Minimising neonatal brain injury: how research in the past five years has changed my clinical practice.

With improving neonatal survival for extremely premature babies, the challenge for neonatology is to improve outcome of surviving babies. This review concentrates on best evidence emerging in recent years on prevention of brain damage by early administration of drugs as well as avoidance of induced brain damage by hyperventilation and dexamethasone therapy given postnatally for chronic lung disease.     

Characterization of urgent versus nonurgent early readmissions (<30 days) following primary bariatric surgery: a single-institution experience

BackgroundStudies on early postoperative readmissions after bariatric surgery (BS) have examined readmissions as a single entity, regardless of urgency. Strategies to lower nonurgent readmissions would reduce unnecessary hospital utilization.ObjectivesTo identify predictors of urgent readmissions (UR) versus nonurgent readmissions (NUR) at 30 days post-BS.SettingSingle academic institution.MethodsPatients undergoing primary BS over 2 years (n = 589) were retrospectively reviewed. Baseline demographic, medical, and hospitalization data were compared between readmitted patients, stratified by urgency, and nonreadmitted patients. Multivariate regression models of UR and NUR were created using variables with a P value ≤ .2 on univariate analyses. A P value ≤ .05 was considered statistically significant.ResultsThere were 39 documented instances of 30-day readmissions, of which 44% (n = 17) were NUR; NUR patients were more likely to be female (100% versus 78.2% male; P = .03) and trended toward being younger, experiencing ≥2 perioperative complications, and having a longer index hospital length of stay (LOS). Patients with URs had a higher baseline BMI (52.5 ± 11.4 kg/m² versus 48.7 ± 8.3 kg/m², respectively; P = .04), were more likely to have sleep apnea (77.3% versus 56.1%, respectively; P = .05), had a longer LOS (3 versus 2 d, respectively; P = .007), and were more likely to have ≥2 postoperative complications (46% versus 17.0%, respectively; P = .003) compared with those with an NUR. Independent predictors of NUR included public insurance (odds ratio [OR] = 3.7; 95% confidence interval [CI], 1.17–11.67; P = .03), younger age (OR = 1.05; 95% CI, 1–1.01; P = .04), and female sex, while URs were independently predicted by LOS (OR = 1.3; 95% CI, 1.04–1.5; P = .02).ConclusionsPublic insurance appears to be associated with NURs, while LOS predicts URs after BS. This suggests an important dichotomy within readmissions based on urgency, which has important implications for targeted quality initiatives.     

Reliability of reciprocal isokinetic testing of the knee extensors and flexors

This study was conducted to assess the reliability of torque measurements across different trials and different test sessions. Each trial consisted of three maximal, reciprocal contractions of the knee extensors and flexors at test velocities of 60 and 180 degrees /sec. Three trials were conducted on each of three test sessions, with each session separated by 48 hours. Results indicate that reliability of reciprocal isokinetic testing of the knee can be improved by 1) testing in more than one occasion, 2) testing more than three trials during a single session if testing during more than one session is impossible, and 3) allowing the subject to become familiar with the isokinetic test procedure and to warm up adequately. Data obtained in this study indicated performance variability was predominantly associated with between subject differences and secondarily related to within subject changes over trials and days. Dynamometer calibration remained stable across all test sessions, indicating that the method was reliable for recording torque output during all testing procedures. J Orthop Sports Phys Ther 1991;14(3):121-127.     

Bent helical structure in kinetoplast DNA

We have investigated the unusual physical properties of a restriction fragment of Leishmania tarentolae kinetoplast DNA. A gel-purified fragment comprising slightly more than half of a minicircle was determined by Maxam-Gilbert sequence determination to be 490 base pairs (bp) in length. This fragment has dramatically anomalous electrophoretic behavior; it has an apparent size of 450 bp on a 1% agarose gel but migrates as 1,380 bp on a 12% polyacrylamide gel. However, in gel filtration on Sephacryl S-500, the fragment elutes with an apparent size of 375 bp. Finally, it behaves anomalously in electric dichroism experiments. Field-free rotational relaxation times from transient electric dichroism studies are highly sensitive to effective molecular dimensions. The rotational relaxation time of the kinetoplast fragment is smaller than that of a 309-bp control fragment from pBR322. Because rigorous control experiments rule out the possibility that this fragment is modified, these anomalous properties must be dictated by the sequence itself. Fragment behavior indicates that it has an unusually compact configuration; we propose that this molecule contains a region of systematically bent B-DNA. This model accounts for the fragment's difficulty in snaking through the pores of a polyacrylamide gel, its ease in diffusing into Sephacryl beads, and its smaller rotational relaxation time. Bending of this molecule may be caused by periodicities in the DNA sequence.     

Randomised controlled double blind study of role of recombinant erythropoietin in the prevention of chronic lung disease

AIM—To evaluate the role of recombinant human erythropoietin (R-HuEpo) in reducing iron infusion, which may exacerbate free radical damage, leading to chronic lung disease.METHODS—A multicentre, randomised, placebo controlled, double blind study was carried out in four neonatal intensive care units in Yorkshire. Infants were randomly allocated and received either R-HuEpo (480 U/kg/wk) or placebo by twice weekly subcutaneous injection. The primary outcome measure was the number of days on respiratory support and a secondary outcome the number of blood transfusions required.RESULTS—Forty two very low birthweight (VLBW) infants were randomly allocated. There was little difference in the need for respiratory support one month after randomisation, but subsequently there was a trend towards a reduction in the proportion requiring respiratory support in the R-HuEpo group (difference at three months ?0.50, 95% confidence interval ?1.00, 0.17). During stay in hospital, the median number of blood transfusions was lower for infants in the R-HuEpo group (difference in medians ?2, 95% CI ?4, 0). The study was stopped early because of failure to recruit babies at the expected rate.CONCLUSIONS—R-HuEpo seems to reduce the number of days in oxygen for ill VLBW infants. These data could be used to construct a larger multicentre study to evaluate this effect further.     

Quantitative comparison of intrabrain diffusion in adults and preterm and term neonates and infants

OBJECTIVE: Quantitative measurements of mean water diffusivity (D(av)) were made in human neonates, infants, and adults to assess changes in brain tissue that occur with maturation. SUBJECTS AND METHODS: Values of D(av) were obtained by calculating the average of the diffusion measurements made with diffusion-sensitizing gradients placed along three orthogonal directions. The mean diffusivity, a rotationally invariant determination of apparent diffusion coefficient, was measured in five healthy prematurely born neonates and infants, in 10 healthy term neonates and infants, and in five adults. RESULTS: Values of D(av) were found to decrease with maturation in most parts of the brain. In prematurely born neonates and infants with a postmenstrual age (postgestastional age + postnatal age) under 36 weeks, the average value of D(av) in frontal white matter was 1.90 x 10(-3) mm2 sec(-1). The corresponding value was measured as 1.62 x 10(-3) mm2 sec(-1) in neonates and infants born at term with a postnatal age of no more than 43 days and 0.79 x 10(-3) mm2 sec(-1) in the adult brain. CONCLUSION: Values of D(av) are known to decrease in neonates and young infants in the period immediately after ischemic insult. This decrease and the associated increase in signal intensity seen on diffusion-weighted imaging have been used to monitor ischemic brain injury in neonates and infants. Therefore, the decrease in D(av) that occurs with maturation, which we report in this study, must be considered if quantitative diffusion measurements are used to assess ischemic neonatal brain injury.     

Effects of nursery illumination on frequency of eyelid opening and state in preterm neonates

The behaviour of a group of premature neonates was observed under three conditions of ambient illumination defined as either DARK, LIGHT or BRIGHT (mean intensities: 0.9, 109 and 1370 lux). Trends in the data suggested that increasing the level of illumination resulted in a reduction in the proportion of time spent with eyelids open and of the amount of time spent in awake states. However, these effects were small and in most cases failed to attain statistical significance. Sudden offset of light did however produce a transitory increase in eyelid opening for a period of approximately 60 s that appeared to be unaccompanied by any change of state (P less than 0.001). Irrespective of illumination condition, the infants' behaviour was characterized by prolonged periods of eyelid closure which were significantly greater for the lower eye (in mattress contact, mean lid closure = 96.2%) compared to the upper eye (no mattress contact, mean lid closure = 88.25%). The prolonged occurrences of eyelid closure are discussed in relation to visual development and phototoxicity.     

Birth size in Indian ethnic subgroups born in Britain.

Comparison in size at birth was made among Indian mothers of Hindu, Sikh, and Moslem origin living in Leicester and their infants, and white mothers and their infants. White infants were significantly heavier than infants from all Asian subgroups studied and had larger heads. Sikh babies were significantly longer and heavier than Moslem and Hindu babies, and in some respects were more comparable to white infants than their Indian peers. There were no important differences between the Moslem and Hindu babies.