Hypoxaemia and cardiorespiratory changes during epileptic seizures in young children.

In order to measure epileptic seizure(ES)-induced hypoxaemia and explore its relation to other physiological changes, 53 seizures were documented in 10 children (aged 1 week to 5 years) during continuous recordings of breathing, ECG, oxygenation and EEG. Hypoxaemia was demonstrated in 42 ESs with an arterial oxygen saturation (SaO2) below baseline for a median duration of 100s and < or = 60% for 17s, despite resuscitation. There were pauses in breathing movements in 45 seizures, but only 35 of these were hypoxaemic; pauses of comparable severity occurred in the 10 seizures without hypoxaemia. In seven seizures there was hypoxaemia without pauses in breathing movements, although continued nasal airflow was not demonstrable. Sinus tachycardia occurred in 35 seizures and T-wave changes in 20, but no sinister arrhythmias were observed.

Epileptic seizure-induced hypoxemia in infants with apparent life-threatening events.

OBJECTIVE: To describe the physiologic changes that occur during epileptic seizure (ES)-induced apparent life-threatening events (ALTE) and to provide an explanation for the mechanism whereby the hypoxemia characterizing these events occurred. PATIENTS AND DESIGN: Six infants were retrospectively selected from a group of 17 because they had ALTE documented on physiologic recordings where the first change in signals was in the electroencephalogram (EEG). The 17 infants had clinical features suggestive of partial seizures (but normal standard EEGs) and were from a sample of 172 infants with recurrent ALTE. All 17 infants underwent continuous recordings of breathing, electrocardiogram (ECG), oxygenation, and EEG, but only in 6 was an ES-induced ALTE recorded and the physiologic changes described. RESULTS: Twenty-three ALTE were documented in six infants. Events commenced with an abnormality in the EEG, followed by a decrease in SaO2 after a median interval of 27 seconds (range 2 to 147). Despite resuscitation, the median duration of severe hypoxemia (SaO2 < or = 60%) was 40 seconds (range 8 to 74). In 18 events (five infants) there was a median of four apneic pauses (range 1 to 9) preceding the decrease in SaO2 by a median duration of 24 seconds (range 3 to 48). The longest apneic pause per event lasted a median of 19 seconds (range 8 to 47). Breathing movements continued in five events (four infants), and expiratory airflow in one. Sinus tachycardia was found in 19 of the 23 events (six infants), but there were no cardiac arrhythmias. CONCLUSIONS: ES in infants can manifest as ALTE and be accompanied by potentially life-threatening episodes of severe hypoxemia and apnea, despite a normal EEG between events.

Home event recordings of oxygenation, breathing movements, and heart rate and rhythm in infants with recurrent life-threatening events.

For an evaluation of the usefulness of event recording in identifying mechanisms for apparent life-threatening events, 94 infants (median age, 3.1 months; range, 0.5 to 12 months) with a history of two or more apparent life-threatening events of hitherto unknown cause underwent event recording of transcutaneous oxygen pressure, arterial oxygen saturation, (not recorded in all patients), breathing movements, pulse waveforms, electrocardiogram, and instantaneous heart rate. Recordings were triggered by a fall in transcutaneous oxygen pressure to less than 20 mm Hg. During a median duration of event recording of 1.3 months (0.1 to 10 months), 52 events were recorded in 34 patients; 7 of the events had to be excluded because of uninterpretable signals. The following mechanisms were identified in the remaining 30 patients (45 events): a sudden change in skin perfusion but without hypoxemia (6 in 5 patients), hypoxemia induced by an epileptic seizure (6 in 5 patients), hypoxemia induced by suffocation by a parent (4 in 4 patients), and parental fabrication of events and medical history (7 in 6 patients). In the remaining 22 events in 12 patients, the precise mechanism of events could not be identified. Analysis of these as-yet-unexplained events showed prolonged abnormal hypoxemia (a fall in transcutaneous oxygen pressure to between 4 and 18 mm Hg and a fall in arterial oxygen saturation to 5% to 75%), lasting for 40 to 500 seconds in all. Only five of these events involved prolonged (> 20 seconds) apneic pauses, and only four an episode of bradycardia (heart rate < 80 or 60 beats/min). Thus event recording identified various mechanisms of apparent life-threatening events. In the events that remained unexplained, prolonged apneic pauses or episodes of bradycardia were found in only a minority. The identification of hypoxemia therefore may be more relevant to the early detection of these events than the identification of apnea or bradycardia or both. The relevance of these findings with regard to sudden infant death syndrome remains to be determined.

Diagnosis and management after life threatening events in infants and young children who received cardiopulmonary resuscitation.

OBJECTIVE: To determine the mechanisms and thereby appropriate management for apparent life threatening events treated with cardiopulmonary resuscitation in infants and young children. DESIGN: Prospective clinical and physiological study. SETTING: Royal Brompton Hospital or in patients' homes, or both. SUBJECTS: 157 Patients referred at median age 2.8 months (range 1 week to 96 months), 111 (71%) had recurrent events, 44 were born preterm, 19 were siblings of infants who had died suddenly and unexpectedly, and 18 were over 12 months old. INTERVENTIONS: Multichannel physiological recordings, including oxygenation, in hospital (n = 150) and at home (n = 61). Additional recordings with electroencephalogram, video, or other respiratory measures were used to confirm diagnoses. Management involved monitoring of oxygen at home, additional inspired oxygen, anticonvulsant treatment, or child protection procedures. MAIN OUTCOME MEASURES: Abnormalities on recordings compared to published normal data and their correlation with clinical events; sudden death. RESULTS: 53 of 150 patients had abnormalities of oxygenation on hospital recordings, 28 of whom had an accompanying clinical event. Home recordings produced physiological data from 34 of 61 patients during subsequent clinical events. Final diagnoses were reached in 77 patients: deliberate suffocation by a parent (18), hypoxaemia induced by epileptic seizure (10), fabricated history and data (Munchausen syndrome by proxy; seven), acute hypoxaemia of probable respiratory origin (40), and changes in peripheral perfusion and skin colour without hypoxaemia (two). Four patients died: three suddenly and unexpectedly (none on home oxygen monitors) and one from pneumonia. CONCLUSIONS: Identification of mechanisms is essential to the appropriate management of infants with apparent life threatening events.