Search PubMed⌕ Search

Biomedical subjects

P Helms

Publications and source records attributed to P Helms.

102 records · Page 6Linked to original sources
PubMedDate not supplied

The accuracy of esophageal pressure measurements in convalescent and sick intubated infants.

Assessment of the esophageal pressure technique for measuring dynamic lung compliance (Cdyn) showed that accurate results were obtained in only 5 of 15 studies of sick intubated infants, whereas they were obtained in 6 of 6 studies of convalescent nonintubated infants. In sick infants, inaccuracy was due to large variations in esophageal pressure change (delta Pes) at different esophageal depths and difficulties validating Pes using the occlusion test. Methods of assessing lung stiffness that depend on the measurement of esophageal pressure are unreliable and should not be used in sick intubated infants.

Bronchopulmonary Dysplasia↗
PubMedDate not supplied

Total respiratory compliance and functional residual capacity in young children.

Measurements of total compliance of the respiratory system (CRS) by the weighted spirometer technique and functional residual capacity (FRC) by helium gas dilution were attempted in 63 healthy children (aged 2 to 7 years). Weighted spirometry was well tolerated in all but six children, and FRC measurements were successful in 42. Both measurements were reproducible and not affected by posture. Good correlations were found between CRS and height (r = 0.73) and age (r = 0.83) as well as between FRC and height (r = 0.83) and age (r = 0.74). No differences were found between boys and girls. CRS also correlated significantly with FRC (r = 0.67). In five children with cystic fibrosis, measurements of CRS, FRC and specific compliance correlated with disease severity. Our data suggest these well-tolerated techniques may provide a useful means to distinguish the effects of disease from those of growth.

Age Factors↗
PubMedDate not supplied

Improved accuracy of the occlusion technique for assessing total respiratory compliance in infants.

The occlusion technique to measure total respiratory system compliance (Cocc) was used in 28 sedated infants with a variety of cardiopulmonary diseases and 14 anaesthetised infants during the first 2 years of life. In this report, we describe some of the potential problems in the technique and how to avoid them. Invalidation of the occlusion technique because of consistent failure to relax during brief airway occlusions occurred in only four of 42 infants despite the fact that only four infants were studied during the first month of life and 17 were between 12 and 26 months old. The technique was invalidated in two intubated infants because of persistent leaks around the endotracheal tube. In the remaining 36 infants, data sometimes had to be excluded as a result of instability and end-expiratory volume, intermittent leaks, or failure to relax during occlusions performed at low lung volumes or during inspiration. However, by performing 15-25 occlusions per infant, it was possible to obtain sufficient reliable data for accurate analysis of Cocc in all these infants. Providing that the potential errors and limitations of the occlusion technique are recognized, it appears to be applicable to a wide range of healthy and sick infants.

Forced Expiratory Flow Rates↗
PubMedDate not supplied

Comparison of the occlusion and inflation techniques for measuring total respiratory compliance in sick, intubated infants.

Respiratory system compliance (Crs) can be used to assess lung stiffness in sick, intubated infants, avoiding the use of an esophageal balloon. Crs was assessed in a group of 15 sick, intubated infants using the occlusion and inflation techniques. The occlusion technique gave satisfactory results in 13 infants. Apneic pauses following occlusion were obtained in infants up to 10 months of age. Satisfactory measurements of Crs were obtained in all 15 infants using the inflation technique, but difficulty was experienced in obtaining data over the tidal volume range in three of them. A close agreement was found between the two methods of measuring Crs in the ten infants in whom a direct comparison was possible.

Lung Compliance↗
PubMedDate not supplied

Menarche in intensively trained gymnasts, swimmers and tennis players.

It has been hypothesized that young athletes, undertaking intensive training, have delayed menarche due to the effects of training at an early age, although it is known that other genetic and environmental factors contribute to this observed later menarche. As part of a longitudinal study of the effects of intensive training during puberty and adolescence we investigated age of menarche in 222 athletes and their mothers. All the sports studied (gymnastics, swimming and tennis) had later mean ages of menarche (14.3, 13.3 and 13.2 years respectively) than the previously reported UK reference value of 13.00 years. A positive correlation was found between menarcheal age in mothers and daughters (r = 0.27, p < 0.01). Analysis of covariance, using maternal menarcheal age, socioeconomic group, duration of training and type of sport, confirmed that maternal menarcheal age and type of sport were having a significant influence on subject's age of menarche. As maternal menarcheal age and sport were the best predictors of menarcheal age in the athletes we studied, it would appear that menarche was intrinsically late rather than delayed. This suggests that some form of sport-specific selection may have occurred. It therefore seems likely that late maturation of gymnasts contributes to a girl's decision to continue participating in the sport rather than intensive training delaying menarche.

Adolescent↗
PubMedDate not supplied

Growth and development of male gymnasts, swimmers, soccer and tennis players: a longitudinal study.

Elite adult athletes are known to have physical and physiological characteristics specifically suited to their sport. However, it is not clear whether the observed adult differences arise because of training or whether the sport selects the individual with the appropriate characteristics. The purpose of this prospective study was to compare and contrast the physical development of young athletes (8-19 years), and in so doing provide a possible response to this question. Development of anthropometric characteristics and sexual maturation were assessed in a group of 232 male athletes for three consecutive years. Parental heights were used to predict target heights. The subjects were a randomly selected group of young British athletes, from four sports: soccer, gymnastics, swimming and tennis. Using a linked longitudinal cohort study design (age cohorts 8, 10, 12, 14 and 16 years) it was possible to estimate a consecutive 11-year development pattern, over the 3-year testing period. The adjusted mean (ANCOVA) height, accounting for age and pubertal status, of male swimmers (161.6 +/- 0.6 cm) was found to be significantly greater (p < 0.01) than gymnasts (150.7 +/- 0.8 cm) and soccer players (158.7 +/- 0.6 cm), and their adjusted mean body mass (51.3 +/- 0.6 kg) significantly greater (p < 0.01) than the other groups. When testicular volumes were compared, it was found that swimmers had significantly larger volumes than gymnasts and tennis players from 14 to 16 years of age (p < 0.05). Gymnasts' growth curve of testis size was characteristic of late maturers, the swimmers' curve was characteristic of early maturers. As all the young athletes started training prior to puberty the observed late sexual maturation of gymnasts and early maturation of swimmers suggests some form of sports-specific selection. Training did not appear to have affected these young athletes' growth and development; rather their continued success in sport appeared to be related to inherited traits.

Adolescent↗
PubMedDate not supplied

Is the objective assessment of cerebral palsy gait reproducible?

It is important to determine the reproducibility of objective measures of gait in children with motor disorders in order that the effect of interventions to improve gait can be monitored. Data for walking velocity and vertical ground reaction force expressed as a percentage of body weight were collected from 15 normal children and 11 with spastic cerebral palsy. Five recordings were obtained for each foot of each child on 3 consecutive days, and calculations of variability made for each set of five recordings. Children with cerebral palsy had slower walking velocities and greater ground reaction force values, and both these parameters had low intraindividual variation for both normal children and those with cerebral palsy (coefficients of variation < 12.5%). This good reproducibility applied to intrasubject and intraday variability; no learning effect was seen over 3 days' recordings. There was no significant difference in variability whether the first three recordings or all five were used. These techniques of gait measurement in children have good reproducibility and a potential role in the objective assessment of medical and surgical interventions.

Cerebral Palsy↗
PubMedDate not supplied

PACE project: object-orientated modelling of paediatric practice.

The need for useful clinical support based on integrated computerized systems is now well recognized. To build systems desired by busy clinicians requires accurate specifications. These specifications in turn require rigorous descriptions of the processes to be automated in a form which is understandable and unambiguous to both clinician and computer scientist. Despite these requirements communication between suppliers and users of computer systems often is poor. Detailed descriptions of health care with particular reference to child health were developed with an object-orientated technique. These descriptions take the form of conceptual models of the basic health care activities (evidence collection, assessing, planning and implementing management) and more specific departmental activities pertaining to paediatric intensive care, accident and emergency, and cystic fibrosis management. We have learned that once a modelling team becomes competent in applying the technique, object-orientated modelling can be a powerful tool for the description of complex processes such as those involved in present-day health care.

Decision Support Techniques↗
PubMedDate not supplied

Basic health care functions: an object-orientated analysis.

All clinical activities carried out by health care professionals can be seen as examples of what we have called the basic health care functions. These are collecting information concerning the patient, assessing the patient in the light of the information gathered, and then planning and administering the care which is deemed necessary. For a computerized clinical support system to be helpful to clinicians it is essential that the information and computer scientists responsible for building such systems have clear and detailed descriptions of the activities carried out by their clinical colleagues. One method of bridging this communication gap is object-orientated modelling. In this paper we present an object-orientated analysis of the basic health care functions, thus establishing a generic model on which descriptions of more specific clinical situations can be based.

Decision Support Techniques↗