Renal blood flow velocity in acute renal failure following cardiopulmonary bypass surgery

Two lysosomal storage diseases, aspartylglucosaminuria and mannosidosis, are associated with highly elevated serum dolichol concentrations. To elucidate possible mechanisms leading to elevated serum dolichols, we studied the effects of Triton WR 1339 (known to increase serum cholesterol) and orotic acid (known to decrease serum cholesterol) on blood and biliary dolichol and beta-hexosaminidase levels in rats. In Triton WR 1339-treated rats, serum dolichol was markedly increased compared with saline-treated controls 1 (400 +/- 70 ng/mL, n = 7 v 85 +/- 11 ng/mL, n = 8, P < .001), 4 (789 +/- 70 ng/mL, n = 10 v 110 +/- 10 ng/mL, n = 7, P < .0001), and 8 (549 +/- 43 ng/mL, n = 8 v 87 +/- 8 ng/mL, n = 7, P < .001) days after administration of the drug. By contrast, serum dolichol was decreased (64 +/- 5 ng/mL, n = 8 v 119 +/- 7 ng/mL, n = 8, P < .0001) after a 7-day orotic acid feeding compared with controls. Serum beta-hexosaminidase was unaffected by both treatments. Orotic acid also increased biliary dolichol (280 +/- 47 ng/100 g body weight [BW]/h, n = 7 v 83 +/- 15 ng/100 g BW/h, n = 7, P < .01) and beta-hexosaminidase (21 +/- 3 mU/100 g BW/h, n = 7 v 8.3 +/- 2 mU/100 g BW/h, n = 9, P < .01) excretion compared with controls. Thus, both Triton WR 1339 and orotic acid have an effect on dolichol metabolism, and it is conceivable--based on our results--that serum dolichol concentrations are regulated, at least in part, by a mechanism similar to that for serum cholesterol levels.     

Epinephrine-induced lactic acidosis following cardiopulmonary bypass

OBJECTIVE: To determine if lactic acidosis occurring after cardiopulmonary bypass could be attributed to the metabolic or other effects of epinephrine administration. DESIGN: Prospective, randomized study. SETTING: Postsurgical cardiothoracic intensive therapy unit. PATIENTS: Thirty-six adult patients, without acidosis, requiring vasoconstrictors for the management of hypotension after cardiopulmonary bypass. INTERVENTIONS: Randomized administration of either epinephrine or norepinephrine by infusion. MEASUREMENTS AND MAIN RESULTS: Hemodynamic and metabolic data were collected before commencement of vasoconstrictor therapy (time 0) and then 1 hr (time 1), 6 to 10 hrs (time 2), and 22 to 30 hrs (time 3) later. Six of the 19 patients who received epinephrine developed lactic acidosis. None of the 17 patients receiving norepinephrine developed lactic acidosis. In the epinephrine group, but not in the norepinephrine group, lactate concentration increased significantly at times 1 and 2 (p = .01), while pH and base excess decreased (p < or = .01). Blood glucose concentration was higher in the epinephrine group at time 2 (p = .02), while the cardiac index (p < .03) and the mixed venous Po2 (p = .04) were higher at time 1. compared with the norepinephrine group, the patients receiving epinephrine had higher femoral venous lactate concentrations (p = .03), increased lower limb blood flow (p = .05), and increased femoral venous oxygen saturations (p = .04). CONCLUSIONS: The use of epinephrine after cardiopulmonary bypass precipitates the development of lactic acidosis in some patients. This phenomenon is presumably a beta-mediated effect, and is associated with an increase in whole-body and lower limb blood flow and a decrease in whole-body and transfemoral oxygen extraction. The phenomenon does not appear to be related to reduced tissue perfusion and does not have the poor outlook of lactic acidosis associated with shock.     

Unusual dyskinesia complicating cardiopulmonary bypass surgery

Four infants developed dyskinesia after cardiopulmonary bypass surgery three to four days postoperatively. The dyskinesia was choreoathetotic, and involved mainly the mouth, tongue and face. It was absent during sleep. Three of these infants improved over periods of several weeks, but one infant remained dyskinetic one year postoperatively. Neuro-imaging studies and EEGs were of little value in determining the cause of the dyskinesia. The factors responsible for the involuntary movements and for their severity remain unexplained.     

The acute phase response to cardiopulmonary bypass in children

We recently obtained the brain of a rare lemuroid primate, Cheirogaleus medius. The brain was not perfused before death, but rather fixed by immersion shortly thereafter. In both flat-mounted and transversely sectioned tissue, we were able to clearly demonstrate periodic zones of high cytochrome oxidase (CO) activity in the primary visual cortex, resembling the so-called 'blobs' described in many other primate species. Our results contrast with a previous report indicating that blobs are absent in Cheirogaleus medius and provide support for the view that blobs are an evolutionary specialization of primate visual cortex that evolved only once, early in primate history. In other aspects of architectonic organization, area V1 of this Cheirogaleus individual closely resembles that of other strepsirhine primates, such as Galago. We were able to identify additional divisions of cortex in this individual, including the middle temporal visual area (MT), auditory cortex, and the primary somatosensory area (S1 or area 3b). These observations indicate that valuable neuroanatomical information can, in favorable cases, be obtained from rare mammalian species that die of natural causes in captivity or which must be euthanized, even though the animals have not been perfused.     

Management of postoperative heparin rebound following cardiopulmonary bypass

Postoperative heparin rebound was investigated in 50 adult patients undergoing cardiopulmonary bypass with the use of the Hepcon heparin analyzer. Prior to bypass each patient received 2 mg/kg of heparin. During bypass, the activated clotting time (ACT) was utilized to assess the need for additional heparin to maintain the value between 300 and 400 seconds. The average amount of heparin given was 160 mg. Once cardiopulmonary bypass was terminated the Hepcon unit was employed to determine the actual amount of active circulating heparin and to calculate the dose of protamine sulfate. The average amount of protamine administered intraoperatively was 200 mg. The overall mean ratio of protamine-to-heparin was 1.25 : 1. Once hemostasis was achieved, no circulating heparin was measured with the Hepcon unit, and the ACT value had returned to its baseline, the incisions were closed and the patients were transferred to the intensive care unit. One hour later a blood sample was obtained and analyzed by the Hepcon unit for any heparin rebound. We found that 26 patients (52%) had circulating heparin and required an additional dose of protamine, averaging 70 mg. Drainage from the thoracotomy tubes averaged 400 cc in the first 24 hours, and a mean of 2 units of packed cells was infused. Three patients (6%) did not require any blood transfusions. The use of the Hepcon unit has produced a safe and expedient method of analyzing and neutralizing active circulating heparin in patients following cardiopulmonary bypass. It is a useful adjunct in blood conservation because it reduces excessive postoperative blood loss associated with heparin rebound.     

The application of phenoxybenzamine in open heart surgery using cardiopulmonary bypass

Renovascular hypertension in two sisters, aged 22 and 20, respectively, has been described. Renal artery stenoses were observed unilaterally in the elder patient and bilaterally in the younger one. In both patients, the functional significance of unilateral stenosis of the renal artery was documented by the renal vein renin ratio between the affected side and the contralateral or less affected side. High blood pressure and elevated plasma renin activity have been normalized with a unilateral revascularization in the elder patient, and with the treatment of propranolol in the younger one. The histological examination of the stenotic renal artery in the elder patient showed a finding comparable to the perimedial fibroplasia in Harrison and McCormack's classification of idiopathic fibromuscular stenosis.     

The platelet in cardiopulmonary bypass

Platelets are the smallest of the blood cells and are known to be activated during cardiopulmonary bypass. They play a role in many associated complications. Both quantitative and qualitative platelet defects have been demonstrated, resulting in microvascular hemorrhage and thromboembolism. As their interactions with endothelium and other blood cells are unraveled, the important contribution they make toward the systemic inflammatory response to operation seen in cardiopulmonary bypass is increasingly evident. In this review, we consider platelet activation during cardiopulmonary bypass, the resultant clinical effects, and potential approaches to therapy and prevention.     

Assessing postoperative cognitive change after cardiopulmonary bypass surgery.

Cognitive decline after cardiopulmonary bypass (CPB) surgery has been a concern since the advent of CPB procedures. A primary focus of many studies on this topic has been to quantify the incidence of post-CPB cognitive impairment. However, studies that have used traditional parametric statistics have generally failed to confirm that long-lasting (–- I month) cognitive declines occur reliably after CPB surgery. For the present study, the authors used a split-plot analysis of variance model that revealed preoperative memory impairments in the CPB patients and new postoperative impairments of attention. The authors discuss the assumptions of, and problems associated with, analysis methods that are often used to quantify the incidence of cognitive impairment following CPB surgery. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emergency percutaneous cardiopulmonary bypass support for acute myocardial infarction

We assessed the efficacy of emergency percutaneous cardiopulmonary bypass support (PCPS) in the treatment of patients with acute myocardial infarction complicated by cardiogenic shock. Emergency PCPS was instituted in 21 consecutive patients beginning in 1991. After the stabilization of the hemodynamics, coronary reperfusion was performed by means of coronary artery bypass grafting or percutaneous transluminal coronary angioplasty. Of the seven patients with acute myocardial infarction involving either the left main or two-vessel territories, five survived more than 1 month, but only one patient remained alive and well after 20 months. The main cause of death for this group was low output syndrome. Four of 12 patients with acute left main trunkal occlusion in the catheter laboratory survived and showed a preserved cardiac function (mean followup 28.5 months). The main cause of death for this group was brain damage. Two patients with single-vessel territory acute myocardial infarction underwent PCPS to treat refractory ventricular fibrillation. Both patients were still alive and well at a 12-month followup. Percutaneous cardiopulmonary bypass support successfully stabilized the hemodynamics, allowing time to perform revascularization for all three groups of patients with life-threatening acute myocardial infarction. Recanalization was nevertheless unable to salvage the damaged myocardium in cases of prolonged ischemic time.     

Induction of aquaporin-1 mRNA following cardiopulmonary bypass and reperfusion

BACKGROUND: Cardiopulmonary bypass (CPB) and hypothermic circulatory arrest (HCA) are important components of congenital cardiac surgery. Ischemia/reperfusion injury and inflammatory cascade activation result in endothelial damage and vascular leak which are clinically manifested as pulmonary edema and low cardiac output postoperatively. Newborns are particularly susceptible. Subtraction cloning is a useful method of isolating induced genes and can be applied to CPB/HCA. MATERIALS AND METHODS: We used a newborn lamb model replicating infant CPB with HCA to obtain tissues during various periods of reperfusion. We utilized subtraction cloning to identify mRNA induced in lung following CPB/HCA and reperfusion. Ribonuclease protection was used to quantify mRNA levels. RESULTS: We isolated a cDNA encoding ovine aquaporin-1 in a subtracted cDNA screen comparing control lung with lung exposed to CPB/HCA and reperfusion. Aquaporin-1 mRNA levels increased 3-fold in lung (p = .006) exposed to CPB/HCA and 6 hr of reperfusion. No induction was observed immediately following bypass or after 3 hr of reperfusion. We found no significant induction of aquaporin-1 mRNA following bypass, arrest, and reperfusion in other tissues surveyed, including ventricle, atrium, skeletal muscle, kidney, brain, and liver. CONCLUSIONS: Our finding that aquaporin-1 mRNA is reproducibly induced in lung following CPB/HCA with 6 hr of reperfusion suggests an important role for the water channel in the setting of pulmonary edema. Induction of Aquaporin-1 is late compared with other inflammatory mediators (ICAM-1, E-selectin, IL-8). Further studies are needed to determine if aquaporin-1 contributes to the disease process or if it is part of the recovery phase.     

Effect of ultrafiltration during cardiopulmonary bypass for pediatric cardiac surgery

The effect of ultrafiltration during cardiopulmonary bypass (CPB) was evaluated for correcting ventricular septal defects with associated pulmonary hypertension in patients less than 18 months old. Interleukin (IL)-6 and IL-8 concentrations in the blood, ultrafiltrate, and urine were measured. The blood IL-6 concentration increased to 128.4+/-20.2 pg/ml by the end of surgery, which is lower than the concentration seen in adult patients (273.1+/-48.2 pg/ml, p < 0.02). The blood IL-8 concentration was not significantly different than that of adults. The total amounts of excreted IL-6 in the ultrafiltrate and urine during CPB were 11.5+/-0.32 pg/kg and 0.32+/-0.07 pg/kg, respectively (p < 0.05). The total amounts of excreted IL-8 in the ultrafiltrate and urine were 4.64+/-0.69 pg/kg and 1.92+/-0.56 pg/kg, respectively (p < 0.05). No differences were seen in these values for excretion between children and adults. We conclude that ultrafiltration during CPB in pediatric patients is more effective in removing proinflammatory cytokines than in adults and more effective than renal filtration alone.     

Elimination of cardiopulmonary bypass: a prime goal in reoperative coronary artery bypass surgery

OBJECTIVE: The purpose of this study was to evaluate morbidity and mortality in reoperative coronary artery bypass surgery using the New York State database. METHODS: Patients undergoing reoperative coronary artery bypass between January-1995 and December 1996 were included. Patients were operated using cardiopulmonary bypass (CPB group, n = 184) or without cardiopulmonary bypass (non-CPB group, n = 105) by surgeon preference. Groups were compared for preoperative risk factors, postoperative mortality and major complications. RESULTS: Crude mortality was lower in the non-CPB group, despite a higher expected mortality, resulting in a risk-adjusted mortality of 1.3% versus 2.7% for the CPB group (NS). Of non-CPB patients, 91.4% were without complications, while only 72.1% of CPB patients (P < 0.0001) were complication-free. Major complications were significantly reduced in non-CPB patients compared to CPB patients: stroke 0% versus 3.8% (P < 0.04), cardiovascular complications 4.8% versus 15.8% (P < 0.005), other major complications 1.9% versus 10.4% (P < 0.007). Postoperative IABP support was needed in 1.9% of the non-CPB group patients and in 14.2% of the CPB group (P < 0.0007). CONCLUSIONS: The main object of reoperative CABG is to relieve symptoms, since the survival benefit of the procedure has not been demonstrated. Performance of reoperative coronary artery bypass surgery without cardiopulmonary bypass significantly reduces morbidity. We conclude that cardiopulmonary bypass should be avoided whenever possible in reoperative coronary bypass surgery.     

Cardiac surgery using cardiopulmonary bypass in a patient with sickle-cell trait

The sickle-cell gene is most concentrated in West Central Africa, the northeast corner of Saudi Arabia and East Central India. Sickle cell trait is the heterozygous condition for Hb S gene. Thirty to fifty per cent of their hemoglobin is Hb S and the remainder is Hb A. The sickle-cell crisis is induced by hypoxia, hypercarbia, acidosis, low flow condition, and hypothermia, which leads to vasoocclusion. A 39-year-old black man from Burkina Faso located in West Africa with left ventricular rupture was admitted for operation using cardiopulmonary bypass (CPB). He had been diagnosed as sickle-cell trait. The Hb S concentration was 36.2 per cent before operation with hemoglobin electrophoresis. During CPB, the minimum blood temperature was 31 degrees C and an aortic cross-clamp was not done. Total CPB time was 1 hour 31 minutes. Use of vasodilator and hyperventilation was effective. No neurological sequelae were observed.     

Necrotizing enterocolitis after open heart surgery employing hypothermia and cardiopulmonary bypass

Three patients, 1-11 months of age, who underwent open heart surgery with cardiopulmonary bypass and profound hypothermia, developed necrotizing enterocolitis postoperatively leading to death. Pneumatosis intestinalis and portal vein gas were demonstrated radiographically. Necrotizing enterocolitis has not been previously reported as a complication of cardiopulmonary bypass and profound hypothermia.     

Post-traumatic ventricular septal defect following coronary bypass surgery

A 60-year-old patient underwent triple coronary artery bypass grafting following an inferoseptal myocardial infarction and early onset of exertional angina. Four years later he was involved in a car accident during which he sustained an abdominal and thoracic trauma. Approximately 1 month after discharge, a ventricular septal defect was diagnosed by two-dimensional Doppler echocardiography with patency of all grafts at coronary angiography. Closure of the septal defect was successfully accomplished through a right atrial approach. Rupture of the ventricular septum following blunt chest trauma in a patient with previous myocardial revascularization has not been previously reported.     

A Tourette-like syndrome following cardiopulmonary bypass and hypothermia: MRI volumetric measurements

OBJECTIVES: To review the outcome of men with Stage I nonseminomatous germ cell tumors managed with a policy of active surveillance following orchiectomy. METHODS: The clinical records of all men with Stage I nonseminomatous germ cell tumors seen at Royal Prince Alfred Hospital, Australia between 1982 and 1995 were reviewed. Data were obtained concerning the histologic type of tumor, levels of serum tumor markers, relapse and subsequent treatment, and survival. RESULTS: Seventy-seven patients were entered into the active surveillance protocol between 1982 and 1995. With a minimum follow-up of 2 years, 27 (35%) have relapsed, with a median time to relapse of 5 months. Two late relapses occurred at 37 and 57 months after diagnosis. Relapses occurred most commonly in the retroperitoneal lymph nodes, with the lungs the second most common site. Following treatment with chemotherapy and surgery, all patients achieved complete remission, with 1 patient subsequently relapsing and ultimately dying of progressive tumor. One other patient died of acute myeloid leukemia, thought to be secondary to chemotherapy. Overall, 75 patients (97%) remain alive and free of disease. CONCLUSIONS: Active surveillance is a safe and effective approach to the management of Stage I nonseminomatous germ cell tumors. Although most relapses occur within the first 2 years, late relapses may occur.