Is the IV obstructed or infiltrated? A simple clinical test

Objective. The objective of our study was to determine if clinical observation of pressure-flow relationships (PFR) can differentiate between partial external obstruction (obstruction) and infiltration as a cause of poor performance of gravity-fed infusions.Methods. A total of 24 patients with functional intravenous cannulae in situ had obstruction simulated by the application of a tourniquet proximal to the cannula. The change in flow (F) for a discrete change in pressure (P) was determined in each case by counting drop rates at two different elevations of the fluid reservoir level, 10 cm apart. The same process was repeated in 15 patients in whom the cannula was in an extra vascular location (infiltration). Three sizes of cannula—16-gauge, 18-gauge, and 20-gauge—were examined, with equal distribution of sizes in each group. The effect on flow rates of inflating a blood pressure (BP) cuff proximally on the cannulated limb was assessed. The ratio P/F is the total resistance of the infusion system, and by subtracting known values for resistance of infusion tubing and cannula, the venous or tissue resistance was calculated.Results. There was a statistically significant difference between the change in flow for obstructed compared with infiltrated cannulae for the same change in pressure for each cannula size. The mean venous resistance was 23 mm Hg/L/hr, while that of tissue was 280 mm Hg/L/hr, with no overlap between groups. There was no effect on flow rate with blood pressure cuff inflation in the infiltrated group whereas flow progressively fell in the obstructed group.Conclusions. Clinical observation of PFRs in poorly functioning gravity-fed IV infusions can assist in detecting infiltration as a cause. Inflation of a blood pressure cuff will further impair flow where the cannula is intravascular, but will have no effect in an extravascular location.     

Low maternal weight gain in the second or third trimester increases the risk for intrauterine growth retardation

Low maternal weight gain during pregnancy has been suggested as a cause of intrauterine growth retardation (IUGR). However, pregnancy weight gain and fetal growth vary greatly throughout pregnancy. We examined the relationship between maternal weight gain in individual trimesters to the risk of IUGR in 10,696 women enrolled in the National Collaborative Perinatal Project (NCPP) and the Child Health and Development Study (CHDS). Low weight gain was defined as <-0.1 kg/wk for the first trimester and <0.3 kg/wk for the second and third trimester. IUGR was defined as a birth weight <2500 g in full-term infants. Low weight gain in the first trimester was not associated with an increased risk of IUGR. After controlling for confounding factors (maternal height, body mass index, parity, race, toxemia, diabetes), low weight gain in the second trimester was associated with a relative risk of IUGR of 1.8 (1.3-2.6) in the NCPP cohort and 2.6 (1.6-4.1) in the CHDS cohort. Similarly, low weight gain in the third trimester was associated with a relative risk of IUGR of 1.7 (1.3-2.3) in the NCPP cohort and 2.5 (1.7-3.8) in the CHDS cohort. After correcting for weight gain in other trimesters, this increased risk remained. Increased risk of IUGR was observed with low second and third trimester weight gain across the spectrum of maternal body mass index. The risk of low weight gain in the second or third trimester was significantly lower in teenagers and significantly greater in overweight women and women aged 35 y or older. Low weight gain in either the second or third trimester was associated with a significantly greater risk of intrauterine growth retardation in two distinct cohorts. We conclude that increased awareness of maternal weight gain in mid and late pregnancy is critical to identifying infants at risk for IUGR.     

Brain-tissue accumulation of fluorescent age pigments in four poeciliid fishes (cyprinodontiformes) and the estimation of "biological age"

The concept of an intrinsic "biological age" or "physiological age" is very important in comparative ecological and evolutionary studies, but its implementation has been problematic. Although many authors have discussed the importance of intrinsic measures of age over the past 75 years, only Reiss (1989 ) has proposed an operational definition in terms of cumulative metabolism; however, Reiss' measure cannot be easily applied to assessing the age of individual organisms. Measurement of the level of accumulation of fluorescent age pigments (particularly lipofuscins) in post-mitotic tissues, which seems to occur at a rate proportional to cumulative metabolism, in principle provides a mechanism for estimating the biological age of individual organisms. This study has shown that brain-tissue FAP levels vary in direct proportion to chronological age and body size within four species of poeciliid fishes, and has documented interspecific differences in rate of accumulation of fluorescent age pigments, differences that seem to be a function of the degrees of relatedness. Rather than proposing that FAP level by itself be used as a measure of biological age, however, I propose that it be used in conjunction with other estimates, such as chronological age and body size, to derive a composite "age factor."     

Mortality of persons with developmental disabilities after transfer into community care: a 1996 update

More than 2,000 persons with developmental disabilities have recently been transferred from California institutions into community care. Using data on 1,878 clients moved between April 1993 and December 1995, Strauss et al. (1998) found a corresponding increase in mortality rates. In the present report we update that study by analyzing 1996 data. There were 36 deaths, an 88% increase in risk-adjusted mortality over that expected in institutions, p < .01. We again found that persons transferred later were at higher risk than those moving earlier, even after adjustment for differences in risk profiles. In the highest functioning group, the community mortality rate was tripled. Death certificate information was also analyzed.     

Detection and typing of human papillomavirus DNA in paired urine and cervical scrapes

The prevalence of human papillomavirus (HPV) in paired cervical scrape and urine specimens from 144 women attending a clinic for genitourinary medicine was determined by polymerase chain reaction (PCR) and nested PCR, using degenerate and general primer pairs localized within the L1 region. HPV typing was by restriction fragment length polymorphism (RFLP), type-specific PCR (HPV 6, 11, 16, 18, 33), and partial DNA sequencing of PCR products. HPV DNA was detected in 114 (84%) women. HPV DNA was detected in the specimens of 58 patients after amplification with MY09/MY11 primers and in a further 54 patients after nested PCR with the GP5 + /GP6 + primers. A total of 106/136 (78%) of women had HPV DNA positive cervical scrapes and 89 (65%) had HPV DNA positive urine specimens. Both the urine and cervical specimens of 81 women were positive. In 25 women HPV DNA was detected in the cervical specimen only, and in 8 women HPV DNA was detected in the urine specimens only. A total of 108 specimens from 75 patients were typed. For 33 patients HPV typing was achieved in both the cervical and the urine specimens and 19 women had identical types in paired specimens. Multiple HPV infections could be detected in 15 (20%) of 75 women where either the cervical and urine specimen or both of the specimens could be typed. More then one HPV type was found in 8 specimens and from multiple sites (cervix and urinary tract) in the same patients on 7 occasions. The results of this study indicate that the detection of HPVs in the urogenital tract can be maximised through the testing of both cervical scrapes and urine specimens in conjunction with the use of a nested PCR to increase the sensitivity of HPV DNA detection. Also, urine cannot be a direct substitute for a cervical scrape as different HPV types are often detected in the urine compared with those detected in the cervix.     

Effect of increased atmospheric pressure on radial keratotomy

PURPOSE: To evaluate the effect of increased atmospheric pressure on visual acuity in patients who have had radial keratotomy (RK). SETTING: Long Beach Memorial Medical Center, Long Beach, California, USA. METHODS: This controlled clinical study comprised 4 eyes that had RK and 4 control eyes that were age and sex matched. All patients had prehyperbaric chamber examinations consisting of manifest and cycloplegic refractions, intraocular pressure (IOP), keratometry, and corneal pachymetry. They were then placed into the hyperbaric chamber for 1 hour. Immediately after the patients were removed from the chamber, the examinations were performed again. RESULTS: No statistically significant changes in visual acuity, refractive error, IOP, keratometry, or pachymetry occurred in the 2 groups. CONCLUSION: The results of this study indicate that, unlike at high altitudes, RK is stable at increased atmospheric pressure. This suggests that RK patients can engage in recreational scuba diving without encountering deleterious visual changes.     

Inflammatory mechanisms in Alzheimer's disease

In recent years many studies have indicated an involvement of inflammatory mechanisms in Alzheimer's disease (AD). Acute-phase proteins such as 1-antichymotrypsin and c-reactive protein, elements of the complement system, and activated microglial and astroglial cells are consistently found in brains of AD patients. Most importantly, also cytokines such as interleukin-6 (IL-6) have been detected in the cortices of AD patients, indicating a local activation of components of the unspecific inflammatory system. Up to now it has remained unclear whether inflammatory mechanisms represent a primary event or only an unspecific reaction to brain tissue damage. Therefore, we investigated whether IL-6 immunoreactivity could be found in plaques prior to the onset of neuritic changes, or whether the presence of this cytokine is restricted to later stages of plaque pathology. we confirmed our previous observation that IL-6 is detectable in a significant proportion of plaques in the brains of demented patients. In AD patients IL-6 was found in diffuse plaques in a significant higher ratio as would have been expected from a random distribution of IL-6 among all plaque types. This observation suggests that IL-6 may precede neuritic changes, and that immunological mechanism may be involved both in the transformation from diffuse to neuritic plaques in AD and in the development of dementia.