Comparison of Outcome Tools Used to Test Mass-Casualty Algorithms in the Pediatric Population.

INTRODUCTION: Mass-casualty incident (MCI) algorithms are used to sort large numbers of patients rapidly into four basic categories based on severity. To date, there is no consensus on the best method to test the accuracy of an MCI algorithm in the pediatric population, nor on the agreement between different tools designed for this purpose. STUDY OBJECTIVE: This study is to compare agreement between the Criteria Outcomes Tool (COT) to previously published outcomes tools in assessing the triage category applied to a simulated set of pediatric MCI patients. METHODS: An MCI triage category (black, red, yellow, and green) was applied to patients from a pre-collected retrospective cohort of pediatric patients under 14 years of age brought in as a trauma activation to a Level I trauma center from July 2010 through November 2013 using each of the following outcome measures: COT, modified Baxt score, modified Baxt combined with mortality and/or length-of-stay (LOS), ambulatory status, mortality alone, and Injury Severity Score (ISS). Descriptive statistics were applied to determine agreement between tools. RESULTS: A total of 247 patients were included, ranging from 25 days to 13 years of age. The outcome of mortality had 100% agreement with the COT black. The "modified Baxt positive and alive" outcome had the highest agreement with COT red (65%). All yellow outcomes had 47%-53% agreement with COT yellow. "Modified Baxt negative and <24 hours LOS" had the highest agreement with the COT green at 89%. CONCLUSIONS: Assessment of algorithms for triaging pediatric MCI patients is complicated by the lack of a gold standard outcome tool and variability between existing measures.

Prehospital Disaster Triage Does Not Predict Pediatric Outcomes: Comparing the Criteria Outcomes Tool to Three Mass-Casualty Incident Triage Algorithms.

INTRODUCTION: It remains unclear which mass-casualty incident (MCI) triage tool best predicts outcomes for child disaster victims. STUDY OBJECTIVES: The primary objective of this study was to compare triage outcomes of Simple Triage and Rapid Treatment (START), modified START, and CareFlight in pediatric patients to an outcomes-based gold standard using the Criteria Outcomes Tool (COT). The secondary outcomes were sensitivity, specificity, under-triage, over-triage, and overall accuracy at each level for each MCI triage algorithm. METHODS: Singleton trauma patients under 16 years of age with complete prehospital, emergency department (ED), and in-patient data were identified in the 2007-2009 National Trauma Data Bank (NTDB). The COT outcomes and procedures were translated into ICD-9 procedure codes with added timing criteria. Gold standard triage levels were assigned using the COT based on outcomes, including mortality, injury type, admission to the hospital, and surgical procedures. Comparison triage levels were determined based on algorithmic depictions of the three MCI triage tools. RESULTS: A total of 31,093 patients with complete data were identified from the NTDB. The COT was applied to these patients, and the breakdown of gold standard triage levels, based on their actual clinical outcomes, was: 17,333 (55.7%) GREEN; 11,587 (37.3%) YELLOW; 1,572 (5.1%) RED; and 601 (1.9%) BLACK. CareFlight had the best sensitivity for predicting COT outcomes for BLACK (83% [95% confidence interval, 80%-86%]) and GREEN patients (79% [95% CI, 79%-80%]) and the best specificity for RED patients (89% [95% CI, 89%-90%]). CONCLUSION: Among three prehospital MCI triage tools, CareFlight had the best performance for correlating with outcomes in the COT. Overall, none of three tools had good test characteristics for predicting pediatric patient needs for surgical procedures or hospital admission.

Epidemiology of Prehospital Care at the San Diego (USA) - Tijuana (Mexico) International Border Crossing.

Introduction: San Diego has one of the busiest international land border crossings in the world. The epidemiology of prehospital care at the San Diego (California, USA)-Tijuana (Baja California, Mexico) border crossings are previously unreported. Investigators sought to describe prehospital care provided at the San Diego border crossings. Methods: This was a cross-sectional, retrospective data collection from April 2014 to March 2017 evaluating prehospital provider (PHP) contacts at 2 international border crossing addresses in San Diego. The 9-1-1 dispatch center and first response were provided by a single municipal fire agency with ambulance transportation provided by a contracting private agency. Patient dispatch data and electronic patient care records were queried for patient demographics, PHP arrival time, incident complaint, assessment narrative, and treatments provided. Natural language processing techniques were applied to map the narrative to the National Library of Medicine's Unified Medical Language System. Descriptive analysis was performed in the R software program. Results: A total of 6,261 PHP patient contacts were made at the 2 border crossings during the study period. 87% of the calls were at the San Ysidro border crossing compared to 13% at Otay Mesa. The population, composed of 50.8% males, had ages ranging from 0 days-103 years old, with a median age of 45 years old. There were 606 (9.7%) pediatric patients (<18 years) and 1,416 (22.6%) geriatric patients (>65 years). The top 3 incident complaints were respiratory distress (830, 10.8%), blunt trauma (827, 10.7%), and abdominal pain (814, 10.6%); and, the top 3 medications provided were oxygen (481, 7.7%), normal saline (393, 6.3%), and ondansetron (352, 5.6%). Conclusion: This was the first study of PHP assessment and care at the San Diego-Tijuana border crossings. We found a large diversity in patient ages. Respiratory distress and blunt trauma were the most frequent complaints and oxygen was the most frequent medication. The busiest day of the week was Sunday, and the busiest month of the year was July. Our newly described findings may assist EMS agencies with optimizing staff, equipment, and training at international border crossings.

A Novel Algorithm for Improving the Diagnostic Accuracy of Prehospital ST-Elevation Myocardial Infarction.

INTRODUCTION: ST-segment elevation myocardial infarction (STEMI) is a time-sensitive entity that has been shown to benefit from prehospital diagnosis by electrocardiogram (ECG). Current computer algorithms with binary decision making are not accurate enough to be relied on for cardiac catheterization lab (CCL) activation. HYPOTHESIS: An algorithmic approach is proposed to stratify binary STEMI computerized ECG interpretations into low, intermediate, and high STEMI probability tiers. METHODS: Based on previous literature, a four-criteria algorithm was developed to rule out/in common causes of prehospital STEMI false-positive computer interpretations: heart rate, QRS width, ST elevation criteria, and artifact. Prehospital STEMI cases were prospectively collected at a single academic center in Salt Lake City, Utah (USA) from May 2012 through October 2013. The prehospital ECGs were applied to the algorithm and compared against activation of the CCL by an emergency department (ED) physician as the outcome of interest. In addition to calculating test characteristics, linear regression was used to look for an association between number of criteria used and accuracy, and logistic regression was used to test if any single criterion performed better than another. RESULTS: There were 63 ECGs available for review, 39 high probability and 24 intermediate probability. The high probability STEMI tier had excellent test characteristics for ruling in STEMI when all four criteria were used, specificity 1.00 (95% CI, 0.59-1.00), positive predictive value 1.00 (0.91-1.00). Linear regression showed a strong correlation demonstrating that false-positives increased as fewer criteria were used (adjusted r-square 0.51; P <.01). Logistic regression showed no significant predictive value for any one criterion over another (P = .80). Limiting physician overread to the intermediate tier only would reduce the number of ECGs requiring physician overread by a factor of 0.62 (95% CI, 0.48-0.75; P <.01). CONCLUSION: Prehospital STEMI ECGs can be accurately stratified to high, intermediate, and low probabilities for STEMI using the four criteria. While additional study is required, using this tiered algorithmic approach in prehospital ECGs could lead to changes in CCL activation and decreased requirements for physician overread. This may have significant clinical and quality implications.

The Digital EMS California Academy of Learning: One State's Innovative Approach to EMS Fellow Education.

INTRODUCTION: Emergency medical services (EMS) fellowships are growing in significance within the United States prehospital health care system. While fellowships represent a cornerstone of EMS subspecialty education, an individual learner's experiences are limited by local resources and practices. California EMS fellowships have developed an innovative method for expanding fellows' educational experiences outside their immediate programs. THE INNOVATIVE EDUCATION METHOD: Each month, fellows, fellowship directors, and local EMS medical directors from throughout the state participate in a video conference. This meeting is divided into four distinct components: book chapter presentation, board-style question review, call review, and an EMS literature review. CHAPTER REVIEW: The two-volume text Emergency Medical Services: Clinical Practice and Systems Oversight has been categorized into 12 modules, one for each month of the fellowship. Every meeting, one fellow prepares a didactic presentation summarizing the highlights from that month's chapters. QUESTION REVIEW: Fellows each create five multiple-choice questions and answers, based on the section reading. Questions are assessed by the group, both for informational content and for appropriate formatting. After completion, these questions are submitted for future review for the EMS fellowship in-service examination. CALL REVIEW: Based on that month's module topics, a call is chosen and reviewed. Regional protocol and practice differences from different systems are discussed. The online medical oversight provided and the prehospital provider performance are evaluated by the group. LITERATURE REVIEW: Fellows not assigned to present a call or didactic segment each choose one paper focusing on a subject relevant to the module or call. Strengths of the study design, analysis, outcomes, and relevance to EMS practice are discussed. OUTCOMES: Fellows and experienced EMS attendings are exposed to different protocol and system approaches in an interactive and accessible format. This partnership expands educational opportunities for fellows and promotes collaboration across EMS systems.

An Urban 9-1-1 System's Experience with Left Ventricular Assist Device Patients.

Background: Left ventricular assist devices (LVADs) are used with increasing frequency and left in place for longer periods of time. Prior publications have focused on the mechanics of troubleshooting the device itself. We aim to describe the epidemiology of LVAD patient presentations to emergency medical services (EMS), prehospital assessments and interventions, and hospital outcomes. Methods: This is a retrospective chart review of known LVAD patients that belong to a single academic center's heart failure program who activated the 9-1-1 system and were transported by an urban EMS system to one of the center's 2 emergency departments between January 2012 and December 2015. Identifying demographics were used to query the electronic medical record of the responding city fire agency and contracted transporting ambulance service. Two reviewers abstracted prehospital chief complaint, vital signs, assessments, and interventions. Emergency department and hospital outcomes were retrieved separately. Results: From January 2012 to December 2015, 15 LVAD patients were transported 16 times. The most common prehospital chief complaint was weakness (7/16), followed by chest pain (3/16). Of the 7 patients presenting with weakness, one was diagnosed with a stroke in the emergency department. Another patient was diagnosed with subarachnoid hemorrhage and expired during hospital admission. This was the only death in the cohort. The most common hospital diagnosis was GI bleed (3/16). The overall admission rate was 87.5% (14/16). Conclusions: EMS interactions with LVAD patients are infrequent but have high rates of admission and incidence of life-threatening diagnoses. The most common prehospital presenting symptoms were weakness and chest pain, and most prehospital interactions did not require LVAD-specific interventions. In addition to acquiring technical knowledge regarding LVADs, EMS providers should be aware of non-device-related complications including intracranial and GI bleeding and take this into account during their assessment.

Establishing the Key Outcomes for Pediatric Emergency Medical Services Research.

The evidence supporting best practices when treating children in the prehospital setting or even the effect emergency medical services (EMS) has on patient outcomes is limited. Standardizing the critical outcomes for EMS research will allow for focused and comparable effort among the small but growing group of pediatric EMS investigators on specific topics. Standardized outcomes will also provide the opportunity to collectively advance the science of EMS for children and demonstrate the effect of EMS on patient outcomes. This article describes a consensus process among stakeholders in the pediatric emergency medicine and EMS community that identified the critical outcomes for EMS care in five clinical areas (traumatic brain injury, general injury, respiratory disease/failure, sepsis, and seizures). These areas were selected based on both their known public health importance and their commonality in EMS encounters. Key research outcomes identified by participating stakeholders using a modified nominal group technique for consensus building, which included small group brainstorming and independent voting for ranking outcomes that were feasible and/or important for the field.

Use of a Novel, Portable, LED-Based Capillary Refill Time Simulator within a Disaster Triage Context.

Introduction A simple, portable capillary refill time (CRT) simulator is not commercially available. This device would be useful in mass-casualty simulations with multiple volunteers or mannequins depicting a variety of clinical findings and CRTs. The objective of this study was to develop and evaluate a prototype CRT simulator in a disaster simulation context. METHODS: A CRT prototype simulator was developed by embedding a pressure-sensitive piezo crystal, and a single red light-emitting diode (LED) light was embedded, within a flesh-toned resin. The LED light was programmed to turn white proportionate to the pressure applied, and gradually to return to red on release. The time to color return was adjustable with an external dial. The prototype was tested for feasibility among two cohorts: emergency medicine physicians in a tabletop exercise and second year medical students within an actual disaster triage drill. The realism of the simulator was compared to video-based CRT, and participants used a Visual Analog Scale (VAS) ranging from "completely artificial" to "as if on a real patient." The VAS evaluated both the visual realism and the functional (eg, tactile) realism. Accuracy of CRT was evaluated only by the physician cohort. Data were analyzed using parametric and non-parametric statistics, and mean Cohen's Kappas were used to describe inter-rater reliability. RESULTS: The CRT simulator was generally well received by the participants. The simulator was perceived to have slightly higher functional realism (P=.06, P=.01) but lower visual realism (P=.002, P=.11) than the video-based CRT. Emergency medicine physicians had higher accuracy on portrayed CRT on the simulator than the videos (92.6% versus 71.1%; P<.001). Inter-rater reliability was higher for the simulator (0.78 versus 0.27; P<.001). CONCLUSIONS: A simple, LED-based CRT simulator was well received in both settings. Prior to widespread use for disaster triage training, validation on participants' ability to accurately triage disaster victims using CRT simulators and video-based CRT simulations should be performed. Chang TP , Santillanes G , Claudius I , Pham PK , Koved J , Cheyne J , Gausche-Hill M , Kaji AH , Srinivasan S , Donofrio JJ , Bir C . Use of a novel, portable, LED-based capillary refill time simulator within a disaster triage context. Prehosp Disaster Med. 2017;32(4):451-456.

Development of a Pediatric Mass Casualty Triage Algorithm Validation Tool.

BACKGROUND: Rapid, accurate evaluation and sorting of victims in a mass casualty incident (MCI) is crucial, as over-triage of victims may overwhelm a trauma system and under-triage may lead to an increase in morbidity and mortality. At this time, there is no validation tool specifically developed for the pediatric population to test an MCI algorithm's inherent capabilities to correctly triage children. OBJECTIVE: To develop a set of criteria for outcomes and interventions to be used as a validation tool for testing an MCI algorithm's ability to correctly triage patients from a cohort of pediatric trauma patients. METHODS: Expert opinion and literature review was used to formulate an initial Criteria Outcomes Tool (COT) that retrospectively categorizes pediatric (≤14 years of age) MCI victims based on resource utilization and clinical outcomes using the classic Red to Black MCI triage designations: Red - cardiopulmonary or mental status compromise needing intervention, Yellow - stable cardiopulmonary status but may require life or limb therapy, Green - minimally injured, and Black - deceased or likely to die given the circumstances. Using an anatomic approach, a list of criteria were defined and a modified-Delphi approach was used to create a summative COT that was reviewed by the American Academy of Pediatrics Disaster Preparedness Advisory Council. The resulting COT was independently applied to a weighted retrospective cohort of 25 pediatric victims from a single Level I trauma center by two reviewers to determine reproducibility. RESULTS: We created a Criteria Outcomes Tool (COT) with 47 outcomes and interventions to validate an MCI algorithm's triage designation. When the COT was applied to a cohort of 25 weighted pediatric charts, we identified the following resource utilization and outcome based triage designations: six Red, six Yellow, six Green, and seven Black triage outcomes. The 100% agreement was obtained between the two reviewers in each of the four categories. CONCLUSIONS: We designed an outcomes and resource utilization tool, the COT, to evaluate the ability of an MCI algorithm to correctly triage pediatric patients. Our tool has good reproducibility on initial study. KEY WORDS: pediatric; disaster; validation tools; triage algorithms; emergency.

Accuracy, Efficiency, and Inappropriate Actions Using JumpSTART Triage in MCI Simulations.

INTRODUCTION: Using the pediatric version of the Simple Triage and Rapid Treatment (JumpSTART) algorithm for the triage of pediatric patients in a mass-casualty incident (MCI) requires assessing the results of each step and determining whether to move to the next appropriate action. Inappropriate application can lead to performance of unnecessary actions or failure to perform necessary actions. Hypothesis/Problem To report overall accuracy and time required for triage, and to assess if the performance of unnecessary steps, or failure to perform required steps, in the triage algorithm was associated with inaccuracy of triage designation or increased time to reach a triage decision. METHODS: Medical students participated in an MCI drill in which they triaged both live actors portraying patients and computer-based simulated patients to the four triage levels: minor, delayed, immediate, and expectant. Their performance was timed and compared to intended triage designations and a priori determined critical actions. RESULTS: Thirty-three students completed 363 scenarios. The overall accuracy was 85.7% and overall mean time to assign a triage designation was 70.4 seconds, with decreasing times as triage acuity level decreased. In over one-half of cases, the student omitted at least one action and/or performed at least one action that was not required. Each unnecessary action increased time to triage by a mean of 8.4 seconds and each omitted action increased time to triage by a mean of 5.5 seconds. Discussion Increasing triage level, performance of inappropriate actions, and omission of recommended actions were all associated with increasing time to perform triage.

Comparison of Computerized Patients versus Live Moulaged Actors for a Mass-casualty Drill.

INTRODUCTION: Multiple modalities for simulating mass-casualty scenarios exist; however, the ideal modality for education and drilling of mass-casualty incident (MCI) triage is not established. Hypothesis/Problem Medical student triage accuracy and time to triage for computer-based simulated victims and live moulaged actors using the pediatric version of the Simple Triage and Rapid Treatment (JumpSTART) mass-casualty triage tool were compared, anticipating that student performance and experience would be equivalent. METHODS: The victim scenarios were created from actual trauma records from pediatric high-mechanism trauma presenting to a participating Level 1 trauma center. The student-reported fidelity of the two modalities was also measured. Comparisons were done using nonparametric statistics and regression analysis using generalized estimating equations. RESULTS: Thirty-three students triaged four live patients and seven computerized patients representing a spectrum of minor, immediate, delayed, and expectant victims. Of the live simulated patients, 92.4% were given accurate triage designations versus 81.8% for the computerized scenarios (P=.005). The median time to triage of live actors was 57 seconds (IQR=45-66) versus 80 seconds (IQR=58-106) for the computerized patients (P<.0001). The moulaged actors were felt to offer a more realistic encounter by 88% of the participants, with a higher associated stress level. CONCLUSION: While potentially easier and more convenient to accomplish, computerized scenarios offered less fidelity than live moulaged actors for the purposes of MCI drilling. Medical students triaged live actors more accurately and more quickly than victims shown in a computerized simulation.

Most routine laboratory testing of pediatric psychiatric patients in the emergency department is not medically necessary.

We examined the patient characteristics and hospital charges associated with routine medical clearance laboratory screening tests in 1,082 children younger than age eighteen who were brought to the emergency department (ED) for involuntary mental health holds--that is, each patient was brought to the ED to be evaluated for being a danger to him- or herself or to others, for being gravely disabled (unable to meet his or her basic needs due to a mental disorder), or both--from July 2009 to December 2010. Testing was performed on 871 of the children; all patients also received a clinical examination. The median charge for blood and urine testing together was $1,235, and the most frequent ordering pattern was the full comprehensive panel of tests. Of the patients with a nonconcerning clinical examination, 94.3 percent also had clinically nonsignificant test results. When we extrapolated cost savings to the national level, omitting routine screening laboratory tests in the population of pediatric patients presenting to the ED on an involuntary psychiatric hold with nonconcerning clinical exams could represent up to $90 million in savings annually, without reducing the ability to screen for emergency medical conditions. Provider-initiated diagnostic testing instead of routine screening would lead to significantly lower charges to the ED and the patient.

Impact of boarding pediatric psychiatric patients on a medical ward.

BACKGROUND AND OBJECTIVES: Psychiatric disorders account for an increasing number of pediatric hospitalizations. Due to lack of psychiatric beds, patients on involuntary psychiatric holds may be admitted to medical units. Our objectives were to evaluate the rate of admission of psychiatric patients to a medical unit, psychiatric care provided, and estimated cost of care. METHODS: The study involved retrospective chart review of all patients on involuntary psychiatric holds presenting to 1 pediatric emergency department from July 2009 to December 2010. We determined the rate of admission to a medical unit, the rate of counseling or psychiatric medication administration, and the estimated cost of nonmedical admissions (boarding) of patients on the medical unit. RESULTS: A total of 555 (50.1%) of 1108 patients on involuntary psychiatric holds were admitted to the pediatric medical unit. The majority (523 [94.2%]) were admitted for boarding because no psychiatric bed was available. Thirty-two (6.1%) patients admitted for isolated psychiatric reasons had counseling documented, and 105 (20.1%) received psychiatric medications. Patients admitted to an affiliated psychiatric hospital were significantly more likely to receive counseling and medications. Psychiatric patients were boarded in medical beds for 1169 days at an estimated cost of $2 232 790 or $4269 per patient over the 18-month period. CONCLUSIONS: We found high admission rates of patients on involuntary psychiatric holds to a pediatric medical unit with little psychiatric treatment in 1 hospital. Further research in other centers is required to determine the extent of the issue. Future studies of longer term outcomes (including readmission rates and assessments of functioning) are needed.

Clinical utility of screening laboratory tests in pediatric psychiatric patients presenting to the emergency department for medical clearance.

STUDY OBJECTIVE: We assess whether screening laboratory tests obtained to medically clear pediatric psychiatric patients altered management or disposition. METHODS: This was a retrospective chart review of consecutive patients younger than 18 years and presenting to an academic pediatric emergency department for medical clearance of an acute psychiatric emergency potentially requiring an involuntary hold (danger to self, danger to others, grave disability) from July 2009 to December 2010. Patients were identified by discharge diagnosis codes. History and physical examination and screening laboratory tests were reviewed for changes in management or disposition. Further analysis compared length of stay according to type of laboratory test performed. To avoid missing patients presenting with or for evaluation of an involuntary hold for whom an organic cause was diagnosed, charts with psychiatric chief complaints were reviewed for the same period. RESULTS: One thousand eighty-two visits resulting in 13,725 individual laboratory tests were analyzed. Of 871 visits with laboratory tests performed, abnormal laboratory tests were associated with 7 disposition changes (0.8%) and 50 management changes (5.7%) not associated with a disposition change. Twenty-five patients with noncontributory history and physical examination results had management changes, all non-urgent. One patient with a noncontributory history and physical examination result had a disposition-changing laboratory result, a positive urine pregnancy test. Patients who had any screening test performed had a longer length of stay than patients without testing (117 minutes longer; 95% confidence interval 109.7 to 124.4 minutes). In charts reviewed according to chief complaint, no patient was found to have an organic cause of their symptoms according to only screening tests. CONCLUSION: Screening laboratory tests resulted in few management and disposition changes in patients with noncontributory history and physical examination results but were associated with increased length of stay.

Temperature effects on surface pressure-induced changes in rat skin perfusion: implications in pressure ulcer development.

The effect of varying local skin temperature on surface pressure-induced changes in skin perfusion and deformation was determined in hairless fuzzy rats (13.5+/-3 mo, 474+/-25 g). Skin surface pressure was applied by a computer-controlled plunger with corresponding skin deformation measured by a linear variable differential transformer while a laser Doppler flowmeter measured skin perfusion. In Protocol I, skin surface perfusion was measured without heating (control, T=28 degrees C), with heating (T=36 degrees C), for control (probe just touching skin, 3.7 mmHg), and at two different skin surface pressures, 18 mmHg and 73 mmHg. Heating caused perfusion to increase at control and 18 mmHg pressure, but not at 73 mmHg. In Protocol II, skin perfusion was measured with and without heating as in Protocol I, but this time skin surface pressure was increased from 3.7 to 62 mmHg in increments of 3.7 mmHg. For unheated skin, perfusion increased as skin surface pressure increased from 3.7 to 18 mmHg. Further increases in surface pressure caused a decrease in perfusion until zero perfusion was reached for pressures over 55 mmHg. Heating increased skin perfusion for surface pressures from 3.7 to 18 mmHg, but not for pressures greater than 18 mmHg. After the release of surface pressure, the reactive hyperemia peak of perfusion increased with heating. In Protocol III, where skin deformation (creep and relaxation) was measured during the application of 3.7 and 18 mmHg, heating caused the tissue to be stiffer, allowing less deformation. It was found that for surface pressures below 18 mmHg, increasing skin temperature significantly increased skin perfusion and tissue stiffness. The clinical significance of these findings may have relevance in evaluating temperature and pressure effects on skin blood flow and deformation as well as the efficacy of using temperature as a therapeutic modality in the treatment of pressure ulcers.

Skin perfusion responses to surface pressure-induced ischemia: implication for the developing pressure ulcer.

This study describes alterations in skin perfusion in response to step increases in surface pressure, before and after long-term (5 hr) exposure to pressure-induced ischemia. A provocative test was developed in which surface pressure was increased in increments of 3.7 mmHg until perfusion reached an apparent minimum by a computer-controlled plunger that included a force cell, a laser Doppler flowmeter to determine perfusion, and a thermistor to monitor skin temperature. Force was applied to the greater trochanters of adult male fuzzy rats. Skin perfusion (n=7) initially increased with low levels of surface pressure (up to 13.9+/-1.9 mmHg) and then decreased with further increases in pressure, reaching minimum (zero) perfusion at 58.2+/-3.64 mmHg. After pressure release, reactive hyperemia (3 x normal) was observed, with levels returning to normal within 15-30 min. The provocative test was then applied after a 5-hr ischemic episode (produced by 92 mmHg) and 3 hr of recovery. A comparison of responses between stressed and unstressed skin revealed: elevated (63%) control perfusion levels; loss of the initial increase in perfusion with low levels of increasing pressure; a depression (45%) in the hyperemic response with delayed recovery time; and a decrease (54%) in amplitude of low frequency (<1 Hz) rhythms in skin perfusion. Skin surface temperature gradually increased both during the control period and the period of incremental increases in surface pressure (total DT=3.3 degrees C). The results suggest a compromised vasodilator mechanism(s). The provocative test developed in this study may have clinical potential for assessing tissue viability in early pressure ulcer development.

Improving chest pain evaluation within a multihospital network by the use of emergency department observation units.

BACKGROUND: Since 1993 the 13 VHA Southern New England (VHA-SNE) hospitals have been engaged in a regionally sponsored initiative to analyze and improve selected clinical processes. Nine of these hospitals have chosen to participate in an initiative in which observation units were postulated to offer a tool for improving the care of patients with chest pain-the VHA initiative to Implement Chest Pain Treatment in Observation Units. THE FIVE PHASES: In phase 1 of the initiative, the VHA-SNE's Clinical Benchmarking Work Group reviewed the medical literature, which confirmed longstanding systemic and pervasive problems in the evaluation of chest pain patients. The work group's preferred practice was the outpatient "rule out myocardial infarction [MI] evaluation" program during monitored observation; serial testing can accurately diagnose low- and moderate-probability patients with MI. In Phase 2 the study group surveyed the emergency departments in the nine hospitals, discovering significant variation in admission rates and practice patterns. During phase 3 the work group identified a health care organization demonstrating best-practice performance--one of the few hospitals in the nation with an operational outpatient "rule out MI evaluation" program. A team site-visited that organization and recorded information about its structure and processes. VHA-SNE then published a monograph that identified its current performance, described the best-practice approach, offered strategies to implement the model program, and analyzed the financial implications and return on investment. In phase 4 a pilot hospital implemented the model program, which in phase 5 is being extended to the other hospitals represented in the work group. Information regarding protocols, lessons learned, and barriers to implementation was freely provided.

Evaluation of ibuprofen for pressure ulcer prevention: application of a rat pressure ulcer model.

This blinded study describes the effect of ibuprofen (IBU) on experimental pressure ulcers (PU) induced in the fuzzy rat model. Ibuprofen's fibrinolytic activity has been found effective in preserving dermal vasculature in rats following burn injury. Experimental pressure ulcers were generated on the hips of fuzzy rats with the aid of computer control, using five daily, 6-hour pressure sessions. In the first study, 17 rats received intraperitoneal (I.P.) injection of IBU or saline control after each pressure session. In the second study, 44 rats received IBU or control, before, during, and after application of pressure by I.P. or intramuscular (I.M.) injections. Quantitation of histology is based on five prominent lesions, including: ulceration, infarction, panniculus carnosus necrosis, fat atrophy, and deep muscle necrosis. The following hypothesis was tested: Reperfusion injury and vascular occlusion in pressure ulcers may be similar to that which occurs in burns and, therefore, is responsive to IBU intervention. The results indicate that IBU does not have significant effects on the development of pressure ulcers. The mechanisms of IBU action in other organ and tissue systems are discussed in relation to the effect of IBU on the pressure ulcer model.

An animal model and computer-controlled surface pressure delivery system for the production of pressure ulcers.

Pressure ulcers continue to be a major health care problem. This paper describes an animal model and surface pressure delivery system for the production of experimentally derived pressure ulcers. A method for inducing dermal pressure lesions on the fuzzy rat was developed using a computer-controlled displacement column which produced a constant tissue interface pressure. The pressure column consists of a force transducer located between two 0.5-in (1.27-cm) diameter metal cylinders. The desired cutaneous pressure is maintained by a computer-controlled miniature stepper motor which displaces the column with the aid of interactive software. The force transducer signal is converted from analog to digital form, amplified, and recorded. Blood perfusion is monitored using a laser Doppler flowmeter (located in the tip of the column) during the application of pressure. The application of 145 mmHg pressure for 5 consecutive 6-hr sessions resulted in a greater than 90% incidence of pressure ulcers. The implications of our model and contributions of earlier animal models are discussed. This model provides a tightly controlled and measured environment making possible the scientific study of ulcer development and the evaluation of potential preventative or curative compounds.

Histopathology of pressure ulcers as a result of sequential computer-controlled pressure sessions in a fuzzy rat model.

This study describes the sequential histopathological changes that occur in the development of pressure ulcers experimentally induced in the fuzzy rat model. Computer-controlled pressure was applied for six hours at a maximum of five sessions, to skin over the greater trochanter of anesthetized rats. Lesions were similar, but more pronounced after the third, fourth, and fifth sessions as compared to the first or second sessions. Lesions developed first in the muscle rather than the dermis or epidermis. The lesion most often associated with pressure was necrosis of the panniculus carnosus muscle, often accompanied by damage to underlying adipose tissue. Recurrent pressure results in increasingly severe damage to the vascular system and parenchyma, consistent with an ischemia/reperfusion insult initiated through a free radical mechanism.