ABSTRACT
The present review of fluid therapy studies using balanced solutions versus isotonic saline fluids (both crystalloids and colloids) aims to address recent controversy in this topic. The change to the acid-base equilibrium based on fluid selection is described. Key terms such as dilutional-hyperchloraemic acidosis (correctly used instead of dilutional acidosis or hyperchloraemic metabolic acidosis to account for both the Henderson-Hasselbalch and Stewart equations), isotonic saline and balanced solutions are defined. The review concludes that dilutional-hyperchloraemic acidosis is a side effect, mainly observed after the administration of large volumes of isotonic saline as a crystalloid. Its effect is moderate and relatively transient, and is minimised by limiting crystalloid administration through the use of colloids (in any carrier). Convincing evidence for clinically relevant adverse effects of dilutional-hyperchloraemic acidosis on renal function, coagulation, blood loss, the need for transfusion, gastrointestinal function or mortality cannot be found. In view of the long-term use of isotonic saline either as a crystalloid or as a colloid carrier, the paucity of data documenting detrimental effects of dilutional-hyperchloraemic acidosis and the limited published information on the effects of balanced solutions on outcome, we cannot currently recommend changing fluid therapy to the use of a balanced colloid preparation.
Subject(s)
Fluid Therapy , Isotonic Solutions/therapeutic use , Rehydration Solutions/therapeutic use , Water-Electrolyte Balance/physiology , Acidosis/physiopathology , Acidosis/therapy , Animals , Body Fluids/physiology , Clinical Trials as Topic/methods , Colloids/chemistry , Colloids/therapeutic use , Crystalloid Solutions , Fluid Therapy/methods , Humans , Isotonic Solutions/chemistry , Rehydration Solutions/chemistry , Sodium Chloride/chemistry , Sodium Chloride/therapeutic useABSTRACT
BACKGROUND AND OBJECTIVES: performing neuraxial anaesthesia in patients receiving antithrombotic drugs is controversial due to the increased risk of spinal epidural haematoma. Strict adherence to the recommended time intervals between the administration of anticoagulants, neuraxial blockade and the removal of catheters is thought to improve patient safety and reduce the risk of haematoma. Appropriate guidelines have been prepared by a number of national societies of anaesthesiologists, but they do not have universal acceptance. The introduction of new anticoagulants together with recent reports of stent thrombosis in patients with perioperative cessation of antiplatelet drugs have considerably broadened the issue and made revision necessary. To overcome deficiencies in content and applicability, the European Society of Anaesthesiology has taken the initiative to provide current and comprehensive guidelines for the continent as a whole. METHODS: extensive review of the literature. RESULTS AND CONCLUSIONS: in order to minimise bleeding complications during regional anaesthetic techniques, care should be taken to avoid traumatic puncture. If a bloody tap occurs when intraoperative anticoagulation is planned, postponing surgery should be considered. Alternatively, catheters can be placed the night before surgery. Regional anaesthesia in patients receiving full anticoagulation treatment continues to be contraindicated. Catheter manipulation and removal carry similar risks to insertion and the same criteria should apply. Appropriate neurological monitoring is essential during the postoperative recovery period and following catheter removal. The final decision to perform regional anaesthesia in patients receiving drugs that affect haemostasis has to be taken after careful assessment of individual risks and benefits.
