Airway Clearance and Mucociliary Transport

• Normal airway clearance requires a patent airway, functional mucociliary escalator, and effective cough.
• Normal clearance involves four distinct phases.

Phases of an Effective Cough

• Irritation: An abnormal stimulus sends a message to the cough center in the medulla.
• Inspiration: Reflex stimulation leads to deep inspiration.
• Compression: Forceful expiratory muscle contraction occurs against a closed glottis.
• Expulsion: The glottis opens, resulting in a violent expulsion of air from the lungs.

Abnormal Airway Clearance

• Alterations in airway patency, mucociliary function, or cough reflex can cause secretion retention, potentially leading to airway obstruction and infection.
• Failure of the cough reflex can result from ETT (endotracheal tube) cuff blocking the mucociliary escalator, anesthesia, pain, nerve damage, muscle weakness, or poor elastance (as in COPD).
• Inadequate humidification leads to the inspissation of secretions, mucous plugging, and airway obstruction.
• High FiO2 impairs mucociliary clearance directly and can cause acute tracheobronchitis.
• Certain drugs depress mucociliary transport.

Diseases Associated with Abnormal Airway Clearance

• Foreign bodies
• Tumors
• Thoracic anomalies (kyphoscoliosis)
• Asthma
• Chronic bronchitis
• Acute infection
• Cystic Fibrosis (CF)
• Musculoskeletal and neurological disorders

General Goals and Indications for Airway Clearance

• Goals include mobilizing and removing retained secretions, improving gas exchange, and decreasing the work of breathing.

Acute Conditions and Bronchial Hygiene

• Bronchial hygiene is helpful in cases of copious secretions, respiratory failure with retained secretions, acute lobar atelectasis, and hypoxemia due to lung infiltrates or V/Q abnormalities related to consolidation.
• Bronchial hygiene is not typically helpful in COPD exacerbations, pneumonia without sputum, or uncomplicated asthma.

Chronic Conditions and Bronchial Hygiene

• Helpful in CF, bronchiectasis, and chronic bronchitis with sputum production greater than 25-30 mL/day.

Prophylactic Treatment of Retained Secretions

• Includes body positioning, patient mobilization for acutely ill patients, postural drainage, percussion, vibration, and exercise.
• The goal is to maintain lung function, particularly in conditions like cystic fibrosis.

Determining the Need for Bronchial Hygiene Therapy

• Medical record review should include: history of pulmonary problems with secretions, admission for upper abdominal/thoracic surgery, advanced age, history of COPD, obesity, type and duration of procedure, type of anesthesia, presence of artificial airway, CXR findings (atelectasis/infiltrates), PFT results, and ABG values/O2 sats.
• Patient assessment should include: posture, muscle tone, cough effectiveness, sputum production, breathing pattern, physical fitness, breath sounds, vital signs, heart rate, and rhythm.

Bronchial Hygiene Methods

• Postural drainage
• Turning
• Percussion
• Vibration
• Cough techniques
• Positive airway pressure (PAP) adjuncts (PEP, vibratory PEP, high-frequency positive airway pressure devices)
• High-frequency compression/oscillation methods
• Mobilization and physical activity

Postural Drainage Therapy

• Uses gravity and mechanical energy to mobilize secretions, improve V/Q, and normalize FRC.
• Includes turning, postural drainage, percussion, and vibration.

Turning

• Rotation of the body around the longitudinal axis, either manually or with a rotational bed.
• Promotes lung expansion, improves oxygenation, and prevents retained secretions.
• Also reduces venostasis and decubitus ulcers.

Postural Drainage - Contraindications

• Absolute: Unstable spinal cord, arm traction.
• Relative: Diarrhea, agitation, increased ICPs, hypotension, dyspnea, hypoxia, cardiac arrhythmias, stabilization of ETT, vent circuit, IV, etc.

Proning

• Placing the patient face down.
• Often used with ALI (acute lung injury) to improve oxygenation.
• Increases transpulmonary pressure to help combat atelectasis and increases V/Q by shifting blood flow.

Postural Drainage Technique

• Positioning the segment to be drained in a vertical position.
• Patient must be adequately hydrated.
• Treatments scheduled every 4-6 hours as indicated, around meals and tube feedings.

Percussion and Vibration

• Application of mechanical energy to the chest wall via hands or devices.
• Aims to loosen retained secretions from the tracheobronchial tree.
• Usually performed in addition to postural drainage.
• Manual percussion involves cupped hands trapping air between the hand and chest wall, applied over the lobe or segment being drained for 3-5 minutes per segment, avoiding tender areas and bony prominences.
• Mechanical percussion/vibration delivers a consistent rate, rhythm, and impact force, but has not been proven more effective than manual techniques.

Coughing and Related Expulsion Techniques

• Bronchial hygiene moves secretions to central airways, but an effective cough is needed to clear them.

Directed Cough

• Aims to mimic the features of an effective spontaneous cough.
• Not suitable for obtunded, paralyzed, uncooperative patients, or those with severe restrictive disorders.
• Involves proper positioning (sitting, shoulders rotated inward, head/spine slightly flexed, forearms relaxed/supported, feet supported with abdominal support), breathing control (slow, deep inspiration through the nose using the diaphragm), and expiratory muscle strengthening.

Forced Expiratory Technique (FET)

• Modified directed cough, also known as "huff cough."
• Involves 1 or 2 forced expirations at middle/low lung volume with an open glottis.
• Requires high expiratory flow rate (EFR).
• More effective than directed cough, especially with postural drainage, and is useful in patients with COPD, cystic fibrosis, or bronchiectasis.

Active Cycle of Breathing

• Performed sitting or with postural drainage.
• Sequence includes relaxation/breathing control, 3-4 thoracic expansion exercises, relaxation/breathing control, 1-2 FETs, and relaxation/breathing control.

Autogenic Drainage

• Modification of directed coughing performed independently by trained patients.
• Patients sit for maximum benefit.
• Mobilizes secretions by varying lung volumes and expiratory flow.

Mechanical Insufflation-Exsufflation (MIE)

• Devices apply positive pressure of 30 to 50 cm H2O to the airway for 1 to 3 seconds, then abruptly reverse to negative pressure of -30 to -50 cm H2O.
• Treatment sessions consist of about five cycles of MIE followed by normal spontaneous breathing.
• Can be delivered via ETT, trach, or oral-nasal interface.

Positive Airway Pressure (PAP) Adjuncts

• Continuous Positive Airway Pressure (CPAP)
• Expiratory Positive Airway Pressure (EPAP)
• Positive Expiratory Pressure (PEP)

PEP (Positive Expiratory Pressure)

• Involves active expiration against a variable resistance.
• Helps move secretions into larger airways by improving ventilation of underaerated segments and preventing airway collapse during expiration.
• Should be followed by FET.
• Not suitable for children under 3 years old.

High-Frequency Chest Wall Oscillation

• The Vest applies small volumes of air to the chest wall externally.
• 30-minute sessions conducted at a frequency of 5-25 Hz, with 1-6 sessions per day.

High Frequency Compression/ Oscillation

• Flutter valve: internal application, a ball creates PEP of 10-25 cmH2O, ball "flutters" at approximately 15 Hz.
• Intrapulmonary Percussive Ventilation (IPV): delivers a series of pressurized gas minibursts at rates of 100 to 225 cycles per minute (1.6 to 3.75 Hz); manually controlled; provides constant PAP and includes a pneumatic nebulizer for aerosol delivery; treatment time is about 20 minutes.

Mobilization & Exercise

• Prevents atelectasis and postoperative pneumonia.
• Improves general fitness, self-esteem, and quality of life.
• Early mobilization is generally recommended.

Recommended Airway Clearance Techniques for Specific Conditions

• CF, ciliary dyskinesia, bronchiectasis: infants – PDPV; 3-12 years – exercise, PEP, PDPV, ACB, and HFO; >12 years – exercise, ACB, AD, PEP, PDPV, and HFO.
• Atelectasis: PDPV, PEP, ACB.
• Asthma: Exercise, PEP, PDPV, HFO.
• Neurologic abnormalities: PDPV, suction, MIE.
• Musculoskeletal weakness: PEP, MIE.

Treatment Outcome Assessment

• Monitor changes in sputum production, breath sounds, dyspnea level, vital signs, chest radiograph/ABG results, and ventilator variables.

Documentation and Follow-Up

• Chart entry should include positions used, time in positions, patient tolerance, indicators of effectiveness, and any untoward effects observed.

Explore the requirements for normal airway clearance, the function of the mucociliary escalator, and the mechanics of cough. This lesson also covers pathological conditions affecting airway patency and factors influencing mucociliary escalator effectiveness.