Non-invasive Monitoring of hemodynamic status in preterm infants:a prospective comparison of 3 different approaches including feasibility, reproducibility and association to relevant clinical short term outcome

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Background:Understanding neonatal hemodynamics is key to neonatal care and neuroprotection. Despite decades of research, uncertainty continues as to how to continuously monitor hemodynamics in extremely preterm infants. Blood flow is mainly dependent on two key factors: blood pressure (BP) and vascular resistance (and the presence of neonatal shunts). It is still common practice to focus only on BP, thus neglecting the complex and dynamic (patho)physiology that may be present in newborn infants. Thus, in infants with low blood pressure, flow (and hence oxygen delivery) or its surrogate parameter cardiac output, can still be normal in cases of low systemic vascular resistance. Non-invasive cardiac output (CO) monitoring, cerebral regional oxygenation (Near-infrared spectroscopy, NIRS) and pulsatility index monitoring (PI, pulse oxymetry) may have the potential to support routine hemodynamic monitoring of BP and heart rate with additional information.Methods: We intend to perform a prospective observational trial in 100 preterm infants born at Cork University Maternity Hospital (birth rate of almost 8000 babies in 2016) <32 weeks’ gestation during the first 48 postnatal hours. This study consists of 2 parts:1. feasibility and reproducibility: to ensure CO monitoring using electrical cardiometry (Osypka Medical, Berlin, Germany) is safe and reliable (20 infants).2. (main study) prediction of circulatory failure by non-invasive hemodynamic monitoring (80 additional infants).Outcome Variables:For feasibility:The proportion of infants in whom a continuous recording of CO by electrical cardiometry and PI analysis was obtained for at least 24 hours during the first 48 hours after birth.For reproducibility:CO-monitoring and echocardiography (i.e. left ventricular output).Main study: Prediction of circulatory failureDependent variable: Adverse outcome (Yes/No), where an adverse outcome is defined as a cranial ultrasound abnormality or death within 7 days of birth.Independent variables: Onset and proportion of time infants are suspected to have impaired hemodynamics as defined by clinical suspicion (i.e. skin colour, capillary refill time>3s), laboratory parameters (i.e. lactic acidosis), BP, PI analysis, NIRS or CO measures and combination of these measures.Aim:The principle objective of this study is to determine the impact of different continuous hemodynamic monitoring methods and to establish non-invasive hemodynamic monitoring methods in preterm infants within 48 hours of birth. These data may result in more precise definitions of arterial hypotension and permissive hypotension, thus providing data for an evidence based algorithm to assess hemodynamic status in preterm infants.