Defining Levels of Sedation in Pediatric Patients

Abstract

In Response: We thank Anghelescu and Kaplan for raising important issues regarding definitions of states of consciousness that have implications for the safe sedation of children. Anghelescu and Kaplan point out that the definitions we used for conscious and deep sedation [1] are not consistent with those of the American Academy of Pediatrics (AAP) [2]. In our study, we defined conscious sedation as verbalization or purposeful movement (e.g., eye opening) in response to verbal command (loudly calling the child's name) or gentle stimulation (shaking the child's shoulder). We defined deep sedation as verbalization or purposeful movement (e.g., arm withdrawal) in response to an attempt at IV catheter insertion in the hand. We should have used the term "appropriate response" instead of "purposeful movement" in the definition of conscious sedation, and "nonpurposeful movement" to describe arm withdrawal in the definition of deep sedation. We regret that we created confusion with our semantic errors, but they have no bearing whatsoever on our data and conclusions. Although we incorrectly defined it as such, the presence of arm withdrawal indicates a nonpurposeful movement, which is a spinal level reflex, and is clearly not conscious sedation if appropriate responses are not present to verbal or gentle stimulation. In our study, IV catheter cannulation was attempted only when the child had no appropriate response to verbal or gentle physical stimulation, thereby excluding a state of conscious sedation (even purposeful movement to IV insertion would be consistent with a state of deep sedation). The response to IV insertion was used to differentiate deep sedation from general anesthesia. Anghelescu and Kaplan question our high incidence of deep sedation despite the lack of complications relating to loss of protective airway reflexes (i.e., desaturation). However, these definitions are reflective of states of consciousness, not of the condition of the airway (although loss of protective airway reflexes may result from drugs that cause deep sedation). Respiratory depression is not a sine qua non of the definition of deep sedation. That deep sedation indicates only the potential for airway compromise is clearly substantiated by experts in pediatric anesthesia [3,4], even by Kaplan himself [5]. Furthermore, it is obvious that deep sedation does not necessarily include the loss of protective reflexes when one considers that children undergoing surgical procedures under general anesthesia often maintain spontaneous ventilation and airway patency without oxyhemoglobin desaturation. To substantiate their disbelief of our high incidence of deep sedation, Anghelescu and Kaplan cite studies by Malis and Burton [6] and Napoli et al. [7] as evidence that chloral hydrate has minimal side effects and respiratory depression. The study by Malis and Burton, however, was a retrospective questionnaire study that did not examine respiratory depression. Napoli et al.'s study included children with Down syndrome and known or suspected congenital heart disease (our patients were healthy) and found that 24 (6%) of 397 children sedated with chloral hydrate had oxyhemoglobin saturations that decreased by >5%; 20 of those 24 required airway assistance. This is hardly a testimony to the safety of chloral hydrate. Our study was specifically designed to examine the effect of the addition of nitrous oxide to chloral hydrate sedation. Although we found that the addition of nitrous oxide resulted in hypoventilation, no child developed clinically important airway obstruction or hypoxemia. Thus, we proved that deep sedation is, in fact, possible without airway obstruction, but practitioners should realize that the potential for this dangerous complication exists whenever a child loses consciousness. Ronald S. Litman, DO Robert J. Berkowitz, DDS Denham S. Ward, MD, PhD Strong Memorial Hospital; University of Rochester School of Medicine and Dentistry; Rochester, NY 14642