Posttransfusion hemoglobinuria and myoglobinuria in neonates

Posttransfusion positive dipsticks for occult blood do not differentiate hemoglobinuria from myoglobinuria, relatively common events in infants admitted to the neonatal intensive care unit. We studied posttransfusion plasma and urine hemoglobin and myoglobin in relation to occult blood positivity in the urine dipsticks, in 48 consecutive transfusions with packed RBC (28 neonates, birth weight 850-3,700 g, postnatal age 3-167 days). Urine dipsticks show a low sensitivity for detecting hemoglobin and also undervalue myoglobin, both possible in different amounts in the plasma and urine of ill neonates. However, posttransfusion occult blood positive urine dipsticks due to myoglobinuria are present in 10% of transfused neonates.     

Reference values of perfusion indices in hemodynamically stable newborns during the early neonatal period

We aimed to determine reference values of perfusion index (PI) in healthy newborns during the early neonatal period. Preductal (right hand) and postductal (foot) PI values were assessed during the first 5 days of life by using a new generation pulse oximetry. A total of 241 newborn infants (196 [81.3 %] term and 45 [18.7 %] preterm) were enrolled to the study. On the first day, in term infants, the median (interquartile range [IQR]) preductal and postductal PI were 1.35 (1.02–1.91) and 0.88 (0.62–1.22), respectively (p?=?0.001). These values were 0.88 (0.60–1.26) and 0.61 (0.35–0.92) in preterm infants, with the same respect (p?=?0.001). From the first to third days, preductal PI remained significantly higher than the postductal PI (p?<?0.001, for all comparisons). Both preductal and postductal PI of term newborns were significantly higher than those of preterm infants (p?<?0.001, for both comparisons). These differences in PI disappeared on the fifth day of life. Conclusion PI values which reflect peripheral perfusion seem to reach to a steady state on the fifth day of life following physiological maturation.     

Blood viscosity and optimal hematocrit in preterm and full-term neonates in 50- to 500-micrometer tubes.

Blood viscosity is an important determinant of blood flow resistance. Because a substantial part of flow resistance arises in small arteries and arterioles with diameters of 100 microns and less, rheologic properties of blood from preterm infants (24 to 36 wk of gestation), full-term neonates, and adults were measured in glass tubes with diameters of 50, 100, and 500 microns for a wide range of adjusted feed hematocrits (0.15-0.70). At each of the feed hematocrits, blood viscosity decreased when going from a 500-microns tube to a 50-microns tube. The viscosity reduction increased with increasing hematocrit. Moreover, the viscosity reduction was more pronounced in the neonates than in the adults. At a hematocrit of 0.70, the viscosity reduction averaged 56% in preterm infants, 50% in full-term neonates, and 39% in adults (p less than 0.005). However, the viscosity reductions at a hematocrit of 0.30 were only 35, 29, and 19%, respectively (p less than 0.05). In all four groups, blood viscosity increased exponentially with increasing hematocrit. The steepness of the hematocrit-viscosity curves decreased with decreasing tube diameter and with decreasing maturity of the infants. Erythrocyte transport efficiency (hematocrit/blood viscosity) was calculated to estimate the optimal hematocrit (i.e. hematocrit with maximum erythrocyte transport). In 500-microns tubes, the optimal hematocrit was about 0.40 in all of the groups. In 100-microns tubes, the optimal hematocrit was 0.44 +/- 0.05 in the adults and 0.52 +/- 0.04 in the neonates (p less than 0.05). In 50-microns tubes, the optimal hematocrit was 0.51 +/- 0.04 in adults and 0.60 +/- 0.05 in the neonates.(ABSTRACT TRUNCATED AT 250 WORDS)     

临床和血流动力学稳定的早产儿生后第1周灌注指数变化

重症监护病房的新生儿,尤其是早产儿,生后第1周患病和死亡率较高,因而早期诊断新生儿各种并发症是新生儿医务工作者面临的巨大挑战。近年来,脉搏血氧仪(简称脉氧仪)已成为新生儿重症监护病房(NICU)的重要监测仪器之一。据报道,通过脉氧仪信号得出的灌注指数(perfusion index,PI)能反映外周血流的实时变化,并识别外周循环灌注不足的重症新生儿。近期已有报道新生儿PI值的相关文献,但关于早产儿的还较少。本研究旨在监测临床和血流动力学稳定早产儿生后第1周的PI值,从而为临床上推广应用提供依据。研究方法一、研究对象2007年11月至2008年4月入住意大利某儿童医院NICU的30例早产儿。入选     

临床和血流动力学稳定的早产儿生后第1周灌注指数变化

重症监护病房的新生儿,尤其是早产儿,生后第1周患病和死亡率较高,因而早期诊断新生儿各种并发症是新生儿医务工作者面临的巨大挑战。近年来,脉搏血氧仪（简称脉氧仪）已成为新生儿重症监护病房（NICU）的重要监测仪器之一。     

Management of pneumothorax in hemodynamically stable preterm infants using high frequency oscillatory ventilation: report of five cases

Background

Despite an increased use of non-invasive ventilatory strategies and gentle ventilation, pneumothorax remains a common complication in preterm infants. The ventilator management of infants with air leaks remains challenging in terms of both prevention and treatment. Recently the safety and efficacy of expectant management avoiding chest tube drainage to treat large air leak in preterm infants hemodynamically stable has been reported.

Case presentation

In the present study, we report five cases of preterm infants with birth weight?≤?1250 g affected by respiratory distress syndrome and treated with nasal continuous positive airway pressure as first intention. They were intubated for worsening of respiratory distress with increasing oxygen requirement and concomitant increase of respiratory rate and P_CO2 values due to occurrence of pneumothorax, and they were successfully treated using high-frequency oscillatory ventilation without chest tube insertion.

Conclusion

In our experience high-frequency oscillatory ventilation provided a conservative management of a significant pneumothorax in preterm newborns hemodynamically stable and requiring mechanical ventilation. This approach allowed us to avoid the increasing of air leak and the insertion of chest tube drainage and all the subsequent associated risks.

     

Infective endocarditis in neonates.

Five patients with neonatal infective endocarditis were reviewed, two of whom survived. Infection was caused by Staphylococcus aureus in four and by Candida albicans in one. All cases of bacterial endocarditis had clinical signs of septicaemia, positive blood cultures, thrombocytopenia, microscopic haematuria, and heart murmurs. Three developed skin abscesses early in their illnesses. Three patients had two dimensional echocardiographic studies that showed bacterial vegetations. One of these studies was done before the heart murmur could be heard. We suggest that echocardiography in conjunction with the clinical picture described may help in making an early diagnosis of endocarditis in neonates.     

Transfusion therapy in neonates.

Infants, particularly those who were very small premature neonates, are among the most common of all patient groups to undergo extensive transfusion. It is estimated that approximately 300,000 neonates undergo transfusions annually. Most infants who undergo transfusion are exposed to multiple blood donors, and although each exposure poses only a small risk, the potential for adverse effects of multiple transfusions is not variable, and based on scanty scientific information. For the most part, controlled scientific studies have not been performed to clearly establish the indications for the transfusion of blood components to neonates. Considering these limitations, guidelines are offered for the transfusion of red blood cells, platelets, and neutrophils into neonates.     

Bladder emptying in neonates.

Ultrasound scanning was used to determine whether bladder emptying is complete when a newborn baby micturates. Residual urine was detected in 6 females and 9 males while one female emptied her bladder completely. The residual volume was estimated in 11 subjects and ranged from 3.9 to 13.9 ml. Incomplete bladder emptying cannot be the main factor in explaining the sex incidence of urinary tract infection in neonates.     

Type V hyperlipoproteinaemia in neonates.

A boy investigated for neonatal jaundice was noted to have lipaemic serum and was subsequently shown to have type V hyperlipoproteinaemia. Dietary treatment was maintained for five years and he followed a typical clinical course. Circumstantial evidence suggested an autosomal recessive inheritance pattern.     

Bronchial hypersecretion in preterm neonates.

During an 18-month period, 11 preterm infants with birthweights between 700 and 1560 g (mean 1.2 kg) developed excessive tracheobronchial secretions during intensive care. No single obstetric factor was incriminated. Copious, viscous, tracheobronchial secretions were noted at about 5 days during mechanical ventilation via endotracheal tube causing recurrent segmental collapse, hypoxia, and hypercapnia (median peak PCO2 13.5 kPa). All infants were treated with frequent bronchial lavages and continued intermittent positive pressure ventilation, together with high concentrations of oxygen. No infant died, but morbidity was high. Tracheostomy was performed on 2 infants (one at age 3 months, because of severe croup) and 2 others had clinical or physiological evidence of upper airways narrowing. Follow-up studies showed that this group had more problems of airways obstruction throughout the first year of life as well as increased lung stiffness. The hypersecretion group showed a higher incidence of chronic lung disease. Likely aetiological factors were sought. Contamination of the mechanical ventilation equipment by detergent and activated glutaraldehyde was found; this could have been a contributory factor.