Patent Application
20110178458
Laparoscopic surgery, also called minimally or less invasive surgery (MIS or LIS) or keyhole surgery is a modern surgical technique in which operations in the body are performed through small incisions as compared to the larger incisions needed in traditional surgical procedures. Gas such as carbon dioxide is delivered, via an insufflator, into a body cavity such as the abdomen leading to the formation of a pneumoperitoneum, thereby providing sufficient space for the surgeon to operate. The insufflator maintains the pneumoperitoneum and acts to renew the gas when leaks occur.
Gas such as carbon dioxide that is used for insufflation is both cold and dry and it is not surprising therefore those patients undergoing laparoscopic procedures often suffer a significant drop in core body temperature, which can result in considerable post-surgical pain and significant complications, such as cardiac stress, immunological and clotting problems, for the patient. By using standard thermo physical principles it has been shown that the major cause of patient heat loss is due to evaporation from the body acting to humidify the large volumes of dry insufflated gas at ATPD (Ambient Temperature Pressure Dry) passing into the body which is at BTPS (Body Temperature Pressure Saturated). If such heat loss could be minimised, post-operative pain and the significant side effects suffered by the patient could be considerably alleviated.
Various attempts have been made to condition insufflation gas by heating, humidifying and or filtering the gas. However in general, known insufflation gas conditioning systems suffer from one or more disadvantages including complexity of construction involving expensive monitoring devices, inaccurate control and/or difficulties in using them in a controlled working environment.
Some systems employ heat moisture exchangers (HME). These operate directly in the flow path of the insufflation gas and are therefore inherently susceptible to affecting pressure or flow, dependent upon their level of saturation and condition. Other systems require manual intervention to respond to patients needs by the adding of moisture. Other prior art devices require the cumbersome procedure of passing gas over and through non-heated or heated liquid containers. Such devices present the major drawback of impeding pressure measurement in the insufflation cavity.
Systems using conventional jet nebulisers or nebulisation catheters exhibit one or more of the following disadvantages: impaction of larger particles, fogging in the body cavity thus reducing the surgeon's visibility, interference with insufflator settings increasing flow/pressure in the system.
This invention is directed towards providing a method and an apparatus that will address at least some of these problems.
According to the invention there is provided an apparatus for use in laparoscopic surgery comprising:
In one embodiment the controller is configured to control operation of the aerosol generator responsive to the insufflation gas.
The controller may be configured to control operation of the aerosol generator responsive to the flow rate of the insufflation gas. The controller may be configured to control the flow rate of the fluid to be aerosolised.
In one case the apparatus comprises a device to determine the fluid flow rate of the insufflation gas. The determining device may comprise a flow sensor such as a flowmeter.
In one embodiment the first surface of the vibratable member is adapted to receive the fluid to be aerosolised.
The aerosol generator is configured to generate an aerosol at the second surface of the vibratable member.
In one embodiment the vibratable member is dome-shaped in geometry.
In one case the vibratable member comprises a piezoelectric element.
The apertures in the vibratable member are sized to aerosolise the first fluid by ejecting droplets of the first fluid such that the majority of the droplets by mass have a size of less than 5 micrometers. The apertures in the vibratable member may be sized to aerosolise the first fluid by ejecting droplets of the first fluid such that the majority of the droplets by mass have a size of less than 3 micrometers.
In one case the controller is configured to control the pulse rate at a set frequency of vibration of the vibratable member.
The controller may be impedance matched to the aerosol generator.
In one embodiment the apparatus comprises means to determine whether the fluid is in contact with the aerosol generator.
The determining means may be configured to determine at least one electrical characteristic of the aerosol generator. The determining means may be configured to determine at least one electrical characteristic of the aerosol generator over a range of vibration frequencies.
In one case the determining means is configured to compare the at least one electrical characteristic against a pre-defined set of data.
The invention also provides a method for carrying out a procedure involving insufflation comprising the steps of:—
The method may comprise the step of controlling the aerosolisation of the fluid.
In one case the method comprises controlling aerosolisation of the fluid responsive to the insufflation gas.
In one case the method comprises controlling aerosolisation of the fluid responsive to the flow rate of the insufflation gas.
The method may comprise controlling the flow rate of the fluid.
In one embodiment the method comprises the step of determining the flow rate of the insufflation gas.
In another embodiment the method comprises the step of determining if the fluid is in contact with an aerosol generator. This may involve determining at least one electrical characteristic of the aerosol generator. Electrical characteristics of the aerosol generator may be determined over a range of vibration frequencies.
In one case the method comprises the step of comparing the at least one electrical characteristic against a pre-defined set of data.
In one embodiment the method comprises the step of delivering the entrained fluid and insufflation gas into a body to insufflate at least part of the body.
In one case the fluid is an aqueous solution.
The aqueous solution may be saline having a salt concentration in the range of from 1 μM to 154 mM.
In one embodiment the fluid contains a therapeutic and/or prophylactic agent. The agent may be one or more selected from the group comprising an analgesic, and anti-inflammatory, an anti-infective, an anaesthetic, and an anti-cancer chemotherapy agent.
In one case the procedure is a laparoscopic procedure.
The invention will be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:—
a) and 7(b) are graphs of DC voltage versus time and AC voltage versus time respectively to achieve a 100% aerosol output;
a) and 8(b) are graphs of DC voltage versus time and AC voltage versus time respectively to achieve a 50% aerosol output—
a) and 9(b) are graphs of DC voltage versus time and AC voltage versus time respectively to achieve a 25% aerosol output—
Referring to
The apparatus comprises a reservoir 1 for storing an aqueous solution, an aerosol generator 2 for aerosolising the solution, and a controller 3 for controlling operation of the aerosol generator 2. The aqueous solution is fed from a reservoir 9 to the aerosol generator 2 along a delivery tube 13. In the invention aerosolised aqueous solution is entrained with insufflation gas. The gas is any suitable insufflation gas such as carbon dioxide. Other examples of suitable insufflation gases are nitrogen, helium and xenon.
The insufflation gas is delivered into an insufflation gas tubing 15 by an insufflator 12. The insufflator 12 may be of any suitable type such as those available from Karl Storz, Olympus and Stryker. The insufflator 12 has an outlet 20 through which insufflation gas is delivered. A bacterial filter 21 may be provided within the insufflator or, as illustrated, downstream of the insufflator outlet 20.
In this case a flow rate sensor/meter 11 is located in the flow path of the insufflation gas from an insufflator 12 to the aerosol generator 2. The flow rate sensor/meter 11 is connected by a control wire 70 to the controller 3, and the aerosol generator 2 is connected to the controller 3 by a control wire 16. The flow rate sensor/meter 11 may be a hot wire anemometer, or in the case where the flow is laminar or can be laminarised, a differential pressure transducer.
Sterile water may be used. In the case of an aqueous solution any suitable solution may be used. Solutions with a salt concentration in the range 1 μM (micro molar) to 154 mM (milli molar) (0.9% saline) are optimum as they cover the majority of medical applications. In addition, such saline concentrations can be readily nebulised using the aerosolisation technology used in the invention.
Aqueous solution may be stored in the reservoir 1 container of the nebuliser or the aqueous solution may be delivered to the reservoir 1 of the aerosol generator 2 in this case from the supply reservoir 9 along the delivery line 13. The flow of aqueous solution may be by gravity and/or may be assisted by an in-line flow controlling device 17 such as a pump and/or a valve which may be positioned in the delivery line 13. The operation of the flow controlling device 17 may be controlled by the controller 3 along a control wire 18 to ensure that the aerosol generator 2 has a supply of aqueous solution during operation. The device 17 may be of any suitable type.
The apparatus comprises a connector 30, in this case a T-piece connector 30 having an insufflation gas conduit inlet 31 and an outlet 32. The connector 30 also comprises an aerosol supply conduit 34 for delivering the aerosol from the aerosol generator 2 into the insufflation gas conduit 15 to entrain the aerosol with the insufflation gas, passing through the gas insufflation conduit 15. The entrained aerosol/insufflation gas mixture passes out of the connector 30 through the outlet 32 and is delivered to the body cavity along a line 60.
The aerosol supply conduit 34 and the insufflation gas conduit meet at a junction. Referring particularly to
The nebuliser (or aerosol generator), has a vibratable member which is vibrated at ultrasonic frequencies to produce liquid droplets. Some specific, non-limiting examples of technologies for producing fine liquid droplets is by supplying liquid to an aperture plate having a plurality of tapered apertures extending between a first surface and a second surface thereof and vibrating the aperture plate to eject liquid droplets through the apertures. Such technologies are described generally in U.S. Pat. Nos. 5,164,740; 5,938,117; 5,586,550; 5,758,637; 6,014,970, 6,085,740, and US2005/021766A, the complete disclosures of which are incorporated herein by reference. However, it should be appreciated that the present invention is not limited for use only with such devices.
In use, the liquid to be aerosolised is received at the first surface, and the aerosol generator 2 generates the aerosolised first fluid at the second surface by ejecting droplets of the first fluid upon vibration of the vibratable member. The apertures in the vibratable member are sized to aerosolise the liquid by ejecting droplets of the liquid such that the majority of the droplets by mass have a size of less than 5 micrometers. The vibratable member 40 could be non-planar, and may be dome-shaped in geometry.
Referring particularly to
The first surface of the vibratable member 40, which in use faces upwardly, receives the liquid medicament from the reservoir 1 and the aerosolised medicament, is generated at the second surface of the vibratable member 40 by ejecting droplets of medicament upon vibration of the member 40. In use the second surface faces downwardly. In one case, the apertures in the vibratable member 40 may be sized to produce an aerosol in which the majority of the droplets by weight have a size of less than 5 micrometers.
The complete nebuliser may be supplied in sterile form, which is a significant advantage for a surgical device.
Referring particularly to
The power source for the controller 3 may be an on-board power source, such as a rechargeable battery, or a remote power source, such as a mains power source, or an insufflator power source. When the remote power source is an AC mains power source, an AC-DC converter may be connected between the AC power source and the controller 3. A power connection lead may be provided to connect a power socket of the controller 3 with the remote power source.
Referring particularly to
Status indication means are also provided on the housing to indicate the operational state of the aerosol generator 2. For example, the status indication means may be in the form of two visible LED's, with one LED being used to indicate power and the other LED being used to indicate aerosol delivery. Alternatively one LED may be used to indicate an operational state of the aerosol generator 2, and the other LED may be used to indicate a rest state of the aerosol generator. 2.
A fault indicator may also be provided in the form of an LED on the housing. A battery charge indicator in the form of an LED may be provided at the side of the housing.
Referring particularly to
Referring particularly to
In use during laparoscopic surgery the flow of the insufflation gas into the abdomen of a patient is commenced to insufflate the abdomen. The flow rate sensor/meter 11 determines the flow rate of the insufflation gas. In response to the fluid flow rate of the insufflation gas, the controller 3 commences operation of the aerosol generator 2 to aerosolise the aqueous solution. The aerosolised aqueous solution is entrained with the insufflation gas, and delivered into the abdomen of the patient to insufflate at least part of the abdomen.
In the event of alteration of the fluid flow rate of the insufflation gas, the flow rate sensor/meter 11 determines the alteration, and the controller 3 alters the pulse rate of the vibratable member of the nebuliser accordingly.
The controller 3 is in communication with the flow rate sensor/meter 11. The controller 3 is configured to control operation of the aerosol generator 2, responsive to the fluid flow rate of the insufflation gas and also independent of the fluid flow rate of the insufflation gas as required.
In one case, the controller 3 is configured to control operation of the aerosol generator 2 by controlling the pulse rate at a set frequency of vibration of the vibratable member, and thus controlling the fluid flow rate of the aqueous solutions.
The controller 3 may comprise a microprocessor 4, a boost circuit 5, and a drive circuit 6.
The drive frequency may be started and stopped as required using the microprocessor 4. This allows for control of flow rate by driving the nebuliser 2 for any required pulse rate. The microprocessor 4 may control the on and off times to an accuracy of milliseconds.
The nebuliser 2 may be calibrated at a certain pulse rate by measuring how long it takes to deliver a know quantity of solution. There is a linear relationship between the pulse rate and the nebuliser flow rate. This may allow for accurate control over the delivery rate of the aqueous solution.
The nebuliser drive circuit consists of the electronic components designed to generate output sine waveform of approximately 100V AC which is fed to nebuliser 2 causing aerosol to be generated. The nebuliser drive circuit 6 uses inputs from microprocessor 4 and boost circuit 5 to achieve its output. The circuit is matched to the impedance of the piezo ceramic element to ensure good energy transfer.
The aerosol generator 2 may be configured to operate in a variety of different modes, such as continuous, and/or phasic, and/or optimised.
For example, referring to
Referring to
In another case, referring to
Referring to
The drive frequency can be started and stopped as required by the microprocessor; this allows control of flow rate by driving the nebuliser for any required pulse rate. The microprocessor can control the on and off times with an accuracy of microseconds.
A nebuliser can be calibrated at a certain pulse rate by measuring how long it takes to deliver a known quantity of solution. There is a linear relationship between the pulse rate and that nebuliser's flow rate. This allows accurate control of the rate of delivery of the aerosolised aqueous solution.
The pulse rate may be lowered so that the velocity of the emerging aerosol is much reduced so that impaction rain-out is reduced.
Detection of when the aperture plate is dry can be achieved by using the fact that a dry aperture plate has a well defined resonant frequency. If the drive frequency is swept from 120 kHz to 145 kHz and the current is measured then if a minimum current is detected less than a set value, the aperture plate must have gone dry. A wet aperture plate has no resonant frequency. The apparatus of the invention may be configured to determine whether there is any of the first fluid in contact with the aerosol generator 2. By determining an electrical characteristic of the aerosol generator 2, for example the current flowing through the aerosol generator 2, over a range of vibration frequencies, and comparing this electrical characteristic against a pre-defined set of data, it is possible to determine whether the aerosol generator 2 has any solution in contact with the aerosol generator 2.
If an application requires a constant feed from a drip bag then a pump can be added in line to give fine control of the liquid delivery rate which can be nebulised drip by drip. The rate would be set so that liquid would not build up in the nebuliser. This system is particularly suitable for constant low dose delivery.
Referring now to
In another case there may be a common information bus between the insufflator 12 and the controller 3. The insufflator 12 would have information on the rate of flow that it is producing and would communicate this to the controller 3 and on to the nebuliser 2, thereby eliminating the need for the flowmeter 11. This would allow the invention to be backward compatible with a variety of types of insufflator.
Referring to
Humidity may be generated via the aerosolisation of any aqueous solution. Relative humidity in the 50-100% range would be optimum. The control module can generate a nebuliser output of any defined relative humidity percentage based on the insufflator flow. These solutions include any aqueous drug solution. Solutions with salt concentrations in the range 1 μM-154 mM would be optimum.
The use of the nebulizer to humidify the insufflation gas prior to entering the body will eliminate the need for the body to humidify the gas once it is inside the body, thereby minimizing body heat loss by internal evaporation.
The control in nebulizer output allows proportional delivery of the required amount of humidity according to the amount of insufflation gas entering the body. In addition this control of aerosolization rate will prevent overloading of the insufflation gas with aerosol which would obscure the surgeons view.
In addition to acting as a humidifying agent the nebulizer can also act to deliver any agent presented in an aqueous drug solution. The system facilitates delivery of, for example, pain-relief medications, anti-infectives, anti-inflammatory and/or chemotherapy agents in aerosol form to the body cavity. These therapeutic agents could also act as humidifying substances in their own right.
The liquid entrained in the insufflation gas may contain any desired therapeutic and/or prophylactic agent. Such an agent may for example be one or more of an analgesic, an anti-inflammatory, an anaesthetic, an anti-infective such as an antibiotic, or an anti-cancer chemotherapy agent.
Typical local anaesthetics are, for example, Ropivacaine, Bupivacaine and Lidocaine.
Typical anti-infectives include antibiotics such as an aminoglycoside, a tetracycline, a fluoroquinolone; anti-microbials such as a cephalosporin; and anti-fungals.
Anti-inflammatories may be of the steroidal or non-steroidal type.
Anti-cancer chemotherapy agents may be alkylating agents, antimetabolites anthracyclines, plant alkaloids, topoisomerase inhibitors, nitrosoureas, mitotic inhibitors, monoclonal antibodies, tyrosine kinase inhibitors, hormone therapies including corticosteroids, cancer vaccines, anti-estrogens, aromatase inhibitors, anti-androgens, anti-angiogenic agents and other antitumour agents.
The system of the invention can be used for precise controlled delivery of drug and/or humidity during insufflation. No heating is required. Consequently there is no risk of damage to drugs due to heating The system may be used to provide precise control over aerosol output can be exercised by utilising pulse rate control. The system may be used for targeted delivery of a range of drugs, thereby reducing systemic side effects. In addition the system provides alleviation of post-surgical pain experienced by the patient.
The system need not be located in the direct flow path of insufflation gas. In addition, minimal caregiver intervention during laparoscopic procedure is required. The system is small and compact and allows for integration with an insufflator.
The device of the invention can be used throughout the procedure carried out by a surgeon. The device ensures that humidity is actively controlled during the procedure and thus ensures that a surgeon's view is clear as fogging is avoided.
All parts of the device (except the controller and associated leads) are autoclavable which provides a significant advantage for a device used in surgery.
The invention is not limited to the embodiments hereinbefore described, with reference to the accompanying drawings, which may be varied in construction and detail.
The present application claims priority under 35 U.S.C. §119(e) to U.S. provisional patent application, U.S. Ser. No. 60/907,311, filed Mar. 28, 2007, which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60907311 | Mar 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12058255 | Mar 2008 | US |
| Child | 13071862 | US |
