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Intermittent Positive Pressure Breathing/BIRD

12 min read

Description #

This unit is designed to help students and clinically registered physiotherapists develop a better understanding of the skills involved in the application of Intermittent Positive Pressure Breathing (IPPB) as a treatment option. After completion of this unit the participant will be competent in the safe use of IPPB, its indications and contraindications. The pre-requisites for this course are CCBSP 001-004, CCBSP 101-103. Prior to starting the CCBSP-100 series the participant will be required to complete a Knowledge and Clinical Scenario Pre-Test. After the learning unit is complete the participant will then complete the practical session, followed by the Knowledge Post Test, and finally the Clinical Scenario

Learning Objectives #

Understand the theory behind the use of IPPB/BIRD.

  • Know how to set up the IPPB/BIRD circuit.
  • Be able to explain the benefits and correct technique of IPPB/BIRD in the patient setting.
  • Know how to safely use IPPB/BIRD in the clinical setting.
  • Know the precautions/contraindications to using IPPB/BIRD as a treatment technique.
  • Be able to clinically reason when IPPB/BIRD is an appropriate treatment option and how to incorporate other Physiotherapy techniques into a treatment regime.

Introduction to IPPB #

Intermittent Positive Pressure Breathing (IPPB) was initially developed during World War Two as a means to assist pilots breathing in unpressurised cabins at high altitude (Duffy & Farley, 1992). It was first used as a treatment technique for Pulmonary disease in 1948 (Welch et al, 1980). It became highly popular for the delivery of aerosols (nebuliser’s), treatment of post operative atelectasis, decreased lung volumes, and chest infections throughout the following 3 decades and then since the 1980’s has substantially declined in popularity as a method of treatment of any respiratory issue (Duffy & Farley, 1992). 

The BIRD Respirator was developed by Forrest BIRD in the 1950’s and revolutionised the management of Respiratory illness in medicine.

Intermittent Positive Pressure Breathing is delivered at VGH using a BIRD respirator. The BIRD is connected to an Oxygen port and uses a magnetic system to cycle between delivery of air by Positive Pressure and stopping Positive Pressure air flow (on and off).  The inspiratory sensitivity, flow rate and inspiratory pressure can be adjusted, allowing the Physiotherapist to optimise treatment for each individual.

For quick reference on how to set up and use the BIRD follow this link:  How to set up IPPB circuit 

There is also a  Lecture On Demand available for your viewing at any time

Theory of IPPB #

The theory of IPPB is relatively simple. It involves the use of positive pressure to assist with the inspiratory phase of respiration. Being pressure cycled IPPB requires a negative pressure to initiate airflow. Once airflow is initiated and the set pressure is reached in the circuit (therefore also the patient) the flow shuts off and the patient exhales.

Through the use of hyperinflation, and collateral ventilation it is hypothesised that IPPB works in a way similar to Deep Breathing in the reduction of Atelectasis, and opening of collapsed or blocked airways.  It should be noted that IPPB is not a substitute and does not compare to the effect of mobilisation and activity (Denehy & Berney, 2001; Thomas & McIntosh, 1994; Ali et al, 1984).

Effects of IPPB #

As with any intervention there are always positive and negative effects. The next section will try to outline some of the effects most likely to be encountered in the clinical setting.

Positive Effects of IPPB #

Denehy & Berney (2001) summarized the literature on came up with the following general agreements regarding the physiological effects of IPPB. IPPB has been shown to improve Tidal Volumes (VT).  Since Minute Ventilation (MV) is a product of VT x Respiratory Rate (RR), MV is also increased with the use of IPPB.  An increase in MV results in blowing off a larger amount of CO2, thus improving blood gases. The metabolic cost of Hyperventilation is reduced when IPPB is used.

IPPB is also used as a method to facilitate clearance of secretions and has been shown to be effective in people with Neuromuscular Disease resulting in Respiratory Muscle Weakness (Sivasothy et al, 2001). As a result, Denehy & Berney (2001) also recommends using IPPB as a first line of treatment in Spinal Cord injury with respiratory compromise. 

No Effect or Negative Effect of IPPB #

No Effect

Over the years IPPB has been used for prophylaxis in a variety of settings. One area that IPPB has repeatedly been shown to have no effect on is the post-operative prevention of respiratory complications in Upper Abdominal Surgery (Ali et al, 1984; Thomas & McIntosh, 1994). The use of IPPB in patients with Respiratory Muscle Weakness (Spinal Cord Injury, Neuromuscular disease, Muscular Dystrophy) has not been shown to provide any immediate changes in respiratory compliance (McCool et al, 1986).

Negative Effect

However, some negative effects have been established. IPPB can reduce cardiac output through the increased intra-thoracic pressure during use (Denehy & Berney, 2001). Sivasothy et al (2001) demonstrated that the use of IPPB in the COPD population actually reduced their cough strength.

Conflicting evidence about IPPB #

Research into the use of IPPB to reduce the work of breathing or dyspnoea has drawn mixed results. On one hand it is proposed that using IPPB helps to reduce the work of breathing. Denehy & Berney (2001) reports on a paper that found a lower metabolic cost of breathing when using IPPB. Denehy & Berney (2001) then goes on to report that IPPB may help to rest patients who are short of breath and who have excess secretions. It should be noted that Denehy & Berney (2001) are reporting on the use of a relaxed, passive technique allowing the machine to do the work of inspiration compared to voluntary hyperinflation.  

In contrast to this, Mancebo et al (1995) looked into the effects of IPPB on healthy lungs with CO2 induced hyperventilation. Patients in this study were actively hyperventilating, rather that the passive hyperventilation of Denehy & Berney’s (2001) report.  Mancebo et al (1995) concluded that with an inspiratory pressure of 10cm H2O, IPPB actually increased the work of breathing. Thus suggesting that the use of IPPB in dyspnoea is actually more of a hindrance than a help to the dyspnoeic patient, and contraindicated in cases of respiratory failure. The limits of this study however, are the use of only one inspiratory pressure at a set flow rate.

One needs to take into consideration what the literature has to say, but also remember that studies are often limited and may not able to be applicable to every patient population. It is important to consider each patient individually and assess them physically rather than just looking at their numbers.

Indications for IPPB #

In Denehy & Berney’s (2001) paper they provide a reasonable summary of the indications for the use of IPPB and the literature to support it. These can be summarised to the following: 

  • Decreased lung volume (i.e. Post operatively, lung collapse)
  • Inability to deep breathe (Respiratory Muscle Weakness, Neuromuscular disease, Muscular Dystrophy)
  • Excess secretions or ineffective cough
  • Recent extubation of SCI patient

The use of IPPB in patients to aid secretions without decreased lung volumes is unfounded. The use of IPPB as prophylaxis in post operative patients is also unsupported.

How to set up IPPB circuit #

 Equipment required: 

  • BIRD
  • BIRD Circuit (non disposable)
  • Respiratory Filter x2
  • Mouth Piece (with 22mm connector) and Nose Clip
  • Mask (optional)

Set up:

  • Connect the BIRD to the wall oxygen supply
  • Place one of the Respiratory filters on the patient end of the BIRD circuit (this helps keep the circuit clean to enable using the same circuit with different patients)
  • Attach the other Respiratory filters to the BIRD on the right hand side of the machine (this keeps the machine clean to prevent spreading airborne pathogens)
  • Attach the end of the circuit to the Respiratory filter on the BIRD
  • Attach the small tube of the circuit to the small connector on the right hand side of the BIRD
  • Check the BIRD circuit is correctly working by:
  • Set the Inspiratory Trigger (left hand lever) to ~10 cmH2O
  • Set the Inspiratory Pressure (Right hand lever) to ~10-15 cmH2O
  • Set the Ensure the Air/Oxygen mix toggle is pulled fully out, and the Expiratory Timer turned off (clockwise)
  • Turn the Flow rate up to ~15-20 min-1
  • Initiate air flow (if not already functioning) by pushing in Red Toggle in the Centre of the Inspiratory Trigger lever
  • Cover the end of the BIRD Circuit with your hand and airflow should stop. (If BIRD cycles quickly then increase the Inspiratory Trigger sensitivity until machine stops cycling)
  • Attach the mouthpiece to the 22mm connector and place on the free end of the BIRD circuit with Respiratory filter
  • Alternatively, attach the Mask directly to the filter if pt unable to use the mouthpiece

Setting up IPPB with the BIRD is demonstrated below. This explanation uses the non-disposable BIRD circuit.

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Donning of Basic PPE #

Please watch the video below for a demonstration on how to Don your Basic Personal Protective Equipment, or PPE

Safety Considerations #

As with any Physiotherapeutic technique it is very important to ensure safety of the patient and of course yourself.

Some simple considerations:

  • Check that the IPPB circuit is working properly (How to set up IPPB circuit) prior to using with patients.
  • Ensure that Respiratory filters are in the circuit. This reduces the chances of respiratory infections being spread between patients.
  • Make sure you adequately explain the rationale and technique to the patient prior to beginning treatment. Some patients may find IPPB stressful if it is not explained to them properly.
  • Like any other treatment, patient compliance is paramount for both their safety and the Physiotherapist’s safety.
  • Ensuring that the patient is likely to benefit from the use of IPPB. As should be remembered by all Health Care Provider’s “above all do no harm”

Precautions #

Precautions for IPPB include but are not limited to:

  • Recent Pneumothorax
  • Rib fractures
  • Hemoptysis
  • Increased Work of Breathing
  • Inability to form a seal with lips
  • Uncontrolled pain
  • Asthma
  • Recent Lung Transplant
  • Decreased LOC
  • Presence of Tracheotomy

Contraindications to IPPB #

Contraindications to IPPB include but are not limited to:

  • Undrained Pneumothorax
  • Flail Chest
  • Inability to protect airway
  • Use of facemask in presence of facial fractures
  • Intubated patient
  • Unstable Head Injury
  • Non compliance

Techniques for Application of IPPB #

Some tips on how to improve the success of treatment when using the BIRD.

  • Encourage the patient to take deep breaths.
  • Carefully explain to the patient the point of the treatment.
  • Ensure you explain to the patient what they will experience as their lungs fill with air. Emphasise that their lungs will not explode and that the machine will stop.
  • Emphasis the need for the patient to keep their lips firmly sealed around the mouth piece of the BIRD circuit.
  • Explain how many breaths the patient will be doing with the BIRD in each session.
  • Take the nose peg off when resting.
  • If you have a difficult patient try getting another physiotherapist to help, one holding the mask and the other adjusting the BIRD as necessary.
  • Keep an eye on the patients Oxygen Saturation levels.

What to do if your patient is unable to maintain a good seal with their lips.

  • Try reducing the Flow Rate.
  • Try reducing the Inspiratory pressure until you reach a pressure they can tolerate.
  • Try swapping the mouth piece for a face mask

What if you cannot make a good seal with the mask?

  • When applying the mask, make contact with the bridge of the patients nose first, this will generally help to create good seal.
  • Try pinching the mask in half length wise to create a better fit for the patients face
  • If an NG/ND tube is in situ, ensure the tube is exiting the mask at the patient’s chin, this helps to create a better seal.
  • Air leaks usually occur around the nose, chin or corners of the mouth. Focus on creating a good seal around the nose by applying pressure to either side of the cushion at the top of the mask.

References #

  • Ali, J., Serrette, C., Wood, L.D. & Anthonisen, N.R. Effect of postoperative intermittent positive pressure breathing on lung function. Chest. (1984) 85, 192-196
  • Denehy, L. & Berny, S. The use of positive pressure devices by physiotherapists. European Respiratory Journal. (2001) 17, 821-829
  • Duffy, S.Q. & Farley, D.E. The protracted demise of medical technology: the case of intermittent positive pressure breathing. Medical Care. (1992) 30(8), 718-736
  • Mancebo, J., Isabey, H., Lorino, H., Lofaso, F., Lemaire, F. & Brochard, L. Comparative effects of pressure support ventilation and intermittent positive pressure breathing (IPPB) in non-intubated healthy subjects. European Respiratory Journal. (1995) 8, 1901-1909
  • McCool, F.D., Mayewski, R.F., Shayne, D.S., Gobson, C.J., Griggs, R.C., & Hyde, R.W. Intermittent positive pressure breathing in patients with respiratory muscle weakness. Chest. (1986) 90(4) 546-552
  • Sivasothy, P., Brown, L., Smith, I.E. & Shneerson, J.M. Effect of manually assisted cough and mechanical insufflation on cough flow of normal subjects, patients with chronic obstructive pulmonary disease (COPD), and patients with respiratory muscle weakness. Thorax. (2001) 56(4), 438-444
  • Stresemann, E. Influence of various pressure and flow rate settings of pressure-cycled respirators on minute volumes, expiratory PO2 and PCO2 of normal men during IPPB. Anesthesiology. (1967) Nov/Dec, 1096-1100
  • Thomas, J.A. & McIntosh, J.M. Are incentive spirometry, intermittent positive pressure breathing, and deep breathing exercises effective in the prevention of postoperative pulmonary complications after upper abdominal surgery? A systematic overview and meta-analysis. Physical Therapy. (1994) 74(1), 3-16
  • Welch, M.A., Shapiro, B.J., Mercurio, P., Wagner, W. & Hirayama, G. Methods of intermittent positive pressure breathing. Chest. (1980) 78(3), 463-467