Sex differences in guideline-consistent diagnostic testing for acute pulmonary embolism among adult emergency department patients aged 18-49

BACKGROUND

Pulmonary embolism (PE) is a frequent diagnostic consideration in emergency department (ED) patients, yet diagnosis is challenging because symptoms of PE are nonspecific. Guidelines recommend the use of clinical decision tools to increase efficiency and avoid harms from overtesting, including D-dimer screening in patients not at high risk for PE. Women undergo testing for PE more often than men yet have a lower yield from testing. Our study objective was to determine whether patient sex influenced the odds of received guideline-consistent care.

METHODS

We performed a retrospective cohort study at two large U.S. academic EDs from January 1, 2016, to December 31, 2018. Nonpregnant patients aged 18-49 years were included if they presented with chest pain, shortness of breath, hemoptysis, or syncope and underwent testing for PE with D-dimer or imaging. Demographic and clinical data were exported from the electronic medical record (EMR). Pretest risk scores were calculated using manually abstracted EMR data. Diagnostic testing was then compared with recommended testing based on pretest risk. The primary outcome was receipt of guideline-consistent care, which required an elevated screening D-dimer prior to imaging in all non-high-risk patients.

RESULTS

We studied 1991 discrete patient encounters; 37% (735) of patients were male and 63% (1256) were female. Baseline characteristics, including revised Geneva scores, were similar between sexes. Female patients were more likely to receive guideline-consistent care (70% [874/1256] female vs. 63% [463/735] male, p < 0.01) and less likely to be diagnosed with PE (3.1% [39/1256] female vs. 5.3% [39/735] male, p < 0.05). The most common guideline deviation in both sexes was obtaining imaging without a screening D-dimer in a non-high-risk patient (75% [287/382] female vs. 75% [205/272] male).

CONCLUSIONS

In this cohort, females were more likely than males to receive care consistent with current guidelines and less likely to be diagnosed with PE.

Venous Thromboembolism During Pregnancy and the Postpartum Period: Risk Factors, Diagnostic Testing, and Treatment

Importance

The risk of venous thromboembolism (VTE) increases during pregnancy and the postpartum period. Deep vein thrombosis is the most common VTE during pregnancy, but pulmonary embolism is typically of greater concern as it contributes to far higher morbidity and mortality. Diagnosis and treatment of VTE during pregnancy differ substantially from the general nonpregnant population.

Objective

This review describes the epidemiology, risk factors, clinical presentation, diagnosis, and treatment of VTE during pregnancy and the postpartum period.

Evidence Acquisition

First, we reviewed the VTE guidelines from professional societies in obstetrics, cardiology, hematology, emergency medicine, pulmonology, and critical care. Second, we examined references from these documents and used PubMed to identify recent articles that cited the guidelines. Finally, we searched PubMed and Google Scholar for articles published since 2018 that included terms for pregnancy and the epidemiology, risk factors, diagnostic imaging, or treatment of VTE.

Results

Venous thromboembolism risk increases throughout pregnancy and peaks shortly after delivery. More than half of pregnancy-related VTE are associated with thrombophilia; other major risks include cesarean delivery, postpartum infection, and the combination of obesity with immobilization. Most VTE can be treated with low molecular weight heparin, but cases of limb- or life-threatening VTE require consideration of thrombolysis and other reperfusion therapies.

Conclusions and Relevance

Venous thromboembolism is far more frequent in antepartum and postpartum women than age-matched controls, and clinical suspicion for VTE in this population should incorporate pregnancy-specific risks. Treatment of limb- or life-threatening antepartum or postpartum VTE requires multispecialty coordination to optimize maternal and fetal outcomes.

Field Trauma Triage among Older Adults: A Cost-Effectiveness Analysis

BACKGROUND

National guidelines for prehospital trauma triage aim to identify seriously injured patients who may benefit from transport to trauma centers. These guidelines have poor sensitivity for serious injury among older adults. We evaluated the cost-effectiveness of a high-sensitivity triage strategy for older adults.

STUDY DESIGN

We developed a Markov chain Monte Carlo microsimulation model to estimate the cost-effectiveness of high-sensitivity field triage criteria among older adults compared with current practice. The model used a retrospective cohort of 3621 community-dwelling Medicare beneficiaries who were transported by emergency medical services after an acute injury in 7 counties in the northwestern US during January to December 2011. These data informed model estimates of emergency medical services triage assessment, hospital transport patterns, and outcomes from index hospitalization up to 1 year after discharge. Outcomes beyond 1 year were modeled using published literature. Differences in cost and quality-adjusted life years (QALYs) were calculated for both strategies using a lifetime analytical horizon. We calculated the incremental cost-effectiveness ratio (cost per QALY gained) to assess cost-effectiveness, which we defined using a threshold of less than $100,000 per QALY.

RESULTS

High-sensitivity trauma field triage for older adults would produce a small incremental benefit in average trauma system effectiveness (0.0003 QALY) per patient at a cost of $1,236,295 per QALY. Sensitivity analysis indicates that the cost of initial hospitalization and emergency medical services adherence to triage status (ie transporting triage-positive patients to a trauma center) had the largest influence on overall cost-effectiveness.

CONCLUSIONS

High-sensitivity trauma field triage is not cost-effective among older adults.

Patient-reported Outcomes Among Vulnerable Populations in the Medicare Bundled Payments for Care Improvement Initiative

BACKGROUND

The Centers for Medicare & Medicaid Services Bundled Payments for Care Improvement (BPCI) initiative tested whether episode-based payment models could reduce Medicare payments without harming quality. Among patients with vulnerabilities, BPCI appeared to effectively reduce payments while maintaining the quality of care. However, these findings could overlook potential adverse patient-reported outcomes in this population.

RESEARCH DESIGN

We surveyed beneficiaries with 4 characteristics (Medicare-Medicaid dual eligibility; dementia; recent institutional care; or racial/ethnic minority) treated at BPCI-participating or comparison hospitals for congestive heart failure, sepsis, pneumonia, or major joint replacement of the lower extremity. We estimated risk-adjusted differences in patient-reported outcomes between BPCI and comparison respondents, stratified by clinical episode and vulnerable characteristic.

MEASURES

Patient care experiences during episodes of care and patient-reported functional outcomes assessed roughly 90 days after hospitalization.

RESULTS

We observed no differences in self-reported functional improvement between BPCI and comparison respondents with vulnerable characteristics. Patient-reported care experience was similar between BPCI and comparison respondents in 11 of 15 subgroups of clinical episode and vulnerability. BPCI respondents with congestive heart failure, sepsis, and pneumonia were less likely to indicate positive care experiences than comparison respondents for at least 1 subgroup with vulnerabilities.

CONCLUSIONS

As implemented by hospitals, BPCI Model 2 was not associated with adverse effects on patient-reported functional status among beneficiaries who may be vulnerable to reductions in care. Hospitals participating in heart failure, sepsis or pneumonia bundled payment episodes should focus on patient care experience while implementing changes in care delivery.

Outpatient Treatment of Low-risk Pulmonary Embolism in the Era of Direct Oral Anticoagulants: A Systematic Review

BACKGROUND

Clinical guidelines have supported outpatient treatment of low-risk pulmonary embolism (PE) since 2014, but adoption of this practice has been slow. Direct oral anticoagulant (DOAC) therapy for venous thromboembolism (VTE) is now as common as vitamin K antagonist treatment, but data are sparse regarding outcomes for patients with low-risk PE treated with DOACs as outpatients. We conducted a systematic review of literature on outcomes of outpatient management for PE, including comparisons to inpatient treatment and differences by anticoagulant class.

METHODS

We searched Medline, Embase, PubMed, CENTRAL, clinicaltrials.gov, and ICTRN for studies published from January 1980 through February 2019 using a predefined strategy developed with a medical librarian. We included English-language randomized controlled trials (RCTs) and prospective nonrandomized trials (NRTs) of adult patients diagnosed with acute, symptomatic PE, and discharged from the emergency department or within 48 hours. Our primary outcome included four major adverse outcomes (all-cause mortality, PE-related mortality, recurrent VTE, and major bleeding) within 30 and 90 days. A preplanned subanalysis of high-quality studies assessed outcomes associated with different anticoagulation treatment classes.

RESULTS

Our initial search identified 6,818 records, of which 12 studies (four RCT, eight NRT) with a total of 3,191 patients were included in the review. All RCTs and six NRTs were determined to have low to moderate risk of bias and were classified as high quality. Outpatients in these studies (n = 1,814) had rates of 90-day major adverse outcomes below 1%, including all-cause mortality (0.7%, 95% confidence interval [CI] = 0.4% to 1.2%), PE-related mortality (0.06%, 95% CI = 0.01% to 0.3%), recurrent VTE (0.8%, 95% CI = 0.5% to 1.4%), and major bleeding (0.8%, 95% CI = 0.5% to 1.4%). Exploratory analysis revealed no association between anticoagulant treatment class and rates of major adverse outcomes.

CONCLUSION

Among patients with low-risk PE treated as outpatients, few patients experienced major adverse outcomes such as mortality, recurrent VTE, or major bleeding within 90 days.

Crucial considerations: Sex differences in the epidemiology, diagnosis, treatment, and outcomes of acute pulmonary embolism in non-pregnant adult patients

Acute pulmonary embolism (PE) affects over 600,000 Americans per year and is a common diagnostic consideration among emergency department patients. Although there are well-documented differences in the diagnosis, treatment, and outcomes of cardiovascular conditions, such as ischemic heart disease and stroke, the influence of sex and gender on PE remains poorly understood. The overall age-adjusted incidence of PE is similar in women and men, but women have higher relative rates of PE during early and mid-adulthood (ages 20-40 years); whereas, men have higher rates of PE after age 60 years. Women are tested for PE at far higher rates than men, yet women who undergo computed tomography pulmonary angiography are ultimately diagnosed with PE 35%-55% less often than men. Among those diagnosed with PE, women are more likely to have severe clinical features, such as hypotension and signs of right ventricular dysfunction. When controlled for PE severity, women are less likely to receive reperfusion therapies, such as thrombolysis. Finally, women have more bleeding complications for all types of anticoagulation. Further investigation of possible sex-specific diagnostic and treatment algorithms is necessary in order to more accurately detect and treat acute PE in non-pregnant adults.

Medicare's Bundled Payments For Care Improvement Initiative Maintained Quality Of Care For Vulnerable Patients

The Bundled Payments for Care Improvement (BPCI) initiative established four models to test whether linking payments for an episode of care could reduce Medicare payments while maintaining or improving quality. Evaluations concluded that model 2, the largest, generally lowered payments without reducing quality for the average beneficiary, but these global results could mask adverse findings among vulnerable subpopulations. We analyzed changes in emergency department visits, unplanned hospital readmissions, and all-cause mortality within ninety days of hospital discharge among beneficiaries with one or more of three vulnerable characteristics-dementia, dual eligibility for Medicare and Medicaid, and recent institutional care-in 105,458 beneficiary episodes in the period October 2013-December 2016. The results for twelve types of medical and surgical BPCI episodes were evaluated relative to results in matched comparison groups. Our findings suggest that BPCI model 2 did not adversely affect care quality for beneficiaries with vulnerabilities. While this conclusion does not discourage the further development of bundled payment models, policy makers should support ongoing research to ensure that vulnerable populations are not adversely affected by these approaches.

Physician Time Burden Associated with Querying Prescription Drug Monitoring Programs

Objective

Prescription drug monitoring programs (PDMPs) enable prescribers to review patient prescription histories, and their use is mandatory in many states. We estimated the cost of physicians retrieving PDMP patient reports compared with a model where a delegate (i.e., administrative staff) retrieves reports.

Methods

We performed a cost analysis with a one-year time horizon, from the perspective of physicians' employers. We obtained specialty-specific estimates of controlled substance prescribing frequency from the National Ambulatory Medical Care Survey, 2012-2014. We defined three PDMP usage cases based on the frequency of queries: comprehensive (before every Schedule II-IV controlled substance prescription), selective (before new Schedule II-IV prescriptions and every six months for continuing medications), and minimal (before new Schedule II or III prescriptions and annually for continuing medications).

Results

The delegate model was less costly for all specialties in the comprehensive usage case and most specialties in the selective usage case, and it was similar to physician model costs in the minimal usage case. Estimated annual costs of the physician model to a large health care system (1,000 full-time equivalent physicians) were $1.6 million for comprehensive usage, $1.1 million for selective usage, and $645,313 for minimal usage. The delegate model was less costly in the comprehensive (savings of $907,283) and selective usage cases (savings of $156,216).

Conclusions

Relying on delegates vs physicians to retrieve reports is less costly in most cases. Automation and integration of PDMP data into electronic health records may reduce costs further. Physicians, health care systems, and states should collaborate to streamline access to PDMPs.

A Broader View of Quality: Choosing Wisely Recommendations From Other Specialties With High Relevance to Emergency Care

STUDY OBJECTIVE

The American College of Emergency Physicians (ACEP) joined the Choosing Wisely campaign in 2013 and has contributed 10 recommendations to reduce low-value care. Recommendations from other specialties may also identify opportunities to improve quality and patient safety in emergency care. The Choosing Wisely work group of the ACEP Quality and Patient Safety Committee seeks to identify and characterize the Choosing Wisely recommendations from other professional societies with the highest relevance to emergency care.

METHODS

In June 2016, all Choosing Wisely recommendations from other specialties were obtained from the American Board of Internal Medicine Foundation. Using a modified Delphi method, the 10 group members rated recommendations for relevance on a validated 7-point scale. Recommendations identified as highly relevant (median score=7) were rated on 3 additional characteristics: cost savings (1=large, 5=none), risk-benefit profile (1=benefit >risk, 5=risk >benefit), and actionability by emergency physicians (1=complete, 5=none). Results are presented as overall means (eg, mean of subcategory means) and subcategory means with SDs.

RESULTS

Initial review of 412 recommendations identified 49 items as highly relevant to emergency care. Eleven were redundant with ACEP recommendations, leaving 38 items from 25 professional societies. Overall means for items ranged from 1.57 to 3.1. Recommendations' scores averaged 3.2 (SD 0.6) for cost savings, 1.9 (SD 0.4) for risk-benefit, and 1.6 (SD 0.5) for actionability. The most common conditions in these recommendations were infectious diseases (14 items; 37%), head injury (4 items; 11%), and primary headache disorders (4 items; 11%). The most frequently addressed interventions were imaging studies (11 items; 29%) and antibiotics (9 items; 24%).

CONCLUSION

Thirty-eight Choosing Wisely recommendations from other specialties are highly relevant to emergency care. Imaging studies and antibiotic use are heavily represented among them.

Geographic variation in postpartum prescription opioid use: Opportunities to improve maternal safety

BACKGROUND

Obstetric delivery is among the most common in-hospital procedures experienced by reproductive-age women, yet there is little literature on patterns of postpartum opioid prescriptions after such episodes.

METHODS

We used claims data from 871,195 vaginal deliveries to 768,455 privately-insured women with an in-hospital delivery between June 2001 and July 2013 to examine the state- and census division-level proportions of women who filled an opioid prescription within four days of hospital discharge after vaginal delivery. Our primary outcome examined the proportion of women who filled an opioid prescription after uncomplicated vaginal delivery (e.g., without forceps extraction, vacuum extraction, or 3rd/4th degree perineal laceration). Secondary outcomes examined state- and census division-level variation in opioid prescription duration (proportion of prescriptions exceeding five days) and dose (proportion of prescriptions exceeding 280 morphine milligram equivalents). We also displayed national temporal trends in opioid prescribing rate and dose for uncomplicated vaginal delivery in comparison to complicated vaginal delivery.

RESULTS

Across states, we found a 7-fold variation in postpartum opioid prescription rates (7.6-53.4%), a 5-fold variation in opioid prescriptions for greater than five days' duration (5.1-25.7%), and a 19% absolute difference in opioid prescriptions for greater than 280 morphine milligram equivalents (0-19.3%) following uncomplicated vaginal delivery.

CONCLUSIONS

These wide variations in postpartum opioid prescription practices suggest opportunities to develop guidelines on postpartum opioid use, to improve prescription safety, and to reduce opioid-related harms among women in the postpartum period.

Health Policy and Shared Decision Making in Emergency Care: A Research Agenda

Although the Patient Protection and Affordable Care Act and other laws have promoted the use of shared decision making (SDM) in recent years, few specific policies have addressed the opportunities and challenges of utilizing SDM in the emergency department (ED). Policies relating to physician payment, quality measurement, and medical-legal risks each present unique challenges to adoption of SDM in the ED. This article summarizes findings from a health policy breakout session of the 2016 Academic Emergency Medicine Consensus Conference "Shared Decision Making in the Emergency Department: Development of a Policy-relevant, Patient-centered Research Agenda." The objectives were to 1) describe federal and state policies that influence utilization or assessment of SDM; 2) identify policies and policy-focused knowledge gaps that serve as barriers to adoption of ED SDM; and 3) to define a consensus-based, policy-focused research agenda to support adoption of SDM in emergency care.

Unused opioid analgesics and drug disposal following outpatient dental surgery: A randomized controlled trial

BACKGROUND

Individuals who abuse prescription opioids often use leftover pills that were prescribed for friends or family members. Dental surgery has been identified as a common source of opioid prescriptions. We measured rates of used and unused opioids after dental surgery for a pilot program to promote safe drug disposal.

METHODS

We conducted a randomized controlled trial of opioid use patterns among patients undergoing surgical tooth extraction at a university-affiliated oral surgery practice. The primary objective was to describe opioid prescribing and consumption patterns, with the number of unused opioid pills remaining on postoperative day 21 serving as the primary outcome. The secondary aim was to measure the effect of a behavioral intervention (informing patients of a pharmacy-based opioid disposal program) on the proportion of patients who disposed or reported intent to dispose of unused opioids. (NCT02814305) Results: We enrolled 79 patients, of whom 72 filled opioid prescriptions. On average, patients received 28 opioid pills and had 15 pills (54%) left over, for a total of 1010 unused pills among the cohort. The behavioral intervention was associated with a 22% absolute increase in the proportion of patients who disposed or reported intent to dispose of unused opioids (Fisher's exact p=0.11).

CONCLUSION

Fifty-four percent of opioids prescribed in this pilot study were not used. The pharmacy-based drug disposal intervention showed a robust effect size but did not achieve statistical significance. Dentists and oral surgeons could potentially reduce opioid diversion by moderately reducing the quantity of opioid analgesics prescribed after surgery.

Choosing Wisely in Emergency Medicine: A National Survey of Emergency Medicine Academic Chairs and Division Chiefs

OBJECTIVES

The Choosing Wisely campaign was launched in 2011 to promote stewardship of medical resources by encouraging patients and physicians to speak with each other regarding the appropriateness of common tests and procedures. Medical societies including the American College of Emergency Physicians (ACEP) have developed lists of potentially low-value practices for their members to address with patients. No research has described the awareness or attitudes of emergency physicians (EPs) regarding the Choosing Wisely campaign. The study objective was to assess these beliefs among leaders of academic departments of emergency medicine (EM).

METHODS

This was a Web-based survey of emergency department (ED) chairs and division chiefs at institutions with allopathic EM residency programs. The survey examined awareness of Choosing Wisely, anticipated effects of the program, and discussions of Choosing Wisely with patients and professional colleagues. Participants also identified factors they associated with the use of potentially low-value services in the ED. Questions and answer scales were refined using iterative pilot testing with EPs and health services researchers.

RESULTS

Seventy-eight percent (105/134) of invited participants responded to the survey. Eighty percent of respondents were aware of Choosing Wisely. A majority of participants anticipate the program will decrease costs of care (72% of respondents) and use of ED diagnostic imaging (69%) but will have no effect on EP salaries (94%) or medical-legal risks (65%). Only 45% of chairs have ever addressed Choosing Wisely with patients, in contrast to 88 and 82% who have discussed it with faculty and residents, respectively. Consultant-requested tests were identified by 97% of residents as a potential contributor to low-value services in the ED.

CONCLUSIONS

A substantial majority of academic EM leaders in our study were aware of Choosing Wisely, but only slightly more than half could recall any ACEP recommendations for the program. Respondents familiar with Choosing Wisely anticipated generally positive effects, but chairs reported only infrequently discussing Choosing Wisely with patients. Future research should identify potentially low-value tests requested by consultants and objectively measure the utility and cost of these tests among ED patient populations.

Prescription monitoring programs and emergency department visits involving benzodiazepine misuse: Early evidence from 11 United States metropolitan areas

BACKGROUND

Emergency department (ED) visits involving benzodiazepines have increased in the United States. Most states have created prescription monitoring programs (PMPs) to improve drug prescribing safety. To determine the association between PMP implementation and ED visits involving benzodiazepine misuse, we conducted a retrospective analysis of data from 11 metropolitan areas in the United States from 2004 to 2011.

METHODS

We estimated rates of ED visits per 100,000 residents involving benzodiazepine misuse from the Drug Abuse Warning Network dataset. Dates of PMP implementation were obtained from program administrators. We used linear regression models to assess whether PMP implementation was associated with a change in ED visits involving benzodiazepines. Models were adjusted for calendar quarter, metropolitan area, and metropolitan area-specific linear time trends.

RESULTS

Rates of ED visits involving benzodiazepine misuse increased in all metropolitan areas during the study period. PMP implementation was not associated with a change in ED visits (mean difference: 0.9 [95% CI: -0.09 to 1.9] visits per 100,000 population per quarter; p=0.08). When analyzed by number of years after implementation, PMPs were associated with a higher visit rate in year one (0.8 [95% CI: 0.2-1.5]; p=0.01]), but not in year two (0.3 [95% CI: -2.1-2.8]; p=0.78) or year three or later (2.1 [95% CI: -0.4-4.7]; p=0.10).

CONCLUSION

We did not find evidence that PMP implementation was associated with reductions in ED visits involving benzodiazepine misuse. Future work should identify PMP features and capabilities that improve benzodiazepine safety.

Pleth variability index and fluid responsiveness of hemodynamically stable patients after cardiothoracic surgery

BACKGROUND

Fluid responsiveness is a measure of preload dependence and is defined as an increase in cardiac output due to volume expansion. Recent publications have suggested that variation in amplitude of the pulse oximetry waveform may be predictive of fluid responsiveness. The pleth variability index (PVI) was developed as a noninvasive bedside measurement of this variation in the pulse oximetry waveform.

OBJECTIVES

To measure the discriminatory value of PVI for predicting fluid responsiveness as measured by pulmonary artery catheter thermodilution in patients after cardiothoracic surgery.

METHODS

A prospective observational study of hemodynamically stable postoperative cardiac surgery patients with pulmonary artery catheters. A fingertip sensor was used to measure PVI. Vital signs, PVI, and cardiac index were measured before, during, and after passive leg raise. Fluid responsiveness was defined by increase in cardiac index of greater than 15% during passive leg raise. The discriminatory value of PVI was assessed by using the Wilcoxon method to measure the area under the receiver operating curve.

RESULTS

In 13 months, 47 patients (24 receiving mechanical ventilation, 23 spontaneously breathing) were enrolled. Fluid responsiveness was noted in 42% of intubated patients and 48% of spontaneously breathing patients. PVI was not adequate to discriminate fluid responsiveness in intubated patients (area under curve, 0.63; P = .16) or spontaneously breathing patients (area under curve, 0.41; P = .75).

CONCLUSIONS

Among postoperative cardiac surgery patients, PVI is not reliable for predicting fluid responsiveness as measured by pulmonary artery catheter thermodilution, regardless of ventilatory status.

False-negative chest radiographs in emergency department diagnosis of pneumonia

BACKGROUND

Emergency department (ED) patients frequently undergo chest x-ray (CXR) to evaluate for pneumonia. The rate of false-negative CXR in patients with pneumonia is unclear.

OBJECTIVES

Identify patients admitted with pneumonia who were diagnosed by CT despite nondiagnostic CXR.

METHODS

Retrospective analysis of quality improvement data on adult ED patients admitted with pneumonia over 21 months. Primary outcome was percent of patients diagnosed by CT despite normal CXR. Patients were classified as CXR-diagnosed if they had CXR and no CT, or if antibiotics were ordered after CXR and before CT. CT-based diagnosis was indicated by administration of antibiotics only after CT was completed.

RESULTS

49 patients (11.4%) were diagnosed by CT (p<0.001). These patients were younger (p<0.001) and more often complained of chest pain (p<0.001).

CONCLUSIONS

Patients with pneumonia may present with normal or nondiagnostic CXR, although false negatives may be less common than previously reported.

Lung carcinoma presenting with pathologic femur fracture and false-positive pregnancy test result

β-Human chorionic gonadotropin (βhCG) assays are routinely used to test for pregnancy. However, βhCG may be elevated in conditions other than pregnancy. We describe a case of metastatic lung adenocarcinoma presenting with a pathologic femur fracture and a false-positive urine pregnancy test. Lung cancer is the most common nongestational malignancy that produces βhCG among reproductive-age women. Emergency physicians should consider this rare cause of a positive pregnancy test result in women who deny recent sexual intercourse, especially if the patient is older than 40 years, has a history of tobacco use, or presents with respiratory complaints.

The effects of sedimentation and light on recruitment and development of a temperate, subtidal, epifaunal community

Sedimentation has often been implicated as a factor in structuring epifaunal assemblages on hard substrata yet there are few studies that empirically test this relationship. This study investigated the effects of light and sedimentation conditions on the initial recruitment and subsequent development of an encrusting community at Lough Hyne, S.W. Ireland. Slate settlement panels were subjected to four different conditions of sedimentation and light. The five replicates of each treatment were photographed at approximately 6-week intervals over 13 months. Values for Brillouin diversity (HB) and number of recruits were greatest for shaded panels sheltered from sediment. Number of species was much higher on downward facing panels relative to upward facing panels, regardless of conditions of sedimentation and light. Sedimentation resulted in reduced cover for some species, such as Lithothamnion spp., whilst others, such as Anomia ephippium, were less affected by this variable. Total space occupied was significantly higher for inverted panels, possibly indicating geotaxic behaviour of some larvae. Number of species on each panel condition was more similar for sets of panels exposed for shorter periods relative to the 13-month experiment, implying that post-settlement mortality may differ between treatments.