Do S100beta protein level increases due to inflammation during cardiopulmonary bypass occur without any neurological deficit?

PURPOSE: S100beta protein level correlates with the duration of cardiopulmonary bypass (CPB) and aortic crossclamp times, but is different during pulsatile and nonpulsatile CPB. In this study, we investigated the time course of the release of S100beta protein during and after pulsatile and nonpulsatile CPB. PATIENTS AND METHODS: This is a prospective study. Twenty patients had open-heart surgery with pulsatile flow and 20 with nonpulsatile flow. We compared complement proteins, interleukins, white blood cells and S100beta protein before the initiation of CPB, immediately prior to aortic crossclamping, following unclamping, and at postoperative 1st and 24th hours. RESULTS: In the pulsatile CPB group following aortic unclamping, S100beta protein (p = 0.028) and C3a (p = 0.011) levels were significantly lower than those of the nonpulsatile group. In the pulsatile CPB group at postoperative first hour, C3a level (p = 0.018) and absolute neutrophil count (p = 0.034) were significantly lower than those of the nonpulsatile group. None of the patients developed a neurological deficit and all of the patients survived after the operation and were discharged from the hospital. CONCLUSION: During CPB, serum S100beta protein level increases and this increase is higher in the nonpulsatile group. High serum level of S100beta protein is associated with increased levels of serum inflammatory mediators and systemic inflammatory response.     

Should we rely on nasopharyngeal temperature during cardiopulmonary bypass?

A potential morbidity of incomplete re-warming following hypothermic cardiopulmonary bypass (CPB) is cardiac arrest. In contrast, attempts to fully re-warm the patient can lead to cerebral hyperthermia. Similarly, rigid adherence to 37.0 degrees C during normothermic CPB may also cause cerebral overheating. The literature demonstrates scant information concerning the actual temperatures measured, the sites of temperature measurement and the detailed thermal strategies employed during CPB. A prospective, randomized, controlled study was undertaken to investigate the ability to manage perfusion temperature control in a group of hypothermic patients (28 degrees C) and a group of normothermic patients (37 degrees C). Eighty patients presenting for first-time, elective coronary artery bypass graft surgery (CABG) were randomly allocated to the hypothermic and normothermic groups. All surgery was performed by one surgeon and the anaesthesia managed by one anaesthetist. Temperature measurements were made at the nasopharyngeal (NP) site, as well as in the arterial line of the CPB circuit. The hypothermic group had the arterial blood temperature lowered to 25.0 degrees C to maintain the NP temperature at 28.0-28.5 degrees C. During re-warming, the arterial blood was raised to 38.0 degrees C. Meanwhile, in the normothermic group, the arterial blood temperature was raised to a maximum of 37.0 degrees C to maintain NP temperature at 36.5-37.0 degrees C. Despite strict guidelines, some patients transgressed the temperature control limits. Two patients in the hypothermic group failed to reach an NP temperature of 28.5 degrees C. Twenty-six patients were managed entirely within the control limits. During rewarming in both groups, control of both arterial and NP temperature was well managed with only 25% patients breaching the respective upper control limits. During the re-warming phases of CPB, we were unable to make any correlation between NP temperature and arterial blood temperature, using body weight or body mass index as predictors. Based on the results obtained, we recommend that strict criteria should be implemented for the management of temperature during CPB, in conjunction with more emphasis being placed on monitoring arterial blood temperature as a marker of potential cerebral hyperthermia. We should, therefore, not rely on NP temperature measurement alone during CPB.     

The influence of pulsatile and nonpulsatile extracorporeal circulation on fluid retention following coronary artery bypass grafting

Thirty male patients undergoing coronary artery bypass grafting were divided into two groups, group I receiving pulsatile perfusion, group II nonpulsatile perfusion. A double roller pump system for extracorporeal circulation was employed. Intra- and postoperative fluid balances and bodyweight gains were controlled under clinical conditions. There were no significant differences between the groups with regard to clinical data, operative procedure, perfusion parameters, drug treatment or intensive care treatment. The intra-operative mean fluid balance of group I was 794.0ml (66%) lower than that of group II, while the balance 24 hours postoperatively was 136.7ml (37%) lower in group I. Thus, the total mean fluid balance for the pulsatile group was 931.0ml (59%) lower than the nonpulsatile group, in accordance with the bodyweights, which showed a 954.0g (63%) lower outcome in the pulsatile group. Less supplementary volume and higher urine production were the main factors. It appears that volume saved during pulsatile ECC need not be replaced postoperatively. These findings indicate that pulsatile perfusion leads to diminished fluid overloading, which could be an important advantage, especially for high-risk patients.     

Comparison of the standard roller pump and a pulsatile centrifugal pump for extracorporeal circulation during routine coronary artery bypass grafting

The present prospective study compared the standard nonpulsatile twin roller pump with the Sarns centrifugal pump, in the pulsatile mode, as arterial pumps for extracorporeal circulation during coronary artery bypass grafting (CABG). The study was conducted in two consecutive groups of 25 patients receiving a standard anaesthetic and surgical protocol. The investigated parameters included haemodynamic profiles, oxygen exchange, blood gas and acid-base homeostasis, haematology, coagulation and complement consumption. With comparable settings for pump flow, gas flow and delivered oxygen concentrations, there was no difference between the groups in the main haemodynamic parameters during cardiopulmonary bypass (CPB). However, a tenfold lower dose of sodium nitroprusside was required to keep systemic vascular resistance within physiologic limits during CPB in the centrifugal group (C group) compared with the roller group (R group). During rewarming oxygen extraction was higher in the C group than in the R group. During the first eight hours after CPB no differences in haemodynamics, oxygenation parameters and pulmonary shunt between the groups were observed. During, as well as after, CPB there was no significant difference in blood gas and acid-base homeostasis between either group. Average postoperative blood loss via chest tubes, total transfusions of blood products, haemoglobin and coagulation did not differ between the two groups. However, the white blood cell count, corrected for changes in haematocrit, decreased during the early phase of CPB in the R group, but not in the C group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in metabolism and blood flow in peripheral tissue (skeletal muscle) during cardiac surgery with cardiopulmonary bypass: the biochemical microdialysis study

The aim of this study was to monitor the metabolism and blood flow in the interstitium of the skeletal muscle during cardiac surgery with cardiopulmonary bypass (CPB) and in the early postoperative period by means of microdialysis and to compare metabolic changes during CPB at normothermia (NT) and hypothermia (HT). Surgical revascularization using CPB was performed in 50 patients, 25 patients (group HT) were operated using hypothermic CPB, 25 (group NT) using normothermic CPB. Interstitial microdialysis was performed by two CMA 60 probes (CMA Microdialysis AB, Solna, Sweden) inserted into the patient's deltoid muscle. Constituents analysed in the obtained dialysates, collected at intervals, were glucose, urea, glycerol and lactate. Tissue blood flow was monitored by dynamic microdialysis with gentamicin as a marker. In both groups, NT versus HT, similar dynamics of concentrations were found. Low initial concentrations were followed by gradual increases during CPB and in the following phase of the operation. Concentrations were higher in the NT group. Immediately after the operation, the decrease in values continued, with a gradual increase in the succeeding postoperative period in both groups. Similar dynamic changes in the lactate concentration were found in both groups. The gentamicin concentrations were lower in the NT group (versus the HT group). The results showed dynamic changes in the interstitial concentrations of glucose, urea, glycerol and lactate, which depend on the phase of the surgery in the CPB and early postoperative phase in the both groups of patients. Higher tissue perfusion of the skeletal muscle was noted in those patients operated on in normothermia. The dynamics of the concentration changes of these substances in the interstitium of the skeletal muscle has been proven to be caused by both the metabolic activity of the tissue and by the blood flow through the interstitium of the muscle.     

体外循环行肺动脉灌注液对术后肺功能的保护

目的探讨体外循环(CPB)期间行肺动脉灌注液对术后肺功能的保护作用。方法 2007年1月-2011年4月30例在CPB下行单纯二尖瓣人工机械瓣置换术患者,随机分成肺保护组和对照组各15例,肺保护组患者CPB期间经肺动脉灌注低温肺保护液,对照组患者CPB期间未经肺动脉灌注低温肺保护液。监测两组患者在麻醉诱导后、阻断主动脉l0 min及开放主动脉l0 min,2、12、24 h各时间点的呼吸指数(RI)、氧合指数(OI)、白介素6(IL-6)、肿瘤坏死因子α(TNF-α)及术前、术后肺动脉压力(PAPm)、静态肺顺应性(CLS)、气道阻力(AR)变化,并比较术后ICU监护时间、术后呼吸机辅助时间、住院天数及有无术后并发症等。结果两组IL-6、TNF-α、RI、OI、PAPm、AR、CLS比较差异均有统计学意义(P<0.05)。但术后ICU监护时间及住院时间比较差异均无统计学意义(P>0.05)。结论 CPB期间行肺动脉灌注对术后肺功能具有保护作用。     

Impact of membrane oxygenators on pulsatile versus nonpulsatile perfusion in a neonatal model

We investigated the effects of two new hollow-fiber membrane oxygenators, the Capiox SX10 and the Lilliput 901, on pulsatile versus nonpulsatile perfusion in an in vitro model designed to simulate a 3 kg infant. The experiments were divided into eight groups (six pulsatile and two nonpulsatile), according to the equipment and settings used. Each group included six tests. In all experiments, the pseudo-patient's mean arterial pressure was 40 mmHg, and the pump flow rate was 550 ml/min. During pulsatile cardiopulmonary bypass, the pump's base flow was set at 30%, and the pump rate was set at 80, 100, 120, 140, or 150 beats/min. The PUMP START and PUMP STOP timing points were adjusted to produce different pulse-width settings. We were especially interested in evaluating the pre- and postoxygenator extracorporeal circuit pressure (ECP), the oxygenator pressure drop, and the precannula ECP. When used with a pulsatile roller pump, the Capiox produced a significantly lower preoxygenator ECP than the Lilliput (p < 0.001); moreover, the Capiox yielded a significantly lower oxygenator pressure drop (p < 0.001). During nonpulsatile perfusion, the Capiox again produced a lower preoxygenator ECP than the Lilliput (p < 0.001). These results suggest that the Capiox may be more suitable than the Lilliput when the pulsatile flow is employed, and pulsatile flow does not increase the ECP with either oxygenator.     

Factors influencing the change in cerebral hemodynamics in pediatric patients during and after corrective cardiac surgery of congenital heart diseases by means of full-flow cardiopulmonary bypass

BACKGROUND: The pathophysiology of hypoxic-ischemic brain injury in relation to extracorporeal circulation is multifactorial and can be interpreted, in part, as possible alteration in cerebral perfusion and inadequate oxygen delivery to the brain cells. The aim of this study was to evaluate influencing factors on the change in cerebral blood flow velocity (CBFV) patterns determined by transcranial Doppler sonography (TCD) in infants who undergo corrective cardiac surgery by means of full-flow cardiopulmonary bypass (CPB). METHODS: Included in the study were 67 neonates, infants, and children with a median age of 4 months (0.1-70 months), median weight of 4.8 kg (2.5-18.8 kg), and with cyanotic and noncyanotic congenital heart disease (CHD), who underwent surgical correction of CHD by means of CPB [flow rate 144 +/- 47 ml/kg body weight (BW)] and the alpha-stat strategy. The patients were divided into three groups with respect to the minimum rectal temperature during perfusion: deep hypothermic CPB (<18 degrees C) n=18, moderate hypothermic CPB (22-35 degrees C) n=29, normothermic CPB (36 degrees C) n=20. Continuous determination of mean flow velocity (Vmean) in the middle cerebral artery (MCA) by TCD provided qualitative on-line information on cerebral perfusion. The pulsatility index (PI) was calculated in accordance with the formula: Maximum flow velocity - end - diastolic flow velocity/ Mean flow velocity and was used as a parameter for the qualitative assessment of cerebrovascular resistance after the end of CPB. RESULTS: The Vmean was significantly increased 15 min after cross-clamping in the normothermic group (p=0.03) and decreased in the moderate hypothermic group (p=0.02) and deep hypothermic group (p=0.009). The postoperative Vmean values correlated significantly with age (r=0.79, p<0.0001), weight (r=0.75, p<0.0001), bypass time (r=-0.51, p=0.0006), and minimum rectal temperature (r=0.60, p=0.0001). Mean arterial pressure and hemoglobin concentration, but not pCO2, seem to significantly influence the change in Vmean after the termination of CPB (r=0.5, p=0.001; r=-0.55, p=0.002, respectively). In comparison with the values at the start of CPB, the Vmean was significantly decreased after the end of CPB in the hypothermic and moderate hypothermic groups and still significantly elevated in the normothermic group. The age-independent PI was increased after termination of bypass in all groups (p<0.05) and still slightly elevated after the end of operation in the hypothermic group (p=0.05). CONCLUSIONS: The changes in CBFV patterns before, during, and after the termination of CPB were dependent on age, weight, perfusion pressure, and degree of hypothermia during CPB.     

The effect of oxygenator mechanical characteristics on energy transfer during clinical cardiopulmonary bypass

The hollow-fibre oxygenator is a key component of any extracorporeal circuit used to provide cardiopulmonary bypass (CPB) during open-heart surgery. Since the oxygenator is placed downstream of the pump, the energy losses over it have a direct impact on the quality of pulsatile pressure and flow waveforms. The objective of this study was to describe the effects of hydrodynamic characteristics of the oxygenator on energy transfer during pulsatile, normothermic CPB. Twenty-three adult patients scheduled for coronary bypass surgery were divided randomly into two groups, using either an oxygenator (Group 1) with a relatively high-resistance and low-compliance (2079 ± 148 dyn.s.cm(-5) and 0.00348 ± 0.00071 ml.mmHg(-1), respectively) or an oxygenator (Group 2) with a relatively low-resistance and high-compliance (884 ± 464 dyn.s.cm(-5) and 0.01325 ± 0.00161 ml.mmHg(-1), respectively). During perfusion, pre- and post-oxygenator pressures, radial artery pressure, and blood flow were recorded simultaneously. A 32% decline of mean pressure was observed in Group 1 and a 16% decline in Group 2 (p<0.0001). Another decrease by approximately 73% in mean pressure in the rest of the perfusion system was noted in both groups. The mean radial artery pressure did not differ between the groups (74 ± 6 mmHg in Group 1 and 73 ± 6 mmHg in Group 2, p=0.608). Although lower total energy transfer indices were noticed through the low-resistance oxygenator (Group 2), both oxygenators showed a decrease of the generated pump oscillatory energy of approximately 50%. Despite the differences in resistance and compliance of the hollow-fibre oxygenators used, both oxygenators cause a comparable loss of generated oscillatory energy. Exclusion of the oxygenator downstream of the pulsatile pump would improve energy transfer during CPB.     

A comparison of several variables of off-pump coronary artery bypass procedures versus myocardial revascularization utilizing cardiopulmonary bypass

An investigation was conducted to compare several variables of off-pump coronary artery bypass (OPCAB) procedures with those using cardiopulmonary bypass (CPB) for myocardial revascularization by two surgeons. The patients were divided into four groups: group 1 patients received CPB for their myocardial revascularization performed by surgeon A; group 2 patients received the OPCAB procedure performed by surgeon A; group 3 patients received CPB for their myocardial revascularization performed by surgeon B; and group 4 received the OPCAB procedure performed by surgeon B. The same anesthesia technique and postoperative management were employed for all patients in this study. The CPB procedures received the same perfusion circuit and conduct. Postoperative laboratory values, including hemoglobin, hematocrit and platelet counts for the OPCAB groups, were higher than the CPB groups. Chest tube drainage was similar for both the OPCAB and CPB groups, but postoperative urine outputs were significantly higher in the CPB groups for both surgeons. Positive fluid balance was statistically greater in the CPB groups compared to the OPCAB groups for both surgeons. Ventilator times, length of stay in the intensive care unit (ICU) and length of hospital stay were not statistically significant for the groups in this study. Postoperative weight gain for both surgeons was higher in the CPB groups. Intraoperative packed red blood cell (PRBC) usage for surgeon B was similar for both the OPCAB and CPB groups, but the OPCAB group for surgeon A had greater intraoperative PRBC usage than the CPB group.     

Impact of cardiopulmonary bypass management on postcardiac surgery renal function

OBJECTIVE: Cardiac surgery on cardiopulmonary bypass (CPB) is associated with postoperative renal dysfunction and up to 4% of patients with normal preoperative renal function develop acute renal failure (ARF) requiring dialysis. According to recent investigations, CPB management is not evidence-based and, thus, current clinical CPB practice may favor renal dysfunction. The purpose of our study was to investigate if postcardiac surgery renal dysfunction is influenced by CPB management. METHODS: We selected three groups of patients with normal preoperative renal function who had been subjected to cardiac surgical procedures on CPB: 44 patients with postoperative ARF requiring hemofiltration/dialysis (ARF group), 51 patients with postoperative renal dysfunction not requiring hemofiltration/dialysis (serum creatinine increase > 0.5 mg/dl within 48 h postsurgery: CREA group), and 48 patients with normal postoperative renal function (Control group). The patients' on-line CPB records were analyzed for CPB duration, CPB perfusion pressure, CPB flow, and periods on CPB at a perfusion pressure <60 mmHg. On-CPB diuretic and vasoconstrictor medication was recorded. RESULTS: Patient demographics were similar for the three groups. In the ARF group, CPB duration was longer (166 +/- 77 [standard deviation, SD] min) compared to CREA (115 +/- 41 min; p < 0.001) and to Control groups (107 +/- 40 min; p < 0.001), and mean CPB flow was lower (2.35 +/- 0.36 l/min/m2) compared to CREA (2.61 +/- 0.35 l/min/m2; p = 0.0015) and to Control groups (2.51 +/- 0.33 l/min/m2; p = 0.09). Mean arterial pressure on CPB (ARF: 61 +/- 10; CREA: 60 +/- 7; CONTROL: 63 +/- 9 mmHg; p = 0.19) as well as furosemide and norepinephrine medication on CPB were similar for the groups. Compared to Control (46 +/- 26 min), CPB duration at arterial pressures <60 mmHg was longer in ARF (78 +/- 60 min; p = 0.034) and in CREA (62 +/- 36 min;p = 0.048). CONCLUSIONS: Our data suggest that current clinical CPB management impacts postoperative renal function. We found that patients with normal preoperative renal function who developed postoperative ARF had longer CPB duration, lower CPB perfusion flow, and longer periods on CPB at pressures < 60 mmHg compared to patients with no post CPB ARF. However, our data do not allow us to separate these CPB-related factors from the potential influence of perioperative low cardiac output syndrome as a cause for postoperative ARF. Thus, future clinical studies are required to elucidate CPB-induced ARF and to optimize CPB management for ARF prevention.     

Intraoperative fluid balance during cardiopulmonary bypass: effects of different mean arterial pressures

INTRODUCTION: This study investigated whether two levels of mean arterial pressure (MAP) during cardiopulmonary bypass did influence per-operative fluid shifts. METHODS: Sixteen pigs underwent 60 minutes of normothermic cardiopulmonary bypass (CPB) followed by 90 minutes of hypothermic CPB. Eight animals had a MAP of 60-80mmHg by norepinephrine (HP group). Another 8 animals had a MAP of 40-45 mmHg by phentolamine (LP group). Blood chemistry, plasma/interstitial colloid osmotic pressures, plasma volume, fluid balance, fluid extravasation rate and tissue water content were measured or calculated. RESULTS: The plasma volume was significantly lower in the HP group compared with the LP group after 60 minutes of CPB. Net fluid balance was 0.18 (0.05) ml x kg(-1) x min(-1) in the HP group and 0.21 ml x kg(-1) x min(-1) in the LP group (P > 0.05) while fluid extravasation rate was 1.18 (0.5) and 1.13 (0.4) ml x kg(-1) x min(-1) in the HP group and the LP group during CPB (P > 0.05). CONCLUSION: Net fluid balance and fluid extravasation rate were similar in the animals with elevated and with lowered MAP during CPB.     

Changes in the liver circulation and kidney function during pulsatile and non-pulsatile perfusion

Pulsatile flow perfusion (PFP) requires smaller volume of additional infusion. Extravascular hyperhydration is more marked after nonpulsatile flow perfusion (NPFP). In NPFP there is an increase in free water clearance, lower urinary osmolality and diuresis rate. PFP prevents urinary hypoosmolality and retains baseline values of free water clearance. No significant differences in Na+ urinary excretion have been revealed. Bilirubinemia level following NPFP was significantly higher than the baseline level, while following PFP the level of total and bound bilirubin remained unchanged. No differences in the total hepatic flow have been observed during pulsatile and nonpulsatile flow perfusion.     

Effects of normothermia versus hypothermia on extravascular lung water and serum cytokines during cardiopulmonary bypass: a randomized, controlled trial

OBJECTIVE: To evaluate the influence of perfusion temperature on the systemic effects of cardiopulmonary bypass (CPB), including extravascular lung water index (EVLWI), and serum cytokines. DESIGN: Prospective, randomized, controlled study. SETTING: Cardiothoracic intensive care unit of a university hospital. PATIENTS: Patients undergoing elective coronary artery bypass grafting. INTERVENTIONS: Twenty-one patients undergoing elective coronary artery bypass grafting were randomly assigned to receive either normothermic bypass (36 degrees C, n = 8) with intermittent antegrade warm blood cardioplegia (IAWBC), or hypothermic (32 degrees C, n = 13) CPB with cold crystalloid cardioplegia. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure, heart rate, cardiac output, systemic vascular resistance, mean pulmonary arterial pressure, and pulmonary vascular resistance were determined at baseline, i.e., after induction of anesthesia but before sternal opening (T-1), at arrival in the intensive care unit (T0), and 4 hrs (T4), 8 hrs (T8), and 24 hrs (T24) after surgery. EVLWI, intrathoracic blood volume index (ITBVI), and EVLW/ITBV ratio were obtained by using thermal dye dilution utilizing an arterial thermistor-tipped fiberoptic catheter and were recorded at T-1, T0, T4, T8, and T24. Serial blood samples for cytokine measurements were obtained at each hemodynamic measurement time point. Before, during, and after CPB, there were no differences in the conventional hemodynamic measurements between the groups. There were no changes in EVLWI up to T8 in either group. Furthermore, no change in the ratio EVLW/ITBW was observed between the groups at any time, further indicating the absence of a change in pulmonary permeability. Plasma levels of interleukin-6, tumor necrosis factor-alpha, and interleukin-10 increased during and after CPB, independently of the perfusion temperature. CONCLUSION: Normothermic CPB is not associated with additional inflammatory and related systemic adverse effects regarding cytokine production and EVLWI as compared with mild hypothermia. The potential temperature-dependent release of cytokines and subsequent inflammation has not been observed and normothermic CPB may be seen as a safe technique regarding this issue.     

Effect of antegrade graft cardioplegia combined with passive graft perfusion in on-pump coronary artery bypass grafting

Patients undergoing on-pump coronary artery bypass graft (CABG) with proximal graft anastomosis were randomly divided into groups that received antegrade cardioplegic infusion only via the aortic root (group A) or antegrade cardioplegic infusion via the aortic root and additional cardioplegia via vein or free arterial grafts after completion of each distal anastomosis (group B). The group B patients also received bypass graft perfusion with warm arterial blood just after removal of the cross-clamp until the proximal graft anastomosis was completed. The need for defibrillation and inotropic support during separation from cardiopulmonary bypass (CPB), and total CPB time were significantly lower in group B than in group A. Group B also had significantly lower peak cardiac troponin I levels 12 h after operation compared with group A and this was more pronounced in subgroups with severe right coronary artery stenosis and poor left ventricular ejection fraction than in the whole population. It is concluded that antegrade graft cardioplegia and graft perfusion with warm blood during proximal graft anastomosis may improve myocardial protection.     

Leukocyte filtration in the early reperfusion phase on cardiopulmonary bypass reduces myocardial injury

Improved myocardial protection and cardiopulmonary bypass (CPB) have limited, but not abolished, intraoperative myocardial damage due to surgical reperfusion injury after release of the aortic crossclamp. In this double-blind, randomized study, we evaluated whether short-term leukocyte filtration during reperfusion may further reduce myocardial damage. Thirty-eight patients with coronary artery disease were randomly assigned to CPB with (group I; n = 19) or without leukocyte filtration (group II; n = 19). There was no difference in bypass time or crossclamp time between the groups. No patient in group I required catecholamines, whereas three patients in group II were supported with adrenaline or dobutamine on the first and second postoperative day. In addition, troponin T plasma levels were lower in group I (p < 0.05), whereas other markers for tissue injury (CK, CK-MB, LDH, S-GOT and S100B) did not differ. In conclusion, leukocyte filtration during reperfusion may further improve CPB by reducing myocardial damage.     

Comparison of hollow-fiber membrane oxygenators in terms of pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass in neonates

The objective of this study was to investigate the effects of two hollow-fiber membrane oxygenators, the Capiox SX10 and the Lilliput 901, on pressure drop of the membranes during normothermic and hypothermic cardiopulmonary bypass (CPB) in neonates. METHODS: Twenty-six congenital heart surgery patients (n = 13 in each group) with a mean weight of 3 kg were included in this study. Pressure drops of the membranes, pre- and post-oxygenator extracorporeal circuit pressures (ECC) were recorded during normothermic CPB, hypothermic CPB (20 degrees C) and after rewarming. There were no differences between the groups in mean arterial pressure, pump flow rate, temperature, duration of CPB, crossclamp time or the severity of the surgical repairs. RESULTS: Pressure drop of the Capiox SX10 oxygenator was significantly lower during normothermic (32 +/- 10 versus 55 +/- 16 mmHg, p < 0.001), hypothermic (38 +/- 15 versus 72 +/- 18 mmHg, p < 0.001) and post-rewarming (42 +/- 13 versus 72 +/- 21 mmHg, p < 0.001) periods compared to the Lilliput oxygenator. In the Capiox group, the pre-oxygenator ECC pressure was also significantly lower during normothermic CPB (142 +/- 27 versus 184 +/- 43 mmHg, p < 0.01), hypothermic CPB (162 +/- 30 versus 199 +/- 38 mmHg, p < 0.01) and after rewarming periods (172 +/- 32 versus 212 +/- 42 mmHg, p < 0.01). Post-oxygenator pressures in the Capiox group were also lower than in the Lilliput group, but results were not statistically significant. CONCLUSIONS: These results suggest that the Capiox SX10 hollow-fiber membrane oxygenator produced significantly lower membrane pressure drops and pre- and post-oxygenator ECC during normothermic and hypothermic CPB. Thus, blood trauma with the Capiox during extracorporeal circulation may be significantly lower compared to the Lilliput. Further studies, including the level of complements, platelets, neutrophils and cytokines, with these oxygenators are warranted.     

Early experience with a new technique and technology designed for the study of pulsatile cardiopulmonary bypass in the rat

The benefits of pulsatile flow during the period of cardiopulmonary bypass (CPB) applied during open-heart surgery remains controversial. We have developed a rodent (rat) model of CBP that has been designed to functionally mimic the clinical setting, principally, but not solely, for the study of pulsatile CPB. The successful development of this model centres on the design of the bypass circuitry and the surgical approach employed. The entire circuit is similar to clinical equipment in terms of its construction, configuration, performance, material surface area to blood volume ratio, and priming volume to blood volume ratio. The overall priming volume of the perfusion circuitry is less than 12 ml. Early studies confirm that the pumping technology functions well, gas exchange was adequate at all times, and blood pressure exhibited a normal CPB profile and haemodynanmic response to pulsatile blood flow. We conclude that this is an effective tool for investigating the pathophysiology of pulsatile blood flow during CPB.     

The effect of zero-balanced ultrafiltration during cardiopulmonary bypass on S100b release and cognitive function

Zero-balanced ultrafiltration (ZBUF) might reduce the systemic inflammatory response (SIRS) during cardiopulmonary bypass (CPB) by removing inflammatory mediators. The objective of this study was to determine the effect of ZBUF on postoperative serum S100b levels, a marker of neuronal injury. In addition, the possible effects of ZBUF on postoperative neurocognitive function were assessed. Sixty patients undergoing elective coronary bypass grafting were randomly assigned either to a control group or to a protocol group in which ZBUF was performed. Serum S100b levels were measured five minutes after intubation, at the end of bypass and eight and 20 hours after arrival at the intensive care unit (ICU). Cognitive function was assessed with neuropsychological tests on the day before the operation and the sixth day after surgery. The S100b level at 20 hours after arrival at the ICU was 0.27 g/L (SD 0.16) in the control and 0.25 g/L (SD 0.12) in the group with ZBUF. There were no statistical differences at any time between the two groups. S100b was not detectable in the ultrafiltrate, indicating that these results were not obscured by washout of S100b. Thirteen patients (52%) in the control group and 14 patients (56%) in the ZBUF group showed a cognitive deficit. In conclusion, ZBUF during CPB does not decrease the release of S100b. This result is not affected by washout. ZBUF did not reduce the incidence of early neurocognitive deficits. The role of SIRS in the development of cognitive dysfunction following CPB remains to be resolved.     

经肺动脉持续灌注低温含氧血及乌司他丁对肺的保护作用

目的:观察持续肺动脉灌注低温含氧血混和乌司他丁对肺功能的保护作用。方法:130例瓣膜病患者随机分为肺保护组70例,对照组60例。肺保护组在升主动脉阻断后,经主肺动脉持续灌注低温含氧血混和乌司他丁。对照组常规进行瓣膜置换手术。分别在麻醉诱导期、转流结束即刻、转流结束后6、12、24h取桡动脉血,应用放射免疫法测定肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)和白细胞介素-8(IL-8)水平;同时记录机械辅助通气时间。结果:两组患者体外循环后上述参数水平开始升高,24h仍高于术前(P<0.01),但肺保护组TNF-α、IL-6、IL-8水平上升幅度在各时间点均低于对照组(P<0.05或P<0.01)。肺保护组机械辅助通气时间显著低于对照组(P<0.01)。结论:持续肺动脉灌注低温含氧血混和乌司他丁能够减轻体外循环术后肺损伤。