Patient/invalid handling support

1. A patient support for supporting a patient, said patient support comprising:

an inflatable mattress having a plurality of rows of bladders forming at least part of a patient support surface and extending laterally across the mattress, each row having a plurality of bladders wherein each row is formed by a plurality of adjacent bladders, said bladders forming at least two zones, and each bladder in each respective zone being in fluid communication with each other bladder in said respective zone;

a pneumatic system for inflating said bladders; and

a control system, said control system including a first sensor associated with a first respective bladder of a first respective zone and a second sensor associated with a second respective bladder of a second respective zone, each of said first and second sensors including an emitter and a receiver, each emitter directing light into its respective bladder, and each receiver being adjacent its associated emitter and receiving a reflection from the light of its associated emitter directed into its respective bladder, said control system further including a reference receiver associated with one of said first and second sensors to account for decay in said emitter of said one of said first and second sensors, and said control system determining the immersion of a patient into said mattress in each of said zones based on the reflections received by said receivers, and said control system comparing the immersions at each respective zone with a defined minimum immersion for each respective zone, and when said control system determines that the immersion of one of said respective bladders deviates from its defined minimum immersion said control system adjusts the pressure in the one of said respective bladders.

2. The patient support according to claim 1 , wherein at least one of said emitters and said receivers is located outside said respective bladders.

3. The patient support according to claim 2 , wherein said emitters are located outside said respective bladders, and each of said respective bladders includes a transparent region to allow light to pass from said emitters into said respective bladders.

4. The patient support according to claim 2 , wherein both said emitters and said receivers are located outside said bladders.

5. The patient support according to claim 4 , wherein each of said first and second sensors is supported on a printed circuit board, said circuit boards being mounted at the undersides of said bladders.

6. The patient support according to claim 1 , wherein the reflections received by said receivers are used by said control system to determine the change in the volumes of the respective bladders.

7. The patient support according to claim 1 , wherein the insides of said respective bladders are each formed from a light material to minimize absorption of the light into the bladder.

8. The patient support according to claim 7 , wherein the insides of said respective bladders are white.

9. The patient support according to claim 7 , wherein the outsides of said respective bladders are opaque to filter outside ambient light.

10. The patient support according to claim 7 , wherein each of said respective bladders has an outer layer that blocks light transmission into said respective bladders from the outside ambient light.

11. The patient support according to claim 7 , wherein said bladders are adapted to block at least some of the outside ambient light.

12. The patient support according to claim 1 , wherein each of said bladders has a height (H) and a width (W) wherein H>2W.

13. The patient support according to claim 1 , wherein said top sides comprise fabric.

14. The patient support according to claim 13 , wherein said fabric is moisture permeable.

15. The patient support according to claim 1 , wherein said emitters comprises infrared emitters or optical cables emitting light.

16. The patient support according to claim 1 , wherein said control system is operable to display an immersion map of said mattress based on the detected immersions.

17. A patient support for supporting a patient, said patient support comprising:

an inflatable mattress having a plurality of rows of bladders forming at least part of a patient support surface and forming at least two zones, each row extending laterally across the mattress and having a plurality of adjacent bladders;

a pneumatic system for inflating said bladders; and

a control system, said control system including a first height sensor associated with a first respective bladder of a first respective zone, a second height sensor associated with a second respective bladder of a second respective zone, each height sensor generating a signal based on the height of its respective bladder, said control system further including a reference sensor for at least one of said height sensors to account for decay in said at least one of said height sensors, and said control system determining the immersion of a patient into said mattress in each of said zones based on the signals from said sensors, and said control system comparing the immersions at each respective zone with a defined minimum immersion for each respective zone, and when said control system determines that the immersion of one of said respective bladders deviates from its defined minimum immersion said control system adjusts the pressure in the one of said respective bladders.

18. The patient support according to claim 17 , wherein said height sensors measure reflected light or inductance.

19. The patient support according to claim 17 , wherein said control system compares the immersions to a defined maximum immersion, and said control system configured to adjust the pressure in said bladders to maintain the immersion of the patient between said predefined minimum immersion and said predefined maximum immersion.