8 research outputs found
ПОЛИОЛАТЫ КРЕМНИЯ И ТИТАНА – НОВЫЕ БИОСОВМЕСТИМЫЕ ПРЕКУРСОРЫ В БИОМИМЕТИЧЕСКОЙ ЗОЛЬ-ГЕЛЬ МИНЕРАЛИЗАЦИИ ПОЛИСАХАРИДОВ
Работа выполнена в соответствии с темой Государственного задания, проект № АААА-А19-119011790134-1
Tightly Integrated Doppler Velocity Log Aided Inertial Navigational System
Background:
Underwater navigation is an important aid for many industries, including oil and gas exploration, marine and subsea operations. These industries are highly dependent on a detailed map of the seabed, which can be supplied by AUVs, in order to conduct underwater operations safely and reliably. One commonly used velocity sensor on AUVs are called Doppler Velocity Log (DVL). Such sensors utilize the Doppler shift in sonic pulses to calculate vehicle velocities for system navigation.
The main focus in this thesis has been on examining the quality of a tightly integrated DVL (referred to as Method 1) aided INS and to compare the quality of this method with an cartesian DVL (referred to as Method 2). Testing the performance of the two methods on real sensor data.
Method:
Analyses and simulations were carried out by the use of the generic aided inertial navigation software developed by Kongsberg Maritime, NavLab. NavLab is implemented in Matlab, and is used for performing navigation calculations for navigational purposes. Particular attention was given to the velocity measurements from the DVL device, as the velocity measurements bounds the velocity error of the navigation system.
Findings:
The proposed implementation of the tightly integrated DVL was proven to be a feasible method, as the Extended Kalman filter (EKF) was able to estimate velocities in transducer beams with an approximate mean errors of 0.02 %. However, the EKF was not tuned for Method 1, meaning that the internal Kalman filter dynamics for Method 1 presented in this thesis are not sufficiently accounted for, and lead to that the navigational error did not decrease when using Method 1, relative to Method 2. This leads to a lack of a firm conclusion between the two methods. However, the work presented in this thesis forms a solid foundation for further research within the field of velocity and position estimation for AUVs in Kongsberg Maritime and the important issue of Extended Kalman filter tuning in Method 1 has been illuminated
Is the supine position associated with loss of airway patency in unconscious trauma patients? A systematic review and meta-analysis
Background
Airway compromise is a leading cause of death in unconscious trauma patients. Although endotracheal intubation is regarded as the gold standard treatment, most prehospital providers are not trained to perform ETI in such patients. Therefore, various lateral positions are advocated for unconscious patients, but their use remains controversial in trauma patients. We conducted a systematic review to investigate whether the supine position is associated with loss of airway patency compared to the lateral position.
Methods
The review protocol was published in the PROSPERO database (Reg. no. CRD42012001190). We performed literature searches in PubMed, Medline, EMBASE, Cochrane Library, CINAHL and British Nursing Index and included studies related to airway patency, reduced level of consciousness and patient position. We conducted meta-analyses, where appropriate. We graded the quality of evidence with the GRADE methodology. The search was updated in June 2014.
Results
We identified 1,306 publications, 39 of which were included for further analysis. Sixteen of these publications were included in meta-analysis. We did not identify any studies reporting direct outcome measures (mortality or morbidity) related to airway compromise caused by the patient position (lateral vs. supine position) in trauma patients or in any other patient group. In studies reporting only indirect outcome measures, we found moderate evidence of reduced airway patency in the supine vs. the lateral position, which was measured by the apnea/hypopnea index (AHI). For other indirect outcomes, we only found low or very low quality evidence.
Conclusions
Although concerns other than airway patency may influence how a trauma patient is positioned, our systematic review provides evidence supporting the long held recommendation that unconscious trauma patients should be placed in a lateral position
Post-anaesthesia pulmonary complications after use of muscle relaxants (POPULAR): a multicentre, prospective observational study
Background Results from retrospective studies suggest that use of neuromuscular blocking agents during general
anaesthesia might be linked to postoperative pulmonary complications. We therefore aimed to assess whether the use
of neuromuscular blocking agents is associated with postoperative pulmonary complications.
Methods We did a multicentre, prospective observational cohort study. Patients were recruited from 211 hospitals in
28 European countries. We included patients (aged ≥18 years) who received general anaesthesia for any in-hospital
procedure except cardiac surgery. Patient characteristics, surgical and anaesthetic details, and chart review at discharge
were prospectively collected over 2 weeks. Additionally, each patient underwent postoperative physical examination
within 3 days of surgery to check for adverse pulmonary events. The study outcome was the incidence of postoperative
pulmonary complications from the end of surgery up to postoperative day 28. Logistic regression analyses were
adjusted for surgical factors and patients’ preoperative physical status, providing adjusted odds ratios (ORadj) and
adjusted absolute risk reduction (ARRadj). This study is registered with ClinicalTrials.gov, number NCT01865513.
Findings Between June 16, 2014, and April 29, 2015, data from 22803 patients were collected. The use of neuromuscular
blocking agents was associated with an increased incidence of postoperative pulmonary complications in patients who
had undergone general anaesthesia (1658 [7·6%] of 21694); ORadj 1·86, 95% CI 1·53–2·26; ARRadj –4·4%, 95% CI
–5·5 to –3·2). Only 2·3% of high-risk surgical patients and those with adverse respiratory profiles were anaesthetised
without neuromuscular blocking agents. The use of neuromuscular monitoring (ORadj 1·31, 95% CI 1·15–1·49;
ARRadj –2·6%, 95% CI –3·9 to –1·4) and the administration of reversal agents (1·23, 1·07–1·41; –1·9%, –3·2 to –0·7)
were not associated with a decreased risk of postoperative pulmonary complications. Neither the choice of sugammadex
instead of neostigmine for reversal (ORadj 1·03, 95% CI 0·85–1·25; ARRadj –0·3%, 95% CI –2·4 to 1·5) nor extubation at
a train-of-four ratio of 0·9 or more (1·03, 0·82–1·31; –0·4%, –3·5 to 2·2) was associated with better pulmonary outcomes.
Interpretation We showed that the use of neuromuscular blocking drugs in general anaesthesia is associated with an
increased risk of postoperative pulmonary complications. Anaesthetists must balance the potential benefits of
neuromuscular blockade against the increased risk of postoperative pulmonary complications