Transfusion practice and blood stream infections in critically ill patients

Risk factors for bloodstream infection (BSI) in patients with severe acute respiratory distress syndrome (ARDS) supported by veno-venous extracorporeal membrane oxygenation (VV-ECMO)

Background

There were relatively few studies about the incidence and risk factors for bloodstream infection (BSI) in patients with severe acute respiratory distress syndrome (ARDS) supported by veno–venous extracorporeal membrane oxygenation (VV–ECMO).

Methods

Patients who were diagnosed with severe ARDS and received VV–ECMO treatment in the medical intensive care unit of China–Japan Friendship Hospital from August 2013 to March 2019 were retrospectively studied. The pathogens isolated from blood culture (BC) were identified and analyzed for drug sensitivity. The risk factors for BSI were analyzed by logistic regression.

Results

A total of 105 patients were included in this single–center retrospective cohort study. Among them, 23 patients (22%) had BSIs. 19 cases were identified as primary BSI; while the other 4 cases were as secondary BSI. A total of 23 pathogenic strains were isolated from BCs, including gram–negative (G^–) bacilli in 21 (91%) cases, gram–positive (G⁺) cocci in 1 case, fungus in 1 case, and multidrug–resistant (MDR) organisms in 8 cases. Compared with patients without BSI, patients with BSI had a higher Murray score (odds ratio = 6.29, P = 0.01) and more blood transfusion (odds ratio = 1.27, P = 0.03) during ECMO.

Conclusions

The incidence of BSI in patients with severe ARDS supported by VV–ECMO was 22%. G^– bacilli was the main pathogen, and most of them were MDR–G^– bacilli (MDR–GNB). Higher Murray score and more blood transfusion may be the independent risk factors for BSI.

Association of red blood cell and platelet transfusions with persistent inflammation, immunosuppression, and catabolism syndrome in critically ill patients

The objective of this single-center retrospective cohort study was to investigate the relationship between blood transfusion and persistent inflammation, immunosuppression, and catabolism syndrome (PIICS). The study was conducted at the Critical Care Center at Toho University Omori Medical Center, Japan. We included 391 patients in the PIICS group (hospitalization for > 15 days, C-reactive protein > 3.0 mg/dL or albumin < 3.0 mg/dL or lymph < 800/μL on day 14) and 762 patients in the non-PIICS group (hospitalization for > 15 days and not meeting the PIICS criteria). We performed univariate and multivariate logistic regression analyses using PIICS as the objective variable and red blood cell (RBC) or fresh frozen plasma or platelet (PLT) transfusion and other confounding factors as explanatory variables. In addition, we conducted a sensitivity analysis using propensity score matching analysis. The multivariate and propensity score analyses showed that RBC and PLT transfusions were significantly associated with PIICS. This is the first study to report an association between RBC and PLT transfusions and PIICS. Our findings have contributed to better understanding the risk factors of PIICS and suggest that physicians should consider the risk of PIICS occurrence when administering blood transfusions in intensive care unit (ICU) patients.

Impact of Blood Product Transfusions on the Risk of ICU-Acquired Infections in Septic Shock

OBJECTIVES

Transfusions of blood products are common in critically ill patients and have a potential for immunomodulation. The aim of this study is to address the impact of transfusion of blood products on the susceptibility to ICU-acquired infections in the high-risk patients with septic shock.

DESIGN

A single-center retrospective study over a 10-year period (2008-2017).

SETTING

A medical ICU of a tertiary-care center.

PATIENTS

All consecutive patients diagnosed for septic shock within the first 48 hours of ICU admission were included. Patients who were discharged or died within the first 48 hours were excluded.

INTERVENTIONS

RBC, platelet, and fresh frozen plasma transfusions collected up to 24 hours prior to the onset of ICU-acquired infection.

MEASUREMENTS AND MAIN RESULTS

During the study period, 1,152 patients were admitted for septic shock, with 893 patients remaining alive in the ICU after 48 hours of management. A first episode of ICU-acquired infection occurred in 28.3% of the 48-hour survivors, with a predominance of pulmonary infections (57%). Patients with ICU-acquired infections were more likely to have received RBC, platelet, and fresh frozen plasma transfusions. In a multivariate Cox cause-specific analysis, transfusions of platelets (cause-specific hazard ratio = 1.55 [1.09-2.20]; p = 0.01) and fresh frozen plasma (cause-specific hazard ratio = 1.38 [0.98-1.92]; p = 0.05) were independently associated with the further occurrence of ICU-acquired infections.

CONCLUSIONS

Transfusions of platelets and fresh frozen plasma account for risk factors of ICU-acquired infections in patients recovering from septic shock. The occurrence of ICU-acquired infections should be considered as a relevant endpoint in future studies addressing the indications of transfusions in critically ill patients.

Anemia and red blood cell transfusion practice in prolonged mechanically ventilated patients admitted to a specialized weaning center: an observational study

Background

The impact of anemia and red blood cell (RBC) transfusion on weaning from mechanical ventilation is not known. In theory, transfusions could facilitate liberation from the ventilator by improving oxygen transport capacity. In contrast, retrospective studies of critically ill patients showed a positive correlation of transfusions with prolonged mechanical ventilation, increased mortality rates, and increased risk of nosocomial infections, which in turn could adversely affect weaning outcome.

Methods

Retrospective, observational study on prolonged mechanically ventilated, tracheotomized patients (n = 378), admitted to a national weaning center over a 5 year period. Medical records were reviewed to obtain data on patients’ demographics, comorbidities, blood counts, transfusions, weaning outcome, and nosocomial infections, defined according to the criteria of the U.S. Centers for Disease Control and Prevention. The impact of RBC transfusion on outcome measures was assessed using regression models.

Results

Ninety-eight percent of all patients showed anemia on admission to the weaning center. Transfused and non-transfused patients differed significantly regarding disease severity and comorbidities. In multivariate analyses, RBC transfusion, but not mean hemoglobin concentration in the course of weaning, was independently correlated with weaning duration (adjusted β 12.386, 95% CI 9.335–15.436; p <  0.001) and hospital length of stay (adjusted β 16.116, 95% CI 8.925–23.306; p <  0.001); there was also a trend toward increased hospital mortality (adjusted odds ratio [OR] 2.050, 95% CI 0.995–4.224; p = 0.052), but there was no independent correlation with weaning outcome or nosocomial infections. In contrast, hemoglobin level on the day of admission to the weaning center was independently associated with hospital mortality (adjusted OR 0.956, 95% CI 0.924–0.989; p = 0.010), appearing significantly elevated at values below 8.5 g/dl (AUC 0.670, 95% CI 0.593–0.747; p <  0.001).

Conclusions

A high percentage of prolonged mechanically ventilated patients showed anemia on admission to the weaning center. RBC transfusion was independently correlated with worse outcomes. Since transfused patients differed significantly regarding their clinical characteristics and comorbidities, RBC transfusion might be an indicator of disease severity rather than directly impacting patient prognosis.

Red blood cell transfusion results in adhesion of neutrophils in human endotoxemia and in critically ill patients with sepsis

BACKGROUND

Red blood cell (RBC) transfusion is associated with adverse effects, which may involve activation of the host immune response. The effect of RBC transfusion on neutrophil Reactive Oxygen Species (ROS) production and adhesion ex vivo was investigated in endotoxemic volunteers and in critically ill patients that received a RBC transfusion. We hypothesized that RBC transfusion would cause neutrophil activation, the extent of which depends on the storage time and the inflammatory status of the recipient.

STUDY DESIGN AND METHODS

Volunteers were injected with lipopolysaccharide (LPS) and transfused with either saline, fresh, or stored autologous RBCs. In addition, 47 critically ill patients with and without sepsis receiving either fresh (<8 days) or standard stored RBC (2‐35 days) were included. Neutrophils from healthy volunteers were incubated with the plasma samples from the endotoxemic volunteers and from the critically ill patients, after which priming of neutrophil ROS production and adhesion were assessed.

RESULTS

In the endotoxemia model, ex vivo neutrophil adhesion, but not ROS production, was increased after transfusion, which was not affected by RBC storage duration. In the critically ill, ex vivo neutrophil ROS production was already increased prior to transfusion and was not increased following transfusion. Neutrophil adhesion was increased following transfusion, which was more notable in the septic patients than in non‐septic patients. Transfusion of fresh RBCs, but not standard issued RBCs, resulted in enhanced ROS production in neutrophils.

CONCLUSION

RBC transfusion was associated with increased neutrophil adhesion in a model of human endotoxemia as well as in critically ill patients with sepsis.

Propensity and impact of autologous platelet rich plasma use in acute type A dissection

BACKGROUND

Coagulopathy in patients undergoing open repair of acute type A aortic dissection using cardiopulmonary bypass and hypothermic circulatory arrest is a common complication. Autologous platelet rich plasma is an intraoperative blood conservation technique, which has been shown in previous studies to promote hemostasis, leading to a reduction of blood product transfusions during elective aortic surgery. The purpose of this study is to evaluate the effectiveness of autologous platelet rich plasma as a blood conservation technique during open surgical repair of acute type A aortic dissection.

METHODS

We reviewed all acute type A aortic dissection cases using hypothermic circulatory arrest, excluding patients presenting in extremis. Perioperative transfusion requirements and clinical outcomes were analyzed. The end points analyzed included early mortality, postoperative stroke, renal dysfunction, prolonged ventilation, coagulopathy, and length of postoperative intensive care unit stay. Parsimonious and saturated propensity scores were calculated for platelet rich plasma use, and all outcomes were propensity adjusted.

RESULTS

Between 2003 and 2014, 85 of 391 acute type A aortic dissection repairs used autologous platelet rich plasma. Mean age of patients was 58 ± 15 years, and 70% were male. Obstructive sleep apnea (22% vs 13%, P = .04) and baseline ejection fraction (57% ± 6.7% vs 55% ± 10%; P = .014) were higher in the autologous platelet rich plasma group. Intraoperative propensity-adjusted blood products, 2 units fewer packed red blood cells (P = .001), 4 units fewer fresh-frozen plasma (P = .001), 6 units fewer platelets (P = .001), 1.3 units fewer cell-savers (P = .002), and 5 units fewer cryoprecipitate (P = .001) were significantly reduced by autologous platelet rich plasma use. Significant unadjusted reduction in postoperative reoperation for bleeding (8% vs 17%, P = .046) after autologous platelet rich plasma was reported, although propensity adjustment eliminated significance (P = .079). No difference in stroke, cardiac, or renal complications was observed. Postoperative transfusion needed during the first 3 days was significantly reduced in the autologous platelet rich plasma group: 2 units fewer packed red blood cells (P = .13), 2 units fewer fresh-frozen plasma (P = .018), and 5 units fewer platelets (P = .001), when compared with those without autologous platelet rich plasma. Ventilation time was reduced by 3 days (P = .002), and intensive care length of stay was reduced by 3 days (P = .063) after intraoperative autologous platelet rich plasma use.

CONCLUSIONS

The use of autologous platelet rich plasma in patients undergoing open repair of acute type A aortic dissection was associated with a reduction in intraoperative and postoperative blood transfusions, as well as decreased early postoperative morbidity.

Role of transfusions in the development of hospital-acquired urinary tract-related bloodstream infection among United States Veterans

BACKGROUND

Urinary tract-related bloodstream infection (BSI) is associated with substantial morbidity, mortality, and financial costs. We examined the role of red blood cell (RBC) transfusions on developing this condition among US Veterans.

METHODS

We conducted a matched case-control study among adult inpatients admitted to 4 Veterans Affairs hospitals. Cases were patients with a positive urine culture result obtained 48hours or longer after admission and a blood culture obtained within 14days of the urine culture, which grew the same organism. Controls included patients with a positive urine culture result who were at risk for but did not develop BSI (control group 1) and patients without a positive urine culture result who were present in the facility at the time of case diagnosis (control group 2).

RESULTS

Compared with the findings in control group 1, receipt of RBCs was not significantly associated with urinary tract-related BSI (odds ratio, 1.03; 95% confidence interval, 1.00-1.07; P = .07). However, we found increased odds of urinary tract-related BSI compared with the results in patients without infection (control group 2) (odds ratio, 1.11; 95% confidence interval, 1.06-1.17; P < .001).

CONCLUSIONS

Given the heightened risk of urinary tract-related BSI associated with receiving a greater number of RBC transfusions, adhering to recommendations to transfuse the minimum amount of blood products necessary may minimize the risk of this infection among Veterans.

Bacterial Distribution and Risk Factors of Nosocomial Blood Stream Infection in Neurologic Patients in the Intensive Care Unit

OBJECTIVE

To investigate the risk factors and analyze the distribution of pathogens to provide a basis for the prevention of nosocomial blood stream infections (BSI) and reduce the incidence and mortality of nosocomial BSI in neurologic patients.

PATIENTS AND METHODS

A retrospective chart review of neurologic patients admitted to an adult intensive care unit from January 2012 to December 2017 was conducted. Every positive blood culture, clinical demographic, microbiologic and laboratory result, as well as 28-day outcome data, were compiled on a data collection sheet. The clinical significance of each isolate was determined; in addition, the antimicrobial susceptibilities of causative pathogens and the most likely source were recorded.

RESULTS

During the five-year study period, there were 121 nosocomial BSI yielding 151 isolates in 404 neurologic patients. Eighty-one percent of nosocomial BSI were monomicrobial. Gram-positive organisms caused 67.9% of these BSI, gram-negative organisms caused 32.1%, and fungi caused 0.8%. The crude incidence rate was approximately 29.9%, and the mortality of nosocomial BSI was as high as 29.8%. Intravascular lines were the most common source of nosocomial BSI (79.3%). The most common organisms causing BSI were coagulase-negative staphylococci (CoNS; 44.6% of isolates), Staphylococcus aureus (17.4%), Klebsiella species (11.5%), and Acinetobacter spp. (11.5%). Multivariable regression analysis revealed that the use of antibiotic agents in the 90 days prior (odds ratio [OR], 5.81; 95% confidence interval [CI], 3.18-10.62; p = 0.001), brain trauma (OR, 0.28; 95% CI, 0.15-0.51; p = 0.001), and transfusion (OR, 3.02; 95% CI, 1.45-6.29; p = 0.001) were significant predictors of nosocomial BSI.

CONCLUSIONS

The incidence and mortality of nosocomial BSI were high in our neurologic patients. Strictly aseptic operations, hand hygiene, and reasonable use of transfusions and antibiotic agents are effective measures to prevent nosocomial BSI.

Red blood cell transfusion in the resuscitation of septic patients with hematological malignancies

BACKGROUND

Indications for red blood cell (RBC) transfusion in septic acute circulatory failure remain unclear. We addressed the practices and the prognostic impact of RBC transfusion in the early resuscitation of severe sepsis and septic shock in patients with hematological malignancies.

METHODS

We performed a retrospective analysis of a prospectively collected database of patients with hematological malignancies who required intensive care unit (ICU) admission in 2010-2011. Patients with a main admission diagnosis of severe sepsis or septic shock were included in the present study. We assessed RBC transfusion during the first two days as part of initial resuscitation.

RESULTS

Among the 1011 patients of the primary cohort, 631 (62.4%) were admitted to the ICU for severe sepsis (55%) or septic shock (45%). Among them, 210 (33.3%) patients received a median of 2 [interquartile 1-3] packed red cells during the first 48 h. Hemoglobin levels were lower in transfused patients at days 1 and 2 and became similar to those of non-transfused patients at day 3. Early RBC transfusion was more likely in patients with myeloid neoplasms and neutropenia. Transfused patients displayed more severe presentations as assessed by higher admission SOFA scores and blood lactate levels and the further requirements for organ failure supports. RBC transfusion within the first two days was associated with higher day 7 (20.5 vs. 13.3%, p = 0.02), in-ICU (39 vs. 25.2%, p < 0.001) and in-hospital (51 vs. 36.6%, p < 0.001) mortality rates. RBC transfusion remained independently associated with increased in-hospital mortality in multivariate logistic regression (OR 1.52 [1.03-2.26], p = 0.03) and propensity score-adjusted (OR 1.64 [1.05-2.57], p = 0.03) analysis.

CONCLUSIONS

RBC transfusion is commonly used in the early resuscitation of septic patients with hematological malignancies. Although it was preferentially provided to the most severe patients, we found it possibly associated with an increased risk of death.

Glycine Does Not Add to the Beneficial Effects of Perioperative Oral Immune-Enhancing Nutrition Supplements in High-Risk Cardiac Surgery Patients

BACKGROUND

Elderly patients and patients with a poor cardiac function have increased morbidity rates when undergoing cardiac surgery. The aim of this study was to determine whether addition of glycine to a standard preoperative oral immune-enhancing nutrition supplement (OIENS) improves outcome. Glycine-enriched OIENS was compared with 2 formulas: standard OIENS and control.

METHODS

In this double-blind, 3-armed study, patients scheduled to undergo cardiac surgery with the use of extracorporeal circulation received either the glycine-enriched OIENS (OIENS + glyc, n = 24), standard OIENS (OIENS, n = 25), or control formula (Control, n = 25) for minimally 5 preoperative days. Patients were included if they were aged 70 years or older, had a compromised left ventricular function, or were planned for mitral valve surgery. Main outcome measures were postoperative infectious morbidity, organ function, and postoperative recovery.

RESULTS

Infectious morbidity was significantly lower in both treatment groups compared with the control group (p = .02). An infection was diagnosed in 5 and 4 patients in the OIENS + glyc and OIENS groups, respectively, and in 12 control patients. Less supportive therapy was necessary to stabilize circulation in both treatment groups compared with the control group. Median length of hospital stay was 7.0, 6.5, and 8.0 days in the OIENS + glyc, OIENS, and control groups, respectively. Inflammatory responses, as measured by systemic levels of proinflammatory cytokines and surface markers on polymorphonuclear cells, were comparable for all groups.

CONCLUSIONS

Preoperative OIENS reduces postoperative infectious morbidity and results in a more stable circulation; the addition of glycine does not result in any beneficial effect over standard OIENS.

Supernatants from stored red blood cell (RBC) units, but not RBC-derived microvesicles, suppress monocyte function in vitro

BACKGROUND

We have previously shown that critically ill children transfused with red blood cells (RBCs) of longer storage durations have more suppressed monocyte function after transfusion compared to children transfused with fresher RBCs and that older stored RBCs directly suppress monocyte function in vitro, through unknown mechanisms. We hypothesized that RBC-derived microvesicles (MVs) were responsible for monocyte suppression.

STUDY DESIGN AND METHODS

To determine the role of stored RBC unit-derived MVs, we cocultured monocytes with supernatants, isolated MVs, or supernatants that had been depleted of MVs from prestorage leukoreduced RBCs that had been stored for either 7 or 30 days. Isolated MVs were characterized by electron microscopy and flow cytometry. Monocyte function after coculture experiments was measured by cytokine production after stimulation with lipopolysaccharide (LPS).

RESULTS

Monocyte function was suppressed after exposure to supernatants from 30-day RBC units compared to monocytes cultured in medium alone (LPS-induced tumor necrosis factor-α production, 17,611 ± 3,426 vs. 37,486 ± 5,598 pg/mL; p = 0.02). Monocyte function was not suppressed after exposure to MV fractions. RBC supernatants that had been depleted of MVs remained immunosuppressive. Treating RBC supernatants with heat followed by RNase (to degrade protein-bound RNA) prevented RBC supernatant-induced monocyte suppression.

CONCLUSION

Our findings implicate soluble mediators of stored RBC-induced monocyte suppression outside of MV fractions and suggest that extracellular protein-bound RNAs (such as microRNA) may play a role in transfusion-related immunomodulation.

Topical antibiotics as a major contextual hazard toward bacteremia within selective digestive decontamination studies: a meta-analysis

BACKGROUND

Among methods for preventing pneumonia and possibly also bacteremia in intensive care unit (ICU) patients, Selective Digestive Decontamination (SDD) appears most effective within randomized concurrent controlled trials (RCCT's) although more recent trials have been cluster randomized. However, of the SDD components, whether protocolized parenteral antibiotic prophylaxis (PPAP) is required, and whether the topical antibiotic actually presents a contextual hazard, remain unresolved. The objective here is to compare the bacteremia rates and patterns of isolates in SDD-RCCT's versus the broader evidence base.

METHODS

Bacteremia incidence proportion data were extracted from component (control and intervention) groups decanted from studies investigating antibiotic (SDD) or non-antibiotic methods of VAP prevention and summarized using random effects meta-analysis of study and group level data. A reference category of groups derived from purely observational studies without any prevention method under study provided a benchmark incidence.

RESULTS

Within SDD RCCTs, the mean bacteremia incidence among concurrent component groups not exposed to PPAP (27 control; 17.1%; 13.1-22.1% and 12 intervention groups; 16.2%; 9.1-27.3%) is double that of the benchmark bacteremia incidence derived from 39 benchmark groups (8.3; 6.8-10.2%) and also 20 control groups from studies of non-antibiotic methods (7.1%; 4.8 - 10.5). There is a selective increase in coagulase negative staphylococci (CNS) but not in Pseudomonas aeruginosa among bacteremia isolates within control groups of SDD-RCCT's versus benchmark groups with data available.

CONCLUSIONS

The topical antibiotic component of SDD presents a major contextual hazard toward bacteremia against which the PPAP component partially mitigates.

Red blood cell transfusion and immune function in critically ill children: a prospective observational study

BACKGROUND

Our previous in vitro work showed that stored red blood cells (RBCs) increasingly suppress markers of innate immune function with increased storage time. This multicenter prospective observational study tests the hypothesis that a single RBC transfusion in critically ill children is associated with immune suppression as a function of storage time.

STUDY DESIGN AND METHODS

Blood samples were taken immediately before and 24 (±6) hours after a single RBC transfusion ordered as part of routine care. Innate and adaptive immune function was assessed by ex vivo whole blood stimulation with lipopolysaccharide (LPS) and phytohemagglutinin, respectively. Monocyte HLA-DR expression, regulatory T cells, plasma interleukin (IL)-6, and IL-8 levels were also measured.

RESULTS

Thirty-one transfused critically ill children and eight healthy controls were studied. Critically ill subjects had lower pretransfusion LPS-induced tumor necrosis factor-α production capacity compared to healthy controls, indicating innate immune suppression (p < 0.0002). Those who received RBCs stored for not more than 21 days demonstrated recovery of innate immune function (p = 0.02) and decreased plasma IL-6 levels (p = 0.002) over time compared to children transfused with older blood, who showed persistence of systemic inflammation and innate immune suppression. RBC storage time was not associated with changes in adaptive immune function.

CONCLUSION

In this pilot cohort of critically ill children, transfusion with older prestorage leukoreduced RBCs was associated with persistence of innate immune suppression and systemic inflammation. This was not seen with fresher RBCs. RBC transfusion had no short-term association with adaptive immune function. Further studies are warranted to confirm these findings in a larger cohort of patients.

Red blood cell transfusion in patients with traumatic brain injury: a systematic review protocol

BACKGROUND

Anemia is a prevalent condition in critically ill patients and red blood cell transfusions are frequent. Although transfusions at low hemoglobin levels have been shown to be associated with equivalent or better outcomes than higher hemoglobin thresholds, clinical equipoise persists in patients with traumatic brain injury considering their susceptibility to secondary cerebral insults such as those from hypoxemia.

METHODS

Our objectives are to estimate the frequency of red blood cell transfusion in patients with traumatic brain injury and to evaluate transfusion thresholds, determinants and outcomes associated with transfusion strategies.We will conduct a systematic review of cohort studies and randomized controlled trials of patients with traumatic brain injury. We will search MEDLINE, Embase, BIOSIS and the Cochrane Library for eligible studies. Two independent reviewers will screen all identified references. Studies including adult patients with traumatic brain injury reporting data on red blood cell transfusions will be eligible. We will collect data on baseline demographics, trauma characteristics, hemoglobin thresholds, blood transfusions and clinical outcomes (mortality, length of stay, complications, and so on). Two independent reviewers will extract data using a standardized form. We will pool cumulative incidences using DerSimonian and Lair random-effect models after a Freeman-Tukey transformation to stabilize variances. We will pool risk ratios or mean differences with random-effect models and Mantel-Haenszel or inverse variance methods in order to evaluate the association between red blood cell transfusion and potential determinants or outcomes. Sensitivity and subgroup analysis according to timing of red blood cell transfusion, traumatic brain injury severity, year of conduction of the study, risk of bias, notably, are planned.

DISCUSSION

We expect to observe high heterogeneity in the proportion of transfused patients across studies and that the global proportion will be similar to the frequency observed in the general medical critically ill population. Our systematic review will allow us to better describe and understand current transfusion practices in patients with traumatic brain injury, a clinical population in which liberal transfusions are still advocated in the absence of evidence-based data.

SYSTEMATIC REVIEW REGISTRATION PROSPERO

CRD42014007402.

Bacteremia and ventilator-associated pneumonia: a marker for contemporaneous extra-pulmonic infection

BACKGROUND

Ventilator-associated pneumonia (VAP) is a well-known complication of mechanical ventilation in severely injured patients. A subset of patients with VAP develop an associated bacteremia (B-VAP), but the risk factors, microbiology, morbidity, and mortality in this group are not well described. The goal of this study was to examine the incidence, predictors, and outcome of B-VAP in adult trauma patients.

METHODS

We conducted a retrospective review of trauma patients who developed VAP or B-VAP from January 2007 to December 2009 at a single, university-affiliated medical center. Ventilator-associated pneumonia was defined as a clinician-documented instance of VAP together with confirmed positive respiratory cultures (bronchoalveolar lavage [BAL] fluid specimen with ≥10(4) colony forming units (CFU)/mL or tracheal aspirate with moderate-to-many organisms and polymorphonuclear neutrophils [PMN]). Bacteremia associated with VAP (B-VAP) was defined as the blood culture of an organism that matched the pulmonary pathogen in a case of VAP. We reviewed the demographic data, injury severity, transfusion data, and microbiology of patients who developed VAP and B-VAP. Outcome data included the number of days of care in the intensive care unit (ICU) and hospital length of stay, number of days of mechanical ventilation, and survival. A Student t-test, χ(2) test, or logistic regression was used as appropriate for data analysis.

RESULTS

During the 36-mo period of the study, 4,018 adult patients were admitted to the hospital. Ventilator-associated pneumonia was diagnosed in 206 (5%) of these patients, and 26 of these latter patients (13%) had an associated bacteremia. The mean time from admission to the development of VAP was 5 d (95% CI 4.6-5.8). Patients who had B-VAP received significantly more units of red blood cell concentrates (PRBC) than those who did not have B-VAP (23 units vs. 9 units of PRBC, respectively, p<0.05). Patients with B-VAP also had higher rates of simultaneous non-pulmonary infections than those with VAP alone (69% vs. 38%, respectively), a greater number of days of mechanical ventilator support (24 d vs. 14 d, respectively, p<0.05), a greater number of days in the ICU (26 d vs. 17 d, respectively, p<0.05), and a greater hospital length of stay (50 d vs. 30 d, respectively, p<0.05). Patients with B-VAP showed a trend toward lower survival than those without B-VAP, but B-VAP was not an independent predictor of mortality.

CONCLUSIONS

Trauma patients with B-VAP have a similar mortality but greater morbidity than those with VAP alone. The number of PRBC received is the most significant risk factor for developing B-VAP. More than two-thirds of patients with B-VAP have contemporaneous extra-pulmonic infections. Trauma patients with B-VAP may benefit from increased surveillance for additional concomitant infections and from more aggressive empiric antimicrobial coverage.

Diabetes mellitus and community-acquired bloodstream infections in the critically ill

INTRODUCTION

Community-acquired bloodstream infections have not been studied related to diabetes mellitus in the critically ill.

HYPOTHESIS

We hypothesized that the diagnosis of diabetes mellitus and poor chronic glycemic control would increase the risk of community-acquired bloodstream infections (CA-BSIs) in the critically ill.

METHODS

We performed an observational cohort study between 1998 and 2007 in 2 teaching hospitals in Boston, Massachusetts. We studied 2551 patients 18 years or older, who received critical care within 48 hours of admission and had blood cultures obtained within 48 hours of admission. The exposure of interest was diabetes mellitus defined by International Classification of Diseases, Ninth Revision, Clinical Modification, code 250.xx in outpatient or inpatient records. The primary end point was CA-BSI (<48 hours of hospital admission). Patients with a single coagulase-negative Staphylococcus positive blood culture were not considered to have bloodstream infection. Associations between diabetes groups and bloodstream infection were estimated by bivariable and multivariable logistic regression models. Subanalyses included evaluation of the association between hemoglobin A1c (HbA1c) and bloodstream infection, diabetes and risk of sepsis, and the proportion of the association between diabetes and CA-BSI that was mediated by acute glycemic control.

RESULTS

Diabetes is a predictor of CA-BSI. After adjustment for age, sex, race, patient type (medical vs surgical), and acute organ failure, the risk of bloodstream infection was significantly higher in patients with diabetes (odds ratio [OR], 1.42; 95% confidence interval [CI], 1.10-1.82; P = .006) relative to patients without diabetes. The adjusted risk of bloodstream infection was increased in patients with HbA1c of 6.5% or higher (OR, 1.31; 95% CI, 1.04-1.65; P = .02) relative to patients with HbA1c less than 6.5%. Furthermore, the adjusted risk of sepsis was significantly higher in patients with diabetes (OR, 1.26; 95% CI, 1.04-1.54; P = .02) relative to patients without diabetes. Maximum glucose did not significantly mediate the relationship between diabetes mellitus diagnosis and CA-BSI.

CONCLUSIONS

A diagnosis of diabetes mellitus and HbA1c of 6.5% or higher is associated with the risk of CA-BSI in the critically ill.

Association between prehospital vitamin D status and hospital-acquired bloodstream infections

BACKGROUND

Alterations in immune function can predispose patients to nosocomial infections. Few studies have explored potentially modifiable host factors that may improve immune function and decrease risk of hospital-acquired bloodstream infection (HABSI). Vitamin D is a key regulator of innate and adaptive immune systems that may influence host susceptibility to infections.

OBJECTIVE

We investigated the association between prehospital serum 25-hydroxyvitamin D [25(OH)D] concentrations and risk of HABSI.

DESIGN

We performed a retrospective cohort study of 2135 adult patients from 2 Boston teaching hospitals. All patients had 25(OH)D concentrations measured before hospitalization between 1993 and 2010. The main outcome measure was HABSI, which was defined as positive blood cultures from samples drawn 48 h after hospital admission. Coagulase-negative Staphylococcus isolates were not considered to be bloodstream infections. Associations between 25(OH)D groups and HABSI were estimated by using bivariable and multivariable logistic regression models. Adjusted ORs were estimated with the inclusion of covariate terms thought to plausibly interact with both 25(OH)D concentration and HABSI.

RESULTS

Compared with patients with 25(OH)D concentrations ≥30 ng/mL, patients with concentrations <30 ng/mL had higher odds of HABSI. For 25(OH)D concentrations <10 ng/mL, the OR was 2.33 (95% CI: 1.45, 3.74); for 25(OH)D concentrations from 10 to 19.9 ng/mL, the OR was 1.60 (95% CI: 1.04, 2.46); and for 25(OH)D concentrations from 20 to 29.9 ng/mL, the OR was 1.13 (95% CI: 0.69, 1.84). After adjustment for age, sex, race (nonwhite compared with white), patient type (medical compared with surgical), and Deyo-Charlson index, the ORs of HABSI were 1.95 (95% CI: 1.22, 3.12), 1.36 (95% CI: 0.89, 2.07), and 0.98 (95% CI: 0.60, 1.62), respectively.

CONCLUSIONS

The analysis of 2135 adult patients showed that 25(OH)D concentrations <10 ng/mL before hospitalization were associated with significantly increased odds of developing HABSI. These data support the initiation of randomized trials to test the role of vitamin D supplementation in HABSI prevention.

The association between red blood cell and platelet transfusion and subsequently developing idiopathic pneumonia syndrome after hematopoietic stem cell transplantation

BACKGROUND

Blood transfusions are common during hematopoietic stem cell transplantation (HSCT) and may contribute to lung injury.

STUDY DESIGN AND METHODS

This study examined the associations between red blood cell (RBC) and platelet (PLT) transfusions and idiopathic pneumonia syndrome (IPS) among 914 individuals who underwent myeloablative allogeneic HSCT between 1997 and 2001. Patients received allogeneic blood transfusions at their physicians' discretion. RBCs, PLTs, and a composite of "other" transfusions were quantified as the sum of units received each 7-day period from 6 days before transplant until IPS onset, death, or Posttransplant Day 120. RBC and PLT transfusions were modeled as separate time-varying exposures in proportional hazards models adjusted for IPS risk factors (age, baseline disease, irradiation dose) and other transfusions. Timing of PLT transfusion relative to myeloid engraftment and PLT ABO blood group (match vs. mismatch) were included as potential interaction terms.

RESULTS

Patients received a median of 9 PLT and 10 RBC units. There were 77 IPS cases (8.4%). Each additional PLT unit transfused in the prior week was associated with 16% higher IPS risk (hazard ratio, 1.16; 95% confidence interval, 1.09-1.23; p < 0.001). Recent RBC and PLT transfusions were each significantly associated with greater risk of IPS when examined without the other; only PLT transfusions retained significance when both exposures were included in the model. The PLT association was not modified by engraftment or ABO mismatch.

CONCLUSION

PLT transfusions are associated with greater risk of IPS after myeloablative HSCT. RBCs may also contribute; however, these findings need confirmation.

Red blood cell transfusion is associated with decreased in-hospital muscle strength among critically ill patients requiring mechanical ventilation

PURPOSE

Red blood cell (RBC) transfusion is linked to poor functional recovery after surgery and trauma. To investigate one potential mechanism, we examined the association between RBC transfusion and muscle strength in a cohort of critically ill patients.

METHODS

We performed a secondary analysis of 124 critically ill, mechanically ventilated patients enrolled in 2 prospective cohort studies where muscle strength testing was performed at a median of 12 days after mechanical ventilation onset. We examined the association between RBC transfusion and dynamometry handgrip strength using multivariable linear regression, adjusting for study site, age, sex, Acute Physiology and Chronic Health Evaluation, Sequential Organ Failure Assessment score, days from hospital admission to examination, and steroid use. Secondary outcomes included systematic manual muscle strength and intensive care unit-acquired paresis.

RESULTS

Among 124 subjects, 73 (59%) received RBC transfusion in the 30 days before examination. In adjusted analyses, RBC transfusion was significantly associated with weaker handgrip (adjusted mean difference, -9.9 kg; 95% confidence interval, -16.6 to -3.2; P < .01) and proximal manual muscle strength (adjusted mean difference in Medical Research Council score, -0.5; 95% confidence interval, -0.7 to -0.2; P < .01) but not intensive care unit-acquired paresis.

CONCLUSIONS

Red blood cell transfusion was associated with decreased muscle strength in this cohort of critically ill patients after adjusting for illness severity and organ dysfunction. Further studies are needed to validate these results and probe mechanisms.

Anemia and blood transfusions in critically ill patients

Anemia is common in critically ill patients. As a consequence packed red blood cell (PRBC) transfusions are frequent in the critically ill. Over the past two decades a growing body of literature has emerged, linking PRBC transfusion to infections, immunosuppression, organ dysfunction, and a higher mortality rate. However, despite growing evidence that risk of PRBC transfusion outweighs its benefit, significant numbers of critically ill patients still receive PRBC transfusion during their intensive care unit (ICU) stay. In this paper, we summarize the current literature concerning the impact of anemia on outcomes in critically ill patients and the potential complications of PRBC transfusions.

Transfusion of packed red blood cells is not associated with improved central venous oxygen saturation or organ function in patients with septic shock

BACKGROUND

The exact role of packed red blood cell (PRBC) transfusion in the setting of early resuscitation in septic shock is unknown.

STUDY OBJECTIVE

To evaluate whether PRBC transfusion is associated with improved central venous oxygen saturation (ScvO(2)) or organ function in patients with severe sepsis and septic shock receiving early goal-directed therapy (EGDT).

METHODS

Retrospective cohort study (n=93) of patients presenting with severe sepsis or septic shock treated with EGDT.

RESULTS

Thirty-four of 93 patients received at least one PRBC transfusion. The ScvO(2) goal>70% was achieved in 71.9% of the PRBC group and 66.1% of the no-PRBC group (p=0.30). There was no difference in the change in Sequential Organ Failure Assessment (SOFA) score within the first 24 h in the PRBC group vs. the no-PRBC group (8.6-8.3 vs. 5.8-5.6, p=0.85), time to achievement of central venous pressure>8 mm Hg (732 min vs. 465 min, p=0.14), or the use of norepinephrine to maintain mean arterial pressure>65 mm Hg (81.3% vs. 83.8%, p=0.77).

CONCLUSIONS

In this study, the transfusion of PRBC was not associated with improved cellular oxygenation, as demonstrated by a lack of improved achievement of ScvO(2)>70%. Also, the transfusion of PRBC was not associated with improved organ function or improved achievement of the other goals of EGDT. Further studies are needed to determine the impact of transfusion of PRBC within the context of early resuscitation of patients with septic shock.

Red blood cell transfusion in the neurological ICU

Red blood cell transfusion (RBCT) is a common therapy used in the intensive care unit to treat anemia. However, due to deleterious side effects and questionable efficacy, the clinical benefit of RBCT in patients who are not actively bleeding is unclear. The results of randomized controlled trials suggest there is no benefit to a liberal transfusion practice in general critical care populations. Whether the results of these trials are applicable to brain injured patients is unknown, as patients with primary neurological injury were excluded. This article reviews the efficacy and complications of RBCT, as well as the relationship between RBCT and its outcome in both the general intensive care unit and neurologically critically ill populations.

Immunosuppressive effects of red blood cells on monocytes are related to both storage time and storage solution

BACKGROUND

Reduced monocyte function is associated with adverse outcomes from critical illness. Red blood cells (RBCs) are thought to impair monocyte function but relationships between RBC storage solution and monocyte suppression are unknown. This study was designed to test the hypothesis that immunosuppressive effects of RBCs on monocytes are related to both storage time and preservative solution.

STUDY DESIGN AND METHODS

Monocytes from healthy adult donors were co-cultured with RBCs that had been stored in AS-1, AS-3, or CPD only for 7, 14, or 21 days. Cells were then stimulated with lipopolysaccharide (LPS) and their supernatants assayed for tumor necrosis factor (TNF)-α and interleukin (IL)-10. Transwell experiments were performed to evaluate the role of cell-to-cell contact. Monocyte mRNA expression was quantified by real-time-polymerase chain reaction.

RESULTS

LPS-induced TNF-α production capacity was reduced compared to controls for all groups, but CPD-only RBCs suppressed monocyte function more than RBCs stored in AS-1 (p = 0.007) and AS-3 (p = 0.006). IL-10 production was preserved or augmented in all groups. A longer storage time was associated with reduced TNF-α production capacity for AS-1 and AS-3 groups but not CPD. Preventing cell-to-cell contact did not eliminate the inhibitory effect of RBCs on monocyte responsiveness. RBC exposure was associated with decreased LPS-induced TNFA mRNA expression (p < 0.05 for all groups).

CONCLUSIONS

CPD-only RBCs suppressed monocyte function more than RBCs stored with additive solutions. TNF-α production was reduced even in the absence of cell-to-cell contact and was impaired at the mRNA level. Further work is needed to understand the role of preservative solutions in this process.

Red blood cell transfusion and outcomes in patients with acute lung injury, sepsis and shock

Introduction

In this study, we sought to determine the association between red blood cell (RBC) transfusion and outcomes in patients with acute lung injury (ALI), sepsis and shock.

Methods

We performed a secondary analysis of new-onset ALI patients enrolled in the Acute Respiratory Distress Syndrome Network Fluid and Catheter Treatment Trial (2000 to 2005) who had a documented ALI risk factor of sepsis or pneumonia and met shock criteria (mean arterial pressure (MAP) < 60 mmHg or vasopressor use) within 24 hours of randomization. Using multivariable logistic regression, we examined the association between RBC transfusion and 28-day mortality after adjustment for age, sex, race, randomization arm and Acute Physiology and Chronic Health Evaluation III score. Secondary end points included 90-day mortality and ventilator-free days (VFDs). Finally, we examined these end points among the subset of subjects meeting prespecified transfusion criteria defined by five simultaneous indicators: hemoglobin < 10.2 g/dL, central or mixed venous oxygen saturation < 70%, central venous pressure ≥ 8 mmHg, MAP ≥ 65 mmHg, and vasopressor use.

Results

We identified 285 subjects with ALI, sepsis, shock and transfusion data. Of these, 85 also met the above prespecified transfusion criteria. Fifty-three (19%) of the two hundred eighty-five subjects with shock and twenty (24%) of the subset meeting the transfusion criteria received RBC transfusion within twenty-four hours of randomization. We found no independent association between RBC transfusion and 28-day mortality (odds ratio = 1.49, 95% CI (95% confidence interval) = 0.77 to 2.90; P = 0.23) or VFDs (mean difference = -0.35, 95% CI = -4.03 to 3.32; P = 0.85). Likewise, 90-day mortality and VFDs did not differ by transfusion status. Among the subset of patients meeting the transfusion criteria, we found no independent association between transfusion and mortality or VFDs.

Conclusions

In patients with new-onset ALI, sepsis and shock, we found no independent association between RBC transfusion and mortality or VFDs. The physiological criteria did not identify patients more likely to be transfused or to benefit from transfusion.

Red cell distribution width and all-cause mortality in critically ill patients

OBJECTIVE

Red cell distribution width is a predictor of mortality in the general population. The prevalence of increased red cell distribution width and its significance in the intensive care unit are unknown. The objective of this study was to investigate the association between red cell distribution width at the initiation of critical care and all cause mortality.

DESIGN

Multicenter observational study.

SETTING

Two tertiary academic hospitals in Boston, MA.

PATIENTS

A total of 51,413 patients, aged ≥ 18 yrs, who received critical care between 1997 and 2007.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The exposure of interest was red cell distribution width as a predictor of mortality in the general population. The prevalence of increased red cell distribution width and its significance in the intensive care unit are unknown and categorized a priori in quintiles as ≤ 13.3%, 13.3% to 14.0%, 14.0% to 14.7%, 14.7% to 15.8%, and >15.8%. Logistic regression examined death by days 30, 90, and 365 postcritical care initiation, inhospital mortality, and bloodstream infection. Adjusted odds ratios were estimated by multivariable logistic regression models. Adjustment included age, sex, race, Deyo-Charlson index, coronary artery bypass grafting, myocardial infarction, congestive heart failure, hematocrit, white blood cell count, mean corpuscular volume, blood urea nitrogen, red blood cell transfusion, sepsis, and creatinine. Red cell distribution width was a particularly strong predictor of all-cause mortality 30 days after critical care initiation with a significant risk gradient across red cell distribution width quintiles after multivariable adjustment: red cell distribution width 13.3% to 14.0% (odds ratio [OR], 1.19; 95% confidence interval [CI], 1.08-1.30; p <.001); red cell distribution width 14.0% to 14.7% (OR, 1.28; 95% CI, 1.16-1.42; p <.001); red cell distribution width 14.7% to 15.8% (OR, 1.69; 95% CI, 1.52-1.86; p <.001); red cell distribution width >15.8% (OR, 2.61; 95% CI, 2.37-2.86; p <.001), all relative to patients with red cell distribution width ≤ 13.3%. Similar significant robust associations postmultivariable adjustments are seen with death by days 90 and 365 postcritical care initiation as well as inhospital mortality. In a subanalysis of patients with blood cultures drawn (n = 18,525), red cell distribution width at critical care initiation was associated with the risk of bloodstream infection and remained significant after multivariable adjustment. The adjusted risk of bloodstream infection was 1.40- and 1.44-fold higher in patients with red cell distribution width values in the 14.7% to 15.8% and >15.8% quintiles, respectively, compared with those with red cell distribution width ≤ 13.3%. Estimating the receiver operating characteristic area under the curve shows that red cell distribution width has moderate discriminative power for 30-day mortality (area under the curve = 0.67).

CONCLUSION

Red cell distribution width is a robust predictor of the risk of all-cause patient mortality and bloodstream infection in the critically ill. Red cell distribution width is commonly measured, inexpensive, and widely available and may reflect overall inflammation, oxidative stress, or arterial underfilling in the critically ill.

Red blood cell transfusion thresholds in pediatric patients with sepsis

OBJECTIVES

In children with severe sepsis or septic shock, the optimal red blood cell transfusion threshold is unknown. We analyzed the subgroup of patients with sepsis and transfusion requirements in a pediatric intensive care unit study to determine the impact of a restrictive vs. liberal transfusion strategy on clinical outcome.

DESIGN

Subgroup analysis of a prospective, multicenter, randomized, controlled trial.

SETTING

Multicenter pediatric critical care units.

PATIENTS

Stabilized critically ill children (mean systemic arterial pressure >2 sd below normal mean for age and cardiovascular support not increased for at least 2 hrs before enrollment) with a hemoglobin ≤ 9.5 g/dL within 7 days after pediatric critical care unit admission.

INTERVENTIONS

One hundred thirty-seven stabilized critically ill children with sepsis were randomized to receive red blood cell transfusion if their hemoglobin decreased to either <7.0 g/dL (restrictive group) or 9.5 g/dL (liberal group).

MEASUREMENTS AND MAIN RESULTS

In the restrictive group (69 patients), 30 patients did not receive any red blood cell transfusion, whereas only one patient in the liberal group (68 patients) never underwent transfusion (p < .01). No clinically significant differences were found for the occurrence of new or progressive multiple organ dysfunction syndrome (18.8% vs. 19.1%; p = .97), for pediatric critical care unit length of stay (p = .74), or for pediatric critical care unit mortality (p = .44) in the restrictive vs. liberal group.

CONCLUSIONS

In this subgroup analysis of children with stable sepsis, we found no evidence that a restrictive red cell transfusion strategy, as compared to a liberal one, increased the rate of new or progressive multiple organ dysfunction syndromes. Furthermore, a restrictive transfusion threshold significantly reduced exposure to blood products. Our data suggest that a hemoglobin level of 7.0 g/dL may be safe stabilized for children with sepsis, but further studies are required to support this recommendation.

Transfusion of leukocyte-depleted red blood cells is not a risk factor for nosocomial infections in critically ill children

OBJECTIVES

Transfusion of red blood cells is increasingly linked with adverse outcomes in critically ill children. We tested the hypothesis that leukocyte-depleted red blood cell transfusions were independently associated with increased development of bloodstream infections, ventilator-associated pneumonias, or urinary tract infections.

DESIGN

Historical, descriptive cohort study.

SETTING

Single-center, mixed medical-surgical, closed nine-bed pediatric intensive care unit of a tertiary university hospital.

PATIENTS

All children <18 yrs of age consecutively admitted to the pediatric intensive care unit during a 3-yr period (January 1, 2005, to December 31, 2007).

INTERVENTIONS

None.

RESULTS

One thousand one hundred twenty-three patients were admitted, of whom 503 (44.8%) were admitted for >48 hrs. Sixty-five (12.9%) had a nosocomial infection (incidence 19.3 per 1,000 pediatric intensive care unit admissions per year). Patients with a nosocomial infection were significantly more often male (72.3% vs. 27.7%, p = .033), had a higher Pediatric Risk of Mortality II score (median 19.1 [range, 6-44] vs. 18.0 [range, 2-39], p = .023), were more often ventilated (95.4% vs. 80.1%, p = .003), and received more often red blood cell transfusions (55.4% vs. 40.2%, p = .021). Multivariate logistic regression analysis showed that male gender (odds ratio, 2.07; 95% confidence interval, 1.14-3.76), presence of an indwelling central venous catheter (odds ratio, 2.41; 95% confidence interval, 1.29-4.48), and simultaneous use of more than one type of antimicrobial drug were independently associated with the development of nosocomial infections. Red blood cell transfusion was discarded as a predictor.

CONCLUSIONS

Transfusion of leukocyte-depleted red blood cells was not independently associated with the development of nosocomial infections in a heterogeneous group of critically ill children.

Effect of a blood conservation device in patients with preserved admission haemoglobin in the intensive care unit

An important iatrogenic cause of anaemia in the intensive care unit is loss of the discarded blood during phlebotomy via indwelling vascular catheters. A closed system blood conservation device has previously been shown to reduce the need for blood transfusion and to blunt the decrease of haemoglobin in intensive care unit patients. However such a device may not benefit patients who are admitted with a relatively preserved haemoglobin. In this sub-group analysis of a before-and-after study, 128 patients had admission haemoglobin > or =115 g/l and did not receive any blood transfusions while in the intensive care unit. In the control group of 50 patients a blood conservation device was not used, while in the active group of 78 patients the device was used. Use of the blood conservation device did not affect the haemoglobin trends when both groups were compared using the general linear model. For patients with admission haemoglobin > or = 115 g/l, use of a blood conservation device does not affect the subsequent rate of haemoglobin decline in the intensive care unit. These patients are unlikely to benefit from the use of such devices.

Elevation of blood urea nitrogen is predictive of long-term mortality in critically ill patients independent of "normal" creatinine

OBJECTIVE

We hypothesized that elevated blood urea nitrogen can be associated with all-cause mortality independent of creatinine in a heterogeneous critically ill population.

DESIGN

Multicenter observational study of patients treated in medical and surgical intensive care units.

SETTING

Twenty intensive care units in two teaching hospitals in Boston, MA.

PATIENTS

A total of 26,288 patients, age ≥ 18 yrs, hospitalized between 1997 and 2007 with creatinine of 0.80-1.30 mg/dL.

INTERVENTIONS

None.

MEASUREMENTS

Blood urea nitrogen at intensive care unit admission was categorized as 10-20, 20-40, and >40 mg/dL. Logistic regression examined death at days 30, 90, and 365 after intensive care unit admission as well as in-hospital mortality. Adjusted odds ratios were estimated by multivariable logistic regression models.

MAIN RESULTS

Blood urea nitrogen at intensive care unit admission was predictive for short- and long-term mortality independent of creatinine. Thirty days following intensive care unit admission, patients with blood urea nitrogen of >40 mg/dL had an odds ratio for mortality of 5.12 (95% confidence interval, 4.30-6.09; p < .0001) relative to patients with blood urea nitrogen of 10-20 mg/dL. Blood urea nitrogen remained a significant predictor of mortality at 30 days after intensive care unit admission following multivariable adjustment for confounders; patients with blood urea nitrogen of >40 mg/dL had an odds ratio for mortality of 2.78 (95% confidence interval, 2.27-3.39; p < .0001) relative to patients with blood urea nitrogen of 10-20 mg/dL. Thirty days following intensive care unit admission, patients with blood urea nitrogen of 20-40 mg/dL had an odds ratio of 2.15 (95% confidence interval, 1.98-2.33; <.0001) and a multivariable odds ratio of 1.53 (95% confidence interval, 1.40-1.68; p < .0001) relative to patients with blood urea nitrogen of 10-20 mg/dL. Results were similar at 90 and 365 days following intensive care unit admission as well as for in-hospital mortality. A subanalysis of patients with blood cultures (n = 7,482) demonstrated that blood urea nitrogen at intensive care unit admission was associated with the risk of blood culture positivity.

CONCLUSION

Among critically ill patients with creatinine of 0.8-1.3 mg/dL, an elevated blood urea nitrogen was associated with increased mortality, independent of serum creatinine.

Red blood cell transfusion following burn

A severe burn will significantly alter haematologic parameters, and manifest as anaemia, which is commonly found in patients with greater than 10% total body surface area (TBSA) involvement. Maintaining haemoglobin and haematocrit levels with blood transfusion has been the gold standard for the treatment of anaemia for many years. While there is no consensus on when to transfuse, an increasing number of authors have expressed that less blood products should be transfused. Current transfusion protocols use a specific level of haemoglobin or haematocrit, which dictates when to transfuse packed red blood cells (PRBCs). This level is known as the trigger. There is no one 'common trigger' as values range from 6 g dl(-1) to 8 g dl(-1) of haemoglobin. The aim of this study was to analyse the current status of red blood cell (RBC) transfusions in the treatment of burn patients, and address new information regarding burn and blood transfusion management. Analysis of existing transfusion literature confirms that individual burn centres transfuse at a lower trigger than in previous years. The quest for a universal transfusion trigger should be abandoned. All RBC transfusions should be tailored to the patient's blood volume status, acuity of blood loss and ongoing perfusion requirements. We also focus on the prevention of unnecessary transfusion as well as techniques to minimise blood loss, optimise red cell production and determine when transfusion is appropriate.

Transfusion practice in the intensive care unit: a 10-year analysis

BACKGROUND

Clinical guidelines recommend a restrictive transfusion strategy in nonhemorrhaging critically ill patients.

STUDY DESIGN AND METHODS

We conducted a retrospective observational study of 3533 single-admission patients, without evidence of acute coronary syndromes, hemorrhage, or hemoglobinopathy admitted to the medical intensive care unit (MICU) of a large, academic medical center.

RESULTS

MICU admission hemoglobin (Hb) level did not change significantly over the study period. The proportion of transfused patients decreased from 31.0% in 1997 to 1998 to 18.0% in 2006 to 2007 (p<0.001). Among patients receiving transfusion, the mean pretransfusion Hb level decreased over time from 7.9±1.3 to 7.3±1.3g/dL (p<0.001). These changes in practice were not accounted for by differences in patient characteristics. The mean nadir Hb level in nontransfused patients decreased from 11.2±2.2g/dL in 1997 to 1999 to 10.4±2.3g/dL in 2006 to 2007 (p<0.001). The mean number of units per patient transfused decreased during this time from 4.3±4.7 to 3.0±3.8 units (p<0.001). The proportion of transfused patients who were transfused at a Hb level of less than 7.0g/dL increased by an estimated absolute increment of 3.2% (95% CI, 2.1%-4.3%) per interval (p<0.001), and the proportion of single-unit transfusions during the first transfusion episode increased by 1.4% per interval (95% CI, 0.2 to 2.6%; p=0.03) from 40.2% in 1997 to 1998 to 53.1% in 2006 to 2007.

CONCLUSIONS

Between 1997 and 2007, important and sustained changes have occurred in our MICU physician transfusion practices, with overall reductions in the proportion of patients transfused, mean pretransfusion Hb level, and nadir Hb level in patients who were not transfused.

Are red blood cell transfusions associated with nosocomial infections in pediatric intensive care units?

OBJECTIVES

To determine whether red blood cell transfusion is similarly associated with nosocomial infections in pediatric intensive care unit patients and whether reduced lymphocyte numbers is a possible mechanism. In adult studies, red blood cell transfusions are associated with nosocomial infections.

DESIGN

Historical cohort study.

SETTING

Single-center, mixed medical-surgical, closed pediatric intensive care unit of a tertiary university-affiliated children's hospital.

PATIENTS

All patients < or = 18 yrs old admitted to the pediatric intensive care unit during a 6-month period from January 1 to July 3, 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Nosocomial infections (respiratory, urinary tract, and bloodstream infections) were the primary outcome measure and were defined as post transfusion if occurring within 14 days after red blood cell transfusion. Of the 209 subjects enrolled, 32 (15%) acquired nosocomial infections and 45 (22%) received red blood cell transfusions. Patients with versus without nosocomial infections had received red blood cell transfusions significantly more often (odds ratio, 18.0; 95% confidence interval, 7.6-45.9; p < .001). In a dose-dependence analysis, we found that patients receiving > or = 3 red blood cell transfusions had a similar prevalence of nosocomial infections compared with those receiving one to two red blood cell transfusions (61% vs. 44%, p = .365), but greater mortality (22% vs. 0%, p = .04). In a multiple logistic regression analysis controlling for gender, age, pediatric intensive care unit length of stay, presence of an invasive catheter, mechanical ventilation, and surgery, red blood cell transfusion remained independently associated with risk of nosocomial infection (odds ratio, 3.73; 95% confidence interval, 1.19-11.85, p = .023). Transfused subjects had lower absolute lymphocyte counts compared with nontransfused subjects (1605 vs. 2054/microL, p = .041), but similar total white blood cell counts (10.4 vs. 11.4 x 10/microL, p = .52).

CONCLUSION

Red blood cell transfusion in pediatric intensive care unit patients is associated with an increased risk of nosocomial infections.

Blood transfusion is associated with increased morbidity and mortality after lower extremity revascularization

BACKGROUND

Little is known about the significance of blood transfusion in patients with peripheral arterial disease. We queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to examine the effect of intraoperative blood transfusion on the morbidity and mortality in patients who underwent lower extremity revascularization.

METHODS

We analyzed data from the participant use data file containing vascular surgical cases submitted to the ACS NSQIP in 2005, 2006, and 2007 by 173 hospitals. Current procedural terminology codes were used to select lower extremity procedures that were grouped into venous graft, prosthetic graft, or thromboendarterectomy. Thirty-day outcomes analyzed were (1) mortality, (2) composite morbidity, (3) graft/prosthesis failure, (4) return to the operating room within 30 days, (5) wound occurrences, (6) sepsis or septic shock, (7) pulmonary occurrences, and (8) renal insufficiency or failure. Intraoperative transfusion of packed red blood cells was categorized as none, 1 to 2 units, and 3 or more units. Outcome rates were compared between the transfused and nontransfused groups using the chi(2) test and multivariable regression adjusting for transfusion propensity, comorbid and procedural risk.

RESULTS

A total of 8799 patients underwent lower extremity revascularization between 2005 and 2007. Mean age was 66.8 +/- 12.0 years and 5569 (63.3%) were male. Transfusion rates ranged from 14.5% in thromboendarterectomy patients to 27.1% in prosthetic bypass patients (P < .05). After adjustment for transfusion propensity and patient and procedural risks, transfusion of 1 or 2 units remained significantly predictive of mortality, composite morbidity, sepsis/shock, pulmonary occurrences, and return to the operating room. The adjusted odds ratios for 30-day mortality ranged from 1.92 (95% confidence interval [CI] 1.36-2.70) for 1 to 2 units to 2.48 (95% CI 1.55-3.98) for 3 or more units.

CONCLUSION

In a large number of patients undergoing lower extremity revascularization, we have found that there is a higher risk of postoperative mortality, pulmonary, and infectious complications after receiving intraoperative blood transfusion. Additional studies are necessary to better define transfusion triggers that balance the risk/benefit ratio for blood transfusion.

The use of a blood conservation device to reduce red blood cell transfusion requirements: a before and after study

Introduction

Anaemia and the associated need for packed red blood cell (PRBC) transfusions are common in patients admitted to the intensive care unit (ICU). Among many causes, blood losses from repeated diagnostic tests are contributory.

Methods

This is a before and after study in a medical ICU of a university hospital. We used a closed blood conservation device (Venous Arterial blood Management Protection, VAMP, Edwards Lifesciences, Irvine, CA, USA) to decrease PRBC transfusion requirements. We included all adult (≥18 years) patients admitted to the ICU with indwelling arterial catheters, who were expected to stay more than 24 hours and were not admitted for active gastrointestinal or any other bleeding. We collected data for six months without VAMP (control group) immediately followed by nine months (active group) with VAMP. A restrictive transfusion strategy in which clinicians were strongly discouraged from any routine transfusions when haemoglobin (Hb) levels were above 7.5 g/dL was adopted during both periods.

Results

Eighty (mean age 61.6 years, 49 male) and 170 patients (mean age 60.5 years, 101 male) were included in the control and active groups respectively. The groups were comparable for age, gender, Acute Physiology and Chronic Health Evaluation (APACHE) II score, need for renal replacement therapy, length of stay, and Hb levels on discharge and at transfusion. The control group had higher Hb levels on admission (12.4 ± 2.5 vs. 11.58 ± 2.8 gm/dL, P = 0.02). Use of a blood conservation device was significantly associated with decreased requirements for PRBC transfusion (control group 0.131 unit vs. active group 0.068 unit PRBC/patient/day, P = 0.02) on multiple linear regression analysis. The control group also had a greater decline in Hb levels (2.13 ± 2.32 vs. 1.44 ± 2.08 gm/dL, P = 0.02) at discharge.

Conclusions

The use of a blood conservation device is associated with 1) reduced PRBC transfusion requirements and 2) a smaller decrease in Hb levels in the ICU.

Incidence of and risk factors for nosocomial bloodstream infections in adults in the United States, 2003

BACKGROUND

Although many studies have examined nosocomial bloodstream infection (BSI), US national estimates of incidence and case-fatality rates have seldom been reported.

OBJECTIVE

The purposes of this study were to generate US national estimates of the incidence and severity of nosocomial BSI and to identify risk factors for nosocomial BSI among adults hospitalized in the United States on the basis of a national probability sample.

METHODS

This cross-sectional study used the US Nationwide Inpatient Sample for the year 2003 to estimate the incidence and case-fatality rate associated with nosocomial BSI in the total US population. Cases of nosocomial BSI were defined by using 1 or more International Classification of Diseases, 9th Revision, Clinical Modification codes in the secondary field(s) that corresponded to BSIs that occurred at least 48 hours after admission. The comparison group consisted of all patients without BSI codes in their NIS records. Weighted data were used to generate US national estimates of nosocomial BSIs. Logistic regression was used to identify independent risk factors for nosocomial BSI.

RESULTS

The US national estimated incidence of nosocomial BSI was 21.6 cases per 1,000 admissions, while the estimated case-fatality rate was 20.6%. Seven of the 10 leading causes of hospital admissions associated with nosocomial BSI were infection related. We estimate that 541,081 patients would have acquired a nosocomial BSI in 2003, and of these, 111,427 would have died. The final multivariate model consisted of the following risk factors: central venous catheter use (odds ratio [OR], 4.76), other infections (OR, 4.61), receipt of mechanical ventilation (OR, 4.97), trauma (OR, 1.98), hemodialysis (OR, 4.83), and malnutrition (OR, 2.50). The total maximum rescaled R(2) was 0.22.

CONCLUSIONS

The Nationwide Inpatient Sample was useful for estimating national incidence and case-fatality rates, as well as examining independent predictors of nosocomial BSI.

Microbiology, time course and clinical characteristics of infection in critically ill patients receiving packed red blood cell transfusion

BACKGROUND AND OBJECTIVES

Packed red blood cell transfusion has been associated with increased infection in a variety of critically ill patient populations. We evaluated the microbiology and time course of infection in transfused patients in the intensive care unit (ICU) as no data exist on these parameters.

MATERIALS AND METHODS

We performed a retrospective review of data for all patients admitted to a 24-bed medical-surgical ICU at Cooper University Hospital from July 2003 to September 2006 and entered in the Project Impact database.

RESULTS

A total of 2432 patients were admitted during the study period, of which 609 underwent transfusion. Transfused patients were more likely to develop a nosocomial infection (10.5% vs. 4.9%, P < 0.001). ICU and hospital length of stay were longer in the transfused group (P < 0.001 for both). Mortality was also greater (13.1% vs. 8.7%, P = 0.001). Transfused patients had a shorter time from hospital admission to first infection (P < 0.001) and ICU admission to first infection (P < 0.001). Multivariate analysis confirmed transfusion as an independent risk factor for infection, mortality, hospital and ICU length of stay. Methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus and Acinetobacter occurred more often in transfused patients. Acinetobacter accounted for a disproportionate share of infections among transfused patients (P < 0.001).

CONCLUSIONS

Transfused ICU patients have a higher incidence of nosocomial infection and worse outcomes. Transfused patients had a shorter onset of infection. Acinetobacter infection appears to be particularly common among these patients. Further investigation is merited to better elucidate the mechanism for these findings and their therapeutic and clinical implications.

Why an alternative to blood transfusion?

Allogeneic blood transfusions have been associated with several risks and complications and with worse outcomes in a substantial number of patient populations and clinical scenarios. Allogeneic blood is costly and difficult to procure, transport, and store. Global and local shortages are imminent. Alternatives to transfusion provide many advantages, and their use is likely to improve outcomes as safer and more effective agents are developed.