Newborn, The

Mepivacaine hydrochloride [1722-62-9] similar in profile to Hdocaine, is used for infiltration, peripheral nerve blocks, and extradural anesthesia. It appears to be less toxic than Hdocaine in adults but more toxic in newborns. The duration of action is longer than that of Hdocaine because of its lower vasodilator activity. Mepivacaine has Htde topical activity. 

Congenital hypothyroidism is still seen in the United States, and all newborns in the United States undergo screening with a TSH level. As soon as the hypothyroid state is identified, the newborn should receive the full LT4 replacement dose. The replacement dose of LT4 in children is age-dependent. In newborns, the usual dose is 10 to 17 mcg/kg per day. LT4 tablets may be crushed and mixed with breast milk or formula. Serum FT4 levels (target 1.6-2.2 ng/dL or 20.59-28.31 pmol/L) are used for dose titration in infants because the TSH level may not respond to treatment as it does in older children and adults. By 6 months of age, the required dose is reduced to 5 to 7 mcg/kg per day, and from ages 1 to 10 years, the dose is 3 to 6 mcg/kg per day. After age 12, adult doses can be given. 

Newborns The recommended starting dose is 10 to 15 meg/kg/day. Consider a lower starting dose (eg, 25 mcg/day) in infants at risk for cardiac... 

Toxic reactions including fatalities (approximately 40%) have occurred in the premature infant and newborn the signs and symptoms associated with these reactions have been referred to as the gray syndrome. ... 

Hypoprothrombinemia may occur in malabsorption syndromes and also the use of broad-spectrum antibiotics may produce a hypoprothrombinemia that responds readily to small doses of vitamin K. In premature infants and in infants with hemorrhagic disease of the newborn the use of vitamin K may be indicated. However, the main indication for the use of vitamin K is to antagonize the anticoagulant activity of coumarins. Oral absorption of phytonadione and the menaquinones is by the lymph while menadione and its water-soluble derivatives are absorbed directly. The absorption of phytonadione is energy-dependent and saturable. Intravenous administration of phytonadione has produced flushing, dyspnea, chest pains, and cardiovascular collapse. 

Babies bom to opioid-addicted women also exhibit withdrawal signs, but because of the slower metabolism of opioids in the newborn, the withdrawal signs are more protracted. The babies are often treated with the opium preparation paregoric to reduce withdrawal signs. 

In addition to all of the adverse effects and contraindications previously described for morphine, the following contraindications apply specifically to these drugs. They are contraindicated in pregnant women because of their potential teratogenic effects. They also can cause respiratory depression in the mother, which reduces oxygenation of fetal blood, and in the newborn the incidence of sudden infant death syndrome (SIDS) in the newborn is also increased. 

Sulfonamides compete for sites on plasma proteins that are responsible for the binding of bilirubin. As a result, less bilirubin is bound, and in the newborn, the unbound bilirubin can be deposited in the basal ganglia and subthalamic nuclei, causing kernicterus, a toxic encephalopathy. For this reason, sulfonamides should not be administered to newborns or to women during the last 2 months of pregnancy. 

At birth, term infants can metabolize and eliminate drugs. For most patients these systems did not function during fetal life and therefore even at birth are not very efficient. Table 6.1 outlines the time required for maturation of some of the systems used in drug absorption and elimination. Table 6.2 lists other factors that alter drug disposition in newborns. The ability to absorb and eliminate drugs increases slowly over the first month of life. 

Lysosomal storage diseases are rare, with an estimated birth prevalence of about 1 5000 to 1 7000 newborns. The sphingolipidoses make up about one-half of the total number of patients with lysosomal storage diseases [35, 44, 45]. In some popu-... 

In a disease that is restricted to the newborn, the use of immunoprophylaxis is impractical, due to the time lag before effective levels of... 

Elemental speciation studies show that human milk, especially colostrum and transitional milk, is very rich in HMW species associated with metals. Of course, many more studies are needed for a reliable speciation of such HMW compounds. In this sense, validation approaches, both for the reliable identification and exact determination of such species, should be urgently developed. In the same way as the elemental composition and/or distribution of human milk can be considered ideal for feeding the newborn, the composition of formula milks for newborns should ideally be as similar as possible to maternal milk at every lactating stage. However, essential element speciation in formula milks is far from that of human milk (the ideal composition). This could explain why the bioavailability of essential elements (including Cu, Fe, I, Mn, Se, and Zn) from formula milk is much lower than from human milk. Hence, artificial formulas are usually supplemented with such essential elements. More scientific knowledge is definitely necessary on the composition (speciation) of such elements and more attention must be paid to the chemical form in which they are added to formula milks. 

In about 2% to 4% of full-term newborns, the membrane over the valve of Hasner at the nasal end of the duct has not perforated. This causes a recurrent conjunctivitis and sometimes a dacryocystitis. Because spontaneous opening frequently occurs 1 to 2 months after birth, management is typically not aggressive. Warm compresses, massage from the canaliculi down over the lacrimal sac, and a topical antibiotic, if mucopurulent discharge is present, are usually prescribed for initial treatment (see Table 11-1). 

The incidence of phenylketonuria is about 1 in 20,000 newborns. The disease is inherited in an autosomal recessive manner. Heterozygotes, who make up about 1.5% of a typical population, appear normal. Carriers of the phenylketonuria gene have a reduced level of phenylalanine hydroxylase, as indicated by an increased level of phenylalanine in the blood. However, this criterion is not absolute, because the blood levels of phenylalanine in carriers and normal people overlap to some extent. The measurement of the kinetics of the disappearance of intravenously administered phenylalanine is a more definitive test for the carrier state. It should be noted that a high blood level of phenylalanine in a pregnant woman can result in abnormal development of the fetus. This is a striking example of maternal-fetal relationships at the molecular level. Table 23.3 lists some other diseases of amino acid metabolism. 

The disappearance of xanthurenic acid after pyridoxine dierapy suggested the possibility of a latent Be deficiency (Dl). Dahler-Vollen-weider (D2) screened 159 children in respect to the urinary picture of tryptophan metabolites and found an abnormal excretion of xanthurenic acid in 17, whereas 142 fell within normal limits after tryptophan loading. There seems to be an increased rate of excretion widi age. In the newborn the excretion was the lowest while the maximal values were found in the age group 10-16 years. During periods of rapid growth there was a high excretion rate of xanthurenic acid, which was not appreciably affected by daily oral administration of 100 mg pyridoxine. 

Roberts JD Jr, Fineman JR, Morin FC 3rd, Shaul PW, Rimar S, Schreiber MD, Polin RA, Zwass MS, Zayek MM, Gross I, Heymann MA, Zapol WM. Inhaled nitric oxide and persistent pulmonary hypertension of the newborn. The Inhaled Nitric Oxide Study Group. N Engl J Med 1997 336(9) 605-10. 

There is placental transfer of vecuronium, but no effects have been detected in the newborn (the feto-maternal concentration ratio is about 10% less than for pancuronium (31). Postpartum, vecuronium has been reported to have an appreciably longer duration of action (SEDA-13, 105) (32,33) when given in a dose of 0.1 mg/kg. 

Airway VIP content has also been measured in patients with the respiratory distress syndrome of the newborn. The VIP content of airways of children who died of acute respiratory distress syndrome did not differ from that of airways of age-matched control children who died of non-respiratory causes (Ghatei et al., 1983). 

Research performed by Charles DiMarzio s students [29] at Northeastern University is on the study of blood oxygenation. For the first application, a fiber optic device has been built to measure blood oxygen in the brain. A NIR beam is shone on the patient s head at one point via a fiber optic probe, and a second probe is used to collect the energy from a second point. This technique is expected to be useful in brain surgery in newborns. The other application for a noninvasive NIR probe is for use in measuring oxygen levels in the skin. This second device would be useful for patients with bums, skin ulcers, and other skin problems. 

Vest, M.F. Rossier, R. (1963) Detoxification in the newborn the ability of the newborn infant to form conjugates with glucuronic acid, glycine, acetate and glutathione. Annals of the New York Academy of Sciences, 111, 183-197. 

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