Journal of the Korean Pediatric Society 1991;34(3):303-310.
Published online March 31, 1991.
Serum ionized Ca measured with new ion-selected electrode and Q-oTc interval in newborn infants.
Beom Joo Kim, Chang Hee Han, Heng Mi Kim, Doo Hong Ahn
Department of Pediatrics, School of Medicine Kyungpook National University, Taegu, Korea
신생아에 있어서 새로운 Ion-Selected Electrode로 측정한 혈청 이온화 Ca++ 과 Q-oTc 간격
김범주, 한창희, 김행미, 안두홍
경북대학교 의과대학 소아과학교실
Received: 28 December 1990   • Accepted: 20 February 1991
Abstract
The reliability of electrocardiographic detection of serum ionized Ca level was studied in 13 preterm and 32 full term infants. The concentration of ionized Ca was measured with a new ion-selected electrode, NOVA SP4 (NOVA Biomedical, Waltham, MA USA). The Q-oTc interval correlated with total Ca (r=o.553, p<0.01) and ionized Ca (r= -0.435, p< 0.01) but the Q-Tc interval did not correlate with total and ionized Ca. The concentration of ionized Ca correlated with total Ca (r=0.455, p<0.01) but the predictive values of ionized Ca were poor. When the hypocalcemia was defined as ionized Ca<3.0 mg/dl, 91% of hypocalcemic infants revealed prolonged Q-oTc interval. Ionized Ca was low in 42% of cases when the Q-oTc interval was prolonged and in 2% when the Q-oTc interval was normal. When the hypocalcemia was defined as ionized Ca<3.5mg/dl, 69% of hypocalcemic infants revealed prolonged Q-oTc interval. Ionized Ca was low in 46% of cases when the Q-oTc interval was prolonged and in 10% when the Q-oTc interval was normal. The Q-oTc interval permits reliable screening test for ionized Ca<3.0 mg/dl but not for ionized Ca<3.5 mg/dl.
Key Words: Ionized Ca, Q-oTc interval




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