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Biomedical subjects

M J Maisels

Publications and source records attributed to M J Maisels.

At least 19 recordsLinked to original sources

A clinical trial of fiberoptic phototherapy vs conventional phototherapy.

We conducted a randomized, controlled trial to compare fiberoptic phototherapy with conventional phototherapy in healthy jaundiced newborns with birth weights greater than 2500 g. Twelve patients received fiberoptic phototherapy and 14 patients received conventional phototherapy. There were no significant differences between the groups with respect to birth weight, gestational age, feeding method, presence of hemolytic disease, hematocrit, reticulocyte count, or initial serum bilirubin level. Measured irradiance at 425 to 475 nm for conventional phototherapy was greater than that of fiberoptic phototherapy (9.2 +/- 0.9 microW/cm2 per nanometer vs 8.2 +/- 1.2 microW/cm2 per nanometer). Both types of phototherapy lowered the level of serum bilirubin after 18 hours of therapy (fiberoptic group, from 231 +/- 29 to 210 +/- 24 mumol/L; conventional group, from 231 +/- 21 to 188 +/- 26 mumol/L), but the mean serum bilirubin level was lower after 18 hours of therapy in the conventional phototherapy group (188 +/- 26 vs 210 +/- 24 mumol/L). There were no side effects in either group of newborns. Both methods of phototherapy decreased the serum bilirubin level, but conventional phototherapy did so more effectively, probably because of its greater irradiance.

Female

Severe retinopathy of prematurity and steroid exposure.

During a 3-year period (1988 through 1990) an increase was observed in the number of infants born at 23- to 26-weeks' gestation who required cryotherapy for severe retinopathy of prematurity (0/20, 1988; 3/14, 1989; 6/18, 1990; P = .015). Inasmuch as this was not related to improved survival, a retrospective case-control study was conducted to try to explain this observation. Of 52 surviving infants who had been born at 23 to 26 weeks' gestation, 9 required cryotherapy and the other 43 served as control subjects. There were no differences between groups in birthweight, gestational age, or the number of infants with hyaline membrane disease, intraventricular hemorrhage, or hydrocephalus. Factors related to the need for cryotherapy included patent ductus arteriosus (P = .046), mechanical ventilation for more than 21 days (P = .045), and the use of steroids for lung disease (P < .001). In this neonatal intensive care unit, steroids are administered according to the attending neonatologist's preference. Inasmuch as steroids are considered only for infants still ventilator dependent at 21 days, this group was analyzed separately (n = 36). Of the 21 factors examined, only the use of steroids for lung disease was associated with the need for cryotherapy (P < .001).

Case-Control Studies

Double versus single phototherapy in low birth weight newborns.

Conventional phototherapy systems that simultaneously irradiate the front and the back of the baby lower the serum bilirubin level more rapidly than one-sided systems, but they are impractical. Fiberoptic phototherapy makes it easy to administer conventional phototherapy from above while the infant lies on a fiberoptic phototherapy blanket. Newborns with birth weights less than 2500 g were randomly assigned to receive either single (n = 37) or double (n = 33) phototherapy. The groups were similar in clinical and laboratory characteristics. After 18 hours of therapy the serum bilirubin concentration declined by 31 +/- 11% in the double and 16 +/- 15% in the single phototherapy group (2.9 +/- 1.1 vs 1.6 +/- 1.4 mg/dL), and the difference in the total serum bilirubin levels after 18 hours of therapy was significant (double phototherapy group 7.1 +/- 2.7 mg/dL vs single phototherapy group 8.2 +/- 2.6 mg/dL). After 18 hours of treatment the serum bilirubin level was less than the phototherapy threshold level in 26 of 37 single phototherapy patients vs 32 of 33 double phototherapy patients. Double phototherapy was well tolerated. It is concluded that this type of double phototherapy is more effective than single phototherapy in low birth weight newborns. Double phototherapy may be useful when it is necessary to reduce an elevated serum bilirubin level as rapidly as possible or when the bilirubin level is rising with single phototherapy.

Female

Risk of sepsis in newborns with severe hyperbilirubinemia.

Because bacterial infection is a potential cause of hyperbilirubinemia, some authors suggest that newborns with significant unexplained indirect hyperbilirubinemia should be evaluated for sepsis. We reviewed the charts of 306 newborns admitted to a pediatric ward within 21 days of birth with a diagnosis of indirect hyperbilirubinemia (peak serum bilirubin level 316 +/- 48, range 217 to 498 mumol/L) (18.5 +/- 2.8, 12.7 to 29.1 mg/dL). Ninety percent were fully or partially breast-fed. Sepsis was identified in 0 of 306 newborns (upper 95% confidence limit for the risk of sepsis = 1%). The overwhelming majority of newborns who require readmission to hospital for indirect hyperbilirubinemia are healthy, breast-fed newborns and do not need to be investigated for sepsis. If indirect hyperbilirubinemia is ever the only manifestation of bacteremia or incipient sepsis, it must be a rare event.

Bacterial Infections

Evaluation and treatment of jaundice in the term newborn: a kinder, gentler approach.

Standard recommendations for evaluating and treating jaundice in term babies include following all babies closely for jaundice, obtaining several laboratory tests in those with early jaundice or bilirubin levels more than 12 to 13 mg/dL (205 to 222 mumol/L), using phototherapy to try to keep bilirubin levels below 20 mg/dL (342 mumol/L), and doing exchange transfusions if phototherapy fails, regardless of the cause of the jaundice. These recommendations are likely to lead to unnecessary testing and treatment of many jaundiced term infants. Because most jaundiced infants have no underlying illness, and the generally recommended laboratory tests lack sensitivity and specificity, they are seldom useful. In most babies, the only blood tests needed to evaluate jaundice are the blood type and group (of baby and mother) and a direct Coombs' test. A determination of direct bilirubin level should be added if jaundice is prolonged (greater than 2 to 4 weeks) or the baby has other signs of illness. Bilirubin toxicity is rare in term babies without hemolysis. In this low-risk group, the risks and cost of identifying and treating high bilirubin levels may exceed the benefits. Such infants need not be closely followed for jaundice. If significant jaundice is nonetheless found, treatment should be deferred to relatively high levels of serum bilirubin, with a goal of keeping bilirubin levels below 400 to 500 mumol/L (23.4 to 29.2 mg/dL). Babies with hemolytic disease should be followed more closely, and their bilirubin levels kept below 300 to 400 mumol/L (17.5 to 23.4 mg/dL). These recommendations should be reevaluated as new data become available. In the meantime, currently available data justify an approach to the jaundiced term infant that is less aggressive than previously recommended.

Bilirubin

Does hyperbilirubinemia damage the brain of healthy full-term infants?

In the 1950s, exchange transfusion to keep the total serum bilirubin below 20 mg/dl was shown to be an effective way of preventing kernicterus in babies with erythroblastosis fetalis. For the last 15 to 20 years this level has also been used to determine the need for intervention in healthy full-term infants who do not have hemolytic disease. A critical review of all the available data including six studies from the collaborative perinatal project (more than 30,000 infants) and several smaller studies of term infants without hemolysis reveals essentially no evidence of adverse effects of bilirubin on IQ, neurologic examination, or hearing. The investigation and treatment of normal infants with jaundice is expensive and potentially harmful. We need to reassess our approach to hyperbilirubinemia in healthy full-term infants.

Bilirubin

Gastroesophageal reflux to the proximal esophagus in infants with bronchopulmonary dysplasia.

Recurrent aspiration after gastroesophageal reflux (GER) may contribute to the severity of chronic lung disease. If so, it should be possible to document acid reflux to the proximal esophagus. Using an esophageal pH probe placed at the level of the first or second thoracic vertebra, we evaluated GER in 14 infants with bronchopulmonary dysplasia (BPD) and 13 infants without BPD. The infants with BPD had significantly less GER, as measured by the percentage of time the pH was less than 4 (3.26% +/- 7.05% vs 12.88% +/- 15.27% [mean +/- SD]), number of GER episodes per hour (0.46 +/- 0.66 vs 1.35 +/- 0.83), number of GER episodes lasting longer than 5 minutes per hour (0.10 +/- 0.23 vs 0.31 +/- 0.29), and longest GER episode (6.76 +/- 10.29 vs 26.66 +/- 38.30 minutes). Gastroesophageal reflux may be unimportant in infants with BPD, or even occasional episodes of GER may aggravate existing lung disease.

Bronchopulmonary Dysplasia

Regulation of oxygen concentration delivered to infants via nasal cannulas.

The administration of oxygen to infants via nasal cannulas is now a common practice in neonatal units although the inspired oxygen concentration reaching the patient's airway is unknown. We measured the hypopharyngeal oxygen concentration in 10 infants who were receiving oxygen via nasal cannulas and assessed the impact of changes in the flow rate and inspired oxygen concentration. Weaning these infants by reducing the flow rate, even if changes are slight, produces clinically important changes in the oxygen concentration reaching the airway. Such changes are poorly tolerated by infants with chronic lung disease. Changing the flow rate and inspired oxygen concentration, rather than the flow rate alone, provides greater precision and is likely to avoid excessive and abrupt changes in the oxygen concentration reaching the airway.

Administration, Intranasal

Caffeine pharmacokinetics in preterm infants older than 2 weeks.

We studied 17 preterm infants receiving caffeine, and measured their plasma levels of caffeine and the theophylline metabolite by high-pressure liquid chromatography. The half-life was calculated by computer analysis using the least-square method. The mean gestational age of our patients was 29.7 +/- 1.9 weeks (mean +/- SD) and they were studied at 20.7 +/- 6.6 days (mean +/- SD) postnatal age. The caffeine half-life was 52.03 +/- 23.87 h (means +/- SD) and the theophylline half-life was 77.04 +/- 65.01 h (mean +/- SD).

Caffeine

Preductal and postductal transcutaneous oxygen tension measurements in premature newborns with hyaline membrane disease.

Pre- and postductal transcutaneous oxygen tension (tcPO2) was measured in 23 preterm infants with hyaline membrane disease to estimate the degree of right to left ductal shunting. The study was done during the first 24 hours of life and the data were recorded continuously. The studies were 11.9 +/- 4.0- hours long, (mean +/- SD) and the difference between the pre- and postductal tcPO2 (delta TcPO2) was measured every 100 seconds. Of 9,872 determinations, the delta tcPO2 was less than or equal to 15 mm Hg in 90.1%, 16 to 29 mm Hg in 9.3%, and greater than or equal to 30 mm Hg in 0.6%. It was concluded that large differences between pre- and postductal oxygen tension are rare in infants with hyaline membrane disease. The results of this and other published data suggest that it is unlikely that measurement of PaO2 in the descending aorta or tcPO2 below the ductus places infants at an increased risk of having retinopathy of prematurity develop.

Blood Gas Monitoring, Transcutaneous

Jaundice in the healthy newborn infant: a new approach to an old problem.

We measured the serum bilirubin concentrations in 2,416 consecutive infants admitted to our well baby nursery. The maximal serum bilirubin concentration exceeded 12.9 mg/dL (221 mumol/L) in 147 infants (6.1%), and these infants were compared with 147 randomly selected control infants with maximal serum bilirubin levels less than or equal to 12.9 mg/dL. A serum bilirubin concentration greater than 12.9 mg/dL was associated strongly with breast-feeding (P = .0000) and percentage of weight loss after birth (P = .0001), as well as with maternal diabetes, oriental race, decreased gestational age, male sex, bruising, and induction of labor with oxytocin. Risk ratios and the risk of jaundice were calculated for hypothetical infants in the presence and absence of these variables. These calculations show that, in certain infants, "nonphysiologic" jaundice is likely to develop and its presence in such infants might not require laboratory investigations. In others, a modest degree of hyperbilirubinemia could be cause for concern. An awareness of these factors and their potential contribution to serum bilirubin levels permits a more rational approach to the action levels used for the investigation of jaundice in the newborn. We need a new definition of physiologic jaundice.

Bilirubin

Incidence and severity of intraventricular hemorrhage: 1981-1984.

We have examined the trend in the incidence and mortality of intraventricular hemorrhage (IVH) in low birthweight infants from 1981 through 1984. During this time we admitted 407 infants in the first week of life with a birthweight less than or equal to 1500 gm in whom a cranial ultrasonogram or autopsy had been performed. Though the mean birthweight and gestational age, proportion of infants who were inborn, and percentage of infants requiring mechanical ventilation did not change over the 4 years, cesarean deliveries were performed more frequently (P less than .001). The overall incidence of IVH was 62% in 1981, 56% in 1982, 49% in 1983, and 58% in 1984, thus no significant trend was evident. Although the incidence of minor hemorrhages (grades I and II) remained relatively constant, there was a decrease in the incidence of grade III IVH (1981, 11%; 1984, 2%, P = .01). The incidence of grade IV hemorrhage did not change during the 4 years and ranged from 7 to 9%. Mortality rate for all infants weighing less than or equal to 1500 gm and for infants with a minor hemorrhage remained unchanged; however, the mortality rate for infants with a major hemorrhage (grade III or IV) tended to decrease (P = .07). We conclude that although some minor changes in the incidence and mortality have occurred, IVH continues to be a major problem in very-low-birthweight infants at our institution.

Birth Weight