Pulmonary Angiopathy in Severe COVID-19: Physiologic, Imaging, and Hematologic Observations

Rationale: Clinical and epidemiologic data in coronavirus disease (COVID-19) have accrued rapidly since the outbreak, but few address the underlying pathophysiology.Objectives: To ascertain the physiologic, hematologic, and imaging basis of lung injury in severe COVID-19 pneumonia.Methods: Clinical, physiologic, and laboratory data were collated. Radiologic (computed tomography (CT) pulmonary angiography [n = 39] and dual-energy CT [DECT, n = 20]) studies were evaluated: observers quantified CT patterns (including the extent of abnormal lung and the presence and extent of dilated peripheral vessels) and perfusion defects on DECT. Coagulation status was assessed using thromboelastography.Measurements and Results: In 39 consecutive patients (male:female, 32:7; mean age, 53 ± 10 yr [range, 29-79 yr]; Black and minority ethnic, n = 25 [64%]), there was a significant vascular perfusion abnormality and increased physiologic dead space (dynamic compliance, 33.7 ± 14.7 ml/cm H2O; Murray lung injury score, 3.14 ± 0.53; mean ventilatory ratios, 2.6 ± 0.8) with evidence of hypercoagulability and fibrinolytic "shutdown". The mean CT extent (±SD) of normally aerated lung, ground-glass opacification, and dense parenchymal opacification were 23.5 ± 16.7%, 36.3 ± 24.7%, and 42.7 ± 27.1%, respectively. Dilated peripheral vessels were present in 21/33 (63.6%) patients with at least two assessable lobes (including 10/21 [47.6%] with no evidence of acute pulmonary emboli). Perfusion defects on DECT (assessable in 18/20 [90%]) were present in all patients (wedge-shaped, n = 3; mottled, n = 9; mixed pattern, n = 6).Conclusions: Physiologic, hematologic, and imaging data show not only the presence of a hypercoagulable phenotype in severe COVID-19 pneumonia but also markedly impaired pulmonary perfusion likely caused by pulmonary angiopathy and thrombosis.

Acute kidney injury: short-term and long-term effects

Acute kidney injury (AKI) is the most common cause of organ dysfunction in critically ill adults, with a single episode of AKI, regardless of stage, carrying a significant morbidity and mortality risk. Since the consensus on AKI nomenclature has been reached, data reflecting outcomes have become more apparent allowing investigation of both short- and long-term outcomes.Classically the short-term effects of AKI can be thought of as those reflecting an acute deterioration in renal function per se. However, the effects of AKI, especially with regard to distant organ function ("organ cross-talk"), are being elucidated as is the increased susceptibility to other conditions. With regards to the long-term effects, the consideration that outcome is a simple binary endpoint of dialysis or not, or survival or not, is overly simplistic, with the reality being much more complex.Also discussed are currently available treatment strategies to mitigate these adverse effects, as they have the potential to improve patient outcome and provide considerable economic health savings. Moving forward, an agreement for defining renal recovery is warranted if we are to assess and extrapolate the efficacy of novel therapies. Future research should focus on targeted therapies assessed by measure of long-term outcomes.

Benefits and risks of long-term amiodarone therapy for persistent atrial fibrillation: a meta-analysis

OBJECTIVE

To assess whether amiodarone, as part of a strategy to achieve sinus rhythm, is safe and effective compared with a placebo or rate control drug in patients with persistent atrial fibrillation (AF) of more than 30 days' duration.

METHODS

Randomized controlled trials comparing amiodarone with a placebo or rate control drug were identified through the EMBASE (January 1, 1988, to October 18, 2008), MEDLINE (January 1, 1966, to October 18, 2008), and Cochrane Controlled Trials Register (second issue 2008) databases with no language restrictions.

RESULTS

Twelve randomized controlled trials that involved a total of 5060 patients with persistent AF were considered. Amiodarone was more effective than a placebo or rate control drug in achieving sinus rhythm (21.3 vs 9.2 per 100 patient-years in sinus rhythm; relative risk [RR], 3.2; 95% confidence interval [CI], 1.9-5.5), and its use was not associated with an increased risk of long-term mortality (4.7 vs 3.9 per 100 patient-years; RR, 0.95; 95% CI, 0.8-1.1; P=.51; I2=0%). Cessation of amiodarone therapy because of intolerable adverse effects was more common compared with a placebo or rate control drug (10.7 vs 1.9 per 100 patient-years; RR, 3.0; 95% CI, 1.4-6.2; P<.001; I2=70%), but amiodarone was not associated with an increased incidence of hospitalizations (RR, 1.1; 95% CI, 0.6-2.1; P=.77; I2=90%).

CONCLUSION

Amiodarone, as part of a strategy to achieve and maintain sinus rhythm, appears to be safe and effective in patients with persistent AF. However, some patients may not tolerate the adverse effects of this agent.

Fluid-structure interaction involving large deformations: 3D simulations and applications to biological systems

Three-dimensional fluid-structure interaction (FSI) involving large deformations of flexible bodies is common in biological systems, but accurate and efficient numerical approaches for modeling such systems are still scarce. In this work, we report a successful case of combining an existing immersed-boundary flow solver with a nonlinear finite-element solid-mechanics solver specifically for three-dimensional FSI simulations. This method represents a significant enhancement from the similar methods that are previously available. Based on the Cartesian grid, the viscous incompressible flow solver can handle boundaries of large displacements with simple mesh generation. The solid-mechanics solver has separate subroutines for analyzing general three-dimensional bodies and thin-walled structures composed of frames, membranes, and plates. Both geometric nonlinearity associated with large displacements and material nonlinearity associated with large strains are incorporated in the solver. The FSI is achieved through a strong coupling and partitioned approach. We perform several validation cases, and the results may be used to expand the currently limited database of FSI benchmark study. Finally, we demonstrate the versatility of the present method by applying it to the aerodynamics of elastic wings of insects and the flow-induced vocal fold vibration.

Cerebro-costo-mandibular syndrome. A new familial developmental disorder

Three sibs with a hitherto unreported syndrome are described, the main features being mental handicap, palatal defects, micrognathia, and severe costovertebral defects, involving segmentation of most ribs and fusion of their dorsal ends to the vertebral bodies. In addition one infant had hypoplasia of an elbow together with defects of sacrum and coccyx; she and one other sib had minor dental defects. The syndrome is potentially lethal in the neonatal period; one of the sibs has survived. The inheritance is probably autosomal recessive.

Should we treat pyrexia? And how do we do it?

The concept of pyrexia as a protective physiological response to aid in host defence has been challenged with the awareness of the severe metabolic stress induced by pyrexia. The host response to pyrexia varies, however, according to the disease profile and severity and, as such, the management of pyrexia should differ; for example, temperature control is safe and effective in septic shock but remains controversial in sepsis. From the reported findings discussed in this review, treating pyrexia appears to be beneficial in septic shock, out of hospital cardiac arrest and acute brain injury.Multiple therapeutic options are available for managing pyrexia, with precise targeted temperature management now possible. Notably, the use of pharmacotherapy versus surface cooling has not been shown to be advantageous. The importance of avoiding hypothermia in any treatment strategy is not to be understated.Whilst a great deal of progress has been made regarding optimal temperature management in recent years, further studies will be needed to determine which patients would benefit the most from control of pyrexia and by which means this should be implemented. This narrative review is part of a series on the pathophysiology and management of pyrexia.

Vitamin D levels in critically ill patients with acute kidney injury: a protocol for a prospective cohort study (VID-AKI)

INTRODUCTION

Acute kidney injury (AKI) affects more than 50% of critically ill patients. The formation of calcitriol, the active vitamin D metabolite, from the main inactive circulating form, 25-hydroxyvitamin D (25(OH)D), occurs primarily in the proximal renal tubules. This results in a theoretical basis for reduction in levels of calcitriol over the course of an AKI. Vitamin D deficiency is highly prevalent in critically ill adults, and has been associated with increased rates of sepsis, longer hospital stays and increased mortality. The primary objective of this study is to perform serial measurements of 25(OH)D and calcitriol (1,25(OH)₂D), as well as parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) levels, in critically ill adult patients with and without AKI, and to determine whether patients with AKI have significantly lower vitamin D metabolite concentrations. The secondary objectives are to describe dynamic changes in vitamin D metabolites, PTH and FGF23 during critical illness; to compare vitamin D metabolite concentrations in patients with AKI with and without renal replacement therapy; and to investigate whether there is an association between vitamin D status and outcomes.

METHODS AND ANALYSIS

230 general adult intensive care patients will be recruited. The AKI arm will include 115 critically ill patients with AKI Kidney Disease Improving Global Outcome stage II or stage III. The comparison group will include 115 patients who require cardiovascular or respiratory support, but who do not have AKI. Serial measurements of vitamin D metabolites and associated hormones will be taken on prespecified days. Patients will be recruited from two large teaching Trusts in England. Data will be analysed using standard statistical methods.

ETHICS AND DISSEMINATION

Ethical approval was obtained. Upon completion, the study team will submit the study report for publication in a peer-reviewed scientific journal and for conference presentation.

TRIAL REGISTRATION NUMBER

NCT02869919; Pre-results.

The role of finite displacements in vocal fold modeling

Human vocal folds experience flow-induced vibrations during phonation. In previous computational models, the vocal fold dynamics has been treated with linear elasticity theory in which both the strain and the displacement of the tissue are assumed to be infinitesimal (referred to as model I). The effect of the nonlinear strain, or geometric nonlinearity, caused by finite displacements is yet not clear. In this work, a two-dimensional model is used to study the effect of geometric nonlinearity (referred to as model II) on the vocal fold and the airflow. The result shows that even though the deformation is under 1 mm, i.e., less than 10% of the size of the vocal fold, the geometric nonlinear effect is still significant. Specifically, model I underpredicts the gap width, the flow rate, and the impact stress on the medial surfaces as compared to model II. The study further shows that the differences are caused by the contact mechanics and, more importantly, the fluid-structure interaction that magnifies the error from the small-displacement assumption. The results suggest that using the large-displacement formulation in a computational model would be more appropriate for accurate simulations of the vocal fold dynamics.

Long-Term Follow-up of Acute Kidney Injury

In the general hospital setting, approximately 15% of inpatients sustain an episode of acute kidney injury (AKI) but in the critical care environment this can increase to over 25%. An episode of AKI increases the risk for both future chronic kidney disease and associated cardiovascular complications. Discharge of patients who have suffered a renal insult resulting in AKI should include consideration of longer-term follow-up, which may require nephrology input. This increase in health care burden and economic costs may be quantified and justifies the need to develop robust quality-improvement projects aimed at AKI prevention, identification, and improved management.

Acute Kidney Injury Biomarkers: What Do They Tell Us?

The definition of acute kidney injury (AKI) is now well established and encompasses changes in both the urine output and the serum creatinine (SCr) over time. Many studies to date have concentrated solely on the SCr criteria, as this is relatively easy to monitor, given that accurate urine output is rarely measured outside critical care areas. However, many studies have emphasised the inadequacies of SCr in highlighting potential renal injury in a timely fashion. These limitations reflect not only acute changes in creatinine metabolism in the critically ill but also the kinetics of creatinine generation that may hinder early recognition of AKI. In turn, this may prevent judicious intervention promoting the misconception that little can be done for patients with this devastating condition except treating the consequences. Such observations have led to much research focused on identifying early indicators of AKI that may enable early treatment and hopefully lead to improved outcomes. This explains in part the reasoning behind the interest in biomarkers of AKI and which may see them develop a role as part of established clinical tool(s) in both the assessment of severity of AKI and the potential to assess recovery. However, much of the effort behind biomarker research has focused on the ability of such candidate molecules to predict AKI as defined by the imperfect gold standards used currently. It may be that the presence of renal biomarkers associated with renal stress or injury in isolation dictates poor outcomes and as such may provide diagnostic certainty in their own right.

Advantages of percutaneous hollow needle technique for iliac bone harvest in alveolar cleft grafting

OBJECTIVE

To evaluate the percutaneous hollow needle technique for bone harvest to determine if morbidity from the bone donor site can be reduced significantly.

METHODS

A retrospective chart review was performed evaluating all patients undergoing alveolar bone grafting at our institution from January 1992 through December 1996. Patients who underwent additional major procedures were excluded. Group I consisted of 12 patients in whom the percutaneous technique was utilized. The patients had an average age of 11.1 years (range: 8 to 15 years). Six were male and six were female. One had a bilateral cleft. Group II consisted of 15 patients in whom the conventional open technique for iliac crest bone harvest was used. They had an average age of 13.1 years (range: 7 to 31 years). Six were male and nine were female. Two had bilateral clefts. Minimum follow-up was 6 months. We evaluated intraoperative blood loss, total postoperative analgesia requirement, and length of hospital stay based on a retrospective hospital chart review.

RESULTS

A significant difference was found between the two groups regarding intraoperative blood loss (group I: 83.3 cm3, group II: 208 cm3; p = .0015), postoperative total analgesia requirement (group I: 0.04 mg/kg, range: 0 to 0.17 mg/kg; group II: 0.34 mg/kg, range: 0.03 to 0.74 mg/kg; p = .0002), and length of hospital stay (group I: 1.0 days, group II: 2.13 days; p = .0001). There was no significant change in these results when bilateral clefts were excluded.

CONCLUSION

Iliac bone graft harvest using the percutaneous hollow needle technique results in less blood loss, decreased postoperative pain, and shorter hospital stays compared with the open technique.

Update on sepsis-associated acute kidney injury: emerging targeted therapies

Sepsis-associated acute kidney injury (SA-AKI) is an independent predictor of increased mortality and morbidity. It is essential that further advances in the treatment of sepsis should prioritize targeted therapies in SA-AKI in order to improve these bleak outcomes. As yet, a unique therapy that effectively reduces the impact of acute kidney injury has not been demonstrated. However, the emergence of novel targeted therapies, perhaps in combination, has the possibility of significantly reducing the long-term sequelae of an episode of SA-AKI. In this review, we will focus on the shared etiology of these conditions and how this is managed with targeted therapy and finally the emerging novel therapies that may play an additional role to current treatment strategies.

Benefits and risks of long-term amiodarone therapy for persistent atrial fibrillation: a meta-analysis

OBJECTIVE

To assess whether amiodarone, as part of a strategy to achieve sinus rhythm, is safe and effective compared with a placebo or rate control drug in patients with persistent atrial fibrillation (AF) of more than 30 days' duration.

METHODS

Randomized controlled trials comparing amiodarone with a placebo or rate control drug were identified through the EMBASE (January 1, 1988, to October 18, 2008), MEDLINE (January 1, 1966, to October 18, 2008), and Cochrane Controlled Trials Register (second issue 2008) databases with no language restrictions.

RESULTS

Twelve randomized controlled trials that involved a total of 5060 patients with persistent AF were considered. Amiodarone was more effective than a placebo or rate control drug in achieving sinus rhythm (21.3 vs 9.2 per 100 patient-years in sinus rhythm; relative risk [RR], 3.2; 95% confidence interval [CI], 1.9-5.5), and its use was not associated with an increased risk of long-term mortality (4.7 vs 3.9 per 100 patient-years; RR, 0.95; 95% CI, 0.8-1.1; P=.51; I2=0%). Cessation of amiodarone therapy because of intolerable adverse effects was more common compared with a placebo or rate control drug (10.7 vs 1.9 per 100 patient-years; RR, 3.0; 95% CI, 1.4-6.2; P<.001; I2=70%), but amiodarone was not associated with an increased incidence of hospitalizations (RR, 1.1; 95% CI, 0.6-2.1; P=.77; I2=90%).

CONCLUSION

Amiodarone, as part of a strategy to achieve and maintain sinus rhythm, appears to be safe and effective in patients with persistent AF. However, some patients may not tolerate the adverse effects of this agent.

Goal-directed therapy and acute kidney injury: as good as it gets?

The use of goal-directed therapy as part of an enhanced recovery programme is well established in terms of management of the modern high-risk surgical patient in order to reduce both morbidity and mortality. The mechanisms behind this improvement are debated, but a reduction in the development of post-operative complications including acute kidney injury may be relevant. A recent study examining this relationship has been reported and is discussed here.

Does the Implementation of a Quality Improvement Care Bundle Reduce the Incidence of Acute Kidney Injury in Patients Undergoing Emergency Laparotomy?

PURPOSE

Previous work has demonstrated a survival improvement following the introduction of an enhanced recovery protocol in patients undergoing emergency laparotomy (the emergency laparotomy pathway quality improvement care (ELPQuiC) bundle). Implementation of this bundle increased the use of intra-operative goal directed fluid therapy and ICU admission, both evidence-based strategies recommended to improve kidney outcomes. The aim of this study was to determine if the observed mortality benefit could be explained by a difference in the incidence of AKI pre- and post-implementation of the protocol.

METHOD

The primary outcome was the incidence of AKI in the pre- and post-ELPQuiC bundle patient population in four acute trusts in the United Kingdom. Secondary outcomes included the KDIGO stage specific incidence of AKI. Serum creatinine values were obtained retrospectively at baseline, in the post-operative period and the maximum recorded creatinine between day 1 and day 30 were obtained.

RESULTS

A total of 303 patients pre-ELPQuiC bundle and 426 patients post-ELPQuiC bundle implementation were identified across the four centres. The overall AKI incidence was 18.4% in the pre-bundle group versus 19.8% in the post bundle group p = 0.653. No significant differences were observed between the groups.

CONCLUSIONS

Despite this multi-centre cohort study demonstrating an overall survival benefit, implementation of the quality improvement care bundle did not affect the incidence of AKI.

Multistage electrophoresis system for the separation of cells, particles and solutes

It is common to operate equilibrium-based separation methods, such as distillation and extraction, as multistage unit operations, in which equilibrium is presumably achieved within each stage. Two rate-based separation processes, free electrophoresis and magnetic particle separation, have now been operated in multistage mode. Preparative free electrophoresis of particles and solutes has resisted scale-up and is confined to a narrow range of ionic compositions. Natural convection induced in electrophoresis buffers by Ohmic heating has been a strong deterrent and has led to such measures as radial electrophoresis in Couette flow, free-flow electrophoresis, low-gravity electrophoresis, density gradient electrophoresis, and reorienting density gradient electrophoresis, to name a few. The short vertical electrophoresis path exploited in the last-mentioned forms the basis for multistage electrophoresis. A thin-layer countercurrent distribution apparatus was designed and constructed so that up to 20 fractions could be collected on the basis of electrophoretic mobility by applying an electric field. The mixture to be separated starts in a bottom cavity, and successive top cavities collect fractions as separand particles or molecules are electrophoresed upward out of the bottom cavity. Mathematical models of this process were developed, and experiments were performed to verify the predictions of the models by collecting and counting particles in each cavity after fractionation.

Waist-to-Hip Ratio as Supernormal Stimuli: Effect of Contrapposto Pose and Viewing Angle

In women, the waist-to-hip ratio (WHR) is an indicator of attractiveness, health, youthfulness, and reproductive potential. In the current study, we hypothesized that viewing angle and body postures influence the attractiveness of these forms based on the view dependency of WHR stimuli (vdWHR). Using eye tracking, we quantified the number of fixations and dwell time on 3D images of a female avatar in two different poses (standing and contrapposto) from eight viewing angles incrementing in 45 degrees of rotation. A total of 68 heterosexual individuals (25 men and 43 women) participated in the study. Results showed that the contrapposto pose was perceived as more attractive than the standing pose and that lower vdWHR sides of the stimuli attracted more first fixation, total fixations, and dwell time. Overall, the results supported that WHR is view-dependent and vdWHRs lower than optimal WHRs are supernormal stimuli that may generate peak shifts in responding. Results are discussed in terms of the attractiveness of women's movements (gaits and dance) and augmented artistic presentations.