Blood pressure cuff

[57] ABSTRACT

An inflatable cuff for deriving blood pressure data by uniform vessel occlusion in all shape limbs to provide accurate compression comprising an inflatable bag and a pad positioned lengthwise in the cuff and in an overlying relationship within the cuff, the pad being smaller than the bag in its width dimension and distally positioned on the cuff and connected so as to anchor the cuff to the subject’s extremity and generate a substantially uniform pressure compression pattern along the extremity length under the cuff.

Claims, 2 Drawing Figures

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3.752.147

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BLOOD PRESSURE CUFF

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved inflatable blood pressure cuff for use with sphygmomanometers or similar equipment for deriving a patient’s blood pressure data.

2. Description of the Prior Art

As is well known, measurements of arterial blood pressure are commonly obtained by use of sphygmomanometers including a pneumatic cuff encircling a patient’s extremity, normally the arm, which have become standard instruments. For the most part, commercially available pneumatic cuffs have been found to work well on the upper extremities.

Major problems, however, have been incurred in those instances where the cross-section of the extremity varies significantly along short distances of the extremity length, such as commonly occurs at a patient’s thigh. Normally, with the standard cylindrical bag used on an irregular shaped or tapered leg where a crosssection along the extremity length varies significantly, there is experienced a slipping of the cuff when the bag is inflated. In addition, in utilizing a transducer under the cuff, when applied to the thigh for detecting Korotkoff sounds, arterial wall motion, or blood flow, problems are incurred due to the cuff inability to generate the uniform pressure compression pattern on the arteries, which results in poor contact between the transducer and the leg. We have found that inaccurate data is derived as a consequence of these problems, to the extent that as a whole, such an approach is frequently unreliable.

SUMMARY

The purpose of the present invention is to obviate the problems of the type enumerated above. This is accomplished by provision of a cuff comprising an inflatable bag overlying a pad forming a cushion member which is distally placed under the inflatable bag as applied to a patient, whereby in operation of the cuff the pad anchors the cuff to the leg while the bag is filled with air. The bag is filled to the desired pressure at which time the filling is terminated. Such an arrangement not only prevents slippage, but additionally allows for generation of an improved uniform pressure compression pattern and better couples a transducer to the leg which transducer is positioned under the cuff. The latter improvement provides for a better transfer of energy to and/or from the artery area being constricted by the cuff.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of the present invention.

FIG. 2 is a perspective view of a section of the cuff illustrated in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the drawings there is shown in FIG. 1 a cloth cuff generally referred to as 11, having a first compartment for containing a bladder or bag 12, and a second compartment for containing a pad 13 serving as a cushion, said cushion comprising of a suitable material such as cloth, rubber, etc.. As is illustrated, bag 12 virtually extends across the entire width of the cloth cuff 11. The pad 13, on the other hand, is positioned, in its own compartment underneath the bag so as to be centered lengthwise with the bag. Widthwise, however, the pad 13 is positioned with one edge substantially aligned with one edge of the bag 12.

A suitable aperture is provided in bag 12 for an inletoutlet air tube 14. The edge of the bag 12, along which an edge of the pad 13 is aligned, would be the distal edge of the cuff when applied about the patient’s thigh or other extremity. In the preferred embodiment, the length of the pad may be anywhere from 60 to 80 percent of the bag length and roughly anywhere from 47 to 67 percent of the bag width.

If desired, an affixing unit 15 which might comprise of a pocket, Velcro member or other suitable receiving member, could be employed at the surface of the pad 13 to secure a transducer member utilized with the cuff such as, for example, a microphone, piezoelectric crystal for ultrasonic application, strain-gauge member etc., through which transducer suitable signals could be derived for acquiring blood pressure or blood flow data.

In operation, cuff 11 is applied around an extremity such as a thigh so that the pad 13 is distally positioned. Air pressure is then applied from a suitable manual or automatic source through the tube 14 to the bag 12 which is filled to anchor the cuff having been to the extremity by pad 13 thereby holding the cuff firmly in place.

Air continues to flow until the bag 12 is brought to the desired pressure at which time the filling is terminated. This balancing in the cuff with the configuration bag-pad arrangement maintains a pressure profile in the thigh which is substantially constant along the length of the cuff so as to maintain a fairly uniform pressure compression pattern for compression of the arteries of the leg and simultaneously maintains the transducer employed in firm engagement with the leg surface.

The second stage of process, of course, is the emptying phase where air is exhausted to the atmosphere back through the tube 14. As the bag is being exhausted to the atmosphere the pad maintains the cuff anchored to the extremity to insure an improved pressure distribution of this critical stage in which blood pressure data is being collected, such data being essential for diagnostic purposes.