Use of a Non-invasive Bio-impedance Cardiac Monitor, ICON™, to Detect and Trend Hemodynamic Variables During Dexmedetomidine Sedation in Children Undergoing Pulmonary Function Testing

Traditionally the measurements of cardiac indices and hemodynamic variables require invasive monitors such as pulmonary thermodilution catheters and transesophageal Doppler echocardiography. In recent years, electrical cardiometry has been used for the non-invasive determination of stroke volume, cardiac output, and other hemodynamic parameters in adults, children, and neonates. Electrical cardiometry has been validated against "gold standard" methods such as thermodilution and is a proprietary method trademarked by Cardiotronic, Inc. (La Jolla, CA). Cardiotronic markets the ICON™. It is FDA-approved for use in pediatric and adult patients, is currently used for clinical purposes in the BCH MSICU at 11 South.

The ICON™ is a comprehensive, standalone hemodynamic monitor, which provides a complete hemodynamic monitoring system that provides user-defined hemodynamic parameters. It provides a continuous trend of cardiac output and stroke volume associated with rapid changes in vital signs with minimal risk to the patient.

The ICON™ monitor has been used in Boston Children's Hospital to determine the hemodynamic changes in children aged 1 month to 18 years of age who received dexmedetomidine sedation for CT and Nuclear Medicine.

Dexmedetomidine (DEX) has been found to be an effective drug in the pediatric population in both the intensive care unit and for procedures in Radiology. In a recent study, DEX caused bradycardia (3%), hypotension (9%) and hypertension (8%) in pediatric critical care patients. Intravenously administrated sedation. DEX will be delivered as per the DEX order set used for non-painful procedures in the radiology department. As an alpha 2 adrenergic agonist, DEX produces hemodynamic changes to blood pressure and heart rate. To precisely follow the trend of complex changes in systemic vascular resistance, cardiac output and stroke volume during DEX administration, would ideally be with invasive intravascular monitors which would not be warranted in pediatric sedation procedures. However, a minimal risk non-invasive cardiac output monitor such as the ICON can measure, detect, and trend these physiological changes in the neonates and infants who are receiving DEX for pulmonary function tests.

Children with certain lung conditions undergo pulmonary function tests (PFT) which are currently being performed using chloral hydrate administered by the responsible and sedation credentialed pulmonologist (Dr. Lawrence Rhein). Chloral hydrate is inconsistent and unreliable in producing adequate sedation for a successful PFT study. Sedation physicians from the BCH Department of Anesthesia have agreed to provide sedation for these patients with dexmedetomidine (DEX), using the same approved protocols that are being used in the BCH Department of Radiology for non-painful imaging studies.