Метод бесконтактной оценки паттерна дыхания человека при помощи стереопары

The development of contactless monitoring methods of human vital signs is an important goal for modern medicine. The particular relevance of this issue appears with the control of the patient at home on their own, for example, to estimate the parameters of breathing during sleep, quality assessment and identification of various kinds of sleep disorders, such as, for example, sleep apnea disorder (a condition, which is characterized by the cessation of pulmonary ventilation more than for 10 seconds and fall of blood oxygen saturation).In this article we have implemented and tested an algorithm for non-contact monitoring of breathing pattern by two entrenched webcams aimed at the person. The algorithm is based on using the methods of computer vision and processing of video sequences.Authors pay particular attention to disparity map construction approaches and improving the signal / noise ratio by a combination of known functions comparing the intensity of pixels: AD - a function of absolute differences, and Census function, comparing bit strings of investigated image regions.An important role in the noise minimization plays a simple, but effective assumption for aggregation, the gist of which is that pixels having similar intensity belong to the same structures in the image, and hence have a similar disparity. The variability of input parameters of the method and the ability to adjust the number of iterations provide accurate disparity maps for the input image of almost any quality (testing was conducted for webcams CBR CW 833M).The main result of this approach is the breathing profile based on the reconstructed depth maps, reflecting the respiration rate of the person under examination and presenting data on the amplitude variations of his chest.The main difference of the proposed method from other publications is a high accuracy and the breath profile calculation in real-time. It was achieved through OpenCL technology and parallel computations using the graphics card.The algorithm was tested on a variety of subjects with anthropomorphic characteristics and types of breathing to investigate the limited application of the proposed method in practice.DOI: 10.7463/mathm.0415.0813373Предложен новый метод для бесконтактного мониторинга параметров дыхания человека с помощью двух веб-камер, образующих стереопару. Метод базируется на анализе полученных изображений и использует алгоритмы компьютерного зрения. Предложен подход к построению карты диспаратности и улучшению соотношения сигнал/шум для анализируемых изображений. Основным результатом исследования является алгоритм выделения дыхательного профиля на основе карт глубин, полученных при обработке стереопары изображений. Основным отличием предложенного метода от известных является более высокая точность и возможность получения профиля дыхания в режиме реального времени. Приведен пример применения разработанного метода для оценки параметров дыхания человека.DOI: 10.7463/mathm.0415.081337

Exploring the Effects of the Presence or Absence of Sleep Architecture and Critically Ill Patient Outcomes

University of Minnesota Ph.D. dissertation. May 2019. Major: Nursing. Advisor: Ruth Lindquist. 1 computer file (PDF); ix, 123 pages.Abstract Background: Sleep disturbances and deprivation are known to exist in the critically ill patient. Over a 24-hour period, the critically ill can have 7-9 hours of sleep, but as much as 50% of that sleep can occur during daytime hours, signifying significant sleep fragmentation. Furthermore, some critically ill patients have been found to have abnormal brain waves that obliterate normal sleep architecture. These patients are without conventional sleep markers exhibiting no Stage II sleep spindles, minimal rapid eye movement sleep, and slow background brain wave reactivity. Disrupted sleep has been associated with delirium, weakened immune system, impaired wound healing, nitrogen imbalance, and negative cardiac, pulmonary, and neurological consequences which may all lead to negative patient outcomes. Objective: The objective of this dissertation was to explore factors and outcomes associated with sleep disturbances in critically ill patients. The state of knowledge related to sleep and delirium in critically ill patients were explored. The tools and challenges of measuring sleep in patients while in the intensive care unit (ICU) were also explored. Methods: Using a data base from retrospective chart review of 84 subjects, factors and outcomes related to the presence or absence of sleep in critically ill patients were explored. Literature reviews determined the state of knowledge related to sleep and delirium and the measurement of sleep in critically ill patients. Results. Severity of disease was significantly associated the absence of sleep architecture in both the continuous electroencephalogram (cEEG) 1 to 2- and 1 to 5-day groups. Propofol was significantly associated with the presence or absence of sleep architecture in the day 1-2 group. After adjusting for age and medications, serum creatinine and neurologic physiologic state during days 1 to 2 of cEEG are factors associated with no sleep architecture using bi-variate analysis. Multivariate logistic regression adjusting for age and medications during Days 1-2 cEEG found abnormal serum creatinine to be statically significant. After adjusting for age and medications, encephalopathy and developmental disability were factors significantly associated with no sleep architecture in the Day 1-5 group. . Multivariate logistic regression adjusting for age and medication during days 1-5 cEEG found the physiologic states of encephalopathy and developmental disability to be significantly associated with the absence of sleep architecture. The patient outcomes of increased mechanical ventilation days, ICU length of stay and hospital length of stay were associated significantly with no sleep architecture during Days 1-2 cEEG. In the 1-5 Days cEEG group, hospital length of stay was significantly associated with no sleep architecture. Post-hospitalization transfer location was associated with no sleep architecture for both cEEG groups. Discharge to home was associated with the presence of sleep architecture. Conclusions: Certain patient characteristics are associated with the presence or absence of sleep architecture. The presence or absence of sleep architecture may impact patient outcomes. The exploratory study indicates that future prospective research with larger sample sizes and sleep architecture specifics is needed to advance the state of knowledge. While delirium theoretically may be related to sleep disturbances, more research is needed to determine if a correlation exists. Measuring sleep architecture in ICU patients can be challenging. Critical illness can impact the reliability and accuracy of sleep measurement tools including the gold standard polysomnography. Researchers need to be clear in their research goals and know the challenges related to the various sleep measurement tools

Time for Quiet Reducing Nighttime Interruptions in the ICU (TURN IN-ICU): Evaluation and Implementation of a Nonpharmacological Sleep Bundle to Improve Sleep Quality, Delirium, and Nighttime Sedation Requirements

Background: Undisturbed, restful sleep is essential for physiological as well as psychological well-being. For critically ill patients, sleep deprivation caused by frequent nighttime interruptions is associated with poor sleep quality and negative patient outcomes. Objectives: The purpose of this Quality Improvement (QI) project was to promote uninterrupted sleep between the hours of 10 PM and 5 AM. Outcomes for evaluation consisted of the following three components: (1) sleep quality, (2) incidence of delirium, and (3) nighttime sedation requirements. Except for sleep quality, these variables were compared before and after the intervention. Methods: A descriptive, before and after design for data collection and analysis was utilized. Quantitative data was obtained via the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), and the Richards-Campbell Sleep Questionnaire (RCSQ). The nurse-driven, non-pharmacological ICU Sleep Checklist contained nine interventions reducing noise, light, and iatrogenic sleep disturbances. Results: Seventy-four patients received the intervention and completed the RCSQ. For all RCSQ items, patients scores indicated a tendency towards a favorable (mean, [SD], 51.78, [24.64]) and perceived nighttime noise levels were low (73.58, [26.93]. No incidences of ICU-acquired delirium were noted. A chi-square test determined a statistically significant relationship between CAM-ICU scores pre- and post-intervention (p Conclusions: We identified an association between people who report better sleep quality and those who receive less medications during the night. An improvement in the rate of ICU delirium in this population suggests that by promoting sleep, ICU nurses can prevent the onset of delirium. It is feasible to apply this intervention with a minimal amount of extra work for nurses. An improvement in the rate of ICU delirium in this population suggests that by promoting sleep, ICU nurses can prevent the onset of delirium

Optimizing Circadian Rhythm and Characterizing Brain Function in Disorders of Consciousness

Sleep is a physiological state where memory processing, learning and brain plasticity occur. Patients with prolonged disorders of consciousness (PDOC) show no or minimal signs of awareness of themselves or their environment but appear to have sleep-wake cycles. The main aim of this thesis was to investigate effect of circadian rhythm and sleep optimization on brain functions of patients with PDOC. In the first instance, sleep and circadian rhythms of patients with PDOC were investigated using polysomnography and saliva melatonin measurements. The investigations that were performed at the baseline suggested that both circadian rhythmicity and sleep were severely deranged in PDOC patients. This was followed by the interventional stage of the research where an attempt was made to optimize circadian rhythm and sleep by giving blue light, caffeine and melatonin in a small cohort of patients. To measure the effects of the intervention, we used a variety of assessments: Coma Recovery Scale-Revised (CRS-R) to measure changes in awareness; PSG for assessment of sleep, melatonin for assessment of circadian rhythm; and, event-related potential measures including mismatch negativity (MMN) and subject’s own name (SON) paradigms. Our results showed that it is possible to improve sleep and circadian rhythms of patients with PDOC, and most importantly, this improvement leads to increase in Coma Recovery Scale-Revised scores. Individually, those patients who responded well to the intervention also showed improvements in their functional brain imaging assessments

Sleep and Breathing in Preterm Infants : Polysomnography Studies on the Effects of Caffeine and Supplemental Oxygen

Sleep-disordered breathing in preterm infants is common and is a prominent issue in neonatal care. Preterm infants express breathing pauses called apneas, and periodic breathing (PB) consisting of repetitive intervals of short apneas and periods of hyperpnea. Apneas are commonly divided into central, obstructive, and mixed depending on the presence of absence of breathing effort. Central apneas show no airflow nor any breathing attempts. Obstructive apneas show breathing attempts in which airflow is restricted due to collapsed upper airways. Mixed apneas are a combination of these two, usually commencing as a central apnea, followed by obstructive breaths. In clinical neonatal practice, apneas are commonly not divided into central, obstructive, or mixed. Apneas in these infants are considered pathologic if they cause significant hypoxia, or bradycardia, or last for over 15 to 20 seconds. These respiratory pauses are called apnea of prematurity (AOP) irrespective of the presence or absence of upper airway obstruction. The use of the concept of AOP is not necessarily relevant as varying apnea types respond to different treatment methods. The significance of PB in preterm infants is disputed. PB causes intermittent hypoxia, which can, for example, lead to increased appearance of apneas and can impair preterm infants’ development. The approach of treatment depends on the degree of sleep-disordered breathing and on the treating center. Treatment modalities vary: invasive ventilatory support, high-flow nasal cannulas, continuous positive airway pressure, oxygen therapy, and methylxanthines such as caffeine or theophylline. In preterm infants, caffeine reduces the number of apneas and PB, and reduces the need for mechanical ventilation. It also promotes development. Supplemental oxygen stabilizes breathing and enhances oxygenation. Whereas the effect of supplemental oxygen is mediated through the peripheral chemoreceptors, the effect of caffeine as a breathing stimulant is most likely mediated through the stimulation of the central respiratory centers. Despite caffeine’s routine use in clinical practice, its effects on sleep and respiratory control in preterm infants are yet to be well established. Caffeine has a general stimulative effect on the central nervous system, and in adults and older children it increases alertness and prevents falling asleep; in preterm infants such an effect is not evident. Sleep in preterm infants differs significantly from sleep in older infants, children, and adults. Preterm infants spend most of their time asleep without any circadian rhythm. In contrast to later in life, their sleep is occupied by 40 to 60% of rapid-eye movement (REM) sleep compared, later in life, to around 15%. REM sleep is susceptible to disturbance, and in premature infants, respiratory disorders and intensive care with medical equipment and procedures interfere with sleep, especially with REM sleep. The development of sleep, sleep stages, and especially REM sleep are fundamental for normal development. Thus, knowledge about the effect of treatments on sleep in preterm infants is vital. This thesis study is based on polysomnographic data in late-preterm infants. We studied 21 preterm infants cared for in the neonatal wards of Helsinki University Hospital between 2013 and 2018. These infants were estimated by the pediatrician in charge of their care to need commencing of caffeine treatment for apneas or the presence of long periods of PB. We performed full polysomnography (PSG) studies in three phases: 1) at baseline prior to any intervention, 2) on supplemental oxygen, and 3) on the day after initiation of caffeine citrate treatment The analysis of the PSG studies comprised explicit sleep analysis, analysis of breathing disorders such as apneas and PB, arousals, and heart rate, and the effects of supplemental oxygen and of caffeine on these events. The results of this thesis study showed that sleep of preterm infants was fragmented by frequent arousal-type phenomena. Apneas seemed to have no disturbing effect on sleep and apneas rarely ended in an arousal from sleep. Therefore, apnea termination seems to be independent from arousal in preterm infants. Supplemental oxygen appeared to mildly increase arousal in response to AOP-defined apneas. Hypoxia did not effectively cause arousals in preterm infants. However, caffeine increased the rate of arousal in response to hypoxia. Caffeine and supplemental oxygen did not affect sleep, and despite acting as a respiratory stimulant, caffeine caused no notable central nervous system stimulation. The infants presented with long, AOP-defined apneas mainly in REM sleep, independent of their PB. These AOP-defined apneas were mostly of a mixed type with a considerably long central apnea before obstructive breathing efforts commenced, and they were to some degree affected by caffeine treatment. PB emerged as a state of mild hyperventilation, it appeared dominantly in non-REM sleep, and it caused intermittent hypoxia. Conventional oxygen saturation measurement with long averaging intervals may often miss this intermittent hypoxia. PB and subsequent intermittent hypoxia showed effective dampening with caffeine, and even greater dampening with supplemental oxygen. In conclusion, in preterm infants, sleep-disordered breathing consisted of PB in NREM sleep and long apneas either during falling asleep or in REM sleep. Long apneas were most often mixed apneas commencing as central apneas but continuing as upper airway obstruction. PB shared characteristics similar to those evident later in life. It appeared as a state of mild hyperventilation and responded both to supplemental oxygen and to caffeine. Caffeine did not appear to be a general central nervous system stimulant in preterm infants, which should further reassure us as to its use in such infants.Ennenaikaisesti syntyneillä lapsilla eli keskosilla unenaikaiset hengityshäiriöt ovat yleisiä ja ne ovat yksi keskosten hoidon keskeisistä ongelmista. Näitä hengityshäiriöitä ovat mm. hengityskatkokset eli apneat sekä jaksottainen eli periodien hengitys, joka koostuu toistuvista lyhyiden sentraalisen apneoiden ja niiden välissä olevien ylihengitysjaksojen sykleistä. Apneat jaetaan yleisesti sentraalisiin, tukoksellisiin (obstruktiivisiin) ja sekamuotoisiin sen perusteella, liittykö niihin hengitysyrityksiä vai ei. Kliinisessä käytännössä keskosilla ja vastasyntyneillä apneatyyppien jakoa ei tavanomaisesti tehdä. Heillä apneat arvioidaan merkittäviksi, jos niihin liittyy hapetustason tai syketason merkittävää laskua tai niiden kesto on yli 15–20 sekuntia. Kuitenkin eri apneatyyppien hoitoon tehoavat parhaiten eri hoitomenetelmät. Keskosilla esiintyvän jaksottaisen hengityksen merkitys on kiistelty ja sen normaalivaihtelua ei varmuudella tunneta. Jaksottaiseen hengitykseen on todettu liittyvän lyhyitä intermittoivia hapenpuutejaksoja. Tällaisen intermittoivan hapenpuutteen on todettu liittyvän keskosilla mm. apneoiden lisääntymiseen sekä heikompaan kehitykseen. Kuitenkin sen merkityksestä keskosten kehitykseen on eriäviä arvioita. Keskosten hengityshäiriöiden yleisiä hoitomuotoja ovat vaikeusasteen mukaan hengityskonehoito, ylipainehengityshoito, korkeavirtausviiksihoito, happihoito ja kofeiinilääkitys. Keskosilla kofeiini vähentää apneoiden määrää, tasoittaa hengitystä, vähentää hengityskonehoidon tarvetta sekä parantaa keskosten kehitystä. Myös lisähappi tasoittaa keskosten hengitystä. Lisähappi vaikuttaa hengitykseen perifeeristen hapen ja hiilidioksidin aistinelimen, karotiskerästen, toiminnan lamaamisen kautta. Kofeiini puolestaan tehostaa hengitystä ja sen vaikutus välittyy ilmeisesti pääosin keskushermoston hengityskeskusten kautta. Aikuisilla ja vanhemmilla lapsilla kofeiini aktivoi keskushermostoa ja lisää valvetta. Kofeiinin rutiininomaisesta käytöstä huolimatta tietomme sen vaikutuksista keskosten nukkumiseen ja unen laatuun on vähäistä. Keskoset nukkuvat suurimman osan ajastaan, ja heidän unestaan valtaosa on vilke- eli REM-unta. REM-uni on herkkä häiriintymään ja keskoskaudella hengityshäiriöt sekä tehohoito häiritsevät unta, etenkin REM-unta. Unen ja sen eri vaiheiden, etenkin REM-unen, häiriintyminen haittaa normaalia kehitystä. Siten tieto keskosilla käytettävien hoitojen vaikutuksesta uneen on tärkeää. Tämä väitöskirjatyö pohjautuu keskosilla tehtyihin laajoihin unitutkimuksiin (polysomnografia, PSG). Tutkimme HUS Helsingin Yliopistollisen sairaalan Jorvin ja Kätilöopiston sairaaloiden vastasyntyneiden osastoilla 21 keskosta vuosina 2013–2018. Näillä lapsilla oli todettu merkittäviä apneoita tai taipumus runsaaseen periodiseen hengitykseen, minkä vuoksi heille suunniteltiin kliinisin perustein kofeiinihoidon aloitusta. Teimme näille lapsille laajat unitutkimukset kolmessa vaiheessa: 1) lähtötilanteessa ennen interventiota, 2) lisähapen annon aikana ja 3) kofeiinihoidon aloittamista seuraavana päivänä. Rekisteröintien pohjalta arvioimme tutkittavien unta ja sen eri vaiheita, hengityshäiriöitä (apneoita ja jaksottaista hengitystä) ja niiden esiintymistä eri univaiheissa sekä lisähapen ja kofeiinin vaikutusta. Tämän väitöskirjatyön tulokset osoittavat, että keskoslasten uni oli toistuvien spontaanien havahtumisten vuoksi huomattavan paljon pirstaleisempaa kuin silminnähden arvioituna. Apneoilla ei näyttänyt olevan unta häiritsevää vaikutusta, ja apneat ja hapenpuutejaksot päättyivät harvoin havahtumiseen. Apneoiden päättyminen vaikuttaa olevan keskosilla havahtumisesta riippumatonta, mikä johtunee ensisijaisesti keskosille ominaisista alhaisista vasteista hapenpuutteeseen. Lisähappi vaikutti hieman lisäävän havahtumisia pidempiin apneoihin. Hapenpuute ei ollut tehokas herättäjä, mutta kofeiini lisäsi siihen havahtumista. Kofeiini ja lisähappi eivät vaikuttaneet uneen. Johtopäätöksenä toteamme, että vaikka kofeiini toimi hengitystä stimuloivana lääkkeenä, se ei aiheuttanut merkittävää keskushermoston stimulaatiota näillä keskosilla, mikä edelleen vahvistaa kofeiinin turvallisuutta keskosten hengityshäiriöiden hoidossa. Tutkituilla keskosilla esiintyi yksittäisiä pitkiä keskosten apneoiksi määriteltyjä apneoita (apnea of prematurity, AOP) pääosin REM-unen aikana, erillään jaksottaisesta hengityksestä. Nämä apneat olivat pääosin sekamuotoisia, mutta usein niiden obstruktiivista osiota edelsi pitkä sentraalisen apnean osio. Kofeiini vähensi hieman näitä sekamuotoisia apneoita. Periodinen hengitys näyttäytyi hyperventilaatiotilana ja esiintyi pääosin rauhallisessa (NREM) unessa, ollen samankaltaista kuin myöhemmällä iällä. Siihen liittyi säännönmukaisesti toistuvat hapenpuutejaksot. Nämä jaksot jäävät huomaamatta, jos veren happikyllästeisyyden mittalaitteessa (pulssioksimetri) käytetään kliinisessä käytössä tavanomaista, pitkää keskiarvoistusaikaa. Kofeiini ja erityisesti lisähappi vähensivät huomattavasti periodista hengitystä ja niihin liittyneitä hapenpuutejaksoja