Anaesthetists Handbook - MEDICAL EDUCATION at University ...

Miscellaneous issuessuch as Hartmann’s solution when crystalloid resuscitation orreplacement is indicated, except in hypochloraemia. When colloidsare indicated for resuscitation or replacement, low sodium loadpreparations such as Volulyte (6% hydroxyethylstarch) or Isoplex(succinylated gelatine 4%) should be considered.PrinciplesIn the absence of complications, oliguria occurring soon afteroperation is usually a normal physiological response to surgery. Thisis commonly interpreted as hypovolaemia and infusion of moresodium-containing fluids leads to expansion of the interstitial fluidvolume, causing oedema and weight gain as well as haemodilution.Solutions such as dextrose 4% / saline 0.18% and dextrose 5% areimportant sources of free water for maintenance, but should be usedwith caution as excessive amounts may cause dangeroushyponatraemia, especially in children and the elderly. These solutionsare not appropriate for resuscitation or replacement therapy except inconditions of significant free water deficit e.g. diabetes insipidus.For many surgical procedures, the assessment of fluid requirementswill be straightforward. In high risk surgical patients, intravenous fluidand inotropes should be aimed at achieving predetermined goals forcardiac output and oxygen delivery (goal directed therapy).In high risk surgical patients, fluid management should be based ongoal-directed fluid therapy whenever possible.Recommendations for preoperative fluid managementPreoperative or operative hypovolaemia should be diagnosed byflow-based measurements where possible.When crystalloid resuscitation or replacement is indicated, useHartmann’s solution. Exceptional use of 0.9% saline is indicated inhypochloraemia or diabetic ketoacidosis.When colloid resuscitation or replacement is indicated, use oneconstituted in a balanced electrolyte solution e.g. Volulyte or Isoplex.Anaesthetists Handbook January 2010 223