日本未熟児新生児学会雑誌　第24巻第2号　73～77頁（2012年）

日本未熟児新生児学会雑誌　24(2)：285-289；2012　

受付日：平成23．10．11

受理日：平成24．01．19

新生児血液型不適合溶血性黄疸におけるCOHbの検討

Analysis of COHb in Neonatal Hemolytic Jaundice

加古川市民病院機構加古川西市民病院　小児科

Department of Pediatrics, Kakogawa West City Hospital, Kakogawa City Hospital Foundation

森沢　猛・米谷昌彦・小寺孝幸・中尻智史・上村裕保・海老名俊亮・湊川　誠

Takeshi MORISAWA，Masahiko YONETANI，Takayuki KODERA，Tomoshi NAKAJIRI，Hiroyasu UEMURA，Syunsuke EBINA，Makoto MINATOGAWA

Key Words：blood incompatibility，hemolytic jaundice，carboxyhemoglobin，heme oxygenase

　新生児血液型不適合溶血性黄疸において，ビリルビン産生の律速段階酵素ヘムオキシゲナーゼはビリルビン，COを同量産生するため，血中COHbはビリルビン産生の有効な指標である。我々は，新生児血液型不適合溶血性黄疸におけるCOHbの診断的有用性を検討した。対象は平成18年1月～21年6月に当院NICUで加療された在胎36週以降出生の血液型不適合溶血性黄疸（溶血群）20例，非血液型不適合黄疸（非溶血群）51例である。入院時COHb，入院中最高COHbはそれぞれ溶血群が非溶血群に比べ有意に高かった（1.7±0.7 vs 0.9±0.2％，p＜0.0001），（1.8±0.7 vs 1.0±0.2％，p＜0.0001）。交換輸血が必要な重症例を検出するために入院時COHb≧2.2％を用いた場合の精度は感度，特異度共に100％であった。日常的に簡便に測定可能なCOHbは新生児溶血性黄疸，交換輸血必要性の予測に有用である。

　Hemolytic jaundice is an important cause of severe hyperbilirubinemia among neonatal population. The rate-limiting enzyme Heme oxygenase（HO）degrades heme into same amount of bilirubin and carbon monoxide（CO）．The CO binds with Hb to form COHb. COHb is considered to be an indicator for the severity of hemolysis. We studied whether COHb in patients with hemolytic jaundice was higher than that of non-hemolytic jaundice. COHb data of 71 patients who were admitted to our facility from January 2006 to June 2009, were collected retrospectively. There were 20 cases with hemolytic jaundice（hemolytic group）and 51 with non-hemolytic jaundice（non-hemolytic group）．There were 20 cases of blood type incompatibility：ABO incompatibility（14cases），RhE incompatibility（3cases），RhC incompatibility（2cases）， Rhc, e, Jra, and Diego（1case each）．On admission, COHb of hemolytic group was significantly higher than that of nonhemolytic group（1.7% vs 0.9%, p= < 0.0001）．During hospitalization, maximum COHb of hemolytic group was significantly higher than that of non-hemolytic group as well. To detect the severe cases who were treated with exchange transfusion（ET），the upper limit of COHb set at 2.2% had 100% of sensitivity and specificity. Conclusion： COHb was useful in diagnosing blood incompatible hemolytic jaundice and in detecting severe cases who needed ET.