| 翻訳と辞書 |
| Anemia of prematurity ： ウィキペディア英語版 |
Anemia of prematurity
Anemia of prematurity refers to a form of anemia affecting preterm infants with decreased hematocrit.
==Pathophysiology==
Preterm infants are often anemic and typically experience heavy blood losses from frequent laboratory testing in the first few weeks of life. Although their anemia is multifactorial, repeated blood sampling and reduced erythropoiesis with extremely low serum levels of erythropoietin (EPO) are major determining factors.〔Adams, M., Benitz, W., Geaghan, S., Kumar, R., Madan, A., & Widness, J. (2005). Reduction in red blood cell transfusions using a bedside analyzer in extremely low birth weight infants. Journal of Perinatology 25, 21-25. Retrieved November 16, 2007, from EbscoHost Research Databases.〕〔Astruc, D., Donato, L., Haddad, J., Matis, J., & Messer, J. (1993). Early treatment of premature infants with recombinant human erythropoietin. Pediatrics 92(4), 519-523. Retrieved December 9, 2007, from EbscoHost Research Databases〕〔Connolly, N., Cress, G., Johnson, K., Kulhavy, J., Lin, J., Strauss, R., Widness, J., & Zimmerman, M. (2000). Phlebotomy overdraw in the neonatal intensive care nursery. Pediatrics 106(2), 19. Retrieved November 16, 2007, from EbscoHost Research Databases.〕 Blood sampling done for laboratory testing can easily remove enough blood to produce anemia. Obladen, Sachsenweger and Stahnke (1987) studied 60 very low birth weight infants during the first 28 days of life. Infants were divided into 3 groups, group 1 (no ventilator support, 24 ml/kg blood loss), group 2(minor ventilated support, 60 ml/kg blood loss), and group 3(ventilated support for respiratory distress syndrome, 67 ml/kg blood loss). Infants were checked for clinical symptoms and laboratory signs of anemia 24 hours before and after the blood transfusion. The study found that groups 2 and 3 who had significant amount of blood loss, showed poor weight gain, pallor and distended abdomen. These reactions are the most frequent symptoms of anemia.〔Obladen, M., Sachsenweger, M., & Stahnke, M. (1988). Blood sampling in very low birth weight infants receiving different levels of intensive care. Abstract retrieved November 27, 2007, from EbscoHost Research Databases.〕
During the first weeks of life, all infants experience a decline in circulating red blood cell (RBC) volume generally expressed as blood hemoglobin concentration (Hb).〔Strauss, R. (n.d.). Neonatal anemia: Pathophysiology and treatment. Transfusion Immunology and Medicine, 341-343. Retrieved December 10, 2007, from Google Scholar Research Databases.〕 As anemia develops, there is even more of a significant reduction in the concentration of hemoglobin.〔Boxwell G. (2000). Chapter 8 hematological problems: Anemia. Neonatal Intensive Care Nursing, 164-187. Retrieved December 12, 2007, from EbscoHost Research Databases.〕 Normally this stimulates a significant increased production of erythropoietin (EPO), but this response is diminished in premature infants. Dear, Gill, Newell, Richards and Schwarz (2005) conducted a study to show that there is a weak negative correlation between EPO and Hb. The researchers recruited 39 preterm infants from 10 days of age or as soon as they could manage without respiratory support. They estimated total EPO and Hb weekly and 2 days after a blood transfusion. The study found that when Hb>10, EPO mean was 20.6 and when Hb≤10, EPO mean was 26.8. As Hb goes down, EPO goes up.〔Dear, F., Gill, G., Newell, J., Richards, M., & Schwarz B. (2005). Effects of transfusion in anemia of prematurity. Pediatric Hematology and Oncology 22, 551-559. Retrieved December 9, 2007, from EbscoHost Research Databases.〕 While the reason for this decreased response is not fully understood, Strauss (n.d.) states that it results from both physiological factors (e.g., the rapid rate of growth and need for a commensurate increase in RBC mass to accompany the increase in blood volume) and, in sick premature infants, from phlebotomy blood losses. In premature infants this decline occurs earlier and more pronounced that it does in healthy term infants. Healthy term infants Hb rarely falls below 9 g/dL at an age of approximately 10–12 weeks, while in premature infants, even in those without complicating illnesses, the mean Hb falls to approximately 8g/dL in infants of 1.0-1.5 kg birth weight and to 7g/dL in infants <1.0 kg. Because this postnatal drop in hemoglobin level is universal and is well tolerated in term infants, it is commonly referred to as the “physiologic” anemia of infancy. However, in premature infants the decline in Hb may be associated with abnormal clinical signs severe enough to prompt transfusions.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Anemia of prematurity」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|