Introduction

The present review aims to analyze and synthesize the growing scientific evidence supporting the benefits of implementing carbon dioxide (CO2) diffusers in the field of cardiac surgery. Clinical studies, meta-analyses and research papers related to effective deaeration, microemboli reduction and prevention of postoperative infections are examined. The review highlights the advances in diffuser technologies and their specific application in cardiac procedures, shedding light on the overall improvement of patient safety and clinical outcomes.

Cardiac surgery, especially in the context of minimally invasive procedures, presents unique challenges in terms of effective de- airing and prevention of postoperative complications. In this regard, CO2 insufflation via diffusers has become an emerging approach to address these challenges.

Effective Deaeration

The deaeration is essential during cardiac surgery to minimize the presence of air in the chest cavity. The study by Nyman et at. (2019) revealed that the use of a mini-diffuser designed specifically for minimally invasive procedures resulted in more effective deaeration compared to with devices conventional.
The  capacity  of  the  diffuser to maintain low levels of residual air even at moderate CO2 flow rates was outstanding, showing an air content of less than 1% at 15 mm depth. (1)

Illustration 1: Cardia Innovation mini-diffuser.

Microembolus Reduction

The presence of microemboli during cardiac surgery has been associated with postoperative neuropsychological disturbances. A prospective study by Nyman (2020) at the Karolinska Institute showed that CO2 insufflation using diffusers significantly reduced the number of microemboli compared to standard procedures. This reduction was not only quantitative, but also positively affected the behavior of the microemboli, suggesting potential long-term neuropsychological benefits. (2,3)

Postoperative Infection Prevention

Air contamination in the operating room can contribute to postoperative infections, particularly in cardiac surgery. Research by Persson et al. (2004) compared the air contamination rate between gas diffusers and open-end tubes. The results indicated that the use of gas diffusers, especially with CO2, significantly reduced air contamination compared to conventional methods, suggesting a positive impact on the prevention of cardiothoracic wound infections. (4)

On the other hand, the delivery technique of CO2 scrubbing is crucial, since ineffective delivery can result in the accumulation of up to 50% of air remaining within the thoracic cavity (5). Inefficient deaeration may lead to conclusions that underestimate the potential benefits of CO2 lavage. Concerns associated with CO2 lavage have been noted, such as hypercapnic acidosis leading to increased cerebral blood flow and its inherent risk of cerebral embolism, damage to red blood cells, and increased risk of thrombus formation in stagnant blood (6, 7, 8).

Based on the results of the in vitro study conducted Karin et at. (2016), it was concluded that acidosis may lead to a decrease in heparin potency. Acidosis, induced by CO2 insufflation, may predispose patients to accidental thrombus formation in stagnant blood in the open chest and cardiotome. Hypothermia applied in these procedures could further increase this risk (8).

Advantages and disadvantages of using a CO2 diffuser

AppearanceAdvantagesDisadvantages
Improved VisibilityEfficient distension of cardiac cavities, providing a clear and detailed view during surgery.
Facilitates the execution of precise procedures.
Possibility of excessive inflation, which may compromise cardiac function.
Gas Embolism Risk ReductionCO2 is more soluble in blood, minimizing the risk of gas embolism. – Less possibility of visual obstructions related to gas bubblesIt requires constant monitoring to avoid excessive CO2 accumulation.
Accurate Control with Arterial GasometryAllows for dynamicadjustments during surgery to maintain adequate CO2 levels (Perfusionists).
Contributes to avoid complications related to gaseous imbalances in the blood.
Rapid Absorption and Postoperative RecoveryCO2 is rapidly absorbed, contributing to a more comfortable recovery for the patient. – Less postoperative discomfort compared to other gases.Possibility of residual irritation due to rapid absorption of CO2.
Less Effects Adverse Secondary EffectsMinimizes side effects associated with insufflation of other gases. – Contributes to a more favorable overall patient experience.It requires careful adjustment of the technique to avoid complications.
Security in Cardiac SurgeriesContributes to a safe surgical environment by reducing the risk of air embolism and improving visibility.Inappropriate or excessive use may pose risks to the patient.
Table created by the author

Conclusions and Recommendations

Accumulating evidence from clinical studies, meta-analyses and research papers consistently supports the use of CO2 diffusers in cardiac surgery. These devices not only improve deaeration during minimally invasive procedures, but also reduce the presence of microemboli and decrease air contamination, contributing to the prevention of postoperative infections. The complications derived from their use are not statistically significant and are mainly linked to their correct use, so adequate training could reduce the risk.

Arguably, the continued implementation of these technological advances in clinical settings, supported by future research exploring additional applications and specific optimizations to further improve safety and outcomes in cardiac surgery. The adoption of CO2 diffusers emerges as a promising practice in the evolution of modern cardiac surgery.

References:

  1. Nyman J, Svenarud P, van der Linden J. Carbon dioxide de-airing in minimal invasive cardiac surgery, a new effective device. J Cardiothorac Surg [Internet]. 2019 [cited 2024 Jan 23];14(1). Available from: http://dx.doi.org/10.1186/s13019-018-0824-4
  2. Measures to Prevent Microembolization in Cardiac Surgery and during Angiography with Special Reference to Carbon Dioxide Nyman, Jesper. Jesper Karolinska Institutet. 2020;
  3. Benedetto U, Caputo M, Guida G, Bucciarelli-Ducci C, Thai J, Bryan A, et al. Carbon dioxide insufflation during cardiac surgery: A meta-analysis of randomized controlled trials. Semin Thorac Cardiovasc Surg [Internet]. 2017;29(3):301–10. Available from: http://dx.doi.org/10.1053/j.semtcvs.2017.05.002
  4. Persson M, van der Linden J. Wound ventilation with carbon dioxide: a simple method to prevent direct airborne contamination during cardiac surgery? J Hosp Infect[Internet].2004;56(2):131–6.Available from: https://www.sciencedirect.com/science/article/pii/S0195670103004195
  5. Svenarud P, Persson M, van der Linden J. Effect of CO2 insufflation on the number and behavior of air microemboli in open-heart surgery: a randomized clinical trial. Circulation 2004;109:1127–32.
  6. Landenhed M, Al-Rashidi F, Blomquist S, Hoglund P, Pierre L, Koul B. Systemic effects of carbon dioxide insufflation technique for de-airing in left-sided cardiac surgery. J Thorac Cardiovasc Surg 2014;147:295–300.
  7. Cook DJ, Plochl W, Orszulak TA. Effect of temperature and PaCO2 on cerebral embolization during cardiopulmonary bypass in swine. Ann Thorac Surg 2000;69:415–20.
  8. Gorter KA, Stehouwer MC, Van Putte BP, Vlot EA, Urbanus RT. Acidosis induced by carbon dioxide insufflation decreases heparin potency: a risk factor for thrombus formation. Perfusion 2017;32:214–9.