Case records of the Massachusetts General Hospital. Case 16-2006. A 72-year-old woman admitted to the emergency department because of a sudden change in mental status

Longitudinal Assessment of a Single Referring-Receiving Hospital Pair to Assess Air Versus Ground Elapsed Time From Transport Request to Arrival at Cardiac Catheterization Laboratory: An Observational Cohort Study

OBJECTIVE

Timely reperfusion is crucial for improving outcomes in patients with ST-elevation myocardial infarction (STEMI). The impact of transport mode on time to treatment for patients with STEMI over short distances (<10 miles) is not well studied. This study aimed to compare the time from transport request to percutaneous coronary intervention (PCI) suite arrival between helicopter emergency medical services (HEMS) and ground emergency medical services (GEMS) for patients with STEMI.

METHODS

We conducted a retrospective cohort study involving 22 patients with STEMI transported by either HEMS or GEMS from a single referring hospital to a single receiving hospital PCI suite, located 8 miles apart, from January 2020 to January 2023. Data on transport times were collected from hospital records and Google Maps estimates. We analyzed the time intervals using descriptive and inferential statistics, including mean comparisons and regression analyses.

RESULTS

Air transport (HEMS) was significantly faster than ground transport (GEMS) by a mean of 32 minutes (95% confidence interval: 21.1-42.9 minutes). This difference was clinically significant in 50% of the cases. Sensitivity analyses using longer HEMS transport times confirmed the robustness of the findings. No significant changes in transport times were observed over the study period.

CONCLUSION

HEMS may offer time advantages compared with GEMS for short-distance transfers in STEMI cases, though the small sample size limits the robustness of these findings. Further research with larger samples and additional outcome measures is needed to confirm these results and assess the broader implications for emergency medical transport.

Use of evidence in acute stroke decision-making: Implications for evidence-based medicine

RATIONALE, AIMS AND OBJECTIVES

Evidence-Based Medicine proposes a prescriptive model of physician decision-making in which 'best evidence' is used to guide best practice. And yet, proponents of EBM acknowledge that EBM fails to offer a systematic theory of physician decision-making.

METHODS

In this paper, we explore how physicians from the neurology and emergency medicine communities have responded to an evolving body of evidence surrounding the acute treatment of patients with ischemic stroke. Through analysis of this case study, we argue that EBM's vision of evidence-based medical decision-making fails to appreciate a process that we have termed epistemic evaluation.

RESULTS AND CONCLUSIONS

Physicians are required to interpret and apply any knowledge-even what EBM would term 'best evidence'-in light of their own knowledge, background and experience. This is consequential for EBM as understanding what physicians do and why they do it would appear to be essential to achieving optimal practice in accordance with best evidence.

Innate-like Lymphocytes and Innate Lymphoid Cells in Asthma

Asthma is a chronic pulmonary disease, highly associated with immune disorders. The typical symptoms of asthma include airway hyperresponsiveness (AHR), airway remodeling, mucus overproduction, and airflow limitation. The etiology of asthma is multifactorial and affected by genetic and environmental factors. Increasing trends toward dysbiosis, smoking, stress, air pollution, and a western lifestyle may account for the increasing incidence of asthma. Based on the presence or absence of eosinophilic inflammation, asthma is mainly divided into T helper 2 (Th2) and non-Th2 asthma. Th2 asthma is mediated by allergen-specific Th2 cells, and eosinophils activated by Th2 cells via the secretion of interleukin (IL)-4, IL-5, and IL-13. Different from Th2 asthma, non-Th2 asthma shows little eosinophilic inflammation, resists to corticosteroid treatment, and occurs mainly in severe asthmatic patients. Previous studies of asthma primarily focused on the function of Th2 cells, but, with the discovery of non-Th2 asthma and the involvement of innate lymphoid cells (ILCs) in the pathogenesis of asthma, tissue-resident innate immune cells in the lung have become the focus of attention in asthma research. Currently, innate-like lymphocytes (ILLs) and ILCs as important components of the innate immune system in mucosal tissues are reportedly involved in the pathogenesis of or protection against both Th2 and non-Th2 asthma. These findings of the functions of different subsets of ILLs and ILCs may provide clues for the treatment of asthma.

Automated segmentation and quantification of airway mucus with endobronchial optical coherence tomography

We propose a novel suite of algorithms for automatically segmenting the airway lumen and mucus in endobronchial optical coherence tomography (OCT) data sets, as well as a novel approach for quantifying the contents of the mucus. Mucus and lumen were segmented using a robust, multi-stage algorithm that requires only minimal input regarding sheath geometry. The algorithm performance was highly accurate in a wide range of airway and noise conditions. Mucus was classified using mean backscattering intensity and grey level co-occurrence matrix (GLCM) statistics. We evaluated our techniques in vivo in asthmatic and non-asthmatic volunteers.

Helicopter EMS and rapid transport for ST-elevation myocardial infarction: The HEARTS study

Background: Helicopter emergency medical services (HEMS) and ground EMS (GEMS) are both integral parts of out-of-hospital transport systems for patients with ST-elevation myocardial infarction (STEMI) undergoing emergency transport for primary percutaneous coronary intervention (PPCI). There are firm data linking time savings for PPCI transports with improved outcome. A previous pilot analysis generated preliminary estimates for potential HEMS-associated time savings for PPCI transports. Methods: This non-interventional multicenter study conducted over the period 2012–2014 at six centers in the USA and in the State of Qatar assessed a consecutive series of HEMS transports for PPCI; at one center consecutive GEMS transports of at least 15 miles were also assessed if they came from sites that also used HEMS (dual-mode referring hospitals). The study assessed time from ground or air EMS dispatch to transport a patient to a cardiac center, through to the time of patient arrival at the receiving cardiac unit, to determine proportions of patients arriving within accepted 90- and 120-minute time windows for PPCI. Actual times were compared to “route-mapping” GEMS times generated using geographical information software. HEMS' potential time savings were calculated using program-specific aircraft characteristics, and the potential time savings for HEMS was translated into estimated mortality benefit. Results: The study included 257 HEMS and 27 GEMS cases. HEMS cases had a high rate of overall transport time (from dispatch to receiving cardiac unit arrival) that fell within the predefined windows of 90 minutes (67.7% of HEMS cases) and 120 minutes (91.1% of HEMS cases). As compared to the calculated GEMS times, HEMS was estimated to accrue a median time saving of 32 minutes (interquartile range, 17–46). The number needed to transport for HEMS to get one additional case to PPCI within 90 minutes was 3. In the varied contexts of this multicenter study, the number of lives saved by HEMS, solely through time savings, was calculated as 1.34 per 100 HEMS PPCI transports. Conclusions: In this multicenter study, HEMS PPCI transport was found to be appropriate as defined by meeting predefined time windows. The overall estimate for lives saved through time savings alone was consistent with previous pilot data and was also generally consistent with favorable cost-effectiveness. Further research is necessary to confirm these findings, but judicious HEMS deployment for PPCI transports is justified by these data.

Role of type 1 natural killer T cells in pulmonary immunity

Mucosal sites are populated by a multitude of innate lymphoid cells and "innate-like" T lymphocytes expressing semiconserved T-cell receptors. Among the latter group, interest in type I natural killer T (NKT) cells has gained considerable momentum over the last decade. Exposure to NKT cell antigens is likely to occur continuously at mucosal sites. For this reason, and as they rapidly respond to stress-induced environmental cytokines, NKT cells are important contributors to immune and inflammatory responses. Here, we review the dual role of mucosal NKT cells during immune responses and pathologies with a particular focus on the lungs. Their role during pulmonary acute and chronic inflammation and respiratory infections is outlined. Whether NKT cells might provide a future attractive therapeutic target for treating human respiratory diseases is discussed.

Helicopter EMS: Research Endpoints and Potential Benefits

Patients, EMS systems, and healthcare regions benefit from Helicopter EMS (HEMS) utilization. This article discusses these benefits in terms of specific endpoints utilized in research projects. The endpoint of interest, be it primary, secondary, or surrogate, is important to understand in the deployment of HEMS resources or in planning further HEMS outcomes research. The most important outcomes are those which show potential benefits to the patients, such as functional survival, pain relief, and earlier ALS care. Case reports are also important "outcomes" publications. The benefits of HEMS in the rural setting is the ability to provide timely access to Level I or Level II trauma centers and in nontrauma, interfacility transport of cardiac, stroke, and even sepsis patients. Many HEMS crews have pharmacologic and procedural capabilities that bring a different level of care to a trauma scene or small referring hospital, especially in the rural setting. Regional healthcare and EMS system's benefit from HEMS by their capability to extend the advanced level of care throughout a region, provide a "backup" for areas with limited ALS coverage, minimize transport times, make available direct transport to specialized centers, and offer flexibility of transport in overloaded hospital systems.

Presumed guilty: natural killer T cell defects and human disease

Natural killer T (NKT) cells are important regulatory lymphocytes that have been shown in mouse studies, to have a crucial role in promoting immunity to tumours, bacteria and viruses, and in suppressing cell-mediated autoimmunity. Many clinical studies have indicated that NKT cell deficiencies and functional defects might also contribute to similar human diseases, although there is no real consensus about the nature of the NKT cell defects or whether NKT cells could be important for the diagnosis and/or treatment of these conditions. In this Review, we describe the approaches that have been used to analyse the NKT cell populations of various patient groups, suggest new strategies to determine how (or indeed, if) NKT cell defects contribute to human disease, and discuss the prospects for using NKT cells for therapeutic benefit.

Natural killer T cells and the regulation of asthma

A crucial role has been suggested for invariant natural killer T cells (iNKT) in regulating the development of asthma, a complex and heterogeneous disease characterized by airway inflammation and airway hyperreactivity (AHR). iNKT cells constitute a unique subset of T cells responding to endogenous and exogenous lipid antigens, rapidly secreting a large amount of cytokines, which amplify both innate and adaptive immunity. Herein, we review recent studies showing a requirement for iNKT cells in various models of asthma in mice and monkeys as well as studies in human patients. Surprisingly, in several different murine models of asthma, distinct subsets of iNKT cells were required, suggesting that iNKT cells serve as a common critical pathogenic element for many different forms of asthma. The importance of iNKT cells in both allergic and non-allergic forms of asthma, which are independent of adaptive immunity and associated with airway neutrophils, may explain situations previously found to be incompatible with the Th2 paradigm of asthma.

Air Transport of Patients with Unstable Aortic Aneurysms Directly into Operating Rooms

OBJECTIVE

The purpose of this study was to describe an air transport service's protocol for direct transport of patients with abdominal aortic aneurysm leak (AAAL) into receiving hospital operating rooms (ORs).

METHODS

This retrospective consecutive-case analysis examined AAAL patients undergoing nurse-paramedic Boston MedFlight (BMF) transport during 1999-2004, who were taken directly into ORs at four academic centers. BMF uses a rotating roster system to assign receiving hospitals when referring physicians have no preidentified receiving facility, but this practice may prolong patient transport or be associated with less diagnostic certainty, and thus more delay, at receiving hospitals. Thus, the study compared "Roster" versus "Non-roster" patients' time and outcome end points. Continuous nonparametric data (e.g., time intervals) were described with median and interquartile range (IQR). Chi-square and Kruskal-Wallis tests were used for univariate comparisons; regression analysis assessed dependent variables while adjusting for covariates (e.g., transport mileage).

RESULTS

There were 29 direct-to-OR transports, with median distance of 30 miles. All patients had AAAL diagnosis confirmed; 51.7% survived. System performance for end points was similar as assessed between Roster versus Non-roster patients.

CONCLUSIONS

Interfacility direct-to-OR transport of AAAL patients is feasible. Use of a roster system allows for timely transport facilitation for patients needing specialized care; roster patients achieve similar end points as did patients who had already-identified receiving hospitals upon air medical transport request.

Recent advances in the role of NKT cells in allergic diseases and asthma

Asthma is the result of chronic airway inflammation that is dominated by the presence of eosinophils and CD4(+) T lymphocytes. CD4(+) T cells include several subsets and play a critical role in orchestrating the inflammation, predominantly by secreting interleukin-4 and interleukin-13. Recently, research identified a new subset of T cells, natural killer T (NKT) cells, which also express the CD4 marker. In contrast to conventional CD4(+) T cells, NKT cells do not respond to peptide antigens, but rather to glycolipids. In animal models of asthma, direct activation of NKT cells by glycolipids results in the secretion of extensive amounts of cytokines and triggers the development of airway hyperreactivity. Moreover, in patients with chronic asthma, NKT cells can be found in bronchoalveolar lavage fluids in significant amounts. These data strongly suggest that NKT cells play an important role in asthma pathogenesis.

Jaundice in the newborns

Hyperbilirubinemia is the commonest morbidity in the neonatal period and 5-10% of all newborns require intervention for pathological jaundice. Neonates on exclusive breast-feeding have a different pattern and degree of jaundice as compared to artificially fed babies. Latest guidelines from the American Academy of Pediatrics (AAP) for management of jaundice in a normal term newborn have been included in the protocol. Separate guidelines have been provided for the management of jaundice in sick term babies, preterm and low birth weight babies, for hemolytic jaundice and prolonged hyperbilirubinemia.

Helicopter emergency medical services and stroke care regionalization: measuring performance in a maturing system

This study retrospectively analyzed 123 patients undergoing helicopter emergency medical services transport for ischemic stroke (ischemic cerebrovascular accident) to the Massachusetts General Hospital during 2000-2004. To assess for system improvements over time, data were analyzed between the 2 consecutive 30-month periods comprising the 5-year study. Patients transported during the latter 30 months were transported from lesser distances (P = .002), were more likely to be younger than 65 years (P = .005), and were more likely to have documented symptom onset time (P = .03) and National Institutes of Health Stroke Scale (odds ratio, 3.6; 95% confidence interval, 1.7-7.6; P = .001). Time end points analysis found no significant improvements in any intervals compared across the 2 study eras. Age older than 65 years was the only covariate associated with a more rapid arrival at the Massachusetts General Hospital (odds ratio, 2.4; 95% CI, 1.1-5.4; P = .03). This study of our stroke transport system identified both areas of good performance and also areas for focusing further improvement efforts.

Asthma: new developments concerning immune mechanisms, diagnosis and treatment

PURPOSE OF REVIEW

This brief review discusses how recent research may modify our understanding of the immunology of asthma. Consideration is given to the possible impact that these observations may have upon diagnostic and therapeutic strategies.

RECENT FINDINGS

New studies indicate that current conceptions regarding the balance between Th1 and Th2 systems may need modification. The relationship between infection and the development of asthma in children has proven to be much more complex than originally suggested by the 'hygiene hypothesis'. In addition, important genetic differences have been found in the response of asthmatic patients to therapeutic agents.

SUMMARY

Greater insight into the mechanisms responsible for asthma and the introduction of new drugs will depend in part upon the development of reliable and simple methods for detecting airway inflammation. As the immunologic aspects of asthma are dissected, we can expect that many more potential targets for treatment will be discovered, but treatment may have to be individualized for genetic differences between different individuals.