Methylxanthine use for apnea of prematurity among an international cohort of neonatologists

BACKGROUND

A recent multinational clinical trial in preterm infants has demonstrated pulmonary and neurodevelopmental benefits from caffeine therapy. Indications for caffeine use in that study were predominantly for treatment of apnea and facilitation of extubation rather than prophylaxis. There are no recent studies that describe current practice of neonatologists and regional differences in regards to indications for starting, monitoring and discontinuing methylxanthine therapy in premature infants.

OBJECTIVE

To characterize the spectrum of current practice and demonstrate the extent to which methylxanthine therapy varies by location.

METHODS

A cross-sectional survey of all neonatologists in Thailand, Lebanon, Australia, and a representative sample in the USA regarding management of apnea of prematurity.

RESULTS

The response rate was 50% (342/681). The methylxanthine of choice varied greatly across study locations. Prophylactic methylxanthine use is common (62%) among neonatologists in all four study locations. Significant variation exists in almost all aspects of apnea pharmacotherapy practice among neonatologists in different international locations.

CONCLUSIONS

Prophylactic use of methylxanthine therapy for apnea of prematurity is widespread. We speculate that this expanded use is possibly attributed to the beneficial effects of caffeine therapy in the Caffeine for Apnea of Prematurity (CAP) Trial.

Effect of narghile and cigarette smoking on newborn birthweight

OBJECTIVE

To assess the effect of narghile smoking on the weight of newborns.

DESIGN

Historical retrospective cohort.

SETTING

Six major hospitals in Greater Beirut, Lebanon.

POPULATION

Consecutive singleton newborns delivered from August 2000 to August 2003.

METHODS

Obstetric and nursery charts were reviewed to obtain information about maternal and neonatal variables. Information concerning initiation of smoking, dose of smoking, smoking habits during pregnancy, and socio-demographic characteristics was collected through interviews with mothers.

MAIN OUTCOME MEASURES

Low birthweight and newborn birthweight.

RESULTS

Exclusive narghile smokers constituted 4.4% (378/8592) of women. Multiparas were significantly more likely to smoke cigarettes and narghile. Mothers smoking narghile more than once per day were at 2.4 increased odds of having low birthweight infants compared with nonsmoking mothers (OR 2.4; 95% CI 1.2-5.0) after adjusting for confounding variables. No difference was noted between women smoking narghile in the first trimester and those initiating smoking in subsequent trimesters regarding low birthweight.

CONCLUSIONS

Narghile smoking more than once per day increases the odds of low birthweight by a 2.4-fold compared with nonsmokers, although to a lesser extent than cigarette smoking.

Household crowding index: a correlate of socioeconomic status and inter-pregnancy spacing in an urban setting

OBJECTIVES

This paper examines the effect of household crowding on inter-pregnancy spacing and its association with socioeconomic indicators, among parous mothers delivered in an urban environment.

DESIGN

Cross sectional survey.

METHODS

Sociodemographic data were obtained on 2466 parous women delivering at eight hospitals in Greater Beirut over a one year period. Statistical methodology comprised Pearson chi(2) test and logistic regression analysis.

MAIN RESULTS

A significant inverse relation was observed between household crowding and socioeconomic status, defined as education and occupation of women and their spouses. Inter-pregnancy spacing increased with higher levels of crowding. Further analysis suggested that this positive association was confounded by maternal demographic characteristics.

CONCLUSIONS

These data have shown that household crowding, a correlate of low parental socioeconomic status, is associated with longer birth intervals. This association, however, seems to be largely explained by maternal age and parity.

False-negative primary neonatal thyroid screening: the need for clinical vigilance and secondary screening

The screening of newborn babies for congenital hypothyroidism has changed the natural history of this abnormality. We describe here a case of a female patient with congenital hypothyroidism that was missed by primary neonatal thyroid screening (using thyroid-stimulating hormone) at two days of age; it was detected only after the development and persistence of jaundice during the first three weeks of life. A normal neonatal screening result does not preclude the development of hypothyroidism later in infancy. Clinical vigilance must be maintained by practitioners. A second screening between two and six weeks of age may be useful in order to detect the few cases missed at first screening.

High frequency ventilation

High frequency ventilation (HFV) is a general term that refers to a family of mechanical ventilation techniques that involves ventilator rates that are supraphysiological (more than 60 breaths/minute), and utilizes tidal volumes that are equal or less than the anatomical dead space of the airways. This paper is a review of the different HFV techniques, along with the mechanisms of oxygenation and ventilation, the clinical applications, and management strategies for different disease entities, and possible complications of HFV.

High frequency ventilation in five different neonatal pathologies

High frequency ventilation (HFV) has been used for the last two decades. Several questions related to its optimal use, comparative efficacy of different types of HFV, as well as the role of HFV in different diseases are still debated and under investigation. Literature reviews discussing the controversies in high frequency ventilation have rather emphasized the importance of a disease strategy rather then the type of HFV. In this article, a presentation and discussion of five patients with different HFV strategies admitted and managed with HFV at the American University of Beirut-Medical Center.

Paediatric infective endocarditis: 19-year experience at a tertiary care hospital in a developing country

A retrospective study was undertaken to study children who presented with infective endocarditis (IE) to a university teaching hospital in Beirut, Lebanon, between January 1977 and May 1995. Of 41 patients with IE (24F, 17M), 28 (68%) were diagnosed between 1977 and 1985. Patients' ages ranged from 3 to 18 y (mean age 11.3+/-2.8 y), and 13 patients were <10 y of age. Clinical presentations included: fever (in 88%), heart failure (in 39%), neurologic findings (in 20%) and embolic phenomena (in 22%). Nineteen patients (46%) had underlying congenital heart disease (CHD) with tetralogy of Fallot and pulmonary stenosis being the most common. Sixteen patients (39%) had underlying rheumatic heart disease (RHD). A total of 5 children (12%) with normal cardiac anatomy had IE. One had underlying acquired viral myocarditis with mitral insufficiency. Echocardiography showed vegetations in 60%. Blood cultures were positive in 31 patients (76%). IE occurred in three patients following cardiac surgery. In one patient it occurred within 2 mo of surgery and in the other two it occurred within 6 mo. Streptococcus viridans and Staphylococcus aureus were the two most commonly isolated bacteria. Overall mortality rate was 29% (not statistically significant between patients presenting between 1977-1985 and 1986-1995; p = 0.17). There was no statistically significant difference in mortality among the groups (five in the group with CHD, six with RHD and one with structurally normal heart). This study demonstrates that RHD is an important underlying cause of IE in children in our community. This finding is similar to those in other developing countries and different from those in developed countries. Distribution of pathogens and CHD in our study is comparable to some reports in the literature, except for the higher proportion of patients with underlying pulmonary stenosis. Bacterial endocarditis prophylaxis should be emphasized in patients with RHD or pulmonary stenosis.

Transient hypertrophic cardiomyopathy in the newborn following multiple doses of antenatal corticosteroids

Postnatal exposure to steroids has been associated with hypertrophic cardiomyopathy (HCM) in the newborn. Such an effect has not been described in infants born to mothers who received antenatal steroids. We report three newborns whose mothers were treated with betamethasone prenatally in different doses, duration of time, and who developed various degrees of HCM diagnosed by echocardiography. There was no maternal evidence of diabetes except for one infant whose mother had a normal fasting and post-prandial blood glucose prior to steroid therapy, but an abnormal one hour postprandial glucose after 8 weeks of betamethasone therapy, with a normal HbA1 C level. There was no family history of HCM, no history of maternal intake of other relevant medications, and no hypertension in all three newborns. Follow-up echocardiography revealed complete resolution of the HCM changes in all infants. We suggest that repeated antenatal maternal steroid intake may cause changes of HCM in the newborn. These changes appear to be dose- and duration-related and are mostly reversible. Further prospective controlled studies to evaluate these observations and to investigate potential mechanisms are warranted.

Congenital heart disease at a tertiary care center in Lebanon

OBJECTIVE AND METHODS

To study the epidemiology of congenital heart disease (CHD) at the American University of Beirut-Medical Center, we reviewed the medical records of all cardiac patients seen at our outpatient cardiology clinic (OPD) between 1980 and 1995. The charts of all patients with CHD seen as inpatients and/or outpatients at our center during the year 1995 were also reviewed. A cardiologist evaluated all patients and the diagnosis was confirmed at least by echocardiography. The frequency of CHD was reported among three groups: 1980-1995 OPD groups (Group A); the group with CHD seen during the year 1995 (Group B); and (Group C), a subgroup of group B, included all newborns with CHD born at our hospital during the year 1995. Stillbirth and premature infants with the diagnosis of patent ductus arteriosus were excluded from the study.

RESULTS

Group A included 883 patients. 344 patients were evaluated in Group B, with a mean age of 3.8 years. The incidence of CHD was 11.5/1,000 live births at our center. There was a relatively low prevalence of complex lesions (i.e., hypoplastic left heart syndrome, transposition of the great arteries) and a relatively high prevalence of the simpler cardiac malformation (i.e., ventricular and atrial septal defects, pulmonary stenosis) in Groups A and B.

CONCLUSION

The relatively low prevalence of complex cardiac lesions in our study is probably related to the age of the studied patients, and reflects the high mortality of these complex lesions in our country early in life. The incidence of CHD of 11.5/1,000 live births at our center is higher than that reported in the literature, with evidence of more frequent ventricular septal defects and pulmonary atresia lesions. This may be related to high rate of consanguinity in our population. This review underscores the need for a national cardiac registry center for children in a developing country like Lebanon. Such a database will allow referral and care of complex cardiac lesions.

Glucose kinetics following administration of an intravenous fat emulsion to low-birth-weight neonates

To evaluate the mechanism(s) of the observed increase in plasma glucose concentration following the administration of an intravenous fat emulsion to the neonate, we measured glucose kinetics in eight low-birth-weight neonates by the prime constant rate infusion technique with D-[6,6-2H2]glucose at a rate of 0.22 +/- 0.01 mumol.kg-1 x min-1 (39.4 +/- 1.3 micrograms.kg-1 x min-1) while the neonates received 32 +/- 5 mumol.kg-1 x min-1 glucose (6.3 +/- 1.1 mg.kg-1 x min-1) plus an amino acid mixture (parenteral alimentation) alone and in combination with an intravenous fat emulsion (Intralipid). Following the latter combination, there were significant increases in plasma glucose concentration [4.07 +/- 0.11 (73 +/- 2 mg/dl) to 5.00 +/- 0.22 mmol/l (90 +/- 4 mg/dl); P < 0.01] and in plasma insulin concentration [72 +/- 14 (10 +/- 2 microU/ml) to 172 +/- 36 pmol/l (24 +/- 5 microU/ml); P < 0.05]. The parenteral alimentation and intravenous fat effusion combination did not affect the glucose production rate: 0.15 +/- 0.05 mumol.kg-1 x min-1 (0.03 +/- 0.01 mg.kg-1 x min-1) during the parenteral alimentation alone and 0.16 +/- 0.05 mumol.kg-1 x min-1 (0.03 +/- 0.01 mg.kg-1 x min-1) when parenteral alimentation was combined with an intravenous fat emulsion. We conclude that the increased plasma glucose concentration seen in association with administration of parenteral alimentation combined with an intravenous fat emulsion to the premature neonate is not due to enhanced glucose production but could be the result of alterations in glucose utilization.

Neurodevelopmental and medical status of low-birthweight survivors of bronchopulmonary dysplasia at 10 to 12 years of age

Thirty low-birthweight (less than 1500g) infants (15 with bronchopulmonary dysplasia (BPD), and 15 controls less than or equal to 5 days O2) and 15 fullterm controls were evaluated at 10 to 12 years of age. BPD children weighted less than fullterm children and had smaller head circumferences than either preterm or fullterm controls. They also had significantly more neurological abnormality than both control groups. BPD children and preterm controls had lower WISC-R arithmetic scores and lower Beery VMI scores, as well as greater need of resources and special education compared with fullterm controls. BPD survivors at 10 to 12 years of age continue to manifest sequelae related to their early pulmonary disease.

Effects of intravenous glucose loading on oxygen consumption, carbon dioxide production, and resting energy expenditure in infants with bronchopulmonary dysplasia

To determine the effects of intravenous glucose loading on basal oxygen consumption, resting energy expenditure, and basal carbon dioxide production in infants with bronchopulmonary dysplasia who were still oxygen dependent, we administered intravenous glucose loads of 4 and 12 mg/kg-1/min-1 on 2 consecutive days, under identical experimental conditions, to six infants with bronchopulmonary dysplasia and six healthy control subjects. Infants were not fed for 9 hours before and during the 4- to 6-hour study periods; the intravenous glucose infusion, along with an amino acid mixture (2 gm.kg-1.24 hr-1), was started at the beginning of the fasting period. Oxygen consumption and carbon dioxide production and resting energy expenditure were measured by a flow-through indirect calorimetry technique under basal conditions. Infants with oxygen-dependent bronchopulmonary dysplasia had significantly higher basal oxygen consumption and resting energy expenditure than did control infants and significantly higher basal carbon dioxide production during the high glucose infusion. With glucose loading, infants with bronchopulmonary dysplasia had a significant rise in basal oxygen consumption (7.91 +/- 0.91 ml.kg-1.min-1 to 9.65 +/- 1.35 ml.kg-1.min-1, p less than 0.05), basal carbon dioxide production (5.93 +/- 0.72 ml.kg-1.min-1 to 7.10 +/- 1.04 ml.kg-1.min-1), and resting energy expenditure (53.8 +/- 5.75 kcal.kg-1.24 hr-1 to 65.3 +/- 7.0 kcal.kg-1.24 hr-1, all p values less than 0.05). Control infants had no significant changes with intravenous glucose loading. We conclude that intravenous glucose loading in infants with bronchopulmonary dysplasia resulted in a net increase in resting energy expenditure, which should be taken into account in assessing their energy intake during nutritional management. The risk of pulmonary stress caused by an increase in basal oxygen consumption and carbon dioxide production resulting from glucose load should also be considered.