Objective

Cardiopulmonary bypass (CPB) has revolutionized cardiac surgery since its introduction to clinical practice in the mid-1900s. Despite the undisputed clinical benefits of CPB, the potential detrimental perioperative risks such as hemodilution, gaseous and fat microemboli (GME), and homologous RBC transfusions, must not be underestimated.
The evidence-based literature shows the positive correlation between introduced risks and adverse patient outcomes - such as neurological disorders and acute renal failure - which often result in longer ICU and hospital length of stay and/or higher mortality rates. Another critical factor in patient outcomes is the perfusionist, whose role has significantly expanded. In addition to operating the heart lung machine (HLM), perfusionists must monitor and interpret vital patient parameters from multiple devices in complex clinical situations during extracorporeal circulation.

Method

Having specific solutions and strategies in place helps clinicians ensure that cardiopulmonary bypass (CPB) is as effective and controlled as possible. One of these strategies is to establish Goal-Directed Perfusion guidelines that guarantee oxygen delivery to the patient remains above critical threshold levels. In the literature, maintaining oxygen delivery above critical values has been associated with a reduction of post-operative Acute Kidney Injury (AKI) occurrence and with a shortening of hospital and ICU length of stay (LOS). Recently released guidelines from The American Society of Extracorporeal Technology (ASET) include oxygen delivery as one of the most important considerations when setting pump flow rates.

Results

The innovative LivaNova GDP™ Monitor - a new, optional module of LivaNova CONNECT™ electronic perfusion data management system - enables intuitive monitoring and recording of all Goal-Directed Perfusion parameters. Continuous, real-time data recording and trends visualization of oxygen delivery and several other critical patient metabolic parameters are monitored, including oxygen consumption, carbon dioxide production and the oxygen delivery to carbon-dioxide production key ratio. The detailed documentation and management of these parameters helps match the adequacy of perfusion to a patient’s metabolic needs during CPB. According to Goal-Directed Perfusion principles, the perfusionist has two options for maintaining adequate oxygen levels: managing arterial flow or hematocrit values. More specifically, this involves either increasing the pump flow to compensate for a low hematocrit or limiting hemodilution to raise the hematocrit.

Conclusion

The LivaNova INSPIRE™ oxygenation system, which minimizes hemodilution, also helps implement Goal-Directed Perfusion by allowing the perfusionist to maintain a higher hematocrit during CPB to keep the patient above critical oxygen delivery thresholds. In a recent study published by Ranucci M., et al., routine use of Goal-Directed Perfusion led to a significant reduction of AKI incidence, which was further reduced by the adoption of new “ultra-low priming volume oxygenators” such as the INSPIRE 6.2 In a second study, the same research group concluded: ‘’The INSPIRE 6 oxygenator allows a significant containment of hemodilution during CPB, reducing the risk of RBC transfusions and postoperative AKI.