Abstract. Acute renal failure increases risk of death after cardiac surgery. However, it is not known whether more subtle changes in renal function might have an impact on outcome. Thus, the association between small serum creatinine changes after surgery and mortality, independent of other established perioperative risk indicators, was analyzed. In a prospective cohort study in 4118 patients who underwent cardiac and thoracic aortic surgery, the effect of changes in serum creatinine within 48 h postoperatively on 30-d mortality was analyzed. Cox regression was used to correct for various established demographic preoperative risk indicators, intraoperative parameters, and postoperative complications. In the 2441 patients in whom serum creatinine decreased, early mortality was 2.6% in contrast to 8.9% in patients with increased postoperative serum creatinine values. Patients with large decreases (⌬Crea ϽϪ0.3 mg/dl) showed a progressively increasing 30-d mortality (16 of 199 [8%]). Mortality was lowest (47 of 2195 [2.1%]) in patients in whom serum creatinine decreased to a maximum of Ϫ0.3 mg/dl; mortality increased to 6% in patients in whom serum creatinine remained unchanged or increased up to 0.5 mg/dl. Mortality (65 of 200 [32.5%]) was highest in patients in whom creatinine increased Ն0.5 mg/dl. For all groups, increases in mortality remained significant in multivariate analyses, including postoperative renal replacement therapy. After cardiac and thoracic aortic surgery, 30-d mortality was lowest in patients with a slight postoperative decrease in serum creatinine. Any even minimal increase or profound decrease of serum creatinine was associated with a substantial decrease in survival.Acute renal failure (ARF) develops in 5 to 30% of patients who undergo cardiac surgery and is associated with a more complicated clinical course and with an excessive mortality of up to 80% (1-4). Actually, development of ARF was identified as the strongest risk factor for death with an odds ratio of 7.9 in patients who undergo cardiac surgery (1). Certainly, ARF presents an indicator for the severity and/or complicated course of disease; thus, perioperative patients with renal dysfunction are at a higher risk of dying. However, recently, is was shown convincingly that ARF acts as a risk factor for a grim prognosis independent of the severity of the underlying disease: that patients do not die with but rather from ARF (5,6).Nevertheless, it remains unknown whether not only manifest ARF but also more subtle changes in postoperative renal function might predict outcome in surgical patients. In patients with contrast-induced nephropathy, renal impairment as defined by an increase of 25% to at least 2 mg/dl in serum creatinine was associated with an odds ratio of 5.5 for death (7). Thus, the aim of the present investigation was to determine the consequences of small changes in serum creatinine within 48 h after surgery on 30-d and late mortality, independent of other established perioperative risk indicators.
Materials and MethodsBet...
BackgroundThe effects of neuromuscular electrical stimulation (NMES) in critically ill patients after cardiothoracic surgery are unknown. The objectives were to investigate whether NMES prevents loss of muscle layer thickness (MLT) and strength and to observe the time variation of MLT and strength from preoperative day to hospital discharge.MethodsIn this randomized controlled trial, 54 critically ill patients were randomized into four strata based on the SAPS II score. Patients were blinded to the intervention. In the intervention group, quadriceps muscles were electrically stimulated bilaterally from the first postoperative day until ICU discharge for a maximum of 14 days. In the control group, the electrodes were applied, but no electricity was delivered. The primary outcomes were MLT measured by ultrasonography and muscle strength evaluated with the Medical Research Council (MRC) scale. The secondary functional outcomes were average mobility level, FIM score, Timed Up and Go Test and SF-12 health survey. Additional variables of interest were grip strength and the relation between fluid balance and MLT. Linear mixed models were used to assess the effect of NMES on MLT, MRC score and grip strength.ResultsNMES had no significant effect on MLT. Patients in the NMES group regained muscle strength 4.5 times faster than patients in the control group. During the first three postoperative days, there was a positive correlation between change in MLT and cumulative fluid balance (r = 0.43, P = 0.01). At hospital discharge, all patients regained preoperative levels of muscle strength, but not of MLT. Patients did not regain their preoperative levels of average mobility (P = 0.04) and FIM score (P = 0.02) at hospital discharge, independent of group allocation.ConclusionsNMES had no effect on MLT, but was associated with a higher rate in regaining muscle strength during the ICU stay. Regression of intramuscular edema during the ICU stay interfered with measurement of changes in MLT. At hospital discharge patients had regained preoperative levels of muscle strength, but still showed residual functional disability and decreased MLT compared to pre-ICU levels in both groups.Trial registrationClinicaltrials.gov identifier NCT02391103. Registered on 7 March 2015.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1199-3) contains supplementary material, which is available to authorized users.
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