Surgery – Diagnostic testing – Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
2002-11-27
2003-12-30
Shaver, Kevin (Department: 3732)
Surgery
Diagnostic testing
Measuring or detecting nonradioactive constituent of body...
Reexamination Certificate
active
06671529
ABSTRACT:
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
(Not Applicable)
BACKGROUND OF THE INVENTION
The present invention relates generally to oxygen delivery systems and more particularly to a closed loop system and method for automatically delivering fractionally inspired oxygen (FiO
2
).
Very low birth weight infants often present with episodes of hypoxemia. These episodes are detected by arterial oxygen saturation monitoring by pulse oximetry (SpO
2
) and are usually assisted with a transient increase in the fraction of inspired oxygen (FiO
2
).
Given the rapid onset and frequency at which most of these episodes of hypoxemia occur, maintaining SpO
2
within a normal range by manual FiO
2
adjustment during each episode is a difficult and time-consuming task. Nurses and respiratory therapists respond to high/low SpO
2
alarms. Under routine clinical conditions, the response time is variable and the FiO
2
adjustment is not well defined. This exposes the infants to periods of hypoxemia and hyperoxemia which may increase the risk of neonatal chronic lung disease and retinopathy of prematurity.
Thus, a need exists for a system that can automatically adjust FiO
2
. Prior art systems exist which automatically adjusts FiO
2
. Such systems have had positive results. However, existing systems fail to respond to rapid SpO
2
changes and require manual intervention. Thus, a need exists for an automated system for adjusting FiO
2
which will respond to rapid SpO
2
changes. The system should not require manual intervention, but should allow for manual intervention, if desired. The system should also allow for gradually weaning the FiO
2
as soon as an episode begins to resolve.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, a system is provided for delivering fractionally inspired oxygen (FiO
2
) to a patient. The system includes a device, such as a pulse oximeter, for obtaining an arterial hemoglobin oxygen saturation signal (SpO
2
). An algorithm uses the SpO
3
to determine the appropriate FiO
2
to deliver to the patient. The algorithm adjusts the FiO
2
level of an air-oxygen mixer of an oxygen delivery device, such as a mechanical ventilator.
In accordance with other aspects of the invention, SpO
2
levels, including a target (normoxemia) range, are defined. SpO
2
values above the normoxemia range are considered to be hyperoxemic and values below the normoxemia range are considered to be hypoxemic.
In accordance with further aspects of the invention, a determination is made as to whether the SpO
2
signal is a valid signal. If the SpO
2
signal is not a valid signal, the FiO
2
to be delivered to the patient is determined based on a backup value. If the SpO
2
signal is a valid signal and closed loop mode is not enabled, the FiO
2
to be delivered to the patient is determined based on a backup value. If the signal is valid and closed loop mode is enabled, the FiO
2
to be delivered to the patient is determined based on the current SpO
2
and the trend. The trend is determined by calculating a slope using previous SpO
2
values. The determined FiO
2
is then delivered to the patient, for example, using a ventilator or an air-oxygen gas mixer.
In accordance with still further aspects of the invention, a user interface is provided. The user interface displays status information. The user interface also displays alerts. The user interface can also be used to view and modify user settings/parameters.
REFERENCES:
patent: 2414747 (1947-01-01), Kirschbaum
patent: 3734091 (1973-05-01), Taplin
patent: 4121578 (1978-10-01), Torzala
patent: 4326513 (1982-04-01), Schulz et al.
patent: 4612928 (1986-09-01), Tiep et al.
patent: 4665911 (1987-05-01), Williams et al.
patent: 4671297 (1987-06-01), Schulze, Jr.
patent: 4869253 (1989-09-01), Craig et al.
patent: 4889116 (1989-12-01), Taube
patent: 4932402 (1990-06-01), Snook et al.
patent: 4972842 (1990-11-01), Korten et al.
patent: 4986268 (1991-01-01), Tehrani
patent: 5103814 (1992-04-01), Maher
patent: 5119815 (1992-06-01), Chance
patent: 5251632 (1993-10-01), Delpy
patent: 5315990 (1994-05-01), Mondry
patent: 5365922 (1994-11-01), Raemer
patent: 5388575 (1995-02-01), Taube
patent: 5560352 (1996-10-01), Heim et al.
patent: 5682877 (1997-11-01), Mondry
patent: 5752509 (1998-05-01), Lachmann et al.
patent: 6035223 (2000-03-01), Baker, Jr.
patent: 6148814 (2000-11-01), Clemmer et al.
patent: 6186142 (2001-02-01), Schmidt et al.
patent: 6192260 (2001-02-01), Chance
patent: 6272363 (2001-08-01), Casciani et al.
patent: 6371114 (2002-04-01), Schmidt et al.
patent: 6387324 (2002-05-01), Patterson et al.
patent: 0658331 (1995-06-01), None
P.E. Morozoff & R.W. Evans. “Closed-Loop Control of Sao2 in the Neonate”. (Biomedical Instrumentation & Technology 1992; 26:117-123).
Thomas East et al. “Can Pulse Oximetry be Used to Reliably Predict Arterial Oxygenation”. (Society of Critical Care Medicine Jan.-Feb. 1995; poster presentation).
Vinod K. Bhutani et al. “Adpative Control of Inspired Oxygen Divery to the Neonate” (Pediatric Pulmondogy 1992; 14:110-117).
Fleur T. Tehrani. “A Mircocomputer Oxygen Control System for Ventilatory Therapy”. (Annals of Biomedical Engineering 1992;vol. 20:547-558).
Thomas P. Laubscher et al. “Automatic Selection of Tidal Volume, . . . for Close-Loo Controlled Ventilation”. (International Journal of Clinical Monitoring and Computing 1994; 11:10-30).
Michael Jastremski et al. “A Model for Technology Assessment as Applied to Closed Loop Infusion Systems”. (Critical Care Medicine Oct. 1995; vol. 23:1-18).
F. Lemaire & Alain Hart. “A Knowledge-Based System for Assisted Ventilation of Patients in ICU”. (International Journal of Clinical Monitoring and Computing 1992; 9:239-250).
Dwayne R. Westenskow. “Automating Patient Care with Closed-Loop Control”. (Images, Signals and Devices 1986; vol. 3, No. 2, pp. 14-20).
M. Blasovszky et al. “Improving Instrumentation for Hospital Care of Neonates in Hungary”. (IEEE Engineering In Medicine and Biology Mar.-Apr. 1998; pp. 59-65).
Norbert Weiler et al. “Adaptive Lung Ventilation . . . Automatic Response to Transitions to and from One-Lung Ventilation”. (Journal of Clinical Monitoring and Computing 1998; 14:245-252).
1999 Abstract Form from 1999 ALA/ATS International Conference (2 pages) with hard copy of Power Point presentation (22 pages) presented at American Thoracic Society-American Lung Association meeting in Apr. of 1999 in San Diego California and at the Society of Pediatric Research—American Academy of Pediatric meeting in May of 1999 in San Francisco, California. Abstract and documents apply to both meetings.
James H. Strickland et al. “A Computer-Controlled Ventilator Weaning System”. (Chest 1991; vol. 100:pp. 1096-1099).
Suzanne M. Burns. “Weaning from Mechanical Ventilation: A Method for Assessment and Planning”. (Clinical Issues Aug. 1991; vol. 2, No. 3, pp. 372-387).
Hillary Don. “Hypoxemia”. pp. 62-63.
Bancalari Eduardo H.
Claure Nelson R.
Ramana Anuradha
Shaver Kevin
Stetina Brunda Garred & Brucker
University of Miami
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