Analysis of the characteristics of patients suffering from acute kidney injury following severe trauma receiving renal replacement therapy

Abstract

To analyze the characteristics of severe trauma patients with acute kidney injury (AKI) receiving renal replacement therapy (RRT), in order to look for the risk factors of AKI and the opportune time for the initiation of RRT on prognosis. A retrospective cohort study involving consecutive patients with severe trauma in emergency intensive care unit (ICU) in the Second Affiliated Hospital of Zhejiang University School of Medicine, from August 2011 to December 2014, was conducted. Inclusion criteria included age≥18 years, injury severity score (ISS) > 16, AKI receiving RRT, and the duration of hospital stay > 24 hours. The general data, the risk factors of AKI, the prognostic indicators, and the information of RRT were recorded. All patients were divided into two groups according to the prognosis, the time of onset of AKI and the initiation time of RRT. The independent risk factors for prognosis were screened by binary logistic regression analysis. Seventy-three patients were eligible for enrollment, including 48 deaths ( 65.8% ); 49 patients suffered from AKI≤48 hours after trauma (early stage group), and in 24 patients it was longer than 48 hours (late stage group). In 55 patients RRT was routinely started (routine RRT group), 18 patients underwent RRT ahead of routine criteria decided by the judgment of the attending doctor ( earlier RRT group). The main risk factors of RRT in traumatic patients with AKI were shock and sepsis, each accounted for 90.4% and 53.4%. Compared with survival group, in death group, the proportion of male patients was lower (70.8% vs. 100.0%, χ² = 7.238, P = 0.007), acute physiology and chronic health evaluation II ( APACHEII) scores were higher (23.7±5.1 vs. 14.4±3.7, t = 8.031, P < 0.001), Glasgow coma score (GCS) was lower [5.0 (3.0, 15.0) vs. 15.0 (8.0, 15.0 ), U = 320.000, P = 0.001 ], incidence of shock and sepsis was higher (97.9% vs. 76.0%, χ² = 6.755, P = 0.009; 64.6% vs. 32.0%, χ² = 7.014, P = 0.008), the rate of use of contrast medium was lower (27.1% vs. 56.0%, χ² = 5.898, P = 0.015), the time for the diagnosis of AKI post trauma was delayed [ days: 2 (1, 5) vs. 2 (1, 2), U = 762.000, P = 0.049 ], the time for the initiation of RRT post trauma was later [ days: 6.0 (3.0, 12.0) vs. 3.0 (2.0, 4.5), U = 868.500, P = 0.002 ], the recovery rate of renal function at discharge was lower (10.4% vs. 100.0%, χ² = 54.497, P < 0.001). Compared with late stage group, in early stage group, the mortality was lower (55.1% vs. 87.5%, χ² = 7.509, P = 0.006 ), and the incidence of sepsis before AKI was also lower (38.8% vs. 83.3%, χ² = 12.854, P < 0.001). Compared with routine RRT group, the recovery of renal function at discharge was better with a lower mortality rate in the earlier RRT group, but the difference was considered to be insignificant ( 55.6% vs. 36.4%, χ² = 2.064, P = 0.151; 50.0% vs. 70.9%, χ² = 2.633, P = 0.105). Logistic regression analysis showed GCS [odds ratio (OR) = 0.852, 95% confidence interval (95%CI) = 0.747-0.972, P = 0.017], shock before AKI (OR = 85.350, 95%CI = 5.682-1 282.073, P = 0.001), and sepsis before AKI (OR = 11.499, 95%CI = 2.127 - 62.161, P = 0.005) were independent risk factors for the judgment of prognosis. Shock and sepsis are the major risk factors of RRT in trauma patients with AKI. Shock, sepsis and traumatic brain injury are the independent risk factors of death. Perhaps early initiation of routine RRT cannot improve the outcome of the patients with posttraumatic renal insuficiency.