Sleep Medicine Reviews 18 (2014) 101e102
Contents lists available at ScienceDirect
Sleep Medicine Reviews journal homepage: www.elsevier.com/locate/smrv
GUEST EDITORIAL
Sleep in the pediatric intensive care unit Though sleep disruption is commonly encountered in infants and children admitted to the pediatric intensive care unit (PICU), there is limited published information about its characteristics and the influence it may have on the acute illness or the recovery process. Sleep disturbance in the intensive care setting is an enormously complex process occurring in a heterogenous population. The age range of the admitted patient is anywhere from one month to adolescence. The illness that triggers the PICU admission may be inflammatory, traumatic, metabolic, toxic, neoplastic or iatrogenic in nature. Further, it may involve single or multiple organ systems. The impact of sleep disruption on the outcome of the critically ill child is variable, depending upon the level of maturation of sleep wake regulatory systems and overall neurodevelopmental stage e the younger the child, the greater is the likelihood of enduring impairment of essential postnatal maturational processes such as myelination, synaptogenesis or the regulation of emotional control. The nature of sleepewake problems is also quite diverse, ranging from circadian rhythm disruption with internal desynchronization, to altered control of breathing, neurological complications such as coma and seizures, to iatrogenic complications and emotional disturbance. A whole host of factors influence the sleep of a child who has been admitted to the PICU. The preexisting emotional or neuropsychological profile of the child may be a pre-determinant. For instance, McCarthy et al. have found that a preexisting psychosocial condition influenced the outcome in the first year after closed head injury in childhood [1]. One must also consider the nature of the medical illness that leads to the PICU admission. For instance, a brief post-operative admission for elective surgery is likely to have minimal consequences when compared with a totally unanticipated closed head injury that is accompanied by multi-organ damage and a prolonged hospital stay. Extrinsic factors such as noise, light, interventions by care providers and medications may also serve as precipitating or perpetuating factors for the sleep disturbance. Although sleep e wake problems develop during the acute hospitalization, they tend to sometimes persist well beyond discharge to home, as in closed head injury [1]. In an excellent review of sleep in the pediatric intensive care unit, Kudchadkar et al. screened 3153 articles and ultimately summarized the results of nine studies pertaining to sleep in the PICU [2]. Seven of the nine studies utilized polysomnography while two used behavioral sleep questionnaires. One of the notable observations was in children who had sustained burns e they showed a marked reduction in the proportion of slow wave and REM sleep during the acute phase, with gradual normalization of sleep architecture over a month [3]. The changes in sleep architecture in burn patients may be the consequence of a burn encephalopathy, 1087-0792/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.smrv.2013.11.003
electrolyte imbalance or medication effect. This study of Gottslich et al. from the University of Cincinnati was conducted in 1994. Similar prospective studies are much needed again, given changes in sleep technology and the recent standardization of pediatric polysomnogram recording and scoring techniques [4]. A second important point stressed in the Kudchadkar et al. paper was the poor correlation between bedside behavioral observations and polysomnography about whether a child was asleep or awake (kappa of only 0.21). Children judged to be asleep by visual assessment were awake by polysomnogram assessment 56.3% of the time [2,5]. This underscores the importance of utilizing clinical neurophysiologic techniques, to the extent possible, in assessing whether a patient is truly asleep as some of the nursing cares and procedures which are carried out are state dependent (such as postural drainage therapy conducted during wakefulness). The tendency for increased sleep fragmentation in mechanically ventilated patients who are on pressure support as compared to assist control ventilation is also discussed. Traditionally, electroencephalogram (EEG) recordings in the PICU have been utilized to monitor for subclinical seizures or to assess prognosis based upon visually discernible patterns such as suppression burst, alpha coma or isoelectric pattern. This type of clinical EEG evaluates cortical activity at frequencies of 1 to several hundred Hz. In 1993, however, Steriade and co-workers described a new type of slow oscillation (
Contents lists available at ScienceDirect
Sleep Medicine Reviews journal homepage: www.elsevier.com/locate/smrv
GUEST EDITORIAL
Sleep in the pediatric intensive care unit Though sleep disruption is commonly encountered in infants and children admitted to the pediatric intensive care unit (PICU), there is limited published information about its characteristics and the influence it may have on the acute illness or the recovery process. Sleep disturbance in the intensive care setting is an enormously complex process occurring in a heterogenous population. The age range of the admitted patient is anywhere from one month to adolescence. The illness that triggers the PICU admission may be inflammatory, traumatic, metabolic, toxic, neoplastic or iatrogenic in nature. Further, it may involve single or multiple organ systems. The impact of sleep disruption on the outcome of the critically ill child is variable, depending upon the level of maturation of sleep wake regulatory systems and overall neurodevelopmental stage e the younger the child, the greater is the likelihood of enduring impairment of essential postnatal maturational processes such as myelination, synaptogenesis or the regulation of emotional control. The nature of sleepewake problems is also quite diverse, ranging from circadian rhythm disruption with internal desynchronization, to altered control of breathing, neurological complications such as coma and seizures, to iatrogenic complications and emotional disturbance. A whole host of factors influence the sleep of a child who has been admitted to the PICU. The preexisting emotional or neuropsychological profile of the child may be a pre-determinant. For instance, McCarthy et al. have found that a preexisting psychosocial condition influenced the outcome in the first year after closed head injury in childhood [1]. One must also consider the nature of the medical illness that leads to the PICU admission. For instance, a brief post-operative admission for elective surgery is likely to have minimal consequences when compared with a totally unanticipated closed head injury that is accompanied by multi-organ damage and a prolonged hospital stay. Extrinsic factors such as noise, light, interventions by care providers and medications may also serve as precipitating or perpetuating factors for the sleep disturbance. Although sleep e wake problems develop during the acute hospitalization, they tend to sometimes persist well beyond discharge to home, as in closed head injury [1]. In an excellent review of sleep in the pediatric intensive care unit, Kudchadkar et al. screened 3153 articles and ultimately summarized the results of nine studies pertaining to sleep in the PICU [2]. Seven of the nine studies utilized polysomnography while two used behavioral sleep questionnaires. One of the notable observations was in children who had sustained burns e they showed a marked reduction in the proportion of slow wave and REM sleep during the acute phase, with gradual normalization of sleep architecture over a month [3]. The changes in sleep architecture in burn patients may be the consequence of a burn encephalopathy, 1087-0792/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.smrv.2013.11.003
electrolyte imbalance or medication effect. This study of Gottslich et al. from the University of Cincinnati was conducted in 1994. Similar prospective studies are much needed again, given changes in sleep technology and the recent standardization of pediatric polysomnogram recording and scoring techniques [4]. A second important point stressed in the Kudchadkar et al. paper was the poor correlation between bedside behavioral observations and polysomnography about whether a child was asleep or awake (kappa of only 0.21). Children judged to be asleep by visual assessment were awake by polysomnogram assessment 56.3% of the time [2,5]. This underscores the importance of utilizing clinical neurophysiologic techniques, to the extent possible, in assessing whether a patient is truly asleep as some of the nursing cares and procedures which are carried out are state dependent (such as postural drainage therapy conducted during wakefulness). The tendency for increased sleep fragmentation in mechanically ventilated patients who are on pressure support as compared to assist control ventilation is also discussed. Traditionally, electroencephalogram (EEG) recordings in the PICU have been utilized to monitor for subclinical seizures or to assess prognosis based upon visually discernible patterns such as suppression burst, alpha coma or isoelectric pattern. This type of clinical EEG evaluates cortical activity at frequencies of 1 to several hundred Hz. In 1993, however, Steriade and co-workers described a new type of slow oscillation (
