Automated Closed Loop Control of Inspired Oxygen Concentration

Division of Neonatology, Department of Pediatrics, University of Miami Miller School of Medicine, Miami, Florida.
Respiratory care (Impact Factor: 1.84). 01/2013; 58(1):151-61. DOI: 10.4187/respcare.01955
Source: PubMed

ABSTRACT Oxygen therapy is extensively used in premature infants and adults with respiratory insufficiency. In the premature infant the goal during manual control of the F(IO(2)) is to maintain adequate oxygenation and to minimize the exposure to hypoxemia, hyperoxemia, and oxygen. However, this is frequently not achieved during routine care, which increases the risks of associated side effects affecting the eye, lungs, and central nervous system. In the adult the primary goal is to avoid hypoxemia, but conventional methods of oxygen supplementation may fall short during periods of increased demand. On the other hand, there are growing concerns related to unnecessarily high F(IO(2)) levels that increase the exposure to hyperoxemia and excessive oxygen use in settings where resources are limited. Systems for automated closed loop control of F(IO(2)) have been developed for use in neonates and adults. This paper will give an overview of the rationale for the development of these systems, present the evidence, and discuss important advantages and limitations.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Architectures capable of using an algorithm to modify actuation based on measured signals are often called "closed-loop" systems. While such systems are traditionally thought to rely on algorithms residing in device firmware, these may also reside outside the device in a host processor located physically nearby, or on a cloud-based architecture. In order to serve the potentially broad array of data processing modalities, we have developed an application programming interface (API). The API enables access to the sensing and stimulation capabilities of an implantable bi-directional neural interface. Systems using the API on different hardware/software platforms could measure neural signals, process signals in real-time, and modulate stimulation parameters using a variety of algorithms. This flexibility allows increased algorithm access and enables rapid prototyping for potentially improved technology solutions. The system performance was characterized using a signal generator to input square wave pulses to a Simulink model via the API. Closed-loop stimulation latencies of around 600ms were achieved. I. NEED FOR PROTOTYPING SYSTEMS FOR CLOSED-LOOP NEUROMODULATION Neurostimulation is used to treat a variety of neurological diseases such as Parkinson's disease, essential tremor, urinary incontinence, and chronic pain. To function properly, these technologies require both accurate hardware placement (e.g., placing leads in the correct nervous system location) as well as therapy parameter setting optimization (e.g. electrode selection, stimulation amplitude, pulse width, and frequency). Selection of optimal parameters is largely an empirical process that may involve multiple, time-consuming device programming sessions spread apart by weeks or months. Outside of these sessions, the ability to make stimulation parameter adjustments is generally limited.
    IEEE EMBS Neural Engineering, San Diego, CA, USA; 11/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: Supplemental oxygen is commonly provided during transition of neonates immediately after birth. Whereas an initial FiO2 of 0.21 is now recommended to stabilize full-term infants in the delivery room, the best FiO2 to start resuscitation of the very low birth weight infant (VLBWI) immediately after delivery is currently not known. Recent recommendations include the use of pulse oximetry to titrate the use of supplemental oxygen. As reference values for pulse oximetry during the first minutes of life have become available, automated FiO2-adjustments are feasible and may be very useful for delivery room care to limit oxygen exposure. Beyond neonatal transition, preterm infants in the neonatal intensive care unit (NICU) commonly require supplemental oxygen to avoid hypoxemia, especially VLBWI receiving respiratory support because of poor respiratory drive and/or lung disease. For respiratory care of newborn infants in the NICU automated FiO2-adjustment systems have been developed and have been studied in preterm infants for limited time frames using short-term physiological outcomes. These studies could demonstrate short-term benefits such as more stable arterial oxygen saturation. Recent clinical trials have shown that oxygen targeting may significantly affect mortality and morbidity. Therefore, randomized controlled trials are needed to study the effects of automated FiO2-adjustment on long-term outcomes to prove possible benefits on survival, the rate of retino-pathy of prematurity and on neuro-development-al outcome.
    Klinische Pädiatrie 07/2014; 226(4):204-210. DOI:10.1055/s-0034-1375617 · 1.90 Impact Factor
  • Journal of Pediatrics 07/2014; 165(4). DOI:10.1016/j.jpeds.2014.06.049 · 3.74 Impact Factor