Brattelid & Smith
432
consists of a plastic bag containing small
polystyrene foam spheres. A small manual
vacuum pump can be connected to the bag to
extract the residual air (Fig21.This process
causes the bag and its contents to stiffen in
the position in which it lay. If an animal is
placed on the bag before the air is extracted,
and the bag is pressed around the animal's
body, a mould of the animal's form will be
created when the air is removed. This
resulting 'bodyprint' gives optimal support to
the animal, since virtually the whole body is
in contact with the device (Fig3). A groove in
the contour of the bag may be made before air
extraction, to enable drainage of irrigation
Polystyrene foam (styrofoam)
Supports made of expanded polystyrene foam
are widely used in Norway for surgical pro-
cedures on fish. A V-or V-shaped cut is made
in the surface and a cloth soaked in water is
draped over the trough. This also helps to
protect the skin from the relatively rough
surface of the foam (Akhtar 1990). One large
V-shaped cleft may be used for several sizes
of fish, the residual space being filled with
moistened surgical pads (Akhtar 1990).
Hammocks of cloth or netting
Several researchers describe the use of ham-
mocks constructed from cloth or fine-
meshed netting stretched between two
water.
We propose that these vacuum bags also be
employed for fish. The surface of the bag,
after air extraction, is well-suited to irriga-
tion with water, providing a protective water
adjustable rollers (Smith &. Bell 1967, McKim
&. Syrett 1982). The length and width of the
hammock can be adjusted to fit fish of dif-
ferent sizes and shapes. These hammocks do
not, however, promote the formation of an
aqueous membrane around the fish, which
necessitates continuous irrigation with water
to avoid desiccation.
film between the fish and the bag. The fish
may easily be re-positioned during anaes-
thesia by allowing air back into the bag,
which then becomes flaccid again, and then
by re-extracting air so that it stiffens.
Vacuum bags are currently available in two
sizes (30 x 60 em and 50 x 100 cm), which are
adequate for most species used in fish
research.
A novel method: vacuum pad support
Mammalian anaesthesia, radiography and
surgery often necessitates the use of posi-
tioning equipment. In this connection, a
product has been developed (Buster vacu-
support, J0rgen Krusse A/S, Marslev,
Denmark, http://www.kruuse.com) that
Discussion
The choice of positioning device for use with
fish may be influenced both by the experi-
Fig 2 A vacuum bag and accompanying pump for air extraction
Laboratory Animals (2000) 34
Woroshzow
