title: Early neonatal hyperkalaemia in the extremely premature newborn infant.
abstract: The incidence of hyperkalaemia in 43 consecutive infants born at less than 28 weeks gestation and cared for in our neonatal intensive care unit was documented. Plasma K levels were related to indices of renal function as well as to the degree of illness in the infants. The mean gestational age was 26.0 weeks (range 24-27 weeks) and the mean birthweight was 815 g (range 395-1170 g). Twenty-six of the infants (60%) had at least one plasma K greater than 5.5 mmol/L and 13 (30%) had a maximum plasma K greater than 7 mmol/L. The mean postnatal age at which the plasma K exceeded 7 mmol/L was 25 h (range 10-39 h). Five infants with plasma K greater than 7 mmol/L developed cardiac arrhythmias and four died of this complication. Only one infant had a large intraventricular haemorrhage. Only two of 16 infants with an initial plasma K less than 5 mmol/L had a maximum plasma K greater than 7 mmol/L, compared with eight of 10 with an initial plasma K greater than 6 mmol/L (P less than 0.005). Plasma K also correlated directly with plasma urea (P less than 0.001) and plasma creatinine (P less than 0.025), and inversely with urine volume (P less than 0.05). Plasma K did not correlate with K intake, arterial pH, presence of asphyxia, severity of respiratory illness, gestation or birthweight. The rapidity with which the plasma K concentration reached potentially hazardous levels in some infants makes it imperative to measure plasma K within 6 h of birth and to continue to monitor levels at least every 6 h for the first 48 h in all infants born at less than 28 weeks gestation.
authors.affiliation: Department of Neonatology, Royal North Shore Hospital, St Leonards, New South Wales, Australia.
authors.forename: G I
authors.initials: GI
authors.lastname: Leslie
authors.forename: G
authors.initials: G
authors.lastname: Carman
authors.forename: J D
authors.initials: JD
authors.lastname: Arnold
mesh_terms: D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000401:mortality; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D006947:Hyperkalemia / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D015994:Incidence; D007231:Infant, Newborn; D007234:Infant, Premature; D007363:Intensive Care Units, Neonatal; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D012189:Retrospective Studies