Hyperventilation During Manual Ventilation Can Be Reduced Using a Novel Ventilator but Not With Education Interventions.

INTRODUCTION: Traumatic brain injury (TBI) is the leading cause of combat casualties in modern war with an estimated 20% of casualties experiencing head injury. Since the release of the Brain Trauma Foundation's Guidelines for the Management of Severe Traumatic Brain Injury in 1995, recommendations for management of TBI have included the avoidance of routine hyperventilation. However, both published and anecdotal data suggest that many patients with TBI are inappropriately ventilated during transport, thereby increasing the risk of morbidity and mortality from secondary brain injury. MATERIALS AND METHODS: Enlisted Air Force personnel with prior emergency medical technician training completing a 3-week trauma course were evaluated on their ability to provide manual ventilation. Participants provided manual ventilation using either an in-situ endotracheal tube (ETT) or standard face mask on a standardized simulated patient manikin with TBI on the first and last days of the course. Manual ventilation was provided via a standard manual ventilator and a novel manual ventilator designed to limit tidal volume (VT) and respiratory rate (RR). Participants were given didactic and hands-on training on the third day of the course. Half of the participants were given simulator feedback during the hands-on training. All students provided 2 minutes of manual ventilation with each respirator. Data were collected on the breath-to-breath RR, VT, and peak airway pressures generated by the participant for each trial and were averaged for each trial. A minute ventilation (MV) was then derived from the calculated RR and VT. RESULTS: One hundred fifty-six personnel in the trauma course were evaluated in this study. Significant differences were found in the participant's performance with manual ventilation with the novel compared to the traditional ventilator. Before training, MV with the novel ventilator was less than with the traditional ventilator by 2.1 ± 0.4 L/min (P = .0003) and 1.6 ± 0.5 L/min (P = .0489) via ETT and face mask, respectively. This effect persisted after training with a difference between the devices of 1.8 ± 0.4 L/min (P = .0069) via ETT. Both traditional education interventions (didactics with hands-on training) and simulator-based feedback did not make a significant difference in participant's performance in delivering MV. CONCLUSIONS: The use of a novel ventilator that limits RR and VT may be useful in preventing hyperventilation in TBI patients. Didactic education and simulator-based feedback training may not have significant impact on improving ventilation practices in prehospital providers.

Induction of endothelial barrier dysfunction by serum factors in rats subjected to traumatic brain injury and hemorrhagic shock.

Traumatic brain injury (TBI) has been associated with the development of indirect acute respiratory distress syndrome (ARDS). However, the causative relationship between TBI and lung injury remains unclear. To explore potential mechanisms linking TBI with the development of ARDS, we characterized the effects of serum factors released following TBI and hemorrhagic shock (HS) in a rat model on the pulmonary endothelial cell (EC) barrier dysfunction, a key feature of ARDS. We found that serum samples from animals exposed to both controlled cortical impact (CCI) and HS, but not from sham-operated rats induced significant barrier dysfunction in human pulmonary artery EC monolayers at 2 days post injury. Thrombin inhibitor and thrombin receptor antagonist attenuated the acute phase of the serum-induced trans-endothelial resistance (TER) decline caused by CCI-HS serum, but not in later time points. However, both the early and late phases of CCI-HS-induced EC permeability were inhibited by heparin. The barrier disruptive effects of CCI-HS serum were also prevented by serum preincubation with heparin-sepharose. Pulmonary EC treated for 3 h with serum from CCI-HS rats demonstrated a significant decline in expression of EC junctional protein, VE-Cadherin, and disassembly of peripheral EC adherens junction complexes monitored by immunostaining with VE-cadherin antibody. These results suggest that exposure to CCI-HS causes early and late-phase barrier disruptive effects in vascular endothelium. While thrombin-PAR1 signaling has been identified as a mechanism of acute EC permeability increase by CCI-HS serum, the factor(s) defining long-term EC barrier disruption in CCI-HS model remains to be determined.

Is Tranexamic Acid Associated With Mortality or Multiple Organ Failure Following Severe Injury?

BACKGROUND: Tranexamic acid (TXA) administration is recommended in severely injured trauma patients. We examined TXA administration, admission fibrinolysis phenotypes, and clinical outcomes following traumatic injury and hypothesized that TXA was associated with increased multiple organ failure (MOF). METHODS: Two-year, single-center, retrospective investigation. Inclusion criteria were age ≥ 18 years, Injury Severity Score (ISS) >16, admitted from scene of injury, thromboelastography within 30 min of arrival. Fibrinolysis was evaluated by lysis at 30 min (LY30) and fibrinolysis phenotypes were defined as: Shutdown: LY30 ≤ 0.8%, Physiologic: LY30 0.81-2.9%, Hyperfibrinolysis: LY30 ≥ 3.0%. Primary outcomes were 28-day mortality and MOF. The association of TXA with mortality and MOF was assessed among the entire study population and in each of the fibrinolysis phenotypes. RESULTS: Four hundred twenty patients: 144/420 Shutdown (34.2%), 96/420 Physiologic (22.9%), and 180/410 Hyperfibrinolysis (42.9%). There was no difference in 28-day mortality by TXA administration among the entire study population (P = 0.52). However, there was a significant increase in MOF in patients who received TXA (11/46, 23.9% vs 16/374, 4.3%; P < 0.001). TXA was associated MOF (OR: 3.2, 95% CI 1.2-8.9), after adjusting for confounding variables. There was no difference in MOF in patients who received TXA in the Physiologic (1/5, 20.0% vs 7/91, 7.7%; P = 0.33) group. There was a significant increase in MOF among patients who received TXA in the Shutdown (3/11, 27.3% vs 5/133, 3.8%; P = 0.001) and Hyperfibrinolysis (7/30, 23.3% vs 5/150, 3.3%; P = 0.001) groups. CONCLUSIONS: Administration of TXA following traumatic injury was associated with MOF in the fibrinolysis shutdown and hyperfibrinolysis phenotypes and warrants continued evaluation.

Management of the Potential Organ Donor in the ICU: Society of Critical Care Medicine/American College of Chest Physicians/Association of Organ Procurement Organizations Consensus Statement.

This document was developed through the collaborative efforts of the Society of Critical Care Medicine, the American College of Chest Physicians, and the Association of Organ Procurement Organizations. Under the auspices of these societies, a multidisciplinary, multi-institutional task force was convened, incorporating expertise in critical care medicine, organ donor management, and transplantation. Members of the task force were divided into 13 subcommittees, each focused on one of the following general or organ-specific areas: death determination using neurologic criteria, donation after circulatory death determination, authorization process, general contraindications to donation, hemodynamic management, endocrine dysfunction and hormone replacement therapy, pediatric donor management, cardiac donation, lung donation, liver donation, kidney donation, small bowel donation, and pancreas donation. Subcommittees were charged with generating a series of management-related questions related to their topic. For each question, subcommittees provided a summary of relevant literature and specific recommendations. The specific recommendations were approved by all members of the task force and then assembled into a complete document. Because the available literature was overwhelmingly comprised of observational studies and case series, representing low-quality evidence, a decision was made that the document would assume the form of a consensus statement rather than a formally graded guideline. The goal of this document is to provide critical care practitioners with essential information and practical recommendations related to management of the potential organ donor, based on the available literature and expert consensus.

Topical hemostatic agents and dressings in the prehospital setting.

PURPOSE OF REVIEW: Death from exsanguinating hemorrhage remains a priority in the management of combat casualties and civilian trauma patients with truncal and junctional injuries. Appropriate use of hemostatic agents and dressings in the prehospital setting may allow for earlier control and an improved survival rate. RECENT FINDINGS: Third-generation chitosan-based hemostatic agents and dressings appear to be equally efficacious to the dressing currently deployed by the US military forces in the management of hemorrhage not amenable to tourniquet placement. Unfortunately, a lack of clinical trials places a heavy reliance on anecdotal reports and laboratory studies in agent selection and application. SUMMARY: Efficacy of currently available hemostatic agents and dressings appears to have plateaued in recent years although new agents and delivery mechanisms under development may improve control in cases of severe hemorrhage.

The epidemiology of Critical Care Air Transport Team operations in contemporary warfare.

Critical Care Air Transport Teams (CCATTs) have evolved as a vital component of the U.S. Air Force's aeromedical evacuation system. Previous epidemiological research in this area is limited. The objective of this commentary is to highlight the importance of obtaining robust epidemiological data regarding patients transported by CCATTs. A limited epidemiological analysis was performed to describe CCATT patients transported during Operation Enduring Freedom and the waning months of Operation Iraqi Freedom. CCATT transports for the calendar year 2011 were examined as recorded in the U.S. Transportation Command Regulating and Command and Control (C2) Evacuation System database. As many as 290 CCATT primary patient transport records were reviewed. Of these, 58.6% of patients had multiple injuries, 15.9% of patients had traumatic brain injury, 7% had acute coronary syndromes, and 24.8% of all transports were for nonbattle-related injuries. The most common International Classification of Disease, 9th Edition, Clinical Modification coded injury was bilateral lower extremity amputation (40%). Explosive blasts were the top mechanism of injury for patients requiring CCAT. The distribution of injuries and illnesses requiring CCAT appear to have changed compared to previous conventional conflicts. Understanding the epidemiology of casualties evacuated by CCATT during modern warfare is a prerequisite for the development of effective predeployment training to ensure optimal outcomes for critically ill and injured warriors.

Performance assessment in airway management training for nonanesthesiology trainees: an analysis of 4,282 airway procedures performed at a level-1 trauma center.

BACKGROUND: Although the use of an anesthesiology "airway" rotation to train the nonanesthesiologist is commonly employed, little data exist on the utility, clinical exposure, and outcomes of these programs. METHODS: A prospectively collected observational dataset of airway procedures completed by trainees in a 4-week, anesthesiology-based, airway rotation at an academic, level-1 trauma center from July 2010 to September 2012 was reviewed. Prospectively defined data points were collected through an online data tool and included patient demographics, location, date, best laryngoscopic view, and attempt details. At the authors' institution, an attending trauma anesthesiologist is present for all intubation attempts. The primary outcome was first-attempt success. RESULTS: A total of 4,282 self-reported, airway procedures were identified. The median number of procedures performed was 50.4 ± 13.2 (range, 20 to 93; 25th quartile = 41; 75th quartile = 57). Multivariate logistic regression analysis modeling of first-attempt success rate identified two independent predictors of success: rotation week (odds ratio, 1.42; 95% CI, 1.32 to 1.61; P < 0.0001) and number of previous intubation attempts before rotation (odds ratio, 1.23; 95% CI, 1.03 to 1.46; P = 0.02. In addition, the percentage of cases with a self-reported laryngoscopic grade 1 view increased significantly from 61 to 74% (P = 0.015) from week 1 to week 4 of the rotation. CONCLUSIONS: An anesthesiology-based program for airway training of nonanesthesiologists demonstrates improved self-reported, perceived first-attempt success over the course of training with improved ability to visualize glottic structures.

Effect of video laryngoscopy on trauma patient survival: a randomized controlled trial.

BACKGROUND: Many resuscitation scenarios include the use of emergency intubation to support injured patients. New video-guided airway management technology is available, which may minimize the risk to patients from this procedure. METHODS: This was a controlled clinical trial conducted in the trauma receiving unit in a university-affiliated urban hospital in which 623 consecutive adult patients requiring emergency airway management were prospectively randomized to intubation with either the direct laryngoscope (DL) or the GlideScope video laryngoscope (GVL) device. RESULTS: The primary outcome was survival to hospital discharge. There was no significant difference in mortality between the GVL group (28 [9%] of 303) and the DL group (24 [8%] of 320) (p = 0.43) for all patients. Within a smaller cohort identified retrospectively, there was a higher mortality rate seen in the subgroup of patients with severe head injuries (head Abbreviated Injury Scale [AIS] score > 3) who were randomized to intubation with GVL (22 [30%] of 73) versus DL (16 [14%] of 112) (p = 0.047). Among all patients, median intubation duration in seconds was significantly higher for the GVL group (median, 56; interquartile range, 40-81) than for the DL group (median, 40; interquartile range, 24-68) (p < 0.001). Among those with severe head injuries, median intubation duration in seconds was also significantly higher for the GVL group (median, 74) than for the DL group (median, 65) (p < 0.003). Correspondingly, this group also experienced a greater incidence of low oxygen saturations of 80% or less (27 [50%] of 54 for the GVL group and 15 [24%] of 63 for the DL group; p = 0.004). There were no significant differences between the two groups in first-pass success (80% for GVL and 81% for DL, p = 0.46). CONCLUSION: Use of the GlideScope did not influence survival to hospital discharge among all patients and was associated with longer intubation times than direct laryngoscopy. Among the video laryngoscope cohort, a smaller subgroup of severe head injury trauma patients identified retrospectively seemed to be associated with a greater incidence of hypoxia of 80% or less and mortality.

Critical care considerations in the management of the trauma patient following initial resuscitation.

BACKGROUND: Care of the polytrauma patient does not end in the operating room or resuscitation bay. The patient presenting to the intensive care unit following initial resuscitation and damage control surgery may be far from stable with ongoing hemorrhage, resuscitation needs, and injuries still requiring definitive repair. The intensive care physician must understand the respiratory, cardiovascular, metabolic, and immunologic consequences of trauma resuscitation and massive transfusion in order to evaluate and adjust the ongoing resuscitative needs of the patient and address potential complications. In this review, we address ongoing resuscitation in the intensive care unit along with potential complications in the trauma patient after initial resuscitation. Complications such as abdominal compartment syndrome, transfusion related patterns of acute lung injury and metabolic consequences subsequent to post-trauma resuscitation are presented. METHODS: A non-systematic literature search was conducted using PubMed and the Cochrane Database of Systematic Reviews up to May 2012. RESULTS AND CONCLUSION: Polytrauma patients with severe shock from hemorrhage and massive tissue injury present major challenges for management and resuscitation in the intensive care setting. Many of the current recommendations for "damage control resuscitation" including the use of fixed ratios in the treatment of trauma induced coagulopathy remain controversial. A lack of large, randomized, controlled trials leaves most recommendations at the level of consensus, expert opinion. Ongoing trials and improvements in monitoring and resuscitation technologies will further influence how we manage these complex and challenging patients.

The provision of sophisticated critical care beyond the hospital: lessons from physiology and military experiences that apply to civil disaster medical response.

OBJECTIVE: The provision of sophisticated medical care in an austere environment is challenging. During and after a mass casualty event, it is likely that critical care services will be needed beyond an intensive care unit (ICU) setting. The objective of this article is to explore existing ICU care systems such as military aeromedical transport that may be applicable to disaster medicine and to providing critical care outside of an ICU setting. RESULTS: The U.S. Air Force Critical Care Aeromedical Transport (CCAT) Teams were developed in 1994 in response to an unmet military need for long-range air transport of critically ill and injured patients. This system has transported several thousand ICU patients and is an applicable model for the future development of extrahospital critical care capabilities needed during a disaster. We also discuss civilian aeromedical critical care systems, the types of medical devices used, and their applicability to disaster medical response. CONCLUSION: The U.S. Air Force CCAT Team program, as well as many civilian critical care air ambulance services, provides a workable starting point for the development of disaster medical critical care response capabilities for disaster medical systems.