This invention relates to an apparatus and method for cooling the brain.
Lowering body temperature is thought to lessen the damaging effects of stroke.
There is a need in the art for an improved brain cooling apparatus which is simple and fast to use in emergency when a patient is in danger of suffering brain damage, for example, following a stroke. It is also desirable to provide a brain cooling apparatus which can be reliably and speedily put into use without significant difficulty by paramedics or nurses in a First Aid situation without requiring intervention by a physician or surgeon.
In addition, there is a need for an improved method of effecting brain cooling in a patient who has suffered a stroke or is otherwise in danger of undergoing brain damage unless speedy medical intervention is applied. In particular, there is a need for a method of effecting controlled cooling of the brain which can be put into operation simply and without the need for complex apparatus or for undertaking difficult medical procedures.
The invention provides in one aspect an apparatus for cooling the brain comprising: a pernasal intubation tube having a proximal portion, a lumen extending from the proximal portion, a distal end for insertion through one of the nostrils of a patient requiring brain cooling, an inflatable occluder provided on a distal portion of the tube and in communication with the lumen for inflation by fluid supplied through the lumen thereby to occlude the nasopharynx of the patient behind the soft palate of the patient and to prevent passage of liquid between the nasal cavities and the mouth of the patient; a pressure device for application to the exterior of the nose of the patient so as to apply pressure to the angular vein of the patient thereby to increase venous blood flow to the patient's brain; and a coolant gas supply for supplying coolant gas to at least one of the nasal cavities of the patient.
In another aspect the invention provides a method of cooling the brain of a patient in danger of suffering brain damage comprising occluding the air passage leading from the nasal cavities to the mouth cavity of the patient behind the soft palate of the patient, applying pressure to an exterior part of the patient's nose so as to exert pressure on the angular vein of the patient thereby to increase venous blood flow to the patient's brain, and supplying a coolant gas to the nasal cavities of the patient. Such a method does not involve obstruction of the oropharynx or laryngopharynx and the patient can continue to breathe through his or her mouth with or without the aid of a respirator.
Conveniently in such a method the coolant gas is supplied through one of the patient's nostrils and discharged through the other nostril. The coolant gas can be supplied intermittently but is preferably supplied continuously.
Hence a particularly preferred method of cooling the brain of a patient suffering from a condition which could lead to brain damage comprises the steps of: providing a pernasal intubation tube having a proximal portion, a lumen extending from the proximal portion and a distal end, with an inflatable occluder provided on a distal portion in fluid communication with the lumen; introducing the distal end of the tube through one of the nostrils of the patient until the inflatable occluder lies in the nasopharynx behind the soft palate of the patient; inflating the inflatable occluder by supplying fluid through the lumen so as to occlude the nasopharynx of the patient in a region behind the soft palate of the patient, thereby to prevent passage of liquid between the nasal cavities and the mouth of the patient; applying pressure to an exterior part of the patient's nose so as to apply pressure to the angular vein of the patient thereby to increase venous blood flow to the patient's brain; supplying coolant gas to at least one of the nasal cavities of the patient; and allowing gas to exit through at least one of the patient's nostrils.
In the accompanying semi-diagrammatic drawings:
Certain embodiments of the present invention provide a novel, improved form of apparatus for cooling the brain of a patient who is at risk of suffering brain damage as a result of a trauma, such as a stroke. They may provide such apparatus which can be used in a First Aid context by paramedics and other emergency service workers in situations where a person has suffered a trauma, such as a stroke, in the course of his or her normal occupations. In addition, they may provide such apparatus which can be used quickly and safely under emergency situations without risk of causing damage to the lower part of the pharynx.
Embodiments of the invention may also provide a novel, improved method of effecting brain cooling which can be speedily put into effect and which causes efficient cooling of a patient's brain following a traumatic episode, such as a stroke.
There will now be described a preferred embodiment of an apparatus for cooling the brain in accordance with the invention, which is illustrated in the accompanying drawings. This embodiment comprises a pernasal intubator comprising a tube having a proximal portion, a lumen extending from the proximal portion, a distal end for insertion through one of the nostrils of a patient requiring brain cooling, an inflatable occluder provided on a distal portion of the tube and in communication with the lumen so as to permit inflation of the inflatable occluder by fluid supplied through the lumen thereby to occlude the nasopharynx of the patient behind the soft palate of the patient and to prevent passage of fluid, i.e. liquid or gas, between the nasal cavities and the mouth of the patient. It further comprises a pressure device for application to the exterior of the nose of the patient so as to apply pressure to the angular vein of the patient thereby to increase venous blood flow to the patient's brain. In addition, it comprises a coolant gas supply for supplying coolant gas to at least one of the nasal cavities of the patient.
Preferably the lumen is provided at its proximal end with a fluid connector for connection to a source or generator of pressurised fluid. Such a fluid connector can be adapted for connection to an inflation bulb, for example.
The lumen can have a closed distal end in which case an aperture or apertures is provided in the wall of the lumen in fluid communication with the inflatable occluder whereby introduction of fluid, either liquid or a gas, through the lumen causes inflation of the inflatable occluder.
The inflatable occluder conveniently comprises a first cuff secured in fluid tight fashion to a distal portion of the tube. Alternatively the inflatable occluder may comprise a balloon secured in fluid tight fashion to a distal portion of the tube. In this case the tube may have an open distal end located within the balloon. If desired, the tube may be provided with a subsidiary inflatable cuff positioned proximally upstream from the first cuff or balloon.
Any non-toxic gas or mixture of gases can be used as coolant gas. Preferably, however, the coolant gas is oxygen. The coolant gas is preferably supplied at a temperature of from about −50° C. to about +10° C. It can be supplied, for example, at a rate of from about 1 l/min to about 100 l/min (measured at 0° C. and at 1 bar).
The pressure device conveniently comprises a nasal clip. Preferably the pressure device is adapted for securement on the tube.
In addition, there is described a method of cooling the brain of a patient in danger of suffering brain damage which comprises occluding the air passage leading from the nasal cavities to the mouth cavity of the patient behind the soft palate of the patient, applying pressure to an exterior part of the patient's nose so as to exert pressure on the angular vein of the patient thereby to increase venous blood flow to the patient's brain, and supplying a coolant gas to the nasal cavities of the patient. Such a method does not involve obstruction of the oropharynx or laryngopharynx and the patient can continue to breathe through his or her mouth with or without the aid of a respirator.
Conveniently in such a method the coolant gas is supplied through one of the patient's nostrils and discharged through the other nostril. The coolant gas can be supplied intermittently but is preferably supplied continuously.
A particularly preferred method of cooling the brain of a patient suffering from a condition which could lead to brain damage comprises the steps of:
providing a pernasal intubator comprising a tube having a proximal portion, a lumen extending from the proximal portion, a distal end, and inflatable occluder provided on a distal portion in fluid communication with the lumen;
introducing the distal end of the tube through one of the nostrils of the patient until the inflatable occluder lies in the nasopharynx behind the soft palate of the patient;
inflating the inflatable occluder by supplying fluid through the lumen so as to occlude the nasopharynx of the patient in a region behind the soft palate of the patient, thereby to prevent passage of liquid between the nasal cavities and the mouth of the patient;
applying pressure to an exterior part of the patient's nose so as to apply pressure to the angular vein of the patient thereby to increase venous blood flow to the patient's brain;
supplying coolant gas to at least one of the nasal cavities of the patient; and
allowing gas to exit through at least one of the patient's nostrils.
The tube is inserted through the patient's nostril until the inflatable occluder lies behind the patient's soft palate and then the inflatable occluder is inflated so as to block the passage of gas and liquid between the patient's nasal cavities and the patient's mouth. In this way the oropharynx and laryngopharynx of the patient are left substantially unobstructed so that the patient can continue to breathe through the mouth either unaided or with the assistance of a respirator.
Inflation of the inflatable occluder may comprise supplying air under pressure through a second lumen in the pernasal intubation tube, for example, by an inflation bulb.
Coolant gas can be supplied to the patient's nasal cavities through a second tube inserted through the patient's same nostril as the pernasal intubator or, preferably, through the patient's other nostril. Alternatively the tube of the pernasal intubator can be provided with a second lumen for supply of coolant gas terminating at an orifice in the wall of the tube of the pernasal intubator disposed at a position such that, in use, it will lie within one of the patient's nasal cavities.
Conveniently the coolant gas is supplied from a suitable supply, such as a pressurised gas cylinder, and cooled as a result of adiabatic expansion or by passage of the gas through a cooling coil immersed in a cooling bath, such as an acetone/solid CO2 (dry ice) cooling bath or a refrigerated brine solution.
As already noted, gas is permitted to escape through one or other, or both, of the patient's nostrils. Accordingly it is necessary not to block at least one the patient's nostrils in use of the pernasal intubator.
It will normally be preferred that the temperature of the brain is monitored and that the coolant gas is introduced at a rate sufficient to maintain the temperature of the brain at between about 32° C. and about 35° C.
In the drawings the reference numerals indicate like parts throughout.
Referring to the drawings,
The illustrated apparatus includes a pernasal intubation tube 21 which has a lumen 22 that leads to an aperture 23 near a distal end 24 of tube 21. As illustrated the pernasal intubation tube 21 has been inserted through the patient's right nostril 3; however, it can alternatively be inserted though the patient's left nostril, if more convenient, perhaps as a result of the way that the patient is lying. Tube 21 carries an inflatable cuff 25 near its distal end 24 and aperture 23 lies within cuff 25. Tube 21 further has a proximal end 26 which is provided with an appropriate connection device (such as is shown in
Although the apparatus has been illustrated in the accompanying semi-diagrammatic drawings with the pernasal intubation tube 21 inserted through the patient's right nostril 3 (as shown in
In use of the illustrated apparatus for First Aid treatment of a patient in danger of suffering brain damage after a stroke (which is of course only one example of usages to which apparatus according to the present invention may be put), the patient will typically be lying, or made to lie, prone on his or her back or side. Having ensured that the patient is in an appropriate position, a paramedic or other medically qualified practitioner then inserts the pernasal intubation tube 21 through one of the patient's nostrils, for example, through the patient's left nostril 3, until its closed distal end 24 lies just below the patient's soft palate 5. The paramedic can then check visually through the patient's mouth 8 to confirm that the distal end 24 is in the correct position. Next the inflatable cuff 25 is inflated using, for example, an inflation bulb until inflatable cuff 25 occludes the nasopharynx 17. It will be noted that the oropharynx 19 remains substantially unobstructed so that the patient can continue to breathe through his or her mouth 8 either unaided or with the help of a respirator (not shown).
A typical inflation pressure for inflating cuff 25 is about 100 mb gauge (about 1.45 psig).
The second tube 29 is inserted in the patient's other nostril, for example, the left nostril 28.
Temperature sensors can be positioned in the patient's auditory canals or attached to the patient's neck or other areas of the head or body in order to monitor the patient's brain temperature. In addition the body temperature of the patient can be monitored with, for example, the aid of a rectal thermometer.
In a First Aid situation, once the pernasal intubation tube 21 and the second tube 29 are in place, the coolant gas supply can be turned on so as to cause coolant gas, for example, cold oxygen, to pass through second tube 29 into the patient's nasal cavities thereby cooling directly the lining of the nasal cavities 4 and 33 and also the blood in the subjacent arteries and veins.
It will be appreciated by those skilled in the art that the illustrated apparatus is simple and readily portable. It is thus well suited for use by paramedics or by persons with appropriate training in first aid, such as police officers, who are likely to be first on the scene when a person suffers a stroke in the course of his or her usual occupations. Insertion of the pernasal intubation tube 21 through one of the patient's nostrils 3 or 28 can be achieved quickly and simply without the need for any additional probe or special intubation device. Moreover it can readily be checked visually whether the distal end 24 is in the correct position behind the patient's soft palate 5 prior to inflation of cuff 25. Similarly insertion of the second tube 29 in the patient's other nostril 28 or 3 is likewise quick and simple.
In comparison with prior art techniques that involve lowering the temperature of the entire body, the various forms of apparatus and the methods described herein have the advantage that only localised lowering of temperature of the head region is effected in order to cause cooling of the brain.
If desired, an electric pump designed to produce and maintain a predetermined pressure may be used in place of an inflation bulb for the purpose of inflating cuff 25.
Any non-toxic gas or mixture of gases can be used as coolant gas for supply through tube 29. Preferably, however, the coolant gas is oxygen. The coolant gas is preferably supplied at a temperature of from about −50° C. to about +10° C. It can be supplied, for example, at a rate ranging from about 1 l/min to about 100 l/min (measured at 0° C. and at 1 bar). It can be supplied directly from a pressurised oxygen cylinder, the desired lowered temperature being achieved by virtue of adiabatic expansion of the oxygen as it emerges from the cylinder. If a lower temperature is desired, then the coolant gas can be passed through a coolant coil immersed in a cooling bath containing, for example, refrigerated brine or an acetone/solid CO2 (dry ice) mixture. Alternatively the coolant gas can comprise air which has been bubbled through liquid oxygen.
In the course of treatment of a patient to effect brain cooling, it may be desirable that the patient's brain temperature is reduced to a temperature of not less than about +30° C., preferably not less than about +32° C., e.g. about +32° C. to about +35° C. Such reduced brain temperature can be maintained, for example, for a period of a few hours up to several few days or even months. A typical period of treatment may involve maintaining such a reduced brain temperature for from about 24 hours to about 72 hours. After receiving First Aid to reduce the brain temperature in the event of a stroke or other trauma that could lead to brain damage, the patient can undergo further suitable treatment in a hospital environment to lower his or her body temperature, in addition to reducing his or her brain temperature by the method of the invention.
The materials of construction of the apparatus of the invention can be selected from among those conventionally used in the field of medical intubation devices. For example, pernasal intubation tube 21 can be made from a pliable semi-rigid, soft plastics material such as a medical grade of polyethylene, polypropylene, polyvinylchloride, or the like. If desired, the distal end of pernasal intubation tube 21 may be coloured, e.g. blue or green, so as to increase its visibility and make it easier for a paramedic or other appropriately trained person to check that it is correctly in position before cuff 25 is inflated. The distal tip 24 may also include a radiopaque material to facilitate its visualisation in X-ray photographs.
Inflatable cuff 25 can be made from any material conventionally used for manufacture of cuffs on intubation devices, such as a medical grade of a silicone rubber.
As shown in
As described with reference to
However, it is also envisaged that these two tubes may in some constructions be combined as separate lumens of a single tube.
It is also envisaged that, in certain embodiments, the coolant gas may be used to inflate the cuff 25 of the apparatus. In such constructions a single lumen tube may be used, with apertures formed in the wall of the tube. In the particular embodiment shown in
As described, cuff 25 is arranged to be inflated with air under pressure. However, it is also envisaged that it can alternatively be inflated using liquid under pressure. Hence it can be arranged for connection via an inlet tap or valve to a diffusion bag filled, for example, with a cold saline solution, the appropriate pressure being generated by elevating the bag to an appropriate height above the patient's head.
A connector such as that depicted in
In place of the wishbone shaped clip of
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US08/01090 | 1/28/2008 | WO | 00 | 11/16/2009 |
Number | Date | Country | |
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60897745 | Jan 2007 | US |