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Osteopenia, a condition characterised by a reduction in bone mineral content, is a common disease of preterm babies between the tenth and sixteenth week of life. Prematurely born infants are deprived of the intrauterine supply of minerals affecting bone mineralization.The aetiology is multifactorial: inadequate nutrients intake (calcium, phosphorus and vitamin D), a prolonged period of total parenteral nutrition, immobilisation and the intake of some drugs.The diagnosis of metabolic bone disease is done by biochemical analysis: low serum levels of phosphorus and high levels of alkaline phosphatase are suggestive of metabolic bone disease. The disease can remain clinically silent or presents with symptoms and signs of rachitism depending on the severity of bone demineralisation.An early nutritional intervention can reduce both the prevalence and the severity of osteopenia.This article reviews the pathophysiology of foetal and neonatal bone metabolism, focuses on the nutrient requirements of premature babies and on the ways to early detect and treat osteopenia.

ABSTRACT:The study of respiratory mechanics in infants requires a noninvasive accurate measurement of the lung volume changes (⌬V L ). Optoelectronic plethysmography (OEP) allows the assessment of ⌬V L through the measurement of the chest wall surface motion and it has been proved to be accurate in adults. The aim of this study was to apply OEP to newborns and to validate it by comparison to pneumotachography. Twenty term and preterm newborns (GA ϭ 34 Ϯ 5 wk) in stable condition were studied during 1 to 2 min periods of quiet breathing in supine position. Airway opening flow was measured by applying a facemask connected to a pneumotachograph (PNT) and integrated to provide the ⌬V L . Chest wall volume changes were simultaneously measured by OEP. The tidal volume values measured by pneumotachography and by OEP were compared for each breath. A total of 771 breaths from all patients were considered. Bland-Altmann analysis showed a mean difference of Ϫ0.08 mL and a limit of agreement ranging from Ϫ2.98 to 2.83 mL. Linear regression analysis demonstrated good correlation between the two techniques (r 2 ϭ 0.95, q ϭ 1.00 mL, m ϭ 0.96). OEP provides accurate measurements of ⌬V L in newborns and may be useful to study respiratory mechanics and breathing patterns during spontaneous breathing and mechanical ventilation. T he study of respiratory mechanics and control of breathing ideally requires an accurate and noninvasive measurement of lung volume changes (⌬V L ) not interfering with patients' spontaneous activity. Unfortunately, the currently available methods for the measurement of ⌬V L in infants present several intrinsic and unresolved limitations.Most of the techniques require either connections to the airway opening or critical patient-and posture-dependent calibration procedures. Connecting to the airway opening may introduce leaks, annoy the infant, and affect the breathing pattern (1,2), while the use of patient-dependent calibration procedures can lead to inaccurate measurements when a patient's condition or posture changes with respect to the baseline state (3). Moreover, none of the existing techniques have proved to be reliable in tracking long-term changes in endexpiratory lung volume (EELV) due to integration drift or problems in the measurements stability (4,5).Optoelectronic plethysmography (OEP) is a noninvasive technique, which estimates chest wall volume (V CW ) by measuring the three-dimensional position of several reflective markers placed on the patient's thorax (6 -8). This technique has proved to be reliable in adults in different postures and conditions (7,8).OEP does not require a connection to the airway opening or subject-specific calibration procedures. It provides an accurate measurement of the V CW and it allows, through the use of subsets of the markers placed on the thorax, the measurement of separate compartments, such as the rib cage, abdomen, or smaller components (9). Being based on the direct measurement of chest wall volumes, OEP is not affected by integration drift and can be use...

Background: The role of nasal continuous positive airways pressure (nCPAP) in the management of respiratory distress syndrome in preterm infants is not completely defined. Objective: To evaluate the benefits and risks of prophylactic nCPAP in infants of 28-31 weeks gestation. Design: Multicentre randomised controlled clinical trial. Setting: Seventeen Italian neonatal intensive care units. Patients: A total of 230 newborns of 28-31 weeks gestation, not intubated in the delivery room and without major malformations, were randomly assigned to prophylactic or rescue nCPAP. Interventions: Prophylactic nCPAP was started within 30 minutes of birth, irrespective of oxygen requirement and clinical status. Rescue nCPAP was started when FIO 2 requirement was . 0.4, for more than 30 minutes, to maintain transcutaneous oxygen saturation between 93% and 96%. Exogenous surfactant was given when FIO 2 requirement was . 0.4 in nCPAP in the presence of radiological signs of respiratory distress syndrome. Main outcome measures: Primary end point: need for exogenous surfactant. Secondary end points: need for mechanical ventilation and incidence of air leaks. Results: Surfactant was needed by 22.6% in the prophylaxis group and 21.7% in the rescue group. Mechanical ventilation was required by 12.2% in both the prophylaxis and rescue group. The incidence of air leaks was 2.6% in both groups. More than 80% of both groups had received prenatal steroids. Conclusions: In newborns of 28-31 weeks gestation, there is no greater benefit in giving prophylactic nCPAP than in starting nCPAP when the oxygen requirement increases to a FIO 2 . 0.4.

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