218 G . S . Matte et al .: J Extra Corpor Technol 2024 , 56 , 216 – 224
Table 2 . Traditional oxygenator changeout procedure requiring temporary interruption of extracorporeal support . These steps occur after multidisciplinary discussion that determines the PaO 2 change-out threshold , the patient temperature for the procedure , and timing . The perfusion team communicates progress to the care team during the procedure .
Oxygenator change-out procedure 1 . Prepare sterile cut locations : scissors , betadine / alcohol , towels , and flush solution for connections . 2 . Primary perfusionist to decide if oxygenator-only change-out will be performed versus an oxygenator-reservoir change-out . 3 . Confirm sufficient venous reservoir volume for procedure . 4 . Come off bypass and clamp arterial and venous lines ( drain patient vs . fill up per status of native cardiopulmonary function ). 5 . Replace oxygenator (± reservoir ) with new clear-primed device using precut / clamped segments of tubing with connectors already attached . Use flush solution for connections as needed . 6 . Move sweep gas line to new oxygenator . 7 . Flow through recirculation limb and verify circuit is deaired . 8 . Perform re-establishing bypass checklist . 9 . Initiate CPB . 10 . Perform secondary checklist once back on CPB . Reestablishing bypass checklist 1 . Tubing connections correct and tight . 2 . Circuit deaired . 3 . Sweep gas on and line reconnected . 4 . Tubing clamps off boot . 5 . Extra clamp ( s ) removed from arterial line . 6 . Recirculation line and purge line clamped . 7 . Pressure dome and manifold line reconnected and opened . 8 . Communicate circuit status with surgeon .
Secondary back-on checklist 1 . Verify blood color and Terumo CDI values . 2 . Change over water lines . 3 . Reconnect temperature probe ( s ). 4 . Tie band connections . 5 . Connect WAGD line .
* WAGD = waste anesthesia gas disposal .
concern for clots in the extracorporeal circuit . We have identified six options to treat oxygenator failure when there are no concerns for system blood clots and two options when concerns for system clots are present .
Oxygenator failure without concern for system blood clots
Isolated oxygenator failure can present at any time during CPB , although most often , it is a progressive change over time that affords some notice to the team [ 5 ]. An oxygenator-only change-out was long considered the gold standard intervention as it offered a definitive replacement of the failed device . Most books and review articles mention the technique without alternatives [ 5 , 7 , 13 ]. The PRONTO technique was a novel and important development since it offered a method for definitive replacement without the need to come off of CPB . However , there have been concerns with implementing universal circuit changes , particularly post-ALF , as previously described . Clinicians have sought other options that , while not offering definitive replacement of a failed device , offer time to the clinical team . Impressively , these other techniques , which piggyback oxygenation with a secondary device inserted into one of several locations in the pump circuit , may obviate the need to replace the oxygenator during CPB .
The first of these alternative techniques may be termed an arterial piggyback . Here , the patient does not need to come off bypass as a secondary oxygenator is inserted into an arterial recirculation limb of sufficient caliber to provide adequate secondary oxygenator flow with a return to the cardiotomy venous reservoir ( CVR ). This effectively pre-oxygenates the blood before passage through the failing primary device . The disadvantages of this technique are that the recirculation limb may be insufficient to provide secondary oxygenator flow and that the arterial head must provide flow to both devices . Overall output may be limited at the upper end of potential flow for a given boot in an arterial raceway since the flow to the primary and secondary oxygenators are additive . Additionally , the maximum rated flow for the primary oxygenator , which is still in line , may limit the capacity for secondary oxygenator flow since the secondary oxygenator flow is a shunt off of the post-primary-oxygenator recirculation limb . The maximum recommended flow from the manufacturer may be linked to the efficiency of an integrated arterial line filter , so clinicians must heed caution and not exceed that limit .
There are three other piggyback oxygenation techniques , and they all source blood from the venous side of the circuit . The first requires approximately 10 s off CPB to cut a Y-connector with tubing attached to the pre-oxygenator boot line . This allows the team to connect a secondary oxygenator into the circuit with the primary arterial pump providing flow to both oxygenators . The secondary oxygenator blood flow then returns to the CVR . The second venous piggyback option also requires a brief period off CPB to cut a similar connector with