Oliguria during corrective spinal surgery for idiopathic scoliosis: the role of antidiuretic hormone

Patients undergoing surgery for idiopathic scoliosis were studied to determ ine the incidence and aetiology of oliguria during the perioperative period and to evaluate the efficacy of low dose dopamine in preventing its occurr ence. Thirty patients, aged 6-18 years undergoing elective surgery were stu died. Anaesthesia was standardized. Patients were randomized to receive eit her dopamine infusion (3 mu g.kg(-1).min(-1)) (Group A) (n = 15) or dextros e infusion (control) (Group B) (n = 15). Serum and urinary electrolytes and osmolalities and serum antidiuretic hormone (ADH) concentrations were meas ured. Urine output and haemodynamic parameters were recorded. Intraoperativ e oliguria occurred in 7% of patients in Group A and 47% in Group B (P < 0. 05). Postoperative oliguria occurred in 20% of patients in Group A and 47% in Group B (P > 0.05). Urine and serum biochemical analysis revealed a stat istically significant decrease in serum sodium and osmolality (P < 0.005) a nd an increase in urinary sodium and osmolality in both groups. Serum ADH c oncentrations were increased in both groups (P < 0.05), returning to baseli ne 18 h postoperatively. We conclude that oliguria during corrective spinal surgery occurs in association with excess ADH secretion as opposed to peri operative hypovolaemia. Dopamine increases urine output in the perioperativ e period but does not prevent the release of ADH and its subsequent biochem ical effects.