Matthew J. Sena

Effect of Immediate Fluid Resuscitation on the Rate, Volume, and Duration of Pulmonary Vascular Hemorrhage in a Sheep Model of Penetrating Thoracic Trauma

STUDY OBJECTIVE To determine the effects of early fluid resuscitation on the rate, volume, and duration of hemorrhage using a sheep model of uncontrolled pulmonary vascular hemorrhage. METHODS Sixteen adult sheep were anesthetized and fitted with catheters to measure systemic and pulmonary artery pressures. A branch of the pulmonary vein was then lacerated through an anterolateral thoracotomy, and a chest tube was inserted to monitor hemorrhage volume. Eight animals were assigned to the immediate fluid (IF) resuscitation group and were given 30 mL/kg of lactated Ringers solution over a period of 10 minutes; this treatment was repeated once if normotension was not achieved. The other eight animals received no fluid (NF) and served as nonresuscitated controls. RESULTS The IF animals had a mean hemorrhage volume of 3,494 +/- 1,525 mL, compared with 1,594 +/- 689 mL in the NF group (P < .001). Hemorrhage stopped spontaneously in the NF group at a mean of 29 +/- 9 minutes but took 48 +/- 11 minutes in the IF group (P = .003). During the 20-minute period of fluid resuscitation, the IF animals bled at twice the rate of the NF animals (90 +/- 33 versus 46 +/- 22 mL/minute, respectively; P = .02). During the 10-minute interval after fluids were administered, the rate of hemorrhage remained brisk at 73 +/- 57 mL/minute in the IF group but virtually stopped in the NF group (6 +/- 7 mL/minute; P = .02). CONCLUSION In this sheep model of uncontrolled pulmonary vascular hemorrhage, immediate fluid resuscitation significantly increased the rate, volume, and duration of hemorrhage. The vigorous administration of fluids to patients with penetrating chest trauma has the potential to significantly increase blood loss.

A comparison of predictive equations of energy expenditure and measured energy expenditure in critically ill patients.

PURPOSE Multiple equations exist for predicting resting energy expenditure (REE). The accuracy of these for estimating energy requirements of critically ill patients is not clear, especially for obese patients. We sought to compare REE, calculated with published formulas, with measured REE in a cohort of mechanically ventilated subjects. MATERIALS AND METHODS We retrospectively identified all mechanically ventilated patients with measured body mass index who underwent indirect calorimetry in the intensive care unit. Limits of agreement and Pitmans test of difference in variance were performed to compare REE by equations with REE measured by indirect calorimetry. RESULTS A total of 927 patients were identified, including 401 obese patients. There were bias and poor agreement between measured REE and REE predicted by the Harris-Benedict, Owen, American College of Chest Physicians, and Mifflin equations (P > .05). There was poor agreement between measured and predicted REE by the Ireton-Jones equation, stratifying by sex. Ireton-Jones was the only equation that was unbiased for men and those in weight categories 1 and 2. In all cases except Ireton-Jones, predictive equations underestimated measured REE. CONCLUSION None of these equations accurately estimated measured REE in this group of mechanically ventilated patients, most underestimating energy needs. Development of improved predictive equations for adequate assessment of energy needs is needed.

Identification of low-risk patients with traumatic brain injury and intracranial hemorrhage who do not need intensive care unit admission

BACKGROUND Patients with traumatic brain injury (TBI) and traumatic intracranial hemorrhage are frequently admitted to the intensive care unit (ICU) but never require critical care interventions. Improved ICU triage in this patient population can improve resource utilization and decrease health care costs. We sought to identify a low-risk group of patients with TBI who do not require admission to an ICU. METHODS This is a retrospective cohort study of adult patients with TBI and traumatic intracranial hemorrhage. The need for ICU admission was defined as the presence of a critical care intervention. Patients were considered low risk if there was no critical care intervention before hospital admission. Measured outcomes included delayed critical care interventions at 48 hours and during hospitalization, mortality, and emergency surgery. RESULTS A total of 187 of 320 patients were considered low risk. In the low-risk group, two patients (1.1%; 95% confidence interval [CI], 0.1-3.8) had a delayed critical care intervention within 48 hours of admission and four patients (2.1%; 95% CI, 0.6-5.4) after 48 hours of admission. Two patients (1.1%; 95% CI, 0-3.8) in the low-risk group died. No patients in the low-risk group required neurosurgical intervention. CONCLUSION Patients with TBI without a critical care intervention before admission are at low risk for requiring future critical care interventions. Future studies are required to validate if this low-risk criteria can serve as a safe, cost-effective triage tool for ICU admission.

Preliminary Study of the Effects of Smectite Granules (woundstat) on Vascular Repair and Wound Healing in a Swine Survival Model

BACKGROUND WoundStat (WS) (TraumaCure, Bethesda, MD) is a topical hemostatic agent that effectively stops severe hemorrhage in animal models. To the best of our knowledge, no survival study has been conducted to ensure long-term product safety. We evaluated vascular patency and tissue responses to WS in a swine femoral artery injury model with survival up to 5 weeks. METHODS Anesthetized swine received a standardized femoral artery injury with free hemorrhage for 45 seconds followed by WS application. One hour after application, the WS was removed, the wound copiously irrigated, and the artery repaired using a vein patch. Six groups of three animals received WS and were killed either immediately after surgery or at weekly intervals up to 5 weeks. Three control animals were treated with gauze packing and direct pressure followed by identical vascular repair and survival for 1 week. At the time of killing, angiograms were performed, and tissue was collected for histopathology. RESULTS Hemostasis was complete in all WS animals. All animals survived the procedure, and there were no clinically evident postoperative complications. Vascular repairs were angiographically patent in 15 of 18 animals (83%) receiving WS. Histopathologic examination of WS animals revealed severe diffuse fibrogranulomatous inflammation, early endothelial degeneration with subsequent intimal hyperplasia, moderate myocyte necrosis, and fibrogranulomatous nerve entrapment with axonal degeneration. CONCLUSION Although an effective hemostatic agent, WS use was associated with a substantial local inflammatory response and neurovascular changes up to 5 weeks postinjury.

Lack of Insurance is Associated With Increased Risk for Hernia Complications.

Objective:We sought to determine whether lack of insurance is associated with an increased likelihood of presenting to a hospital with a complicated hernia, and whether insurance status might be associated with clinical outcomes. Context:Delays in elective repair of hernias appear to increase the likelihood of emergency presentation, morbidity, and mortality. Lack of access due to insurance status is a plausible contributor to such delays. Methods:This retrospective study evaluated ambulatory surgical and inpatient hospitalization data from January 1, 2005 through December 31, 2006 in California. Patients who presented for a inguinal, umbilical, or ventral hernia repair or were hospitalized primarily related to the hernia, were at least 5 years old, and had Medicaid (Medi-Cal in California), Medicare, private, or no insurance were included. The main outcome is presentation with a hernia involving bowel obstruction or gangrene, sepsis, or peritonitis. Secondary outcomes evaluated were inpatient mortality, length of hospital stay, and nonoperative management. Results:Out of 147,665 encounters involving hernias, 13,254 (9.0%) involved presentation with a complicated hernia. While only 4.7% of encounters among patients with private insurance were for complicated hernias, 21.1% of those for patients without insurance involved complicated hernias (odds ratio [OR]: 7.02, 95% confidence interval [CI]: 5.05–9.76). Uninsured patients experienced greater mortality (OR: 2.30, 95% CI: 1.01–5.24), lengths of hospital stay (incidence rate ratio: 3.34, 95% CI: 2.61–4.26), and were less likely to undergo operative management (OR: 0.16, 95% CI: 0.11–0.22) than those with private insurance. Conclusions:Lack of insurance is associated with a greater likelihood of presenting with a complicated inguinal, umbilical, or ventral hernia and increased mortality among all patients presenting with hernias at these anatomic sites.

Use of SternaLock Plating System in Acute Treatment of Unstable Traumatic Sternal Fractures

Optimal surgical treatment of unstable sternal fractures is controversial. Wiring provides suboptimal fixation and adaptations of existing non-sternum specific plating systems may be dangerous when rapid sternal reentry is required. We present our experience with the sternal specific fixation system, SternaLock (Biomet Microfixation Inc, Jacksonville, FL), in the acute treatment of transverse sternal body fractures in 2 patients who sustained significant blunt anterior chest wall trauma. SternaLock provides the rigid sternal fixation necessary for reliable fracture healing while offering advantages over other systems with regards to ease of use and safety.

Occult pretransplantation systemic inflammation and posttransplantation vascular changes in a primate arterial allograft model

Background. Occult systemic inflammation, as manifested by increased levels of C-reactive protein (CRP), identify patients at increased risk for renal allograft rejection. The mechanisms linking occult systemic inflammation to these adverse outcomes remain unclear. The purpose of this study was to examine the anatomic and physiologic effects of occult pretransplantation systemic inflammation on posttransplantation allograft outcome in a nonhuman primate model. Methods. Seventy-one healthy male Rhesus macaques were stratified into quartiles based on serum CRP. Five high quartile and six low quartile animals underwent common iliac artery transplantation from male donors. Duplex ultrasound measured graft flow at 3 weeks postoperatively; luminal narrowing was assessed by graft/femoral peak systolic velocity ratio. At 6 weeks, the grafts were harvested and morphometry studies were performed. Vessel wall changes were assessed by measuring the intimal medial area. Results. The allografts placed in high CRP quartile animals had more luminal narrowing by 3 weeks than those placed in low quartile animals, as evidenced by a higher mean graft/femoral peak systolic velocity ratio (1.6 vs. 0.90, P=0.006). Morphometry studies after graft harvest showed increased vessel wall area in the high quartile group versus the low quartile group (1.39 mm2 vs. 1.03 mm2, P=0.018). Conclusions. Occult pretransplantation systemic inflammation is associated with increased intimal thickening and stenosis after arterial allograft transplantation in a primate model. Additional studies are needed to confirm these results and to further investigate potential mechanisms linking pretransplantation systemic inflammation to adverse outcomes after transplantation.

Identification of Barriers to Adaptation of Battlefield Technologies into Civilian Trauma in California

OBJECTIVE To characterize the adoption of routine battlefield medical techniques (tourniquets, hemostatic agents, and tactical combat casualty care into civilian prehospital trauma care and to identify the barriers to their use in the state of California through anonymous electronic survey of local emergency medical services agency (LEMSA) directors. RESULTS The response rate for this survey was 50% (14/28). The majority of LEMSA directors (86%) were emergency medicine physicians. Tourniquets were used by 57% of respondents. The top three reasons cited for not using tourniquets included different injury patterns in civilian trauma, no proven benefit of use, and increased risk of complications. Hemostatic agents were used even less frequently in civilian practice (7%) but had similar barriers to use. Only 36% of LEMSA directors use tactical combat casualty care with tactical emergency medical services, but when used, respondents had higher usage of tourniquets. Overall lack of training, no proven benefit, and expense were the reasons cited for not incorporating military medical techniques. CONCLUSIONS Tourniquets, hemostatic agents, and tactical medical care are the integral components of battlefield medicine and have been lifesaving in these settings. The barriers to this transition are multifactorial. Physicians familiar with these technologies should become advocates for their integration in civilian trauma patient care.

Trauma and Substance Abuse: Deadly Consequences of Intravenous Percocet Tablets

BACKGROUND The prevalence of drug or alcohol addiction among trauma patients approaches 40%, yet many require narcotics during admission for adequate pain control. Provider awareness is the most reasonable option to avoid the devastating consequence of narcotic tablet injection. OBJECTIVE To illustrate the misuse of oral narcotics and to heighten provider awareness of a potential cause for acute respiratory failure in recently discharged patients. CASE REPORT A 20-year-old man was admitted to the hospital after an assault to the head and face. He was discharged from the hospital with 30 oral Percocet® (Endo Pharmaceuticals, Newark, DE) tablets after 24 h of observation. The day after discharge, emergency medical services were called to his residence for a decreased level of consciousness. During transport to the Emergency Department, he went into cardiac arrest with pulseless electrical activity. He could not be resuscitated. Postmortem biochemical and anatomical evidence suggested that the patient had attempted to inject crushed Percocet® tablets, which resulted in acute foreign body pulmonary microembolism and death. CONCLUSION Patients with a history of substance abuse may be inclined to crush and inject oral narcotics. Narcotic injection should be considered in recently discharged patients who present with pulmonary failure. Patients with suspected narcotic addiction should be counseled before discharge on the risks of misusing oral medications in this fashion.