Understanding Anesthesiology - The Global Regional Anesthesia ...

volume, then the surgery should be delayed, if possible,
to allow for more complete resuscitation.
Figure 8 Assessment of intra-operative fluid status
Intra-operative losses: Blood loss is usually underestimated.
It is assessed by visually inspecting blood in suction
bottles, on the drapes and on the floor. Sponges
can be weighed (1 gram = 1 cc blood), subtracting the
known dry weight of the sponge. Third space loss refers
to the loss of plasma fluid into the interstitial space
as a result of tissue trauma and can be estimated based
on the nature of the surgery:
• 2-5 cc/kg/hr for minimal surgical trauma (orthopedic
surgery)
• 5-10 cc/kg/hr for moderate surgical trauma (bowel
resection)
• 10-15 cc/kg/hr for major surgical trauma (abdominal
aortic aneurysm repair)These are all crude estimates
of fluid requirements. Adequacy of replacement
is best judged by the patient’s response to therapy.
Urine output greater than 1.0 cc/kg/hr is a reassuring
indicator of adequate organ perfusion. Hemodynamic
stability, oxygenation, pH and central venous
pressures are other indicators of volume status,
but may be affected by many other factors. Figure 8
depicts the holistic approach to assessing intraoperative
blood loss.
This figure was published in “Anesthesia for Thoracic Surgery”,
Jonathan Benumomf, Copyright Elsevier (1987).
Used with permission of Elsevier.
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