Economic analysis of surgical outcome monitoring using control charts: the SHEWHART cluster randomised trial

IMPORTANCE

Surgical complications represent a considerable proportion of hospital expenses. Therefore, interventions that improve surgical outcomes could reduce healthcare costs.

OBJECTIVE

Evaluate the effects of implementing surgical outcome monitoring using control charts to reduce hospital bed-days within 30 days following surgery, and hospital costs reimbursed for this care by the insurer.

DESIGN

National, parallel, cluster-randomised SHEWHART trial using a difference-in-difference approach.

SETTING

40 surgical departments from distinct hospitals across France.

PARTICIPANTS

155 362 patients over the age of 18 years, who underwent hernia repair, cholecystectomy, appendectomy, bariatric, colorectal, hepatopancreatic or oesophageal and gastric surgery were included in analyses.

INTERVENTION

After the baseline assessment period (2014-2015), hospitals were randomly allocated to the intervention or control groups. In 2017-2018, the 20 hospitals assigned to the intervention were provided quarterly with control charts for monitoring their surgical outcomes (inpatient death, intensive care stay, reoperation and severe complications). At each site, pairs, consisting of one surgeon and a collaborator (surgeon, anaesthesiologist or nurse), were trained to conduct control chart team meetings, display posters in operating rooms, maintain logbooks and design improvement plans.

MAIN OUTCOMES

Number of hospital bed-days per patient within 30 days following surgery, including the index stay and any acute care readmissions related to the occurrence of major adverse events, and hospital costs reimbursed for this care per patient by the insurer.

RESULTS

Postintervention, hospital bed-days per patient within 30 days following surgery decreased at an adjusted ratio of rate ratio (RRR) of 0.97 (95% CI 0.95 to 0.98; p<0.001), corresponding to a 3.3% reduction (95% CI 2.1% to 4.6%) for intervention hospitals versus control hospitals. Hospital costs reimbursed for this care per patient by the insurer significantly decreased at an adjusted ratio of cost ratio (RCR) of 0.99 (95% CI 0.98 to 1.00; p=0.01), corresponding to a 1.3% decrease (95% CI 0.0% to 2.6%). The consumption of a total of 8910 hospital bed-days (95% CI 5611 to 12 634 bed-days) and €2 615 524 (95% CI €32 366 to €5 405 528) was avoided in the intervention hospitals postintervention.

CONCLUSIONS

Using control charts paired with indicator feedback to surgical teams was associated with significant reductions in hospital bed-days within 30 days following surgery, and hospital costs reimbursed for this care by the insurer.

TRIAL REGISTRATION NUMBER

NCT02569450.

Two-Pole Nature of the Λ(1405) Resonance from Lattice QCD

This Letter presents the first lattice QCD computation of the coupled channel πΣ-K[over ¯]N scattering amplitudes at energies near 1405 MeV. These amplitudes contain the resonance Λ(1405) with strangeness S=-1 and isospin, spin, and parity quantum numbers I(J^{P})=0(1/2^{-}). However, whether there is a single resonance or two nearby resonance poles in this region is controversial theoretically and experimentally. Using single-baryon and meson-baryon operators to extract the finite-volume stationary-state energies to obtain the scattering amplitudes at slightly unphysical quark masses corresponding to m_{π}≈200  MeV and m_{K}≈487  MeV, this study finds the amplitudes exhibit a virtual bound state below the πΣ threshold in addition to the established resonance pole just below the K[over ¯]N threshold. Several parametrizations of the two-channel K matrix are employed to fit the lattice QCD results, all of which support the two-pole picture suggested by SU(3) chiral symmetry and unitarity.

Operating room organization and surgical performance: a systematic review

BACKGROUND

Organizational factors may influence surgical outcomes, regardless of extensively studied factors such as patient preoperative risk and surgical complexity. This study was designed to explore how operating room organization determines surgical performance and to identify gaps in the literature that necessitate further investigation.

METHODS

We conducted a systematic review according to PRISMA guidelines to identify original studies in Pubmed and Scopus from January 1, 2000 to December 31, 2019. Studies evaluating the association between five determinants (team composition, stability, teamwork, work scheduling, disturbing elements) and three outcomes (operative time, patient safety, costs) were included. Methodology was assessed based on criteria such as multicentric investigation, accurate population description, and study design.

RESULTS

Out of 2625 studies, 76 met inclusion criteria. Of these, 34 (44.7%) investigated surgical team composition, 15 (19.7%) team stability, 11 (14.5%) teamwork, 9 (11.8%) scheduling, and 7 (9.2%) examined the occurrence of disturbing elements in the operating room. The participation of surgical residents appeared to impact patient outcomes. Employing specialized and stable teams in dedicated operating rooms showed improvements in outcomes. Optimization of teamwork reduced operative time, while poor teamwork increased morbidity and costs. Disturbances and communication failures in the operating room negatively affected operative time and surgical safety.

CONCLUSION

While limited, existing scientific evidence suggests that operating room staffing and environment significantly influences patient outcomes. Prioritizing further research on these organizational drivers is key to enhancing surgical performance.

Acute Care Advanced Practice Providers' Use of Telehealth During the COVID-19 Pandemic

Advanced practice registered nurses and physician assistants, collectively termed advanced practice providers (APPs), have been part of telehealth for many years. During the COVID-19 pandemic, APPs experienced the growth in roles, responsibilities, and tools used for telehealth care delivery. This article uses examples from 3 health systems to highlight the ways in which telehealth use was expanded due to the pandemic, how APP roles were altered across the United States during and after the pandemic, and implications for future practice.

Impact of COVID-19 & Response Measures on HIV-HCV Prevention Services and Social Determinants in People Who Inject Drugs in 13 Sites with Recent HIV Outbreaks in Europe, North America and Israel

HIV/HCV prevention among people who inject drugs (PWID) is of key public health importance. We aimed to assess the impact of COVID-19 and associated response measures on HIV/HCV prevention services and socio-economic status of PWID in high-HIV-risk sites. Sites with recent (2011-2019) HIV outbreaks among PWID in Europe North America and Israel, that had been previously identified, were contacted early May 2020. Out of 17 sites invited to participate, 13 accepted. Semi-structured qualitative site reports were prepared covering data from March to May 2020, analyzed/coded and confirmed with a structured questionnaire, in which all sites explicitly responded to all 103 issues reported in the qualitative reports. Opioid maintenance treatment, needle/syringe programs and antiretroviral treatment /hepatitis C treatment continued, but with important reductions and operational changes. Increases in overdoses, widespread difficulties with food and hygiene needs, disruptions in drug supply, and increased homelessness were reported. Service programs rapidly reformed long established, and politically entrenched, restrictive service delivery policies. Future epidemic control measures should include mitigation of negative side-effects on service provision and socio-economic determinants in PWID.

Continued Performance Improvement-What Practicing Surgeons Can Learn From Athletes

This Viewpoint describes how surgeons can optimize performance with methods for continuous performance improvement used by athletes.

Association of Hospital Bed Turnover With Patient Outcomes in Digestive Surgery

To determine the influence of hospital bed turnover rate (BTR) on the occurrence of complications following minor or major digestive surgery.

Background

Performance improvement in surgery aims at increasing productivity while preventing complications. It is unknown whether this relationship can be influenced by the complexity of surgery.

Methods

A nationwide retrospective cohort study was conducted, based on generalized estimating equation modeling to determine the effect of hospital BTR on surgical outcomes, adjusting for patient mix and clustering within 631 public and private French hospitals. All patients who underwent minor or major digestive surgery between January 1, 2013 and December 31, 2018 were included. Hospital BTR was defined as the annual number of stays per bed for digestive surgery and categorized into tertiles. The primary endpoint was a composite measurement of events occurring within 30 days after surgery: inpatient death, extended intensive care unit (ICU) admission, and reoperation.

Results

Rate of adverse events was 2.51% in low BTR hospitals versus 2.25% in high BTR hospitals for minor surgery, and 16.79% versus 16.83% for major surgery. Patients who underwent minor surgery in high BTR hospitals experienced lower complications (odds ratio [OR], 0.89; 95% confidence interval [CI], 0.81-0.97; P = 0.009), mortality (OR, 0.87; 95% CI, 0.78-0.98, P = 0.02), ICU admission (OR, 0.83; 95% CI, 0.70-0.99; P = 0.03), and reoperation (OR, 0.91; 95% CI, 0.85-0.97; P = 0.002) compared to those in low BTR hospitals. Such differences were not consistently observed among patients admitted for major surgery.

Conclusions

High turnover of patients in beds is beneficial for minor procedures, but questionable for major surgeries.

Diabetic lumbosacral plexopathy: an unpredictable clinical entity

PURPOSE

Diabetic plexopathy is among the most unusual and disabling complication type 2 diabetic mellitus (T2DM) causing major suffering among affected individuals. The clinical presentation includes asymmetric muscle atrophy, weakness, and pain, typically associated with sudden weight loss. In part due to its rarity, this condition can be easily missed with serious consequences including potentially fatal complications.

METHODS AND RESULTS

A single case report of a 59-year-old woman with T2DM complicated by a lumbosacral plexopathy that presented with unusual clinical signs, symptoms and metabolic changes including (i) a life-threatening cardiac arrest due to a massive saddle pulmonary embolism (PE) secondary to a lower limb deep venous thrombosis ipsilateral to the plexopathy and (ii) an unexpected partial spontaneous remission of T2DM.

CONCLUSIONS

This case highlights the need for increased awareness and improved investigation and understanding of the pathogenesis and management of diabetic plexopathy, especially in rehabilitation settings for optimizing functional outcomes from rehabilitation input. Implications for rehabilitationDiabetic lumbosacral plexopathy (DLSP) is a distinct cause of neurological impairment requiring rehabilitation with a different natural history and prognosis. Its incidence almost three times higher than that of other common inflammatory neuropathies such as Guillain-Barré.Early recognition of DLSP in order to provide interventions, assessment, and therapeutic strategies in Rehabilitation.Diabetes plexopathy should remain an important consideration in the differential diagnoses when assessing any patient with diabetes presenting with acute pain and weakness in the extremities.

Plasma Levels of Acyl-Carnitines and Carboxylic Acids Correlate With Cardiovascular and Kidney Function in Subjects With Sickle Cell Trait

Subjects with sickle cell trait (SCT) carry one copy of mutated β-globin gene at position E6V at the origin of the production of sickle hemoglobin (HbS). Indeed, individuals with SCT have both normal hemoglobin and HbS, in contrast to patients with sickle cell disease who inherited of two copies of the mutated gene. Although SCT is generally benign/asymptomatic, carriers may develop certain adverse outcomes such as renal complications, venous thromboembolism, exercise-induced rhabdomyolysis … However, little is known about whether similar metabolic pathways are affected in individuals with SCT and whether these metabolic derangements, if present, correlate to clinically relevant parameters. In this study, we performed metabolomics analysis of plasma from individuals with sickle cell trait (n = 34) compared to healthy controls (n = 30). Results indicated a significant increase in basal circulating levels of hemolysis markers, mono- (pyruvate, lactate), di- and tri-carboxylates (including all Krebs cycle intermediates), suggestive of systems-wide mitochondrial dysfunction in individuals with SCT. Elevated levels of kynurenines and indoles were observed in SCT samples, along with increases in the levels of oxidative stress markers (advanced glycation and protein-oxidation end-products, malondialdehyde, oxylipins, eicosanoids). Increases in circulating levels of acyl-carnitines and fatty acids were observed, consistent with increased membrane lipid damage in individuals with sickle cell trait. Finally, correlation analyses to clinical co-variates showed that alterations in the aforementioned pathways strongly correlated with clinical measurements of blood viscosity, renal (glomerular filtration rate, microalbuminuria, uremia) and cardiovascular function (carotid-femoral pulse wave velocity, blood pressure).

Differential impacts of trail and ultra-trail running on cytokine profiles: An observational study

BACKGROUND

Endurance running events are known to cause inflammation and result in increased cytokine production. However, the effects of ultramarathons on cytokine profiles are not well characterized.

OBJECTIVE

The aim of this study was to describe and compare the effects of a trail (40 km) race and an ultra-trail (171 km) race on leukocyte concentrations and cytokine profiles.

METHODS

The study was conducted during the Ultra-Trail du Mont Blanc® ultra-marathon running event, and included 11 runners who completed the 40 km trail run and 12 runners who completed the 171 km ultra-trail. Blood samples were taken before and after the races.

RESULTS

Leukocyte concentrations significantly increased after both races. Circulating levels of IL-6, IL-1β, MCP-1, and IFN-γ were significantly higher after the longer race compared to the shorter race. Furthermore, while both races resulted in significant increases in IL-6 and IL-8, only the longer race resulted in significant increases in MIP-1β, IL-7, IL-17a, and IL-4.

CONCLUSIONS

These results illustrate that a 171 km ultra-trail race results in greater modulations in cytokine profiles than a traditional trail race.

Oxidative stress, inflammation, blood rheology, and microcirculation in adults with sickle cell disease: Effects of hydroxyurea treatment and impact of sickle cell syndrome

Inflammation and oxidative stress play a key role in the pathophysiology of sickle cell disease (SCD). However, the potential influence of different sickle genotypes, or hydroxyurea (HU) treatment, on these factors remains poorly documented. The present study compared several plasma markers of inflammation and oxidative stress, as well as microvascular function, between patients with sickle SC disease (HbSC, n = 19) and patients with sickle cell anemia (HbSS) under hydroxyurea (HU) treatment (n = 16), or not (n = 13). Hemorheological parameters and levels of inflammatory (IL-6, IL-8, IFN-γ, MCP-1, MIP-1β, TNF-α) and oxidative stress (AOPP, MDA, MPO) markers were determined. Peripheral microcirculatory cutaneous blood flow and immediate microvascular response to local heat were evaluated using laser Doppler flowmetry. Oxidative stress and inflammation were lower in HbSC patients and HbSS patients under HU therapy compared to HbSS patients not treated with HU. Blood viscosity was higher in HbSC than in HbSS patients treated with or not with HU. Vasodilation response of the cutaneous microcirculation to heat stress was higher in HbSS patients receiving HU treatment. Our results clearly established that both sickle cell genotype and HU treatment modulate inflammation and oxidative stress.

An exploratory study of the effects of strenuous exercise on markers of coagulation activation, circulating microparticles, and inflammation in sickle cell trait

This exploratory study evaluated the effect of intense exercise on biomarkers of inflammation and coagulation activation in subjects with and without sickle cell trait (SCT). Fifteen healthy African American men (18‐35 years, 5 SCT, 10 control) completed a strenuous exercise protocol. Microparticle‐associated prothrombinase and tissue factor activities, as well as soluble VCAM, total white cell and monocyte count increased transiently in all subjects following exercise. In the SCT group, exercise resulted in increased d‐dimer, erythrocyte phosphatidylserine exposure, as well as increased circulating erythrocyte‐ and endothelial‐derived microparticle numbers. These alterations could contribute to exercise‐related complications in people with SCT.

Reflected fractional Brownian motion in one and higher dimensions

Fractional Brownian motion (FBM), a non-Markovian self-similar Gaussian stochastic process with long-ranged correlations, represents a widely applied, paradigmatic mathematical model of anomalous diffusion. We report the results of large-scale computer simulations of FBM in one, two, and three dimensions in the presence of reflecting boundaries that confine the motion to finite regions in space. Generalizing earlier results for finite and semi-infinite one-dimensional intervals, we observe that the interplay between the long-time correlations of FBM and the reflecting boundaries leads to striking deviations of the stationary probability density from the uniform density found for normal diffusion. Particles accumulate at the boundaries for superdiffusive FBM while their density is depleted at the boundaries for subdiffusion. Specifically, the probability density P develops a power-law singularity, P∼r^{κ}, as a function of the distance r from the wall. We determine the exponent κ as a function of the dimensionality, the confining geometry, and the anomalous diffusion exponent α of the FBM. We also discuss implications of our results, including an application to modeling serotonergic fiber density patterns in vertebrate brains.

Hemoglobin A1c and fructosamine correlate in a patient with sickle cell disease and diabetes on chronic transfusion therapy

In patients with sickle cell disease (SCD) and diabetes mellitus (DM), hemoglobin A_1c (HbA_1c ) is unreliable and the American Diabetes Association recommends monitoring long-term glycemia by measuring serum glucose, but use of serum fructosamine (SF), a measurement independent of red cell lifespan, has been reported. SF as a screen for DM in SCD, however, is not standardized and its relationship to serum glucose has not been validated. Further, screening for DM was not adequately addressed in the 2014 National Heart, Lung, and Blood Institute (NHLBI) guidelines for SCD management. Blood transfusions, an important treatment for some patients with SCD, can also impact HbA_1c . We present a case of a patient with SCD and cystic fibrosis-related diabetes on monthly chronic transfusions therapy (CTT) who had well-correlated "steady state" HbA_1c and SF levels over time, suggesting for the first time these markers may actually be useful when following long-term glycemic control in patients with SCD on CTT programs.

Quantifying the Effect of Location Matching on Accuracy of Multiparametric Magnetic Resonance Imaging Prior to Prostate Biopsy-A Multicentre Study

Background

Multiparametric magnetic resonance imaging (mpMRI) has shown promise to improve detection of prostate cancer over conventional methods. However, most studies do not describe whether the location of mpMRI lesions match that of cancer found at biopsy, which may lead to an overestimation of accuracy.

Objective

To quantitate the effect of mapping locations of mpMRI lesions to locations of positive biopsy cores on the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of mpMRI.

Design setting and participant

We retrospectively identified patients having mpMRI of the prostate preceding prostate biopsy at three centres from 2013 to 2016. Men with targetable lesions on imaging underwent directed biopsy in addition to systematic biopsy. We correlated locations of positive mpMRI lesions with those of positive biopsy cores, defining a match when both were in the same sector of the prostate. We defined positive mpMRI as Prostate Imaging Reporting and Data System (PI-RADS) score ≥4 and significant cancer at biopsy as grade group ≥2.

Outcome measurements and statistical analysis

Sensitivity, specificity, PPV, and NPV were calculated with and without location matching.

Results and limitations

Of 446 patients, 247 (55.4%) had positive mpMRI and 232 (52.0%) had significant cancer at biopsy. Sensitivity and NPV for detecting significant cancer with location matching (both 63.4%) were decreased compared with those without location matching (77.6% and 73.9%, respectively). Of the 85 significant cancers not detected by mpMRI, most were of grade group 2 (64.7%, 55/85).

Conclusions

We report a 10-15% decrease in sensitivity and NPV when location matching was used to detect significant prostate cancer by mpMRI. False negative mpMRI remains an issue, highlighting the continued need for biopsy and for improving the standards around imaging quality and reporting.

Patient summary

The true accuracy of multiparametric magnetic resonance imaging (mpMRI) must be determined to interpret results and better counsel patients. We mapped the location of positive mpMRI lesions to where cancer was found at biopsy and found, when compared with matching to cancer anywhere in the prostate, that the accuracy of mpMRI decreased by 10-15%.

Blood Rheology: Key Parameters, Impact on Blood Flow, Role in Sickle Cell Disease and Effects of Exercise

Blood viscosity is an important determinant of local flow characteristics, which exhibits shear thinning behavior: it decreases exponentially with increasing shear rates. Both hematocrit and plasma viscosity influence blood viscosity. The shear thinning property of blood is mainly attributed to red blood cell (RBC) rheological properties. RBC aggregation occurs at low shear rates, and increases blood viscosity and depends on both cellular (RBC aggregability) and plasma factors. Blood flow in the microcirculation is highly dependent on the ability of RBC to deform, but RBC deformability also affects blood flow in the macrocirculation since a loss of deformability causes a rise in blood viscosity. Indeed, any changes in one or several of these parameters may affect blood viscosity differently. Poiseuille's Law predicts that any increase in blood viscosity should cause a rise in vascular resistance. However, blood viscosity, through its effects on wall shear stress, is a key modulator of nitric oxide (NO) production by the endothelial NO-synthase. Indeed, any increase in blood viscosity should promote vasodilation. This is the case in healthy individuals when vascular function is intact and able to adapt to blood rheological strains. However, in sickle cell disease (SCD) vascular function is impaired. In this context, any increase in blood viscosity can promote vaso-occlusive like events. We previously showed that sickle cell patients with high blood viscosity usually have more frequent vaso-occlusive crises than those with low blood viscosity. However, while the deformability of RBC decreases during acute vaso-occlusive events in SCD, patients with the highest RBC deformability at steady-state have a higher risk of developing frequent painful vaso-occlusive crises. This paradox seems to be due to the fact that in SCD RBC with the highest deformability are also the most adherent, which would trigger vaso-occlusion. While acute, intense exercise may increase blood viscosity in healthy individuals, recent works conducted in sickle cell patients have shown that light cycling exercise did not cause dramatic changes in blood rheology. Moreover, regular physical exercise has been shown to decrease blood viscosity in sickle cell mice, which could be beneficial for adequate blood flow and tissue perfusion.

Probability density of the fractional Langevin equation with reflecting walls

We investigate anomalous diffusion processes governed by the fractional Langevin equation and confined to a finite or semi-infinite interval by reflecting potential barriers. As the random and damping forces in the fractional Langevin equation fulfill the appropriate fluctuation-dissipation relation, the probability density on a finite interval converges for long times towards the expected uniform distribution prescribed by thermal equilibrium. In contrast, on a semi-infinite interval with a reflecting wall at the origin, the probability density shows pronounced deviations from the Gaussian behavior observed for normal diffusion. If the correlations of the random force are persistent (positive), particles accumulate at the reflecting wall while antipersistent (negative) correlations lead to a depletion of particles near the wall. We compare and contrast these results with the strong accumulation and depletion effects recently observed for nonthermal fractional Brownian motion with reflecting walls, and we discuss broader implications.

Receptor for Advanced Glycation End Products Antagonism Blunts Kidney Damage in Transgenic Townes Sickle Mice

A large proportion of adult patients with sickle cell disease (SCD) develops kidney disease and is at a high risk of mortality. The contribution of advanced glycation end products and their receptor (AGE/RAGE) axis has been established in the pathogenesis of multiple kidney diseases. The aim of the present study was to determine the implication of RAGE in the development of SCD-related kidney complications in a mouse model of SCD, as this has never been investigated. 8-week-old AA (normal) and SS (homozygous SCD) Townes mice were treated with a specific RAGE antagonist (RAP) or vehicle (NaCl). After 3 weeks of treatment, red blood cell count, hematocrit, and hemoglobin levels were significantly higher in RAP-treated SS mice. Reticulocyte count and sickle cell count were reduced in RAP-SS compared to their NaCl-treated littermates. The lower NADPH oxidase activity in the kidney of RAP-treated mice compared to NaCl-treated mice suggests limited ROS production. RAP-treated SS mice had decreased NF-κB protein expression and activation as well as reduced TNF-α mRNA expression in the kidney. Glomerular area, interstitial fibrosis, tubular iron deposits, and KIM-1 protein expression were significantly reduced after RAP treatment. In conclusion, this study provides evidence supporting the pathogenic role of RAGE in kidney injuries in sickle cell mice.

Altered blood rheology and impaired pressure-induced cutaneous vasodilation in a mouse model of combined type 2 diabetes and sickle cell trait

OBJECTIVE

Type 2 diabetes (T2D)-related vascular dysfunction and hemorheological abnormalities could possibly be amplified by sickle cell trait (SCT). These alterations could potentially increase the risk of vascular complications in individuals with combined T2D and SCT. Therefore, this study used a mouse model to determine whether vascular function and blood rheology were more severely altered in combined T2D and SCT than in T2D or SCT alone.

METHODS

Townes transgenic mice with or without SCT received a 12-week high fat high sucrose or standard diet to create models of combined T2D-SCT, T2D, SCT, and controls. Pressure-induced vasodilation (PIV) and sodium nitroprusside (SNP)-mediated vasodilation in-vivo, and hemorheological parameters were measured.

RESULTS

No significant differences in blood viscosity, hematocrit, erythrocyte deformability, or PIV were observed between the control and T2D mice, or the control and SCT mice. However, blood viscosity, erythrocyte deformability, and PIV were significantly altered in the T2D-SCT mice compared to the control mice. There were no differences in SNP response between the groups.

CONCLUSIONS

Although neither T2D nor SCT alone had significant effects on blood rheology parameters or vascular function, combined T2D-SCT mice had significantly altered blood rheology and significantly impaired vascular function.

Higher Daily Physical Activity Level Is Associated with Lower RBC Aggregation in Carotid Artery Disease Patients at High Risk of Stroke

Aim: Carotid artery disease (CAD) is an atherosclerotic inflammatory disease that affects the arterial wall, specifically at points of bifurcation where blood flow is disturbed. Abnormal blood rheology could participate in the pathophysiology of ischemic cardiovascular disease. Physical activity (PA) is known to improve blood rheology in several chronic disorders. This study aims to (i) compare the hemorheological profile of CAD patients and controls and (ii) investigate the associations between daily PA and hemorheological parameters in CAD patients. Methods: Blood viscosity, red blood cell (RBC) aggregation and RBC deformability were assessed in 80 patients (15 symptomatic and 65 asymptomatic) and 14 age-matched controls. Patients' PA levels were evaluated using questionnaires. Results: Symptomatic patients showed increased blood viscosity and RBC aggregation compared to healthy controls. RBC aggregation was significantly lower in the most physically active patients compared to the least physically active ones. Blood viscosity and RBC deformability did not vary according to physical activity level. Conclusions: Our results showed greater hemorheological abnormalities (blood hyper-viscosity and hyper-aggregation of red blood cells) in the most severe CAD patients, which could exacerbate the risk of stroke in patients with stenosis. As the most physically active patients had lower RBC aggregation than those who were less physically active, it is possible that regular PA may limit hemorheological alterations in CAD patients.

Alpha-thalassaemia promotes frequent vaso-occlusive crises in children with sickle cell anaemia through haemorheological changes

BACKGROUND

Sickle cell anaemia (SCA) is a severe hereditary haemoglobinopathy characterised by haemorheological abnormalities, which play a role in the occurrence of several acute and chronic clinical complications. While β^S -haplotypes and alpha-thalassaemia modulate SCA clinical severity, their effects on blood rheology have been incompletely described. The aim of this study was to test the effects of these genetic modifiers on the haemorheological properties and clinical complication of children with SCA.

PROCEDURE

Steady-state haemorheological profile, biological parameters, β^S -haplotypes, alpha-globin status, vaso-occlusive crisis (VOC) and acute chest syndrome frequencies were analysed in 128 children (aged 5 to 18 years) with SCA.

RESULTS

Patients with alpha-thalassaemia showed increased red blood cell (RBC) deformability and aggregation compared to those without. Median VOC rate was higher in patients with homozygous alpha-thalassaemia compared to those with a normal alpha genotype. Conversely, the haemorheological profile and clinical complications were not influenced by the β^S -haplotypes in our study.

CONCLUSION

Our results demonstrate that alpha-thalassaemia is associated with higher risk for VOC events in children with SCA, which may be due in part to its effects on RBC deformability and aggregation.

Association between oxidative stress and vascular reactivity in children with sickle cell anaemia and sickle haemoglobin C disease

Oxidative stress and haemolysis-associated nitric oxide (NO) depletion plays a crucial role in the development of vasculopathy in sickle cell anaemia (SS). However it remains unknown whether oxidative stress and haemolysis levels influence vascular function in patients with sickle haemoglobin C disease (SC). Microvascular response to heat (using Laser Doppler flowmetry on finger), oxidative stress biomarkers, NO metabolites, endothelin-1 and haematological parameters were compared between patients with SS and SC. Vascular function, oxidative and nitrosative markers were also measured in healthy (AA) children. SS and SC had increased plasma advanced oxidation protein products (AOPP), malondialdehyde, plasma antioxidant activities and NO end products, compared to AA. SC had lower catalase activity compared to AA and SS. Haemolytic rate, glutathione peroxidase and nitrotyrosine concentrations were significantly increased in children with SS compared to SC and AA. SS and SC had impaired microvascular reactivity compared to AA. In SS, the plateau phase of the response to local thermal heating was negatively associated with nitrotyrosine and AOPP. No association between vascular function parameters and oxidative stress markers was observed in SC. Mild haemolysis in SC, compared to SS, may limit oxidative and nitrosative stress and could explain the better preserved microvascular function in this group.

Effect of Age on Blood Rheology in Sickle Cell Anaemia and Sickle Cell Haemoglobin C Disease: A Cross-Sectional Study

OBJECTIVES

Blood rheology plays a key role in the pathophysiology of sickle cell anaemia (SS) and sickle cell haemoglobin C disease (SC), but its evolution over the lifespan is unknown.

MATERIALS AND METHODS

Blood viscosity, red blood cell (RBC) deformability and aggregation, foetal haemoglobin (HbF) and haematocrit were measured in 114 healthy individuals (AA), 267 SS (161 children + 106 adults) and 138 SC (74 children + 64 adults) patients.

RESULTS

Our results showed that 1) RBC deformability is at its maximal value during the early years of life in SS and SC populations, mainly because HbF level is also at its peak, 2) during childhood and adulthood, hydroxycarbamide treatment, HbF level and gender modulated RBC deformability in SS patients, independently of age, 3) blood viscosity is higher in older SS and SC patients compared to younger ones and 4) haematocrit decreases as SS patients age.

CONCLUSION

The hemorheological changes detected in older patients could play a role in the progressive development of several chronic disorders in sickle cell disease, whose prevalence increases with age. Retarding these age-related haemorheological impairments, by using suitable drugs, may minimize the risks of vaso-occlusive events and chronic disorders.

FRAILTY, FOOD INSECURITY, AND NUTRITIONAL STATUS IN PEOPLE LIVING WITH HIV

BACKGROUND

Nutritional status and food insecurity are associated with frailty in the general U.S. population, yet little is known about this in the aging population of people living with HIV (PLWH).

OBJECTIVES

Given the potential importance of nutrition and the amenability to intervention, we examined the association between nutritional status, food insecurity, and frailty in PLWH.

DESIGN

Cross sectional study.

SETTING

Boston, Massachusetts, U.S.A.

PARTICIPANTS

50 PLWH, age ≥45 years, recruited from a cohort study examining risk factors for cardiovascular disease.

MEASUREMENTS

Frailty, duration of HIV, use of antiretroviral therapy, disease history, food insecurity, physical function, and physical activity were assessed by questionnaire. Dietary intake was assessed using 3-day food records. Blood was drawn for CD4+ cell count, hemoglobin, hematocrit, and lipid levels. Physical measurements included height, weight, and skinfold thickness.

RESULTS

The prevalence of frailty was 16% (n=8), 44% were pre-frail (n=22) and 40% were not frail (n=20). The number of reported difficulties with 20 activities of daily living was highest in frail (mean 10.4±3.9 SD), followed by pre-frail (6.5±4.6), and lowest in not frail participants (2.0±2.3). Seven (88%) of the frail PLWH lost weight with an average weight loss of 22.9 pounds; 6 (75%) reported unintentional weight loss, and all 6 of these met the frailty criteria for weight loss of 10 or more pounds. Nine (45%) of the not frail PLWH reported losing weight with an average weight loss of 6.2 pounds; 5 (23%) reported unintentional weight loss of <10 pounds. Frail PLWH were more likely to report being food insecure than not frail PLWH (63% vs. 10%, p=0.02), and tended to have lower energy intake than not frail PLWH.

CONCLUSION

Research is needed on targeted interventions to improve food security and activities of daily living in PLWH for both the prevention and improvement of frailty.

Does physical activity increase or decrease the risk of sickle cell disease complications?

Sickle cell disease (SCD) is the most common inherited disease in the world. Red blood cell sickling, blood cell-endothelium adhesion, blood rheology abnormalities, intravascular haemolysis, and increased oxidative stress and inflammation contribute to the pathophysiology of SCD. Because acute intense exercise may alter these pathophysiological mechanisms, physical activity is usually contra-indicated in patients with SCD. However, recent studies in sickle-cell trait carriers and in a SCD mice model show that regular physical activity could decrease oxidative stress and inflammation, limit blood rheology alterations and increase nitric oxide metabolism. Therefore, supervised habitual physical activity may benefit patients with SCD. This article reviews the literature on the effects of acute and chronic exercise on the biological responses and clinical outcomes of patients with SCD.

Implementation of Motor Imagery during Specific Aerobic Training Session in Young Tennis Players

The aim of this study was to investigate the effects of implementing motor imagery (MI) during specific tennis high intensity intermittent training (HIIT) sessions on groundstroke performance in young elite tennis players. Stroke accuracy and ball velocity of forehand and backhand drives were evaluated in ten young tennis players, immediately before and after having randomly performed two HIIT sessions. One session included MI exercises during the recovery phases, while the other included verbal encouragements for physical efforts and served as control condition. Results revealed that similar cardiac demand was observed during both sessions, while implementing MI maintained groundstroke accuracy. Embedding MI during HIIT enabled the development of physical fitness and the preservation of stroke performance. These findings bring new insight to tennis and conditioning coaches in order to fulfil the benefits of specific playing HIIT sessions, and therefore to optimise the training time.

Evaluation of inertial cavitation activity in tissue through measurement of oxidative stress

Ultrasound cavitation is an essential mechanism involved in the therapeutic local enhancement of drug delivery by ultrasound for cancer treatment. Inertial cavitation also triggers chemical reactions that generate free radicals and subsequent oxidative stress in the tissue. The aim of this study was to measure the oxidative stress induced by inertial cavitation in ex vivo tissue and to test the association between the exposure conditions and the oxidative stress. A confocal ultrasound setup was used to sonicate and create inertial cavitation in freshly excised adipose pig tissue. The ex vivo tissue samples were then processed to measure the quantity of malondialdehyde (MDA), an end-product of polyunsaturated free fatty acid oxidation. The creation of hydroxyterephthalic acid (HTA) from the reaction of terephthalic acid (TA) with free radicals in water was also quantified in vitro. Samples were sonicated for different durations using various amplitudes for the applied pressure. The results showed a minimum 2-fold increase in the amount of detected MDA in the sonicated tissue samples compared to baseline clearly suggesting the generation of free radicals by inertial cavitation. The method exhibited a moderate dependence of MDA generated upon the duration of exposure (R(2)=057,p<0.0001). The average increase in MDA concentration was approximately 2-fold, 5-fold, 6-fold, and 9-fold for exposure durations per unit of volume of 0.13, 0.17, 0.25, and 0.50s/mm(3), respectively. The results showed no statistically significant dependence on the amplitude of the pressure within the used range. Both pressure amplitude and exposure duration, however, influenced the HTA concentration (R(2)>0.95,p<0.0001). This biochemical method can be used on ex vivo tissue to detect the generation of free radicals induced by inertial cavitation. In large enough sample populations, the cavitation activity is linked to the exposure conditions of the sonication.

Guide to thoracic imaging

BACKGROUND

Thoracic imaging is commonly ordered in general practice. Guidelines exist for ordering thoracic imaging but few are specific for general practice.

OBJECTIVE

This article summarises current indications for imaging the thorax with chest X-ray and computed tomography. A simple frame-work for interpretation of the chest X-ray, suitable for trainees and practitioners providing primary care imaging in rural and remote locations, is presented.

DISCUSSION

Interpretation of thoracic imaging is best done using a systematic approach. Radiological investigation is not warranted in un-complicated upper respiratory tract infections or asthma, minor trauma or acute-on-chronic chest pain.

The abdominal compartment syndrome in patients with burn injury

INTRODUCTION

Intra-abdominal hypertension (IAH) and subsequent abdominal compartment syndrome (ACS) in burned patients is common. This sequence of events typically occurs in patients with larger burns receiving high volume fluid resuscitation.

METHODS

A review of the literature was performed. The National Library of Medicine (PUBMED) was queried for "Burn" and "Abdominal Compartment Syndrome". Twenty-nine articles were retained for study.

RESULTS

Abdominal pressure monitoring is appropriate in all patients with burns that require significant volume resuscitation (>30% total burned surface area- TBSA). Prevention of ACS in burns includes limiting fluid resuscitation, burn escharotomy, and percutaneous drainage when abdominal pressures are reaching perilous levels. Treatment includes all of the above and in addition, decompressive laparotomy when needed. However, despite decompressive laparotomy, mortality rates among burn victims with ACS remain unacceptably high.

CONCLUSION

Increasing amounts of volume delivery are associated with an increased risk of IAH. Therefore, intra-abdominal pressure should be monitored in all burn patients requiring massive fluid resuscitation. Escharotomy, paracentesis, and decompressive laparotomy may all be needed to counter the side effects of appropriate fluid resuscitation in the severely burned patient. Nevertheless, the prognosis in burn patients developing ACS is grim.

MRI brain imaging

General practitioners (GPs) are expected to be allowed to request MRI scans for adults for selected clinically appropriate indications from November 2013 as part of the expansion of Medicare-funded MRI services announced by the Federal Government in 2011. This article aims to give a brief overview of MRI brain imaging relevant to GPs, which will facilitate explanation of scan findings and management planning with their patients. Basic imaging techniques, common findings and terminology are presented using some illustrative case examples.

Intraoperative motor evoked potential monitoring - a position statement by the American Society of Neurophysiological Monitoring

The following intraoperative MEP recommendations can be made on the basis of current evidence and expert opinion: (1) Acquisition and interpretation should be done by qualified personnel. (2) The methods are sufficiently safe using appropriate precautions. (3) MEPs are an established practice option for cortical and subcortical mapping and for monitoring during surgeries risking motor injury in the brain, brainstem, spinal cord or facial nerve. (4) Intravenous anesthesia usually consisting of propofol and opioid is optimal for muscle MEPs. (5) Interpretation should consider limitations and confounding factors. (6) D-wave warning criteria consider amplitude reduction having no confounding factor explanation: >50% for intramedullary spinal cord tumor surgery, and >30-40% for peri-Rolandic surgery. (7) Muscle MEP warning criteria are tailored to the type of surgery and based on deterioration clearly exceeding variability with no confounding factor explanation. Disappearance is always a major criterion. Marked amplitude reduction, acute threshold elevation or morphology simplification could be additional minor or moderate spinal cord monitoring criteria depending on the type of surgery and the program's technique and experience. Major criteria for supratentorial, brainstem or facial nerve monitoring include >50% amplitude reduction when warranted by sufficient preceding response stability. Future advances could modify these recommendations.

Pulmonary embolism: assessment and imaging

It is estimated that there are approximately 17,000 new cases of venous thromboembolism (VTE) in Australia per year. Pulmonary embolism (PE) accounts for about 40% of these events, and is an important preventable cause of morbidity and potentially death. Clinical symptoms of PE are non-specific and can be mild (Table 1). Primary care doctors need a robust system to exclude PE as they will most often be the first port of call for patients with PE symptoms.

Radiation safety

Diagnostic radiology procedures, such as computed tomography (CT) and X-ray, are an increasing source of ionising radiation exposure to our community. Exposure to ionising radiation is associated with increased risk of malignancy, proportional to the level of exposure. Every diagnostic test using ionising radiation needs to be justified by clinical need. General practitioners need a working knowledge of radiation safety so they can adequately inform their patients of the risks and benefits of diagnostic imaging procedures.

MRI of the knee

Magnetic resonance imaging (MRI) is the gold standard in noninvasive investigation of knee pain. It has a very high negative predictive value and may assist in avoiding unnecessary knee arthroscopy; its accuracy in the diagnosis of meniscal and anterior cruciate ligament (ACL) tears is greater than 89%; it has a greater than 90% sensitivity for the detection of medial meniscal tears; and it is probably better at assessing the posterior horn than arthroscopy.

Factors predicting stomal wound closure infection rates

BACKGROUND

Stoma closure is associated with high wound infection rates. The aim of this study was to evaluate risk factors for infection rates in such wounds, with particular emphasis on assessing the importance of the stomal wound closure technique.

METHODS

A retrospective analysis of 142 patients who had undergone ileostomy or colostomy closure between 2002 and 2011 was performed. Postoperative outcome as measured by wound infection rate was recorded. Three different closure techniques were identified: primary closure (PC), primary closure with penrose drain (PCP) and purse-string circumferential wound approximation technique (PSC). Other factors such as age, sex, ASA score, type of prophylactic antibiotics used, diabetes, smoking and obesity were also analysed. All other techniques were excluded.

RESULTS

Our series consisted of 142 stomal closures (90 ileostomy and 52 colostomy closures). The patients had a median age of 63.5 years with an interquartile range of 50.1-73.2 years. The overall wound infection rate was 10.7%. PC, PCP and PSC were associated with wound infection rates of 17.9, 10.5 and 3.6%, respectively. Compared to PSC, PC and PCP were associated with significantly higher wound infection rates (p = 0.027 and p = 0.068, respectively). Obesity was a significant risk factor for wound infection (p = 0.024). Use of triple-agent antibiotics prophylactically had a protective effect on the infection rate (p = 0.012).

CONCLUSIONS

To reduce stomal wound closure infection rates, we recommend institution of closure techniques other than PC with or without a drain. Risk factors such as obesity should be addressed, and prophylactic triple antibiotics should be administered.

Standardization of a method to detect bovine sperm-bound antisperm antibodies by flow cytometry

The objectives were to standardize some methodological and analytical aspects of a direct technique to detect sperm-bound antisperm antibodies (ASAs) in bovine semen using flow cytometry, including the effects of prefixation of sperm membranes with formalin buffer solution and inclusion of dead cells in the analysis. Fourteen Angus bulls, including ASA-positive (experimentally induced ASAs) and 10 reproductively normal ASA-negative bulls, were used. Fixation of sperm membranes had no significant effect on the percentage of IgG- or IgA-bound spermatozoa detected by flow cytometry. However, including dead cells in the analysis increased the percentage of IgG-bound spermatozoa in fixed (live and dead 18.6 ± 9.7% and live 1.3 ± 0.5%; median ± SEM) and nonfixed samples (live and dead 18.8 ± 9.2%, live 1.5 ± 0.6%; P = 0.0029), as well as IgA-bound spermatozoa in fixed (live and dead 16.3 ± 6.4%, live 0.3 ± 0.5%) and nonfixed samples (live and dead 21.4 ± 4.6%, live 1.0 ± 0.5%; P = 0.0041) in semen from ASA-negative bulls. Intrasample, intra-assay, and interassay coefficients of variation (CV) were 0.8%, 4.6%, and 5.3%, respectively, for determination of sperm-bound IgG, and were 2.8%, 8.4%, and 40.3% for determination of sperm-bound IgA. Despite the high interassay CV for IgA determination, all ASA-positive bulls consistently had high percentages of IgA-bound spermatozoa. Flow cytometry correctly identified ASA-positive bulls. Confocal laser microscopy confirmed binding of ASAs to sperm heads and cytoplasmic droplets, and less frequently to midpieces and principal piece. In conclusion, although fixation was not necessary, dead cells should be excluded from the analysis, because ejaculates with a large proportion of dead cells can yield false-positive results. Flow cytometry was accurate and reliable for detection of sperm-bound IgG and IgA and discrimination between ASA-positive and ASA-negative bulls.

Survival radiology for GPs

BACKGROUND

General practitioners in regional and rural areas may be required to interpret emergency imaging of their patients without the immediate assistance of a radiologist.

OBJECTIVE

To provide a structured approach to interpretation of X-rays performed as part of routine care of common emergency presentations.

DISCUSSION

X-rays are an important diagnostic tool and should follow a complete history and examination. A structured approach and awareness of potential pitfalls will enable the primary care doctor to confidently interpret plain X-rays in emergency situations.