Abstract: A method and apparatus for monitoring and controlling interventional therapy is described, where the interventional therapy results in the destruction of tissue and the release of chemical markers. When interventional therapy results in destruction of a patient tissue, such as cancerous tissue, a variety of chemical markers may be released into the bloodstream. An in-vitro diagnostic (IVD) device may be used to measure the concentration of an analyte representing a marker and compare the measured concentration with a predetermined set point so as to monitor or control the procedure. The blood for the analysis may be obtained either inter-procedurally or intra-procedurally depending on the promptness of the effect being measured and the speed of measurement.

Abstract: A catheter is adapted to exchange heat with a body fluid, such as blood, flowing in a body conduit, such as a blood vessel. The catheter includes a shaft with a heat exchange region disposed at its distal end. This region may include hollow fibers which are adapted to receive a remotely cooled heat exchange fluid preferably flowing in a direction counter to that of the body fluid. The hollow fibers enhance the surface area of contact, as well as the mixing of both the heat exchange fluid and the body fluid. The catheter can be positioned to produce hypothermia in a selective area of the body or alternatively positioned to systemically cool the entire body system.

Abstract: Devices, systems, and methods treat cosmetic defects, and often apply cooling with at least one tissue-penetrating probe inserted through of the skin of a patient. The cooling may remodel one or more target tissue so as to effect a desired change in a composition of the target tissue and/or a change in its behavior. Exemplary embodiments of the cooling treatments will interfere with the nerve/muscle contractile function chain so as to mitigate wrinkles of the skin. Related treatments may be used therapeutically for treatment of back and other muscle spasms, chronic pain, and the like. Some embodiments may remodel subcutaneous adipose tissue so as to alter a shape or appearance of the skin surface.

Abstract: A cryoplasty catheter and method for preventing or slowing reclosure of a lesion following angioplasty. The cryoplasty catheter includes a shaft having proximal and distal ends and a dilatation balloon disposed at the distal end. An intake lumen and exhaust lumen are defined by the shaft to deliver coolant to the balloon and to exhaust or drain coolant from the balloon. The method in accordance with the present invention includes cooling a lesion to aid in remodeling the lesion through dilatation and/or freezing a portion of the lesion adjacent the dilatation balloon to kill cells within the lesion to prevent or retard restenosis.

Abstract: A cryosurgical instrument, in which a separator is installed in a central feeding lumen and/or in a cryotip to separate gaseous and liquid components of a cryogen.

Abstract: Methods and systems for detecting fluid egress, assessing lesion quality, determining tissue composition or structure, determining ice coverage of catheter tip and providing tissue contact assessment, by providing a catheter having a shaft with a proximal end portion and a distal end portion, the proximal end portion and the distal end portion define at least one fluid pathway therebetween with the shaft having a plurality of electrodes, positioning the catheter at a tissue treatment site, applying an electrical current between at least two of the plurality of electrodes, measuring impedance voltage between the at least two of the plurality of electrodes and, processing the measured impedance voltage caused by the applied electrical current to determine if fluid egress is present, to assess lesion quality, to determine tissue composition, ice cover of catheter tip, and to provide contact assessment.

Abstract: An Ultrasonic apparatus and method is provided for the selective and targeted removal of unwanted tissues. The apparatus and methods may utilize combinations of ultrasonic and cryogenic energy for the selective removal tissue. The apparatus generates and delivers to the tissue cryogenic and ultrasonic energy, either in combination or in sequence, provides resize ablation of unwanted tissue parts, and may be used on various body tissues including internal organs.

Abstract: A cryoprobe clamp for creating a lesion in a target tissue comprises a housing portion, a handle extending from the housing portion, a clamp assembly including a distal blade and a proximal blade structured for clamping a target tissue therebetween, a trigger mechanism positioned adjacent the handle and operably coupled to the clamp assembly, and an ablation tool extending between the housing portion and the clamp assembly. The distal blade includes receiving means structured to receive a distal portion of the ablation tool, and the proximal blade includes an outer frame surrounding an open window portion. Upon clamping the target tissue between the distal and proximal blades, a lesion formed by the distal end of the ablation tool is visible through the window portion of the proximal blade.

Abstract: The cryosurgical kit and method of use relates to the combined use of biodegradable, imageable, drug(s) carriers, vectors or microcapsules deposited into a target tissue region inside a body and the controlled cooling of the target tissue region. A minimally invasive method of treatment that applies a cooling device to a selected tissue region, uses a vibrating resonant frequency delivery device to inject drug(s) carriers (microcapsules) containing therapeutic and contrast agents into tissue region(s) submitted to cooling temperatures, successive real-time imaging of the microcapsule deposition and later detection of the progressive degradation of microcapsules with ultrasound imaging which provides estimation of sustained release rates and for planning re-dosing regimens. The thermosensitive microcapsules preferably contain ethiodol, a contrast agent for Ultrasound and/or X-Ray imaging, and cytotoxic drug(s).

Abstract: A surgical instrument for treating a tissue includes a handpiece and a tissue engaging portion arranged to be received by the handpiece. The tissue engaging portion includes first and second opposed jaw members having an open position and a closed position for engaging the tissue therebetween, where the first and second jaw members are arranged to receive surgical energy from a surgical generator. The tissue engaging portion further includes at least one cooling member spaced from at least one of the first and second jaw members, where the cooling member has an open position and a closed position for engaging the tissue. Positioning the jaw members in their closed position and applying surgical energy to the tissue allows for treatment of the tissue, and positioning the cooling member in its closed position provides at least one of a pressure gradient or a thermal gradient between the jaw members and the cooling member.

Abstract: The present invention provides minimally invasive imaging probe/medical device having a frictional element integrated therewith for reducing non-uniform rotational distortion near the distal end of a medical device, such as an imaging probe which undergoes rotational movement during scanning of surrounding tissue in bodily lumens and cavities.

Abstract: A cryoprobe for surgical and other treatments. The cryoprobe comprises an expandable section that performs displacement of a distal cryotip forwards when there is elevation of the operation pressure in the interior of the cryoprobe. Needle-wise metal elements are installed on the external side of the cryotip. These needle-wise elements are deflecting outwards by a deflecting member fastened on the distal edge of an external shaft of the cryoprobe. This allows a significant enlargement of the frozen volume of the treated tissue with the same operation temperature and the outer diameter of the cryoprobe. In another embodiment, the needle elements are formed in a displaceable metal sheath and a distal section of a cryotip and/or special protrusions on this distal section act as the deflecting member.

Abstract: A cryogenic applicator for rejuvenating skin and a treatment for use of the applicator. A barrel is hand-held. A head is rotatably mounted to the barrel. A cryogenic interface fluidly connects the barrel to a source of a biocompatible non-toxic cryogenic fluid to supply the cryogenic fluid through the barrel to the head that in turn sparges the cryogenic fluid onto the skin quickly, evenly, and smoothly when the head is rolled on the skin, and thereby rejuvenate the skin. The treatment includes the step of rolling the head quickly, smoothly, and evenly over the skin being treated for a period of time in an order of hundredths or tenths of a second, and sparging the cryogenic fluid onto the skin quickly, evenly, and smoothly when the head is rolled on the skin, and thereby rejuvenate the skin.

Abstract: The sensor device has a housing. The housing is made of a material having a first high heat-conductivity index. A holder is attached to the housing and made of a material with a second low heat-conductivity index that is substantially lower than the first high heat conductivity index. The holder holds a peltier element and is connected to a power source so that the element has a cooled layer and a heated layer. A rotatable roller is in operative engagement with the layer so that the layer cools the roller. The roller may be rolled on the skin of the patient to determine the scope and effect of anesthetic treatment.

Abstract: A device includes a handpiece having a probe tip disposed at an end thereof, and, connected to the handpiece such that, at the probe tip, a functionality of each is provided, a plurality of optical coherence tomography (OCT) probes.

Abstract: A cryogenic medical system includes a medical device and a console connectable to the medical device at a connection point. The console controls the temperature of the medical device. The console includes a first cooling system directing coolant to the medical device at a first temperature along a coolant supply line and a second cooling system chilling the coolant within the coolant supply line to a temperature below the first temperature before the coolant reaches the connection point.

Abstract: A spray of cryogen is patterned to create a pattern of cooled regions on a target tissue for cosmetic dermatological treatment. In one embodiment, the cryogen is patterned using a heated mask. An optical source is configured to irradiate the target tissue in a region at least partially overlapping the cooled regions to create a pattern of treatment zones. A control unit adjusts the timing of between the cryogen and optical pulses.

Abstract: A cryosurgical instrument for separating a tissue sample from a biological tissue to be treated, for purposes of biopsy. The cryosurgical instrument includes a probe for bringing a probe head up to the biological tissue and a gas line for supplying cooling gas from a gas source of a cryosurgical apparatus to the probe head. The probe head cools a limited tissue region, by means of the supplied gas, for obtaining a tissue sample. The tissue sample can be separated from the surrounding tissue when frozen onto the probe head. The instrument has a support tube in which the probe is guided and which can be moved relative to the probe in such a way that the surrounding tissue can be supported by means of the support tube during the separating of the tissue sample. The instrument also includes an accelerating device that provides a predefined force for the separating process.

Abstract: Methods for diagnosing skin lesions are disclosed. Generally, the method include topically administering an IRM compound to a treatment area for a period of time and in an amount effective to cause a visible change in the appearance of a skin lesion including, in some cases, causing subclinical lesions to become visible. Suitable IRM compounds include agonists of one or more TLRs.

Abstract: Methods and apparatus for cryo-therapy are disclosed herein. This includes a hollow guidewire disposed within a catheter having helical loops contacting tissue. A coolant delivery tube disposed within can have a coolant delivered from a proximal end into the guidewire lumen. The coolant flows back proximally through the guidewire while cooling the guidewire surface and cooling or cryogenically ablating the contacting tissue. To minimize guidewire exposure to surrounding fluids or tissue, insulative barriers can be attached to the guidewire. A coolant delivery tube and return lumen can be integrated from a single extrusion in various configurations. Expandable balloons can also be used to expand the loops of the guidewire to contact the tissue. Also, helical loops with a coolant delivery tube or stem disposed longitudinally within the loops can be used and the loops can also have a variable collapsible cooling region.

Abstract: A cryogenic catheter includes an outer flexible member having at least one cryogenic fluid path through the flexible member. The at least one fluid path is defined by a plurality of flexible members disposed within the outer flexible member.

Abstract: The disclosure describes medical mats that provide electrical paths with connectors that connect to various electronic medical or surgical tools. The medical mats can reduce the lengths of cables and define routes that preventing cross-over, looping and/or bunching of loose lengths of long cables.

Abstract: The present invention provides a surgical device including an elongate body defining a fluid flow path therethrough. An expandable element may be coupled to the elongate body and placed in fluid communication with the fluid flow path. Moreover, the surgical device may include a first leak detection element at least partially surrounding a portion of the expandable element, and a second leak detection element may be provided in fluid communication with the fluid flow path. In addition, a console may be provided, where the console may be in communication with the first and second leak detection elements. Further, a supply of cryogenic fluid as well as a vacuum source may be provided in fluid communication with the fluid flow path.

Abstract: Devices, systems, and methods treat cosmetic defects, and often apply cooling with at least one tissue-penetrating probe inserted through of the skin of a patient. The cooling may remodel one or more target tissue so as to effect a desired change in a composition of the target tissue and/or a change in its behavior. Exemplary embodiments of the cooling treatments will interfere with the nerve/muscle contractile function chain so as to mitigate wrinkles of the skin. Related treatments may be used therapeutically for treatment of back and other muscle spasms, chronic pain, and the like. Some embodiments may remodel subcutaneous adipose tissue so as to alter a shape or appearance of the skin surface.

Abstract: A system and methods for modeling the death of tissue cells that are thermally treated using thermal treatment devices is disclosed. A cell-death model accurately predicts, in real-time, which voxels of cells are dead or are about to die as the thermal treatment is applied to these cells. The effects of thermal treatment are monitored by a thermal measurement device which feeds thermal information to the cell-death model. The cell-death model accounts for the temperature of each voxel of tissue cells with respect to a temperature threshold value and the duration over which the thermal treatment is applied. When the thermal measurement device is an imaging device, the results of the thermal treatment may be displayed to the user in real-time. As a result, a user of the thermal treatment device can determine, in real-time, which target voxels of cells he has killed and which still need to be killed. The user can also more easily avoid inadvertently killing healthy tissue that he does not intend to kill.

Abstract: The present invention relates to a probe-insertion guiding apparatus for guiding a user towards correct insertion of therapeutic probes into a patient. The apparatus comprises a template which comprises a plurality of apertures sized to accommodate therapeutic probes and to guide insertion of such probes into a body, a probe command receiver for receiving probe insertion commands specifying template apertures through which probes are to be inserted, and at least one of a) a sensory output device operable to indicate to a user which aperture is to receive a next inserted probe, and b) a probe detection device operable to detect insertion of a probe into an aperture. Preferred embodiments include feedback modules providing feedback to a user indicating whether the user's probe did or did not correspond to a probe insertion specified by a received probe insertion command.

Abstract: A cryosurgery device includes an aerosol container holding a liquid refrigerant and having a valve and a stem extending out therefrom; an actuator seated on the stem and including an outlet tube for receiving released refrigerant from the container; a hub mounted on the container and including slots therein; and a base having a central opening for receiving the hub, the base including aligning projections that enter the slots in the hub to engage and apply pressure to the actuator to cause the actuator to depress the stem and release refrigerant into the base. The container may further contain an applicator tube mounted to the hub in fluid communication with the outlet tube with a porous tip mounted to a distal end of the applicator tube for receiving the refrigerant and, being chilled thereby, applied to a skin lesion to be treated.

Abstract: The present invention provides a system for achieving erythema and/or mild edema in an upper layer of skin, without causing blisters, and without the risk of high fluence levels or critical need for cooling.

Abstract: A method is disclosed for treating heart and vascular tissue with cryotreatment. A medical instrument, such as a catheter is positioned to contact a target region of cardiac tissue such as the epicardial tissue. The instrument or catheter provided includes a cryotreatment element that has thermally-transmissive properties. The cryotreatment element may be a cryochamber for enclosing the flow of a fluid refrigerant therein. The cryotreatment element is disposed at the situs of heart or vascular tissue to be treated, usually by piercing the epicardium sac via an opening in the patient's body. A refrigerant flow within the cryochamber creates endothermic cooling with respect to the targeted heart or vascular tissue, inducing hypothermia and forming iceballs proximate the tissue. The cooling may be reversible and non-permanent, or may be permanent leading to cell death, necrosis, apoptosis and/or surgical excision or ablation of tissue.

Abstract: An engine comprises a liquid piston disposed within a chamber of an engine body. The chamber is defined by at least one wall. The liquid piston has one or more free surfaces that are not in contact with the chamber wall. A laser directly heats the free surface of the liquid piston. A gas spring is disposed within the chamber adjacent the free surface of the liquid piston and within the propagation path of the laser energy. The engine also includes a spring mechanism. The spring mechanism is positioned within the housing to exert pressure on another surface of the liquid piston.

Abstract: A device for biopsy of body tissue. The device is driven by liquid CO2, and is provided with a control system to control various components to effectuate rotating core biopsies.

Abstract: A cryosurgical probe that is operative to bring target nerve tissue to a temperature below about ?140° C. so as to reduce or eliminate regeneration of the nerve tissue by growing an ice ball. The probe comprises a thermally conductive body, a thermally insulating body and a temperature sensor. The thermally conductive body has a conductive portion adapted to contact the tissue and form an ice ball thereat during use. The thermally insulating body is adjacent to the conductive portion onto which the ice ball forms during use. The temperature sensor is positioned at a predetermined position on the thermally insulating body with respect to the conductive portion. The predetermined position corresponds to a predetermined size of the ice ball grown in the tissue when the sensor reads a predetermined temperature. The insulating body provides sufficient thermal insulation between the conductive body and the surrounding tissue so that the sensor detects freezing of.

Abstract: Devices, systems, and methods efficiently dilate and/or cool blood vessels and other body tissues. Controlled cooling with balloon catheters and other probes may be effected by a change in phase of a cryogenic fluid, often after measuring a minimum pulse width for actuating an individual solenoid valve along the cooling fluid path, with the measured pulse width allowing gradual inflation of a balloon without excessive venting of cooling fluid.

Abstract: A catheter having an extended treatment zone for cooling tissue is provided. The catheter includes an elongate catheter body having a distal tip, and a fluid injection conduit disposed inside the catheter body defining a return lumen therein. The fluid injection conduit further defines two or more injection orifices including a first distal orifice near the distal tip, and a second orifice longitudinally offset along the fluid injection conduit to be less proximate the distal tip than the first orifice. Fluid cryogen flowing through the orifices creates an extended tissue cooling contour about the distal end portion of the catheter. At least one ECG ring electrode is provided about the catheter body near the second orifice. The catheter may thus provide for electrocardiographic mapping of tissue nodes lying transversely between the distal tip and the ECG ring electrode.

Abstract: Probe based low temperature lesion formation apparatus, systems and methods include, in one embodiment, a surgical probe having a relatively short shaft (e.g. between 3-12 cm) defining a distal portion and a proximal portion, an inflatable cryogenic element, defining an exterior surface, associated with the distal portion of the shaft; and at least one temperature sensor on the exterior of the inflatable cryogenic element. In another embodiment, a method of forming a lesion in a tissue structure includes the steps of positioning an inflatable cryogenic element on the tissue structure with a temperature sensor between a portion of the inflatable cryogenic element and a portion of the tissue surface, supplying cryogenic fluid to the inflatable cryogenic element, maintaining pressure within the inflatable cryogenic element below about 100 mm Hg, and measuring tissue temperature with the temperature sensor.

Abstract: An ultrasonic apparatus and method is provided for the selective and targeted removal of unwanted tissues. The apparatus and methods may utilize combinations of ultrasonic and cryogenic energy for the selective removal tissue. The apparatus generates and delivers to the tissue cryogenic and ultrasonic energy either in combination or in sequence, provides resize ablation of unwanted tissue parts, and may be used on various body tissues including internal organs.

Abstract: Procedures, techniques, and systems for in vivo monitoring, diagnosis, and treatment of tissue during the same or concomitant medical procedure. In disclosed embodiments, during a same or concomitant procedure or examination, tissue can be scanned on a localized level using a real-time optical biopsy system. The real-time optical biopsy system may involve angle-resolved and/or Fourier domain low coherence interferometry (LCI). Because the scanning can be performed in real-time, diagnosis can also be performed in real-time and during the same or concomitant medical procedure. As a result, therapy, if needed, can also be administered to the tissue during the same or concomitant medical procedure. Monitoring of the tissue after therapy can be performed during the same or subsequent procedure.

Abstract: An ablative apparatus that can be used to treat atrial fibrillation and other cardiac arrhythmias by ablating cardiac tissue is disclosed. When the distal end of the apparatus reaches the tissue to be ablated, an ablation probe driven by a transducer is vibrated. Scratching the tissue with abrasive members, the vibrating ablation probe is capable of mechanically ablating tissues. This mechanical ablation may be utilized to penetrate epicardial fat, thereby exposing the underlying myocardium. The ablative apparatus may then be used subject the exposed myocardium to mechanical ablation, cryoablation, ultrasonic ablation, and/or any combination thereof.

Abstract: A cryosurgical probe system includes a fluid supply line connectable at an inlet section to a source of cryogenic fluid; a fluid connector assembly securely connected to an outlet section of the fluid supply line for receiving fluid from the outlet section of the fluid supply line; and, a detachable cryosurgical probe detachably connectable to the fluid connector assembly. The cryosurgical probe system includes the capability of providing return fluid flow.

Abstract: A cryotherapy system is provided with multiple cryoprobes, each of which has a shaft with a closed distal end adapted for insertion into a body and conduits for flowing a cryogenic fluid through the shaft to reduce a temperature of the distal end. A source is provided for the cryogenic fluid, and flow-control metering valves are provided in fluid communication with the conduits and source of the cryogenic fluid. A compressor is provided in fluid communication with the conduits of the cryoprobes to define a self-contained fluid system. The flow-control metering valves and the compressor are controlled by a computer processor to provide the desired flows of the cryogenic fluid through the conduits of the self-contained fluid system.

Abstract: A device is described that can be used quickly and accurately by surgeons to provide uniform facial tissue planes that are tunnel-free and wall-free thus optimizing face lifting, tightening, and implant delivery. The device is comprised of a shaft with a substantially planar tip further comprised of relative protrusions and energized relative recession lysing segments. Forward motion of the device precisely divides and energizes various tissue planes causing contraction, especially via the fibrous tissues. Other forms of energy and matter can be delivered down the shaft to further enhance desirable tissue modification and contraction.

Abstract: A cryosurgical probe system includes a fluid supply line connectable at an inlet section to a source of cryogenic fluid; a fluid connector assembly securely connected to an outlet section of the fluid supply line for receiving fluid from the outlet section of the fluid supply line; and, a detachable cryosurgical probe detachably connectable to the fluid connector assembly. The cryosurgical probe system includes the capability of providing return fluid flow.

Abstract: A system for applying therapy to an eye selectively applies coolant to the corneal surface to minimize heat-related damage to the corneal surface during thermokeratoplasty. Embodiments may include an energy source, a conducting element, a coolant supply, and at least one coolant delivery element. The conducting element is operably connected to the energy source and extends from a proximal end to a distal end. The conducting element directs energy from the energy source to the distal end, which is positionable at the eye. The coolant delivery elements are in communication with the coolant supply and are operable to deliver a micro-controlled pulse of coolant to the distal end.

Abstract: An apparatus and method for protecting the neurovascular bundle during cryoablation of tissues of the prostate by heating the vicinity of the neurovascular bundle while cooling pathological tissues of a prostate to cryoablation temperatures, thereby cryoablating pathological tissues while protecting the neurovascular bundle from damage. A cryoprobe operable to cool a distal operating tip while heating a proximal shaft is presented.

Abstract: An apparatus and method for shielding non-target tissues and organs during thermotherapy, brachytherapy or other treatment of a diseased target tissue. The apparatus includes a catheter shaft having input and output lumens and at least one inflatable balloon. A plurality of input lumens within the catheter shaft allows the passage of liquid or gas through an input port and into the interior of the balloon thereby inflating the balloon. The gas or liquid can then be cycled through the inflated balloon through an output port and output lumen and out of the catheter shaft. Temperature sensors or other sensors may be attached to the balloon or catheter to monitor temperature or other conditions at the treatment site. The catheter is positioned between the target tissue or organ and sensitive non-target tissues in proximity to the target tissue and inflated causing a physical separation of tissues as well as a physical shield.

Abstract: Devices and methods provide for ablation of cardiac tissue for treating cardiac arrhythmias such as atrial fibrillation. Although the devices and methods are often be used to ablate epicardial tissue in the vicinity of at least one pulmonary vein, various embodiments may be used to ablate other cardiac tissues in other locations on a heart. Devices generally include at least one tissue contacting member for contacting epicardial tissue and securing the ablation device to the epicardial tissue, and at least one ablation member for ablating the tissue. Various embodiments include features, such as suction apertures, which enable the device to attach to the epicardial surface with sufficient strength to allow the tissue to be stabilized via the device. For example, some embodiments may be used to stabilize a beating heart to enable a beating heart ablation procedure. Many of the devices may be introduced into a patient via minimally invasive introducer devices and the like.

Abstract: A catheter is provided with an anchoring member for anchoring a part of a linear ablating head of the catheter to a structure. The structure can be a cryogenically anchored point catheter. This allows the surgeon to position the linear catheter more exactly in the heart chamber and overcomes the adverse effects of the slippery and irregular heart chamber walls.

Abstract: The invention relates to a coolant dosing device for the application of cryogenic gas for producing low temperatures as required e.g. in cryosurgery. The invention aims to ensure a disturbance-free operation in spite of often dirty gas and to exclude possible operating errors in the connection of capsules of the prior art. According to the invention, the coolant dosing device comprises a capillary tube that receives gas that has been filtered in the capsule and directly supplies it to the dispenser, thereby ensuring a disturbance-free operation. The low force connection between the capsule and the metering device by means of O-rings that are slipped over ensures a tight seal and an error-free operation.

Abstract: Cardiac ablation systems and methods of their use and manufacture involve an ablation mechanism, a stabilizer mechanism, and a cinching mechanism that urges the ablation mechanism toward a patient tissue. Embodiments encompass methods for administering epicardial and endocardial lesions, including box lesions and connecting lesions, to patient tissue.

Abstract: A catheter-based system for performing a cryoablation procedure uses a precooler to lower the temperature of a fluid refrigerant to a sub-cool temperature (?40° C.) at a working pressure (400 psi). The sub-cooled fluid is then introduced into a supply line of the catheter. Upon outflow of the primary fluid from the supply line, and into a tip section of the catheter, the fluid refrigerant boils at an outflow pressure of approximately one atmosphere, at a temperature of about ?88° C. In operation, the working pressure is computer controlled to obtain an appropriate outflow pressure for the coldest possible temperature in the tip section.