Hypoalbuminemia: incidence and its impact on acute respiratory distress syndrome and 28-day outcome in trauma patients

OBJECTIVE

This prospective observational study explored the effect of early onset hypoalbuminemia (EOH) on the development of adult respiratory distress syndrome (ARDS) in orthopedic trauma victims.

METHODS

Serum albumin levels were measured for the initial 7 days of injury for adult trauma patients (18-65 years). Patients were recruited into group A (any serum albumin value < 3.5 mg/dl) and group B (all serum albumin ≥ 3.5 mg/dl), based on serum albumin values. Patients were followed for the development of ARDS and outcome until 28 days. The primary outcome of the study was to explore the effects of EOH on ARDS.

RESULTS

EOH (any serum albumin value < 3.5 g/dl within 7 days of injury) was present in 205/386 (53.1%) patients. The majority of 174/205 (84.9%) patients had EOH by the fourth day after the injury, with the mean time for development of EOH being 2.15 ± 1.87 days. ARDS manifested in 87/205 (42.4%) and 15/181 (8.3%) patients in group A and group B, respectively (p < 0.001). EOH had 8.2 times greater odds of ARDS (OD 8.2 95% CL 4.7-14.0, p = 0.000). The mean time for the onset of ARDS was 5.63 ± 2.62 days. No statistically significant causal relationship occurred between the onset of EOH and the development of ARDS (Pearson's correlation coefficient = 0.14, p = 0.16). At serum albumin cutoff concentrations of 3.4 gm/dl on D1 (AUC 0.68, 95% CI: 0.61-0.74, p = 0.000), ARDS may be anticipated in 62.8% of patients. The commencement of ARDS was independently correlated with EOH (p = 0.000), Respiratory rate on admission (p = 0.000), inotrope use (p = 0.000), and soft tissue injury (p = 0.000) (R2 = 0.466). The odds of 28-day all-cause death were 7.7 times higher in EOH (OD 7.7 95% CL 3.5-16.7, p = 0.00) and 9 times higher in ARDS (OD 9 95% CL 4.9-16.16, p = 0.00).

CONCLUSION

EOH is a frequent occurrence and has a strong influence development of ARDS and 28-day mortality in trauma patients.

Outcomes of Extracorporeal Membrane Oxygenation in Acute Respiratory Distress Syndrome Following Traumatic Injury: A Propensity-Matched Analysis

Supplemental Digital Content is available in the text.

OBJECTIVES:

The purpose of this study is to evaluate the overall occurrence of inhospital mortality in trauma patients who were placed on extracorporeal membrane oxygenation following the complication of the acute respiratory distress syndrome.

DESIGN:

Observational cohort study.

SETTING:

The data of all patients who were traumatically injured and developed the complication of acute respiratory distress syndrome were accessed from the Trauma Quality Improvement Program database from the calendar years of 2013 to 2016.

PATIENTS:

Patients 16 years old and less than 90 years old were included in the study. Variables included patient demography, Injury Severity Score, Glasgow Coma Scale score, Abbreviated Injury Scale score, and outcomes.

INTERVENTIONS:

Extracorporeal membrane oxygenation.

MEASUREMENTS AND MAIN RESULTS:

Propensity-matched analysis was performed between two groups: patients placed on extracorporeal membrane oxygenation and patients placed on conventional mode of ventilation. The primary outcome was inhospital mortality. Out of 6,121 patients who developed acute respiratory distress syndrome, 118 patients (1.93%) were placed on extracorporeal membrane oxygenation. The pair matched analysis showed significant difference between the two groups (extracorporeal membrane oxygenation vs conventional mode of ventilation) for overall inhospital mortality (35.6% vs 14.4%; p < 0.001). There were significant differences found between the two groups for the median hospital length of stay (41 [35–49] vs 27 [24–33]), ICU days (35 [30–41] vs 19 [17–24]), and ventilator days (30 [27–34] vs 15 [13–18]). All p values are less than 0.001.

CONCLUSIONS:

Approximately 2% of acute respiratory distress syndrome patients were placed on extracorporeal membrane oxygenation. The overall inhospital mortality remained high despite patients being placed on extracorporeal membrane oxygenation.

Acute Respiratory Distress Syndrome (ARDS) after trauma: Improving incidence, but increasing mortality

PURPOSE

Acute Respiratory Distress Syndrome (ARDS) is an infrequent, yet morbid inflammatory complication in injury victims. With the current project we sought to estimate trends in incidence, determine outcomes, and identify risk factors for ARDS and related mortality.

MATERIALS & METHODS

The national Trauma Quality Improvement Program dataset (2010-2014) was queried. Demographics, injury characteristics and outcomes were compared between patients who developed ARDS and those who did not. Logistic regression models were fitted for the development of ARDS and mortality respectively, adjusting for relevant confounders.

RESULTS

In the studied 808,195 TQIP patients, incidence of ARDS decreased over the study years (3-1.1%, p < 0.001), but related mortality increased (18.-21%, p = 0.001). ARDS patients spent an additional 14.7 ± 10.3 days in the hospital, 9.7 ± 7.9 in the ICU, and 6.6 ± 9.4 on mechanical ventilation (all p < 0.001). Older age, male gender, African American race increased risk for ARDS. Age, male gender, lower GCS and higher ISS also increased mortality risk among ARDS patients. Several pre-existing comorbidities including chronic alcohol use, diabetes, smoking, and respiratory disease also increased risk.

CONCLUSION

Although the incidence of ARDS after trauma appears to be declining, mortality is on the rise.

Radiomics score predicts acute respiratory distress syndrome based on the initial CT scan after trauma

OBJECTIVES

Acute respiratory distress syndrome (ARDS) constitutes a major factor determining the clinical outcome in polytraumatized patients. Early prediction of ARDS is crucial for timely supportive therapy to reduce morbidity and mortality. The objective of this study was to develop and test a machine learning-based method for the early prediction of ARDS derived from the first computed tomography scan of polytraumatized patients after admission to the hospital.

MATERIALS AND METHODS

One hundred twenty-three patients (86 male and 37 female, age 41.2 ± 16.4) with an injury severity score (ISS) of 16 or higher (31.9 ± 10.9) were prospectively included and received a CT scan within 1 h after the accident. The lungs, including air pockets and pleural effusions, were automatically segmented using a deep learning-based algorithm. Subsequently, we extracted radiomics features from within the lung and trained an ensemble of gradient boosted trees (GBT) to predict future ARDS.

RESULTS

Cross-validated ARDS prediction resulted in an area under the curve (AUC) of 0.79 for the radiomics score compared to 0.66 for ISS, and 0.68 for the abbreviated injury score of the thorax (AIS-thorax). Prediction using the radiomics score yielded an f1-score of 0.70 compared to 0.53 for ISS and 0.57 for AIS-thorax. The radiomics score achieved a sensitivity and specificity of 0.80 and 0.76.

CONCLUSIONS

This study proposes a radiomics-based algorithm for the prediction of ARDS in polytraumatized patients at the time of admission to hospital with an accuracy that competes and surpasses conventional scores despite the heterogeneous, and therefore more realistic, scanning protocols.

KEY POINTS

• Early prediction of acute respiratory distress syndrome in polytraumatized patients is possible, even when using heterogenous data. • Radiomics-based prediction resulted in an area under the curve of 0.79 compared to 0.66 for the injury severity score, and 0.68 for the abbreviated injury score of the thorax. • Highlighting the most relevant lung regions for prediction facilitates the understanding of machine learning-based prediction.

Dilemma of crystalloid resuscitation in non-exsanguinating polytrauma: what is too much?

Background

Aggressive crystalloid resuscitation increases morbidity and mortality in exsanguinating patients. Polytrauma patients with severe tissue injury and subsequent inflammatory response without major blood loss also need resuscitation. This study investigated crystalloid and blood product resuscitation in non-exsanguinating polytrauma patients and studied possible adverse outcomes.

Methods

A 6.5-year prospective cohort study included consecutive trauma patients admitted to a Level 1 Trauma Center intensive care unit (ICU) who survived 48 hours. Demographics, physiologic and resuscitation parameters in first 24 hours, Denver Multiple Organ Failure scores, adult respiratory distress syndrome (ARDS) data and infectious complications were prospectively collected. Patients were divided in 5 L crystalloid volume subgroups (0–5, 5–10, 10–15 and >15 L) to make clinically relevant comparisons. Data are presented as median (IQR); p value <0.05 was considered significant.

Results

367 patients (70% men) were included with median age of 46 (28–61) years, median Injury Severity Score was 29 (22–35) and 95% sustained blunt injuries. 17% developed multiple organ dysfunction syndrome (MODS), 4% ARDS and 14% died. Increasing injury severity, acidosis and coagulopathy were associated with more crystalloid administration. Increasing crystalloid volumes were associated with more blood products, increased ventilator days, ICU length of stay, hospital length of stay, MODS, infectious complications and mortality rates. Urgent laparotomy was found to be the most important independent predictor for crystalloid resuscitation in multinominal regression analysis. Further, fresh frozen plasma (FFP) <8 hours was less likely to be administered in patients >5 L compared with the group 0–5 L. With increasing crystalloid volume, the adjusted odds of MODS, ARDS and infectious complications increased 3–4-fold, although not statistically significant. Mortality increased 6-fold in patients who received >15 L crystalloids (p=0.03).

Discussion

Polytrauma patients received large amounts of crystalloids with few FFPs <24 hours. In patients with <10 L crystalloids, <24-hour mortality and MODS rates were not influenced by crystalloid resuscitation. Mortality increased 6-fold in patients who received >15 L crystalloids ≤24 hours. Efforts should be made to balance resuscitation with modest crystalloids and sufficient amount of FFPs.

Level of evidence

Level 3.

Study type

Population-based cohort study.

Cigarette Smoking and ARDS After Blunt Trauma: The Influence of Changing Smoking Patterns and Resuscitation Practices

BACKGROUND

Cigarette smoking is associated with an increased risk of developing ARDS. However, whether changes in smoking patterns or processes of care impact this relationship is unclear.

RESEARCH QUESTION

Are changes in smoking and resuscitation patterns associated with changes in the relationship between smoking and ARDS?

STUDY DESIGN AND METHODS

We conducted a prospective cohort study of critically injured adults with blunt trauma from 2005 to 2015. Plasma cotinine, a tobacco biomarker, was measured to categorize patients by smoking status. We used regression to assess the relationship between smoking, resuscitation practices, and ARDS over time.

RESULTS

In the overall cohort, active (OR, 1.9; 95% CI, 1.0-3.5; P = .046) and passive (OR, 2.6; 95% CI, 1.4-4.8; P = .002) smoking were associated with an increased risk of developing ARDS in multivariate analyses. In contrast to the dose-response relationship in patients enrolled from 2005 to 2008, passive cigarette smoke exposure was associated with the highest risk of developing ARDS in patients enrolled from 2009 to 2015, suggesting a threshold effect. Packed RBC (pRBC) and fresh frozen plasma (FFP) transfusions were associated with an increased risk of developing ARDS, particularly in active smokers (pRBC: OR, 5.6; P < .001; FFP: OR, 4.5; P < .001) compared with passive smokers or nonsmokers. Blood product transfusion and smoking patterns changed over time.

INTERPRETATION

Despite changes in resuscitation and smoking patterns, cigarette smoking remains associated with an increased risk of developing ARDS. However, this relationship changed over time, with passive smokers at particularly increased risk of developing ARDS in later years, which may be related to changes in smoking patterns or transfusion practices over time. These findings highlight the need for additional mechanistic and epidemiologic studies of the effects of low levels of cigarette smoke exposure on lung health.

Pneumonia in severely injured patients with thoracic trauma: results of a retrospective observational multi-centre study

Background

While the incidence and aspects of pneumonia in ICU patients has been extensively discussed in the literature, studies on the occurrence of pneumonia in severely injured patients are rare. The aim of the present study is to elucidate factors associated with the occurrence of pneumonia in severely injured patients with thoracic trauma.

Setting

Level-I University Trauma Centres associated with the TraumaRegister DGU®.

Methods

A total of 1162 severely injured adult patients with thoracic trauma documented in the TraumaRegister DGU® (TR-DGU) were included in this study. Demographic data, injury severity, duration of mechanical ventilation (MV), duration of ICU stay, occurrence of pneumonia, bronchoalveolar lavage, aspiration, pathogen details, and incidences of mortality were evaluated. Statistical evaluation was performed using SPSS (Version 25.0, SPSS, Inc.) software.

Results

The overall incidence of pneumonia was 27.5%. Compared to patients without pneumonia, patients with pneumonia had sustained more severe injuries (mean ISS: 32.6 vs. 25.4), were older (mean age: 51.3 vs. 47.5) and spent longer periods under MV (mean: 368.9 h vs. 114.9 h). Age, sex (male), aspiration, and duration of MV were all independent predictors for pneumonia occurrence in a multivariate analysis. The cut-off point for duration of MV that best discriminated between patients who would and would not develop pneumonia during their hospital stay was 102 h. The extent of thoracic trauma (AIS_thorax), ISS, and presence of pulmonary comorbidities did not show significant associations to pneumonia incidence in our multivariate analysis. No significant difference in mortality between patients with and without pneumonia was observed.

Conclusions

Likelihood of pneumonia increases with age, aspiration, and duration of MV. These parameters were not found to be associated with differences in outcomes between patients with and without pneumonia. Future studies should focus on independent parameters to more clearly identify severely injured subgroups with a high risk of developing pneumonia.

Level of evidence

Level II - Retrospective medical record review.

Nationwide cohort study of independent risk factors for acute respiratory distress syndrome after trauma

Background

The primary objective of this study was to evaluate the effect of specific direct and indirect factors that accounted, in trauma patients, for the development of acute respiratory distress syndrome (ARDS) and mortality in patients with ARDS.

Methods

We performed a retrospective cohort study of patients from the National Trauma Data Bank. Multilevel mixed-effects logistic regression was used with the development of ARDS as the primary and mortality in patients with ARDS as the secondary outcome measures. We compared trauma patients with versus without thoracic (direct) and extrathoracic (indirect) risk factors, using patient demographics, physiologic, and anatomic injury severity as covariates. Subset analysis was performed for patients with trauma-induced lung contusion (TILC) and for patients with minor (Injury Severity Score [ISS] ≤15) injury.

Results

A total of 2 998 964 patients were studied, of whom 28 597 developed ARDS. From 2011 to 2014, the incidence of ARDS decreased; however, mortality in patients with ARDS has increased. Predictors of ARDS included direct thoracic injury (TILC, multiple rib fractures, and flail chest), as well as indirect factors (increased age, male gender, higher ISS, lower Glasgow Coma Scale motor component score, history of cardiopulmonary or hematologic disease, and history of alcoholism or obesity). Patients with ARDS secondary to direct thoracic injury had a lower risk of mortality compared with patients with ARDS due to other mechanisms.

Discussion

Despite the decreasing incidence of trauma-induced ARDS, mortality in patients with ARDS has increased. Direct thoracic injury was the strongest predictor of ARDS. Knowing specific contributors to trauma-induced ARDS could help identify at-risk patients early in their hospitalization and mitigate the progression to ARDS and thereby mortality.

Level of evidence

Prognostic study, level III.

Does lack of thoracic trauma attenuate the severity of pulmonary failure? An 8-year analysis of critically injured patients

PURPOSE

Patients with thoracic trauma are presumed to be at higher risk for pulmonary dysfunction, but adult respiratory distress syndrome (ARDS) may develop in any patient, regardless of associated chest injury. This study evaluated the impact of thoracic trauma and pulmonary failure on outcomes in trauma patients admitted to the intensive-care unit (ICU).

METHODS

All trauma patients admitted to the ICU over an 8-year period were identified. Patients that died within 48 h of arrival were excluded. Patients were stratified by baseline characteristics, injury severity, development of ARDS, and infectious complications. Multiple logistic regression was used to determine variables significantly associated with the development of ARDS.

RESULTS

10,362 patients were identified. After exclusions, 4898 (50%) patients had chest injury and 4975 (50%) did not. 200 (2%) patients developed ARDS (3.6% of patients with chest injury and 0.5% of patients without chest injury). Patients with ARDS were more likely to have chest injury than those without ARDS (87% vs 49%, p < 0.001). However, of the patients without chest injury, the development of ARDS still led to a significant increase in mortality compared to those patients without ARDS (58% vs 5%, p < 0.001). Multiple logistic regression found ventilator-associated pneumonia (VAP) to be the only independent predictor for the development of ARDS in ICU patients without chest injury.

CONCLUSIONS

ARDS development was more common in patients with thoracic trauma. Nevertheless, the development of ARDS in patients without chest injury was associated with a tenfold higher risk of death. The presence of VAP was found to be the only potentially preventable and treatable risk factor for the development of ARDS in ICU patients without chest injury.

Shock Wave Therapy Enhances Mitochondrial Delivery into Target Cells and Protects against Acute Respiratory Distress Syndrome

This study tested the hypothesis that shock wave therapy (SW) enhances mitochondrial uptake into the lung epithelial and parenchymal cells to attenuate lung injury from acute respiratory distress syndrome (ARDS). ARDS was induced in rats through continuous inhalation of 100% oxygen for 48 h, while SW entailed application 0.15 mJ/mm² for 200 impulses at 6 Hz per left/right lung field. In vitro and ex vivo studies showed that SW enhances mitochondrial uptake into lung epithelial and parenchyma cells (all p < 0.001). Flow cytometry demonstrated that albumin levels and numbers of inflammatory cells (Ly6G+/CD14+/CD68+/CD11^b/c+) in bronchoalveolar lavage fluid were the highest in untreated ARDS, were progressively reduced across SW, Mito, and SW + Mito (all p < 0.0001), and were the lowest in sham controls. The same profile was also seen for fibrosis/collagen deposition, levels of biomarkers of oxidative stress (NOX-1/NOX-2/oxidized protein), inflammation (MMP-9/TNF-α/NF-κB/IL-1β/ICAM-1), apoptosis (cleaved caspase 3/PARP), fibrosis (Smad3/TGF-β), mitochondrial damage (cytosolic cytochrome c) (all p < 0.0001), and DNA damage (γ-H2AX+), and numbers of parenchymal inflammatory cells (CD11+/CD14+/CD40L+/F4/80+) (p < 0.0001). These results suggest that SW-assisted Mito therapy effectively protects the lung parenchyma from ARDS-induced injury.

Optimal ventilator strategies for trauma-related ARDS

BACKGROUND

Acute respiratory distress syndrome (ARDS) was first described in the 1960s and has become a major area of research due to the mortality and morbidity associated with it. ARDS is currently defined using the Berlin Consensus; however, this is not wholly applicable for trauma-related ARDS.

METHODS

A systematic review of the literature was undertaken using the Preferred Reporting for Systematic Reviews and Meta Analyses methodology. The Ovid Medline, Web of Science and PubMed online databases were interrogated for papers published between 1 January 1995 and 31 December 2017.

RESULTS

The literature search yielded a total of 64 papers that fulfilled the search criteria.

CONCLUSIONS

Despite decades of dedicated research into different treatment modalities, ARDS continues to carry a high burden of mortality. The ARDS definitions laid out in the Berlin consensus are not entirely suited to trauma. While trauma-related ARDS represents a small portion of the available research, the evidence continues to favour low tidal volume ventilation as the benchmark for current practice. Positive end expiratory ventilation and airway pressure release ventilation in trauma cohorts may be beneficial; however, the evidence to date does not show this.

Post-ICU psychological morbidity in very long ICU stay patients with ARDS and delirium

PURPOSE

We investigated the impact of delirium on illness severity, psychological state, and memory in acute respiratory distress syndrome patients with very long ICU stay.

MATERIALS AND METHODS

Prospective cohort study in the medical-surgical ICUs of 2 teaching hospitals. Very long ICU stay (>75days) and prolonged delirium (≥40days) thresholds were determined by ROC analysis. Subjects were ≥18years, full-code, and provided informed consent. Illness severity was assessed using Acute Physiology and Chronic Health Evaluation IV, Simplified Acute Physiology Score-3, and Sequential Organ Failure Assessment scores. Psychological impact was assessed using the Hospital Anxiety and Depression Scale, Impact of Event Scale-Revised, and the 14-question Post-Traumatic Stress Syndrome (PTSS-14). Memory was assessed using the ICU Memory Tool survey.

RESULTS

181 subjects were included. Illness severity did not correlate with delirium duration. On logistic regression, only PTSS-14<49 correlated with delirium (p=0.001; 95% CI 1.011, 1.041). 49% remembered their ICU stay clearly. 47% had delusional memories, 50% reported intrusive memories, and 44% reported unexplained feelings of panic or apprehension.

CONCLUSION

Delirium was associated with memory impairment and PTSS-14 scores suggestive of PTSD, but not illness severity.