Fully neuromorphic vision and control for autonomous drone flight.

Biological sensing and processing is asynchronous and sparse, leading to low-latency and energy-efficient perception and action. In robotics, neuromorphic hardware for event-based vision and spiking neural networks promises to exhibit similar characteristics. However, robotic implementations have been limited to basic tasks with low-dimensional sensory inputs and motor actions because of the restricted network size in current embedded neuromorphic processors and the difficulties of training spiking neural networks. Here, we present a fully neuromorphic vision-to-control pipeline for controlling a flying drone. Specifically, we trained a spiking neural network that accepts raw event-based camera data and outputs low-level control actions for performing autonomous vision-based flight. The vision part of the network, consisting of five layers and 28,800 neurons, maps incoming raw events to ego-motion estimates and was trained with self-supervised learning on real event data. The control part consists of a single decoding layer and was learned with an evolutionary algorithm in a drone simulator. Robotic experiments show a successful sim-to-real transfer of the fully learned neuromorphic pipeline. The drone could accurately control its ego-motion, allowing for hovering, landing, and maneuvering sideways-even while yawing at the same time. The neuromorphic pipeline runs on board on Intel's Loihi neuromorphic processor with an execution frequency of 200 hertz, consuming 0.94 watt of idle power and a mere additional 7 to 12 milliwatts when running the network. These results illustrate the potential of neuromorphic sensing and processing for enabling insect-sized intelligent robots.

DCD donor hemodynamics as predictor of outcome after kidney transplantation.

Insufficient hemodynamics during agonal phase-ie, the period between withdrawal of life-sustaining treatment and circulatory arrest-in Maastricht category III circulatory-death donors (DCD) potentially exacerbate ischemia/reperfusion injury. We included 409 Dutch adult recipients of DCD donor kidneys transplanted between 2006 and 2014. Peripheral oxygen saturation (SpO2-with pulse oximetry at the fingertip) and systolic blood pressure (SBP-with arterial catheter) were measured during agonal phase, and were dichotomized into minutes of SpO2 > 60% or SpO2 < 60%, and minutes of SBP > 80 mmHg or SBP < 80 mmHg. Outcome measures were and primary non-function (PNF), delayed graft function (DGF), and three-year graft survival. Primary non-function (PNF) rate was 6.6%, delayed graft function (DGF) rate was 67%, and graft survival at three years was 76%. Longer periods of agonal phase (median 16 min [IQR 11-23]) contributed significantly to an increased risk of DGF (P = .012), but not to PNF (P = .071) and graft failure (P = .528). Multiple logistic regression analysis showed that an increase from 7 to 20 minutes in period of SBP < 80 mmHg was associated with 2.19 times the odds (95% CI 1.08-4.46, P = .030) for DGF. In conclusion, duration of agonal phase is associated with early transplant outcome. SBP < 80 mmHg during agonal phase shows a better discrimination for transplant outcome than SpO2 < 60% does.

Value of 18F-FDG PET/CT in diagnosing chronic Q fever in patients with central vascular disease.

BACKGROUND: The aim of this study is to describe the value of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in diagnosing chronic Q fever in patients with central vascular disease and the added value of 18F-FDG PET/CT in the diagnostic combination strategy as described in the Dutch consensus guideline for diagnosing chronic Q fever. METHODS: 18F-FDG PET/CT was performed in patients with an abdominal aortic aneurysm or aorto-iliac reconstruction and chronic Q fever, diagnosed by serology and positive PCR for Coxiella burnetii DNA in blood and/or tissue (PCR-positive study group). Patients with an abdominal aortic aneurysm or aorto-iliac reconstruction without clinical and serological findings indicating Q fever infection served as a control group. Patients with a serological profile of chronic Q fever and a negative PCR in blood were included in additional analyses (PCR-negative study group). RESULTS: Thirteen patients were evaluated in the PCR-positive study group and 22 patients in the control group. 18F-FDG PET/CT indicated vascular infection in 6/13 patients in the PCR-positive study group and 2/22 patients in the control group. 18F-FDG PET/CT demonstrated a sensitivity of 46% (95% CI: 23-71%), specificity of 91% (95% CI: 71-99%), positive predictive value of 75% (95% CI:41-93%) and negative predictive value of 74% (95% CI: 55-87%). In the PCR-negative study group, 18F-FDG PET/CT was positive in 10/20 patients (50%). CONCLUSION: The combination of 18F-FDG PET/CT, as an imaging tool for identifying a focus of infection, and Q fever serology is a valid diagnostic strategy for diagnosing chronic Q fever in patients with central vascular disease.

Organ Donation After Euthanasia: A Dutch Practical Manual.

Many physicians and patients do not realize that it is legally and medically possible to donate organs after euthanasia. The combination of euthanasia and organ donation is not a common practice, often limited by the patient's underlying pathology, but nevertheless has been performed >40 times in Belgium and the Netherlands since 2005. In anticipation of patients' requests for organ donation after euthanasia and contributing to awareness of the possibility of this combination among general practitioners and medical specialists, the Maastricht University Medical Center and the Erasmus University Medical Center Rotterdam have developed a multidisciplinary practical manual in which the organizational steps regarding this combined procedure are described and explained. This practical manual lists the various criteria to fulfill and the rules and regulations the different stakeholders involved need to comply with to meet all due diligence requirements. Although an ethicist was involved in writing this paper, this report is not specifically meant to comprehensively address the ethical issues surrounding the topic. This paper is focused on the operational aspects of the protocol.

Vascular chronic Q fever: quality of life.

The aim of this study was to evaluate the quality of life in patients with vascular chronic Q fever at time of diagnosis and during follow-up. Based upon the SF-36 questionnaire, the mean physical and mental health of each patient were assessed at 3-month intervals for up to 18 months. A total of 26 patients were included in the study. At time of diagnosis, the mean physical health and mental health score was 50·6 [95% confidence interval (CI) 46·7-54·4] and 44·6 (95% CI 41·6-47·5), respectively. During treatment, the mean physical health score declined significantly by 1·7 points each 3 months (P < 0·001) to 40·8 (95% CI 34·4-45·1). The mean mental health score significantly and steadily increased towards 51·2 (95% CI 46·9-54·3) during follow-up (P = 0·026). A total of 23% of patients were cured after 18 months of follow-up. In conclusion, quality of life at time of diagnosis for patients with vascular chronic Q fever is lower compared to a similar group of patients, matched for age and gender, with an aortic abdominal aneurysmal disease, and physical health decreases further after starting treatment. Considering the low percentage of cure, the current treatment of vascular chronic Q fever patients may require a separate strategy from that of endocarditis in order to increase survival.

Serological follow-up in patients with aorto-iliac disease and evidence of Q fever infection.

The aim of this study was to provide data on the risk of developing chronic Q fever in patients with aorto-iliac disease and evidence of previous Q fever infection. Patients with an aortic and/or iliac aneurysm or aorto-iliac reconstruction (aorto-iliac disease) and evidence of previous Q fever infection were included. The presence of phase I and II Coxiella burnetii IgG antibodies was assessed periodically using immunofluorescence assay. A total of 111 patients with aorto-iliac disease were divided into three groups, based upon the serological profile [mean follow-up: 16 ± 9 months (mean ± standard deviation)]. Group 1 consisted of 30 patients with a serological trace of C. burnetii infection (negative IgG phase I, IgG phase II titer of 1:32). Of these, 36.7% converted to serological profile matching past resolved Q fever. Group 2 included 49 patients with negative IgG phase I titer and IgG phase II titer ≥1:64. No patients developed chronic Q fever, but 14.3% converted to a positive IgG phase I titer. Group 3 consisted of 32 patients with positive IgG phase I and positive IgG phase II titers, of which 9.4% developed chronic Q fever (significantly different from group 2, p = 0.039). The IgG phase I titer increased in 28.1% of patients (from 1:64 to 1:4,096). The risk of developing chronic Q fever in patients with aorto-iliac disease and previous Q fever infection with a positive IgG phase I titer was 9.4%. The IgG phase I titer increases or becomes positive in a substantial number of patients. A standardized serological follow-up is proposed.

Screening for Coxiella burnetii seroprevalence in chronic Q fever high-risk groups reveals the magnitude of the Dutch Q fever outbreak.

The Netherlands experienced an unprecedented outbreak of Q fever between 2007 and 2010. The Jeroen Bosch Hospital (JBH) in 's-Hertogenbosch is located in the centre of the epidemic area. Based on Q fever screening programmes, seroprevalence of IgG phase II antibodies to Coxiella burnetii in the JBH catchment area was 10·7% [785 tested, 84 seropositive, 95% confidence interval (CI) 8·5-12·9]. Seroprevalence appeared not to be influenced by age, gender or area of residence. Extrapolating these data, an estimated 40 600 persons (95% CI 32 200-48 900) in the JBH catchment area have been infected by C. burnetii and are, therefore, potentially at risk for chronic Q fever. This figure by far exceeds the nationwide number of notified symptomatic acute Q fever patients and illustrates the magnitude of the Dutch Q fever outbreak. Clinicians in epidemic Q fever areas should be alert for chronic Q fever, even if no acute Q fever is reported.

Timing of cholecystectomy after mild biliary pancreatitis.

BACKGROUND: The aim of the study was to evaluate recurrent biliary events as a consequence of delay in cholecystectomy following mild biliary pancreatitis. METHODS: Between 2004 and 2007, patients with acute pancreatitis were registered prospectively in 15 Dutch hospitals. Patients with mild biliary pancreatitis were candidates for cholecystectomy. Recurrent biliary events requiring admission before and after cholecystectomy, and after endoscopic sphincterotomy (ES), were evaluated. RESULTS: Of 308 patients with mild biliary pancreatitis, 267 were candidates for cholecystectomy. Eighteen patients underwent cholecystectomy during the initial admission, leaving 249 potential candidates for cholecystectomy after discharge. Cholecystectomy was performed after a median of 6 weeks in 188 patients (75·5 per cent). Before cholecystectomy, 34 patients (13·7 per cent) were readmitted for biliary events, including 24 with recurrent biliary pancreatitis. ES was performed in 108 patients during the initial admission. Eight (7·4 per cent) of these patients suffered from biliary events after ES and before cholecystectomy, compared with 26 (18·4 per cent) of 141 patients who did not have ES (risk ratio 0·51, 95 per cent confidence interval 0·27 to 0·94; P = 0·015). Following cholecystectomy, eight (3·9 per cent) of 206 patients developed biliary events after a median of 31 weeks. Only 142 (53·2 per cent) of 267 patients were treated in accordance with the Dutch guideline, which recommends cholecystectomy or ES during the index admission or within 3 weeks thereafter. CONCLUSION: A delay in cholecystectomy after mild biliary pancreatitis carries a substantial risk of recurrent biliary events. ES reduces the risk of recurrent pancreatitis but not of other biliary events.

Leucocyte filtration of salvaged blood during cardiac surgery: effect on red blood cell function in concentrated blood compared with diluted blood.

OBJECTIVE: Leucocyte filtration of salvaged blood has been suggested to prevent patients from receiving activated leucocytes during auto-transfusion in cardiac surgery. This study examines whether leucocyte filtration of salvaged blood affects the red blood cell (RBC) function and whether there is a difference between filtration of the concentrated and diluted blood on RBC function. METHODS: Forty patients undergoing cardiac surgery with cardiopulmonary bypass were randomly divided into a group receiving leucocyte filtration of concentrated blood (High-Hct, n=20) and another group receiving leucocyte filtration of the diluted blood (Low-Hct, n=20). During operation, all the salvaged blood, as well as the residual blood, from the heart-lung machine was filtered. In the High-Hct group, blood was concentrated with a cell saver prior to filtration, whereas in the Low-Hct group, blood was filtered without concentration. RBC function was represented by RBC aggregation and deformability measured by a laser-assisted optical rotational cell analyser and by the RBC 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) contents with conventional biochemical tests. RESULTS: Leucocyte filtration of diluted blood with a low haematocrit (14+/-4%) did not affect RBC function. However, when the concentrated blood with a high haematocrit (69+/-12%) was filtered, there was a reduction of ATP content in RBCs after passing through the filter (from 1.45+/-0.57 micromol g(-1) Hb to 0.92+/-0.75 micromol g(-1) Hb, p<0.05). For patients who received the concentrated blood, their in vivo RBC function did not differ from those who received diluted blood. CONCLUSIONS: Leucocyte filtration of the diluted salvaged blood during cardiac surgery does not affect RBC function, but it tends to deplete the ATP content of RBCs as the salvaged blood has been concentrated prior to filtration.

Influence of mechanical cell salvage on red blood cell aggregation, deformability, and 2,3-diphosphoglycerate in patients undergoing cardiac surgery with cardiopulmonary bypass.

BACKGROUND: Mechanical cell salvage is increasingly used during cardiac surgery. Although this procedure is considered safe, it is unknown whether it affects the red blood cell (RBC) function, especially the RBC aggregation, deformability, and the contents of 2,3-diphosphoglycerate (2,3-DPG). This study examines the following: (1) whether the cell salvage procedure influences RBC function; and (2) whether retransfusion of the salvaged blood affects RBC function in patients. METHODS: Forty patients undergoing cardiac surgery with cardiopulmonary bypass were randomly allocated to a cell saver group (n = 20) or a control group (n = 20). In the cell saver group, the blood aspirated from the wound area and the residual blood from the heart-lung machine were processed with a continuous-flow cell saver before retransfusion. In the control group this blood was retransfused without processing. The RBC aggregation and deformability were measured with a laser-assisted optical rotational cell analyzer and 2,3,-DPG by conventional laboratory test. RESULTS: The cell saver procedure did not influence the RBC aggregation but significantly reduced the RBC deformability (p = 0.007) and the content of RBC 2,3-DPG (p = 0.032). However, in patients receiving the processed blood, their intraoperative and postoperative RBC aggregation, deformability, and 2,3-DPG content did not differ from those of the control patients. Both groups of patients had a postoperative drop of RBC function as a result of hemodilution. CONCLUSIONS: The mechanical cell salvage procedure reduces the RBC deformability and the cell 2,3-DPG content. Retransfusion of the processed blood by cell saver does not further compromise the RBC function in patients undergoing cardiac surgery with cardiopulmonary bypass.

Clinical efficacy and biocompatibility of three different leukocyte and fat removal filters during cardiac surgery.

Activated leukocytes and fat particles are associated with organ injury after a cardiac surgery. Filters are currently used to remove either leukocytes or fat particles. A novel approach with a filter that combines leukocyte and fat removal might be clinically useful. As it is not known which type of filter has a good and safe performance in both leukocyte and fat removal, we measured in this study the leukocyte and fat removal properties and the biocompatibility of three different filters. We used six Pall RS1 (Pall, Portsmouth, England) leukocyte removal filters, six Pall LipiGuard fat removal filters, and six Fresenius Biofil 02 (Fresenius, Emmer-Compascuum, The Netherlands) leukocyte removal filters and measured the passage times of 500 and 1000 mL of residual heart-lung machine blood. We determined the circulating leukocyte and platelet counts, and total hemoglobin, triglyceride, and free fatty acid concentration after the filters. In addition, we measured free hemoglobin, plasma elastase (Merck, Darmstadt, Germany), and complement C5-9 (Quidel, San Diego, CA, U.S.A.) to assess the biocompatibility of the filters. The circulating fat particles were calculated with an automated hematology analyzer. The passage time for the blood was shortest for the Biofil filter (P = 0.02, analysis of variance). The total leukocyte counts (P = 0.04) and fat particles (P = 0.02) were higher after the LipiGuard filter. This filter also had a higher increase in free hemoglobin concentration (P = 0.03). We conclude that the leukocyte removal filters were superior to the fat removal filter both in leukocyte and fat removal.

Adjusted transfusion triggers improve transfusion practice in orthopaedic surgery.

Although blood transfusion has never been safer, there remains concern about adverse effects. We designed guidelines, the 6-8-10-Flexinorm, based on the conditions which are relevant to the decision to transfuse. To evaluate these new guidelines, we performed a case-control study in patients undergoing elective primary total hip replacement. The study consisted of two parts. In the first part, physicians were strongly encouraged to use the new guidelines; in the second part, only registration took place. During the first and second part of the study, the use of packed red cells (PRC) in Hospital A (study hospital) decreased from 1.1 +/- 1.5 to 0.6 +/- 1.2 and 0.3 +/- 0.9 units, whereas in Hospital B (control), the use of PRC remained unchanged (1 +/- 1.5, 1 +/- 1.7 and 1 +/- 2 units). In the prestudy groups, 43% of the patients in Hospital A were transfused compared to 45% in Hospital B. In the first and second part of the study, 27%, respectively, 14% of the patients in Hospital A were transfused compared to 40% in both periods in Hospital B. The new guidelines lead to a reduction in the use of allogeneic blood and a decrease in the number of patients transfused.

Blood loss in orthotopic liver transplantation: a retrospective analysis of transfusion requirements and the effects of autotransfusion of cell saver blood in 164 consecutive patients.

Liver transplantation is associated with excessive blood loss. In order to identify factors influencing blood loss and to provide a basis for a pilot study to evaluate recombinant activated factor VII as a haemostatic agent, a retrospective study was performed in 164 consecutive patients with cholestatic or noncholestatic liver disease, who underwent orthotopic liver transplantation at a single centre between 1989 and 1996. Transfusion of allogeneic and autologous (cell saver) blood was used as a measurement of blood loss. Transfusion requirements were associated with age, gender, primary disease, Child-Pugh classification, serum levels of activated partial thromboplastin time, antithrombin III, urea and creatinine, platelet number, year of transplantation, length of cold ischaemia time and autologous blood transfusion. Of these variables, Child-Pugh classification (P = 0.001), urea (P = 0.0007), year of transplantation (P = 0.002), cold ischaemia time (P = 0.01) and autologous blood transfusion (P < 0.0001) were independent predictors of transfusion requirements by multivariate analysis. Thus, blood loss and transfusion requirements depend primarily on the severity of liver disease, quality of the donor liver, experience of the transplantation team and use of autologous (cell saver) blood transfusion. These findings emphasize the need for appropriate drug therapy and a critical reappraisal of current transfusion policy.

Lessons learnt from an unsuccessful clinical trial of homoeopathy

In a randomized, double-blind study, the effects of individualized homoeopathy in patients suffering from proctocolitis were investigated. The study was controlled against conventional therapy and placebo. Individually indicated homoeopathic medicines were prescribed in the 30c, 200c or 1.000c potencies. The researches did not succeed in attracting sufficient numbers of participants to arrive at statistically significant conclusions. The total number of patients in the three combined groups was only 20, which was far below the target figure. The causes of this are discussed. Bowel habit and subjective parameters were assessed by a weekly health calendar. This calendar had not been previously validated. The conventional group scored best: eight out of ten patients completed the year of research and improved both with regard to their proctocolitis and their general well-being