Explanatory models in neonatal intensive care: a tutorial

Abstract

BackgroundAcute care providers intervening on fragile patients face many knowledge and information related challenges. Explanation based on causal chains of events has limitations when applied to complex physiological systems, and model-driven educational software may overwhelm the learner with information. We introduce a new concept and educational technology to facilitate understanding, reasoning, and communication in the clinical environment. The aim is to grasp complex physiology in a more intuitive way.Explanatory models (EM)An EM is a representation of relevant physiologic processes that provides insight into the relationships between therapeutic interventions and monitored variables, and their dependency on incidents and pathologies. We systematically analyze types of information incorporated into models and displayed in simulations and consider their explanatory relevance.Transposition of the great arteries (TGA)A conceptual model (diagram) of the normal neonatal cardiorespiratory system is adapted to reflect TGA and implemented in animated, interactive software.Illustration of educational useThe use of this model is illustrated via the explanation to pediatric residents of the relationships between blood pressures, blood flow rates, ventilation, oxygen saturation, and oxygen distribution in a neonate with TGA. Learners explore clinical scenarios and effects of therapeutic interventions.DiscussionExplanatory models hold promise as mental models for clinical practice and could possibly play a role in clinical decision making in neonatal intensive care and beyond.Companion softwareThe software is freely available via the web addendum: https://www.dropbox.com/sh/ciufq5rqxgs9bkt/AAC7oKsvkEr73eYUJkx0pZ1Ya?dl=0

Modeling renal autoregulation in a hemodynamic, first‐trimester gestational model

“…The whole‐body hemodynamic model used in this study is adapted from the lumped compartment model as proposed by van Meurs and Antonius in combination with the model proposed by Goodwin et al (Goodwin et al, 2004 ; van Meurs & Antonius, 2018 ). The model consists of “compartments” and “connectors”: compartments are defined as compliances containing volume, which, in turn, are combined by connectors that do not contain volume but can be described as resistances.…”

“…These include increased starting volume and increased volumes of RA, RV, LA, LV, and the compartments belonging to the kidneys and uterus as compared to the non‐pregnant condition (Cheung & Lafayette, 2013; Del Prado et al, 2020; Sanghavi & Rutherford, 2014; Song et al, 2015). Model parameters are based on prior studies (BioGears, 2018; Goodwin et al, 2004; van Meurs & Antonius, 2018) and were adjusted to reach gestational values. As from 4 to 8 weeks gestation, tremendous gestational changes and resetting of most systems already take place, the goal is to reach physiological hemodynamic values of an 8‐week pregnant condition, which are retrieved from original empirical data (Spaanderman et al, 2000).…”

“…Parameters are based on a woman with a body surface of 1.78 m 2 (BioGears, 2018 ; Goodwin et al, 2004 ; van Meurs & Antonius, 2018 ) Compartment V 0 (L) V (L) E (mmHg/L) PA 0.050 0.186 133 PV 0.350 0.460 64.5 LA * −0.005 0.047 138–360 LV * 0.014 0.121 77–3860 AA 0.068 0.135 1288 AD 0.175 0.333 539 UB 0.410 0.681 58.7 LB 1.614 2.295 23.3 AR 0.011 0.015 16,400 GL 0.020 0.027 1375 …”

“…Integrated mathematical models accounting for the whole‐body hemodynamic changes during pregnancy can help to simulate and better understand the interplay of underlying mechanisms of healthy and unhealthy cardiovascular adjustments and the subsequent effects on pregnancy outcomes (Euliano et al, 1997 ; Goodwin et al, 2004 ; van Meurs & Antonius, 2018 ). Our group works on a renal simulator implemented in a mathematical whole‐body circulatory environment.…”

Pressure and Flow Relations in the Systemic Arterial Tree Throughout Development From Newborn to Adult

“…To date, full-scale distributed models describe the adult circulation (2-7); an overview is given by Reymond et al (8). Descriptions of fetal (9, 10), neonatal (11), and infant (12) circulations do exist, however, usually with simplified arterial networks. Nevertheless, these models demonstrated clinical relevance.…”