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Severe bradycardia in an extremely low birth weight preterm infant with hyperkalaemia
Resuscitation 82 (2011) 640–641
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Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Letter to the Editor Severe bradycardia in an extremely low birth weight preterm infant with hyperkalaemia Sir, On the seventh day after delivery, a preterm infant (29 weeks gestational age; birth weight = 725 g) receiving non-invasive respiratory support (N-CPAP FiO2 of 0.23) but otherwise healthy, developed severe bradycardia (minimum heart rate 35–40/min) with good oxygen saturation (SpO2 99%). External cardiac massage and manual ventilation were promptly started without an increase in the heart rate. The infant was intubated, mechanically ventilated and external cardiac massage was performed continuously.
Fig. 2. Electrocardiogram during a phase of mild hyperkalaemia (K+ 9.8 mmol L−1 ), showing a partial normalization (no QRS widening, only peaking T wave).
Fig. 1. Electrocardiogram during extreme hyperkalaemia (K+ 14.3 mmol L−1 ) showing severe bradycardia and QRS widening. 0300-9572/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2010.12.023
A serum potassium level of 14.3 mmol L−1 was measured and confirmed in two samples obtained from the central venous catheter. Parenteral nutrition was suspended immediately. Dopamine, adrenaline, insulin, and sodium bicarbonate were given intravenously but the heart rate did not increase. Sodium polystyrene sulphonate (Kayexalate, 1 g kg−1 per os) was started. After 90 min of continuous external cardiac massage, the heart rate increased during a partial exchange transfusion with 20 ml of O Rhesus negative blood, after which the serum potassium level decreased under 8 mmol L−1 . The potassium value decreased over the next 24 h to less than 4.5 mmol L−1 . Electrocardiographic (ECG) monitoring showed the characteristic changes of hyperkalaemia such as peaking of T waves ad QRS widening (Fig. 1), with partial normalization occurring only when the serum potassium level decreased below 10 mmol L−1 (Fig. 2). On measuring the potassium concentration in the parenteral nutrition bag, it was shown to be ten times higher than that prescribed. Cerebral MRI performed at 40 week’s gestation did not show any correlated cerebral damage. This case demonstrated that a prolonged external cardiac massage and intensive care were helpful to maintain circulation during severe bradycardia caused by iatrogenic hyperkalaemia. The finding of a normal ECG only with a serum potassium level lower than
Letter to the Editor / Resuscitation 82 (2011) 640–641
10 mmol L−1 , may indicate that the tolerance of the myocardium to hyperkalaemia in extremely preterm and low birth weight infants has a threshold. This has been suggested previously.1 It is also possible that the absence of renal failure and sepsis in this infant may have enabled a higher tolerance to severe hyperkalaemia. Conflict of interest statement The authors have no conflict of interest to declare. Reference 1. De Luca D, Paolillo P. Absence of arrhythmias in the extremely preterm heart with severe hyperkalaemia. Resuscitation 2009;80:961.
641
Gianluca Lista Petrina Bastrenta ∗ Francesca Castoldi Neonatal Intensive Care Unit, V. Buzzi Children’s Hospital, ICP, via Castelvetro 32, Milan, Italy Fabio Meneghin Gianvincenzo Zuccotti Department of Pediatrics, L Sacco Hospital, University of Milan, Milan, Italy ∗ Corresponding author. E-mail address: [email protected] (P. Bastrenta)
30 December 2010
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Letter to the Editor Severe bradycardia in an extremely low birth weight preterm infant with hyperkalaemia Sir, On the seventh day after delivery, a preterm infant (29 weeks gestational age; birth weight = 725 g) receiving non-invasive respiratory support (N-CPAP FiO2 of 0.23) but otherwise healthy, developed severe bradycardia (minimum heart rate 35–40/min) with good oxygen saturation (SpO2 99%). External cardiac massage and manual ventilation were promptly started without an increase in the heart rate. The infant was intubated, mechanically ventilated and external cardiac massage was performed continuously.
Fig. 2. Electrocardiogram during a phase of mild hyperkalaemia (K+ 9.8 mmol L−1 ), showing a partial normalization (no QRS widening, only peaking T wave).
Fig. 1. Electrocardiogram during extreme hyperkalaemia (K+ 14.3 mmol L−1 ) showing severe bradycardia and QRS widening. 0300-9572/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2010.12.023
A serum potassium level of 14.3 mmol L−1 was measured and confirmed in two samples obtained from the central venous catheter. Parenteral nutrition was suspended immediately. Dopamine, adrenaline, insulin, and sodium bicarbonate were given intravenously but the heart rate did not increase. Sodium polystyrene sulphonate (Kayexalate, 1 g kg−1 per os) was started. After 90 min of continuous external cardiac massage, the heart rate increased during a partial exchange transfusion with 20 ml of O Rhesus negative blood, after which the serum potassium level decreased under 8 mmol L−1 . The potassium value decreased over the next 24 h to less than 4.5 mmol L−1 . Electrocardiographic (ECG) monitoring showed the characteristic changes of hyperkalaemia such as peaking of T waves ad QRS widening (Fig. 1), with partial normalization occurring only when the serum potassium level decreased below 10 mmol L−1 (Fig. 2). On measuring the potassium concentration in the parenteral nutrition bag, it was shown to be ten times higher than that prescribed. Cerebral MRI performed at 40 week’s gestation did not show any correlated cerebral damage. This case demonstrated that a prolonged external cardiac massage and intensive care were helpful to maintain circulation during severe bradycardia caused by iatrogenic hyperkalaemia. The finding of a normal ECG only with a serum potassium level lower than
Letter to the Editor / Resuscitation 82 (2011) 640–641
10 mmol L−1 , may indicate that the tolerance of the myocardium to hyperkalaemia in extremely preterm and low birth weight infants has a threshold. This has been suggested previously.1 It is also possible that the absence of renal failure and sepsis in this infant may have enabled a higher tolerance to severe hyperkalaemia. Conflict of interest statement The authors have no conflict of interest to declare. Reference 1. De Luca D, Paolillo P. Absence of arrhythmias in the extremely preterm heart with severe hyperkalaemia. Resuscitation 2009;80:961.
641
Gianluca Lista Petrina Bastrenta ∗ Francesca Castoldi Neonatal Intensive Care Unit, V. Buzzi Children’s Hospital, ICP, via Castelvetro 32, Milan, Italy Fabio Meneghin Gianvincenzo Zuccotti Department of Pediatrics, L Sacco Hospital, University of Milan, Milan, Italy ∗ Corresponding author. E-mail address: [email protected] (P. Bastrenta)
30 December 2010