US3667213A

US3667213A - Pulse, respiration and intravenous rate counter

Info

Publication number: US3667213A
Application number: US97077A
Authority: US
Inventors: John D Ensign
Original assignee: MEASUREMENT SCIENCE CORP
Current assignee: MEASUREMENT SCIENCE CORP
Priority date: 1970-12-11
Filing date: 1970-12-11
Publication date: 1972-06-06
Anticipated expiration: 1989-06-06

Abstract

A rate counter consisting of scales scribed on a circular chart forms the dial face of a sweep second hand stop watch, a specified number of counts of a patients pulse beats or respiratory motions or a specified number of drops from an intravenous apparatus are observed, and the stop watch is operated to stop the second had. The stopped second hand is positioned directly opposite a scale providing a direct read out of the patients pulse or respiration rate per minute or the number of cubic centimeters per hour passing from an intravenous apparatus.

Description

I i United States Patent 1151 3,667,2 1 3 Ensign 1 1 June 6, 1972 54 PULSE, RESPIRATION AND 2,831,479 4/1958 Briskier 1 28/2.05 P INTRAVENOUS RATE COUNTER 2,854,968 10/1958 Wright ..l28/2.05 P i 3,426,747 2/1969 Hennan et a1 ..128/2.05 P [72] Inventor: John D. Ensign, Brlgham C1ty, Utah [73] Assigneez Measurement Science Corporation, FOREIGN PATENTS OR APPUCATIONS Brigham City, Utah 87,668 1/1921 Switzerland ..-..128/2.05 P

[22] Filedz- Dec. 11, 1970 Primary Examiner-Richard B. Wilkinson 1 PP 97,077 Assistant Examiner-Stanley A. Wal

Attorney-B. Deon Criddle [52] U.S.Cl. ..58/l26 R, l28/2.05 P 511 1111. c1. ..G04b 19/00 1571 ABSTRACT [58] F'eld Search 1 126 127 128; A rate counter consisting of scales scribed on a circular chart 128/205 1453 forms the dial face ofa sweep second hand stop watch, a specified number of counts of a patients pulse beats or respira- [56]. Reierences C'ted tory motions or a specified number of drops from an in- UNITED STATES PATENTS travenous apparatus are observed, and the stop watch is operated to stop the second had. The stopped second hand 15 3,1 14,365 12/1963 Franz i positioned directly oppgsile a scale providing a direct read out 1.572.384 2/1926 COlVinw of the patients pulse or respiration rate per minute or the 394,666 7/1908 Klumak number of cubic centimeters per hour passing from an in- 1,476,749 12/1923 Yeomans.. .....58/l26 travenous apparatus 2,551,100 5/1951 Davis ..58/76 2,807,012 9/1959 Schwarz ..128/DlG. 13 1 Claim, 1 Drawing Figure (in-m [6 11111111111011. ll

PATENTEDJuu 6 I972 INVENTOR: JOHN D. ENSIGN.

ATTORNEY PULSE, RESPIRATION INTRAVENOUS RATE COUNTER BRIEF DESCRIPTION OF THE INVENTION 1. Field of the Invention This invention relates to apparatus for use by medical personnel and others, to determine a patients pulse or respiration rate or an intravenous flow rate.

2. Prior Art Pulse and respiration rate determinations and intravenous feed rates have long been determined by medical personnel for use in the care and treatment of the ill. The intravenous feed rate is necessary to insure that the feed apparatus is set to supply the intravenous solution at a prescribed rate. In the past, the accuracy of these calculations have been greatly dependent upon the competence of the individuals involved in making the necessary observations. Generally the calculations have been computed by counting a representative number of events occurring in a given time period and, if necessary, then multiplying the counted number of events by a factor such that the number of events per minute, or per hour, is determined. For example, a patients pulse rate is taken for seconds and the number of pulse beats counted within the 15- second period is then multiplied by four to determine the conventionally used pulse rate per minute of the patient. Similar procedures are followed for both respiration rate and intravenous flow rates with the exception that the number of drops of intravenous flow counted must also be multiplied by a pre-calculated figure representative of the volume per drop through the particular intravenous apparatus being used to determine the flow per period of time, i.e. one hour, in cubic centimeters.

' If a' counting error is made in observing the patients pulse, or respiration or if, for example, an additional number is imminently due to be counted when the measuring time is completed, and such count is not made, an error is introduced and that error is thereafter multiplied in converting the results to a commonly used figure. In the example, given a one number error in the 15 second count will quadruple the error one number per minute basis. Similarly, a small error in the counting of the number of drops passing through an intravenous apparatus could cause a large error when multiplied by both a constant time factor and a volumetric constant to determine the flow in'cubic centimeters per hour. Also, a person using this method may attempt to synchronize a particular time start with a count, i.e. may attempt to start the count as a sweep second hand moves past a 3, 6, 9 or 12 on a watch dial, thereby possibly introducing error since the starting time of the timing and of the events may not coincide.

The present invention does not include the possibilities for error that are inherent in the previously used arithmetical operations since it provides a means whereby a defined number of events can be counted and then relates elapsed time to the events to determine the rate of occurrence of the events in a commonly used ratio of events to time. This eliminates the possibility that a reference time can expire just before a count should be made and eliminates multiplication of errors. The results obtained are read directly in accordance with the position of a sweep hand with respect to a chart on the dial face of a stop watch.

SUMMARY or THE INVENTION y it is a principal object of the present invention to provide a chart for mounting as the dial face of a stop watch having a 1- minute sweep hand, and for use in combination with the sweep hand of the watch. Medical personnel can use the invention in conjunction with actual observations of a set number of events, such as the pulse beats or respiration movements, of a patient, to accurately obtain a pulse or respiration rate per minute.

Another object is to provide such a chart usable with the sweep hand of the stop watch to provide a direct read out, in cubic centimeters per hour, of intravenous flow rate, merely by operating the stop watch and counting a predetermined number of drop of the intravenous solution, regardless of whether standard or micro-drop intravenous apparatus is used.

Principal features of the present invention include a chart forming a face for a sweep hand type stop watch, which chart has a peripheral outer scale and a partial inner scale, with the scales being graduated to provide a direct read out of the number of events which would take place in one minute or the flow rate in cubic centimeters per hour, depending on the purpose for which the invention is being used.

In operating the counter, a fixed or predetermined number of events, i.e. pulse beatsor respiratory movements or a number of drops coming from an intravenous apparatus are counted with respect to time and the time required for the events to occur is set. To accomplish this, the stop watch is started when the first event is sensed, the predetermined number of events are counted and when the last counted event is sensed, the stop watch is stopped. The indice marking on the outer edge of the counter directly below the stopped sweep second hand reflects the rate of pulse or respiration per minute or the flow rate in cubic centimeters per hour. Where the flow rate per hour of the intravenous apparatus is low, i.e. below 12 cubic centimeters per hour, the inner scale is used to determine the flow rate per hour.

Difierent kinds of intravenous apparatus may have varying known drop size settings or may have variable settings, wherein a known number of drops through the apparatus makes up a cubic centimeter of intravenous solution. Even a predetermined number of very small drops, frequently referred to as microdrops, i.e. 60 drops being required to make up a cubic centimeter, can be easily and quickly counted and, the counter of the invention can be used to convert the number of drops counted and the elapsed time to the cubic centimeters per hour flow rate of the intravenous solution. Flow rates can then be changed as necessary to meet prescribed intravenous feed rates. Similarly with other standard known drop size settings, it is possible to count a predetermined number of drops within an elapsed time and to then read directly from the counter the actual volume per hour, or cubic centimeters per hour being dropped. 7

Additional objects and features of the invention will become apparent from the following detailed description and drawing, disclosing what is presently contemplated as being the best mode of the invention.

THE DRAWINGS In the drawings: The sole figure represents a top plan view of the pulse,

respiration and intravenous counter of the invention, with typical alternate positions of the sweep hand shown in dotted lines.

DETAILED DESCRIPTION Referring now to the drawing:

The pulse, respiration and intravenous counter of the invention is shown generally at 10. It includes a chart, mounted as the dial face of a conventional stop watch 11. As shown, the stop watch has start and stop buttons 11a and 1 1b and a winding means 11c but other conventional stop watches could be used. A sweep hand 12 is shown in solid lines in a straight up or 12 oclock position as the figure is viewed. The chart of the counter has a peripheral outer scale 13 and an inner scale 14 scribed thereon.

In using the counter to determine pulse in beats per minute, respiration in respiratory movements per minute, and microdrop rates in cubic centimeters per hour a count of one is started simultaneously with the operation of start button 11a to put sweep hand 12 in motion and simultaneously with sensing of the first event, i.e. pulse beat, respiratory movement, or drop fallen to a reference point. The sweep hand is allowed to continue to move until a total of 13 events (12 events after the start of the sweep hand) have occurred and, upon the sensing of the thirteenth event, button 11b is operated to stop the motion of the sweep hand. The rate per minute or, as in the case of microdrops, cubic centimeters per hour, isread directly from the indice point on the peripheral outer scale positioned directly below the stopped sweep second hand.

To calculate intravenous flow rates when the drop sizes are other than microdrop size, wherein 60 drops comprise a cubic centimeter, the intravenous apparatus is first examined to determine the number of drops coming from the apparatus required to make a cubic centimeter. Such information is precalculated and is generally prominently printed on the apparatus. If, for example, drops are required to make 1 cubic centimeter then three drops must be counted during operation of the stop watch. Thus, the stop watch is started when the first drop falls to a reference point and is stopped when the third drop reaches the assigned reference point. The number of cubic centimeters per hour being discharged from an intravenous apparatus having a 10 drop per cubic centimeter discharge setting is reflected from the indice point on the outer chart 13 directly under the stopped sweep second hand 12. in determining the volume per hour flow from an intravenous apparatus having a drop per cubic centimeter discharge setting, it is necessary to count four drops, and for apparatus having a drop per cubic centimeter discharge setting, five drops must be counted.

If the intravenous rate is to be less than 12 cubic centimeters per hourand a slow microdrop rate is used, only two drops must be counted. When the sweep hand is stopped, the cubic centimeters actually being fed per hour is read directly from the inner dial at the point where the hand intersects the dial indice.

The following are examples of showing typical operations of the present invention:

Example lln determining pulse rate, 13 pulse beats are counted. When the first beat is observed, the stop watch is started. Twelve additional beats are counted and the sweep hand is stopped when the 13th beat has been observed. Thus in one instance, the sweep second hand 12 stopped at the position shown by dotted lines 12a, with the hand pointing to numeral 60 on the peripheral outer scale 13. The numeral 60 indicated the number of pulse beats per minute of the patient. Respiration rate is determined in exactly the same way, by counting thirteen respiratory movements while starting movement of the sweep hand with the first sensed movement and stopping it after sensing of the 13th. The respiration rate per minute is then read from outer scale 13, directly beneath the sweep hand. In similar fashion, normal microdrop input rates can be checked. This is done by starting the stop watch as the first drop falls past a reference point, stopping it as the thirteenth drop moves past the reference point, and reading the cubic centimeters per hour from the scale 13 beneath the stopped sweep hand.

Example 2Where the microdrop rate is known to be slow, such flow rate is less than 12 cubic centimeters per hour, the inner scale 14 is used and only two drops need be counted. Thus, in one instance the watch was started just as the first drop fell to a reference position and was stopped when the second fell to the reference position. The sweep second hand was stopped at the position shown by dotted lines 12b and a reading of the inner scale 14 was taken beneath the sweep hand. From the reading, it was determined that the actual flow rate was 10 cubic centimeters per hour.

Example 3-As has been noted previously, to determine actual flow rate from an intravenous apparatus having a drop setting such that ten drops equals one cubic centimeter, it is necessary to count and time three drops. In one test, the stop watch was started as the first drop fell past a reference point and was stopped when the third drop fell past the reference point. The sweep hand stopped at the position shown by dotted lines 120, with the reading under the sweep hand being 30 on scale 13. Thus, the actual flow rate was thirty cubic centimeters per hour. As has been previously discussed, other counts are utilized for different drop volumes.

Although a preferred form of my invention has been disclosed, it is to be understood that the present disclosure is by way of example and that variations are possible without departing from the scope of the following claim, which subject matter] regard as my invention.

I claim:

1. A counting device comprising a stop watch having a 1-minute sweep second hand; and

a chart forming a dial face for said watch, positioned beneath the said sweep hand, said chart having a first scale thereon graduated to provide a direct read out of a plurality of pulse beats per minute, the corresponding respiration rate per minute and cubic centimeters per hour of the rate of flow through intravenous apparatus discharging micro-drops at a rate of more than 12 cubic centimeters per hour; and

a second scale graduated to allow direct reading in cubic centimeters per hour of the rate of flow through intravenous apparatus discharging microdrops at a rate of less than 12 cubic centimeters per hour, whereby stopping of the stop watch upon completion of a predetermined number of events stops the sweep hand above one of said scales.

Claims

1. A counting device comprising a stop watch having a 1-minute sweep second hand; and a chart forming a dial face for said watch, positioned beneath the said sweep hand, said chart having a first scale thereon graduated to provide a direct read out of a plurality of pulse beats per minute, the corresponding respiration rate per minute and cubic centimeters per hour of the rate of flow through intravenous apparatus discharging micro-drops at a rate of more than 12 cubic centimeters per hour; and a second scale graduated to allow direct reading in cubic centimeters per hour of the rate of flow through intravenous apparatus discharging microdrops at a rate of less than 12 cubic centimeters per hour, whereby stopping of the stop watch upon completion of a predetermined number of events stops the sweep hand above one of said scales.