Neonatal Intensive Care Units (NICUs) admit ~450,000 babies every year in the U.S. The monitoring of arterial blood gases is essential for managing any sick infant, but especially important in vulnerable, extremely premature infants, for whom even a minimal delay in appropriate interventions can be the difference between life and death. Intermittent monitoring of blood gases, as is traditional, provides only a spot check of physio-pathological status; the results are often delayed from the actual event triggering blood gas analysis, and the procedure, besides predisposing to iatrogenic infections, in itself is painful and over time can result in significant blood loss. Continuous non-invasive blood gas monitoring is preferable, but current non-invasive continuous modalities have significant limitations. An accurate, precise, and intrinsically safe system that exploits routinely performed intravascular catheterization (such as umbilical artery catheterization ? the standard of care for sick neonates) to obtain blood gas measurements continuously would be an important advance in monitoring critically ill neonates in NICUs. To address this need, we are developing an integrated fiber optic sensor umbilical (ISUM) catheter for blood gas monitoring in neonates. The ISUM catheter will fill the technological gap in continuous blood analysis by addressing the deficiencies shown in classical intravascular sensor probes, and will take advantage of the fact that most critically sick newborns in NICUs receive at least one intravascular catheter, often an umbilical arterial catheter. The sensor and the catheter are designed as an integrated unit for this specific application, and have the following advantages over previously described intravascular probes: (1) novel large area gas sensors, eliminating probe placement or movement artifacts; (2) dual O2 sensor and data fusion, eliminating wall effect, and improving reliability; and (3) ready-to-use sensors, with little or no delay in data acquisition; and (4) reduced cost, since highly repeatable sensor elements can be produced in batches of hundreds. In Phase I, the first ISUM catheters were designed, fabricated, and tested in animal models, incorporating sensors for both pO2 and pCO2. Excellent correlation between sensor readings and the gold standard technique for blood gas analysis was observed. None of the erroneous readings associated with prior intravascular devices were observed (which highlights the potential of the novel sensors for use in both infants and adults), and the safety of the new catheter was demonstrated. In the proposed Phase II work, additional sensors will be integrated, and advanced catheters will be designed and validated in the laboratory and in neonatal animal models closer to humans, which will lead to initial validation in human subjects. As soon as the proposed milestones are achieved, we will move to commercialize the ISUM catheter by starting the process for an FDA 510 (k) submission, and negotiating with investors for clinical trials and commercialization.
A vastly improved system for continuously monitoring blood gases of fragile premature infants and newborns fills an important gap in critical care. Our integrated fiber optic sensor umbilical catheter, which can measure blood oxygen, carbon dioxide, pH, and bicarbonate, could become a standard tool for critically sick neonates admitted to NICUs, reducing morbidity and mortality.
