Method and apparatus for insufflating a cavity in the body of a human or animal subject

Abstract

An insufflator for insufflating a body cavity includes a compressed air vessel and a flow control valve for delivering insufflating air to the cavity through a first trocar. A discharge control valve at an outlet port of a second trocar exhausts insufflating air from the cavity. A pressure sensor on the first trocar monitors cavity pressure, and a microcontroller operates the flow control valve for maintaining a predefined working pressure in the cavity. A foot operated switch is operable by a surgeon for opening and closing the discharge control valve. When the pressure in the cavity drops below the predefined working pressure, the flow control valve increases the insufflating air to the cavity, thereby increasing the insufflating air flow through the cavity for removing undesirable gases. The apparatus and insufflator may also be adapted for removing smoke, nitrogen or other undesirable gases during both cauterisation and cryogenic procedures.

1 . A method for insufflating a cavity in a human or animal subject during a procedure being carried out in the cavity, the method comprising:
 delivering an insufflating fluid into the cavity,   continuously monitoring a pressure of the insufflating fluid indicative of the pressure of the insufflating fluid in the cavity,   discharging insufflating fluid from the cavity in response to a first control signal or the monitored pressure being indicative of the pressure of the insufflating fluid in the cavity exceeding a predefined working pressure or a predefined maximum pressure greater than the predefined working pressure, and   controlling the delivery of the insufflating fluid to the cavity in response to the monitored pressure for maintaining the pressure of the insufflating fluid in the cavity at a predefined working pressure.   
     
     
         2 . A method as claimed in  claim 1  in which the discharge of insufflating fluid from the cavity is controlled by a discharge control means selectively and alternately operable in a first state to minimise discharge of insufflating fluid from the cavity, and in a second state to permit flow of the insufflating fluid from the cavity. 
     
     
         3 . A method as claimed in  claim 2  in which the discharge control means is operable from the first state to the second state in response to the first control signal or the monitored pressure being indicative of the pressure of the insufflating fluid in the cavity exceeding the predefined working pressure or the predefined maximum pressure. 
     
     
         4 . A method as claimed in  claim 3  in which the discharge control means is operable from the second state to the first state in response to a second control signal or the monitored pressure being indicative of the pressure of the insufflating fluid in the cavity falling below the predefined working pressure or a predefined minimum pressure less than the predefined working pressure. 
     
     
         5 . A method as claimed in  claim 4  in which the discharge control means is maintained in the second state when the discharge control means has been operated from the first state to the second state thereof in response to the first control signal and until the occurrence of the second signal, and delivery of the insufflating fluid to the cavity is controlled in response to the monitored pressure while the discharge control means is operating in the second state between the occurrences of the first and second control signals to temporarily increase the flow of insufflating fluid to the cavity, for in turn temporarily increasing the flow rate of the insufflating fluid through the cavity for removing an undesirable gas in the cavity. 
     
     
         6 . A method as claimed in  claim 4  in which the first control signal comprises a manually generated first signal, a signal generated in response to operation of an instrument in the cavity, a signal derived from a control system operating an instrument in the cavity indicative of operation of the instrument or commencement of operation of the instrument, or a signal from a timer having timed a first predefined time period from commencement of operation of an instrument in the cavity. 
     
     
         7 . A method as claimed in  claim 6  in which the second control signal comprises a manually generated second signal, a signal generated in response to operation of an instrument in the cavity, a signal derived from a control system operating an instrument in the cavity being indicative of operation of the instrument in the cavity ceasing, a signal from a timer having timed a second predefined time period from commencement of operation of an instrument in the cavity, or a signal from a timer having timed a third predefined time period from ceasing of operation of an instrument in the cavity. 
     
     
         8 . A method as claimed in  claim 7  in which the manually generated first signal comprises a manually generated first electrical signal or a manually generated first pneumatic signal, and the manually generated second signal comprises a manually generated second electrical signal or a manually generated second pneumatic signal. 
     
     
         9 . A method as claimed in  claim 8  in which the manually generated first electrical signal is generated by an electrical switch, and the manually generated second electrical signal is generated by the electrical switch. 
     
     
         10 . A method as claimed in  claim 1  in which delivery of insufflating fluid to the cavity is temporarily suspended in response to the monitored pressure exceeding the predefined maximum pressure, and preferably, delivery of insufflating fluid to the cavity is recommenced in response to the monitored pressure falling below the predefined working pressure or the predefined minimum pressure. 
     
     
         11 . A method as claimed in  claim 1  in which the pressure indicative of the pressure of the insufflating fluid in the cavity is monitored by a pressure monitoring means. 
     
     
         12 . A method as claimed in  claim 11  in which the pressure indicative of the pressure of the insufflating fluid in the cavity monitored by the pressure monitoring means comprises the pressure of the insufflating fluid in the cavity. 
     
     
         13 . A method as claimed in  claim 11  in which the pressure indicative of the pressure of the insufflating fluid in the cavity is monitored by the pressure monitoring means without interrupting delivery of the insufflating fluid to the cavity. 
     
     
         14 . A method as claimed in  claim 11  in which the pressure monitoring means comprises a pressure sensor. 
     
     
         15 . A method as claimed in  claim 11  in which the pressure monitoring means comprises a piezoelectric pressure sensor. 
     
     
         16 . A method as claimed in  claim 11  in which the pressure monitoring means is located in or adjacent the cavity. 
     
     
         17 . A method as claimed in  claim 1  in which the discharge control means comprises a discharge control valve or a vacuum pump. 
     
     
         18 . A method as claimed in  claim 1  in which delivery of the insufflating fluid to the cavity is controlled through a flow control means. 
     
     
         19 . A method as claimed in  claim 18  in which the flow control means comprises a variable state valve. 
     
     
         20 . A method for insufflating a cavity of a human or animal subject during a procedure being carried out therein, the method comprising delivering an insufflating fluid to the cavity, monitoring a pressure of the insufflating fluid indicative of the pressure of the insufflating fluid in the cavity, discharging insufflating fluid from the cavity in response to a first control signal or the pressure in the cavity exceeding a predefined maximum pressure, and terminating discharge of the insufflating fluid from the cavity in response to a second control signal or the pressure of the insufflating fluid in the cavity falling to or just below the predefined working pressure. 
     
     
         21 . A method as claimed in  claim 20  in which the first control signal comprises a manually generated first signal, and the second control signal comprises a manually generated second signal. 
     
     
         22 . A method as claimed in  claim 21  in which the manually generated first signal comprises a manually generated first electrical signal or a manually generated first pneumatic signal, and the manually generated second signal comprises a manually generated second electrical signal or a manually generated second pneumatic signal. 
     
     
         23 . Apparatus for insufflating a cavity in the body of a human or animal subject, the apparatus comprising:
 a delivery means for delivering an insufflating fluid to the cavity,   a pressure monitoring means for monitoring a pressure of the insufflating fluid indicative of the pressure of the insufflating fluid in the cavity,   a flow control means responsive to the pressure monitoring means for controlling the flow rate of the insufflating fluid to the cavity in response to the pressure monitoring means to maintain the pressure of the insufflating fluid in the cavity at a substantially constant predefined working pressure, and   a discharge control means for controlling the flow of insufflating fluid from the cavity, the discharge control means being responsive to a first control signal for increasing discharge of insufflating fluid from the cavity, and   the flow control means is responsive to the monitored pressure in the cavity to maintain the pressure of the insufflating fluid in the cavity substantially constant at the predefined working pressure while the discharge control means is operating to increase the rate at which the insufflating fluid is being discharged from the cavity by increasing the flow rate of insufflating fluid to the cavity, for in turn increasing the flow rate of the insufflating fluid through the cavity for removing an undesirable gas from the cavity.