1. Field
The present disclosure generally relates to systems and methods providing mechanical ventilation to assist a patient, and, in particular, relates to control of the ventilator settings by the patient.
2. Description of the Related Art
People who have been seriously injured or undergone major surgery may have difficulty in breathing on their own. In order to ensure that sufficient oxygen is available in the lungs for absorption, a ventilator may be used to mechanically assist or replace spontaneous breathing. Positive-pressure ventilators work by increasing the patient's airway pressure through a patient device such as a mask or an endotracheal or tracheostomy tube. The positive pressure forces air to flow into the lungs. When the ventilator reduces the pressure, the elastic contraction of the chest wall collapses the lungs and pushes a volume of air out. The volume of air that is introduced into the lungs on each cycle is the “tidal volume.”
Patients suffering from a severe lung injury or an illness such as chronic obstructive pulmonary disease may require long-term use of a ventilator. Some patients find that certain modes of operation or settings within the mode are more comfortable than others. It is frequently possible for the caregiver to adjust the ventilator to make the patient more comfortable while maintaining the prescribed treatment protocol, although this may be a lengthy process and the settings that are most comfortable may change repeatedly during the treatment. Typically, the patient must request the caregiver to adjust the settings of the ventilator, yet the patient is not likely to know what to ask the caregiver to adjust nor how much to change the setting.
It is normally desirable to end the use of a mechanical ventilator as early as possible. Many of the current protocols for transitioning a patient off of a mechanical ventilator, or “weaning” the patient, include one or more “spontaneous breathing trials” or “weaning trials” where the ventilator support is reduced or stopped for a period of time and the patient is monitored during the trial to identify signs of distress or difficulty. If the patient is able to complete the prescribed weaning trials, the ventilator is typically removed. The response of every patient is different, however, and one patient may be ready to discontinue use of the ventilator very quickly while another patient may require multiple repetitions of the weaning trials before they are strong enough to discontinue use of the ventilator. There is no current way for a patient to influence the course of the weaning trial to complete the trial faster or slower.
The disclosed system and method describe a ventilator system that is configured to allow the patient to control at least one of the control parameters of the ventilator. In certain embodiments, the physician may prescribe a weaning protocol that comprises a series of stages leading from an initial stage associated with greater support of the patient (such as full support) by the ventilator to a final stage that is associated with readiness of the patient to discontinue use of the ventilator. Each stage comprises a set of specified values of one or more control parameters. The patient can change the ventilator from one stage to an adjacent stage in the series. Each stage may include a lock-out time period where the patient cannot change the stage in the direction towards the final stage until the lock-out time period has elapsed while operating at the current stage. The ventilator may display one or more health parameters to assure the patient that they are safe, indicators of which stage is currently in use, or progress parameters indicating the progress of the patient towards readiness to discontinue use of the ventilator to encourage the patient in moving toward the final stage. In other embodiments, the physician may specify an operating range for one or more control parameters and the patient may vary these control parameters within the operating range to maximize their comfort.
In certain embodiments, a method of controlling a ventilator is disclosed. The method comprises the steps of providing a patient with a ventilator patient control interface through which a patient controls at least one control parameter of a ventilator and configuring a processor to control the ventilator in response to the ventilator patient control interface such that the patient controls the at least one control parameter of the ventilator in accordance with pre-set limits on changes to the at least one control parameter.
In certain embodiments, a ventilation system for use by a patient is disclosed. The ventilator system comprises a patient device attached to the patient, the patient device configured to introduce gas into the lungs of the patient; a gas control module fluidically coupled to the patient device, the gas control module configured to controllably provide a gas to the patient device according to at least one operating parameter; a memory configured to store one or more executable instructions and data; a patient control interface configured to control the at least one operating parameter of the gas control module and to be accessible by the patient; and a processor coupled to the gas control module, the patient control interface, and the memory, the processor configured to retrieve the instructions and data from the memory and operate the gas control module in accordance with the retrieved instructions and data and in response to the patient control interface.
The accompanying drawings, which are included to provide further understanding and are incorporated in and constitute a part of this specification, illustrate disclosed embodiments and together with the description serve to explain the principles of the disclosed embodiments. In the drawings:
While positive-pressure ventilators are generally acknowledged to be uncomfortable for a patient, current ventilators do not allow the patient to control any aspect of the operation of the ventilator to improve their comfort. Similarly, while it is generally agreed that it is desirable to get a patient off of the use of a ventilator as soon as possible, current ventilators do not allow the patient to control any aspect of the weaning process such that they might complete the weaning faster. The disclosed system and methods provides patients with the ability to control certain parameters of a ventilator to maximize their comfort or participate in the weaning process as well as provide feedback to the patient to encourage and assist them in the weaning process.
Ventilators 15 may be operated in a variety of modes, including control mode ventilation, intermittent mandatory ventilation, and pressure control ventilation. Some modes, such as control mode ventilation, generate an inspiratory tidal volume while others, such as pressure control ventilation, provide a specified pressure for a specified inspiratory time. Other modes, such as pressure support ventilation or continuous positive airway pressure (CPAP), provide a constant pre-set pressure during a breath or continuously and may be used as part of the weaning process.
Ventilators have a large number of operating parameters that are used in a variety of combinations in the various modes. The settings of each parameter used in a prescribed mode may also be specified by a doctor within a wide range. Table 1 lists some example operating parameters and operational ranges.
where PEEP is an acronym for “positive end-expiratory pressure” and is the pressure that is maintained by the ventilator at the end of expiration to keep the airway pressure above the atmospheric pressure.
As a patient 10 recovers from the injury or surgery that led to their being placed on a ventilator 15, caregivers will often change the mode of operation of the ventilator 15 or reduce the settings to reduce the level of support provided to the patient 10 by the ventilator 15. The objective is to discontinue the use of the ventilator 15 completely as soon as possible with as little risk to the patient 10 as possible. Trials of spontaneous breathing are usually conducted and have been shown to accurately predict the success of spontaneous breathing if the patient 10 were to be removed from the ventilator 15. While the mode of ventilator operation and the settings of the operating parameters are selected by the physician depending upon the individual case, an example of a spontaneous breathing trial is to change the mode of operation to CPAP with a pressure setting of 5 cm H2O. Such a trial, however, may be too large a change from current mode and settings of the ventilator 15. In such cases, a series of stages may be specified, wherein the nurse changes the settings to those specified in the first stage and observes the patient 10 for a specified amount of time. If the patient 10 does not exhibit signs of distress or difficulty in breathing, the nurse will change the settings to those of the next stage. If the patient 10 is able to reach the final stage without observed difficulty, the doctor may order that that patient device 16 be removed, referred to as “extubation.” This series of trial stages may take several days, especially if the patient 10 experiences difficulty or anxiety at any stage.
Ventilators 15 often also monitor patient parameters and may have alarms that can be set to trigger at certain levels. Table 2 lists examples of monitored parameters.
In
In the stages (n−1) and n that are depicted in
In certain embodiments, the patient 10 is able to control the ventilator 15 to transition between the stages defined in the protocol of
As using a ventilator 15 may be inherently uncomfortable and it may increase the discomfort to move upward in the weaning protocol even when the patient 10 is not at an increased risk, it may be desirable to provide assurance to the patient 10 that they are not at risk of injury. To this end, feedback is provided displaying health parameters of the patient 10 that are, in this example, the measured value of the patient's blood oxygen level 40 and the measured value of the patient's breathing rate 42. To provide an intuitive guide to the desired ranges of these health parameters, the displays 40 and 42 may have adjacent colored bars that may be red to indicate undesirable ranges and green to indicate desirable ranges of each parameter. In this example, blood oxygen 40 has a red bar 44 and a green bar 46 while breathing rate has red bars 50 and 52, as the patient's breathing rate could be undesirably high or low, as well as a green target bar 54. By examining the displays 40 and 42, the patient 10 and their family can verify that the patient is not in physical danger although they may be in discomfort.
To further encourage a patient 10 to progress through the stages of the weaning process, it may be desirable to provide feedback to the patient 10 showing how much progress that they have made toward the final stage of the weaning process. In this example, the feedback includes a display of the stage number 56 and a percentage of the progress 58 towards the final stage that is associated with the current stage. In other embodiments, display 56 may include a “X of Y” format to include the total number of stages and to show the progress. For example, the display 56 could show “5 of 7” to indicate that stage 7 is the final stage and that the patient is currently in stage 5.
In embodiments wherein one or more stages include a lock-out time during which the ventilator 15 will not change to a higher stage even if the patient 10 presses the up button 32, it may be desirable to provide feedback to the patient 10 regarding the amount of time remaining in the current lock-out period. To this end, display 60 is provided in this example to display the minutes remaining in the current lockout period. In certain embodiments, if a stage does not have a lock-out period specified, display 60 may be zero. In certain embodiments, the display 60 may change to a text term such as “READY” instead of a zero.
The patient control interface may be configured in a variety of alternate configurations without departing from the scope of this disclosure and the related claims. Alternate display devices, such as liquid crystal displays (LCDs) or color display screens, may combine multiple displays. Alternate input devices, such as a touch-screen, mouse, joystick, etc. may be used instead of the button described above. The patient control interface 17 may be provided by a device separate from the ventilator 15, such as an application running on a desktop computer or a cell phone.
In the example of
The nurse may initiate a termination of the patient-controlled operation of the ventilator 15 in step 130, whereupon the process branches along the “YES” path to “END” the patient-controlled operation of the ventilator 15. An alternate action by the nurse would be to turn off the ventilator 15, such as when the patient 10 successfully completes the weaning process and the patient device 16 is removed, which follows the same process path to “END”. If the nurse does not initiate an action, the process may then proceed to step 135 wherein the patient 10 adjusts the patient control interface 17. The process then moves to decision block 140 where, if a lock-out time has been specified and the lock-out time has not yet been completed for the current stage, the process will branch along the “NO” path back to step 125. If the lock-out time has been completed, or there is no lock-out time specified for the current mode of operation, the process moves to step 145 where the settings of the operating parameters that were specified in 110 and 115 are changed according to the patient's adjustment of the patient control interface 17 and the process then branches back to step 125 to operate at the new settings, which have become the current settings. The ventilator 15 continues to loop through the steps 125-135-140-145 until a nurse takes an action in step 130.
Ventilator assembly 200 is connected to a patient device 16 that may be any of the masks or intubation devices known to those of ordinary skill in the art for introducing gas into the lungs of a patient, including full-face or partial-face masks, an endotracheal tube, or a tracheotomy tube. The connection between ventilator assembly 200 and patient device 16 is, in this example, accomplished by an air hose 230 from the gas control module 215 to the patient device 16. In certain embodiments, air hose 230 includes a supply hose and a return hose (not shown separately) such that the patient's exhaled gas is returned to the ventilator assembly 200.
Ventilator assembly 200 is also coupled, in this example, from communication module 235 to a patient control interface 17 through a communication link 245. In certain embodiments, such as the wireless handheld 17 of
In certain embodiments, the communication module 235 of ventilator 200 may be linked to an external server or database 250 through a network 250 such as an Ethernet wired or wireless network. The processor 205 may retrieve executable instructions, information on prescribed operating parameters for a specific patient 10, or other data or information related to the operation of ventilator 200 or to the patient 10. Similarly, processor 205 may transmit information to the database 250, such as a history of operation, a log of patient actions, or a record of actuations of the patient control interface 17 regardless of whether the ventilator 200 implemented the associated change.
In this example, a ventilator controller 300 is coupled to the conventional ventilator 290. More precisely, the processor 305 of the ventilator controller 300 is coupled through a wired or wireless communication link 315 to communication module 235 and then to the processor 205 of the conventional ventilator 290. The processor 205 of ventilator 290 is configured to allow the operating parameters of the ventilator 290 to be changed remotely by signals received by the processor 201 through communication module 235. Processor 305 is coupled to memory 310 that comprises instructions on how to adjust the operating parameters of the ventilator 290. Processor 305 is also coupled to the patient control interface 17 through a wired or wireless linkage 320, wherein the processor 305 is configured to transmit signals to the processor 205 to change the operating parameters of the conventional ventilator 290 according to the input from patient control interface 17 and the instructions stored in memory 310. In this example, controller 300 is directly attached to the conventional ventilator 290. In certain embodiments, controller 300 is remote from the conventional ventilator 290. In certain other embodiments, the communication link 315 comprises the network 260, wherein controller 300 is connected to the same network 260.
In the previous detailed description, numerous specific details have been set forth to provide a full understanding of the present disclosure. It will be apparent, however, to one ordinarily skilled in the art that embodiments of the present disclosure may be practiced without some of the specific details. In other instances, well-known structures and techniques have not been shown in detail so as not to obscure the disclosure.
It can be seen that the disclosed embodiments of a patient-controlled ventilator provide a patient with the ability to adjust the operation of the ventilator within limits set by the doctor and other caregivers. In certain embodiments, the patient can progress at their own rate through a weaning process that includes a series of stages from full support to readiness to discontinue use of the ventilator. In certain embodiments, the patient receives feedback on their health to assure them that they are not at risk as they move through the stages of the weaning process. In certain embodiments, the patient receives positive feedback as they progress through the stages of the weaning process to encourage them to move forward as quickly as possible. In certain embodiments, there may be time lock-out periods or health parameters limits that prevent the patient from changing the ventilator to the next stage until the lock-out period has elapsed or while the health parameter is outside a limit. In certain embodiments, the patient can adjust one or more operating settings of the ventilator to improve their personal comfort.
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the terms “a set” and “some” refer to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the invention.
It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes may be rearranged. Some of the steps may be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
Terms such as “top,” “bottom,” “front,” “rear” and the like as used in this disclosure should be understood as referring to an arbitrary frame of reference, rather than to the ordinary gravitational frame of reference. Thus, a top surface, a bottom surface, a front surface, and a rear surface may extend upwardly, downwardly, diagonally, or horizontally in a gravitational frame of reference.
A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. A phrase such an embodiment may refer to one or more embodiments and vice versa.
The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs.
All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. §112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim.