Association of rhabdomyolysis with renal outcomes and mortality in burn patients.

The contribution of rhabdomyolysis to acute kidney injury (AKI) in the context of burn injury is poorly studied. We sought to determine the impact of rhabdomyolysis on AKI (defined by the AKI Network classification), renal replacement therapy (RRT), and death. Patients admitted to the burn unit at our institution were examined. Information on sex, age, presence of inhalation injury, electrical burn, percentage TBSA burned, percentage of full-thickness burns, Injury Severity Score, and peak creatine kinase (CK) were recorded. These variables were examined via multivariate logistic regression analysis against AKI Network stage, RRT, and death. Of 1973 consecutive admissions meeting the inclusion criteria, 525 met our eligibility criteria. Log peak CK was found to be correlated with any stage of AKI (odds ratio [OR], 1.71; 95% confidence interval [CI], 1.36-2.16; P < .0001), moderate to severe AKI (OR, 2.09; 95% CI, 1.40-3.11; P = .0003), need for RRT (OR, 1.67; 95% CI, 1.16-2.40; P = .0057), and mortality (OR, 1.49; 95% CI, 1.01-2.20; P = .0441), after adjustment. Each 10-fold increase in peak CK was associated with a 70% increase in the odds of AKI, more than a 100% increase in the odds of moderate to severe AKI, a nearly 70% increase in the odds of RRT, and an almost 50% increase in the odds of mortality in patients with burn injury.

Retrospective review of serum creatinine and creatinine-based measures of estimated glomerular filtration rate in an amputee population.

A variety of equations are used to estimate glomerular filtration rate (eGFR). These formulas have never been validated in the setting of traumatic amputation. In this retrospective study involving 255 military personnel with traumatic amputations at a single outpatient center, muscle mass lost was estimated using percentage of estimated body weight lost (% EBWL). Serum creatinine (Scr) and eGFR by the Modification of Diet in Renal Disease (MDRD) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations were compared to % EBWL for each patient. The average Scr for the group studied was also compared with a cohort matched for age, sex, and race from the Third National Health and Nutrition Examination Survey (NHANES III). Percentage EBWL correlated significantly with Scr (R2 = 0.095, p < 0.0001), eGFR by MDRD (R2 = 0.077, p < 0.0001), and eGFR by CKD-EPI (R2 = 0.074, p < 0.0001). The average Scr was significantly lower than a similar population from NHANES III (0.83 +/- 0.137 mg/dL vs. 1.14 +/- 0.127 mg/dL, p < 0.0001). Percentage EBWL has a significant correlation with Scr and eGFR by both the MDRD and CKD-EPI equations. Furthermore, patients with traumatic amputation have significantly lower Scr values than the general population. Creatinine-based estimators of GFR may overestimate renal function in the setting of traumatic amputation.

The Acute Kidney Injury Network (AKIN) criteria applied in burns.

In 2007, the Acute Kidney Injury Network (AKIN) developed a modified standard for diagnosing and classifying acute kidney injury (AKI). This classification system is a modification of the previously described risk, injury, failure, loss, and end-stage (RIFLE) criteria. Among other modifications, the AKIN staging requires an absolute serum creatinine change of 0.3 mg/dl in a 48-hour period to establish the diagnosis of AKI. The purpose of this study was to apply these new criteria in the severely burned population and to compare the prevalence, stage, and mortality impact of these criteria to the RIFLE criteria. The authors performed a retrospective analysis of consecutive patients with burns admitted to their burn center for at least 24 hours from June 2003 through December 2008. Each patient was classified by both the AKIN and RIFLE criteria by three referees. Both univariate and multivariate analyses were performed to determine the impact of the various AKI stages on mortality. A total of 1973 patients met inclusion and exclusion criteria and were included in the analysis. The average age, %TBSA, injury severity score, and percent with smoke inhalation injury were 36 ± 16, 16 ± 18, 10 ± 12, and 13%, respectively. Overall, the prevalence of AKI was 33% using the AKIN criteria and 24% using the RIFLE criteria with an associated mortality of 21 and 25%, respectively. Of those meeting criteria for AKIN stage 1 (N = 434), 41% (N = 180) would have been categorized as not having AKI on the basis of the RIFLE criteria. In this cohort of patients, mortality increased by almost 8-fold when compared with those without AKI (odds ratio 7.8 [95% confidence interval (CI) 3.7-16.2], P < .0001). The area under the receiver operator characteristic curve for in-hospital mortality was significantly higher for the AKIN criteria at 0.877 (95% CI 0.848-0.906) when compared to the RIFLE criteria at 0.838 (95% CI 0.801-0.874; P = .0007). Burn patients identified as having AKI by the AKIN criteria missed by RIFLE appear to be an important cohort. On the basis of our study, AKIN criteria may be more precise and are more predictive of death than the RIFLE criteria in this population. Prospective validation is needed.

Association of AKI with adverse outcomes in burned military casualties.

BACKGROUND AND OBJECTIVES: Although associated with increased morbidity and mortality, AKI has not been systematically examined in military personnel injured from combat operations in Iraq and Afghanistan. DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS: Patients evacuated from Iraq and Afghanistan to a burn unit were examined. AKI was classified by the Acute Kidney Injury Network (AKIN) and Risk-Injury-Failure-Loss-End Stage (RIFLE) schemas. Age, sex, percentage of total body surface area burned (TBSA), percentage of full-thickness burn, inhalation injury, and injury severity score were recorded. Additional data that could be associated with poor outcomes were recorded for patients with TBSA ≥20%. Multivariate logistic regression analyses were performed to determine factors associated with morbidity and mortality. RESULTS: AKI prevalence rates by the RIFLE and AKIN criteria were 23.8% and 29.9%, respectively. After logistic regression, RIFLE categories of risk (odds ratio [OR], 15.34; 95% confidence interval [CI], 1.75-134; P=0.01), injury (OR, 46.28; 95% CI, 5.02-427; P<0.001), and failure (OR, 126; 95% CI, 13.39->999; P<0.001); AKIN-2 (OR, 23.70; 95% CI, 2.32-242; P=0.008); and AKIN-3 (OR, 130; 95% CI, 13.38->999; P<0.001) were significantly associated with death. AKIN-3, injury, and failure remained significant in the subset of patients with ≥20% TBSA. There was also a strong interaction between TBSA and the stage of AKI with respect to ventilator and intensive care unit days. CONCLUSIONS: AKI is prevalent in military casualties with burn injury and is independently associated with morbidity and mortality after adjustment for factors associated with injury severity.

Acute water intoxication during military urine drug screening.

Random mandatory urine drug screening is a routine practice in the military. The pressure to produce a urine specimen creates a temptation to consume large volumes of water, putting those individuals at risk of acute water intoxication. This occurs when the amount of water consumed exceeds the kidney's ability to excrete it, resulting in hyponatremia owing to excess amount of water compared to serum solutes. The acute drop in serum osmolality leads to cerebral edema, causing headaches, confusion, seizures, and death. There has been increasing awareness of the danger of overhydration among performance athletes, but dangers in other groups can be underappreciated. We present the case of a 37-year-old male Air Force officer who developed acute water intoxication during urine drug screening. Our case demonstrates the need for a clear Air Force policy for mandatory drug testing to minimize the risk of developing this potentially fatal condition.

Fenoldopam use in a burn intensive care unit: a retrospective study.

BACKGROUND: Fenoldopam mesylate is a highly selective dopamine-1 receptor agonist approved for the treatment of hypertensive emergencies that may have a role at low doses in preserving renal function in those at high risk for or with acute kidney injury (AKI). There is no data on low-dose fenoldopam in the burn population. The purpose of our study was to describe our use of low-dose fenoldopam (0.03-0.09 mug/kg/min) infusion in critically ill burn patients with AKI. METHODS: We performed a retrospective analysis of consecutive patients admitted to our burn intensive care unit (BICU) with severe burns from November 2005 through September 2008 who received low-dose fenoldopam. Data obtained included systolic blood pressure, serum creatinine, vasoactive medication use, urine output, and intravenous fluid. Patients on concomitant continuous renal replacement therapy were excluded. Modified inotrope score and vasopressor dependency index were calculated. One-way analysis of variance with repeated measures, Wilcoxson signed rank, and chi-square tests were used. Differences were deemed significant at p < 0.05. RESULTS: Seventy-seven patients were treated with low-dose fenoldopam out of 758 BICU admissions (10%). Twenty (26%) were AKI network (AKIN) stage 1, 14 (18%) were AKIN stage 2, 42 (55%) were AKIN stage 3, and 1 (1%) was AKIN stage 0. Serum creatinine improved over the first 24 hours and continued to improve through 48 hours (p < 0.05). There was an increase in systolic blood pressure in the first 24 hours that was sustained through 48 hours after initiation of fenoldopam (p < 0.05). Urine output increased after initiation of fenoldopam without an increase in intravenous fluid requirement (p < 0.05; p = NS). Modified inotrope score and vasopressor dependency index both decreased over 48 hours (p < 0.0001; p = 0.0012). CONCLUSIONS: These findings suggest that renal function was preserved and that urine output improved without a decrease in systolic blood pressure, increase in vasoactive medication use, or an increase in resuscitation requirement in patients treated with low-dose fenoldopam. A randomized controlled trial is required to establish the efficacy of low-dose fenoldopam in critically ill burn patients with AKI.

Chronic kidney disease management in an academic internal medicine clinic.

OBJECTIVE: We sought to evaluate the current state of chronic kidney disease (CKD) management in our academic internal medicine clinic. METHODS: A retrospective review was carried out involving all patients with laboratory evidence of CKD enrolled in our clinic. We evaluated the rate of CKD recognition as well as compliance with standard guidelines. We further subdivided our results based on physician training level, presence of diabetes, recognition of CKD, age, and race. RESULTS: Factors that significantly improved recognition and treatment of CKD in our study included presence of diabetes (p < 0.001), black race (p = 0.013), younger age (p = 0.004), and treatment by a resident physician (p = 0.009). Recognition of stage 3 CKD was associated with significant increases in urine protein analysis (p < 0.001) and nephrology consultation (p < 0.001). CONCLUSION: Chronic kidney disease remains under-recognized and undertreated despite well-publicized guidelines and widespread use of routine eGFR reporting.

Analysis of novel geometry-independent method for dialysis access pressure-flow monitoring.

BACKGROUND: End-stage renal disease (ESRD) confers a large health-care burden for the United States, and the morbidity associated with vascular access failure has stimulated research into detection of vascular access stenosis and low flow prior to thrombosis. We present data investigating the possibility of using differential pressure (DeltaP) monitoring to estimate access flow (Q) for dialysis access monitoring, with the goal of utilizing micro-electro-mechanical systems (MEMS) pressure sensors integrated within the shaft of dialysis needles. METHODS: A model of the arteriovenous graft fluid circuit was used to study the relationship between Q and the DeltaP between two dialysis needles placed 2.5-20.0 cm apart. Tubing was varied to simulate grafts with inner diameters of 4.76-7.95 mm. Data were compared with values from two steady-flow models. These results, and those from computational fluid dynamics (CFD) modeling of DeltaP as a function of needle position, were used to devise and test a method of estimating Q using DeltaP and variable dialysis pump speeds (variable flow) that diminishes dependence on geometric factors and fluid characteristics. RESULTS: In the fluid circuit model, DeltaP increased with increasing volume flow rate and with increasing needle-separation distance. A nonlinear model closely predicts this DeltaP-Q relationship (R2 > 0.98) for all graft diameters and needle-separation distances tested. CFD modeling suggested turbulent needle effects are greatest within 1 cm of the needle tip. Utilizing linear, quadratic and combined variable flow algorithms, dialysis access flow was estimated using geometry-independent models and an experimental dialysis system with the pressure sensors separated from the dialysis needle tip by distances ranging from 1 to 5 cm. Real-time DeltaP waveform data were also observed during the mock dialysis treatment, which may be useful in detecting low or reversed flow within the access. CONCLUSION: With further experimentation and needle design, this geometry-independent approach may prove to be a useful access flow monitoring method.

Human monocytic ehrlichiosis in a renal transplant patient.

Human ehrlichiosis is an emerging pathogen in immunocompromised patients, potentially leading to increased morbidity compared to immunocompetent patients. A high index of suspicion is imperative and early treatment with doxycycline can be life-saving. We report the case of an immunosuppressed renal transplant patient who was diagnosed with human monocytic ehrlichiosis and successfully treated with doxycycline.

Phosphonate lipid tubules II.

We describe a new chiral tubule-forming lipid in which the C-O-P phosphoryl linkage of the archetypal tubule-forming molecule, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine, "DC(8,9)PC", is replaced by a C-P linkage. Tubule formation with this phosphonate analogue proceeds under the same mild conditions as with DC(8,9)PC and produces similar yields, but synchrotron small-angle X-ray scattering, atomic force microscopy, and optical microscopy show the new tubules to have diameters 1.94 times as great, to be significantly shorter, and to be thinner-walled. A significant portion of the enantiomerically pure chiral phosphonate precipitate is in the form of stable open helices, and these helices are divided almost evenly between left- and right-handed members.