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Background and Purpose: Early detection of large vessel occlusion (LVO) stroke optimizes endovascular therapy and improves outcomes. Clinical stroke severity scales used for LVO identification have variable accuracy. We investigated a portable LVO-detection device (PLD), using electroencephalography and somatosensory-evoked potentials, to identify LVO stroke. Methods: We obtained PLD data in suspected patients with stroke enrolled prospectively via a convenience sample in 8 emergency departments within 24 hours of symptom onset. LVO discriminative signals were integrated into a binary classifier. The National Institutes of Health Stroke Scale was documented, and 4 prehospital stroke scales were retrospectively calculated. We compared PLD and scale performance to diagnostic neuroimaging. Results: Of 109 patients, there were 25 LVO (23%), 38 non-LVO ischemic (35%), 14 hemorrhages (13%), and 32 stroke mimics (29%). The PLD had higher sensitivity (80% [95% CI, 74–85]) and similar specificity (80% [95% CI, 77–83]) to all prehospital scales at their predetermined high probability LVO thresholds. The PLD had high discrimination for LVO ( C -statistic=0.88). Conclusions: The PLD identifies LVO with superior accuracy compared with prehospital stroke scales in emergency department suspected stroke. Future studies need to validate the PLD’s potential as an LVO triage aid in prehospital undifferentiated stroke populations.

BackgroundThe HEART Pathway combines a History ECG Age Risk factor (HEAR) score and serial troponins to risk stratify patients with acute chest pain. However, it is unclear whether patients with HEAR scores of <1 require troponin testing. The objective of this study is to measure the major adverse cardiac event (MACE) rate among patients with <1 HEAR scores and determine whether serial troponin testing is needed to achieve a miss rate MethodsA secondary analysis of the HEART Pathway Implementation Study was conducted. HEART Pathway risk assessments (HEAR scores and serial troponin testing at 0 and 3 hours) were completed by the providers on adult patients with chest pain from three US sites between November 2014 and January 2016. MACE (composite of death, myocardial infarction (MI) and coronary revascularisation) at 30 days was determined. The proportion of patients with HEAR scores of <1 diagnosed with MACE within 30 days was calculated. The impact of troponin testing on patients with HEAR scores of <1 was determined using Net Reclassification Improvement Index (NRI).ResultsProviders completed HEAR assessments on 4979 patients and HEAR scores<1 was 97.8% (95%CI 94.5% to 99.4%) and 99.1% (95% CI 97.7% to 99.8%), respectively, and were not improved by troponin testing. Troponin testing in patients with HEAR <1 correctly reclassified two patients diagnosed with MACE, and was elevated among seven patients without MACE yielding an NRI of 0.9% (95%CI −0.7 to 2.4%).ConclusionThese data suggest that patients with HEAR scores of 0 and 1 represent a very low-risk group that may not require troponin testing to achieve a missed MACE rate Trial registration numberNCT02056964

Objective: Use of point-of-care (POC) troponin (cTn) testing in the Emergency Department (ED) is well established. However, data examining POC cTn measurement in the prehospital setting, during amb...

IMPORTANCE: For critically ill adults undergoing emergency tracheal intubation, failure to intubate the trachea on the first attempt occurs in up to 20% of cases and is associated with severe hypoxemia and cardiac arrest. Whether using a tracheal tube introducer (“bougie”) increases the likelihood of successful intubation compared with using an endotracheal tube with stylet remains uncertain. OBJECTIVE: To determine the effect of use of a bougie vs an endotracheal tube with stylet on successful intubation on the first attempt. DESIGN, SETTING, AND PARTICIPANTS: The Bougie or Stylet in Patients Undergoing Intubation Emergently (BOUGIE) trial was a multicenter, randomized clinical trial among 1102 critically ill adults undergoing tracheal intubation in 7 emergency departments and 8 intensive care units in the US between April 29, 2019, and February 14, 2021; the date of final follow-up was March 14, 2021. INTERVENTIONS: Patients were randomly assigned to use of a bougie (n = 556) or use of an endotracheal tube with stylet (n = 546). MAIN OUTCOMES AND MEASURES: The primary outcome was successful intubation on the first attempt. The secondary outcome was the incidence of severe hypoxemia, defined as a peripheral oxygen saturation less than 80%. RESULTS: Among 1106 patients randomized, 1102 (99.6%) completed the trial and were included in the primary analysis (median age, 58 years; 41.0% women). Successful intubation on the first attempt occurred in 447 patients (80.4%) in the bougie group and 453 patients (83.0%) in the stylet group (absolute risk difference, −2.6 percentage points [95% CI, −7.3 to 2.2]; P = .27). A total of 58 patients (11.0%) in the bougie group experienced severe hypoxemia, compared with 46 patients (8.8%) in the stylet group (absolute risk difference, 2.2 percentage points [95% CI, −1.6 to 6.0]). Esophageal intubation occurred in 4 patients (0.7%) in the bougie group and 5 patients (0.9%) in the stylet group, pneumothorax was present after intubation in 14 patients (2.5%) in the bougie group and 15 patients (2.7%) in the stylet group, and injury to oral, glottic, or thoracic structures occurred in 0 patients in the bougie group and 3 patients (0.5%) in the stylet group. CONCLUSIONS AND RELEVANCE: Among critically ill adults undergoing tracheal intubation, use of a bougie did not significantly increase the incidence of successful intubation on the first attempt compared with use of an endotracheal tube with stylet. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03928925

Background Nitrite is reduced by heme-proteins and molybdenum-containing enzymes to form the important signaling molecule nitric oxide (NO), mediating NO signaling. Substantial evidence suggests that deoxygenated hemoglobin within red blood cells (RBCs) is the main erythrocytic protein responsible for mediating nitrite-dependent NO signaling. In other work, infrared and far red light have been shown to have therapeutic potential that some attribute to production of NO. Here we explore whether a combination of nitrite and far red light treatment has an additive effect in NO-dependent processes, and whether this effect is mediated by RBCs. Methods and results Using photoacoustic imaging in a rat model as a function of varying inspired oxygen, we found that far red light (660 nm, five min. exposure) and nitrite feeding (three weeks in drinking water at 100 mg/L) each separately increased tissue oxygenation and vessel diameter, and the combined treatment was additive. We also employed inhibition of human platelet activation measured by flow cytometry to assess RBC-dependent nitrite bioactivation and found that far red light dramatically potentiates platelet inhibition by nitrite. Blocking RBC-surface thiols abrogated these effects of nitrite and far-red light. RBC-dependent production of NO was also shown to be enhanced by far red light using a chemiluminescence-based nitric oxide analyzer. In addition, RBC-dependent bioactivation of nitrite led to prolonged lag times for clotting in platelet poor plasma that was enhanced by exposure to far red light. Conclusions Our results suggest that nitrite leads to the formation of a photolabile RBC surface thiol-bound species such as an S-nitrosothiol or heme-nitrosyl (NO-bound heme) for which far red light enhances NO signaling. These findings expand our understanding of RBC-mediated NO production from nitrite. This pathway of NO production may have therapeutic potential in several applications including thrombosis, and, thus, warrants further study., Graphical abstract Potential mechanism of RBC-mediated nitrite bioactivation and its potentiation by far red light. Nitrite reacts with deoxygenated Hb to make NO which then binds other vacant hemes or forms a nitrosothiol (RSNO). The nitrosyl-heme or nitrosothiol is exported and binds a surface thiol. Another potential NO species that may form is a DNIC (not shown). The NO congener can then be transported in plasma and interact with platelets and other blood components and this action is potentiated by photolysis using far red light.fx1, Highlights • Nitrite and far red light increase tissue oxygenation under hypoxia. • Far red light enhances nitrite-mediated inhibition of platelet activation by red cells. • Blocking red cell surface thiols abrogates nitrite-mediated effects. • NO production from nitrite and red cells is enhanced by far red light. • Lag time in clotting is prolonged by nitrite plus far red light.

Background Contemporary emergency department (ED) standard-of-care treatment of hyperkalemia is poorly described. Objective Our aim was to determine the treatment patterns of hyperkalemia management in the ED. Methods This multicenter, prospective, observational study evaluated patients aged ≥ 18 years with hyperkalemia (potassium [K+] level ≥ 5.5 mmol/L) in the ED from October 25, 2015 to March 30, 2016. K+-lowering therapies and K+ were documented at 0.5, 1, 2, and 4 h after initial ED treatment. The primary end point was change in K+ over 4 h. Results Overall, 203 patients were enrolled at 14 U.S.-based sites. The initial median K+ was 6.3 (interquartile range [IQR] 5.7–6.8) mmol/L and median time to treatment was 2.7 (IQR 1.9–3.5) h post-ED arrival. Insulin/glucose (n = 130; 64%) was frequently used to treat hyperkalemia; overall, 43 different treatment combinations were employed within the first 4 h. Within 4 h, the median K+ for patients treated with medications alone decreased from 6.3 (IQR, 5.8–6.8) mmol/L to 5.3 (4.8–5.7) mmol/L, while that for patients treated with dialysis decreased from 6.2 (IQR 6.0–6.6) mmol/L to 3.8 (IQR 3.6–4.2) mmol/L. Hypoglycemia occurred in 6% of patients overall and in 17% of patients with K+ > 7.0 mmol/L. Hyperkalemia-related electrocardiogram changes were observed in 23% of all patients; 45% of patients with K+ > 7.0 mmol/L had peaked T waves or widened QRS. Overall, 79% were hospitalized; 3 patients died. Conclusions Hyperkalemia practice patterns vary considerably and, although treatment effectively lowered K+, only dialysis normalized median K+ within 4 h.

Objective The HEART Pathway is an evidence-based decision tool for identifying emergency department (ED) patients with acute chest pain who are candidates for early discharge, to reduce unhelpful and potentially harmful hospitalizations. Guided by the Consolidated Framework for Implementation Research, we sought to identify important barriers and facilitators to implementation of the HEART Pathway. Study setting Data were collected at 4 academic medical centers. Study design We conducted semi-structured interviews with 25 key stakeholders (e.g., health system leaders, ED physicians). We conducted interviews before implementation of the HEART Pathway tool to identify potential barriers and facilitators to successful adoption at other regional academic medical centers. We also conducted postimplementation interviews at 1 medical center, to understand factors that contributed to successful adoption. Data collection Interviews were recorded and transcribed verbatim. We used a Consolidated Framework for Implementation Research framework-driven deductive approach for coding and analysis. Principal findings Potential barriers to implementation include time and resource burden, challenges specific to the electronic health record, sustained communication with and engagement of stakeholders, and patient concerns. Facilitators to implementation include strength of evidence for reduced length of stay and unnecessary testing and iatrogenic complications, ease of use, and supportive provider climate for evidence-based decision tools. Conclusions Successful dissemination of the HEART Pathway will require addressing institution-specific barriers, which includes engaging clinical and financial stakeholders. New SMART-FHIR technologies, compatible with many electronic health record systems, can overcome barriers to health systems with limited information technology resources.

We describe a case of proven transmission of SARS-CoV-2 from lung donor to recipient. The donor had no clinical history or findings suggestive of infection with SARS-CoV-2 and tested negative by reverse transcriptase polymerase chain reaction (RT-PCR) on a nasopharyngeal (NP) swab obtained within 48 h of procurement. Lower respiratory tract testing was not performed. The recipient developed fever, hypotension, and pulmonary infiltrates on posttransplant day (PTD) 3, and RT-PCR testing for SARS-CoV-2 on an NP swab specimen was non-reactive, but positive on bronchoalveolar lavage (BAL) fluid. One thoracic surgeon present during the transplantation procedure developed COVID-19. Sequence analysis of isolates from donor BAL fluid (obtained at procurement), the recipient, and the infected thoracic surgeon proved donor origin of recipient and health-care worker (HCW) infection. No other organs were procured from this donor. Transplant centers and organ procurement organizations should perform SARS-CoV-2 testing of lower respiratory tract specimens from potential lung donors, and consider enhanced personal protective equipment for HCWs involved in lung procurement and transplantation.

BACKGROUND: Cardiac dysfunction, a common complication from severe sepsis, is associated with increased morbidity and mortality. However, the molecular mechanisms of septic cardiac dysfunction are poorly understood. SIRT1, a member of the sirtuin family of NAD+-dependent protein deacetylases, is an important immunometabolic regulator of sepsis, and sustained SIRT1 elevation is associated with worse outcomes and organ dysfunction in severe sepsis. Herein, we explore the role of SIRT1 in septic cardiac dysfunction using a murine model of sepsis. METHODS: An in vitro model of inflammation in isolated H9c2 cardiomyocytes was used to confirm SIRT1 response to stimulation with lipopolysaccharide (LPS), followed by a murine model of cecal ligation and puncture (CLP) to investigate the molecular and echocardiographic response to sepsis. A selective SIRT1 inhibitor, EX-527, was employed to test for SIRT1 participation in septic cardiac dysfunction. RESULTS: SIRT1 mRNA and protein levels in cultured H9c2 cardiomyocytes were significantly elevated at later time points after stimulation with LPS. Similarly, cardiac tissue harvested from C57BL/6 mice 36 hours after CLP demonstrated increased expression of SIRT1 mRNA and protein compared to sham controls. Administration of EX-527 18 hours after CLP reduced SIRT1 protein expression in cardiac tissue at 36 hours. Moreover, treatment with EX-527 improved cardiac performance with increased global longitudinal strain and longitudinal strain rate. CONCULSIONS: Our findings reveal that SIRT1 expression increases in isolated cardiomyocytes and cardiac tissue after sepsis-inflammation. Moreover, rebalancing SIRT1 excess in late sepsis improves cardiac performance suggesting that SIRT1 may serve as a therapeutic target for septic cardiomyopathy.

The HEART Pathway is a validated risk stratification protocol for Emergency Department patients with chest pain that has yet to be tested in the prehospital setting. This study seeks to test the performance of a prehospital modified HEART Pathway (PMHP). A prospective cohort study of adults with chest pain without ST-segment elevation myocardial infarction was conducted at three EMS agencies between 12/2016-1/2018. To complete a PMHP assessment, paramedics drew blood, measured point-of-care (POC) troponin (i-STAT; Abbott Point of Care) and calculated a HEAR score. Patients were stratified into three groups: high-risk based on an elevated troponin, low-risk based on a HEAR score

Background Septic cardiomyopathy (SCM) is common in sepsis and associated with increased morbidity and mortality. Left ventricular global longitudinal strain (LV GLS), measured by speckle tracking echocardiography, allows improved identification of impaired cardiac contractility. The peripheral blood transcriptome may be an important window into SCM pathophysiology. We therefore studied the peripheral blood transcriptome and LV GLS in a prospective cohort of patients with sepsis. Results In this single-center observational pilot study, we enrolled adult patients (age > 18) with sepsis within 48 h of admission to the ICU. SCM was defined as LV GLS > − 17% based on echocardiograms performed within 72 h of admission. We enrolled 27 patients, 24 of whom had high-quality RNA results; 18 (75%) of 24 had SCM. The group was 50% female and had a median (IQR) age of 59.5 (48.5–67.0) years and admission APACHE II score of 21.0 (16.0–32.3). Forty-six percent had septic shock. After filtering for low-expression and non-coding genes, 15,418 protein coding genes were expressed and 73 had significantly different expression between patients with vs. without SCM. In patients with SCM, 43 genes were upregulated and 30 were downregulated. Pathway analysis identified enrichment in type 1 interferon signaling (adjusted p −5). Conclusions In this hypothesis-generating study, SCM was associated with upregulation of genes in the type 1 interferon signaling pathway. Interferons are cytokines that stimulate the innate and adaptive immune response and are implicated in the early proinflammatory and delayed immunosuppression phases of sepsis. While type 1 interferons have not been implicated previously in SCM, interferon therapy (for viral hepatitis and Kaposi sarcoma) has been associated with reversible cardiomyopathy, perhaps suggesting a role for interferon signaling in SCM.

IntroductionIntubation-related complications are less frequent when intubation is successful on the first attempt. The rate of first attempt success in the emergency department (ED) and intensive care unit (ICU) is typically less than 90%. The bougie, a semirigid introducer that can be placed into the trachea to facilitate a Seldinger-like technique of tracheal intubation and is typically reserved for difficult or failed intubations, might improve first attempt success. Evidence supporting its use, however, is from a single academic ED with frequent bougie use. Validation of these findings is needed before widespread implementation.Methods and analysisThe BOugie or stylet in patients Undergoing Intubation Emergently trial is a prospective, multicentre, non-blinded randomised trial being conducted in six EDs and six ICUs in the USA. The trial plans to enrol 1106 critically ill adults undergoing orotracheal intubation. Eligible patients are randomised 1:1 for the use of a bougie or use of an endotracheal tube with stylet for the first intubation attempt. The primary outcome is successful intubation on the first attempt. The secondary outcome is severe hypoxaemia, defined as an oxygen saturation less than 80% between induction until 2 min after completion of intubation. Enrolment began on 29 April 2019 and is expected to be completed in 2021.Ethics and disseminationThe trial protocol was approved with waiver of informed consent by the Central Institutional Review Board at Vanderbilt University Medical Center or the local institutional review board at an enrolling site. The results will be submitted for publication in a peer-reviewed journal and presented at scientific conferences.Trial registration numberClinicalTrials.gov Registry (NCT03928925).

Photoacoustic (PA) imaging is an emerging technology that combines structural and functional imaging of tissues using laser and ultrasound energy. We evaluated the ability of PA imaging system to measure real-time systemic and microvascular mean oxygen saturation (mSAO2) in a rat model of hypoxic shock. Male Sprague Dawley rats (n = 6) underwent femoral artery catherization and were subjected to acute hypoxia by lowering the fraction of inspired oxygen (FiO2) from 1.0 to 0.21, and then to 0.08. PA measurements of mSaO2 were taken in the femoral artery near the catheter tip using the Vevo 2100 LAZR at each FiO2 and compared to co-oximetry on blood removed from the femoral catheter. Both co-oximetry and PA imaging measured a similar stepwise decline in femoral artery mSaO2 as FiO2 was lowered. We also measured mSaO2 in the feed arteriole of the rat spinotrapezius muscle and adjacent microvessels (n = 6) using PA imaging. A significant decrease in mSaO2 in both the feed arteriole and adjacent microvessels was recorded as FiO2 was decreased from 1.0 to 0.08. Moreover, we detected a rapid return toward baseline mSaO2 in the feed arteriole and microvessels when FiO2 was increased from 0.08 to 1.0. Thus, PA imaging is noninvasive imaging modality that can accurately measure real-time oxygen saturation in the macro and microcirculation during acute hypoxia. This proof-of-concept study is a first step in establishing PA imaging as an investigational tool in critical illness.

Placental oxygenation varies throughout pregnancy. The detection of early changes in placental oxygenation as pregnancy progresses is important for early identification of preeclampsia or other complications. This invited commentary discusses a recent preclinical study on the application of 3-dimensional photoacoustic imaging (PAI) for assessment of regional variations in placental oxygenation and longitudinal analysis of differences in placental oxygenation throughout normal pregnancy and pregnancy associated with hypertension or placental insufficiency in mice. Three-dimensional PAI more accurately reflects oxygen saturation, hemoglobin concentrations, and changes in oxygen saturation in whole placenta compared to 2-dimensional imaging. These studies suggest that PAI is a sensitive tool to detect different levels of oxygen saturation in the placental and fetal vasculature in pathologic and normal pregnancy in mice.

Introduction Patient satisfaction is a key indicator of health care value and an increasingly important metric used to assess emergency physician performance and often reimbursement. To our knowledge, there is no standardized curriculum within emergency medicine (EM) residency programs that focuses on the patient experience in EM. Methods Our novel resident curriculum is an organized approach to enhancing patient-centered care by optimizing the patient experience. It spans the academic year, with key topics organized into a quarterly time line. Topics include physician courtesy and respect, pain management, discussion of diagnostic and therapeutic interventions, timely communication, and delivery of quality care. Each quarter has three components: introduction/didactics, an interactive workshop, and stories and reflection. The instructional methods used include didactic lectures, role-playing, and group reflection and storytelling. Results Of 44 participants, 54.5% completed a preintervention survey, and 45.5% completed a postintervention survey. The surveys consisted of 5-point Likert scales measuring degree of agreement with statements that reflected desired behaviors and/or attitudes. On the postintervention survey, participants gave scores indicating general agreement with desired behaviors including sitting at the bedside, acknowledging all persons in the room, and giving an anticipated disposition, as well as with feeling more knowledgeable about patient satisfaction. Discussion Our Satisfaction Academy has filled a significant gap related to enhancing the patient experience. This curriculum is generalizable to other EM residency programs, and the interactive peer-to-peer format is both engaging and customizable.

Background Pulmonary contusion (PC) is a common injury that often results in priming for exaggerated inflammatory responses to a second hit. Previous studies used a mouse model of pulmonary contusion and showed an early and sustained reduction of SIRT1 protein and activity in the lung and bronchoalveolar lavage (BAL) cells of injured mice. Sustained decrease in SIRT1 was associated with a primed phenotype in injured mice challenged with an inflammatory stimulus. This study tests the hypothesis that pulmonary contusion induces oxidant production that modifies and decreases SIRT1 and primes the lung for the second-hit response. Methods A mouse model of pulmonary contusion was used to investigate injury-induced oxidant changes in SIRT1. Second-hit responses were evaluated by infection (Streptococcus pneumoniae) and inflammatory challenge using bacterial lipopolysaccharide. BAL, lung tissue, and blood were collected and used to evaluate inflammatory responses and SIRT1 levels, oxidant modification, and activity. Levels of NO in the BAL from mice and patients with PC were also assessed. Results We found that oxidants produced as a result of pulmonary contusion resulted in modification of SIRT1. S-Nitrosylation was observed and correlated with increased inducible nitric oxide synthase expression after injury. Anti-oxidant treatment of injured mice preserved SIRT1 activity, decreased second hit responses and improved lung function. Elevated NO levels in the BAL of PC patients was associated with acute respiratory distress syndrome or diagnosis of pneumonia. Conclusions We conclude that oxidative stress in the lung after injury induces redox modification of SIRT1 and contributes to priming of the lung for a second-hit response. Antioxidant treatment suggests that SIRT1 activity after injury may be beneficial in suppressing second-hit responses.

Pulmonary contusion (PC) is a common, potentially lethal injury that results in priming for exaggerated inflammatory responses to subsequent immune challenge like infection (second hit). The molecular mechanism of priming and the second hit phenomenon after PC remain obscure. With the use of a mouse model of PC, this study explores the role of sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, in priming for a second hit after injury.With the use of a mouse model of PC, injury-primed second-hit host responses were tested at 24 hours after PC by (1) in vivo infectious challenge of injured mice or (2) ex vivo inflammatory challenge of isolated immune cells from injured mice. SIRT activators or repressors were used to test for SIRT1 participation in these second-hit responses.PC-injured mice given an in vivo infectious challenge by cecal ligation and puncture (CLP) had significantly increased mortality compared with injury or infectious challenge alone. Isolated bronchoalveolar lavage (BAL) cells from injured mice given an ex vivo inflammatory challenge with bacterial lipopolysaccharide (LPS) had increased levels of tumor necrosis factor α messenger RNA compared with uninjured mice. We found that PC reduced SIRT1 protein, messenger RNA, and SIRT1 enzymatic activity in injured lung tissue. We also found decreased SIRT1 protein levels in BAL cells from injured mice. We further found that injured mice treated with a SIRT1 activator, resveratrol, showed significantly decreased polymorphonuclear leukocytes (PMN) in the BAL in response to intratracheal LPS and increased survival from CLP.These results showed that PC decreased SIRT1 levels in the lung correlated with enhanced responses to infectious or inflammatory stimuli in injured mice. Treatment of injured mice with a SIRT1 activator, resveratrol, decreased LPS inflammatory response and increased survival after CLP. Our results suggest that SIRT1 participates in the second-hit response after injury.

We tested the hypothesis that a deficit in oxygen extraction or an increase in oxygen demand after skeletal muscle contraction leads to delayed recovery of tissue oxygen tension (Po2) in the skeletal muscle of hypertensive rats compared with normotensive rats. Blood flow and Po2 recovery at various sites in the spinotrapezius muscle of spontaneously hypertensive rats (SHRs) were evaluated after a 3-min period of muscle contraction and were compared with corresponding values in Wistar-Kyoto rats (WKYs). The recovery of tissue Po2 [75 ± 7 (SHRs) vs. 99 ± 12% (WKYs) of resting values] and venular Po2 [72 ± 13 (SHRs) vs. 104 ± 10% (WKYs) of resting values] were significantly depressed in the SHRs 30 s postcontraction. The delayed recovery persisted for 120 s postcontraction for both tissue [86 ± 11 (SHRs) vs. 119 ± 13% (WKYs) of resting values] and venular [74 ± 2 (SHRs) vs. 100 ± 9% (WKYs) of resting values] Po2 levels. There was no significant difference in the recovery of arteriolar Po2 between the two groups 30 s postcontraction [95 ± 7 (SHRs) vs. 84 ± 8% (WKYs) of resting values]. Values for resting diameter of arcade arterioles in the two groups were not different [52 ± 3 (SHRs) vs. 51 ± 3 μm (WKYs)], but the arteriolar diameter after the 3-min contraction period was greater in the SHRs (71 ± 4 μm) than the WKYs (66 ± 4). Likewise, red blood cell (RBC) velocity [5.8 ± 0.3 (SHRs) vs. 4.7 ± 0.2 mm/s (WKYs)] and blood flow [23.0 ± 0.8 (SHRs) vs. 16.0 ± 1.0 nl/s (WKYs)] measurements were significantly greater in the SHRs at 30 s postcontraction. The delayed recovery of tissue Po2 in the SHRs compared with the WKYs can be explained by a decrease in oxygen diffusion from the rarefied microvascular network due to the increased RBC velocity and the shorter residence time in the microcirculation and the consequent disequilibrium for oxygen between plasma and RBCs. The delayed recovery of venular Po2 in the SHRs is consistent with this explanation, as venular Po2 is slowly restored to baseline by release of oxygen from the RBCs. This leaves the arterioles in the primary role as oxygen suppliers to restore Po2 in the tissue after muscle contraction.

This study introduces the technique of microinjection of phosphor probe into skeletal muscle tissue to determine oxygen tension (PO(2)) in the interstitium by phosphorescence quenching microscopy.The spinotrapezius muscle of Wistar-Kyoto rats weighing 240-280 g was surgically isolated and underwent the microinjection procedure. We measured the spatial distribution of phosphor probe 10, 30, and 80 minutes after injection; the tissue PO(2) at sites adjacent to arteriolar and venular microvessels; and the decline in tissue PO(2) during a 3-minute period of 8-Hz contraction.The phosphorescence signal from the probe was undetectable outside a 2.5-mm radius from the site of injection at the 10-minute time point, increased to measurable values after 30 minutes, and was double the 30-minute intensity value after 80 minutes. When used to measure periarteriolar PO(2), the tissue microinjection technique demonstrated a nonlinear fall in tissue PO(2) with distance away from secondary arterioles (30-40 microm diameter). Conversely, perivenular tissue PO(2) increased in a nonlinear manner with distance away from secondary venules (60-70 microm diameter). The tissue PO(2) at distances of 16 microm and greater from both types of secondary microvessels was significantly different from values taken directly over the centerline of these microvessels. During muscle contraction, the PO(2) fell from a mean precontraction value of 28.3 +/- 4.9 mmHg to 8.2 +/- 0.9 mmHg at the end of the contraction period.These observations indicate that the microinjection technique yields values for tissue PO(2) that are in good agreement with previously published results using oxygen microelectrodes.

▪ Abstract The smokybrown cockroach, Periplaneta fuliginosa (Serville), has become an increasingly important peridomestic pest throughout much of the southeastern United States, Japan, and southeast Asia. We provide a brief description of the species and clarify its worldwide distribution. Aspects of smokybrown cockroach behavior, biology, ecology, and physiology are discussed in the context of this species' successful exploitation of the urban environment. We describe smokybrown cockroach management based upon a model that relates house and landscape characteristics to cockroach population size. Finally, we illustrate the effectiveness of a model-based IPM system that increases control while reducing use of insecticides.

As adult male American, Periplaneta americana (L.), and smokybrown, Periplaneta fuliginosa (Serville), cockroaches dehydrated, their preference for water-vapor saturation deficits changed. Cockroach preference was tested in paired arenas with controlled temperature and relative humidity (i.e., water-vapor saturation deficits) in each arena. Hydrated P. americana males preferred greater water-vapor saturation deficits (i.e., warmer and drier conditions), whereas males denied water for 14 d preferred lower saturation deficit (i.e., cooler and more moist conditions). However, hydrated P. fuliginosa males showed no preference; males denied water for 7 d preferred lower saturation deficits similar to P. americana males at 14 d. Preference increased nonlinearly as the difference in saturation deficit between paired arenas increased. Median mortality time decreased with increasing saturation deficit. Preferences and mortality may be indicative of the differing physiological ecology of these 2 cockroach species.

Repellency of moving ambient air to American, Periplaneta americana (L.), and smokybrown, Periplaneta fuliginosa (Serville), cockroaches was evaluated with modified Ebeling choice boxes by using air velocities of 0-4.75 m/s. All measured stages (adult female and male, and medium and large nymphs) of both species were significantly repelled by air velocities greater than or equal to 4.0 m/s. Percentage of repellency increased exponentially with air velocity for American, but increased linearly for smokybrown cockroaches. Male American cockroaches detect moving air with mechanoreceptors located on their antennae and cerci. Differences in response to air velocity may help explain the absence of smokybrown cockroaches from sewerage systems. Moving air maybe useful as a noninsecticidal tactic in an integrated pest management system for American and smokybrown cockroach control.

Targeted and conventional (perimeter spray) insecticide application strategies were compared in 3 geographically distinct urban areas of Alabama. Cockroach abundance in sticky traps did not correspond to the known north-south climate gradient in Alabama. Greatest mean catch was in Mobile, and least in Auburn. Despite varying environmental and ecological conditions across Alabama, similar reductions and recovery rates of smokybrown cockroach abundance were observed in all 3 urban areas for 3 different treatments (perimeter spray, targeted spray, and 2-bait combination). A 2-bait combination was more effective in reducing smokybrown cockroach catch than a conventional perimeter spray, whereas a 3-liter targeted spray performed as well as perimeter sprays. Less insecticide was applied using targeted applications than perimeter sprays. Targeted applications of either baits or sprays did not require significantly more time to apply than a perimeter spray.

A modified Ebeling choice box was designed to evaluate the repellency of Moving ambient air to German cockroaches, Blattella germanica (L.), determine how German Cockroach detect moving air, and evaluate the potential of moving air to change the distribution pattern of German cockroach populations. The modified choice box tested the repellency of moving air relative to light. All stages (adult male, adult gravid and nongravid female, and small/medium and large nymphs) were significantly repelled by air velocities ≥2.0 m/s, and percentage of repellency increased linearly with air velocity between 0.75 and 4.0 m/s. German cockroaches detect moving air with their antennae using mechanoreceptors. Application of moving air in simulated kitchen cabinets changed significantly the distribution pattern of mixed-stage groups of German cockroaches. Moving air, at relatively low velocities, could be a useful as a noninsecticidal tactic in integrated pest management system for German cockroach control.

We tested the hypothesis that presence and color of shed follicles in ovarioles of smokybrown cockroaches, Periplaneta fuliginosa (Serville), were correlated with the number of oothecae deposited in the laboratory. There were no shed follicles in females not having oviposited, whereas all females that had deposited 1-4 oothecae had shed follicles or resorption bodies, and females that had deposited greater than or equal to 5 oothecae had only shed follicle cells in the base of ovarioles. Other important correlates of female age (days after adult eclosion) were abdominal fat-free, thoracic fat and fat-free masses, and leg fat mass. Oocyte length could be substituted for oocyte fat and fat-free mass because these variables were correlated with oocyte length. Crop mass and delay in dissection after oothecal deposition were not correlated to female age or number of oothecae. Mass of body fractions (fat and fat-free) increased as females deposited additional oothecae. A generalized linear model predicted that as thoracic fat mass increased the number of oocytes already deposited by a female increased. In addition, the model predicted that red follicles would be found in females having deposited 1-3 oothecae and yellow follicles were predicted to be found in females having deposited >2 oothecae.

Commercial formulations of insecticidal baits were evaluated in laboratory studies against the American cockroach, Periplaneta americana (L.), and the smokybrown cockroach, P. fuliginosa (Serveille). Continuous exposure toxicity tests and Ebeling choice box tests showed that these cockroach species are killed rapidly by most of the tested baits. For American cockroaches in choice boxes, the order of bait toxicity was GOLD CREST (chlorpyrifos) 18 d) consumed more than their own dry mass after 48 h exposure to several baits. Both species differed in initial percentage of body fat, but as period of starvation increased, percentage of fat decreased. Values of R, the correlation coefficient, suggested that percentage of fat might be a better indicator of the amount of bait eaten compared with the period of starvation ( R = -0.86 and 0.82, respectively). GOLD CREST bait was eaten significantly less than dog food (the experimental control) by American cockroaches, and MAXFORCE was eaten significantly less than dog food by smokybrown cockroaches.

The relationship between smokybrown cockroach, Periplaneta fuliginosa (Serville), abundance and habitat was quantified using canonical correlation. Cockroach habitat was described, using 18 house and landscape characteristics based on a sample of 60 homes. Cockroach abundance, estimated by three monthly mean trap catches at each home, was correlated With habitat. After preliminary analysis, only 11 of the house and landscape characteristics were retained in the model. No characteristics dominated the description of habitat (an index) but some contributed positively and others negatively. The characteristics having the largest standardized weights in the habitat index were percentage of lot occupied by home, tree density, number of pets, number of residents, chemical pest control, age of house, and obvious cockroach harborages on tilt' property. Unbiased estimates of variables weights of the habitat index obtained by the Jackknife method demonstrated the fit of the model and revealed minimal effect of outliers; of 14 weights, 11 had standard deviations

Periplaneta fuliginosa (Serville) were collected from Clemson, SC, in the Piedmont region, and Charleston, SC, in the coastal region. Maximal developmental rates of eggs and number of nymphs emerging from oothecae hatching at five temperature increments (15, 20, 25, 30, and 35°C) were recorded in the laboratory for each population. Developmental rates were also recorded for the first male and female to mature from 1-d-old nymphs hatched from the same ootheca. For first females, preoviposition (time to first ootheca) and oviposition rates, egg developmental rate, and number of nymphs emerged were recorded. Between 20 and 30°C, coastal nymphs developed 5% faster than Piedmont nymphs. At 15°C, only eight cockroaches reached adulthood after 56 mo. Oviposition and preoviposition rates of the coastal population were about 25% faster. Biologically these differences appear insignificant because they are less than variation in literature values. From data pooled from this experiment and the literature, coefficients of the Sharpe-DeMichele developmental rate model were calculated for egg and nymphal development, preoviposition, and oviposition. The regressions had high r 2 values and provide a quantitative basis for understanding population processes in this insect.

Behavior and reproduction of potato leafhopper, Empoasca fabae (Harris) (Homoptera: Cicadellidae), were examined in the laboratory in response to varying densities of leafhoppers, a host legume (alfalfa, Medicago sativa L.), and a non-host grass (large crabgrass, Digitaria sanguinalis L.). A series of caged treatments with increasing crabgrass density per cage resulted in a corresponding series of decreasing oviposition and decreasing number of primary oocytes per female. Oviposition and number of primary oocytes were reduced by approximately 30% at the highest grass density. However, adult activity as measured by percentage of leafhoppers observed on alfalfa, in flights per minute, and on sides of cage, remained unchanged with increasing crabgrass density. When responses given at crabgrass densities were compared with pure alfalfa of equivalent vegetation density (plant surface area), activity in the presence of crabgrass was two to four times larger than alfalfa alone of equivalent vegetation density, with the highest increases occurring after 1700 h and with greatest crabgrass density. Results suggest that greater relative activity induced by crabgrass volatiles may have been responsible for reduced oviposition and reduced tenure time on alfalfa nearest to crabgrass in two-choice tests.

The effect of non-host crabgrass, Digitaria sanguinalis (L.) Scop., on potato leafhopper, Empoasca fabae (Harris) (Homoptera: Cicadellidae), utilization of alfalfa, Medicago sativa L., as host was investigated in binary choice experiments that measured oviposition and residency preference of adults. Leafhoppers preferred to oviposit and reside on pure alfalfa over alfalfa mixed with crabgrass. Successive experiments in which crabgrass was presented to leafhoppers with fewer sensory cures (i.e. tactile, gustatory, visual, olfactory) demonstrated that olfactory cues alone from crabgrass may explain the lower preference equally as well as any combination of other cues. Thus, volatile chemicals from crabgrass reduced acceptability of alfalfa for the potato leafhopper, although visual stimuli are not completely excluded. Additional experiments showed that leafhopper density, lighting, and alfalfa density all may influence leafhopper host utilization in laboratory experiments.

The feeding behavior of 3rd instar gypsy moth (Lymantria dispar L. [Lepidoptera: Lymantriidae]) was examined on foliage from black cherry (Prunus seratina L.) and yellow-poplar (Liriadendran tulipifera L.) seedlings exposed to 71 ± 31, 212 ± 37, and 337 ± 31 μg m−3 ozone (O3) for 70 hours to gauge the effect of O3 stress on host acceptability. Normally, black cherry is a suboptimal food source and yellow-poplar is unacceptable. With feeding preference assays conducted in the laboratory using feeding arenas, the leaf area consumption of black cherry control foliage (exposed to ambient air containing 71 μg m−3 O3) by starved larvae was approximately twice that of yellow-poplar control foliage during the first 4 hours. By 8 hours, the leaf area consumed was the same for both species. O3-treated leaves of both species were preferred by the larvae relative to leaves exposed to ambient concentrations. The effect was pronounced for yellow-poplar, where consumption of ozonated foliage was more than twice that of the control, and its acceptability was enhanced to a level approximating that of black cherry.

The purpose of this study was to correlate microvascular oxygen delivery (DO2) and consumption (VO2) in the skeletal muscle of spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKY) with hemodynamics during acute hypoxia. We expected greater abnormalities in central and microvascular hemodynamics during hypoxic induced shock in the SHR compared with the WKY due to microvascular rarefaction. The inspired oxygen fraction (FiO2) was lowered from 0.21 to 0.15, 0.1, 0.08, and 0.05 in anesthetized, mechanically ventilated rats. Lactate and base deficit values were similar for both groups at 0.21 and 0.15 FiO2, but higher in SHR at lower FiO2. Baseline aortic blood flow (SHR, 56.2+/-4.0 mL min; WKY, 61.8+/-5.3 mL min) and systemic DO2 (SHR, 9.02+/-0.82 mL min; WKY, 9.32+/-0.54 mL min) increased similarly when FiO2 was lowered to 0.15. Further reductions in FiO2 caused lower aortic flow and systemic DO2 in the SHR than WKY at 0.08 and 0.05 FiO2. Spinotrapezius blood flow increased from baseline (SHR, 24.8+/-1.8 nL s; WKY, 22.7+/-2.1 nL s) in both groups when FiO2 was reduced to 0.15; further reductions in FiO2 decreased blood flow in both groups, with lower values in the SHR group at 0.1 and 0.08 FiO2. The SHR group demonstrated higher venous oxygen saturation at low values of FiO2 compared with WKY. This reduced oxygen extraction in SHR resulted in a lower supply-dependent VO2 at low values of spinotrapezius DO2, perhaps attributed to arteriolar thickening and rarefaction seen in chronic hypertension.

The insecticide components of a previously developed integrated pest management system for smokybrown cockroaches, Periplaneta fuliginosa (Serville), were tested individually and at reduced application rates in 4 separate trials over 2 yr. A 2-bait combination (pellet and gel baits) did not significantly reduce cockroach abundance more than a single constituent bait alone. A targeted spray of trelamethrin was significantly less effective than a 2-bait combination. Residual activity of insecticides was determined with American cockroaches, P. americana (L.), in a laboratory bioassay. Chlorpyrifos wettable powder remained active12 d in the field, after which time its activity was not different from an experimental control (no insecticide residues), whereas chlorpyrifos pellet and hydramethylnon paste baits retained initial activity for27 d. Nematodes [Steinernema carpocapsae (Weiser)] applied as a spray solution did not effect the abundance of smokybrown cockroaches, and no cockroaches were recovered that exhibited nematode infection. Time needed to apply various insecticide treatments did not differ substantially (15-25 min per house), even for lower application rates.

Four commercial sticky traps were compared with jar traps for sampling smokybrown cockroaches, Periplaneta fuliginosa (Serville), outdoors. Lo-Line and Raid Roach Traps caught more cockroaches than jar traps, whereas the Mr. Sticky and Roach Motel caught40% of the cockroaches caught in jar traps. Sampling properties of traps (data collected over 4 yr and 3 cities) were examined retrospectively. Taylor's a and b coefficients were both significantly1 for jar traps, Raid Roach Trap, and Lo-Line trap. Estimating cockroach catch typical of Alabama (3 per trap) at single houses would require20 traps with a precision of 0.25 (i.e., standard error as a proportion of the mean). Taylor's power law was also used as a predictor for within-house (i.e., pooled within-house) and between-house catch variances. Coefficients for these predictors are presented that can be used in a fixed-precision 2-stage sampling plan to estimate cockroach catch from large areas.

Two treatments were compared for effectiveness in reducing abundance of smokybrown cockroaches, Periplaneta fuliginosa (Serville), around houses; an integrated pest management strategy consisting of sanitation, landscape management, and reduced insecticide usage, and a perimeter insecticide treatment applied according to label directions. Regression of means through time indicated that the integrated pest management treatment lasted approximately 60 d, whereas the perimeter treatment lasted only 30 d. The greater duration of control in the integrated pest management treatment was likely the result of decreased abundance of cockroaches outside the spray zone. In the perimeter treatment, cockroach abundance was unaffected outside the spray zone with no reduction in adult abundance in the spray zone except in the week following treatment application. The difference between the integrated pest management and perimeter treatments suggests that reinvasion of cockroaches from peripheral habitats decreases the duration of cockroach suppression. Abundance of 1st instars and small and medium nymphs was reduced for the duration of the experiment by both methods. Sampling procedures did not influence cockroach abundance. Reduction in abundance of cockroaches outside of houses reduced abundance of cockroaches inside houses.

Influence of temperature on development and mortality of immature stages of Rhinocyllus conicus Froelich was investigated under different constant temperatures in the laboratory. Development time functions based on the parabola were used to model the data. Because the larvae develop within musk thistle ( Carduus thoermeri Weinmann) heads, developmental times of the larvae were measured indirectly. Determination of the four larval stages of R. conicus was based on distribution of head-capsule sizes of field-collected larvae. Hatching threshold was 11°C and threshold temperatures for development were 16–20°C for the different larval and pupal stages. This temperature range may be an adaptation of R. conicus for synchronization with musk thistle. Highest mortalities for immature stages of R. conicus occurred in the first and fourth instars.