Anemia of Prematurity - Portal Neonatal

The relative potency of each volatile anesthetic agent is measured in terms of the minimum alveolar
concentration (MAC) of an inhaled anesthetic agent at which 50% of patients do not have skeletal
muscle movement in response to surgical incision or another noxious stimulus. The patient's age
appears to influence the MAC of a given volatile anesthetic, and MAC is higher in infants than in any
other age group. MAC may be 15-25% lower in neonates than in infants and is even lower in premature
neonates. Volatile anesthetic agents are potent myocardial depressants and vasodilators.
Consequently, systolic blood pressure and mean arterial blood pressure may decrease when these
agents are administered. In some neonates, other analgesic agents may be used to decrease volatile
anesthetic agent requirements intraoperatively, thereby avoiding some of the hemodynamic changes
that may occur with volatile anesthetic administration.
In fact, surgical anesthesia can be accomplished without the use of any volatile anesthetic agents.
Narcotics are not complete anesthetic agents; they do not provide muscle relaxation or amnesia, which
are essential functions of complete anesthetics. However, they are potent analgesic medications.
Administration of these agents intraoperatively may be associated with less of a decrease in blood
pressure in neonates than might occur with volatile anesthetic administration. Furthermore, narcotics
are useful adjuncts to anesthetics based on volatile agents because they can reduce the volatile agent
requirement, thereby reducing any hemodynamic lability. Narcotic-based anesthetics are commonly
used during cardiovascular procedures in neonates.
Physicians should note that the pharmacokinetics of narcotics administered to neonates differs from
that of older infants, children, and adolescents. Neonates have a lower clearance, greater volume of
distribution, longer elimination half-life, and higher plasma concentration after narcotic boluses than
older patients. Consequently, the postoperative disposition of neonates may be affected when narcotics
are used intraoperatively. Narcotics commonly used for intraoperative analgesia in neonates include
morphine, fentanyl, sufentanil, and remifentanil.
Ketamine, a phencyclidine derivative, produces amnesia and intense analgesia. This drug affects
opioid receptors and N-methyl-D-aspartate (NDMA) receptors, as well as voltage-sensitive calcium ion
channels as it induces its analgesic effects. Ketamine actually stimulates the cardiovascular system
and thus is frequently associated with increases in both systolic and mean arterial blood pressure, as
well as heart rate, when administered intraoperatively. While ketamine may not be associated with
increased blood pressure in preterm neonates, it is certainly associated with smaller decreases in mean
arterial pressure and systolic blood pressure than the other analgesic medications commonly used
intraoperatively. Beneficial effects of ketamine include production of bronchodilation and less
depression of ventilation. Adverse effects that may occur in neonates include increased salivary and
tracheobronchial secretion production, cerebral vasodilation, and apnea in neonates with increased
intracranial pressure.
POSTOPERATIVE PAIN ASSESSMENT IN NEONATES Section 6 of 10
One factor that has contributed to inadequate pain management in neonates has been the pervasive
belief that neonates do not feel pain. This misconception has been perpetuated, at least in part, by the
conspicuous absence of adequate tools to assess pain levels in this patient population. To a large
extent, pain assessment in older patients relies upon the patient's ability to report pain level in some
form to the caregiver. When patients cannot express pain verbally, pain assessment depends more on
evaluations by the caregiver. Even when pain is evident, quantifying the pain level is not easy. An
effective pain assessment tool must be able to objectively quantify the pain level of the patient so that
the healthcare provider can accurately measure the effectiveness of interventions designed to alleviate
unnecessary suffering. Although no perfect tool exists yet for assessing pain in neonates, infants, and
preverbal children, several very useful tools are available.
The Children's Hospital of Eastern Ontario Pain Scale (CHEOPS) was one of the first observational
pain scales. This tool includes the categories of (1) cry, (2) facial expression, (3) verbal response, (4)
torso position, (5) leg activity, and (6) arm movement in relationship to the surgical wound. In general,