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W Guerra

Publications and source records attributed to W Guerra.

7 recordsLinked to original sources
PubMed2001

Comparison of quality and cost-effectiveness in the evaluation of symptomatic cholelithiasis with different approaches to ultrasound availability in the ED.

Ultrasound is the imaging study of choice for the detection of gallstones, but ultrasound through medical imaging departments (MI Sono) is not readily available on an immediate basis in many emergency departments (EDs). Several studies have shown that emergency physicians can perform ultrasound themselves (ED Sono) to rule out gallstones with acceptable accuracy after relatively brief training periods, but there have been no studies to date specifically addressing the effect of ED Sono of the gallbladder on quality and cost-effectiveness in the ED. In this study, we investigated measures of quality and cost-effectiveness in evaluating patients with suspected symptomatic cholelithiasis during three different years with distinctly different approaches to ultrasound availability. The study retrospectively identified a total of 418 patients who were admitted for cholecystectomy or for a complication of cholelithiasis within 6 months of an ED visit for possible biliary colic. The percentage of patients who had gallstones documented at the first ED visit improved from 28% in 1993, when there was limited availability of ultrasound through the Medical Imaging Department (MI Sono), to 56% in 1995, when MI Sono was readily available, to 70% in 1997, when both MI Sono and ED Sono were readily available (P <.001). There were also significant differences over the 3 years in the mean number of days from the first ED visit to documentation of gallstones (19.7 in 1993, 10.7 in 1995, 7.4 in 1997, P <.001); the mean number of return visits for possible biliary colic before documentation of gallstones (1.67 in 1993, 1.24 in 1995, and 1.25 in 1997, P <.001); and the incidence of complications of cholelithiasis in the interval between the first ED visit for possible biliary colic and the date of documentation of cholelithiasis (6.8% in 1993, 5.9% in 1995, 1.5% in 1997, P =.049). The number of MI Sonos ordered by emergency physicians per case of symptomatic cholelithiasis identified increased from 1.7 in 1993 to 2.5 in 1995 and dropped back to 1.7 in 1997, when 4.2 ED Sonos per study case were also done. The cost of ED Sonos was more than offset by savings in avoiding calling in ultrasound technicians after regular Medical Imaging Department hours. The indeterminate rate for ED Sonos was 18%. Excluding indeterminates, the sensitivity of ED Sono for detection of gallstones was 88.6% (95% CI 83.1-92.8%), the specificity 98.2% (95% CI 96.0-99.3%), and the accuracy 94.8% (95% CI 92.5-96.5%). We conclude that greater availability of MI Sono in the ED was associated with improved quality in the evaluation of patients with suspected symptomatic cholelithiasis but also with increased ultrasound costs. The availability of ED Sono in addition to readily available MI Sono was associated with further improved quality and decreased costs. The indeterminate rate for ED Sono was relatively high, but excluding indeterminates, the accuracy of ED Sono was comparable with published reports of MI Sono.

Adolescent↗
PubMed2000

Ultrasound availability in the evaluation of ectopic pregnancy in the ED: comparison of quality and cost-effectiveness with different approaches.

The liberal use of ultrasonography has been advocated in patients with first trimester cramping or bleeding to avoid misdiagnosis of ectopic pregnancy in the emergency department (ED). The cost-effectiveness of different approaches to ultrasound availability has not been previously reported. In this study, we investigated measures of quality and cost-effectiveness in detecting ectopic pregnancy in the ED over a 6-year period, divided into three approximately equal epochs with three distinct approaches to ultrasound availability. The study retrospectively identified 120 cases of ectopic pregnancy seen in the ED over 6 years. There was significant improvement in the percentage of patients with ectopic pregnancy who were documented to have absence of intrauterine pregnancy (IUP) at the first visit from 76% during Epoch 1, when there was limited availability of ultrasound through medical imaging (MI Sono), to 88% in Epoch 2, when MI Sono was readily available, to 96% in Epoch 3, when both MI Sono and ultrasound by emergency physicians (ED Sono) were readily available (P = .02). The estimated number of MI Sonos ordered by emergency physicians in patients at risk for ectopic pregnancy increased from 5.2 per ectopic pregnancy in Epoch 1 to 11.8 per ectopic pregnancy in Epoch 2, and declined to 5.5 per ectopic pregnancy in Epoch 3, when 19.9 ED Sonos per ectopic pregnancy were also done. The cost of ED Sono in Epoch 3 was more than offset by savings from avoiding calling in ultrasound technicians after regular medical imaging department hours. The specificity of ED Sono in ruling in an IUP was 100% (95% CI 98.3 to 100%), but analysis of secondary quality indicators reflecting times from first ED visit to treatment in Epoch 3 raised the possibility that an adnexal mass or signs of tubal rupture may have been missed on some ED Sonos. We conclude that increased availability of ultrasonography leads to improved quality in the detection of ectopic pregnancy in the ED, but at the expense of a disproportionate increase in the number of ultrasound studies done per ectopic pregnancy detected. Our study suggests that the most cost-effective strategy is for emergency physicians to screen all patients with first trimester cramping and bleeding with ED Sonos, and to obtain MI Sonos at the time of the initial ED visit in all cases in which the ED Sono is indeterminate or shows no IUP.

Adult↗
PubMed1999

Patient satisfaction and diagnostic accuracy with ultrasound by emergency physicians.

In recent years, there has been considerable interest and controversy concerning the performance of ultrasound by emergency physicians (ED Sono), but patient satisfaction with ED Sono has not been well studied. The primary purpose of this investigation was to assess the level of patient satisfaction with ED Sono and to compare satisfaction with ED Sono with ultrasound by the Medical Imaging Department (MI Sono). A secondary objective was to assess the accuracy of ED Sono at our facility. During a 5-month period, which included the startup phase of a program for ED Sono, emergency physicians prospectively identified patients who were candidates for ultrasound as a part of their workup. Patients were contacted by telephone after their ED visit and asked to rate satisfaction on a 0 to 10 scale for various aspects of their care, including the ultrasound if one was done. The accuracy of ED Sono was determined by comparing ED ultrasound interpretations with surgical pathology, repeat imaging studies, or clinical follow-up. Two hundred forty patients were entered into the study, and 186 (78%) responded to the satisfaction survey. Satisfaction ratings were similarly high for ED Sono (mean, 8.9; 95% Cl, 8.6 to 9.2) and for MI Sono (mean, 8.8; 95% Cl, 8.2 to 9.4). Eighteen percent of ultrasounds performed by emergency physicians were indeterminate. Excluding indeterminate scans and scans for which confirmation was not possible, the accuracy of ED Sono was 99.1% (95% Cl, 95.1% to >99.9%). We conclude that during the startup phase of our ED Sono program, patient satisfaction was high, and the error rate was very low.

Adult↗
PubMed1990

Ionic modulation of triethyllead neurotoxicity in cerebellar granule cell culture.

While the molecular mechanism underlying triethyllead (TEL) neurotoxicity is unknown, we hypothesize that triethyllead mediates an accelerated Cl-/OH exchange across neuronal membranes leading to prolonged depolarization and neuronal cell injury. As a test of this hypothesis we have investigated the effect of external ion modulation on triethyllead neurotoxicity in cerebellar granule cell culture. Cultures were prepared from neonatal rats and used 10-20 days in vitro. Cytotoxicity was assessed by lactate dehydrogenase (LDH) release and trypan blue exclusion. A slow, dose-dependent (1-30 microM TEL) release of LDH occurred after a variable latent period dependent upon [TEL]. External replacement of [Cl-]e by Na isothionate dramatically shifted the dose response curve to the left reflecting an accelerated stimulation of LDH release, while replacement of extracellular [Na+]e with equimolar choline chloride had a minimal protective effect. Similarly, high [Mg2+]e or low [Ca2+]e did not protect or potentiate TEL cytotoxicity. The low [Cl-]e accelerated TEL cytotoxicity was dependent on medium pH: alkaline pH potentiated the cytotoxicity. Low [Cl-]e had no significant effect on culture ATP over 5 hrs. ATP reduction was markedly stimulated by TEL in low Cl- medium in contrast to the minimal decline in [ATP] in the control medium. The reduction of ATP in the low [Cl-]e medium occurred prior to LDH or trypan blue staining release confirming that such reduction in [ATP] was not secondary to cell damage. Substituting K sulfate or Na sulfate for the Cl(-)-free medium revealed marked loss of ATP without LDH release in control and TEL supplemented cultures. These observations provide supporting evidence for the role of an abnormal Cl- flux in mediating TEL-induced neurotoxic injury. Specifically, the membrane depolarization is proportional to the gradient imposed by Cl- efflux/OH influx, stimulated by low [Cl-]e. The rapid loss in ATP appeared early, was not a secondary reflection of neuronal damage but a result of a combination of increased ion flux at the plasma membrane, stimulation of Na+/K+ ATPase and direct TEL-induced inhibition of mitochondrial oxidative phosphorylation.

Adenosine Triphosphate↗
PubMed1975

Actinomycosis.

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Actinomycosis↗