text: http://uu.diva-portal.org/smash/resultList.jsf?query=&language=en&searchType=SIMPLE&noOfRows=50&sortOrder=author_sort_asc&sortOrder2=title_sort_asc&onlyFullText=false&sf=all&aq=%5B%5B%7B%22personId%22%3A%22authority-person%3A22115%22%7D%5D%5D&aqe=%5B%5D&aq2=%5B%5B%5D%5D&af=%5B%5D
  Polish Acad Sci, Nalecz Inst Biocybemet & Biomed Engn, Trojdena 4, PL-02109 Warsaw, Poland.
  Polish Acad Sci, Nalecz Inst Biocybemet & Biomed Engn, Trojdena 4, PL-02109 Warsaw, Poland;Lawson Hlth Res Inst, Imaging Div, London, ON N61 4172, Canada;Western Univ, Dept Med Biophys, London, ON N6A 51, Canada.
  Multiwavelength time-resolved near-infrared spectroscopy of the adult head: assessment of intracerebral and extracerebral absorption changes2018In: Biomedical Optics Express, ISSN 2156-7085, E-ISSN 2156-7085, Vol. 9, no 7, p. 2974-2993Article in journal (Refereed)
  An optical technique based on diffuse reflectance measurement combined with indocyanine green (ICG) bolus tracking is extensively tested as a method for the clinical assessment of brain perfusion at the bedside. We report on multiwavelength time-resolved diffuse reflectance spectroscopy measurements carried out on the head of a healthy adult during the intravenous administration of a bolus of ICG. Intracerebral and extracerebral changes in absorption were estimated from an analysis of changes in statistical moments (total number of photons, mean time of flight and variance) of the distributions of times of flight (DTOF) of photons recorded simultaneously at 16 wavelengths from the range of 650-850 nm using sensitivity factors estimated by diffusion approximation based on a layered model of the studied medium. We validated the proposed method in a series of phantom experiments and in-vivo measurements. The results obtained show that changes in the concentration of the ICG can be assessed as a function of time of the experiment and depth in the tissue. Thus, the separation of changes in ICG concentration appearing in intra-and extracerebral tissues can be estimated from optical data acquired at a single source-detector pair of fibers/fiber bundles positioned on the surface of the head.
  The roles of mid-myocardial and epicardial cells in T-wave alternans development: a simulation study2018In: Biomedical engineering online, ISSN 1475-925X, E-ISSN 1475-925X, Vol. 17, article id 57 Article in journal (Refereed)
  Polish Acad Sci, Nalecz Inst Biocybernet & Biomed Engn, Trojdena 4, PL-02109 Warsaw, Poland.
  Polish Acad Sci, Nalecz Inst Biocybernet & Biomed Engn, Trojdena 4, PL-02109 Warsaw, Poland;Western Univ, Dept Med Biophys, London, ON N6A 5C1, Canada;Lawson Hlth Res Inst, Imaging Div, London, ON N6A 4V2, Canada.
  Frequency analysis of oscillations in cerebral hemodynamics measured by time domain near infrared spectroscopy2019In: Biomedical Optics Express, ISSN 2156-7085, E-ISSN 2156-7085, Vol. 10, no 2, p. 761-771Article in journal (Refereed)
  In this paper, we propose the application of time-domain near-infrared spectroscopy to the assessment of oscillations in cerebral hemodynamics. These oscillations were observed in the statistical moments of the distributions of time of flight of photons (DTOFs) measured on the head. We analyzed the zeroth and second centralized moments of DTOFs (total number of photons and variance) to obtain their spectra to provide parameters for the frequency components of microcirculation, which differ between the extracerebral and intracerebral layers of the head. Analysis of these moments revealed statistically significant differences between a control group of healthy subjects and a group of patients with severe neurovascular disorders, which is a promising result for the assessment of cerebral microcirculation and cerebral autoregulation mechanisms.
  Polish Acad Sci, Nalecz Inst Biocybernet & Biomed Engn, PL-02109 Warsaw, Poland..
  Treszczanowicz, Joanna
  Warsaw Praski Hosp, Dept Intens Care & Anesthesiol, PL-03401 Warsaw, Poland..
  Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care. Warsaw Praski Hosp, Dept Intens Care & Anesthesiol, PL-03401 Warsaw, Poland..
  Optimization of the method for assessment of brain perfusion in humans using contrast-enhanced reflectometry: multidistance time-resolved measurements2015In: Journal of Biomedical Optics, ISSN 1083-3668, E-ISSN 1560-2281, Vol. 20, no 10, article id 106013Article in journal (Refereed)
  The aim of the study was to determine optimal measurement conditions for assessment of brain perfusion with the use of optical contrast agent and time-resolved diffuse reflectometry in the near-infrared wavelength range. The source-detector separation at which the distribution of time of flights (DTOF) of photons provided useful information on the inflow of the contrast agent to the intracerebral brain tissue compartments was determined. Series of Monte Carlo simulations was performed in which the inflow and washout of the dye in extra-and intracerebral tissue compartments was modeled and the DTOFs were obtained at different source-detector separations. Furthermore, tests on diffuse phantoms were carried out using a time-resolved setup allowing the measurement of DTOFs at 16 source-detector separations. Finally, the setup was applied in experiments carried out on the heads of adult volunteers during intravenous injection of indocyanine green. Analysis of statistical moments of the measured DTOFs showed that the source-detector separation of 6 cm is recommended for monitoring of inflow of optical contrast to the intracerebral brain tissue compartments with the use of continuous wave reflectometry, whereas the separation of 4 cm is enough when the higher-order moments of DTOFs are available.
  Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care. Akademiska Hospital, Uppsala, Sweden .
  Med Univ Warsaw, Dept Forens Med, Warsaw, Poland..
  Med Univ Warsaw, Dept Descript & Clin Anat, Warsaw, Poland..
  Human skull translucency: post mortem studies2016In: Biomedical Optics Express, ISSN 2156-7085, E-ISSN 2156-7085, Vol. 7, no 12, p. 5010-5020Article in journal (Refereed)
  Measurements of optical translucency of human skulls were carried out. An incandescent light source and a CCD camera were used to measure the distribution of light transmitted through the skull in 10 subjects post-mortem. We noticed that intra-individual differences in optical translucency may be up to 100 times but inter-individual translucency differences across the skull reach 105 times. Based on the measurement results, a "theoretical" experiment was simulated. Monte-Carlo calculations were used in order to evaluate the influence of the differences in optical translucency of the skull on results of NIRS measurements. In these calculations a functional stimulation was done, in which the oxyhemoglobin and deoxyhemoglobin concentrations in the brain cortex change by 5 mu M and -5 mu M respectively. The maximal discrepancies between assumed hemoglobin concentration changes and hemoglobin concentration changes estimated with Monte-Carlo simulation may reach 50% depending of the translucency of the skull.
  Prospective assessment of the standardized mortality ratio (SMR) as a measure of quality of care in an intensive care unit - a single-centre study2015In: ANAESTHESIOLOGY INTENSIVE THERAPY, ISSN 1642-5758, Vol. 47, no 4, p. 328-332Article in journal (Refereed)
  Mortality rate is higher in Polish intensive care units than in other European countries2017In: Intensive Care Medicine, ISSN 0342-4642, E-ISSN 1432-1238, Vol. 43, no 9, p. 1430-1432Article in journal (Other academic)
  Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care. Med Univ Warsaw, Dept Anesthesiol & Intens Care 1, Warsaw, Poland.
  Med Univ Warsaw, Dept Anesthesiol & Intens Care 1, Warsaw, Poland..
  Med Univ Warsaw, Dept Anesthesiol & Intens Care 1, Warsaw, Poland.;Gruca Orthoped & Trauma Teaching Hosp, Ctr Postgrad Med Educ, Dept Anesthesiol & Intens Care, Otwock, Poland..
  Polish Acad Sci, Inst Comp Sci, Jana Kazimierza 5, PL-01248 Warsaw, Poland..
  Perioperative analgesia after intrathecal fentanyl and morphine or morphine alone for cesarean section: A randomized controlled study2017In: Medicine (Baltimore, Md.), ISSN 0025-7974, E-ISSN 1536-5964, Vol. 96, no 48, article id e8892 Article in journal (Refereed)
  Methods: This prospective, randomized, double-blind, parallel-group study included 60 parturients scheduled for elective CS. Spinal anesthesia consisted of bupivacaine with either morphine 100 mu g (M group), or fentanyl 25 mu g and morphine 100 mu g (FM group). The frequency of intraoperative pain and pethidine consumption in the 24 hours postoperatively was recorded.
  Results: Fewer patients in the FM group required additional intraoperative analgesia (P < .01, relative risk 0.06, 95% confidence interval [CI] 0.004-1.04). The FM group was noninferior to the M group for 24-hour opioid consumption (95% CI -10.0 mg to 45.7 mg, which was below the prespecified boundary of 50 mg). Pethidine consumption in postoperative hours 1 to 12 was significantly higher in the FM group (P=.02). Postoperative nausea and vomiting (PONV) were more common in the FM group (P=.01). Visual analog scale scores, effective analgesia, Apgar scores, and rates of pruritus and respiratory depression were similar between the groups.
  Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care. Med Univ Warsaw, Dept Anaesthesiol & Intens Care, Lindleya 4th St, Warsaw, Poland..
  Med Univ Warsaw, Dept Anaesthesiol & Intens Care, Lindleya 4th St, Warsaw, Poland..
  Med Univ Warsaw, Dept Anaesthesiol & Intens Care, Lindleya 4th St, Warsaw, Poland.;Prof Gruca Teaching Hosp, Dept Anaesthesiol & Intens Care, Postgrad Med Educ Ctr, Konarskiego 13, Otwock, Poland..
  Med Univ Warsaw, Dept Obstet & Gynaecol 1, Warsaw, Poland..
  Analgesic efficacy of intrathecal fentanyl during the period of highest analgesic demand after cesarean section A randomized controlled study2016In: Medicine (Baltimore, Md.), ISSN 0025-7974, E-ISSN 1536-5964, Vol. 95, no 24, article id e3827 Article in journal (Refereed)
  Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Surgical Sciences, Anaesthesiology and Intensive Care. Med Univ Warsaw, Dept Anesthesiol & Intens Care 1, Lindleya 4 St, Warsaw, Poland.
  Polish Acad Sci, Nalecz Inst Biocybernet & Biomed Engn, Ks Trojdena 4 St, PL-02109 Warsaw, Poland.
  Kacprzak, Michel
  Confirmation of brain death using optical methods based on tracking of an optical contrast agent: assessment of diagnostic feasibility2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 7332 Article in journal (Refereed)
  We aimed to determine whether optical methods based on bolus tracking of an optical contrast agent are useful for the confirmation of cerebral circulation cessation in patients being evaluated for brain death. Different stages of cerebral perfusion disturbance were compared in three groups of subjects: controls, patients with posttraumatic cerebral edema, and patients with brain death. We used a time-resolved near-infrared spectroscopy setup and indocyanine green (ICG) as an intravascular flow tracer. Orthogonal partial least squares-discriminant analysis (OPLS-DA) was carried out to build statistical models allowing for group separation. Thirty of 37 subjects (81.1%) were classified correctly (8 of 9 control subjects, 88.9%; 13 of 15 patients with edema, 86.7%; and 9 of 13 patients with brain death, 69.2%; p < 0.0001). Depending on the combination of variables used in the OPLS-DA model, sensitivity, specificity, and accuracy were 66.7-92.9%, 81.8-92.9%, and 77.3-89.3%, respectively. The method was feasible and promising in the demanding intensive care unit environment. However, its accuracy did not reach the level required for brain death confirmation. The potential usefulness of the method may be improved by increasing the depth of light penetration, confirming its accuracy against other methods evaluating cerebral flow cessation, and developing absolute parameters for cerebral perfusion.