The respiratory conduit includes at least two air flow control devices, wherein {TAIL ~ the at least one airflow control device} is configured to withdraw air from at least one location within {HEAD ~ the respiratory conduit} 
The respiratory conduit includes at least two air flow control devices , wherein { TAIL ~ the at least one airflow control device } is configured to withdraw air from at least one location within { HEAD ~ the respiratory conduit }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD