ABSTRACT
UNLABELLED: We performed a retrospective study of twin pairs under 36 weeks gestation admitted to a regional neonatal unit over a three year period to determine if the larger twin of a twin pair is at increased risk of respiratory distress in the immediate postnatal period compared to the smaller twin. Gestation, gender, birth weight, mode and reason for delivery, birth order, and Apgar at 5 minutes were correlated with the need for added oxygen at 4 hours, the need for ventilation, oxygen requirement at 28 days and mortality. One hundred and twenty-four twin pairs were analyzed with a median gestation of 31 weeks (range 23-35). There were 47 female-female pairs, 40 male-male pairs and 37 mixed pairs. Multiple logistic regression revealed no significant increased risk for ventilation in male, heavier or second twins. The need for oxygen at 4 hours was strongly associated with being male and being the second twin, but not with being the heavier twin. However, on analysis of twins of 28 weeks gestation or above a significant association was found between a persisting oxygen requirement at 4 hours and being male (OR 2.2; 95% CI 1.15-4.16), being the heavier twin (OR 1.9; 95% CI 1.03-3.46), and being the second twin (OR 2.7; 95% CI 1.48-4.99). No association was found between mortality and being male, and being the second or smaller twins. CONCLUSION: Heavier twins above 28 weeks gestation are at increased risk of short term mild respiratory problems following delivery compared to lighter twins at the same gestation. This is not as strong a factor as birth order or male gender, but it is important to be aware of this in antenatal counselling of the parents as the smaller twin is usually perceived to be at greater risk of morbidity.
Subject(s)
Birth Weight , Diseases in Twins , Infant, Premature , Respiratory Distress Syndrome, Newborn/epidemiology , Apgar Score , Birth Order , Cesarean Section , Delivery, Obstetric/methods , Female , Gestational Age , Humans , Infant Mortality , Infant, Newborn , Logistic Models , Male , Obstetric Labor, Premature , Oxygen/administration & dosage , Oxygen/therapeutic use , Pregnancy , Respiration, Artificial , Retrospective Studies , Risk Factors , Sex CharacteristicsSubject(s)
Absenteeism , Employment/economics , Employment/legislation & jurisprudence , Nurse Anesthetists/economics , Nurse Anesthetists/legislation & jurisprudence , Salaries and Fringe Benefits/economics , Salaries and Fringe Benefits/legislation & jurisprudence , Humans , Professional Competence/economics , Professional Competence/legislation & jurisprudence , United StatesSubject(s)
Health , Physical Fitness , Adult , Aged , Agriculture , Humans , Male , Middle Aged , Ontario , Rural Health , Sampling Studies , Urban HealthABSTRACT
Two studies examined perception of briefly presented (100-msec.) strings of letters. In Study One, 20 subjects were presented horizontal 5-letter strings in the left, central, and right visual fields. These were compared with 5-letter vertical strings presented centrally in the lower, central, and upper visual fields. Similar within-string patterns were found for all presentations. Between strings there was a typical right over left visual-field advantage in accuracy of report for horizontal strings. There was no equivalent lower over upper visual-field advantage for vertical strings. In Study Two, 24 subjects were presented vertical strings in the right and left visual fields, vertical strings in the upper and lower visual fields, and horizontal strings in the right and left visual fields. A post-stimulus cueing technique for single letters was used. Between-strings, the same right over left visual-field advantage for horizontal strings was noted but not for vertical strings. Between strings no advantage for lower over upper visual fields was found. An interaction for within-string patterns and visual field was found for vertical strings presented in the upper and lower visual fields. These results are explained in terms of an interaction between scanning and masking effects depending upon orientation and visual field.
Subject(s)
Dominance, Cerebral , Form Perception , Orientation , Adult , Discrimination Learning , Female , Humans , Male , Reading , Visual FieldsABSTRACT
Conduction velocity, absolute refractory period, and subnormal conduction period measures of the right ulnar motor nerve were obtained during a simple reaction time task. 6 young, healthy, right-arm dominant male subjects were tested following 30 min. exposure in ambient (20 degrees C) and hot (36 degrees C) room air conditions. Motor and premotor components of fractionated reaction time were tested on the same arm. Oral, right forearm skin and a four-site mean skin temperature were monitored. During heat exposure, forearm skin temperature increased 4.7 degrees C and mean skin temperature 2.9 degrees C. Oral temperature did not alter. Conduction velocity increased 11.4%, absolute refractory period decreased 22.7%, and subnormal conduction period decreased 14.1% in the hot condition. Concomitantly, a 5.2% increase in premotor reaction time and 12.2% decrease in motor reaction time were observed. Total RT did not alter significantly. It was concluded that different component parts of reaction time were differentially influenced by exposure to heat.
Subject(s)
Hot Temperature , Reaction Time/physiology , Ulnar Nerve/physiology , Adult , Humans , Male , Neural Conduction , Neural Pathways/physiology , Refractory Period, Electrophysiological , Skin Temperature , Synaptic TransmissionABSTRACT
A small change in brick dimensions resulted in an increase in the perceived work-load of men loading and unloading pallets of bricks by hand. A laboratory study indicated that the change in brick dimensions required changes in grip pattern in order to unload bricks at the same rate, moving the same number at a time. These changed grip patterns resulted in increased upper body movement, increased chest-muscle activity and higher heart rates. These differences were reflected in higher subjective ratings of fatigue.
