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Biomedical subjects

S W Smith

Publications and source records attributed to S W Smith.

At least 19 recordsLinked to original sources
PubMed2001

Adverse events, including death, associated with the use of 1,4-butanediol.

BACKGROUND: 1,4-Butanediol is an industrial solvent that, when ingested, is converted to gamma-hydroxybutyrate, a drug of abuse with depressant effects, primarily on the central nervous system. After reports of toxic effects of gamma-hydroxybutyrate and its resultant regulation by the federal government, 1,4-butanediol and gamma-butyrolactone, another precursor of gamma-hydroxybutyrate and an industrial solvent, began to be marketed as dietary supplements. We investigated reports of toxic effects due to the ingestion of 1,4-butanediol and reviewed the related health risks. METHODS: From June 1999 through December 1999, we identified cases of toxic effects of 1,4-butanediol involving patients who presented to our emergency departments with a clinical syndrome suggesting toxic effects of gamma-hydroxybutyrate and a history of ingesting 1,4-butanediol and patients discovered through public health officials and family members. We used gas chromatography-mass spectrometry to measure 1,4-butanediol or its metabolite, gamma-hydroxybutyrate, in urine, serum, or blood. RESULTS: We identified nine episodes of toxic effects in eight patients who had ingested 1,4-butanediol recreationally, to enhance bodybuilding, or to treat depression or insomnia. One patient presented twice with toxic effects and had withdrawal symptoms after her second presentation. Clinical findings and adverse events included vomiting, urinary and fecal incontinence, agitation, combativeness, a labile level of consciousness, respiratory depression, and death. No additional intoxicants were identified in six patients, including the two who died. The doses of 1,4-butanediol ingested ranged from 5.4 to 20 g in the patients who died and ranged from 1 to 14 g in the nonfatal cases. CONCLUSIONS: The health risks of 1,4-butanediol are similar to those of its counterparts, gamma-hydroxybutyrate and gamma-butyrolactone. These include acute toxic effects, which may be fatal, and addiction and withdrawal.

Adult↗
PubMed2000

Phase II trial evaluating triplet chemotherapy using gemcitabine, paclitaxel, and carboplatin in the treatment of patients with advanced non-small cell lung cancer.

The purpose of this study was to evaluate the combination of gemcitabine, paclitaxel, and carboplatin in patients with advanced non-small cell lung cancer. Previously untreated patients with stage IIIB or IV non-small cell lung cancer were enrolled into this trial. Sixty-nine patients from the phase II portion and eight patients from the phase I portion were treated with gemcitabine 1,000 mg/m2 intravenously on days I and 8, paclitaxel 200 mg/m2 as a 1-hour infusion on day 1, and carboplatin at an area under the curve of 5.0 intravenously on day 1. Treatment courses were repeated every 21 days. The phase II component of the study was completed at 13 community-based practices in the Minnie Pearl Cancer Research Network. Thirty-four of 71 fully evaluable patients had an objective response (48%, two complete and 32 partial responses). Twenty-five patients (35%) were stable and 12 (17%) progressed. The median response duration was 6 months (range, 3 to 14 months) and the median survival was 9.9 months, with 1- and 2-year survival rates of 47% and 21%, respectively. The combination of gemcitabine, paclitaxel, and carboplatin has been shown to be safe and effective; thus, this three-drug regimen will be compared with a standard two-drug regimen, paclitaxel/carboplatin, in a phase III study.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Phase I/II trial of paclitaxel by 1-hour infusion, carboplatin, and gemcitabine in the treatment of patients with advanced nonsmall cell lung carcinoma.

BACKGROUND: The combination of paclitaxel and carboplatin is widely used in the treatment of patients with advanced nonsmall cell lung carcinoma. In this Phase I/II study the authors evaluated the feasibility, toxicity, and efficacy of adding a third active antineoplastic agent, gemcitabine, to the paclitaxel/carboplatin combination for the treatment of patients with advanced nonsmall cell lung carcinoma. METHODS: Patients with advanced (AJCC Stage IIIB or IV) nonsmall cell lung carcinoma previously untreated with chemotherapy were eligible for this trial. The maximum tolerated doses, determined in the Phase I trial and subsequently used in the Phase II trial, were: paclitaxel, 200 mg/m2, as a 1-hour infusion on Day 1; carboplatin, at area under the curve dose of 5.0 intravenously (i.v.), on Day 1; and gemcitabine, 1000 mg/m2 i.v., on Days 1 and 8. Treatment courses were repeated every 21 days. The Phase II study was conducted in 13 community-based practices in the Minnie Pearl Cancer Research Network; 77 patients were treated between December 1996 and September 1997. RESULTS: Thirty-four of 77 patients (44%) in the Phase II trial had major responses (partial responses, 32 patients and complete responses, 2 patients). An additional 25 patients (33%) had stable disease or minor response; only 23% of patients progressed or were removed from study at or prior to first reevaluation. The median survival was 9.4 months, with a 45% actuarial 1-year survival rate. Myelosuppression was the most common toxicity, with Grade 3/4 NCI Common Toxicity Criteria leukopenia and thrombocytopenia in 49% and 45% of patients, respectively. However, only 11 patients (14%) required hospitalization for neutropenia/ fever, and none had bleeding complications. Grade 3/4 nonhematologic toxicities included fatigue (41%), arthralgias/myalgias (26%), peripheral neuropathy (8%), nausea/emesis (6%), and hypersensitivity reactions (4%). There was one treatment-related death due to sepsis. CONCLUSIONS: This three-drug regimen is active and has acceptable toxicity in patients with advanced nonsmall cell lung carcinoma. Myelosuppression, particularly thrombocytopenia, is increased in comparison to the paclitaxel/carboplatin regimen. Fatigue also may be increased, but other nonhematologic toxicities are not altered substantially by adding gemcitabine. Although the response rate and median survival are improved modestly compared with our previous experience with paclitaxel/carboplatin, definitive conclusions regarding the efficacy of this regimen await the completion of randomized trials.

Adult↗
PubMed1999

Living with cerebral palsy and tube feeding: A population-based follow-up study.

OBJECTIVES: To assess the impact of surgically placed feeding tubes on children with severe cerebral palsy (CP) and their families and to determine the survival of these children after initiation of tube feeding (TF). METHODS: Virtually all children from Nova Scotia who had gastrostomy or jejunostomy procedures between the years 1980 and 1998 and who had been diagnosed with CP were identified. Caretakers of those children who had TF initiated in the last 8 years were evaluated by using a semi-structured interview. Names of children who had not had recent follow-up visits were submitted to the provincial Vital Statistics office to determine whether they had died. Data from patients who were tube-fed between 1980 and 1989 were then used in combination with data from the more recent cases to create a survival curve. RESULTS: A total of 61 children were identified; 16 had died. Forty of 45 eligible families were interviewed; 90% were pleased with the effect of TF on their child and family life. Negative reports were associated with increased stress related to feeding. Survival rates after gastrostomy and/or jejunostomy were 83% after 2 years and 75% after 7 years. CONCLUSIONS: In children with severe CF, initiation of TF improved the quality of life for both the child and family in 90% despite frequent minor complications.

Activities of Daily Living↗
PubMed1999

Orthodontic correction of a class III malocclusion in an adolescent patient with a bonded RPE and protraction face mask.

A case report of a 14-year-old Hispanic male with a Class-III skeletal profile and dental malocclusion with a long mandibular body and ramus and retrusive maxilla. The patient was initially referred for a surgical evaluation for a LeFort I maxillary advancement, but he wanted to avoid surgery. The Class-III malocclusion was corrected with a bonded rapid palatal expander and a maxillary protraction mask followed by nonextraction orthodontic treatment. A Class-I molar and canine relationship was achieved, and the facial profile improved. This case report demonstrates the orthodontic correction of a Class-III malocclusion in an adolescent patient with a bonded rapid palatal expander and protraction face mask. This case was presented to American Board of Orthodontics as partial fulfillment of the requirements for the certification process conducted by the Board.

Adolescent↗
PubMed1999

Evaluation of the consolidation period during osteodistraction using computed tomography.

The use of distraction osteogenesis offers an alternative approach to the correction of craniofacial deformities. However, little is known with respect to the appropriate length of the consolidation period for the newly formed bone. The objective of this study was to evaluate, by quantitative computed tomography, the regenerate bone produced during osteodistraction of the dog mandible at three different consolidation times. Twelve skeletally mature male beagle dogs were equally separated into three experimental groups. Each dog underwent 10 mm of bilateral distraction osteogenesis to lengthen the mandible. After the distraction period, the bone was allowed to consolidate for 4, 6, or 8 weeks, at which time the animals were sacrificed and the mandibles harvested for computed tomographic imaging. The results demonstrate a significantly lower mean bone density of the regenerate in the 4 week group when compared with either the 6 or 8 week groups (P < .01). There was no significant difference, however, in mean bone density between the 6 and 8 week groups.

Animals↗
PubMed1999

Immunization practices and beliefs of physicians in suburban Cook County, Illinois.

This study was conducted to ascertain the vaccination beliefs and practices of physicians who provide care for low income children. Sixty-two (56.9%) of a sample of 109 physicians in suburban Cook County, Illinois responded to a mail survey. A majority of physicians reported a willingness to immunize during well child care, follow-up, and chronic illness visits; yet, a substantial lack of willingness to immunize given certain acute mild illnesses was reported. Twenty-six percent of providers did not routinely identify children who were behind in immunizations and only 16% had completed a chart audit in the past three years. Seventy-four percent were willing to provide all shots needed at a single visit. Misconceptions regarding true contraindications was found among the group. Missed well child visits were identified as the greatest barrier to complete immunization. Improvements in vaccination rates are expected if physicians utilize all types of medical encounters to monitor the immunization status of patients and provide vaccines using only true medical contraindications.

Adult↗
PubMed1999

A preschool immunization project to enhance immunization levels, the public-private relationship, and continuity of care.

This study was conducted to determine whether implementing a program aimed at providing a variety of incentives to physicians who provide immunizations to preschool-aged children would help to improve immunization rates and reduce fragmented care for patients. Twenty physicians from 14 private practices that provide care to preschool-aged children from low income families in suburban Cook County, Illinois participated in the project. A randomly selected subset of patient case records from the physicians' offices were audited after the implementation of the project to determine the immunization status of children in the practices and the nature of services provided. These 310 records of children under three years of age who were treated between 1991-1994 (the intervention sample) were compared to 310 charts from a 1988-1990 cohort of records (baseline sample). The groups did not differ on race or gender; however, significantly more families in the 1988 through 1990 cohort of children under 3 years of age were insured privately when compared to the 1991 through 1994 cohort. Seventy percent (218) of the records in the intervention sample were up to date for age on immunizations compared to 45% (141) of the baseline records, reflecting a statistically significant difference (p < .00001). The intervention sample showed significantly more well child visits where immunizations were given and follow up visits where immunizations were given when compared to the baseline sample. Physicians completed surveys before and after implementation of the project. They were questioned about their knowledge and practices regarding immunizations as well as their opinion of specific project components. All of the physicians viewed the project as an effective means to improve immunization services to low income children. The project demonstrates a potential means of enhancing immunization levels and continuity of care among preschool-aged children. It also highlights the workable nature of the partnership between public and private sectors.

Child Health Services↗
PubMed1999

Metabolic acidosis in restraint-associated cardiac arrest: a case series.

The mechanism of death in patients struggling against restraints remains a topic of debate. This article presents a series of five patients with restraint-associated cardiac arrest and profound metabolic acidosis. The lowest recorded pH was 6.25; this patient and three others died despite aggressive resuscitation. The survivor's pH was 6.46; this patient subsequently made a good recovery. Struggling against restraints may produce a lactic acidosis. Stimulant drugs such as cocaine may promote further metabolic acidosis and impair normal behavioral regulatory responses. Restrictive positioning of combative patients may impede appropriate respiratory compensation for this acidemia. Public safety personnel and emergency providers must be aware of the life threat to combative patients and be careful with restraint techniques. Further investigation of sedative agents and buffering therapy for this select patient group is suggested.

Acidosis↗
PubMed1998

Radiologists' review of radiographs interpreted confidently by emergency physicians infrequently leads to changes in patient management.

STUDY OBJECTIVE: To determine whether radiologists' review of radiographs is unwarranted when emergency physicians are confident in their interpretations. METHODS: This was a prospective, descriptive study. Treating emergency physicians at a high-volume, urban teaching hospital and a moderate-volume nonteaching hospital indicated their confidence or lack of confidence in their plain-film radiographic study interpretations. All radiographs were then reviewed by radiologists according to the preexisting practice of each hospital. A total of 16,410 emergency department radiographic studies were included, comprising consecutive patients at each hospital. Charts of all discordant readings in the confident group were reviewed and judged clinically significant if treatment was altered. Charges for radiologic review of the confident ED interpretations were calculated. RESULTS: The ED physicians were confident in 9,599 sets of radiographs out of a total of 16,410 (58%). Discordant interpretation rates for the "confident" and "not confident" groups were 1.2% and 3.1%, respectively (difference, 1.9%; 95% confidence interval [CI] of the difference, 1.44% to 2.36%). Review of the 118 discordant interpretations in the confident group demonstrated that 11 were significant. Few management changes were made as a result of radiologists' review of these radiographs. Total radiology review charges for the confident group were $215,338. Therefore the average radiology charge for each significant discordant interpretation was $19,576. CONCLUSIONS: Of 9,599 sets of radiographs interpreted confidently by the emergency physicians in this study, there were 11 clinically significant discordant interpretations (0.1%). The standard practice of radiologists' review of all ED radiographs may not be justifiable.

Attitude of Health Personnel↗
PubMed1998

Severe sepsis in the emergency department and its association with a complicated clinical course.

OBJECTIVE: Infection severity as determined by clinical criteria has been recently classified and studied in hospitalized inpatients. The objective of the study was to use modified criteria to determine the clinical course associated with three levels of infection severity in infected patients admitted from the ED. METHODS: This was a retrospective cohort study involving all patients 18 years of age and older admitted through the ED of an urban teaching hospital during a four-month period whose primary reason for requiring hospitalization was an infection that was recognized in the ED. ED records were reviewed for criteria used to classify patients by three levels of infection severity: no systemic inflammatory response syndrome, sepsis, and severe sepsis (SS). The relationships between these classifications as well as certain clinical characteristics and any complicated clinical course as measured by death and/or admission to an intensive care unit (ICU), and/or prolonged hospitalization, were analyzed. RESULTS: Of 408 patients entered into the study, 138 (33.8%) fulfilled the criteria of SS in the ED. Patients with SS in the ED had a mortality of only 4.3%, though with an increased risk of dying compared with that of the other groups combined [relative risk (RR) = 11.64, 95% confidence interval (CI) = 1.43 to 96.53], an increased risk of ICU stay (RR = 7.65, 95% CI = 4.08 to 14.36), and an increased risk of prolonged hospitalization (RR = 1.99, 95% CI = 1.38 to 2.88). Although age over 60 years and several comorbid conditions also were identified by univariate analysis as risk factors, multivariate analysis revealed that only SS and diabetes mellitus (DM) were independent predictors of a complicated course. In the authors' institution, the positive predictive value (PPV) of SS for complicated clinical course was 0.48 and the negative predictive value (NPV) of no SS for no complicated course was 0.77. The PPV of [SS + DM] was 0.83, and the NPV of [SS, DM, or both] was also 0.83. CONCLUSION: Although the strongest correlate of a complicated clinical course identified in the ED is SS as defined by the study criteria, its specificity and PPV are low. The mortality of ED patients with SS is much lower than the mortality rates reported for inpatients with SS. SS as defined by the study criteria is too sensitive and therefore lacks utility in the ED setting.

Adult↗
PubMed1998

Progress in two-dimensional arrays for real-time volumetric imaging.

The design, fabrication, and evaluation of two dimensional array transducers for real-time volumetric imaging are described. The transducers we have previously described operated at frequencies below 3 MHz and were unwieldy to the operator because of the interconnect schemes used in connecting to the transducer handle. Several new transducers have been developed using new connection technology. A 40 x 40 = 1,600 element, 3.5 MHz array was fabricated with 256 transmit and 256 receive elements. A 60 x 60 = 3,600 element 5.0 MHz array was constructed with 248 transmit and 256 receive elements. An 80 x 80 = 6,400 element, 2.5 MHz array was fabricated with 256 transmit and 208receive elements. 2-D transducer arrays were also developed for volumetric scanning in an intra cardiac catheter, a 10 x 10 = 100 element 5.0 MHz forward-looking array and an 11 x 13 = 143 element 5.0 MHz side-scanning array. The-6dB fractional bandwidths for the different arrays varied from 50% to 63%, and the 50 omega insertion loss for all the transducers was about-64 dB. The transducers were used to generate real-time volumetric images in phantoms and in vivo using the Duke University real time volumetric imaging system, which is capable of generating multiple planes at any desired angle and depth within the pyramidal volume.

Cardiac Volume↗
PubMed1998

Ultrasonic imaging using optoelectronic transmitters.

Conventional ultrasound scanners utilize electronic transmitters and receivers at the scanner with a separate coaxial cable connected to each transducer element in the handle. The number of transducer elements determines the size and weight of the transducer cable assembly that connects the imaging array to the scanner. 2-D arrays that allow new imaging modalities to be introduced significantly increase the channel count making the transducer cable assembly more difficult to handle. Therefore, reducing the size and increasing the flexibility of the transducer cable assembly is a concern. Fiber optics can be used to transmit signals optically and has distinct advantages over standard coaxial cable to increase flexibility and decrease the weight of the transducer cable for larger channel numbers. The use of fiber optics to connect the array and the scanner entails the use of optoelectronics such as detectors and laser diodes to send and receive signals. In transmit, optoelectronics would have to be designed to produce high-voltage wide-bandwidth pulses across the transducer element. In this paper, we describe a 48 channel ultrasound system having 16 optoelectronic transmitters and 32 conventional electronic receivers. We investigated both silicon avalanche photodiodes (APD's) and GaAs lateral photoconductive semiconductor switches (PCSS's) for producing the transmit pulses. A Siemens SI-1200 scanner and a 2.25 MHz linear array were used to compare the optoelectronic system to a conventional electronic transmit system. Transmit signal results and images in tissue mimicking of cysts and tumors are provided for comparison.

Fiber Optic Technology↗