Prehospital triage for mass casualty incidents using the META method for early surgical assessment: retrospective validation of a hospital trauma registry.

BACKGROUND: In mass casualty incidents (MCI), death usually occurs within the first few hours and thus early transfer to a trauma centre can be crucial in selected cases. However, most triage systems designed to prioritize the transfer to hospital of these patients do not assess the need for surgery, in part due to inconclusive evidence regarding the value of such an assessment. Therefore, the aim of the present study was to evaluate the capacity of a new triage system-the Prehospital Advanced Triage Method (META)-to identify victims who could benefit from urgent surgical assessment in case of MCI. METHODS: Retrospective, descriptive, observational study of a multipurpose cohort of patients included in the severe trauma registry of the Gregorio Marañón University General Hospital (Spain) between June 1993 and December 2011. All data were prospectively evaluated. All patients were evaluated with the META system to determine whether they met the criteria for urgent transfer. The META defines patients in need of urgent surgical assessment: (a) All penetrating injuries to head, neck, torso and extremities proximal to elbow or knee, (b) Open pelvic fracture, (c) Closed pelvic fracture with mechanical or haemodynamic instability and (d) Blunt torso trauma with haemodynamic instability. Patients who fulfilled these criteria were designated as "Urgent Evacuation for Surgical Assessment" (UESA) cases; all other cases were designated as non-UESA. The following variables were assessed: patient status at the scene; severity scales [RTS, Shock index, MGAP (Mechanism, Glasgow coma scale, Age, pressure), GCS]; need for surgery and/or interventional procedure to control bleeding (UESA); and mortality. The two groups (UESA vs. non-UESA) were then compared. RESULTS: A total of 1882 cases from the database were included in the study. Mean age was 39.2 years and most (77%) patients were male. UESA patients presented significantly worse on-scene hemodynamic parameters (systolic blood pressure and heart rate) and greater injury severity (RTS, shock index, and MGAP scales). No differences were observed for respiratory rate, need for orotracheal intubation, or GCS scores. The anatomical injuries of patients in the UESA group were less severe but these patients had a greater need for urgent surgery and higher mortality rates. CONCLUSION: These findings suggest that the META triage classification system could be beneficial to help identify patients with severe trauma and/or in need of urgent surgical assessment at the scene of injury in case of MCI. These findings demonstrate that, in this cohort, the META fulfils the purpose for which it was designed.

Assessment of bullet effectiveness based on a human vulnerability model.

INTRODUCTION: Penetrating wounds from explosively propelled fragments and bullets are the most common causes of combat injury. There is a requirement to assess the potential effectiveness of bullets penetrating human tissues in order to optimise preventive measures and wound trauma management. METHODS: An advanced voxel model based on the Chinese Visible Human data was built. A digital human vulnerability model was established in combination with wound reconstruction and vulnerability assessment rules, in which wound penetration profiles were obtained by recreating the penetration of projectiles into ballistic gelatin. An effectiveness evaluation method of bullet penetration using the Abbreviated Injury Scale (AIS) was developed and solved using the Monte Carlo sampling method. RESULTS: The effectiveness of rifle bullets was demonstrated to increase with increasing velocity in the range of 300-700 m/s. When imparting the same energy, the effectiveness of the 5.56 mm bullet was higher than the 7.62 mm bullet in this model. CONCLUSIONS: The superimposition of simulant penetration profiles produced from ballistic gelatin simulant has been used to predict wound tracts in damaged tissues. The authors recognise that determining clinical effectiveness based on the AIS scores alone without verification of outcome by review of clinical hospital records means that this technique should be seen more as a manner of comparing the effectiveness of bullets than an injury prediction model.

A comparison of base deficit and vital signs in the early assessment of patients with penetrating trauma in a high burden setting.

INTRODUCTION: An assessment of physiological status is a key step in the early assessment of trauma patients with implications for triage, investigation and management. This has traditionally been done using vital signs. Previous work from large European trauma datasets has suggested that base deficit (BD) predicts clinically important outcomes better than vital signs (VS). A BD derived classification of haemorrhagic shock appeared superior to one based on VS derived from ATLS criteria in a population of predominantly blunt trauma patients. The initial aim of this study was to see if this observation would be reproduced in penetrating trauma patients. The power of each individual variable (BD, heart rate (HR), systolic blood pressure (SBP), shock index(SI) (HR/SBP) and Glasgow Coma Score (GCS)) to predict mortality was then also compared. METHODS: A retrospective analysis of adult trauma patients presenting to the Pietermaritzburg Metropolitan Trauma Service was performed. Patients were classified into four "shock" groups using VS or BD and the outcomes compared. Receiver Operator Characteristic (ROC) curves were then generated to compare the predictive power for mortality of each individual variable. RESULTS: 1863 patients were identified. The overall mortality rate was 2.1%. When classified by BD, HR rose and SBP fell as the "shock class" increased but not to the degree suggested by the ATLS classification. The BD classification of haemorrhagic shock appeared to predict mortality better than that based on the ATLS criteria. Mortality increased from 0.2% (Class 1) to 19.7% (Class 4) based on the 4 level BD classification. Mortality increased from 0.3% (Class 1) to 12.6% (Class 4) when classified based by VS. Area under the receiver operator characteristic (AUROC) curve analysis of the individual variables demonstrated that BD predicted mortality significantly better than HR, GCS, SBP and SI. AUROC curve (95% Confidence Interval (CI)) for BD was 0.90 (0.85-0.95) compared to HR 0.67(0.56-0.77), GCS 0.70(0.62-0.79), SBP 0.75(0.65-0.85) and SI 0.77(0.68-0.86). CONCLUSION: BD appears superior to vital signs in the immediate physiological assessment of penetrating trauma patients. The use of BD to assess physiological status may help refine their early triage, investigation and management.

Examination of endothelial cell-induced epidermal regeneration in a mice-based chimney wound model.

As wound contraction in the cutaneous layer occurs rapidly in mice, mechanical means are typically used to deliberately expose the wound to properly investigate healing by secondary intention. Previously, silicon rings and splinting models were attempted to analyze histological recovery but prevention of surrounding epidermal cell migration and subsequent closure was minimal. Here, we developed an ideal chimney wound model to evaluate epidermal regeneration in murine under hESC-EC transplantation through histological analysis encompassing the three phases of regeneration: migration, proliferation, and remodeling. Human embryonic stem cell derived endothelial cells (hESC-EC) were transplanted due to possessing a well-known therapeutic effect in angiogenesis which also enhances epidermal repair to depict the process of regeneration. Following a standard 1 mm biopsy punch, a chimney manufactured by modifying a 1.7 mL microtube was simply inserted into the excisional wound to complete the modeling process. Under this model, the excisional wound remained fully exposed for 14 days and even after 4 weeks, only a thin transparent layer of epidermal tissue covered the wound site. This approach is able to more accurately depict epidermal repair in relation to histology while also being a user-friendly and cost-effective way to mimic human recovery in rodents and evaluate epithelial repair induced by a form of therapy.

An assessment of wound healing potential of Argyreia speciosa leaves.

In North India, poultice of young unfolded leaves of Argyreia speciosa Linn. (Convolvulaceae) is used for healing wounds. In order to find scientific evidence for the traditional utilization of leaves of A. speciosa in wound healing, this investigation was carried out. A linear incision wound of about 3 cm in length and 2 mm in depth and circular excision wound of 177 mm(2) full thickness were made on the dorsal region of separate groups (n = 5) of anesthetized Swiss albino mice. A simple ointment, developed by including ethanol, ethanol-water, and water extracts (10% each, separately) of A. speciosa, was applied topically to mice once daily for 14 days after wounding. To evaluate the effect of each extract, wound contraction, epithelization period, wound breaking strength, and hydroxyproline content were determined. The water extract of A. speciosa showed accelerated wound healing activity as evidenced by fast wound contraction (96.30 ± 0.52%; P < 0.01), rapid epithelization period (11.40 ± 0.60 days; P < 0.001), greater wound breaking strength (376.56 ± 21.16 g; P < 0.001), and higher hydroxyproline content (16.49 ± 1.12 mg/g; P < 0.05) of granulation tissue. The present report supports the traditional use of Argyreia speciosa leaves for wound healing and signify its relevant therapeutic potential.

Histological assessment of the effect of laser irradiation on skin wound healing in rats.

OBJECTIVE: The purpose of this study was to evaluate, from the histological point of view, the effect of diode laser irradiation on skin wound healing in Sprague-Dawley rats. BACKGROUND DATA: Various biological effects have been described in different studies after low-level laser therapy (LLLT). METHODS: Two parallel full-thickness skin incisions were performed on the back of each rat (n = 49) and immediately sutured. After surgery, one wound of each rat was exposed to laser irradiation (continuous mode, 670 nm, daily dose 30 J/cm2), whereas the parallel wound was not irradiated and served as control. Both wounds were removed 24, 48, 72, 96, 120, 144, and 168 h after surgery and routinely fixed and embedded in paraffin sections, stained with hematoxylin and eosin, van Gieson, periodic acid Schiff + periodic acid Schiff diastase, Mallory's phosphotungstic hematoxylin, and azur and eosin, and histopathologically evaluated. RESULTS: As compared to nonirradiated control wounds, laser stimulation shortened the inflammatory phase as well as accelerated the proliferative and maturation phase, and positively stimulated the regeneration of injured epidermis and the reparation of injured striated muscle. CONCLUSION: LLLT at 670 nm positively influences all phases of rat skin wound healing.

Assessment of initial base deficit as a predictor of outcome: mechanism of injury does make a difference.

Initial base deficit in injured patients has been shown to predict the adequacy of resuscitation and outcome. The usefulness of base deficit as a predictor of outcome, however, may be dependent on the mechanism of injury. We conducted a retrospective review of the trauma registry, supplemented by chart review, of all trauma patients treated at a Level I trauma center from January 1995 through July 2001. Data collected included mechanism of injury, base deficit, Injury Severity Score, and outcome. From 1995 through 2001 a total of 3275 patients (23% of trauma admissions) at a mean age of 34 +/- 15 years had a base deficit recorded at the time of admission. The patients were 78 per cent male, and the mechanism of injury was blunt trauma in 58.2 per cent. Mortality increased with successive increases in base deficit but was markedly lower for a given base deficit in those patients having sustained stab wounds and/or severe lacerations as compared with those with gunshot wounds or blunt trauma. The value of the base deficit as a predictor of outcome depends upon the mechanism of injury and appears most useful for patients sustaining gunshot wounds or blunt trauma. Future studies in patients with penetrating trauma using base deficit as a predictor of outcome should separate patients with gunshot wounds from those with stab wounds or lacerations.