Intraoperative Fluid & Transfusion Therapy

* * * Neurosurgery in paediatric patients includes a wide range of procedures which may be either cranial or spinal and may be in neonates, infants and older children. Cranial surgery can be done in various positions, many of which can result in venous pooling causing cardiovascular instability. Complex cranio-facial surgery, as in syndromic craniosynostosis, can result in large replacement fluid losses as well as blood loss. Spinal surgery can range from congenital lesions such as spinal dysraphism to extensive spinal surgery as in scoliosis and these are usually performed in the prone position. These and other neurosurgical operations can be prolonged and may also be associated with large blood losses and fluid shifts. Perioperative fluid therapy in children Infants and children are sensitive to changes in volume status which can manifest as haemodynamic disturbances and reduced organ perfusion. Newborns, in particular, are more susceptible to dehydration because of the higher water content, large surface to weight area, decrease d concentrating capacity of the kidneys, greater insensible losses from thin skin and greater blood flow. There is, therefore, a very limited margin for error in calculating intraoperative fluid requirement. Fluid therapy in these children should be tailored according to the age of the patient, the type and duration of surgery, the position of the patient and on blood loss incurred during surgery, so that adverse consequences due to either inadequate or overinfusion of fluids are prevented. The goal of perioperative fluid therapy is to maintain cardiovascular stability, ensure adequate organ perfusion and maintain tissue oxygenation. For almost half a century, fluid therapy in children was based on the guidelines set by Holliday & Segar in 1957. The wisdom of this approach has recently been questioned as it was found that administration of hypotonic fluids leads to hyponatraemia, particularly in view of the fact that in certain situations such as surgical stress, non-osmotic stimuli can lead to increased secretion of anti-diuretic hormone. This has lead to severe hyponatraemia even resulting in encephalopathy and death. Perioperative fluid therapy in children has been the subject of much debate, but there has been no consensus and there are no practice guidelines till date. In a survey of perioperative fluid management, Way et al found that many responders were using unsuitable and inappropriate fluids in their clinical practice which lead to unfortunate results.