Echocardiography findings in COVID-19 patients admitted to intensive care units: a multi-national observational study (the ECHO-COVID study)

PURPOSE

Severely ill patients affected by coronavirus disease 2019 (COVID-19) develop circulatory failure. We aimed to report patterns of left and right ventricular dysfunction in the first echocardiography following admission to intensive care unit (ICU).

METHODS

Retrospective, descriptive study that collected echocardiographic and clinical information from severely ill COVID-19 patients admitted to 14 ICUs in 8 countries. Patients admitted to ICU who received at least one echocardiography between 1st February 2020 and 30th June 2021 were included. Clinical and echocardiographic data were uploaded using a secured web-based electronic database (REDCap).

RESULTS

Six hundred and seventy-seven patients were included and the first echo was performed 2 [1, 4] days after ICU admission. The median age was 65 [56, 73] years, and 71% were male. Left ventricle (LV) and/or right ventricle (RV) systolic dysfunction were found in 234 (34.5%) patients. 149 (22%) patients had LV systolic dysfunction (with or without RV dysfunction) without LV dilatation and no elevation in filling pressure. 152 (22.5%) had RV systolic dysfunction. In 517 patients with information on both paradoxical septal motion and quantitative RV size, 90 (17.4%) had acute cor pulmonale (ACP). ACP was associated with mechanical ventilation (OR > 4), pulmonary embolism (OR > 5) and increased PaCO₂. Exploratory analyses showed that patients with ACP and older age were more likely to die in hospital (including ICU).

CONCLUSION

Almost one-third of this cohort of critically ill COVID-19 patients exhibited abnormal LV and/or RV systolic function in their first echocardiography assessment. While LV systolic dysfunction appears similar to septic cardiomyopathy, RV systolic dysfunction was related to pressure overload due to positive pressure ventilation, hypercapnia and pulmonary embolism. ACP and age seemed to be associated with mortality in this cohort.

Criteria, Processes, and Determination of Competence in Basic Critical Care Echocardiography Training: A Delphi Process Consensus Statement by the Learning Ultrasound in Critical Care (LUCC) Initiative

BACKGROUND

With the paucity of high-quality studies on longitudinal basic critical care echocardiography (BCCE) training, expert opinion guidelines have guided BCCE competence educational standards and processes. However, existing guidelines lack precise detail due to methodological flaws during guideline development.

RESEARCH QUESTIONS

To formulate methodologically robust guidelines on BCCE training using evidence and expert opinion, detailing specific criteria for every step, we conducted a modified Delphi process using the principles of the validated AGREE-II tool. Based on systematic reviews, the following domains were chosen: components of a longitudinal BCCE curriculum; pass-grade criteria for image-acquisition and image-interpretation; and formative/summative assessment and final competence processes.

STUDY DESIGN AND METHODS

Between April 2020 and May 2021, a total of 21 BCCE experts participated in four rounds. Rounds 1 and 2 used five web-based questionnaires, including branching-logic software for directed questions to individual panelists. In round 3 (videoconference), the panel finalized the recommendations by vote. During the journal peer-review process, Round 4 was conducted as Web-based questionnaires. Following each round, the agreement threshold for each item was determined as ≥ 80% for item inclusion and ≤ 30% for item exclusion.

RESULTS

Following rounds 1 and 2, agreement was reached on 62 of 114 items. To the 49 unresolved items, 12 additional items were added in round 3, with 56 reaching agreement and five items remaining unresolved. There was agreement that longitudinal BCCE training must include introductory training, mentored formative training, summative assessment for competence, and final cognitive assessment. Items requiring multiple rounds included two-dimensional views, Doppler, cardiac output, M-mode measurement, minimum scan numbers, and pass-grade criteria. Regarding objective criteria for image-acquisition and image-interpretation quality, the panel agreed on maintaining the same criteria for formative and summative assessment, to categorize BCCE findings as major vs minor and a standardized approach to errors, criteria for readiness for summative assessment, and supervisory options.

INTERPRETATION

In conclusion, this expert consensus statement presents comprehensive evidence-based recommendations on longitudinal BCCE training. However, these recommendations require prospective validation.

Lung Ultrasound for Patients With Coronavirus Disease 2019 Pulmonary Disease

Given the general utility of lung ultrasound for the evaluation of respiratory failure in acutely ill patients, it is logical to consider its specific advantages in coronavirus disease 2019-related pulmonary disease. The authors, representing the extensive experience of the North American and European coronavirus disease 2019 epicenters, present an ultrasound scanning protocol and report on the common associated ultrasound findings.

The PRICES statement: an ESICM expert consensus on methodology for conducting and reporting critical care echocardiography research studies

PURPOSE

Echocardiography is a common tool for cardiac and hemodynamic assessments in critical care research. However, interpretation (and applications) of results and between-study comparisons are often difficult due to the lack of certain important details in the studies. PRICES (Preferred Reporting Items for Critical care Echocardiography Studies) is a project endorsed by the European Society of Intensive Care Medicine and conducted by the Echocardiography Working Group, aiming at producing recommendations for standardized reporting of critical care echocardiography (CCE) research studies.

METHODS

The PRICE panel identified lists of clinical and echocardiographic parameters (the "items") deemed important in four main areas of CCE research: left ventricular systolic and diastolic functions, right ventricular function and fluid management. Each item was graded using a critical index (CI) that combined the relative importance of each item and the fraction of studies that did not report it, also taking experts' opinion into account.

RESULTS

A list of items in each area that deemed essential for the proper interpretation and application of research results is recommended. Additional items which aid interpretation were also proposed.

CONCLUSION

The PRICES recommendations reported in this document, as a checklist, represent an international consensus of experts as to which parameters and information should be included in the design of echocardiography research studies. PRICES recommendations provide guidance to scientists in the field of CCE with the objective of providing a recommended framework for reporting of CCE methodology and results.

Lung Ultrasound Scanning for Respiratory Failure in Acutely Ill Patients: A Review

Lung ultrasonography (LUS), an imaging modality quickly performed, interpreted, and integrated by the treating physician at the bedside, is a particularly useful tool for acutely ill patients. In the evaluation of a patient with respiratory failure in the ICU or ED, LUS is superior to chest radiograph and generally comparable with CT imaging and reduces the need for patient transport and radiation exposure. This article will provide a concise review of LUS as it pertains to respiratory failure in general and will include examples of relevant ultrasound images and video clips from critically ill patients.

Recommendations for core critical care ultrasound competencies as a part of specialist training in multidisciplinary intensive care: a framework proposed by the European Society of Intensive Care Medicine (ESICM)

Abstract

Critical care ultrasound (CCUS) is an essential component of intensive care practice. Although existing international guidelines have focused on training principles and determining competency in CCUS, few countries have managed to operationalize this guidance into an accessible, well-structured programme for clinicians training in multidisciplinary intensive care. We seek to update and reaffirm appropriate CCUS scope so that it may be integrated into the international Competency-based Training in Intensive Care Medicine. The resulting recommendations offer the most contemporary and evolved set of core CCUS competencies for an intensive care clinician yet described. Importantly, we discuss the rationale for inclusion but also exclusion of competencies listed.

Background/aim

Critical care ultrasound (CCUS) is an essential component of intensive care practice. The purpose of this consensus document is to determine those CCUS competencies that should be a mandatory part of training in multidisciplinary intensive care.

Methods

A three-round Delphi method followed by face-to-face meeting among 32 CCUS experts nominated by the European Society of Intensive Care Medicine. Agreement of at least 90% of experts was needed in order to enlist a competency as mandatory.

Results

The final list of competencies includes 15 echocardiographic, 5 thoracic, 4 abdominal, deep vein thrombosis diagnosis and central venous access aid.

Conclusion

The resulting recommendations offer the most contemporary and evolved set of core CCUS competencies for an intensive care clinician yet described.

0649 Ultrasound Assessment of Tongue Movement as a Predictor of Response to Hypoglossal Nerve Stimulation (HGNS)

Introduction

HGNS is an approved therapy for obstructive sleep apnea (OSA). Initial setting of HGNS voltage is based on observation of anterior tongue movement, which may not reflect opening of the retroglossal airway. We developed an ultrasonographic (US) technique to assess tongue movement with HGNS. We correlated US measures of tongue movement at the initial HGNS voltage setting with the AHI determined by PSG/HSAT on HGNS therapy.

Methods

Eleven subjects implanted with INSPIRE™ (HGNS) were enrolled at least one month post-implantation. Initial HGNS voltage was determined while awake and semi-recumbent and set to achieve visualized anterior tongue protrusion at a tolerable stimulation voltage. A curvilinear probe (5-2MHz) was placed longitudinally in the submental region at the midline with the indicator pointed anteriorly. Hyoid bone excursion (HBE) with stimulation was used as a marker of base of tongue movement. PSG or HSAT was performed to determine AHI with HGNS. Responders were defined as those with a reduction in AHI ≥50% and an AHI <20 events/hr.

Results

N=11, 6M, 5F, Age=66.5 ±18.4 years, BMI=27.9±2.7 kg/m2. Pre-treatment AHI=38.8±13.4/hr, T-90%=10.5±16.7%. Mean HBE in responders=1.02±0.17cm vs 0.76±0.20cm in non-responders (p=0.006). Best subsets regression analysis performed using post-treatment AHI as the dependent variable and age, BMI, baseline AHI, HBE and HGNS voltage as independent variables showed that HBE (coef. -29.1, p=0.038) and BMI (coef. 2.6, p=0.018) were independent predictors of response.

Conclusion

We demonstrated that ultrasound assessment of HBE during HGNS may be a useful tool to predict response to therapy and guide HGNS settings. HBE, rather than voltage, predicted post-treatment AHI.

Support

None.

Systematic review and literature appraisal on methodology of conducting and reporting critical-care echocardiography studies: a report from the European Society of Intensive Care Medicine PRICES expert panel

Background

The echocardiography working group of the European Society of Intensive Care Medicine recognized the need to provide structured guidance for future CCE research methodology and reporting based on a systematic appraisal of the current literature. Here is reported this systematic appraisal.

Methods

We conducted a systematic review, registered on the Prospero database. A total of 43 items of common interest to all echocardiography studies were initially listed by the experts, and other “topic-specific” items were separated into five main categories of interest (left ventricular systolic function, LVSF n = 15, right ventricular function, RVF n = 18, left ventricular diastolic function, LVDF n = 15, fluid management, FM n = 7, and advanced echocardiography techniques, AET n = 17). We evaluated the percentage of items reported per study and the fraction of studies reporting a single item.

Results

From January 2000 till December 2017 a total of 209 articles were included after systematic search and screening, 97 for LVSF, 48 for RVF, 51 for LVDF, 36 for FM and 24 for AET. Shock and ARDS were relatively common among LVSF articles (both around 15%) while ARDS comprised 25% of RVF articles. Transthoracic echocardiography was the main echocardiography mode, in 87% of the articles for AET topic, followed by 81% for FM, 78% for LVDF, 70% for LVSF and 63% for RVF. The percentage of items per study as well as the fraction of study reporting an item was low or very low, except for FM. As an illustration, the left ventricular size was only reported by 56% of studies in the LVSF topic, and half studies assessing RVF reported data on pulmonary artery systolic pressure.

Conclusion

This analysis confirmed sub-optimal reporting of several items listed by an expert panel. The analysis will help the experts in the development of guidelines for CCE study design and reporting.

Validation of a Host Response Assay, SeptiCyte LAB, for Discriminating Sepsis from Systemic Inflammatory Response Syndrome in the ICU

RATIONALE

A molecular test to distinguish between sepsis and systemic inflammation of noninfectious etiology could potentially have clinical utility.

OBJECTIVES

This study evaluated the diagnostic performance of a molecular host response assay (SeptiCyte LAB) designed to distinguish between sepsis and noninfectious systemic inflammation in critically ill adults.

METHODS

The study employed a prospective, observational, noninterventional design and recruited a heterogeneous cohort of adult critical care patients from seven sites in the United States (n = 249). An additional group of 198 patients, recruited in the large MARS (Molecular Diagnosis and Risk Stratification of Sepsis) consortium trial in the Netherlands ( www.clinicaltrials.gov identifier NCT01905033), was also tested and analyzed, making a grand total of 447 patients in our study. The performance of SeptiCyte LAB was compared with retrospective physician diagnosis by a panel of three experts.

MEASUREMENTS AND MAIN RESULTS

In receiver operating characteristic curve analysis, SeptiCyte LAB had an estimated area under the curve of 0.82-0.89 for discriminating sepsis from noninfectious systemic inflammation. The relative likelihood of sepsis versus noninfectious systemic inflammation was found to increase with increasing test score (range, 0-10). In a forward logistic regression analysis, the diagnostic performance of the assay was improved only marginally when used in combination with other clinical and laboratory variables, including procalcitonin. The performance of the assay was not significantly affected by demographic variables, including age, sex, or race/ethnicity.

CONCLUSIONS

SeptiCyte LAB appears to be a promising diagnostic tool to complement physician assessment of infection likelihood in critically ill adult patients with systemic inflammation. Clinical trial registered with www.clinicaltrials.gov (NCT01905033 and NCT02127502).

Correction to: A decade of progress in critical care echocardiography: a narrative review

The original version of this article unfortunately contained a mistake.

Physician agreement on the diagnosis of sepsis in the intensive care unit: estimation of concordance and analysis of underlying factors in a multicenter cohort

Background

Differentiating sepsis from the systemic inflammatory response syndrome (SIRS) in critical care patients is challenging, especially before serious organ damage is evident, and with variable clinical presentations of patients and variable training and experience of attending physicians. Our objective was to describe and quantify physician agreement in diagnosing SIRS or sepsis in critical care patients as a function of available clinical information, infection site, and hospital setting.

Methods

We conducted a post hoc analysis of previously collected data from a prospective, observational trial (N = 249 subjects) in intensive care units at seven US hospitals, in which physicians at different stages of patient care were asked to make diagnostic calls of either SIRS, sepsis, or indeterminate, based on varying amounts of available clinical information (clinicaltrials.gov identifier: NCT02127502). The overall percent agreement and the free-marginal, inter-observer agreement statistic kappa (κ_free) were used to quantify agreement between evaluators (attending physicians, site investigators, external expert panelists). Logistic regression and machine learning techniques were used to search for significant variables that could explain heterogeneity within the indeterminate and SIRS patient subgroups.

Results

Free-marginal kappa decreased between the initial impression of the attending physician and (1) the initial impression of the site investigator (κ_free 0.68), (2) the consensus discharge diagnosis of the site investigators (κ_free 0.62), and (3) the consensus diagnosis of the external expert panel (κ_free 0.58). In contrast, agreement was greatest between the consensus discharge impression of site investigators and the consensus diagnosis of the external expert panel (κ_free 0.79). When stratified by infection site, κ_free for agreement between initial and later diagnoses had a mean value + 0.24 (range − 0.29 to + 0.39) for respiratory infections, compared to + 0.70 (range + 0.42 to + 0.88) for abdominal + urinary + other infections. Bioinformatics analysis failed to clearly resolve the indeterminate diagnoses and also failed to explain why 60% of SIRS patients were treated with antibiotics.

Conclusions

Considerable uncertainty surrounds the differential clinical diagnosis of sepsis vs. SIRS, especially before organ damage has become highly evident, and for patients presenting with respiratory clinical signs. Our findings underscore the need to provide physicians with accurate, timely diagnostic information in evaluating possible sepsis.

Electronic supplementary material

The online version of this article (10.1186/s40560-019-0368-2) contains supplementary material, which is available to authorized users.

A Regional, Cost-Effective, Collaborative Model for Critical Care Fellows' Ultrasonography Education

OBJECTIVE

Training in critical care ultrasonography is an essential tool in critical care medicine and recommended for fellowship programs in pulmonary and critical care medicine. Major barriers to implementing competency-based training in individual fellowship programs include a lack of expert faculty, time, and funding. Our objective was to investigate whether regional collaboration to deliver an introductory critical care ultrasonography course for fellows might overcome these barriers while achieving international training standards.

METHODS

This was a retrospective review of course evaluation and learner assessment data from a 3-day ultrasonography course between 2012 and 2017. All critical care fellows (n = 545) attending the course completed pre- and postcourse surveys and postcourse knowledge and technical skills tests. Evaluation of educational outcomes was performed based on the Kirkpatrick model.

RESULTS

Fellows reported minimal prior formal training in ultrasonography, and ultrasound-guided vascular access was the most common area of prior training. The course was a blended model of didactic lectures coordinated with real-time demonstration scanning using live models, hands-on training on human models and task trainers, and interpretation of ultrasonography images with a wide range of pathology. Course content included basic echocardiography and general critical care ultrasonography (lung, pleural, vascular diagnostic, vascular access, and abdominal ultrasonography). At the conclusion of the course, fellows demonstrated high levels of knowledge and skill competence on a previously validated assessment tool and significantly improved confidence in all content areas. Barriers to training at individual programs were overcome through faculty cooperation, faculty development, and cost sharing. Success of this model is supported by the sustained growth of this course.

CONCLUSIONS

A regional collaborative model for training fellows in ultrasonography is a feasible, efficient, and flexible model for delivering curricula, where expertise at individual programs is not routinely available.

Serial Diaphragm Ultrasonography to Predict Successful Discontinuation of Mechanical Ventilation

INTRODUCTION

Diaphragm excursion and contraction velocity measured using ultrasonography have been used to assess diaphragm function. We aimed to evaluate the performance of diaphragm ultrasonography during weaning from mechanical ventilation (MV).

METHODS

Diaphragm ultrasonography was performed on 73 mechanically ventilated patients who were being considered for extubation on three separate occasions: (1) on assist control mode (A/C) during consistent patient triggered ventilation, (2) following 30 min during a spontaneous breathing trial (SBT), (3) 4-24 h following extubation. Right hemidiaphragm excursion and contraction velocity were measured on A/C, during SBT, and following extubation. These measurements were correlated with the outcome of extubation.

RESULTS

Twenty patients failed extubation: 6 of whom required re-intubation and 14 of whom required non-invasive ventilatory support. During SBT, the mean diaphragm excursions were 1.7 ± 0.82 cm in the group who failed extubation compared to 2.1 ± 0.9 cm in the group who were successfully extubated (p = 0.06). To predict successful extubation, a decrease in diaphragm excursion of < 16.4% between A/C and SBT had a sensitivity of 84.9% and a specificity of 65%. The area under curve (AUC) for receiver operative characteristics for above cut-off was 0.75. Diaphragm contraction velocity performed poorly in predicting weaning outcome.

CONCLUSIONS

Diaphragm excursion measured during SBT is an imperfect predictor of the outcome of extubation. Maintenance of diaphragm excursion between A/C and SBT has good performance characteristics by AUC analysis. Diaphragm contraction velocity has poor ability to predict outcome of extubation.

Diaphragm Excursion-Time Index: A New Parameter Using Ultrasonography to Predict Extubation Outcome

BACKGROUND

The diaphragmatic response to increased mechanical load following withdrawal of mechanical ventilation is critical in determining the outcome of extubation. Using ultrasonography, we aimed to evaluate the performance of the excursion-time (E-T) index-a product of diaphragm excursion and inspiratory time, to predict the outcome of extubation.

METHODS

Right hemidiaphragm excursion, inspiratory time, and E-T index were measured by ultrasonography during mechanical ventilation: (1) on assist-control (A/C) mode during consistent patient-triggered ventilation, (2) following 30 min during a spontaneous breathing trial (SBT), and (3) between 4 and 24 h following extubation. These measurements were correlated with the outcome of extubation. Patients in the "failure" group required reintubation or noninvasive ventilation within 48 h of extubation.

RESULTS

Of the 73 patients studied, 20 patients failed extubation. During SBT, diaphragm excursion was 1.65 ± 0.82 and 2.1 ± 0.9 cm (P = .06), inspiratory time was 0.89 ± 0.30 and 1.11 ± 0.39 s (P = .03), and the E-T index was 1.64 ± 1.19 and 2.42 ± 1.55 cm-s (P < .03) in the "failure" and "success" groups, respectively. The mean change in E-T index between A/C and SBT was -3.9 ± 57.8% in the failure group and 59.4 ± 74.6% in the success group (P < .01). A decrease in diaphragmatic E-T index less than 3.8% between A/C and SBT had a sensitivity of 79.2% and a specificity of 75%, to predict successful extubation.

CONCLUSIONS

Diaphragm E-T index measured during SBT may help predict the outcome of extubation. Maintenance or increase in diaphragm E-T index between A/C and SBT increases the likelihood of successful extubation.

Lung ultrasonography in end-stage renal disease: moving from evidence to practice-a narrative review

Traditionally, point of care ultrasonography in nephrology has been used for renal biopsies and dialysis line placement. However, there is an emerging literature supporting the value of point of care lung ultrasonography in the assessment of volume status for dialysis patients. We conducted a review and identified 12 studies that examined the utility of lung ultrasonography in assessing volume status in patients with end-stage renal disease. We conclude that lung ultrasonography can be used to determine volume status in chronic dialysis patients by identifying lung congestion using the B-line score. Incorporating this technique into practice may have significant diagnostic and prognostic value for this high-risk population, as it provides the nephrologist with a useful bedside technique to assess extravascular lung water. Developing competence in lung ultrasonography is straightforward. The nephrology community should consider adding this useful tool into fellowship training, paralleling its broader use in other internal medicine specialties.

The Rapid Assessment of Competency in Echocardiography Scale: Validation of a Tool for Point-of-Care Ultrasound

OBJECTIVES

Increased use of point-of-care ultrasound (US) requires the development of assessment tools that measure the competency of learners. In this study, we developed and tested a tool to assess the quality of point-of-care cardiac US studies performed by novices.

METHODS

In phase 1, the Rapid Assessment of Competency in Echocardiography (RACE) scale was developed on the basis of structured interviews with subject matter experts; the tool was then piloted on a small series of US studies in phase 2. In phase 3, the tool was applied to a sample of 154 point-of-care US studies performed by 12 learners; each study was independently rated by 2 experts, with quantitative analysis subsequently performed.

RESULTS

Evidence of the content validity of the RACE scale was supported by a consensus exercise, wherein experts agreed on the assessment dimensions and specific items that made up the RACE scale. The tool showed good inter-rater reliability. An analysis of inter-item correlations provided support for the internal structure of the scale, and the tool was able to discriminate between learners early in their point-of-care US learning and those who were more advanced in their training.

CONCLUSIONS

The RACE scale provides a straightforward means to assess learner performance with minimal requirements for evaluator training. Our results support the conclusion that the tool is an effective means of making valid judgments regarding competency in point-of-care cardiac US.

Development and Validation of an Assessment Tool for Competency in Critical Care Ultrasound

BACKGROUND

Point-of-care ultrasound is an emerging technology in critical care medicine. Despite requirements for critical care medicine fellowship programs to demonstrate knowledge and competency in point-of-care ultrasound, tools to guide competency-based training are lacking.

OBJECTIVE

We describe the development and validity arguments of a competency assessment tool for critical care ultrasound.

METHODS

A modified Delphi method was used to develop behaviorally anchored checklists for 2 ultrasound applications: "Perform deep venous thrombosis study (DVT)" and "Qualify left ventricular function using parasternal long axis and parasternal short axis views (Echo)." One live rater and 1 video rater evaluated performance of 28 fellows. A second video rater evaluated a subset of 10 fellows. Validity evidence for content, response process, and internal consistency was assessed.

RESULTS

An expert panel finalized checklists after 2 rounds of a modified Delphi method. The DVT checklist consisted of 13 items, including 1.00 global rating step (GRS). The Echo checklist consisted of 14 items, and included 1.00 GRS for each of 2 views. Interrater reliability evaluated with a Cohen kappa between the live and video rater was 1.00 for the DVT GRS, 0.44 for the PSLA GRS, and 0.58 for the PSSA GRS. Cronbach α was 0.85 for DVT and 0.92 for Echo.

CONCLUSIONS

The findings offer preliminary evidence for the validity of competency assessment tools for 2 applications of critical care ultrasound and data on live versus video raters.

A Biologically Active Analog of the Sex Pheromone of the Emerald Ash Borer, Agrilus planipennis

The emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae) (EAB), is an invasive species causing unprecedented levels of mortality to ash trees in its introduced range. The female-produced sex pheromone of EAB has been shown to contain the macrocyclic lactone (3Z)-dodecen-12-olide. This compound and its geometrical isomer, (3E)-dodecen-12-olide, have been demonstrated previously to be EAG active and, in combination with a host-derived green leaf volatile, (3Z)-hexenol, to be attractive to male EAB in green prism traps deployed in the ash tree canopy. In the current study, we show that the saturated analog, dodecan-12-olide, is similarly active, eliciting an antennal response and significant attraction of EAB in both olfactometer and trapping bioassays in green traps with (3Z)-hexenol. Conformational modeling of the three lactones reveals that their energies and shapes are very similar, suggesting they might share a common receptor in EAB antennae. These findings provide new insight into the pheromone ecology of this species, highlighting the apparent plasticity in response of adults to the pheromone and its analog. Both of the unsaturated isomers are costly to synthesize, involving multistep, low-yielding processes. The saturated analog can be made cheaply, in high yield, and on large scale via Mitsunobu esterification of a saturated ω-hydroxy acid or more simply by Baeyer-Villiger oxidation of commercially available cyclododecanone. The analog can thus provide an inexpensive option as a lure for detection surveys as well as for possible mitigation purposes, such as mating disruption.

Identification of sex pheromone components of blueberry spanworm Itame argillacearia (Lepidoptera: Geometridae)

Blueberry spanworm, Itame argillacearia (Packard), is an important defoliator of lowbush (syn. 'wild') blueberry, Vaccinium angustifolium Aiton, in north-eastern North America. The goal of the present study was to identify the female I. argillacearia sex pheromone, which could be used in traps for monitoring or mass-trapping this pest. Gas chromatography/mass spectrometry (GC/MS) and electroantennogram (EAG) recordings of sex pheromone gland extracts, in combination with chemical synthesis, a Y-tube olfactometer study and field experiments confirmed (2R,3S)-2-ethyl-3-((Z,Z)-tridecadi-2,5-enyl) oxirane (hereafter (Z,Z)-(3R,4S)-3,4-epoxy-6,9-heptadecadiene) and (Z,Z,Z)-3,6,9-heptadecatriene as female-produced sex pheromone components. (Z,Z)-(3R,4S)-3,4-Epoxy-6,9-heptadecadiene elicited a response from male I. argillacearia antennae during EAG recording, and in the Y-tube olfactometer tests males did not discriminate between a live female and (Z,Z)-(3R,4S)-3,4-epoxy-6,9-heptadecadiene. Field-trapping experiments showed that a blend of (Z,Z)-(3R,4S)-3,4-epoxy-6,9-heptadecadiene and (Z,Z,Z)-3,6,9-heptadecatriene was more attractive to male moths than (Z,Z)-(3R,4S)-3,4-epoxy-6,9-heptadecadiene alone.

A pilot study on safety and clinical utility of a single-use 72-hour indwelling transesophageal echocardiography probe

PURPOSE

To evaluate the hemodynamic monitoring capability and safety of a single-use miniaturized transesophageal echocardiography (TEE) probe left in place in ventilated critically ill patients.

METHODS

The probe was inserted in 94 patients and designed to be left in place for up to 72 h. Three views were obtained: the superior vena caval transverse, the mid-esophageal four-chamber, and the transgastric mid-papillary short-axis views. Observational data on the feasibility of insertion, complications, image quality, and influence on management were recorded and analyzed.

RESULTS

No failure of probe insertion was observed. The nasogastric tube had to be removed in 17 % of cases. Image quality was judged as adequate or optimal in 91/94 (97 %) of cases in the superior vena caval view, 89/94 (95 %) of cases in the four-chamber view, and 86/94 (91 %) of cases in the short-axis view. The duration of monitoring was 32 ± 23 h, allowing 2.8 ± 1.6 hemodynamic evaluations per patient that led to a mean of 1.4 ± 1.5 therapeutic changes per patient. Among the 263 hemodynamic assessments, 132 (50 %) had a direct therapeutic impact in 62 patients (66 %). Two patients developed lip ulceration from the probe, and two patients had self-limited gastric bleeding.

CONCLUSION

The single-use miniaturized probe could be inserted in all patients. Image quality was acceptable in the majority of cases, and the information derived from the device was useful in making management decisions in patients with hemodynamic failure on ventilatory support. Further studies are needed to confirm the good tolerance and to compare the new device with other hemodynamic monitoring techniques.

Adequacy of chest compressions performed by medical housestaff

BACKGROUND

Chest compressions (CCs) are a critical part of cardiopulmonary resuscitation. We studied the presence and duration of adequate CCs performed by medical housestaff, and correlated our findings with gender and body mass index.

METHODS

Fifty-eight first-postgraduate-year medical housestaff performed CCs on a computerized patient simulator equipped with a calibrated CC measurement device. Following initial testing, subjects were trained to perform adequate CCs. Subjects were retested 2 weeks later. Presence and duration of adequate CCs were measured during a 120-second endurance test.

RESULTS

Before training, 14/28 (50%) of the male housestaff performed adequate CCs and 0/30 (0%) of the female housestaff performed adequate CCs. After training, 25/28 (89%) of the male housestaff and 16/30 (53%) of the female housestaff performed adequate CCs. Body mass index and height were not related to adequacy of CCs. After training, 7/28 (25%) of the male subjects and 1/30 (3%) of the female subjects were able to maintain adequate CCs for 120 seconds.

CONCLUSIONS

Training housestaff on a patient simulator is an effective means of improving the adequacy of CCs. Despite training, a significant number of women were unable to perform adequate CCs compared with men; body mass index and height were not determining factors. Very few housestaff were able to sustain 120 seconds of adequate CCs, despite training.