76: Sedation and Analgesia

I. PROBLEM

An infant with pulmonary hypertension with extreme lability needs sedation. Should the infant be sedated, and which agent is available to use? An infant is having a bedside procedure. Should I use a local anesthetic?

II. IMMEDIATE QUESTIONS

1. What is the indication for the sedation? Agitation and movement by the infant during procedures such as extracorporeal membrane oxygenation/extracorporeal life support (ECMO/ECLS) can risk injury. Certain procedures (eg, magnetic resonance imaging [MRI]) mandate that the infant be immobilized, so sedation may be required. Infants with extreme lability on mechanical ventilation may benefit from sedation.

2. Why does the infant need analgesia? If the newborn is to undergo minor procedures such as elective circumcision, local anesthesia is usually administered. For emergency procedures such as chest tube placement, the need for analgesia must be weighed against the delay of administering the analgesic agent.

3. If treating for agitation while an infant is on mechanical ventilation, is the infant adequately ventilated? Hypoxia and inadequate ventilation can result in agitation, and sedation is dangerous in these situations.

4. Is sedation needed for a short period (ie, for a diagnostic procedure) or long term? Certain medications are indicated for short-term sedation (ie, chloral hydrate) and should not be used long term.

III. DIFFERENTIAL DIAGNOSIS AND INDICATIONS

1. Indications for analgesia. Whether a newborn can experience pain remains in the philosophical realm, but they undeniably react to painful stimuli (nociception). Such stimuli elicit both clinical symptoms (eg, tachycardia, hypertension, and decreased oxygenation) and complex behavioral responses in term and preterm infants. By 23 weeks' gestation, the nervous system has developed sufficiently to enable the conduction of nociceptive stimuli from peripheral skin receptors to the brain. The development of the descending inhibiting pathways occurs at a later stage; therefore, the more immature infant may have an even lower threshold for noxious stimulus than at a later age. Neonates possibly have an increased sensitivity to pain compared with older age groups. During surgical interventions, the neonate, like the adult, mounts a hormonal response that consists of the release of catecholamines, β-endorphins, corticotropin, growth hormone, and glucagon as well as the suppression of insulin secretion. This response is reduced by prior administration of analgesia or anesthesia. Although we do not know whether or not the neonate experiences psychological distress and lasting psychological sequelae, there are enough reasons to attempt to control exposure to pain as well as other unpleasant experiences.

   1. Major surgical procedures such as ligation of the ductus arteriosus or laparotomy require major anesthesia. General anesthesia should be provided by inhalation of anesthetic gases or intravenous (IV) administration of narcotic agents. In all these conditions, the use of paralytic agents without analgesia is absolutely contraindicated.

   2. Postoperative management

      1. Narcotic agents should always be included in the immediate postoperative period. Supplementary sedation is often provided by benzodiazepines or chloral hydrate, which are useful to combat agitation and potentiate the ...