[Factors affecting in-hospital mortality in patients with sepsis: Development of a risk-adjusted model based on administrative data from German hospitals]. / Einflussgrößen auf die Krankenhaussterblichkeit bei Patienten mit Sepsis ­ Entwicklung eines risikoadjustierten Modells auf Basis der Leistungsdaten deutscher Krankenhäuser.

BACKGROUND: Inpatient administrative data from hospitals is already used nationally and internationally in many areas of internal and public quality assurance in healthcare. For sepsis as the principal condition, only a few published approaches are available for Germany. The aim of this investigation is to identify factors influencing hospital mortality by employing appropriate analytical methods in order to improve the internal quality management of sepsis. METHODS: The analysis was based on data from 754,727 DRG cases of the CLINOTEL hospital network charged in 2015. The association then included 45 hospitals of all supply levels with the exception of university hospitals (range of beds: 100 to 1,172 per hospital). Cases of sepsis were identified via the ICD codes of their principal diagnosis. Multiple logistic regression analysis was used to determine the factors influencing in-hospital lethality for this population. The model was developed using sociodemographic and other potential variables that could be derived from the DRG data set, and taking into account current literature data. The model obtained was validated with inpatient administrative data of 2016 (51 hospitals, 850,776 DRG cases). RESULTS: Following the definition of the inclusion criteria, 5,608 cases of sepsis (2016: 6,384 cases) were identified in 2015. A total of 12 significant and, over both years, stable factors were identified, including age, severity of sepsis, reason for hospital admission and various comorbidities. The AUC value of the model, as a measure of predictability, is above 0.8 (H-L test p>0.05, R2 value=0.27), which is an excellent result. CONCLUSION: The CLINOTEL model of risk adjustment for in-hospital lethality can be used to determine the mortality probability of patients with sepsis as principal diagnosis with a very high degree of accuracy, taking into account the case mix. Further studies are needed to confirm whether the model presented here will prove its value in the internal quality assurance of hospitals.

Cardiac and metabolic effects of hypothermia and inhaled hydrogen sulfide in anesthetized and ventilated mice.

OBJECTIVE: To test the hypothesis whether inhaled hydrogen sulfide amplifies the effects of deliberate hypothermia during anesthesia and mechanical ventilation as hypothermia is used to provide organ protection after brain trauma or circulatory arrest. Awake mice inhaling hydrogen sulfide exhibit reduced energy expenditure, hypothermia, and bradycardia despite unchanged systolic heart function. In rodents, anesthesia alone causes decreased metabolic rate and thus hypothermia and bradycardia. DESIGN: Prospective, controlled, randomized study. SETTING: University animal research laboratory. SUBJECTS: Male C57/B6 mice. INTERVENTIONS: After surgical instrumentation (central venous, left ventricular pressure-conductance catheters, ultrasound flow probes on the portal vein and superior mesenteric artery), normo- or hypothermic animals (core temperature = 38 degrees C and 27 degrees C) received either 100 ppm hydrogen sulfide or vehicle over 5 hrs (3 hrs hydrogen sulfide during normothermia). MEASUREMENTS AND MAIN RESULTS: During normothermia, hydrogen sulfide had no hemodynamic or metabolic effect. With or without hydrogen sulfide, hypothermia decreased blood pressure, heart rate, and cardiac output, whereas stroke volume, ejection fraction, and end-diastolic pressure remained unaffected. Myocardial and hepatic oxidative deoxyribonucleic acid damage (comet assay) and endogenous glucose production (rate of appearance of 1,2,3,4,5,6-13C6-glucose) were similar in all groups. Hypothermia comparably decreased CO2 production with or without inhaled hydrogen sulfide. During hypothermia, inhaled hydrogen sulfide increased the glucose oxidation rate (derived from the expiratory 13CO2/12CO2 ratio). This shift toward preferential carbohydrate utilization coincided with a significantly attenuated responsiveness of hepatic mitochondrial respiration to stimulation with exogenous cytochrome-c-oxidase (high-resolution respirometry). CONCLUSIONS: In anesthetized and mechanically ventilated mice, inhaled hydrogen sulfide did not amplify the systemic hemodynamic and cardiac effects of hypothermia alone. The increased aerobic glucose oxidation together with the reduced responsiveness of cellular respiration to exogenous cytochrome-c stimulation suggest that, during hypothermia, inhaled hydrogen sulfide improved the yield of mitochondrial respiration, possibly via the maintenance of mitochondrial integrity. Hence, inhaled hydrogen sulfide may offer metabolic benefit during therapeutic hypothermia.

Effect of SOD-1 over-expression on myocardial function during resuscitated murine septic shock.

PURPOSE: To test the hypothesis whether genetic over-expression of the Cu/Zn-superoxide dismutase (SOD-1) prevents the sepsis-related impairment of myocardial function and norepinephrine responsiveness in a resuscitated murine model of septic shock. METHODS: Fifteen hours after cecal ligation and puncture or sham-operation wild type, heterozygous and homozygous SOD-1 over-expressing mice were anesthetized, ventilated and instrumented with central venous and left ventricular pressure-conductance catheters, to assess heart function at 18, 21, and 24 h after CLP or sham-operation. Hydroxyethylstarch and noradrenaline (in the CLP-mice only) were infused to maintain normotensive hemodynamics. RESULTS: Fluid resuscitation and noradrenaline requirements did not differ between the mouse strains. While total myocardial SOD activity was five- and ninefold higher in the heterozygous and homozygous over-expressing animals, respectively, tissue catalase activity was not different. Anesthesia and fluid resuscitation alone caused left ventricular dilatation and a progressive fall in left ventricular end-systolic pressure and maximal systolic contraction (dp/dt (max)), while stroke volume and cardiac output increased. Due to the noradrenaline infusion heart rate, end-systolic pressure as well as dp/dt (max) and dp/dt (max) were significantly higher and relaxation time significantly lower in the CLP-mice, again without difference between the genetic strains. CONCLUSION: We conclude that neither hetero- nor homozygous SOD-1 over-expression caused a sustained improvement of the sepsis-related impairment of myocardial norepinephrine responsiveness, possibly due to the lacking increase of the tissue catalase and the mitochondrial SOD activity as well as the ongoing i.v. noradrenaline.

The effect of superoxide dismutase overexpression on hepatic gluconeogenesis and whole-body glucose oxidation during resuscitated normotensive murine septic shock.

Besides excess cytokine and NO production, enhanced oxygen radical formation was referred to contribute to the impaired hepatic gluconeogenesis during sepsis or endotoxemia. Therefore, we tested the hypothesis that genetic overexpression of the Cu/Zn-superoxide dismutase (SOD-1) may restore the sepsis-related lack of the norepinephrine-induced increase in hepatic gluconeogenesis and whole-body glucose oxidation. Anesthetized, ventilated, and instrumented wild-type control, and heterozygous and homozygous SOD-1-overexpressing mice received hydroxyethyl starch and norepinephrine to maintain normotensive hemodynamics measured at 18, 21, and 24 h after cecal ligation and puncture (CLP) or sham operation. Hepatic gluconeogenesis and whole-body glucose oxidation were calculated from liver tissue isotope and expiratory 13CO2 enrichments during continuous i.v. 1,2,3,4,5,6-13C6-glucose. Superior mesenteric artery and portal vein flows (ultrasound flow probes) and hepatic microcirculatory perfusion (Laser Doppler flowmetry) and O2 saturation (remission spectrophotometry) were comparable in the CLP and sham-operated animals, without any difference related to the mouse strain. Despite continuous i.v. norepinephrine necessary in the CLP mice, both glycemia and hepatic gluconeogenesis were similar, irrespective of the presence of sepsis and the genetic strain. Glucose oxidation rate progressively increased in the CLP groups, again without difference between the genetic strains. The surgery- and CLP-induced increase in liver cell oxidative DNA damage (tail moment in the comet assay) was less pronounced in the homozygous mice. Heterozygous nor homozygous SOD-1 overexpression did not improve the sepsis-related impairment of carbohydrate metabolism, possibly because of the lacking increase of the tissue catalase and the mitochondrial SOD activity, and the ongoing i.v. norepinephrine.

Glucose metabolism and catecholamines.

Until now, catecholamines were the drugs of choice to treat hypotension during shock states. Catecholamines, however, also have marked metabolic effects, particularly on glucose metabolism, and the degree of this metabolic response is directly related to the beta2-adrenoceptor activity of the individual compound used. Under physiologic conditions, infusing catecholamine is associated with enhanced rates of aerobic glycolysis (resulting in adenosine triphosphate production), glucose release (both from glycogenolysis and gluconeogenesis), and inhibition of insulin-mediated glycogenesis. Consequently, hyperglycemia and hyperlactatemia are the hallmarks of this metabolic response. Under pathophysiologic conditions, the metabolic effects of catecholamines are less predictable because of changes in receptor affinity and density and in drug kinetics and the metabolic capacity of the major gluconeogenic organs, both resulting from the disease per se and the ongoing treatment. It is also well-established that shock states are characterized by a hypermetabolic condition with insulin resistance and increased oxygen demands, which coincide with both compromised tissue microcirculatory perfusion and mitochondrial dysfunction. This, in turn, causes impaired glucose utilization and may lead to inadequate glucose supply and, ultimately, metabolic failure. Based on the landmark studies on intensive insulin use, a crucial role is currently attributed to glucose homeostasis. This article reviews the effects of the various catecholamines on glucose utilization, both under physiologic conditions, as well as during shock states. Because, to date (to our knowledge), no patient data are available, results from relevant animal experiments are discussed. In addition, potential strategies are outlined to influence the catecholamine-induced effects on glucose homeostasis.

The effect of iNOS deletion on hepatic gluconeogenesis in hyperdynamic murine septic shock.

OBJECTIVE: To investigate the role of the inducible nitric oxide synthase activation-induced excess nitric oxide formation on the rate of hepatic glucose production during fully resuscitated murine septic shock. DESIGN: Prospective, controlled, randomized animal study. SETTING: University animal research laboratory. SUBJECTS: Male C57Bl/6 and B6.129P2-Nos2(tm1Lau)/J (iNOS-/-) mice. INTERVENTIONS: Fifteen hours after cecal ligation and puncture, anesthetized, mechanically ventilated and instrumented mice (wild-type controls, n = 13; iNOS-/-, n = 12; wild-type mice receiving 5 mg.kg(-1) i.p. of the selective iNOS inhibitor GW274150 immediately after cecal ligation and puncture, n =8) received continuous i.v. hydroxyethylstarch and norepinephrine to achieve normotensive and hyperdynamic hemodynamics. MEASUREMENTS AND RESULTS: Measurements were recorded 18, 21 and 24 h after cecal ligation and puncture. Liver microcirculatory perfusion and capillary hemoglobin O2 saturation (laser Doppler flowmetry and remission spectrophotometry) were well maintained in all groups. Despite significantly lower norepinephrine doses required to achieve the hemodynamic targets, the rate of hepatic glucose production (gas chromatography--mass spectrometry measurements of tissue isotope enrichment during continuous i.v. 1,2,3,4,5,6-13C6-glucose infusion) at 24 h after cecal ligation and puncture was significantly higher in both iNOS-/- and GW274150-treated mice, which was concomitant with a significantly higher hepatic phosphoenolpyruvate carboxykinase activity (spectrophotometry) in these animals. CONCLUSIONS: In normotensive, hyperdynamic septic shock, both pharmacologic and genetic deletion of the inducible nitric oxide synthase allowed maintenance of hepatic glucose production, most likely due to maintained activity of the key regulatory enzyme of gluconeogenesis, phosphoenolpyruvate carboxykinase.

Role of inducible nitric oxide synthase in the reduced responsiveness of the myocardium to catecholamines in a hyperdynamic, murine model of septic shock.

OBJECTIVES: Excess nitric oxide production is a key mediator of hypotension and catecholamine-resistance in septic shock. Although nitric oxide synthase blockade has been shown to restore hemodynamics, conflicting results on myocardial function were reported. Inducible nitric oxide synthase (iNOS) knockout (iNOS-/-) mice showed improved heart function, but these results were obtained during hypodynamic shock characterized by reduced cardiac output. Therefore, we investigated heart function and catecholamine responsiveness in a clinically relevant, murine model of cecal ligation and puncture (CLP)-induced septic shock. DESIGN: Prospective, controlled, randomized animal study. SETTING: University animal research laboratory. SUBJECTS: Male C57Bl/6 wild-type and iNOS-/- mice. INTERVENTIONS: Fifteen hours after CLP, three groups of mice (wild-type controls, n = 9; iNOS-/-, n = 12; and wild-type mice receiving 5 mg x kg(-1) intraperitoneally of the selective iNOS inhibitor GW274150 immediately after CLP, n = 8) were anesthetized, mechanically ventilated, and instrumented (central venous and left ventricular pressure-conductance catheter). Measurements were recorded 18, 21, and 24 hrs post-CLP. Hydroxyethylstarch and norepinephrine were infused to achieve normotensive and hyperdynamic hemodynamics. MEASUREMENTS AND MAIN RESULTS: There was no intergroup difference in mean arterial pressure, stroke volume, and left ventricular ejection fraction. Norepinephrine doses required to achieve the hemodynamic targets were lower in GW274150 (p < .001 vs. controls) and even further reduced in iNOS-/- mice (p < .001 vs. controls, p < .001 vs. GW274150). In the control group, the higher norepinephrine doses resulted in significantly higher heart rates and consequently cardiac output, maximal contraction, and relaxation than in the GW274150 and iNOS-/- animals. Left ventricular end-diastolic volume was also significantly higher in the controls than in the GW274150 and iNOS-/- mice, whereas left ventricular end-diastolic pressure did not differ. CONCLUSIONS: Our results confirm septic shock-related impaired left ventricular function. Genetic iNOS deletion and pharmacologic iNOS blockade enhanced cardiac norepinephrine responsiveness due to improved systolic function. In contrast, iNOS inhibition seemed to be affiliated with compromised left ventricular relaxation.

Effect of increased cardiac output on hepatic and intestinal microcirculatory blood flow, oxygenation, and metabolism in hyperdynamic murine septic shock.

OBJECTIVE: Septic shock-associated organ dysfunction is attributed to derangements of microcirculatory perfusion and/or impaired cellular oxygen utilization. The hepatosplanchnic organs are regarded to play a pivotal role in the pathophysiology of sepsis-related organ failure. In a murine model of septic shock, we tested the hypothesis whether achieving normotensive, hyperdynamic hemodynamics characterized by a sustained increase in cardiac output would allow maintenance of regional microvascular perfusion and oxygenation and, thus, hepatic metabolic capacity. DESIGN: Prospective, controlled, randomized animal study. SETTING: University animal research laboratory. SUBJECTS: Male C57Bl/6 mice. INTERVENTIONS: Fifteen hours after sham operation (n = 11) or cecal ligation and puncture (CLP) (n = 9), mice were anesthetized, mechanically ventilated, and instrumented (central venous and left ventricular pressure-conductance catheter, portal vein and superior mesenteric artery ultrasound flow probes). Animals received continuous intravenous hydroxyethylstarch and norepinephrine to achieve normotensive and hyperdynamic hemodynamics, and glucose was infused to maintain normoglycemia. MEASUREMENTS AND MAIN RESULTS: Measurements were recorded 18, 21, and 24 hrs post-CLP. In CLP mice, titration of hemodynamic targets were affiliated superior mesenteric artery and portal vein flow. Using a combined laser-Doppler flowmetry and remission spectrophotometry probe, we found well-maintained gut and liver capillary perfusion as well as intestinal microcirculatory hemoglobin oxygen saturation, whereas hepatic microcirculatory hemoglobin oxygen saturation was even increased. At 24 hrs post-CLP, the rate of de novo gluconeogenesis as derived from hepatic C-glucose isotope enrichment after continuous intravenous 1,2,3,4,5,6-C6-glucose infusion (condensation biosynthesis modeling after gas chromatography-mass spectrometry isotope measurements) was similar in the two experimental groups. CONCLUSIONS: During murine septic shock achieving normotensive hyperdynamic hemodynamics with fluid resuscitation and norepinephrine, exogenous glucose requirements together with the lack of norepinephrine-induced increase in the rate of gluconeogenesis mirror impaired metabolic capacity of the liver despite well-maintained hepatosplanchnic microvascular perfusion and oxygenation.

Determination of fractional synthesis rates of mouse hepatic proteins via metabolic 13C-labeling, MALDI-TOF MS and analysis of relative isotopologue abundances using average masses.

Proteins of a liver extract taken from a metabolically (13)C-labeled mouse were separated by 2D-PAGE and identified after tryptic digestion by MALDI-TOF MS peptide mass fingerprinting. (13)C-Labeling of proteins was achieved by an infusion of U-(13)C-glucose, which is metabolized to labeled nonessential amino acids. The labeling was analyzed using the relative isotopologue abundances of the measured isotope pattern of tryptic peptides and quantified by their increase in the average molecular mass (DeltaAVM). Fractional synthesis rates (FSR) of proteins were determined from corresponding peptides using measured DeltaAVM values as well as DeltaAVM values deduced from tRNA-precursor amino acid labeling, which in turn was derived from proteins showing high (13)C enrichments. The 8-h FSR values of 43 proteins were determined to range from 0 +/- 0.6 to 95 +/- 1%/8 h, with typical errors given as SEM values, which depend on the number of peptides of a specific protein usable for calculation. The method demonstrates that FSR values as an indicator for protein turnover in the liver proteome can be estimated within narrow error margins, providing baseline values from which treatment-dependent deviations could be detected with high statistical certainty.