# US 10,765,225 B2 · Occupant support with a migration sensitive bladder and method for migration detection

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- Number: US 10,765,225 B2
- Document ID: US10765225B2
- Status: Granted
- Kind: B2
- Application number: 15/597,784
- Filed: 2017-05-17
- Published: 2017-08-31
- Granted: 2020-09-08
- Earliest claimed: 2012-04-10
- Assignees: Hill-Rom Services, Inc.
- Applicants: Hill-Rom Services, Inc.
- Inventors: Christopher R. O'Keefe; Timothy J. Receveur; Aziz A. Bhai; Luke Gibson; Charles A. Lachenbruch; Rachel Williamson
- Web page: https://patentgrep.com/patent/US10765225B2

## CPC

- A47C 27/083: {with pressure control, e.g. with pressure sensors}
- A61G 7/012: raising or lowering of the whole mattress frame (A61G7/005, A61G7/008 take precedence)
- A47C 27/10: with two or more independently-fillable chambers
- A61B 5/1036: {Measuring load distribution, e.g. podologic studies}
- A61B 5/1115: {Monitoring leaving of a patient support, e.g. a bed or a wheelchair}
- A61B 5/1126: {using a particular sensing technique}
- A61B 5/6892: {Mats}
- A61G 7/002: having adjustable mattress frame
- A61G 7/015: divided into different adjustable sections, e.g. for Gatch position
- A47C 27/08: Fluid mattresses
- A61B 5/447: {specially adapted for aiding the prevention of ulcer or pressure sore development, i.e. before the ulcer or sore has developed}
- A61G 7/05769: {with inflatable chambers}
- F04C 2270/0421: Controlled or regulated
- A47C: CHAIRS; SOFAS; BEDS
- A61G: TRANSPORT, PERSONAL CONVEYANCES OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS (appliances for aiding patients or disabled persons to walk A61H3/00); OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES (embalming corpses A01N1/00)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS

## Abstract

A method for detecting occupant position change on a support surface includes establishing a rate of change of pressure in a head end test zone and in a foot end test zone, comparing the head end rate to at least one head end rate limit, comparing the foot end rate to at least one foot end rate limit, and inferring, in response to the comparing steps, whether or not occupant migration has occurred. An associated occupant support includes a frame and a mattress. The mattress includes head and foot zones each having at least one pressurizable bladder. The support also includes a controller adapted to compare a head end rate of pressure change to a head end rate limit, to compare a foot end rate of pressure change to a foot end rate limit, and to infer, in response to the comparing steps, whether or not occupant migration has occurred.

## Claims

### Claim 1

A bed comprising:
a frame;
a mattress supported by the frame, the mattress including a head zone having at least one fluid pressurizable bladder and a foot zone having at least one fluid pressurizable bladder;
a controller operable to:
compare a head end rate of pressure change to at least one head end rate limit;
compare a foot end rate of pressure change to at least one foot end rate limit; and
infer, in response to the comparing steps, whether or not occupant migration has occurred.

### Claim 2 (depends on 1)

The bed of claim 1 in which the head zone and the foot zone each include multiple bladders.

### Claim 3 (depends on 1)

The bed of claim 1 in which the head zone and the foot zone are longitudinally separated from each other by an intermediate zone.

### Claim 4 (depends on 3)

The bed of claim 3 in which one or more bladders resides in the intermediate zone, the bladders being the principal medium for supporting an occupant of the mattress in the intermediate zone.

### Claim 5 (depends on 3)

The bed of claim 3 in which a medium other than one or more bladders resides in the intermediate zone and is the principal medium for supporting an occupant of the mattress in the intermediate zone.

### Claim 6 (depends on 5)

The bed of claim 5 in which the medium is foam.

### Claim 7 (depends on 2)

The bed of claim 2 in which the head zone, the foot zone or both include a foam medium for at least partially supporting an occupant of the bed, the foam medium having a frame side and an occupant side, and in which the at least one head zone bladder is embedded in the foam medium.

### Claim 8 (depends on 2)

The bed of claim 2 in which the head zone, the foot zone or both include a foam medium for at least partially supporting an occupant of the bed, the foam medium having a frame side and an occupant side, and in which the at least one head zone bladder is exposed on the frame side of the medium.

### Claim 9 (depends on 2)

The bed of claim 2 in which the head zone, the foot zone or both include a foam medium for at least partially supporting an occupant of the bed, the foam medium having a frame side and an occupant side, and in which the at least one head zone bladder is exposed on the occupant side of the medium.

### Claim 10 (depends on 1)

The bed of claim 1 in which the at least one head end rate limit is a fast head end rate limit, and the at least one foot end rate limit is a fast foot end rate limit.

### Claim 11 (depends on 10)

The bed of claim 10 in which the inference is a positive result for occupant migration if the head end pressure rate is slower than the fast head end rate limit or if the foot end pressure rate is slower than the fast foot end rate limit.

### Claim 12 (depends on 10)

The bed of claim 10 in which the inference produces a positive result for occupant migration if the head end pressure rate is slower than the fast head end rate limit and if the foot end pressure rate is slower than the fast foot end rate limit.

### Claim 13 (depends on 10)

The bed of claim 10 including a slow head end rate limit and a slow foot end rate limit.

### Claim 14 (depends on 13)

The bed of claim 13 in which the inference is a positive result for occupant migration if the established head end pressure rate is slower than the fast head end rate limit and faster than the slow head end rate limit or if the established foot end pressure rate is slower than the fast foot end rate limit and faster than the slow foot end rate limit.

### Claim 15 (depends on 13)

The bed of claim 13 in which the inference is a positive result for occupant migration if the established head end pressure rate is slower than the fast head end rate limit and faster than the slow head end rate limit and if the established foot end pressure rate is slower than the fast foot end rate limit and faster than the slow foot end rate limit.

### Claim 16 (depends on 1)

The bed of claim 1 in which the inference produces a result with regard to occupant migration and the result is accepted as conclusive.

### Claim 17 (depends on 1)

The bed of claim 1 in which when the inference is a positive result for occupant migration, the inferring step is followed by a validation.

### Claim 18 (depends on 17)

The bed of claim 17 in which the validation includes
changing at least one of pressure in the head zone and pressure in the foot zone in response to the inferred positive result;
determining a head end pressure derivative based on the change in pressure in the head zone and/or determining a foot end pressure derivative based on the change in the pressure in the foot zone;
conducting a comparison of the pressure derivative or derivatives and an associated pressure derivative threshold; and
concluding, in response to the conducting step, whether or not occupant migration has occurred.

### Claim 19 (depends on 18)

The bed of claim 18 in which:
both the pressure in the head zone and the pressure in the foot zone are changed in response to the inferred positive result;
the determining analysis is carried out for both the head zone and the foot zone; and
the concluding analysis is positive for occupant migration if the comparison for the head zone, the comparison for the foot zone, or both indicate occupant migration.

### Claim 20 (depends on 16)

The bed of claim 16 in which the conclusion of occupant migration is followed by the controller doing any one of:
issuing an alarm;
taking an action intended to mitigate additional migration; and
taking an action to mitigate adverse effects of the migration.