Deane Hillsman, M.D.
University of California at Davis, Pulmonary Department, Sacramento, California, USA

A visual biofeedback breathing pattern training system has been described at the 1995 ISARP meeting. Briefly, by menu selection of pulmonary parameters an infinite variety of breathing patterns may be generated. The display is auto corrected to a full volume-time display, and a cursor flashes across the programmed analog in the right time domain to prompt patient performance. In real time the patient sees their breathing performance and thereby has a visual biofeedback signal to correct performance.

It is theorized that the auto scale display is a particularly effective training tool as it forces the patient to focus on feeling the desired performance.

In a COPD pulmonary rehabilitation program patients were given a copy of their desired breathing analog with instructions to practice twice daily for five minutes, and to "put the picture in your mind" while practicing breathing exercises. With this minimal program most patients were following the desired breathing pattern within two to three months. Part of the program was visual instruction on lung deflation to correct air trapping and overinflation. Long term retention of the learned breathing pattern was variable, and use of the learned breathing pattern was likewise variable and anecdotally successful.

Provision of audio prompting at beginning inspiration ("beep" high pitched) and expiration ("beep" low pitched) provided a prompt which enabled patients to reproduce the desired breathing pattern without the visual prompt. It is theorized this simple audio prompt is activating the complex visual learned breathing pattern.

A portable audio and simple LED prompting device has been developed.

Conclusion: A breathing pattern training and portable activation system has been developed for COPD, and has implications for Hyperventilation Syndrome control.

At the 1995 ISARP meeting in Toronto the setup and use of a computer based visual biofeedback training system was presented, and therefore will not be elaborated on in this presentation (Copies of 1995 handout available - See: Hillsman, ISARP 1995 or http://www.sierrabiotech.com in the Biofeedback Incentive System (tm) section).

The 1995 presentation featured a version achieved in an IBM XT computer. Briefly, by menu selection an infinite variety of inspiration and expiration breathing patterns may be displayed on a computer CRT. A cursor blinks along the programmed line, and the patient attempts to match their real time performance with the programmed line.

Performance deficiencies, such as the slow inspiration rate shown in the diagram, are immediately apparent and the patient is therefore given a visual biofeedback signal to correct their training performance.

Note the three breathing patterns are identical, despite the fact that the Respiratory Rates and Tidal Volumes are very different.

This is due to the autoscaling display.

Autoscaling forces the patient to focus on internal sensing of the biofeedback experience.

It is theorized this is the reason why this type of visual biofeedback breathing training is particularly effective.

The Rescue Breathing Pattern is a cognitive universal response to acute dyspnea, or a dyspnea exacerbation of chronic dyspnea. It is a modulator response superimposed on the physiologic reflex breathing control mechanisms.

Simply stated, it is to "pump air in and out of the lungs as hard and as fast as possible" in an conscious attempt to relieve dyspnea distress.

The Rescue Breathing Pattern is as follows:

• Increased Respiratory Rate
• Increased Tidal Volume (Rate limited)
• Increased air Flow
• Forced breathing
• Focus on Inspiration
• Shortened Expiration Time

The RBP leads to Air Trapping and functional Overinflation due to:

• Necessary long time constant for expiration
• Increased dynamic bronchial compression

Overinflation places the chest wall and respiratory muscles in a position of mechanical disadvantage, and this will acutely exacerbate dyspnea.

In COPD / Emphysema / severe Asthmatic the patient must breathe:

• Slowly
• Large Tidal Volume
• Gently
• Focus on Expiration
• Increased Expiration Time

Unless these patients breathe in this manner they will develop Air Trapping and functional Overinflation.

These requirements are 180 degrees out of phase with the RBP, and therefore the Rescue Breathing Pattern in these conditions is a pathological and corrupt reflex action.

The RBP is an appropriate response in Restrictive Lung Disease.

This is the setup screen.
As the various parameters are changed by using the up or down indicators, or entering a number, the waveform changes appropriately.
Note the patient's name may be entered. Date and time are automatic.


When ready to proceed to the working displays click on the "Start" button.

Note the patient performance line contrasted to the programmed line. Inspiration is deficient and Tidal Volume was not achieved.

Note the expiration slope is too steep, i.e. expiration was too fast.

Note that inspiratory flow is almost perfect, and Tidal Volume has been achieved.

However, expiratory flow is too slow, and the patient has not exhaled back to resting Functional Residual Capacity.
This is Air Trapping.

Note that plus and minus error limits may be defined, above and below the programmed line. These limits may be adjusted.

This is a quality control means to grade patient performance, or assure data input in experimental situations.

Note the error detection (which optionally may be indicated by a beeping sound) in early inspiration.

Briefly the patient is on track, but then falls outside error limits on expiration due to slow exhalation.

Note that inspiration performance and achieved Tidal Volume are almost perfect.

Expiration performance is not as perfect, but is within the +/- 20% error limits as defined.

For research purposes with stringent control needs a +/- 10% or less error limit might be set.

These pictures are "screen dumps" in the original training system of an actual patient training session, in this case the patient's first session.

The upper record was obtained with the patient's screen blinded, in order to obtain a record of the natural breathing pattern. For comparison purposes the Tidal Volume is fixed at 1000 cc and Respiratory Rate at 10 breaths per minute.

Note the Tidal Volume of about 500 cc, and despite a prolonged expiratory phase, the patient not exhaling down to baseline FRC. This is Air Trapping.

The lower record obtained 8 minutes later shows the patient's breathing prescription, and other than for a slight delay in starting inspiration, a good match with the programmed analog breathing prescription. Tidal Volume is now about 1150 cc and lung deflation to FRC has been achieved. Annotations have been made to point out deficiencies and desired performance, and encouragement.

The patient is given a copy of their record, and with the following instructions:
Practice your breathing twice a day, for five minutes (but no more, to avoid fatigue and boredom). Sit in a comfortable chair. Relax. Concentrate. While doing your breathing exercises, put the picture in your mind.

Usually most patients demonstrate substantial alteration of their breathing pattern toward the breathing prescription within two to three months. By about the third or fourth month many spouses report patients breathing in the programmed manner while sleeping. Retention of the learned breathing pattern is variable, usually requiring two or three reinforcement sessions per year, though some patients retain their learned breathing pattern for a year or longer.

The top record shows the same patient demonstrating Air Trapping.

The bottom record shows two methods of lung deflation training.

The first technique is an approximate 25% prolongation of the programmed expiratory time. The example shows about 350 cc exhalation below the FRC. This technique is good to gradually deflate the lung over several breaths. It can be used to advantage at the onset of a dyspnea attack.

The second technique is a rescue technique for patients acutely distressed. The same respiratory timing is used, but approximately 1/2 to 2/3 of the way through expiration the patient forces expiration to a point below FRC (up to this time, patients are trained to relax as much as possible with passive exhalation). Note the expiratory forcing must be a controlled gentle action, in order to minimize the dynamic bronchial compression problem and further exacerbation of airway collapse. Done correctly, usually within 5 to 10 breaths the patient feels substantial, though not complete relief of their dyspnea attack. They can then use their regular breathing pattern to regain complete comfort over the next few minutes.

An optional audio prompt is available in the visual biofeedback training system. This consists of a "beep" (high pitched) at the beginning of inspiration, and a second "beep" (low pitched) at the beginning of expiration.

If the patient trains with both visual and audio prompts, and the visual prompt is turned off, the patient will use this simple prompt to reproduce the desired breathing pattern. This is an adjunct for patients having difficulty using, or retaining their breathing patterns.

It is theorized that patients learn complex breathing patterns from the visual biofeedback training system, and that these complex breathing patterns are activated by the simple audio prompt.

A portable prompting device is in development. A schematic design is as noted.

Inspiration and expiration LEDs activate with the appropriate "beep" sounds. A series of control switches set the appropriate timing signals, set sound level, and turn off the sound. Separately there is a manual override button which causes a 25% prolongation of the expiratory time for lung deflation. During this time the expiratory signals blink and "beeps" continuously, to focus attention on expiration.

When activated the prompting device works as noted.

The inspiratory LED activates with a high pitched "beep."

The expiratory LED activates with a low pitched "beep."

CONCLUSION: A comprehensive system to train patients in therapeutic breathing patterns, and to activate those complex learned patterns under operative conditions in the field with a simple portable device has been achieved.