Estimation of the inspiratory effort in mechanical ventilated children in the pediatric intensive care unit

Mechanical ventilation (MV) is a life saving intervention in patients with
acute respiratory failure. Unfortunately, full ventilator support rapidly
induces diaphragm muscle fiber injury and atrophy, the main muscle for
inspiration, and is commonly referred to as ventilator-induced diaphragm
dysfunction (VIDD). To limit the risk of VIDD, clinicians use ventilator modes
that allow patients to perform at least part of the total work of breathing
when deemed clinically appropriate. In clinical practice, it would be important
to quantify the amount of inspiratory pressure generated by the patient and the
level of unloading provided by the ventilator in order to prevent ventilator
under- or over-assistance. The gold standard reference for the measurement of
the pressure developed by respiratory muscles (Pmus) is based on esophageal
pressure (Pes) measurement, but this technique is rather complex and prone to
errors. In this study two less invasive diagnostic techniques, electrical
activity of the diaphragm and ultrasound of the diaphragm, for monitoring
diaphragm function and inspiratory effort will be compared to the more invasive
gold standard.

To validate two less complex techniques, electrical activity of the diaphragm
and ultrasound of the diaphragm, compared to the gold standard
(transdiaphragmatic pressures) for monitoring diaphragm function and
inspiratory effort during assisted MV in children.

This study is a single centre non-therapeutic observational pilot study
performed in mechanical ventilated children admitted to a pediatric intensive
care unit (PICU) at a tertiary university hospital.
Two less complex techniques will be used to measure respiratory effort on the
ventilator which will be compared to the gold standard. Measurements will take
about 15 minutes each day as long as the patient is on the ventilator.

Participation in this study is associated with minimal burden and negligible
risks. All mechanical ventilated infants are sedated. Ultrasound for evaluating
the respiratory muscles is a non-invasive technique not interfering with the
normal clinical care of these infants and is nowadays standard daily care on
PICU. No change in sedation level is necessary for study puroses.
In addition no unexpected clinically relevant findings are expected to be found
during diagostic techniques performed for the study.
Currently selected ventilated patients are instrumented with an EAdi-catheter
(Maquet Critical Care, Solna, Sweden) for monitoring the patient*s inspiratory
activity and to detect patient-ventilator dyssynchrony. At our PICU this is
commonly used and is part of daily care. For this study, to measure esophageal
and gastric pressure, 2 additional balloons are integrated in the EAdi catheter
(Neurovent® catheter), so no additional catheter has to be inserted. This
Neurovent® catheter is already standard of care at our adult ICU at the NExCOB
(Nijmegen expertisecentrum voor Ontwenning van de beademing) and has been used
for diagnostic purposes in children at our PICU as well. Furthermore it is
routinely used in several studies carried out by our research team without
additional risks.
With this study more insight in the respiratory physiology of mechanical
ventilated children on PICU is generated and less invasive ways to guide
ventilation will be studied. Information about the respiratory (dys)function
acquired during MV is an important clinical priority both for diagnostic
purposes and to follow patients status over time. Titrating ventilator support
to maintain normal levels of inspiratory effort may prevent changes in
diaphragm configuration associated with MV.