Response of lower esophageal contractility to changing concentrations of halothane or isoflurane: A multicenter study

A multiple-center study was performed to determine the relationship between lower esophageal contractility, clinical signs, and anesthetic concentration as expressed by minimum alveolar concentration (MAC). One hundred four American Society of Anesthesiologists Class I through III patients were exposed to isoflurane (with and without nitrous oxide) or halothane in concentrations of 0.5, 1.0, and 1.5 MAC. Heart rate and systolic blood pressure were continuously monitored. Both the amplitude and frequency of spontaneous and provoked lower esophageal contractions were measured in situ by using a 24-F probe equipped with provoking and measuring balloons. Combined results demonstrated statistically significant correlations (P<0.001) between lower esophageal contractility and MAC. Spontaneous lower esophageal contractions decreased from 1.10±0.12 (SEM) contractions per minute (0.5 MAC) to 0.42±0.05 (1 MAC) to 0.18±0.05 (1.5 MAC). Provoked lower esophageal contractility values decreased from 45±4 mm Hg (0.5 MAC) to 29±3 (1 MAC) to 19±2 (1.5 MAC). Heart rate changes did not correlate with MAC, and systolic blood pressure correlated in only one of three centers. Intracenter and intercenter analyses failed to demonstrate a significant relationship between lower esophageal contractility and heart rate or systolic blood pressure. No intracenter differences in either amplitude or frequency of lower esophageal contractions were observed, despite differences in volatile agents, induction techniques and agents, patient populations, and duration of anesthesia. Our studies indicate that lower esophageal contractility may be an indicator of anesthetic depth as reflected by MAC, but further studies are needed to quantify the effects of surgical stimulus, intravenous anesthetics, vasodilators, anticholinergics, calcium channel blockers, beta-adrenergic agonists, and the presence of a nasogastric tube.     

Reference values for nucleosides and nucleobases in cerebrospinal fluid of children

Disturbances in the metabolism of purines and pyrimidines in neurologically affected patients can be reflected by aberrant concentrations of nucleosides and nucleobases in cerebrospinal fluid (CSF). However, normal values, especially for children at different ages, are lacking. We collected 1000 specimens of CSF from subjects ranging in age from newborn to 18 years, who were undergoing a diagnostic lumbar puncture for several clinical indications. Of these, 78 samples could be used retrospectively as a reference according to our criteria. The analyses were performed with a modified HPLC procedure. None of the substances shows age-dependency except uridine and uric acid. Uridine increases with age, and uric acid increases with age in boys older than 12 years.     

Should nurses be studying bioscience? A discussion paper

The growth of bioscience knowledge over the last two decades has increased the potential benefits of scientifically based patient care by contributing to the theory of clinical care. However, there is little evidence that knowledge, derived from the human biosciences is being fully incorporated into nursing theory and practice.Nursing has developed its own unique professional body of knowledge, heavily influenced by behavioural science. If nursing theory leans towards behavioural science, but practice is devoted to problems of biological disturbance, nursing may be facing a widening theory-practice gap, greater than other professions. The theory-practice gap in nursing may be widened by the exclusion of bioscience from nursing theory. Nurses' relative disinterest in the natural sciences can be attributed both to sociological reasons and to problems stemming from the symbol-object dichotomy that recur in the teaching of natural sciences. Reflection on practice and examination of education method are suggested as strategies for re-introducing bioscience into nursing theory and practice. A challenge facing nurse educators is the integration of biological science into the nurses' conceptual ecologies. For, if nursing fails to make bioscience its own, much of the clinical welfare of patients will become a medical monopoly.     

Parity and bone mineral density in middle-aged women

A retrospective study was carried out to determine the relationship between parity and bone mineral density (BMD) in middle-aged women. Eight hundred and twenty-five woman aged 41–76 years were recruited from four general practice registers in Cambridge. Subjects were unselected as to their health status. Each subject completed a detailed health questionnaire. Participation rate was 50%. The main outcome measure was BMD measured at the spine (L2–4,n=825) and hip (neck, intertrochanter and Ward's triangle;n=817) by dual-energy X-ray absorptiometry (DXA) using the Hologic QDR-1000 densitometer. It was found that the unadjusted mean BMD was significantly higher at all sites among the parous women (p=0.031 to <0.00001), and remained significantly higher at the femoral neck (p=0.025), intertrochanter (p=0.001) and Ward's triangle (p=0.045) after adjusting for age and body mass index (BMI). Similar findings were seen after stratifying for potential confounding variables. There was a consistent upward trend of BMD with increasing parity at all sites. Parity remained a significant independent predictor of BMD at all sites after controlling for age, BMI, menopausal status, oral contraceptive and hormone replacement therapy use, smoking status and breast-feeding status in multiple linear regression analyses. There was, on average, a 1.0% increase in BMD per live birth. Our findings therefore suggest a positive relationship between parity and bone mass.     

The synchronization of respiration and swallow sounds with videofluoroscopy during swallowing

Simultaneous recording of adult subjects sipping small amounts of fluid from a cup have been obtained by videofluoroscopy together with feeding respiratory patterns and swallow sounds from the Exeter Dysphagia Assessment Technique (EDAT). These allowed visual representations of respiration and swallow sounds to be superimposed on a videofluoroscopy recording using a split-screen technique. Sequentially numbered, 1/50 sec, half-frame photographic prints were examined and schematic drawings of the relevant radiographs were made. These were superimposed on to the actual EDAT printed chart of the same swallow event, theri exact time relationship with respiration and cervical swallow sounds being preserved. The results allow events in the barium videofluoroscopy to be related to events in the feeding respiratory pattern and swallow sounds recorded by EDAT.