Evaluation of a new condensed extra-corporeal circuit for cardiac surgery: a prospective randomized clinical pilot study

Hemolysis and cardiopulmonary bypass: meta-analysis and systematic review of contributing factors

BACKGROUND

The use of cardiopulmonary bypass (CPB) is almost inevitable in cardiac surgery. However, it can cause complications, including hemolysis. Until now, there have not been any standards for reducing hemolysis from CPB. Therefore, this systematic review was conducted to determine the factors that increase or reduce hemolysis in the use of CPB.

METHODS

Keywords Earches (cardiac surgery AND cardiopulmonary bypass AND hemolysis) were done on PubMed databases and Cochrane CENTRAL from 1990-2021 for published randomized controlled trials (RCTs) that studied interventions on CPB, in cardiac surgery patients, and measured hemolysis as one of the outcomes. Studies involving patients with preoperative hematological disorders, prosthetic valves, preoperative use of intra-aortic balloon pumps and extracorporeal circulation, emergency and minimally invasive surgery are excluded RESULTS: The search yielded 64 studies that met the inclusion criteria, which involved a total of 3,434 patients. The most common surgery was coronary revascularization (75%). Out of 64 studies, 33 divided into 7 analyses. Remaining 31 studies were synthesized qualitatively. Significant decreases were found in centrifugal vs roller pumps for PFHb (p = 0.0006) and Hp (p < 0.0001) outcomes, separated vs combined suctioned blood (p = 0.003), CPB alternatives vs conventional CPB (p < 0.0001), and mini extracorporeal circulation (MiniECC) vs conventional CPB for LDH (p = 0.0008). Significant increases were found in pulsatility (p = 0.03) and vacuum-assisted venous drainage (VAVD) vs gravity-assisted venous drainage (GAVD) (p = 0.002).

CONCLUSION

The review shows that hemolysis could be caused by several factors and efforts have been made to reduce it, combining significant efforts could be beneficial. However, this review has limitations, such as heterogeneity due to no standards available for conducting CPB. Therefore, further research with standardized guidelines for CPB is needed to yield more comparable studies. Meta-analyses with more specific parameters should be done to minimize heterogeneity.

The cardioprotective and anti-inflammatory effect of inhaled nitric oxide during Fontan surgery in patients with single ventricle congenital heart defects: a prospective randomized study

Background

Fontan surgery with cardiopulmonary bypass (CPB) causes tremendous systemic stress and inflammatory responses, affecting postoperative organ function, morbidity, and mortality. Although this reaction triggers partially protective anti-inflammatory responses, it is harmful in patients with single ventricle congenital heart defects. Despite decades of research, an effective anti-inflammatory and stress defense strategy is lacking. This study investigated the influence of inhaled nitric oxide (NO) during CPB on early clinical results, including the duration of postoperative respiratory support as a primary outcome and a panel of laboratory analytes.

Methods

In this study, 115 patients were randomized to the Fontan-NO group (n = 48) and the Fontan group (n = 49). Eighteen patients were excluded from the study. The Fontan-NO group received NO inhaled directly into the oxygenator during CPB. Clinical data were collected, and blood samples were drawn for analysis at repeated intervals. Multiplex assays were used to analyze a proteome profile of molecules involved in stress response, inflammation, metabolic reactions, as well as heart and lung protection.

Results

Fontan-NO patients had significantly shorter respiratory support time with a median of 9.3 h (7.0; 13,2) vs 13.9 h (3.7; 18.5) by the absolute difference of 4.6 h [95% confidence interval, − 30.9 to 12.3; (p = 0.03)]. In addition, they have a shorter time in intensive care (p = 0.04) and lower pulmonary artery pressure after CPB discontinuation (p = 0.04), 4 h (p = 0.03) and 8 h (p = 0.03) after surgery. Fontan-NO patients also had a lower concentration of lactates (p = 0.04) and glucose after separation from CPB (p = 0.02) and lower catecholamine index (p = 0.042). Plasma factors analysis has shown a significantly higher concentration of interleukin-10, and a lower concentration of interleukin-6, interleukin-8, interleukin-1β, pentraxin, matrix metalloproteinase-8, troponin-I, creatine kinase myocardial band (CK-MB), and insulin in Fontan-NO group.

Conclusions

NO inhaled into the oxygenator during CPB can improve short-term clinical outcomes. It shortens intubation time and intensive care time. It reduces inflammatory response, improves myocardial and lung protection, and diminishes metabolic stress in patients with a single ventricle undergoing Fontan surgery.

Trial registration number: The trial was preregistered, supervised, and supported by The Polish National Science Center (NCN/01/B/NZ5/04246).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-022-00639-y.

Clinical and Biomaterial Evaluation of a new Condensed Dual-Function Extracorporeal Circuit in Reoperation for Coronary Artery Bypass Surgery

Purpose

This prospective, randomized study compared the clinical performance of three types of circuits: a newly introduced, fully-coated, interchangeable open-closed circuit with a dual configuration (hard shell with a bypass shunt), reduced length, and reduced prime of less than 800 cc (CondECC); a completely coated circuit (ECC); and a similar uncoated, open circuit with standard length and prime (CONT).

Methods

75 patients undergoing reoperation for coronary revascularization were randomly allocated into three groups (N=25): Group 1: CondECC with shortened tubing, components and an open-closed configuration of low priming volume with a centrifugal pump and a shunt which bypassed the reservoir for closed configuration; Group 2: ECC with a roller pump and hard-shell reservoir; Group 3: CONT. Blood samples for CBC, inflammatory mediators [Interleukin-2 (IL-2), Complement-3a (C3a)] and flow cytometry (CD11 b/CD18) were collected after induction (T1) and heparin administration (T2), 15 min after cardiopulmonary bypass (CPB) (T3), before cessation of CPB (T4), 15 min after reversal (T5), and the first postoperative day (T6).

Results

Leukocyte counts demonstrated significant increases at T4, T5 in CONT but remained stable in ECC and CondECC (p<0.05). Platelets were preserved better at T4, T5 in both ECC and CondECC study groups (p<0.05). IL-2 and C3a levels were significantly lower at T3, T4, T5 in CondECC and T4, T5 in ECC (p<0.05). Blood protein adsorption analysis demonstrated increased amount of microalbumin on CONT fibers (p<0.05).

Conclusions

The CondECC is a flexible, dual-function, open/closed configuration system that was easy to use, safe and achieved better biocompatibility when compared to coated and uncoated conventional circuits.

Versatile minimized system--a step towards safe perfusion

A growing body of evidence indicates the superiority of minimized cardiopulmonary bypass (CPB) systems compared to conventional systems in terms of inflammatory reactions and transfusion requirements. Evident benefits of minimized CPB systems, however, do not come without consequences. Kinetic-assisted drainage, as used in these circuits, can result in severe fluctuations of venous line pressures and, consequently, fluctuation of the blood flow delivered to the patient. Furthermore, subatmospheric venous line pressures can cause gaseous microemboli. Another limitation is the absence of cardiotomy suction, which can lead to excessive blood loss via a cell saver. The most serious limitation of minimized circuits is that these circuits are very constrained in the case of complications or changing of the surgery plan. We developed a versatile minimized system (VMS) with a priming volume of about 600 ml. A compliance chamber in the venous line decreases peaks of pressure fluctuations. This chamber also acts as a bubble trap. Additionally, the open venous reservoir is connected parallel to the venous line and excluded from the circulation during an uncomplicated CPB. This reservoir can be included in the circulation via a roller pump and be used as a cardiotomy reservoir. The amount and rate of returned blood in the circulation is regulated by a movable level detector. Further, the circuit can easily be converted to an open system with vacuum-assisted venous drainage in the case of unexpected complications. The VMS combines the benefits of minimized circuits with the versatility and safety of a conventional CPB system. Perfusionists familiar with this system can secure an adequate and timely response at expected and unexpected intraoperative complications.

Hemolysis results in impaired intestinal microcirculation and intestinal epithelial cell injury

AIM: To study the effect of circulating cell-free oxyhemoglobin (FHb) on intestinal microcirculation and intestinal epithelial injury in a rat model.

METHODS: To induce elevated intravascular circulating FHb, male Sprague-Dawley rats received water or FHb infusion. Microcirculatory changes in jejunum, ileum and colon were evaluated using fluorescent microspheres. Intestinal injury was quantified as plasmatic release of ileal lipid binding protein (iLBP) and verified by histological analysis of the ileum.

RESULTS: Water and FHb infusions resulted, when compared with saline infusion, in reduced intestinal microcirculation (after 30 min P < 0.05, or better; after 60 min FHb infusion P < 0.05 for jejunum and colon). Circulating FHb levels correlated significantly with release of iLBP (Spearman r = 0.72, P = 0.0011). Epithelial cell injury of the villi was histologically observed after water and FHb infusions.

CONCLUSION: This study shows that circulating FHb leads to a reduction in intestinal microcirculatory blood flow with marked injury to intestinal epithelial cells. These data support the hypothesis that circulating FHb contributes to the development of intestinal injury.

Clinical evaluation of minimized extracorporeal circulation in high-risk coronary revascularization: impact on air handling, inflammation, hemodilution and myocardial function

Objective: We examined intraoperative microembolic signals (GME), inflammatory response, hemolysis, perioperative regional cerebral oxygen saturation (rSO2), myocardial protection and desorbed protein amount on oxygenator fibers in high-risk patients undergoing coronary revascularization (CABG) with minimized and conventional cardiopulmonary bypass (CPB). Methods: Over a ten-month period, 40 Euroscore 6+ patients undergoing CABG were prospectively randomized to one of the two perfusion protocols (N=20): Group 1: minimized extracorporeal circuits (Mini-CPB) (ROCsafe MPC, Terumo, Ann Arbor, MI, USA) and Group 2: conventional extracorporeal circuits (CECC) (Capiox SX18, Terumo, USA). Serum creatinine kinase-MB (CKMB), free hemoglobin, interleukin-6 (IL-6) and C3a levels were measured. Blood samples were collected at T1: following induction of anesthesia; T2: thromboelastography control; T3:15 min after commencement of CPB; T4: before cessation of CPB; T5: 15 min after protamine reversal and T6: ICU. Results: Serum IL-6 levels were significantly lower in the Mini-CPB group at T4 and T5 and C3a levels were significantly less in the Mini-CPB group at T3, T4 and T5 vs. CECC (p<0.01). CKMB levels in coronary sinus blood demonstrated well preserved myocardium in the Mini-CPB group. Percentage expression of neutrophil CD11b/CD18 levels were significantly lower in the Mini-CPB group at T4 and T5 (p<0.05). There were no significant differences in air handling characteristics or free plasma hemoglobin levels in either circuit. rSO2 measurements were significantly better at T3 and T4 in the Mini-CPB vs. CECC (p<0.05) and always higher in the Mini-CPB during follow-up. Blood protein adsorption analysis of oxygenator membranes demonstrated a significantly increased amount of microalbumin on CECC fibers (p<0.05). Conclusion: Mini-CPB provided a comfort and safety level similar to conventional control via satisfactory air handling, attenuated inflammatory response and hemodilution, with a better clinical outcome in patients undergoing high-risk CABG.