Haemolysis during cardiopulmonary bypass: how to reduce the free haemoglobin by managing the suctioned blood separately

Biphasic dose-response and effects of near-infrared photobiomodulation on erythrocytes susceptibility to oxidative stress in vitro

The effect of simultaneous application of tert-butyl hydroperoxide (tBHP) and polychromatic near-infrared (NIR) radiation on bovine blood was examined to determine whether NIR light decreases the susceptibility of red blood cells (RBCs) to oxidative stress. The study assessed various exposure methods, wavelength ranges, and optical filtering types. Continuous NIR exposure revealed a biphasic response in cell-free hemoglobin changes, with antioxidative effects observed at low fluences and detrimental effects at higher fluences. Optimal exposure duration was identified between 60 s and 15 min. Protective effects were also tested across wavelengths in the range of 750-1100 nm, with all of them reducing hemolysis, notably at 750 nm, 875 nm, and 900 nm. Comparing broadband NIR and far-red light (750 nm) showed no significant difference in hemolysis reduction. Pulse-dosed NIR irradiation allowed safe increases in radiation dose, effectively limiting hemolysis at higher doses where continuous exposure was harmful. These findings highlight NIR photobiomodulation's potential in protecting RBCs from oxidative stress and will be helpful in the effective design of novel medical therapeutic devices.

Hemolysis during open heart surgery in patients with hereditary spherocytosis - systematic review of the literature and case study

BACKGROUND

Due to the distinctive nature of cardiac surgery, patients suffering from hereditary spherocytosis (HS) are potentially at a high risk of perioperative complications resulting from hemolysis. Despite being the most prevalent cause of hereditary chronic hemolysis, the standards of surgical management are based solely on expert opinion.

OBJECTIVE

We analyze the risk of hemolysis in HS patients after cardiac surgery based on a systematic review of the literature. We also describe a case of a patient with hereditary spherocytosis who underwent aortic valve repair.

METHODS

This systematic review was registered in the PROSPERO international prospective register of systematic reviews (CRD42023417666) and included records from Embase, MEDLINE, Web of Science, and Google Scholar databases. The case study investigates a 38-year-old patient who underwent surgery for an aortic valve defect in mid-2022.

RESULTS

Of the 787 search results, 21 studies describing 23 cases of HS undergoing cardiac surgery were included in the final analysis. Hemolysis was diagnosed in five patients (one coronary artery bypass graft surgery, two aortic valve bioprosthesis, one ventricular septal defect closure, and one mitral valve plasty). None of the patients died in the perioperative period. Also, no significant clinical hemolysis was observed in our patient during the perioperative period.

CONCLUSIONS

The literature data show that hemolysis is not common in patients with HS undergoing various cardiac surgery techniques. The typical management of a patient with mild/moderate HS does not appear to increase the risk of significant clinical hemolysis. Commonly accepted beliefs about factors inducing hemolysis during cardiac surgery may not be fully justified and require further investigation.

Carboxyhemoglobin in Cardiac Surgery Patients and Its Association with Risk Factors and Biomarkers of Hemolysis

BACKGROUND

Cardiac surgery with cardiopulmonary bypass (CPB) is associated with hemolysis. Yet, there is no easily available and frequently measured marker to monitor this hemolysis. However, carboxyhemoglobin (CO-Hb), formed by the binding of carbon monoxide (a product of heme breakdown) to hemoglobin, may reflect such hemolysis. We hypothesized that CO-Hb might increase after cardiac surgery and show associations with operative risk factors and indirect markers for hemolysis.

METHODS

We conducted a retrospective descriptive cohort study of data from on-pump cardiac surgery patients. We analyzed temporal changes in CO-Hb levels and applied a generalized linear model to assess patient characteristics associated with peak CO-Hb levels. Additionally, we examined their relationship with red blood cell (RBC) transfusion and bilirubin levels.

RESULTS

We studied 38,487 CO-Hb measurements in 1735 patients. CO-Hb levels increased significantly after cardiac surgery, reaching a peak CO-Hb level 2.1 times higher than baseline (P < .001) at a median of 17 hours after the initiation of surgery. Several factors were independently associated with higher peak CO-Hb, including age (P < .001), preoperative respiratory disease (P = .001), New York Heart Association Class IV (P = .019), the number of packed RBC transfused (P < .001), and the duration of CPB (P = .002). Peak CO-Hb levels also significantly correlated with postoperative total bilirubin levels (Rho = 0.27, P < .001).

CONCLUSIONS

CO-Hb may represent a readily obtainable and frequently measured biomarker that has a moderate association with known biomarkers of and risk factors for hemolysis in on-pump cardiac surgery patients. These findings have potential clinical implications and warrant further investigation.

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.

Red-Colored Urine in the Cardiac Surgical Patient-Diagnosis, Causes, and Management

Red-colored urine occurring in the intraoperative and early postoperative periods after cardiac surgery is often a cause for concern. This observation may be a result of hematuria from pathology within the urinary tract, anticoagulant-related nephropathy, drug-induced acute interstitial nephropathy, excretion of heme pigment-containing proteins, such as myoglobin and hemoglobin, and hemolysis occurring during extracorporeal circulation. Within the kidneys, heme-containing compounds result in pigment nephropathy, which is a significant contributory factor to cardiac surgery-associated acute kidney injury. Concerted efforts to reduce red blood cell damage during cardiopulmonary bypass, together with early recognition of the at-risk patient and the institution of prompt therapeutic intervention, may improve outcomes. This review addresses the diagnosis, causes, and management of red-discolored urine occurring during and after cardiac surgery.

Low-Level Light Therapy Protects Red Blood Cells Against Oxidative Stress and Hemolysis During Extracorporeal Circulation

Aim: An activation of non-specific inflammatory response, coagulation disorder, and blood morphotic elements damage are the main side effects of the extracorporeal circulation (ECC). Red-to-near-infrared radiation (R/NIR) is thought to be capable of stabilizing red blood cell (RBC) membrane through increasing its resistance to destructive factors. We focused on the development of a method using low-level light therapy (LLLT) in the spectral range of R/NIR which could reduce blood trauma caused by the heart-lung machine during surgery. Methods: R/NIR emitter was adjusted in terms of geometry and optics to ECC circuit. The method of extracorporeal blood photobiomodulation was tested during in vivo experiments in an animal, porcine model (1 h of ECC plus 23 h of animal observation). A total of 24 sows weighing 90-100 kg were divided into two equal groups: control one and LLLT. Blood samples were taken during the experiment to determine changes in blood morphology [RBC and white blood cell (WBC) counts, hemoglobin (Hgb)], indicators of hemolysis [plasma-free hemoglobin (PFHgb), serum bilirubin concentration, serum lactate dehydrogenase (LDH) activity], and oxidative stress markers [thiobarbituric acid reactive substances (TBARS) concentration, total antioxidant capacity (TAC)]. Results: In the control group, a rapid systemic decrease in WBC count during ECC was accompanied by a significant increase in RBC membrane lipids peroxidation, while in the LLLT group the number of WBC and TBARS concentration both remained relatively constant, indicating limitation of the inflammatory process. These results were consistent with the change in the hemolysis markers like PFHgb, LDH, and serum bilirubin concentration, which were significantly reduced in LLLT group. No differences in TAC, RBC count, and Hgb concentration were detected. Conclusion: We presented the applicability of the LLLT with R/NIR radiation to blood trauma reduction during ECC.

Platelet Dysfunction in Cardiopulmonary Bypass: An Experimental Comparative Study between a Centrifugal and a New Pulsatile Pump

The aim of this investigation was to study the effect of a new pulsatile pump for extracorporeal circulation (ECC) on platelet count and platelet function with respect to a Biomedicus centrifugal pump. Thirteen pigs, 8 in the pulsatile group (PG) and 5 in the centrifugal group (CG), underwent a partial extracorporeal circulation lasting 3 h. The animals were sacrificed 3 h post-ECC. The platelet study was both quantitative (platelet count) and qualitative (platelet function analysis) by assessing the closure time (CT) with a PFA-100 system. The decrease in platelet number from basal to 3 h post ECC was only significant in CG (p = 0.009). The platelet function was impaired in both groups, but the value of CT with col/ADP increased significantly only in CG (p < 0.001). The increase of CT with col/EPI was greater in CG (p = 0.07) than in PG (p = 0.2). The results indicated that the new pulsatile pump preserves platelets quantitatively and qualitatively well compared to a Biomedicus pump.

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

This prospective randomized clinical pilot study was conducted to evaluate a recently introduced reduced volume CPB system that is coated with the biopassive Xcoating™. Twenty-two patients undergoing coronary artery bypass grafting (CABG) with cardiopulmonary bypass (CPB), either with a fully heparin-coated CPB circuit (control, n=11) or with an Xcoating™ coated condensed extra-corporeal circuit (CondECC, n=11), were included.

We examined activation of the complement system (C3bc and C4bc), activation of neutrophils (BPI), the acute phase response (interleukin (IL)-6, and acute phase proteins (LBP, AGP, and CRP)), myocardial tissue injury (troponin T), hemolysis (free hemoglobin (FHb)), and clinical outcome parameters. Preoperative risk profiles were identical for both patient groups. All patients went through the procedure without major complications and were discharged from the hospital. FHb and BPI levels at the end of pump support ( p <0.01) and at 15 min after the administration of protamine ( p <0.05) were significantly higher in the control group. In addition, FHb levels were still significantly elevated upon arrival on the cardiothoracic intensive care unit (CICU) in the control group ( p <0.05). C3bc and C4bc, acute phase proteins, IL-6, and troponin T concentrations, and clinical outcome variables were identical in both patient groups.

In conclusion, the evaluated condensed extracorporeal circuit is a flexible and multifunctional CPB sytem that offers safe procedures. Furthermore, the results indicate improved biocompatibility of this option for extracorporeal circulation.

Miniaturization in cardiopulmonary bypass

Cardiopulmonary bypass (CPB) remains the key technology for more complex cardiac operations. The perfusion equipment used nowadays has seen tremendous progress since its introduction into clinical practice 50 years ago. However, overall, CPB is still far from perfect. Major haemodilution is not only a problem for red cell-dependent gas transport, but also for the platelet and humeral factor-dependent coagulation, the protein-dependent intravascular oncotic pressure and so forth. Reduction of the priming volume through further miniaturization of CPB equipment is, therefore, the most obvious next step. A systematic approach needs to optimize all CPB components, including pumps, oxygenator/heat exchanger structures, filters, reservoirs, cardiotomy suction, tubings and cannulas. This report provides an update of already commercially available low prime perfusion devices (e.g., the CORx integrated pump-oxygenator) as well as promising prototypes like the smart suction system and the smartcanula.™

Circulating non-hematological cells during cardiopulmonary bypass: new findings in cardiac surgery procedures

BACKGROUND

Several factors have been historically advocated to explain the coagulative and inflammatory disorders following cardiopulmonary bypass (CPB). In this paper, we describe the presence of circulating non-hematological cells, introduced within the bloodstream during CPB. We defined the origin of the cells and tested their impact on coagulation.

METHODS

We collected peripheral arterial blood samples in twenty consecutive coronary artery bypass graft cases at four different surgical moments and assessed the presence and nature of circulating cells with the use of the CELLSEARCH® Test, immunocytochemistry and immunofluorescence, evaluating the expression of cytokeratin and calretinin. The effect of the circulating non-hematological cells on coagulation was tested in vitro, using the ROTEM assay.

RESULTS

A mean of 263.85 ± 57.5 (median 258.5) cells were present in the samples following the suction of blood from the surgical field while all the other samples were negative (zero cells) (p<0.00001). Immunologic tests confirmed the mesothelial origin of the cells. The ROTEM® assay of the blood samples contaminated by the mesothelial cells presented longer clotting times (53.4 ± 8.2 secs 48.3 ± 8.9 sec, p=0.05), longer clot formation times (137.1 ± 31.5 sec vs 111.9 ± 25.2 sec, p=0.009), smaller alfa angle amplitudes (66.7 ± 9.1° vs 71.1 ± 5.1°, p=0.04) and maximum clot firmness times (59.0 ± 5.4 sec vs 61.9 ±4.6 sec, p=0.004) than the controls.

CONCLUSION

The presence of circulating non-hematological cells during CPB with a mesothelial immunophenotype alters in vitro coagulation assays. This finding can help to further understand the pathophysiology of CPB.

Does contemporary oxygenator design influence haemolysis?

Based on their design, all membrane oxygenators generate a certain resistance to flow. In clinical practice, this resistance is calculated by measuring both blood flow and the pressure drop over the oxygenator. Historically, some designs, such as the Kolobow spiral coil oxygenator and the Cobe flat sheet oxygenator, had quite a high pressure drop, but were, nevertheless, considered very haemocompatible. Today, both medium and low pressure drop oxygenators are commercially available. Based on physics and the existing literature, this review aims to investigate whether pressure drop by itself can be considered an independent factor of haemolysis.

Pathophysiological aspects of cardiotomy suction usage

Cardiotomy suction is used for preservation of autologous blood during on-pump cardiac surgery at present. Controversially, the exclusion of cardiotomy suction in some types of operations (coronary artery bypass surgery) is not necessarily associated with an increased transfusion requirement. On the other hand, the use of cardiotomy suction causes an amplification of systemic inflammatory response and a resulting coagulopathy, as well as exacerbation of the microembolic load and hemolysis. This leads to a tendency towards increased blood loss, transfusion requirement and organ dysfunction. On the basis of these facts, it is appropriate to reconsider routine use of cardiotomy suction in on-pump coronary artery surgery.

LIFEBRIDGE B2T--a new portable cardiopulmonary bypass system

The LIFEBRIDGE B2T is a new portable cardiopulmonary bypass (CPB) system designed for temporary circulatory support. The LIFEBRIDGE B2T consists of a disposable patient unit with a CPB circuit, a control, and a base unit. The system weighs 20 kg. We used the LIFEBRIDGE B2T in four patients for circulatory support in beating heart coronary artery bypass graft for complete revascularization. The LIFEBRIDGE B2T was connected via femoral cannulation. Concentrations of free hemoglobin (fHb), interleukin (IL)-6, and -8 were measured. For venous blood drainage, 22-24 Fr cannulae and for arterial cannulation, 16-20 Fr cannulae were used. Average extracorporeal circulation (ECC) time was 61 +/- 18 minutes. During circulatory support, the system delivered an arterial blood flow between 3.1 and 4.1 L/min. The negative pressure at the venous drainage was between -79 and -45 mm Hg. During circulatory support, fHb concentration increased from 5.8 +/- 1.7 mg/dL to a maximum of 10.2 +/- 6.2 mg/dL. Also, IL-6 and -8 increased from 2.1 +/- 0.06 to 503.3 +/- 400.7 U/L and 5.9 +/- 0.9 to 66.5 +/- 46.8 U/L, respectively. The LIFEBRIDGE B2T is a new portable and safe circulatory support system. Connected via femoral cannulation, the system provides adequate arterial blood flow and an acceptable negative pressure at the venous cannula. The fHb concentration showed only a moderate increase during ECC.

Simultaneous use of argatroban and heparin during cardiopulmonary bypass

Heparin is the routine anticoagulant for cardiopulmonary bypass, but complications due to heparin are often reported. This study assessed argatroban as an alternative to heparin. Normothermic cardiopulmonary bypass with hemodilution was performed for 2 h in 15 dogs (mean weight, 9.8 kg) randomly assigned to 3 groups of 5 each. The controls were given heparin 200 IU x kg(-1) before cardiopulmonary bypass; group A had argatroban infused continuously at a rate of 20 microg x kg(-1) x min(-1); group H/A had half doses of both heparin (100 IU x kg(-1)) and argatroban (10 microg x kg(-1) x min(-1)). Blood samples were collected at 5 time points during the experiment. Activated clotting time, hemoglobin level, platelet counts, and serum concentrations of fibrinogen, antithrombin III, and thrombin-antithrombin III complex were measured. The platelet count was reduced significantly, and the production of thrombin-antithrombin III complex was inhibited in group H/A. Activated clotting time remained <300 sec at all time points in group A, but it was maintained at approximately 400 sec in group H/A. Fibrinogen and antithrombin III levels were reduced to half in all groups after initiation of cardiopulmonary bypass. The simultaneous use of heparin and argatroban infusion might be useful for cardiopulmonary bypass with hemodilution.

Increase in plasma free haemoglobin during cardiopulmonary bypass in heart valve surgery: assessment of renal dysfunction by RIFLE classification

Heart valve surgery carries a high risk of renal insufficiency as an independent risk factor due to prolonged cardiopulmonary bypass. Multiple causes of cardiopulmonary bypass-associated renal damage have been described, and haemoglobin-induced renal injury is presently being investigated. Forty-three patients scheduled for heart valve surgery (mostly combined) were enrolled in the prospective study. Plasma free haemoglobin (PFH) levels were evaluated by photocolorimetric measurement at the start of procedures (t(0)) and before the end of extracorporeal circulation (t(1)). A statistically significant increase in PFH levels during cardiopulmonary bypass was detected [median values (interquartile range) - t(0): 62.0 (53.4) mg/L, t(1): 320.4 (352.2) mg/L], P < 0.001. A significant regression relationship between the duration of cardiopulmonary bypass and the increased PFH was found (Spearman's correlation coefficient 0.628, P < 0.001). In some elderly patients, the tendency towards a high release of PFH during cardiopulmonary bypass was more pronounced, but the overall association between age and PFH levels was of borderline significance (P = 0.077). The correlation between PFH and post-operative serum creatinine was low and non-significant, but the latter correlated highly with the pre-operative serum creatinine values (Spearman's correlation coefficient reached values of 0.6-0.7, P < 0.001). Patients were classified according to the Risk of renal failure, Injury to the kidney, Failure of kidney function, Loss of kidney function and End-stage renal failure (RIFLE) classification for acute renal dysfunction during post-operative days 1 - 4; the influence of PFH levels at t(1) on the consequent RIFLE classification was not proven (P=0.648), but 4 patients in the Injury category had shown a higher median value of PFH (433.6 mg/L) in comparison with the others (29 patients with no acute renal dysfunction - 313.7 mg/L, 10 patients at Risk - 330.1 mg/L).

Clinical evaluation of the Admiral 1.35m2 hollow-fibre membrane oxygenator

This prospective study was designed to evaluate the fundamental clinical performance of a new, small surface area oxygenator. Data were collected from twenty patients undergoing first-time coronary artery bypass grafting using this device. This study focuses on how the reduction of surface area and prime volume affects the essential function of the oxygenator in terms of oxygenation efficiency, heat transference, membrane pressure drops, haemolysis and safety. Oxygenation efficiency was deemed to be well within acceptable margins, even at high flows, over a temperature range of 32-36 degrees C. Heat-exchanger performance was assessed by recording the heater/chiller water temperature compared to retrospective data from a current standard oxygenator. Heater/ chiller water temperatures were on average 0.3 degrees C higher with the small surface oxygenator than the standard data. The air handling of the device was excellent and extremely safe. Haemolysis, measured as plasma free haemoglobin, did not increase during bypass (p > 0.05). This new oxygenator offers a reduced surface area and priming volume while still ensuring an acceptable safety reserve and performance.

A comparison of intra-operative cell-saving strategies upon immediate post-operative outcomes after CPB-assisted cardiac procedures

Cardiotomy suction has been associated with adverse outcomes under routine conditions in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). We hypothesized that the routine use of a cell saver (CS) in place of the cardiotomy sucker would have no negative impact on transfusion rate (TR), chest tube drainage (CTD), ventilation time (VT) or intensive care unit length of stay (ICULOS) while avoiding the detrimental effects of cardiotomy suction. Retrospective data were collected from 69 patients where a cell saver was not used (NCS). Prospective data were collected from 219 patients who were followed after the implementation of an intra-operative cell saver. No significant increase in transfusion rate, chest tube drainage or ventilation time was found between the NCS group and the CS group. However, post-operative hemoglobin concentrations were significantly higher in the CS group (0.0001) and the CS group spent significantly less time in the ICU (p=0.018).

Hemodynamic and functional assessment of patients with sickle cell disease and pulmonary hypertension

RATIONALE

Although pulmonary hypertension (PH) is a common complication of sickle cell disease (SCD) associated with high mortality, there exist few data characterizing hemodynamics and cardiopulmonary function in this population.

OBJECTIVES

To characterize hemodynamics and cardiopulmonary function in patients with SCD with and without PH.

METHODS

Patients with SCD with PH (n = 26) were compared with control subjects with SCD but without PH (n = 17), matched for age, hemoglobin levels, and fetal hemoglobin levels.

MEASUREMENTS AND MAIN RESULTS

Upon catheterization, 54% of the patients with PH had pulmonary arterial hypertension, and 46% had pulmonary venous hypertension. When compared with control subjects, patients with PH exhibited lower six-minute-walk distance (435 +/- 31 vs. 320 +/- 20 m, p = 0.002) and oxygen consumption (50 +/- 3% vs. 41 +/- 2% of predicted, p = 0.02), and also had mild restrictive lung disease and more perfusion abnormalities on radionuclide lung scans. The six-minute-walk distance in this population inversely correlated with tricuspid regurgitant jet velocity (r = -0.55, p < 0.001), and mean pulmonary artery pressure (r = -0.57, p < 0.001), and directly correlated with maximal oxygen consumption (r = 0.49, p = 0.004), even after adjustment for hemoglobin, supporting an independent contribution of increasing pulmonary artery pressures to loss of exercise capacity.

CONCLUSIONS

Patients with SCD-associated PH have both pulmonary arterial and venous PH associated with severe limitations in exercise capacity, likely compounded by interstitial lung fibrosis and severe anemia. These data support the use of the six-minute-walk distance as an index of PH and cardiopulmonary function in patients with SCD.

A novel device for reducing hemolysis provoked by cardiotomy suction during open heart cardiopulmonary bypass surgery: a randomized prospective study

Since the inception of cardiopulmonary bypass (CPB), little progress has been made concerning the design of cardiotomy suction (CS). Because this is a major source of hemolysis, we decided to test a novel device (Smartsuction [SS]) specifically aimed at minimizing hemolysis during CPB in a clinical setting. Block randomization was carried out on a treated group (SS, n=28) and a control group (CTRL, n=26). Biochemical parameters were taken pre-, peri-, and post CPB and were compared between the two groups using the Student's t-test with statistical significance when P<0.05. No significant differences in patient demographics were observed between the two groups. Lactate dehydrogenase (LDH) and plasma free hemoglobin (PFH) pre-CPB were comparable for the CTRL and SS groups, respectively. LDH peri-CPB was 275+/-100 U/L versus 207+/-83 U/L for the CTRL and SS groups, respectively (P<0.05). PFH was 486+/-204 mg/L versus 351+/-176 mg/L for the CTRL and SS groups, respectively (P<0.05). LDH post CPB was 354+/-116 U/L versus 275+/-89 U/L for the CTRL and SS groups, respectively (P<0.05). PFH was 549+/-271 mg/L versus 460+/-254 mg/L for the CTRL and SS groups, respectively (P<0.05). Preoperative hematocrit (Hct) of 43+/-5% (CTRL) versus 37+/-5% (SS), and hemoglobin (Hb) of 141+/-16 g/L (CTRL) versus 122+/-17 g/L (SS) were significantly lower in the SS group. However, when normalized (N), the SS was capable of conserving Hct, Hb, and erythrocyte count perioperatively. Erythrocytes (N) were 59+/-5% (CTRL) versus 67+/-9% (SS); Hct (N) was 59+/-6% (CTRL) versus 68+/-9% (SS), and Hb (N) was 61+/-6% (CTRL) versus 70+/-10% (SS) (all P<0.05). This novel SS device evokes significantly lowered blood PFH and LDH values peri- and post CPB compared with the CTRL blood using a CS system. The SS may be a valuable alternative compared to traditional CS techniques.

Chronic sickle cell lung disease: new insights into the diagnosis, pathogenesis and treatment of pulmonary hypertension

Pulmonary hypertension is a common complication of sickle cell disease (SCD). In spite of the mild elevations in pulmonary artery pressures in these patients, the associated morbidity and mortality is high. In fact, in adult patients with SCD, pulmonary hypertension is emerging as the major independent risk factor for death. The aetiology of pulmonary hypertension is probably multifactorial, including haemolysis, impaired nitric oxide bioavailability, chronic hypoxaemia, thromboembolism, parenchymal and vascular injury because of sequestration of sickle erythrocytes, chronic liver disease and asplenia. Interestingly, pulmonary hypertension is emerging as a common, and probably, invariant sequella of lifelong haemolytic anaemia in other hereditary and acquired haemolytic diseases, such as thalassaemia, stomatocytosis and spherocytosis. There are currently limited specific data on the effects of any treatment modality for pulmonary hypertension in patients with SCD. It is likely that maximization of SCD therapy, in all patients, and treatment with selective pulmonary vasodilators and antiproliferative agents, in patients with severe disease, would be beneficial. A large trial evaluating the effects of therapy for pulmonary hypertension in the SCD population is clearly indicated.