Editorial Commentary on Pediatric Sleep Disorders

In this issue of Sleep and Hypnosis, Erler et al., compare the reliability of thoracic impedance and inductive pletismography to assess respiratory movements. Respiratory efforts and chest wall/abdominal expansions are usually recorded as changes in pneumatic bellows, strain gauges or respiratory inductive plethysmographic (RIP) waveforms. RIP is a noninvasive method, directly related to tidal volume. Brouillette et al. showed that polysomnography using RIP with automatic calibration was highly accurate in detecting both central and obstructive apnea in infants and children (1). Transthoracic impedance (TI) is the usual method of recording respiratory efforts using home and hospital infant apnea monitors. Because transthoracic impedance is not capable of distinguishing obstructed from unobstructed breaths (1), it is not recommended for sleep laboratory use. Such studies as pneumograms and event recordings that are based on transthoracic impedance should not be used to evaluate obstructive sleep apnea. Infants frequently experience apnea, which may result in bradycardia or even in life-treathening events. Therefore it is very important to correctly assess and evaluate infants’ respiratory movements and choose the best method in order to have the best signal reliability. Event recording, by differentiating between true and false events, has advanced the diagnosis and management of infants on home cardiorespiratory monitors; however, the pathogenesis of many events remains obscure. The article reviewed polysomnographic studies of 52 infants (34 healthy infants recruited as part of campaign to prevent SIDS, 9 infants suffering from bronchopulmonary dysplasia and 9 infats with clinical suspicion of apnea syndrome) with simultaneous recording of RIP and TI. Authors demonstrate that RIP has a higher sensitivity for sleep apnea detection (99.5%) than TI (98.2%), but a lower specificity. They show that each methods has pros and cons. Main problems of TI are misinterpretation of cardiac artifacts as apparent breathing activity, impaired detection of obstructive events and differentiation of paradoxical breathing. IP has advantages in recognizing true apneas but give a high rate of false positive. A recent computerised audiovisual event recording system by elucidating infant behaviours, provides information complementary to that given by cardiorespiratory event recording. Infant monitors of the future should incorporate both audiovisual and cardiorespiratory data to elucidate optimally apparent life-threatening events, apnoeas and bradycardias (2). Since no other standardized methods are actually avalilable we should follow the suggestions given by the Authors on this article that the simultaneous use of both methods permit to achieve the best detection of apneas (near 100%). However, the final decision on which is the best method depends on indication: for impatient treatment TI provides precise detection of apneas; furhter TI is easier to set and costs Editorial Commentary on Pediatric Sleep Disorders