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The work developed in this paper presents a comparison between three different phase detection algorithms in order to study the benefits of using each of them when they are applied inside a sensorless rotor position estimation technique. In particular we will analyse the various aspects related to the use of each single algorithm when it is applied into a specific model-based sensorless strategy and when we also take into account the typical impairments affecting the implementation of the real setup, such as unwanted harmonic components and measurement offsets. As a first step a short overview on each phase-detection algorithm under consideration will be given and subsequently the proposed model-based estimation technique will be presented. As a second step the three algorithms are analyzed in detail highlighting their dynamical performances and their robustness properties against implementative knots, in particular through the use of software simulations and real-time simulations reproducing the specific test case of a five-phase motor.

The present paper shows a rotor position estimation technique for a five-phase permanent magnet synchronous motor based on a back-EMF observer, focusing the attention on the design criteria that could be used to construct the sensorless strategy. Due to the polyphase structure of the machine this estimation method deals with a proper linear transformation which allows representing the five-phase motor through an equivalent two-phase model. After a short overview on the back-EMF model for the five-phase motor, the linear transformation and the observer-based estimation technique are presented. The analysis emphasizes on the choice of the observation dynamics through a proper design strategy of the related gain matrix and on some robustness criteria useful to enhance the sensorless strategy. Simulation and experimental results showing the response of the observer during transient and steady-state operation are presented.

This paper presents a rotor position estimation technique for a five-phase permanent magnet synchronous motor with independent phases, based on a back-EMF observer. The method involves the use of a proper linear transformation which allows representing the five-phase motor by an equivalent two-phase model. Due to its characteristics, the sensorless strategy can be used in multi-phase motors having non-sinusoidal back-EMF shape, such is the case of brushless DC motors used in fault-tolerant applications. After an overview of the back-EMF model for the five-phase motor, the linear transformation and the observer-based estimation technique are presented. Experimental results show the overall performance during transient and steady-state operation.

Patients who fail noninvasive ventilation are generally intubated and are then subjected to complications of invasive mechanical ventilation. With transtracheal open ventilation, ventilator support is delivered through an uncuffed small bore minitracheostomy tube, which eliminates pooling of secretions above the cuff and thus reduces the risk of tracheobronchial microbial colonization.To compare transtracheal open ventilation (treatment group) with conventional invasive ventilation (control group) in patients with exacerbation of chronic obstructive pulmonary disease who initially failed noninvasive ventilation.Patients were randomized to receive trans-tracheal open ventilation (n=19) or conventional invasive ventilation (n=20).There was no difference in arterial blood gases after 1 and 30 h between the two groups. Two patients receiving transtracheal open ventilation and 13 undergoing conventional ventilation had complications (p0.0001). Compared with conventional ventilation, transtracheal open ventilation significantly decreased both the duration of mechanical ventilation (7.6+/-4.7 vs. 18.6+/-10.6 d, p0.0001) and length of stay in the intensive care unit (10.2+/-4.5 vs. 21.3+/-9.7 d, p0.0001).Transtracheal open ventilation was as effective as conventional ventilation in maintaining adequate gas exchange and reducing complications, duration of mechanical ventilation, and intensive care unit length of stay.

Traumatic injury and trauma deaths have been worldwide considered a major health problem [1]. The World Health Organization estimates that 16 000 people die everyday from trauma injuries, and for every person who dies, several thousands more are injured, many of them with permanent sequelae. Injury accounts for 16% of the global burden of disease [2].

Objective: To evaluate the efficacy of mechanical ventilation administered through a small-bore, uncuffed tracheotomy tube, so-called transtracheal open ventilation (TOV), in comparison with conventional mechanical ventilation via a cuffed tracheal tube (endotracheal invasive ventilation, EIV). Design: Physiologic study. Setting: Intensive care unit of a referral trauma center. Patients: Ten acute quadriplegic patients. Interventions: In acute quadriplegic patients receiving EIV, TOV was subsequently applied via an uncuffed, small-bore tube (internal diameter of 4 or 5 mm). Measurements and Main Results: Compared with EIV, arterial blood gases were not significantly different after 1 hr of TOV (PaO 2 /FIO 2 , 222.8 ± 60.9 vs. 218.5 ± 60.3; PacO 2 , 37.8 ± 7.1 torr [5.04 ± 0.95 kPa] vs. 35.5 ± 6.8 torr [4.73 ± 0.91 kPa], for EIV and TOV, respectively). Respiratory rate (19.5 ± 4.7 vs. 19.6 ± 5 breaths/min) and inspiratory effort (pressure-time product of esophageal pressure during a 1-min period, 125.9 ± 48.4 vs. 112.8 ± 36.4 cm H 2 O.sec -1 .min -1 ) were also no different between the two modes. After 24 hrs of TOV, compared with EIV and TOV after 1 hr, respiratory rate and arterial blood gases remained stable, and the pressure-time product of esophageal pressure during a 1-min period was slightly, but significantly, reduced (83.5 ± 16.6 cm H 2 O.sec -1 .min -1 , p

Recently it has been shown in animal models of amyotrophic lateral sclerosis (ALS) that stem cells significantly slow the progression of the disease and prolong survival. We have evaluated the feasibility and safety of a method of intraspinal cord implantation of autologous mesenchymal stem cells (MSCs) in a few well-monitored patients with ALS.Bone marrow collection was performed according to the standard procedure by aspiration from the posterior iliac crest. Ex vivo expansion of mesenchymal stem cells was induced according to Pittenger's protocol. The cells were suspended in 2 ml of autologous cerebrospinal fluid and transplanted into the spinal cord by a micrometric pump injector.No patient manifested major adverse events such as respiratory failure or death. Minor adverse events were intercostal pain irradiation (4 patients) which was reversible after a mean period of three days after surgery, and leg sensory dysesthesia (5 patients) which was reversible after a mean period of six weeks after surgery. No modification of the spinal cord volume or other signs of abnormal cell proliferation were observed.Our results appear to demonstrate that the procedures of ex vivo expansion of autologous mesenchymal stem cells and of transplantation into the spinal cord of humans are safe and well tolerated by ALS patients.

Noninvasive neurally adjusted ventilatory assist by helmet (hNAVA) was shown to improve, compared with pressure support ventilation by helmet (hPSV), patient-ventilator interaction and synchrony in patients with acute respiratory failure without affecting peak electrical activity of the diaphragm (EAdipeak) [1]. Recently, a new helmet is available, which improves pressurization during hPSV. We propose a new setting of hNAVA (hNAVA15) to achieve further improvement. We compare hPSV, hNAVA and hNAVA15, all delivered using the new helmet, with respect to patient's dyspnea, assessed by a visual analogue scale (VASd), arterial blood gases (ABGs), EAdipeak, rate of ventilator pressurization and triggering performance.

The management of refractory post-traumatic cerebral oedema remains a frustrating endeavour for the neurosurgeon and the intensivist. Mortality and morbility rates remain high, despite refinements in medical and pharmacological means of controlling intracranial hypertension.

Multi-organ dysfunction syndrome (MODS) is the most frequent cause of death in patients admitted to intensive care units. Severe sepsis and septic shock are the primary causes of MODS and develop as a result of the host response to infection and to bacterial wall components, such as the lipid-A containing lipopolysaccharide (LPS). The host response involves both the cellular and humoral arms of the immune system and the generation of pro- and anti-inflammatory molecules. The anti-inflammatory response may lead to a state of 'immunoparalysis'. Continuous renal replacement therapies (CRRT) remove several soluble pro- and anti-inflammatory mediators simultaneously, albeit at low rates. However, large pore membranes, such as those used for plasmafiltration, may enhance cytokine removal and clearance. We recently observed that the use of coupled plasma filtration adsorption (CPFA) improved survival in a rabbit model of septic shock [1]. The outcome was not correlated with single cytokines or mediators (such as TNFa, platelet-activating factor or endotoxin), but rather with a global sepsis severity score. The results of this study suggested that a non-selective removal of various septic mediators was beneficial. A pilot, prospective, cross-over study tested the hypothesis that CPFA combined with hemodialysis might exert similar beneficial effects on hemodynamics and leukocyte responsiveness in humans with established septic shock and that it might prove superior to continuous veno-venous hemodiafiltration (CVVHDF) alone [2].

Elevated level of osteoprotegerin (OPG), a pleiotropic cytokine involved in bone metabolism, has been associated with coronary heart disease and higher cardiovascular mortality. Because cardiovascular disorders are recognized risk factors for dementia, the study of OPG as a disease marker in vascular dementia (VaD) and Alzheimer's disease (AD) seemed worthy of investigation. OPG concentration was determined by ELISA in an Italian cohort consisting of 39 VaD patients, 36 AD patients, and 39 non-demented controls strictly matched for age and gender. Plasma OPG levels were positively related to age in both demented and non-demented persons. OPG concentrations were significantly higher in both VaD (median: 4.75 pmol/l; interquartile range: 3.42-6.85 pmol/l; P