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Biomedical subjects

R A Thisted

Publications and source records attributed to R A Thisted.

At least 19 recordsLinked to original sources
PubMed1998

SPECT brain imaging in epilepsy: a meta-analysis.

UNLABELLED: A meta-analysis of SPECT brain imaging in epilepsy was performed to derive the sensitivity and specificity of interictal, postictal or ictal rCBF patterns to identify a seizure focus in medically refractory patients. METHODS: Papers were obtained by pooling all published articles identified by two independent literature searches: (a) Dialnet (EMBASE) or Radline by CD-ROM and (b) Current Contents searched manually. Literature inclusion criteria were: (a) patients had a localization-related epileptic syndrome; (b) more than six patients were reported; and (c) patients had at least an interictal EEG-documented epileptiform abnormality. Of 46 papers meeting these criteria, 30 contained extractable data. SPECT results were compared to localization by standard diagnostic evaluation and surgical outcome. Meta-analytic sensitivities for SPECT localization in patients with temporal lobe seizures relative to diagnostic evaluation were 0.44 (interictal), 0.75 (postictal) and 0.97 (ictal). Similar results were obtained relative to surgical outcome. False-positive rates were low relative to diagnostic evaluation (7.4% for interictal and 1.5% for postictal studies) and surgical outcome (4.4% for interictal and 0.0% for postictal studies). RESULTS: The results were not dependent on tracer used (or dose), the presence of CT-identified structural abnormalities, blinding of image interpretation or camera quality (although data were more variable with low-resolution cameras). There were insufficient data for conclusions regarding extratemporal-seizure or pediatric epilepsy populations. CONCLUSION: Insights gained from reviewing this literature yielded recommendations for minimal information that should be provided in future reports. Additional recommendations regarding the nature and focus of future studies also are provided. The most important of these is that institutions using SPECT imaging in epilepsy should perform ictal, preferably, or postictal scanning in combination with interictal scanning.

Brain↗
PubMed1998

Is geographic variation in hip fracture rates related to current or former region of residence?

This study examines geographic variation in male and female age-adjusted hip fracture rates in white elderly Medicare enrollees. We assembled a cohort of more than 2 million 1992 enrollees and followed them passively through record linkage for 2 years for a hospitalization containing a diagnostic code indicating hip fracture. We simultaneously estimated rate ratios by region of residence early (inferred from the Social Security number) and late in life. Residence region early in life is associated with substantial variation in hip fracture rates. Conversely, current region has little relation with hip fracture risk.

Aged↗
PubMed1997

Postcesarean analgesia with both epidural morphine and intravenous patient-controlled analgesia: neurobehavioral outcomes among nursing neonates.

UNLABELLED: Among nursing parturients after cesarean delivery, intravenous patient-controlled analgesia (PCA) with meperidine is associated with significantly more neonatal neurobehavioral depression than PCA with morphine. A single dose of epidural morphine (4 mg) decreases postcesarean opioid analgesic requirements and may reduce or prevent neonatal neurobehavioral depression associated with PCA meperidine. Prospectively, 102 term parturients underwent cesarean delivery with epidural anesthesia, 2% lidocaine and epinephrine 1:200,000. After umbilical cord clamping, each patient received epidural morphine 4 mg and was randomly allocated to receive either PCA meperidine or PCA morphine. Initial neonatal characteristics, included gestational age, Apgar scores, weight, and umbilical cord gas partial pressures. Brazelton Neonatal Behavioral Assessment Scale (NBAS) examinations were performed on each of the first 4 days of life. Nursing infants (n = 47) were grouped according to maternal PCA opioid in breast milk (meperidine [n = 24] or morphine [n = 23]); bottle-fed infants (n = 56) served as the control group. The three infant groups were equivalent with respect to initial characteristics and NBAS scores on the first 2 days of life. On the third day of life, infants in the morphine group were significantly more alert and oriented to animate human cues compared with infants in the meperidine or control group. On the fourth day of life, infants in the morphine group remained significantly more alert and oriented to animate human auditory cues than infants in the meperidine group. Average PCA opioid consumption through 48 h postpartum was equivalent (0.54 mg/kg morphine and 4.7 mg/kg meperidine); however, even with these small doses, meperidine was associated with significantly poorer neonatal alertness and orientation than morphine. Morphine is the PCA opioid of choice for postcesarean analgesia among nursing parturients. IMPLICATIONS: Among nursing parturients after cesarean delivery, intravenous patient-controlled analgesia with meperidine is associated with more neonatal neurobehavioral depression than patient-controlled analgesia with morphine. In this study, we found that nursing infants exposed to morphine were more alert and oriented to animate human cues than those exposed to meperidine.

Adult↗
PubMed1997

Results of radical prostatectomy in men with locally advanced prostate cancer: multi-institutional pooled analysis.

OBJECTIVE: We investigated the disease-specific and metastasis-free survival rates in men with locally advanced (clinical stage T3) prostate cancer who were treated surgically. METHODS: A retrospective, multi-institutional pooled analysis of the results of surgical treatment in 345 men with clinical stage T3 disease was performed. Survival curves were generated using the Kaplan-Meier method. RESULTS: Among 298 evaluable patients, pelvic lymphadenectomy alone was performed in 56 men (19%), while 242 men (81%) underwent node dissection and radical prostatectomy. In total, 122 of 298 patients (41%) had nodal metastases and/or seminal vesicle tumor spread. Pathologically organ-confined disease was noted in 27 men (9%). The actuarial 10-year disease-specific and metastasis-free survival rates for all patients managed surgically were 57 and 32%, respectively. For patients with well, moderately and poorly differentiated tumors, cancer-specific survival rates at 10 years were 73, 67 and 29%, respectively. CONCLUSIONS: A large number of men with clinical stage T3 prostate cancer have advanced disease and are unlikely to achieve improved long-term survival with surgery alone. Although there may be a role for radical prostatectomy in selected patients with low to intermediate grade tumors, such treatment appears unlikely to result in long-term survival in men with high grade disease. A prospective study is necessary to determine the optimal treatment approach in men with locally advanced prostate cancer.

Adult↗
PubMed1996

Results of radical prostatectomy in men with clinically localized prostate cancer.

OBJECTIVE: To assess the results of radical prostatectomy in men with early prostate cancer. DESIGN: Retrospective, nonrandomized, multi-institutional pooled analysis. SETTING: Eight university medical centers in the United States and Europe. PATIENTS: A total of 2758 men with stage Tl and T2 prostatic cancer. MAIN OUTCOME MEASURES: Disease-specific and metastasis-free survival rates. RESULTS: Tumor grade was the most important preoperative factor in determining outcome. Disease-specific survival 10 years following surgery and associated 95% confidence intervals were 94% (range, 87%-98%), 80% (range, 74%-85%), and 77% (range, 65%-86%) for those men with grade 1, 2, and 3 tumors, respectively. Metastasis-free survival at 10 years was 87% (range, 78%-92%), 68% (range, 62%-73%), and 52% (range, 38%-64%) for patients with grade 1, 2, and 3 cancers, respectively. CONCLUSIONS: Radical prostatectomy leads to high 10-year disease-specific survival rates in men with all tumor grades. However, caution is needed in comparing these results with similar studies of alternative treatment strategies, such as watchful waiting, due to the inherent potential biases in uncontrolled trials. Nevertheless, these results offer the best currently available estimates of 10-year outcome of radical prostatectomy in men with clinically localized prostate cancer and may be useful in counseling patients with early malignancy.

Europe↗
PubMed1996

Eye injuries after nonocular surgery. A study of 60,965 anesthetics from 1988 to 1992.

BACKGROUND: Eye injuries after anesthesia, although infrequent, may result in visual impairment. Previous studies have not defined the risk factors associated with these injuries. To study the cause of these injuries and to determine incidence data, the authors reviewed the records from a 4.5-y period of patients who sustained eye injuries after anesthesia and nonocular surgery. METHODS: The records were surveyed of 60,965 patients who underwent anesthesia for nonocular surgery at our institution from January 1988 to July 1992. Eye injuries were identified by examining several sources of information, including quality improvement data, postoperative visits or telephone calls, and examination of medical records of postoperative patients who required an ophthalmology consultation. Records were reviewed to determine the types and causes of eye injuries. Logistic regression, with univariate and multivariate analysis, was used to identify the importance of possible risk factors. RESULTS: Of 34 patients who sustained eye injuries (0.056%), the most common was corneal abrasion (n = 21). Other injuries were conjunctivitis, blurred vision, red eye, chemical injury, direct trauma, and blindness. Independent factors associated with a higher relative risk of eye injury were long surgical procedures (odds ratio, 1.16 per hour of anesthetic care; CI, 1.1 to 1.3), lateral positioning during surgery (odds ratio, 4.7; CI, 2 to 11), operation on the head or neck (odds ratio, 4.4; CI, 2.2 to 9.0), general anesthesia (odds ratio, 3.0; CI, 2.2 to 38), and surgery on a Monday (odds ratio, 2.7; CI, 1.4 to 5.3). In only 21% of cases was a specific cause of injury identified. CONCLUSIONS: For reasons not understood, eye injuries are more common in patients who are older or who undergo lengthier procedures. The cause of injury was usually not determined by the authors' methods. Until the mechanisms producing perioperative eye injuries are better understood, it is difficult to identify strategies to prevent this type of injury.

Adult↗
PubMed1995

Short-term outcomes after cryosurgical ablation of the prostate in men with recurrent prostate carcinoma following radiation therapy.

OBJECTIVES: Cryosurgical ablation of the prostate represents a possibly efficacious method of treating prostate carcinoma in men failing radiation therapy. In addition to eradicating the disease, cryosurgery has the potential to avoid some of the morbidity associated with other treatment modalities. Therefore, a prospective Phase II trial was conducted to determine the safety and efficacy of cryosurgery following radiation therapy in men with local recurrence. METHODS: Cryosurgical ablation of the prostate was performed in men with prostate cancer previously treated by radiation therapy. All patients had biopsy-proven recurrent disease and no evidence of metastases. Initial follow-up occurred at approximately 3 months and included repeat biopsy and serum prostate-specific antigen (PSA) determinations. Biochemical disease-free survival defined as a PSA value less than 0.3 ng/mL was assessed using the Kaplan-Meier method. RESULTS: Thus far, 23 patients have been treated with cryosurgery with follow-up ranging between 12 and 23 months. Approximately 3 months after treatment, sextant biopsies revealed no cancer in 19 of 22 (86%) of the specimens; however, 10 of 22 (45%) showed small amounts of benign glandular tissue. The PSA at 3 months postoperatively declined in 18 of 22 (82%) patients but reached female levels in only 8 men (36%). Nineteen of 22 (86%) patients followed up a minimum of 1 year after cryotherapy have a PSA level equal to or greater than 0.3 ng/mL. Complications occurred in 100% of the patients with 12 of 22 (55%) requiring at least one transurethral resection of sloughed, necrotic tissue. CONCLUSIONS: Our preliminary results suggest that the current cryosurgical technique used in men failing radiation therapy has a low probability of biochemical cure and a high complication rate. Until more data are available, cryosurgery for men with locally recurrent disease after radiation therapy should be considered strictly experimental.

Aged↗
PubMed1995

Prospective, randomized, double-blind trial of BQ-123 and bosentan for prevention of vasospasm following subarachnoid hemorrhage in monkeys.

Thirty-one monkeys were randomly divided into three groups to undergo baseline cerebral angiography followed by induction of subarachnoid hemorrhage by placement of autologous blood clot along the right-sided arteries of the anterior circle of Willis (Day 0). The monkeys were then given drug vehicle or one of two endothelin (ET) antagonists, BQ-123 (6 mg/kg/day) or bosentan (5 mg/kg/day) intracisternally. The BQ-123 was administered by continuous infusion from a subcutaneous pump and the bosentan was given by twice-daily injections into an Ommaya reservoir in the subcutaneous space with a catheter along the right middle cerebral artery (MCA). Seven days later (Day 7), angiography was repeated and the animals were killed. Comparison of arterial diameters shown on angiograms between Day 0 and Day 7 groups given placebo and bosentan showed significant reductions in the diameters of the right intradural internal carotid (28% +/- 6% and 30% +/- 6%, respectively, paired t-test, p < 0.05), anterior cerebral artery (29% +/- 8% and 32% +/- 6% respectively +/- 6%, respectively) and MCA (34% +/- 6% and 46% +/- 4%, respectively). Animals injected with BQ-123 had significant narrowing of the right extradural internal carotid artery (7% +/- 6%) and the basilar artery (11% +/- 3%), but not of the right MCA. Comparison of arterial diameters between groups at Day 7 showed significant variance in the right extradural internal carotid, both intradural internal carotid, right middle cerebral, and left anterior cerebral arteries; the animals injected with BQ-123 developed significantly less arterial narrowing these those receiving bosentan and placebo. Bosentan was not detected in the cerebrospinal fluid aspirated from the cisterna magna on Day 7, whereas BQ-123 was detected in two animals. We can infer from these results that BQ-123 prevents vasospasm following subarachnoid hemorrhage in monkeys, that further investigations of ET antagonists are warranted, and that ET may be an important pathophysiological mediator of vasospasm. The lack of efficacy of bosentan may be related to inadequate cerebrospinal fluid levels obtained by administration twice-daily through an Ommaya reservoir.

Analysis of Variance↗
PubMed1995

Estimation of the association between desipramine and the risk for sudden death in 5- to 14-year-old children.

BACKGROUND: Four cases of sudden death in children 12 years or younger during desipramine treatment were identified between 1986 and 1992. We evaluated whether these events support the hypothesis that exposure to therapeutic doses of desipramine contributes to the risk for sudden death in otherwise healthy children. METHOD: The National Center for Health Statistics provided the baseline number of sudden unexplained deaths in children 5 to 14 years old. Data from the National Disease and Therapeutic Index were used to estimate the exposure to desipramine in children in the same age group. Since two of the four deaths were identified by 1987, we used the post-1987 experience as if it were a prospective period in which a causal association could be examined. RESULTS: The number of sudden deaths in desipramine-exposed children did not increase from 1986 to 1992 despite a marked increase in exposure. By using 4 to 6 months as the average lifetime of a desipramine prescription and a baseline rate of sudden death of 4.2 deaths/million/year in this population, the post-1987 period would account for 162,000 to 242,000 person-years of desipramine exposure. Although not statistically significant, this level of exposure corresponds to a relative risk of 2.1 (95% CI = 0.5 to 15) to 3.1 (95% CI = 0.8 to 22). CONCLUSION: Although, based on our estimates, the evidence for an association between desipramine and sudden death in children aged 5 to 14 years appears weak, replication of our findings is needed with a more precise numerator (total number of deaths) and denominator (the appropriate conversion from drug appearance to actual exposure) before a firm conclusion on this subject can be drawn. Until then, even if remote, the possibility of an association between desipramine and sudden death in children stresses the importance of assessing risks and benefits when desipramine is used in pediatric patients.

Adolescent↗
PubMed1994

Results of conservative management of clinically localized prostate cancer.

BACKGROUND: The selection of treatment for patients with localized prostate cancer requires reliable information about the outcome of conservative management. Previous studies of this question are generally considered unreliable because they were uncontrolled and nonrandomized. METHODS: We performed a pooled analysis of 828 case records from six nonrandomized studies, published since 1985, of men treated conservatively (with observation and delayed hormone therapy but no radical surgery or irradiation) for clinically localized prostate cancer. A Cox regression analysis was performed to determine which factors influenced survival among patients who did not die of causes other than prostate cancer (disease-specific survival). Kaplan-Meier curves for overall and metastasis-free survival among such patients were compared with use of the log-rank method and the Mantel-Haenszel test. RESULTS: Factors that had a significant effect on disease-specific survival were grade 3 tumors (risk ratio, 10.04), residence in Israel (risk ratio, 2.48) or New York (risk ratio, 0.37), and age under 61 years (risk ratio, 0.32). Ten years after diagnosis, disease-specific survival (with data on men who died from causes other than prostate cancer censored) was 87 percent for men with grade 1 or 2 tumors and 34 percent for those with grade 3 tumors; metastasis-free survival among men who had not died of other causes was 81 percent for grade 1, 58 percent for grade 2, and 26 percent for grade 3 disease. These findings were not affected by the inclusion of men who had early-stage cancer, were older, had worse-than-average health, or underwent delayed radiation therapy or radical prostatectomy. CONCLUSIONS: The strategy of initial conservative management and delayed hormone therapy is a reasonable choice for some men with grade 1 or 2 clinically localized prostate cancer, particularly for those who have an average life expectancy of 10 years or less. New treatment strategies are needed for men with grade 3 prostate cancer.

Aged↗
PubMed1994

Mucosal allergy in the absence of systemic allergy in nasal polyposis and rhinitis: a meta-analysis.

To better determine the role of allergy in rhinitis and nasal polyposis, we assessed the prevalence of nasal mucosal allergy in the absence of systemic allergy. After a thorough literature search we compiled and analyzed data from nine studies (287 patients) that tested for specific immunoglobulin E both intranasally and systemically. When meta-analysis was applied to the different populations, 19% of those who demonstrated specific immunoglobulin E manifested nasal mucosal allergy but no systemic allergy. We suggest that there is an important segment of rhinitis and nasal polyp patients who have nasal mucosal allergy.

Humans↗
PubMed1994

Predictive and diagnostic tests of renal failure: a review.

Postoperative acute renal insufficiency is a discouraging complication with a mortality rate that remains persistently high, despite improved techniques of dialysis and advances in the perioperative management of hemodynamic, metabolic, and infective complications. A complete understanding of the role of renal hemodynamics in the pathophysiology of acute renal failure still has not emerged. Serial determination of creatinine clearance is currently the most sensitive test for predicting the onset of perioperative renal dysfunction; however, the test is not practical for measuring renal function under operating room conditions. Furthermore, testing creatinine clearance is time-consuming, labor intensive, and may cause significant delay in identifying the onset of renal dysfunction. That early therapy modifies the prognosis of renal dysfunction remains an untested hypothesis until a measurement that predicts renal outcome is found that is sensitive, specific, and easily obtainable. The ability to measure intrarenal blood flow distribution may offer promise for improving our predictive and diagnostic abilities to assess perioperative acute renal failure. Methodologic constraints, however, limit the practicality of this measurement in the perioperative setting at this time. Instead, we rely on indirect variables that do not bear a reliable relationship to glomerular filtration rate and renal function.

Acute Kidney Injury↗
PubMed1994

Association of preoperative risk factors with postoperative acute renal failure.

We performed a systematic review of 28 studies that examined preoperative risk factors for postoperative renal failure. Included in the studies were 10,865 patients who underwent either vascular, cardiac, general, or biliary surgery. No two studies used the same criteria for acute renal failure. Variability in definitions of renal failure, lack of consistent criteria for establishing risk factors, and nonuniformity in the statistical methods employed result in a literature that is not adequate to support a comprehensive quantitative review. Of the 30 variables considered in the studies, preoperative renal risk factors, such as increased serum creatinine, increased blood urea nitrogen, and preoperative renal dysfunction were repeatedly found to predict postoperative renal dysfunction. The literature provides little quantitative information concerning the degree of risk associated with other factors. Cardiac risk factors, such as left ventricular dysfunction, were reported to be predictive of postoperative renal failure more consistently than was advanced age.

Acute Kidney Injury↗
PubMed1994

Relative effectiveness of four preoperative tests for predicting adverse cardiac outcomes after vascular surgery: a meta-analysis.

Various noninvasive tests have been proposed to stratify perioperative cardiovascular risk, including dipyridamole thallium scintigraphy (DTS), ejection fraction estimation by radionuclide ventriculography (RNV), ischemia monitoring by ambulatory electrocardiography (AECG), and dobutamine stress echocardiography (DSE). Which of these tests is most effective for predicting adverse perioperative cardiac outcome? To answer this question, and also to stimulate future studies, we evaluated 56 studies examining one or more of the four tests. We conducted meta-analysis on 20 studies that met the inclusion criteria. Outcome measures evaluated were cardiac death or myocardial infarction occurring during hospital stay or within 1 mo after surgery. Relative risk (RR), which is the probability of adverse cardiac outcome when the test is positive divided by the probability of adverse outcome when the test is negative, was used to combine evidence from different studies. An empirical Bayes procedure with a normal-normal hierarchic model was then used to obtain a meta-analytic confidence interval for the overall median of the relative risks. The between-study variance was estimated using the method of moments approach described by DerSimonian and Laird (Controlled Clin Trials 1986;7:177-88). Combined (median) RR [95% confidence interval (CI)] and the number of studies included in our meta-analysis for different evaluative tests were as follows: DTS 4.6 (2.1-10.4) (n = 6); RNV 3.7 (1.6-8.3) (n = 5); AECG 2.7 (1.4-5.1) (n = 6), and DSE 6.2 (1.7-22.8) (n = 3). We conclude that while DTS, RNV, AECG, and DSE are effective (the 95% CIs are greater than 1.0) in predicting the cardiac outcome after vascular surgery, the data are not definitive in determining the optimal test (95% CIs for RR overlap). Future studies should include DSE, as this test shows great promise for predicting adverse cardiac events after vascular surgery.

Coronary Angiography↗
PubMed1993

The interaction between alcohol and the residual effects of thiopental anesthesia.

BACKGROUND: During ambulatory surgery, barbiturates, such as thiopental, may impair psychomotor performance several hours after administration. It was hypothesized that if patients drink alcohol 4 h after thiopental injection, the increase in psychomotor impairment would be greater than that seen after alcohol ingestion alone. METHODS: Twelve healthy men volunteered to participate in a double-blind, placebo-controlled, crossover study with a Latin square design. On each testing day, the subjects received intravenous injections of either 5 mg/kg of 2.5% thiopental or an equal volume of saline for 30 s. Four hours after injection, the subjects consumed a beverage with or without 0.7 g/kg alcohol. Psychomotor performance and mood were assessed at five times: prior to injection, at 1 h and 3 h after injection, and at 1 h and 3 h after consumption of beverage. RESULTS: Both thiopental and alcohol had strong independent effects on the dependent measures in this study. In addition, body sway, one of the nine psychomotor tests used to assess impairment, was greater after thiopental and alcohol than after alcohol alone. Of eleven adjectives used to assess mood, lightheadedness was cited most frequently after a combination of thiopental and alcohol than after each alone. CONCLUSIONS: Based on our tests of performance and mood, an interaction between thiopental and alcohol is evident; in addition, the interaction between both drugs may exert deleterious effects on higher levels of central nervous system integration.

Adult↗
PubMed1993

The initial clinical experience of 1819 physicians in maintaining anesthesia with propofol: characteristics associated with prolonged time to awakening.

In October 1989, propofol underwent Phase IV Food and Drug Administration testing that involved 25,981 patients, 1722 institutions, and 1819 anesthesiologists. Participants were 18-80 yr of age and ASA physical status I-III; they could not have a continuing pregnancy or prior adverse anesthetic experience. Anesthesiologists completed detailed forms to describe their use of propofol in this three-step study: propofol for induction only (Step 1), for induction and then maintenance by intermittent bolus injection (Step 2), or for continuous infusion (Step 3). In early 1992, our group of anesthesiologists and epidemiologists analyzed the resulting data base. We evaluated data from 14,882 patients (8095 given bolus injections and 6787 given continuous infusion) to determine factors predicting prolonged time (> 15 min after cessation of all anesthesia) to awakening, one measure of recovery from anesthesia. The incidence of prolonged awakening was 6.8% (1016 patients); the median and mean (+/- SD) times to awakening were, respectively, 5 min and 7.2 +/- 7.3 min. The following variables were associated (P < 0.05) with prolonged awakening from propofol maintenance anesthesia: a total dose of propofol > 8 mg/kg, male gender, endotracheal intubation, age > 65 yr, abdominal surgery, continuous infusion of propofol, and concomitant use of isoflurane or benzodiazepines. These results support the clinical impression that recovery from propofol anesthesia is remarkably rapid; although the vast majority of physicians participating in this study were using propofol for maintenance for the first time, only 6.8% of patients had awakening times exceeding 15 min.

Adolescent↗