The role of goal-directed therapy in the prevention of acute kidney injury after major gastrointestinal surgery: Substudy of the OPTIMISE trial.

BACKGROUND Acute kidney injury (AKI) is an important adverse outcome after major surgery. Pen-operative goal directed haemodynamic therapy (GDT) may improve outcomes by reducing complications such as AKI. OBJECTIVE To determine if GDT was associated with a reduced incidence of postoperative AKI according to specific renal biomarkers. DESIGN Prospective substudy of the OPTIMISE trial, a multicentre randomised controlled trial comparing peri-operative GDT to usual patient care. SETTING Four UK National Health Service hospitals. PATIENTS A total of 287 high-risk patients aged at least 50 years undergoing major gastrointestinal surgery. OUTCOME MEASURES The primary outcome measure was AKI defined as urinary neutrophil gelatinase-associated lipase (NGAL) at least 150 ng ml(-1) 24 and 72 h after surgery. Secondary outcomes were between-group differences in NGAL measurements and NGAL : creatinine ratios 24 and 72 h after surgery and AKI stage 2 or greater according to Kidney Disease Improving Global Outcomes (KDIGO) criteria within 30 days of surgery. RESULTS In total, 20 of 287 patients (7%) experienced postoperative AKI of KDIGO grade 2 or 3 within 30 days. The proportion of patients with urinary NGAL at least 150 ng ml(-1) 24 or 72 h after surgery was similar in the two groups [GDT 31/144 (21.5%) patients vs. usual patient care 28/143 (19.6%) patients; P= 0.88). Absolute values of urinary NGAL were also similar at 24 h (GDT 53.5 vs. usual patient care 44.1 ng ml(-1) ; P= 0.38) and 72 h (GDT 45.1 vs. usual patient care 41.1 ng ml(-1) ; P= 0.50) as were urinary NGAL : creatinine ratios at 24 h (GDT 45 vs. usual patient care 43 ng mg(-1) ; P. 0.63) and 72 h (GDT 66 vs. usual patient care 63 ng mg(-1) ; P-0.62). The incidence of KDIGO defined AKI was also similar between the groups [GDT 9/ 144 (6%) patients vs. usual patient care 11/143 (8%) patients; P- 0.80]. CONCLUSION In this trial, GDT did not reduce the incidence of AKI amongst high-risk patients undergoing major gastrointestinal surgery. This may reflect improving standards in usual patient care.