Airway Management Notes

Airway Management

Introduction

• The primary aspect of patient care is ensuring adequate breathing.
• Disruption of breathing compromises oxygen delivery to tissues and cells.
• Oxygen reaches tissues and cells through breathing and circulation.

Anatomy of the Respiratory System

• The respiratory system includes all structures that make up the airway and facilitate breathing (ventilation).
• The airway is divided into the upper and lower airways.

Anatomy of the Upper Airway

• Components:
  • Nose
  • Mouth
  • Oral cavity
  • Pharynx
  • Larynx
• Main function: Warm, filter, and humidify air.
• Pharynx:
  • Muscular tube from nose and mouth to esophagus and trachea.
  • Consists of the nasopharynx, oropharynx, and laryngopharynx.
• Nasopharynx:
  • Filters dust and small particles.
  • Warms and humidifies air.
• Oropharynx: Posterior portion of the oral cavity.
• Epiglottis: Superior to the larynx.
• Larynx:
  • Complex structure of cartilages.
  • Marks the end of the upper airway and the beginning of the lower airway.
  • Thyroid cartilage forms a “V” shape anteriorly.
  • Cricoid cartilage is the first ring of the trachea.
  • Glottis is the area between the vocal cords.

Anatomy of the Lower Airway

• Function: Deliver oxygen to the alveoli.
• Components:
  • Trachea
  • Bronchi
  • Lungs
• Trachea:
  • Conduit for air entry into the lungs.
  • Divides at the carina into two main stem bronchi (right and left).
  • Bronchi are supported by cartilage and distribute oxygen to the lungs.
  • Bronchioles are made of smooth muscle and connect to alveoli.
  • Oxygen is transported back to the heart and distributed to the body.
• Thoracic Cavity:
  • Contains the heart, great vessels (vena cava and aorta).
• Mediastinum:
  • Contains the heart, great vessels, esophagus, trachea, major bronchi, and nerves.

Physiology of Breathing

• Respiratory and cardiovascular systems work together.
  • Ensuring oxygen and nutrients are delivered and carbon dioxide and waste products are removed.

Ventilation

• Physical act of moving air into and out of the lungs.
• Inhalation:
  • Active, muscular part of breathing.
  • Diaphragm and intercostal muscles contract, creating negative pressure in the thorax.
  • Lungs require chest and supporting structures to expand.
  • Partial pressure: Amount of gas in air or fluid (blood).
  • Oxygen and carbon dioxide diffuse until partial pressures are equal.
  • Inspiration delivers oxygen to the alveoli.
  • Tidal volume and dead space are key concepts.
• Exhalation:
  • Passive process, not normally requiring muscular effort.
  • Diaphragm and intercostal muscles relax; smaller thorax compresses air out of the lungs.
• Regulation of ventilation:
  • Complex series of receptors and feedback loops.
  • Failure to meet oxygen needs leads to hypoxia.
  • Regulation is based on pH changes in blood and cerebrospinal fluid.
  • Hypoxic drive is typically seen in end-stage COPD patients.

Oxygenation

• The process of loading oxygen molecules onto hemoglobin in the bloodstream.
• Required for internal respiration.
• Does not guarantee internal respiration.
• Ventilation without oxygenation can occur if oxygen levels are depleted.

Respiration

• Actual exchange of oxygen and carbon dioxide in alveoli and body tissues.
• Cells extract energy from nutrients through metabolism.
• External respiration (pulmonary respiration):
  • Brings fresh air into the respiratory system.
  • Exchanges oxygen and carbon dioxide between alveoli and blood in pulmonary capillaries.
• Internal respiration: Exchange of oxygen and carbon dioxide between systemic circulatory system and cells.

Pathophysiology of Respiration

• Nervous system factors:
  • Chemoreceptors monitor oxygen, carbon dioxide, hydrogen ions, and pH of cerebrospinal fluid.
  • Provide feedback to respiratory centers.
• Ventilation/perfusion ratio and mismatch:
  • Air and blood flow must be directed to the same place at the same time.
  • Ventilation and perfusion must be matched.
  • Failure to match causes abnormalities in oxygen and carbon dioxide exchange.
  • Gas exchange does not take place, leading to lack of oxygen and recirculation of carbon dioxide in the bloodstream, causing severe hypoxemia.
• Factors affecting pulmonary ventilation:
  • Intrinsic factors: Infections, allergic reactions, unresponsiveness (tongue obstruction).
  • Extrinsic factors: Trauma.
• Factors affecting respiration:
  • External factors: Atmospheric pressure, partial pressure of oxygen.
  • Internal factors: Pneumonia, pulmonary edema, COPD/emphysema.
• Circulatory compromise:
  • Trauma emergencies can obstruct blood flow:
    • Simple or tension pneumothorax
    • Open pneumothorax
    • Hemothorax
    • Hemopneumothorax
  • Other causes: Blood loss, anemia, hypovolemic shock, vasodilatory shock.

Patient Assessment

• Aerosol-generating procedures (AGPs):
  • CPR
  • Nebulizer treatments
  • Endotracheal intubation
  • Continuous positive airway pressure
• Recognizing adequate breathing:
  • Between 12 and 20 breaths/min.
  • Regular pattern of inhalation and exhalation.
  • Bilateral clear and equal lung sounds.
  • Regular, equal chest rise and fall.
  • Adequate depth (tidal volume).
• Recognizing abnormal breathing:
  • Fewer than 12 breaths/min or more than 20 breaths/min.
  • Irregular rhythm.
  • Diminished, absent, or noisy breath sounds.
  • Reduced airflow at nose and mouth.
  • Unequal or inadequate chest expansion.
  • Increased effort of breathing.
  • Shallow depth.
  • Pale, cyanotic, cool, or moist skin.
  • Skin pulling in around ribs or above clavicles during inspiration.
• Agonal gasps: A patient may appear to be breathing after the heart has stopped.
• Cheyne-Stokes respirations: Irregular respirations followed by apnea, seen in stroke or head injury patients.
• Ataxic respirations: Irregular, unidentifiable pattern, may follow serious head injuries.
• Kussmaul respirations: Deep, rapid respirations, common in metabolic acidosis.
• Patients with inadequate breathing need immediate treatment.
• Level of consciousness and skin color are excellent indicators of respiration.
• Pulse oximetry is a routine vital sign for assessing oxygenation.

End-Tidal CO2

• Measurement of maximal CO2 at the end of an exhaled breath.
• Low CO2 level:
  • Hyperventilation
  • Decreased CO2 return to the lungs
  • Reduced CO2 production at the cellular level
• High CO2 level:
  • Ventilatory inadequacy
  • Apnea
• Normal range is 35–45 mm Hg.
• Measured using capnometry and capnography devices.

Opening the Airway

• Emergency care begins with ensuring an open airway.
• Rapidly assess if an unconscious patient has an open airway and is breathing adequately.
• Position the patient correctly in a supine position.
• Unconscious patients should be moved as a unit.
• The most common airway obstruction is the tongue.

Head Tilt-Chin Lift Maneuver

• Opens the airway in most patients without suspected trauma.
• Steps:
  • Position yourself beside the patient's head.
  • Place the heel of one hand on the forehead and apply firm backward pressure.
  • Place fingertips of the other hand under the lower jaw.
  • Lift the chin upward, lifting the entire lower jaw.

Jaw-Thrust Maneuver

• Used when cervical spine injury is suspected.
• Steps:
  • Kneel above the patient’s head.
  • Place fingers behind the angles of the lower jaw.
  • Move the jaw upward.
  • Use thumbs to help position the jaw.

Opening the Mouth

• Cross-finger technique:
  • Place tips of index finger and thumb on the patient’s teeth.
  • Push thumb on lower teeth and index finger on upper teeth.
  • The index finger and thumb cross over each other.

Suctioning

• Keeps the airway clear for proper ventilation.
• Essential equipment for resuscitation: portable, hand-operated, and fixed units.
• A portable or fixed unit should have:
  • Wide-bore, thick-walled, nonkinking tubing
  • Plastic, rigid pharyngeal suction tips
  • Nonrigid plastic catheters
  • A nonbreakable, disposable collection bottle
  • Water supply for rinsing tips

Techniques of Suctioning

• Inspect the equipment regularly.
• Check the unit for proper assembly of its parts.
• Test the suctioning unit to ensure vacuum pressure of more than 300 \, mmHg.
• Select and attach the appropriate suction catheter to the tubing.
• Never suction for more than 15 seconds at one time for adults, 10 seconds for children, and 5 seconds for infants to avoid hypoxia.
• If secretions or vomitus cannot be suctioned easily:
  • Remove the catheter.
  • Log roll the patient to the side.
  • Clear the mouth with a gloved finger.
• For frothy secretions:
  • Suction for 15 seconds (less in infants and children).
  • Ventilate for 2 minutes.
  • Continue alternating until clear.

Basic Airway Adjuncts

• Prevent obstruction by the tongue and allow passage of air and oxygen to the lungs.

Oropharyngeal Airways

• Keeps the tongue from blocking the upper airway and makes suctioning easier.
• Indications:
  • Unresponsive patients without a gag reflex
  • Apneic patients being ventilated with a bag-mask device
• Contraindications:
  • Conscious patients
  • Any patient with an intact gag reflex

Nasopharyngeal Airways

• Used in patients who are unresponsive or have an altered LOC, have an intact gag reflex and are unable to maintain their own airway.
• Indications:
  • Semi-conscious or unconscious patients with an intact gag reflex
  • Patients who will not tolerate an oropharyngeal airway
• Contraindications:
  • Severe head injury with blood in the nose
  • History of fractured nasal bone

Maintaining the Airway

• Use the recovery position to maintain a clear airway in an unconscious, uninjured patient who is breathing on their own.

Supplemental Oxygen

• Always give oxygen to hypoxic patients; some tissues and organs need a constant supply of oxygen.
• Never withhold oxygen from any patient who might benefit.

Supplemental Oxygen Equipment

• Oxygen cylinders contain compressed gas; liquid oxygen is becoming more common.
• Safety considerations:
  • Handle gas cylinders carefully.
  • Ensure the correct pressure regulator is firmly attached.
  • Secure cylinders when stored and during transport.

Pin-Indexing System

• Prevents mistakes like connecting an oxygen regulator to a carbon dioxide cylinder.
• Each cylinder of a specific gas type has a given pin pattern and number.

Pressure Regulators

• Reduce cylinder pressure to a therapeutic range of 40 to 70 psi.
• Final attachment for gas delivery is a quick-connect female fitting or flowmeter.

Flowmeters

• Usually permanently attached to pressure regulators.
• Types: Pressure-compensated flowmeter and Bourdon-gauge flowmeter.

Hazards of Supplemental Oxygen

• Combustion: Oxygen speeds up combustion, so keep fire sources away and ensure adequate ventilation.
• Oxygen toxicity: High concentrations can be detrimental to patients with certain illnesses (COPD); tailor oxygen therapy using pulse oximetry to maintain saturation at or above 94\%.

Oxygen-Delivery Equipment

• Nonrebreathing masks
• Bag-mask devices
• Nasal cannulas

Nonrebreathing Masks

• Preferred way to give oxygen in the prehospital setting for adequately breathing patients suspected of hypoxia.
• Combination mask and reservoir bag system.
• Ensure the reservoir bag is full before placing the mask.
• Adjust flow rate so the bag does not collapse when the patient inhales.
• Remove the mask when oxygen therapy is discontinued.

Nasal Cannulas

• Deliver oxygen through two small prongs in the nostrils.
• Provide 24\% to 44\% inspired oxygen when the flowmeter is set at 1–6 L/min.
• Used in patients with mild hypoxemia.
• Patients who breathe through the mouth or have a nasal obstruction will not benefit.
• Consider humidification for long transport times.

Partial Rebreathing Masks

• Similar to nonrebreathing masks, but without a one-way valve between the mask and the reservoir.
• Patients rebreathe a small amount of exhaled air.

Venturi Masks

• Settings can vary the percentage of oxygen while maintaining constant flow.
• Delivers 24\%–40\%.

Tracheostomy Masks

• For patients with tracheostomies who do not breathe through their mouth and nose.
• Cover the tracheostomy hole with a strap around the neck.
• If a tracheostomy mask is unavailable, use a face mask placed at the tracheostomy opening.

Assisted and Artificial Ventilation

• Basic techniques are highly effective.
• Follow standard precautions.

Signs and Symptoms of Inadequate Ventilation

• Altered mental status
• Inadequate minute volume
• Excessive accessory muscle use and fatigue

Assisting with a Bag-Mask Device

• Explain procedure.
• Place the mask over the nose and mouth.
• Squeeze the bag each time the patient breathes.
• Deliver appropriate tidal volume after the initial 5 to 10 breaths.
• Maintain an adequate minute volume.

Artificial Ventilation

• Begin immediately if a patient is not breathing via mouth-to-mask technique or bag-mask device.

Normal Ventilation vs. Positive Pressure Ventilation

• Normal breathing involves diaphragm contraction and negative pressure in the chest cavity.
• Positive pressure ventilation uses a device to force air into the chest cavity.

Effects of Positive Pressure Ventilation

• Increased intrathoracic pressure reduces blood pumped by the heart.
• More volume is required compared to normal breathing.
• Air is forced into the stomach, causing gastric distention.

Mouth-to-Mouth and Mouth-to-Mask Ventilation

• Barrier device is routinely used.
• A mask with an oxygen inlet provides oxygen during mouth-to-mask ventilation.

Bag-Mask Device

• Provides less tidal volume than mouth-to-mask ventilation.
• An experienced EMT can provide adequate tidal volume.

Gastric Distention

• Occurs when artificial ventilation fills the stomach with air.
• Likely to occur with forceful or rapid ventilation or airway obstruction.
• To prevent or alleviate distention:
  • Ensure the airway is appropriately positioned.
  • Ventilate at the appropriate rate and volume.
  • If the stomach appears distended, recheck and reposition the head and continue rescue breathing.

Passive Ventilation

• Expansion and contraction create a