"De-airing" in open heart surgery: report from the CVSAP nation-wide survey and literature review

Since the beginning of cardiac surgery, retained intracardiac air has been an important problem. While transesophageal echocardiography enabled to visualize the air and de-airing procedures have been routinely done, they appear to vary much among institutions not necessarily based on firm scientific evidence. Thus, "de-airing" was chosen as the theme of 2016 CVSAP (cardiovascular surgery and anesthesia and perfusion) symposium and a nation-wide questionnaire survey was carried out prior to it. This paper reports on its results and illustrate "the best of de-airing" based on literature review. The collection rate of the questionnaire survey was 77.9% (278/357) and 83.3% (85/102) from the major institutions of surgeons and anesthesiologists, respectively. More than 90% of both consider de-airing as important, since adverse events of air embolism were actually encountered including critical ones. Most routinely performed de-airing procedures are posture change, lung inflation and aspiration through the vent cannulae. Direct aspiration is performed in one-third of institutions. Carbon dioxide insufflation is performed in 82.5% of institutions (mostly 2-3 L/min). However, not a few surgeons are skeptical for its significance. While many surgeons are grateful for collaboration by anesthesiologists, some expect more information sharing between them. They also expect that clinical engineers understand "de-airing" better and operate the extracorporeal circulation system appropriately to avoid an occurrence of undesirable event. Some surgeons anticipated a convenient device for de-airing. Furthermore, some questions to be solved in the future were raised, including how meticulously the bubbles should be removed or how efficient carbon dioxide insufflation is.