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.

Dietary protein-fiber ratio associates with circulating levels of indoxyl sulfate and p-cresyl sulfate in chronic kidney disease patients

BACKGROUND AND AIMS

Indoxyl sulfate (IS) and p-cresyl sulfate (PCS) are uremic toxins derived solely from colonic bacterial fermentation of protein. Dietary fiber may counteract this by limiting proteolytic bacterial fermentation. However, the influence of dietary intake on the generation of IS and PCS has not been adequately explored in chronic kidney disease (CKD).

METHODS AND RESULTS

This cross-sectional study included 40 CKD participants (60% male; age 69 ± 10 years; 45% diabetic) with a mean estimated glomerular filtration rate (eGFR) of 24 ± 8 mL/min/1.73 m(2), who enrolled in a randomized controlled trial of synbiotic therapy. Total and free serum IS and PCS were measured at baseline by ultra-performance liquid chromatography. Dietary intake was measured using in-depth diet histories collected by a dietitian. Associations between each toxin, dietary fiber (total, soluble and insoluble), dietary protein (total, and amino acids: tryptophan, tyrosine and phenylalanine), and the protein-fiber index (ratio of protein to fiber) were assessed using linear regression. Dietary fiber was associated with free and total serum PCS (r = -0.42 and r = -0.44, both p < 0.01), but not IS. No significant association was observed between dietary protein and either toxin. The protein-fiber index was associated with total serum IS (r = 0.40, p = 0.012) and PCS (r = 0.43, p = 0.005), independent of eGFR, sex and diabetes.

CONCLUSION

Dietary protein-fiber index is associated with serum IS and PCS levels. Such association, beyond fiber and protein alone, highlights the importance of the interplay between these nutrients. We speculate that dietary modification towards a lower protein-fiber index may contribute to lowering IS and PCS.

Cost effectiveness analysis of a next generation risk assessment score for cardiovascular disease

OBJECTIVES

The goal of this study is to determine the cost-effectiveness of MIRISK VP, a next generation coronary heart disease risk assessment score, in correctly reclassifying and appropriately treating asymptomatic, intermediate risk patients.

STUDY DESIGN

A Markov model was employed with simulated subjects based on the Multi-Ethnic Study of Atherosclerosis (MESA). This study evaluated three treatment strategies: (i) practice at MESA enrollment, (ii) current guidelines, and (iii) MIRISK VP in MESA.

METHODS

The model assessed patient healthcare costs and outcomes, expressed in terms of life years and quality-adjusted life years (QALYs), over the lifetime of the cohort from the provider and payer perspective. A total of 50,000 hypothetical individuals were used in the model. A sensitivity analysis was conducted (based on the various input parameters) for the entire cohort and also for individuals aged 65 and older.

RESULTS

Guiding treatment with MIRISK VP leads to the highest net monetary benefits when compared to the 'Practice at MESA Enrollment' or to the 'Current Guidelines' strategies. MIRISK VP resulted in a lower mortality rate from any CHD event and a modest increase in QALY of 0.12-0.17 years compared to the other two approaches.

LIMITATIONS

This study has limitations of not comparing performance against strategies other than the FRS, the results are simulated as with all models, the model does not incorporate indirect healthcare costs, and the impact of patient or physician behaviors on outcomes were not taken into account.

CONCLUSIONS

MIRISK VP has the potential to improve patient outcomes compared to the alternative strategies. It is marginally more costly than both the 'Practice at MESA Enrollment' and the 'Current Guidelines' strategies, but it provides increased effectiveness, which leads to positive net monetary benefits over either strategy.

Clinical utility of a novel coronary heart disease risk-assessment test to further classify intermediate-risk patients

Background

Current coronary heart disease (CHD) risk assessments inadequately assess intermediate‐risk patients, leaving many undertreated and vulnerable to heart attacks. A novel CHD risk‐assessment (CHDRA) tool was developed for intermediate‐risk stratification using biomarkers and established risk factors to significantly improve CHD risk discrimination.

Hypothesis

Physicians will change their treatment plan in response to more information about a patient's CHD risk level provided by the CHDRA test.

Methods

A Web‐based survey of cardiology, internal medicine, family practice, and obstetrics/gynecology physicians (n = 206) was conducted to assess the CHDRA clinical impact. Each physician was shown 3 clinical vignettes representing community‐based cohort participants randomly selected from 8 total vignettes. For each, the physicians assessed the individual's CHD risk and selected preferred therapies based on the individual's comorbidities, physical examination, and laboratory results. The individual's CHDRA score was then provided and the physicians were queried for changes to their initial treatment plans.

Results

After obtaining the CHDRA result, 70% of the physician responses indicated a change to the patient's treatment plan. The revised lipid‐management plans agreed more often (74.6% of the time) with the current Adult Treatment Panel III guidelines than did the original plans (57.6% of the time). Most physicians (71.3%) agreed with the statement that the CHDRA result provided information that would impact their current treatment decisions.

Conclusions

The CHDRA test provided additional information to which physicians responded by more often applying appropriate therapy and actions aligned with guidelines, thus demonstrating the clinical utility of the test.

Company Profile: Aviir, Inc

Aviir, Inc. is a venture-funded biotechnology company developing and commercializing laboratory tests to provide personalized information to physicians and patients, with the goal of preventing cardiovascular disease and metabolic syndromes. Leveraging advanced research, Aviir developed and launched MIRISK VP™, a risk assessment test to better identify individuals at risk of a heart attack. Aviir also offers an extensive menu of other cardiovascular and metabolic tests through its Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory. Efforts are likewise focused on expanding genomics testing capability to address sudden cardiac death attributed to inherited cardiovascular diseases. This completes their integrated precision diagnostics approach that combines biomarker immunoassays with genomic and transcription analysis, along with core clinical chemistry to deliver a comprehensive personal health solution.

Analytical performance validation of a coronary heart disease risk assessment multi-analyte proteomic test

BACKGROUND

Coronary heart disease (CHD) remains prevalent despite efforts to improve CHD risk assessment. The authors developed a multi-analyte immunoassay-based CHD risk assessment (CHDRA) algorithm, clinically validated in a multicenter study, to improve CHDRA in intermediate risk individuals.

OBJECTIVE

Clinical laboratory validation of the CHDRA biomarker assays' analytical performance.

METHODS

Multiplexed immunoassay panels developed for the seven CHDRA assays were evaluated with donor sera in a clinical laboratory. Specificity, sensitivity, interfering substances and reproducibility of the CHDRA assays, along with the effects of pre-analytical specimen processing, were evaluated.

RESULTS

Analytical measurements of the CHDRA panel proteins (CTACK, Eotaxin, Fas Ligand, HGF, IL-16, MCP-3 and sFas) exhibited acceptable accuracy (80 - 120%), cross-reactivity (< 1%), interference (< 30% at high concentrations of bilirubin, lipids, hemoglobin and HAMA), sensitivity and reproducibility (< 20% CV across multiple runs, operators and instruments). Recoveries from donor sera subjected to typical clinical laboratory pre-analytical conditions were within 80 - 120%. The pre-analytical variables did not substantively impact the CHDRA scores.

CONCLUSIONS

The CHDRA panel analytical validation in a clinical laboratory meets or exceeds the specifications established during the clinical utility studies. Risk score reproducibility across multiple test scenarios suggests the assays are not susceptible to clinical laboratory pre-analytical and analytical variation.

The synergy of permeable pavements and geothermal heat pumps for stormwater treatment and reuse

The use of permeable pavement systems with integrated geothermal heat pumps for the treatment and recycling of urban runoff is novel and timely. This study assesses the efficiency of the combined technology for controlled indoor and uncontrolled outdoor experimental rigs. Water quality parameters such as biochemical oxygen demand, nutrients, total viable heterotrophic bacteria and total coliforms were tested before and after treatment in both rigs. The water borne bacterial community genomic deoxyribonucleic acid (DNA) was analyzed by polymerase chain reaction (PCR) amplification followed by denaturing gradient gel electrophoresis (DGGE) and was further confirmed by DNA sequencing techniques. Despite the relatively high temperatures in the indirectly heated sub-base of the pavement, potentially pathogenic organisms such as Salmonella spp., Escherichia coli, faecal Streptococci and Legionella were not detected. Moreover, mean removal rates of 99% for biochemical oxygen demand, 97% for ammonia-nitrogen and 95% for orthophosphate-phosphates were recorded. This research also supports decision-makers in assessing public health risks based on qualitative molecular microbiological data associated with the recycling of treated urban runoff.

Relative adrenal insufficiency in etomidate-naïve patients with septic shock

A recent study reported that 77% of patients with septic shock had relative adrenal insufficiency. However, all patients were mechanically ventilated and received high-dose inotropes. In addition, at least 24% had prior exposure to etomidate, a drug known to suppress adrenal function. We studied the incidence of relative adrenal insufficiency in etomidate-naïve patients with septic shock by analysing the adrenal response to high-dose short synacthen test in 113 consecutive patients from three university-affiliated intensive care units in Australia. Patients were allocated to three groups according to severity of illness and inclusion criteria of the trial of low dose hydrocortisone supplementation using information from patient records. Of the 113 patients, 98 had septic shock (Group A). The incidence of relative adrenal insufficiency in this subpopulation was 24.5%. Eighty-one per cent of patients with septic shock were mechanically ventilated (Group B). In this group, the incidence of relative adrenal insufficiency was 27.8%. Only 38 of the 98 patients with septic shock (39%) fulfilled inclusion criteria for the steroid supplementation trial (Group C). In this group, the incidence of relative adrenal insufficiency was only 34.2%. In all groups its presence was associated with a higher mortality. We conclude that the incidence of relative adrenal insufficiency in etomidate-naive septic shock patients was lower than observed in the steroid supplementation trial. Further, in those who fulfilled inclusion criteria for the trial, the incidence of relative adrenal insufficiency was half that reported by the trial. Our observations raise concerns about the generalizability of the findings of the above trial to etomidate-naïve patients.

A comparison of two citrate anticoagulation regimens for continuous veno-venous hemofiltration

AIMS

To assess the safety and efficacy of two different commercial citrate containing pre-filter replacement fluids during continuous veno-venous hemofiltration (CVVH) in patients with frequent filter clotting.

SETTING

Four intensive care units.

PATIENTS

Sixty-three critically ill patients with acute renal failure (ARF).

DESIGN

Prospective observational study.

METHODS

We used a commercial citrate fluid (citrate: 11 mmol/L -fluid A) as predilution replacement for CVVH. We then changed to a new commercial citrate fluid (citrate: 14 mmol/L-fluid B) as replacement fluid and performed statistical comparisons. Replacement fluid rate was fixed at 2,000 ml/hour.

RESULTS

Filter life was 12.2 hour with fluid A compared with 17.1 hour with fluid B on average (p=0.0001). Mean post filter ionized calcium concentration was 0.52 mmol/L with fluid A compared with 0.40 mmol/L with fluid B (p<0.0001). Citrate intolerance led to cessation of treatment in one patient with fluid A and one patient with fluid B. Overall ionized calcium levels were higher (A: 1.18 vs B: 1.13 mmol/L; p<0.0001) and bicarbonate was lower (A: 22.4 vs B: 24.5 mmol/L; p<0.0001) during treatment with fluid A. Alkalemia was seen in 10 patients treated with fluid A and 16 patients treated with fluid B (NS).

CONCLUSIONS

We have developed a simple approach to regional citrate anticoagulation for CVVH using a commercial citrate-containing fluid as replacement fluid. Increasing citrate concentration from 11 to 14 mmol/L increased filter life while maintaining relative safety and simplicity.

Hyperbaric oxygen therapy for acute ischaemic stroke

BACKGROUND

Most cases of stroke are caused by impairment of blood flow to the brain (ischaemia) which results in a reduction in oxygen available and subsequent cell death. It has been postulated that hyperbaric oxygen therapy (HBOT) may reduce the volume of brain that will die by greatly increasing the oxygen available, and it may further improve outcome by reducing brain swelling. Some centres are using HBOT routinely to treat stroke.

OBJECTIVES

To assess the effectiveness and safety of adjunctive HBOT in the treatment of acute ischaemic stroke.

SEARCH STRATEGY

We searched the Cochrane Stroke Group Trials Register (last searched 9 January 2004), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 3, 2004), MEDLINE (1966 to July 2004), EMBASE (1980 to July 2004), CINAHL (1982 to July 2004), and DORCTHIM (Database of Randomised Controlled Trials in Hyperbaric Medicine) (from inception to 2004). We handsearched journals and conference proceedings, searched reference lists of articles, and contacted researchers in an effort to identify additional published and unpublished studies.

SELECTION CRITERIA

We included all randomised controlled trials that compared the effect of adjunctive HBOT with no HBOT (no treatment or sham).

DATA COLLECTION AND ANALYSIS

Two authors used standardised forms to extract the data independently. Each trial was assessed for internal validity with differences resolved by discussion. Data were extracted and entered into RevMan 4.2.

MAIN RESULTS

Three randomised controlled trials (106 participants) satisfied the inclusion criteria. The methodological quality of the trials varied but was generally high. Data could be pooled for a limited number of clinically important outcomes. There were no significant differences in mortality rate at six months in those receiving HBOT compared to the control group (relative risk 0.61, 95% confidence interval (CI) 0.17 to 2.2, P value 0.45). Two of 15 scale measures of disability and functional indicated an improvement following HBOT, both at one year follow up: the mean Trouillas Disability Scale was lower with HBOT (mean difference (MD) 2.2 points reduction with HBOT, 95% CI 0.15 to 4.3, P value 0.04) and the mean Orgogozo Scale was higher (MD 27.9 points, 95% CI 4.0 to 51.8, P value 0.02). These improvements were not reflected in other trials or functional scales.

AUTHORS' CONCLUSIONS

This systematic review has not found evidence to show that HBOT improves clinical outcomes when applied during the acute presentation of ischaemic stroke. While evidence from the three randomised controlled trials is insufficient to provide clear guidelines for practice, clinical benefit does not seem likely. Further research is required to better define the role of HBOT in this condition.

HIV resistance testing in the USA – a model for the application of pharmacogenomics in the clinical setting

Although there is debate about how and when the medical community will readily adopt pharmacogenomics into clinical practice, HIV genotyping has become an integral part of AIDS patient management in the USA since 1996. Genotyping for HIV-1 drug resistance serves as a paradigm for the way pharmacogenomics is likely to be introduced into patient care. This review discusses the unique role that HIV-1 genotype testing plays in identifying resistance in patients and how that information is used to modify therapy selection and impact the progression of disease [1] . In addition, the important issues relating to reimbursement and the cost-effectiveness of genotyping are also discussed.

Screening for physical and psychological illness in the British Armed Forces: II: Barriers to screening--learning from the opinions of Service personnel

OBJECTIVE

To identify any potential barriers to the effectiveness of a military health screening programme based on the beliefs of British Service personnel.

METHODS

As part of a pilot evaluation of the suitability of a new health screening questionnaire for the British Armed Forces, 73 men and women from the three Services, of various ranks and age, underwent a semi-structured interview after completing a screening questionnaire. Participants were asked about the veracity of their answers and their views regarding a screening questionnaire. Afterwards questionnaires were sent to 4496 randomly selected personnel from the three Services, which validated the main emerging themes. A constant comparative method of analysis was used to identify and categorise all ideas presented.

RESULTS

The main barriers to health screening were lack of trust, perceived low quality of healthcare, and perceived lack of concern within the institution about work environments and home life. The central issue was 'confidence' in military health care provision. Screening was considered worthwhile, but many confided that they would not honestly answer some items in the questionnaire. Lack of trust in medical confidentiality, stigmatisation and fears that the process would jeopardise career prospects were stressed. Many Service personnel admitted to seeking medical help outside the Armed Forces.

CONCLUSIONS

Concerns raised by Service personnel may endanger the value of a screening programme and the provision of health services. Greater emphasis needs to be placed upon gaining the confidence of those targeted for health screening.

A rapid intravenous phosphate replacement protocol for critically ill patients

OBJECTIVE

There is a high incidence of hypophosphataemia in the critically ill. It is known that even moderate hypophosphataemia can produce a variety of adverse consequences. Many phosphate replacement regimens have been suggested, most are conservative and few validated in the critical care environment. We designed a study to determine the apparent volume of distribution of phosphate and quantify phosphate loss in critically ill patients following rapid phosphate infusion. With these data we sought to design a phosphate replacement protocol.

METHODS

A prospective clinical study of an infusion of 14.5 mmol of phosphate ions over 1 hour in seven patients with mild, moderate or severe hypophosphataemia was performed. Serum phosphate, total calcium, ionised calcium, urea, creatinine, urinary phosphate excretion and creatinine clearance were measured prior to phosphate administration. Urinary phosphate excretion and creatinine clearance and serum phosphate levels were followed for 24 hours.

RESULTS

The median phosphate increment was 0.65 mmol/L (0.17 - 0.85). The median initial volume of distribution was 0.45 L/kg (0.21 - 0.87). There was no reduction in ionised calcium or creatinine clearance. The renal phosphate threshold was reduced in all patients.

CONCLUSIONS

The apparent volume of distribution of phosphate in this group of critically ill patients is large. Urinary phosphate losses contributed to the development of hypophosphataemia in these patients. In this patient cohort, there were no adverse effects from phosphate infusion of 14.5 mmol/hr. A rational protocol based on the estimated volume of distribution and estimated urinary losses can be developed to achieve the rapid and sustained correction of hypophosphataemia in such patients.

State implementation of the Breast and Cervical Cancer Prevention and Treatment Act of 2000: a collaborative effort among government agencies

The National Breast and Cervical Cancer Early Detection Program (NBCCEDP),administered by the Centers for Disease Control and Prevention through grants to states, tribes, and territories, has successfully provided breast and cervical cancer screening and diagnostic services to low-income women since 1990. On October 24, 2000, Congress passed the Breast and Cervical Cancer Prevention and Treatment Act (BCCPTA) authorizing states, if they chose, to provide Medicaid coverage for treatment services for women screened under theNBCCEDP. Under BCCPTA, uninsured women younger than age 65 who are screened through the NBCCEDP and found to have breast or cervical cancer (or precancerous conditions) may gain access to Medicaid services for and during their cancer treatment. Implementation of the BCCPTA requires collaboration and coordination among many government agencies, including the Centers for Disease Control and Prevention, Centers for Medicare & Medicaid Services, state Medicaid directors, and directors of state and tribal grant programs. This article describes the implementation of the program and demonstrates to policy makers that coordinating resources among government agencies can facilitate the rapid adoption of public health programs as pathways for specific populations to gain access to publicly funded health insurance coverage.