Doing it right the first time: quality improvement and the contaminant blood culture.

The aim of the project was to determine whether the rate of contaminant blood cultures could be reduced by using a team of dedicated phlebotomists. Comparisons were made between adult patients requiring blood cultures for suspected bacteremia on medical and surgical units before and after the introduction and withdrawal of a dedicated blood culture team. The results showed that a significant reduction in the contaminant blood culture rate was achieved by the blood culture team (P < 0.001; chi(2) test). Therefore, in our experience, the rate of contaminant blood cultures can be reduced in a teaching hospital by using a team of dedicated phlebotomists. Calculations made with our data and those published by others suggest that cost savings from reducing false-positive blood cultures are greater than the cost of the blood culture team.     

Attentional demands of continuously monitoring orientation using vestibular information.

The aim of this series of experiments was to determine whether attention is normally required for continuously processing vestibular information concerning orientation, or is required only when orientation is disrupted (eg by vestibular dysfunction or by conflicting visual and vestibular orientation cues). In the first two studies, healthy subjects were passively oscillated, and indicated when they perceived they were passing through their starting position. There was only weak evidence for interference between performance on this 'continuous orientation monitoring task' and on concurrent mental tasks. However, a third study showed that when patients with vestibular imbalance carried out the continuous orientation monitoring task their performance on a concurrent mental arithmetic task was substantially impaired. This dual task interference was correlated with inaccuracy in judging orientation on the continuous orientation monitoring task, which in turn correlated with severity of recent vestibular symptomatology (assessed by questionnaire). In a fourth experiment, disorientation was induced in healthy subjects by rotating the visual field about the line of sight. Bidirectional interference was observed between monitoring orientation (assessed by accuracy in setting a rod to the perceived vertical) and performance of an arithmetic task. Dual task interference was correlated with baseline levels of disorientation induced by the visual field, as indicated by inaccuracy in judging the visual vertical. These findings suggest that monitoring orientation makes significant demands upon cortical processing resources when disorientation is induced, whether the disorientation results from deficient sensory functioning or from ambiguous perceptual information.     

Detection of the Glanzmann's thrombasthenia mutations in Arab and Iraqi-Jewish patients by polymerase chain reaction and restriction analysis of blood or urine samples.

Severe Glanzmann's thrombasthenia is relatively frequent in Iraqi-Jews and Arabs residing in Israel. We have recently described the mutations responsible for the disease in Iraqi-Jews--an 11 base pair deletion in exon 12 of the glycoprotein IIIa gene, and in Arabs--a 13 base pair deletion at the AG acceptor splice site of exon 4 on the glycoprotein IIb gene. In this communication we show that the Iraqi-Jewish mutation can be identified directly by polymerase chain reaction and gel electrophoresis. With specially designed oligonucleotide primers encompassing the mutation site, an 80 base pair segment amplified in healthy controls was clearly distinguished from the 69 base pair segment produced in patients. Patients from 11 unrelated Iraqi-Jewish families had the same mutation. The Arab mutation was identified by first amplifying a DNA segment consisting of 312 base pairs in controls and of 299 base pairs in patients, and then digestion by a restriction enzyme Stu-1, which recognizes a site that is absent in the mutant gene. In controls the 312 bp segment was digested into 235 and 77 bp fragments, while in patients there was no change in the size of the amplified 299 bp segment. The mutation was found in patients from 3 out of 5 unrelated Arab families. Both Iraqi-Jewish and Arab mutations were detectable in DNA extracted from blood and urine samples. The described simple methods of identifying the mutations should be useful for detection of the numerous potential carriers among the affected kindreds and for prenatal diagnosis using DNA extracted from chorionic villi samples.     

Time related bias in longitudinal studies using dual photon absorptiometry.

Examining the bone mineral density (BMD's) slope of patients regularly followed in our department, we observed recently that the group of patients who had their last BMD during the last 6 months of 1989, had a different slope than patients who had their last BMD during the following 6 months. In order to investigate if a small time-related bias of measurement, unsuspected by the former quality control investigations, could exist, we performed the following analyses. A regression equation between BMD and time was calculated and a slope was obtained for 95 women who had been followed for at least 3 yr and had had at least 3 BMD measurements during that time. The women were divided in 3 groups according to when the last BMD measurement had been performed (July-December 1989, January-June 1990 or July-December 1990). The slopes of the 3 groups of patients were compared. For each value of BMD of every patient, a predicted BMD (BMDp) was calculated using the regression equation and the relative difference (RD) between BMDp and BMD was calculated and analysed in relation to time. There was a significant difference (p < 0.05) between the slopes of patients in relation to the time when the last BMD had been measured. Significant fluctuations (p < 0.001) in RD were observed in relation to time. These RD variations suggested the existence of a time-related error. The presence of this error is also substantiated by the fact that a parallelism existed between the curve of the RD variations and the curve of the mean values of BMD of all patients referred to our department, calculated per period of 4 months. Although the fluctuation of the latter curve was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)     

Freezing of gait affects quality of life of peoples with Parkinson's disease beyond its relationships with mobility and gait.

The aim of this study was to examine the association between freezing of gait (FOG) and quality of life (QoL) in patients with Parkinson's disease (PD). PD patients (n = 118) completed the PDQ-39 (QoL) and FOG-Q questionnaires. Disease severity was assessed by the Hoehn and Yahr (H&Y) staging and the Unified Parkinson's Disease Rating Scale (UPDRS). The relations between those parameters were assessed using regression models. 66 men and 52 women (mean age 65.8 +/- 10.2 years, UPDRS total score 48.4 +/- 17.1, disease duration 8.5 +/- 5.8 years, H&Y stage 2.7 +/- 0.8) participated. FOG severity had a significant effect on QoL (P < 0.0015), accounting for disease severity assessed by UPDRS. Specifically, FOG severity was correlated with all the dimensions of the PDQ-39 except for stigma and social support, as follows: with mobility, bodily discomfort, activity of daily living (ADL) (P < 0.005 in all), with emotional, communication, and cognition (P < 0.05 in all). FOG severity (FOG-Q) was also found to affect a modified PDQ total score, without the mobility aspect (P = 0.0081). FOG should be viewed as a highly important symptom with regard to QoL of PD patients beyond its effect on gait and mobility. On the basis of the present results, special attention should be given to FOG in the treatment of patients with PD.     

Ambulatory blood pressure monitoring: practical considerations

Ambulatory blood pressure monitoring (ABPM) allows one to evaluate the blood pressure (BP) profile over a 24-hour period in the patient's natural environment. Casual pressure measurements in the physician's office can be affected by alarm reactions, thus causing "white coat" hypertension. ABPM allows one to evaluate these reactions and determine the average pressure and variability of BP along with the effects of physical activity and emotional arousal on BP patterns while at work, at home, and during sleep. Average pressures determined by ABPM are more predictive of target organ involvement and cardiovascular complications of hypertension than casual monitoring of BP in the clinic. The absence of physiologic decline in arterial pressure during sleep is associated with increased prevalence of atherosclerotic complications and left ventricular hypertrophy as well as impairment of the autonomic nervous system. Although further prospective studies are needed to confirm the benefits of home pressure readings and ABPM, ABPM can be helpful in the diagnosis and determination of prognosis and therapeutic responses in a select group of patients.     

Hypernychthemeral sleep-wake cycle: some hidden regularities

A patient with a sleep-wake cycle greater than 24 h recorded his sleep-onset and wake times for 4 years. During this time the patient found himself unable to maintain a 24-h sleep-wake schedule. The lengths of his sleep-wake periods (subjective days) and his sleep periods were highly variable. Nonetheless, there were certain unexpected regularities in his sleep-wake data, corresponding to fixed clock hours. Across the 4-year period, there were certain clock hours during which sleep onset and waking were likely to occur and certain clock hours that may be considered forbidden zones for sleep, during which the patient rarely either began or ended a sleep period. It is possible that the unexpected regularities resulted from partial entrainment to external cues or from some residual influence of an endogenous ultradian-regulating mechanism.