الفهرس 
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Abstract
Perioperative fluids are frequently required to correct fluid deficits
and compensate for blood loss before and during surgery, Major
disturbance in fluid and electrolyte balance can rapidly alter cardiovascular,
neurological and neuromuscular functions of the body. Therefore clear
understanding of normal water and electrolyte physiology, body fluids
compartments and their anesthetic implications is essential for
Perioperative care and management of hemodynamic instability.
Movement of water between compartments, osmotic pressure,
osmolarity, osmolality and tonicity should be taken in consideration.
Osmoregulation is essential mechanism to maintain cell volume, in contrast
volume regulation is brought about through changes in sodium excretion
and is essential requirement to maintain perfusion of the tissues.
An accurate method of assessing intravascular volume and preload
of the heart is essential component in successful management of patients
in the operating room. Clinical assessment of hydration status of the
patient by means of body mass, blood indicators , urine color and volume,
saliva and skin hydration also for years pressure measurement have
represented the only estimation of the volume status in the heart which of
course depends on myocardial compliance until invasive hemodynamic
monitoring appears such as pulmonary artery catheterization in 1970,
measuring important indices e.g pulmonary artery occlusion pressure,
cardiac output, mixed venous oxygen saturation which allows more
91 A Rationale Approach to Perioperative Fluid Therapy in Adult Patients
accurate determination of the hemodynamic status of critically ill patients
than is possible by clinical assessment alone.
Intrathoracic blood volume measurements (ITBV) can also reflect
accurately intravascular volume , cardiac preload and it has another
advantage is that ITBV can be repeatedly determined in spontaneously
breathing patients as well as positive pressure mechanical ventilation.
Transosphygeal echocardiography can also be used.
Volume kinetics means the volume effect of an infusion fluid and
is a central issue in fluid therapy, this usually implies how much of infused
fluid is retained in the blood stream, basic principles of kinetic analysis such
as: using an isotope such as radioiodine labeled human serum albumin to
measure the blood volume before and after the infusion. Using
physiological end points and also measuring the corresponding change in
blood hemoglobin concentration during and after the infusion.
Intravenous access establishing is indicated for Perioperative fluid
administration and it’s either peripheral intravenous access (PIVs) which
remains the safest, easiest and most common means. Veins of upper
extremities including those on dorsum of hand ,lateral forearm and
antecubital space remains the most sites of cannulation. Or central venous
access, which is indicated for administration of specific drugs,
heamodialysis, hemodynamic monitoring or inability to attain peripheral IV
line. Most common sites are internal jugular vein, subclavian vein and
occasionally femoral vein catheter.
9 2 A Rationale Approach to Perioperative Fluid Therapy in Adult Patients
Intravenous fluids: include crystalloids, colloids and oxygen carrying
plasma expanders.
Crystalloid fluids: is a solution of small water soluble molecules that
can diffuse easily across semi permeable membranes and are composed of
low molecular weight solutes either Ionic e.g (Na+Cl-)or nonionic e.g
(mannitol) they are either hypotonic, isotonic and hypertonic crystalloids .
The volume effect of crystalloids varies according to its composition.
Large volume crystalloid infusion has many drawbacks due to extra
vascular accumulation such as delayed healing of anastomosis and wounds,
inhibition of gastrointestinal motility, hypercoagulability, lung pneumonia
and respiratory problems. It also can alter acid base balance such as saline
induced acidosis.
Colloids: they are either natural such as albumin or synthetic such as
gelatins, dextrans and starches.
Oxygen carrying plasma expanders: such as hemoglobin-based
oxygen carriers (HBOCs), perfluro-carbon emulsions and liposome
encapsulated hemoglobin.
In daily practice a combination of measured lost volume and
physiological changes is used for the assessment of the fluid status in
surgical patients in order to maintain patient’s physiological function and to
replace fluid lost with appropriate intravenous fluids. Fluid lost is measured through insensible perspiration which is
approximately 10 ml/kg/day in normal conditions plus fasting, urine loss,
evaporation loss and third space loss.
Intravenous fluid therapy in special situations and the most suitable
management, type of fluid should be used in each situation such as
hypovolemic shock, trauma and burn also mentioned.
A group of recommendations and guidelines for intravenous fluid
therapy which should be taken in consideration while managing
perioperative surgical patients according to British consensus guidelines.