Comparison of the effects of red cell separation and ultrafiltration on heparin concentration during pediatric cardiac surgery

To determine the effects of red cell separation and ultrafiltration on heparin concentration. Prospective study. University-affiliated, pediatric medical center. Thirty-one children undergoing cardiac surgery. Blood sampled for heparin concentration and coagulation tests. Thirteen infants underwent modified veno-venous ultrafiltration (UF) after cardiopulmonary bypass (CPB). In addition, residual blood in the CPB circuit was hemoconcentrated by UF and reinfused (UF group). Heparin concentration increased from 2.0 ± 0.6 to 2.5 ± 0.8 U/mL, following modified UF; while activated coagulation time (ACT) decreased from 701 ± 177 to 627 ± 107 seconds. Heparin concentration of CPB circuit residual increased from 1.9 ± 0.7 to 3.1 ± 1.0 U/mL.In 18 children (older than 1 year old), the residual blood in the CPB circuit was hemoconcentrated by cell separation (CS) and reinfused (CS group). Heparin concentration of CPB circuit residual decreased from 2.6 ± 0.6 to 0.3 ± 0.2 U/mL. After reinfusion, patient heparin concentration remained unchanged at <0.05 U/mL. Thrombin time increased from 28 ± 6 to 48 ± 29 seconds and did not correlate with H. The plasma concentration of heparin increased after veno-venous modified UF of the patient. Heparin concentration also increased after UF of residual CPB circuit blood. In contrast, circuit blood hemoconcentrated by CS contained minimal heparin, and, when infused, did not increase patient's heparin concentration. ACT and thrombin time did not correlate with heparin concentration.     

Predictors of blood loss after coronary artery bypass grafting

To assess the predictive value of variables possibly associated with blood loss after coronary artery bypass grafting (CABG). A prospective study. A university hospital. Eighty-nine patients scheduled for elective CABG. Blood samples were drawn before and after surgery. Chest tube drainage was measured hourly until removal of drains. Activation of coagulation and fibrinolysis, routine clotting tests, and expression of platelet surface antigens were analyzed using flow cytometry. A significant correlation was found among blood loss and activated partial thromboplastin time, fibrinogen, prothrombin fragment 1 + 2, D-dimers, platelet count, GPlb and P-selectin expression on platelets, use of internal thoracic artery, cross-clamp time, and thrombin-antithrombin III complex. In a multiple regression model, glycoprotein (GP) Ib expression on platelets, platelet count, use of internal thoracic artery, and D-dimers were significantly associated with blood loss. Logistic regression analysis showed that GPIb and D-dimers predicted an increased blood loss with a positive predictive value of 73% and a negative predictive value of 91%. Postoperative D-dimers and GPIb expression may be useful to exclude nonsurgical causes in bleeding patients after CABG.     

Pain management in cardiac surgery patients: Comparison between standard therapy and patient-controlled analgesia regimen

To compare standard nurse-based pain therapy with a patient-controlled analgesia (PCA) regimen. Prospective, randomized study. Single-institutional, clinical investigation in an urban, university-affiliated hospital. Sixty patients undergoing elective first-time cardiac surgery were included. In 30 patients, a standard analgesic regimen was used, and in 30 patients, a PCA regimen was used. The perioperative and postoperative management was similar for all patients. Degree of sedation, satisfaction, and pain (by visual analog scale [Vas]) was assessed within the first 3 postoperative days. Vital capacity (VC) and forced expiratory volume in 1 second (FEV₁) were measured using a portable spirometry system. Cortisol and troponin T (TnT) plasma levels were also measured. The expectation of pain was similar in both groups, and the postoperative pain score was significantly lower in the PCA than in the standard group throughout the study period. Significantly more piritramid was used in the PCA (total, 75.6 ± 33.4mg) than in the standard group (total, 20.1 ± 31.9 mg). VC and FEV₁ were significantly lower in the standard group compared with the PCA patients. Cortisol and TnT plasma levels were similar in both groups. Frequency of side effects were similar for both groups. Because of the beneficial effects with regard to degree of pain and satisfaction, pain management using PCA systems can be recommended for cardiac surgery patients. It appears to be superior to standard nurse-based pain therapy.     

Effect of aspirin in coronary artery bypass grafting

To evaluate the effect of aspirin (ASA) therapy on postoperative blood loss, transfusion requirements, reoperation for bleeding, duration of stay in the intensive care unit and in the hospital in a selected population undergoing a first coronary artery bypass grafting (CABG) surgery. Prospective observational study in consecutive patients during a 3-month period. A teaching cardiothoracic center. Two hundred forty consecutive patients undergoing elective coronary artery bypass grafting surgery for the first time. Two hundred forty consecutive patients admitted for a first CABG the day before surgery were visited. Patients with an abnormal routine coagulation screen or taking drugs that might have affected their coagulation mechanisms were prospectively excluded (n = 96). The date of the last dose of ASA was recorded in the 144 remaining patients, and data were acquired prospectively. Total mediastinal blood drainage, blood products usage, reopening, and duration of intensive care unit and hospital stay were recorded. Patients were grouped by days free of ASA. There were no significant differences detected between groups. In patients undergoing a first CABG and with no known factors affecting their coagulation, ASA therapy did not appear to increase blood loss, reopening for bleeding, or blood products usage requirements during the hospital stay. ASA therapy did not influence the duration of stay in intensive care or in the hospital.     

Thoracic epidural anesthesia does not affect functional recovery from myocardial stunning in sevoflurane-anesthetized dogs

A beneficial effect of thoracic epidural anesthesia (TEA) on recovery from myocardial stunning was previously shown in awake dogs. The aim of this study was to investigate the effects of TEA on recovery from myocardial stunning in sevoflurane-anesthetized dogs. Randomized animal study. Animal laboratory of a university hospital. Chronically instrumented mongrel dogs. Six dogs were chronically instrumented for measurement of hemodynamics and myocardial wall thickening fraction (WTF). The following experiments were performed on separate days in a crossover fashion: (1) 10 minutes of ischemia of the left anterior descending (LAD) coronary artery during sevoflurane anesthesia without TEA and (2) 10 minutes of ischemia during sevoflurane anesthesia with TEA. WTF was measured awake (baseline) and at predetermined time points until complete recovery of myocardial function occurred. Induction of anesthesia led to a decrease of WTF compared with baseline. Induction of ischemia led to a further decrease of WTF to negative values, which returned to positive values within the first minute of reperfusion. There were no differences between the two experimental conditions at any of the time points measured. In awake dogs, TEA improved the recovery from myocardial stunning compared with the control experiment. There was no difference between conscious dogs with TEA or sevoflurane-anesthetized dogs with or without TEA. TEA has no additional protective effect on the recovery of WTF during sevoflurane anesthesia.     

Effect of humeral head component size on hemiarthroplasty translations and rotations

Glenohumeral translation and rotation were measured in 6 grossly normal, fresh frozen shoulder preparations while a manual load was applied to the humerus. The same tests (maximum elevation, total rotation, anterior/posterior () translation, and inferior translation) were repeated for each shoulder through 8 series: 1 with the shoulder intact, 1 with the shoulder vented, and 6 with progressively larger humeral head components after hemiarthroplasty. There was an inverse linear relation between humeral head component size and all 4 outcome variables. Replacing the native head with a component of equal diameter reduced elevation 20%, rotation 40%, translation 50% and inferior translation 60% in the vented shoulder. Replacing the native head with a component of equal effective volume decreased elevation 8%, rotation 20%, translation 25%, and inferior translation 40% in the vented shoulder. Increasing humeral head component size decreased rotation, translation, and inferior translation by similar percentages and elevation somewhat less. Humeral head component size is better described in terms of volume than in terms of diameter or offset. J Shoulder Elbow Surg 1998;7:591-8.)     

Amrinone versus dopamine-nitroglycerin after reconstructive surgery for complete atrioventricular septal defect

To compare the effectiveness and safety of amrinone and a combination of dopamine and nitroglycerin in infants after reconstructive surgery for congenital heart disease. A prospective, randomized, double-blind study. Pediatric intensive care unit in a university hospital. Thirty-two infants with complete atrioventricular septal defect. Amrinone loading dose, 2 mg/kg, followed by a maintenance infusion, 7.5 μg/kg/min, was given to 17 infants before separation from cardiopulmonary bypass. The remaining 15 patients received a combination of dopamine, 5 μg/kg/min, and nitroglycerin, 1 μg/kg/min. The circulatory state of the patients was evaluated from 4 to 18 hours after cardiopulmonary bypass. The systemic blood flow index, calculated using the Fick principle, was higher in the amrinone group (2.5 ± 0.7 L/min/m²) compared with the dopamine-nitroglycerin group (2.0 ± 0.6 L/min/m², mean ± SD). The pulmonary blood flow index in the amrinone group was higher (2.9 ± 0.6 L/min/m²) than in the dopaminenitroglycerin group (2.2 ± 0.6 L/min/m²); no significant difference was noted in the mean pulmonary artery pressure. The oxygen extraction ratio was higher in the dopamine-nitroglycerin group (0.41 ± 0.07) compared with the amrinone group (0.34 ± 0.08). Despite lower platelet counts in the amrinone group, no hemorrhagic complications were seen in any patient. With this dosage regimen, amrinone provides a higher cardiac output, more favorable oxygen dynamics, and lower pulmonary vascular resistance than dopamine and nitroglycerin.     

The effect of three different doses of tranexamic acid on blood loss after cardiac surgery with mild systemic hypothermia (32°C)

Prophylactic administration of tranexamic acid (TA), an antifibrinolytic agent, decreases bleeding after cardiac surgery with systemic hypothermia (25°C to 29°C). Warmer systemic temperatures during cardiopulmonary bypass (CPB) may reduce bleeding and thus alter the requirement for TA. The effect of three different doses of TA on bleeding after cardiac surgery with mild systemic hypothermia (32°C) is evaluated. Double-blind, prospective, randomized study. University hospital. One hundred fifty adult patients undergoing aortocoronary bypass or valvular cardiac surgery. Patients received TA, 50 (n = 50), 100 (n = 50), or 150 (n = 50) mg/kg intravenously before CPB with mild systemic hypothermia. Blood loss through chest drains over 6, 12, and 24 hours after surgery and total hemoglobin loss were measured. Autotransfused blood, transfused banked blood and blood products, and coagulation profiles were measured. Analysis of variance on log-transformed data for blood loss and confidence intervals (Cis) of 0.95 were calculated and transformed to milliliters of blood. No patient was re-explored for bleeding. Blood loss at 6 hours was statistically greater in the 50-mg/kg group compared with the other two groups (p = 0.03; p = 0.02). Total hemoglobin loss was statistically greater in the 50-mg/kg group compared with the 150-mg/kg group (p = 0.04). There was no statistical difference in blood transfusion rate or coagulation profiles among the three groups. However, preoperative hemoglobin level was statistically lower in the 150-mg/kg group compared with the other two groups (p = 0.01). Of the three doses of TA studied, the most efficacious and cost-effective dose to reduce bleeding after cardiac surgery with mild hypothermic systemic perfusion is 100 mg/kg.     

The incidence of artery puncture with central venous cannulation using a modified technique for detection and prevention of arterial cannulation

Cannulation of the central circulation is essential for management of patients who require major surgery, and for patients who are critically ill. Arterial puncture is the most frequent complication associated with central venous cannulation, and is potentially fatal. Detection of arterial puncture can be problematic, especially in patients with cyanotic congenital heart disease. One thousand eleven consecutive cardiothoracic and vascular surgical patients who required central venous cannulation were studied using a new technique for detection of arterial puncture and prevention of arterial cannulation. This technique involves continuous pressure transduction of the steel introducer needle. Central venous cannulation was attempted in all patients. The sites of attempted catheterizations, number of arterial punctures and cannulations, and the number of successful catheterizations were noted. All patients were treated in accordance with standard anesthetic and surgical techniques in the institution. One thousand one hundred seventy-two central venous catheters were placed. The overall success rate was 99.6%. The incidence of arterial puncture was 9.3% for central venous cannulation attempts of the internal jugular, subclavian, and femoral veins. No arterial cannulation occurred, and none of the patients had significant complications. Congenital heart disease patients had a higher incidence of arterial puncture (14.1%) and a lower rate (96.8%) of successful cannulation. Pressure transduction of the steel needle is a useful technique for detecting arterial puncture and preventing arterial cannulation during attempts to achieve central venous cannulation.     

Nitroglycerin-induced hypoxemia does not produce myocardial ischemia

Nitroglycerin has been the drug of choice for relieving myocardial ischemia for more than a hundred years. Several studies have indicated that a significant reduction in arterial oxygen tension (PaO₂) occurs after the administration of sublingual nitroglycerin to patients with coronary artery disease breathing room air. Because available oxygen in arterial blood is reduced, it would be reasonable to assume that oxygen delivery to the myocardium would also be impaired. The purpose of this study was to investigate whether nitroglycerin-induced arterial desaturation results in compromised oxidative metabolism of myocardium assessed by coronary sinus lactate concentration and oxygen content in patients with coronary artery disease undergoing coronary artery bypass surgery. Ten randomly selected patients undergoing coronary bypass surgery. All studies were performed at Siyami Ersek Cardiovascular and Thoracic Surgery Center. A catheter was inserted into the radial artery to measure blood gases and arterial lactate concentration. After sternotomy, and aortic and venous cannula placement, a coronary sinus catheter was introduced into the coronary sinus to measure oxygen content and lactate concentration. Control coronary sinus and arterial blood samples were obtained before nitroglycerin infusion. Nitroglycerin was then given in a dose of 2 μg/kg/min for a period of 5 minutes. At the end of 5 minutes, second samples were obtained from the coronary sinus and arterial catheters. It was found that arterial and coronary sinus oxygen tension decreased significantly. Arterial lactate concentration did not change, coronary sinus lactate concentration decreased. Despite a substantial fall in arterial oxygen tension after administration of nitroglycerin, a significant reduction in coronary sinus lactate concentration occurred. Nitroglycerin-induced hypoxia does not compromise oxidative metabolism of myocardium as can be assessed by a concomitant decrease in coronary sinus lactate concentration.     

Uncemented total hip arthroplasty in patients 50 years of age or younger

The results of a consecutive series of uncemented total hip arthroplasties in patients 50 years or younger are reviewed. There were 41 total hip arthroplasties in 36 patients at an average follow-up period of 5.3 years. Average patient age was 42 years at the time of implantation. Preoperative Harris hip score (HHS) averaged ; the final HHS averaged 93. Radiographic evaluation revealed that the femoral stems were all solid, with no progressive subsidence, reactive lines, or osteolysis. Twenty of the hips (49%) demonstrated evidence of polyethylene wear. There was significant acetabular osteolysis in 12 of these 20 hips. Five of the acetabular cups were definitely loose; 1 was possibly loose. Three of the patients underwent revision surgery for acetabular loosening and/or osteolysis. It is concluded from this study that the femoral stem is excellent but that the original acetabular component and polyethylene locking mechanism are poor and made even worse with the use of a titanium femoral head.     

Delayed blind-pouch apposition,guide wire placement,and nonoperative establishment of luminal continuity in a child with long gap esophageal atresia

Delayed primary esophago-esophagostomy is the most physiologically attractive approach to establish luminal continuity in children with pure esophageal atresia. However, excessive tension on the mobilized esophageal ends can lead to anastomotic separation and severe leakage. To circumvent these complications, the blind pouches of a 2-month-old child were approximated unopened when, during the extrapleural thoracotomy, a conventional anastomosis was not feasible. A suture was passed through the tip of the 2 ends and made to exit through the mouth and the gastrostomy. After healing occurred, the suture was replaced under fluoroscopic control by a Seldinger-type wire. A vein dilator then was passed over the wire, establishing the continuity between the esophageal segments. Subsequent dilatations increased the anastomosis to the desired diameter. Leakage and an additional thoracotomy were avoided, and the hospital stay was shortened. The child, now 6 years old, is well and swallows normally.     

Allograft acceptance and rejection, mediated by a liver suppressor factor, LSF-1, purified from serum of liver transplanted rats

In certain rat strain combinations liver allografts are spontaneously accepted without immunosuppression and induce donor-specific tolerance to further skin and heart grafts in the recipient. Such an effect is also transferrable using serum from orthotopically liver transplanted rats (OLT serum). In the OLT serum of one such combination. DA (RT1^a) donor into PVG (RT1^c) recipient, a 40 kDa protein (liver suppressor factor, LSF-1) has been identified and shown to be immunosupressive in vitro. The aim of the present study is to investigate the immunological effect of LSF-1 and a polyclonal antibody (anti-LSF-1) against this molecule, in a rat heterotopic heart transplant (HHT) model and OLT model, respectively. Intramuscular injection of 300 μg of LSF-1, 1 h postoperatively, into a PVG recipient of either a DA or BN (RT1ⁿ) cardiac allograft caused significant prolongation of graft survival. Intravenous injection of polyclonal rabbit sera raised against an N-terminal peptide of LSF-1 (anti-LSF-1), within 1 h postoperatively, had variable effects on the survival of DA liver grafts in PVG recipients. In cases injection of between 1 and 2 ml of anti-LSF-1 resulted in death of the recipient. Histological examination of the liver showed severe rejection with lymphoid cell infiltration of the portal tract and sinusoids and extensive damage to the parenchyma. All control rats survived for more than 60 days without any signs of rejection. The anti-LSF-1 polyclonal antibody prevented the induction of tolerance in the normally tolerogenic model (DA into PVG). This, together with the in vivo results, suggests a role for LSF-1 in the induction of tolerance.     

Guide wire-assisted urethral dilatation for urethral strictures in pediatric urology

Purpose: The aim of this study was to report the results of 32 cases of dilatation of urethral stricture using a guide wire and sheath dilator technique supplemented by clean intermittent catheterization if further stabilization of the urethral stricture was felt warranted.Methods: The procedure involves insertion of a straight flexi-tip lubricated guide wire through the urethral stricture under cystoscopic guidance followed by insertion of a series of sheath dilators. Dilatation was followed by insertion of a Foley catheter, which was left in situ for 1 to 3 days. Patients underwent repeat cystoscopy to evaluate the urethra for recurrent stricture and those with a recalcitrant stricture were commenced on clean intermittent catheterization (CIC) to stabilize the narrowing.Results: Thirty-two patients were included. They have been followed up for up to 2 years after their last cystoscopy (mean, 16 months). Thirteen of 32 patients had more than 4 dilatations under anesthesia. Twelve patients had undergone CIC postoperatively. Complications included a urinary tract infection in 3 boys and bladder spasms in one. No false passage or sepsis occurred with this approach.Conclusions: Guide wire-assisted urethral dilatation helps avoid risks associated with blind dilatation techniques and appears to be a safe and simple alternative for management of urethral strictures in pediatric urology.