Long-Term Preservation of Renal Function in Septic Shock Burn Patients Requiring Renal Replacement Therapy for Acute Kidney Injury

Abstract

Background. The real impact of septic shock-associated acute kidney injury (AKI) on the long-term renal outcome is still debated, and little is known about AKI-burn patients. In a cohort of burn survivors treated by continuous renal replacement therapy (CRRT) and sorbent technology (CPFA-CRRT), we investigated the long-term outcome of glomerular and tubular function. Methods. Out of 211 burn patients undergoing CRRT from 2001 to 2017, 45 survived, 40 completed the clinical follow-up (cumulative observation period 4067 months, median 84 months, IR 44-173), and 30 were alive on 31 December 2020. Besides creatinine and urine albumin, in the 19 patients treated with CPFA-CRRT, we determined the normalized GFR by 99mTc-DTPA (NRI-GFR) and studied glomerular and tubular urine protein markers. Results. At the follow-up endpoint, the median plasma creatinine and urine albumin were 0.99 (0.72–1.19) and 0.0 mg/dL (0.0–0.0), respectively. NRI-GFR was 103.0 mL/min (93.4–115). Four patients were diabetic, and 22/30 presented at least one risk factor for chronic disease (hypertension, dyslipidemia, and overweight). Proteinuria decreased over time, from 0.47 g/day (0.42–0.52) at 6 months to 0.134 g/day (0.09–0.17) at follow-up endpoint. Proteinuria positively correlated with the peak of plasma creatinine (r 0.6953, p 0.006) and the number of CRRT days (r 0.5650, p 0.035) during AKI course, and negatively with NRI–GFR (r −0.5545, p 0.049). In seven patients, urine protein profile showed a significant increase of glomerular marker albumin and glomerular/tubular index. Conclusions. Burn patients who experienced septic shock and AKI treated with CRRT had a long-term expectation of preserved renal function. However, these patients were more predisposed to microalbuminuria, diabetes, and the presence of risk factors for intercurrent comorbidities and chronic renal disease.

Burn-Induced Acute Kidney Injury–Two-Lane Road: From Molecular to Clinical Aspects

“…As we emphasized before, for better understanding and differentiation, burn-induced AKI is often classified as having an acute or late appearance [ 7 ]. The main incriminated etiological factors are presented in Figure 1 [ 7 , 8 , 9 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 27 , 36 , 37 , 38 , 39 , 40 ].…”

Kidney damage in burn disease. Part 2. Biochemical markers (literature review)

“…However, there is a difference between biomarkers that can be freely filtered in the glomerulus; so, any increase in their plasma level (due to damaging other renal tissues) may cause high concentrations of indicators in urine (loss of specificity), and high-molecular-weight markers that are not filtered freely and therefore are more specific when measured in urine [3]. Renal function in burn patients is usually determined by blood and urine tests, as biopsy can cause iatrogenic damage and is not commonly used in this cohort [6,7].…”

“…Burns are sometimes complicated by muscle wasting, liver failure, iatrogenic hyperhydration, and sepsis, which lower Crp levels. On the contrary, its values can increase as a result of dyshydria after trauma, during fever and immobilization [6,7,11].…”

“…Proteinuria is an indicator of the risk of developing kidney injury and the severity of burn disease [9], and it is a fairly common clinical finding in patients with severe burns and AKI associated with septic shock [6,8]. Sepsis, burn area above 30 % of the body surface, and old age are the main independent risk factors for proteinuria whose duration and nature directly correlate with the severity of the burn and septic process [6].…”

“…Proteinuria is an indicator of the risk of developing kidney injury and the severity of burn disease [9], and it is a fairly common clinical finding in patients with severe burns and AKI associated with septic shock [6,8]. Sepsis, burn area above 30 % of the body surface, and old age are the main independent risk factors for proteinuria whose duration and nature directly correlate with the severity of the burn and septic process [6]. Glomerular dysfunction is associated with increased renal excretion of high-molecularweight proteins, and tubular dysfunction is associated with increased secretion of low-molecular-weight proteins (less than 60 kDa) due to impaired tubular reabsorption and/ or degradation of these proteins (selective proteinuria).…”