Manual Hyperinflation - Indications, Contraindications, and Procedure

What Is Manual Hyperinflation?

Manual hyperinflation is a physiotherapy technique that helps people with breathing problems. It helps to make sure the lungs get enough air and oxygen. This procedure is when a healthcare provider gives breaths to a person using a special bag or machine. They also do chest physiotherapy at the same time. By giving the patient's lungs controlled puffs of air, manual hyperinflation helps to open up collapsed parts of the lungs, make the lungs work better, and make it easier for the patient to breathe. It is often used for very sick patients in the special care part of hospitals, people using a machine to help them breathe, or those with illnesses like pneumonia, COPD, or muscle disorders. The process must be done carefully and watched closely to ensure it is safe and works well. Manual hyperinflation is also called bagging or bag squeezing.

How Does Manual Hyperinflation Work?

In manual hyperinflation, the patient is disconnected from the mechanical ventilator; then, the lungs are temporarily ventilated using a manual ventilation bag connected to oxygen.

• Firstly, a larger-than-normal volume is applied as a slow inspiratory flow (slow compression of the ventilation bag).

• Then, there is an inspiratory pause for 1 to 2 seconds.

• Followed by expiration at a high expiratory flow (rapid release of the manual resuscitator bag).

Manual hyperinflation mimics a normal cough. Airway clearance is achieved by manual hyperinflation. Since it stimulates a cough-like response, the secretions are mobilized from the smaller airways to larger airways like the trachea, where they can be removed easily.

What Is the Science Behind Manual Hyperinflation?

Airway Secretions

When the airway secretions are retained in intubated and mechanically ventilated patients, there is obstruction of the airways, resulting in atelectasis (incomplete inflation or partial collapse of the lungs).

The lung volume available for ventilation is reduced in atelectasis. In addition, sputum present for longer times in the lung also increases the growth of colonizing microorganisms.

Removing the airway secretions (sputum) frequently is mandatory in critically ill intubated and mechanically ventilated patients. Removal of sputum is done by tracheal suctioning.

In normal persons, mucociliary transport removes the sputum from smaller into the larger airways like the bronchi and trachea, which is then removed by coughing. But cough reflux is minimal or sometimes absent in sedated critically ill patients. Since they are in the supine position most of the time, retention of airway secretions in the larger airways and reduced mucociliary transport are also present.

Airway suctioning clears only the trachea since the suction catheters cannot reach the smaller airways. However, manual hyperinflation, which mimics a cough, helps in the movement of secretions and assists in its easy removal.

Lung Volume

The amount of air that moves in and out of the lungs in each respiratory cycle is called the tidal volume. The tidal volume in a normal healthy adult is 500ml per inspiration. When the manual resuscitator bag is squeezed during manual hyperinflation, the tidal volume during inspiration increases to about 1L. This increase in tidal volume and the pause after the inspiration allows the alveoli to open and increases lung compliance (expandability), reducing atelectasis. Manual hyperinflation also helps in alveoli recruitment (opening of collapsed alveoli).

What Are the Indications for Manual Hyperinflation?

• To improve atelectasis.

• To clear retained airway secretions and eliminate mucus plugging.

• To improve oxygenation and gas exchange.

• To improve respiratory mechanics.

What Are the Things to Be Assessed Before Selecting a Patient for Manual Hyperinflation?

Careful assessment of various factors is required before selecting a patient for manual hyperinflation. Some of the things to be considered are listed below.

• Respiratory status of the patient.

• Cardiovascular status, including blood pressure, arrhythmias, and many other factors, is assessed.

• Neurological status of the patient.

• The volume of fluid loss from drains.

• Presence of wheeze during auscultation.

• Previous medical and surgical history, mainly involving lungs.

• Abdominal size and pressure.

• Stability of external pacing wires, drains, etc.

• Levels of vasopressor support.

What Are the Contraindications for Manual Hyperinflation?

• Undrained pneumothorax.

• Cardiovascular instability.

• Severe bronchospasm.

• Acute head injury.

• Within 72 hours after a neurosurgery.

• Severe arterial hypotension.

• Increased levels of respiratory support.

What Are the Types of Equipment Needed for Manual Hyperinflation?

The equipment needed to perform manual hyperinflation is given below:

• 2 L oxygen reservoir bag.

• The oxygen supply turned up to 15 L per minute.

• Pressure manometer and pressure line.

• Suction equipment.

• HME bacteria filter (heat and moisture exchange filter).

• Aprons, gloves, masks, and other infection control measures.

How Is the Manual Hyperinflation Procedure Performed?

Steps Before Performing the Procedure

• A thorough assessment of the patient and all other factors regarding the procedure is done.

• The physiotherapist performing the procedure should discuss the safety and indications of the procedure with the patient's medical or surgical team.

• Consent is obtained from the patient if possible.

• Appropriate pieces of equipment needed are arranged.

• Manual ventilator bags are checked for leaks, and the valves are checked to eliminate any problems.

• The oxygen flow rate is set at 15 per minute.

• If the patient is conscious, the procedure is thoroughly explained, and the patient is reassured.

• Analgesia or sedation and the fluid balance are checked.

Steps During the Procedure

• The patient is positioned appropriately before the procedure.

• If the patient is ventilated, the ventilator is disconnected, and the manual ventilating bag is connected. If the patient is self-ventilated via tracheostomy, the oxygen supply is removed before the bag is connected.

• Firstly, small volumes are given until chest expansion can be seen.

• Slow, deep inspirations are performed with a two-handed technique.

• The manometer should be observed continuously, ensuring the pressure does not exceed 40 cmH20.

• 1.5 times the tidal volume of the ventilator is delivered.

• Another clinician assists in observation, and the physiotherapist does the manual procedures.

• Maximum inflation is done; pressure is held for two to three seconds, then released rapidly.

• Expiration must be complete before the procedure is repeated.

• The procedure is done about 6 to 8 times if the patient is stable.

• The procedure is stopped if the patient shows any signs of distress or if any side effects occur.

Who Can Perform Manual Hyperinflation?

Manual hyperinflation is done by physiotherapists who have undergone training and are competent and experienced in using the necessary equipment.

What Do Studies Say About Manual Hyperinflation?

Studies have shown that manual hyperinflation improves pulmonary compliance in post-cardiac surgery patients and patients with large atelectasis and pneumonia.

Another study found that manual hyperinflation did not reduce the length of stay in the ICU or hospital.

Conclusion.

Manual hyperinflation is a valuable technique for intubated and mechanically ventilated patients, offering major benefits in improving lung ventilation and oxygenation. Adverse effects associated with manual hyperinflation are infrequent, making it a safe option for respiratory support. Manual hyperinflation is a beneficial tool in respiratory therapies, providing clinicians with a safe and effective means to support patients with respiratory compromise.