siRNA-mediated reduction of a circulating protein in swine using lipid nanoparticles

Genetic manipulation of animal models is a fundamental research tool in biology and medicine but is challenging in large animals. In rodents, models can be readily developed by knocking out genes in embryonic stem cells or by knocking down genes through in vivo delivery of nucleic acids. Swine are a preferred animal model for studying the cardiovascular and immune systems, but there are limited strategies for genetic manipulation. Lipid nanoparticles (LNPs) efficiently deliver small interfering RNA (siRNA) to knock down circulating proteins, but swine are sensitive to LNP-induced complement activation-related pseudoallergy (CARPA). We hypothesized that appropriately administering optimized siRNA-LNPs could knock down circulating levels of plasminogen, a blood protein synthesized in the liver. siRNA-LNPs against plasminogen (siPLG) reduced plasma plasminogen protein and hepatic plasminogen mRNA levels to below 5% of baseline values. Functional assays showed that reducing plasminogen levels modulated systemic blood coagulation. Clinical signs of CARPA were not observed, and occasional mild and transient hepatotoxicity was present in siPLG-treated animals at 5 h post-infusion, which returned to baseline by 7 days. These findings advance siRNA-LNPs in swine models, enabling genetic engineering of blood and hepatic proteins, which can likely expand to proteins in other tissues in the future.

Practical Guide to Education Program Evaluation Research

This Guide to Statistics and Methods describes common methods for building evidence of validity for a program within health professional education and provides a framework for program evaluation.

Early career acute care surgeons' priorities and perspectives: A mixed-methods analysis to better understand full-time employment

BACKGROUND

Understanding the expectations of early career acute care surgeons will help clarify the practice and employment models that will attract and retain high-quality surgeons, thereby sustaining our workforce. This study aimed to outline the clinical and academic preferences and priorities of early career acute care surgeons and to better define full-time employment.

METHODS

A survey on clinical responsibilities, employment preferences, work priorities, and compensation was distributed to early career acute care surgeons in the first 5 years of practice. A subset of agreeable respondents underwent virtual semistructured interviews. Both quantitative and thematic analysis were used to describe current responsibilities, expectations, and perspectives.

RESULTS

Of 471 surgeons, 167 responded (35%), the majority of whom were assistant professors within the first 3 years of practice (80%). The median desired clinical volume was 24 clinical weeks and 48 call shifts per year, 4 weeks less than their median current clinical volume. Most respondents (61%) preferred a service-based model. The top priorities cited in choosing a job were geography, work schedule, and compensation. Qualitative interviews identified themes related to defining full-time employment, first job expectations and realities, and the often-misaligned system and surgeon.

CONCLUSION

Understanding the perspectives of early career surgeons entering the workforce is important particularly in the field of acute care surgery where no standard workload or practice model exists. The wide variety of expectations, practice models, and schedule preferences may lead to a mismatch between surgeon desires and employment expectation. Consistent employment standards across our specialty would provide a framework for sustainability.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level III.

Mechanical Ventilation Does Not Predict Pneumothorax Observation Failure in the Severely Injured

BACKGROUND

Observative management of small traumatic pneumothoraces (PTX) has been shown to decrease chest tube utilization in non-mechanically ventilated patients without compromising outcomes. This approach could be used in mechanically ventilated (MV) patients, though many feel these patients are at increased risk of observation failure.

METHODS

A single center retrospective study of all adults undergoing observation of a computed tomography (CT) diagnosed PTX from 2015-2019. Patients with chest tube placement within 4-hours of arrival, concurrent hemothorax, or death within 24-hours were excluded. Observation failure was defined as chest tube placement.

RESULTS

Of 340 patients, 64 were on MV. The groups were of similar age, BMI, underlying pulmonary comorbidities, and PTX size (10.1 mm vs 8.8 mm, P = .20). The MV group was more severely injured (ISS [25+] [60.9% vs 11.2%, P < .001]). There was no difference in observation failure rates by MV status overall (6.3% vs 5.1%, P = .75) or by PTX size (<15 mm [5% vs 2.2%, P = .37], <20 mm [4.8% vs 3.1%, P = .45], <25 mm [4.8% vs 4.1%, P = .73], <30 mm [4.8% vs 4.1%, P = .73], <35 mm [4.8% vs 4.7%, P = 1.00]). MV was not an independent predictor of observation failure on multivariable analysis (OR .64, 95% CI .18-2.20), though PTX size was (OR 1.11, 95% CI 1.05-1.17). When comparing those who failed vs those who did not, the only difference was PTX size (9.34 mm vs 19.41 mm, P < .001).

CONCLUSION

MV is not an independent predictor of PTX observation failure. While PTX size appears to play a role, further studies are needed to outline safe parameters for observation in those undergoing MV.

Pediatric emergency resuscitative thoracotomy: A Western Trauma Association, Pediatric Trauma Society, and Eastern Association for the Surgery of Trauma collaborative critical decisions algorithm

LEVEL OF EVIDENCE

Literature synthesis and expert opinion, Level V.

Management of complicated diaphragmatic hernia in the acute setting: a WSES position paper

BACKGROUND

Diaphragmatic hernia (DH) presenting acutely can be a potentially life-threatening condition. Its management continues to be debatable.

METHODS

A bibliographic search using major databases was performed using the terms "emergency surgery" "diaphragmatic hernia," "traumatic diaphragmatic rupture" and "congenital diaphragmatic hernia." GRADE methodology was used to evaluate the evidence and give recommendations.

RESULTS

CT scan of the chest and abdomen is the diagnostic gold standard to evaluate complicated DH. Appropriate preoperative assessment and prompt surgical intervention are important for a clinical success. Complicated DH repair is best performed via the use of biological and bioabsorbable meshes which have proven to reduce recurrence. The laparoscopic approach is the preferred technique in hemodynamically stable patients without significant comorbidities because it facilitates early diagnosis of small diaphragmatic injuries from traumatic wounds in the thoraco-abdominal area and reduces postoperative complications. Open surgery should be reserved for situations when skills and equipment for laparoscopy are not available, where exploratory laparotomy is needed, or if the patient is hemodynamically unstable. Damage Control Surgery is an option in the management of critical and unstable patients.

CONCLUSIONS

Complicated diaphragmatic hernia is a rare life-threatening condition. CT scan of the chest and abdomen is the gold standard for diagnosing the diaphragmatic hernia. Laparoscopic repair is the best treatment option for stable patients with complicated diaphragmatic hernias. Open repair is considered necessary in majority of unstable patients in whom Damage Control Surgery can be life-saving.

ECLAPTE: Effective Closure of LAParoTomy in Emergency-2023 World Society of Emergency Surgery guidelines for the closure of laparotomy in emergency settings

Laparotomy incisions provide easy and rapid access to the peritoneal cavity in case of emergency surgery. Incisional hernia (IH) is a late manifestation of the failure of abdominal wall closure and represents frequent complication of any abdominal incision: IHs can cause pain and discomfort to the patients but also clinical serious sequelae like bowel obstruction, incarceration, strangulation, and necessity of reoperation. Previous guidelines and indications in the literature consider elective settings and evidence about laparotomy closure in emergency settings is lacking. This paper aims to present the World Society of Emergency Surgery (WSES) project called ECLAPTE (Effective Closure of LAParoTomy in Emergency): the final manuscript includes guidelines on the closure of emergency laparotomy.

Anti-Factor Xa Monitoring of Enoxaparin Thromboembolism Prophylaxis in Emergency General Surgery Patients

BACKGROUND

Rates of venous thromboembolism (VTE) remain high in emergency general surgery (EGS) patients despite chemical VTE prophylaxis. Emerging literature supports anti-factor Xa (AFXa) monitoring for patients on enoxaparin (LMWH), though a significant knowledge gap remains regarding the optimal dosing and monitoring in EGS patients. We hypothesize that standard dose VTE prophylaxis regimens provide inadequate VTE prophylaxis in EGS patients.

STUDY DESIGN

A prospective cohort study of all adult EGS patients at a single institution between August 2021-February 2022 receiving standard dose LMWH for VTE prophylaxis was performed. AFXa levels were obtained 4-hours following the third dose of enoxaparin with a target range of 0.3-0.5 IU/mL. Adjustment to dosing and repeat AFXa measurement after the adjusted 3 rd dose was obtained.

RESULTS

A total of 81 patients underwent AFXa monitoring, the majority (75%) of whom were started on 40 mg LMWH daily. Initial peak AFXa measurement was low in 87.7% of patients (mean 0.16 IU/mL). Of patients who had an initial low AFXa, remained admitted, and underwent dosing adjustment and AFXa reassessment (27%), the majority were adjusted to either 30mg or 40mg LMWH twice daily (23.7% and 55%, respectively), with 82% of patients remaining low. There were no significant differences in demographics or body mass index between those with low vs. adequate AFXa levels at either initial or subsequent measurement.

CONCLUSION

Standard LMWH dosing provides inadequate AFXa inhibition for adequate VTE prophylaxis. These findings highlight the importance of ongoing AFXa monitoring and the need to establish clinical protocols to improve VTE prophylaxis in EGS patients.

Risk factors for pressure injury development in patients with spinal cord injury beyond index hospitalization: an analysis of violent mechanism of injury and socioeconomic disparity

INTRODUCTION

PIs are very common in those with SCI and pose a significant health and economic burden. Optimal prevention strategies require rapid identification of high-risk populations.

OBJECTIVE

The authors examined risk factors for PI in persons with traumatic SCI, focusing on mechanism of injury and sociodemographic variables.

MATERIALS AND METHODS

Patients aged 18 years or older at the authors' institution who had a traumatic SCI between January 1, 2002, and December 31, 2018 were included. Descriptive statistics and logistic regression analyses were conducted.

RESULTS

Of 448 patients, 94 patients (21%) had a violent SCI and 163 patients (36%) developed PIs. Violent mechanism of SCI was a significant predictor of a single (56% vs 31%; P <.001) or multiple PIs (83% vs 61%; P <.01), flap coverage (26% vs 17%; P <.05), and higher median stage PI (stage 4 vs stage 3, P <.05). Male sex (OR = 2.08; P <.05), complete SCI (OR = 5.51; P <.001), and violent mechanism of SCI (OR = 2.36; P <.01) were significant predictors on multivariate analysis. Increasing age at the time of SCI (OR = 1.01; P <.05) and unmarried marital status (OR = 1.77; P <.01) were predictive on univariate analysis.

CONCLUSIONS

Patients of male sex, complete SCI, and violent mechanism of SCI may be at higher risk of PI development and would benefit from more intensive prevention initiatives.

Comprehensive Framework of Firearm Violence Survivor Care: A Review

Importance

Firearm violence is a public health crisis placing significant burden on individuals, communities, and health care systems. After firearm injury, there is increased risk of poor health, disability, and psychopathology. The newest 2022 guidelines from the American College of Surgeons Committee on Trauma require that all trauma centers screen for risk of psychopathology and provide referral to intervention. Yet, implementing these guidelines in ways that are responsive to the unique needs of communities and specific patient populations, such as after firearm violence, is challenging.

Observations

The current review highlights important considerations and presents a model for trauma centers to provide comprehensive care to survivors of firearm injury. This model highlights the need to enhance standard practice to provide patient-centered, trauma-informed care, as well as integrate inpatient and outpatient psychological services to address psychosocial needs. Further, incorporation of violence prevention programming better addresses firearm injury as a public health concern.

Conclusions and Relevance

Using research to guide a framework for trauma centers in comprehensive care after firearm violence, we can prevent complications to physical and psychological recovery for this population. Health systems must acknowledge the socioecological context of firearm violence and provide more comprehensive care in the hospital and after discharge, to improve long-term recovery and serve as a means of tertiary prevention of firearm violence.

The LIFE TRIAD of emergency general surgery

Emergency General Surgery (EGS) was identified as multidisciplinary surgery performed for traumatic and non-traumatic acute conditions during the same admission in the hospital by general emergency surgeons and other specialists. It is the most diffused surgical discipline in the world. To live and grow strong EGS necessitates three fundamental parts: emergency and elective continuous surgical practice, evidence generation through clinical registries and data accrual, and indications and guidelines production: the LIFE TRIAD.

Need for Emergent Intervention within 6 Hours: A Novel Prediction Model for Hospital Trauma Triage

Objective: A tiered trauma team activation system allocates resources proportional to patients' needs based upon injury burden. Previous trauma hospital-triage models are limited to predicting Injury Severity Score which is based on > 10% all-cause in-hospital mortality, rather than need for emergent intervention within 6 hours (NEI-6). Our aim was to develop a novel prediction model for hospital-triage that utilizes criteria available to the EMS provider to predict NEI-6 and the need for a trauma team activation.Methods: A regional trauma quality collaborative was used to identify all trauma patients ≥ 16 years from the American College of Surgeons-Committee on Trauma verified Level 1 and 2 trauma centers. Logistic regression and random forest were used to construct two predictive models for NEI-6 based on clinically relevant variables. Restricted cubic splines were used to model nonlinear predictors. The accuracy of the prediction model was assessed in terms of discrimination.Results: Using data from 12,624 patients for the training dataset (62.6% male; median age 61 years; median ISS 9) and 9,445 patients for the validation dataset (62.6% male; median age 59 years; median ISS 9), the following significant predictors were selected for the prediction models: age, gender, field GCS, vital signs, intentionality, and mechanism of injury. The final boosted tree model showed an AUC of 0.85 in the validation cohort for predicting NEI-6.Conclusions: The NEI-6 trauma triage prediction model used prehospital metrics to predict need for highest level of trauma activation. Prehospital prediction of major trauma may reduce undertriage mortality and improve resource utilization.

Optimal timing of venous thromboembolic chemoprophylaxis initiation following blunt solid organ injury: meta-analysis and systematic review

PURPOSE

The need to prevent venous thromboembolism (VTE) following blunt solid organ injury must be balanced against the concern for exacerbation of hemorrhage. The optimal timing for initiation of VTE chemoprophylaxis is not known. The objective was to determine the safety and efficacy of early (≤ 48 h) VTE chemoprophylaxis initiation following blunt solid organ injury.

METHODS

An electronic search was performed of medical libraries for English language studies on timing of VTE chemoprophylaxis initiation following blunt solid organ injury published from inception to April 2020. Included studies compared early (≤ 48 h) versus late (> 48 h) initiation of VTE chemoprophylaxis in adults with blunt splenic, liver, and/or kidney injury. Estimates were pooled using random-effects meta-analysis. Odds ratios were utilized to quantify differences in failure of nonoperative management, need for blood transfusion and rates of VTE.

RESULTS

The search identified 2,111 studies. Of these, ten studies comprising 14,675 patients were included. All studies were non-randomized and only one was prospective. The overall odds of failure of nonoperative management were no different between early and late groups, OR 1.09 (95%CI 0.92-1.29). Similarly, there was no difference in the need for blood transfusion either during overall hospital stay, OR 0.91 (95%CI 0.70-1.18), or post prophylaxis initiation, OR 1.23 (95%CI 0.55-2.73). There were significantly lower odds of VTE when patients received early VTE chemoprophylaxis, OR 0.51 (95%CI 0.33-0.81).

CONCLUSIONS

Patients undergoing nonoperative management for blunt solid organ injury can be safely and effectively prescribed early VTE chemoprophylaxis. This results in significantly lower VTE rates without demonstrable harm.

A national study defining 1.0 full-time employment in trauma and acute care surgery

BACKGROUND

Trauma and acute care surgery (ACS) staffing models vary widely across the United States, resulting in large discrepancies in staffing, compensation, schedule, and clinical/nonclinical expectations. An urgent need exists to define clinical, academic, and schedule expectations for a full-time employment (FTE) of a trauma and ACS surgeon in the United States.

METHODS

A survey was distributed to departmental leaders at Levels I, II, III trauma centers across the United States regarding current workload. Variables concerning the responsibilities of surgeons, compensation models, and clinical expectations were collected. This was followed by virtual semistructured interviews of agreeable respondents. A thematic analysis was used to describe current staffing challenges and "ideal" staffing and compensation models of trauma centers.

RESULTS

Sixty-eight of 483 division chiefs/medical directors responded (14%), the majority (66%) representing Level I centers. There were differences in clinical responsibilities, elective surgery coverage as well as number of and reimbursement for call. The median description of an FTE was 26 weeks (interquartile range, 13 weeks) with a median of 8 (interquartile range, 8) 12-hour call shifts per month. Level III centers were more likely to perform elective surgery and covered more call shifts, typically from home. In our qualitative interviews, we identified numerous themes, including inconsistent models and staffing of services, surgeon-administration conflict and elective surgery driven by productivity and desire.

CONCLUSION

Defining the workload of a full-time trauma and ACS surgeon is nuanced and requires consideration of local volume, acuity and culture. Between the quantitative and qualitative analysis, a reasonable workload for a 1.0 FTE acute care surgeon at a Level I center is 24 to 28 service weeks per year and four to five in-house calls per month. Nighttime and daytime staffing needs can be divergent and may lead to conflict with administration. Future research should consider the individual surgeon's perspective on the definition of an FTE.

LEVEL OF EVIDENCE

Prognostic and epidemiological, Level III.

Evaluation and management of traumatic pneumothorax: A Western Trauma Association critical decisions algorithm

ABSTRACT

This is a recommended algorithm of the Western Trauma Association for the management of a traumatic pneumothorax. The current algorithm and recommendations are based on available published prospective cohort, observational, and retrospective studies and the expert opinion of the Western Trauma Association members. The algorithm and accompanying text represents a safe and reasonable approach to this common problem. We recognize that there may be variability in decision making, local resources, institutional consensus, and patient-specific factors that may require deviation from the algorithm presented. This annotated algorithm is meant to serve as a basis from which protocols at individual institutions can be developed or serve as a quick bedside reference for clinicians.

LEVEL OF EVIDENCE

Consensus algorithm from the Western Trauma Association, Level V.

The small (14 Fr) percutaneous catheter (P-CAT) versus large (28-32 Fr) open chest tube for traumatic hemothorax: A multicenter randomized clinical trial

INTRODUCTION

The traditional treatment of traumatic hemothorax (HTX) has been an insertion of a large-bore 36- to 40-Fr chest tube. Our previous single-center randomized controlled trial (RCT) had shown that 14-Fr percutaneous catheters (PCs) (pigtail) were equally as effective as chest tube. We performed a multicenter RCT, hypothesizing that PCs are as equally effective as chest tubes in the management of patients with traumatic HTX (NCT03546764).

METHODS

We performed a multi-institution prospective RCT comparing 14-Fr PCs with 28- to 32-Fr chest tubes in the management of patients with traumatic HTX from July 2015 to September 2020. We excluded patients who were in extremis and required emergent tube placement and those who refused to participate. The primary outcome was failure rate, defined as a retained HTX requiring a second intervention. Secondary outcomes included daily drainage output, tube days, intensive care unit and hospital length of stay, and insertion perception experience (IPE) score on a scale of 1 to 5 (1, tolerable experience; 5, worst experience). Unpaired Student's t test, χ2, and Wilcoxon rank sum test were used with significance set at p < 0.05.

RESULTS

After exclusion, 119 patients participated in the trial, 56 randomized to PCs and 63 to chest tubes. Baseline characteristics between the two groups were similar. The primary outcome, failure rate, was similar between the two groups (11% PCs vs. 13% chest tubes, p = 0.74). All other secondary outcomes were also similar, except PC patients reported lower IPE scores (median, 1: "I can tolerate it"; interquartile range, 1-2) than chest tube patients (median, 3: "It was a bad experience"; interquartile range, 2-5; p < 0.001).

CONCLUSION

Small caliber 14-Fr PCs are equally as effective as 28- to 32-Fr chest tubes in their ability to drain traumatic HTX with no difference in complications. Patients reported better IPE scores with PCs over chest tubes, suggesting that PCs are better tolerated.

LEVEL OF EVIDENCE

Therapeutic, level II.

Bowel Ischemia Score Predicts Early Operation in Patients With Adhesive Small Bowel Obstruction

BACKGROUND

Nonoperative management of adhesive small bowel obstruction (SBO) is successful in up to 80% of patients. Current recommendations advocate for computed tomography (CT) scan in all patients with SBO to supplement surgical decision-making. The hypothesis of this study was that cumulative findings on CT would predict the need for operative intervention in the setting of SBO.

METHODS

This is an analysis of a retrospectively and prospectively collected adhesive SBO database over a 6-year period. A Bowel Ischemia Score (BIS) was developed based on the Eastern Association for the Surgery of Trauma guidelines of CT findings suggestive of bowel ischemia. One point was assigned for each of the six variables. Early operation was defined as surgery within 6 hours of CT scan.

RESULTS

Of the 275 patients in the database, 249 (90.5%) underwent CT scan. The operative rate was 28.3% with a median time from CT to operation of 21 hours (Interquartile range 5.2-59.2 hours). Most patients (166/217, 76.4%) with a BIS of 0 or 1 were successfully managed nonoperatively, whereas the majority of those with a BIS of 3 required operative intervention (5/6, 83.3%). The discrimination (area under the receiver operating characteristic curve) of BIS for early surgery, any operative intervention, and small bowel resection were 0.83, 0.72, and 0.61, respectively.

CONCLUSION

The cumulative signs of bowel ischemia on CT scan represented by BIS, rather than the presence or absence of any one finding, correlate with the need for early operative intervention.

Phenobarbital for Acute Alcohol Withdrawal Management in Surgical Trauma Patients-A Retrospective Comparison Study

BACKGROUND

Alcohol withdrawal syndrome (AWS) in surgical trauma patients is associated with significant morbidity and mortality. Benzodiazepines, commonly used for withdrawal management, pose unique challenges in this population given the high prevalence of head trauma and delirium. Phenobarbital is an antiepileptic drug that offers a viable alternative to benzodiazepines for AWS treatment.

METHODS

This is a retrospective chart review of patients with active alcohol use disorder who presented to a level 1 trauma center over a 4-year period and required medication-assisted management for AWS. The primary outcome variable examined was the development of AWS and associated complications. Additional outcomes measured included hospital length of stay, mortality, and medication-related adverse events.

RESULTS

Of the 85 patients in the study sample, 52 received a fixed-dose benzodiazepine-based protocol and 33 received phenobarbital-based protocol. In the benzodiazepine-based protocol group, 25 patients (48.2%) developed AWD and 38 (73.1%) developed uncomplicated AWS, as compared to 0 patients in the phenobarbital-based protocol (P = 0.0001). There were 10 (19.2%) patients with medication adverse side effects in the benzodiazepine-based protocol group versus 0 patients in the phenobarbital-based protocol group. There were no statically significant differences between the 2 groups as pertains to rates of other AWS-related complications, patient mortality, or length of stay.

CONCLUSION

The use of a phenobarbital-based protocol in trauma patients with underlying active alcohol use disorder resulted in a statistically significant decrease in the incidence of AWD and uncomplicated AWS secondary to AWS when compared to patients treated with a fixed-dose benzodiazepine-based protocol.

Early Enteral Nutrition Adequacy Mitigates the Neutrophil-Lymphocyte Ratio Improving Clinical Outcomes in Critically Ill Surgical Patients

BACKGROUND

Neutrophil-lymphocyte ratio (NLR) is a measure of host inflammatory response; a higher NLR is associated with worse clinical outcomes. Enteral nutrition (EN) may mitigate inflammation through interaction with gut-associated lymphoid tissue. We hypothesized that early EN adequacy in critically ill surgical patients is associated with lower NLR and better clinical outcomes.

METHODS

In this retrospective study, we analyzed data from adult surgical intensive care unit (ICU) patients receiving EN. NLR at baseline ICU admission (NLR-B), NLR after 3-5 days of EN (F-NLR), nutrition adequacy, caloric deficit (CD), protein deficit (PD), hospital length of stay (LOS), ICU LOS, 28-day ventilator-free days (28-VFD), and in-hospital mortality were collected. Tertiles groups were created for NLR, F-NLR, CD, and PD; the highest (H) and lowest (L) tertiles were compared. Regression analyses were performed to control for effect of age, gender, APACHE II, and NLR.

RESULTS

Subjects in the L-CD group had lower median F-NLR (7 [range, 5-11] vs 10 [7-22], P = 0.005) and shorter ICU LOS (9 [6-16]) vs 16 [9-32] days; P = 0.006). The L-NLR group had shorter hospital LOS (18 [10-31] vs 22 [15-38] days, P = 0.023), greater 28-VFD (23 [18-25] vs 19 [11-22] days, P = 0.005), and lower in-hospital mortality (13% vs 41%, P = 0.002).

CONCLUSION

In critically ill surgical patients, early enteral caloric adequacy is associated with less inflammation and improved clinical outcomes.

High-Fidelity Emergency Department Thoracotomy Simulator With Beating-Heart Technology and OSATS Tool Improves Trainee Confidence and Distinguishes Level of Skill

OBJECTIVE

Resuscitative Thoracotomy or Emergency Department Thoracotomy (EDT) is a time-sensitive and potentially life-saving procedure. Yet, trainee experience with this procedure is often limited in both clinical and simulation settings. We sought to develop a high-fidelity EDT simulation module and assessment tool to facilitate trainee education.

DESIGN

Using the Kern model for curricular development, a group of expert trauma surgeons identified EDT as a high-stakes, low-frequency procedure. Task analysis identified 5 key steps of EDT: (1) opening chest/rib spreader utilization; (2) pericardiotomy/cardiac repair; (3) open cardiac massage; (4) clamping aorta; and (5) control of pulmonary hilum. A high-fidelity simulator with beating-heart technology was built. The previously validated Objective Structured Assessment of Technical Skills (OSATS) was adapted to create the "EDT-OSATS" which assessed performance along several domains: (1) Surgical technique (key steps); (2) general skills; and (3) global rating. A pilot test was performed to compare board-certified trauma surgeons (i.e., Experts) with categorical general surgery interns (i.e., Novices). Each subject received preparatory materials, completed a presimulation quiz, performed a videotaped procedure on the EDT simulator, and completed a postmodule survey. Two independent raters scored performances using the EDT-OSATS. Groups were compared in descriptive and unadjusted analyses. We hypothesized that our EDT simulation module would distinguish between expert vs novice performance and improve trainee confidence.

SETTING

Simulation laboratory at Massachusetts General Hospital in Boston, MA.

PARTICIPANTS

Trauma surgeons (Experts, n = 6) and categorical general surgery interns (Novices, n = 8).

RESULTS

Experts scored significantly higher than Novices on nearly all components of the EDT-OSATS, including: (1) surgical technique: pericardiotomy (4.2 vs 3.4, p = 0.040), cardiac massage (3.6 vs 2.4, p = 0.028), clamping aorta (4.1 vs 3.3, p = 0.035), control of pulmonary hilum (4.8 vs 3.4, p < 0.001); (2) general skills: time/motion (4.1 vs 2.9, p = 0.011), knowledge and handling of instruments (4.3 vs 3.1, p = 0.004), and (3) global rating (3.9 vs 2.9, p = 0.026). There was no statistical difference between groups on opening chest/rib spreader utilization (3.8 vs 3.3, p = 0.352) or procedure time (204sec vs 227sec, p = 0.401), though Experts scored numerically higher than Novices on every measure. Novices reported significantly increased confidence after the simulation (3.1 vs 1.4, p = 0.001). Ninety-three percent (13/14) of participants found the simulator realistic.

CONCLUSIONS

Our novel high-fidelity beating-heart EDT simulator is realistic and improves trainee confidence in this low-frequency, high-stakes emergency procedure. The EDT-OSATS tool differentiates between performances of experienced surgeons vs novice trainees on the beating-heart simulator. This training module and accompanying assessment instrument hold promise as a learning tool for clinicians who may perform emergency department thoracotomy.

Derivation and validation of a practical Bedside Score for the diagnosis of cholecystitis

OBJECTIVE

We sought to develop a practical Bedside Score for the diagnosis of cholecystitis and test its accuracy against the Tokyo Guidelines (TG13).

METHODS

We conducted a retrospective study of 438 patients undergoing urban, academic Emergency Department (ED) evaluation of RUQ pain. Symptoms, physical signs, ultrasound signs, and labs were scoring system candidates. A random split-sample approach was used to develop and validate a new clinical score. Multivariable regression analysis using development data was conducted to identify predictors of cholecystitis. Cutoff values were chosen to ensure positive/negative predictive values (PPV, NPV) of at least 0.95. The score was externally validated in 80 patients at a different hospital undergoing RUQ pain evaluation.

RESULTS

230 patients (53%) had cholecystitis. Five variables predicted cholecystitis and were included in the scores: gallstones, gallbladder thickening, clinical or ultrasonographic Murphy's sign, RUQ tenderness, and post-prandial symptoms. A clinical prediction score was developed. When dichotomized at 4, overall accuracy for acute cholecystitis was 90% for the development cohort, 82% and 86% for the internal and external validation cohorts; TG13 accuracy was 62%-79%.

CONCLUSIONS

A clinical prediction score for cholecystitis demonstrates accuracy equivalent to TG13. Use of this score may streamline work-up by decreasing the need for comprehensive ultrasound evaluation and CRP measurement and may shorten ED length of stay.

Splenic trauma: WSES classification and guidelines for adult and pediatric patients

Spleen injuries are among the most frequent trauma-related injuries. At present, they are classified according to the anatomy of the injury. The optimal treatment strategy, however, should keep into consideration the hemodynamic status, the anatomic derangement, and the associated injuries. The management of splenic trauma patients aims to restore the homeostasis and the normal physiopathology especially considering the modern tools for bleeding management. Thus, the management of splenic trauma should be ultimately multidisciplinary and based on the physiology of the patient, the anatomy of the injury, and the associated lesions. Lastly, as the management of adults and children must be different, children should always be treated in dedicated pediatric trauma centers. In fact, the vast majority of pediatric patients with blunt splenic trauma can be managed non-operatively. This paper presents the World Society of Emergency Surgery (WSES) classification of splenic trauma and the management guidelines.

Rib fixation: Who, What, When?

Rib fractures are among the most common traumatic injury found in ∼20% of all patients who suffer thoracic trauma. The majority of these are a result of a blunt mechanism and are often associated with other traumatic injuries. The most common associated injury is lung contusion. Rib fractures impart an increased morbidity and mortality with the highest mortality associated with a flail chest in the elderly population. Flail chest is defined radiographically as 3 or more consecutive ribs fractured in 2 or more places. This often translates to a clinical flail which is associated with paradoxical chest wall movement during respiratory cycles. The mainstay of treatment has been pain control and respiratory support with positive pressure ventilation. However, over the past 2 decades, there has been mounting evidence to suggest that open reduction and internal fixation of ribs benefits patients. The indications remain confined to the most severely injured patients with flail chest or chronic non-unions; however, there remains debate whether or not less severely injured patients would benefit as well. This article will review the current evidence and provide proposed indications based on available evidence and current expert opinion.

Computed Tomography Is More Sensitive than Ultrasound for the Diagnosis of Acute Cholecystitis

BACKGROUND

Ultrasound (US) is the first-line diagnostic study for evaluating gallstone disease and is considered the test of choice for diagnosing acute cholecystitis (AC). However, computed tomography (CT) is used widely for the evaluation of abdominal pain and is often obtained as a first abdominal imaging test, particularly in cases in which typical clinical signs of AC are absent or other possible diagnoses are being considered. We hypothesized that CT is more sensitive than US for diagnosing AC.

METHODS

A prospective registry of all urgent cholecystectomies performed by our acute care surgery service between June 2008 and January 2014 was searched for cases of AC. The final diagnosis was based on operative findings and pathology. Patients were classified into two groups according to pre-operative radiographic work-up: US only or CT and US. The US group was compared with the CT and US group with respect to clinical and demographic characteristics. For patients undergoing both tests the sensitivity of the two tests was compared.

RESULTS

One hundred one patients with AC underwent both US and CT. Computed tomography was more sensitive than US for the diagnosis of AC (92% versus 79%, p=0.015). Ultrasound was more sensitive than CT for identification of cholelithiasis (87% versus 60%, p<0.01). Patients undergoing both tests prior to surgery were more likely to be older, male, have medical comorbidities, and lack typical clinical signs of AC.

CONCLUSIONS

Computed tomography is more sensitive than US for the diagnosis of AC and is most often used in patients without typical clinical signs of AC.

Preoperative evaluation of penetrating esophageal trauma in the current era: An analysis of the National Trauma Data Bank

Background:

Preoperative diagnostic evaluation (PDE) of penetrating esophageal injury (PeEsIn) can delay treatment and increase morbidity. We sought to study the relationship among PDE, delay in definitive treatment, and patient mortality in PeEsIn.

Materials and Methods:

The 2008-2010 National Trauma Data Banks were queried for PeEsIn. Exclusion criteria were death within 1 day of injury, and missing data about survival to discharge or operative intervention. Data extracted included demographics, vital signs, injury severity, diagnostic procedures (endoscopy, computed tomography, and fluoroscopy), time to procedures and/or operation, hospital-free days, and mortality.

Results:

Of 280 patients, 75 underwent PDE and 205 did not. There were no significant differences in baseline demographics, vital signs or injury severity between the two groups. The median time to the first operation was shorter in the nonPDE cohort compared to the PDE cohort (2 vs. 3 h; P = 0.018). Median hospital-free days at day 60 were significantly less in nonPDE (42 days, interquartile range ([IQR] = [28, 50]) versus PDE patients (47 days, IQR = [38, 51]) (P = 0.007). Mortality was not statistically different.

Conclusions:

PDE in PeEsIn slightly delays the time to operation without worsening mortality, and is a predictor of more hospital-free days.

Opening Pandora's box: understanding the nature, patterns, and 30-day outcomes of intraoperative adverse events

BACKGROUND

Little evidence exists regarding the characteristics of intraoperative adverse events (iAEs).

METHODS

Administrative data, the American College of Surgeons - National Surgical Quality Improvement Project, and systematic review of operative reports were used to confirm iAEs in abdominal surgery patients. Standard American College of Surgeons - National Surgical Quality Improvement Project data were supplemented with variables including injury type/organ, phase of operation, adhesions, repair type, and intraoperative consultations.

RESULTS

Two hundred twenty-seven iAEs (187 patients) were confirmed in 9,292 patients. Most common injuries were enterotomies during intestinal surgery (68%) and vessel injuries during hepatopancreaticobiliary surgery (61%); 108 iAEs (48%) specifically occurred during adhesiolysis. A third of the iAEs required organ/tissue resection or complex reconstruction. Because of iAEs, 20 intraoperative consults (11%) were requested and 9 of the 66 (16%) laparoscopic cases were converted to open. Thirty-day mortality and morbidity were 6% and 58%, respectively. The complications included perioperative transfusions (36%), surgical site infection (19%), systemic sepsis (13%), and failure to wean off the ventilator (12%).

CONCLUSIONS

iAEs commonly occur in reoperative cases requiring lysis of adhesions and possibly lead to increased patient morbidity. Understanding iAEs is essential to prevent their occurrence and mitigate their adverse effects.

MDCT quantification is the dominant parameter in decision-making regarding chest tube drainage for stable patients with traumatic pneumothorax

It is commonly believed that the size of a pneumothorax is an important determinant of treatment decision, in particular regarding whether chest tube drainage (CTD) is required. However, the volumetric quantification of pneumothoraces has not routinely been performed in clinics. In this paper, we introduced an automated computer-aided volumetry (CAV) scheme for quantification of volume of pneumothoraces in chest multi-detect CT (MDCT) images. Moreover, we investigated the impact of accurate volume of pneumothoraces in the improvement of the performance in decision-making regarding CTD in the management of traumatic pneumothoraces. For this purpose, an occurrence frequency map was calculated for quantitative analysis of the importance of each clinical parameter in the decision-making regarding CTD by a computer simulation of decision-making using a genetic algorithm (GA) and a support vector machine (SVM). A total of 14 clinical parameters, including volume of pneumothorax calculated by our CAV scheme, was collected as parameters available for decision-making. The results showed that volume was the dominant parameter in decision-making regarding CTD, with an occurrence frequency value of 1.00. The results also indicated that the inclusion of volume provided the best performance that was statistically significant compared to the other tests in which volume was excluded from the clinical parameters. This study provides the scientific evidence for the application of CAV scheme in MDCT volumetric quantification of pneumothoraces in the management of clinically stable chest trauma patients with traumatic pneumothorax.

Successful selective nonoperative management of abdominal gunshot wounds despite low penetrating trauma volumes

OBJECTIVE

To determine whether selective nonoperative management of abdominal gunshot wounds (AGSW) is safe in trauma centers with a low volume of penetrating trauma.

DESIGN

Retrospective study.

SETTING

Academic level 1 trauma center with approximately 10% penetrating trauma.

PATIENTS

All patients with anterior and posterior AGSW (January 1, 1999, through December 31, 2009), excluding tangential injuries, transfers, and deaths in the emergency department. Patients with hemodynamic instability or peritonitis received an urgent laparotomy. The remaining patients had selective nonoperative management. A delayed laparotomy was offered for worsening symptoms or worrisome computed tomography findings.

MAIN OUTCOME MEASURES

Hospital stay, complications, and mortality.

RESULTS

Of 125 AGSW patients, 38 (30%) were initially managed by selective nonoperative management (25 of 99 anterior and 13 of 26 posterior AGSW patients). Seven selective nonoperative management patients received delayed laparotomy as late as 11 hours after admission. At the end, 30 of the 125 patients (24%) were successfully managed without an operation (20 of 99 anterior and 10 of 26 posterior AGSW patients). There were no predictors of delayed laparotomy and no complications or mortality attributed to it. Ten patients (8%) had a nontherapeutic laparotomy, and 3 of them developed complications.

CONCLUSIONS

Selective nonoperative management of AGSW is feasible and safe in trauma centers with low penetrating trauma volumes. Nearly 1 in 4 AGSW patients does not need a laparotomy, and nontherapeutic laparotomies are associated with complications. The volume of AGSW per se should not be an excuse for routine laparotomies. These data become particularly important because penetrating trauma volumes are decreasing around the country.

Ignoring non-specific abdominal pain in emergency department patients may be related to decreased quality of life. A follow up of an underestimated problem

QUESTIONS UNDER STUDY

Patients suffering from chronic pain have a high prevalence of depression, resulting in a significant impact on overall quality of life. Our aim was to investigate how long term acute non-specific abdominal pain (NSAP) affected overall physical and mental well-being in patients admitted to our emergency department (ED).

METHODS

All patients discharged from the ED with NSAP between 06/2007 and 06/2008 were included for follow up. Current health and well-being was evaluated using the SF-36® health questionnaire. Ordinal linear regression models were chosen to separately assess variables influencing SF-36® outcome, with adjustment for age and gender. Results were expressed as differences of means with corresponding 95% confidence intervals and p-values.

RESULTS

Of the 200 patients included (57% female, mean age 33 years), 53 (26.5%) still suffered from NSAP after a 12.5-month mean follow up. Patients with persistent NSAP suffered more from chronic pain (26.4%) or known psychiatric illnesses (15.1%) than unaffected patients (p<0.001 and p=0.028). Mental (MCS) and physical component scores (PCS) were significantly worse in patients suffering from persistent NSAP, even when adjusted for confounding factors including chronic pain syndromes, pre-existing psychiatric illnesses, other concomitant comorbidities and previous abdominal surgery (p<0.001 for both scores). Other risk factors included chronic pain syndromes, pre-existing psychiatric illnesses, other concomitant comorbidities and previous abdominal surgery.

CONCLUSIONS

NSAP persistence may be associated with a decreased quality of life. Emphasis should be put on providing early counselling and support, with the aim of minimising the long term detrimental side effects of NSAP.

Histone deacetylase inhibitors prevent apoptosis following lethal hemorrhagic shock in rodent kidney cells

BACKGROUND

We have previously demonstrated that treatment with histone deacetylase inhibitors (HDACI), such as valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA), can improve survival after hemorrhagic shock in animal models. Hemorrhage results in hypoacetylation of proteins which is reversed by HDACI. These agents are known to acetylate insulin receptor substrate-I (IRS-I), which in turn activates the Akt survival pathway. This study investigated whether HDACI exert their beneficial effects through the Akt survival pathway.

METHODS

Wistar-Kyoto rats (N=21) underwent hemorrhage (60% blood loss) and were randomized into 3 groups; no resuscitation (NR), and treatment with VPA or SAHA. Kidneys were harvested at 1, 6, and 24h after HDACI treatment and analyzed for acetylated histone 3 at lysine 9 residue (Ac-H3K9), phosphorylated Akt (phospho-Akt), BAD and Bcl-2 proteins.

RESULTS

Hemorrhaged animals were in severe shock, with mean arterial pressures of 25-30mmHg and lactic acid 7-9mg/ml. Only animals treated with VPA and SAHA survived to the 6- and 24-h timepoints. Treatment with HDACI produced a biologic effect on rat kidney cells inducing acetylation of histone H3K9, which peaked after 1h of treatment, and was statistically significant in the VPA group (p=0.01) compared to NR. Phospho-Akt protein increased in the VPA group with a reciprocal decrease in the pro-apoptotic BAD protein in both groups which was statistically significant in the VPA group after 1h (p=0.007) and 24h (p=0.006) of treatment and in the SAHA group after 24h of treatment (p=0.028). Anti-apoptotic Bcl-2 protein markedly increased after 6 (p=0.04) and 24h (p=0.014) of VPA treatment. Bcl-2 also increased in the SAHA group, but failed to reach statistical significance.

CONCLUSION

Treatment with HDACI increases phosphorylation of Akt with a subsequent decrease in the pro-apoptotic BAD protein. The above mechanism facilitates the action of anti-apoptotic protein Bcl-2. HDACI protect kidney cells subjected to hemorrhagic shock in rodents through the Akt survival pathway.

Diagnosis of necrotizing soft tissue infections by computed tomography

HYPOTHESIS

In contrast to previous beliefs, we hypothesize that computed tomography (CT) scanning is sensitive and specific for the diagnosis of necrotizing soft tissue infections (NSTIs).

DESIGN

Retrospective and prospective case series.

SETTING

Academic medical center.

PATIENTS

Patients who were clinically suspected of having NSTIs from January 1, 2003, through April 30, 2009, and who underwent imaging with a 16- or 64-section helical CT scanner were studied. The CT result was considered positive if inflamed and necrotic tissue with or without gas or fluid collections across tissue planes was found. The disease (NSTI) was considered present if surgical exploration revealed elements of infection and necrosis of the soft tissues and pathological analysis confirmed the findings. The disease was considered absent if surgical exploration and pathological analysis failed to identify any of these findings or the patient was successfully treated without surgical exploration.

MAIN OUTCOME MEASURES

Sensitivity and specificity of CT for diagnosing NSTI.

RESULTS

Of 67 patients with study inclusion criteria, 58 underwent surgical exploration, and NSTI was confirmed in 25 (43%). The remaining 42 patients had either nonnecrotizing infections during surgical exploration (n = 33) or were treated nonoperatively with successful resolution of the symptoms (n = 9). The sensitivity of CT to identify NSTI was 100%, specificity was 81%, positive predictive value was 76%, and negative predictive value was 100%. No differences were found in demographics, white blood cell count on admission, symptoms, or site of infection between those with a false- or true-positive CT result.

CONCLUSIONS

A negative CT result reliably excludes the diagnosis of NSTI. A positive CT result correctly identifies the disease with a high likelihood.

Pulmonary embolism and deep venous thrombosis in trauma: are they related?

HYPOTHESIS

Pulmonary embolism (PE) and deep venous thrombosis (DVT) in trauma are related.

DESIGN

Retrospective review of medical records.

SETTING

Academic level I trauma center.

PATIENTS

Trauma patients who underwent computed tomographic pulmonary angiography (CTPA) with computed tomographic venography (CTV) of the pelvic and proximal lower extremity veins over a 3-year period (January 1, 2004, to December 31, 2006) were reviewed. Data on demographics, injury type and severity, imaging findings, hospital length of stay, and mortality were collected.

MAIN OUTCOME MEASURES

Pulmonary embolism and DVT.

RESULTS

Among 247 trauma patients undergoing CTPA/CTV, PE was diagnosed in 46 (19%) and DVT in 18 (7%). Eighteen PEs were central (main or lobar pulmonary arteries), and 28 PEs were peripheral (segmental or subsegmental branches). Pulmonary embolism occurred within the first week of injury in two-thirds of patients. Seven patients with PE (4 femoral, 2 popliteal, and 1 iliac) had DVT. Pulmonary embolism was central in 5 patients and peripheral in 2 patients. No significant differences were noted in any of the examined variables between patients with PE having DVT and those not having DVT.

CONCLUSIONS

Few patients with PE have DVT of the pelvic or proximal lower extremity veins. Pulmonary embolism may not originate from these veins, as commonly believed, but instead may occur de novo in the lungs. These findings have implications for thromboprophylaxis and, particularly, the value of vena cava filters.

Abdominal insufflation for control of bleeding after severe splenic injury

BACKGROUND

To date, there is no rapid method to control intracavitary bleeding without an operation. Over 70% of trauma deaths from uncontrollable internal bleeding occur early after injury before an operation is feasible. Abdominal insufflation (AI) by carbon dioxide has been shown to reduce the rate of bleeding after intra-abdominal injury in pigs. The concept was proven in highly lethal models of severe vascular and liver injuries. Similar injuries in humans would result in immediate exsanguination and low likelihood for any intervention. We hypothesized that AI would similarly reduce bleeding in a model of moderate but persistent bleeding from a splenic injury. This model represents a clinically relevant scenario of continuous bleeding, which does not kill the patient immediately but may ultimately result in death if not managed early.

METHODS

A new model of splenic injury was applied on 19 pigs, randomized to standard resuscitation (SR, N = 10) or standard resuscitation with AI to 20 cm H2O (SRAI, N = 9). For 30 minutes, the pigs were bled and the hemodynamics recorded. At 30 minutes, the abdomen was opened and free blood was collected and measured. Outcomes were blood loss, mean arterial pressure, hemoglobin, lactate levels, and arterial blood gases at the end of the experiment.

RESULTS

All pigs survived to the end of the experiment. Blood loss was lower (1,114 +/- 486 mL vs. 666 +/- 323 mL, p = 0.03) and final mean arterial pressure higher (64 +/- 12 mm Hg vs. 54 +/- 8 mm Hg, p = 0.04) in SRAI when compared with those in SR animals. Heart rate, arterial blood gases, oxygen saturation, hemoglobin, and lactate levels were similar in the two groups, except there was a more acidotic pH among SRAI animals (7.27 +/- 0.06 vs. 7.47 +/- 0.21, p = 0.02).

CONCLUSIONS

AI is a novel method to control intra-abdominal bleeding temporarily. With proper portable instruments and first-responder training, this is a technique that can potentially be used in the field to save lives from intra-abdominal exsanguination.

Impact of resuscitation strategies on the acetylation status of cardiac histones in a swine model of hemorrhage

BACKGROUND

Chromatin remodeling through histone acetylation is a key control mechanism in gene transcription. We have shown previously that fluid resuscitation in rodents is coupled with highly structured post-translational modifications of cardiac histones. The current experiment was performed to validate this concept in a clinically relevant large animal model of hemorrhage and resuscitation, and to correlate the changes in histone acetylation with altered expression of immediate-early response genes.

STUDY DESIGN

Yorkshire swine (n=49, 7/group, weight=40-58kg) were subjected to combined uncontrolled and controlled hemorrhage (40% of estimated blood volume) and randomly assigned to the following resuscitation groups: (1) 0.9% saline (NS), (2) racemic lactated Ringer's (dl-LR), (3) l-isomer lactated Ringer's (l-LR), (4) Ketone Ringer's (KR), (5) 6% hetastarch in saline (Hespan). KR contained an equimolar substitution of lactate with beta-hydroxybutyrate. No hemorrhage (NH) and no resuscitation (NR) groups were included as controls. Cardiac protein was used in Western blotting to analyze total protein acetylation and histone acetylation specifically. Lysine residue-specific acetylation of histone subunits H3 and H4 was further evaluated. In addition, Chromatin Immunoprecipitation (ChIP) technique was used to separate the DNA bound to acetylated histones (H3 and H4 subunits), followed by measurement of genes that are altered by hemorrhage/resuscitation, including immediate-early response genes (c-fos and c-myc), and heat shock protein (HSP) 70.

RESULTS

The type of fluid used for resuscitation influenced the patterns of cardiac histone acetylation. Resuscitation with dl-LR and KR induced hyperacetylation on H3K9. KR resuscitation was also associated with increased acetylation on H3K14 and H4K5, and hypoacetylation on H3K18. The expression of genes was also fluid specific, with the largest number of changes following KR resuscitation (increased c-fos and c-myc, HSP 70 linked with H3; and increased c-myc linked with H4). Among the histone subunits studied, altered H3 acetylations were associated with the majority of changes in immediate-early gene expression.

CONCLUSIONS

Acetylation status of cardiac histones, affected by hemorrhage, is further modulated by resuscitation producing a fluid-specific code that is preserved in different species. Resuscitation with KR causes histone acetylation at the largest number of lysine sites (predominately H3 subunit), and has the most pronounced impact on the transcriptional regulation of selected (immediate-early response) genes.

Profound hypothermic cardiopulmonary bypass facilitates survival without a high complication rate in a swine model of complex vascular, splenic, and colon injuries

BACKGROUND

Induction of a profound hypothermia for emergency preservation and resuscitation in severe hemorrhagic shock can improve survival from lethal injuries, but the impact of hypothermia on bleeding and infectious complications has not been completely determined.

STUDY DESIGN

Uncontrolled hemorrhage was induced in 26 swine (95 to 135 lbs) by creating an iliac artery and vein injury, and 30 minutes later, by lacerating the descending thoracic aorta. Through a left thoracotomy approach, profound total body hypothermia (10 degrees C) was induced (2 degrees C/min) by infusing cold organ preservation solution into the aorta. The experimental groups were: vascular injuries alone (group 1, n=10), vascular and colon injuries (group 2, n=8), and vascular, colon, and splenic injuries (group 3, n=8). All injuries were repaired during 60 minutes of low-flow cardiopulmonary bypass (CPB) with hemodilution and profound hypothermia; then the animals were slowly rewarmed (0.5 degrees C/min) back to normothermia. Survivors were monitored for 6 weeks for postoperative bleeding, neurologic deficits, cognitive function (learning new skills), organ dysfunction, and septic complications.

RESULTS

Six-week survival rates were 90% in group 1, 87.5% in group 2, and 75% in group 3 (p > 0.05). One animal in each group died from acute cardiac failure during the early postoperative phase. Splenic salvage was possible in all animals, and none required complete splenectomy for hemorrhage control. All surviving animals were neurologically intact, displayed normal learning capacity, and had no longterm organ dysfunction. None of the animals had postoperative hemorrhage or experienced septic complications. One animal in group 3 died on the ninth postoperative day because of bowel obstruction (volvulus).

CONCLUSIONS

Induction of profound hypothermia can preserve the viability of key organs during repair of lethal injuries. This strategy can be used even in the presence of solid organ and bowel injuries to improve survival, without any considerable increase in postoperative complication rates.