Airway Physiology

Structure and Function of the Airway

The airway is a critical anatomical system responsible for the passage of air into and out of the lungs. It is divided into upper and lower portions, each with distinct structures and functions.

• Upper Airway: Begins at the mouth and nose, includes the pharynx (nasopharynx, oropharynx, laryngopharynx), and ends at the larynx.

• Larynx: Serves as the boundary between the upper and lower airways.

• Lower Airway: Includes the trachea, mainstem bronchi, bronchioles, and alveoli. Gas exchange occurs at the alveolar-capillary interface.

Key Terms: Pharynx, Larynx, Trachea, Bronchi, Alveoli, Diaphragm

Pediatric Airway Physiology

Infants and children have unique airway characteristics that increase their risk of obstruction.

• Shorter, narrower, and less rigid airway structures

• Proportionately larger tongue

• Newborns and infants are nose breathers

• Softer, more flexible trachea

• Breathing is more dependent on the diaphragm

Airway Pathophysiology

Obstructions and Airway Compromise

Airway patency can be compromised by various obstructions and physiological changes.

• Obstructions: Foreign bodies (food, toys), liquids (blood, vomit), loss of muscle tone

• Acute vs. Chronic: Obstructions may develop suddenly or over time

• Swelling: Anaphylaxis, burns, trauma, and infections can cause rapid tissue swelling

• Smooth Muscle Constriction: Changes airway diameter and increases resistance

Sounds of a Partially Obstructed Airway:

• Stridor: High-pitched whistling, severe narrowing

• Hoarseness: Raspy voice, swelling near vocal cords

• Snoring: Diminished muscle tone

• Gurgling: Presence of fluids in the airway

Patient Assessment

Assessing Airway Patency

Assessment of the airway is a continuous process in emergency care.

• Ability to speak indicates airway patency

• Listen for abnormal sounds: stridor, gurgling, wheezing, snoring

• Observe chest movement and breathing patterns

• Monitor for signs of inadequate airway: inability to speak, abnormal noises, minimal chest movement

Signs of Inadequate Airway:

• No breathing or air movement

• Foreign bodies present

• Absent or uneven chest movement

• Breathing limited to abdomen

• Retractions and nasal flaring in children

Opening the Airway

Basic Life Support Positioning

Proper patient positioning is essential for airway management, especially in unconscious patients.

• Supine position is preferred for airway procedures

• Protect head and neck if spinal trauma is suspected

• Head-elevated, sniffing position aligns airway structures for improved patency

Manual Maneuvers to Open the Airway

Manual techniques are used to maintain airway patency in patients with diminished muscle control.

• Head-Tilt, Chin-Lift Maneuver: Used when no spinal injury is suspected

• Jaw-Thrust Maneuver: Used for patients with suspected spinal injury

Obstructed Airways

Foreign-Body Airway Obstruction

Obstructed airways require immediate intervention. Choking is classified as severe (complete blockage) or nonsevere (partial blockage).

• Adults: Abdominal thrusts (Heimlich maneuver)

• Infants: Back slaps and chest thrusts

• If patient becomes unconscious, begin CPR

Airway Adjuncts

Oropharyngeal and Nasopharyngeal Airways

Airway adjuncts are devices used to maintain airway patency when manual maneuvers are insufficient.

• Oropharyngeal Airway (OPA): Used in patients without gag reflex

• Nasopharyngeal Airway (NPA): Used when gag reflex is present or oral injuries exist

• Correct sizing is essential for effectiveness

Airway Adjuncts—Supraglottic Airway Devices

Advanced Airway Management

Supraglottic airways are used when basic measures fail or prolonged airway management is required.

• Devices include King airway and laryngeal mask airway

• Insertion steps vary by manufacturer

• Confirm placement with end-tidal CO2 detection

Suctioning

Clearing the Airway

Suctioning is used to remove fluids and secretions from the airway to prevent aspiration and maintain patency.

• Gravity can assist in clearing fluids by turning the patient to one side

• Suction devices include vehicle-mounted, portable, and manual units

• Rigid pharyngeal tips (Yankauer) and flexible catheters are used

• Infants are sensitive to vagal stimulation; minimize suctioning time

Special Considerations

Facial Injuries and Dental Appliances

Special situations may require additional airway management strategies.

• Frequent suctioning may be needed for facial injuries

• Dental appliances should be left in place unless they endanger the airway

• Solid obstructions require abdominal thrusts, chest thrusts, or finger sweeps

Chapter Review

The airway is essential for respiration and survival. Airway adjuncts and suctioning are critical tools for maintaining patency, especially in emergency situations. Ongoing assessment and proper technique are vital for effective airway management.

Key Questions for Review

• Name the main structures of the airway

• Explain why care for the airway is the first priority of emergency care

• Describe the signs of an inadequate airway

• Explain when the head-tilt, chin-lift maneuver should be used and when the jaw-thrust maneuver should be used

• Explain how airway adjuncts and suctioning help in airway management

Critical Thinking Scenarios

• How to proceed with a patient with gurgling sounds and inadequate breathing

• Immediate concerns when stridor is heard in a child

• Steps to correct snoring respirations in an unconscious patient

Additional info: This guide expands on brief points with academic context, definitions, and examples to ensure completeness and clarity for Anatomy & Physiology students.