BURNS - Medicine for Mountaineering and Other Wilderness Activities - page 180

can overload the cardiovascular system and lead to heart failure, particularly in older in-
dividuals who already have reduced cardiac reserve. A fine line separates inadequate fluid
replacement and overload, and at high altitude the margin of safety is even narrower.
If the person remains confused or stuporous (in the absence of a head injury), blood
pressure is below normal, pulse is weak and rapid, and urinary output is below 50 ml per
hourafterseveralhoursoftreatment,fluidsmustbeadministeredmorerapidlyandperhaps
in larger quantities. Excessive fluid administration is indicated by a urinary output great-
er than 75 ml per hour; by subcutaneous fluid accumulation causing swelling in unburned
tissues, particularly in the legs or over the sacrum; or by pooling of fluid in the lungs pro-
ducing unusual shortness of breath. If these signs are present, the rate of fluid administra-
tion must be slowed, occasionally drastically. An indwelling urinary catheter is helpful for
monitoring urinary output.
Other Considerations
Fluidrequirementsforindividualswithburnscoveringmorethan50percentofthebody
surface should be calculated as if the burn were limited to that area. Larger fluid volumes
overload the heart if given within twenty-four hours.
A severely burned person is usually thirsty, as are most individuals in shock, but thirst
should be controlled with intravenous fluids because fluids given orally usually cause
vomiting and still greater fluid loss. (Fluids lost by vomiting must also be replaced with
Ringer's lactate or saline solution.)
Subsequent Fluid Therapy
Duringthefirsttwenty-fourhoursafteraburn,Ringer'slactateorsalinesolutionshould
be used to replace the fluid and sodium lost into the burned tissues. Thereafter, 5 percent
glucose should be used for fluid replacement. (Few expeditions would carry such fluids,
but in some popular trekking areas, such as the southern approach to Everest, fluids left
behind by expeditions are available.)
Once shock has been prevented or corrected, fluid requirements are somewhat greater
than normal but not on the enormous scale of the first day after the burn. Also, the indi-
vidual may be able to take fluids by mouth with only small (one- to twoliter) intravenous
supplements. As always, urine volume is an excellent indicator of fluid status.
By the second or third day after the burn, the blood vessels in the burned tissues begin
to recover and the fluids lost into those tissues are reabsorbed and excreted by the kidneys.
Largevolumes ofurinemaybepassed,butinthisrecoverystage fluidintake shouldnotbe
restrictedbecausetheurinaryoutputishigh.Fruitjuicesthathaveahighpotassiumcontent
may be particularly beneficial at this time.