Sondel P M, Tripp M E, Ganick D J, Levy J M, Shahidi N T
Pediatrics. 1981 May;67(5):667-70.
Patients with chronic hypoxia develop a physiologically appropriate "secondary" polycythemia that improves oxygen carrying capacity. Supplemental iron is often required to maintain this. In severe cases when hematocrit levels approach 70%, iron is withheld in order to avoid dangerously high hematocrit levels and the risks of vascular sludging due to "hyperviscosity." Some patients even require reduction of viscosity by exchange of their polycythemic blood for plasma when symptoms develop. Iron deficiency with microcytic polycythemia can then develop. Management of such patients is unclear. Continued blood withdrawal will worsen the iron deficiency; iron supplementation will increase the hematocrit level and the risks of hyperviscosity. The combination of frequent phlebotomy with oral iron therapy should improve iron stores while safely maintaining a stable hematocrit level in patients with microcytic polycythemia. This combination should also have multiple beneficial effects on tissue oxygen delivery and utilization. This approach has been discussed and used for a patient with microcytic polycythemia due to Eisenmenger syndrome. While on therapy the patient's clinical symptoms decreased, and his serum iron level, hematologic indices, and treadmill tolerance tests all improved.
慢性缺氧患者会出现生理上适当的“继发性”红细胞增多症，从而提高携氧能力。通常需要补充铁来维持这一状态。在血细胞比容水平接近70%的严重病例中，会停用铁剂以避免血细胞比容水平过高以及因“高黏滞度”导致血管内血液淤滞的风险。当症状出现时，一些患者甚至需要通过用其红细胞增多的血液置换血浆来降低血液黏滞度。继而可能会出现缺铁伴小细胞性红细胞增多症。对此类患者的管理尚不清楚。持续放血会使缺铁情况恶化；补充铁剂会提高血细胞比容水平以及增加高黏滞度的风险。对于小细胞性红细胞增多症患者，频繁放血与口服铁剂治疗相结合应能改善铁储备，同时安全地维持稳定的血细胞比容水平。这种联合治疗还应对组织氧输送和利用产生多种有益影响。这种方法已被讨论并应用于一名因艾森曼格综合征导致小细胞性红细胞增多症的患者。在治疗期间，该患者的临床症状减轻，其血清铁水平、血液学指标以及跑步机耐力测试均有所改善。
