Mark T. Muir

The etiology of pneumoperitoneum in the 21st century.

BACKGROUND We sought to determine the origin of free intraperitoneal air in this era of diminishing prevalence of peptic ulcer disease and imaging studies. In addition, we attempted to stratify the origin of free air by the size of the air collection. METHODS We queried our hospital database for “pneumoperitoneum” from 2005 to 2007 and for proven gastrointestinal perforation from 2000 to 2007. Massive amount of free air was defined as any air pocket greater than 10.0 cm. RESULTS Among patients with free air, the predominant causes were perforated viscus (41%) and postoperative (<8 days) residual air (37%). For patients with visceral perforation, only 45% had free air on imaging studies, and for these patients, the predominant cause was peptic ulcer (16%), diverticulitis (16%), trauma (14%), malignancy (14%), bowel ischemia (10%), appendicitis (6%), and endoscopy (4%). The likelihood that free air was identified on an imaging study by lesion was 72% for perforated peptic ulcer, 57% for perforated diverticulitis, but only 8% for perforated appendicitis. The origin of massive free air was equally likely to be gastroduodenal, small bowel, or colonic perforation. CONCLUSION The cause of free air when surgical pathology is the source has substantially changed from previous reports. LEVEL OF EVIDENCE Epidemiologic study, level IV.

Mortality, Mauling, and Maiming by Vicious Dogs

Objective:Maiming and death due to dog bites are uncommon but preventable tragedies. We postulated that patients admitted to a level I trauma center with dog bites would have severe injuries and that the gravest injuries would be those caused by pit bulls. Design:We reviewed the medical records of patients admitted to our level I trauma center with dog bites during a 15-year period. We determined the demographic characteristics of the patients, their outcomes, and the breed and characteristics of the dogs that caused the injuries. Results:Our Trauma and Emergency Surgery Services treated 228 patients with dog bite injuries; for 82 of those patients, the breed of dog involved was recorded (29 were injured by pit bulls). Compared with attacks by other breeds of dogs, attacks by pit bulls were associated with a higher median Injury Severity Scale score (4 vs. 1; P = 0.002), a higher risk of an admission Glasgow Coma Scale score of 8 or lower (17.2% vs. 0%; P = 0.006), higher median hospital charges (

Novel Toxin Assays Implicate Mycoplasma pneumoniae in Prolonged Ventilator Course and Hypoxemia

10,500 vs.

Novel therapeutic strategies targeting the pathogenic T-cells in multiple sclerosis.

7200; P = 0.003), and a higher risk of death (10.3% vs. 0%; P = 0.041). Conclusions:Attacks by pit bulls are associated with higher morbidity rates, higher hospital charges, and a higher risk of death than are attacks by other breeds of dogs. Strict regulation of pit bulls may substantially reduce the US mortality rates related to dog bites.

Compensatory reserve index: Performance of a novel monitoring technology to identify the bleeding trauma patient

BACKGROUND Community-acquired respiratory distress syndrome (CARDS) toxin is a unique Mycoplasma pneumoniae virulence factor. Molecular assays targeting this toxin are more sensitive than existing diagnostics, but these assays have not been used to investigate the role of M pneumoniae as a nosocomial infection in critical illness. We sought to determine the incidence of M pneumoniae among mechanically ventilated subjects using these novel assays and to investigate the impact of this pathogen on pulmonary outcomes. METHODS We conducted a prospective observational study enrolling subjects with suspected ventilator-associated pneumonia (VAP) undergoing BAL in the surgical trauma ICU at a level I trauma center. Lavage fluid and serum samples were tested for M pneumoniae using assays to detect CARDS toxin gene sequences, protein, or antitoxin antibodies. RESULTS We collected samples from 37 subjects, with 41% (15 of 37) testing positive using these assays. The positive and negative groups did not differ significantly in baseline demographic characteristics, including age, sex, injury severity, or number of ventilator days before bronchoscopy. The positive group had significantly fewer ventilator-free days (P = .04) and lower average oxygenation (P = .02). These differences were most pronounced among subjects with ARDS. CONCLUSIONS Evidence is provided that M pneumoniae is present in a substantial number of subjects with suspected VAP. Subjects testing positive experience a significantly longer ventilator course and worse oxygenation compared with subjects testing negative.

Comparison of Compensatory Reserve and Arterial Lactate as Markers of Shock and Resuscitation

Multiple sclerosis is a chronic disease in which immune cells incite inflammation in the central nervous system, ultimately resulting in the destruction of the myelin nerve sheath. Pathogenic CD4+ T-cells are believed to be responsible for initiating this process. Recent advances in molecular biology, such as transgenic and knockout animal models, genomics and proteomics, have allowed for a much greater understanding of the cellular and subcellular pathways involved in autoimmunity. The end result is an ever more specific array of potential therapeutic agents, each designed to target one component of the dysregulated immune system and in some cases, specific to each individual patient. The mechanisms, promises and pitfalls of these various strategies for the treatment of multiple sclerosis are the topic of this review.

Colon Trauma: Evidence-Based Practices

Introduction: Hemorrhage is one of the most substantial causes of death after traumatic injury. Standard measures, including systolic blood pressure (SBP), are poor surrogate indicators of physiologic compromise until compensatory mechanisms have been overwhelmed. Compensatory Reserve Index (CRI) is a novel monitoring technology with the ability to assess physiologic reserve. We hypothesized CRI would be a better predictor of physiologic compromise secondary to hemorrhage than traditional vital signs. Methods: A prospective observational study of 89 subjects meeting trauma center activation criteria at a single level I trauma center was conducted from October 2015 to February 2016. Data collected included demographics, SBP, heart rate, and requirement for hemorrhage-associated, life-saving intervention (LSI) (i.e., operation or angiography for hemorrhage, local or tourniquet control of external bleeding, and transfusion >2 units PRBC). Receiver-operator characteristic (ROC) curves were formulated and appropriate thresholds were calculated to compare relative value of the metrics for predictive modeling. Results: For predicting hemorrhage-related LSI, CRI demonstrated a sensitivity of 83% and a negative predictive value (NPV) of 91% as compared with SBP with a sensitivity to detect hemorrhage of 26% (P < 0.05) and an NPV of 78%. ROC curves generated from admission CRI and SBP measures demonstrated values of 0.83 and 0.62, respectively. CRI identified significant hemorrhage requiring potentially life-saving therapy more reliably than SBP (P < 0.05). Conclusion: The CRI device demonstrated superior capacity over systolic blood pressure in predicting the need for posttraumatic hemorrhage intervention in the acute resuscitation phase after injury.

Nuclear Receptors and Autoimmune Disease: The Potential of PPAR Agonists to Treat Multiple Sclerosis

BACKGROUND During traumatic hemorrhage, the ability to identify shock and intervene prior to decompensation is paramount to survival. Lactate is extremely sensitive to shock and its clearance has been demonstrated a useful gauge of shock and resuscitation status. Though lactate can be measured in the field, logistical constraints render it impractical in certain environments. The Compensatory Reserve represents a new clinical measurement reflecting the remaining capacity to compensate for hypoperfusion. We hypothesized the compensatory reserve index (CRI) would be an effective surrogate marker of shock and resuscitation compared to lactate. METHODS The CRI device was placed on consecutive patients meeting trauma center activation criteria and remained on the patient until discharge, admission, or transport to operating suite. All subjects had a lactate level measured as part of their routine admission metabolic analysis. Time-corresponding CRI and lactate values were matched in regards to initial and subsequent lactate levels. Mean time from lactate sample collection to data availability in the electronic medical record was calculated. Predictive capacity of CRI and lactate in predicting hemorrhage was determined by receiver-operative characteristic curve analysis. Correlation analysis was performed to determine if any association existed between changing CRI and lactate values. RESULTS Receiver-operator characteristic (ROC) curves were generated and area under the curve was 0.8052 and 0.8246 for CRI and lactate, respectively. There was no significant difference in each parameters ability to predict hemorrhage (p= 0.8015). The mean duration from lactate sample collection to clinical availability was 44 minutes while CRI values were available immediately. Analysis of the concomitant change in serial CRI and lactate levels revealed a Spearmans correlation coefficient of -0.73 (p < 0.01). CONCLUSION CRI performed with equivalent predictive capacity to lactate with respect to identifying initial perfusion status associated with hemorrhage and subsequent resuscitation. LEVEL OF EVIDENCE II.BACKGROUND During traumatic hemorrhage, the ability to identify shock and intervene before decompensation is paramount to survival. Lactate is extremely sensitive to shock, and its clearance has been demonstrated a useful gauge of shock and resuscitation status. Though lactate can be measured in the field, logistical constraints render it impractical in certain environments. The compensatory reserve represents a new clinical measurement reflecting the remaining capacity to compensate for hypoperfusion. We hypothesized the compensatory reserve index (CRI) would be an effective surrogate marker of shock and resuscitation compared to lactate. METHODS The CRI device was placed on consecutive patients meeting trauma center activation criteria and remained on the patient until discharge, admission, or transport to operating suite. All subjects had a lactate level measured as part of their routine admission metabolic analysis. Time-corresponding CRI and lactate values were matched in regards to initial and subsequent lactate levels. Mean time from lactate sample collection to data availability in the electronic medical record was calculated. Predictive capacity of CRI and lactate in predicting hemorrhage was determined by receiver-operator characteristic curve analysis. Correlation analysis was performed to determine if any association existed between changing CRI and lactate values. RESULTS Receiver-operator characteristic (ROC) curves were generated and area under the curve was 0.8052 and 0.8246 for CRI and lactate, respectively. There was no significant difference in each parameter’s ability to predict hemorrhage (p = 0.8015). The mean duration from lactate sample collection to clinical availability was 44 minutes whereas CRI values were available immediately. Analysis of the concomitant change in serial CRI and lactate levels revealed a Spearman’s correlation coefficient of −0.73 (p < 0.01). CONCLUSION CRI performed with equivalent predictive capacity to lactate with respect to identifying initial perfusion status associated with hemorrhage and subsequent resuscitation. LEVEL OF EVIDENCE Diagnostic, Level II.

Time is the enemy: Mortality in trauma patients with hemorrhage from torso injury occurs long before the “golden hour”

Abstract Colon injury is not uncommon and occurs in about a half of patients with penetrating hollow viscus injuries. Despite major advances in the operative management of penetrating colon wounds, there remains discussion regarding the appropriate treatment of destructive colon injuries, with a significant amount of scientific evidence supporting segmental resection with primary anastomosis in most patients without comorbidities or large transfusion requirement. Although literature is sparse concerning the management of blunt colon injuries, some studies have shown operative decision based on an algorithm originally defined for penetrating wounds should be considered in blunt colon injuries. The optimal management of colonic injuries in patients requiring damage control surgery (DCS) also remains controversial. Studies have recently reported that there is no increased risk compared with patients treated without DCS if fascial closure is completed on the first reoperation, or that a management algorithm for penetrating colon wounds is probably efficacious for colon injuries in the setting of DCS as well.