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A vacuum mattress is a medical device used for the immobilisation of patients, especially in case of vertebra, a pelvis or a limb trauma (especially for femur trauma), as well for hand transportation of patients on short distances (it replaces the stretcher). It was invented by Loed and Haederlé, who called it "shell" mattress (matelas coquille in French).
It consists in a sealed polymer bag (bigger than an adult human body) that encloses small polystyrene balls, with a valve, straps and handles. It is washable and invisible to X-rays.
When the mattress is under air, the ball are free and the mattress can be moulded; usually, the vacuum mattress is put on a stretcher, the patient is put on the mattress (e.g. with a scoop stretcher), and the sides of the mattress are moulded around the patient. Then, the air is pumped through the valve and the valve is closed; the atmospheric pressure presses the balls together and the mattress becomes hard and rigid; the straps are tied.
A sheet is usually put on the vacuum mattress, for three reasons:
- to protect the mattress: the casualty might have broken glass on its cloths, or a jewel that might puncture the mattress;
- to avoid the direct contact of the skin with plastic, e.g. for a sweating casualty;
- to help the patient transfer at the emergency room.
Use of the vacuum mattress
The full spine immobilisation (splint) is performed with:
- a rigid cervical collar
- a vacuum mattress
- a stretcher under it (the longitudinal stiffness of the mattress alone is not sufficient).
Preparation of the vacuum mattress
The vacuum mattress is put on a stretcher, or possibly on a long spine board. The straps are put under the mattress, along its side, so they do not reach the ground. Then, the polystyrene balls are distributed evenly through the mattress by shaking its surface: a part with less balls would be less rigid. It is also possible to concentrate the balls in a given place to make this part more rigid. Finally, a sheet is put on the mattress. The sheet is folded so it will be possible to pull it to wrap the casualty into it; the profile has an S-shape.
The team member also checks that the pump (manual or electrical) works in the right direction.
Vacuum_mattress_preparation.png
Image:Vacuum mattress preparation.png
Moulding the mattress
There are three ways to put the casualty on the vacuum mattress:
- lifting the casualty and pushing the stretcher under it; a method with five team members (four lifting and one pushing the stretcher) should be used when a spine or a pelvis trauma are suspected;
- the casualty is lifted with a scoop stretcher: the scoop stretcher is pus on the mattress and opened to release the casualty;
- the casualty is lifted on a long spine board: the board is put on the mattress, the csaualty is lifted (best with four team members) and one team member removes the board.
In all cases, the vacuum valve is up and at the feet of the casualty.
Once the casualty is on the mattress, the sheet is wrapped around him/her, and the sides of the mattress are folded against his/hers body; the top of the head must be kept clear (the mattress could retract when pumping out the air and thus compress the spine). The air is pumped until the mattress is rigid; then the valve is closed, and the traps are fastened.
Vacuum_mattress_moulding.png
Image:Vacuum mattress moulding.png
Advantages and disadvantages
Tha vacuum mattress is an alternative to the use of a long spine board. Its advantages are:
- it is comfortable;
- it is adapted to all traumas, included spine and femoral traumas;
- the victim feels secured;
- it can be used instead of a stretcher for hand transportation (with the handles, e.g. in stairs) when longitudinal rigidity is not critical, or on short distances with six team members.
It drawbacks are:
- it is relatively fragile, and becomes useless at any degradation (the vacuum requires a perfectly sealed enveloppe);
- therefore, it cannot be used alone as a scoop device (it must be put on a stretcher).
- it is heavier than a board;
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