The effects of balanced versus saline-based hetastarch and crystalloid solutions on acid-base and electrolyte status and gastric mucosal perfusion in elderly surgical patients.

UNLABELLED: The IV administration of sodium chloride solutions may produce a metabolic acidosis and gastrointestinal dysfunction. We designed this trial to determine whether, in elderly surgical patients, crystalloid and colloid solutions with a more physiologically balanced electrolyte formulation, such as Hartmann's solution and Hextend, can provide a superior metabolic environment and improved indices of organ perfusion when compared with saline-based fluids. Forty-seven elderly patients undergoing major surgery were randomly allocated to one of two study groups. Patients in the Balanced Fluid group received an intraoperative fluid regimen that consisted of Hartmann's solution and 6% hetastarch in balanced electrolyte and glucose injection (Hextend). Patients in the Saline group were given 0.9% sodium chloride solution and 6% hetastarch in 0.9% sodium chloride solution (Hespan). Biochemical indices and acid-base balance were determined. Gastric tonometry was used as a reflection of splanchnic perfusion. Postoperative chloride levels demonstrated a larger increase in the Saline group than the Balanced Fluid group (9.8 vs 3.3 mmol/L, P = 0.0001). Postoperative standard base excess showed a larger decline in the Saline group than the Balanced Fluid group (-5.5 vs -0.9 mmol/L, P = 0.0001). Two-thirds of patients in the Saline group, but none in the Balanced Fluid group, developed postoperative hyperchloremic metabolic acidosis (P = 0.0001). Gastric tonometry indicated a larger increase in the CO2 gap during surgery in the Saline group compared with the Balanced Fluid group (1.7 vs 0.9 kPa, P = 0.0394). In this study, the use of balanced crystalloid and colloid solutions in elderly surgical patients prevented the development of hyperchloremic metabolic acidosis and resulted in improved gastric mucosal perfusion when compared with saline-based solutions. IMPLICATIONS: This prospective, randomized, blinded trial showed that, in elderly surgical patients, the use of balanced IV solutions can prevent the development of hyperchloremic metabolic acidosis and provide better gastric mucosal perfusion compared with saline-based fluids.

Anticoagulant-induced pseudothrombocytopenia in a patient presenting for coronary artery bypass grafting.

A 73-yr-old man with severe ischaemic heart disease presented for coronary artery bypass grafting. His preoperative platelet count, obtained from an ethylene diamine tetraacetic acid (EDTA) sampling bottle, was 61 x 10(9) litre-1, but he had no history of bleeding problems. Previous platelet counts demonstrated results ranging from 16 x 10(9) litre-1 to 254 x 10(9) litre-1 with variable degrees of in vitro platelet clumping. Preoperative thrombelastography reflected a normal coagulation profile. The laboratory findings and the absence of a history of haemorrhagic complications suggested a diagnosis of EDTA-dependent pseudothrombocytopenia. We present the perioperative implications of this in vitro phenomenon and methods of detecting the functional and numerical integrity of circulating platelets.