Theoretically, the beneficial effect of dobutamine is due to its essential adrenergic action.
Aim: To study baroreflex maturation by measuring, longitudinally, baroreflex sensitivity in preterm (gestational age 24-37 weeks) and full term infants. Methods: Baroreflex sensitivity was quantified once a week, one to seven times, by a totally non-invasive method. Results: Baroreflex sensitivity at birth was lower in the preterm infant and increased with gestational age. It also increased with postnatal age, but the values for the preterm infants at term still tended to be lower than the values for full term babies. Conclusion: Baroreflex control of heart rate is present in the premature infant, but is underdeveloped and increases with postnatal age. Ex utero maturation seems to be delayed compared with in utero maturation assessed by full term values. These results may reflect sympathovagal imbalance in preterm infants and could identify a population more vulnerable to stress.T he short term regulation of arterial blood pressure by the autonomic nervous system involves the arterial baroreflex. This reflex minimises any variation in blood pressure by responses of both heart rate and arterial vascular tone. For example, an increase in blood pressure will be buffered by a decrease in both heart rate and peripheral vascular resistance. These responses of heart rate and vascular resistance, produced by the efferent limb of the baroreflex, are mediated by the parasympathetic and sympathetic system respectively. As both systems are involved, studies on the baroreflex give information on sympathovagal balance.Our knowledge about ontogeny of the baroreflex relies almost exclusively on animal studies, performed mainly in the lamb. Shinebourne et al 1 have shown the presence of functional arterial baroreflex responses in sheep very early during fetal and postnatal life. Furthermore, these authors and others 2 have shown that the arterial baroreflex is impaired in the fetus and newborn and increases later. Others have found, however, that the sensitivity of baroreflex control of the heart rate does not change throughout gestation 3 or is higher during fetal life than postnatally. 4 Few studies in humans have investigated the development of the baroreflex, possibly because the classical methods of investigation were not applicable to newborns for ethical reasons.The classical methods of investigating baroreflex sensitivity (BRS) are based on analysis of changes in blood pressure and heart rate experimentally induced in a controlled fashion by various manoeuvres. In these methods, the change in blood pressure is produced by either pharmacological or mechanical means. The pharmacological methods consist of giving vasoactive drugs, such as phenylephrine and nitroprusside, whereas the mechanical methods consist of carotid baroreceptor deactivation or stimulation by body tilting or use of a neck chamber device. However, these methods have major limitations. Firstly, they are not very physiological and thus cannot be easily repeated many times over a short period. As a consequence, they cannot be used to provide information on ...
Procalcitonin (PCT) and C reactive protein (CRP) concentrations in umbilical cord blood of 197 neonates were measured to evaluate their value as markers of infection. Sixteen of the neonates were infected. The sensitivity, specificity, and negative and positive predictive values were respectively 87.5%, 98.7%, 87.5%, and 98.7% for PCT and 50%, 97%, 67%, and 94% for CRP. Serum PCT in cord blood seems to be a useful and early marker of antenatal infection.M aternofetal bacterial infection is one of the most common causes of neonatal morbidity and mortality. Early diagnosis and treatment are vital to improve outcome. In the absence of reliable infection markers during the first hours of life, paediatricians often start early antibiotic treatment in newborn infants with risk factors for infection, exposing a considerable number of patients to unnecessary treatment. Procalcitonin (PCT) has been implicated as a sensitive and specific marker of bacterial infection. 2However, it is well established that PCT concentrations in the neonate show a physiological increase during the first two days of life, which complicates the interpretation of results during this period. 3 The aim of this study was to evaluate the diagnostic value of PCT measured in umbilical cord blood before this physiological increase as an early and specific marker of neonatal bacterial sepsis. STUDY DESIGN PatientsWe conducted a prospective study from November 2003 to April 2004 in all children born with a suspected maternofetal infection. Three groups were defined according to clinical, biological, and bacterial criteria: infected, colonised, and noninfected non-colonised. Infected neonates had clinical and postnatal biological signs of sepsis, and a positive central (blood or cerebrospinal fluid) or peripheral bacteriological sample. Colonised neonates had a positive gastric sample, without any clinical or biological sign of sepsis. Non-infected non-colonised neonates had no sign of infection and a negative gastric sample. We also studied a group of newborns without any risk factors, which constituted a control group. MeasurementsWe measured PCT concentration in umbilical cord blood samples using an immuno-chromatographic semiquantitative test (PCT-Q; Brahms, Hennigsdorf, Germany) and C reactive protein (CRP) concentration using an immunoreactive quantitative method. We also measured PCT in maternal blood to evaluate its relevance in the diagnosis of chorioamnionitis. Judgment criteriaThe first judgment criterion was the sensitivity, specificity, and positive and negative predictive values, and positive and negative likelihood ratios of PCT, as assessed by a comparison of PCT concentrations in infected neonates with those in the groups of colonised and non-infected non-colonised neonates. The second criterion involved a comparison of PCT and CRP as predictive markers of neonatal infection. RESULTSA total of 197 newborn infants (167 with suspected maternofetal infection and 30 in the control group) were included in the study; 161 were full term and 36...
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