Pulsatile Cardiopulmonary Bypass Research Articles

Endothelial hyperpermeability after cardiac surgery with cardiopulmonary bypass as assessed using an in vitro bioassay for endothelial barrier function

BackgroundThe mechanisms causing increased endothelial permeability after cardiopulmonary bypass (CPB) have not been elucidated. Using a bioassay for endothelial barrier function, we investigated whether endothelial hyperpermeability is associated with alterations in plasma endothelial activation and adhesion markers and can be attenuated by the use of pulsatile flow during CPB. MethodsPatients undergoing cardiac surgery were randomized to non-pulsatile (n+20) or pulsatile flow CPB (n+20). Plasma samples were obtained before (pre-CPB) and after CPB (post-CPB), and upon intensive care unit (ICU) arrival. Changes in plasma endothelial activation and adhesion markers were determined by enzyme-linked immunosorbent assay. Using electric cell–substrate impedance sensing of human umbilical vein endothelial monolayers, the effects of plasma exposure on endothelial barrier function were assessed and expressed as resistance. ResultsCardiopulmonary bypass was associated with increased P-selectin, vascular cell adhesion molecule-1, and von Willebrand factor plasma concentrations and an increase in the angiopoietin-2 to angiopoietin-1 ratio, irrespective of the flow profile. Plasma samples obtained after CPB induced loss of endothelial resistance of 21 and 23% in non-pulsatile and pulsatile flow groups, respectively. The negative effect on endothelial cell barrier function was still present with exposure to plasma obtained upon ICU admission. The reduction in endothelial resistance after exposure to post-CPB plasma could not be explained by CPB-induced haemodilution. ConclusionThe change in the plasma fingerprint during CPB is associated with impairment of in vitro endothelial barrier function, which occurs irrespective of the application of a protective pulsatile flow profile during CPB. Clinical trial registrationNTR2940.

Impact of Intraoperative Events on Cerebral Tissue Oximetry in Patients Undergoing Cardiopulmonary Bypass

Previous studies showed that decreased cerebral saturation during cardiac surgery is related to adverse postoperative outcome. Therefore, we investigated the influence of intraoperative events on cerebral tissue saturation in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). A total of 52 adult patients who underwent cardiac surgery using pulsatile CPB were included in this prospective explorative study. Cerebral tissue oxygen saturation (SctO2) was measured in both the left and right cerebral hemisphere. Intraoperative events, involving interventions performed by anesthesiologist, surgeon, and clinical perfusionist, were documented. Simultaneously, in-line hemodynamic parameters (partial oxygen pressure, partial carbon dioxide pressure, hematocrit, arterial blood pressure, and CPB flow rates) were recorded. Cerebral tissue saturation was affected by anesthetic induction (p < .001), placement of the sternal retractor (p < .001), and initiation (p < .001) as well as termination of CPB (p < .001). Placement (p < .001) and removal of the aortic cross-clamp (p = .026 for left hemisphere, p = .048 for right hemisphere) led to changes in cerebral tissue saturation. In addition, when placing the aortic cross-clamp, hematocrit (p < .001) as well as arterial (p = .007) and venous (p < .001) partial oxygen pressures changed. Cerebral tissue oximetry effectively identifies changes related to surgical events or vulnerable periods during cardiac surgery. Future studies are needed to identify methods of mitigating periods of reduced cerebral saturation.

Protective Effects of Pulsatile Flow During Cardiopulmonary Bypass

Children with congenital heart disease are often operated at a very young age. Cardiopulmonary bypass (CPB) has become indispensable for these sometimes very complex operations, but one cannot neglect a possible negative impact of CPB on organ function. Traditionally, CPB was developed with non-pulsatile flow but there are clinical observations that pulsatile flow might be superior with improved patient outcomes. Therefore, we attempted to elucidate whether CPB with pulsatile flow preserves organ integrity compared with nonpulsatile flow. We studied 27 piglets of 4 weeks age and divided them into 3 experimental groups: control group (no CPB); non-pulsatile and pulsatile-CBP with 90-minutes CPB and 120-minutes recovery and reperfusion. Thereafter, histology of kidney, liver, and hippocampus was performed. Moreover, we measured adenosine triphosphate (ATP) content in these organs. Histologic evaluation revealed that laminar flow produced significant cellular edema in the kidney and hippocampus. Additionally, markers for hypoxia, apoptosis, and nitrosative stress were elevated but predominately in the hippocampus and proximal tubules of the kidney. Most of these alterations were reduced to or near control levels with pulsatile CPB. Moreover, ATP content of all 3 organs examined was higher and kidney and liver enzymes were lower in the pulsatile group compared with the non-pulsatile CPB. With regard to histologic changes, the liver seemed to be a less sensitive organ. In our study during pulsatile CPB, organ damage was significantly attenuated as compared with non-pulsatile CPB. Therefore, in pediatric patients pulsatile CPB may improve clinical outcomes.

The effect of pulsatile cardiopulmonary bypass on lung function in elderly patients.

Cardiopulmonary bypass is still a major cause of lung injury and delay in pulmonary recovery after cardiac surgery. Although it has been shown that pulsatile flow induced by intra-aortic balloon pumping is beneficial for preserving lung function, it is not clear if the same beneficial effect can be accomplished with pulsatile flow generated in the extracorporeal circuit. Therefore, we investigated the effect of pulsatile flow, produced by a centrifugal pump, on lung function in elderly patients. Serial measurements of lung biomarkers Clara cell 16 kD protein, surfactant protein D, and elastase were performed on blood samples from 37 elderly patients (≥75 years) who underwent elective aortic valve replacement surgery with CPB, either with pulsatile perfusion or continuous perfusion. Pulmonary function was assessed by postoperative ventilation time, the arterial blood oxygenation (PaO2/FiO2), the alveolar-arterial oxygen gradient (Aa-O2 gradient) and the pulmonary vascular resistance indexed by body surface area (PVRi). There was no difference in lung function between both groups, as assessed by the postoperative ventilation time, the PaO2/FiO2 ratio, and the Aa-O2 gradient. The PVRi, however, was significantly lower in the pulsatile perfusion group 15 mins after the administration of protamine (p<0.05). The plasma concentrations of the lung biomarkers increased during surgery and peaked at 1 h ICU, there were however no differences between groups. Pulsatile flow does not seem beneficial to postoperative lung function in elderly patients. Moreover, pulsatile flow does not affect lung function on a subclinical level as assessed by lung biomarkers.

Pulsatile cardiopulmonary bypass and renal function in elderly patients undergoing aortic valve surgery†.

To evaluate if pulsatile cardiopulmonary bypass (CPB) has any protective influence on renal function in elderly patients undergoing aortic valve replacement (AVR). Forty-six patients (≥ 75 years old) with aortic valve stenosis underwent AVR with either pulsatile perfusion (PP) or non-pulsatile perfusion (NP) during CPB. Haemodynamic efficacy of the blood pump during either type of perfusion was described in terms of the energy equivalent pressure and the surplus haemodynamic energy. Urine samples were collected before surgery, at sternum closure, and at 2 and 18 h of intensive care unit stay to detect acute kidney injury markers. Perioperative urine levels of N-acetyl-β-D-glucosaminidase (NAG), kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin (NGAL) were assessed together with plasma creatinine, creatinine clearance (CCr) and 24-h haemodynamic monitoring. Normally distributed continuous variables were described as mean ± standard deviation and non-normally distributed data were presented as the median [25th-75th percentiles]. PP was characterized by a significantly higher amount of surplus haemodynamic energy transferred to the patients (P < 0.001), with lower mean systemic vascular resistance during CPB (P = 0.020) and during 18 h postoperatively (group-P = 0.018). No difference was found between pre- and postoperative CCr in the PP group (71 ± 23 vs 60 ± 35 ml/min, P = 0.27), while its statistically significant perioperative decrement was observed in the NP group (67 ± 24 vs 45 ± 15 ml/min, P < 0.001). The PP group showed significantly lower urinary levels of NAG at 18 h postoperatively (P = 0.008), and NGAL at sternum closure (P = 0.010), 2 h (P < 0.001) and 18 h (P = 0.015) postoperatively. Short-term PP in elderly patients showed higher safety for renal physiology than NP, resulting in better maintenance of glomerular filtration and lower renal tissue injury.

Comparative Effects of Pulsatile and Nonpulsatile Flow on Plasma Fibrinolytic Balance in Pediatric Patients Undergoing Cardiopulmonary Bypass

In the brain, the components of the fibrinolytic system, tissue plasminogen activator (tPA) and its endogenous inhibitor plasminogen activator inhibitor-1 (PAI-1), regulate various neurophysiological and pathological responses. Fibrinolytic balance depends on PAI-1 and tPA concentrations. The objective of this study is to compare the effects of pulsatile and nonpulsatile perfusion on fibrinolytic balance in children undergoing pediatric cardiopulmonary bypass (CPB). Plasma PAI-1 antigen and tPA antigen were measured in 40 children (n = 20 pulsatile and n = 20 nonpulsatile group). Plasma samples (1.5 mL) were collected (i) prior to incision, (ii) 1 h after CPB, and (iii) 24 h after CPB. PAI-1 and tPA levels were measured at each time point. PAI-1 and tPA levels were significantly increased at 1 h after CPB, followed by a decrease at 24 h. Nonpulsatile but not pulsatile CPB lowered PAI-1 : tPA ratio significantly at 24 h (median PAI-1 : tPA ratio 4.63 ± 0.83:1.98 ± 0.48, P = 0.03, for the nonpulsatile group and 4.50 ± 0.92:3.56 ± 1.28, P = 0.2, for the pulsatile group). These results suggest that pulsatile flow maintains endogenous fibrinolytic balance after pediatric cardiopulmonary bypass. Further studies are needed to define the clinical significance of these differences.

An evaluation of renal functions in pulsatile and non-pulsatile cardiopulmonary bypass in the elderly

An evaluation of renal functions in pulsatile and non-pulsatile cardiopulmonary bypass in the elderly

Microvascular fluid exchange during pulsatile cardiopulmonary bypass perfusion with the combined use of a nonpulsatile pump and intra-aortic balloon pump

To evaluate how pulsed versus nonpulsed cardiopulmonary bypass influences microvascular fluid exchange in an experimental setup combining a nonpulsatile perfusion pump and an intra-aortic balloon pump. A total of 16 pigs were randomized to pulsatile cardiopulmonary bypass perfusion with an intra-aortic balloon pump switched to an automatic 80 beats/min mode after the start of cardiopulmonary bypass (pulsatile perfusion [PP] group, n=8) or to nonpulsatile cardiopulmonary bypass with the pump switched to the off position (nonpulsatile [NP] group, n=8). Normothermic cardiopulmonary bypass was initiated after 60 minutes of stabilization and continued for 3 hours. The fluid needs, plasma volume, colloid osmotic pressure in plasma, colloid osmotic pressure in interstitial fluid, hematocrit, and total tissue water content were recorded, and the protein masses and fluid extravasation rates were calculated. After cardiopulmonary bypass was started, the mean arterial pressure increased in the PP group and decreased in the NP group. At 180 minutes, the mean arterial pressure of the PP and NP groups was 70.9 ± 2.7 mm Hg and 55.9 ± 2.7 mm Hg, respectively (P=.004). The central venous pressure (right atrium) had decreased in the NP group (P=.002). A decreasing trend was seen in the PP group. No between-group differences were present. The hematocrit and colloid osmotic pressure in plasma and interstitial fluid had decreased similarly in both study groups during cardiopulmonary bypass. The plasma volume of the PP group had decreased initially but then returned gradually to precardiopulmonary bypass levels. In the NP group, the plasma volume remained contracted (P=.02). No significant differences in the fluid extravasation rate were obtained. The fluid extravasation rate of the PP group tended to stay slightly higher than the fluid extravasation rate of the NP group at all measurement intervals. The total tissue water content increased significantly in a number of organs compared with that in the control animals. However, differences in the total tissue water content between pulsed and nonpulsed perfusion were absent. No significant differences in the fluid extravasation rates were present between pulsed and nonpulsed cardiopulmonary bypass perfusion in the present experimental setup.

Gaseous Micro‐Emboli Activity During Cardiopulmonary Bypass in Adults: Pulsatile Flow Versus Nonpulsatile Flow

Cardiopulmonary bypass (CPB) has a risk of cerebral injury, with an important role of gaseous micro-emboli (GME) coming from the CPB circuit. Pulsatile perfusion is supposed to perform specific conditions for supplementary GME activity. We aimed to determine whether pulsatile CPB augments production and delivery of GME and evaluate the role of different events in GME activity during either type of perfusion. Twenty-four patients who underwent on-pump coronary artery bypass grafting surgery at the University of Verona were divided equally into two groups-pulsatile perfusion (PP) group and nonpulsatile perfusion (NP) group. The circuit included a JostraHL-20 roller pump set in pulsatile or nonpulsatile mode, an open Sorin Synthesis membrane oxygenator with integrated screen-type arterial filter, and phosphorylcholine-coated tubes. Hemodynamic flow evaluation was performed in terms of energy equivalent pressure and surplus hemodynamic energy (SHE). GME were counted by means of a GAMPT BCC200 bubble counter (GAMPT, Zappendorf, Germany) with two probes placed at postpump and postarterial filter positions. Results were evaluated in terms of GME number, GME volume, number of over-ranged GME from both probes, and series of filtering indexes. In PP mode, the pump produced and delivered along the circuit significantly higher amounts of SHE than in NP mode. At the venous postpump site, GME number was significantly higher during PP but no difference was found in terms of GME volume or number of over-ranged bubbles. No significant difference in GME number, GME volume, or number of over-ranges was found at the postarterial filter site. Filtering indexes were similar between the two groups. Neither type of perfusion was shown to contribute to excessive GME production during the most important perfusionist manipulation. Pulsatility leads to GME increment by splitting and size diminishing of the existing bubbles but not by additional gas production. PP augmented GME number at the venous postpump site, while mean volume remained comparable with NP. Sorin Synthesis oxygenator showed high efficacy in GME removal during either type of perfusion. Supplementary GME production and delivery during typical perfusionist manipulations did not depend on perfusion type.

Comparison of the effects of pulsatile cardiopulmonary bypass, non-pulsatile cardiopulmonary bypass and off-pump coronary artery bypass grafting on the respiratory system and serum carbonyl

We aimed to investigate the effects of off-pump coronary artery bypass grafting (CABG), pulsatile cardiopulmonary bypass (CPB), and non-pulsatile CPB techniques on oxidative stress and the respiratory system in the current study. The patients were allocated into three different groups according to perfusion techniques, as follows: off-pump CABG group (n=10); pulsatile CPB (n=11); and non-pulsatile CPB group (n=11). Serum carbonyl level was measured and a pulmonary function test was performed preoperatively and postoperatively. The postoperative increase in the carbonyl level was significantly lower in the off-pump CABG group compared to the other two groups, while there was no significant difference between the pulsatile and non-pulsatile CPB groups with respect to carbonyl levels. Arterial partial pressure of oxygen, forced expiratory volume in one second, and forced vital capacity were significantly higher in the off-pump CABG group compared to other two groups in the postoperative period. We found that off-pump CABG had less negative effects on oxidative stress and the respiratory system compared to pulsatile CPB and non-pulsatile CPB techniques. Additionally, there was no significant difference between pulsatile and non-pulsatile CPB.

The Effects of Pulsatile Cardiopulmonary Bypass on Acute Kidney Injury

Protective effect of pulsatile flow cardiopulmonary bypass (CPB) on the occurrence of acute renal injury is still a matter of debate. The objective of this study was to compare the effects of pulsatile and non-pulsatile cardiopulmonary bypass on kidneys using Urinary neutrophil gelatinase-associated lipocalin (NGAL) and interleukin-18 (IL-18) as the markers of renal injury. 85 consecutive patients with normal preoperative renal function were prospectively enrolled in the study. Pulsatile perfusion (Group P) and non-pulsatile perfusion (Group NP) was used in 42 and 43 of the patients, respectively, during aortic cross-clamping period. NGAL and IL-18 were analyzed using ELISA in urine samples obtained preoperatively, and at 2, 12, and 24 h after CPB. There was no significant difference between the groups in terms of perioperative renal function tests. IL-18 levels measured at 12 h after CPB were significantly lower in Group P, compared to Group NP (p<0.05). Urinary NGAL levels measured at 2 and 12 h were higher in Group NP; however, the difference was insignificant. In the subgroup of patients with a cross clamp time ≥45 minutes (pulsatile CPB, group P1, n = 33; non-pulsatile CPB, group NP1, n = 33), IL-18 levels measured at 12 hours after CPB were significantly lower in Group P1. Urinary NGAL concentrations measured at 2 and 12 hours in Group P1 were also significantly lower than that in Group NP1 (p = 0.048 and 0.043, respectively). Low IL-18 and NGAL levels found in the pulsatile perfusion group might suggest the use of pulsatile flow resulted in better kidney protection.

Pulsatile flow during cardiopulmonary bypass preserves postoperative microcirculatory perfusion irrespective of systemic hemodynamics

The onset of nonpulsatile cardiopulmonary bypass is known to deteriorate microcirculatory perfusion, but it has never been investigated whether this may be prevented by restoration of pulsatility during extracorporeal circulation. We therefore investigated the distinct effects of nonpulsatile and pulsatile flow on microcirculatory perfusion during on-pump cardiac surgery. Patients undergoing coronary artery bypass graft surgery were randomized into a nonpulsatile (n = 17) or pulsatile (n = 16) cardiopulmonary bypass group. Sublingual mucosal microvascular perfusion was measured at distinct perioperative time intervals using sidestream dark field imaging, and quantified as the level of perfused small vessel density and microvascular flow index (vessel diameter < 20 μm). Microcirculation measurements were paralleled by hemodynamic and free hemoglobin analyses. The pulse wave during pulsatile bypass estimated 58 ± 17% of the baseline blood pressure waveform. The observed reduction in perfused vessel density during aorta cross-clamping was only restored in the pulsatile flow group and increased from 15.5 ± 2.4 to 20.3 ± 3.7 mm/mm(2) upon intensive care admission (P < 0.01). The median postoperative microvascular flow index was higher in the pulsatile group [2.6 (2.5-2.9)] than in the nonpulsatile group [2.1 (1.7-2.5); P = 0.001]. Pulsatile flow was not associated with augmentation of free hemoglobin production and was paralleled by improved oxygen consumption from 70 ± 14 to 82 ± 16 ml·min(-1)·m(-2) (P = 0.01) at the end of aortic cross-clamping. In conclusion, pulsatile cardiopulmonary bypass preserves microcirculatory perfusion throughout the early postoperative period, irrespective of systemic hemodynamics. This observation is paralleled by an increase in oxygen consumption during pulsatile flow, which may hint toward decreased microcirculatory heterogeneity during extracorporeal circulation and preservation of microcirculatory perfusion throughout the perioperative period.

Pulsatile Cardiopulmonary Bypass With Intra-Aortic Balloon Pump Improves Organ Function and Reduces Endothelial Activation

We aimed to evaluate if the use of an intra-aortic balloon pump (IABP) during cardioplegic arrest improves organ function and reduces endothelial activation in patients undergoing coronary artery bypass graft (CABG). Five-hundred and one CABG patients were randomized into 2 groups: (Group A n=270) linear cardiopulmonary bypass (CPB); and (Group B n=231) automatic 80 beats/min IABP-induced pulsatile CPB. We evaluated hemodynamic response, coagulation and fibrinolysis, transaminase, bilirubin, amylase, lactate, renal function (estimated glomerular filtration rate [eGFR], creatinine and any possibility of renal insufficiency or failure), respiratory function and endothelial markers (vascular endothelial growth factor [VEGF] and monocyte chemotactic protein-1 [MCP-1]). IABP, which induced surplus hemodynamic energy, was 21,387 ± 4,262 ergs/cm(3). Group B showed lower chest drainage, transfusions, international normalized ratio, and antithrombin III, together with higher platelets, activated partial thromboplastin time, fibrinogen and D-dimer. Transaminases, bilirubin, amylase, lactate were lower in Group B; there were better results for eGFR in Group B from ICU-arrival to 48 h, resulting in lower creatinine from ICU-arrival to 48 h. The necessity for renal replacement therapy was lower in Group B Stage-3. Group B P(a)O(2)/F(i)O(2) and lung compliance improved with aortic de-clamping on the first day with shorter intubation time. Group B showed lower VEGF and MCP-1. Pulsatile flow by IABP improves whole-body perfusion and reduces endothelial activation during CPB.

Novel Strategy to Improve End-Organ Function With Pulsatile Cardiopulmonary Bypass

Novel Strategy to Improve End-Organ Function With Pulsatile Cardiopulmonary Bypass

Comparison of Parameters for Detection of Splanchnic Hypoxia in Children Undergoing Cardiopulmonary Bypass With Pulsatile Versus Nonpulsatile Normothermia or Hypothermia During Congenital Heart Surgeries

The aim of this study is to evaluate gastric mucosal oxygenation together with whole-body oxygen changes in infants undergoing congenital heart surgery with cardiopulmonary bypass (CPB) procedure and the use of either pulsatile or nonpulsatile mode of perfusion with normothermia and pulsatile or nonpulsatile moderate hypothermia. Sixty infants undergoing congenital cardiac surgery were randomized into four groups as: nonpulsatile normothermia CPB (NNCPB, n = 15), pulsatile normothermia CPB (PNCPB, n = 15), nonpulsatile moderate hypothermia CPB (NHCPB, n = 15), and pulsatile moderate hypothermia CPB (PHCPB, n = 15) groups. In NNCPB and PNCPB groups, mild hypothermia was used (35°C), whereas in NHCPB and PHCPB groups, moderate hypothermia (28°C) was used. Gastric intramucosal pH (pHi), whole-body oxygen delivery (DO(2)) and consumption (VO(2)), and whole-body oxygen extraction fraction were measured at sequential time points intraoperatively and up to 2 h postoperatively. The measurement of continuous tonometry data was collected at desired intervals. The values of DO(2), VO(2), and whole-body oxygen extraction fraction were not different between groups before CPB and during CPB, whereas the PNCPB group showed higher values of DO(2), VO(2), and whole-body oxygen extraction fraction compared to the other groups at the measurement levels of 20 and 60 min after aortic cross clamp, end of CPB, and 2 h after CPB (P < 0.0001). Between groups, no difference was observed for pHi, lactate, and cardiac index values (P > 0.05). This study shows that the use of normothermic pulsatile perfusion (35°C) provides better gastric mucosal oxygenation as compared to other perfusion strategies in neonates and infants undergoing congenital heart surgery with CPB procedures.

Comparison of the effects of pulsatile cardiopulmonary bypass, non-pulsatile cardiopulmonary bypass and off-pump coronary artery bypass grafting on the inflammatory response and S-100beta protein

We aimed to investigate the effects of off-pump coronary artery bypass grafting, pulsatile cardiopulmonary bypass, and non-pulsatile cardiopulmonary bypass techniques on the inflammatory response and the central nervous system in the current study. A total of 32 patients who were scheduled for elective coronary artery bypass graft surgery were included in the study. The patients were allocated into three different groups according to the perfusion techniques used during the cardiopulmonary bypass procedure as follows: off-pump coronary artery bypass grafting group (n=10); pulsatile cardiopulmonary bypass group (n=11); and non-pulsatile cardiopulmonary bypass group (n=11). Serum interleukin-6, interleukin-8, tumor necrosis factor-alpha and S-100beta levels were measured preoperatively, and at 0, 6, and 24 hours postoperatively. The postoperative increase in the levels of interleukin-6 and interleukin-8 was significantly lower in the off-pump group compared to the other two groups (p<0.05), while there was no significant difference in tumor necrosis factor-alpha levels between the groups. Postoperative S-100β levels, an indicator of cerebral injury, was significantly lower in the off-pump CABG group compared to the other two groups (p<0.05). We found that off-pump coronary artery bypass grafting had less negative effects on inflammatory response and central nervous system compared to pulsatile cardiopulmonary bypass and non-pulsatile cardiopulmonary bypass techniques.

Clinical Effectiveness of Centrifugal Pump to Produce Pulsatile Flow During Cardiopulmonary Bypass in Patients Undergoing Cardiac Surgery

Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate whether the Rotaflow centrifugal pump produces effective pulsatile flow during CPB and whether the pulsatile flow in this setting is clinically effective in adult patients undergoing cardiac surgery. Thirty-two patients undergoing CPB for elective coronary artery bypass grafting were randomly allocated to a pulsatile perfusion group (n = 16) or a nonpulsatile perfusion group (n = 16). All patients were perfused with the Rotaflow centrifugal pump. In the pulsatile group, the centrifugal pump was adjusted to the pulsatile mode (60 cycles/min) during aortic cross-clamping, whereas in the nonpulsatile group, the pump was kept in its nonpulsatile mode during the same period of time. Compared with the nonpulsatile group, the pulsatile group had a higher pulse pressure (P <0.01) and a fraction higher energy equivalent pressure (EEP, P = 0.058). The net gain of pulsatile flow, represented by the surplus hemodynamic energy (SHE), was found much higher in the CPB circuit than in patients (P <0.01). Clinically, there was no difference between the pulsatile and nonpulsatile groups with regard to postoperative acute kidney injury, endothelial activation, or inflammatory response. Postoperative organ function and the duration of hospital stay were similar in the two patient groups. In conclusion, pulsatile CPB with the Rotaflow centrifugal pump is associated with a small gain of EEP and SHE, which does not seem to be clinically effective in adult cardiac surgical patients.

Effects of Pulsatile and Nonpulsatile Perfusion on Cerebral Regional Oxygen Saturation and Endothelin‐1 in Tetralogy of Fallot Infants

Although benefits of pulsatile flow during cardiopulmonary bypass (CPB) in pediatric heart surgery remain controversial and nonpulsatile CPB is still widely used in clinical cardiac surgery, pulsatile CPB must be reconsidered due to its physiologic features. In this study, we aimed to evaluate the effects of pulsatile perfusion (PP) and nonpulsatile perfusion (NP) on cerebral regional oxygen saturation (rSO₂) and endothelin-1 (ET-1) in pediatric tetralogy of Fallot (TOF) patients undergoing open heart surgery with CPB. Forty pediatric patients were randomly divided into the PP group (n = 20) and the NP group (n = 20). Pulsatile patients used a modified roller pump during the cross-clamp period in CPB, while NP patients used a roller pump with continuous flat flow perfusion. The subjects were monitored for rSO₂ from the beginning of the operation until 6 h after returning to the intensive care unit (ICU). We also monitored the hemodynamic status and ET-1 concentration and plasma free hemoglobin (PFH) in blood samples of all patients over time. Effective PP was monitored in PP patients, and pulse pressure was significantly higher in the PP group than in the NP group (P < 0.01). rSO₂ of the PP group was higher than that of the NP group (P < 0.01) during the cross-clamp period, and this advantage of PP would be maintained until 2 h after patients returned to the ICU (P < 0.05). ET-1 level in blood samples was lower at clamping off and CPB weaning and early ICU period in the PP group than in the NP group (P < 0.01), and ET-1 concentration remained at a normal level after patients were transferred to the ICU 24 h in all patients. PFH levels in the PP group at pre-clamp off and CPB weaned off were higher than those of the NP group (P < 0.05) in these cyanotic patients. PP can increase rSO₂ and improve microcirculation during cross-clamping period in TOF pediatric patients, while PP resulted in more severe hemolysis in these cyanotic patients than NP.

Clinical Effectiveness of Centrifugal Pump to Produce Pulsatile Flow During Cardiopulmonary Bypass in Patients Undergoing Cardiac Surgery

Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate whether the Rotaflow centrifugal pump produces effective pulsatile flow during CPB and whether the pulsatile flow in this setting is clinically effective in adult patients undergoing cardiac surgery. Thirty-two patients undergoing CPB for elective coronary artery bypass grafting were randomly allocated to a pulsatile perfusion group (n = 16) or a nonpulsatile perfusion group (n = 16). All patients were perfused with the Rotaflow centrifugal pump. In the pulsatile group, the centrifugal pump was adjusted to the pulsatile mode (60 cycles/min) during aortic cross-clamping, whereas in the nonpulsatile group, the pump was kept in its nonpulsatile mode during the same period of time. Compared with the nonpulsatile group, the pulsatile group had a higher pulse pressure (P < 0.01) and a fraction higher energy equivalent pressure (EEP, P = 0.058). The net gain of pulsatile flow, represented by the surplus hemodynamic energy (SHE), was found much higher in the CPB circuit than in patients (P < 0.01). Clinically, there was no difference between the pulsatile and nonpulsatile groups with regard to postoperative acute kidney injury, endothelial activation, or inflammatory response. Postoperative organ function and the duration of hospital stay were similar in the two patient groups. In conclusion, pulsatile CPB with the Rotaflow centrifugal pump is associated with a small gain of EEP and SHE, which does not seem to be clinically effective in adult cardiac surgical patients.

Anti-inflammatory response and cardiopulmonary bypass: reply to Denizot and Nathan

We read with a great interest the excellent article by Onorati and co-workers demonstrating that pulsatile cardiopulmonary bypass (PCPB) and off-pump coronary artery bypass (OPCAB) surgery markedly reduced endothelial activation and inflammatory response as compared with linear CPB [1]. What about anti-inflammatory cytokines (except interleukin (IL)-10 already investigated in this study)? Studies have demonstrated that both inflammatory/anti-inflammatory cytokines and growth factors/antigrowth factors are released during conventional CPB [2—5]. Anti-inflammatory cytokines and anti-growth factors (sFlt-1) are considered as an anti-inflammatory response against CPB-induced inflammatory changes. The authors might use their collected blood samples to search for IL-4, IL-13, soluble IL-6 receptor and soluble vascular endothelial growth factor (VEGF) receptor (sFlt-1) and to identify whether the anti-inflammatory response is also impaired during PCPB and OPCAB as compared with linear CPB.