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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The successful early repair of congenital heart disease has placed the focus on the long-term outcome for surviving patients. This article reviews the neurologic risks of cardiopulmonary bypass, deep hypothermia, and circulatory arrest. Potential neurologic and developmental sequelae in both the immediate postoperative period and the long term are discussed, with a review of current, research-based literature.
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PMID:Neurologic and developmental outcomes following pediatric cardiac surgery. 753 8

The survival of infants with congenital heart disease has improved dramatically. However, the incidence of neurological injury in infants surviving cardiac surgery remains considerable. These neurological sequelae are attributable at least in part to hypoxia-ischemia/reperfusion, which inevitably accompanies infant heart surgery with deep hypothermia, cardiopulmonary bypass, and circulatory arrest. To begin to identify mechanisms of brain injury during infant cardiac surgery, we used near-infrared spectroscopy to study the relationship between cerebral intravascular (hemoglobin) and mitochondrial (cytochrome aa3) oxygenation in 63 infants (aged 1 day to 9 months) undergoing deep hypothermic repair of congenital heart defects, throughout the intraoperative period. Moreover, we assessed the effect of postnatal age on these changes. The cerebral concentration of oxidized cytochrome aa3 decreased from the onset of deep hypothermic cardiopulmonary bypass, despite apparent abundant intravascular oxygenation manifested by a simultaneous increase in the cerebral concentration of oxyhemoglobin. During this interval infants older than 2 weeks had a greater decrease in oxidized cytochrome aa3 than did infants 2 weeks old or younger. During deep hypothermic circulatory arrest, cerebral levels of oxidized cytochrome aa3 remained depressed while those of oxyhemoglobin declined. With reperfusion following circulatory arrest, the recovery of oxidized cytochrome aa3 was delayed, despite a rapid recovery of intravascular oxygenation (HbO2). After rewarming and 60 minutes of reperfusion, only 46% of infants recovered to the baseline level of cerebral oxidized cytochrome aa3. These findings demonstrate a paradoxical dissociation of changes in intravascular and mitochondrial oxygenation during hypothermic cardiopulmonary bypass; a pronounced decrease of mitochondrial oxygenation is established during induction of hypothermia and a delay in recovery of mitochondrial oxygenation occurs following circulatory arrest. These effects were more pronounced in infants older than 2 weeks than in younger infants. The data suggest potentially deleterious impairments of intrinsic mitochondrial function or of delivery of intravascular oxygen to the mitochondrion or both, effects previously undetected and apparently influenced by cerebral maturation.
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PMID:Cerebral oxygen supply and utilization during infant cardiac surgery. 771 85

Scoliosis surgery in the adolescent is prolonged, painful and haemorrhagic. There are neurological risks and surveillance of the medulla is necessary throughout surgery. An anterior (Dwyer, Zielke) or posterior (Harrington, Cotrel-Dubousset, Luque) approach to the spinal column cas used. Surgery using a posterior approach is the more haemorrhagic. The haemorrhage is increased by poor positioning of the patient, by the duration of surgery and by taking the bone graft. Constant care should be given to blood economy, using controlled hypotension, haemodilution and peroperative autotransfusion of lost blood (Cell-Saver). The anaesthetic should provide excellent analgesic effects and must be compatible with regain of consciousness during surgery and/or or the use of evoked potential techniques. Complications at that time are those of the circulation and those of neurological origin and linked with hypothermia. In the presence of haemorrhage, the maintenance of total blood volume is difficult when there is cardiopathy (myopathy). Neurological complications should be detected sufficiently early for them to be reversible (sensori-motor evoked potentials and/or "wake-up test"). Hypothermia is constant and requires the systematic use of a heated mattress, a heated humidifier and the heating of infusions. The postoperative complications are respiratory in origin and are especially associated with neuro-muscular disease (postoperative artificial ventilation). The per- and postoperative difficulties demonstrate the importance of the preoperative examination and of the preparation of the operation (respiratory preparation). Finally, staged autotransfusion should be used, when possible, and should be part of the techniques of blood economy in a true transfusion strategy.
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PMID:[Anesthetic problems and postoperative care in the surgery for scoliosis]. 781 11

Occasionally children undergoing cardiac surgery using cardiopulmonary bypass with deep hypothermia and cardiac arrest develop a postoperative syndrome of acute chorea. The authors report the neuropathological findings in two such children surgically treated for congenital heart disease. Examination of the brain showed neuronal loss, reactive astrocytosis and degeneration of myelinated fibers (without frank necrosis) in the globus pallidus, primarily the outer segment, with sparing of other regions commonly susceptible to hypoxic-ischemic necrosis. The localization and relative mildness of the brain damage suggest a susceptibility of the globus pallidus to injury in this setting and implicate disruption of pallidal pathways in the pathogenesis of post-cardiac surgery choreic syndrome.
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PMID:Selective injury of the globus pallidus in children with post-cardiac surgery choreic syndrome. 785 70

Many infants who require cardiac surgery have cyanotic heart disease. We assessed the relative tolerances to ischemia of hearts from immature normoxemic rabbits versus hearts from immature rabbits subjected to hypoxemia since birth. Normoxemic animals were raised from birth in an environment where the inspired fractional concentration of oxygen (FIO2) was 0.21; for the hypoxemic studies FIO2 was reduced to 0.09. Hearts (n = 6/group) from normoxemic and chronically hypoxemic rabbits at 7-12, 21-28, 35-44, and 51-56 days of age underwent aerobic "working" perfusion with Krebs bicarbonate buffer, and cardiac function was measured. Hearts were then arrested by a 3-min infusion with either cold (14 degrees C) Krebs buffer (hypothermia alone group) or St. Thomas' Hospital II solution (hypothermia plus cardioplegia group) before 6 h of hypothermic (14 degrees C) global ischemia. Hearts were reperfused, and postischemic creatine kinase leakage and recovery of function were measured. For hearts protected with hypothermia alone, recovery of aortic flow was better in hearts hypoxemic from birth compared with normoxemic controls at 7-12 days (78 +/- 7 vs. 60 +/- 6%, P < 0.05) and 21-28 days old (81 +/- 12 vs. 26 +/- 28%, P < 0.05). Protection with hypothermia plus cardioplegia was also better in hearts hypoxemic from birth compared with normoxemic controls at 7-12 days (74 +/- 8 vs. 63 +/- 10%, P < 0.05) and 21-28 days old (84 +/- 3 vs. 71 +/- 5%, P < 0.05). Protection with hypothermia alone and hypothermia plus cardioplegia was no different within chronically hypoxemic age groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tolerance of the developing heart to ischemia: impact of hypoxemia from birth. 790 Aug 70

Because many infants who require cardiac operation have cyanotic heart disease, we determined whether the existing calcium content of St. Thomas' II solution (1.2 mmol/L) is optimal to protect the immature rabbit heart hypoxemic from birth during subsequent ischemia. Modified hypothermic St. Thomas' II solutions (calcium content, 0 to 2.4 mmol/L) were compared with hypothermic Krebs bicarbonate buffer in protecting chronically hypoxemic (PaO2 = 34 +/- 11 mmHg, SaO2 = 63% +/- 3%) versus normoxemic (PaO2 = 76 +/- 11 mmHg, SaO2 = 92% +/- 3%) immature hearts (7 to 12 days old) during ischemia. Hearts (n = 6 per group) underwent aerobic 'working' perfusion with Krebs bicarbonate buffer and cardiac function was measured. The hearts were then arrested with a 3 minute infusion of either cold (14 degrees C) Krebs buffer (1.8 mmol calcium/L) as hypothermia alone or modified St. Thomas' II solution before 6 hours of hypothermic (14 degrees C) global ischemia. Hearts were reperfused and postischemic enzyme leakage and recovery of function were measured. A bell-shaped dose-response profile was observed for recovery of postischemic aortic flow but not for postischemic creatine kinase leakage, with improved protection occurring at lower calcium concentrations. Optimal myocardial protection occurred at a calcium content of 0.4 mmol/L, which was significantly better than with hypothermia alone or standard St. Thomas' II solution. We conclude that the existing calcium concentration of St. Thomas' II solution is responsible, in part, for its inadequate protection of immature myocardium hypoxemic from birth during ischemia.
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PMID:Calcium and cardioplegic protection of the ischemic immature heart: impact of hypoxemia from birth. 794 63

The development of open-heart surgery has been reviewed beginning with general body hypothermia and inflow stasis, then continuing with extracorporeal circulation by controlled cross-circulation. The successes with the latter technique stimulated rapid development of the simple disposable highly effective bubble oxygenator for extracorporeal circulation to permit correction of virtually all forms of congenital and acquired heart disease. For the few conditions not amenable to corrective procedures, heart replacement became a practical reality. The creation of chronic heart block in the early operations had a very deleterious effect upon survival until highly effective electrical pacing was developed.
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PMID:The Society Lecture. European Society for Cardiovascular Surgery Meeting, Montpellier, France, September 1992. The birth of open-heart surgery: then the golden years. 804 65

There is still controversy about the optimal method of venoarterial cardiopulmonary bypass (CPB) for correction of congenital heart disease in neonates and young infants. High rates of CPB-related morbidity and mortality are still reported. Since 1980, conventional CPB with double caval cannulation with right-angled cannulae has been used in the high majority of neonates at Marie-Lannelongue Hospital. The extracorporeal circuit was miniaturized to be primed with a volume as small as possible. Priming (500 ml) was done with packed red cells and fresh frozen plasma. CPB was conducted at 30% haematocrit and normal ranges of flow rate, arterial pressure, systemic vascular resistances and oxygen delivery. These normal physiological parameters were also maintained during hypothermia. During the last two years, 151 neonates below 15 days old who underwent open-heart surgery were reviewed. The overall hospital mortality was 7.24%. None of the survivors had postoperative complications related to CPB. All physiological and biological values remained within normal ranges during the postoperative course.
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PMID:Conventional cardiopulmonary bypass in neonates. A physiological approach--10 years of experience at Marie-Lannelongue Hospital. 816 67

In the child cardiocentre in Prague 5-Motol in 1977-1993 a total of 420 neonates with critical inborn heart disease were operated. Obstructive defects of the left heart were found in 178 children, obstructive defects of the right heart in 87, defects with a left-right shunt with pulmonary hypertension in 75, conotruncal malformations in 73 and various operations were made in 7 children. Complete repair of the defect was achieved in 281 neonates, incl. 104 where extracorporeal circulation was used. Palliative operations were made in 139 children. Early mortality during the entire period was 26%, whereby a decrease from 40% to 16% was recorded during the last three years. At present it is possible to repair permanently critical inborn heart disease in the majority of neonates. This is made possible in particular by early non-invasive diagnosis, treatment with prostaglandins E in duct-dependent critical heart disease, optimal time for and selection of most suitable surgery, microsurgical technique, miniaturization of extracorporeal circulation and the method of deep hypothermia.
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PMID:[Heart surgery in neonates (experience with surgery in 420 neonates)]. 818 69

In addition to primary circulatory disturbance, the presence of congenital heart disease may compromise the development of organ systems including the myocardium, the pulmonary vasculature and the central nervous system. Therefore, early elective repair of complex congenital heart defects is desirable. Today repair of complex congenital heart defects in the neonate can be achieved at low early and late mortality and morbidity with favorable long-term functional results. However, much remains to be learnt about the cellular and molecular effects of open heart surgery and hypothermia on the neonate.
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PMID:Reparative cardiac surgery in the very young. 827 82


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