Methods and devices for minimally invasive respiratory support

• US 20080135044A1
• Filed: 08/03/2007
• Published: 06/12/2008
• Est. Priority Date: 06/18/2003
• Status: Active Grant

• Current Assignee: Breathe Technologies, Inc. (Baxter International Inc.)
• Original Assignee: Breathe Technologies, Inc. (Baxter International Inc.)
• Inventors: Wondka, Anthony, Kapust, Gregory, Bryan, Robert, Freitag, Lutz, Gerber, Anthony, Khenansho, Michael
• Granted Patent: US 8,381,729 B2
• Time in Patent Office: Days
• US Class Current: 128/200.26
• CPC Class Codes: A61M 16/101 using an oxygen concentrator
• CPC Class Codes: A61M 16/107 in the inspiratory path
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 2202/0007 introduced into the body
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2202/03 Gases in liquid phase, e.g. cryogenic liquids

Abstract

Modes, methods, systems and devices are described for providing assisted ventilation to a patient, including wearable ventilation systems with integral gas supplies, special gas supply features, ventilation catheters and access devices, and breath sensing techniques.

Claims

1. A ventilatory support apparatus, comprising:

a ventilator;

a ventilation gas delivery catheter adapted for connection to the ventilator;

a breath sensor in communication with the ventilator; and

an integrated ventilation gas reservoir to store a quantity of ventilation gas and integrated in the ventilator.

156. A method as in claim 1 wherein the pressure or flow rate amplitude of the ventilation gas delivery is adjustable.

2. A ventilatory support apparatus, comprising:

(a) a ventilator;

(b) a catheter adapted to be indwelling in a patient'"'"'s airway;

(c) a sensor adapted to be located in the patient'"'"'s airway to measure tracheal airflow; and

(d) a ventilation gas source,

wherein a volume of ventilation gas is adapted to be delivered at a rate synchronized with the patient'"'"'s spontaneous breathing and delivered during the patient'"'"'s inspiratory phase.

3. An apparatus as in claim 2 wherein the ventilator is configured to be worn by the patient.

4. An apparatus as in claim 2 wherein the ventilator includes an integrated supply of oxygen volume.

5. An apparatus as in claim 2 wherein the ventilator includes an integrated supply of liquid oxygen and means to convert the liquid oxygen into gaseous oxygen.

6. An apparatus as in claim 2 wherein the ventilator includes an integrated oxygen generating system.

7. An apparatus as in claim 2 wherein the ventilation gas volume to be delivered is 5-50% of a patient'"'"'s natural tidal volume.

8. An apparatus as in claim 2 wherein a ventilation gas driving pressure is 5-25 psi.

9. An apparatus as in claim 2 wherein a ventilation peak flow rate delivery is 15-35 liters per minute.

10. An apparatus as in claim 2 wherein a ventilation gas delivery time is 0.1 to 0.8 seconds.

11. An apparatus as in claim 2 wherein the catheter includes a catheter tip and a ventilation gas exit speed out of the catheter tip is 25-250 meters per second.

12. An apparatus as in claim 2 wherein ventilation gas exit airflow dynamics are selected to cause 10-100% volume entrainment of gas from an upper airway into a lung with the ventilation gas.

13. An apparatus as in claim 2 wherein a ventilation gas delivery amplitude is selected to cause a less negative pressure in a patient'"'"'s lung during inspiration compared to a negative pressure during un-assisted breathing.

14. An apparatus as in claim 2 wherein a ventilation gas delivery amplitude is selected to cause a positive pressure in a patient'"'"'s lung during inspiration compared to a negative pressure during un-assisted breathing.

15. An apparatus as in claim 2 wherein the breath sensor comprises two individual sensors used to obtain a comparison between the two individual sensors wherein a comparison is used to compensate for drifts and signal artifacts.

16. An apparatus as in claim 15 wherein the individual sensor comparison is differentiated to correlate the signal to different parts of the breathing curve.

17. An apparatus as in claim 2 wherein the ventilation gas source is a liquid oxygen system.

18. An apparatus as in claim 2 wherein the ventilation gas source is a compressed oxygen gas source.

19. An apparatus as in claim 2 wherein the ventilation gas source is an oxygen generating system.

20. An apparatus as in claim 2 wherein the sensor comprises means to measure the strength and direction of tracheal airflow to deliver the ventilation gas after the inspiratory flow rate reaches a peak amplitude.

21. An apparatus as in claim 2 wherein the sensor signal is correlated to respiratory muscle activity to provide means to deliver the ventilation gas after respiratory muscles reach their maximum work.

22. An apparatus as in claim 2 comprising means for delivering gas after respiratory muscles reach their maximum work.

23. An apparatus as in claim 2 comprising means for delivering the gas in multiple pulses during inspiration.

24. An apparatus as in claim 2 comprising means for adjusting the ventilation gas delivery to occur at any time within the inspiratory phase, depending on the comfort and ventilatory needs of the patient, wherein a time in the inspiratory phase is determined by information from the breath sensor.

25. An apparatus as in claim 23 wherein the adjustment means is capable of adjusting the ventilation gas delivery automatically by a physiological feedback mechanism.

26. An apparatus as in claim 24 wherein the feedback mechanism is based on airway gas concentrations.

27. An apparatus as in claim 24 wherein the feedback mechanism is based on depth of breathing.

28. An apparatus as in claim 24 wherein the feedback mechanism is based on rate of breathing.

29. An apparatus as in claim 24 wherein the feedback mechanism is based on pulse oximetry.

30. An apparatus as in claim 23 wherein the adjustment means is capable of being made manually by the user.

31. An apparatus as in claim 23 wherein the adjustment means is capable of being adjusted by a patient.

32. An apparatus as in claim 23 wherein the adjustment means is capable of being adjusted by the clinician.

33. An apparatus as in claim 2 wherein the ventilation gas delivery means is a primary ventilation gas delivery means and the apparatus further comprises means for delivering a secondary ventilation gas, the secondary gas delivery means comprising a lower gas flow rate compared to the primary ventilation gas delivery.

34. An apparatus as in claim 32 comprising means to deliver the secondary ventilation gas early in inspiration.

35. An apparatus as in claim 32 comprising means to deliver the secondary ventilation gas throughout inspiration.

36. An apparatus as in claim 32 comprising means to deliver the secondary ventilation gas during exhalation.

37. An apparatus as in claim 32 wherein the secondary ventilation gas displaces CO2 in the upper airway, such that the primary ventilation gas when delivered entrains air from the upper airway into the lower airways, wherein the entrained air is low in CO2, preferably at least 2% lower in CO2 compared to when the secondary ventilation gas is turned off.

38. An apparatus as in claim 32 wherein the secondary ventilation gas comprises a high oxygen concentration, such as 50%-100% and preferably 80%-100%, and the primary ventilation gas comprises a lower oxygen concentration, such as 21%-60%.

39. An apparatus as in claim 2 comprising means to adjust one of a pressure and a flow rate amplitude of the ventilation gas delivery.

40. An apparatus as in claim 2 comprising means to adjust the shape of the ventilation gas delivery pressure or flow rate waveform into a desired waveform, including at least one of a sine wave, an ascending wave, a descending wave or a square wave, wherein the adjusting means comprises at least one of a valve, an orifice, a piston and a regulator.

41. An apparatus as in claim 2 wherein the ventilation gas delivery comprises a primary ventilation gas delivery and the apparatus further comprises means to delivery gas into an airway during exhalation to provide a counter-resistance to exhaled flow, wherein the counter-resistance gas flow dynamics are selected to reduce airway collapse.

42. An apparatus as in claim 40 comprising means to deliver the counter-resistance gas at a selectable strategic time within the expiratory phase including one of early in exhalation or late in exhalation.

43. An apparatus as in claim 40 wherein the counter-resistance gas delivery occurs throughout exhalation.

44. An apparatus as in claim 40 comprising means to deliver the counter-resistance gas in an oscillatory pattern.

45. An apparatus as in claim 40 comprising means to deliver the counter-resistance gas in a turbulent pattern.

46. An apparatus as in claim 40 comprising means to deliver the counter-resistance gas in a laminar pattern.

47. An apparatus as in claim 40 wherein the counter-resistance gas delivery dynamics create a substantially uniform velocity profile in the airway.

48. An apparatus as in claim 40 wherein the counter-resistance gas delivery dynamics create a substantially non-uniform velocity profile in the airway.

49. An apparatus as in claim 2 comprising means, in addition to the primary ventilation gas delivery, to actively remove airway gas from the airway to reduce the CO2 content of gas in the airway.

50. An apparatus as in claim 2 wherein the ventilation gas comprises at least one of following:

oxygen, or helium-oxygen mixtures, or nitric oxide mixtures, or other therapeutic gases.

51. An apparatus as in claim 2 comprising means to deliver a medicant.

52. An apparatus as in claim 2 further comprising means to deliver one or more conjunctive therapies and (a) a secondary gas delivery;

(b) a delivery of gas during exhalation to cause exhaled flow counter-resistance;

(c) a removal of gas from the airway;

(d) delivery of a therapeutic gas such as helium-oxygen or nitric oxide;

(e) delivery of a medication.

53. An apparatus as in claim 51 further comprising means to adjust the conjunctive therapies based on the needs of the patient, wherein the adjustment means can be manual or automatic based on a feedback, and wherein the adjustment means can permit turning the conjunctive therapy on or off or varying the amplitude of the conjunctive therapy.

55. An apparatus as in claim 2 wherein the ventilation gas source comprises a liquid oxygen supply source with a gaseous oxygen output orifice of greater than 0.100″

diameter.

56. An apparatus as in claim 2 wherein the ventilation gas source comprises a liquid oxygen supply unit comprising a heater to increase the rate of oxygen gas production.

57. An apparatus as in claim 2 wherein the ventilation gas source comprises a liquid oxygen supply unit comprising a reservoir for storing oxygen converted to gaseous oxygen, wherein the reservoir stores greater than 80 ml of gaseous oxygen.

58. An apparatus as in claim 2 wherein the ventilation gas source comprises an oxygen supply unit, such as compressed oxygen gas or liquid oxygen, wherein the supply unit comprises multiple pressure regulator settings configured to regulate the gas at different gas pressures, wherein the regulator settings are adapted to be selectable by the user for regulating a pressure of a gaseous phase oxygen at different pressure levels.

59. An apparatus as in claim 2 comprising means to regulate pressure output from the gas source, an accumulator to accumulate gas at the regulated pressure, an on/off valve for controlling flow output from the accumulator to the patient and the sensor comprises breath sensors to determine the breath phase of the patient.

60. An apparatus as in claim 2 wherein the ventilation gas source comprises a compressed oxygen gas canister comprising a regulator wherein the regulator comprises a gas output orifice configured to provide an output of 10-40 psi and greater than 6 liters per minute.

61. An apparatus as in claim 2 wherein the ventilation gas source comprises an integral oxygen generator unit, a pressure amplifier, a pump to boost the pressure amplifier, and a gas reservoir.

62. An apparatus as in claim 60 wherein the pressure amplifier is pneumatic.

63. An apparatus as in claim 60 wherein the pressure amplifier is electro-pneumatic.

64. An apparatus as in claim 60 wherein the pressure amplifier amplifies pressure from ambient pressure to at least 10 psi and preferably to at least 20 psi.

65. An apparatus as in claim 60 wherein the pressure amplifier comprises two sections, a first gas input section and a second gas output section, wherein the cross-sectional area of the input section is smaller than the cross-sectional area of the output section, wherein source gas pressure is brought into the first section and expelled through the second section.

66. An apparatus as in claim 2 further comprising a gas accumulator, wherein the accumulator accumulates the volume of gas being delivered to the patient in one breath for each breath delivered.

67. An apparatus as in claim 65 wherein the accumulator is a cylinder with a stroking piston.

68. An apparatus as in claim 2 further comprising means to draw in ambient air in to a ventilation gas delivery circuit to provide the ability to deliver ventilation gas to the patient with oxygen concentrations from 21% to 100%.

69. An apparatus as in claim 67 wherein the means to draw in ambient air comprises a Venturi unit wherein the Venturi is created by ventilation gas flow dynamics in the ventilation gas delivery circuit.

70. An apparatus as in claim 67 wherein the ambient air is drawn into a gas volume accumulator, wherein the accumulator includes a stroking piston

71. An apparatus as in claim 67 wherein the ambient air is drawn in by a pump.

72. An apparatus as in claim 2 wherein the ventilator comprises an alternating cylinder design, wherein during a breath cycle of the patient, a first cylinder compresses with pressurized ventilation gas while a second cylinder decompresses pressurized ventilation gas to the patient, and wherein during a subsequent breath cycle of the patient, the first cylinder decompresses to the patient and the second cylinder re-pressurizes from the gas source.

73. An apparatus as in claim 71 wherein the cylinders include a stroking piston.

74. An apparatus as in claim 2 comprising a ventilation gas delivery circuit including:

(a) an array of accumulators;

(b) an array of gas flow orifices;

(c) accumulator outlet valves to open or close the output of the accumulators;

(d) means to select the flow orifice that the ventilation gas travels through; and

(e) means to select and open or close the accumulator outlet valves to control which accumulator outlet is open and which are closed.

75. An apparatus as in claim 73 wherein the accumulators are arranged in parallel.

76. An apparatus as in claim 73 wherein the accumulators comprise multiple volume sizes.

77. An apparatus as in claim 73 wherein the orifices comprise different orifice dimensions.

78. An apparatus as in claim 2 further comprising a gas volume accumulator comprising:

(a) a cylinder, (b) a stroking piston within the cylinder, (c) an inlet and outlet port on one side of the piston and an spring element on the opposite side of the piston, (d) a valve means to control the filling and emptying of the cylinder, wherein the spring element comprises a spring force sufficient to accelerate the emptying of the gas out of the cylinder to the patient.

79. An apparatus as in claim 2 further comprising a gas volume accumulator comprising a cylinder with an internal stroking piston, wherein a geometric volume of the cylinder is adjustable.

80. An apparatus as in claim 78 wherein the cylinder volume adjustment means is a moveable end-cap on one end of the cylinder wherein the end-cap slides axially in the inner diameter of the cylinder.

81. An apparatus as in claim 78 wherein the cylinder volume adjustment is adjusted manually, for example by rotation of a knob.

82. An apparatus as in claim 78 wherein the cylinder volume adjustment is adjusted automatically, for example by use of a motor.

83. An apparatus as in claim 78 wherein the cylinder volume adjustment is monitored by use of a position scale, such as an axial scale to determine the position of said end-cap, or a radial scale to determine the position of said knob.

84. An apparatus as in claim 78 wherein the cylinder volume adjustment is monitored by use of a position sensor, such as an axial sensor to determine the position of the end-cap, or a radial sensor to determine the position of the knob.

85. An apparatus as in claim 2 further comprising valves and control means to shape a ventilation gas delivery profile as desired, such as a sine wave, square wave or accelerating or decelerating wave.

86. An apparatus as in claim 2 further comprising a gas accumulator wherein the gas accumulator is shaped non-cylindrically.

87. An apparatus as in claim 2 further comprising a gas accumulator wherein the gas accumulator is shaped with a concave curve.

88. An apparatus as in claim 2 further comprising a gas accumulator wherein the gas accumulator comprises a bone-shaped cross section.

89. An apparatus as in claim 2 further comprising a gas accumulator wherein the gas accumulator comprises an array of separate interconnected cylinders.

90. An apparatus as in claim 2 further comprising a gas accumulator wherein the gas accumulator is comprised of tubing.

91. An apparatus as in claim 2 wherein a ventilation gas supply reservoir is configured non-cylindrically, such as but not limited to a concave shape, a bone-shaped cross section, an array of interconnected cylinders, or curved conduit.

92. An apparatus as in claim 2 wherein the catheter includes a catheter tip that is restricted to provide the desired amount of gas exit speed, typically 50 to 300 meters per second and preferably 100-250 meters per second.

93. An apparatus as in claim 91 wherein the catheter tip is restricted to produce the desired amount of entrainment of upper airway air, typically 10-200% and preferably 25-100%.

94. An apparatus as in claim 91 wherein the catheter tip restriction is constant.

95. An apparatus as in claim 91 wherein the catheter tip restriction is variable.

96. An apparatus as in claim 91 wherein the catheter tip restriction is variable wherein the restriction is varied by the use of an adjustable member in the gas flow lumen of the catheter tip.

97. An apparatus as in claim 95 wherein the adjustable member adjusts radially to decrease or increase the gas flow lumen diameter.

98. An apparatus as in claim 95 wherein the adjustable member axially slides to actuate an increase or decrease in the gas flow lumen diameter.

99. An apparatus as in claim 2 wherein the gas flow lumen is restricted to produce an exit speed of typically 50-300 meters per second and preferably 100-250 meters per second.

100. An apparatus as in claim 98 wherein the gas flow lumen tip diameter is restricted to an inner diameter of 0.5 mm to 2.0 mm, and preferably 1.0 mm to 1.6 mm.

101. An apparatus as in claim 2 comprising a main ventilation gas flow opening at the distal tip to deliver the main ventilation gas toward the lung, and comprising a secondary opening configured to direct delivery of the secondary gas upward toward the larynx.

102. An apparatus as in claim 2 comprising gas flow ports near the distal tip wherein the ports are configured to allow gas to exit the catheter multi-directionally, wherein the ports and multidirectional flow is selected to produce a uniform or semi-uniform velocity profile in the airway.

103. An apparatus as in claim 2 comprising a generally 360°

curve at its end which is inserted into the trachea, wherein the catheter gas delivery lumen is blocked to gas flow at the tip of the catheter, and comprising a gas exit port located on the curved section of the catheter at a location to direct the exiting gas flow toward the lung, and wherein the radius of the curve positions a portion of the curve against the anterior tracheal wall.

104. An apparatus as in claim 2 comprising a generally a 540°

curve at its end which is inserted into the trachea, wherein the curve positions the tip of the catheter pointing toward the lung, wherein the radius of the curve positions a portion of the curve against the anterior and posterior wall of the trachea.

105. An apparatus as in claim 2 comprising an outer cannula sleeve, wherein the outer cannula sleeve comprises a stomal sleeve, and wherein the outer cannula sleeve directs the catheter tip to the center of the trachea.

106. An apparatus as in claim 2 comprising (a) a spacer positioned inside the trachea used to space the catheter away from the stomal tissue;

(b) a curve configured to position a portion of the distal section of the catheter against the anterior tracheal will;

(c) a curve to position the tip of the catheter away from the airway wall and directed toward the lungs.

107. An apparatus as in claim 2 with a distal section that is inserted into a patient wherein the inserted section is comprised of a soft material of 20-80 Shore A durometer and preferably 30-50 Shore A durometer and further comprising a rigid member imbedded into the construction to provide the soft material semi-rigidity.

108. An apparatus as in claim 106 wherein the rigid member is a spring material.

109. An apparatus as in claim 106 wherein the rigid member is a shape memory alloy material.

110. An apparatus as in claim 106 wherein the rigid member is a malleable material.

111. An apparatus as in claim 2 wherein the catheter comprises thermally responsive material in its construction which causes a change from a first shape to a second shape of the catheter when reaching body temperature, wherein the first shape is configured to aide in insertion of the catheter and the second shape is configured to aide in atraumatic positioning of the catheter in the airway and to direct the gas exit of the catheter to the lungs.

112. A ventilation catheter as in claim 2 wherein the catheter patient end is configured to connect to a standard 15 mm connector a tracheal tube, such as a tracheostomy tube or laryngectomy tube, and comprising a sensor extension that extends into the shaft of the tracheal tube or beyond the distal tip of the tracheal tube.

113. An apparatus as in claim 2 comprising at its distal tip a radially expandable or compressible basket configured to anchor the catheter in the airway and position the tip of the catheter generally in the center of the airway.

114. An apparatus as in claim 2 comprising a outer diameter mating stomal sleeve configured for insertion into the stomal tract and for insertion of the catheter through the sleeve, wherein the sleeve further comprises a spacer on its distal end configured to position the catheter tip away from the anterior tracheal wall.

115. An apparatus as in claim 2 comprising:

(a) a distal section inserted into the trachea wherein the distal inserted section comprises a generally 90°

curve to position the tip of catheter to be pointing toward the lungs;

(b) an flange placed on the catheter shaft positioned outside the patient comprising means to axially adjust the placement of the flange on the catheter shaft and comprising means to lock the axial position of flange on the catheter shaft;

(c) length markings on the catheter shaft to correspond to the flange position.

116. An apparatus as in claim 2 comprising a compressible member for sealing with and securing to the stomal tract.

117. An apparatus as in claim 2 comprising a signal element recognizable by the ventilator, wherein the signal element defines a therapeutic attribute of the catheter, such as patient compatibility, intended disease state, or length of usage of therapy by the patient, and wherein the ventilator comprises the ability to recognize the signal element and alter its output based on the signal.

119. An apparatus as in claim 2 wherein the breath sensor comprises two sensors wherein a first sensor is a negative coefficient thermistor and a second sensor is a positive coefficient thermistor.

120. An apparatus as in claim 2 wherein the breath sensor comprises two pair of thermistors, wherein each pair is connected to a wheatstone bridge circuit, and wherein one par of thermistors are negative coefficient thermistors and the second pair of thermistors are positive coefficient thermistors.

121. An apparatus as in claim 2 wherein the breath sensor comprises at least two thermistors, wherein at least one thermistor is located on the surface of the catheter facing the larynx and at least one thermistor is located on the surface of the catheter facing the lungs.

54. An apparatus for providing ventilatory assistance to a patient wherein a gas volume is delivered into an airway of the patient via a catheter indwelling in the airway and wherein the apparatus is adapted such that:

(a) the gas volume is delivered at a rate in synchrony with the patient'"'"'s spontaneous breathing and delivered during the patient'"'"'s inspiratory phase;

(b) the gas volume delivered is 5-50% of the patient'"'"'s natural tidal volume;

(c) a driving pressure in the catheter is 5-25 psi, a peak flow rate of gas delivery is 15-35 liters per minute;

(d) a gas delivery time is 0.1 to 0.8 seconds;

(e) an exit speed of gas out of the catheter tip is 25-250 meters per second causing 10-100% volume entrainment; and

(f) the ventilator is synchronized with the patient'"'"'s breathing pattern by using a breath sensor located in the airway of the patient to measure tracheal airflow

118. A stomal sleeve comprising an external flange on a first proximal end and an internal flange on a second distal end, wherein the internal flange is fold-able and compressible into a low profile state prior to insertion, and can be unfolded and released into its expanded state after insertion into the stoma, and can further be refolded into its low profile state for removal from the stoma.

122. An apparatus comprising the dimensions of 0.5-15 cm insertion length, 20-200 cm overall length, working inner diameter of 2.0-4.0 mm, nozzle diameter at tip of catheter of 0.7-1.0 mm, and outer diameter of insertion section of 2.0-6.5 mm.

124. A method as in claim 122 wherein the ventilation gas volume delivered is 5-50% of the patient'"'"'s natural tidal volume.

125. A method as in claim 122 wherein the ventilation gas driving pressure is 5-25 psi.

126. A method as in claim 122 wherein the ventilation peak flow rate delivery is 15-35 liters per minute.

127. A method as in claim 122 wherein the ventilation gas delivery time is 0.1 to 0.8 seconds.

128. A method as in claim 122 wherein the ventilation gas exit speed out of the catheter tip is 25-250 meters per second.

129. A method as in claim 122 wherein the ventilation gas exit airflow dynamics are selected to cause 10-100% volume entrainment of gas from the upper airway into the lung with the ventilation gas.

130. A method as in claim 122 wherein the ventilation gas delivery amplitude is selected to cause a less negative pressure in the patient'"'"'s lung during inspiration compared to the negative pressure during un-assisted breathing.

131. A method as in claim 122 wherein the ventilation gas delivery amplitude is selected to cause a positive pressure in the patient'"'"'s lung during inspiration compared to the negative pressure during un-assisted breathing.

132. A method as in claim 122 wherein the breath sensor comprises two individual sensors used to obtain a comparison between the two individual sensors wherein the comparison is used to compensate for drifts and signal artifacts.

133. A method as in claim 122 wherein the individual sensor comparison is differentiated to correlate the signal to different parts of the breathing curve.

134. A method as in claim 122 wherein a liquid oxygen system is used as the ventilation gas source.

135. A method as in claim 122 wherein a compressed oxygen gas source is used as the ventilation gas source.

136. A method as in claim 122 wherein an oxygen generating system is used as the ventilation gas source.

137. A method as in claim 122 wherein a supply volume of oxygen rich gas is integrated into the ventilator.

138. A method as in claim 122 wherein the ventilation gas is delivered after the inspiratory flow rate reaches its peak amplitude.

139. A method as in claim 122 wherein the ventilation gas is delivered after the respiratory muscles reach their maximum work.

140. A method as in claim 122 wherein the ventilation gas is delivered in multiple pulses during inspiration.

141. A method as in claim 122 wherein the ventilation gas is delivery is adjustable to occur at any time within the inspiratory phase, depending on the comfort and ventilatory needs of the patient, wherein the time in the inspiratory phase is determined by information from the breath sensor.

142. A method as in claim 140 wherein the adjustment is made automatically by a physiological feedback mechanism.

143. A method as in claim 141 wherein the feedback mechanism is based on airway gas concentrations.

144. A method as in claim 141 wherein the feedback mechanism is based on depth of breathing.

145. A method as in claim 141 wherein the feedback mechanism is based on rate of breathing.

146. A method as in claim 141 wherein the feedback mechanism is based on pulse oximetry.

147. A method as in claim 140 wherein the adjustment is made manually by the user.

148. A method as in claim 140 wherein the adjustment is made by the patient.

149. A method as in claim 140 wherein the adjustment is made by the clinician.

150. A method as in claim 122 wherein in addition to the primary ventilation gas delivery, a delivery of secondary ventilation gas comprising a lower gas flow rate compared to the primary ventilation gas delivery, is delivered.

151. A method as in claim 149 wherein the secondary ventilation gas is delivered early in inspiration.

152. A method as in claim 149 wherein the secondary ventilation gas is delivered throughout inspiration.

153. A method as in claim 149 wherein the secondary ventilation gas is delivered during exhalation.

154. A method as in claim 149 wherein the secondary ventilation gas displaces CO2 in the upper airway, such that the primary ventilation gas when delivered entrains air from the upper airway into the lower airways, wherein the entrained air is low in CO2, preferably at least 2% lower in CO2 compared to when the secondary ventilation gas is turned off.

155. A method as in claim 149 wherein the secondary ventilation gas comprises a high oxygen concentration, such as 50%-100% and preferably 80%-100%, and the primary ventilation gas comprises a lower oxygen concentration, such as 21%-60%.

157. A method as in claim 122 wherein the ventilation gas delivery pressure of flow rate waveform is shaped into a desired waveform, such as a sine wave, an ascending wave, a descending wave or a square wave.

158. A method as in claim 122 wherein in addition to the primary ventilation gas delivery, gas is delivered into the airway during exhalation to provide a counter-resistance to exhaled flow, wherein the counter-resistance gas flow dynamics are selected to reduce airway collapse.

159. A method as in claim 157 wherein the counter-resistance gas delivery occurs at a strategic time within the expiratory phase, for example early in exhalation or late in exhalation.

160. A method as in claim 157 wherein the counter-resistance gas delivery occurs throughout exhalation.

161. A method as in claim 157 wherein the counter-resistance gas delivery dynamics are oscillatory.

162. A method as in claim 157 wherein the counter-resistance gas delivery dynamics are turbulent.

163. A method as in claim 157 wherein the counter-resistance gas delivery dynamics are laminar.

164. A method as in claim 157 wherein the counter-resistance gas delivery dynamics create a substantially uniform velocity profile in the airway.

165. A method as in claim 157 wherein the counter-resistance gas delivery dynamics create a substantially non-uniform velocity profile in the airway.

166. A method as in claim 122 wherein in addition to the primary ventilation gas delivery, airway gas is actively removed from the airway to reduce the CO2 content of gas in the airway.

167. A method as in claim 122 wherein the ventilation gas may comprise oxygen, or helium-oxygen mixtures, or nitric oxide mixtures.

168. A method as in claim 122 wherein a medicant is delivered to the patient during.

169. A method as in claim 122 further comprising in addition one or more of the conjunctive therapies:

(a) a secondary gas delivery;

(b) a delivery of gas during exhalation to cause exhaled flow counter-resistance;

(c) a removal of gas from the airway;

(d) delivery of a therapeutic gas such as helium-oxygen or nitric oxide;

(e) delivery of a medication.

170. A method as in claim 168 further wherein the conjunctive therapies are adjustable based on the needs of the patient, wherein the adjustment can be manual or automatic based on a feedback, and wherein the adjustment can be on or off or varying the amplitude.

123. A method for providing ventilatory assistance to a patient, comprising the steps of:

(a) delivering a gas volume into the airway via a catheter indwelling in the airway;

(b) synchronizing the delivery volume to a rate synchronized with the patient'"'"'s spontaneous breathing;

(c) delivering the delivery volume during the patient'"'"'s inspiratory phase;

(d) providing the gas volume by a wearable ventilator;

(e) synchronizing the ventilator with the patient'"'"'s breathing pattern by using a breath sensor adapted to be located in a patient'"'"'s airway to measure tracheal airflow.

171. A method for providing ventilatory assistance to a patient wherein a gas volume is delivered into the airway via a catheter indwelling in the airway and wherein:

(a) the volume is delivered at a rate in synchrony with the patient'"'"'s spontaneous breathing and delivered during the patient'"'"'s inspiratory phase;

(b) the volume delivered is 5-50% of the patient'"'"'s natural tidal volume;

(c) the driving pressure in the catheter is 5-25 psi, the peak flow rate of gas delivery 15-35 liters per minute;

(d) the gas delivery time is 0.1 to 0.8 seconds;

(e) the exit speed of gas out of the catheter tip is 25-250 meters per second causing 10-100% volume entrainment;

(f) the ventilator is synchronized with the patient'"'"'s breathing pattern by using a breath sensor located in the airway of the patient to measure tracheal airflow

172. A method for acclimating a patient to a transtracheal ventilation therapy wherein:

(a) the patient is exposed to a tolerance test using a non-invasive means such as a nasal gastric tube placed in the upper airway through the nose, (b) the patient is provided a percutaneous miniature tracheotomy procedure, (c) a temporary acclimation catheter or stomal sleeve is inserted into the stoma, (d) a therapeutic ventilation catheter is placed into the stoma, (e) ventilation therapy is started.