日本未熟児新生児学会雑誌　第19巻　第1号　65～69頁（2007年）

日本未熟児新生児学会雑誌　19(1)：65-69；2007　

受付日：平成17．06．08

受理日：平成18．02．03

未熟児・新生児に対する輸血の指標としての静脈血乳酸値

Effect of Transfusion on Venous Blood Lactate Level in Newborn Infants

産業医科大学　小児科

Department of Pediatrics, School of Medicine, University of Occupational and Environmental Health

高橋大二郎・白川嘉継・白幡　聡

Daijiro TAKAHASHI，Yoshitsugu SHIRAKAWA，Akira SHIRAHATA

Key Words：Venous blood lactate，blood transfusion

　動脈血乳酸値が輸血の指標の一つとなり得るとの報告が散見される。われわれは新生児への輸血に対する静脈血乳酸値（以下，乳酸値）の有用性を明らかにするために2000年1月から2003年1月に当院NICUに入院し，全身状態が不安定な早期新生児期を除く乳児期にMAP加赤血球輸血を受けた11症例を対象とし診療録から後方視的に検討を行った。対象症例の在胎期間，出生体重，輸血日齢の平均±SDはそれぞれ30週1日±5週3日，1,292±899g，日齢38±29であった。輸血は19回行われ，輸血前後のヘモグロビン値は8.6±2.3g/dLから12.8±1.6g/dLへ有意に増加した（p＜0.0001）。輸血前の乳酸値を40mg/dL以上，30以上40mg/dL未満，20以上30mg/dL未満，20mg/dL未満の４群に分けてその推移を検討したところ，乳酸値が30以上40mg/dL未満，40mg/dL以上の群ではいずれも輸血1日後から4日後にかけて経日的に乳酸値が低下した（p＜0.05）。一方，乳酸値20以上30mg/dL未満，20mg/dL未満の症例群では輸血前後で乳酸値は変化しなかった。以上よりHbが低値でも乳酸値が上昇していない症例は輸血が必要ない可能性がある。

　Arterial blood lactate level has been suggested as a marker of determining the indication for transfusion in several studies. To determine whether venous blood lactate level can serve as such indicator as well, we monitored the venous blood lactate level and hemoglobin before and after transfusion. The study subjects were 11 newborn infants, who were admitted to our Neonatal Intensive Care Unit and were transfused during the period from January 2000 to January 2003. The data on the venous blood lactate and hemoglobin before and 1 day through 4 days after the transfusion were collected retrospectively by referring to the clinical laboratory records. Their gestational age, birth weight and postnatal age at transfusion were 30 weeks and 1 day±5 weeks and 3 days（mean±SD）, 1,292±899 g and 38±29 days, respectively. Total of 19 red blood cell transfusion were performed, resulting in the increase in the hemoglobin level from 8.6 to 12.8 g/dL（p＜0.0001）. The subjects were classified into 4 groups by lactate level before transfusion：≧40 mg/dL；≧30 and ＜40 mg/dL；≧20 and＜30 mg/dL；and＜20 mg/dL. In the two high-lactate groups, the lactate level decreased significantly 1 day after the transfusion（p＜0.05）and continued to be decreased thereafter. However, the lactate level was unchanged in the two low-lactate groups. Thus, low venous blood lactate level is likely to serve as a marker of determining the indication for not transfusing in critically ill newborn infants.