Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M16/00—Devices for influencing the respiratory system of patients by gas treatment, e.g. mouth-to-mouth respiration; Tracheal tubes
  • A61M16/04—Tracheal tubes
  • A61M16/0434—Cuffs
  • A61M16/044—External cuff pressure control or supply, e.g. synchronisation with respiration

Definitions

• the invention concerns a respiration catheter of the type stated in the introductory portion of claim 1.
• a respiration catheter is known from DK-C-111149.
• Endotracheal tubes intended for insertion through the mouth, nose or implanted in the neck are usually provided with an inflat ⁇ able cuff for sealing against the tracheal wall.
• the efficiency of the sealing is determind by the magnitude of the cuff pressure against the tracheal wall since the inflated cuff does not seal off pressures exceeding the pressure of the cuff against the wall.
• the air pressure in the cuff determines the pressure against the tracheal wall.
• the pressure of the cuff against the tracheal wall can be controlled and regulated only if the cuff has a sufficiently large diameter to make contact with the tracheal wall without any stretching of the sheet material of the cuff, i.e. the cuff must be lying folded on the tracheal wall. If this demand is met, the pressure in the cuff is identical with its pressure on the wall.
• the sealing cuff has the additional function of preventing liquid (blood, saliva, vomit) from flowing past the cuff down into the lungs. It has been found that this function is accomplished when the pressure of the sealing cuff against the tracheal wall is at least 20 to 30 cm H 2 0.
• the necessary pressure of the respiration air may often exceed 20 to 30 cm H ⁇ 0, and the pressure in the sealing cuff is then too low to seal off the pressure of the respiration air.
• the respiration catheter described in DK-C-111149 is equipped with a two-way cut-off valve mounted on the air supply tube for the sealing cuff.
• closing and opening of the valve are controlled by the pressure changes in the external opening of the catheter tube which are produced during artifical respiration.
• the cut-off valve closes so that the air in the sealing cuff cannot escape through the air supply tube, and the pressure increase in the tracheal tube is transferred to the sealing cuff, the air in the sealing cuff being com- pressed so that the sealing cuff can seal off the pressure prevailing in the trachea.
• the cut-off valve opens again, providing free connection between the source of compressed air and the sealing cuff, which then remains inflated by the constant, regulated pressure of 20 to 30 cm H tripod0.
• the respiration catheter according to DK-C-111149 has the closing valve arranged in a respiration air supply tube at the external opening of the catheter. Due to the flow resistance between the two ends of the catheter and the consequent difference in pressure, the valve closes prematurely during inflation and opens prematurely during expiration. This entails that part of the air in the sealing cuff escapes during the expiration phase so that, for a short moment, the cuff cannot provide an efficient sealing of the trachea.
• the object of the invention is to provide an embodiment of a respiration catheter of the present type which prevents the said malfunction involving the risk of liquid flowing past the sealing cuff down into the lungs.
• respiration catheter is constructed as stated in the characterizing portion of claim 1 since, in this structure, a pressure drop in the catheter tube cannot at any time cause premature opening of the closing valve and, consequently, neither undesir ⁇ able escape of air from and thereby defective sealing capacity of the cuff.
• one of the two supply tube parts of this struc ⁇ ture may be used for sucking luquid which accumulates above the sealing cuff.
• Claim 5 defines a simple and inexpensive embodiment of the cut-off valve.
• a valve When such a valve is arranged on the outer side of the catheter tube, movement of this tube into contact with the tracheal wall may cause unintended closing of the valve.
• This drawback may be avoided by con- stru ⁇ ting the valve as stated in claim 6, so that the air may follow the long way round in case the short path between the two openings is obstructed.
• respiration catheter of the invention is shown schematically in the drawing partly in longitu ⁇ dinal section, fig. 1, partly in cross section, fig. 2, along the line II-II in fig. 1, and will be described more fully below with reference to the drawing.
• 10 is the end of a catheter tube intended for introduction into a patient's trachea.
• a sealing cuff 12 which is made of a thin, preferably inelastic sheet material and encircles the tube.
• Compressed air can be supplied to the cuff through a tubing system consisting of two channels 13 and 14, which are provided in the wall of the catheter tube 10, and which are both closed by a plug 15 and 16, respectively, at the end of the tube 10.
• One channel 13 can be connected through a tube 17 to a source of compressed air (not shown) which delivers air with a substantially constant pressure, which may e.g. be of the order of 20 to 30 cm H O.
• each of the channels 13 and 14 is provided with a hole 19 and 20, respectively, opening to the outside of the catheter tube, and these holes are covered by a rectangular piece 31 of sheet, which is welded along the edges to the catheter tube 10 and thus forms a valve which, controlled by the pressure conditions, can estab- lish connection between the two holes 19 and 20 and inter ⁇ rupt this connection.
• the channel 14 communicates with the interior of the cuff 12 through another hole 22 positioned between the hole 20 and a plug 18.
• This channel additio ⁇ nally has a third hole 23 which is positioned immediately beyond the end of the cuff 12 facing away from tube end 11 and such that the plug 18 will be situated between the holes 22 and 23. This hole 23 opens to the outer side of the catheter tube 10.
• the respiration catheter of the invention ensures effective sealing against the tracheal wall under all circumstances, also in case of lungs of low compliance requiring a high respiration pressure, and also ensures full perfusion of the tracheal wall since the engagement pressure is below the value which may cause damage, except for short moments.
• the part of this channel positioned between the cuff 12 and the free end (not shown) of the channel 14 may be used for sucking liquid from the space between the catheter tube and the patient's trachea by connecting the free end with a suitable suction means (not shown).
• a sheet ring may optionally be used, surrounding the catheter tube and welded to the tube along the edges. This establishes two paths between the holes 19 and 20, and if the short path is blocked, e.g. in that the catheter tube engages the tracheal wall, air may pass the long way round the circumference of the catheter tube.
• Another possibility is to arrange the holes 19 and 20 in the inwardly facing side of the channels 13 and 14 so that they open to the interior of the catheter tube, and consequently place the sheet 21 on the inner side of the catheter tube.
• the cut-off valve may also be constructed differently from what is described above and may e.g. be formed by a sleeve or bladder of thin sheet material which connects the two ends of the channels 13 and 14 with each other. Also the shape and position of the channels may differ from what is shown and described.

Landscapes

• Health & Medical Sciences (AREA)
• Pulmonology (AREA)
• Emergency Medicine (AREA)
• Engineering & Computer Science (AREA)
• Anesthesiology (AREA)
• Biomedical Technology (AREA)
• Heart & Thoracic Surgery (AREA)
• Hematology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Media Introduction/Drainage Providing Device (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8089611

Family Applications (1)

Country Status (5)

Cited By (1)

Citations (2)

• 1990
  • 1990-01-12 DK DK8990A patent/DK163641C/da not_active IP Right Cessation
• 1991
  • 1991-01-11 WO PCT/DK1991/000010 patent/WO1991010464A1/en active IP Right Grant
  • 1991-01-11 DE DE69126217T patent/DE69126217T2/de not_active Expired - Fee Related
  • 1991-01-11 ES ES91902859T patent/ES2103000T3/es not_active Expired - Lifetime
  • 1991-01-11 EP EP91902859A patent/EP0592397B1/en not_active Expired - Lifetime

Patent Citations (2)

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