Administration of Intravenous Fluid
In multiplace chambers, administering fluid intravenously is not
intrinsically difficult because the intravenous fluid container and the patient are
at the same
ambient pressure. The only practical difficulty is that the air/fluid meniscus within
the drip chamber will move upward as the air volume is compressed during the compression
phase of the HBO treatment and move downward during decompression. Careful adjustment
of the fluid level in the drip chamber during decompression will prevent infusion
of air into the patient. Intravenous pumps that do not require an air-filled interface
to regulate flow can work well in multiplace chambers. Particular care must also
be taken if glass bottles are used for the fluid because large pressure gradients
across the glass wall of a bottle containing fluid and air may cause a fracture unless
the bottle is vented with a tube passing from the gas pocket within the bottle directly
to the outside. If possible, the use of glass bottles in hyperbaric chambers should
be avoided entirely.
In monoplace chambers, administration of fluids is technically
more difficult because most intravenous infusion devices must be used outside the
chamber. Therefore, fluids must be pumped in against the pressure within the chamber
(up to a 3-ATA or 1500-mm Hg pressure gradient across the chamber wall). Pumping
of fluid may be accomplished with a variety of standard intravenous fluid pumps.
It is recommended that intravenous tubing with check valves be used to prevent inadvertent
backflow of blood from the patient in the event of disconnection of the pump while
the intravenous line is unclamped. Because it is impossible to manipulate intravenous
tubing within a monoplace chamber during treatment, the tubing should be arranged
to minimize the possibility of a kink. The use of rigid arterial pressure transducer
tubing can prevent this problem.
