RESUMO
Opioids have been used for analgesia in nearly all civilizations. In paediatrics their use has become widely accepted for combating severe pain, especially postoperative pain and tumour pain. Receptors in the central nervous system are the best known sites of action of opioids, but the existence of peripheral receptors is also probable. The action depends on whether the opioid is more agonist or antagonist and on the peculiarities of physiology in childhood: in the small child a hyperdynamic blood circulation makes resorption faster, and in newborn and premature infants distribution and excretion are influenced by the different composition of the body and the immaturity of liver and kidney. The best known opioid is morphine, and it is the reference substance with which all other opioids are compared. Fentanyl has been used even for the smallest ventilated prematures in recent times, as it is easy to manage and has an early onset of action. Its depressant action on the respiratory centre is an advantage when attempts of spontaneous breathing make mechanical ventilation difficult. Obstinate constipation is the disadvantage of both morphine and fentanyl, and an exacerbation of hyperbilirubinaemia has been seen with fentanyl. Nalbuphine causes a lower degree of respiratory depression. The newer opioids alfentanil and sufentanil have already been used for the relief of paediatric postoperative pain and during mechanical ventilation, but no special advantages of their use are reported. Meperidine has been favoured especially for postoperative pain, although it appears to have no advantages over morphine. Its active metabolite normeperidine may accumulate and cause seizures; meperidine should not be used in prematures or in children with renal dysfunction. There are few publications on the use of piritramide in paediatric pain. Tramadol is widely used for emergencies, as it has the least sedative action; but it has disadvantages in causing nausea and vomiting. Codeine is widely used for its antitussive action. While the necessity of good analgesia for even the smallest infant cannot be overstated, the opioid used must be carefully selected with reference to the age of the child and the pain to be controlled.
RESUMO
To determine the effects of fentanyl in newborn and premature infants, we compared two groups of 20 newborn and premature babies under artificial ventilation for severe respiratory distress syndrome: a prospective group receiving fentanyl for analgesic and sedation and a historical control group, who did not receive fentanyl. Fentanyl serum levels during steady state were determined by radioimmunoassay. Average time of infusion was 86 +/- 47 h with a mean dosage of 0.68 +/- 0.24 micrograms/kg/h. The fentanyl group needed much less sedatives and catecholamines. Heart rate and blood pressure were not significantly changed by fentanyl. Meconium was excreted later, and higher values of bilirubin were reached earlier than in the control group. Although fentanyl proved to be helpful in the neonatal intensive care unit, the administration should remain under strict indication.
Assuntos
Fentanila/administração & dosagem , Hipnóticos e Sedativos , Recém-Nascido/fisiologia , Recém-Nascido Prematuro/fisiologia , Bilirrubina/sangue , Pressão Sanguínea/efeitos dos fármacos , Feminino , Idade Gestacional , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipnóticos e Sedativos/administração & dosagem , Infusões Intravenosas , Masculino , Respiração ArtificialRESUMO
In pediatric intensive care, analgesia and sedation has become increasingly important for newborns as well as prematures in recent years. However, its importance is frequently not well recognized and sedation is confounded with analgesia. In our intensive-care unit (ICU), fentanyl and midazolam have proved to be useful. In newborn and premature infants, fentanyl alone has been sufficient because of its analgesic and sedative action. In a study on 20 newborns and prematures suffering from severe respiratory problems as compared with a historical group that did not receive fentanyl, we could show that in subjects receiving fentanyl, considerably less treatment with sedatives and other analgesics was necessary. Cardiopulmonary tolerance was satisfactory. The highest bilirubin values were reached about 1 day earlier and were slightly higher than those measured in the control group, but oral nutrition could be initiated sooner. In small infants, additional midazolam was given after cardiac surgery. During the first 72 h, we found a correlation between serum levels of midazolam and the depth of sedation; however, after 72 h of medication, the dose had to be raised because of an increase in metabolic clearance. During the concomitant administration of midazolam and fentanyl, significantly less midazolam was needed to achieve appropriate analog-sedation. Prior to the administration of analgesics and sedatives, care should be taken to ensure that circulatory conditions are stable and that there is no hypovolemia, and the drugs must be given slowly during several minutes. Especially in a pediatric ICU, light and noise should be diminished and contact between the parents and the child should be encouraged, even when the child is undergoing mechanical ventilation.