Predictors of initial management failure in traumatic hemothorax: A prospective multicenter cohort analysis

BACKGROUND

Traumatic hemothorax is common, and management failure leads to worse outcomes. We sought to determine predictive factors and understand the role of trauma center performance in hemothorax management failure.

METHODS

We prospectively examined initial hemothorax management (observation, pleural drainage, surgery) and failure requiring secondary intervention in 17 trauma centers. We defined hemothorax management failure requiring secondary intervention as thrombolytic administration, tube thoracostomy, image-guided drainage, or surgery after failure of the initial management strategy at the discretion of the treating trauma surgeon. Patient-level predictors of hemothorax management failure requiring secondary intervention were identified for 2 subgroups: initial observation and immediate pleural drainage. Trauma centers were divided into quartiles by hemothorax management failure requiring secondary intervention rate and hierarchical logistic regression quantified variation.

RESULTS

Of 995 hemothoraces in 967 patients, 186 (19%) developed hemothorax management failure requiring secondary intervention. The frequency of hemothorax management failure requiring secondary intervention increased from observation to pleural drainage to surgical intervention (12%, 22%, and 35%, respectively). The number of ribs fractured (odds ratio 1.12 per fracture; 95% confidence interval 1.00-1.26) and pulmonary contusion (odds ratio 2.25, 95% confidence interval 1.03-4.91) predicted hemothorax management failure requiring secondary intervention in the observation subgroup, whereas chest injury severity (odds ratio 1.58; 95% confidence interval 1.17-2.12) and initial hemothorax volume evacuated (odds ratio 1.10 per 100 mL; 95% confidence interval 1.05-1.16) predicted hemothorax management failure requiring secondary intervention after pleural drainage. After adjusting for patient characteristics in the logistic regression model for hemothorax management failure requiring secondary intervention, patients treated at high hemothorax management failure requiring secondary intervention trauma centers were 6 times more likely to undergo an intervention after initial hemothorax management failure than patients treated in low hemothorax management failure requiring secondary intervention trauma centers (odds ratio 6.18, 95% confidence interval 3.41-11.21).

CONCLUSION

Failure of initial management of traumatic hemothorax is common and highly variable across trauma centers. Assessing patient selection for a given management strategy and center-level practices represent opportunities to improve outcomes from traumatic hemothorax.

Crystalloid resuscitation in trauma patients: deleterious effect of 5L or more in the first 24h

BACKGROUND

Over-aggressive intravenous fluid therapy with crystalloids has adverse effects in trauma patients. We assessed the role of large-volume (≥5l) administration of crystalloids within 24h of injury as an independent risk-factor for mortality, in-hospital complications, and prolonged mechanical ventilation.

METHODS

A retrospective cohort analysis of adult trauma patients admitted to a level 1-trauma center between December 2011 and December 2012. Patient demographics, clinical and laboratory values, and total resuscitation fluid administered within the first 24h of injury were obtained. Outcomes included mortality, in-hospital complications and ventilator-days. Multivariable logistic regression and Poisson regression analyses were performed to investigate any association between the administration of ≥5L crystalloids with the aforementioned outcomes while controlling for selected clinical variables.

RESULTS

A total of 970 patients were included in the analysis. 264 (27%) received ≥5L of crystalloids in the first 24h of injury. 118 (12%) had in-hospital complications and 337 (35%) required mechanical ventilation. The median age was 46 years (interquartile range (IQR) 27-65) years and 73% (n = 708) were males. The median injury severity score (ISS) was 17 (IQR 9-25). Overall mortality rate was 7% (n = 67). Multivariable logistic regression analysis showed several variables independently associated with mortality (p < 0.05), including resuscitation with ≥5L crystalloid in the first 24h (adjusted odds ratio (aOR) 2.55), older age (aOR 1.03), higher ISS (aOR 1.09), and lower temperature (aOR 0.68). The variables independently associated with in-hospital complications (p < 0.05) were older age, longer ICU stay, and platelet transfusion within 24h of the injury. Need for mechanical ventilation was more common in patients who received ≥5L crystalloids (RR 2.31) had higher ISS (RR 1.02), developed in-hospital complications (RR 1.91) and had lower presenting temperature (RR 0.87).

CONCLUSION

Large-volume crystalloid resuscitation is associated with increased mortality and longer time ventilated, but not with in-hospital complications such as pneumonia and sepsis. Based on this data, we recommend judicious use of crystalloids in the resuscitation of trauma patients.

Fresh frozen plasma: red blood cells (1:2) coagulation effect is equivalent to 1:1 and whole blood

BACKGROUND

Preemptive treatment of trauma-associated coagulopathy involves transfusion of fresh frozen plasma (FFP) at 1:1 ratio with red blood cells (RBCs), but the optimal ratio remains controversial. In combat theaters, fresh whole blood (FWB) is also an option. The objective of this study was to determine the effect of FFP:RBC ratios 1:1, 1:2, 1:3 and FWB on coagulation during resuscitation.

MATERIALS AND METHODS

Thirty-six rats were randomized in the following six groups: Group 1: sham; Group 2: hemorrhage followed by sole lactated Ringer (LR) infusion; Group 3: FFP:RBC (1:1); Group 4: FFP:RBC (1:2); Group 5: FFP:RBC (1:3); Group 6: FWB transfusion. Another 25 animals were used for blood harvesting. Hemorrhage was induced by withdrawing 40% of total blood volume, mean arterial pressure (MAP) decreased to 45% of baseline, and laparotomy. Animals underwent LR infusion followed by blood product transfusion preset for each group. Blood samples were obtained at baseline and in the 105th minute for thromboelastometry and lactate.

RESULTS

Hemorrhage caused a significant decrease in MAP and increase in lactate (P < 0.05). MAP was persistently low in group 2 despite fluid infusion (P < 0.05), but not in the other groups after 20 min of resuscitation. Mean clot formation time, alpha angle, and maximum clot firmness decreased significantly (P < 0.05) in group 2 (LR) and group 5 (1:3) compared with other groups.

CONCLUSIONS

FFP:RBC in a 1:2 ratio optimally harnessed hemostatic resuscitation and prudent use of blood products compared with 1:1 and 1:3 ratios and to FWB transfusion.

Gallstone ileus obstructing within an incarcerated lumbar hernia: an unusual presentation of a rare diagnosis

We describe an unusual case of a 74-year-old woman who presented with signs and symptoms of small-bowel obstruction and a clinically appreciable, irreducible, left-sided lumbar hernia associated with previous iliac crest bone graft harvesting. Palpation of the hernia demonstrated a small, firm mass within the loops of herniated bowel. CT scanning recognised an intraluminal gallstone at the transition point, establishing the diagnosis of gallstone ileus within an incarcerated lumbar hernia. The proposed explanatory mechanism is that of a gallstone migrating into an easily reducible hernia containing small bowel causing obstruction at the hernia neck by a ball-valve mechanism, resulting in proximal bowel dilation and thus hernia incarceration; it remains unclear when the stone entered the hernia, and whether it enlarged in situ or prior to entering the enteral tract. This is only the second reported instance in the literature of an intraluminal gallstone causing hernia incarceration.

Vagus nerve stimulation improves coagulopathy in hemorrhagic shock: a thromboelastometric animal model study

Introduction

Inflammation plays a major role in the multifactorial process of trauma associated coagulopathy. The vagus nerve regulates the cholinergic anti-inflammatory pathway. We hypothesized that efferent vagus nerve stimulation (VNS) can improve coagulopathy by modulating the inflammatory response to hemorrhage.

Methods

Wistar rats (n = 24) were divided in 3 groups: Group (G1) Sham hemorrhagic shock (HS); (G2) HS w/o VNS; (G3) HS followed by division of the vagus nerves and VNS of the distal stumps. Hemorrhage (45% of baseline MAPx15 minutes) was followed by normotensive resuscitation with LR. Vagus nerves were stimulated (3.5 mA, 5 Hz) for 30 sec 7 times. Samples were obtained at baseline and at 60 minutes for thromboelastometry (Rotem®) and cytokine assays (IL-1 and IL-10). ANOVA was used for statistical analysis; significance was set at p < 0.05.

Results

Maximum clot firmness (MCF) significantly decreased in G2 after HS (71.5 ± 1.5 vs. 64 ± 1.6) (p < 0.05). MCF significantly increased in G3 compared to baseline (67.3 ± 2.7 vs. 71.5 ± 1.2) (p < 0.05). G3 also showed significant improvement in Alfa angle, and Clot Formation Time (CFT) compared to baseline. IL-1 increased significantly in group 2 and decrease in group 3, while IL-10 increased in group 3 (p < 0.05).

Conclusions

Electrical stimulation of efferent vagus nerves, during resuscitation (G3), decreases inflammatory response to hemorrhage and improves coagulation.

Abdominal catastrophes in the intensive care unit setting

Patients in the setting of the intensive care unit can develop intra-abdominal complications that may worsen outcome. Clinical suspicion of such complications coupled with early diagnosis and treatment may reduce morbidity and mortality associated with these processes. This article addresses the diagnosis and management of some of the common causes of intra-abdominal catastrophes.

Permissive hypotension does not reduce regional organ perfusion compared to normotensive resuscitation: animal study with fluorescent microspheres

Introduction

The objective of this study was to investigate regional organ perfusion acutely following uncontrolled hemorrhage in an animal model that simulates a penetrating vascular injury and accounts for prehospital times in urban trauma. We set forth to determine if hypotensive resuscitation (permissive hypotension) would result in equivalent organ perfusion compared to normotensive resuscitation.

Methods

Twenty four (n=24) male rats randomized to 4 groups: Sham, No Fluid (NF), Permissive Hypotension (PH) (60% of baseline mean arterial pressure - MAP), Normotensive Resuscitation (NBP). Uncontrolled hemorrhage caused by a standardised injury to the abdominal aorta; MAP was monitored continuously and lactated Ringer’s was infused. Fluorimeter readings of regional blood flow of the brain, heart, lung, kidney, liver, and bowel were obtained at baseline and 85 minutes after hemorrhage, as well as, cardiac output, lactic acid, and laboratory tests; intra-abdominal blood loss was assessed. Analysis of variance was used for comparison.

Results

Intra-abdominal blood loss was higher in NBP group, as well as, lower hematocrit and hemoglobin levels. No statistical differences in perfusion of any organ between PH and NBP groups. No statistical difference in cardiac output between PH and NBP groups, as well as, in lactic acid levels between PH and NBP. NF group had significantly higher lactic acidosis and had significantly lower organ perfusion.

Conclusions

Hypotensive resuscitation causes less intra-abdominal bleeding than normotensive resuscitation and concurrently maintains equivalent organ perfusion. No fluid resuscitation reduces intra-abdominal bleeding but also significantly reduces organ perfusion.

A technical modification for percutaneous tracheostomy: prospective case series study on one hundred patients

The purpose of this study is to describe a technical modification of percutaneous tracheostomy that combines principles of the Percu Twist™ and the Griggs-Portex® methods in a reusable kit. One hundred patients underwent the procedure. There were no false passage, tube misplacement, or deaths related to the procedure. There were two minor bleedings managed conservatively. The technical modification described in this study is safe and simple to execute.

Rabbit model of uncontrolled hemorrhagic shock and hypotensive resuscitation

Clinically relevant animal models capable of simulating traumatic hemorrhagic shock are needed. We developed a hemorrhagic shock model with male New Zealand rabbits (2200-2800 g, 60-70 days old) that simulates the pre-hospital and acute care of a penetrating trauma victim in an urban scenario using current resuscitation strategies. A laparotomy was performed to reproduce tissue trauma and an aortic injury was created using a standardized single puncture to the left side of the infrarenal aorta to induce hemorrhagic shock similar to a penetrating mechanism. A 15-min interval was used to simulate the arrival of pre-hospital care. Fluid resuscitation was then applied using two regimens: normotensive resuscitation to achieve baseline mean arterial blood pressure (MAP, 10 animals) and hypotensive resuscitation at 60% of baseline MAP (10 animals). Another 10 animals were sham operated. The total time of the experiment was 85 min, reproducing scene, transport and emergency room times. Intra-abdominal blood loss was significantly greater in animals that underwent normotensive resuscitation compared to hypotensive resuscitation (17.1 ± 2.0 vs 8.0 ± 1.5 mL/kg). Antithrombin levels decreased significantly in normotensive resuscitated animals compared to baseline (102 ± 2.0 vs 59 ± 4.1%), sham (95 ± 2.8 vs 59 ± 4.1%), and hypotensive resuscitated animals (98 ± 7.8 vs 59 ± 4.1%). Evidence of re-bleeding was also noted in the normotensive resuscitation group. A hypotensive resuscitation regimen resulted in decreased blood loss in a clinically relevant small animal model capable of reproducing hemorrhagic shock caused by a penetrating mechanism.

Occult pneumomediastinum in blunt chest trauma: clinical significance

INTRODUCTION

Thoracic injuries are potentially responsible for 25% of all trauma deaths. Chest X-ray is commonly used to screen patients with chest injury. However, the use of computed tomography (CT) scan for primary screening is increasing, particularly for blunt trauma. CT scans are more sensitive than chest X-ray in detecting intra-thoracic abnormalities such as pneumothoraces and pneumomediastinums. Pneumomediastinum detected by chest X-ray or "overt pneumomediastinum", raises the concern of possible aerodigestive tract injuries. In contrast, there is scarce information on the clinical significance of pneumomediastinum diagnosed by CT scan only or "occult pneumomediastinum". Therefore we investigated the clinical consequences of occult pneumomediastinum in our blunt trauma population.

METHODS

A 2-year retrospective chart review of all blunt chest trauma patients with initial chest CT scan admitted to a level I trauma centre. Data extracted from the medical records include; demographics, occult, overt, or no pneumomediastinum, the presence of intra-thoracic aerodigestive tract injuries (trachea, bronchus, and/or esophagus), mechanism and severity of injury, endotracheal intubation, chest thoracostomy, operations and radiological reports by an attending radiologist. All patients with intra-thoracic aerodigestive tract injuries from 1994 to 2004 were also investigated.

RESULTS

Of 897 patients who met the inclusion criteria 839 (93.5%) had no pneumomediastinum. Five patients (0.6%) had overt pneumomediastinum and 53 patients (5.9%) had occult pneumomediastinum. Patients with occult pneumomediastinum had significantly higher ISS and AIS chest (p<0.0001) than patients with no pneumomediastinum. A chest thoracostomy tube was more common (p<0.0001) in patients with occult pneumomediastinum (47.2%) than patients with no pneumomediastinum (10.4%), as well as occult pneumothorax. None of the patients with occult pneumomediastinum had aerodigestive tract injuries (95%CI 0-0.06). Follow up CT scan of patients with occult pneumomediastinum showed complete resolution in all cases, in average 3 h after the initial exam.

CONCLUSION

Occult pneumomediastinum occurred in approximately 6% of all trauma patients with blunt chest injuries in our institution. Patients who had occult pneumomediastinum were more severely injured than those who without. However, none of the patients with occult pneumomediastinum had aerodigestive tract injuries and follow up chest CT scans demonstrated their complete and spontaneous resolution.

The Abdominal Compartment Syndrome as a Second Insult During Systemic Neutrophil Priming Provokes Multiple Organ Injury

In our recent clinical study of damage control laparotomy, the abdominal compartment syndrome (ACS) emerged as an independent risk factor for postinjury multiple organ failure (MOF). We and others have shown previously that the ACS promotes the systemic production of proinflammatory cytokines. Our study objective was to develop a clinically relevant two-event animal model of postinjury MOF using the ACS as a second insult during systemic neutrophil priming to provoke organ dysfunction. Male adult rats underwent hemorrhagic shock (30 mmHg x 45 min) and were resuscitated with crystalloids and shed blood. The timing of postshock systemic neutrophil (PMN) priming was determined by the surface expression of CD11b via flow cytometry. Finding maximal PMN priming at 8 h, but no priming at 2 h (early) and 18 h (late), the ACS (25 mmHg x 60 min) was introduced at these time points. At 24 h postshock, lung injury was assessed by lung elastase concentration and Evans blue dye extravasation in bronchoalveolar lavage. Liver and renal injuries were determined by serum alanine aminotransferase, serum creatinine, and blood urea nitrogen. The ACS during the time of maximal systemic PMN priming (8 h) provoked lung and liver injury, but did not if introduced at 2 or 18 h postshock when there was no evidence of systemic PMN priming. The 24-h mortality of this two-event model was 33%. These findings corroborate the potential for the ACS to promote multiple organ injury when occurring at the time of systemic PMN priming. This clinically relevant two-event animal model of PMN organ injury may be useful in elucidating therapy strategies to prevent postinjury MOF.

Systemic inflammatory response secondary to abdominal compartment syndrome: stage for multiple organ failure

BACKGROUND

The abdominal compartment syndrome (ACS) has been implicated in the pathogenesis of postinjury multiple organ failure. The ACS is defined as intra-abdominal hypertension causing adverse physiologic response. This study was designed to determine the effects of IAH on the production of interleukin-1b (IL-1beta), interleukin-6 (IL-6), tumor necrosis factor (TNF-alpha), and the effects on remote organ injury.

METHODS

IAH was induced in Sprague-Dawley rats which were divided into 5 groups, 10 animals each. Intra-abdominal pressure (IAP) was increased to 20 mm Hg for 60 and 90 minutes in two different groups. In a third group following IAP of 20 mm Hg the abdomen was decompressed for 30 minutes before samples were collected. The other animals were used as controls. Hemodynamic response was monitored throughout the procedure. Cytokine levels were assessed in the plasma. Remote organ injury was assessed by histopathology and myeloperoxidase activity.

RESULTS

IAH caused a significant decrease in MAP. After abdominal decompression MAP returned to baseline levels. A significant decrease in arterial pH was also noted. Increase in the levels of TNF-alpha and IL-6 was noted 30 minutes after abdominal decompression. Plasma concentration of IL-1b was elevated after 60 minutes of IAH. Abdominal decompression, however, did not cause a significant increase in the levels of this cytokine. Lung neutrophil accumulation was significantly elevated only after abdominal decompression. Histopathological findings showed intense pulmonary inflammatory infiltration including atelectasis and alveolar edema.

CONCLUSIONS

IAH provokes the release of pro-inflammatory cytokines which may serve as a second insult for the induction of MOF.