Apparatus for Measuring Pulse Rate, Vital Capacity and Pulmonary Peak Flow

1. Field of the Invention

This invention relates to apparatus for measuring pulse rate and pulmonary volume and/or pulmonary peak flow, and more particularly to portable apparatus for measuring pulse rate and pulmonary peak flow during exercise.

2. Brief Description of the Prior Art

In recent decades, extensive public education campaigns have made people in the industrialized world aware of the importance of exercise in fighting cardiovascular disease. Such campaigns, coinciding with general improvements in living conditions, have made possible the very rapid spread of sports such as skiing, tennis, and jogging. An increasing number of individuals involved in such sports have shown an interest in being able to take regular measurements of the physiological parameters which will allow them to check on the proper functioning of their bodies.

From the medical point of view, a considerable number of measurements of physiological functions are necessary for precise overall diagnosis of the state of health and conditioning of an athlete. Lacking the necessary knowledge, a layman can neither take nor interpret most of these measurements. However, there are certain basic measurements that the layman can use to check his own physical condition by comparing the measurements he takes to known average values. These measures are primarily: blood pressure, pulse rate at rest or during physical exertion, pulse recovery time after physical exertion, effective pulmonary volume, i.e., the volume of that part of the lungs used to exchange respiratory gases, and pulmonary peak flow. The effective pulmonary volume is also known as the vital capacity, i.e., the total lung volume less the residual volume or volume remaining after a complete or maximal expiration. The pulmonary peak flow is the flow rate of exhaled air at its maximum or peak value, expressed in liters per second and liters per minute. Mechanical and electronic instruments for taking separate measurements of these functions are known. There are also electronic instruments for measuring blood pressure and pulse rate. Instruments designed for measuring pulmonary volume are generally bulky and cannot be used with comfort by the individual during athletic activity. Sports medicine recognizes the value of regular and repeated measurements of blood pressure and pulse (cardiac functions), as well as of pulmonary functioning. Measurements of these physiological functions during and/or immediately following sustained athletic activity is also of great value in the determination of the athlete's state of conditioning.

Therefore, a need has continued to exist for a simple and portable apparatus which will provide the athlete with measurements of pulse rate, vital capacity, and/or pulmonary peak flow during exercise.

Accordingly, it is an object of the present invention to offer the athlete the possibility of taking regular measurements of his pulse, vital capacity and/or pulmonary peak flow by means of an instrument designed so that it can be easily taken along during athletics, enabling measurements to be taken at moments of peak exertion.

A further object of the invention is to provide a portable apparatus for measuring pulse rate.

A further object is to provide a portable apparatus for measuring vital capacity.

A further object is to provide a portable apparatus for measuring both pulse rate and respiratory volume during exercise.

A further object is to provide a portable apparatus for measuring pulmonary peak flow.

Futher objects of the invention will become apparent from the description which follows.

The objects of the invention are attained by an apparatus for measuring pulse rate, respiratory volume and/or pulmonary peak flow comprising means for measuring pulse rate, means for measuring vital capacity and/or pulmonary peak flow, and a case containing both the measuring means, the case being small enough to be conveniently carried during athletic activity.

The invention will be more easily underdsood by reference to the accompanying drawings wherein:

FIG. 1 is a side elevational view of the apparatus.

FIG. 2 is a plan view of the apparatus.

FIG. 3 is a view of the apparatus taken along lines 3--3 of FIG. 2.

FIG. 4 is a schematic representation of a turbine forming part of the means for measuring vital capacity.

FIG. 5 is a pictorial representation of the electronic circuit for the vital capacity and/or pulmonary peak flow measurement function.

FIG. 6 is a pictorial representation of the electronic circuit for the pulse measurement means of the apparatus.

The illustrated apparatus comprises a metal or plastic case 1, fitted with a removable mouthpiece 2. The case is equipped with a cord 3 enabling the device to be worn around the neck. Alternatively, the case may be provided with means for fastening the apparatus to a limb of the user or to the user's clothing. The upper part of the case contains a switch 4 for preselecting the various functions of the device. The case also contains electro-optical display means 5. While any display means capable of being actuated by an electrical signal may be used, it is preferred, for reasons of compactness and light weight, that the display device be an electro-optical display device, e.g., an array of light emitting diodes or a liquid crystal display. Conveniently, the display is a multi-segment display capable of displaying one or more numerals, e.g., one or more conventional 7-segment digital electro-optical displays. The case has a space 6 for the batteries that supply power for the electronic circuits. The case is traversed from end to end by a passage 7. The lower part of passage 7 contains a spring 8 and opto-electronic means 9 for sensing the pulse rate. The upper part of passage 7 comprises a turbine 10 and a filter 13. Inside the case are spaces for two electronic circuits 11 and 12.

The turbine illustrated in FIG. 4 consists of a light plastic impeller 14 and opto-electronic sensing means 15 and 16.

Electronic circuit 11 illustrated in FIG. 5 consists of an integrated circuit 17, passive components 18, and an integrated decoding circuit 19 to decode the signal and drive the digital display.

Electronic circuit 12 illustrated in FIG. 6 consists of a commercially available micro-processor 22 for processing the pulse rate signals, passive components 18, and space for optoelectronic pulse sensing means 9.

The two circuits are supplied by three 1.5 volt batteries represented schematically by numeral 20. The electronic circuits are equipped with terminals 21. Because nearly all of its elements are combined in a single case, the device is particularly simple to use, so that a brief description of its method of use, either written or graphically represented on case 1, (e.g., immediately below switch 4), is all that is needed to enable anyone to use the device correctly.

The device is used as follows:

To measure lung volume:

The medical measurement made by the device in one embodiment is the vital capacity, i.e., pulmonary volume, excluding residual volume. In a different embodiment, through modification of the electronic circuit, the medical measurement may be FEV.sub.1, i.e., the volume of air expired in one second. In another embodiment, the medical measurement may be pulmonary peak flow.

To measure vital capacity or pulmonary peak flow, the user exhales completely into mouthpiece 2. The exhaled air enters passage 7, through filter 13 and turbine 10, causing turbine impeller 14 to turn. One of the blades of impeller 14 is colored so as to produce a signal to opto-elctronic means 15-16, which consist of a light-emitting diode (LED), e.g., an infrared light transmitter 15, and a light-sensitive receiver, e.g., an infrared-sensitive receiver 16. A digital signal is thus generated for each revolution of turbine impeller 14. This signal is transmitted to integrated circuit 17, a counting circuit which accumulates the count of revolutions of the turbine.

To determine the vital capacity, the total count of integrated circuit 17 is multiplied by a constant such that the displayed result of the total revolution count equals the volume in liters of air exhaled.

Thus processed and decoded, the signal is displayed in liters on opto-electronic digital display 5.

Alternatively, the pulmonary peak flow is measured if the integrated circuit 17 is programmed to detect the maximum counting rate, and multiply this rate by a predetermined constant to yield the value of the pulmonary peak flow in liters per second or liters per minute as desired. This value is then displayed on the digital display 5.

To measure pulse rate:

A finger is inserted into the lower part of passage 7 and held by spring 8 so that the fingertip presses lightly against opto-electronic sensor 9, consisting of an infrared light transmitter and infrared receiver. The variation of the volume of blood in the capillaries of the finger is sufficient to produce a digital signal in electro-optical sensor 9. The signal is transmitted to microprocessor 22 which computes the pulse rate (number of pulses per minute), and transmits the result to the electro-optical display.

To preselect the desired measurement, switch 4 is equipped with the necessary number of positions.

Having now fully described the invention, it will be apparent to one skilled in the art that many variations and modifications can be made without departing from the teaching and spirit thereof.