Qualitative investigation of military surgical resuscitation teams: what are the drivers of success of a rapid response team?

OBJECTIVES

This qualitative study explores the characteristics of a specialised military medical rapid response team (MRRT), the surgical resuscitation team (SRT). Despite mixed evidence of efficacy, civilian MRRTs are widely employed, with significant variation in structure and function. Recent increased use of these teams to mitigate patient risk in challenging healthcare scenarios, such as global pandemics, mass casualty events and resource-constrained health systems, mandates a reconceptualisation of how civilian MRRTs are created, trained and used. Here, we study the core functions and foundational underpinnings of SRTs and discuss how civilian MRRTs might learn from their military counterparts.

DESIGN

Semistructured interview-based study using Descriptive Qualitative Research methodology and Thematic Analysis.

SETTING

Remote audio interviews conducted via Zoom.

PARTICIPANTS

Participants included 15 members of the United States Special Operations Command SRTs, representing all medical specialties of the SRT as well as operational planners.

RESULTS

Adaptability was identified as a core function of SRTs and informed by four foundational underpinnings: mission variability, shared values and principles, interpersonal and organisational trust and highly effective teaming. Our findings provide three important insights for civilian MRRTs: (1) team member roles should not be defined by silos of professional specialisation, (2) trust is a key factor in the teaming process and (3) team principles and values result in and are reinforced by organisational trust.

CONCLUSION

This study offers the first in-depth investigation of a unique military MRRT. Important insights that may offer benefit to civilian MRRT practices include enabling the breakdown of traditional division of labour, allowing for and promoting deep interpersonal and professional familiarity, and facilitating a cycle of positive reinforcement between teams and organisations. Future investigation of small team limitations, comparability to civilian MRRTs, and the team relationship to the larger organisation are needed to better understand how these teams function in a healthcare system and translate to civilian practice.

Developing the Ready Military Medical Force: military-specific training in Graduate Medical Education

Introduction

Graduate Medical Education plays a critical role in training the next generation of military physicians, ensuring they are ready to uphold the dual professional requirements inherent to being both a military officer and a military physician. This involves executing the operational duties as a commissioned leader while also providing exceptional medical care in austere environments and in harm's way. The purpose of this study is to review prior efforts at developing and implementing military unique curricula (MUC) in residency training programs.

Methods

We performed a literature search in PubMed (MEDLINE), Embase, Web of Science, and the Defense Technical Information Center through August 8, 2023, including terms "graduate medical education" and "military." We included articles if they specifically addressed military curricula in residency with terms including "residency and operational" or "readiness training", "military program", or "military curriculum".

Results

We identified 1455 articles based on title and abstract initially and fully reviewed 111. We determined that 64 articles met our inclusion criteria by describing the history or context of MUC, surveys supporting MUC, or military programs or curricula incorporated into residency training or military-specific residency programs.

Conclusion

We found that although there have been multiple attempts at establishing MUC across training programs, it is difficult to create a uniform curriculum that can be implemented to train residents to a single standard across services and specialties.

Committee on Surgical Combat Casualty Care Position Statement: Neurosurgical Capability for the Optimal Management of Traumatic Brain injury During Deployed Operations. Including Invited Commentaries

BACKGROUND

Experiences over the last 3 decades of war have demonstrated a high incidence of Traumatic Brain Injury (TBI) resulting in a persistent need for a neurosurgical capability within the deployed theatre of operations. Despite this, no doctrinal requirement for a deployed neurosurgical capability exists. Through an iterative process, the Joint Trauma System Committee on Surgical Combat Casualty Care (CoSCCC) developed a Position Statement to inform medical and non-medical military leaders about the risks of the lack of a specialized neurosurgical capability.

METHODS

The need for deployed neurosurgical capability Position Statement was identified during the spring 2021 CoSCCC meeting. A tri-service working group of experienced forward-deployed caregivers developed a preliminary statement. An extensive iterative review process was then conducted to ensure that the intended messaging was clear to senior medical leaders and operational commanders. To provide additional context and a civilian perspective, statement commentaries were solicited from civilian clinical experts including a recently retired military trauma surgeon boarded in Neurocritical Care, a trauma surgeon instrumental in developing the Brain Injury Guidelines (BIG), a practicing neurosurgeon with world-renowned expertise in TBI, and the Chair of the Committee on Trauma (COT).

RESULTS

After multiple revisions, Position Statement was finalized it was approved by the CoSCCC membership in February 2023. Challenges identified include: 1) military neurosurgeon attrition; 2) the lack of a doctrinal neurosurgical capabilities requirement during deployed combat operations; 3) the need for neurosurgical telemedicine capability and in-theatre CT scans to triage TBI casualties requiring neurosurgical care.

CONCLUSION

Challenges identified regarding neurosurgical capabilities within the deployed trauma system include military neurosurgeon attrition and the lack of a doctrinal requirement for neurosurgical capability during deployed combat operations. To mitigate risk to the force in a future peer-peer conflict several evidence-based recommendations are made. The solicited civilian commentaries strengthen these recommendations by putting them into the context of civilian TBI management. These neurosurgical capabilities position statement is intended to be a forcing function and a communication tool to inform operational commanders and military medical leaders on the use of these teams on current and future battlefields.

LEVEL OF EVIDENCE

Brief Report, 3.

Engineering Human Cells Expressing CRISPR/Cas9-Synergistic Activation Mediators for Recombinant Protein Production

Recombinant engineering for protein production commonly employs plasmid-based gene templates for introduction and expression of genes in a candidate cell system in vitro. Challenges to this approach include identifying cell types that can facilitate proper post-translational modifications and difficulty expressing large multimeric proteins. We hypothesized that integration of the CRISPR/Cas9-synergistic activator mediator (SAM) system into the human genome would be a powerful tool capable of robust gene expression and protein production. SAMs are comprised of a "dead" Cas9 (dCas9) linked to transcriptional activators viral particle 64 (VP64), nuclear factor-kappa-B p65 subunit (p65), and heat shock factor 1 (HSF1) and are programmable to single or multiple gene targets. We integrated the components of the SAM system into human HEK293, HKB11, SK-HEP1, and HEP-g2 cells using coagulation factor X (FX) and fibrinogen (FBN) as proof of concept. We observed upregulation of mRNA in each cell type with concomitant protein expression. Our findings demonstrate the capability of human cells stably expressing SAM for user-defined singleplex and multiplex gene targeting and highlight their broad potential utility for recombinant engineering as well as transcriptional modulation across networks for basic, translational, and clinical modeling and applications.

Airborne! UAV Delivery of Blood Products and Medical Logistics for Combat Zones

BACKGROUND

Innovative solutions to resupply critical medical logistics and blood products may be required in future near-peer conflicts. Unmanned aerial vehicles (UAVs) are increasingly being used in austere environments and may be a viable platform for medical resupply and the transport of blood products.

METHODS

A literature review on PubMed and Google Scholar up to March of 2022 yielded a total of 27 articles that were included in this narrative review. The objectives of this article are to discuss the current limitations of prehospital blood transfusion in military settings, discuss the current uses of UAVs for medical logistics, and highlight the ongoing research surrounding UAVs for blood product delivery.

DISCUSSION

UAVs allow for the timely delivery of medical supplies in numerous settings and have been utilized for both military and civilian purposes. Investigations into the effects of aeromedical transportation on blood products have found minimal blood product degradation when appropriately thermoregulated and delivered in a manner that minimizes trauma. UAV delivery of blood products is now actively being explored by numerous entities around the globe. Current limitations surrounding the lack of high-quality safety data, engineering constraints over carrying capacity, storage capability, and distance traveled, as well as air space regulations persist.

CONCLUSION

UAVs may offer a novel solution for the transport of medical supplies and blood products in a safe and timely manner for the forward-deployed setting. Further research on optimal UAV design, optimal delivery techniques, and blood product safety following transport should be explored prior to implementation.

Engineering CRISPR/Cas9 for Multiplexed Recombinant Coagulation Factor Production

Current hemostatic agents are obtained from pooled plasma from multiple donors requiring costly pathogen screening and processing. Recombinant DNA-based production represents an engineering solution that could improve supply, uniformity, and safety. Current approaches are typically for single gene candidate peptides and often employ non-human cells. We devised an approach where multiple gene products could be produced from a single population of cells. We identified gene specific Synergistic Activation Mediators (SAM) from the CRISPR/Cas9 system for targeted overexpression of coagulation factors II, VII, IX, X, and fibrinogen. The components of the CRISPR-SAM system were expressed in Human Embryonic Kidney Cells (HEK293), and single (singleplex) or multi-gene (multiplex) upregulation was assessed by quantitative RT-PCR (qRT-PCR) and protein expression by ELISA analysis. Factor II, VII, IX, and X singleplex and multiplex activation resulted in 120–4700-fold and 60–680-fold increases in gene expression, respectively. Fibrinogen sub-unit gene activation resulted in a 1700–92,000-fold increases and 80–5500-fold increases in singleplex or multiplex approaches, respectively. ELISA analysis showed a concomitant upregulation of candidate gene products. Our findings demonstrate the capability of CRISPR/Cas9 SAMs for single or multi-agent production in human cells and represent an engineering advance that augments current recombinant peptide production techniques.

Adenosine, lidocaine, and magnesium for attenuating ischemia reperfusion injury from resuscitative endovascular balloon occlusion of the aorta in a porcine model

BACKGROUND

Minimally invasive resuscitative endovascular balloon occlusion of the aorta (REBOA) following noncompressible hemorrhage results in significant ischemia reperfusion injury (IRI). Adverse outcomes from IRI include organ dysfunction and can result in profound hemodynamic and molecular compromise. We hypothesized that adenosine, lidocaine, and magnesium (ALM) attenuates organ injury and inflammation responses following REBOA IRI in a porcine model of hemorrhage.

METHODS

Animals underwent a 20% controlled hemorrhage followed by 45 minutes of supraceliac balloon occlusion. They were randomized into two groups: control (n = 9) and ALM intervention (n = 9) to include a posthemorrhage, pre-REBOA bolus (200 mL of 3% NaCl ALM) followed by a continuous drip (2 mL/kg per hour of 0.9% NaCl ALM) during the 4-hour resuscitative period. Primary outcomes included hemodynamic parameters, gene expression of inflammatory signaling molecules, and plasma concentrations of select cytokines and chemokines.

RESULTS

The ALM cohort demonstrated a significant reduction in cardiac output and cardiac index. Plasma concentrations of interleukin 2 and interleukin 10 were significantly lower 3 hours post-REBOA in animals treated with ALM versus vehicle. Interleukin 4 levels in plasma were also lower with ALM at 3 and 4 hours post-REBOA (p < 0.05). Liver expression of IL1RN, MTOR, and LAMP3 messenger RNA was significantly lower with ALM as compared with the vehicle. No significant difference in large bowel gene expression was observed between treatments.

CONCLUSION

In a porcine model of hemorrhage, ALM treatment mitigated inflammatory responses early during post-REBOA resuscitation. Our findings suggest that ALM use with trauma may reduce inflammatory injury and improve outcomes related to REBOA utilization.

Addition of neurological status to pediatric adjusted shock index to predict early mortality in trauma: A pediatric Trauma Quality Improvement Program analysis

INTRODUCTION

Pediatric adjusted shock index (SIPA) has demonstrated the ability to prospectively identify children at the highest risk for early mortality. The addition of neurological status to shock index has shown promise as a reliable triage tool in adult trauma populations. This study sought to assess the utility of combining SIPA with Glasgow Coma Scale (GCS) for predicting early trauma-related outcomes.

METHODS

Retrospective review of the 2017 Trauma Quality Improvement Program Database was performed for all severely injured patients younger than 18 years old. Pediatric adjusted shock index and reverse SIPA × GCS (rSIG) were calculated. Age-specific cutoff values were derived for reverse shock index multiplied by GCS (rSIG) and compared with their SIPA counterparts for early mortality assessment using area under the receiver operating characteristic curve analyses.

RESULTS

A total of 10,389 pediatric patients with an average age of 11.4 years, 67% male, average Injury Severity Score of 24.1, and 4% sustaining a major penetrating injury were included in the analysis. The overall mortality was 9.3%. Furthermore, 32.1% of patients displayed an elevated SIPA score, while only 27.5% displayed a positive rSIG. On area under the receiver operating characteristic curve analysis, rSIG was found to be superior to SIPA as a predictor for in hospital mortality with values of 0.854 versus 0.628, respectively.

CONCLUSION

Reverse shock index multiplied by GCS more readily predicted in hospital mortality for pediatric trauma patients when compared with SIPA. These findings suggest that neurological status should be an important factor during initial patient assessment. Further study to assess the applicability of rSIG for expanded trauma-related outcomes in pediatric trauma is necessary.

LEVEL OF EVIDENCE

Prognostic study, level IV.

A Surgeon's Guide to Machine Learning

Machine learning (ML) represents a collection of advanced data modeling techniques beyond the traditional statistical models and tests with which most clinicians are familiar. While a subset of artificial intelligence, ML is far from the science fiction impression frequently associated with AI. At its most basic, ML is about pattern finding, sometimes with complex algorithms. The advanced mathematical modeling of ML is seeing expanding use throughout healthcare and increasingly in the day-to-day practice of surgeons. As with any new technique or technology, a basic understanding of principles, applications, and limitations are essential for appropriate implementation. This primer is intended to provide the surgical reader an accelerated introduction to applied ML and considerations in potential research applications or the review of publications, including ML techniques.

Stemming the Tide of Opioid Addiction-Dramatic Reductions in Postoperative Opioid Requirements Through Preoperative Education and a Standardized Analgesic Regimen

INTRODUCTION

Surgery is a known gateway to opioid use that may result in long-term morbidity. Given the paucity of evidence regarding the appropriate amount of postoperative opioid analgesia and variable prescribing education, we investigated prescribing habits before and after institution of a multimodal postoperative pain management protocol.

MATERIALS AND METHODS

Laparoscopic appendectomies, laparoscopic cholecystectomies, inguinal hernia repairs, and umbilical hernia repairs performed at a tertiary military medical center from 01 October 2016 until 30 September 2017 were examined. Prescriptions provided at discharge, oral morphine equivalents (OME), repeat prescriptions, and demographic data were obtained. A pain management regimen emphasizing nonopioid analgesics was then formulated and implemented with patient education about expected postoperative outcomes. After implementation, procedures performed from 01 November 2017 until 28 February 2018 were then examined and analyzed. Additionally, a patient satisfaction survey was provided focusing on efficacy of postoperative pain control.

RESULTS

Preprotocol, 559 patients met inclusion criteria. About 97.5% were provided an opioid prescription, but prescriptions varied widely (256 OME, standard deviation [SD] 109). Acetaminophen was prescribed often (89.5%), but nonsteroidal anti-inflammatory drug (NSAID) prescriptions were rare (14.7%). About 6.1% of patients required repeat opioid prescriptions. After implementation, 181 patients met inclusion criteria. Initial opioid prescriptions decreased 69.8% (77 OME, SD 35; P < 0.001), while repeat opioid prescriptions remained statistically unchanged (2.79%; P = 0.122). Acetaminophen prescribing rose to 96.7% (P = 0.002), and NSAID utilization increased to 71.0% (P < 0.001). Postoperative survey data were obtained in 75 patients (41.9%). About 68% stated that they did not use all of the opioids prescribed and 81% endorsed excellent or good pain control throughout their postoperative course.

CONCLUSIONS

Appropriate preoperative counseling and utilization of nonopioid analgesics can dramatically reduce opioid use while maintaining high patient satisfaction. Patient-reported data suggest that even greater reductions may be possible.

Safety code blue! Assessing the use of blue surgical sterilization wrap for homemade respirator masks during the COVID-19 crisis

The use of surgical sterilization wrap for respirator masks during the COVID-19 crisis has become a popularized personal protective equipment alternative option due to claims supporting its ability to meet N95 standards. This study sought to assess these claims using standardized filter testing. The tested material failed to meet N95 standards and suggests its use may place medical personnel at increased risk of harm when managing COVID-19 patients.

Dynamic trend or static variable: Shock Index Pediatric-Adjusted (SIPA) in warzone trauma

BACKGROUND

Civilian studies suggest that trending Shock-Index Pediatric Adjusted(SIPA) values can prove useful in the prediction of trauma outcomes. The purpose of this study was to evaluate the relationship between trends in SIPA and outcomes in pediatric warzone trauma.

METHODS

Retrospective review of the Department of Defense Trauma Registry from 2008 to 2015, including all patients age ≤17years. SIPA was calculated both pre-hospital and upon arrival, then classified as "normal" or "abnormal" based upon previously validated thresholds. Patients were stratified into groups based on the trend of their SIPA (1-normal to normal, 2-normal to abnormal, 3-abnormal to normal, 4-abnormal to abnormal). Key outcomes including ICU admission, severe injury, mechanical ventilation, and mortality were then compared between groups.

RESULTS

669 patients were included, mean ISS 12 ± 10. The most common mechanism of injury was blast (46.5%). Overall, 43% were stratified into Group 1, 13.9% into Group 2, 14.8% into Group 3, and 28.0% into Group 4. Those patients with a persistently abnormal SIPA (Group 4) had significantly increased incidence of severe injury, ICU admission, need for mechanical ventilation, and mortality.

CONCLUSION

Trends in SIPA may be used to predict trauma outcomes for children injured in warzones, with persistently abnormal values associated with worse outcomes overall.

Pediatric adjusted reverse shock index multiplied by Glasgow Coma Scale as a prospective predictor for mortality in pediatric trauma

INTRODUCTION

Shock index and its pediatric adjusted derivative (pediatric age-adjusted shock index [SIPA]) have demonstrated utility as prospective predictors of mortality in adult and pediatric trauma populations. Although basic vital signs provide promise as triage tools, factors such as neurologic status on arrival have profound implications for trauma-related outcomes. Recently, the reverse shock index multiplied by Glasgow Coma Scale (GCS) score (rSIG) has been validated in adult trauma as a tool combining early markers of physiology and neurologic function to predict mortality. This study sought to compare the performance characteristics of rSIG against SIPA as a prospective predictor of mortality in pediatric war zone injuries.

METHODS

Retrospective review of the Department of Defense Trauma Registry, 2008 to 2016, was performed for all patients younger than 18 years with documented vital signs and GCS on initial arrival to the trauma bay. Optimal age-specific cutoff values were derived for rSIG via the Youden index using receiver operating characteristic analyses. Multivariate logistic regression was performed to validate accuracy in predicting early mortality.

RESULTS

A total of 2,007 pediatric patients with a median age range of 7 to 12 years, 79% male, average Injury Severity Score of 11.9, and 62.5% sustaining a penetrating injury were included in the analysis. The overall mortality was 7.1%. A total of 874 (43.5%) and 685 patients (34.1%) had elevated SIPA and pediatric rSIG scores, respectively. After adjusting for demographics, mechanism of injury, initial vital signs, and presenting laboratory values, rSIG (odds ratio, 4.054; p = 0.01) was found to be superior to SIPA (odds ratio, 2.742; p < 0.01) as an independent predictor of early mortality.

CONCLUSION

Reverse shock index multiplied by GCS score more accurately identifies pediatric patients at highest risk of death when compared with SIPA alone, following war zone injuries. These findings may help further refine early risk assessments for patient management and resource allocation in constrained settings. Further validation is necessary to determine applicability to the civilian population.

LEVEL OF EVIDENCE

Prognostic study, level IV.

Validation of a novel partial resuscitative endovascular balloon occlusion of the aorta device in a swine hemorrhagic shock model: Fine tuning flow to optimize bleeding control and reperfusion injury

OBJECTIVES

Partial restoration of aortic flow during resuscitative endovascular balloon occlusion of the aorta (REBOA) is advocated by some to mitigate distal ischemia. Our laboratory has validated the mechanics and optimal partial REBOA (pREBOA) flow rates using a prototype device. We hypothesize that pREBOA will increase survival when compared with full REBOA (fREBOA) in prolonged nonoperative management of hemorrhagic shock.

METHODS

Twenty swine underwent placement of aortic flow probes, zone 1 REBOA placement, and 20% blood volume hemorrhage. They were randomized to either solid organ or abdominal vascular injury. The pREBOA arm (10 swine) underwent full inflation for 10 minutes and then deflation to a flow rate of 0.5 L/min for 2 hours. The fREBOA arm (10 swine) underwent full inflation for 60 minutes, followed by deflation/resuscitation. The primary outcome is survival, and secondary outcomes are serologic/pathologic signs of ischemia-reperfusion injury and quantity of hemorrhage.

RESULTS

Two of 10 swine survived in the fREBOA group (2/5 solid organ injury; 0/5 abdominal vascular injury), whereas 7 of 10 swine survived in the pREBOA group (3/5 solid organ injury, 4/5 abdominal vascular injury). Survival was increased (p = 0.03) and hemorrhage was higher in the pREBOA group (solid organ injury, 1.36 ± 0.25 kg vs. 0.70 ± 0.33 kg, p = 0.007; 0.86 ± 0.22 kg vs. 0.71 ± 0.28 kg, not significant). Serum evidence of ischemia was greater with fREBOA, but this was not significant (e.g., lactate, 16.91 ± 3.87 mg/dL vs. 12.96 ± 2.48 mg/dL at 120 minutes, not significant). Swine treated with pREBOA that survived demonstrated trends toward lower alanine aminotransferase, lower potassium, and higher calcium. The potassium was significantly lower in survivors at 60 minutes and 90 minutes time points (5.97 ± 0.60 vs. 7.53 ± 0.90, p = 0.011; 6.67 ± 0.66 vs. 8.15 ± 0.78, p = 0.029). Calcium was significantly higher at 30 minutes, 60 minutes, and 90 minutes (8.56 ± 0.66 vs. 7.50 ± 0.40, p = 0.034; 8.63 ± 0.62 vs. 7.15 ± 0.49, p = 0.019; 8.96 ± 0.64 vs. 7.00, p = 0.028).

CONCLUSION

Prolonged pREBOA at a moderate distal flow rate provided adequate hemorrhage control, improved survival, and had evidence of decreased ischemic injury versus fREBOA. Prophylactic aggressive calcium supplementation may have utility before and during the reperfusion phase.

Neural ensemble reactivation in rapid eye movement and slow-wave sleep coordinate with muscle activity to promote rapid motor skill learning

Neural activity patterns of recent experiences are reactivated during sleep in structures critical for memory storage, including hippocampus and neocortex. This reactivation process is thought to aid memory consolidation. Although synaptic rearrangement dynamics following learning involve an interplay between slow-wave sleep (SWS) and rapid eye movement (REM) sleep, most physiological evidence implicates SWS directly following experience as a preferred window for reactivation. Here, we show that reactivation occurs in both REM and SWS and that coordination of REM and SWS activation on the same day is associated with rapid learning of a motor skill. We performed 6 h recordings from cells in rats' motor cortex as they were trained daily on a skilled reaching task. In addition to SWS following training, reactivation occurred in REM, primarily during the pre-task rest period, and REM and SWS reactivation occurred on the same day in rats that acquired the skill rapidly. Both pre-task REM and post-task SWS activation were coordinated with muscle activity during sleep, suggesting a functional role for reactivation in skill learning. Our results provide the first demonstration that reactivation in REM sleep occurs during motor skill learning and that coordinated reactivation in both sleep states on the same day, although at different times, is beneficial for skill learning. This article is part of the Theo Murphy meeting issue 'Memory reactivation: replaying events past, present and future'.

Senior surgical resident autonomy and teaching assistant cases: A prospective observational study

INTRODUCTION

Teaching assistant (TA) cases allow senior residents (SR) to gain autonomy. We compared the safety profiles of TA cases performed under direct vs. indirect staff supervision.

METHODS

Prospective observational study of operative cases where a SR served as the TA between 7/2014-6/2017 (n = 161). Patient/operative characteristics, 30-day outcomes, and SR survey data were compared by level of supervision.

RESULTS

Case mix included 68 laparoscopic appendectomies (42%), 49 laparoscopic cholecystectomies (30%), 10 I&Ds (6%), 10 umbilical hernia repairs (6%), 4 port placements (3%), and 11 others. Indirectly supervised cases were shorter (61 vs. 76 min, p < 0.01), with less blood loss (11 vs. 24 ml, p < 0.05), and lower conversion rates (0% vs. 5.7%, p < 0.05). Perceived difficulty was high in 20% of cases with indirect vs. 49% with direct supervision (p < 0.01). Mean SR comfort was high (4.4 vs. 4.6 out of 5) regardless of level of staff supervision. 30-day complications did not differ for indirect vs. direct supervision (all p = NS).

DISCUSSION

Carefully selected TA cases offer SRs opportunities to practice autonomy without sacrificing operative time or patient safety.

An Evaluation of a Novel Medical Device Versus Standard Interventions in the Treatment of Tension Pneumothorax in a Swine Model (Sus scrofa)

INTRODUCTION

Tension pneumothorax is a common cause of preventable death in trauma. Needle decompression is the traditional first-line intervention but has high failure rates. We sought to evaluate the effectiveness and expedience of needle thoracostomy, surgical tube thoracostomy, and Reactor™ thoracostomy - a novel spring-loaded trocar insertion device.

MATERIALS AND METHODS

Yorkshire swine underwent controlled thoracic insufflation to create tension pneumothorax physiology for device comparison. Additional experiments were performed by increasing insufflation pressures to achieve pulseless electrical activity. Intervention was randomized to needle thoracostomy (14 gauge), tube thoracostomy (32Fr), or Reactor™ thoracostomy (36Fr). Air leak was simulated throughout intervention with 40-80 mL/kg/min insufflation. Intrathoracic pressure monitoring and hemodynamic parameters were obtained at 1 and 5 minutes.

RESULTS

Tension physiology and tension-induced pulseless electrical activity were created in all iterations. Needle thoracostomy (n = 28) was faster at 7.04 ± 3.04 seconds than both Reactor thoracostomy (n = 32), 11.63 ± 5.30 (p < 0.05) and tube thoracostomy (n = 32), 27.06 ± 10.73 (p < 0.01); however, Reactor™ thoracostomy was faster than tube thoracostomy (p < 0.001). Physiological decompression was achieved in all patients treated with Reactor™ and tube thoracostomy, but only 14% of needle thoracostomy. Cardiac recovery to complete physiologic baseline occurred in only 21% (6/28) of those treated with needle thoracostomy whereas Reactor™ or tube thoracostomy demonstrated 88% (28/32) and 94% (30/32) response rates. When combined, needle thoracostomy successfully treated tension pneumothorax in only 4% (1/28) of subjects as compared to 88% (28/32) with Reactor™ thoracostomy and 94% (30/32) with tube thoracostomy (p < 0.01).

CONCLUSIONS

Needle thoracostomy provides a rapid intervention for tension pneumothorax, but is associated with unacceptably high failure rates. Reactor™ thoracostomy was effective, expedient, and may provide a useful and technically simpler first-line treatment for tension pneumothorax or tension-induced pulseless electrical activity.

Lifesaving interventions in blackout conditions using night vision technology: Come to the dark side

BACKGROUND

During military combat operations and civilian night-time aeromedical transport, medical providers are frequently required to perform lifesaving interventions (LSIs) in low-light environments. Because definitive surgical care is often delayed until a white light environment is permissible, we sought to determine if night optical device (NOD) technology could enable surgical capabilities in blackout conditions.

METHODS

Using a crossover design, six surgeons performed 11 different procedures on six swine, three in normal light conditions (LC) and 3 in blackout conditions (BC) using two-chamber NODs after familiarization with the procedures in both conditions on manikins. Successful completion and procedural times were compared between groups.

RESULTS

Blackout conditions were confirmed with ambient light reading of 0.2 lux during BC versus 3962.9 lux for LC (p < 0.001). There were no significant differences in success rates for any procedure. There were no differences in operative times between BC and LC for extremity tourniquet placement, femoral artery cut-down and clamping, resuscitative thoracotomy, or percutaneous resuscitative endovascular balloon occlusion of the aorta placement. The following procedures took significantly longer in BC vs. LC: Focused Assessment with Sonography for Trauma examination (98 seconds vs. 62 seconds), peripheral IV placement (140 seconds vs. 35 seconds), intraosseous access (51 seconds vs. 26 seconds), jugular vein cut-down and access (237 seconds vs. 104 seconds), laparotomy and packing (71 seconds vs. 51 seconds), stapled splenectomy (137 seconds vs. 74 seconds), resuscitative endovascular balloon occlusion of the aorta placement via cutdown (1,008 seconds vs. 338 seconds), and cricothyroidotomy (177 seconds vs. 109 seconds) (all p < 0.05).

CONCLUSION

Lifesaving interventions can be safely and effectively performed in blackout conditions using NODs, although increased difficulty with select procedure types was identified. Focused training and technological improvements to currently available devices are needed.

LEVEL OF EVIDENCE

Basic science.

Microdermal Implants Show No Effect on Surrounding Tissue During Surgery With Electrocautery

BACKGROUND

Microdermal implants are an increasingly popular form of body jewelry. The potential for electrical conduction burn at the site of metal jewelry left in situ during electrosurgery has prompted surgical societies to recommend routine removal before surgery. To date, however, there is a lack of evidence to support this practice. We assessed in vivo thermal effect and tissue damage around implants during and after electrocautery.

MATERIALS AND METHODS

Stainless steel microdermal anchors were surgically implanted into four swine. After allowing for initial healing, negative controls were excised and evaluated. An electrocautery grounding pad was placed 2 cm caudal to the implant. Continuous electrocautery (coagulation/30 W) for 30 s was applied to the skin 2 cm cranial to the implant. Surface skin temperature was recorded during electrocautery using thermal imaging. Tissue damage was assessed by gross examination and histologic evaluation. The same procedure was then performed to the contralateral nonimplanted side as a sham control.

RESULTS

Electrocoagulation raised skin temperature around the electrocautery tip 27.7°C (T_max 64.8°C). Skin temperature around the dermal implant rose 1.58°C (T_max 38.6°C) compared with 2.03°C (T_max 39.2°C) in the nonimplanted control skin (P = 0.627). Skin temperatures at implanted and control sites showed no statistical difference at any recorded time interval. Histologic review of excised tissue samples showed no evidence of thermal injury.

CONCLUSIONS

Metallic implants appear to have no effect on skin temperature during the use of electrocautery even when in close proximity to both the electrocautery pen and return pad. Aggressive steps to remove microdermal implants before surgery may be unnecessary.

Mobile forward-looking infrared technology allows rapid assessment of resuscitative endovascular balloon occlusion of the aorta in hemorrhage and blackout conditions

INTRODUCTION

Objective assessment of final resuscitative endovascular balloon occlusion of the aorta (REBOA) position and adequate distal aortic occlusion is critical in patients with hemorrhagic shock, especially as feasibility is being increasingly investigated in the prehospital setting. We propose that mobile forward-looking infrared (FLIR) thermal imaging is a fast, reliable, and noninvasive method to assess REBOA position and efficacy in scenarios applicable to battlefield and prehospital care.

METHODS

Ten swine were randomized to a 40% hemorrhage group (H, n = 5) or nonhemorrhage group (NH, n = 5). Three experiments were completed after Zone I placement of a REBOA catheter. Resuscitative endovascular balloon occlusion of the aorta was deployed for 30 minutes in all animals followed by randomized continued deployment versus sham in both light and blackout conditions. Forward-looking infrared images and hemodynamic data were obtained. Images were presented to 62 blinded observers for assessment of REBOA inflation status.

RESULTS

There was no difference in hemodynamic or laboratory values at baseline. The H group was significantly more hypotensive (mean arterial pressure 44 vs. 60 mm Hg, p < 0.01), vasodilated (systemic vascular resistance 634 vs. 938dyn·s/cm, p = 0.02), and anemic (hematocrit 12 vs. 23.2%, p < 0.01). Hemorrhage group animals remained more hypotensive, anemic, and acidotic throughout all three experiments. There was a significant difference in the temperature change (ΔTemp) measured by FLIR between animals with REBOA inflated versus not inflated (5.7°C vs. 0.7°C, p < 0.01). The H and NH animals exhibited equal magnitudes of ΔTemp in both inflated and deflated states. Blinded observer analysis of FLIR images correctly identified adequate REBOA inflation and aortic occlusion 95.4% at 5 minutes and 98.8% at 10 minutes (positive predictive value at 5 minutes = 99% and positive predictive value at 10 minutes = 100%).

CONCLUSIONS

Mobile thermal imaging is an easy, rapid, and reliable method for assessing distal perfusion after occlusion by REBOA. Smartphone-based FLIR technology allows for confirmation of adequate REBOA placement at the point of care, and performance was not degraded in the setting of major hemorrhage or blackout conditions.

Coronary sinus and atrioventricular groove avulsion after motor vehicle crash

Simultaneous cardiac and pericardial rupture from blunt chest trauma is a highly lethal combination with rarely reported survival. We report of a case of young patient with a right atrioventricular groove injury, pericardial rupture and a unique description of a coronary sinus avulsion following blunt chest trauma. Rapid recognition of this injury is crucial to patient survival, but traditional diagnostic adjuncts such as ultrasound, echocardiography and computed tomography are often unhelpful. Successful repair of these injuries requires high suspicion of injury, early cardiac surgery involvement of and possible even placement of the patient on cardiopulmonary bypass.

Rapid visual stimulation increases extrasynaptic glutamate receptor expression but not visual-evoked potentials in the adult rat primary visual cortex

The model most used to study synaptic plasticity, long-term potentiation (LTP), typically employs electrical stimulation of afferent fibers to induce changes in synaptic strength. It would be beneficial for understanding the behavioral relevance of LTP if a model could be developed that used more naturalistic stimuli. Recent evidence suggests that the adult visual cortex, previously thought to have lost most of its plasticity once past the critical period, is in fact capable of LTP-like changes in synaptic strength in response to sensory manipulations alone. In a preliminary study, we used a photic tetanus (PT; flashing checkerboard stimulus) to induce an enhancement of the visual-evoked potential (VEP) in the primary visual cortex of anesthetised adult rats. In the present study, we sought to compare the mechanisms of this novel sensory LTP with those of traditional electrical LTP. Unexpectedly, we found that sensory LTP was not induced as reliably as we had observed previously, as manipulations of several parameters failed to lead to significant potentiation of the VEP. However, we did observe a significant increase in visual cortex glutamate receptor expression on the surface of isolated synapses following the PT. Both AMPA receptor expression and N-methyl-d-aspartate (NMDA) receptor subunit expression were increased, specifically in extrasynaptic regions of the membrane, in PT animals. These results provide biochemical confirmation of the lack of change in the VEP in response to PT, but suggest that PT may prime synapses for strengthening upon appropriate subsequent activation, through the trafficking of glutamate receptors to the cell surface.

Safety of bedside percutaneous tracheostomy in the critically ill: evaluation of more than 3,000 procedures

BACKGROUND

Bedside percutaneous dilational tracheostomy has been demonstrated to be equivalent to open tracheostomy. At our institution, percutaneous dilational tracheostomy without routine bronchoscopy is our preferred method. My colleagues and I hypothesized that our 10-year percutaneous dilational tracheostomy experience would demonstrate that the technique is safe with low complication rates, even in obese patient populations.

STUDY DESIGN

We conducted a retrospective review of all bedside percutaneous dilational tracheostomy performed by the Division of Trauma and Surgical Critical Care faculty from 2001 to 2011, excluding patients younger than 18 years of age. All major airway complications and procedure-related deaths were evaluated during the early (≤48 hours postprocedure), intermediate (in hospital), and late (after discharge) periods. Incidence of post-tracheostomy stenosis was also evaluated.

RESULTS

There were 3,162 percutaneous dilational tracheostomies performed during the study period. Mean body mass index was 28 (16% with body mass index ≥35), mean Injury Severity Score was 32, and mean APACHE II score was 19. Major airway complications occurred in 12 (0.38%) patients, accounting for 5 (0.16%) deaths. Early major complications included 3 airway losses and 1 bleeding event requiring formal exploration with procedure-related deaths occurring in 3 patients. Intermediate major complications included 2 tube occlusion/dislodgement events with 2 related deaths. Late complications included 5 (0.16%) cases of tracheal stenosis requiring intervention without associated deaths.

CONCLUSIONS

Bedside percutaneous dilational tracheostomy is safe across a broad critically ill patient population. The safety of this technique, even in the obese population, is demonstrated by its low complication rate. Routine bronchoscopic guidance is not necessary. Specially trained procedure nurse and process improvement programs contribute to the safety and efficacy of this procedure.

Regulation of PIDD auto-proteolysis and activity by the molecular chaperone Hsp90

In response to DNA damage, p53-induced protein with a death domain (PIDD) forms a complex called the PIDDosome, which either consists of PIDD, RIP-associated protein with a death domain and caspase-2, forming a platform for the activation of caspase-2, or contains PIDD, RIP1 and NEMO, important for NF-κB activation. PIDDosome activation is dependent on auto-processing of PIDD at two different sites, generating the fragments PIDD-C and PIDD-CC. Despite constitutive cleavage, endogenous PIDD remains inactive. In this study, we screened for novel PIDD regulators and identified heat shock protein 90 (Hsp90) as a major effector in both PIDD protein maturation and activation. Hsp90, together with p23, binds PIDD and inhibition of Hsp90 activity with geldanamycin efficiently disrupts this association and impairs PIDD auto-processing. Consequently, both PIDD-mediated NF-κB and caspase-2 activation are abrogated. Interestingly, PIDDosome formation itself is associated with Hsp90 release. Characterisation of cytoplasmic and nuclear pools of PIDD showed that active PIDD accumulates in the nucleus and that only cytoplasmic PIDD is bound to Hsp90. Finally, heat shock induces Hsp90 release from PIDD and PIDD nuclear translocation. Thus, Hsp90 has a major role in controlling PIDD functional activity.

Hypoxemic versus normoxemic reperfusion in a large animal model of severe ischemia-reperfusion injury

BACKGROUND

Prior studies have suggested a significant benefit of using deliberate hypoxemia to reperfuse ischemic tissue beds, primarily by reducing free radical injury. We sought to examine the effects of a hypoxemic reperfusion strategy in a large animal model of severe truncal ischemia.

MATERIALS AND METHODS

Adult swine were subjected to 30 min of supraceliac aortic occlusion and randomized to two groups: normoxemia group (n = 9), with resuscitation at a pO2 >100 mmHg or hypoxemia group (n = 10), with initial resuscitation at a pO2 of 30-50. The two groups were compared using physiologic parameters, fluid and pressor requirements, inflammatory and oxidative markers, and histologic analysis of end-organ injury.

RESULTS

All animals developed significant hemodynamic instability immediately upon reperfusion. Average mean arterial pressure at baseline rose significantly after 30 min of cross-clamp (76.8 versus 166.3 mmHg, P < 0.001). Upon reperfusion, all animals required epinephrine and fluids to maintain mean arterial pressure (MAP) greater than 60 mmHg. After stabilization, the two groups were similar in terms of central and pulmonary hemodynamics. The hypoxemic group required more mean total epinephrine (18.35 mg versus 5.28 mg, P < 0.01) with no significant difference in total fluid volume (hypoxemic 9111 ml versus 8420 mL, P = 0.730). The hypoxemic group demonstrated a more severe metabolic acidosis at all time intervals after reperfusion (pH 7.02 versus 7.16 and lactate 17 versus 13, both P < 0.01). There was no difference in malondialdehyde concentration between the two groups, but the hypoxemic group had a higher antioxidant reductive capacity at all intervals after 30 min of reperfusion (0.23 versus 0.27 uM, P = 0.03). While there was significant end-organ damage on pathologic examination of all liver and kidney specimens (mean severity of injury 1.59 and 1.76, respectively, on a scale of 1-3), there was no significant difference between the two groups.

CONCLUSIONS

A hypoxemic reperfusion strategy in this large animal model failed to demonstrate any significant clinical benefit. Although there was chemical evidence of improved antioxidant capacity with hypoxemia, it was associated with more instability, metabolic and physiologic derangements, and no evidence of end-organ protection.

Incidence of low vitamin A levels and ocular symptoms after Roux-en-Y gastric bypass

BACKGROUND

Previous reports have demonstrated a significant incidence of fat-soluble vitamin deficiency after bariatric surgery. The purpose of the present study was to determine the incidence of vitamin A deficiency after Roux-en-Y gastric bypass and to correlate the laboratory findings with ocular symptoms potentially related to vitamin A deficiency.

METHODS

All patients who had undergone Roux-en-Y gastric bypass were invited to participate in a nutritional screening. The patients completed a detailed survey concerning ocular symptoms and had their vitamin A level evaluated.

RESULTS

A low vitamin A level was identified in 7 (11%) of 64 RYBG patients. Ocular xerosis was present in 18 patients (27%), with night vision changes reported in 45 (68%). Visual disturbances were present in 7 patients (11%) found to have low vitamin A levels, with hypovitaminosis A present in 22% of patients with xerosis (P <.05).

CONCLUSION

Low vitamin A levels and frequent ocular complaints that might be associated with decreased vitamin A are common findings in the post-RYBG patient population. Additional study is needed to assess the role of routine vitamin A screening and replacement in the postbariatric surgery patient.

Colonic ischemia complicating open vs endovascular abdominal aortic aneurysm repair

OBJECTIVE

Colonic ischemia (CI) is a known complication of both open abdominal aortic aneurysm (AAA) repair and endovascular aneurysm repair (EVAR). Despite a relatively low incidence of 1% to 6%, the associated morbidity and mortality are high. We sought to analyze factors that affect the development of CI on the basis of type of repair as well as associated outcomes from a large nationwide database.

METHODS

All admissions undergoing AAA repair were selected from the 2003 and 2004 Nationwide Inpatient Sample. Univariate and logistic regression analyses were used to compare outcome measures and identify independent predictors of development of colonic ischemic complications.

RESULTS

We identified 89,967 admissions for AAA repair (mean age, 69.9 years). Open elective repair was performed in 49% of cases, elective EVAR in 41%, and ruptured aneurysm repair in 9%. The overall incidence of CI was 2.2% (1941 cases); however, the incidence for specific procedures was significantly higher after repair of ruptured aneurysm (8.9%) and open elective repair (1.9%) than after EVAR (0.5%; both P < .001). Patients who developed CI were at increased risk for mortality (37.8% vs 6.7%), had longer hospital stays (21.5 vs 8.1 days), incurred higher hospital charges ($182,000 vs $77,000), and were less likely to be discharged home from hospital (36% vs 71%; all P < .001). Independent predictors of development of CI included ruptured aneurysm (odds ratio [OR] = 6.4), female gender (OR = 1.6) and, in the setting of elective repair, open operation (OR = 3.1). CI was found to be a strong independent predictor of mortality in evaluations of both the entire cohort (OR = 4.5) and the elective open repair and EVAR (OR = 2.4) subgroups.

CONCLUSIONS

CI is significantly more common after open AAA repair and is associated with increased morbidity and a two- to fourfold increase in mortality.

Long-term depression and associativity in rat primary motor cortex following thalamic stimulation

Associativity is an attractive property of LTP in terms of its possible mechanism as a model for memory storage. In this study, we compare the effects of homosynaptic vs. associative stimulation on the induction of LTP and LTD in the neocortex of freely behaving rats. Using a callosal input to the motor cortex as a 'strong' input (one that potentiates reliably following homosynaptic stimulation), we paired activity of this pathway with a 'weak' thalamocortical pathway (one that does not potentiate when stimulated homosynaptically). Surprisingly, homosynaptic HFS caused a lasting depression of the field EPSP in the thalamocortical pathway. Analysis of this effect revealed that it was largely polysynaptic. Associative HFS (HFS applied to both pathways) not only failed to induce an LTP effect in the thalamocortical pathway, it increased the magnitude of the depression. Associative HFS did, however, facilitate LTP induction in the 'strong' callosal pathway. When comparing the effects of homosynaptic and associative LTD induction (HFS on one pathway anticorrelated with LFS on the other), we found that both protocols induced a similar magnitude of depression. These results show that HFS applied to the thalamocortical pathway causes a depression and this depression is enhanced, not reversed, by associative pairing with a strong input.

Bronchoscopy in the Blast Injury Patient

HYPOTHESIS

Delayed presentation of secondary airway injury is a significant clinical entity following blast injury.

DESIGN

Retrospective review.

SETTING

Combat Support Hospital, Operation Iraqi Freedom.

PATIENTS

Twenty-three blast injury patients with bronchoscopic evidence of secondary airway injury.

MAIN OUTCOME MEASURES

Symptom development and time frame, bronchoscopic findings, and requirement for mechanical ventilation.

RESULTS

All of the 23 patients presented within 12 hours of injury. Eleven patients (48%) arrived at the hospital after prior endotracheal intubation. The majority (17 patients [74%]) of patients had no carbonaceous sputum, singed nasal hair, or thoracic trauma that would suggest possible airway injury. Bronchoscopy revealed mucosal erythema and edema in 16 (70%) of the patients, 6 (23%) had additional airway carbonaceous deposits, and 5 (21%) had normal findings on initial bronchoscopy. Eight patients (35%) initially breathing spontaneously and demonstrating no thoracic trauma required intubation within 12 hours of admission owing to impending loss of airway patency. Bronchoscopy revealed significant airway edema (>50% patency loss) in 6 (75%) of these 8 patients, with additional carbonaceous deposits in 3 patients (38%). Patients requiring delayed intubation had a significantly greater respiratory rate on initial examination.

CONCLUSIONS

Manifestation of secondary airway injury may be delayed up to 12 hours following blast injury. We believe that blast injury patients should be observed for at least 18 hours after injury or until edema has resolved and in a setting amenable to emergent airway support and rapid bronchoscopic evaluation at the earliest indication of possible airway compromise.

Ventilator-Associated Pneumonia After Combined Burn and Trauma Is Caused by Associated Injuries and Not the Burn Wound

An increased risk of ventilator-associated pneumonia (VAP) has previously been demonstrated in trauma patients urgently intubated in the prehospital (ie, field) and emergency department (ED) settings. This study investigated the impact of urgent intubation on subsequent VAP in patients who sustained both a burn injury and a traumatic injury. We undertook a retrospective review of both trauma registry data and medical records for all patients with combined thermal and traumatic injuries admitted to a single verified burn center and level I trauma center. Patients undergoing field or ED intubation during the 5-year period ending December 2002 were identified and studied. Data abstracted included admission demographics and vital signs, presence of inhalation injury, location at the time of intubation, presence of associated injury, percentage TBSA burn, hospital and intensive care unit length of stay, and hospital day of VAP diagnosis. Seventy-eight of the 3388 patients (2.3%) admitted during the study period sustained a combination of burn wounds and trauma and underwent urgent field or ED intubation. The majority of patients were men (71%), with a mean age of 46 +/- 24 years. There was one failed oral intubation, which required cricothyroidotomy. The location of the patient at the time of intubation was ED, 66%; burn center ED, 17%; and field, 17%. Eighty percent of all patients were diagnosed with an inhalation injury. VAP was diagnosed in 39 patients (50%), with a mean time to diagnosis of 10 +/- 9 days. TBSA burn, smoke inhalation, and time (in days) to diagnosis of VAP were not independent risk factors for the occurrence of pneumonia in any of the 3 groups. However, those intubated at the initial ED were more likely to develop VAP (P = .028) compared to those intubated in the field or in the burn center. The incidence of associated injuries was significantly greater (P < .0001) in the initial ED group. Only a small percentage of burn patients also sustain blunt trauma. VAP occurs in 50% of the patients requiring urgent intubation. Independent risk factors appear to be intubation at an initial ED before transfer and associated injuries.

Ventilator-associated pneumonia, like real estate: location really matters

INTRODUCTION

Previous work has demonstrated an increased risk of ventilator-associated pneumonia (VAP) in trauma patients after prehospital (field) intubation as compared with emergency department (ED) intubations. However, this population was not compared with patients intubated as inpatients, making data interpretation difficult. We sought to further examine predictors for the development of VAP after trauma.

METHODS

A 10-year retrospective review of all patients mechanically ventilated greater than 24 hours after injury was performed.

RESULTS

In all, 1,628 patients were identified, of which 1,213 (75%) were intubated as inpatients and 415 were emergently intubated (353 ED, 62 field). Overall, those intubated emergently were younger (p = 0.03) and less injured as seen by higher Glasgow Coma Scale scores (p = 0.0002), lower Injury Severity Scores (p = 0.01) and higher Revised Trauma Scores (p < 0.0001). Despite a lower injury severity, those patients emergently intubated were more likely to develop pneumonia as 22% of ED intubations and 15% of field intubations developed pneumonia, as compared with the inpatient rate of 6.5%. Pneumonia after field intubation was more likely to be community-acquired (p < 0.0001) with a significantly lower percentage of infecting enteric gram-negative rods (p < 0.0001) as compared with the inpatient and ED groups. Forward logistic regression analysis (with VAP = 1) identified inpatient intubation as protective against VAP (odds ratio 0.28, 95% CI = 0.2-0.4). Backwards logistic regression analysis further identified both field airway (odds ratio 2.29, 95% CI = 1.1-4.9) and ED airway (odds ratio 3.61, 95% CI = 2.5-5.2) as predictive of VAP.

CONCLUSIONS

Compared with a population of trauma patients as inpatients, and excluding those patients mechanically ventilated less than 24 hours, patients intubated in the ED or field have a higher incidence of pneumonia, despite equivalent or lower injury severity.

Ventilator-associated pneumonia in injured patients: do you trust your Gram's stain?

BACKGROUND

The results of sputum or bronchoalveolar lavage (BAL) fluid Gram's stain have been used to guide presumptive antibiotic therapy for ventilator-associated pneumonia (VAP) in injured patients, despite reported variability in sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. Our aim was to evaluate the utility of Gram's stain of BAL fluid in the diagnosis of VAP.

METHODS

We conducted a retrospective chart review of all mechanically ventilated trauma patients who developed pneumonia over a 5-year period in whom Gram's stain and final culture data were available.

RESULTS

One hundred fifty-five records with complete data sets were reviewed. VAP was diagnosed by Centers for Disease Control and Prevention criteria and confirmed by BAL and quantitative culture in all patients. Overall accuracy of Gram's stain in diagnosing VAP for any organism was 88% (137 true-positives). When assessed for the ability to predict pneumonia caused by a specific organism, the accuracy decreased significantly, with only 63% of Gram-negative VAPs and 72% of Gram-positive VAPs accurately identified by Gram's stain. However, the absence of Gram-positive organism of Gram's stain excludes Gram-positive VAP in 80% of patients.

CONCLUSION

All trauma patients should be covered presumptively for gram-negative organisms, as they encompass 70% of infections, but are not reliably identified by Gram's stain. As 88% of VAP can be identified by the presence of any organism on Gram's stain, it may be useful in the early diagnosis of VAP but cannot reliably be used to guide presumptive therapy.

Urgent airways after trauma: who gets pneumonia?

BACKGROUND

Several risk factors, including emergent intubation, severe head injury, shock, blunt trauma, and high severity of injury, have been identified as risk factors for the development of pneumonia after trauma. This study assesses the contribution of emergent intubation to the development of pneumonia after injury.

METHODS

A retrospective review of all trauma patients requiring intubation or cricothyroidotomy in the Emergency Department (ED) or in the pre-hospital area (field) over a 41/2 year period.

RESULTS

571 patients comprised the study population. Of these, 80% had airways established in the ED, while 20% were intubated in the field. Field intubation was associated with a lower Glasgow Coma Scale (GCS) score (p <0.0001) and more severe injury (p <0.0001), particularly to the chest and extremities.Twenty-five percent of the population developed pneumonia. Patients diagnosed with pneumonia were older (p=0.009), and had a higher ISS (p <0.0001), lower GCS score, (p <0.008), longer ICU and hospital length of stay (p < 0.0001). Injuries to the head, thorax and extremities were more common (p < 0.05) and more severe (p <0.05) in patients developing pneumonia. The incidence of pneumonia after field airway was significantly higher (35% versus 23%, p=0.048).Multiple logistic regression analysis identified field intubation, age, AIS-head, and AIS-extremity as independent risk factors for pneumonia.

CONCLUSION

Pre-hospital but not ED intubation is an independent risk factor for the development of post-traumatic pneumonia. Other predictors include the severity of injury, specifically head and extremity injuries.