Histamine release during cardiopulmonary bypass in neonates and infants

Purpose

Histamine release has been previously documented in adults and children during cardiopulmonary bypass (CPB). It has not been studied in neonates nor during deep hypothermic circulatory arrest (DHCA). Histamine effects could explain many penoperative complications of congenital cardiac surgery such as dysrhythmias and massive oedema. Therefore, documentation of histamine release in the penoperative period is of clinical importance. The source of histamine can be determined by measurement of tryptase which is released with histamine from mast cells but not basophils.

Methods

Blood samples for histamine and tryptase were taken before and after specific events eg. cross-damp removal, during anaesthesia and CPB in 14 infants and seven neonates undergoing complex congenital heart repairs and were analysed by commercial radiommunoassays. Haemodynamic variables and pre and post-op weights were recorded to look for correlation between pathophysiologcal events and histamine release.

Results

Histamine concentration decreased at the start of bypass (0.69 to 0.38 ng · ml^?1 at five minutes, (P < .005). There were no changes associated with DHCA and a small rise with reventilation (P < 0.02). Histamine concentration was lower in neonates than in infants (P < 0.05) during CPB. Plasma histamine and tryptase concentrations did not correlate, suggesting histamine release was from basophils and not from mast celts. Haemodynamic variables did not correlate with histamine concentrations.

Conclusion

There was no major histamine release during CPB in infants and neonates. There was no relationship between histamine concentrations and dinical variables. Histamine released during CPB appears to come from basophils and may be a function of age.     

Cerebral pressure-flow velocity relationship during hypothermic cardiopulmonary bypass in neonates and infants.

To examine the effect of temperature on the relationship between cerebral perfusion pressure (CPP) and cerebral blood flow velocity (CBFV) and the effect of low-flow cardiopulmonary bypass (CPB) on cerebral perfusion, we studied 25 neonates and infants ranging from 3 to 210 days of age at three nasopharyngeal temperature (NPT) ranges during cardiopulmonary bypass. Pressure-flow velocity relationships were studied during normothermic (NPT = 36-37 degrees C), moderate hypothermic (NPT = 23-25 degrees C), and profound hypothermic (NPT = 14-20 degrees C) CPB. A transcranial Doppler monitor was used to obtain CBFV, which was measured in the M1 segment of the middle cerebral artery. The CBFV was used as an index of cerebral perfusion. Anterior fontanel pressure (AFP) was subtracted from mean arterial pressure (MAP) to calculate CPP in mm Hg. Nasopharyngeal temperature, PaCO2, and hematocrit were controlled during the study period. Arterial blood gases were analyzed at 37 degrees C, uncorrected for body temperature (alpha-stat acid-base management). The CBFV measurements were made over a range of CPP from 6 to 90 mm Hg. Using nonlinear regression analysis, we showed that cerebral pressure-flow velocity autoregulation was present during normothermic CPB (r2 = 0.68). Autoregulation became pressure-passive, using linear regression analysis, during moderate hypothermic CPB (r2 = 0.33) and profound hypothermic CPB (r2 = 0.69). Cerebral blood-flow velocity was not detectable at a mean (+/- SD) CPP of 9 (+/- 2) mm Hg induced by the low-flow CBP state but became apparent when CPP was increased to 13 (+/- 1) mm Hg (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemofiltration during cardiopulmonary bypass.

Several factors combine to facilitate the evolution towards heart and multi-organ failure following cardiac surgery. Some of these factors are related to pure cardiac aspects like the existence of a preoperative heart disease, the use of aortic cross clamping or performance of cardiotomy. Cardiopulmonary bypass (CPB) also plays an important role in the occurrence of postoperative organ dysfunctions by two principal means: firstly by inducing a profound hemodilution, which impairs oxygen transport through tissues. This phenomenon is pointed out in the postoperative period by the existence of increased transpulmonary O2 gradients, extravascular lung water volume and subsequent impairments of O2 transport. Secondly CPB is deleterious by triggering an important inflammatory reaction. This reaction is largely related to the ratio of the circuit area to the patient's body surface area and is therefore maximal in children. It has been widely demonstrated that the very early paths of this reaction imply several humoral factors including kinins, coagulation factor-XII and complement fragments. The activation of these factors is self-amplified and triggers both expression and release of numerous mediators by endothelial cells and leukocytes. Finally, these mediators are responsible for the well described "post-bypass syndrome" which is, from a clinical viewpoint, very close to hyperkinetic septic shocks. Several methods have been proposed to reduce the deleterious effects of both cardiac surgery and CPB. The older one is hypothermia that considerably reduces the triggering of the inflammatory mediators network. Heparin-coated circuits may also reduce this reaction to some extent. Hemofiltration has been introduced in the 90's in CPB management. Because of its very high tolerance in patients with compromised circulatory status this technique was already used in the postoperative period to treat patients with acute renal failure. Initially hemofiltration was intended to correct the accumulation of extravascular water during or immediately following the surgical procedure. Nevertheless several of its "side-effects" appeared to be useful like reduction of postoperative blood loss and immediate hemodynamics improvement. Several studies attempted to point out the mechanism of action of hemofiltration and although removal of inflammatory mediator occurs, there is currently no proofs that this removal is the actual mechanism by which this technique acts. At the early beginning of the use of its utilization hemofiltration during cardiac surgery aimed either to concentrate blood at the end of the procedure or to rapidly restore a normal fluid and electrolytes balance. Today some new implementations of this technique are proposed either to reduce the triggering of the inflammatory reaction to CPB or to reduce the immediate postoperative drug support.     

Coagulation tests during cardiopulmonary bypass correlate with blood loss in children undergoing cardiac surgery.

OBJECTIVES: To examine whether coagulation tests, sampled before and during cardiopulmonary bypass (CPB), are related to blood loss and blood product transfusion requirements, and to determine what test value(s) provide the best sensitivity and specificity for prediction of excessive hemorrhage. DESIGN: Prospective. SETTING: University-affiliated, pediatric medical center. PARTICIPANTS: Four hundred ninety-four children. INTERVENTIONS: Coagulation tests. MEASUREMENTS AND MAIN RESULTS: Demographic, coagulation test, blood loss, and transfusion data were noted in consecutive children undergoing cardiac surgery. Laboratory tests included hematocrit (Hct), prothrombin time, partial thromboplastin time (PTT), platelet count, fibrinogen concentration, and thromboelastography. Stepwise linear regression analysis indicated that platelet count during CPB was the variable most significantly associated with intraoperative blood loss (in milliliters per kilogram) and 12-hour chest tube output (in milliliters per kilogram). Other independent variables associated with blood loss were thromboelastography maximum amplitude (MA) during CPB, preoperative PTT, preoperative Hct, and preoperative thromboelastography angle and shear modulus values. Thromboelastography MA during CPB was the only variable associated with total products transfused (in milliliters per kilogram). Of all tests studied, platelet count during CPB (< or = 108,000/microL) provided the maximum sensitivity (83%) and specificity (58%) for prediction of excessive blood loss (receiver operating characteristic analysis). Blood loss was inversely related to patient age; neonates received the most donor units (median, 8 units; range, 6 to 10 units). CONCLUSIONS: During cardiac surgery, coagulation tests (including thromboelastography) drawn pre-CPB and during CPB are useful to identify children at risk for excessive bleeding. Platelet count during CPB was the variable most significantly associated with blood loss.     

Effects of chlorpromazine as a systemic vasodilator during cardiopulmonary bypass in neonates

OBJECTIVES: Vasodilator use during cardiopulmonary bypass is important in pediatric cardiac surgery, but the full range of their effects on hemodynamics remains to be clarified. We studied the effects of chlorpromazine, a potent alpha-blocking agent, in neonates. METHODS: Subjects were 60 neonates undergoing arterial switch operations for complete transposition of the great arteries with an intact ventricular septum. Of these, 37 received 2.1 to 6.5 mg/kg of chlorpromazine during cardiopulmonary bypass (CPZ group) and 23 received no vasodilator (control group). We then compared hemodynamic parameters between groups during and early after surgery. RESULTS: The systemic vascular resistance index and mean arterial pressure during cardiopulmonary bypass were significantly lower in the CPZ group (p < 0.05), but systolic pressure 15 minutes after cessation of cardiopulmonary bypass did not differ between groups. The rise in peripheral temperature during rewarming after hypothermia was significantly higher and the acid-base status 40 minutes after cardiopulmonary bypass less acidotic in the CPZ group. Urine output during cardiopulmonary bypass was higher in the CPZ group. CONCLUSIONS: Chlorpromazine effectively counteracts systemic vasoconstriction induced by cardiopulmonary bypass without serious side effects in neonatal cardiac surgery.     

Coagulation and fibrinolysis system in pediatric cardiopulmonary bypass

Coagulation and fibrinolysis system was evaluated during and after pediatric cardiopulmonary bypass (CPB. Twenty-two atrial septal defect (ASD) patients were surgically repaired under CPB and aortic cross-clamp through right thoracotomy. Drainage was established by gravity, CPB flow was kept 2.4 l/min/m2 and ACT was controlled over 400 seconds. HCT, PLT, fibrinogen, AT-III, D-dimer, thrombin-antithrombin complex (TAT), alpha2 plasmin inhibitor-plasmin complex (PIC), and plasminogen activator inhibitor (PAI-1) were measured at 6 points [after induction of anesthesia, 10 minutes after initiating CPB, end of CPB, on the entrance of intensive care unit (ICU), postoperative day (POD) 1, and at outpatient division]. Both fibrinogen and AT-III showed low values during CPB (121.9 +/- 22.0 mg/dl, 57.6 +/- 10.6%). D-dimer increased at 1 week postoperatively in all patients (5.57 +/- 3.45 microg/ml). There were significantly positive correlations between CPB duration and TAT value at the end of CPB (r = 0.88, p < 0.01), on the entrance of ICU (r = 0.71, p < 0.01). There was also a positive correlation between CPB duration and PIC value on the entrance of ICU (r = 0.53, p < 0.01). Five patients showed high PAI-1 value on the entrance of ICU, which remained high in 2 of them on POD 1. The outcomes from the current study suggest that there is a potential of coagulation-dominant disseminated intravascular coagulation (DIC) during pediatric CPB even in ASD patients who do not need long CPB. Longer CPB and severe hemodilution might become risk factors.     

Coagulation tests predict bleeding after cardiopulmonary bypass

To determine the accuracy of coagulation profile laboratory tests, thromboelastography, and Sonoclot (SCT) values for predicting microvascular bleeding after cardiopulmonary bypass (CPB). A prospective, blinded trial. A large academic medical center. Eighty-two adult patients undergoing elective cardiac surgery. Ten minutes after CPB, thromboelastography, SCT, and coagulation profile tests (bleeding time, prothrombin time, activated partial thromboplastin time, fibrinogen, fibrin split products, platelet count, mean platelet volume, and platelet hematocrit) were determined from a whole blood sample taken from an existing arterial catheter. Patients were subjectively defined as “bleeders” or “non-bleeders” by blinded clinical observers. Preoperative baseline tests were also obtained.

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Thirty of the 82 patients (36.6%) were characterized as bleeders. Coagulation profile tests had the best correlation with intraoperative and postoperative blood loss. The specificity, sensitivity, and negative and positive predictive values were determined by receiver operating characteristic analysis, and the test values that differentiated normal from abnormal (bleeding) patients were determined. The coagulation profile laboratory tests had the greatest maximal sensitivity and specificity for predicting bleeding. These predictive values were outside the normal range for these laboratory tests. The thromboelastography values that produced maximal sensitivity and specificity were in the normal range for that test. Contrary to previous studies, coagulation profile tests had the greatest sensitivity and specificity to differentiate patients with excessive bleeding (abnormal) from those without excessive bleeding (normal) after CPB. Therefore, these tests should be used to guide transfusion therapy in patients who have excessive bleeding after CPB.     

Gut mucosal perfusion in neonates undergoing cardiopulmonary bypass

We studied gut mucosal perfusion in 24 neonates requiring cardiopulmonary bypass (CPB). Group A patients (n = 12) had obstruction to their aorta such that gut perfusion before operation was dependent on flow through a ductus arteriosus (DA). Group B neonates were of similar age and size and required a similar duration of CPB, but did not have a DA. An orogastric tonometer allowed intermittent calculations of gastric intramucosal pH (pHi), and rectal mucosal perfusion ("flux") was monitored using laser Doppler flowmetry. Measurements of arterial base deficit, and lactate and pyruvate concentrations were made intermittently. Before CPB, mean femoral arterial pressure (MAP) and base deficit in group A were not significantly different from those in group B. However, mean flux before CPB was significantly lower and the lactate/pyruvate (L/P) ratio was significantly higher in group A compared with group B. Mean pHi was below normal (< 7.26) throughout the operative period in group A, although it remained normal (> 7.33) in group B. After corrective surgery, both during warm CPB and after CPB, we found no significant difference in MAP, L/P ratio or base deficit between the groups, but both flux and pHi were significantly lower in group A compared with group B. We conclude that neonates requiring aortic arch surgery may be at particular risk of gut mucosal hypoxia both before and after operation.      

新生儿体外循环术后低体温影响因素分析

目的了解新生儿体外循环术后低体温发生现况,分析其影响因素,为针对性干预提供参考。方法对204例于体外循环下行先天性心脏畸形矫治术的新生儿,采用自制新生儿体外循环术中数据登记表收集其一般资料和手术相关资料共15项,进行单因素和多因素分析。结果 40.2%发生术后低体温;单因素分析显示,不同体质量、术前体温、止血关胸时间及是否急诊手术新生儿术后低体温发生率差异有统计学意义(P0.05,P0.01);多因素分析显示,低体质量、术前体温低于35.5℃及非急诊手术是新生儿术后低体温的独立危险因素(P0.05,P0.01)。结论新生儿体外循环术后低体温发生率较高,应采取针对性措施防范,尤其应重视低体质量、术前体温低及非急诊手术新生儿的防范,以保障手术安全。     

Miniaturized cardiopulmonary bypass system in neonates and small infants

Cardiopulmonary bypass (CPB) in children is associated with a capillary leak due to inflammatory response, which results in an increase in total body water. This study was designed to reveal that our miniaturized CPB system reduced the peri-operative systemic inflammatory response in small infants. In our institution, the priming volume has been reduced from 500 ml to 140 ml currently. Eighty consecutive patients weighing <5 kg were retrospectively reviewed. The postoperative peak C-reactive protein (CRP), body weight gain (%BWG), and the duration of postoperative mechanical ventilation (MVT) data were collected for each patient. Stepwise multiple logistic regression analyses were used to investigate which of the factors most affected the peri-operative inflammatory responses. A priming volume (coefficient: 0.060, P=0.01), most affected the postoperative peak CRP (mg/dl). A combination of priming volume (coefficient: 0.015, P=0.006), and bypass time (coefficient: 0.013, P=0.028), most affected %BWG (%). A combination of priming volume (coefficient: 0.05, P=0.001) and age (coefficient: -0.02, P=0.001) most affected the MVT (days). The miniaturized circuits reduced the peri-operative inflammatory response, resulting in reduced postoperative systemic edema, and postoperative mechanical ventilation time.     

库存红细胞清洗在新生儿及小婴儿体外循环手术中的应用

目的 对比体外循环(CPB)心脏手术中接受洗涤及未洗涤的库存红细胞(PRBC)对血清钾离子浓度(K+)及乳酸浓度(LAC)的影响.方法 选取复杂先天性心脏病(先心病)行CPB心脏手术的新生儿及小婴儿为研究对象,排除术前血乳酸大于3.0mmol/L的病婴.对照组(15例)接受未洗涤的PRBC进行CPB预充及术中添加,试验组(15例)接受用血液回收机(Medtronic Autolog)洗涤过的PRBC.在CPB前、CPB 3、15min、CPB复温、停止CPB前、术毕、术后4、24h比较血K+及LAC浓度.结果 洗涤PRBC显著降低供血中K+浓度[从(19.3±0.9)mmol/L降至(1.1±0.3)mmol/L,p<0.001]及IAC浓度[从>15mmol/L降至(7.8±1.2)mmol/L,P<0.001].对照组预充液的K+及ILAC浓度显著高于试验组[K+(9.0±0.5)rranol/L对(2.6±0.1)mmol/L,P<0.001;LAC浓度(9.5±0.5)mmol/L对(4.7±1.1)nrml/L,P<0.001].CPB 3min、CPB复温时对照组血清K+浓度显著高于试验组[CPB 3 min(5.6±0.9)mmol/L对(3.5±0.4)mmol/L,P<0.01;CPB复温时(4.8±0.7)mmol/L对(3.7±0.6)mmol/L,P<0.01];其余时点对照组K+浓度高于试验组,差异无统计学意义.CPB 3、15 min、CPB复温、停止CPB前、术毕、术后4 h对照组IAC浓度高于试验组,但差异无统计学意义.结论 洗涤PRBC降低血清钾及乳酸负荷,可预防cPB中高血钾.在新生儿及小婴儿复杂先心病CPB手术中应考虑应用清洗PRBC.     

库存红细胞清洗在新生儿及小婴儿体外循环手术中的应用

Objective Priming blood in cardiopulmonary circuit is necessary for neonates and small infants. However, high concentration of potassium and lactate in pecked red blood cells transfused during cardiopulmonary bypass may have detrimental effects on meonstea and infants undergoing cardiac surgery. This study is to cornice the effects of trasfusing washed end unwashed peeked red blood cells for cardiopulmonary circuit on serum potassium and lactate concentrations preoperatively. Methods 30 neonates and small infants with complex congenitai heart disease undergoing open heart surgery were divided into 2 groups randomly. Unwashed group (n = 15) received unwashed pecked red blood cells and washed group (n=15) received packed red blood cells washed in a cell saver (Medtronic Autolog). Potasium and lactate concertrations were compared before, during and after bypass. Resuils Wash-packed red blood cells reduced donor blood [K+] from (19.3±0.9)mmd/L to (1.1 +0.3) mmol/L, and lactate from 15 mmo/L to (7.8±1.2) mmol/L (P<0.001). The [K+]in the prime solution was significantly higher [(9.0±0.5) mmol/L vs. (2.6±0.1) mmol/L, P<0.001] in umwashed group than that of washed group, so did the lactate [(9.5±2.6) mmol/L vs. (4.7±1.1) mmol/L, P相似文献   

库存红细胞清洗在新生儿及小婴儿体外循环手术中的应用

Objective Priming blood in cardiopulmonary circuit is necessary for neonates and small infants. However, high concentration of potassium and lactate in pecked red blood cells transfused during cardiopulmonary bypass may have detrimental effects on meonstea and infants undergoing cardiac surgery. This study is to cornice the effects of trasfusing washed end unwashed peeked red blood cells for cardiopulmonary circuit on serum potassium and lactate concentrations preoperatively. Methods 30 neonates and small infants with complex congenitai heart disease undergoing open heart surgery were divided into 2 groups randomly. Unwashed group (n = 15) received unwashed pecked red blood cells and washed group (n=15) received packed red blood cells washed in a cell saver (Medtronic Autolog). Potasium and lactate concertrations were compared before, during and after bypass. Resuils Wash-packed red blood cells reduced donor blood [K+] from (19.3±0.9)mmd/L to (1.1 +0.3) mmol/L, and lactate from 15 mmo/L to (7.8±1.2) mmol/L (P<0.001). The [K+]in the prime solution was significantly higher [(9.0±0.5) mmol/L vs. (2.6±0.1) mmol/L, P<0.001] in umwashed group than that of washed group, so did the lactate [(9.5±2.6) mmol/L vs. (4.7±1.1) mmol/L, P相似文献   

库存红细胞清洗在新生儿及小婴儿体外循环手术中的应用

Objective Priming blood in cardiopulmonary circuit is necessary for neonates and small infants. However, high concentration of potassium and lactate in pecked red blood cells transfused during cardiopulmonary bypass may have detrimental effects on meonstea and infants undergoing cardiac surgery. This study is to cornice the effects of trasfusing washed end unwashed peeked red blood cells for cardiopulmonary circuit on serum potassium and lactate concentrations preoperatively. Methods 30 neonates and small infants with complex congenitai heart disease undergoing open heart surgery were divided into 2 groups randomly. Unwashed group (n = 15) received unwashed pecked red blood cells and washed group (n=15) received packed red blood cells washed in a cell saver (Medtronic Autolog). Potasium and lactate concertrations were compared before, during and after bypass. Resuils Wash-packed red blood cells reduced donor blood [K+] from (19.3±0.9)mmd/L to (1.1 +0.3) mmol/L, and lactate from 15 mmo/L to (7.8±1.2) mmol/L (P<0.001). The [K+]in the prime solution was significantly higher [(9.0±0.5) mmol/L vs. (2.6±0.1) mmol/L, P<0.001] in umwashed group than that of washed group, so did the lactate [(9.5±2.6) mmol/L vs. (4.7±1.1) mmol/L, P相似文献