Recent trends in neonatal care promote early skin-to-skin contact (SSC) between a mother and her child to improve the delivery experience and the success of breastfeeding, even when delivery is scheduled in the environment of the operating room.1 Recently, SSC has also been suggested during caesarean section, but safety concerns have been raised about this practice in the operating room.2
We describe two cases of electrical interferences in the ECG during caesarean section. Both patients consented for the publication of their cases.
Case 1: A 37-year-old primiparous parturient with no history of cardiac diseases was admitted to the obstetric delivery suite to induce labour. Epidural analgesia was initiated. After 8 h of labour, the obstetricians decided to proceed with a caesarean delivery for cephalic disproportion. The epidural catheter was topped up and standard monitoring [ECG, pulse oximeter and noninvasive blood pressure (BP)] was applied uneventfully. After obtaining a T4 level block, caesarean section was performed: a healthy neonate was delivered, placental extraction was accomplished with no significant bleeding and uterine contraction was obtained with a bolus of 25-μg carbetocin intravenously. After the initial examination the baby was placed on the mother's chest to provide early SSC. Shortly after this the heart rate (HR) alarm was triggered on the monitor due to a dramatic increase of the HR (172 bpm), associated with a supra ventricular, narrow QRS complex and irregular rhythm (Fig. 1). The parturient remained conscious with no complaints. Her radial pulse showed neither arrhythmia nor tachycardia. Noninvasive BP remained normal. The pulse oximeter waveform was unchanged and synchronised with some of the QRS complexes of the ECG. The positioning of the electrocardiographic electrodes was checked, thinking of potential interference the baby's heart electric activity on the mother's ECG trace. The newborn was found suckling the right (red) electrode of the ECG, which was immediately relocated to another site on the mother's skin. The ‘abnormal’ ECG rhythm, which was in fact the sum of the mother's and the baby's ECG, disappeared.
Case 2: A healthy multiparous 36-year-old female, with no history of cardiac disease, presented in labour at 40 weeks of gestation. Despite complete cervical dilatation, the head of the baby did not descend, and the obstetrician decided to perform a caesarean section. After an uneventful spinal anaesthetic, haemodynamic stability (sinus rhythm of approximately 70 bpm and BP of 110/60 mmHg) was maintained throughout the procedure. A healthy boy was born with an Apgar score of 10 after 1 and 5 min. The umbilical cord was cross-clamped, and 5 unit of oxytocin were administered intravenously. Placental delivery was performed immediately with no significant bleeding. The baby was placed on the bare skin of his mother's chest and both were covered with warm blankets. During this intimate contact, the monitor alarm went off; the ECG changed to a narrow complex tachycardia (Fig. 2). The plethysmograph recording and BP remained unchanged, but there seemed to be two different ECG rhythms in one recording. Inspection of the neonate showed that he had taken the right ECG lead in his hand (Fig. 3). After cautious replacement of this lead on the mother's right shoulder, the ECG returned to normal sinus rhythm.
These two cases illustrate that electrocardiographic interference can be observed during caesarean delivery and SSC is one of the possible causes as a result of the baby suckling or touching an ECG electrode: in these conditions the cardiac electric activity of the baby can merge with his mother's.
The most common causes of ECG interference are related to the patient themselves, to a dysfunction of the ECG electrodes or cables, or to external causes.3 In the obstetric environment, very little evidence exists concerning electric interference on the ECG. Only Marples has described a case of electric artefacts during labour, with a transcutaneous electrical nerve stimulator used for labour analgesia.4
The capture of the neontate's ECG signal on the mother's ECG trace during caesarean section was unexpected, especially when the mother and the child were separated. In the literature to date, no accidental fusion of ECG rhythms has been described during surgery, even though the same recording pattern can be obtained deliberately to diagnose foetal congenital heart diseases in utero, when a foetal ECG trace cannot be obtained in isolation.5
This novel source of electric interference represents a hazard for both the mother and the neonate: the tachycardia alarm on the monitor could have led to a misdiagnosis of a supraventricular arrhythmia, and the administration of antiarrhythmic drugs, or even worse, the application of synchronised direct current shock to the mother. This type of iatrogenic event following a misdiagnosed arrhythmia has already been reported6 and is avoidable if identified.
In our case, the artefact was identified as a consequence of a mismatch between the ECG and the pulse oximeter signal and conscious state of the patient. Other authors recommend ensuring that the ECG change is not an artefact when (1) it occurs without any haemodynamic changes on the pulse oximeter or arterial pressure waveforms, (2) there is good correlation between maternal peripheral and apical pulses, (3) the sequence of onset and disappearance of the arrhythmia is associated with giving the baby to or taking the baby away from the mother, (4) in association with a change of position of the baby.3
Perinatal care was demonstrated to be improved by optimal training of the obstetric team for critical incidents.7 Concerning the implementation of SSC in our labour wards and obstetric operating rooms, the team should be aware of the potential consequences of this relatively new practice so as to avoid unnecessary complications.
In conclusion, when planning SSC in the operating room, we recommend ECG electrodes to be placed where no contact will be possible with the neonate (at the posterior side of the shoulders for example) to allow adequate cardiac monitoring of the mother and avoid ECG interference from the child upon skin contact after delivery.
Acknowledgements relating to this article
Assistance with the letter: we would like to thank Dr J. Puertas, Prof F. Gilsanz and Dr E. Matute for their contribution to the preparation and publication of the article.
Financial support and sponsorship: none.
Conflicts of interest: none.
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