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ABSTRACT: The Nutritional Risk Screening-2002 (NRS-2000) is currently recommended by the European Society of Parenteral and Enteral Nutrition as a screening tool in hospitalized patients. However, for preoperative risk prediction, the usefulness of this tool is uncertain and may depend on the type of surgical disease. The present study investigated the relative prognostic importance of the NRS-2002 and of established medical and surgical predictors for postoperative complications in patients scheduled for non-abdominal procedures.
In this prospective observational study, we enrolled 581 patients scheduled for elective non-abdominal surgery. Data were collected on nutritional variables (body mass index, weight loss, and food intake), age, gender, type of surgery, extent of surgery, underlying disease, American Society of Anesthesiologists class, and comorbidity. We also evaluated a modification of the NRS-2002 (ordinal graduation according to <2 or ≥2 points) and the importance of individual parameter values. Relative complication rates were calculated with generalized linear models and cumulative proportional odds models.
Forty-four patients (7.6%) sustained at least one postoperative complication. The frequency of this event increased significantly with a higher NRS-2002 score. However, the model that performed the best (sensitivity 81.8%, specificity 78.6%) included the modified NRS-2002 graduation (<2 or ≥2 points) and other factors such as American Society of Anesthesiologists class, the duration of the procedure, and the need for red blood cell transfusion.
In surgical patients with non-abdominal diseases, a modified NRS-2002 classification may be required to preoperatively identify patients at a high nutritional risk. The NRS-2002 alone is insufficient to precisely predict complications.
Nutrition 02/2013; 29(2):399-404. · 3.03 Impact Factor
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ABSTRACT: Duration of surgical therapy and the number of surgical revisions performed to control the focus may be important prognostic variables. Association of such time-dependent therapies with survival, however, has not yet been studied.
We analyzed survival times of adult patients (n = 283) who were suffering from secondary peritonitis and associated organ failure. Cox-type additive hazard regression models were used to analyze associations of surgical variables with survival time.
Seventy-two patients (25.4%) survived the period of excess mortality after intensive care unit admission. A total of 79.5% of the 283 patients required one or more surgical revisions. Besides the underlying disease and disease severity at intensive care unit admission, there was a nonlinear smoothed association between a poorer outcome and the duration of surgical therapy, and the number of surgical revisions. For the latter, hazard ratios increased sharply between 1 and 5 revisions, and remained largely constant later on.
In critically ill patients with peritonitis, a long therapy and the necessity for a high number of reoperations is related inversely to acute survival.
American journal of surgery 01/2012; 204(1):28-36. · 2.36 Impact Factor
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ABSTRACT: We wanted to identify the importance of the duration of invasive ventilation and of renal replacement therapy for short-term prognosis of surgical patients treated in an intensive care unit (ICU).
We analyzed adult patients (n = 1462) who had an ICU length of stay of more than 4 days and who were followed up until the end of the short-term phase after ICU admission. Duration of different invasive therapies was evaluated by constructing specific vectors that tested effects of time-dependent variables on outcome after a lag time of 7 days.
Eight hundred eight patients (56.6%) were still alive at the end of the short-term phase. During the short-term phase, 85.3% of the 1462 patients required invasive ventilation, and 16.1%, a continuous renal replacement therapy. Besides the underlying disease and disease severity at ICU admission, the need for invasive ventilation or renal replacement therapy was associated with poorer outcome. Duration of invasive ventilation shortened survival if treatment lasted for more than 11 days (nonlinear association). In contrast, duration of renal replacement therapy was unimportant for short-term prognosis.
Prolonged duration of invasive ventilation but not of renal replacement therapy is inversely related to short-term survival.
Journal of critical care 07/2011; 27(1):73-82. · 2.13 Impact Factor
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ABSTRACT: To identify the prognostic importance of preceding invasive ventilation, renal replacement therapy, and catecholamine therapy for long-term survivors after surgical critical illness.
Nothing is known about the effect of preceding intensive care unit (ICU)-related therapies on long-term outcome.
We performed a retrospective analysis of prospectively collected data of an ICU patient cohort linked to a local database. Adult patients (n = 1462) admitted to a 12-bed ICU between 1993 and 2005, who had an ICU length of stay of more than 4 days, were followed up until the end of the second year after ICU admission. Hazard function was explored by Weibull modeling and likelihood ratio tests. Cox-type structured hazard regression models were used to analyze linear, nonlinear, or time-varying associations of therapeutic variables with 2-year survival time of a patient subgroup, which had survived the period of high hazard.
Hazard rate declined exponentially up to day 195 after ICU admission, and became constant thereafter. A total of 808 patients reached this stable stage of their disease forming the study population. Of these patients, 648 (80.2%) were still alive at the end of the second year after ICU admission. Underlying diseases were major determinants for long-term outcome. Long-term mortality was significantly associated with the acute extent of physiological derangement during ICU stay (maximum Apache II score), but was independent from the duration of preceding invasive organ support.
In surgical patients with a prolonged ICU length of stay, an exorbitant mortality exists for about half a year after ICU admission. Later on, life expectancy of surviving patients is largely determined by the underlying disease and, to a minor degree, by the acute extent of homeostatic disturbance during ICU stay. The duration of preceding invasive therapies does not limit long-term survival.
Annals of surgery 06/2010; 251(6):1145-53. · 7.90 Impact Factor
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ABSTRACT: Recent controlled studies that evaluated the efficacy of an adjuvant antithrombin (AT) III therapy in severe sepsis used a uniform AT-III dose and duration of therapy and did not adjust to the actual AT-III deficit. It was the aim of the present study to explore if surgical patients with severe sepsis might have a treatment benefit from an activity-guided AT-III therapy. We performed a retrospective cohort analysis using an intensive care unit (ICU) database. To examine the effect of AT-III on outcome and on red cell transfusion rate, multivariate generalized additive models (GAMs), Cox-type additive hazard regression models, and propensity score adjustments were used. Five hundred forty-five postoperative surgical patients requiring ICU therapy because of severe sepsis were analyzed. Antithrombin III was given to those patients believed to be at a high risk of dying. Antithrombin III therapy was guided by the individual AT-III activity and aimed at the maintenance of an activity of at least 100%. Antithrombin III supplementation was discontinued after the plasma AT-III activity had been persistently normal without simultaneous AT-III infusion. We found that patients receiving additional AT-III (n = 230) were sicker than those on standard therapy (n = 315; admission Acute physiology and chronic health evaluation II score, 19.8 +/- 7.3 vs. 17.9 +/- 7.1 [mean +/- SD]; P < 0.005). Correspondingly, 28-day mortality was higher in patients who had an additional AT-III therapy than in those on standard therapy (46.3% vs. 36.9%; P < 0.03), as was the number of red cell units transfused during ICU stay (21.5 +/- 26.7 vs. 9.3 +/- 12.1; P < 0.001). At multivariate analysis, there was no significant effect of AT-III therapy on 28-day mortality (GAM: odds ratio, 1.012; 95% confidence interval [CI], 0.651 - 1.573; P = 0.957) and 90-day survival time (Cox-type additive hazard regression: hazard ratio, 1.034; 95% CI, 0.779 - 1.387; P = 0.794). However, AT-III therapy was associated with a significantly higher frequency of red cell unit transfusion (GAM/zero-inflated Poisson: estimate, 1.26; 95% CI, 1.15 - 139; P < 0.001). Our results suggest that there seems to be no relevant effect of an activity-guided AT-III therapy on the prognosis of surgical patients with severe sepsis. However, transfusion frequency rises by AT-III therapy.
Shock (Augusta, Ga.) 12/2008; 30(6):634-41. · 2.87 Impact Factor
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ABSTRACT: Acute mortality of unselected critically ill patients has improved during the last 15 years. Whether these benefits also affect survival of critically ill patients with secondary peritonitis is unclear as is the relevance of specific prognostic factors, such as source control.
We performed a retrospective analysis of data collected prospectively from March 1993 to February 2005. A cohort of 319 consecutive postoperative patients with secondary peritonitis requiring intensive care was evaluated. End points for outcome analysis were derived from daily changes of hazard rate.
Four-month survival rate after intensive care unit (ICU) admission was 31.7%. For patients who have survived for more than 4 months, the 1-year survival was 82.7%. After adjustment for relevant covariates, a high disease severity at ICU admission and during ICU stay, specific comorbidities (extended malignancies, liver cirrhosis) and sources of infection (distal esophagus, stomach), and an inadequate initial antibiotic therapy were associated with worse 4-month prognosis. Inability to obtain source control was the most important determinant of mortality, and treatment after 2002 was combined with improved prognosis.
Four-month prognosis of critically ill, surgical patients with secondary peritonitis is poor and mostly determined by the ability to obtain source control. Outcome has improved since 2002, and after successful surgical and intensive care therapy long-term survival seems to be good.
World Journal of Surgery 12/2008; 33(1):34-43. · 2.36 Impact Factor
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ABSTRACT: Abnormalities in cardiocirculatory, respiratory, or coagulatory parameters are frequent after major surgery, but so far, no study has investigated their predictive value for early intensive care unit (ICU) mortality. We aimed to describe and quantify the relation between these parameters that are routinely determined on ICU admission and early death after complex surgery. Individual patient data were available from a local ICU database. We performed a retrospective observational cohort study using prospectively collected data from March 1, 1993, through February 28, 2005. A cohort of 4,214 cases who were admitted to the ICU immediately after operation was analyzed. We studied age, sex, number of red blood cell units transfused on admission day, and admission values for heart rate, systolic blood pressure, hemoglobin concentration, partial thromboplastin time, prothrombin time, respiratory function (Pao2/Fio2 ratio), and body temperature for their association with 4-day mortality. Effects were adjusted for the underlying disease and for disease severity during the first 24 h after admission. We used generalized additive models to fit continuous variables individually before combining them into the final generalized model. We found an independent linear association between the number of transfused red blood cell units, partial thromboplastin time, and body temperature with acute outcome. A smoothed model described the independent interaction between admission blood pressure and early death. Only values of less than 80 mmHg were associated with an increased risk of 4-day mortality. According to these results, bleeding complications after ICU admission should be treated aggressively to prevent early death of the patient. However, normotensive conditions do not seem to be required to prevent early mortality. Whether rapid rewarming may improve outcome needs further rigorous study.
Shock 02/2008; 30(1):11-6. · 2.85 Impact Factor
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ABSTRACT: Since 1999 randomized controlled trials have shown that new therapeutic strategies, such as strict glycemic control, increased use of noninvasive ventilation and of lung-protective ventilation, and early goal-oriented shock therapy, may reduce mortality in selected groups of critically ill patients. Whether these benefits can be translated to a surgical clinical setting is unclear. We wanted to evaluate longitudinally the successive routine implementation of new therapeutic measures and its effect on postsurgical patients admitted to the intensive care unit.
We performed a retrospective analysis on data collected prospectively from March 1, 1993 through February 28, 2005.
A cohort of 1,802 consecutive cases requiring intensive care therapy for more than 4 days was analyzed. A significant decrease in mortality was observed in the last years of the study. With adjustment for relevant covariates, treatment after the implementation of new therapeutic strategies was identified as an independent factor linked with a reduced risk of death (odds ratio [OR] .518; 95% confidence interval [CI] .337-.796), whereas older age (OR 1.030; 95% CI 1.015-1.045), a high severity score on admission (OR 1.155; 95% CI 1.113-1.198) or during intensive care unit stay (OR 1.187; 95% CI 1.145-1.231), a high number of failing organs (OR 1.918; 95% CI 1.635-2.250), and peritonitis (OR 3.277; 95% CI 2.046-5.246) were independently associated with death.
Implementing of a variety of new therapeutic measures into routine care of critically ill surgical patients was associated with improved survival after 2001.
American journal of surgery 11/2007; 194(4):535-41. · 2.36 Impact Factor
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ABSTRACT: In contrast to randomized studies, previous cohort studies identified red cell transfusion as an independent predictor of mortality in critically ill patients. However, these cohort studies did not adjust for disease severity during intensive care unit (ICU) stay. We performed a retrospective, observational cohort study using prospectively collected data from March 1, 1993, through February 28, 2005. A cohort of 3037 consecutive surgical cases requiring intensive care therapy for more than one day was analyzed. We used two different sets of potentially confounding covariables (admission variables only or in combination with variables reflecting number and extent of organ dysfunction during ICU stay). We found that the total number of red cell units which a case had received during ICU stay, and the maximum number of units given on a single day, were independently associated with an increase in ICU mortality when only admission variables were considered for the analysis. After controlling for the additional effect of variables reflecting organ dysfunction during ICU stay, we found that red cell transfusion was no longer an independent risk factor for death. However, there was a significant effect of red cell transfusion on ICU LOS in survivors irrespective of the covariable sets used. We conclude that red cell transfusion during ICU stay may be only a surrogate marker for disease severity and is not causally related to ICU mortality. Relevant side effects of red cell transfusion are presumably small and may be only recognizable in surviving cases.
Shock 09/2007; 28(2):165-71. · 2.85 Impact Factor
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ABSTRACT: Various cohort studies have shown that acute (short-term) mortality rates in unselected critically ill patients may have improved during the past 15 years. Whether these benefits also affect acute and long-term prognosis in chronically critically ill patients is unclear, as are determinants relevant to prognosis.
We conducted a retrospective analysis of data collected from March 1993 to February 2005. A cohort of 390 consecutive surgical patients requiring intensive care therapy for more than 28 days was analyzed.
The intensive care unit (ICU) survival rate was 53.6%. Survival rates at one, three and five years were 61.8%, 44.7% and 37.0% among ICU survivors. After adjustment for relevant covariates, acute and long-term survival rates did not differ significantly between 1993 to 1999 and 1999 to 2005 intervals. Acute prognosis was determined by disease severity during ICU stay and by primary diagnosis. However, only the latter was independently associated with long-term prognosis. Advanced age was an independent prognostic determinant of poor short-term and long-term survival.
Acute and long-term prognosis in chronically critically ill surgical patients has remained unchanged throughout the past 12 years. After successful surgical intervention and intensive care, long-term outcome is reasonably good and is mainly determined by age and underlying disease.
Critical care (London, England) 02/2007; 11(3):R55. · 4.61 Impact Factor
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ABSTRACT: Investigating habitat selection of animals aims at the detection of preferred and avoided habitat types as well as at the identification of covariates influencing the choice of certain habitat types. The final goal of such analyses is an improvement of the conservation of animals. Usually, habitat selection by larger animals is assessed by radio-tracking or visual observation studies, where the chosen habitat is determined for a number of animals at a set of time points. Hence the resulting data often have the following structure: A categorical variable indicating the habitat type selected by an animal at a specific time point is repeatedly observed and shall be explained by covariates. These may either describe properties of the habitat types currently available and / or properties of the animal. In this paper, we present a general approach for the analysis of such data in a categorical regression setup. The proposed model generalises and improves upon several of the approaches previously discussed in the literature and in particular allows to account for changing habitat availability due to the movement of animals within the observation area. It incorporates both habitat- and animal-specific covariates, and includes individual-specific random effects in order to account for correlations introduced by the repeated measurements on single animals. The methodology is implemented in a freely available software package. We demonstrate the general applicability and the capabilities of the proposed approach in two case studies: The analysis of a songbird in South-America and a study on brown bears in Central Europe.
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ABSTRACT: In recent years, flexible hazard regression models based on penalised splines have been developed that allow us to extend the classical Cox-model via the inclusion of time-varying and nonparametric effects. Despite their immediate appeal in terms of flexibility, these models introduce additional difficulties when a subset of covariates and the corresponding modelling alternatives have to be chosen. We present an analysis of data from a specific patient population with 90-day survival as the response variable. The aim is to determine a sensible prognostic model where some variables have to be included due to subject-matter knowledge while other variables are subject to model selection. Motivated by this application, we propose a twostage stepwise model building strategy to choose both the relevant covariates and the corresponding modelling alternatives within the choice set of possible covariates simultaneously. For categorical covariates, competing modelling approaches are linear effects and time-varying effects, whereas nonparametric modelling provides a further alternative in case of continuous covariates. In our data analysis, we identified a prognostic model containing both smooth and time-varying effects.
