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Biomedical subjects

J Levett

Publications and source records attributed to J Levett.

18 recordsLinked to original sources
PubMed2001

Effect of sleep position on apnea and bradycardia in high-risk infants.

OBJECTIVE: The purpose of this investigation was to investigate, in high-risk infants, the occurrence of abnormalities in documented monitor downloads during the side versus prone position. STUDY DESIGN: Forty infants admitted to the A. I. duPont Hospital for Children with diagnoses associated with sudden infant death syndrome were included in this investigation. During an overnight hospitalization, infants were placed on home apnea monitors, with computer memory to capture alarms for apnea > 20 seconds, age-defined bradycardia, and tachycardia. Infants were studied for 12 hours. Each infant was assigned to 6 hours of prone and side during the 12-hour period, with order of position randomly assigned by random number generation. Differences between the two positions in alarm frequency and significant events, as determined by a blinded interpreting physician were analyzed by Fisher exact test, with p < 0.05. Power analysis necessitated 20 patients in each group, with beta error of 0.2. RESULTS: Eleven episodes of apnea occurred in the prone position, and 16 in the side position (p = NS). The mean numbers of apnea events per tracing in the prone position was 0.27 +/- 0.84 and 0.39 +/- 1.1 in the side position (p = 0.58). The mean number of bradycardia events per tracing in the prone position was 0.44 +/- 1.45 and 0.49 +/- 1.94 in the side position (p = 0.9). CONCLUSION: Clinicians need to be cautious when recommending the side or prone position in this group of high-risk infants. The results in this investigation provide support for the Back to Sleep Campaign recommendations to be applied, not only to healthy term infants, but higher risk infants as well. Studies of the high-risk infant in the supine position are warranted.

Bradycardia↗
PubMed1985

Primary hydatid disease of the infratemporal fossa and the parotid gland.

Hydatid disease should be considered in the differential diagnosis of lesions causing swelling of the parotid area or exophthalmos in patients originating from countries where the incidence of the disease is high. An unusual case of hydatid disease located in the infratemporal fossa and the anterior parotid region is presented. Computed Tomography is a valuable tool for establishment of the diagnosis, before any surgical approach to the lesion is initiated and for postoperative follow-up and evaluation.

Adolescent↗
PubMed1979

Oscillatory potentials in the electroretinogram.

This paper presents an analog circuit model of the electroretinogram b-wave and subsequent oscillations postulated to result from the depolarization of the retinal glial cells produced by potassium. The system is described by a second-order equation which oscillates under conditions of light adaptation. With dark adaptation the oscillations undergo attenuation. Light falling on the retina ultimately liberates potassium ions and this ionic current is considered to be the system input. A first approximation is an exponentially decaying current which varies depending upon light background, flash intensity and various drug manipulations. This model is a reasonable fit to the electroretinogram over considerable light background levels and is suggested as a useful tool in the study of various pharmacological effects on retinal electrophysiology.

Animals↗
PubMed1977

Voluntary eye movements and alcohol.

Human voluntary horizontal eye-movements are studied prior and subsequent to the ingestion of alcohol. Such movements are important, especially during reading and driving. Infrared monitoring techniques were employed to record eye movements and eye-movement latency histograms were tabulated. Blood alcohol levels were continually monitored. Alcohol increases eye-movement latency but the maximum latency occurred in most cases at different elapsed times from the time of maximum blood alcohol level. In general, a roughly 20% increase in latency occurs subsequent to alcohol. Whether this added delay is a result of a general depression of the oculomotor system or a specific increase in some oculomotor computing element is unresolved. Within the limits of our experimentation, there was no difference between latency change observed in moderate and heavy drinkers.

Ethanol↗
PubMedDate not supplied

Infant sleep position. Nursing practice and knowledge.

PURPOSE: (1) to examine the extent to which maternal/child health nurses caring for children accept the American Academy of Pediatrics recommendations on infant sleep position, (2) to determine if nurses are practicing according to the AAP recommendations, and (3) to determine the type of bedding utilized in the two institutions for infants. METHODS: Descriptive survey using 103 nurses in 2 institutions, and an observational assessment of nurses' practice. RESULTS: Findings revealed that 97% of the nursing staff were aware of the AAP recommendations, although only 67% agreed with the recommendations. The observational component of the investigation evaluated the sleep position during hospitalization of 206 infants < 6 months old on both the pediatric and maternity units of the two institutions. Fifty-five percent of the infants were observed to be in the side-lying position, 29% in the recommended supine (back) position, and 16% in the prone (abdomen) sleeping position. The recommended firm bedding was observed with 63% of the infants, whereas the remainder of the infants were observed to be on foam mattresses, extra blankets, or gel packs. CLINICAL IMPLICATIONS: Because side sleeping position was observed in the majority of infants, and one-third of the nurses queried disagreed with the AAP recommendations, education of nurses about Sudden Infant Death Syndrome prevention through "Back to Sleep" is still necessary.

Bedding and Linens↗
PubMedDate not supplied

The first man/machine interaction in medicine: the pulsilogium of Sanctorius.

This article, published in lieu of the customary feature, artifact, describes one of the earliest medical devices--a device to measure pulse rate. A close examination of the pulsilogium of Sanctorius of Padua (1561--1636) reveals it to be something more than the first measuring device in medical history; it is also the first man/machine system in medicine. Using a systems approach, pulsilogium and physician interaction is found to contain important dynamic characteristics. The device is operated in a negative feedback mode, employs the concept of transduction, and measures pulse through another dimension--length. More than 100 years after its invention, the pulsilogium found useful application by de la Croix in measurements of cardiac function during "electrification."

History, 16th Century↗