Airway Clearance Devices and Techniques

Airway Clearance Devices and Techniques

Karen A. Hardy, MD

Introduction

•Healthy children are able to clear their airway with cough and mucociliary escalator.

•Some children do not clear secretions normally and need airway clearance techniques to prevent complications. Table 113-1 specifies the types of children who need airway clearance techniques.

Signs and Symptoms of Retained Secretions

•Chronic and productive cough, wet sounding

—May be weak and obviously ineffective

—May be strong, as in patients with cystic fibrosis (CF)

•Recurrent pneumonia or atelectasis

•Respiratory distress may be clinically evident if the muscles are normal.

—Note that a hypotonic patient may not be able to show the same degree of increase in work of breathing.

•Desaturation occurs with hypoventilation.

Associated Findings

•Bulbar dysfunction: drooling, lack of gag, dysarthria

•Recurrent or chronic aspiration

•Neuromuscular diseases

•Any of the diagnoses listed in Table 113-1

Clinical Course Without Treatment

•Recurrent infections, tracheitis, bronchitis, pneumonia with fever, respiratory distress

•Symptoms worsen in weak children who can rapidly deteriorate without obvious distress

•Hypoxemia

•Repeated admissions for acute treatment and antibiotics

•End-stage lung disease with respiratory failure

Table 113-1. Who Needs Airway Clearance Techniques and Why
Anatomic or Functional Abnormality	Diagnostic Category	Pathophysiology
Mucociliary Escalator
Cilial dysfunction	Primary ciliary dyskinesia	Cilia immotile or dyskinesia
Abnormal airway surface liquid or mucous layer	Cystic fibrosis	Reduced airway surface liquid; thick and viscous mucus layer; increased inflammatory mediators; increased levels of destructive compounds (elastases, proteases)
	Pseudohypoaldo- steronism	Increased volume of airway surface liquid; intermittent airway obstruction and infection as young children, typically <6 years
	Asthma	Abnormal and increased mucus Airway edema
Cough Clearance
Respiratory muscle dysfunction
Neuromuscular disease	Duchenne muscular dystrophy	Combined respiratory motor defects with abnormal inspiratory pressure generation and/or expiratory pressure generation; bulbar dysfunction with aspiration and/or gastroesophageal reflux
	Spinal muscular atrophy type I	See Duchenne muscular dystrophy
	Spinal muscular atrophy type II	Combined respiratory motor defects with abnormal inspiratory pressure generation and/or expiratory pressure generation
	Congenital myopathies	See Duchenne muscular dystrophy
Neuromotor disease	Cerebral palsy	Inability to sense secretions in the airways or pharynx, bulbar palsies, direct aspiration, severe muscle imbalance causing scoliosis; can be associated with impaired cough, poor nasopharyngeal motor tone with subsequent upper airway obstruction and possible obstructive sleep apnea
	Phrenic nerve injuries	Profound diaphragmatic dysfunction sometimes associated with paradoxical motion
	Traumatic or postoperative head and spinal cord injury	Can damage phrenic nerve and innervation of intercostal muscles and accessory muscles, affecting the bellows function
	Meningomyelocele (spina bifida)	Bellows dysfunction and progressive scoliosis
Neurological disease	Bulbar palsy	Inability to control oral secretions and/or swallow, may include direct aspiration
Neurological disease	Encephalopathy	See bulbar palsy
Unstable airways	Airway malacia	Airways collapse with dynamic pressure changes during inspiration and/or expiration
	Tracheoesophageal fistula	See airway malacia and direct airway damage from aspiration
	VATER syndrome	See tracheoesophageal fistula
	Bronchiectasis (bronchiolitis obliterans, cystic fibrosis, immunodeficiency, primary ciliary dyskinesia, postinfectious, tuberculosis)	See airway malacia
Obstructed airways	Tracheal stenosis	Inadequate lumen for secretion clearance
Obstructed airways	Scoliosis	Airway rotational deformities (“kinking”) and muscle imbalance that can be progressive

VATER, vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, and radial and renal anomalies.

Determining Need

•Perform pulmonary function testing with maximum inspiratory pressure and maximum expiratory pressure to measure combined respiratory motor strength and ability to cough and clear secretions.

•Chest radiography can be used to look for evidence of bronchiectasis and recurrent areas of complications.

•Chest computed tomography can be used to diagnose bronchiectasis (it’s a fast procedure and often, no sedation is required).

•Sniff nasal inspiratory pressure is a less commonly used method that appears to a sensitive measure of respiratory muscle strength in patients with Duchenne muscular dystrophy.

Prescribing an Airway Clearance Technique

•Some techniques, noted herein, are easy to learn. Others are more complicated and are best taught by a pulmonologist or a specially trained respiratory therapist.

• Examples of correct technique are easily found online, from device manufacturers and major children’s hospitals, CF centers, and the Cystic Fibrosis Foundation.

—Independent methods (no equipment or assistance needed)

▪Directed cough and huff or forced exhalation maneuver (easy to learn)

▪Active cycle of breathing techniques (easy to learn)

▪Autogenic drainage (hard to learn)

—Dependent methods (personnel required)

▪Chest physical therapy or postural drainage and percussion (easy to learn)

~The American College of Chest Physicians no longer recommends chest physical therapy because alternative methods are equally or more effective. However, it remains an important technique for young infants who are unable to perform other techniques.

▪Manual cough assist (easy to learn)

—Handheld or small devices

▪Manual percussors

▪Bubble positive expiratory pressure (PEP) (easy to learn)

▪PEP valve

▪Flutter valve

▪Vibratory therapy system (eg, Acapella [Smiths Medical, Minneapolis, MN])

—Large machinery required

▪High-frequency chest compressors or “VESTs”

▪Cough-assist device ▪Intrapulmonary percussive ventilator

Independent Techniques

Huff Cough Maneuver

Huff cough or forced expiratory maneuver can help to decrease the compression of airways.

• Step 1: Inhale.

• Step 2: Hold breath for approximately 3 seconds.

• Step 3: Exhale forcefully with a slightly open glottis.

Active Cycle of Breathing Technique

•Relaxation breaths or “belly breaths”

—Step 1: The patient should lie supine to learn the techniques, then graduate to doing them in any position.

—Step 2: Place a favorite stuffed animal (for younger children) or 1 hand (for older children) on the abdomen and 1 hand on the chest to enable visual and palpable feedback.

—Step 3: Breathe in and watch the stuffed animal “take a ride,” or feel and see the hand on the abdomen move.

—Step 4: Breathe out and contract the belly muscles to push or squeeze the air out.

•Chest or thoracic expansions

—Step 1: Breathe in and feel the chest fill and rise.

—Step 2: Breathe out and see or feel the chest return to baseline.

•Combine these as a cycle of breathing.

—Perform relaxed belly breathing to start.

—Then, alternate between belly, thoracic, belly, and huff, and repeat the cycles.

•This independent skill can be mastered and then used any time in any position, although it requires attention to be the most effective.

Autogenic Drainage

•Step 1: Begin in the sitting position.

•Step 2: Breathe in via the nose (warm, filter, and humidify the air) and out via the mouth.

•Step 3: Breathe a number of breaths at each of 3 levels: small, medium, and large.

•Step 4: Suppress active coughing and move the secretions with airflow.

•Step 5: When the patient listens and feels the rattle of the moving secretions early in exhalation, it is time to move up to the next level of breathing.

Dependent Techniques

Chest Physical Therapy

•Position the patient in positions that encourage gravity drainage while clapping on the chest with either a hand or a cupped palm.

Manual Cough Assist

•The patient should be recumbent.

•Place the heel of the hand just below the xiphoid.

•Thrust from the abdomen toward the diaphragm in concert with patient efforts to cough.

PEP Techniques

Bubble PEP

Use a container with a narrow neck, such as a plastic water bottle.

• Step 1: Place a large straw into the container to rest on the bottom and still leave ≥6 inches out of the neck of the bottle.

• Step 2: Fill the bottle with liquid to 15 cm. The liquid should be potable if the child is young and he or she might drink it rather than blow it. Older children enjoy using soap and making overflowing bubbles. Place the setup into a large pan if soap is used.

•Step 3: Breathe in from room air.

•Step 4: Hold the breath for about 3 seconds.

•Step 5: Place the lips tightly around the straw.

•Step 6: Breathe out (making bubbles if using soap) for a slow count of 5–10 seconds.

•Step 7: Take a few relaxed belly breaths and repeat for a total of 10 breaths.

•Step 8: Take a break and return later. Aim for 100 breaths divided into shorter intervals during the day.

PEP Valves

•Use the same respiratory pattern as explained in the previous section, but blow into the handheld device.

•Observe that the correct pressure is achieved throughout exhalation, with the indicator included in the setup.

Oscillating PEP Devices

•High-frequency oscillations may be added to PEP. The oscillations produced by the devices throughout exhalation are passed along the airway walls and loosen the mucus.

•The flutter valve produces these oscillations with the flutter of a steel ball that sits in a cone-shaped pipe. Exhaled air pushes the ball up in the cone until air escapes and the ball reseats, producing a vibrating air flow.

•The vibratory therapy system (eg, Acapella [Smiths Medical]) and the oscillation PEP device (eg, Aerobika [Monaghan Medical, Plattsburgh, NY]) are popular devices designed to produce vibrations as patients breathe in and out.

•How to use:

—Use a mouthpiece (requires adequate muscle strength to form a tight seal) or a mask over the nose and mouth.

—Inhale for 3 seconds.

—Hold the breath.

—Exhale for 5–10 seconds while generating PEP and oscillations.

High-Frequency Chest-Wall Compression: Vests

•A number of manufacturers have devised portable machines that apply variable high-frequency oscillations directly to the chest wall via an inflated jacket. Collectively, these machines are called vests.

•Fixed pressure can be used, or variable short intervals at gradually increasing frequency can be cycled to help clear all airways.

• The personally fitted jacket is applied to the chest and inflated to avoid frictional loss of energy at the chest wall and to effectively transmit oscillations simultaneously over the entire chest wall. The inflation pressure can be adjusted, as can the oscillatory frequency.

•Vest devices move mucus from the periphery to central airways, but actual clearance is required through huff or cough to expectorate the mucus.

•Small studies and case series of patients with cerebral palsy and neuromuscular disease suggest that recurrent pneumonia in these patients can be lessened or avoided with the routine use of vests.

Cough-Assist Device

This device generates both positive and negative pressure breaths.

• Step 1: Select the patient interface. Use of a mask is common, but the cough-assist device can also be applied via adapter to an endotracheal tube or tracheostomy tube.

•Step 2: Set the inspiratory time according to the patient’s comfort or similar to the patient’s own breathing.

•Step 3: Set the exhalatory time to be longer than the inspiratory time. Encourage patients to cough, if they are able, with the suction phase of the treatment.

•Step 4: Permit a pause time for the patient to take a single breath or a few small breaths, and then proceed with the next clearance breath.

•Step 5: If the patient is unable to expectorate, suction after movement of secretions into the mouth.

Intrapulmonary Percussive Ventilator

•Positive pressure with controlled but rapid inspiratory and expiratory phases is delivered with continuous aerosol.

•A mask or mouthpiece is used (the cheeks must be supported if using a mouthpiece), and the patient breathes while the machine delivers the controlled small “breaths” over the patient’s own breathing.

•How to use:

—Step 1: Sit comfortably.

—Step 2: Load liquid (albuterol, saline, or hypertonic saline) into the aerosol chamber.

—Step 3: Place the mask over the patient’s mouth and nose, or place the mouthpiece into the patient’s mouth, and tighten or hold the patient’s cheeks.

—Step 4: Turn on the machine.

—Step 5: The patient should breathe slowly and regularly.

Upkeep and Cost Considerations

•Upkeep and cost considerations are shown in Box 113-1 and Table 113-2, respectively.

Box 113-1. General Care of Airway Clearance Therapy Equipment

Vest

• Sponge clean with mild detergent and dry dust machine .

• Use germicidal wipes .

• Clean weekly .

Positive expiratory pressure devices

• Create a water-vinegar solution that has a ratio of 1 part vinegar to 2 parts water.

• Place the mouthpiece in to soak for 20 minutes .