Martin P. Samuels

Fourteen cases of imposed upper airway obstruction.

Imposed upper airway obstruction was diagnosed as the cause of recurrent and severe cyanotic episodes in 14 patients. Episodes started between 0.8 and 33 months of age (median 1.4) and occurred over a period of 0.8 to 20 months (median 3.5). Diagnosis was made by covert video surveillance, instituted after either (a) the observation that episodes began only in the presence of one person, or (b) characteristic findings on physiological recordings, lasting between 12 hours and three weeks, performed in hospital or at home. Surveillance was undertaken for between 15 minutes and 12 days (median 24 hours) and resulted in safety for the patient and psychiatric assessment of the parent: mother (n = 12), father (n = 1), and grandmother (n = 1). These revealed histories of sexual, physical, or emotional abuse (n = 11), self harm (n = 9), factitious illness (n = 7), eating disorder (n = 10), and previous involvement with a psychiatrist (n = 7). Management of the abusing parents is complex, but recognition of their psychosocial characteristics may allow earlier diagnosis. Imposed upper airway obstruction should be considered and excluded by physiological recordings in any infant or young child with recurrent cyanotic episodes. If physiological recordings fail to substantiate a natural cause for episodes, covert video surveillance may be essential to protect the child from further injury or death.

The Relationship between Bradycardia, Apnea, and Hypoxemia in Preterm Infants

ABSTRACT: The pathogenesis of bradycardias in preterm infants is poorly understood. Because their pathogenesis may involve both apnea and hypoxemia, we set out to analyze the proportion of bradycardias that were associated with an apneic pause and/or a fall in arterial oxygen saturation (Sao2), and the temporal sequence of the three phenomena, in overnight tape recordings of Sao2 (Nellcor N100 in beat-to-beat mode), breathing movements, nasal airflow, and ECG in 80 preterm infants at the time of discharge from hospital. A bradycardia was defined as a fall in heart rate of ≥33% from baseline for ≥4 s, an apneic pause as a cessation of breathing movements and/or airflow for ≥4 s, and a desaturation as a fall in Sao2 to ≤80%. A total of 193 bradycardias were found in 46 (58%) of the recordings (median, three per recording; range 1–18). There was a close relationship between bradycardias, apneic pauses, and desaturations: 83% of bradycardias were associated with apneic pauses and 86% with desaturations. Where all three phenomena occurred in combination, the time from the onset of apnea to the onset of the fall in Sao2 was shorter (median interval, 0.8 s; range −4.9-+11.5 s) than that from the onset of apnea to the onset of bradycardia (median, 4.8 s; range −4.0-+14.0 s). Hence, most bradycardias (86%) commenced after the onset of the fall in Sao2. We conclude that bradycardia, apnea, and hypoxemia are closely linked phenomena in preterm infants.

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.

Epidemiology and Pathophysiology of Apnoea of Prematurity

In preterm infants, reliance on the detection of apnoeic pauses and/or bradycardia results in significant amounts of hypoxaemia remaining undetected. In addition, recordings of breathing movements and ECG do not have predictive value for subsequent sudden infant death. In recent years, the ability to continuously monitor and record arterial oxygen saturation (SaO2) has produced important information regarding the mechanisms for respiratory events in the preterm population. Normal data on SaO2 (Nellcor N-200) and breathing movements have been collected in 160 preterm infants. Median baseline SaO2 during regular breathing was 99.5% (range 88.7-100) at the time of discharge from SCBU and 100% (95.3-100) at follow-up 6 weeks later. Episodic desaturations (SaO2 < or = 80% for > or = 4 s) ranged between 0 and 355 episodes per 12-hour recording. In a study of a separate group of 16 preterm infants with recurrent cyanotic episodes of unknown cause, the total number of abnormal hypoxaemic episodes was markedly increased. These hypoxaemic episodes were associated with three breathing pattern: (i) absent breathing movements; (ii) continued breathing movements, but absent airflow, and (iii) continuous airflow and breathing movements. Thus, preterm infants with cyanotic episodes have an increased number of clinically unapparent hypoxaemic episodes, some of which occur with continued breathing and airflow. In another study of 79 patients who had been born preterm and had a history of an apparent life-threatening event, 43 (54%) had abnormal oxygenation on multichannel recordings, including 23% with clinically undetected baseline hypoxaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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 (SaO:) below baseline for a median duration of 100s and <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.

Classification of child abuse by motive and degree rather than type of injury

The protection of children may be enhanced if ill treatment is classified by motive and degree rather than by type of injury. Four categories are proposed: A, abuse: premeditated ill treatment undertaken for gain by disturbed, dangerous, and manipulative individuals; B, active ill treatment: impulsively undertaken because of socioeconomic pressures, lack of education, resources, and support, or mental illnesses; C, universal mild ill treatment: behaviour undertaken by all normal caring parents in all societies; and D, neglect: defined here as an unintentional failure to supply the child’s needs. Such a classification could clarify the procedures for investigation and protection, and support the creation of a Special Interagency Taskforce on Criminal Abuse (SITCA) for those suspected of abuse (category A).

How to distinguish between neglect and deprivational abuse.

Neglect is a major cause of inadequate childcare in all societies and should be differentiated from abuse. “Neglect” is defined here, as the “neglectful” failure to supply the needs of the child, including emotional needs. It does not include the deliberate and malicious withholding of needs, which is a form of abuse. Neglect has its roots in ignorance of a child’s needs and competing priorities; it is passive and usually sustained. The carer is without motive and unaware of the damage being caused. Malnutrition is a prime example of neglect; the stigma associated with the term abuse should never be applied to the poor struggling or uneducated mother whose child, that she loves dearly, becomes malnourished. Education of the mother and society and relief from the vicissitudes of poverty are required to alleviate most neglect of the world’s children.

Abnormal hypoxemia after life-threatening events in infants born before term

This study aimed to determine whether preterm infants who have a history of apparent life-threatening events (ALTE) have abnormalities in oxygenation and, if so, whether the ALTE would stop with oxygen therapy. We assessed 92 patients (median gestational age at birth, 32 weeks (range, 24 to 36 weeks); median birth weight, 1840 gm (650 to 3500 gm)) who had had a single (n = 20) or recurrent ALTE. Median postnatal age at referral was 3.2 months (0.5 to 44.7 months). All had been considered otherwise free of symptoms and adequately oxygenated in air at the time of discharge from their neonatal unit, before the ALTE. Fifty-two patients had received mouth-to-mouth resuscitation, and 40 vigorous stimulation. Ninety-one patients underwent 8- to 12-hour recordings of arterial oxygen saturation, the plethysmographic waveforms from the oximeter, breathing movements, and electrocardiograms. These recordings were compared with previously published data from 110 healthy preterm infants made at around 6 weeks after discharge from hospital. Compared with these data, 49 recordings (54%) were normal, 19 showed abnormal hypoxemic episodes, 6 had abnormally low baseline arterial oxygen saturation (< 95%), and 17 had both. In 31 of 33 patients, ALTE stopped or were reduced in frequency or severity after additional inspired oxygen (0.1 to 1.0 L/min via nasal cannulas) was given. Oxygen was given for a median duration of 3.9 months (range, 0.8 to 17.2 months). Persistent events in the remaining two patients were subsequently found to be due to intentional suffocation in one and epileptic seizures in the other. Monitoring of transcutaneous oxygen tension at home was undertaken in 84 patients. To date, this has been discontinued in 81 after a median duration of 7.3 months (0.3 to 18.9 months). We conclude that recognition and treatment of abnormalities in episodic or baseline hypoxemia may reduce the risk of further ALTE in previously preterm infants.

Small airway patency in infants with apparent life-threatening events

Abstract A reduction in specific airway conductance has been reported in infants with a history of an apparent life-threatening event (ALTE). It is unclear, however, whether this reflects upper or lower airway narrowing. We performed a controlled study to determine small airway patency in infants with ALTE. Lung function tests were performed in 26 infants with a history of ALTE and 27 healthy controls. Partial expiratory flow-volume curves were obtained during quiet sleep using the rapid chest compression technique; thoracic gas volume (TGV) and expiratory airway resistance (RAW) were measured by whole body plethysmography. Compliance of the respiratory system (Crs) was measured using the single breath occlusion technique. The median maximal flow at functional residual capacity (V˙maxFRC) was 85u2009ml/s (range 10–198u2009ml/s) in patients and 123 (range 47–316u2009ml/s) in controls (Pu2009=u20090.003). V˙maxFRC corrected for TGV was 0.5 s−1 (range 0.06–1.3 s−1) and 0.9 s−1 (range 0.4–1.8 s−1), respectively (Pu2009=u20090.001). TGV, RAW and Crs were not significantly different between patients and controls.nConclusion Reduced small airway patency may play a role in the pathogenesis of ALTE.