Effects of differential-phase remote ischemic preconditioning intervention in laparoscopic partial nephrectomy: A single blinded, randomized controlled trial in a parallel group design.

STUDY OBJECTIVE: There are two windows of protection for remote ischemic preconditioning (RIPC), an early (ERIPC) and a late-phase (LRIPC). While ERIPC has been well studied, works on LRIPC are relatively scarce, especially for the kidneys. We aimed to compare the effects of early-phase versus late-phase RIPC in patients with laparoscopic partial nephrectomy (LPN).

DESIGN: A randomized controlled study SETTING: The Second Affiliated Hospital of Anhui Medical University, 1 May 2012 to 30 October 2013 PATIENTS: Sixty-five ASA 1 to 2 patients scheduled for LPN were located randomly to ERIPC group, LRIPC group and CON group (control).

INTERVENTIONS: Three five-minute cycles of right upper limb ischaemia and reperfusion were performed after induction of anesthesia in ERIPC group. Patients in LRIPC group received similar treatment 24h before surgery, while control patients were not subjected to preconditioning.

MEASUREMENTS: Serum neutrophil gelatinase-associated lipocalin (NGAL) and serum cystatin C (CysC) were evaluated before the induction of anesthesia (0h), 2h (2h) and 6h (6h) after surgery. Unilateral glomerular filtration rates (GFR) were assessed before and after surgery to evaluate overall renal function.

MAIN RESULTS: Serum NGAL and CysC were significantly lower in ERIPC and LRIPC groups at 2h post-operation (P<0.001), 6h post-operation (P<0.001). Additionally, The GFR were significantly lower in ERIPC and LRIPC groups than in CON group at the 3rd month after surgery (P=0.019; P<0.001). Moreover, compared to the ERIPC group, concentration of NGAL and CysC in LRIPC group decreased to a greater extent, while GFR and the percentage of decrement was significantly less in the LRIPC group (P=0.016; P<0.001).

CONCLUSIONS: Regardless of early-phase or late-phase intervention, limb remote ischemic preconditioning confers protection on renal ischemia-reperfusion injury in patients with laparoscopic partial nephrectomy, and the late-phase protection is more prominent.