Does prior transfusion worsen outcomes from infection in surgical patients?

The role of patient's profile and allogeneic blood transfusion in development of post-cardiac surgery infections: a retrospective study

OBJECTIVES

We aimed to investigate the association of patient characteristics and allogeneic blood transfusion products in development of post-cardiac surgery nosocomial infections.

METHODS

This retrospective study was conducted in 7888 patients undergoing cardiac surgery with median sternotomy and cardiopulmonary bypass. Multivariable logistic regression analysis was used for independent effect of variables on infections.

RESULTS

A total of 970 (12.3%) patients developed one or several types of postoperative infections. Urinary (n = 351, 4.4%) and pulmonary tract infections (n = 478, 6.1%) occurred more frequently than sternal wound infections (superficial: n = 102, 1.3%, deep: n = 72, 0.9%) and donor site infections (n = 61, 0.8%). Interventions, including valve replacement (P = 0.002) and coronary artery bypass grafting combined with valve replacement (P = 0.012), were associated with increased risk of several types of postoperative infections. Patients' profiles changed substantially over the years; morbid obesity (P = 0.019), smoking (P = 0.001) and diabetes mellitus (P = 0.001) occur more frequently nowadays. Furthermore, surgical site infections showed to be related to morbid obesity (P < 0.001) and higher risk stratification (P = 0.031). Smoking (P < 0.001) and chronic obstructive pulmonary disease (P < 0.001) were related to pulmonary tract infections. In addition, diabetic patients developed more sepsis (P = 0.003) and advanced age was associated with development of urinary tract infections (P < 0.001). Even after correcting for other factors, blood transfusion was associated with all types of postoperative infection (P < 0.001). This effect remained present in both leucocyte-depleted and non-leucocyte-depleted transfusion.

CONCLUSIONS

Our data showed that post-cardiac surgery infections occur more frequently in patients with predetermined risk factors. The amount of blood transfusions was integrally related to every type of postoperative infection.

Allogeneic versus autologous blood transfusion and survival after radical prostatectomy

BACKGROUND

Potential adverse effects of blood transfusion (BT) remain controversial, especially for clinical outcomes after curative cancer surgery. Some postulate that immune modulation after allogeneic BT predisposes to recurrence and death, but autologous superiority is not established. This study assessed whether BT is associated with long-term prostate cancer recurrence and survival with a large single-institutional radical prostatectomy (RP) database.

STUDY DESIGN AND METHODS

Between 1994 and 2012, a total of 11,680 patients had RP with available outcome and transfusion data. A total of 7443 (64%) had complete covariate data. Clinical variables associated with biochemical recurrence-free survival (BRFS), cancer-specific survival (CSS), and overall survival (OS) were identified with Cox proportional hazards models for three groups: no BT (reference, 27.7%, n = 2061), autologous BT only (68.8%, n = 5124), and any allogeneic BT (with or without autologous, 3.5%, n = 258).

RESULTS

Median (range) follow-up was 6 (1-18) years. Kaplan-Meier analysis showed significantly decreased OS (but not BRFS or PCSS) in the allogeneic group versus autologous and no BT groups (p = 0.006). With univariate analysis, any allogeneic BT had a hazard ratio (HR) of 2.29 (range, 1.52-3.46; p < 0.0001) for OS, whereas autologous BT was not significant (HR, 1.04 [range, 0.82-1.32], p = 0.752). In multivariable models, neither autologous nor allogeneic BT was independently associated with BRFS, CSS, or OS, and a dose response was not observed for allogeneic units and BRFS.

CONCLUSION

Although allogeneic but not autologous BT was associated with decreased long-term OS, after adjustment for confounding clinical variables, BT was not independently associated with OS, BRFS, or CSS regardless of transfusion type. Notably, no association was observed between allogeneic BT and cancer recurrence. Observed differences in OS may reflect confounding.

Candida isolation in patients hospitalized on a surgical ward: significance and mortality-related factors

BACKGROUND

Infections caused by Candida are an emerging pathology on surgical wards. The aim of the present study was to evaluate the incidence, characteristics, and predictive factors of mortality in patients colonized and/or infected by Candida spp. in this setting.

METHODS

A consecutive series of 105 patients hospitalized on a general surgery ward between 2000 and 2004 were included, and 118 positive cultures for Candida were identified. The variables age, sex, previous medical history, current disease, anemia, ICU stay, type and localization of the microorganism, need for parenteral nutrition, and transfusions were recorded. The primary outcome was in-hospital mortality. A univariate analysis was performed to determine which of these variables were associated with mortality. With a logistic regression model, independent prognostic factors of mortality were determined.

RESULTS

The prevalence of patients colonized and/or infected by Candida on our surgical ward was 0.98% (CI 95%: 0.79-1.17), and the incidence was 49 cases per 1,000 patient-years. Of the 105 patients in this series, 56 were men (53%) and 49 women (47%); the mean age was 63.8 years (SD +/- 15.7). Twelve patients (11.4%) had candidemia. Crude mortality was 23% (24 patients), whereas the mortality attributable to candidemia was 25% (3/12 cases). Anemia (p = 0.001); transfusions (p = 0.003), and an ICU stay (p = 0.002) were associated with mortality. Candidemia was associated with neoplasms (p = 0.02) and the infection caused by Candida parapsilosis (p = 0.04). The only independent factor related to mortality was the anemia (p = 0.028; Odds Ratio: 6.43; 95% CI: 1.23-33.73).

CONCLUSIONS

Colonization and/or infection by Candida spp. in non-ICU hospitalized surgical patients implies a relative high mortality. Anemia is an independent factor for mortality.

Blood product transfusion and ventilator-associated pneumonia in trauma patients

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in trauma patients, with a high mortality rate. Blood transfusion has been identified as an independent risk factor for VAP in critically ill patients. Prior studies in trauma are limited by retrospective design, lack of multivariable analyses, and scant data on the timing of transfusion. We examined critically the relation between blood product transfusion and VAP in trauma patients.

METHODS

Prospective observational cohort study of 766 trauma patients admitted to the intensive care unit (ICU), who received mechanical ventilation (MV) for >or= 48 h, and who did not have pneumonia on admission. Late-onset VAP was defined as that occurring >or= 72 h after MV. Only transfusions of red blood cell (RBC) concentrate, fresh-frozen plasma (FFP), or platelets before the onset of VAP were considered. Logistic regression analyses controlled for all variables related significantly to VAP by univariate analysis (sex, Injury Severity Score, and ventilator days and ICU length of stay prior to VAP).

RESULTS

A significantly greater proportion of male patients developed VAP. Patients with VAP had a longer duration of MV: The mean number ventilator days prior to VAP was 11.1 +/- 8.0. Transfusion of blood products was an independent risk factor for VAP, and the risk increased with more units transfused. All blood products were associated with a higher risk of VAP (RBC: odds ratio [OR] 4.41; 95% confidence interval [CI] 1.00, 19.54; p = 0.05; FFP: OR 3.34; 95% CI 1.18, 9.43; p = 0.023; platelets: OR 4.19; 95% CI 1.37, 12.83; p = 0.012).

CONCLUSION

Blood product transfusion is an independent risk factor for VAP in trauma, and the odds ratio is significantly higher (3.34-4.41) than in published studies of other types of ICU patients (1.89). To reduce the incidence of VAP, all efforts to reduce the transfusion of blood products to trauma patients should be implemented.

Cost of Gram-negative resistance*

OBJECTIVE

It is unclear that infections with Gram-negative rods resistant to at least one major class of antibiotics (rGNR) have a greater effect on patient morbidity than infections caused by sensitive strains (sGNR). We wished to test the hypothesis that rGNR infections are associated with higher resource utilization.

DESIGN

Retrospective observational cohort study of prospectively collected data.

SETTING

University hospital surgical intensive care unit and ward.

PATIENTS

Surgical patients with at least one GNR infection.

MEASUREMENTS

We compared admissions treated for rGNR infection with those with sGNR infections. Primary outcomes were total hospital costs and hospital length of stay. Other outcomes included antibiotic treatment cost, in-hospital death, and intensive care unit length of stay. After univariate analysis comparing outcomes after rGNR infection with those after sGNR infection, multivariate linear regression models for hospital cost and length of stay were created to account for potential confounders.

MAIN RESULTS

Cost data were available for 604 surgical admissions treated for at least one GNR infection (Centers for Disease Control and Prevention criteria), 137 (23%) of which were rGNR infections. Admissions with rGNR infections were associated with a higher severity of illness at the time of infection (Acute Physiology and Chronic Health Evaluation II score, 17.6 +/- 0.6 vs. 13.9 +/- 0.3), had higher median hospital costs ($80,500 vs. $29,604, p < .0001) and median antibiotic costs ($2,607 vs. $758, p < .0001), and had longer median hospital length of stay (29 vs. 13 days, p < .0001) and median intensive care unit length of stay (13 days vs. 1 day, p < .0001). Infection with rGNR within the first 7 days of admission was independently predictive of increased hospital cost (incremental increase in median hospital cost estimated at $11,075; 95% confidence interval, $3,282-$20,099).

CONCLUSIONS

Early infection with rGNR is associated with a high economic burden, which is in part related to increased antibiotic utilization compared with infection with sensitive organisms. Efforts to control overuse of antibiotics should be pursued.

Massive blood transfusion and outcome in 1062 polytrauma patients: a prospective study based on the Trauma Registry of the German Trauma Society

BACKGROUND AND OBJECTIVES

About 15% of polytrauma patients receive massive blood transfusion (MBT) defined as > or = 10 units of packed red blood cells (PRBC). In general, the prognosis of trauma patients receiving MBT is considered to be poor. The purpose of this study was to investigate the impact of MBT on the outcome of polytrauma patients.

MATERIALS AND METHODS

Records of 10 997 patients in the Trauma Registry of the German Trauma Society were analysed. Transfusion data were available from 8182 severe trauma patients with a mean injury severity score of 24.5 and, of these 8182 patients, 1062 received > or = 10 units of PRBC. First, a logistic regression model for the predictors of mortality was performed. Second, incidences of organ failure and sepsis as well as survival rates were analysed.

RESULTS

The highest risk for mortality was age over 55 years (odds ratios [OR] 4.7; confidence intervals [CI 95%], 3.5-6.5) followed by Glasgow Coma Scale < or = 8 (OR 4.6; 3.4-6.1), MBT > or = 20 units of PRBC (OR 3.3; 2.1-5.4), thromboplastin time < 50% (OR 3.2; 2.2-4.4) and injury severity score > or = 24 (OR 2.9; 2.1-4.1). Transfusion of 10-19 PRBC was identified as the variable with the lowest risk for mortality (OR 1.5; 1.0-2.3). Risk of organ failure, sepsis and death correlated with increasing transfusion amount. For the MBT patients, the survival rate was 56.9% (CI 95%, 53.9-59.9%) compared to 85.2% (84.4-86.0%) of non-MBT patients (P < 0.001). In the MBT group with > 30 PRBC (mean 40.6 PRBC) 39.6% survived (31.7-47.5%).

CONCLUSION

Massive blood transfusion is one main prognostic factor for mortality in trauma. Although MBT is generally considered to be critical, every second trauma patient with MBT survived. A cut-off value for the number of PRBC could not be determined. Extended transfusion management even with high amounts of PRBC seems to be justified.

A review of the application of propensity score methods yielded increasing use, advantages in specific settings, but not substantially different estimates compared with conventional multivariable methods

OBJECTIVE

Propensity score (PS) analyses attempt to control for confounding in nonexperimental studies by adjusting for the likelihood that a given patient is exposed. Such analyses have been proposed to address confounding by indication, but there is little empirical evidence that they achieve better control than conventional multivariate outcome modeling.

STUDY DESIGN AND METHODS

Using PubMed and Science Citation Index, we assessed the use of propensity scores over time and critically evaluated studies published through 2003.

RESULTS

Use of propensity scores increased from a total of 8 reports before 1998 to 71 in 2003. Most of the 177 published studies abstracted assessed medications (N=60) or surgical interventions (N=51), mainly in cardiology and cardiac surgery (N=90). Whether PS methods or conventional outcome models were used to control for confounding had little effect on results in those studies in which such comparison was possible. Only 9 of 69 studies (13%) had an effect estimate that differed by more than 20% from that obtained with a conventional outcome model in all PS analyses presented.

CONCLUSIONS

Publication of results based on propensity score methods has increased dramatically, but there is little evidence that these methods yield substantially different estimates compared with conventional multivariable methods.

Comparison of fungal and nonfungal infections in a broad-based surgical patient population

BACKGROUND

Our aim was to compare fungal and nonfungal infections among a diverse surgical patient population.

METHODS

Data on all hospital-acquired infectious episodes among surgical intensive care unit and ward patients were collected prospectively over six years at a single university hospital. The relationships between fungal and nonfungal infection and over 100 variables were examined using univariate and multiple logistic regression analysis.

RESULTS

During the study period, 3,980 infectious episodes were identified; 554 were associated with fungal infection. Multiple logistic regression analysis demonstrated that markers of severity of acute illness (higher APACHE II scores and white blood cell counts, greater transfusion of cellular blood products, mechanical ventilator dependency, and prior infection) predicted fungal infection, whereas markers of chronic illness (comorbidities) did not independently predict either fungal or nonfungal infection. Patients with fungal infection were treated with more antibiotics for longer periods of time, had prolonged lengths of stay, and more often died compared with nonfungal infection patients. A separate multiple logistic regression analysis demonstrated that both fungal infection and the number of fungal sites of infection independently predicted mortality. Of all fungal isolates, only Candida albicans and Aspergillus spp. independently predicted mortality.

CONCLUSIONS

Fungal infections differ significantly in character and outcomes from nonfungal infections among surgical patients.