Transcutaneous Microcirculatory Imaging in Preterm Neonates

Summary

Microcirculatory imaging (MI) is used to monitor peripheral perfusion in critically ill or preterm neonates. This manuscript and video demonstrates the optimal approach for obtaining high-quality images.

Abstract

Microcirculatory imaging (MI) is a relatively new research tool mainly used in the intensive care setting. MI provides a clear view of the smallest capillaries, arterioles and venules. The magnifying effect visualizes the flow pattern of erythrocytes through these vessels.

It's non-invasive character makes it suitable to apply in (preterm) neonates, even in cardiorespiratory unstable patients. In adults and children, MI is mainly performed sublingually, but this is not possible in preterm infants as these cannot cooperate and the size of the probe is problematic. In preterm infants, MI is therefore performed transcutaneously. Their thin skin makes it possible to obtain high quality images of peripheral microcirculation.

In this manuscript we will demonstrate the method of transcutaneous MI in preterm infants. We will focus on the different techniques and provide tips to optimize image quality. The highlights of software settings, safety and offline analysis are also addressed.

Introduction

Hemodynamic diagnostics in critically ill preterm neonates has always been difficult. Most diagnostic tools used in adults cannot be applied in these tiny preterm infants; and then there is a problem of the sensitivity of the outcome parameters. But most of all, these infants are so vulnerable, that the risks of diagnostic procedures do not outweigh the benefits. As a result, in the field of neonatology, hemodynamics has been neglected and therefore there is a lack of knowledge on this topic.

An interesting option for handling these problems might be visualizing the microcirculation. The introduction of handheld microscopes in the late 1990....

Protocol

This protocol follows the guidelines of the local human research ethics committee.

1. Preparation

1. Schedule the microcirculatory measurement so that it does not coincide with other procedures such as blood sampling. In term neonates it is best performed after feeding. This prevents agitation and will ease the measurement.
2. Ensure that a nurse or a parent attends to support and comfort the neonate during the examination, using the principles of Newborn Individualized Developmental Care and Assessment Program¹².
   Note: Although measurements can be performed by a single person, it is highly recommended to h....

Results

Figures 1 and 2 show representative still images of high-quality MI videos. These examples demonstrate the difference in skin thickness in the same infants between day 1 (Figure 1) and day 28 (Figure 2) of postnatal age. On day 1, there is a bright illumination, adequate focus on the micro vessels and minimal presence of artefacts. On day 28 it is more difficult to find the right balance between focus on the micro vessels and artefacts du.......

Discussion

In this manuscript we describe and demonstrate the approach for transcutaneous microcirculatory imaging in preterm neonates. Visualizing this method will help researchers overcome two of the biggest challenges in research: reproducibility and the time and labor intensive nature of learning new techniques. This technique can provide useful information of peripheral microcirculation in preterm infants in a non-invasive manner. Serial measurements can help clinicians evaluate the effects of therapeutic interventions. The mi.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Cytocam	Braedius	http://www.braedius.com/magnoliaPublic/braedius/products.html	Other well known handheld microscopes to visualize the microcirculation are MicroScan (Microvision Medical) using SDF technique or the CytoScan (CytoMetrics) using OPS technique
Disposable Lens Cover	Glycocheck	http://www.glycocheck.com/lenscovers.php
CCTools	Braedius	http://www.braedius.com/magnoliaPublic/braedius/products.html	Another well known offline analysis programme is AVA (Microvision medical).