rely on a hypoxic drive for breathing, and excessive oxygen can suppress their respiratory drive
• Limitations: Pulse oximetry may be inaccurate in hypothermia, carbon monoxide poisoning, poor perfusion, nail polish, and anemia

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Suctioning

Suctioning removes blood, vomitus, secretions, and other fluids from the airway.

Key Suctioning Rules

• Maximum suction time: 15 seconds in adults, 10 seconds in children, 5 seconds in infants
• Suction on withdrawal only (not while inserting the catheter)
• Preoxygenate the patient before suctioning if possible
• Use a rigid (Yankauer) catheter for the oropharynx
• Use a flexible (French) catheter for the nasopharynx and through airway adjuncts
• If the patient has copious secretions requiring repeated suctioning, ventilate between each attempt