Using Support Vector Machines to Detect Therapeutically Incorrect Measurements by the MiniMed CGMS®
Bondia, Jorge; Tarín, Cristina; García-Gabin, Winston; Esteve, Eduardo; Fernández-Real, José Manuel; Ricart, Wifredo; Vehí, Josep
Background Current brkuamkn. Replica Schweizer Uhren online continuous glucose monitors have limited accuracy mainly in the low range of glucose measurements. This lack of accuracy is a limiting factor in their clinical use and in the development of the so-called artificial pancreas. The ability to detect incorrect readings provided by continuous glucose monitors from raw data and other information supplied by the monitor itself is of utmost clinical importance. In this study, support vector machines (SVMs), a powerful statistical learning technique, were used to detect therapeutically incorrect measurements made by the Medtronic MiniMed CGMS®. Methods Twenty patients were monitored for three days (first day at the hospital and two days at home) using the MiniMed CGMS. After the third day, the monitor data were downloaded to the physician's computer. During the first 12 hours, the patients stayed in the hospital, and blood samples were taken every 15 minutes for two hours after meals and every 30 minutes otherwise. Plasma glucose measurements were interpolated using a cubic method for time synchronization with simultaneous MiniMed CGMS measurements every five minutes, obtaining a total of 2281 samples. A Gaussian SVM classifier trained on the monitor's electrical signal and glucose estimation was tuned and validated using multiple runs of k-fold cross-validation. The classes considered were Clarke error grid zones A+B and C+D+E. Results After ten runs of ten-fold cross-validation, an average specificity and sensitivity of 92.74% and 75.49%, respectively, were obtained (see Figure 4). The average correct rate was 91.67%. Conclusions Overall, the SVM performed well, in spite of the somewhat low sensitivity. The classifier was able to detect the time intervals when the monitor's glucose profile could not be trusted due to incorrect measurements. As a result, hypoglycemic episodes missed by the monitor were detected. PMID:19885238
Comparison of ease of use of three automated external defibrillators by untrained lay people.
Eames, P; Larsen, P D; Galletly, D C
The use of automated external defibrillators (AED) by lay people has the potential to markedly increase survival from community cardiac arrest. Wider public use of AEDs requires units that can be operated safely and effectively by people with minimal or no training. This study compares the use of three AEDs by untrained lay people regarding ease-of-use, safety, pad positioning and time to defibrillation. 24 subjects with no prior exposure to the use of AEDs were asked to perform simulated defibrillation on a manikin using three defibrillators: Zoll AEDPlus, Medtronic Physio-Control LifePak CR Plus and Philips/Laerdal HeartStart OnSite Defibrillator. Subjects' performance were videotaped and reviewed for time to defibrillate, pad positioning and safety. Subjects were asked to rate the three units in terms of ease-of-use. Average times to first shock were 74.8 s for the Physio-Control, 83.0 s for the Laerdal and 153.4 s for the Zoll defibrillator. Pad positioning was scored as correct in 23/24 Laerdal trials, 19/24 Physio-Control trials and 14/24 Zoll trials. 23 out of the 24 subjects rated the Zoll most difficult to use. All subjects safely stayed clear of the unit when required. The majority of subjects safely and effectively delivered defibrillating shocks without any prior training and within quite acceptable times. Untrained subjects find the Physio-Control and Laerdal Defibrillator easier to use than the Zoll device. Features of AED design that improved ease of use are discussed.
Endothelial retention and phenotype on carbonized cardiovascular implant surfaces.
Frendl, Christopher M; Tucker, Scott M; Khan, Nadeem A; Esch, Mandy B; Kanduru, Shrinidhi; Cao, Thong M; García, Andrés J; King, Michael R; Butcher, Jonathan T
Heart valve disease is an increasing clinical burden for which there is no effective treatment outside of prosthetic replacement. Over the last 20 years, clinicians have increasingly preferred the use of biological prosthetics to mechanical valves despite their superior durability because of the lifelong anticoagulation therapy that is required. Mechanical valve surface engineering has largely focused on being as non-thrombogenic as possible, but despite decades of iteration has had insufficient impact on the anticoagulation burden. In this study, we systematically evaluate the potential for endothelialization of the pyrolytic carbon surface used in mechanical valves. We compared adsorbed adhesion ligand type (collagen I, fibronectin, laminin, and purified adhesion domain fragments GFOGER and FN7-10) and concentration on endothelial adhesion rates and adhesion strength on Medtronic-Hall prosthetic valve surfaces. Regardless of ligand type or concentration, endothelial adhesion strengthening was insufficient for their intended ultra-high shear stress environment. We then hypothesized that microfabricated trenches would reduce shear stress to tolerable levels while maintaining endothelial access to the flow stream, thereby promoting a confluent and anticoagulant endothelial monolayer. Computational fluid dynamics simulations predicted an empirical relationship of channel width, depth, and spacing that would maintain interior surface shear stress within tolerable levels. Endothelial cells seeded to confluence in these channels retained a confluent monolayer when exposed to 600 dyn/cm(2) shear stress for 48 h regardless of applied adhesive ligand. Furthermore, sheared EC expressed a mature anti-coagulant profile, including endothelial nitric oxide synthase (eNOS), VE-cadherin, and significantly downregulated plasminogen activator inhibitor-1 (PAI-1). As a final test, channeled pyrolytic carbon surfaces with confluent EC reduced human platelet adhesion 1000-fold over
In vitro evaluation of the air separation ability of four cardiovascular manufacturer extracorporeal circuit designs.
Dickinson, Timothy A; Riley, Jeffrey B; Crowley, Jeffrey C; Zabetakis, Paul M
Neurologic impairment is a common complication of adult cardiac surgery. Cerebral gaseous microemboli (GME) detected during cardiopulmonary bypass has been associated with cognitive impairment after adult cardiac surgery. Several previous studies have shown that components comprising the extracorporeal circuit (ECC) can affect the ability of the ECC to eliminate air. The differences in the air separation ability of four manufacturer's commonly used ECCs were studied. The air-separating ability of Cobe Cardiovascular, Gish Biomedical, Medtronic, and Terumo Cardiovascular Systems Corp. ECCs were studied in vitro under clinically relevant conditions. Bolus and continuous venous air were introduced and output GME patterns by size, time, and count were measured (using an embolus detection device) and statistically analyzed. Graphic representations depicting elapsed time, GME size, and bubble count helped to visually rank the air-handling performance of the ECCs. There are significant air-handling differences between the ECCs tested. Overall, the blinded results reveal that ECC A and ECC C removed significantly (p < 0.001) more suspended GME than ECC B and ECC D. In the 50-mL venous room-air bolus and the 100 mL/min pulsed air challenges, ECC B and ECC D allowed significantly more GME to pass (p < 0.001) compared with ECC A and ECC C. For example, in a 2-hour pump run ECC C would deliver 480 potential high-intensity transient signals (HITS) compared with the 9600 from the ECC B during venous room air entrainment at 100 mL/min. There are substantial and significant air-handling differences between the ECCs from the four different manufacturers. The results from this work allow for objective characterization of ECCs air-separating ability. This additional information provides an opportunity for clinicians to potentially minimize the risks of arterial air embolization and its associated deleterious neurologic effects, while allowing clinicians to make better
Comparison between an Ascenda and a silicone catheter in intrathecal baclofen therapy in pediatric patients: analysis of complications.
Motta, Francesco; Antonello, Clara Eleonora
OBJECTIVE In this single-center study the authors investigated the complications occurring before and after the introduction of the new Ascenda intrathecal catheter (Medtronic Inc.) in pediatric patients treated with intrathecal baclofen therapy (ITB) for spasticity and/or dystonia. METHODS This was a retrospective review of 508 children who had received ITB, 416 with silicone catheters in the 13 years between September 1998 and September 2011 and 92 with Ascenda catheters in the 3 years between September 2011 and August 2014. The authors evaluated major complications such as infections, CSF leaks treated, and problems related to the catheter or pump, and they compared the 2 groups of patients who had received either a silicone catheter or an Ascenda catheter implant. RESULTS One hundred twenty patients in the silicone group (29%) and 1 patient in the Ascenda group (1.1%; p < 0.001) had a major complication. In the silicone group 23 patients (5.5%) were affected by CSF leakage and 75 patients (18%) experienced 82 catheter-related events, such as occlusion, dislodgment, disconnection, or breakage, which required catheter replacement. In the Ascenda group, only 1 patient (1.1%) was affected by CSF leakage. CONCLUSIONS To the authors' knowledge, this study is the first in the literature to compare the performance of the new Ascenda catheter, introduced in 2011, with the traditional silicone catheter for intrathecal drug infusion. In their analysis, the authors found that the Ascenda catheter can reduce major complications related to the catheter after ITB pump implantation. Further investigation is necessary to expand on and confirm their results.
Beam Profile Disturbances from Implantable Pacemakers or Implantable Cardioverter-Defibrillator Interactions
Gossman, Michael S.; Nagra, Bipinpreet; Graves-Calhoun, Alison; Wilkinson, Jeffrey
The medical community is advocating for progressive improvement in the design of implantable cardioverter-defibrillators and implantable pacemakers to accommodate elevations in dose limitation criteria. With advancement already made for magnetic resonance imaging compatibility in some, a greater need is present to inform the radiation oncologist and medical physicist regarding treatment planning beam profile changes when such devices are in the field of a therapeutic radiation beam. Treatment plan modeling was conducted to simulate effects induced by Medtronic, Inc.-manufactured devices on therapeutic radiation beams. As a continuation of grant-supported research, we show that radial and transverse open beam profiles of a medical accelerator were altered when compared with profiles resulting when implantable pacemakers and cardioverter-defibrillators are placed directly in the beam. Results are markedly different between the 2 devices in the axial plane and the sagittal planes. Vast differences are also presented for the therapeutic beams at 6-MV and 18-MV x-ray energies. Maximum changes in percentage depth dose are observed for the implantable cardioverter-defibrillator as 9.3% at 6 MV and 10.1% at 18 MV, with worst distance to agreement of isodose lines at 2.3 cm and 1.3 cm, respectively. For the implantable pacemaker, the maximum changes in percentage depth dose were observed as 10.7% at 6 MV and 6.9% at 18 MV, with worst distance to agreement of isodose lines at 2.5 cm and 1.9 cm, respectively. No differences were discernible for the defibrillation leads and the pacing lead.
Dual sensor VVIR mode pacing: is it worth it?
Sulke, N; Tan, K; Kamalvand, K; Bostock, J; Bucknall, C
Dual sensor ventricular demand rate responsive (VVIR mode) pacing was compared with single sensor rate responsive pacing to assess whether this new development should be more widely incorporated in modern pacemaker devices. A within patient randomized, double-blind crossover study involving ten patients, mean age 67.4 years (70% male), had Medtronic Legend Plus dual sensor VVIR pacemakers implanted for high grade AV block and chronic or persistent paroxysmal atrial fibrillation. Performance values were compared to 20 healthy control subjects of a similar age and gender. Patients were both subjectively and objectively assessed after 2 weeks of out-of-hospital activity in VVIR mode (minute ventilation sensing), VVIR mode (activity sensing), VVIR mode (dual sensor), and VVI mode (no rate response). All patients were assessed for subjective preference for, and objective improvement in, any pacing modality as assessed by standardized daily activity protocols and graded exercise treadmill testing. Subjective perception of exercise capacity and functional status was significantly lower in VVI mode (P < 0.05) compared to any of the VVIR modes, which did not differ. After completion of the study 70% of patients chose VVIR as their preferred mode, with 30% expressing no preference. Forty percent preferred activity sensor VVIR mode pacing, 30% preferred dual sensor VVIR mode pacing, and 70% found either dual sensor VVIR mode, minute ventilation sensor VVIR mode, or both modalities least acceptable. No patient found activity sensing VVIR mode least acceptable. Graded treadmill testing revealed significantly lower exercise tolerance during VVI mode pacing (P < 0.01) compared to the VVIR modalities, which did not differ. Overall, chronotropic response was best with dual sensor pacing during standardized daily activity protocols and during the standard car journey. The data from this study suggest that there is no marked clinical advantage obtained from the use of dual sensor
Randomized comparison of renal denervation versus intensified pharmacotherapy including spironolactone in true-resistant hypertension: six-month results from the Prague-15 study.
Rosa, Ján; Widimský, Petr; Toušek, Petr; Petrák, Ondřej; Čurila, Karol; Waldauf, Petr; Bednář, František; Zelinka, Tomáš; Holaj, Robert; Štrauch, Branislav; Šomlóová, Zuzana; Táborský, Miloš; Václavík, Jan; Kociánová, Eva; Branny, Marian; Nykl, Igor; Jiravský, Otakar; Widimský, Jiří
This prospective, randomized, open-label multicenter trial evaluated the efficacy of catheter-based renal denervation (Symplicity, Medtronic) versus intensified pharmacological treatment including spironolactone (if tolerated) in patients with true-resistant hypertension. This was confirmed by 24-hour ambulatory blood pressure monitoring after excluding secondary hypertension and confirmation of adherence to therapy by measurement of plasma antihypertensive drug levels before enrollment. One-hundred six patients were randomized to renal denervation (n=52), or intensified pharmacological treatment (n=54) with baseline systolic blood pressure of 159±17 and 155±17 mm Hg and average number of drugs 5.1 and 5.4, respectively. A significant reduction in 24-hour average systolic blood pressure after 6 months (-8.6 [95% cofidence interval: -11.8, -5.3] mm Hg; P<0.001 in renal denervation versus -8.1 [95% cofidence interval: -12.7, -3.4] mm Hg; P=0.001 in pharmacological group) was observed, which was comparable in both groups. Similarly, a significant reduction in systolic office blood pressure (-12.4 [95% cofidence interval: -17.0, -7.8] mm Hg; P<0.001 in renal denervation versus -14.3 [95% cofidence interval: -19.7, -8.9] mm Hg; P<0.001 in pharmacological group) was present. Between-group differences in change were not significant. The average number of antihypertensive drugs used after 6 months was significantly higher in the pharmacological group (+0.3 drugs; P<0.001). A significant increase in serum creatinine and a parallel decrease of creatinine clearance were observed in the pharmacological group; between-group difference were borderline significant. The 6-month results of this study confirmed the safety of renal denervation. In conclusion, renal denervation achieved reduction of blood pressure comparable with intensified pharmacotherapy.
Direct Evidence of Acetaminophen Interference with Subcutaneous Glucose Sensing in Humans: A Pilot Study
Basu, Ananda; Veettil, Sona; Dyer, Roy; Peyser, Thomas
Abstract Background: Recent advances in accuracy and reliability of continuous glucose monitoring (CGM) devices have focused renewed interest on the use of such technology for therapeutic dosing of insulin without the need for independent confirmatory blood glucose meter measurements. An important issue that remains is the susceptibility of CGM devices to erroneous readings in the presence of common pharmacologic interferences. We report on a new method of assessing CGM sensor error to pharmacologic interferences using the example of oral administration of acetaminophen. Materials and Methods: We examined the responses of several different Food and Drug Administration–approved and commercially available CGM systems (Dexcom [San Diego, CA] Seven® Plus™, Medtronic Diabetes [Northridge, CA] Guardian®, and Dexcom G4® Platinum) to oral acetaminophen in 10 healthy volunteers without diabetes. Microdialysis catheters were placed in the abdominal subcutaneous tissue. Blood and microdialysate samples were collected periodically and analyzed for glucose and acetaminophen concentrations before and after oral ingestion of 1 g of acetaminophen. We compared the response of CGM sensors with the measured acetaminophen concentrations in the blood and interstitial fluid. Results: Although plasma glucose concentrations remained constant at approximately 90 mg/dL (approximately 5 mM) throughout the study, CGM glucose measurements varied between approximately 85 to 400 mg/dL (from approximately 5 to 22 mM) due to interference from the acetaminophen. The temporal profile of CGM interference followed acetaminophen concentrations measured in interstitial fluid (ISF). Conclusions: This is the first direct measurement of ISF concentrations of putative CGM interferences with simultaneous measurements of CGM performance in the presence of the interferences. The observed interference with glucose measurements in the tested CGM devices coincided temporally with appearance of
A comparative effectiveness analysis of three continuous glucose monitors: the Navigator, G4 Platinum, and Enlite.
Damiano, Edward R; McKeon, Katherine; El-Khatib, Firas H; Zheng, Hui; Nathan, David M; Russell, Steven J
The effectiveness and safety of continuous glucose monitors (CGMs) is dependent on their accuracy and reliability. The objective of this study was to compare 3 CGMs in adult and pediatric subjects with type 1 diabetes under closed-loop blood-glucose (BG) control. Twenty-four subjects (12 adults) with type 1 diabetes each participated in one 48-hour closed-loop BG control experiment. Venous plasma glucose (PG) measurements obtained every 15 minutes (4657 values) were paired in time with corresponding CGM glucose (CGMG) measurements obtained from 3 CGMs (FreeStyle Navigator, Abbott Diabetes Care; G4 Platinum, Dexcom; Enlite, Medtronic) worn simultaneously by each subject. The Navigator and G4 Platinum (G4) had the best overall accuracy, with an aggregate mean absolute relative difference (MARD) of all paired points of 12.3 ± 12.1% and 10.8 ± 9.9%, respectively. Both had lower MARDs of all paired points than Enlite (17.9 ± 15.8%, P < .005). Very large errors (MARD > 50%) were less common with the G4 (0.5%) than with the Enlite (4.3%, P = .0001) while the number of very large errors with the Navigator (1.4%) was intermediate between the G4 and Enlite (P = .1 and P = .06, respectively). The average MARD for experiments in adolescent subjects were lower than in adult subjects for the Navigator and G4, while there was no difference for Enlite. All 3 devices had similar reliability. A comprehensive head-to-head-to-head comparison of 3 CGMs revealed marked differences in both accuracy and precision. The Navigator and G4 were found to outperform the Enlite in these areas.
Local field potential recordings in a non-human primate model of Parkinsons disease using the Activa PC + S neurostimulator
NASA Astrophysics Data System (ADS)
Connolly, Allison T.; Muralidharan, Abirami; Hendrix, Claudia; Johnson, Luke; Gupta, Rahul; Stanslaski, Scott; Denison, Tim; Baker, Kenneth B.; Vitek, Jerrold L.; Johnson, Matthew D.
Objective. Using the Medtronic Activa® PC + S system, this study investigated how passive joint manipulation, reaching behavior, and deep brain stimulation (DBS) modulate local field potential (LFP) activity in the subthalamic nucleus (STN) and globus pallidus (GP). Approach. Five non-human primates were implanted unilaterally with one or more DBS leads. LFPs were collected in montage recordings during resting state conditions and during motor tasks that facilitate the expression of parkinsonian motor signs. These recordings were made in the naïve state in one subject, in the parkinsonian state in two subjects, and in both naïve and parkinsonian states in two subjects. Main results. LFPs measured at rest were consistent over time for a given recording location and parkinsonian state in a given subject; however, LFPs were highly variable between subjects, between and within recording locations, and across parkinsonian states. LFPs in both naïve and parkinsonian states across all recorded nuclei contained a spectral peak in the beta band (10-30 Hz). Moreover, the spectral content of recorded LFPs was modulated by passive and active movement of the subjects’ limbs. LFPs recorded during a cued-reaching task displayed task-related beta desynchronization in STN and GP. The bidirectional capabilities of the Activa® PC + S also allowed for recording LFPs while delivering DBS. The therapeutic effect of STN DBS on parkinsonian rigidity outlasted stimulation for 30-60 s, but there was no correlation with beta band power. Significance. This study emphasizes (1) the variability in spontaneous LFPs amongst subjects and (2) the value of using the Activa® PC + S system to record neural data in the context of behavioral tasks that allow one to evaluate a subject’s symptomatology.
Improved spatial targeting with directionally segmented deep brain stimulation leads for treating essential tremor
NASA Astrophysics Data System (ADS)
Keane, Maureen; Deyo, Steve; Abosch, Aviva; Bajwa, Jawad A.; Johnson, Matthew D.
Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) is known to exert a therapeutic effect on postural and kinetic tremor in patients with essential tremor (ET). For DBS leads implanted near the caudal border of Vim, however, there is an increased likelihood that one will also induce paresthesia side-effects by stimulating neurons within the sensory pathway of the ventral caudal (Vc) nucleus of thalamus. The aim of this computational study was to (1) investigate the neuronal pathways modulated by therapeutic, sub-therapeutic and paresthesia-inducing DBS settings in three patients with ET and (2) determine how much better an outcome could have been achieved had these patients been implanted with a DBS lead containing directionally segmented electrodes (dDBS). Multi-compartment neuron models of the thalamocortical, cerebellothalamic and medial lemniscal pathways were first simulated in the context of patient-specific anatomies, lead placements and programming parameters from three ET patients who had been implanted with Medtronic 3389 DBS leads. The models showed that in these patients, complete suppression of tremor was associated most closely with activating an average of 62% of the cerebellothalamic afferent input into Vim (n = 10), while persistent paresthesias were associated with activating 35% of the medial lemniscal tract input into Vc thalamus (n = 12). The dDBS lead design demonstrated superior targeting of the cerebello-thalamo-cortical pathway, especially in cases of misaligned DBS leads. Given the close proximity of Vim to Vc thalamus, the models suggest that dDBS will enable clinicians to more effectively sculpt current through and around thalamus in order to achieve a more consistent therapeutic effect without inducing side-effects.
Comparative hemolysis study of clinically available centrifugal pumps.
Naito, K; Suenaga, E; Cao, Z L; Suda, H; Ueno, T; Natsuaki, M; Itoh, T
Centrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP-80 (Medtronic, BioMedicus), Sarns Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM-15 (Nikkiso), and Capiox CX-SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8-inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21 degrees C) with fresh bovine blood. Blood samples for plasma-free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP-80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8 degrees C) and the most with the SJM pump (3.8 degrees C). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.
Comparison of subcutaneous and intravenous continuous glucose monitoring accuracy in an operating room and an intensive care unit.
Munekage, Masaya; Yatabe, Tomoaki; Sakaguchi, Masahiko; Kitagawa, Hiroyuki; Tamura, Takahiko; Namikawa, Tsutomu; Hanazaki, Kazuhiro
Although we have used an intravenous continuous glucose monitor for blood glucose management, a previous study reported that a subcutaneous continuous glucose monitor was also reliable for use in critically ill patients. The aim of this study was to compare the subcutaneous and intravenous continuous glucose monitors. This was an observational trial (UMIN-CTR, ID:000013338). We included patients who were admitted to our intensive care units (ICU) after hepato-biliary pancreatic surgery. Continuous blood glucose measurement was performed from the beginning of the operation to ICU discharge using the intravenous continuous monitor STG-55 (Nikkiso, Tokyo, Japan) and the subcutaneous continuous monitor iPro2 (Medtronic Japan, Tokyo, Japan). The STG-55 measured the glucose level in real time, and the iPro2 measured this every 5 min. We compared glucose levels obtained using the two devices every 5 min using a Bland-Altman plot and a regression analyses. A total of 3592 comparative samples in 15 cases were analyzed. The mean glucose level measured using the STG-55 was 139 ± 21 mg/dl, and that measured using the iPro2 was 144 ± 31 mg/dl. A linear regression line had the equation of the form y = 0.225x + 106. The coefficient of determination was 0.11, and the F-test significance level was set as p < 0.01. The mean of the differences was -5.2 mg/dl, with a 95 % agreement limit of -67 to + 57 mg/dL. The percent error was 44 %. In conclusion, the current study suggests that subcutaneous and intravenous continuous glucose monitoring was not highly correlated during either surgery or ICU stay.
The changes of the frequency specific impedance of the human body due to the resonance in the kHz range in cancer diagnostics
NASA Astrophysics Data System (ADS)
Michalak, K. P.; Nawrocka-Bogusz, H.
The frequency-specific absorption of kHz signals has been postulated for different tissues, trace elements, vitamins, toxins, pathogens, allergens etc. for low-power (μV) signals. An increase in the impedance of the human body is observed only up to the given power of the applied signal. The highest amplification of the given signal being damped by the body makes it possible to determine the intensity of the given process in the body (e.g. amount of the toxin, trace element, intensity of the allergy) being connected with a given frequency spectrum of the signal. The mechanism of frequency-specific absorption can be explained by means of the Quantum Field Theory being applied to the structure of the water. Substantially high coincidence between the frequencies of the rotation of free quasi-excited electrons in coherent domains of water and the frequencies being used in the MORA diagnostics (Med-Tronic GmbH, EN ISO 13485, EN ISO 9001) can be observed. These frequencies are located in the proximity of f = 7kHz · i (i = 1,3,5,7,...). This fact suggests that the coherent domains with the admixtures of the given substances create structure-specific coherent domains that possess frequency-specific absorption spectra. The diagnostic tool called "MORA System diagnosis" was used to investigate 102 patients with different types and stages of cancer. Many signals were observed to be absorbed by many cancer patients, e.g.: 'Cellular defense system', 'Degeneration tendencies', Manganese, Magnesium, Zinc, Selenium, Vitamin E, Glutamine, Glutathione, Cysteine, Candida albicans, Mycosis. The results confirm the role of oxidative stress, immunological system deficiency and mitochondria malfunction in the development of cancer.
Chronic multisite brain recordings from a totally implantable bidirectional neural interface: experience in 5 patients with Parkinson's disease.
Swann, Nicole C; de Hemptinne, Coralie; Miocinovic, Svjetlana; Qasim, Salman; Ostrem, Jill L; Galifianakis, Nicholas B; Luciano, Marta San; Wang, Sarah S; Ziman, Nathan; Taylor, Robin; Starr, Philip A
OBJECTIVE Dysfunction of distributed neural networks underlies many brain disorders. The development of neuromodulation therapies depends on a better understanding of these networks. Invasive human brain recordings have a favorable temporal and spatial resolution for the analysis of network phenomena but have generally been limited to acute intraoperative recording or short-term recording through temporarily externalized leads. Here, the authors describe their initial experience with an investigational, first-generation, totally implantable, bidirectional neural interface that allows both continuous therapeutic stimulation and recording of field potentials at multiple sites in a neural network. METHODS Under a physician-sponsored US Food and Drug Administration investigational device exemption, 5 patients with Parkinson's disease were implanted with the Activa PC+S system (Medtronic Inc.). The device was attached to a quadripolar lead placed in the subdural space over motor cortex, for electrocorticography potential recordings, and to a quadripolar lead in the subthalamic nucleus (STN), for both therapeutic stimulation and recording of local field potentials. Recordings from the brain of each patient were performed at multiple time points over a 1-year period. RESULTS There were no serious surgical complications or interruptions in deep brain stimulation therapy. Signals in both the cortex and the STN were relatively stable over time, despite a gradual increase in electrode impedance. Canonical movement-related changes in specific frequency bands in the motor cortex were identified in most but not all recordings. CONCLUSIONS The acquisition of chronic multisite field potentials in humans is feasible. The device performance characteristics described here may inform the design of the next generation of totally implantable neural interfaces. This research tool provides a platform for translating discoveries in brain network dynamics to improved neurostimulation
New generation extracorporeal membrane oxygenation with MedTech Mag-Lev, a single-use, magnetically levitated, centrifugal blood pump: preclinical evaluation in calves.
Fujiwara, Tatsuki; Nagaoka, Eiki; Watanabe, Taiju; Miyagi, Naoto; Kitao, Takashi; Sakota, Daisuke; Mamiya, Taichi; Shinshi, Tadahiko; Arai, Hirokuni; Takatani, Setsuo
We have evaluated the feasibility of a newly developed single-use, magnetically levitated centrifugal blood pump, MedTech Mag-Lev, in a 3-week extracorporeal membrane oxygenation (ECMO) study in calves against a Medtronic Bio-Pump BPX-80. A heparin- and silicone-coated polypropylene membrane oxygenator MERA NHP Excelung NSH-R was employed as an oxygenator. Six healthy male Holstein calves with body weights of about 100 kg were divided into two groups, four in the MedTech group and two in the Bio-Pump group. Under general anesthesia, the blood pump and oxygenator were inserted extracorporeally between the main pulmonary artery and the descending aorta via a fifth left thoracotomy. Postoperatively, both the pump and oxygen flow rates were controlled at 3 L/min. Heparin was continuously infused to maintain the activated clotting time at 200-240 s. All the MedTech ECMO calves completed the study duration. However, the Bio-Pump ECMO calves were terminated on postoperative days 7 and 10 because of severe hemolysis and thrombus formation. At the start of the MedTech ECMO, the pressure drop across the oxygenator was about 25 mm Hg with the pump operated at 2800 rpm and delivering 3 L/min flow. The PO2 of the oxygenator outlet was higher than 400 mm Hg with the PCO2 below 45 mm Hg. Hemolysis and thrombus were not seen in the MedTech ECMO circuits (plasma-free hemoglobin [PFH] < 5 mg/dL), while severe hemolysis (PFH > 20 mg/dL) and large thrombus were observed in the Bio-Pump ECMO circuits. Plasma leakage from the oxygenator did not occur in any ECMO circuits. Three-week cardiopulmonary support was performed successfully with the MedTech ECMO without circuit exchanges. The MedTech Mag-Lev could help extend the durability of ECMO circuits by the improved biocompatible performances.
Creating new growth platforms.
Laurie, Donald L; Doz, Yves L; Sheer, Claude P
Sooner or later, most companies can't attain the growth rates expected by their boards and CEOs and demanded by investors. To some extent, such businesses are victims of their own successes. Many were able to sustain high growth rates for a long time because they were in high-growth industries. But once those industries slowed down, the businesses could no longer deliver the performance that investors had come to take for granted. Often, companies have resorted to acquisition, though this strategy has a discouraging track record. Over time, 65% of acquisitions destroy more value than they create. So where does real growth come from? For the past 12 years, the authors have been researching and advising companies on this issue. With the support of researchers at Harvard Business School and Insead, they instituted a project titled "The CEO Agenda and Growth". They identified and approached 24 companies that had achieved significant organic growth and interviewed their CEOs, chief strategists, heads of R&D, CFOs, and top-line managers. They asked, "Where does your growth come from?" and found a consistent pattern in the answers. All the businesses grew by creating new growth platforms (NGPs) on which they could build families of products and services and extend their capabilities into multiple new domains. Identifying NGP opportunities calls for executives to challenge conventional wisdom. In all the companies studied, top management believed that NGP innovation differed significantly from traditional product or service innovation. They had independent, senior-level units with a standing responsibility to create NGPs, and their CEOs spent as much as 50% of their time working with these units. The payoff has been spectacular and lasting. For example, from 1985 to 2004, the medical devices company Medtronic grew revenues at 18% per year, earnings at 20%, and market capitalization at 30%.
Spinal Cord Stimulation (SCS)—The Implantable Systems Performance Registry (ISPR)
Schultz, David M.; Calodney, Aaron K.; Mogilner, Alon Y.; Weaver, Todd W.; Wells, Michelle D.; Stromberg, E. Katherine; Roediger, Mollie P.; Sasaki, John T.
Objectives The Implantable Systems Performance Registry (ISPR) was created to monitor the product performance of Medtronic Spinal Cord Stimulation (SCS) and implanted intrathecal drug infusion systems available in the United States. Materials and Methods Data were collected on 2605 patients from 44 centers from various geographic regions across the United States implanting and following patients with SCS systems between June 25, 2004 and January 31, 2014. Actuarial life table methods are used to estimate device performance over time. Of the 2605 patients, 1490 (57.2%) were female, 1098 (42.1%) were male and 17 (0.7%) did not provide gender data. The average age at enrollment was 56.3 years (range: 4–97, SD = 14.3) and average follow‐up time was 20.1 months (SD = 22.5). Results Currently the estimates of device survival from neurostimulator‐related events exceed 97% for all neurostimulator models across the applicable follow‐up time points and all applicable extension models had greater than 95% survival from extension events. The majority of product performance events were lead‐related. At 5 years of follow‐up, all applicable lead families, with the exception of the Pisces‐Quad LZ family, had greater than 75% survival from lead events. Conclusions The ISPR is designed to serve as an ongoing source of system and device‐related information with a focus on “real‐world” safety and product performance. ISPR data continue to be used to guide future product development efforts aimed at improving product reliability and quality. PMID:27730706
Sixty Hertz Neurostimulation Amplifies Subthalamic Neural Synchrony in Parkinson’s Disease
Blumenfeld, Zack; Velisar, Anca; Miller Koop, Mandy; Hill, Bruce C.; Shreve, Lauren A.; Quinn, Emma J.; Kilbane, Camilla; Yu, Hong; Henderson, Jaimie M.; Brontë-Stewart, Helen
High frequency subthalamic nucleus (STN) deep brain stimulation (DBS) improves the cardinal motor signs of Parkinson’s disease (PD) and attenuates STN alpha/beta band neural synchrony in a voltage-dependent manner. While there is a growing interest in the behavioral effects of lower frequency (60 Hz) DBS, little is known about its effect on STN neural synchrony. Here we demonstrate for the first time that during intra-operative 60 Hz STN DBS, one or more bands of resting state neural synchrony were amplified in the STN in PD. We recorded intra-operative STN resting state local field potentials (LFPs) from twenty-eight STNs in seventeen PD subjects after placement of the DBS lead (model 3389, Medtronic, Inc.) before and during three randomized neurostimulation sets (130 Hz/1.35V, 130 Hz/2V, 60 Hz/2V). During 130 Hz/2V DBS, baseline (no DBS) STN alpha (8 – 12 Hz) and beta (13 – 35 Hz) band power decreased (N=14, P < 0.001 for both), whereas during 60 Hz/2V DBS, alpha band and peak frequency power increased (P = 0.012, P = 0.007, respectively). The effect of 60 Hz/2V DBS opposed that of power-equivalent (130 Hz/1.35V) DBS (alpha: P < 0.001, beta: P = 0.006). These results show that intra-operative 60 Hz STN DBS amplified whereas 130 Hz STN DBS attenuated resting state neural synchrony in PD; the effects were frequency-specific. We demonstrate that neurostimulation may be useful as a tool to selectively modulate resting state resonant bands of neural synchrony and to investigate its influence on motor and non-motor behaviors in PD and other neuropsychiatric diseases. PMID:25807463