Pressure controlled breathing aid

Abstract

The ventilation module ( 8 ) regulates the inspiratory pressure (P) according to an inspiratory pressure order (AI). A control module ( 9 ) compares the breathed volume at each cycle (VTI) with a minimum volume order (VRImini) and varies the pressure order (AI) in the direction tending to maintain the breathed volume (VTI) just over the minimum (VTImini), but keeping the pressure order (AI) within the interval comprised between the two extreme values (AImini, AImaxi). Utilization to combine the advantages of the pressure mode ventilation with those of the volumetric ventilation.

1 . (canceled) 
     
     
         2 . A method for controlling a breathing aid apparatus, while providing breathing aid to a patient at a target gas pressure, the method comprising:
 determining a breathed volume of the patient;   comparing the determined breathed volume with a predetermined volume threshold;   resetting the target gas pressure based at least on the determined breathed volume of the patient and a minimum pressure threshold, by increasing the target gas pressure if the determined breathed volume is lower than the predetermined volume threshold and by decreasing the target gas pressure to at most the minimum pressure threshold if the determined breathed volume is higher than the predetermined volume threshold; and   delivering the reset target gas pressure to the patient.   
     
     
         3 . A method according to  claim 2 , wherein the step of resetting the target gas pressure is further based on a maximum pressure threshold, by increasing the target gas pressure to at most the maximum pressure threshold if the determined breathed volume is lower than the predetermined volume threshold. 
     
     
         4 . A method according to  claim 2 , wherein the determined breathed volume for the patient comprises a volume inspired by the patient. 
     
     
         5 . A method according to  claim 2 , wherein the determined breathed volume for the patient comprises a volume expired by the patient. 
     
     
         6 . A method for controlling a breathing aid apparatus while providing breathing aid to a patient, the method comprising:
 delivering a first target gas pressure to a patient;   determining an actual breathed volume for the patient during the step of delivering the first target gas pressure to the patient;   setting a second target gas pressure based on both the determined breathed volume and a preset threshold volume, wherein the second target gas pressure is higher than the first target gas pressure if the actual breathed volume is lower than the preset threshold volume and the second target gas pressure is lower than the second target gas pressure if the actual breathed volume is higher than the preset threshold volume;   comparing the second target gas pressure to a minimum pressure threshold; and   delivering gas to the patient according to the second target gas pressure and the step of comparing the second target gas pressure to the minimum pressure threshold.   
     
     
         7 . A method according to  claim 6 ,
 wherein the comparing step further comprises determining that the second target gas pressure is greater than the minimum pressure threshold; and   wherein the step of delivering gas to the patient according to the second target gas pressure and the comparing step further comprises delivering the second target gas pressure to the patient.   
     
     
         8 . A method according to  claim 6 ,
 wherein the comparing step further comprises determining that the second target gas pressure is less than the minimum pressure threshold; and   wherein the step of delivering gas to the patient according to the second target gas pressure and the comparing step further comprises delivering the minimum pressure threshold to the patient.   
     
     
         9 . A method according to  claim 6 ,
 wherein the comparing step further comprises comparing the second target gas pressure to a maximum pressure threshold.   
     
     
         10 . A method according to  claim 9 ,
 wherein the comparing step further comprises determining that the second target gas pressure is less than the maximum pressure threshold; and   wherein the step of delivering gas to the patient according to the second target gas pressure and the comparing step further comprises delivering the second target gas pressure to the patient.   
     
     
         11 . A method according to  claim 9 ,
 wherein the comparing step further comprises determining that the second target gas pressure is greater than the maximum pressure threshold; and   wherein the step of delivering gas to the patient according to the second target gas pressure and the comparing step further comprises delivering the maximum pressure threshold to the patient.   
     
     
         12 . A method according to  claim 6 , wherein the actual breathed volume for the patient comprises to volume inspired by the patient. 
     
     
         13 . A method according to  claim 6 , wherein the actual breathed volume for the patient comprises a volume expired by the patient. 
     
     
         14 . A breathing aid device, comprising:
 a patient connection;   an inspiratory branch in fluid communication with said patient connection, said inspiratory branch including an inspiration valve;   an expiratory branch in fluid communication with said patient connection and said inspiratory branch, said expiratory branch including an expiration valve;   a pressure detector operatively connected to said inspiratory branch;   a source of breathable gas at an adjustable pressure in fluid communication with said inspiratory branch;   a valve controller for controlling the inspiration valve and the expiration valve during expiration and during inspiration;   a pressure controller for adjusting a pressure of the source of breathable gas based on a pressure command;   a control unit for providing the pressure command to said pressure controller; and   a measuring unit for providing a signal to the control unit indicative of a measured volume of breathable gas detected per breathing cycle to the patient connection based at least on the pressure detected by the pressure detector,   wherein the control unit compares the measured volume from the measuring unit with a preset threshold volume and adjusts the pressure command in a direction tending to bring the signal from said measuring unit toward the preset threshold volume, and   wherein the control unit maintains the pressure command above a set minimum pressure threshold.   
     
     
         15 . The breathing aid device of  claim 14 , wherein the control unit maintains the pressure command below a set maximum pressure threshold. 
     
     
         16 . The breathing aid device of  claim 14 , wherein the measured volume for the patient comprises a volume inspired by the patient. 
     
     
         17 . The breathing aid device of  claim 14 , wherein the measured volume for the patient comprises a volume expired by the patient.