Quantum limits of position-sensitive photodiodes

The split photodiode and the lateral effect photodiode are two popular detectors for measuring beam displacement. For small displacements of a Gaussian beam, which is the case of interest here, they are often seen as equivalent and used interchangeably, giving a signal proportional to the displacement. We show theoretically and experimentally that in the limit of low technical noise, where the signal to noise ratio is dominated by the shot noise of the light, the lateral effect photodiode produces a better signal to noise ratio than the split photodiode, owing to its optimum spatial detector response. This quantum advantage can be practically exploited in spite of the intrinsic thermal noise of the lateral effect photodiode.

Pairing Project ECHO and patient navigation as an innovative approach to improving the health and wellness of cancer survivors in rural settings

PURPOSE

We conducted a 12-month pilot study of 2 complementary strategies for improving rural cancer survivorship outcomes: (1) Project ECHO, a telementoring model to increase knowledge and skills about cancer survivorship among multidisciplinary health care provider teams in rural areas and (2) patient navigation (PN) services to connect rural cancer survivors with resources for enhancing health and wellness.

METHODS

We recruited 4 CDC-funded National Comprehensive Cancer Control Program sites to implement Project ECHO and PN interventions for a defined rural population in each of their jurisdictions. Sites received ongoing technical assistance and a stipend to support implementation. We conducted a mixed-methods evaluation consisting of quantitative performance monitoring data and qualitative interviews with site staff to assess implementation.

FINDINGS

Site teams delivered 21 cancer survivorship ECHO sessions to rural providers resulting in 329 participant encounters. Almost all (93%) ECHO participants reported enhanced knowledge of cancer survivorship issues, and 80% reported intent to apply learnings to their practices. Site teams engaged 16 patient navigators who navigated 164 cancer survivors during the study period. Successful implementation required strong partnerships, clear avenues for recruitment of rural providers and cancer survivors, and activities tailored to local needs. Fostering ongoing relationships among sites through community of practice calls also enhanced implementation.

CONCLUSIONS

Sites successfully implemented a novel approach for enhancing care for cancer survivors in rural communities. Pairing Project ECHO to address structural barriers and PN to address individual factors affecting survivorship may help bridge the health equity gap experienced by cancer survivors in rural communities.

Effectiveness and Cost of Implementing Evidence-Based Interventions to Increase Colorectal Cancer Screening Among an Underserved Population in Chicago

With funding from the Centers for Disease Control and Prevention's Colorectal Cancer Control Program, The University of Chicago Center for Asian Health Equity partnered with a federally qualified health center (FQHC) to implement multiple evidence-based interventions (EBIs) in order to improve colorectal cancer (CRC) screening uptake. The purpose of this study is to determine the effectiveness and cost of implementing a provider reminder system entered manually and supplemented with patient reminders and provider assessment and feedback. The FQHC collected demographic characteristics of the FQHC and outcome data from January 2015 through December 2015 (preimplementation period) and cost from January 2016 through September 2017 (implementation period). Cost data were collected for the implementation period. We report on the demographics of the eligible population, CRC screening order, completion rates by sociodemographic characteristics, and, overall, the effectiveness and cost of implementation. From the preimplementation phase to the implementation phase, there was a 21.2 percentage point increase in CRC screens completed. The total cost of implementing EBIs was $40908.97. We estimated that an additional 283 screens were completed because of the interventions, and the implementation cost of the interventions was $144.65 per additional screen. With the interventions, CRC screening uptake in Chicago increased for all race/ethnicity and demographic backgrounds at the FQHC, particularly for patients aged 50 to 64 years and for Asian, Hispanic, and uninsured patients.

The Balance Hypothesis for the Avian Lumbosacral Organ and an Exploration of Its Morphological Variation

Birds (Aves) exhibit exceptional and diverse locomotor behaviors, including the exquisite ability to balance on two feet. How birds so precisely control their movements may be partly explained by a set of intriguing modifications in their lower spine. These modifications are collectively known as the lumbosacral organ (LSO) and are found in the fused lumbosacral vertebrae called the synsacrum. They include a set of transverse canal-like recesses in the synsacrum that align with lateral lobes of the spinal cord, as well as a dorsal groove in the spinal cord that houses an egg-shaped glycogen body. Based on compelling but primarily observational data, the most recent functional hypotheses for the LSO consider it to be a secondary balance organ, in which the transverse canals are analogous to the semicircular canals of the inner ear. If correct, this hypothesis would reshape our understanding of avian locomotion, yet the LSO has been largely overlooked in the recent literature. Here, we review the current evidence for this hypothesis and then explore a possible relationship between the LSO and balance-intensive locomotor ecologies. Our comparative morphological dataset consists of micro-computed tomography (μ-CT) scans of synsacra from ecologically diverse species. We find that birds that perch tend to have more prominent transverse canals, suggesting that the LSO is useful for balance-intensive behaviors. We then identify the crucial outstanding questions about LSO structure and function. The LSO may be a key innovation that allows independent but coordinated motion of the head and the body, and a full understanding of its function and evolution will require multiple interdisciplinary research efforts.

Commercial Low-citrate Anticoagulation Haemofiltration in High Risk Patients with Frequent Filter Clotting

This study assessed the safety and efficacy of a commercial low-citrate concentration-based pre-filter replacement fluid during continuous veno-venous haemofiltration (CVVH) in patients with frequent filter clotting and high risk of bleeding. We used a commercial low-citrate fluid as pre-dilution replacement fluid during CVVH (citrate: 11 mmol/l (33 meq/l), sodium: 140 mmol/l, chloride: 108 mmol/l and potassium: 1 mmol/l). A calcium and magnesium infusion was delivered separately by central line for the maintenance of serum ionized calcium (Cai) and total magnesium (Mg). In this prospective observational study, 30 patients, 124 filters and 1,515 treatment-hours were observed. Median filter life of citrate CVVH was 9.5 hours. Filter life in the 48 hours prior to citrate CVVH was also observed. In the patients on prior non-anticoagulant CVVH (n=14) filter life increased significantly with citrate (9.5 hours vs 5 hours; P<0.0001). In patients on prior heparin CVVH (n=15), filter life was similar with citrate (10 hours vs 8 hours; P=0.68). However, in patients with prior early/frequent filter clotting despite heparin (n=11) filter life increased significantly (10 hours vs 7 hours; P=0.038). Of 411 serum Cai measurements, none showed a Cai<0.85 mmol/l and, of 84 observations, none showed a serum Mg<0.6mmol/l. One patient with sepsis and shock needed to cease citrate CVVH because of progressive ionized hypocalcaemia and increasing anion gap. No other adverse effects were observed. In selected patients, CVVH with a commercial low-citrate concentration solution as pre-filter replacement fluid and a simultaneous calcium and magnesium infusion protocol appears generally safe. Filter life was acceptable and superior to that achieved with previous treatment.

Propofol Infusion Syndrome— Report of an Adult Fatality

This report describes a fatal case of the propofol infusion syndrome in an adult patient being sedated for a closed head injury using high doses of propofol. The features of circulatory collapse, metabolic acidosis, mild rhabdomyolysis and renal impairment are consistent with the syndrome and not readily attributable to alternative aetiologies. Potential mechanisms for the syndrome may relate to antagonism of beta-receptors, impaired myocardial oxygen utilization and a specific disruption to fatty-acid oxidation.

This is the first published Australian case of the propofol infusion syndrome in an adult and should serve as an additional case report to the existing literature highlighting this potentially fatal syndrome in adults.

Colorectal cancer screening interventions in 2 health care systems serving disadvantaged populations: Screening uptake and cost-effectiveness

BACKGROUND

The objectives of the current study were to assess changes in colorectal cancer (CRC) screening uptake and the cost-effectiveness of implementing multiple evidence-based interventions (EBIs). EBIs were implemented at 2 federally qualified health centers that participated in the Colorado Department of Public Health and Environment's Clinic Quality Improvement for Population Health initiative.

METHODS

Interventions included patient and provider reminder systems (health system 1), provider assessment and feedback (health systems 1 and 2), and numerous support activities (health systems 1 and 2). The authors evaluated health system 1 from July 2013 to June 2015 and health system 2 from July 2014 to June 2017. Evaluation measures included annual CRC screening uptake, EBIs implemented, funds received and expended by each health system to implement EBIs, and intervention costs to the Colorado Department of Public Health and Environment and health systems.

RESULTS

CRC screening uptake increased by 18 percentage points in health system 1 and 10 percentage points in health system 2. The improvements in CRC screening uptake, not including the cost of the screening tests, were obtained at an added cost ranging from $24 to $29 per person screened.

CONCLUSIONS

In both health systems, the multicomponent interventions implemented likely resulted in improvements in CRC screening. The results suggest that significant increases in CRC screening uptake can be achieved in federally qualified health centers when appropriate technical support and health system commitment are present. The cost estimates of the multicomponent interventions suggest that these interventions and support activities can be implemented in a cost-effective manner.

The effect of intensive care unit admission on smokers' attitudes and their likelihood of quitting smoking

We sought to estimate the proportion of patients admitted to a metropolitan intensive care unit (ICU) who were current smokers, and the relationships between ICU survivors who smoked and smoking cessation and/or reduction six months post-ICU discharge. We conducted a prospective cohort study at a metropolitan level III ICU in Melbourne, Victoria. One hundred consecutive patients who met the inclusion criteria were included in the study. Inclusion criteria consisted of patients who were smokers at time of ICU admission, had an ICU length of stay greater than one day, survived to ICU discharge, and provided written informed consent. A purpose-designed questionnaire which included the Fagerstrom test for nicotine dependence and evaluation of patients' attitude towards smoking cessation was completed by participants following ICU discharge and prior to hospital discharge. Participants were re-interviewed over the phone at six months post-ICU discharge. Of the 1,062 patients admitted to ICU, 253 (23%) were current smokers and 100 were enrolled. Six months post-ICU discharge, 28 (33%) of the 86 participants who were alive and contactable had quit smoking and 35 (41%) had reduced smoking. The median number of reported cigarettes smoked per day reduced by 40%. Participants who initially believed their ICU admission was smoking-related were more likely to have quit six months post-ICU discharge (odds ratio 2.98; 95% confidence interval 1.07 to 8.26; <i>P</i>=0.036). Six months post-ICU discharge, 63/86 (74%) of participants had quit or reduced their smoking. Further research into targeted smoking cessation counselling for ICU survivors is indicated.

Low-dose Citrate Continuous Veno-venous Hemofiltration (CVVH) and Acid-base Balance

Objective

To evaluate the acid-base effect of low-dose regional citrate anticoagulation (RCA) during continuous veno-venous hemofiltration (CVVH).

Design

Prospective observational study.

Setting

ICUs of tertiary public and private hospitals.

Subjects

Thirty critically ill patients with acute renal failure at risk of bleeding or with a major contraindication to heparin-CVVH and/or short filter life.

Methods

We used a commercial citrate-based fluid (11 mmol/L, sodium: 140 mmol/L, chloride: 108 mmol/L and 1 mol/L of potassium) as pre-dilution replacement fluid during CVVH. Further potassium was added according to serum potassium levels. We measured all relevant variables for acid-base analysis according to the Stewart-Figge methodology.

Results

Before treatment, study patients had a slight metabolic acidosis, which worsened over 6 hours of RCA-CVVH (pH from 7.39 to 7.38, p<0.005; bicarbonate from 23.2 to 21.6 mmol/L, p<0.0001 and base excess from −2.0 to −3.0 mEq/L, p<0.0001) due to a significant increase in SIG (from 5.8 to 6.6 mEq/L, p<0.05) and a decrease in SIDa (from 37.5 to 36.6 mEq/L, p<0.05). These acidifying effects were attenuated by hypoalbuminemia and a decrease in lactate (from 1.48 to 1.34 mmol/L, p<0.005) and did not lead to progressive acidosis. On cessation of treatment, this acidifying effect rapidly self-corrected within six hours.

Conclusions

Low dose RCA-CVVH induces a mild acidosis secondary to an increased strong ion gap and decreased SIDa which fully self-corrects at cessation of therapy. Clinicians need to be aware of these effects to correctly interpret changes in acid-base status in such patients.

Screening for physical and psychological illness in the British Armed Forces: I: The acceptability of the programme

Objectives: To assess the response to a self-administered questionnaire and attendance of a medical centre for physical and psychological health screening.

Methods: 4500 men and women from the three services were randomly selected to receive either a full or abridged screening questionnaire. The full questionnaire included the General Health Questionnaire-12 (GHQ-12) and Post-traumatic Stress Disorder (PTSD) checklist, 15 symptoms, a self-assessed health status question and three questions on alcohol behaviour (WHO Audit). The abridged questionnaire included GHQ-4, a slightly shortened PTSD checklist and five symptoms, but excluded questions on alcohol behaviour. All 'screen-positive' and a random 'screen-negative' sample were invited to attend a medical centre.

Results: 67.1% of the servicemen completed a questionnaire; slightly but significantly more the abridged than the full questionnaire (4.9%, 95% confidence interval 2.3–7.4%). Of those receiving a full or abridged questionnaire, 32% and 22.5% respectively were 'screen-positives', most of the difference (7.5%) attributable to alcohol behaviour. Less than 30% of the servicemen invited to attend a medical centre accepted the invitation, even fewer during the preparation for deployment to Iraq. Those who fulfilled the criteria for PTSD, alcohol behaviour or multi-criteria 'screen-positive' were more reluctant than controls to attend.

Conclusions: Screening for psychological illness has little support among servicemen, perhaps because they may not wish to share concerns with a military doctor. Avoidance behaviour among those with a psychological condition may also selectively reduce willingness to attend a medical centre. Screening during pre-deployment periods has even less support than at other times.

Screening for physical and psychological illness in the British Armed Forces: III: The value of a questionnaire to assist a Medical Officer to decide who needs help

Objectives: To estimate the positive and negative predictive values (PPVT and NPVT), sensitivity and specificity of a full and abridged screening questionnaire of physical and psychological health, using primary care doctors' (medical officers [MOs]) assessments as to whether the servicemen needed medical help as a gold standard.

Methods: From a tri-service random sample of those who completed a questionnaire, all 'screen-positive' and an equal random sample of 'screen-negative' were selected to attend their medical centre. MOs were aware that the screening was aimed at detecting psychological illness, but were blind as to the 'screen-positivity' of any serviceman. The MO completed a questionnaire that asked whether the patient needed medical help and whether s/he was previously aware of this need.

Results: 314 subjects were available for analysis. The PPVT was 47% (95% confidence interval [CI] 36–59%) for the full questionnaire and 48% (95% CI 36–60%) for the abridged questionnaire. Of those 'screen-positive' subjects whom the MO rated as needing help, one third had problems already known to the MO, regardless of the length of the questionnaire. The sensitivity and specificity of the full and abridge questionnaires were 43% and 74%, and 36% and 83% respectively. The PPVT did not vary greatly between health dimensions nor did selection of servicemen with very high scores.

Conclusions: The use of MOs as a gold standard is important because of their central role in initiating the management of any condition uncovered by a screening programme. Using MOs as a gold standard, the validity of the screening questionnaires for physical and psychological health in the military was mediocre.