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PubMed2000

Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoing angioplasty for acute myocardial infarction.

CONTEXT: Rapid time to treatment with thrombolytic therapy is associated with lower mortality in patients with acute myocardial infarction (MI). However, data on time to primary angioplasty and its relationship to mortality are inconclusive. OBJECTIVE: To test the hypothesis that more rapid time to reperfusion results in lower mortality in the strategy of primary angioplasty. DESIGN: Prospective observational study of data collected from the Second National Registry of Myocardial Infarction between June 1994 and March 1998. SETTING: A total of 661 community and tertiary care hospitals in the United States. SUBJECTS: A cohort of 27,080 consecutive patients with acute MI associated with ST-segment elevation or left bundle-branch block who were treated with primary angioplasty. MAIN OUTCOME MEASURE: In-hospital mortality, compared by time from acute MI symptom onset to first balloon inflation and by time from hospital arrival to first balloon inflation (door-to-balloon time). RESULTS: Using a multivariate logistic regression model, the adjusted odds of in-hospital mortality did not increase significantly with increasing delay from MI symptom onset to first balloon inflation. However, for door-to-balloon time (median time 1 hour 56 minutes), the adjusted odds of mortality were significantly increased by 41% to 62% for patients with door-to-balloon times longer than 2 hours (for 121-150 minutes: odds ratio [OR], 1.41; 95% confidence interval [CI], 1.08-1.84; P=.01; for 151-180 minutes: OR, 1.62; 95% CI, 1.23-2.14; P<.001; and for >180 minutes: OR, 1.61; 95% CI, 1.25-2.08; P<.001). CONCLUSIONS: The relationship in our study between increased mortality and delay in door-to-balloon time longer than 2 hours (present in nearly 50% of this cohort) suggests that physicians and health care systems should work to minimize door-to-balloon times and that door-to-balloon time should be considered when choosing a reperfusion strategy. Door-to-balloon time also appears to be a valid quality-of-care indicator. JAMA. 2000.

Aged↗
PubMed1996

An exploratory study into the experience of part-time nurse teachers compared to full-time nurse teachers.

The part-time labour force, in nursing as elsewhere, is often unacknowledged, or conveniently assumed to have lesser commitment than the full-time labour force (Davies 1990). This paper reports the findings of an ethnographic study of five part-time nurse teachers and five full-time nurse teachers, which explored whether organisational and other constraints experienced by five part-time nurse teachers at one college of nursing, were the same for full-time nurse teachers. Four major themes emerged from the findings. Three constraints were identified by both part-time and full-time members, and they were related to issues of communication networks, valuing colleagues, and the results of coercive psychological contracts. The full-time teachers experienced these constraints but apparently to a lesser degree. The fourth theme was related to part-time teachers only. They identified that the flexibility of part-time hours enabled them to make compromises between their professional and other roles. The results of this study suggest that there is a need for part-time and full-time nurse teachers to work together in a collaborative manner, so that they are able to negotiate local working arrangements.

Cooperative Behavior↗
PubMed2004

Full-time occlusion compared to part-time occlusion for the treatment of amblyopia.

BACKGROUND: Occlusion of the better-seeing eye as a method of treatment for amblyopia has long been a standard of care. A difference exists between practitioners on using either full-time occlusion or part-time occlusion. METHODS: A retrospective review of pediatric patients (ages 3 to 7 years) with amblyopia was performed. The patients were prescribed either full-time occlusion or part-time occlusion for the primary treatment of their amblyopia. Exclusions were made for patients with an organic or structural component of their amblyopia. Twenty-one patients were included in the full-time occlusion group and 24 patients were included in the part-time occlusion group. RESULTS: Seventy-six percent of patients who completed full-time occlusion achieved 20/40 acuity or better and 67% achieved 20/30 or better, with an average treatment time of six weeks. Fifty-eight percent of patients who completed part-time occlusion achieved 20/40 acuity or better and only 46% achieved 20/30 or better, with an average treatment time of 26 weeks. For patients with 20/80 or worse amblyopia, 82% achieved 20/40 or better with full-time occlusion. Only 40% of part-time occluders with 20/80 or worse achieved 20/40. Occlusion amblyopia did not develop in any patient. CONCLUSION: A higher percentage of amblyopic patients treated with full-time occlusion achieved 20/30 acuity in the amblyopic eye over a shorter duration of treatment.

Amblyopia↗
PubMed2004

Time experience and time judgment in major depression, mania and healthy subjects. A controlled study of 93 subjects.

OBJECTIVE: Studies on the time sense of depressed patients have revealed inconsistent results. Manic patients have been almost neglected. METHOD: Patients with a major depressive episode (n = 32), or a manic episode (n = 30) (both Diagnostic and Statistical Manual of Mental Disorders-IV, Mini-International Neuropsychiatric Interview-confirmed), and 31 healthy controls were included. The subjective time experience was assessed by a visual analog scale (VAS), the objectively measurable time judgment abilities by the Chronotest, a computer program developed for this study, consisting of time estimation and time production tasks. RESULTS: Controls reported a balanced, manic patients an enhanced, and depressive patients a slowed experience of time flow in the VAS (P < 0.001). In the time judgment tasks, however, both depressed and manic patients showed time overestimation for the longer time spans (P < 0.008). CONCLUSION: This largest study on time sense in manic patients confirmed results of a divergent alteration of time experience in depressive and in manic patients but revealed an uniform time overestimation by both patient groups in time judgment tasks.

Analysis of Variance↗
PubMed1997

A comparison of the effects of aspirin on bleeding time measured using the Simplate method and closure time measured using the PFA-100, in healthy volunteers.

AIMS: The aim of this study was to compare the effects of aspirin on platelet function as measured by the 'classical' template bleeding time with a new ex vivo method measuring closure times using the PFA-100 machine. Platelet aggregation in response to arachidonic acid was also measured ex vivo. METHODS: The trial was a randomized, double-blind, placebo-controlled crossover design, with each volunteer taking 750 mg aspirin (BP) or placebo, three times a day for 5 days, with an 18 day wash-out period between treatments. Bleeding times and closure times were measured before the first dose on the first day and 0.5 h after the last dose on the fifth day of each treatment period. They were also measured 2 weeks after the last day of the trial. RESULTS: Baseline bleeding times (pre-placebo) were 415 s using the Simplate, whilst baseline closure times were 115 s using the PFA-100. Aspirin treatment caused an increase of both the template bleeding time (61%) and the closure time of the PFA-100 (79%) when compared with the effects of placebo. The platelet aggregatory response to arachidonic acid was completely inhibited following aspirin treatment and was unaffected following placebo. Two weeks after the end of the trial, all values had returned to pre-treatment levels. The template bleeding time was unaltered in 1 of the 12 volunteers during aspirin treatment and was significantly prolonged in 3 of the 12 volunteers during placebo treatment. The PFA-100 closure time was unaltered in 1 of the 12 volunteers during aspirin treatment and was prolonged in 1 subject during placebo treatment. CONCLUSIONS: The change in closure time using the PFA-100 is as sensitive and reproducible to the effects of aspirin on platelet function as is the template bleeding time test. However, the PFA-100 produced less variable effects with fewer false positive results.

Adult↗
PubMed1996

Time constants in thermal laser medicine: II. Distributions of time constants and thermal relaxation of tissue.

The thermal response of a semi-infinite medium in air, irradiated by laser light in a cylindrical geometry, cannot accurately be approximately by single radial and axial time constants for heat conduction. This report presents an analytical analysis of hear conduction where the thermal response is expressed in terms of distributions over radial and axial time constants. The source term for heat production is written as the product of a Gaussian shaped radial term and an exponentially shaped axial term. The two terms are expanded in integrals over eigenfunctions of the radial and axial parts of the Laplace heat conduction operator. The result is a double integral over the coupled distributions of the two time constants to compute the temperature rise as a function of time and of axial and radial positions. The distribution of axial time constants is a homogeneous slowly decreasing function of spatial frequency (v) indicating that one single axial time constant cannot reasonably characterize axial heat conduction. The distribution of radial time constants is a function centred around a distinguished maximum in the spatial frequency (lambda) close to the single radial time constant value used previously. This suggests that one radial time constant to characterize radial heat conduction may be a useful concept. Special cases have been evaluated analytically, such as short and long irradiation times, axial or radial heat conduction (shallow or deep penetrating laser beams) and, especially, thermal relaxation (cooling) of the tissue. For shallow penetrating laser beams the asymptotic cooling rate is confirmed to be proportional to [(t)0.5-(t-tL)0.5] which approaches 1/t0.5 for t >> tL, where t is the time and tL is the laser pulse duration. For deep penetrating beams this is proportional to 1/(t-tL). For intermediate penetration, i.e. penetration depths about equal to spot size diameters, this is proportional to 1/(t-tL)1.5. The double integral has been evaluated numerically and the results have been compared with the various approximations available including the new results and the single time constant model. The present analysis completes our previous work, presents a closed-form formulation for the non-ablative thermal response of laser irradiated tissue and provides insight into the practical value of using time constants for representing heat conduction effects, in particular for the rate of cooling of the tissue surface.

Air↗
PubMed2004

A real-time architecture for time-aware agents.

This paper describes the specification and implementation of a new three-layer time-aware agent architecture. This architecture is designed for applications and environments where societies of humans and agents play equally active roles, but interact and operate in completely different time frames. The architecture consists of three layers: the April real-time run-time (ART) layer, the time aware layer (TAL), and the application agents layer (AAL). The ART layer forms the underlying real-time agent platform. An original online, real-time, dynamic priority-based scheduling algorithm is described for scheduling the computation time of agent processes, and it is shown that the algorithm's O(n) complexity and scalable performance are sufficient for application in real-time domains. The TAL layer forms an abstraction layer through which human and agent interactions are temporally unified, that is, handled in a common way irrespective of their temporal representation and scale. A novel O(n2) interaction scheduling algorithm is described for predicting and guaranteeing interactions' initiation and completion times. The time-aware predicting component of a workflow management system is also presented as an instance of the AAL layer. The described time-aware architecture addresses two key challenges in enabling agents to be effectively configured and applied in environments where humans and agents play equally active roles. It provides flexibility and adaptability in its real-time mechanisms while placing them under direct agent control, and it temporally unifies human and agent interactions.

Algorithms↗
PubMed2005

Supra-maximal effort and reaction and movement times in a non-compatible response time task.

AIM: The primary purpose of this study was to examine the effect of attempting to exercise supra-maximally on reaction time and movement time in a non-compatible response time task. METHODS: Subjects (n=9) undertook a 4-choice non-compatible response time test at rest, while cycling at 70 rpm with a resistance of 35 W (low intensity exercise), cycling at 70% of their maximum power output (MPO), cycling at 100% MPO and attempting to cycle at 70 rpm, with a resistance that was 28 W greater than the resistance required to elicit MPO (supra-maximal effort). RESULTS: Reaction time, movement time, intra-individual variations in reaction time and movement time at each exercise intensity were compared by a series of repeated measures analyses of variance. A significant effect of exercise was shown for movement time, F(4,32)=6.05, p<0.001, eta2=0.44, Power=0.97 and intra-individual variation in reaction time, F(4,32)=4.98, p<0.005, eta2=0.38, Power=0.93. For movement time, Tukey post-hoc tests showed that performance at rest was significantly slower than that during exercise at 70%, 100% MPO and supra-maximal effort. Performance at low intensity exercise was significantly slower than that at MPO. For intra-individual variations in reaction time, Tukey tests found that variations under supra-maximal effort and MPO were significantly greater than those at low intensity and 70% MPO. CONCLUSIONS: It was concluded that exercise facilitates speed of movement when the limbs used for the motor task are not the ones that are being exercised. Reaction time during maximal and supra-maximal exercise demonstrates large intra-individual variations.

Adult↗
PubMed1993

New bleeding time devices with retractable blades evaluated in children, healthy volunteers and patients with prolonged bleeding time.

The Simplate II-R and the Simplate Paediatric, are two new Simplate bleeding time devices with retractable blades. In this study we compared the Simplate II-R with the Simplate II bleeding time and found a good correlation when performed by the same technician both in 30 healthy volunteers and in 7 patients with prolonged bleeding time. The same normal ranges may be applied for the Simplate II-R as for the Simplate II bleeding time. The Simplate II-R bleeding time was highly reproducible in healthy volunteers when performed by the same technician. We found no correlation between age and bleeding time, and no significant difference in bleeding time between males and females. We performed the Simplate Paediatric bleeding time test and calculated the normal ranges in 84 healthy children in 4 age groups: 3 days, 3 months, 1 year and 3-6 years of age. The Simplate Paediatric bleeding times were shorter in the children than the Simplate II-R bleeding times in the adults. We found no significant correlation between bleeding time and the inverse platelet count, and no significant difference in bleeding time between boys and girls. The retractable blades in the Simplate II-R and the Simplate Paediatric reduce the risk of accidental cuts. Both devices yield reproducible bleeding time measurements and can be used instead of older Simplate variants.

Adult↗
PubMed2006

Differentiation of hepatocellular carcinoma and hepatic metastasis from cysts and hemangiomas with calculated T2 relaxation times and the T1/T2 relaxation times ratio.

PURPOSE: To determine the diagnostic capability of the T1 and T2 relaxation times and the T1/T2 relaxation times ratio generated with the mixed turbo spin echo (mixed-TSE) pulse sequence, in order to discriminate between hepatocellular carcinoma (HCC)/metastases and hemangiomas/cysts. MATERIALS AND METHODS: A retrospective review of 36 MR examinations implementing the mixed-TSE pulse sequence demonstrated 70 focal hepatic lesions. Quantitative MR algorithms were used to generate T1 and T2 relaxation times, and the T1/T2 relaxation times ratio for each lesion. A two-sample t-test compared mean T1 and T2 relaxation times, and the T1/T2 relaxation times ratio, by lesion type: carcinoma/metastases and hemangiomas/cysts. Sensitivity and specificity for discriminating carcinoma/metastases from hemangiomas/cysts with T2 relaxation time thresholds of 112 and 125 msec, as well as a ratio of T1/T2 relaxation times of 5.8, were calculated. RESULTS: Using a T2 relaxation time threshold of 112 msec, 92% sensitivity and 100% specificity discriminating cysts/hemangiomas from HCC/liver metastasis was demonstrated. With a threshold of 125 msec, 96% sensitivity and 98% specificity was demonstrated. There was no correlation between calculated T1 relaxation times and type of lesion. Using a T1/T2 relaxation times ratio of 5.8, 100% sensitivity and specificity were demonstrated. CONCLUSION: Although there is high sensitivity and specificity associated with the use of T2 relaxation times alone to discriminate carcinoma/metastases from hemangiomas/cysts, using the T1/T2 relaxation times ratio threshold of 5.8 allowed proper classification of all lesions.

Algorithms↗
PubMed1985

Strategies and tactics in NMR imaging relaxation time measurements. I. Minimizing relaxation time errors due to image noise--the ideal case.

The effect of NMR image noise on errors in calculated values of relaxation times is quantitatively assessed by use of relaxation time noise figures, which are derived on the basis of statistical principles as functions of pulse delay, repetition, and recovery intervals for several types of pulse sequences. Two strategies for determining relaxation times are considered: two point (ratio of intensities for two experiments) and multipoint (least-squares fit of intensities to pulse-sequence functions for n experiments). For given total measurement times, values of pulse interval times are found which give minimum relaxation time noise figures. A comparison of ratio methods shows that the best is a combination saturation-recovery, inversion-recovery (SR/IR) technique. For short measurement times (less than about 10T1) this optimized SR/IR ratio determination is also superior to the best multipoint method, a series of inversion-recovery experiments with equally incremented inversion-recovery times. An examination of the effect of signal averaging on the relaxation time noise shows that up to a measurement time characteristic of the particular method used (e.g., for times up to about 5T1 for the SR/IR ratio determination, 100T1 for the multipoint inversion-recovery method), increased measurement time is more effectively allotted to longer pulse intervals than to signal averaging. Numerical examples are tabulated which can help one to set optimum values for pulse intervals, given a rough estimate of the relaxation time to be determined.

Magnetic Resonance Spectroscopy↗
PubMed1997

Subpopulations of human granulosa-luteal cells obtained during early timed and during normally timed follicular aspiration in in-vitro fertilization-embryo transfer cycles.

OBJECTIVE: To find the differences between human granulosa-luteal cells obtained during early timed follicular aspiration to prevent severe ovarian hyperstimulation syndrome (OHSS) and during normally timed follicular aspiration. DESIGN: Retrospective analysis of clinical laboratory data. SETTING: In vitro fertilization unit, University Department of Obstetrics and Gynecology, Ljubljana, Slovenia. PATIENT(S): Twenty women undergoing IVF-ET at high risk for OHSS. INTERVENTION(S): Cells were obtained from the follicles of women who were stimulated with hMG and hCG during an early timed follicular aspiration of one ovary, 10-12 hours after hCG, and during a normally timed follicular aspiration of the contralateral ovary, 32-36 hours after hCG administration. MAIN OUTCOME MEASURE(S): Subpopulations of granulosa-luteal cells were observed by computerized image analysis in which hCG was localized using immunoperoxidase staining. RESULT(S): Early timed follicular aspirates contained no oocytes and only a scant number of granulosa cells. Granulosa-luteal cells were smaller than those from normally timed follicular aspirates. We identified three subpopulations in early timed follicular aspirates: nonluteinized, small luteinized, and medium luteinized cells. In normally timed follicular aspirates, four subpopulations were identified, including large luteinized cells. The normally timed follicular aspirates contained more hCG-stained cells. Three staining types of hCG localization were found: on the surface membrane, on the surface membrane and within the cytoplasm, and only within the cytoplasm of cells from normally timed follicular aspirates. Early timed follicular aspirates contained only cells with membrane hCG localization. CONCLUSION(S): We found differences in morphometric characteristics and hCG localization between human granulosa-luteal cells obtained during early timed follicular aspiration to prevent severe OHSS and during normally timed follicular aspiration.

Adult↗
PubMed2004

Television viewing, computer game playing, and Internet use and self-reported time to bed and time out of bed in secondary-school children.

OBJECTIVE: To investigate the relationship between the presence of a television set, a gaming computer, and/or an Internet connection in the room of adolescents and television viewing, computer game playing, and Internet use on the one hand, and time to bed, time up, time spent in bed, and overall tiredness in first- and fourth-year secondary-school children on the other hand. METHODS: A random sample of students from 15 schools in Flanders, Belgium, yielded 2546 children who completed a questionnaire with questions about media presence in bedrooms; volume of television viewing, computer game playing, and Internet use; time to bed and time up on average weekdays and average weekend days; and questions regarding the level of tiredness in the morning, at school, after a day at school, and after the weekend. RESULTS: Children with a television set in their rooms went to bed significantly later on weekdays and weekend days and got up significantly later on weekend days. Overall, they spent less time in bed on weekdays. Children with a gaming computer in their rooms went to bed significantly later on weekdays. On weekdays, they spent significantly less time in bed. Children who watched more television went to bed later on weekdays and weekend days and got up later on weekend days. They spent less time in bed on weekdays. They reported higher overall levels of being tired. Children who spent more time playing computer games went to bed later on weekdays and weekend days and got up later on weekend days. On weekdays, they actually got up significantly earlier. They spent less time in bed on weekdays and reported higher levels of tiredness. Children who spent more time using the Internet went to bed significantly later during the week and during the weekend. They got up later on weekend days. They spent less time in bed during the week and reported higher levels of tiredness. Going out was also significantly related to sleeping later and less. CONCLUSION: Concerns about media use should not be limited to television. Computer game playing and Internet use are related to sleep behavior as well. Leisure activities that are unstructured seem to be negatively related to good sleep patterns. Imposing more structure (eg, end times) might reduce impact.

Child↗
PubMed2002

The effect of timing of administration of oestradiol benzoate on characteristics of oestrus, timing of ovulation and fertility in Bos indicus heifers synchronised with a progesterone releasing intravaginal insert.

OBJECTIVE: To compare the timing of onset of oestrus and ovulation, characteristics of oestrus, and fertility in Bos indicus heifers synchronised with a progesterone releasing intravaginal insert (IVP4) and administration of oestradiol benzoate (ODB) either at the time of removal of the insert or 24 h later. DESIGN: Cohort study. PROCEDURE: Bos indicus and Bos indicus cross heifers were treated on two farms (Farm A, n = 273; Farm B, n = 47) with an IVP4 for 8 days with 1.0 mg of ODB administered at the time of device insertion and 250 mg of cloprostenol at the time of device removal. Heifers in the ODB-0 group were administered 0.75 mg of ODB at the time of device removal while heifers in the ODB-24 group were administered the same dose of ODB 24 h after device removal. Heifers were inseminated once daily after detection of oestrus. Heifers not detected in oestrus by 72 h after removal of inserts were inseminated at that time. Oestrus was detected in heifers on Farm A using heatmount detectors while on Farm B oestrus in heifers was monitored using radiotelemetry of mounting pressure. Ovarian follicular development was monitored daily in 30 heifers on Farm B from the time of administration of inserts until ovulation to a maximum of 96 h after removal of inserts, and again 11 days after removal of inserts (Day 19). A blood sample was collected from all heifers on Farm B on Day 19 and analysed for plasma concentration of progesterone. Pregnancy was diagnosed 6 to 8 weeks after insemination. RESULTS: Administration of ODB at the time of removal of inserts shortened the time interval to oestrus and ovulation (P < 0.001), increased the number of mounts recorded during oestrus (P = 0.04) and reduced the odds of pregnancy (P = 0.03). The proportion of heifers ovulating on Farm B was 67% and was not affected by treatment group (P = 0.61). The mean diameter of the largest follicle measured in ovaries was greater at the time of removal of inserts (9.1 +/- 0.6 vs 10.7 +/- 0.4; P = 0.03) and at the expected time of the LH surge (8.1 +/- 0.4 vs 11.5 +/- 0.3 mm; P < 0.001) in heifers that ovulated compared to heifers that failed to ovulate, respectively. Emergence of a new follicular wave was not detected during the synchronisation treatment in heifers that failed to ovulate. Concentrations of progesterone in plasma on Day 19 were less in non-pregnant heifers (P = 0.05) compared to heifers subsequently diagnosed as pregnant to insemination and were affected by the diameter of the ovulatory follicle (P = 0.01). CONCLUSION: Administration of ODB at the time of removal of inserts can shorten the time interval to oestrus and ovulation and can reduce fertility when insemination is carried out once daily. Further work is needed to determine if prolonged suppression of follicular development, anovulatory oestrus and premature ovulation occuring in some heifers is associated with administration of ODB.

Administration, Intravaginal↗
PubMed2005

Effect of gait speed on gait rhythmicity in Parkinson's disease: variability of stride time and swing time respond differently.

BACKGROUND: The ability to maintain a steady gait rhythm is impaired in patients with Parkinson's disease (PD). This aspect of locomotor dyscontrol, which likely reflects impaired automaticity in PD, can be quantified by measuring the stride-to-stride variability of gait timing. Previous work has shown an increase in both the variability of the stride time and swing time in PD, but the origins of these changes are not fully understood. Patients with PD also generally walk with a reduced gait speed, a potential confounder of the observed changes in variability. The purpose of the present study was to examine the relationship between walking speed and gait variability. METHODS: Stride time variability and swing time variability were measured in 36 patients with PD (Hoehn and Yahr stage 2-2.5) and 30 healthy controls who walked on a treadmill at four different speeds: 1) Comfortable walking speed (CWS), 2) 80% of CWS 3) 90% of CWS, and 4) 110% of CWS. In addition, we studied the effects of walking slowly on level ground, both with and without a walker. RESULTS: Consistent with previous findings, increased variability of stride time and swing time was observed in the patients with PD in CWS, compared to controls. In both groups, there was a small but significant association between treadmill gait speed and stride time variability such that higher speeds were associated with lower (better) values of stride time variability (p = 0.0002). In contrast, swing time variability did not change in response to changes in gait speed. Similar results were observed with walking on level ground. CONCLUSION: The present results demonstrate that swing time variability is independent of gait speed, at least over the range studied, and therefore, that it may be used as a speed-independent marker of rhythmicity and gait steadiness. Since walking speed did not affect stride time variability and swing time variability in the same way, it appears that these two aspects of gait rhythmicity are not entirely controlled by the same mechanisms. The present findings also suggest that the increased gait variability in PD is disease-related, and not simply a consequence of bradykinesia.

Journal Article↗
PubMed2003

Inclusion of turnover time does not influence identification of surgical services that over- and underutilize allocated block time.

UNLABELLED: Allocation of operating room (OR) block time is an ongoing challenge for OR managers. In this study, we sought to determine whether inclusion or exclusion of turnover time in comparisons of block utilization would identify different surgical services as under- or overused. For a 13-mo period, we evaluated data extracted from the OR information system of a large academic medical center. During that time period, 15 surgical services performed 12,245 surgical procedures. Allocated block hours, number of first cases performed, total number of cases, and average case durations were determined. The average turnover time for each service was determined by a manual, case-by-case review of data from 1 mo. Raw utilization (RU; case durations only) and adjusted utilization (AU; case duration plus turnover time) were calculated for each service. Turnover time was credited to the service performing surgery after room turnover. Case du-ration was limited to surgeries performed during resource hours. Two indices of utilization (i.e., the usage rate of the service divided by the overall use of all ORs in the suite) were used to compare services: the RU or AU Index (RUI or AUI). Outliers were services with indices that were >1.15 or <0.85. The RUI identified three services as underutilizers and one service as an overutilizer. Using the AUI, the same outliers were identified, and no new services were identified. Examining the changes in index (between AUI and RUI), the percentage of to-follow cases highly correlated with changes in index (r(2) = 0.60); the average turnover time did not (r(2) = 0.002). Inclusion of turnover time did not change the services that were identified as under- and overutilizer. IMPLICATIONS: Turnover time is difficult to determine from existing operating room information systems. This study determined the use of block time with and without turnover time for each surgical service in a large academic hospital. Turnover time did not change identification of surgical services that over- (one service) or underused (three services) allocated block time.

Operating Rooms↗
PubMed1987

Analysis of myocardial time-activity curves of 123I-heptadecanoic acid. II. The acquisition time.

Optimal fitting of a myocardial time-activity curve is accomplished with a monoexponential plus a constant, resulting in three parameters: amplitude and half-time of the monoexponential and the constant. The aim of this study was to estimate the precision of the calculated parameters. The variability of the parameter values as a function of the acquisition time was studied in 11 patients with cardiac complaints. Of the three parameters the half-time value varied most strongly with the acquisition time. An acquisition time of 80 min was needed to keep the standard deviation of the half-time value within +/- 10%. To estimate the standard deviation of the half-time value as a function of the parameter values, of the noise content of the time-activity curve and of the acquisition time, a model experiment was used. In most cases the SD decreased by 50% if the acquisition time was increased from 60 to 90 min. A low amplitude/constant ratio and a high half-time value result in a high SD of the half-time value. Tables are presented to estimate the SD in a particular case.

Coronary Disease↗
PubMed2001

Timing and volume of fluid administration for patients with bleeding following trauma.

BACKGROUND: Treatment of haemorrhagic shock involves maintaining blood pressure and tissue perfusion until bleeding is controlled. Different resuscitation strategies have been used to maintain the blood pressure in trauma patients until bleeding is controlled. However, while maintaining blood pressure may prevent shock, it may worsen bleeding. OBJECTIVES: To assess the effects of early versus delayed, and larger versus smaller volume of fluid administration in trauma patients with bleeding. SEARCH STRATEGY: We searched the Cochrane Controlled Trials Register, the specialised register of the Injuries Group, MEDLINE, EMBASE, the National Research Register and the Science Citation Index. We checked reference lists of identified articles and contacted authors and experts in the field. SELECTION CRITERIA: Randomised trials of the timing and volume of intravenous fluid administration in trauma patients with bleeding. Trials in which different types of intravenous fluid were compared were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: We did not combine the results quantitatively because the interventions and patient populations were so diverse. Early versus delayed fluid administration: Three trials reported mortality and two coagulation data. In the first trial (n=598) relative risk (RR) for death with early fluid administration was 1.26 (95% confidence interval of 1.00-1.58). The weighted mean differences (WMD) for prothrombin time and partial thromboplastin time were 2.7 (95% CI 0.9-4.5) and 4.3 (95% CI 1.74-6.9) seconds respectively. In the second trial (n=50) RR for death with early blood transfusion was 5.4 (95% CI 0.3-107.1). The WMD for partial thromboplastin time was 7.0 (95% CI 6.0-8.0) seconds. In the third trial (n=1309) RR for death with early fluid administration was 1.06 (95% CI 0.77-1.47). Larger versus smaller volume of fluid administration: Three trials reported mortality and one coagulation data. In the first trial (n=36) RR for death with a larger volume of fluid resuscitation was 0.80 (95% CI 0.28-22.29). Prothrombin time and Partial thromboplastin time were 14.8 and 47.3 seconds in those who received a larger volume of fluid as compared to 13.9 and 35.1 seconds in the comparison group. In the second trial (n=99) RR for death with a high (100 mm Hg) compared to low (70 mm Hg) systolic blood pressure resuscitation target was 1.02 (95% CI 0.27-3.85). In the third trial (n=25) there were no deaths. REVIEWER'S CONCLUSIONS: We found no evidence from randomised controlled trials to support early or larger volume of intravenous fluid administration in uncontrolled haemorrhage. There is continuing uncertainty about the best fluid administration strategy in bleeding trauma patients. Further randomised controlled trials are needed to establish the most effective fluid resuscitation strategy.

Hemorrhage↗