Fluid Responsiveness Prediction During Prone Position
Acute Respiratory Distress SyndromePredicting fluid responsiveness is primordial when caring for patients with circulatory shock as it allows correction of preload-dependent low cardiac output states, while preserving patients of the deleterious effects of excessive fluid resuscitation. Patients with severe acute respiratory distress syndrome (ARDS) treated with prone positioning (PP) are a specific subset of patients, as 1) they frequently present with shock; 2) excessive fluid administration may lead to respiratory worsening due to increased hydrostatic oedema with potential subsequent worse clinical outcome; and 3) all available dynamic tests evaluating fluid responsiveness can only be performed in patients in the supine condition (which in the case of severe ARDS patients in PP occurs only for 8h over 24h). These elements warrant the development of specific tests allowing the clinician to predict fluid responsiveness with enough exactitude when caring for these patients. We hypothesize that there exists diagnostic heterogeneity in the predictive performance of 4 clinical tests to identify fluid responsiveness in ARDS patients in PP. For the matter of this study, these 4 tests are the Trendelenburg maneuver, the end-expiratory occlusion test, the end-expiratory occlusion test associated with the end-inspiratory occlusion test, and the tidal volume challenge. The diagnostic reference of the study will be the relative change in cardiac index measured by transpulmonary thermodilution before and after a 500 ml fluid bolus, and will allow the adjudication of patients as being fluid responsive or not. The primary objective of the study is to determine the area under the ROC curve of each of the 4 tests, with their respective 95% confidence interval. All enrolled patients will perform the 4 tests following a cross-over design and in a randomized sequence, separated by 1-min wash-out periods with return to hemodynamic baseline values, and concluded with the 500-ml fluid bolus. Patients will only participate once. The expected duration of study participation is 30 minutes maximum.
Measuring Diaphragm Electrical Activity in Neonates Using a Smaller Inter-electrode Distance
Respiratory Distress SyndromeNewborn2 moreNeurally Adjusted Ventilatory Assist (NAVA) is a mode of ventilation where the electrical activity of the diaphragm (EDI) - a signal representing the baby's respiratory drive - is used to control the timing and amount of assist provided. NAVA was introduced to the market in 2007 and since has been used in more than 40 countries. In the current clinical practice, the Edi signal from the patient is captured with miniature sensors (the size of a hair) embedded in the wall of a specially designed naso/orogastric feeding tube. This FDA and Health Canada approved, commercially available catheter (Getinge, Solna, Sweden), is 6 Fr in size (outer diameter), 49 cm in length and has 8 pairs of sensors that are placed 6 mm apart (so-called inter electrode distance (IED) is 6 mm). While no obvious side effects have been noted by clinicians, for the smallest of neonates, the currently used commercial catheter (size 6F, 49 cm long) may have 'excessive' post-array catheter length. In these neonates, typically those with weight < 750 grams, following the correct placement of catheter as per the electrode array positioning at gastro-esophageal junction, the feeding holes in the catheter may end at the level of distal stomach instead of the desirable mid-stomach location. The changing demographics of the patients in the Neonatal Intensive Care Units (NICU) has created a clinical need to redesign the currently used Edi catheter specifically to suit the smallest of patients, such that following adequate placement the feeding holes sit at the level of mid-stomach. Drs. Christer Sinderby and Jennifer Beck in Toronto, Canada, are the original designers of the 6 mm/49 cm currently used Edi catheter. These investigators (at St-Michael's Hospital, Toronto) in collaboration with their team at Neurovent Research Inc. (NVR) have re-designed and invented a new prototype of the current FDA-approved catheter specifically suited for use in extreme premature neonates. They have done so by reducing the interelectrode distance from the originally set 6 mm to 4 mm, which reduces the overall insertion depth to capture the same signal from the diaphragm. All other parameters are exactly same as the original catheter (6F, 49 cm long). In this small feasibility study the investigators wish to provide a clinical proof of concept for the use of this newly designed prototype in 10 extremely premature neonates who are already receiving NAVA ventilation in the NICU.
Evaluation of the Impact of SpO2 Averaging Time on Performance of an Automatic FiO2 Control System:...
Neonatal Respiratory DistressVery Low Birth Weight InfantThe aim of the study is to determine the preferred oximeter averaging setting during automated control of FiO2 (A-FiO2) in infants receiving respiratory support and supplemental oxygen.
The Use of Sedation Drugs in the Procedure of Administering Surfactant Without Intubation (LISA/MIST)...
Neonatal Respiratory Distress SyndromeGestational Age ConditionsThe purpose of this study is to evaluate the efficacy and impact of intravenous ketamine or sublingual 30% glucose as sedation drugs used in preterm premature babies during the LISA procedure. The second goal is to compare the frequency of complications during LISA with both premedication regimens.
Influence of NEP Inhibition on Vascular Leak and Inflammation (NEPi-INFLAMMATION)
Acute Respiratory Distress SyndromeAcute Respiratory Distress Syndrome (ARDS) is a severe type of lung injury that affects 10% of patients admitted to Intensive Care Units worldwide, with an unacceptably high mortality of up to 48% in those with the most severe form of the condition. It is a complex and poorly understood syndrome that results in progressive failure of the lungs. Crucially, the inflamed lungs allow fluid to leak from the circulation into the airspace, so that patients' lungs fill with fluid - "drowning from the inside". As this condition progresses, the patient typically requires increasing amounts of oxygen and eventually, support from a ventilator. To date, there are no effective treatments for ARDS that can limit, stop or repair this process. This research study is aiming to look at a naturally occurring substance produced by blood vessels, C-type natriuretic peptide (CNP). The investigators have evidence suggesting that CNP plays a role in maintaining the barrier provided by blood vessels that stops fluid leaking out into tissues. This is based on various studies done on CNP by the investigators research group that have established its widespread role in maintaining cells that line blood vessels and play a vital role in lungs' barrier function: the endothelium. CNP is broken down in part by an enzyme called Neutral endopeptidase and therefore, drugs that inhibit this enzyme would result in increased CNP concentration and activity. If CNP does in fact strengthen the lungs' endothelial barrier, then this class of drug may benefit patients with ARDS. The aim of this experimental medicine study is to assess the effect of using the licensed NEP inhibitor Racecadotril, in a well-established, safe model of inflammation-induced skin blisters in healthy human volunteers to determine primarily whether the fluid accumulation i.e. leak, in these blisters is reduced by treatment with this drug.
REcruitment MAneuvers and Mechanical Ventilation Guided by EIT in pARDS
ARDSPediatric Respiratory Distress Syndrome1 moreThere is evidence from randomized controlled trials in adult patients with Acute Respiratory Distress Syndrome (ARDS) suggesting that delivering small tidal volumes with adequate levels of Positive End-Expiratory Pressure (PEEP) and a restrictive fluid strategy could improve outcome. However, there are data and common bedside experience that individual patients may or may not respond to interventions, such as escalation of PEEP or positional changes, and there may be a role for a more personalized ventilator strategy. This strategy could account for the unique individual morphology of lung disease, such as the amount of atelectasis and overdistension as a percentage of total lung tissue, the exact location of atelectasis, and whether positional changes or elevation of PEEP produce lung recruitment or overdistension. Stepwise Recruitment maneuvers (SRMs) in pARDS improve oxygenation in majority of patients. SRMs should be considered for use on an individualized basis in patients with pARDS should be considered if SpO2 decreases by ≥ 5% within 5 minutes of disconnection during suction or coughing or agitation. If a recruitment maneuver is conducted, a decremental PEEP trial must be done to determine the minimum PEEP that sustains the benefits of the recruitment maneuver. Electrical impedance tomography (EIT), a bedside monitor to describe regional lung volume changes, displays a real-time cross-sectional image of the lung. EIT is a non-invasive, non-operator dependent, bedside, radiations-free diagnostic tool, feasible in paediatric patients and repeatable. It allows to study ventilation distribution dividing lungs in four Region Of Interest (ROI), that are layers distributed in an anteroposterior direction, and shows how ventilation is distributed in the areas concerned. EIT measures and calculates other parameters that are related not only to the distribution of ventilation, but also to the homogeneity of ventilation and the response to certain therapeutic maneuvers, such as SRMs or PEEP-application. Aim of this study is to provide a protocolized strategy to assess optimal recruitment and PEEP setting, tailored on the patients individual response in pARDS.
Use of Gentle Synchronized Negative Pressure in Helping Babies Breathe
Respiratory Distress SyndromeTTN3 moreThe NeoVest delivery device is a wearable vest/shell that surrounds the infant's abdomen. It was developed using serial body measurements of infants previously admitted to the St. Michael's Hospital NICU (REB #15-183). It gently pulls on the abdomen by applying negative pressure, thereby displacing the diaphragm. The materials used for the NeoVest are lightweight and suitable for the infants' sensitive skin. The AIM of the present study is to demonstrate the feasibility of applying negative pressure NIV, that is synchronized and proportional to the infant's respiratory demand. The preliminary data on feasibility can be used to apply for larger grants from the CIHR, for a study of the NeoVest in smaller premature infants.
Clinical Decision Support for Mechanical Ventilation of Patients With ARDS
Acute Respiratory Distress SyndromePerform a pilot study of quality improvement interventions for critical care physicians (intensivists) and respiratory therapists (RTs) to improve application of low tidal volume mechanical ventilation (LTVV) for patients with the acute respiratory distress syndrome (ARDS) using the computerized mechanical ventilation protocols currently available in the investigator's Cerner electronic health record (EHR).
Ventilatory Strategy Based on Ultrasound Lung Morphology in Patients With Focal ARDS
Focal Acute Respiratory Distress SyndromeARDS is characterized by a diffuse, bilateral, extensive alveolar-interstitial infiltrate related to damage to the alveolar membrane. Studies of lung morphology assessed by CT scan have shown 2 types of ARDS. When the loss of ventilation is posterior and caudal, and the pulmonary parenchyma is otherwise "healthy", ARDS is said to be focal. When the loss of ventilation is diffuse, associated with excess tissue affecting the entire lung parenchyma, ARDS is said to be non-focal or diffuse. Only one recent multicenter study has evaluated whether individualized PEEP adjustment according to lung morphology (focal vs. non-focal) could improve ARDS survival outcomes compared with standard of care. Results for the primary endpoint, 90-day mortality, were negative. But lung morphology was misclassified on CT occurred 85 (21%) of 400 patients. In addition, per-protocol analysis in which misclassified patients were excluded showed that mortality was significantly lower in the personalized ventilation group than in the control group. Lung ultrasound may be the ideal bedside imaging technique. The loss of pulmonary aeration and its variations induced by therapeutic maneuvers can be quantified by lung ultrasound. Lung ultrasound is a non-invasive, non-ionizing radiation method that can be easily used at the bedside. APRV ventilation coupled with spontaneous breathing activity prevents atelectasis formation, recruits less ventilated areas, prevents mechanical ventilation-induced lung injury and improves lung compliance. The hypothesis is that a "LUVS" ventilatory strategy composed of a bundle of measures all aiming at reopening the atelectatic pulmonary zones in focal ARDS (synergistic effect of spontaneous ventilation in APRV mode, early prone sessions, and adjustment of PEEP according to the patient's BMI), could decrease the number of days under mechanical ventilation, compared to protective ventilation with low tidal volume according to the current international recommendations
Assessment of Cardiac Output in Patients With ARDS Implanted With Venous-venous ECMO.
Acute Respiratory Distress SyndromeIn patients with severe acute respiratory distress syndrome, extracorporeal membrane oxygenation (ECMO), which also as known as extracorporeal life support, may be used. This technique helps the lungs by providing oxygenation to the blood via an external gas exchanger and thus participates partially or fully in gas exchange. The ECMO device includes a pump for draining and returning blood at a certain blood flow rate (ECMO blood flow). An ECMO rate that is adapted to the patient's cardiac output (CO) is essential for effective oxygenation for patients. The objective for clinicians is an ECMO blood flow to cardiac output ≥40%, which can go up to 100% as needed. In addition to the expected benefit in the management of the patient with ARDS, measuring CO is, therefore, all the more important in patients requiring ECMO. Monitoring CO in a patient with ECMO is not only for determining the minimum ECMO blood flow rate but also for optimizing the functioning of the ECMO. However, the validity of techniques for measuring CO in patients with ECMO has been poorly studied. The reliability of the CO measurement by transpulmonary thermodilution is questioned since the extracorporeal circulation may influence the pathway of cold indicator injected into the patients' circulation and the thermodilution curve measured from the femoral arterial is thereby modified.