Elimination of CO2 insufflation-induced hypercapnia in open heart surgery using an additional venous reservoir.

OBJECTIVES: Carbon dioxide (CO2) gas insufflation is used for continuous de-airing during open heart surgery. The aim was to evaluate if an additional separate venous reservoir eliminates CO2 insufflation-induced hypercapnia and keeps sweep gas flow of the oxygenator constant. METHODS: A separate reservoir was used during cardiopulmonary bypass in addition to a standard venous reservoir. The additional reservoir received drained blood and CO2 gas continuously via a suction drain (1 l/min) and handheld suction devices from the surgical wound. CO2 gas was insufflated via a gas diffuser in the open wound at 10 l/min. In a cross-over design for each patient, gas and blood were either continuously drained from the additional to the standard venous reservoir or not. CO2 pressure in arterial blood (PaCO2) was measured after adjustment of sweep gas flow as necessary and after steady state of PaCO2 was observed. Mean values for each setup (median 4 times) for each patient were analysed with Wilcoxon rank-sum test. RESULTS: Ten adult patients undergoing open aortic valve replacement were included. Median PaCO2 did not differ between setups (5.41; 5.29-5.57, interquartile range vs 5.41; 5.24-5.58, P = 0.92), whereas sweep gas flow (l/min) was lower (2.58; 2.50-3.16 vs 4.42; 4.0-5.40, P = 0.002) when CO2 gas was not drained from the additional to the standard reservoir. CONCLUSIONS: An additional venous reservoir for the evacuation of blood from the open surgical wound eliminates CO2 insufflation-induced hypercapnia in open heart surgery keeping PaCO2 and sweep gas flow constant. This prevents possible CO2-induced hyperperfusion of the brain and decreases the risk of cerebral particulate embolization during CO2 insufflation for de-airing in open heart surgery. CLINICAL TRIAL REGISTRATION: NCT04202575. IRB APPROVAL DAT AND NUMBER: 2018-07-13 and 2018/1091-31.

Will high-dose heparin affect blood loss and inflammatory response in patients undergoing cardiopulmonary bypass?

INTRODUCTION: We performed a randomized study to investigate if a high versus a standard dose of heparin dose during cardiopulmonary bypass could affect intra- and post-operative bleeding and reduce the inflammatory response. METHODS: A total of 30 patients undergoing elective coronary artery bypass grafting were randomized into high or standard dose of heparin during cardiopulmonary bypass. Blood loss was documented peri- and post-operatively, and interleukin-6, tumor necrosis factor-α, and C3 were measured in conjunction with cardiopulmonary bypass. RESULTS: Data from 29 patients were analyzed after exclusion of one patient. The mean initial bolus and total heparin doses were 43,000 ± 5,800 IU versus 35,000 ± 4,100 IU, (p < 0.001), and 58,000 ± 9,500 IU versus 45,000 ± 7,900 IU, (p < 0.001) in the intervention and the control group, respectively. The median intra-operative bleeding was 150 mL (interquartile range 100-325) in the control versus 225 mL (IQR 200-350) in the intervention group, p = 0.15. The median chest tube blood loss 12 hour post-operatively was 300 mL (interquartile range 250-385) in the control versus 450 mL (IQR 315-505) in the intervention group, p = 0.029. There was no significant difference between the control group and the intervention group during cardiopulmonary bypass for the measured inflammatory markers interleukin-6 (p = 0.98), tumor necrosis factor-α (p = 0.72), or C3 (p = 0.13). CONCLUSION: This small study showed a small increase of post-operative bleeding associated with higher heparin dosage in conjunction with cardiopulmonary bypass but did not demonstrate an effect of heparin on the inflammatory response to cardiopulmonary bypass.