Postoperative renal management, fluid/electrolyte management and acid-base disorders

Abstract

Maintaining electrolyte, acid-base and fluid balance is the final goal of any clinical treatment in the setting of cardiac surgery and in particular with the complex clinic of congenital heart diseases. In these cases, the preservation of fluid, ionic, osmolar and acid-base balance is the sum of complex clinic evaluations and actions, taking into account the kind of surgery, the alterations due to anaesthesia, the effects of cardiopulmonary bypass, patient’s comorbidities and his own response to surgical stress. The complexity of clinical management is increased by the strict interconnection existing between electrolytes, acid-base system and fluid distributions: any change in one of them is responsible of modification of both the remainders. Moreover, the balance of each system is physiologically maintained through modification in the balance of the remainders. The character actor of these regulator mechanisms is the kidney: any alteration in renal function modifies the multifaceted homeostasis of the ‘milieu intérieur’ of the human body. The role played by kidneys is an additional problem in the clinical management of cardiac surgery patients, considering that renal impairment is one of the most frequent complications. In clinical practice, clinicians are often faced with much uncertainty that should be in part overcome through an adequate knowledge of human physiology.