Independent determinants of early death in critically ill surgical patients

Female sex protects from organ failure and sepsis after major trauma haemorrhage

INTRODUCTION

Biological sex is considered a risk factor for adverse outcome after major trauma. We hypothesized that female sex is protective against organ failure, sepsis and mortality in patients with traumatic haemorrhage.

PATIENTS AND METHODS

We selected patients from TraumaRegister DGU(®) (TR-DGU) with primary admission for blunt trauma with an injury severity score ≥ 16 and an ICU stay ≥ 3 days that presented with relevant bleeding in the years 2007-2012. Relevant bleeding was defined as Abbreviated Injury Scale (AIS) ≥ 3 with an estimated blood loss exceeding 20%, any femoral shaft fracture, any pelvic clamp as surrogate for unstable pelvic fracture or the presence of at least one criteria of haemorrhagic shock: shock index of 0.8-1.4; base excess of -2.0 to -10.0 mmol/L; body temperature ≤ 34°C; transfusion of ≥ 4 units of packed red blood cells; application of recombinant activated factor VII; any embolization during trauma room phase and pre-hospital resuscitation volume ≥ 3000 ml or any catecholamine use during pre-hospital care in the absence of cardiopulmonary resuscitation. A total of 7560 males and 2774 females were selected and analyzed for sex differences.

RESULTS

Higher rates of multiple organ failure (24.4 vs. 21.3%, Odds ratio [OR] 1.19 (95% confidence interval [95%CI] 1.07-1.33), p=0.001*) and sepsis (16.5 vs. 11.3%, OR 1.55 (95%CI 1.35-1.77), p<0.001*) were observed in males. Organ function of lung, cardio-circulatory system, liver and kidney were better in females, however, there was no difference in mortality. Stratification by age group revealed that in particular age-group 16-44 years was related to improved organ function which may indicate effects of sex hormones in females at reproductive age. Increased rates of sepsis in males were observed throughout virtually all age groups starting at 16 years of age, except in age group 54-64 years. This may suggest suppressive effect of testosterone on immune function.

CONCLUSIONS

Our study supports the hypothesis that female sex is associated with improved organ function following traumatic injury and haemorrhagic shock, in particular in age groups that are at reproductive age. However, further studies are warranted before sex steroids can be deployed as therapeutic intervention in critically ill trauma patients.

Hypothermia for prediction of death in severely injured blunt trauma patients

Hypothermia is considered an independent predictor of death after trauma. The aim of this study was to assess these premises based on data from the TraumaRegistry DGU® (TR-DGU) using its outcome predication tool, the Revised Injury Severity Classification (RISC) score, in comparison with three previously published regression models by Shafi, Martin, and Wang. We hypothesized that body temperature on admission would improve accuracy of the RISC score. Data of 5,197 patients with documented body temperature on admission (T) and complete data for RISC score prognosis were selected from TR-DGU. Hypothermia was defined as T of 35°C or less. Patients were divided into hypothermia and normothermia group. Differences were assessed using Mann-Whitney U and chi-squared tests. Statistical significance was accepted at P < 0.01(*). Moreover, we performed multivariate logistic regression analyses using TR-DGU data on the four models (including RISC) with hospital mortality as dependant variable. Results are given as mean or odds ratio (OR) with 95% confidence intervals (95% CIs). Hypothermic patients were more severely injured (Injury Severity Score, 35.0 vs. 29.2 points*) and had higher rates of shock (38.3 vs. 16.8%*), organ failure (71.8 vs. 46%*), and sepsis (17.5 vs. 10.6%*). Survival was worse (29.2 vs. 13.7%*). Comparison of the above models revealed hypothermia as an independent risk factor (Martin: OR, 1.43 [95% CI, 2.21-1.42*]; and Wang: OR, 1.77 [95% CI, 2.21-1.42*]) only, although it would drop out from the model (RISC: OR, 1.12 [95% CI, 1.41-0.89; P = 0.33] and Shafi: OR, 1,.21 [95% CI, 1.60-0.92; P = 0.17]) as long as parameters to indicate hemorrhage and/or coagulopathy were included in sufficient number, a finding confirmed by a subsequent sensitivity analysis. We conclude that hypothermia is a result of injury severity and therefore unlikely to be an independent predictor of mortality. Our data suggest that hypothermia belongs closely to the hemorrhage/coagulopathy group of predictors.

Short-term prognosis of critically ill surgical patients: the impact of duration of invasive organ support therapies

PURPOSE

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).

METHODS

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.

MEASUREMENTS AND MAIN RESULTS

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.

CONCLUSION

Prolonged duration of invasive ventilation but not of renal replacement therapy is inversely related to short-term survival.

Long-term survival after surgical critical illness: the impact of prolonged preceding organ support therapy

OBJECTIVE

To identify the prognostic importance of preceding invasive ventilation, renal replacement therapy, and catecholamine therapy for long-term survivors after surgical critical illness.

SUMMARY BACKGROUND DATA

Nothing is known about the effect of preceding intensive care unit (ICU)-related therapies on long-term outcome.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Prognostic factors in critically ill patients suffering from secondary peritonitis: a retrospective, observational, survival time analysis

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Perioperative fluid retention and clinical outcome in elective, high-risk colorectal surgery

BACKGROUNDS AND AIMS

There is some controversy regarding concepts currently propagated for an optimal perioperative fluid management in colorectal surgery. We wanted to analyze the association of net intraoperative and postoperative fluid balances with postoperative morbidity and length of stay.

MATERIALS AND METHODS

We performed a retrospective analysis of data collected prospectively from March 1993 through February 2005. A subgroup from 4,658 patients was studied who had undergone major elective colorectal surgery during that time. This subgroup included 198 patients with a particularly high preoperative risk profile requiring immediate postoperative intensive care unit (ICU) admission. Fluid therapy was guided by established clinical end points. Results were adjusted for various confounding variables (extent of the operative trauma, individual response to the injury, type of analgesia, underlying disease, treatment era).

RESULTS/FINDINGS

After adjustment for relevant covariates, the magnitude of fluid balance was unimportant for morbidity and postoperative hospital length of stay. A high Apache II score after ICU admission, an increased perioperative blood loss, and palliative surgical procedures were associated with a significantly higher complication rate, whereas use of epidural analgesia improved morbidity and shortened hospital stay.

INTERPRETATION/CONCLUSION

If guided by established standards, even large perioperative fluid retentions do not appear to be associated with a worse outcome after extended colorectal surgery. Epidural analgesia may provide a significant benefit in those high-risk patients.