The role of the duodenal microflora as a determinant of persistent diarrhoea

It has been suggested that proliferation of enterobacteriaceae and/or anaerobes in the duodenum of some children with acute diarrhoea determines whether the episode becomes persistent. A review of published studies and the comparison of cultures of duodenal aspirates from Peruvian children with acute and persistent diarrhoea and diarrhoea-free children did not support this hypothesis. Although many children had enterobacteriaceae and/or anaerobes cultured there was no correlation with clinical and nutritional outcome. Age, nutritional status, the environment and the aetiology of the episode were determinants of the duodenal microflora independent of diarrhoea. Culture of the duodenal aspirates did not increase the yield of enteropathogens which were isolated more frequently from stools than from the duodenum. Despite the presence of a single strain or serotype of enterobacteriaceae suggesting that these bacteria were colonizing the duodenum, we were unable to demonstrate any adherence mechanisms in the majority of them. Two often bacteria with no other evidence of virulence caused diarrhoea in the RITARD rabbit model.     

Hemodynamically significant PDA: An echocardiographic and clinical assessment of incidence,natural history,and outcome in very low birth weight infants maintained in negative fluid balance

Summary Fifty very low birth weight (VLBW) infants (750–1500 g, 27–33 weeks gestational age) were assigned at random to one of two groups of negative fluid balance and underwent prospective clinical and echocardiographic examinations during the first month of life. The purpose was to determine: (a) the effect of fluid restriction on the incidence of ductal shunting, (b) the reliability of the physical examination in diagnosing significant ductal shunting, and (c) the relationship between significant ductal shunting and outcome in such infants. None of the infants had manipulations to close the ductus during the first week of life. Using routine structural and functional echocardiographic indices as criteria for the diagnosis of hemodynamically significant ductal shunting (hsPDA), we found that the two fluid-balance groups (8%–10% weight loss vs 13%–15% weight loss) did not significantly differ in incidence of hsPDA, duration of ventilation, or development of BPD. These two groups were then combined for further analysis: 32 (64%) of 50 VLBW infants had hsPDA during the first week of life. The group of infants with hsPDA did not differ significantly from that without hsPDA in birth weight or gestational age, but had a significantly lower Apgar score (P<0.04) and was significantly more likely to require ventilator support for RDS (P<0.01). Although when present a typical ductal murmur was specific for the development of significant ductal shunting, no murmur was heard in 21 (66%) of 32 infants with early hsPDA. Of the infants requiring ventilator support for RDS, the group with early hsPDA needed ventilation for 13.8±9.4 days, significantly longer than the group without early hsPDA (3.2±2.6 days,P<0.001), and had a higher incidence of BPD and death than the group without early hsPDA (P<0.04). In our study of a large group of prospectively identified VLBW infants, we did not find that significant ductal shunting was altered by more stringent fluid restriction, but we did find that such shunting was frequently inapparent clinically, and was associated with significantly increased morbidity and mortality.This research was supported in part by Children's Hospital Research Foundation; DHHS-USPHS, MCH grant 000174; American Heart Association, SWOC; and by DRR CLINFO grant RR00068-18-52, General Clinical Research Center.     

Duration of ventricular ejection during spontaneous breathing and positive pressure ventilation in newborn infants

Experimental manipulations of intrathoracic pressure at the investigational level have been shown to result in demonstrable changes in ventricular outputs. To assess whether these changes are detectable in the clinical setting of newborn infants, we evaluated changes in the duration of left and right ventricular ejection during spontaneous breathing and during positive pressure ventilation. This was accomplished by measuring left and right ventricular ejection times (VETs) using echocardiography. Values from cardiac cycles during peak inspiration were compared to cycles that occurred during expiration. In 6 infants breathing spontaneously, the mean duration of right VET increased by 4.0% at peak inspiration, while the concomitant mean left VET decreased by 3.3%. In 14 infants requiring positive pressure ventilation, the mean duration of right VET decreased by 7.2% at peak inspiration, while the left VET increased by 2.5%. We conclude that changes in intrathoracic pressure associated with spontaneous breathing and with positive pressure ventilation result in detectable changes in ventricular ejection in the newborn infant.     

Hypertrophic cardiomyopathy in infants of diabetic mothers: an update

Infants of diabetic mothers (IDMs) are at known risk for developing a hypertrophic type of cardiomyopathy. The severity of IDM cardiomyopathy can vary from an incidental finding on echocardiography to an infant with severe symptoms of congestive heart failure. The purpose of this article is to review the pathophysiologic mechanisms involved in the development of cardiomyopathy in IDMs and to discuss the diagnostic tests utilized in making the diagnosis (especially echocardiography) and the potential mechanisms that may result in congestive heart failure. This report will conclude with a review of a 2 1/2 year prospective study of diabetic women who had carefully maintained diabetic control during pregnancy. Although the IDMs in this study continued to have mild evidence of generalized hypertrophy when compared with control newborn infants, none developed symptoms of congestive heart failure. These data support the contention that careful diabetic management in pregnancy reduces the severity of hypertrophic cardiomyopathy in IDMs.     

Fetal lamb ventricles respond differently to filling and arterial pressures and to in utero ventilation

Right and left ventricular function were investigated in 12 fetal lambs (127-140 days gestation) instrumented with electromagnetic flow sensors on the ascending aorta and the main pulmonary artery, and with vascular catheters. Nine fetuses were equipped with a postductal aortic occluder and the trachea was cannulated in eight. Control arterial blood values were pH 7.36 +/- 0.02 (SD), PCO2 49.3 +/- 2.3 torr, PO2 18.4 +/- 1.7 torr, and hematocrit 37.3 +/- 4.4%. Biventricular function curves relating stroke volume to mean right and left atrial pressure were generated by rapid withdrawal and reinfusion of fetal blood. Both function curves were composed of steep ascending and plateau limbs that intersected at a breakpoint. Stroke volumes at the breakpoints were 0.94 +/- 0.19 ml.kg-1 and 0.63 +/- 0.15 ml.kg-1 for right and left ventricle, respectively (p less than 0.001). During postductal aortic occlusion, arterial pressure increased by 19.3 +/- 7.9 torr while right ventricular stroke volume decreased by approximately 48% and left ventricular stroke volume decreased by approximately 9%. In utero ventilation increased arterial pressure, heart rate, PO2, and oxygen content. Right atrial pressure increased from 3.9 +/- 1.3 to 5.8 +/- 2.9 torr (p less than 0.05); left atrial pressure from 3.5 +/- 1.5 to 10.0 +/- 4.4 torr (p less than 0.05). Aortic flow nearly doubled (112 +/- 29 to 211 +/- 35 ml.min-1.kg-1) (p less than 0.05), and the left ventricular function curve shifted upward. The right ventricular function curve was shifted downward during ventilation. We conclude that the fetal ventricles differ significantly in their outputs, response to changes in arterial pressure, and to the onset of in utero ventilation.     

Surgical strategies in very-low-birthweight neonates with necrotizing enterocolitis

Very-low-birthweight (VLBW) neonates are more prone to complications and death than term infants are. In a 15-year period, 19 neonates with VLBW were operated on for necrotizing enterocolitis (NEC). Indications for operation were pneumoperitoneum in 12 and deterioration of general condition in 7. Bowel resection and intestinal diversion was performed in 12, a lateral enterostomy at the site of perforation was created in 5, and 2 neonates with necrosis of the whole bowel underwent an exploratory laparotomy without any further surgical treatment. Surgical complications were found in one-third of the patients. The mortality rate was significantly higher when the ileum was affected. The survival rate was 68%. Prior to 1984 the survival rate was 37% (3/8); subsequently, it has improved to 91% (10/11) as a result of improved intensive therapy.