Closure of the ductus venosus in premature infants: findings on real-time gray-scale, color-flow Doppler, and duplex Doppler sonography

OBJECTIVE: Our objective was to use gray-scale, color-flow, and duplex Doppler sonography to study the anatomy, flow pattern, and time of closure of the ductus venosus in healthy premature infants. SUBJECTS AND METHODS: We prospectively examined the ductus venosus in 130 premature infants whom we divided into two groups: Group I comprised 27 neonates of gestational age 28-32 weeks, and group II comprised 103 neonates of gestational age 33-36 weeks. Neonates who had undergone umbilical vessel manipulation were excluded from the study. All examinations included gray-scale, color-flow, and duplex Doppler sonography. Patency, length, color flow, and Doppler characteristics of the ductus venosus were recorded. Neonates were examined 1-2 days after birth, 6-7 days after birth, and subsequently every 3-4 days until ductus closure was observed. The time of closure of the ductus for the two groups was compared using the chi-square test. RESULTS: The ductus venosus was patent during the initial examination in 128 of the 130 neonates. Doppler waveform was venous with little variation in velocity. Ductus length slightly exceeded 1 cm in both groups. We found a statistically significant difference in the percentage of infants having a patent ductus venosus after the initial examination: At 1 week after birth, ductus patency was shown in 85% of the infants in group I and in 56% of the infants in group II; at 2 weeks, the respective percentages were 42% and 14%; and at 3 weeks, 27% and 0%. CONCLUSION: The ductus venosus is patent 1-2 days after birth in virtually all premature infants. From 6 days after birth and onward, a significantly greater percentage of smaller premature infants (i.e., 28-32 weeks' gestational age) have a patent ductus venosus than do larger premature infants (i.e., 33-36 weeks' gestational age).     

Surgical ligation of patent ductus arteriosus in very low birth weight infants: is it safe?

We evaluated the outcome of a combined medical and surgical treatment of patent ductus arteriosus (PDA) in newborns weighing less than 1500 g. Charts were retrospectively reviewed for 76 newborns with a PDA between 1993 and 1997. Thirteen infants had pre-existing conditions prohibiting the use of indomethacin; eight were managed surgically, five medically. The remaining 63 infants received indomethacin therapy. Thirty-two medical failures occurred, requiring surgical ligation of the PDA. Those requiring surgery had a lower average birth weight (847 versus 997 g) and gestational age (26 versus 28 weeks; P < 0.05). Indomethacin treatment was successful in 27 infants. There were only three operative complications: a small pneumothorax, wound bleeding, and a small aortic tear. All recovered uneventfully and no deaths were attributable to the surgical procedure itself. There was no difference in the incidence of respiratory distress syndrome, duration of intubation, sepsis, neonatal enterocolitis, renal dysfunction, bleeding disorders, or intraventricular hemorrhage among both groups. Surgical ligation of a PDA is associated with a high success rate, a low incidence of complications, and no additional morbidity than indomethacin alone. We propose that surgical ligation should be regarded as a first line therapy for very small premature infants who are at higher risk of medical failure.     

Citalopram in the treatment of obsessive-compulsive disorder: an open pilot study

PURPOSE: To evaluate QT dispersion in hypertensive patients, with and without left ventricular hypertrophy, and compare with normal persons. METHODS: Thirty eight patients (21 male and 17 female, age 55 +/- 15 years) underwent echocardiography and simultaneous 12 lead, vertically aligned, electrocardiogram at 50 mm/s speed. No patient was on antiarrhythmic therapy. There were 19 non-hypertensive patients that constituted the control group (G-I). Group II was constituted by the other 19 patients, who were hypertensives. This group was further divided in group II-A (9 patients without left ventricular hypertrophy) and group II-B (10 patients with left ventricular hypertrophy). QT dispersion was obtained by the difference between the longest and the shortest QT registered. RESULTS: QT dispersion was significantly increased on hypertensive patients, both with and without left ventricular hypertrophy, when compared to controls (G-I 31 +/- 9 ms, G-II 52 +/- 15 ms. P < 0.0001; G-IIa 46 +/- 10 ms and G-IIb 56 +/- 18 ms X G-I, p < 0.0005). In hypertensive patients, there was no statistically significant difference between group II-A and group II-B. CONCLUSION: We conclude that QT dispersion is significantly increased on hypertensive patients when compared to non-hypertensive individuals and that such increase, occurs before left ventricular hypertrophy develops. These findings suggest that, in hypertensive patients, electrical changes in left ventricular myocardium can precede structural and morphological abnormalities. Such findings offer new insights into the mechanisms related to enhanced mortality among hypertensive patients.     

Optimal timing of retina examinations for premature infants

Developments in modern neonatal intensive care have resulted in increased survival of very premature infants. Along with this increase in survival, there has been a concomitant increase in the frequency of retinopathy of prematurity (ROP). We investigated the relationship between the severity and the time course of ROP as well as the optimal time for retinal examinations of premature infants of various birth weights and gestational ages. A total of 80 premature infants were enrolled for analysis. The mean postnatal age of infants at the time of diagnosis was 7.3 +/- 3.4 weeks for stage 1 retinopathy, 9.2 +/- 5.8 for stage 2 retinopathy, 9.5 +/- 3.8 for stage 3 retinopathy, 10.7 +/- 3.7 for threshold disease, and 11.7 +/- 3.2 for stage 4 retinopathy. The mean postconceptional age of infants at the time of diagnosis was 35 +/- 3 for stage 1 retinopathy, 36.4 +/- 3 for stage 2 retinopathy, 37.6 +/- 3.5 for stage 3 retinopathy, 38.4 +/- 3.5 for threshold disease, and 40 +/- 3.7 for stage 4 retinopathy. The age at the time of the initial detection of ROP was from the ninth to 10th week among infants weighing less than 1,000 g at birth and from the fifth to seventh week among those weighing 1,000 g or more at birth. However, the postconceptional age at the time of initial detection of ROP for the whole group was 36 weeks and was not influenced by birth weight or gestational age. Therefore, we suggest that postconceptional age, rather than postnatal age, should be used to decide the timing of retinal examinations for premature infants.     

The premature infant below 1000 g

74 premature infants with a birth weight of 1000 g or less were hospitalized in the period 1963-1975. 20 babies survived the first 4 weeks of life and 2 died during the second month of life from progressive lung disease. 77% of all patients were mechanically ventilated and 9 ventilated patients survived. The main causes of death were cerebral hemorrhage, severe asphyxia and septicemia. Prognosis was impaired by hypothermia, IRDS, gestational age below 27 weeks and premature rupture of membranes with bacterial infection. At the age of 1 year 8 out of 12 survivors followed up showed normal mental and motoric development. 3 children had minor or obvious signs of cerebral paresis and one further child has partial retrolental fibroplasia. Due to modern intensive care the survival rate of these very small premature babies has now reached 40%. The prognosis is favourably influenced by optimal obstetric and neonatal care, while special precautions should be undertaken to avoid hypothermia. Our results with mechanical ventilation justify the administration of full intensive care to these very small premature babies.     

Prevention of neonatal respiratory distress syndrome through the administration of prednisolone in the fetal period

The clinical effectiveness of antenatal prednisolone medication (prednisolone hemisuccinate) for the prophylaxis of idiopathic respiratory distress syndrome (IRDS) was studied in 114 premature infants with a gestational age between 28 and 36 weeks. There was a statistically significant difference (chi2 - test, p less than 0,01) between the frequency of IRDS in this group and in another one consisting of 137 premature babies with a nearly identical distribution of gestational age, whose mothers did not get prednisolone before delivery. It could be shown that the time interval between medical induction and delivery should not exceed 2 weeks, since the effect decreases with time. At present prednisolone medication during the fetal period may serve as useful prophylactic measure for IRDS in cases of premature birth. As there are a lot of contraindication against prednisolone and as we do know very much about side effects, it seems necessary to seek for other, less dangerous inductors.     

Survival after necrotizing enterocolitis in infants weighing less than 1,000 g: 25 years' experience at a single institution

Necrotizing enterocolitis (NEC) primarily affects premature newborns. Regional and national decreases in the mean birthweight and gestational age of neonatal intensive care unit (NICU) admissions prompted a review of NEC in VLBW (very low birth weight, defined as < 1,000 g) infants in our institution over a 25-year period. There were 266 patients treated for NEC during the study interval. We compared 71 VLBW with 195 non-VLBW infants and found that VLBW infants were: fed later (6.4 days v 4.1 days, P = .009), developed NEC later (20.8 days v 13.1 days, P = .002), had significantly lower 1- and 5-minute Apgar scores, were more likely to require surgery (51% v 34%, P = .016), more often had panintestinal (defined as > 75% of intestinal length) involvement (10% v 4%, P = .043), and had poorer survival (56% v 72%, P = .013). Overall survival after NEC has improved over the study interval, both in our series and in other reports. However, the increasing number of VLBW infants who have NEC represent a subgroup who appear to be generally more ill, develop NEC later, require surgery with greater frequency than their non-VLBW counterparts, and are less likely to survive.     

Randomized multicenter trial comparing synchronized and conventional intermittent mandatory ventilation in neonates

OBJECTIVE: To compare synchronized intermittent mandatory ventilation (SIMV) and conventional intermittent mandatory ventilation (IMV) in neonates. STUDY DESIGN: Prospective, multicenter, randomized clinical trial. SETTING: Level III neonatal intensive care units at six university or children's hospitals. PATIENTS: Three hundred twenty-seven infants receiving conventional IMV for respiratory distress syndrome, pneumonia, or meconium aspiration pneumonitis were randomly assigned a 7.5 +/- 6 hours of age to either continue with IMV or change to SIMV. Infants assigned to each mode of ventilation had similar birth weight (BW), gestational age, and Apgar scores at birth, and similar oxygenation indexes at randomization. They received similar surfactant therapy and had similar incidence of sepsis, seizures, secondary pneumonia, and necrotizing enterocolitis. In the infants with BW less than 1000 gm, more infants receiving IMV had surgical ligation of their patent ductus arteriosus than did those receiving SIMV (27 vs. 7 %; p = 0.02). ANALYSIS: Data was analyzed overall for all infants and also separately within three BW groups: less than 1000 gm, 1000 to 2000 gm, and more than 2000 gm. The 1000 to 2000 gm BW group was further analyzed in subgroups weighing 1000 to 1499 gm and 1500 to 2000 gm. RESULTS: In all infants, at 1 hour after randomization, the infants receiving SIMV had a lower mean airway pressure than those receiving IMV (8.08 +/- 2.15 vs. 8.63 +/- 2.59; p<0.05), with similar fractions of inspired oxygen and oxygenation indexes. Infants whose BW was 1000 to 2000 gm at 0.5 hour required a lower fraction of inspired oxygen with SIMV than with IMV (0.52 +/- 0.20 vs. 0.62 +/- 0.27; p<0.05) and had better oxygenation at 1 hour, as shown by lower oxygenation indexes with SIMV than with IMV (6.14 +/- 4.17 vs. 9.42 +/- 8.41; p = 0.01). Infants whose BW was 1000 to 2000 gm received a lower number of unit doses of sedative/analgesic drugs per infant during the first 4 days of SIMV than did infants receiving IMV (3.8 +/- 3.4 vs 6.3 +/- 5.5 unit doses; p = 0.02). Infants whose BW was more than 2000 gm had a shorter duration of mechanical ventilation with SIMV than with IMV (median, 72 vs 93 hours; p = 0.02). Three of the forty-six infants receiving IMV but none of the 47 infants receiving SIMV required extracorporeal membrane oxygenation. In the infants with BW less than 1000 gm, fewer infants treated with SIMV required supplemental oxygen at 36 weeks of postconceptional age than did those treated with IMV (47 vs 72%; p<0.05). In 83 infants whose lungs were mechanically ventilated for 14 days or longer, all with BW less than 2000 gm, those treated with SIMV regained their BW earlier than those treated with IMV (median, 21.5 vs 29 days; p<0.01). There were no differences in the rates of death, intraventricular hemorrhage (grades III and IV), air leak, need for pharmacologic paralysis, or need for supplemental oxygen at 28 days. CONCLUSIONS: We found that SIMV was at least as efficacious as conventional IMV, and may have improved certain outcomes in BW-specific groups.     

Population pharmacokinetic modeling in very premature infants receiving midazolam during mechanical ventilation: midazolam neonatal pharmacokinetics

BACKGROUND: Midazolam is used widely as a sedative to facilitate mechanical ventilation. This prospective study investigated the population pharmacokinetics of midazolam in very premature infants. METHODS: Midazolam (100 microg/kg) was administered as a rapid intravenous bolus dose every 4-6 h to 60 very premature neonates with a mean (range) gestational age of 27 weeks (24-31 weeks), a birth weight of 965 g (523-1,470 g), and an age of 4.5 days (2-15 days). A median (range) of four (one to four) blood samples, 0.2 ml each, were drawn at random times after the first dose or during continuous treatment, and concentrations of midazolam in serum were assayed by high-performance liquid chromatography. A population analysis was conducted using a two-compartment pharmacokinetic model using the NONMEM program. RESULTS: Average parameter values (interpatient percent coefficient of variation) for infants with birth weights 1,000 g or less were total systemic clearance (Cl(T)) = 0.783 ml/min (83%), intercompartmental clearance (Cl(Q)) = 6.53 ml/min (116%), volume of distribution of the central compartment (V1) = 473 ml (70%), and volume of distribution of the peripheral compartment (V2) = 513 ml (146%). For infants with birth weights more than 1,000 g they were as follows: Cl(T) = 1.24 ml/min (78%), Cl(Q) = 9.82 ml/min (98%), V1 = 823 ml (43%), and V2 = 1,040 ml (193%). The intrapatient variability (percent coefficient of variation) in the data was 4.5% at the mean concentration midazolam in serum of 121 ng/mL CONCLUSIONS: Serum concentration-time data were used in modeling the population pharmacokinetics of midazolam in very premature, ventilated neonates. Clearance of midazolam was markedly decreased compared with previous data from term infants and older patients. Infants weighing less than 1,000 g at birth had significantly lower clearance than those weighing more than 1,000 g.     

Influence of infection on patent ductus arteriosus and chronic lung disease in premature infants weighing 1000 grams or less

OBJECTIVES: To test the hypotheses that (1) infection increases ductal dilatory prostaglandins and inflammatory mediators that may influence the closure of a patent ductus arteriosus (PDA), increasing the incidence of late episodes of PDA (after 7 days) and the rate of closure failures, and (2) the concurrence of PDA and infection increases the risk of chronic lung disease (CLD). METHODS: One hundred fourteen premature infants (birth weight, 500 to 1000 gm) were prospectively assessed for PDA and infection. Serum levels of 6-ketoprostaglandin F1 alpha and tumor necrosis factor alpha were measured routinely in all infants and when PDA or infection was present. Multivariate assessment of risk factors for PDA closure failure and for CLD was done by logistic regression, and expressed as an odds ratio and as 95% confidence intervals. RESULTS: Late PDA episodes were more frequent in infants with infection than in those without infection. A temporally related infection (<5 days between both diagnoses) was associated with an increased risk of PDA closure failure (odds ratio, 19.1 (confidence interval, 4 to 90)). In addition to birth weight and the severity of initial respiratory failure, PDA and infection increased the risk of CLD (odds ratio, 11.7 (confidence interval, 1.7 to 81) for PDA; odds ration, 3.1 (confidence interval, 1 to 11) for infection). Furthermore, when both factors were temporally related, they further increased the risk of CLD (odds ratio, 29.6 (confidence interval, 4.5 to >100)). Infants with infection and those with PDA had higher levels of 6-ketoprostaglandin F1 alpha than did control subjects. Levels of tumor necrosis factor alpha were also elevated in infants with infection and in those with late PDA. CONCLUSIONS: Infection adversely influences PDA outcome by increasing the risk of late ductal reopening and PDA closure failures. Increased levels of prostaglandins and tumor necrosis factor alpha in infants with infection may explain the poor PDA outcome. The concurrence of PDA and infection potentiates their negative effects on the risk of CLD.     

Diurnally changing effects of locomotor activity on body temperature in laboratory mice

BACKGROUND: It is uncertain whether proximal pulmonary artery (PA) obstruction exists soon after birth and whether its progress relates directly to postnatal ductal constriction in congenital heart disease and obstructed pulmonary flow. METHODS: Serial morphometric analyses of the PA branches by echocardiogram were performed in 28 patients (mean age at initial study 2.5 days) until severe constriction of the ductus occurred (mean age 47 days). These patients were divided into 2 groups by subsequent angiographic or postmortem confirmation; 10 with proximal PA obstruction (group 1) and 18 without obstruction (group 2). RESULTS: At the time of initial examination, the mean indexed diameter of the proximal PA on the side of the ductus arteriosus in group 1 was significantly smaller than that on the contralateral side (5.2+/-0.7 versus 9.0+/-0.7 mm/BSA0.5, P < .001) or that in group 2 (8.0+/-0.4 mm/BSA0.5, P < .001). In group 1, 8 patients had a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5, which was less than those of any group 2 patients. After severe constriction of the ductus, the proximal PA index on the ductal side further decreased only in group 1 (P < .01). CONCLUSIONS: These data indicate that unilateral obstructive lesion of branch PA is present shortly after birth and its progression relates directly to ductal constriction. Neonates with branch PA obstruction can be identified on their initial echocardiogram as having a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5.     

Melatonin in relation to the antioxidative defense and immune systems: possible implications for cell and organ transplantation

Inguinal hernia (IH) is relatively common in premature newborn infants, and the timing of surgical correction is controversial. We studied 40 premature infants who developed an IH and who were initially treated in a neonatal intensive care unit. Birth weight (BW) ranged from 492 to 2,401 g; 21 infants had a BW less than 1,000 g. The weight of the infants at operation ranged from 1,000 to 4,400 g. Twenty-one patients underwent herniotomy within 2 weeks after the diagnosis (short waiting group), in which 1 case of incarceration occurred; 19 waited longer than 2 weeks between diagnosis and surgery (long waiting group). Two cases of strangulation occurred in this latter group, and in 1 of those testicular necrosis occurred. Operation time was analysed in boys with bilateral herniotomy (n = 25): the short waiting group (n = 12) showed a significantly reduced operation time compared to the long waiting group (n = 13). Patients weighing less than 1,000 g at birth (n = 21) had a longer average waiting period for surgery. In the group of male patients with bilateral herniotomy, average operation time was longer in the group weighing less than 1,000 g at birth (n = 13) than in the group over 1,000 g (n = 12). Body weight at surgery did not affect operation time. It is concluded that early hernia repair should be considered in premature infants to avoid operative difficulties and gonadal ischaemia caused by incarceration.     

"Silent" patent ductus arteriosus and bronchopulmonary dysplasia in low birth weight infants

We conducted a clinical study on the antecedents of bronchopulmonary dysplasia (BPD) in 290 premature RDS infants with < or = 1.75 kg birth weight (BW). They were enrolled in a prospective trial of indomethacin treatment for "silent" patent ductus arteriosus (PDA), screened by 2-D echocardiographic and pulsed Doppler evaluation on the third day of life. The trial took place at the NICU of the Pediatric Department of Padua University between January 1987 and December 1991. Out of 290 infants screened, 96 had evidence of "silent" PDA (33%) and 77 responded to indomethacin treatment (80%). Comprehensively 79 (27%) developed BPD, and from these the incidence of BPD was statistically increased in infants with "silent" PDA, 47 out of 96 (49 +/- 9%), with respect to 32 out of 194 (16 +/- 3%) preterm infants without PDA. Statistical analysis showed that in preterm infants with "silent" PDA the development of BPD was correlated at 99% C.L. to their low BWs (mean BW = 1.13 kg): in fact the mean and the mode of BW distributions were statistically lower in the presence of BPD, 1.03 kg versus 1.24 kg, and 0.88 kg versus 1.65 kg respectively. Moreover, the preterm infants with "silent" PDA unresponsive to the first course of indomethacin and/or submitted later to surgical closure, presented a statistically lower BW with respect to the early responders, 1.06 kg versus 1.18 kg, and at the same time a statistically higher incidence of BPD (63 +/- 20% versus 43 +/- 9%). From these data we conclude that, although "silent", PDA increase per se the incidence of BPD, even if benefits from an early induced closure. Furthermore, a lower BW of infants affected by "silent" PDA represents a contributing factor to the development of BPD.     

Long-term follow-up after bowel resection for necrotizing enterocolitis: factors affecting outcome

BACKGROUND: Necrotizing enterocolitis (NEC) is the most common surgical emergency among newborns and is associated with a high morbidity and mortality. This study evaluates the long-term survival of infants requiring surgical intervention for NEC and factors affecting outcome. METHODS: A retrospective review of infants requiring surgery for complications of NEC at a tertiary care, pediatric hospital over a 16-year period was performed. Patients were evaluated for early and late morbidity and mortality, length of intestinal resection, presence of the ileocecal valve (ICV), days of parenteral nutrition (PN), and growth. RESULTS: Two hundred forty-nine patients were included, with an average gestational age of 30 +/- 5 (+/- SD) weeks and birth weight of 1.50 +/- 0.89 kg. The surgical mortality rate was 45%, with survivors (137) being larger (P < .001) and older (P < .001) at time of birth than nonsurvivors. Mortality rates varied inversely with gestational age and birth weight. Surgical survivors had an average of 21 +/- 26 cm of intestinal length resected. The ileocecal valve was preserved in 45% of infants. Growth was similar between infants with or without an ICV. Stratification of length of intestine resected showed that infants with larger resections had greater requirements for parenteral nutrition, but this had no influence on long-term growth at follow-up. CONCLUSIONS: Survivors of NEC are characterized by greater gestational age, greater birth weight, and older postgestational age at surgery. Infants who underwent greater intestinal resections required longer periods of PN. The length of intestine resected or presence of the ileocecal valve had no overall bearing on long-term outcome.     

Ligation of medically refracted patent ductus arteriosus (PDA) in an extremely low body weight premature infant

Medically refracted patent ductus arteriosus (PDA) in an extremely low birth weight (ELBW) preterm (gestation 24 weeks 2 days) infant was successfully ligated under general anesthesia in the neonatal intensive care unit (NICU). Pharmacological agents are more effective to close PDA in preterm infants than in full-term infants, although within 48 h three doses of indomethacin were not sufficient to close PDA in this case. At the age of 69 h the infant developed severe symptoms including bradycardia, systemic hypotension, pulmonary hypertension, diastolic steal (reverse distal aorta flow velocity), and anuria. A PDA ligation was thus performed surgically at 72 h of age. General anesthesia and surgical stress were tolerated by this 531 g infant. Postoperatively all symptoms improved dramatically and the general conditions were stable. On the 38th day the endotracheal tube was extubated and on the 50th day nasogastric milk feeding was started. The oxygen supply was weaned on the 78th day. Growth and development until 6 months were within the normal range of very low birth weight infants. A surgical ligation as early as possible in medically refracted PDA in an ELBW infant is thus considered to be a safe and effective treatment. It prevents the development of further complications of cardiopulmonary vascular problems. Color Doppler echocardiography can reliably measure the PDA size, flow velocity, and hemodynamic changes of persistent PDA, even in tiny infants.     

Temperature control in very low birthweight infants during first five days of life

AIM: To determine ranges for skin temperatures in infants weighing under 1000 g in the first five days of life. METHOD: Abdominal skin and foot temperatures were automatically collected each second, averaged over 1 minute and stored on computer. A computer program analysed the data in 83 babies weighing under 1000 g at birth over the first five days of life and expressed the temperatures as means and standard deviation. The temperature patterns seen in these babies were also visually analysed. The relation between an increasing abdominal skin-foot temperature difference and other signs of hypovolaemia was also studied. RESULTS: These babies all had similar temperature patterns. Just after birth there was little ability to vasoconstrict in the presence of cold stress and the babies behaved more like poikilothermic animals. Vasomotor tone developed in the first three days, resulting in a stabilisation of the abdominal skin temperature to a mean of 36.9 degrees C and a widening of the central-peripheral temperature difference (Td) to a mean of 1.0 degree C. A Td of > 2 degrees C was associated with other evidence of hypovolaemia for only 11% of the time. CONCLUSIONS: Infants weighing under 1000 g have poor vasomotor control at birth and are at increased risk from cold stress. After the first two to three days of life, monitoring the central-peripheral temperature difference gives an early indication of cold stress.     

Causes of perinatal mortality in twins

The author analyses perinatal mortality in 244 twin pregnancies. In 80% the twins' Apgare score at birth was 10 to 8 and neonatal mortality in this group 1.26%. The slightly asphyxial group (Apgar 7 to 4) comprised 62 (38.75%) twins and the neonatal mortality in this group was 14.51%. There were 20 (12.5%) severely asphyxial (Apgar 3 or less) twins, their neonatal mortality amounting to 80.0%. Out of 193 twins weighing at birth less than 2500 g, 45 (23.31%) died, while in the twins weighing more than 2500 g there was not a single death. The perinatal mortality of twins up to the 37th week of pregnancy amounted to 17.37% and from the 38th week of pregnancy to 1.22%. The mean duration of pregnancy in twins was 38.1 +/- 2 SD 6.3 weeks. The most frequent cause of death in twins has proved to be immaturity and asphyxia at birth, leading to the development of hyaline membranes (80.0%). Other causes were far less frequent. The author concludes that in the perinatal mortality of twins their vitality at birth (assessed by the Apgar score), birth weight, and the duration of pregnancy play an important role.     

Regional differences of cerebral blood flow in the preterm infant

The purpose of our study was to evaluate the regional distribution of the resting cerebral blood flow (CBF) pattern in preterm neonates. Sixty-eight preterm babies with a gestational age of less than 34 weeks and a birth weight of less than 1500 g were enrolled into the study. The CBF was measured by the noninvasive intravenous 133Xenon method at three different times. Depending on the age we classified our measurements into three groups. Group 1: measurement between 2-36 h (n = 46). Group 2: measurement between 36-108 h (n = 39). Group 3: measurement between 108-240 h (n = 41). In all three groups CBF was significantly lower in the occipital region than in the frontal and parietal regions (group 1: frontal region 12.8 +/- 3.5 ml/100 g/min, parietal region 12.8 +/- 3.9 ml/100 mg/min, and occipital region 11.6 +/- 3.18 ml/100 g/min; group 2: frontal region 15.4 +/- 4.2 ml/100 g/min, parietal region 15.3 +/- 4.1 ml/100 g/min, and occipital region 13.4 +/- 3.5 ml/100 g/min; group 3: frontal region 14.6 +/- 3.6 ml/100 g/min, parietal region 14.6 +/- 3.2 ml/100 g/min, and occipital region 12.8 +/- 2.7 ml/100 g/min.). CBF did not differ between the left and the right hemispheres in either of the three measured regions. No gradient was found in infants between 108 h and 240 h of age with periventricular leukomalacia and periventricular haemorrhage. CONCLUSION. In preterm neonates the antero-posterior gradient of CBF is already present. Periventricular leukomalacia as well as periventricular haemorrhage may affect the regional regulation of CBF.     

Effects of aerosolized surfactant in patients with stable chronic bronchitis: a prospective randomized controlled trial

BACKGROUND/AIMS: Fulminant hepatic failure (FHF) is usually fatal without liver transplantation. Auxiliary heterotopic partial liver transplantation (AHPLT) may offer advantages over orthotopic liver transplantation (OLT) or any other heterotopic procedure for the treatment of patients with fulminant liver failure. We studied AHPLT in a severe acute hepatic failure model in pigs. METHODOLOGY: Group A (control: n = 5) underwent portal vein and hepatic artery ligation and side-to-side portocaval shunting. Group B (AHPLT: n = 15) underwent host portal vein and hepatic artery ligation and AHPLT. RESULTS: All of the pigs in group A died within 48 hours from massive liver necrosis. Ten of the 15 pigs (67%) in group B had well-functioning grafts. Five of these ten died between 8 and 17 days postoperatively due to various complications. The remaining five survived for sixty days postoperatively in healthy condition. At the time of sacrifice, four of these five had well-functioning grafts weighing 739 +/- 52 g (mean +/- SEM) and regenerated, but still atrophied, host livers weighing 262 +/- 23 g (p < 0.0002). On the other hand, the one remaining pig had an atrophied graft weighing 310 g and a well-regenerated host liver weighing 470 g, probably due to a late, poorly functioning graft associated with severe rejection. CONCLUSION: AHPLT may result in survival despite host hepatic failure, and the host liver may recover within two months, despite total interruption of blood inflow.     

Arterial oxygen saturation in Tibetan and Han infants born in Lhasa, Tibet

BACKGROUND: Reduced oxygen availability at high altitude is associated with increased neonatal and infant mortality. We hypothesized that native Tibetan infants, whose ancestors have inhabited the Himalayan Plateau for approximately 25,000 years, are better able to maintain adequate oxygenation at high altitude than Han infants, whose ancestors moved to Tibet from lowland areas of China after the Chinese military entered Tibet in 1951. METHODS: We compared arterial oxygen saturation, signs of hypoxemia, and other indexes of neonatal wellbeing at birth and during the first four months of life in 15 Tibetan infants and 15 Han infants at 3658 m above sea level in Lhasa, Tibet. The Han mothers had migrated from lowland China about two years previously. A pulse oximeter was placed on each infant's foot to provide measurements of arterial oxygen saturation distal to the ductus arteriosus. RESULTS: The two groups had similar gestational ages (about 38.9 weeks) and Apgar scores. The Han infants had lower birth weights (2773 +/- 92 g) than the Tibetan infants (3067 +/- 107 g), higher concentrations of cord-blood hemoglobin (18.6 +/- 0.8 g per deciliter, vs. 16.7 +/- 0.4 in the Tibetans), and higher hematocrit values (58.5 +/- 2.4 percent, vs. 51.4 +/- 1.2 percent in the Tibetans). In both groups, arterial oxygen saturation was highest in the first two days after birth and was lower when the infants were asleep than when they were awake. Oxygen saturation values were lower in the Han than in the Tibetan infants at all times and under all conditions during all activities. The values declined in the Han infants from 92 +/- 3 percent while they were awake and 90 +/- 5 percent during quiet sleep at birth to 85 +/- 4 percent while awake and 76 +/- 5 percent during quiet sleep at four months of age. In the Tibetan infants, oxygen saturation values averaged 94 +/- 2 percent while they were awake and 94 +/- 3 percent during quiet sleep at birth and 88 +/- 2 percent while awake and 86 +/- 5 percent during quiet sleep at four months. Han infants had clinical signs of hypoxemia--such as cyanosis during sleep and while feeding--more frequently than Tibetans. CONCLUSIONS: In Lhasa, Tibet, we found that Tibetan newborns had higher arterial oxygen saturation at birth and during the first four months of life than Han newborns. Genetic adaptations may permit adequate oxygenation and confer resistance to the syndrome of pulmonary hypertension and right-heart failure (subacute infantile mountain sickness).