Respiratory rate measurement in children using a thermal camera

Abstract— Respiratory rate is a vital physiological measurement used in the immediate assessment of unwell children. Con-venient electronic devices exist for measurement of pulse, blood pressure, oxygen saturation and temperature. Although de-vices which measure respiratory rate exist, none has entered everyday clinical practice. An accurate device which has no physical contact with the child is important to ensure readings are not affected by distress. A thermal imaging camera to moni-tor respiratory rate in children was evaluated. Facial thermal images of 20 children (age: median=6.5 years, range 6 months-17 years) were included in the study. Record-ings were performed while the children slept comfortably on a bed for a duration of two minutes. Values obtained using the thermal imaging camera were compared with those obtained from standard methods: nasal thermistor, respiratory impedance plethysmography and transcutaneous CO2. Median respiratory rate measurements per minute were 21.0 (range 15.5-34.0) using thermal imaging and 19.0 (range 15.3-34.0) using standard methods. A close correlation (r 2 = 0.994) was observed between the thermal imaging and the standard methods. The thermal imaging camera is an accurate, objective non-invasive device which can be used to measure respiratory rate in children

Modeling Decision Making In Trauma Centers From The Standpoint Of Complex Adaptive Systems

This research examines complex clinical decision-making processes in trauma center units of hospitals in terms of the impact of complexity on the medical team involved in the trauma event. The science of complex adaptive systems together with human judgment theories provide important concepts and tools for responding to health care challenges in this century and beyond. Clinical decision-makers in trauma centers are placed in urgent and anxious situations that are increasingly complex, making decision-making and problem-solving processes multifaceted. Under stressful circumstances, physicians must derive their decision-making schemas (―internal models‖ or ―mental models‖) without the benefits of judicious identification, evaluation, and/or application of relevant medical information, and always using fragmentary data. This research developed a model of decision-making processes in trauma events that uses a Bayesian Classifier model jointly with Convolution and Deconvolution operators to study real-time observed trauma data for decision-making processes under stress. The objective was to explore and explain physicians‘ decision-making processes during actual trauma events while under the stress of time constraints and lack of data. The research addresses important operations that describe the behavior of a dynamic system resulting from stress placed on the physician‘s rational decision making processes by the conditions of the environment. Deconvolution, that is, determining the impulse response of the system, is used to understand how physicians clear out extraneous environmental noise in order to have a clearer picture of their mental models and reach a diagnosis or diagnostic course of action

Acute lung injury in paediatric intensive care: course and outcome

Introduction: Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) carry a high morbidity and mortality (10-90%). ALI is characterised by non-cardiogenic pulmonary oedema and refractory hypoxaemia of multifactorial aetiology [1]. There is limited data about outcome particularly in children. Methods This retrospective cohort study of 85 randomly selected patients with respiratory failure recruited from a prospectively collected database represents 7.1% of 1187 admissions. They include those treated with High Frequency Oscillation Ventilation (HFOV). The patients were admitted between 1 November 1998 and 31 October 2000. Results: Of the 85, 49 developed acute lung injury and 47 had ARDS. There were 26 males and 23 females with a median age and weight of 7.7 months (range 1 day-12.8 years) and 8 kg (range 0.8-40 kg). There were 7 deaths giving a crude mortality of 14.3%, all of which fulfilled the Consensus I [1] criteria for ARDS. Pulmonary occlusion pressures were not routinely measured. The A-a gradient and PaO2/FiO2 ratio (median + [95% CI]) were 37.46 [31.82-43.1] kPa and 19.12 [15.26-22.98] kPa respectively. The non-survivors had a significantly lower PaO2/FiO2 ratio (13 [6.07-19.93] kPa) compared to survivors (23.85 [19.57-28.13] kPa) (P = 0.03) and had a higher A-a gradient (51.05 [35.68-66.42] kPa) compared to survivors (36.07 [30.2-41.94]) kPa though not significant (P = 0.06). Twenty-nine patients (59.2%) were oscillated (Sensormedics 3100A) including all 7 non-survivors. There was no difference in ventilation requirements for CMV prior to oscillation. Seventeen of the 49 (34.7%) were treated with Nitric Oxide including 5 out of 7 non-survivors (71.4%). The median (95% CI) number of failed organs was 3 (1.96-4.04) for non-survivors compared to 1 (0.62-1.62) for survivors (P = 0.03). There were 27 patients with isolated respiratory failure all of whom survived. Six (85.7%) of the non-survivors also required cardiovascular support.Conclusion: A crude mortality of 14.3% compares favourably to published data. The A-a gradient and PaO2/FiO2 ratio may be of help in morbidity scoring in paediatric ARDS. Use of Nitric Oxide and HFOV is associated with increased mortality, which probably relates to the severity of disease. Multiple organ failure particularly respiratory and cardiac disease is associated with increased mortality. ARDS with isolated respiratory failure carries a good prognosis in children

TeamSTEPPS Training and Vital Signs Chart to Improve Situational Monitoring for Clinical Deterioration

Failure to monitor early warning signs of patient deterioration can result in cardiopulmonary arrests and patient death. Implementation of team building programs emphasizing vital sign data, with consistent monitoring and trending have demonstrated positive outcomes in multiple health care environments. This project implemented TeamSTEPPS© education for 23 registered nurse (RN) residents in an acute care medical center. Specific aims included: (a) increased knowledge of team communication techniques; (b) improved attitudes towards vital sign monitoring, especially respiratory rate assessment; and (c) improved attitudes towards early rapid response system activation. The education program included support tools, behavioral-modeling, simulation exercises based on de-identified patient data and debriefing. Paired t-tests evaluated the impact of the intervention on total TeamSTEPPS Teamwork Attitudes Questionnaire (T-TAQ) and V-Scale scores. There were statistically significant increases in T-TAQ and V-Scale scores post intervention (1.78 p =.04 and 1.87 p = .04 respectively). Eta square calculation indicated a large effect size for T-TAQ and V-Scale measures. The TeamSTEPPS simulation-enhanced curriculum was successful in improving RN residents’ attitudes toward teamwork, and vital signs monitoring and surveillance practices

Masks and tubes used to support the neonatal airway – how to improve their fit, seal and correct placement

Despite the many changes in perinatal medicine in the last fifty years, infants still often and unpredictably need assistance with their breathing. Positive pressure delivered through a facemask remains the almost universal initial approach. This is then generally followed by endotracheal intubation if the infant is not responding or if prolonged support is needed. Despite many years of research into mask ventilation, it is still very challenging and leak and airway obstruction remain a problem. The thesis opens with two mask studies that try to solve this problem. The first is a manikin study that compared three different mask holds. It unfortunately found that there was no difference in the mask leak measured using the different holds. It is perhaps reasonable to change holds if the baby isn’t responding as expected. The second study aimed to measure the dimensions of preterm infants’ faces and compare these with the size of the most commonly available face masks. It found that the smallest size of some brands of mask is too large for many preterm infants. Masks of 35mm diameter are suitable for infants <29 weeks PMA or 1000g. Masks of 42 mm diameter are suitable for infants 27-33 weeks PMA or 750-2500g. The thesis then changed focus to neonatal intubation. Intubation is a challenging skill for paediatric trainees to master. In recent years success rates are decreasing. The next studies look at possible ways to change this trend. The first is a Cochrane review that examined if a stylet could improve intubation success. Only one unblended RCT has been performed and found no difference. The most sizable work of the thesis follows and is a RCT that examines if junior trainees intubation success rates are superior if they intubate with a videolaryngoscope. Two hundred and six intubations were randomised to the screen being visible to the supervisor or covered. The success rate when the instructor was able to view the videolaryngoscope screen was 66% (69/104) compared to 41% (42/102) when the screen was covered, (p<0.001), OR 2.81 (95%CI 1.54-5.17). This shows that videolaryngoscopy is a promising tool to help inexperienced trainees become proficient intubators. This study has resulted in videolaryngoscopy becoming a tool commonly used in neonatal intensive cares. The next study looks at recordings of unsuccessful intubations from the RCT. If an attempt is unsuccessful, the intubator and instructor often cannot explain why making it difficult to know what to do differently in the future. The study found that lack of intubation success was most commonly due to failure to recognize midline anatomical structures. Excessive secretions are rarely a factor in elective premeditated and routine suctioning should be discouraged. Better videolaryngoscope blade design may make it easier to direct the tube through the vocal cords. The final work of the thesis is a review that examines devices used during newborn stabilization. Evidence for their use to optimize the thermal, respiratory and cardiovascular management in the delivery room is presented. After completing all this work I think that perhaps it is time to lessen our reliance on facemasks and embrace other airway devices that are showing promise, particularly the laryngeal mask. I feel that universal intubation competency is no longer feasible but universal competency on the use of laryngeal masks probably is. This urgently needs to be addressed in paediatric training programs. Videolaryngoscopy is a promising tool that improves junior intubators’ success rates. To master intubation many intubations are still necessary but the videolaryngoscope allows the slope of the learning curve to steepen. Development is necessary to design scopes of the future that are inexpensive, easily portable and user friendly

An investigation into the effects of commencing haemodialysis in the critically ill

&lt;b&gt;Introduction:&lt;/b&gt; We have aimed to describe haemodynamic changes when haemodialysis is instituted in the critically ill. 3 hypotheses are tested: 1)The initial session is associated with cardiovascular instability, 2)The initial session is associated with more cardiovascular instability compared to subsequent sessions, and 3)Looking at unstable sessions alone, there will be a greater proportion of potentially harmful changes in the initial sessions compared to subsequent ones. &lt;b&gt;Methods:&lt;/b&gt; Data was collected for 209 patients, identifying 1605 dialysis sessions. Analysis was performed on hourly records, classifying sessions as stable/unstable by a cutoff of &gt;+/-20% change in baseline physiology (HR/MAP). Data from 3 hours prior, and 4 hours after dialysis was included, and average and minimum values derived. 3 time comparisons were made (pre-HD:during, during HD:post, pre-HD:post). Initial sessions were analysed separately from subsequent sessions to derive 2 groups. If a session was identified as being unstable, then the nature of instability was examined by recording whether changes crossed defined physiological ranges. The changes seen in unstable sessions could be described as to their effects: being harmful/potentially harmful, or beneficial/potentially beneficial. &lt;b&gt;Results:&lt;/b&gt; Discarding incomplete data, 181 initial and 1382 subsequent sessions were analysed. A session was deemed to be stable if there was no significant change (&gt;+/-20%) in the time-averaged or minimum MAP/HR across time comparisons. By this definition 85/181 initial sessions were unstable (47%, 95% CI SEM 39.8-54.2). Therefore Hypothesis 1 is accepted. This compares to 44% of subsequent sessions (95% CI 41.1-46.3). Comparing these proportions and their respective CI gives a 95% CI for the standard error of the difference of -4% to 10%. Therefore Hypothesis 2 is rejected. In initial sessions there were 92/1020 harmful changes. This gives a proportion of 9.0% (95% CI SEM 7.4-10.9). In the subsequent sessions there were 712/7248 harmful changes. This gives a proportion of 9.8% (95% CI SEM 9.1-10.5). Comparing the two unpaired proportions gives a difference of -0.08% with a 95% CI of the SE of the difference of -2.5 to +1.2. Hypothesis 3 is rejected. Fisher’s exact test gives a result of p=0.68, reinforcing the lack of significant variance. &lt;b&gt;Conclusions:&lt;/b&gt; Our results reject the claims that using haemodialysis is an inherently unstable choice of therapy. Although proportionally more of the initial sessions are classed as unstable, the majority of MAP and HR changes are beneficial in nature

An impedance pneumography signal quality index: Design, assessment and application to respiratory rate monitoring.

Impedance pneumography (ImP) is widely used for respiratory rate (RR) monitoring. However, ImP-derived RRs can be imprecise. The aim of this study was to develop a signal quality index (SQI) for the ImP signal, and couple it with a RR algorithm, to improve RR monitoring. An SQI was designed which identifies candidate breaths and assesses signal quality using: the variation in detected breath durations, how well peaks and troughs are defined, and the similarity of breath morphologies. The SQI categorises 32 s signal segments as either high or low quality. Its performance was evaluated using two critical care datasets. RRs were estimated from high-quality segments using a RR algorithm, and compared with reference RRs derived from manual annotations. The SQI had a sensitivity of 77.7 %, and specificity of 82.3 %. RRs estimated from segments classified as high quality were accurate and precise, with mean absolute errors of 0.21 and 0.40 breaths per minute (bpm) on the two datasets. Clinical monitor RRs were significantly less precise. The SQI classified 34.9 % of real-world data as high quality. In conclusion, the proposed SQI accurately identifies high-quality segments, and RRs estimated from those segments are precise enough for clinical decision making. This SQI may improve RR monitoring in critical care. Further work should assess it with wearable sensor data.This work was supported by a UK Engineering and Physical Sciences Research Council (EPSRC) Impact Acceleration Award awarded to PHC; the EPSRC [EP/H019944/1]; the Wellcome EPSRC Centre for Medical Engineering at King’s College London [WT 203148/Z/16/Z]; the Oxford and King’s College London Centres of Excellence in Medical Engineering funded by the Wellcome Trust and EPSRC under grants [WT88877/Z/09/Z] and [WT088641/Z/09/Z]; the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s & St Thomas’ NHS Foundation Trust and King’s College London; the NIHR Oxford Biomedical Research Centre Programme; a Royal Academy of Engineering Research Fellowship (RAEng) awarded to DAC; and EPSRC grants EP/P009824/1 and EP/N020774/1 to DAC

Advanced analyses of physiological signals and their role in Neonatal Intensive Care

Preterm infants admitted to the neonatal intensive care unit (NICU) face an array of life-threatening diseases requiring procedures such as resuscitation and invasive monitoring, and other risks related to exposure to the hospital environment, all of which may have lifelong implications. This thesis examined a range of applications for advanced signal analyses in the NICU, from identifying of physiological patterns associated with neonatal outcomes, to evaluating the impact of certain treatments on physiological variability. Firstly, the thesis examined the potential to identify infants at risk of developing intraventricular haemorrhage, often interrelated with factors leading to preterm birth, mechanical ventilation, hypoxia and prolonged apnoeas. This thesis then characterised the cardiovascular impact of caffeine therapy which is often administered to prevent and treat apnoea of prematurity, finding greater pulse pressure variability and enhanced responsiveness of the autonomic nervous system. Cerebral autoregulation maintains cerebral blood flow despite fluctuations in arterial blood pressure and is an important consideration for preterm infants who are especially vulnerable to brain injury. Using various time and frequency domain correlation techniques, the thesis found acute changes in cerebral autoregulation of preterm infants following caffeine therapy. Nutrition in early life may also affect neurodevelopment and morbidity in later life. This thesis developed models for identifying malnutrition risk using anthropometry and near-infrared interactance features. This thesis has presented a range of ways in which advanced analyses including time series analysis, feature selection and model development can be applied to neonatal intensive care. There is a clear role for such analyses in early detection of clinical outcomes, characterising the effects of relevant treatments or pathologies and identifying infants at risk of later morbidity

Wearable continuous vital sign monitoring for deterioration detection and clinical outcomes in hospitalised patients

 Current practice uses physiological early warning scoring (EWS) systems to monitor “standard” vital signs, including heart rate (HR), respiratory rate (RR), blood pressure (BP), oxygen saturations (SpO2) and temperature, coupled with a graded response such as referral for a senior review or increasing monitoring frequency. Early detection of the deteriorating patient is a known challenge within hospital environments, as EWS is dependent on correct frequency of physiological observations tailored to specific patient needs, that can be time consuming for healthcare professionals, resulting in missed or incomplete observations. Wearable monitoring systems (WMS) may bring the potential to fill the gap in vital sign monitoring between traditional intermittent manual measurements and continuous automatic monitoring. However, evidence on the feasibility and impact of WMS implementation remains scarce. The virtual High Dependency Unit (vHDU) project was designed to develop and test the feasibility of deploying a WMS system in the hospital ward environment. This doctoral work aims to critically analyse the roadmap work of the vHDU project, containing ten publications distributed throughout 7 chapters. Chapter 1 (with 3 publications) includes a systematic review and meta-analysis identifying the lack of statistical evidence of the impact of WMS in early deterioration detection and associated clinical outcomes, highlighting the need for high-quality randomised controlled trials (RCTs). It also supports the use of WMS as a complement, and not a substitute, for standard and direct care. Chapter 2 explores clinical staff and patient perceptions of current vital sign monitoring practices, as well as their early thoughts on the use of WMS in the hospital environment through a qualitative interview study. WMS were seen positively by both clinical and patient groups as a potential tool to bridge the gap between manual observations and the traditional wired continuous automatic systems, as long as it does not add more noise to the wards nor replaces direct contact from the clinical staff. In chapter 3, the wearability of 7 commercially available wearables (monitoring HR, RR and SpO2) was assessed, advocating for the use of pulse oximeters without a fingertip probe and a small chest patch to improve worn times from the patients. Out of these, five devices were submitted to measurement accuracy testing (chapter 4, with 3 publications) under movement and controlled hypoxaemia, resulting in the validation of a chest patch (monitoring HR and RR) and proving the diagnostic accuracy of 3 pulse oximeters (monitoring pulse rate, PR and SpO2) under test. These results were timely for the final selection of the devices to be integrated in our WMS, namely vHDU system, explored in chapter 5, outlining the process for its development and rapid deployment in COVID-19 isolation wards in our local hospital during the pandemic. This work is now converging in the design of a feasibility RCT to test the impact of the vHDU system (now augmented with blood pressure and temperature monitoring, completing all 5 vital signs) versus standard care in an unbiased environment (chapter 6). This will also ascertain the feasibility for a multicentre RCT, that may in the future, contribute with the much-needed statistical evidence to my systematic review and meta-analysis research question, highlighted in chapter 1. Finally, chapter 7 includes a critical reflection of the vHDU project and overall doctoral work, as well as its contributions to the field of wearable monitoring.<p class="MsoNormal"/

Effects of Ubiquinol with Fluid Resuscitation following Hemorrhagic Shock

Abstract Hemorrhagic shock (HS) and fluid resuscitation triggers ischemia-reperfusion injury in cells and increases the production of reactive oxygen species (ROS) which are known to activate the intrinsic pathway of apoptosis and contribute to organ dysfunction.1 Ubiquinol is a potent free radical scavenger which is produced endogenously and functions as part of the mitochondrial respiratory chain.2 No study has been conducted to investigate the effects of ubiquinol related to HS. The overall aim of this study was to examine the effects of ubiquinol on leukocyte mitochondria and in the lungs, diaphragm, heart and kidneys as a supplemental treatment for HS. A randomized experimental design was used for this study. Adult male Sprague-Dawley rats (n = 20) were anesthetized and HS was induced by withdrawing 40% of the rat's blood volume to maintain a mean arterial pressure of 45-55 mmHg for 60 minutes. Following HS the rats were resuscitated with blood and lactated Ringer's (LR) with or without ubiquinol (1 mg per 100 g of body weight). The rats were monitored for 120 minutes, the animals were euthanized and the organs harvested. Leukocyte mitochondria superoxide (O2*⁻) was measured by flow cytometry using MitoSOX Red, a mitochondrial-targeted variant of the fluorescent probe hydroethidine. Superoxide levels were measured at baseline, end of HS and 120 minutes following fluid resuscitation. Arterial blood values were also recorded at these times. At the end of experiment, diaphragms were evaluated for hydrogen peroxide (H2O2) using the fluorescent probe dihydrofluorescein-diacetate (Hfluor). The lungs, diaphragm, heart, and kidneys were examined for percent of apoptotic nuclear membrane damage using a differential dye uptake method with acridine orange and ethidium bromide. No significant differences were found between groups with regard to the volume of blood removed, hemodynamic status or arterial blood values (p 0.05). Ubiquinol decreased leukocyte mitochondrial production of O2*⁻ at the end of the experiment by 35% compared to the control group (4687.2 ± 265.4 versus 7227.9 ± 534.5, p ˂ 0.001). Similarly, the mean fluorescence intensity (MFI) of diaphragm H2O2 was significantly lower in the ubiquinol group compared to control (4193 ± 333 versus 23513 ± 5098, p ˂ 0.001). The percent of apoptosis in the lungs, diaphragm, heart, and kidneys was significantly reduced in the animals treated with ubiquinol compared to the control group (6.0 ± 0.7% versus 39.2 ± 1.1%, 4.7 ± 0.5% versus 30.6 ± 2.4%, 2.9 ± 0.6% versus 23.6 ± 1.2%, 2.4 ± 0.3% versus 42.1± 1.9%, respectively, p ˂ 0.001). Ubiquinol was effective in decreasing leukocyte mitochondrial O2*⁻ formation, which suggests that ubiquinol scavenged O2*⁻ within the mitochondria. Since ubiquinol is a potent antioxidant, it also probably scavenged other free radicals outside the mitochondria. The increased concentration of ubiquinol within the mitochondria would assist in maintaining the activities within the electron transport chain during HS. In addition, the decreased mitochondrial O2*⁻ would result in lower H2O2 production. The significant reduction in the percent of apoptosis in lungs, diaphragm, heart and kidneys between the control and treatment rats, suggests that decreased ROS production attenuated the activation of the intrinsic (mitochondrial) apoptosis pathway.3 The findings could also be attributed to the stabilization of the mitochondrial membrane by ubiquinol, which has been demonstrated in a previous study.4 In conclusion, ubiquinol may have application as a supplemental treatment to reduce free radical damage and apoptosis- related injury following HS and fluid resuscitation