Priming Fluid Research Articles

Prospective randomized study of albumin and dextran 40 as priming fluid for cardiopulmonary bypass

Prospective randomized study of albumin and dextran 40 as priming fluid for cardiopulmonary bypass

Differential Effect of Oncotic Pressure on Cerebral and Extracerebral Water Content during Cardiopulmonary Bypass in Rabbits

To study the effect of oncotic pressure on brain water content during cardiopulmonary bypass (CPB), 14 anesthetized New Zealand White rabbits underwent 60 min of nonpulsatile CPB at normothermia. Animals were grouped according to the composition of the circuit priming fluid. Group 1 animals (n = 7) received a priming fluid (6.5% hydroxyethyl starch in 0.72 N NaCl; 323 +/- 13 mOsm/kg [mean +/- SD]) that maintained normal colloid oncotic pressure (COP) during CPB (19.0 +/- 1.5 mmHg). Group 2 animals (n = 7) received a priming fluid (0.9 N NaCl; 324 +/- 23 mOsm/kg) that led to a hypooncotic state (COP = 6.2 +/- 1.2 mmHg). Blood chemistries and hemodynamics were recorded every 15 min during CPB. Animals were given additional priming fluid and sodium bicarbonate during CPB to maintain a circuit flow of 85 ml.kg-1.min-1 and arterial pH greater than 7.35. There were no significant differences between groups 1 and 2 with respect to temperature, central venous pressure, mean arterial pressure, PaO2, PaCO2, plasma sodium concentration, or osmolality at any time during CPB, although osmolality increased in both groups. After 60 min of bypass, animals were killed and organ water contents were determined by wet/dry weight ratios. A separate group of nine similarly prepared and anesthetized animals that did not undergo cannulation or CPB also underwent measurement of plasma chemistries and tissue water contents and served as nonbypass controls (group 3). Brain and kidney water contents were unaffected by oncotic pressure, whereas duodenum and skeletal muscle had significantly greater water content (P = 0.003 and P = 0.008, respectively) after hypooncotic CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

The metabolic consequences of a “washed” cardiopulmonary bypass pump-priming fluid in children undergoing cardiac operations

The substrate load of the pump-priming fluid, especially glucose and lactate, has a major influence on the metabolic response of children during cardiac operations and may be detrimental neurologically. It is possible to cleanse the priming fluid of these excess substrates by ultrafiltration followed by the addition of a balanced electrolyte solution. We have used this technique in the bypass management of nine children over 1 year of age and weighing less than 18 kg who were studied from induction of anesthesia to 6 hours postoperatively. Frequent blood samples were taken for measurement of electrolytes, intermediary metabolites, and stress-related hormones. Throughout the study period electrolyte concentrations were maintained within the physiologic range and changes in blood glucose and lactate were minimized compared with those of matched historical controls from previous studies. During the period of cardiopulmonary bypass mean serum glucose concentrations varied between 4.4 and 7.7 mmol/L and peaked at 10.7 mmol/L just before skin closure. The mean serum lactate concentration did not exceed 2.3 mmol/L during the period studied. Thus ultrafiltration of the priming fluid and replacement with a balanced electrolyte solution results in the delivery to the patient of a reasonably physiologic substrate load, which is reflected in improved control of mean plasma intermediary metabolite concentrations. The method may form the basis of further clinical studies to determine specific aspects of the metabolic stress response in children.

Glucose metabolism and insulin activity during cardiac surgery

Disorders of glucose metabolism were investigated in 177 patients undergoing cardiac surgery. In group I patients, the cardiopulmonary bypass (CPB) priming fluid contained glucose. Patients in group II received neither glucose nor insulin during the operation. Group III received insulin-glucose therapy OGT) during the operation (insulin, 1 U/kg/h, glucose, 0.5 g/kg/h). At the onset of CPB in group I, hyperglycemia was produced by the glucose load and by a relative reduction in insulin secretion. In group 11, the start of the operation was accompanied by a rise in the titer of insulin antibodies. IGT resulted in normalization of the blood glucose level after CPB and stability of the insulin antibody titer during the investigation. The indices of myocardial contractility in group III were better than those of the “glucose free” group II before and after CPB. In group II, indices of β-cell function were moderately depressed 16 to 18 hours after the operation. Insulin and c-peptide level measurements demonstrated insulin production in group III on the first postoperative day. The results demonstrate that IGT has some potential benefit for glucose metabolism and myocardial function during cardiac surgery.

Effects of priming fluids and oxygenators on arterial pressure and vascular resistance during cardio-pulmonary bypass

Effects of priming fluids and oxygenators on arterial pressure and vascular resistance during cardio-pulmonary bypass

Cardiopulmonary bypass technique in sheep

During the past two years at the University of Modena, 72 sheep underwent cardiopulmonary bypass (CPB) for various open-heart surgical procedures. An effective protocol for anaesthesia and CPB was developed in these animals. Routine barbiturate induction and maintenance anaesthesia with isofluorane and a pressure-regulated ventilator have minimized anaesthetic problems. The type of priming fluid used was the major factor in overcoming the problems associated with haemodilution effects, clotting insufficiency and postperfusion lung syndrome. Pump flows of 60ml.kg -1 bodyweight.min-1 seem to give adequate circulatory support during heart-lung bypass. A technical report and the pharmacological support protocols used successfully in 66 of the 72 animals during a two-year period are presented.

開心術における赤血球濃厚液単独使用の有用性に関する検討 新鮮血使用例との比較

We have tried to save the blood in open-heart surgery, then concentrated the diluted blood remained in the reservoir after cardiopulmonary bypass (CPB), and transfused it to the patients through venous line. Also we have primed extracorporeal circuit with concentrated red blood cells. In this study, we compare the results of this method with it produced through transfusion and the priming of fresh whole blood and fresh frozen plasma, and investigate the effectiveness and safety in the usage of concentrated red blood cells as the priming fluid. (Material and Method) From January, 1984 to December, 1987, 84 adult patients underwent coronary artery bypass surgery. We classified them into two groups, depending on their priming fluid for extracorporeal circuit, fresh whole blood or concentrated red blood cells. In group I consisted of 41 patients, fresh whole blood was used for the priming and in group II, consisted of 43 patients, in which concentrated red blood cells were applied and the blood components remained in the reservoir after weaning from CPB were concentrated and returned to patients. In these two groups, we compare the hemodynamic functions and the hematorogical data and also evaluate the safety through the usage of concentrated red blood cells in open-heart surgery. (Results) The components and average amount of blood used in group I were 11.6±5.5 units of fresh whole blood and 8.2±5.9 units of fresh frozen plasma. In group II, they were 6.1±3.0 units of concentrated red blood cells and almost no fresh whole blood or fresh frozen plasma were required. The diluted volume of 1, 315±320ml in the CPB reservoir was concentrated to 620±275ml of blood components and transfused. The values of hemoglobin and hematocrit were significantly higher in group I than these in group II, but there were no significant differences in cardiac index, pulmonary capillary wedge pressure and stroke work index among hemodynamic functions. The incidence of post-transfusion hepatitis was 3/41(7.3%) in group I, while zero in group II. (Conclusion) Concentrated red blood cells could be applied safely as the priming fluid for CPB in open-heart-surgery, and are clearly effective in prevention of post-transfusion hepatitis. These results indicate that this method has a big advantage.

Calcium, magnesium and phosphate during and after hypothermic cardiopulmonary bypass without temperature correction of acid base status.

The plasma concentration variations of calcium, magnesium and phosphate were studied in ten patients during and after hypothermic cardiopulmonary bypass (CPB) without temperature correction of acid base status. During the study, pH remained stable, but all the other studied components varied significantly (P less than 0.001). At the start of CPB, the mean ionized calcium concentration increased 25%, and magnesium and phosphate decreased 29% and 40%, respectively, from their control values. At the end of blood cooling, ionized calcium was still 11% above its initial value, magnesium 50% above, and phosphate 39% below. Before weaning from CPB, ionized calcium remained 10% above its initial level, magnesium 41% above, and phosphate 26% below. After CPB, the different divalent ions returned to their initial levels within 1 h for ionized calcium, 6 h for phosphate and 9 h for magnesium. One day post-CPB, ionized calcium was at its start level, magnesium 13% lower, and phosphate 36% higher. During cardiac surgery, the acid base regulation without temperature correction (so-called "alpha stat mode") avoided the appearance of carbon dioxide acidosis. There were widespread disturbances of the divalent ions concentrations, due principally to the different fluids used during CPB, pump priming fluids and cardioplegic solution.

Presence of circulating endotoxins during cardiac operations

Ten patients having coronary artery bypass grafting were intraoperatively and postoperatively analyzed for endotoxins with the Limulus amoebocyte lysate test. A new highly sensitive rocket immunoelectrophoretic assay for reading the reactions of endotoxins with Limulus amoebocyte lysate was used. Preoperatively, all blood samples from the patients had negative Limulus amoebocyte lysate tests, negative blood cultures, normal total white cell counts, and were clinically without signs of infection. Intraoperatively, a substantial amount of endotoxins were found in samples from the extracorporeal circuit, the pulmonary artery, and the cardiac suction lines, which persisted during the cardiopulmonary bypass. The endotoxin content decreased significantly (p less than 0.05) 6 hours after cardiopulmonary bypass and further decreased within the seventh postoperative day (p less than 0.01). A positive Limulus amoebocyte lysate test was also found in some of the fluids administered during the operation, that is, the cardioplegic fluids, the priming fluids for the extracorporeal circuit, the blood transfusions, and the ice for local cooling. Postoperatively, all patients had rectal temperatures below 38.5 degrees C, but no correlation was found between the magnitude of endotoxin content and the degree of fever. Only one of the patients had positive blood cultures. Despite the measured endotoxin content, no intraoperative or postoperative complications were found.

Analysis of microembolic particles originating in extracorporeal circuits

Silicone tubing is utilised increasingly in extracorporeal circulation (ECC), particularly for prolonged bypass in cases of left ventricular failure following open heart surgery. We compared the spectrum of particle formation in the EC circuit, due to roller pump damage, resulting from wear of silicone tubing with that of polyvinyl chloride (PVC) tubing. The EC circuit was primed with plasmalyte solution for pump runs of up to 24 hours. Samples of the perfusate were taken from either system at prefixed times. Number and size of the particles were determined by means of a Coulter counter, while their chemical composition was analysed by X-ray dispersion (EDXA). The tubing was examined by scanning electron microscopy. When using PVC tubing, the amount of particles of all sizes rose above acceptable standards shortly after activating the roller pump. Following this early upsurge, the number of particles continued to increase for the remainder of the pump run, albeit at a more moderate rate. The silicone tubing continuously generated a marked quantity of particular matter at a steadily increasing rate. Electron microscopic examination of the silicone tubing revealed multiple particles emanating from the inner surface of the tube. The results suggest that filtration of the initial priming fluid may be advisable before connecting the patient to an EC circuit using PVC tubing. The multitude of particles liberated by the silicone tubing implies that its usage in ECC should be curtailed. Utilisation of noncrushing head pumps is recommended in ECC.

EXTRACORPOREAL CIRCUIT SEQUESTRATION OF FENTANYL AND ALFENTANIL

Fentanyl or alfentanil, in doses approximating to those used in clinical practice, was added to the priming fluid of an extracorporeal circuit before the institution of cardiopulmonary bypass (CPB). The concentrations of both drugs in the priming fluid were measured over a 20-min period. The concentration of fentanyl decreased at neutral or high pH values, suggesting drug adsorption to the circuit. The concentration of alfentanil was unaffected. The administration of fentanyl to the priming fluid may produce lower anaesthetic concentrations than anticipated.

Neutrophil function and cardiopulmonary bypass in humans. The effects of glucose and non-glucose containing bypass pump priming fluids

Defective polymorphonuclear neutrophil function during cardiopulmonary bypass (CPB) has been implicated as a cause of postoperative infection following open-heart surgery. Neutrophil function is known to be impaired in poorly controlled diabetics with elevations of blood glucose concentrations of the order which occur frequently during CPB when glucose containing priming fluids are used. Neutrophil function, as measured by bactericidal assay, and neutrophil and whole blood luminol dependent chemiluminescence, was studied in two groups of 1 2 patients undergoing coronary artery bypass graft surgery. Patients received either a glucose or non-glucose containing bypass pump-priming fluid. Postoperatively neutrophil luminol-dependent chemiluminescence was significantly increased in both groups (glucose prime groups p < 0.01, non-glucose prime group p < 0.01). Whole blood chemiluminescence was increased significantly intra and postoperatively in the glucose prime group ( p < 0.02, p < 0.02 respectively) but the increase was not significant in the non-glucose prime group. Bactericidal activity remained unchanged during and after surgery in both groups (mean bactericidal index intraoperatively 96.4 glucose group, 96.2 non-glucose group; postoperatively 99.7 glucose group, 99.7 non-glucose group). These data suggest that glucose containing bypass priming fluids do not modulate significantly the function of circulating neutrophils after CPB. Neutrophil function was not decreased after surgery, and other factors may be responsible for the reported higher incidence of bacterial infection after CPB.

Glucose-insulin interactions during cardiopulmonary bypass: Hypothermia versus normothermia

Since hypothermia is commonly used to lower local and general metabolism during cardiopulmonary bypass, we attempted to identify its specific effects on glucose-insulin interactions. A group of nondiabetic patients undergoing hypothermic (28 degrees C) cardiopulmonary bypass with ischemic (cold) cardiac arrest was compared to a similar group operated on under normothermic conditions with potassium cardioplegia. In the absence of exogenous dextrose administration, hypothermia blocked insulin secretion for the duration of the operation. It also inhibited insulin secretion in response to an exogenous dextrose load (e.g., the priming fluid of the cardiopulmonary bypass circuit) or a glucagon injection, but this inhibition was lifted by rewarming. Blood glucose levels, which during normothermia were mildly elevated even in the absence of dextrose administration, remained normal during the hypothermic phase of cardiopulmonary bypass. By the end of the rewarming period, however, blood glucose levels had reached the same level as observed under normothermic bypass, a fact suggesting that the cold inhibition of hepatic glucose production had been only temporary. Cold inhibition of hepatic glucose production also explains why glucose clearance after a sudden dextrose load was initially faster at low body temperature than at normal temperature. Glucose-clamp studies indicated that insulin resistance was initiated by anesthesia and surgical trauma, and further accentuated by cardiopulmonary bypass, in association with elevated levels of hormones indicative of surgical stress. Regardless of body temperature changes, the assimilation of glucose by nondiabetic subjects during and immediately after bypass called for the infusion of large doses of insulin. A comparison with diabetic subjects showed that insulin-dependent patients (type I diabetes) required no more insulin during cardiopulmonary bypass than normal subjects, whereas patients with type II diabetes exhibited a marked insulin resistance during the operation and in the immediate postoperative period.

Chalk in the prime.

After observations of cloudiness in the perfusion circuit at open intracardiac operations, laboratory experiments showed a precipitate in a Hartmann's solution (compound sodium lactate solution, Ringer-lactate) and sodium bicarbonate based priming fluid used for cardiopulmonary bypass. The precipitate was found to consist of calcium carbonate crystals. The crystals were not dissolved by adding plasma proteins, nor were they sufficiently cleared from the extracorporeal circuit by a 40 microns filter in the arterial line. The crystals may embolise in microvascular beds and thus be a cause of postoperative morbidity. The practice of adding sodium bicarbonate to the pump prime may be unnecessary.

Metabolic consequences of different crystalloid pump priming fluids in small children undergoing open heart surgery (OHS)

Metabolic consequences of different crystalloid pump priming fluids in small children undergoing open heart surgery (OHS)

The effect on intermediary metabolism of open-heart surgery with deep hypothermia and circulatory arrest in infants of less than 10 kilograms body weight. A preliminary study

The effects of hypothermic open-heart surgery with circulatory arrest upon intermediary metabolism and endocrine function in small children are still poorly understood. This report presents data obtained in a preliminary study in which seven children of <10 Kg body weight were investigated during and after such procedures. Frequent blood samples were taken from one day preoperatively to seven days postoperatively for estimation of hormone concentrations (insulin, growth hormone, glucagon, cortisol), and intermediary metabolites (glucose, lactate, pyruvate, alanine, glycerol, and 3- hydroxybutyrate).Marked hyperglycaemia (34·8 ±3·3 mmol/L) was observed during cardiopulmonary bypass probably as a result of the glucose content of the pump prime. Moderate hyperglycaemia persisted for at least seven days postoperatively. A significant increase in lactate concentrations (p < 0·02) was observed during circulatory arrest and peak concentrations of 6·77 +0.87 mmol/L were measured at the end of the operation. Very high blood lactate concentrations were observed at the end of cardiopulmonary bypass in two patients who subsequently died. Peak insulin concentrations (20·7 ± 5·2 mU/L) were lower than those (30-40 mU/L) reported in adults undergoing similar procedures. Glucagon concentrations were significantly elevated during bypass ( p<0·05) to approximately twice the levels reported in adults. Unlike the other hormones, growth hormone concentrations revealed remarkably uniform change, similar to those reported in 'high responding' adults with peak values of 124 ± 26 mU/L, observed during cardiopulmonary bypass. Cortisol concentrations showed no significant changes throughout the study.Thus, the response of small infants to these procedures differed both qualitatively and quantitatively from that reported in adults. The results suggest that the nature of the prime fluid may be of major importance in the metabolic consequences of such surgery and that glucose and lactate may be better avoided in the pump prime.

The effects of four different crystalloid bypass pump-priming fluids upon the metabolic response to cardiac operation

The crystalloid solutions used to prime cardiopulmonary bypass pumps frequently contain metabolically active substrates. However, there is a lack of controlled studies to investigate the metabolic response to cardiac operations using different pump primes. We have carried out a prospective, randomized study of 24 patients divided into four groups, each group receiving a different crystalloid prime. The primes contained glucose, lactate, glucose and lactate, or neither glucose nor lactate. Using identical anesthetic, surgical, and perfusion techniques, we estimated the metabolic response to cardiac operation in all patients by frequent blood sampling for measurement of hormone (insulin, glucagon, cortisol, and growth hormone) and metabolite concentrations (glucose, lactate, pyruvate, glycerol, alanine, and 3-hydroxybutyrate) from the day before operation to the seventh postoperative day. The results demonstrated that, after 4 hours postoperatively, the endocrine and metabolic response to cardiac operation was unaffected by the nature of the priming fluid. However, major endocrine and metabolic changes occurred before that time, which were related directly to the glucose and lactate contents of the prime. Very high concentrations of both glucose and lactate were observed at the end of bypass if they were induced in the prime. Given the known dangers of hyperglycemia in cerebral ischemia and the potential gluconeogenic effects of infused lactate, we suggest that glucose-free and lactate-free primes be employed in the extracorporeal circuit.

CONTINUOUS MONITORING OF BLOOD GLUCOSE CONCENTRATION DURING OPEN-HEART SURGERY

Continuous monitoring of blood glucose concentration was compared with frequent intermittent sampling in 12 non-diabetic adult patients undergoing open-heart surgery with cardiopulmonary by-pass using priming fluids free of glucose. Continuous monitoring revealed several changes which were not detected on intermittent sampling. Blood glucose concentration decreased by 2 mmol litre-1 +/- 0.5 (SEM) (P less than 0.01) immediately on the institution of CPB, and increased during the succeeding minutes. Rewarming from hypothermic by-pass was associated with a 3 (+/- 0.5)-mmol litre-1 increase in blood glucose concentration (P less than 0.01). Commencement of infusions of sympathomimetic agents resulted in a similar increase.

A prospective randomized study of hydroxyethyl starch, albumin, and lactated Ringer’s solution as priming fluid for cardiopulmonary bypass

The ideal priming fluid for cardiopulmonary bypass is not known. We designed a study to determine whether there are important differences in the clinical effects of hydroxyethyl starch versus albumin when used in priming fluid, and in the clinical effects of colloid versus crystalloid priming fluid. We prospectively randomized 83 adult patients undergoing coronary artery bypass or valve replacement. All patients were managed by standardized protocol, and they received one of three priming fluids for bypass: hydroxyethyl starch (HES), 26 patients; albumin (ALB), 28 patients, and lactated Ringer's solution (LRS), 29 patients. The groups were stratified by body weight and type of operation. We measured 41 variables relating to operative time factors, fluid balance, bleeding, and organ function (renal, cardiac, and pulmonary) at several time intervals. The LRS group had a significantly lower colloid osmotic pressure than the other two groups, and the HES group had a substantially higher blood viscosity. Although the prothrombin time was significantly lower in the LRS group (p less than 0.05), the differences were very small and not clinically important. The platelet count in the HES group was significantly lower than in the other two groups immediately after bypass, but it was not different by the time the patients left the operating room. There were no differences among the groups in chest tube drainage, blood bank usage, or fluid balance. Postoperatively, the pulmonary shunt fraction was significantly greater in the LRS group. Body weight increased more in the LRS than in the HES and ALB groups (p = 0.01). No adverse reaction to the prime solutions was noted. The differences between the HES and ALB groups--prothrombin time, platelet count, and blood viscosity--had no apparent clinical effects; thus, the two may be considered clinically equivalent. The greater somatic and pulmonary fluid accumulation in the LRS group suggests that colloid is preferable to crystalloid in priming fluid.

The importance of colloid osmotic pressure during open heart surgery in infants.

Fifty-five infants with transposition of the great arteries and with total anomalous pulmonary venous return underwent intracardiac repair under combined surface/perfusion hypothermia and total circulatory arrest in 1975 to 1983. Although cardiopulmonary bypass (CPB) time is limited when hypothermic circulatory arrest is employed, fluid balance derangement is one of the major postoperative complications. Fluid balance at the end of CPB averaged +299.5 ml (+63.4 ml/kg) when hemodilution with lactated Ringer's was utilized (Group A). Since colloid osmotic pressure (COP) plays an important role in regulating fluid balance, colloid hemodilution prime (whole blood and plasma) was employed in the last 3 years (Group B). COP and total protein concentration during CPB with colloid prime were maintained at around 19 mmHg and 5 g/100 ml, respectively. In Group B, fluid balance at the end of CPB averaged +81.1 ml (+16.3 ml/kg) and was significantly less than in Group A (p less than 0.01). The ICU stay period for survivors in Group B (average 10.9 days) was reduced to half the period in Group A (average 20.6 days) (p less than 0.05). The mortality rate in Group A was 42%, whereas 23% in Group B. It was concluded that well-maintained COP levels during CPB with colloid hemodilution prime reduced fluid accumulation in the body and made patient care easier following open heart surgery in infants.