Autonomous drug delivery system

Description

PRIORITY CLAIM TO RELATED PROVISIONAL APPLICATION

The present application claims priority benefit under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 61/932,437 filed Jan. 28, 2014, titled Opioid Agonist Rescue. The above-cited provisional patent application is hereby incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

Pulse oximetry is a widely accepted noninvasive procedure for measuring the oxygen saturation level of arterial blood, an indicator of a person's oxygen supply. A typical pulse oximetry system utilizes an optical sensor attached to a fingertip to measure the relative volume of oxygenated hemoglobin in pulsatile arterial blood flowing within the fingertip. Oxygen saturation (SpO₂), pulse rate and a plethysmograph waveform, which is a visualization of pulsatile blood flow over time, are displayed on a monitor accordingly.

Conventional pulse oximetry assumes that arterial blood is the only pulsatile blood flow in the measurement site. During patient motion, venous blood also moves, which causes errors in conventional pulse oximetry. Advanced pulse oximetry processes the venous blood signal so as to report true arterial oxygen saturation and pulse rate under conditions of patient movement. Advanced pulse oximetry also functions under conditions of low perfusion (small signal amplitude), intense ambient light (artificial or sunlight) and electrosurgical instrument interference, which are scenarios where conventional pulse oximetry tends to fail.

Advanced pulse oximetry is described in at least U.S. Pat. Nos. 6,770,028; 6,658,276; 6,157,850; 6,002,952; 5,769,785 and 5,758,644, which are assigned to Masimo Corporation (“Masimo”) of Irvine, Calif. and are incorporated in their entirety by reference herein. Corresponding low noise optical sensors are disclosed in at least U.S. Pat. Nos. 6,985,764; 6,813,511; 6,792,300; 6,256,523; 6,088,607; 5,782,757 and 5,638,818, which are also assigned to Masimo and are also incorporated in their entirety by reference herein. Advanced pulse oximetry systems including Masimo SET® low noise optical sensors and read through motion pulse oximetry monitors for measuring SpO₂, pulse rate (PR) and perfusion index (PI) are available from Masimo. Optical sensors include any of Masimo LNOP®, LNCS®, SofTouch™ and BIue™ adhesive or reusable sensors. Pulse oximetry monitors include any of Masimo Rad8®, Rad5®, Rad®-5v or SatShare® monitors.

Advanced blood parameter measurement systems are described in at least U.S. Pat. No. 7,647,083, filed Mar. 1, 2006, titled Multiple Wavelength Sensor Equalization; U.S. Pat. No. 7,729,733, filed Mar. 1, 2006, titled Configurable Physiological Measurement System; U.S. Pat. Pub. No. 2006/0211925, filed Mar. 1, 2006, titled Physiological Parameter Confidence Measure and U.S. Pat. Pub. No. 2006/0238358, filed Mar. 1, 2006, titled Noninvasive Multi-Parameter Patient Monitor, all assigned to Cercacor Laboratories, Inc., Irvine, Calif. (Cercacor) and all incorporated in their entirety by reference herein. Advanced blood parameter measurement systems include Masimo Rainbow® SET, which provides measurements in addition to SpO₂, such as total hemoglobin (SpHb™), oxygen content (SpOC™), methemoglobin (SpMet®), carboxyhemoglobin (SpCO®) and PVI®. Advanced blood parameter sensors include Masimo Rainbow® adhesive, ReSposable™ and reusable sensors. Advanced blood parameter monitors include Masimo Radical-7™, Rad87™ and Rad57™ monitors, all available from Masimo. Such advanced pulse oximeters, low noise sensors and advanced blood parameter systems have gained rapid acceptance in a wide variety of medical applications, including surgical wards, intensive care and neonatal units, general wards, home care, physical training, and virtually all types of monitoring scenarios.

SUMMARY OF THE INVENTION

Hospital patients and out-patients may experience negative effects from various pharmaceutical drugs prescribed for treatment. These negative effects may be due to overdose, underdose or adverse reactions to these drugs. As one example, opioids are often given to post-surgical patients for pain management, and while opioid use is safe for most patients, opioid analgesics are often associated with adverse reactions, such as respiratory depression as a result of excessive dosing, improper monitoring, medication interactions and adverse reactions with other drugs. Complications from opioid use are inevitable and not always avoidable. However, when a patient dies because such complications were not timely recognized or treated appropriately, it is termed a “failure to rescue.”

Failure to rescue in the case of opioid overdose can be largely prevented by an advantageous autonomous administration of an opioid antagonist. Similarly, other serious patient conditions such as heart arrhythmia, high or low heart rate, high or low blood pressure, hypoglycemia and anaphylactic shock, to name a few, may be moderated by the autonomous administration of an appropriate rescue drug. An autonomous drug delivery system (ADDS) advantageously utilizes physiological monitor outputs so as to automatically give at least one bolus of at least one drug or medicine when certain criteria and confidence levels are met. In addition, an emergency button is provided to manually trigger administration of such a rescue drug or medicine. In an embodiment, the emergency button may be triggered remotely. ADDS advantageously responds with a rescue drug when delay in clinician response would otherwise result in patient injury or death.

One aspect of an autonomous drug delivery system is a housing with a front panel and a drug compartment. A display and buttons are disposed on the front panel. An IV injector is disposed in the drug compartment, and a nozzle extending from the housing is in mechanical communications with the IV injector. In an embodiment, the IV injector has a drug reservoir, a piston partially disposed within and extending from the drug reservoir and a drive motor in mechanical communications with the piston. The drive motor actuates so as to drive the piston against a drug containing bolus disposed within the drug reservoir. The piston causes the drug to extrude from the nozzle.

Another aspect of an autonomous drug delivery system is receiving a physiological parameter indicative of a medical state of a person and calculating a trigger condition and a corresponding confidence indicator. An alarm occurs if the trigger condition exceeds a predetermined threshold. A drug is administered to the person if the alarm is not manually acknowledged within a predetermined time interval.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-C are front, front partial-cutaway, and cutaway drug reservoir views of an autonomous drug delivery system (ADDS) embodiment;

FIG. 2 is a front view of an autonomous drug delivery system configured with a conventional IV drip;

FIG. 3 is a front view of an autonomous drug delivery system configured with an IV drip and a patient controlled analgesia (PCA) pump;

FIG. 4 is a block diagram of an autonomous drug delivery system having fluid connectivity to a patient and electronic communications with sensor(s) and monitor(s);

FIG. 5 is a single-rail drug administration decision flow chart;

FIG. 6 is a cutaway dual drug reservoir view of an autonomous drug delivery system embodiment;

FIG. 7 is a dual-rail drug administration decision flow chart; and

FIG. 8 is a block diagram of an autonomous drug delivery system signal processing and instrument management.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1A-C illustrate an autonomous drug delivery system (ADDS) 100 that inputs physiological parameters generated by one or more patient monitors, such as SpO₂, PR, RR, EtCO₂ and BP, and evaluates certain criteria and confidence levels based upon those parameters, so as to automatically give a bolus of a rescue drug. As shown in FIG. 1A, the autonomous drug delivery system 100 has a control section 102 and a drug section 108. The control section 102 has a front panel 104 and an electrical interface (not visible). The front panel 104 provides a user interface including a user display 110, such as an LED or LCD readout of device and patient status, among other data; control buttons 120 such as power on/off, reset, mode among other functions, and an emergency button 130 to manually trigger administration of the rescue drug. The emergency button 130 may have a flip-up cover or other safety mechanism, such as a simultaneous press with another button, so as to prevent inadvertent drug administration. The electrical interface communicates with patient monitor(s), alarm(s) and the drug section 108. The drug section 108 has a cover 109 concealing a drug administration device installed within a recessed compartment, described below.

As shown in FIG. 1B, the cover 109, once flipped-up, slid-open, removed or otherwise opened, exposes an IV injector 150 having a drug reservoir 170, a piston 180 and a drive motor 190 disposed within a drug compartment 152. The drug reservoir 170 is configured to accept a disposable bolus of a rescue drug. When actuated, the motor 190 drives the piston 180 into the drug reservoir 170 so that the rescue drug contained in the drug reservoir 170 is expelled out of the nozzle 178 (FIG. 1C) and into an attached IV tube that carries the rescue drug to the patient, as described with respect to FIGS. 2-3, below. The bolus remains in the drug reservoir 170 until it is used or expires. In an embodiment, the expiration date is read from the bolus or otherwise entered into the ADDS memory (part of the DSP 810 FIG. 8).

As shown in FIG. 1C, in a ready position, the drug reservoir 170 has a generally-cylindrical enclosure 172 containing an unused rescue drug 174 and a piston 180. In particular, the piston 180 has a piston head 182 disposed within the enclosure 172 and a piston shaft 184 extending from the enclosure 172. The motor acts on the piston shaft 184 so as to move the piston head 182 from a first position (shown) distal the nozzle 178 to a second position proximate the nozzle, thus expelling the rescue drug from the reservoir 170 and into an IV tube (not shown) attached to the nozzle 178.

FIG. 2 illustrates a conventional IV drip configuration 200 incorporating an autonomous drug delivery system 100. In particular, an IV pole 10 mounts an IV bag 20 in fluid communications with a patient 1 via an IV line 30. Splicing the IV line is a one-way valve 50 in communications with the ADDS 100 via a line shunt 40. In the event the ADDS 100 is triggered, either manually via the emergency button 130 (FIG. 1A) or automatically via patient monitor inputs in communications with the control section 102 (FIG. 1A), the ADDS 100 injects its rescue drug 174 (FIG. 1C) into the shunt 40 via the one-way valve 50, which shuts off the IV line 30 blocking further IV bag 20 fluid.

FIG. 3 illustrates another conventional IV drip configuration 300 incorporating an autonomous drug delivery system (ADDS) 100 in addition to a patient controlled analgesia (PCA) pump 70. Similar to the FIG. 2 configuration described above, an IV pole 10 mounts an IV bag 20 in fluid communications with a patient 1 via an IV line 30. Splicing the IV line is a one-valve 50 in communications with the rescue device 100 via a line shunt 40. Also splicing the IV line is a one-valve 60 in communications with the PCA pump. As described above, in the event the ADDS 100 is triggered, either manually via the emergency button 130 (FIG. 1A) or automatically via patient monitor inputs in communications with the control section 102 (FIG. 1A), the ADDS 100 injects its rescue drug 174 (FIG. 1C) into the shunt 40 via the one-way valve 50, which shuts off the IV bag drip 20 and the PCA 70 analgesia.

The ADDS 100 may be used for a variety of medical emergencies and conditions in conjunction with a variety of rescue drugs. In one embodiment, the ADDS is advantageously used in conjunction with a patient controlled analgesia (PCA) device that delivers pain medication (e.g. morphine) upon patient demand (button push). Here, a patient is particularly vulnerable to inadvertently overdosing themselves to the point of respiratory failure. The ADDS inputs one or more parameters such as respiration rate, oxygen saturation, pulse rate, blood pressure and end-tidal CO₂ according to sensors attached to the patient and corresponding monitors and delivers an opiod antagonist such as Naloxone (Narcan), as described in further detail with respect to FIG. 4, below.

In other embodiments, the ADDS 100 is responsive to heart arrhythmias and delivers a rescue drug specific to the type of arrhythmia detected; is responsive to a high heart rate or low heart rate so as to deliver a heart rate regulating drug; is responsive to high or low blood pressure so as to deliver a blood pressure regulating drug; is responsive to hypoglycemia so as to deliver glucagon. In various embodiments, the ADDS 100 delivers compounded (mixed) formulas or more than one drug. This is accomplished through a mixture of drugs stored in a single reservoir or the use of multiple reservoirs. In all of these embodiments, the response is always a bolus (reservoir) administration. The drug is infused in a single administration step all at once (as opposed to over a prescribed amount of time as in a pump). The ADDS is capable of delivering multiple bolus doses, where subsequent bolus doses are ideally enabled after manual review of the initial, automatically delivered dose.

In an embodiment, the ADDS is configured to administer the bolus at a specific date and time, rather than in response to a monitored condition. In particular embodiments, bolus administration may be at multiple discrete times or over a specified time interval. When the ADDS is responsive to multiple physiological parameters received from one or more monitoring instruments, a prescribed minimum and or maximum interval from a previous dose or start time may be used.

In various situations, physiological “guard rails” must be maintained. (See, e.g. FIGS. 6-7). As an example, a hypotensive drug may be used to raise a patient's blood pressure during emergencies. As another example, a drug to regulate heart rhythm or suppress arrhythmias may be used. In an embodiment, the display 110 (FIG. 1A) indicates the device is working and receiving proper inputs. The ADDS 100 has a memory that records data that can be recalled to indicate a trigger cause for administering a rescue drug, such as the time and amount of drug administered and other logged conditions. In an embodiment, the rescue drug is administered in a progression rather than all-at-once. For example, a 10% dose may be given and the patient monitored for improvement, with additional doses spaced at intervals as needed. In an embodiment, a spring driven piston with a releasable catch is used to administer the rescue drug in lieu of a motor-driven piston. In an embodiment, an ADDS is advantageously integrated with a PCA device as a single instrument.

FIG. 4 illustrates an autonomous drug delivery system (ADDS) 410 having fluid connectivity to a patient 412 and electronic communications 424 with one or more monitors 420. One or more sensors 430 interface 432 with the patient 412, either by direct patient attachment or by remote sensing. For example, an optical sensor 430 may clip to a fingertip site 432 and provide pulsatile blood flow data via cable 422 to a pulse oximeter or blood parameter monitor 420. The pulse oximeter or blood parameter monitor 420 calculates physiological parameters 424, such as oxygen saturation and pulse rate, which are transmitted to the ADDS 410. The ADDS 410 responds to the parameters 424 by regulating (starting, increasing, decreasing or halting) the drug dosage 412 accordingly. The ADDS 410 may generate one or more alarms 414 to alert a caregiver. The caregiver may reset 416 an alarm upon responding to the alert. In an embodiment, communication between the ADDS 410 and a caregiver may be via a wired or wireless network and received at a nurses' station or equivalent.

FIG. 5 illustrates single-rail drug administration decisions 500. In this case, there is a single threshold (maximum or minimum) that if exceeded, triggers the ADDS device to administer a rescue drug to a patient. One or more parameters 501 are input to the ADDS device. An ADDS algorithm 510 calculates a trigger condition and an associated confidence indicator 512. If the ADDS trigger threshold is exceeded 520, an alarm 530 is triggered 522. Otherwise 524, ADDS does nothing. If the alarm 532 is timely acknowledged 540, such as a caregiver pressing an ADDS acknowledge button 544, then ADDS exits 560 and the alarm is silenced. If the alarm 532 is not acknowledged 542, then ADDS administers a rescue drug 550. Note that ADDS has a manual trigger 570 (button press), so as to manually trigger 572 drug administration 550 (see 130 FIG. 1A). In an embodiment, alarms 530 and corresponding acknowledgment times 540 may progress from a local alarm, a network alarm and finally a pager alarm before autonomous drug delivery 550 is triggered.

FIG. 6 illustrates a dual drug reservoir embodiment 600 of an autonomous drug delivery system. A first drug reservoir 670 and a second drug reservoir 680 may each contain the same drug for one or two separate doses or may contain different drugs for different single doses depending on the monitored condition. See, e.g. FIG. 7. The drug reservoirs 670, 680 share a common nozzle 662. The nozzle 662 has a junction 660 that connects fluid tubes 678, 688 to respective first 676 and second 686 reservoir nozzles. In an embodiment, a clinician has to re-enable the ADDS before a second dose is administered.

FIG. 7 illustrates dual-rail drug administration decisions 700. In this case, there are two thresholds: a maximum threshold (HI rail) and a minimum threshold (LO rail). If the maximum threshold is exceeded 720, i.e. one or more parameter values or combinations of parameter values goes over a predetermined limit, then the ADDS device is triggered to administer a rescue drug to a patient. Also, If the minimum threshold is exceeded 770, i.e. one or more parameter values or combinations of parameter values falls below a predetermined limit, then the ADDS device is triggered to administer a rescue drug to a patient. In an embodiment, one rescue drug may be administered upon exceeding the maximum threshold and a different rescue drug many be administered upon exceeding the minimum threshold. One or more parameters 701 are input to the ADDS device. ADDS algorithms 710 and 760 calculate maximum (HI) trigger conditions and minimum (LO) trigger conditions and associated confidence indicator. If either the HI or LO ADDS trigger thresholds are exceeded 720, 770 the corresponding alarm 730, 780 is triggered. Otherwise 724, 774 ADDS does nothing. If a HI or LO alarm 730, 780 is timely acknowledged, such as a caregiver pressing an ADDS acknowledge button 744, 794, then ADDS exits 741, 791 and the alarm is silenced. If the alarm 730, 780 is not acknowledged 742, 792 then ADDS administers the appropriate HI rail 745 or LO rail 795 rescue drug. Note that ADDS has manual triggers 799 (LO or HI button presses), so as to manually trigger either the LO rail drug 745 or the HI rail drug 795.

FIG. 8 illustrates an autonomous drug delivery system (ADDS) controller 800 having a digital signal processor (DSP) 810, an instrument manager 820 and interfaces 830. The DSP 810 has algorithms, such as described with respect to FIGS. 5-7, above, for calculating trigger conditions and confidences, alarm conditions and trigger timing 812. The instrument manager 820 interfaces with the DSP 810 so as to drive the ADDS displays 832 and alarms 834, to receive inputs from the buttons/keypad 835, to communicate with external monitors 837 that derive triggering parameters from patient sensors and to control the injector motor(s) and read injector status 839, such as bolus full/empty and injector active (delivering rescue drug). In an embodiment, DSP firmware records in memory the time and duration of events that triggered drug delivery, including a before and after history of monitor parameters that triggered drug administration.

An autonomous drug delivery system has been disclosed in detail in connection with various embodiments. These embodiments are disclosed by way of example only and are not to limit the scope of this disclosure or the claims that follow. One of ordinary skill in art will appreciate many variations and modifications.