Blood product transfusion and ventilator-associated pneumonia in trauma patients

Sex dimorphisms in coagulation: Implications in trauma-induced coagulopathy and trauma resuscitation

Trauma-induced coagulopathy (TIC) is one of the leading causes of preventable death in injured patients. Consequently, it is imperative to understand the mechanisms underlying TIC and how to mitigate this mortality. An opportunity for advancement stems from the awareness that coagulation demonstrates a strong sex-dependent effect. Females exhibit a relative hypercoagulability compared to males, which persists after injury and confers improved outcomes. The mechanisms underlying sex dimorphisms in coagulation and its protective effect after injury have yet to be elucidated. This review explores sex dimorphisms in enzymatic hemostasis, fibrinogen, platelets, and fibrinolysis, with implications for resuscitation of patients with TIC.

Machine learning algorithms for prediction of ventilator associated pneumonia in traumatic brain injury patients from the MIMIC-III database

BACKGROUND

Ventilator associated pneumonia (VAP) is a common complication and associated with poor prognosis of traumatic brain injury (TBI) patients.

OBJECTIVES

This study was conducted to explore the predictive performance of different machine-learning algorithms for VAP in TBI patients.

METHODS

TBI patients receiving mechanical ventilation more than 48 hours from the Medical Information Mart for Intensive Care-III (MIMIC-III) database were eligible for the study. The VAP was confirmed based on the ICD-9 code. Included patients were separated to the training cohort and the validation cohort with a ratio of 7:3. Predictive models based on different machine learning algorithms were developed using 5-fold cross validation in the training cohort and then verified in the validation cohort by evaluating the area under the receiver operating characteristic curve (AUC), sensitivity, specificity, accuracy and F score.

RESULTS

786 TBI patients from the MIMIC-III were finally included with the VAP incidence of 44.0%. The random forest performed the best on predicting VAP in the training cohort with a AUC of 1.000. The XGBoost and AdaBoost were ranked the second and the third with a AUC of 0.915 and 0.789 in the training cohort. While the AdaBoost performed the best on predicting VAP in the validation cohort with a AUC of 0.706. The XGBoost and random forest were ranked the second and the third with the AUC of 0.685 and 0.683 in the validation cohort. Generally, the random forest and XGBoost were likely to be over-fitting while the AdaBoost was relatively stable in predicting the VAP.

CONCLUSIONS

The AdaBoost performed well and stably on predicting the VAP in TBI patients. Developing programs using AdaBoost in portable electronic devices may effectively assist physicians in assessing the risk of VAP in TBI.

Pediatric traumatic hemorrhagic shock consensus conference research priorities

BACKGROUND

Traumatic injury is the leading cause of death in children and adolescents. Hemorrhagic shock remains a common and preventable cause of death in the pediatric trauma patients. A paucity of high-quality evidence is available to guide specific aspects of hemorrhage control in this population. We sought to identify high-priority research topics for the care of pediatric trauma patients in hemorrhagic shock.

METHODS

A panel of 16 consensus multidisciplinary committee members from the Pediatric Traumatic Hemorrhagic Shock Consensus Conference developed research priorities for addressing knowledge gaps in the care of injured children and adolescents in hemorrhagic shock. These ideas were informed by a systematic review of topics in this area and a discussion of these areas in the consensus conference. Research priorities were synthesized along themes and prioritized by anonymous voting.

RESULTS

Eleven research priorities that warrant additional investigation were identified by the consensus committee. Areas of proposed study included well-designed clinical trials and evaluations, including increasing the speed and accuracy of identifying and treating hemorrhagic shock, defining the role of whole blood and tranexamic acid use, and assessment of the utility and appropriate use of viscoelastic techniques during early resuscitation. The committee recommended the need to standardize essential definitions, data elements, and data collection to facilitate research in this area.

CONCLUSION

Research gaps remain in many areas related to the care of hemorrhagic shock after pediatric injury. Addressing these gaps is needed to develop improved evidence-based recommendations for the care of pediatric trauma patients in hemorrhagic shock.

Machine Learning Model to Predict Ventilator Associated Pneumonia in patients with Traumatic Brain Injury: The C.5 Decision Tree Approach

BACKGROUND

There is paucity in the literature to predict the occurrence of Ventilator Associated Pneumonia (VAP) in patients with Traumatic Brain Injury (TBI). We aimed to build a C.5. Decision Tree (C.5 DT) machine learning model to predict VAP in patients with moderate to severe TBI.

METHODS

This was a retrospective study including all adult patients who were hospitalized with TBI plus head abbreviated injury scale (AIS) ≥ 3 and were mechanically ventilated in a level 1 trauma center between 2014 and 2019.

RESULTS

A total of 772 eligible patients were enrolled, of them 169 had VAP (22%). The C.5 DT model achieved moderate performance with 83.5% accuracy, 80.5% area under the curve, 71% precision, 86% negative predictive value, 43% sensitivity, 95% specificity and 54% F-score. Out of 24 predictors, C.5 DT identified 5 variables predicting occurrence of VAP post-moderate to severe TBI (Time from injury to emergency department arrival, blood transfusion during resuscitation, comorbidities, Injury Severity Score and pneumothorax).

CONCLUSIONS

This study could serve as baseline for the quest of predicting VAP in patients with TBI through the utilization of C.5. DT machine learning approach. This model helps provide timely decision support to caregivers to improve patient's outcomes.

Prolonged Prehospital Time is a Risk Factor for Pneumonia in Trauma (the PRE-TRIP study): A Retrospective Analysis of the United States National Trauma Data Bank

BACKGROUND

Although multiple risk factors for development of pneumonia in patients with trauma sustained in a motor vehicle accident have been studied, the effect of prehospital time on pneumonia incidence post-trauma is unknown.

RESEARCH QUESTION

Is prolonged prehospital time an independent risk factor for pneumonia?

STUDY DESIGN AND METHODS

We retrospectively analyzed prospectively collected clinical data from 806,012 motor vehicle accident trauma incidents from the roughly 750 trauma hospitals contributing data to the National Trauma Data Bank between 2010 and 2016.

RESULTS

Prehospital time was independently associated with development of pneumonia post-motor vehicle trauma (p < 0.001). This association was primarily driven by patients with low Glasgow Coma Scale scores. Post-trauma pneumonia was uncommon (1.5% incidence) but was associated with a significant increase in mortality (p < 0.001, 4.3% mortality without pneumonia vs. 12.1% mortality with pneumonia). Other pneumonia risk factors included age, sex, race, primary payor, trauma center teaching status, bed size, geographic region, intoxication, comorbid lung disease, steroid use, lower Glasgow Coma Scale score, higher Injury Severity Scale score, blood product transfusion, chest trauma, and respiratory burns.

INTERPRETATION

Increased prehospital time is an independent risk factor for development of pneumonia and increased mortality in patients with trauma caused by a motor vehicle accident. Although prehospital time is often not modifiable, its recognition as a pneumonia risk factor is important as prolonged prehospital time may need to be considered in subsequent decision making.

CLINICAL TRIAL REGISTRATION

Not applicable.

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.

Reinventing the wheel: Impact of prolonged antibiotic exposure on multidrug-resistant ventilator-associated pneumonia in trauma patients

BACKGROUND

Multidrug-resistant (MDR) strains of both Acinetobacter baumannii (AB) and Pseudomonas aeruginosa (PA) as causative ventilator-associated pneumonia (VAP) pathogens are becoming increasingly common. Still, the risk factors associated with this increased resistance have yet to be elucidated. The purpose of this study was to examine the changing sensitivity patterns of these pathogens over time and determine which risk factors predict MDR in trauma patients with VAP.

METHODS

Patients with either AB or PA VAP over 10 years were stratified by pathogen sensitivity (sensitive [SEN] and MDR), age, severity of shock, and injury severity. Prophylactic and empiric antibiotic days, risk factors for severe VAP, and mortality were compared. Multivariable logistic regression was performed to determine which risk factors were independent predictors of MDR.

RESULTS

Three hundred ninety-seven patients were identified with AB or PA VAP. There were 173 episodes of AB (91 SEN and 82 MDR) and 224 episodes of PA (170 SEN and 54 MDR). The incidence of MDR VAP did not change over the study (p = 0.633). Groups were clinically similar with the exception of 24-hour transfusions (14 vs. 19 units, p = 0.009) and extremity Abbreviated Injury Scale (AIS) score (1 vs. 3, p < 0.001), both significantly increased in the MDR group. Antibiotic exposure as well as multiple episodes of inadequate empiric antibiotic therapy (mIEAT) (63% vs. 81%, p < 0.001) were significantly increased in the MDR group. Multivariable logistic regression identified prophylactic antibiotic days (odds ratio, 23.1; 95% confidence interval, 16.7-28, p < 0.001) and mIEAT (odds ratio, 18.1; 95% confidence interval, 12.2-26.1, p = 0.001) as independent predictors of MDR after adjusting for severity of shock, injury severity, severity of VAP, and antibiotic exposure.

CONCLUSION

Prolonged exposure to unnecessary antibiotics remains one of the strongest predictors for the development of antibiotic resistance. Multivariable logistic regression identified prophylactic antibiotic days and mIEAT an independent risk factors for MDR VAP. Thus, limiting prophylactic antibiotic days is the only potentially modifiable risk factor for the development of MDR VAP in trauma patients.

LEVEL OF EVIDENCE

Level IV Therapeutic; level III Prognostic.

Platelet transfusion increases risk for acute respiratory distress syndrome in non-massively transfused blunt trauma patients

PURPOSE

While damage control resuscitation is known to confer a survival advantage in severely injured patients, high-ratio blood component therapy should be initiated only in carefully selected trauma patients, due to the morbidity associated with blood product use. With this project, we aim to identify the effect of platelet transfusion in non-massively transfused bluntly injured patients.

METHODS

The Glue Grant database was retrospectively queried and severely injured blunt trauma patients who underwent non-massive transfusion were identified. Patients were divided into quartiles depending on platelet volume they were transfused in the first 48 h. Outcomes of interest included mortality; ventilator, Intensive Care Unit (ICU) and hospital length of stay (LOS); infectious and non-infectious complications. Multivariable regression models were fitted for these outcomes, controlling for age, pre-existing comorbidities, injury severity, acute physiologic derangement, neurologic injury burden, and other fluid and blood product resuscitation.

RESULTS

There was no difference in mortality, LOS, or the incidence of multi-organ failure and infectious complications. However, patients receiving ≥ 250 mL of platelets were more likely to develop acute respiratory distress syndrome (ARDS) compared to those who received < 250 mL [odds ratio 1.91 (95% CI 1.10-3.33, p = 0.022)].

CONCLUSIONS

Pre-emptive platelet transfusion should be avoided in non-massively transfused blunt injury victims in the absence of true or functional thrombocytopenia, as it increases risk for ARDS with no survival benefit.

Hypothermia indices among severely injured trauma patients undergoing urgent surgery: A single-centred retrospective quality review and analysis

BACKGROUND

Hypothermia (<36°C) exacerbates trauma-induced coagulopathy and worsens morbidity and mortality among severely injured trauma patients; there is a paucity of published data describing how well trauma centres adhere to standards regarding measurement of temperature, and best practices for preventing and treating hypothermia.

METHODS

We completed a retrospective quality audit of all severely injured trauma patients (Injury Severity Score (ISS≥20)) who had urgent surgery at Sunnybrook Health Sciences Centre (SHSC) between 2010 and 2014. Information regarding temperature monitoring was evaluated over the course of the initial resuscitation and admission. Independent risk factors for in-hospital mortality were elucidated through a multivariable regression analysis.

RESULTS

Out of a total of 4492 trauma patients, 495 were severely-injured and went to the operating room (OPR) after being treated in the trauma bay (TB) at SHSC between 2010 and 2014. The majority of the patients were male (n=384, 77.6%) and had a blunt mechanism of injury (n=391, 79.0%). The median ISS score was 29 (interquartile range (IQR) 26, 35). Eighty-nine (17.9%) patients died; 26 (5.2%) of these patients died intra-operatively. Less than one fifth of patients (n=82,16.6%) received a temperature measurement during pre-hospital transport phase. Upon arrival to the TB, almost two-thirds (n=301, 60.8%) of patients had their temperature recorded and a similar proportion (n=175, 58.1%) of those patients were hypothermic (<36°C). In the OPR, close to 80% (n=389, 78.6%) of patients had their temperature measured on both arrival; almost 60% (n=223, 57.3%) were hypothermic on arrival. Almost all patients had their temperature measured upon arrival to the ICU or specialized ward (n=450, 98.3%). Warming initiatives were documented in only 36 (7.3%) patients in the TB, yet documented in almost all patients in OR (n=464, 93.7%). An increased risk of in-hospital mortality was correlated with not taking a temperature measurement in the TB (Odds Ratio (OR) 2.86 (95% Confidence Interval (CI) [1.64-4.99]) or OPR (OR 4.66 (95% CI [2.50-8.69]).

CONCLUSIONS

A majority of severely injured trauma patients are hypothermic well into the perioperative period after initial admission. An absence of having temperature measurement during initial hospitalization is associated with increased in-hospital mortality amongst this patient group. Quality improvement initiatives should aim to strive for ongoing temperature measurement as a key performance indicator and early prevention and treatment of hypothermia during initial resuscitation.

Aged Human Stored Red Blood Cell Supernatant Inhibits Macrophage Phagocytosis in an HMGB1 Dependent Manner After Trauma in a Murine Model

Red blood cell transfusions in the setting of trauma are a double-edged sword, as it is a necessary component for life-sustaining treatment in massive hemorrhagic shock, but also associated with increased risk for nosocomial infections and immune suppression. The mechanisms surrounding this immune suppression are unclear. Using supernatant from human packed red blood cell (RBC), we demonstrate that clearance of Escherichia coli by macrophages is inhibited both in vitro and in vivo using a murine model of trauma and hemorrhagic shock. We further explore the mechanism of this inhibition by demonstrating that human-stored RBCs contain soluble high-mobility group box 1 protein (HMGB1) that increases throughout storage. HMGB1 derived from the supernatant of human-stored RBCs was shown to inhibit bacterial clearance, as neutralizing antibodies to HMGB1 restored the ability of macrophages to clear bacteria. These findings demonstrate that extracellular HMGB1 within stored RBCs could be one factor leading to immune suppression following transfusion in the trauma setting.

Is platelet transfusion associated with hospital-acquired infections in critically ill patients?

BACKGROUND

Platelets are commonly transfused to critically ill patients. Reports suggest an association between platelet transfusion and infection. However, there is no large study to have determined whether platelet transfusion in critically ill patients is associated with hospital-acquired infection.

METHODS

We conducted a multi-centre study using prospectively maintained databases of two large academic intensive care units (ICUs) in Australia. Characteristics of patients who received platelets in ICUs between 2008 and 2014 were compared to those of patients who did not receive platelets. Association between platelet administration and infection (bacteraemia and/or bacteriuria) was modelled using multiple logistic regression and Cox regression, with blood components as time-varying covariates. A propensity covariate adjustment was also performed to verify results.

RESULTS

Of the 18,965 patients included, 2250 (11.9%) received platelets in ICU with a median number of 1 platelet unit (IQR 1-3) administered. Patients who received platelets were more severely ill at ICU admission (mean Acute Physiology and Chronic Health Evaluation III score 65 (SD 29) vs 52 (SD 25), p < 0.01) and had more comorbidities (31% vs 19%, p < 0.01) than patients without platelet transfusion. Invasive mechanical ventilation (87% vs 57%, p < 0.01) and renal replacement therapy (20% vs 4%, p < 0.01) were more frequently administered in patients receiving platelets than in patients without platelets. On univariate analysis, platelet transfusion was associated with hospital-acquired infection in the ICU (7.7% vs 1.4%, p < 0.01). After adjusting for confounders, including other blood components administered, patient severity, centre, year, and diagnosis category, platelet transfusions were independently associated with infection (adjusted OR 2.56 95% CI 1.98-3.31, p < 0.001). This association was also found in survival analysis with blood components as time-varying covariates (adjusted HR 1.85, 95% CI 1.41-2.41, p < 0.001) and when only bacteraemia was considered (adjusted OR 3.30, 95% CI 2.30-4.74, p <0.001). Platelet transfusions remained associated with infection after propensity covariate adjustment.

CONCLUSIONS

After adjustment for confounders, including patient severity and other blood components, platelet transfusion was independently associated with ICU-acquired infection. Further research aiming to better understand this association and to prevent this complication is warranted.

Transfusion-related immunomodulation: review of the literature and implications for pediatric critical illness

Transfusion-related immunomodulation (TRIM) in the intensive care unit (ICU) is difficult to define and likely represents a complicated set of physiologic responses to transfusion, including both proinflammatory and immunosuppressive effects. Similarly, the immunologic response to critical illness in both adults and children is highly complex and is characterized by both acute inflammation and acquired immune suppression. How transfusion may contribute to or perpetuate these phenotypes in the ICU is poorly understood, despite the fact that transfusion is common in critically ill patients. Both hyperinflammation and severe immune suppression are associated with poor outcomes from critical illness, underscoring the need to understand potential immunologic consequences of blood product transfusion. In this review we outline the dynamic immunologic response to critical illness, provide clinical evidence in support of immunomodulatory effects of blood product transfusion, review preclinical and translational studies to date of TRIM, and provide insight into future research directions.

Protocols for massive blood transfusion: when and why, and potential complications

PURPOSE

An update paper on massive bleeding after major trauma. A review of protocols to address massive bleeding, and its possible complications, including coagulation abnormalities, complications related to blood storage, immunosuppression and infection, lung injury associated with transfusion, and hypothermia is carried out.

METHODS

Literature review and discussion with authors' experience.

RESULTS

Massive bleeding is an acute life-threatening complication of major trauma, and consequently its prompt diagnosis and treatment is of overwhelming importance. Treatment requires rapid surgical management together with the massive infusion of colloid and blood.

CONCLUSIONS

Since massive transfusion provokes further problems in patients who are already severely traumatized and anaemic, once this course of action has been decided upon, a profound knowledge of its potential complications, careful monitoring and proper follow-up are all essential. To diagnose this bleeding, most authors favour, as the main first choice tool, a full-body CT scan (head to pelvis), in non-critical severe trauma cases. In addition, focused abdominal sonography for trauma (FAST, an acronym that highlights the necessity of rapid performance) is a very important diagnostic test for abdominal and thoracic bleeding. Furthermore, urgent surgical intervention should be undertaken for patients with significant free intraabdominal fluid and haemodynamic instability. Although the clinical situation and the blood haemoglobin concentration are the key factors considered in this rapid decision-making context, laboratory markers should not be based on a single haematocrit value, as its sensitivity to significant bleeding may be very low. Serum lactate and base deficit are very sensitive markers for detecting and monitoring the extent of bleeding and shock, in conjunction with repeated combined measurements of prothrombin time, activated partial thromboplastin time, fibrinogen and platelets.

Innate immune function predicts the development of nosocomial infection in critically injured children

BACKGROUND

Critical injury has been associated with reduction in innate immune function in adults, with infection risk being related to degree of immune suppression. This relationship has not been reported in critically injured children.

HYPOTHESIS

Innate immune function will be reduced in critically injured children, and the degree of reduction will predict the subsequent development of nosocomial infection.

METHODS

Children (≤18 years old) were enrolled in this longitudinal, prospective, observational, single-center study after admission to the pediatric intensive care unit following critical injury, along with a cohort of outpatient controls. Serial blood sampling was performed to evaluate plasma cytokine levels and innate immune function as measured by ex vivo lipopolysaccharide-induced tumor necrosis factor α (TNF-α) production capacity.

RESULTS

Seventy-six critically injured children (and 21 outpatient controls) were enrolled. Sixteen critically injured subjects developed nosocomial infection. Those subjects had higher plasma interleukin 6 and interleukin 10 levels on posttrauma days 1-2 compared with those who recovered without infection and outpatient controls. Ex vivo lipopolysaccharide-induced TNF-α production capacity was lower on posttrauma days 1-2 (P = 0.006) and over the first week following injury (P = 0.04) in those who went on to develop infection. A TNF-α response of less than 520 pg/mL at any time in the first week after injury was highly associated with infection risk by univariate and multivariate analysis. Among transfused children, longer red blood cell storage age, not transfusion volume, was associated with lower innate immune function (P < 0.0001). Trauma-induced innate immune suppression was reversible ex vivo via coculture of whole blood with granulocyte-macrophage colony-stimulating factor.

CONCLUSIONS

Trauma-induced innate immune suppression is common in critically injured children and is associated with increased risks for the development of nosocomial infection. Potential exacerbating factors, including red blood cell transfusion, and potential therapies for pediatric trauma-induced innate immune suppression are deserving of further study.

A multicenter, randomized clinical trial of IV iron supplementation for anemia of traumatic critical illness*

OBJECTIVE

To evaluate the efficacy of IV iron supplementation of anemic, critically ill trauma patients.

DESIGN

Multicenter, randomized, single-blind, placebo-controlled trial.

SETTING

Four trauma ICUs.

PATIENTS

Anemic (hemoglobin < 12 g/dL) trauma patients enrolled within 72 hours of ICU admission and with an expected ICU length of stay of more than or equal to 5 days.

INTERVENTIONS

Randomization to iron sucrose 100 mg IV or placebo thrice weekly for up to 2 weeks.

MEASUREMENTS AND MAIN RESULTS

A total of 150 patients were enrolled. Baseline iron markers were consistent with functional iron deficiency: 134 patients (89.3%) were hypoferremic, 51 (34.0%) were hyperferritinemic, and 64 (42.7%) demonstrated iron-deficient erythropoiesis as evidenced by an elevated erythrocyte zinc protoporphyrin concentration. The median baseline transferrin saturation was 8% (range, 2-58%). In the subgroup of patients who received all six doses of study drug (n = 57), the serum ferritin concentration increased significantly for the iron as compared with placebo group on both day 7 (808.0 ng/mL vs 457.0 ng/mL, respectively, p < 0.01) and day 14 (1,046.0 ng/mL vs 551.5 ng/mL, respectively, p < 0.01). There was no significant difference between groups in transferrin saturation, erythrocyte zinc protoporphyrin concentration, hemoglobin concentration, or packed RBC transfusion requirement. There was no significant difference between groups in the risk of infection, length of stay, or mortality.

CONCLUSIONS

Iron supplementation increased the serum ferritin concentration significantly, but it had no discernible effect on transferrin saturation, iron-deficient erythropoiesis, hemoglobin concentration, or packed RBC transfusion requirement. Based on these data, routine IV iron supplementation of anemic, critically ill trauma patients cannot be recommended (NCT 01180894).

Increased trauma center volume is associated with improved survival after severe injury: results of a Resuscitation Outcomes Consortium study

OBJECTIVE

To investigate the relationship between trauma center volume and outcome.

BACKGROUND

The Resuscitation Outcomes Consortium is a network of 11 centers and 60 hospitals conducting emergency care research. For many procedures, high-volume centers demonstrate superior outcomes versus low-volume centers. This remains controversial for trauma center outcomes.

METHODS

This study was a secondary analysis of prospectively collected data from the Resuscitation Outcomes Consortium multicenter out-of-hospital Hypertonic Saline Trial in patients with Glasgow Coma Scale score of 8 or less (traumatic brain injury) or systolic blood pressure of 90 or less and pulse of 110 or more (shock). Regression analyses evaluated associations between trauma volume and the following outcomes: 24-hour mortality, 28-day mortality, ventilator-free days, Multiple Organ Dysfunction Scale incidence, worst Multiple Organ Dysfunction Scale score, and poor 6-month Glasgow Outcome Scale-Extended score.

RESULTS

A total of 2070 patients were evaluated: 1251 in the traumatic brain injury cohort and 819 in the shock cohort. Overall, 24-hour and 28-day mortality was 16% and 25%, respectively. For every increase of 500 trauma center admissions, there was a 7% decreased odds of 24-hour and 28-day mortality for all patients. As trauma center volume increased, nonorgan dysfunction complications increased, ventilator-free days increased, and worst Multiple Organ Dysfunction Scale score decreased. The associations with higher trauma center volume were similar for the traumatic brain injury cohort, including better neurologic outcomes at 6 months, but not for the shock cohort.

CONCLUSIONS

Increased trauma center volume was associated with increased survival, more ventilator-free days, and less severe organ failure. Trauma system planning and implementation should avoid unnecessary duplication of services.

Transfusion of fresh-frozen plasma in critically ill patients with a coagulopathy before invasive procedures: a randomized clinical trial (CME)

BACKGROUND

Prophylactic use of fresh-frozen plasma (FFP) is common practice in patients with a coagulopathy undergoing an invasive procedure. Evidence that FFP prevents bleeding is lacking, while risks of transfusion-related morbidity after FFP have been well demonstrated. We aimed to assess whether omitting prophylactic FFP transfusion in nonbleeding critically ill patients with a coagulopathy who undergo an intervention is noninferior to a prophylactic transfusion of FFP.

STUDY DESIGN AND METHODS

A multicenter randomized open-label trial with blinded endpoint evaluation was performed in critically ill patients with a prolonged international normalized ratio (INR; 1.5-3.0). Patients undergoing placement of a central venous catheter, percutaneous tracheostomy, chest tube, or abscess drainage were eligible. Patients with clinically overt bleeding, thrombocytopenia, or therapeutic use of anticoagulants were excluded. Patients were randomly assigned to omitting or administering a prophylactic transfusion of FFP (12 mL/kg). Outcomes were occurrence of postprocedural bleeding complications, INR correction, and occurrence of lung injury.

RESULTS

Due to slow inclusion, the trial was stopped before the predefined target enrollment was reached. Eighty-one patients were randomly assigned, 40 to FFP and 41 to no FFP transfusion. Incidence of bleeding did not differ between groups, with a total of one major and 13 minor bleedings (p = 0.08 for noninferiority). FFP transfusion resulted in a reduction of INR to less than 1.5 in 54% of transfused patients. No differences in lung injury scores were observed.

CONCLUSION

In critically ill patients undergoing an invasive procedure, no difference in bleeding complications was found regardless whether FFP was prophylactically administered or not.

The burden of infection in severely injured trauma patients and the relationship with admission shock severity

BACKGROUND

Infection following severe injury is common and has a major impact on patient outcomes. The relationship between patient, injury, and physiologic characteristics with subsequent infections is not clearly defined. The objective of this study was to characterize the drivers and burden of all-cause infection in critical care trauma patients.

METHODS

A prospective cohort study of severely injured adult patients admitted to critical care was conducted. Data were collected prospectively on patient and injury characteristics, baseline physiology, coagulation profiles, and blood product use. Patients were followed up daily for infectious episodes and other adverse outcomes while in the hospital.

RESULTS

Three hundred patients (Injury Severity Score [ISS] >15) were recruited. In 48 hours or less, 29 patients (10%) died, leaving a cohort of 271. One hundred forty-one patients (52%) developed at least one infection. Three hundred four infections were diagnosed overall. Infection and noninfection groups were matched for age, sex, mechanism, and ISS. Infection rates were greater with any degree of admission shock and threefold higher in the most severely shocked cohort (p < 0.01). In multivariate analysis, base deficit (odds ratio [OR], 1.78, 95% confidence interval [CI], 1.48-1.94; p < 0.001) and lactate (OR, 1.36; 95% CI, 1.10-1.69; p = 0.05) were independently associated with the development of infection. Outcomes were significantly worse for the patients with infection. In multivariate logistic regression, infection was the only factor independently associated with multiple-organ failure (p < 0.001; OR, 15.4; 95% CI, 8.2-28.9; r = 0.402), ventilator-free days (p < 0.001; β, -4.48; 95% CI, -6.7 to -2.1; r = 0.245), critical care length of stay (p < 0.001; β, 13.2; 95% CI, 10.0-16.4; r = 0.466), and hospital length of stay (p < 0.001; β, 31.1; 95% CI, 24.0-38.2; r = 0.492).

CONCLUSION

Infectious complications are a burden for severely injured patients and occur early in the critical care stay. Severity of admission shock was predictive of infection and represents an opportunity for interventions to improve infectious outcomes. The incidence of infection may also have utility as an end point for clinical trials in trauma hemorrhage given the relationship with patient-experienced outcomes.

LEVEL OF EVIDENCE

Prognostic/epidemiologic study, level II.

Independent risk factors for ventilator-associated pneumonia after cardiac surgery

OBJECTIVE

To investigate the related factors and pathogens of ventilator-associated pneumonia (VAP) after heart surgery so as to provide evidences for clinical prevention and therapy.

METHODS

In total 1,688 cases were collected from January 2004 to January 2011. Overall 105 patients developed VAP. Retrospectively analyzed these patients after heart surgery to determine the clinical data, pathogens and treatment measures.

RESULTS

The frequency of ventilator-associated pneumonia was 6.2% (105/1 688), and mortality was 25.7% (27/105), 198 pathogen strains were isolated by bacterial culture, in which Gram negative bacteria accounted for 69.2% (137/198), Gram positive bacteria 27.8% (55/198), and fungi 3.0% (6/198). The independent risk factors for VAP after cardiac surgery were: age >70 (p < .01), emergent surgery (p < .01), perioperative blood transfusions (p < 0.01), reintubation (p < .01) and days of mechanical ventilation (MV) (p < .01). Median length of stay in the ICU for patients who developed VAP or not was, respectively, (24.7 ± 4.5) days versus (3.2 ± 1.5) days (p < .05), and mortality was, respectively, 25.7% versus 2.9% in both populations (p < .05).

CONCLUSION

Age >70, emergent surgery, perioperative blood transfusions, reintubation and days of MV are the risk factors for VAP in patients following cardiac surgery. P. aeruginosa, P. klebsiella, S. aureus, and Acinetobacter baumannii were the main pathogens of VAP. According to the cause of VAP, active prevention and treatment measures should be developed and applied to shorten the time of MV and improve chances of survival.

[Costs of delivering allogenic blood in hospitals]

INTRODUCTION

In clinical practice there are medical and economic reasons against the thoughtless use of packed red blood cells (rbc). Therefore, in searching for alternatives (therapy of anemia) the total costs of allogeneic blood transfusions must be considered. Using a practical example this article depicts the actual costs and possible alternatives from the point of view of a hospital in Germany.

METHOD

To determine the total costs of allogeneic blood transfusions the actual resource consumption associated with blood transfusions was collated and analyzed at the St. Marien-Hospital in Vechta.

RESULTS

The authors were able to show that the actual procurement costs (average. 97 EUR) represent only 55  % of the total costs of 176 EUR. The additional expenses are allocated to personnel (78  %) and materials (22  %). Alternatives, such as i.v. iron substitution or stimulation of erythropoesis might be the more economical solution especially if only purchase prices are compared and the total costs of allogeneic blood transfusions are not considered.

DISCUSSION

Analyzing a single hospital limits generalization of the results; however, in the international context the results can be recognized as plausible. So far there have been no comprehensive studies on the true costs of blood preparations, therefore, this article represents a first starting point for closing this gap by conducting additional studies.

Assessment of hemoglobin threshold for packed RBC transfusion in a medical-surgical PICU

OBJECTIVE

Results of a large multicenter randomized clinical trial published in 2007 demonstrated no benefit in using a liberal versus conservative RBC transfusion threshold in stable critically ill children. Using the conservative threshold decreased the number of RBC transfusions without increasing adverse outcomes. We aimed to determine if wide dissemination of this evidence altered the hemoglobin threshold used for RBC transfusions in our pediatric medical-surgical ICU.

DESIGN

Before-after retrospective cohort study using multiple administrative databases and chart review.

SETTING

PICU serving medical and surgical patients.

PATIENTS

All potentially stable children receiving a RBC transfusion in the PICU in 2006 (prepublication) and in 2009-2010 (postpublication). Children were considered unstable and excluded if they were severely hypoxic, receiving renal replacement therapy, hemodynamically unstable, or bleeding.

INTERVENTIONS

Physician education on evidence supporting hemoglobin transfusion thresholds in teaching conferences, staff meetings, and via e-mail.

MEASUREMENTS AND MAIN RESULTS

In 2006, 14.6% of patients (n = 285/1,940) received a RBC transfusion. In 2009-2010, 12.1% of patients (n = 551/4,542) received a RBC transfusion. We evaluated patients transfused when they were potentially clinically stable, including 145 children in 2006 (191 transfusion days) and 266 children in 2009-2010 (369 transfusion days). We found no significant differences in age, sex, race, diagnoses, postoperative status, illness severity scores, mortality, or length of stay between these two groups. The median hemoglobin transfusion threshold decreased significantly from 8.0 g/dL (interquartile range 7.3, 8.6 g/dL) in 2006 to 7.5 g/dL (interquartile range 6.9, 8.1 g/dL) in 2009-2010 (p = 0.001). The percentage of transfusion days using a hemoglobin threshold more than 7 g/dL decreased from 81% (n = 154) in 2006 to 71% (n = 261) in 2009-2010.

CONCLUSION

Although transfusion thresholds in potentially stable critically ill children in our PICU significantly decreased after dissemination of best available evidence, 71% of patients were transfused at a hemoglobin threshold more than 7 g/dL.

Diabetes and hemoglobin a1c as risk factors for nosocomial infections in critically ill patients

Objective. To evaluate whether diabetes mellitus (DM) and hemoglobin A1c (HbA1c) are risk factors for ventilator-associated pneumonia (VAP) and bloodstream infections (BSI) in critically ill patients. Methods. Prospective observational study; patients were recruited from the intensive care unit (ICU) of a general district hospital between 2010 and 2012.

INCLUSION CRITERIA

ICU hospitalization >72 hours and mechanical ventilation >48 hours. HbA1c was calculated for all participants. DM, HbA1c, and other clinical and laboratory parameters were assessed as risk factors for VAP or BSI in ICU. Results. The overall ICU incidence of VAP and BSI was 26% and 30%, respectively. Enteral feeding OR (95%CI) 6.20 (1.91-20.17; P = 0.002) and blood transfusion 3.33 (1.23-9.02; P = 0.018) were independent risk factors for VAP. BSI in ICU (P = 0.044) and ICU mortality (P = 0.038) were significantly increased in diabetics. Independent risk factors for BSI in ICU included BSI on admission 2.45 (1.14-5.29; P = 0.022) and stroke on admission2.77 (1.12-6.88; P = 0.029). Sepsis 3.34 (1.47-7.58; P = 0.004) and parenteral feeding 6.29 (1.59-24.83; P = 0.009) were independently associated with ICU mortality. HbA1c ≥ 8.1% presented a significant diagnostic performance in diagnosing repeated BSI in ICU. Conclusion. DM and HbA1c were not associated with increased VAP or BSI frequency. HbA1c was associated with repeated BSI episodes in the ICU.

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.

The acute immunological response to blood transfusion is influenced by polymicrobial sepsis

Blood transfusion is a well-established risk factor for adverse outcomes during sepsis. The specific mechanisms responsible for this effect remain elusive, and few studies have investigated this phenomenon in a model that reflects not only the clinical circumstances in which blood is transfused, but also how packed red blood cells (PRBCs) are created and stored. Using a cecal ligation and puncture model of polymicrobial sepsis as well as creating murine allogeneic and stored PRBCs in a manner that replicates the clinical process, we have demonstrated that transfusion of PRBCs induces numerous effects on leukocyte subpopulations. In polymicrobial sepsis, these responses are profoundly dissimilar to the proinflammatory effects of PRBC transfusion observed in the healthy mouse. Transfused septic mice, as opposed to mice receiving crystalloid resuscitation, had a significant loss of blood, spleen, and bone marrow lymphocytes, especially those with an activated phenotype. Myeloid cells behaved similarly, although they were able to produce more reactive oxygen species. Overall, transfusion in the septic mouse may contribute to the persistent immune dysfunction known to be associated with this process, rather than simply promote proinflammatory or anti-inflammatory effects on the host. Thus, it is possible that blood transfusion contributes to the multiple known effects of sepsis on leukocyte populations that have been shown to result in increased morbidity and mortality.

Early death and late morbidity after blood transfusion of injured children: a pilot study

BACKGROUND/PURPOSE

Early postinjury death after packed red blood cell (pRBC) transfusion is attributed to uncontrolled hemorrhage and coagulopathy. The adverse immunomodulatory effects of blood transfusion are implicated in subsequent morbidity. We hypothesized that injured children requiring pRBC transfusion demonstrate patterns in outcome similar to those observed in adults.

METHODS

Our prospectively collected trauma registry was queried for demographics, treatment, and outcome (2006-2009). Outcomes of children who received pRBC transfusion were compared with those of age- and Injury Severity Score (ISS)-matched children who did not receive pRBC transfusion by both univariate and multivariable analysis.

RESULTS

Eight percent (43/512) of injured children received a pRBC transfusion: 20 early and 23 late. The likelihood of pRBC transfusion increased with increasing ISS (ISS <15, 2%; ISS 16-25, 17%; ISS >25, 72%). One-half of injured children who received an early pRBC transfusion died; however, most deaths were because of central nervous system injury. Both ventilator and intensive care unit days were increased in children who received pRBC transfusion as compared with those who did not.

CONCLUSION

Early pRBC transfusion is associated with a high mortality in children. Late blood transfusion is associated with worse outcomes, although this relationship may not be causal. This pilot study provides evidence of an association between pRBC transfusion, morbidity, and mortality among injured children that warrants refinement in larger, prospective investigations.

Exploring the influence of enforcing infection control directives on the risk of developing healthcare associated infections in the intensive care unit: a retrospective study

Background

Although strict adherence to infection control strategies is recognised as the simplest and most cost effective method to prevent the spread of healthcare associated infections (HAIs), measurement of the direct impact that such adherence may have on the risk of developing such infections has always been a challenge.

Purpose

The purpose of this study was to compare the risk of HAIs before and during the SARS outbreak. Such comparison is intended to provide a surrogate measure of the influence that strict enforcement of infection control strategies during the SARS outbreak may have had on the risk of HAIs.

Methods

A retrospective chart review was conducted on the medical records of 400 intensive care patients who were admitted to the ICU three months before and during the 2003 SARS outbreak.

Results

The rate of HAIs was higher in the pre-SARS period than the SARS period. Specifically, 61.7% of all reported infections were diagnosed in the pre-SARS period. The rate of HAIs in the pre-SARS period was 14.5% as opposed to 9% during the SARS period. Adjusted logistic regression analysis suggested that the odds of HAIs were 2.2 times higher in the pre-SARS period as compared to the SARS period (OR = 2.2; 95%CI = 1.08–4.49).

Conclusion

Our findings suggest that strict enforcement of infection control strategies may have a positive impact on the efforts to minimise the risk of HAIs. These findings carry a clinical significance that shall not be ignored with regard to our overall efforts to minimise the risk of developing HAIs in the ICU.

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.

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.

Use of airway pressure release ventilation is associated with a reduced incidence of ventilator-associated pneumonia in patients with pulmonary contusion

BACKGROUND

Past studies suggest that airway pressure release ventilation (APRV) is associated with reduced sedative requirements and increased recruitment of atelectatic lung, two factors that might reduce the risk for ventilator-associated pneumonia (VAP). We investigated whether APRV might be associated with a decreased risk for VAP in patients with pulmonary contusion.

MATERIALS

Retrospective cohort study.

RESULTS

Of 286, 64 (22%) patients requiring mechanical ventilation for >48 hours met criteria for pulmonary contusion and were the basis for this study. Subjects with pulmonary contusion had a significantly higher rate of VAP than other trauma patients, [VAP rate contusion patients: 18.3/1,000, non-contusion patients: 7.7/1,000, incidence rate ratio 2.37 (95% confidence interval [CI], 1.11-4.97), p=0.025]. Univariate analysis showed that APRV (hazard ratio, 0.15 [0.03-0.72; p=0.018]) was associated with a decreased incidence of VAP. Cox proportional hazards regression, using propensity scores for APRV to control for confounding, supported a protective effect of APRV from VAP (hazard ratio, 0.10 [95% CI, 0.02-0.58]; p=0.01). Pao2/FiO2 ratios were higher during APRV compared with conventional ventilation (p<0.001). Subjects attained the goal Sedation Agitation Score for an increased percentage of time during APRV (median [interquartile range (IQR)] 72.7% [33-100] of the time) compared with conventional ventilation (47.2% [0-100], p=0.044), however, dose of sedatives was not different between these subjects. APRV was not associated with hospital mortality (odds ratio 0.57 [95% CI, 0.06-5.5]; p=0.63) or ventilator-free days (No APRV 15.4 vs. APRV 13.7 days, p=0.49).

CONCLUSION

Use of APRV in patients with pulmonary contusion is associated with a reduced risk for VAP.

Relationship between inhaled β₂-agonists and ventilator-associated pneumonia: a cohort study

OBJECTIVE

To determine the impact of aerosolized bronchodilators on ventilator-associated pneumonia.

DESIGN

Prospective cohort study.

SETTING

A 30-bed medical and surgical intensive care unit.

METHODS

All intubated patients requiring mechanical ventilation for >48 hrs were eligible during a 13-month period. Nebulized β2-agonists were administered at the intensive care unit physician's discretion. Ventilator-associated pneumonia definition included clinical and quantitative microbiological criteria. Only first ventilator-associated pneumonia episodes were analyzed. Risk factors for ventilator-associated pneumonia were determined using univariate and multivariate analyses. The influence of inhaled β2-agonists on ventilator-associated pneumonia occurrence was also adjusted for confounding factors using Cox's proportional-hazards model.

RESULTS

Ventilator-associated pneumonia was diagnosed in 137 (31%) of the 439 enrolled patients. Ventilator-associated pneumonia was early-onset in 14 (10%) patients. The incidence rate of ventilator-associated pneumonia was 20 per 1,000 ventilator days. Ventilator-associated pneumonia was polymicrobial in 16 (11%) patients, and related to multidrug-resistant bacteria in 42 (28%) patients. Most cases of ventilator-associated pneumonia were caused by Gram-negative bacteria. Inhaled β2-agonists were significantly more frequently used in patients with ventilator-associated pneumonia compared with those without ventilator-associated pneumonia (49% vs. 34%, odds ratio [95% confidence interval] = 1.9 [1.2-2.8], p = .003). Multivariate analysis identified aerosolized β2-agonists (odds ratio [95% confidence interval] = 1.7 [1.1-2.6], p = .012), Simplified Acute Physiology Score II at intensive care unit admission (odds ratio [95% confidence interval] = 1.01 [1.001-1.02] per point, p = .031), and red blood cell transfusion (odds ratio [95% confidence interval] = 2 [1.3-3.1], p = .001) as independent risk factors for ventilator-associated pneumonia. Cox's proportional-hazards model also identified inhaled β2-agonists as a risk factor for ventilator-associated pneumonia (odds ratio [95% confidence interval] = 1.52 [1.06-2.19], p = .021).

CONCLUSION

Use of aerosolized bronchodilators in intensive care unit mechanically ventilated patients is an independent risk factor for ventilator-associated pneumonia.

Prophylactic antibiotic days as a predictor of sensitivity patterns in Acinetobacter pneumonia

BACKGROUND

Ventilator-associated pneumonia (VAP) secondary to Acinetobacter spp. in critically ill trauma patients has increased. More importantly, the incidence of multi-drug-resistant (MDR) Acinetobacter VAP has increased. The risk factors for this increase in resistance have yet to be elucidated. The purpose of this study was to evaluate the change in Acinetobacter sensitivity over time and determine which risk factors predict resistance in trauma patients.

METHODS

Patients surviving >5 days post-injury who had Acinetobacter VAP (≥10(5) colony-forming units/mL in bronchoalveolar lavage fluid) who were seen over five years were divided according to pathogen sensitivity (sensitive [SEN] vs. MDR) and stratified by age, severity of shock (base excess, number of blood transfusions), injury severity (Injury Severity Score [ISS], admission Glasgow Coma Scale [GCS] score, chest and extremity Abbreviated Injury Scale score [AIS]), and year. Prophylactic (Pro), empiric (Emp), Pro + Emp, and total antibiotic days, ventilator days, and mortality rate were compared. Multivariable logistic regression (MLR) was performed to determine which risk factors were independent predictors of resistance.

RESULTS

Ninety-six patients (81% male) were identified: 62 SEN and 34 MDR. The groups were clinically similar in terms of age, extent of shock, and injury severity with the exception of extremity AIS. Antibiotic exposure was greater in the MDR group. Over the period of the study, the incidence of MDR Acinetobacter VAP increased from zero to 66% (p < 0.0001). Multiple logistic regression identified Pro antibiotic days as an independent predictor of MDR after adjusting for age and chest AIS (p < 0.0001).

CONCLUSIONS

The incidence of MDR Acinetobacter VAP has increased over time. More severe extremity injuries, as measured by the AIS, may contribute to prolonged antibiotic exposure in those patients with MDR Acinetobacter VAP. Multiple logistic regression identified Pro antibiotic days as an independent risk factor for MDR Acinetobacter VAP in trauma patients.

Impact of plasma transfusion in trauma patients who do not require massive transfusion

BACKGROUND

For trauma patients requiring massive blood transfusion, aggressive plasma usage has been demonstrated to confer a survival advantage. The aim of this study was to evaluate the impact of plasma administration in nonmassively transfused patients.

STUDY DESIGN

Trauma patients admitted to a Level I trauma center (2000-2005) requiring a nonmassive transfusion (<10 U packed RBC [PRBC] within 12 hours of admission) were identified retrospectively. Propensity scores were calculated to match and compare patients receiving plasma in the first 12 hours with those who did not.

RESULTS

The 1,716 patients (86.1% of 1,933 who received PRBC transfusion) received a nonmassive transfusion. After exclusion of 31 (1.8%) early deaths, 284 patients receiving plasma were matched to patients who did not. There was no improvement in survival with plasma transfusion (17.3% versus 14.1%; p = 0.30) irrespective of the plasma-to-PRBC ratio achieved. However, the overall complication rate was significantly higher for patients receiving plasma (26.8% versus 18.3%, odds ratio [OR] = 1.7; 95% CI, 1.1-2.4; p = 0.016). As the volume of plasma increased, an increase in complications was seen, reaching 37.5% for patients receiving >6 U. The ARDS rate specifically was also significantly higher in patients receiving plasma (9.9% versus 3.5%, OR = 3.0; 95% CI, 1.4-6.2; p = 0.004]. Patients receiving >6 U plasma had a 12-fold increase in ARDS, a 6-fold increase in multiple organ dysfunction syndrome, and a 4-fold increase in pneumonia and sepsis.

CONCLUSIONS

For nonmassively transfused trauma patients, plasma administration was associated with a substantial increase in complications, in particular ARDS, with no improvement in survival. An increase in multiple organ dysfunction, pneumonia, and sepsis was likewise seen as increasing volumes of plasma were transfused. The optimal trigger for initiation of a protocol for aggressive plasma infusion warrants prospective evaluation.

Complications of massive transfusion

Massive transfusion (MT) is a lifesaving treatment of hemorrhagic shock, but can be associated with significant complications. The lethal triad of acidosis, hypothermia, and coagulopathy associated with MT is associated with a high mortality rate. Other complications include hypothermia, acid/base derangements, electrolyte abnormalities (hypocalcemia, hypomagnesemia, hypokalemia, hyperkalemia), citrate toxicity, and transfusion-associated acute lung injury. Blood transfusion in trauma, surgery, and critical care has been identified as an independent predictor of multiple organ failure, systemic inflammatory response syndrome, increased infection, and increased mortality in multiple studies. Once definitive control of hemorrhage has been established, a restrictive approach to blood transfusion should be implemented to minimize further complications.

Hospital variation in transfusion and infection after cardiac surgery: a cohort study

BACKGROUND

Transfusion practices in hospitalised patients are being re-evaluated, in part due to studies indicating adverse effects in patients receiving large quantities of stored blood. Concomitant with this re-examination have been reports showing variability in the use of specific blood components. This investigation was designed to assess hospital variation in blood use and outcomes in cardiac surgery patients.

METHODS

We evaluated outcomes in 24,789 Medicare beneficiaries in the state of Michigan, USA who received coronary artery bypass graft surgery from 2003 to 2006. Using a cohort design, patients were followed from hospital admission to assess transfusions, in-hospital infection and mortality, as well as hospital readmission and mortality 30 days after discharge. Multilevel mixed-effects logistic regression was used to calculate the intrahospital correlation coefficient (for 40 hospitals) and compare outcomes by transfusion status.

RESULTS

Overall, 30% (95 CI, 20% to 42%) of the variance in transfusion practices was attributable to hospital site. Allogeneic blood use by hospital ranged from 72.5% to 100% in women and 49.7% to 100% in men. Allogeneic, but not autologous, blood transfusion increased the odds of in-hospital infection 2.0-fold (95% CI 1.6 to 2.5), in-hospital mortality 4.7-fold (95% CI 2.4 to 9.2), 30-day readmission 1.4-fold (95% CI 1.2 to 1.6), and 30-day mortality 2.9-fold (95% CI 1.4 to 6.0) in elective surgeries. Allogeneic transfusion was associated with infections of the genitourinary system, respiratory tract, bloodstream, digestive tract and skin, as well as infection with Clostridium difficile. For each 1% increase in hospital transfusion rates, there was a 0.13% increase in predicted infection rates.

CONCLUSION

Allogeneic blood transfusion was associated with an increased risk of infection at multiple sites, suggesting a system-wide immune response. Hospital variation in transfusion practices after coronary artery bypass grafting was considerable, indicating that quality efforts may be able to influence practice and improve outcomes.