Biomedical subjects

L J Goldsmith

Publications and source records attributed to L J Goldsmith.

At least 37 records · Page 2Linked to original sources

PubMed1999

Effects of sevoflurane anaesthesia on recovery in children: a comparison with halothane.

We prospectively studied one hundred ASA physical status I-II children, ages six months to six years, undergoing myringotomy surgery. Children were randomly assigned to one of four anaesthetic groups receiving either halothane or sevoflurane for anaesthesia and oral midazolam premedication or no premedication. We found that children anaesthetized with sevoflurane had significantly faster recovery times and discharge home times than those who received halothane. Patients given oral midazolam premedication had significantly longer recovery times, but no delay in discharge home compared with those not premedicated. However, children anaesthetized with sevoflurane and no premedication had an unacceptably high incidence (67%) of postoperative agitation. The use of oral midazolam preoperatively did decrease the amount of postoperative agitation seen with sevoflurane. We conclude that although sevoflurane does shorten recovery times, the degree of associated postoperative agitation makes it unacceptable as a sole anaesthetic for myringotomy surgery.

Administration, Oral↗

PubMed1999

The effect of smoking on energy expenditure and plasma catecholamine and nicotine levels during light physical activity.

A number of studies have found that cigarette smoking causes an acute increase in resting energy expenditure, but the effect on energy expenditure during light physical activity is less clear. Since both smoking and activity have been shown to increase plasma catecholamines, these could produce additive effects on energy expenditure when smoking during light physical activity. In this study, the impact of cigarette smoking on energy expenditure, cardiovascular function, plasma nicotine and plasma catecholamine levels was determined in adult male subjects at rest and while engaged in light physical activity. Smoking at rest resulted in a 3.6% increase in energy expenditure above the resting baseline; whereas the increase in energy expenditure caused by smoking during light physical activity (compared with the light physical activity baseline) was 6.3%. This increase during light physical activity was significantly greater than the increase observed at rest (p < 0.025). As expected, plasma nicotine increased with smoking during both rest and light physical activity. An increase in plasma nicotine was associated with smoking during light physical activity. When this increase was adjusted as a covariate, the difference in smoking-related energy expenditure between light physical activity and rest disappeared, suggesting nicotine accounts for the effect. Plasma epinephrine and norepinephrine levels increased with smoking and showed a significantly greater increase during light physical activity compared to rest. Cigarette smoking caused a significantly greater increase in heart rate during light physical activity than it did while at rest, but there was no significant effect of smoking on mean blood pressure. It was concluded that there is enhanced energy expenditure associated with cigarette smoking during light physical activity when compared with smoking at rest which could be due in part to smoking-induced increases in circulating plasma catecholamines and perhaps nicotine.

Adult↗

PubMed1999

Transdermal nicotine patches do not cause clinically significant gastroesophageal reflux or esophageal motor disorders.

Transdermal nicotine delivery systems are widely used in smoking cessation. The purpose of this study was to determine whether common symptoms of pyrosis and dyspepsia associated with these patches are related to gastroesophageal reflux or esophageal dysmotility. Twenty-seven paid volunteer cigarette smokers (> 15 cigarettes/day) without symptomatic gastroesophageal reflux disease participated in this single-blinded, placebo-controlled study. Twenty subjects completed the study. Subjects underwent three sequential 24-h intraesophageal pH/motor studies (Synectics model T32342084, Shore View, MN). The pH/motility probe was positioned 5 cm above the manometrically determined LES. A placebo patch was applied for the first 24-h study and a 15-mg nicotine patch (Nicotrol) was applied for the initial 16 h (removed for remaining 8 h) of the second 24-h period. A 21-mg nicotine patch (Nicoderm) was applied for another 24-h study period. All subjects consumed an identical, defined diet documented by meal receipts, and refrained from smoking and tobacco use throughout the study periods (CO breath test confirmation). The Wilcoxon, paired t-test, exact McNemar statistical methods were used. The results showed that there were no significant differences in reflux symptoms (pyrosis, chest pain, nausea, dysphagia), supine gastroesophageal reflux (number of episodes, duration, or cumulative acid exposure), or the total number of reflux episodes between placebo and nicotine patch treatment periods. The number of post-prandial upright acid reflux episodes (p = 004) and number of upright acid reflux episodes lasting more than 5 min (p = 0.007) were statistically higher with the placebo patch compared to the active nicotine patches. No differences in intraesophageal pH or motility indices were noted between the two transdermal nicotine patches (Nicotrol, Nicoderm). It was concluded that dyspeptic symptoms in subjects utilizing transdermal nicotine patches are not related to gastroesophageal reflux or to esophageal motor abnormalities.

Administration, Cutaneous↗

PubMed1999

Radial head subluxation: comparing two methods of reduction.

OBJECTIVES: To determine whether reduction of radial head subluxation (RHS) is more successful using pronation and flexion (PF) vs the more widely used supination and flexion (SF) method. METHODS: Prospective study in a tertiary care children's hospital ED from August 1996 through December 1997. Inclusion criteria included age <7 years with an upper-extremity injury. Exclusion criteria included neurologic impairment, congenital malformation, or obvious bony deformity or edema. Patients were randomized to receive either PF or SF. Reduction was considered successful if the child used the injured arm. Both the physician and the parent rated the child's pain during the procedure using a descriptive ordinal scale, from 0 (no pain) to 3 (severe pain). RESULTS: 148 patients were enrolled; 13 were excluded. Success was achieved on the first attempt in 53/67 (80%, 95% CI = 0.67 to 0.88) of patients receiving PF and in 47/68 (69%, 95% CI = 0.57 to 0.80) of those receiving SF (p = 0.186). For those injuring the left arm, 29/41 (71%, 95% CI = 0.54 to 0.84) were successfully reduced using SF, while 33/37 (89%, 95% CI = 0.75 to 0.97) were successfully reduced using PF (p = 0.044). Physicians perceived PF to be less painful than SF (p = 0.013). There was no significant pain score difference rated by parents. CONCLUSIONS: Both PF and SF can be used with success to reduce RHS. For left arm injuries, PF should be attempted first, since it may decrease the need for further treatment. PF may be less painful, particularly for first reduction attempts.

Arthralgia↗

PubMed1999

Proposed changes to designations of medically underserved populations and health professional shortage areas: effects on rural areas.

This paper reports an analysis of the proposed rule to combine medically underserved population (MUP) and health professional shortage area (HPSA) designations, as published by the Bureau of Primary Health Care (BPHC) in the Federal Register on Sept. 1, 1998 (Department of Health and Human Services, 1998). The effects of the proposed rule overall and on rural communities were examined, particularly with respect to current whole county HPSA designations and eligibility for federal assistance programs. National, county-level estimates of primary care provider counts and other measures included in the proposed rule were used. Different primary care provider sources were compared; results were highly dependent on the data source and the inclusions of counts of nurse practitioners and physician assistants. The projections of losses from the proposed rule were higher than those of the BPHC, probably due to the use of different sources for provider counts. Overall, the authors projected that more than 50 percent of current whole-county HPSAs would lose designation using the proposed rule. The proportion of rural counties that lost designation was not significantly greater than the proportion of urban counties, but because there are many more rural counties, more de-designations were projected to occur in rural areas. The researchers also predicted that 58 percent of rural whole-county HPSAs with National Health Service Corps providers would lose their designation, but most rural whole-county HPSAs with Community and Migrant Health Centers or Rural Health Clinics retained their MUP designation using the proposed rule. The proposed rule likely has a larger effect on current designations than originally projected by the BPHC.

Data Interpretation, Statistical↗

PubMed1999

Comparison of lung function in infants exposed to maternal smoking and in infants with a family history of asthma.

STUDY OBJECTIVE: To compare lung function in infants exposed to maternal smoking with lung function in infants with a family history of asthma. There are no published studies comparing lung function in both groups. DESIGN: Cross-sectional study. SETTING: A tertiary pulmonary care center at a children's hospital. PATIENTS: One hundred five infants with daily wheezing. Thirty-five infants had persistent exposure to maternal smoking, and 70 had a family history of asthma in parents or siblings. MEASUREMENTS: Infant pulmonary function tests were compared between the two groups. The ratio of terminal to peak expiratory flow at tidal breathing at 25% of the previous expiration remaining and the ratio of terminal to peak expiratory flow with forced expiration at 25% of the previous expiration remaining (FEF25/PFEF) were used to evaluate peripheral airflow. A > 25% improvement in FEF25/PFEF after a bronchodilator challenge test was considered a positive response. RESULTS: Most infants in both groups had evidence of peripheral airflow obstruction with forced expiration. In infants exposed to maternal smoking, only 4 of 35 (11.4%) responded to a bronchodilator, compared to 51 of 70 (72.9%) in the group with a family history of asthma (p < 0.0005). There was no statistically significant difference in total respiratory system compliance, total respiratory system resistance, tidal volume, and degree of peripheral airflow obstruction at tidal breathing or after forced expiration in both groups. CONCLUSION: Infants with exposure to maternal smoking and infants with a family history of asthma have altered lung function, and a positive response to a bronchodilator is one variable that seems to differentiate the two groups.

Airway Resistance↗

PubMed1999

Protracted results of dose-intensive therapy using cyclophosphamide, carmustine, and continuous infusion etoposide with autologous stem cell support in patients with relapse or refractory Hodgkin's disease: a phase II study from the North American Marrow Transplant Group.

To determine the long-term results of high-dose chemotherapy and stem cell support in relapsed or primary refractory Hodgkin disease patients. One hundred and thirty-one patients with relapsed or primary refractory Hodgkin's disease were treated with a dose-intensive therapy protocol consisting of etoposide (2400 mg/m2 continuous intravenous infusion) cyclophosphamide (7200 mg/m2 intravenously), and carmustine (300-600 mg/m2 intravenously) CBVi. All patients had previously failed conventional chemoradiotherapy. Severe toxicities were related to infectious, hepatic, and pulmonary complications. Fatal, regimen-related toxicity was 19%; liver and lung dysfunction, as well as infection, were the most frequent problems. Ninety-one (69%) of the patients achieved a complete response (CR) (95% CI = 59% to 75%) after CBVi and autologous stem cell infusion. With a median follow-up of 5.1 years (range 3.0 to 9.5 years), overall and event-free survival are 44% (95% CI = 33% to 47%) and 38% (95% CI = 28% to 46%) respectively. While univariate analysis did not reveal a statistically significant variable to predict a better response, responsiveness to therapy demonstrated a trend. We conclude that CBVi is an effective therapy for relapsed or refractory Hodgkin's disease, producing long-term, durable remissions.

Adolescent↗

PubMed1999

An analysis of the late effects of radiotherapy in pediatric central nervous system tumors.

PURPOSE: The purpose of this study is to assess the long term results of all pediatric patients diagnosed with central nervous system (CNS) tumors treated with external beam radiotherapy either primarily or postoperatively. MATERIALS: Forty-seven pediatric patients with CNS tumors were treated between 1978 and 1989 with external beam radiotherapy to customized fields using cobalt 60, 4, 6, or 18 MV photons. Daily doses ranged from 1.5 to 2.0 Gray; total doses from 35 to 66 Gray. Ages ranged from one month to 18 years of age, with an average age of 8.2 years. Thirty-nine patients survived more than 12 months (range 36 to 178 months; median 62 months) and were included for analysis. Ten of 39 (25.6%) patients experienced Grade I to II complications and six patients had (15.7%) Grade III to IV complications for an overall incidence of 41%. The influence of field size, radiation dose, chemotherapy, age, and extent of surgical resection upon long-term complications were studied. CONCLUSION: Radiation therapy for pediatric CNS malignancies is associated with long-term complications. Significant long-term complications can be limited to an acceptable level of approximately 15%.

Adolescent↗

PubMed1998

Screening for hypercholesterolaemia in primary care: randomised controlled trial of postal questionnaire appraising risk of coronary heart disease.

OBJECTIVES: To validate a self administered postal questionnaire appraising risk of coronary heart disease. To determine whether use of this questionnaire increased the percentage of people at high risk of coronary heart disease and decreased the percentage of people at low risk who had their cholesterol concentration measured. DESIGN: Validation was by review of medical records and clinical assessment. The questionnaire appraising risk of coronary heart disease encouraged those meeting criteria for cholesterol measurement to have a cholesterol test and was tested in a randomised controlled trial. The intervention group was sent the risk appraisal questionnaire with a health questionnaire that determined risk of coronary heart disease without identifying the risk factors as related to coronary heart disease; the control group was sent the health questionnaire alone. SETTING: One capitation funded primary care practice in Canada with an enrolled patient population of about 12 000. SUBJECTS: Random sample of 100 participants in the intervention and control groups were included in the validation exercise. 5686 contactable patients aged 20 to 69 years who on the basis of practice records had not had a cholesterol test performed during the preceding 5 years were included in the randomised controlled trial. 2837 were in the intervention group and 2849 were in the control group. MAIN OUTCOME MEASURES: Sensitivity and specificity of assessment of risk of coronary heart disease with risk appraisal questionnaire. Rate of cholesterol testing during three months of follow up. RESULTS: Sensitivity of questionnaire appraising coronary risk was 87.5% (95% confidence interval 73.2% to 95.8%) and specificity 91.7% (81.6% to 97.2%). Of the patients without pre-existing coronary heart disease who met predefined screening criteria based on risk, 45 out of 421 in the intervention group (10.7%) and 9 out of 504 in the control group (1.8%) had a cholesterol test performed during follow up (P<0.0001). Of the patients without a history of coronary heart disease who did not meet criteria for cholesterol testing, 30 out of 1128 in the intervention group (2.7%) and 18 out of 1099 in the control group (1.6%) had a cholesterol test (P=0.175). Of the patients with pre-existing coronary heart disease, 1 out of 15 in the intervention group (6.7%) and 1 out of 23 in the control group (4.3%) were tested during follow up (P=0.851, one tailed Fisher's exact test). CONCLUSIONS: Although the questionnaire appraising coronary risk increased the percentage of people at high risk who obtained cholesterol testing, the effect was small. Most patients at risk who received the questionnaire did not respond by having a test.

Adult↗

PubMed1998

Transvaginal versus transperineal ultrasonography: a blinded comparison in the assessment of cervical length at midgestation.

OBJECTIVE: The study's objective was to determine the correlation and agreement between transperineal ultrasonography and transvaginal ultrasonography in the assessment of cervical length in gravid patients. STUDY DESIGN: After a pilot, unblinded series of transperineal and transvaginal cervical length measurements in 200 gravid patients, 206 study patients between 14 and 34 weeks' gestation with intact membranes and cervical dilatation of < or = 2 cm underwent transperineal and transvaginal cervical length assessment under a blinded, 2-sonographer protocol. The Pearson correlation coefficient, Lin concordance coefficient, and Bland-Altman plot were used. Acceptable concordance was defined as > 0.82, with an acceptable correlation of > 0.9 and an acceptable difference between the means of < 3 mm. The power of the study to detect this degree of concordance was estimated to be 95% at this sample size. RESULTS: Paired ultrasonographic measurements were obtained for all 206 study patients. Transperineal mean cervical length was 35 +/- 8.6 mm. Transvaginal mean cervical length was 35.9 +/- 8.8 mm. The Pearson correlation coefficient was 0.959, and the Lin concordance coefficient was 0.955, with a 95% confidence lower bound of 0.949. Close agreement between transperineal and transvaginal measurements was observed across the full range of cervical lengths (1-5 cm). The estimated difference between the paired means was 1 mm. The 95% tolerance interval for any given paired observation (Transperineal length - Transvaginal length) was -5.7 to +4 mm. CONCLUSIONS: Cervical length measured by transperineal ultrasonography demonstrates close correlation and agreement with transvaginal measurements. With sonographer experience and optimal technique, approximately 95% of transperineal cervical length observations can be expected to be within 5 mm of a given paired transvaginal measurement. Transperineal ultrasonography may be a preferred method of cervical length assessment for situations in which vaginal placement of instruments should be minimized.

Cervix Uteri↗

PubMed1998

Central venous catheter bloodstream infections in the neonatal intensive care unit.

PURPOSE: The goal of this study was to identify symptoms and signs related to central venous catheter (CVC) bloodstream infections (BSI) in neonatal intensive care unit (NICU) patients that would predict infection and to identify factors that might influence CVC longevity. METHODS: This was a retrospective cohort study evaluating 268 lines representing a total of 5,212 CVC days placed in 157 NICU patients over 29 months by the pediatric surgery and neonatology services at one children's hospital. Centers for Disease Control (CDC) criteria were used to determine laboratory-confirmed BSI. Data were analyzed by univariate methods and logistic regression and determined significant at the P less than .05 level. RESULTS: Sixty-five lines (24%) from 54 patients had confirmed CVC BSI. Fever (49%) and pulmonary dysfunction (30%) were the most common symptoms of CVC BSI. Erythema or purulent discharge at the insertion site was found in only 20% of cases. Staphylococcus epidermidis was the most common organism isolated. Factors that significantly decreased the incidence of CVC BSI were increasing estimated gestational age (EGA; P < .0013) attime of insertion, associated vancomycin use at the time of catheter placement (P < .0057), and fewer days of catheter use (P < .0291). There were no significant differences noted caused by line location or catheter type. CONCLUSION: Fever and pulmonary dysfunction were the most common signs of CVC BSI in neonates. Lower EGA and increased catheter duration were significantly correlated with infection. The use of vancomycin concurrent with catheter insertion was associated with a decreased incidence of CVC BSI, howeverconcerns regarding the emergence of vancomycin-resistant organisms preclude support of its use as a prophylactic agent.

Anti-Bacterial Agents↗

PubMed1998

Hemolytic disease of the fetus: a comparison of the Queenan and extended Liley methods.

OBJECTIVE: To compare the clinical utility of the Liley and Queenan methods to monitor the severity of fetal hemolytic disease. METHODS: Amniotic fluid bilirubin was measured in specimens from 73 women sensitized to red blood cell antigens. Chloroform-extracted amniotic fluid was evaluated spectrophotometrically for bilirubin content by using the change-from-expected value of the optical density at 450 nm. Values in the four Queenan zones were compared with those of the four zones of the Liley graph (middle zone subdivided). Clinical utility and accuracy of the two methods were compared. RESULTS: Treatment was based on interpretation of bilirubin values plotted on the Liley graph. Hydrops fetalis was not observed. The highest value for each patient was significantly more likely to be plotted in the highest zone using the Queenan method (23 of 73 compared with eight of 73 patients; P < .001). Overestimation of risk occurred with greater frequency when using the Queenan method (13 of 67 compared with seven of 67 patients; P = .031). Overestimation of risk by the Queenan method also was more likely at or before 28 weeks' gestation (10 of 49 compared with four of 49 patients; P = .031). In nine cases (13%), the Queenan graph and method would have prompted unnecessary or premature umbilical vein sampling that was withheld using the Liley graph. CONCLUSION: The performance of the linearly extended Liley graph was superior to that of the Queenan graph, because the Queenan method frequently overestimated risk.

Amniotic Fluid↗

PubMed1998

Selective opportunistic screening for hypercholesterolemia in primary care practice.

OBJECTIVES: To assess the performance of selective opportunistic screening in a primary care group practice. DESIGN: Cross-sectional survey of coronary heart disease risk factors and retrospective chart audit of cholesterol testing. SETTING: Capitation-funded primary care group practice in Ontario, Canada. SUBJECTS: 7785 enrolled patients between the ages of 20 and 69 years. INTERVENTION: Protocol-based selective opportunistic screening program for hypercholesterolemia of 45 months duration. MAIN OUTCOME MEASURES: Targeting (proportion of screening tests that were appropriate), coverage (proportion of those meeting screening criteria who had a screening test performed), over-screening (proportion of those not meeting screening criteria who had a screening test performed), and screening ratio (likelihood that a screening test was performed on an individual who met screening criteria rather than one who failed to meet screening criteria). RESULTS: 64.7% of patients tested met the practice criteria for screening. 37.7% of patients who met the practice screening criteria were tested and 24.9% of those not meeting practice screening criteria had a cholesterol test performed. The screening ratio was 1.52. CONCLUSION: Our findings bring into question the effectiveness of opportunistic approaches to preventive care.

Adult↗

PubMed1998

Observer differentiation of mechanical defects versus natural dental caries cavitations on monitor-displayed images with imaging plate readout.

OBJECTIVE: The purpose of this study was to compare the ability of dentists to detect mechanically created defects vs natural dental caries cavitations on the proximal surfaces of extracted teeth by means of storage phosphor imaging plate technology. STUDY DESIGN: Fifty-two extracted molar and premolar teeth were blocked into sets for bitewing radiographs through use of the DIGORA digital imaging system. Sixteen natural caries cavities and 28 artificial lesions were present in the 80 proximal surfaces included in the study. A group of 16 dentists assessed proximal lesions on unenhanced images on the monitor and 1 month later on contrast-enhanced images. A different group of 16 dentists assessed proximal lesions on contrast-enhanced images and 1 month later on unenhanced images. The Mann-Whitney U test was used to check for a reading-order effect. The Zelen test of odds ratio was used to test for homogeneity, and the Mantel-Haenszel analysis or stratified logistic regression was used for inference about the common odds ratio. Alpha was set at P < .05. RESULTS AND CONCLUSIONS: With the DIGORA system, there was little difference between the detection rates of mechanical defects and natural carious cavities with unenhanced images, but the mechanical defects were more readily detected when contrast-enhanced images were used. Cavity depth positively affected the odds of diagnosis of lesions, with deeper lesions being more readily detected than more superficial ones irrespective of whether they were natural or artificial. In comparison with findings of previous studies in which film and a charge-coupled device detector were used, the overall detection rate for natural dental caries was remarkably constant across the modalities.

Dental Caries↗

PubMed1998

A meta-analysis of mandibular intercanine width in treatment and postretention.

The meta-analysis technique of literature review was applied to a total of 26 previous studies to assess the longitudinal stability of postretention mandibular intercanine width. Weighted averages and standard deviations for the means of 1,233 subjects were compared for linear changes in intercanine transverse dimensions during treatment (T1), immediately after treatment (T2), and after removal of all retention (T3). Net change was defined as the difference between means at T3 and T1. Dimensional changes were also evaluated on the basis of patient pretreatment Angle classification, extraction, and nonextraction treatment modalities of each group. Paired two-tail t-tests were performed between T3 and T1 means on all groups at the a priori level of significance set at a < or = 0.05. Statistically significant differences were observed for the following groups: all patients; nonextraction; extraction; Class I; Class I extraction; Class II extraction; and, Class I Division 1 nonextraction. The findings of this study indicate that regardless of patient diagnostic and treatment modalities, mandibular intercanine width tends to expand during treatment on the order of one to two millimeters, and to contract postretention to approximately the original dimension. While statistically significant differences could be demonstrated within various groups, the magnitudes of the differences were not considered clinically important.

Dental Arch↗

PubMed1997

Survival of patients with congenital diaphragmatic hernia during the ECMO era: an 11-year experience.

BACKGROUND/PURPOSE: Congenital diaphragmatic hernia (CDH) is associated with significant mortality and morbidity. To evaluate the impact of extracorporeal membrane oxygenation (ECMO) on survival, a review of our experience with CDH patients was initiated. METHODS: The authors performed a retrospective nonrandomized analysis of 98 consecutive CDH patients who were ECMO candidates, and were symptomatic within the first day of life, and underwent repair between May 1985 and May 1996. The patients were divided into three groups: Group 1 (n = 38) refers to patients who were clinically stable and underwent repair before 48 hours of age and did not need ECMO rescue; Group 2 (n = 29) consists of patients who underwent repair but required ECMO rescue; and Group 3 (n = 31) refers to patients who met ECMO criteria preoperatively and required ECMO for stabilization and later underwent repair on ECMO. The Kaplan-Meier survival graph was used for survival analysis. RESULTS: During the 11-year span, the overall survival rate of all CDH patients was 72% (71 of 98). The survival rate of patients who did not require ECMO support was 92% (35 of 38), whereas patients who required ECMO after repair had a 72% (21 of 29) survival rate. These were compared with a 48% (15 of 31) survival rate for those undergoing repair on ECMO. The differences in survival among the three groups were statistically significant using the log-rank test (P = .0018). CONCLUSIONS: Survival was significantly better for infants who underwent successful repair without ECMO than those who required ECMO rescue pre- or postrepair. The overall improved survival of CDH patients to 72% compared with historical controls of 38% to 58% may be attributed to ECMO, but the requirement of ECMO before repair, as well as the presence of congenital anomalies (P < .01), prematurity (P < .01), the need for a Gore-Tex patch at repair (P < .05), prenatal diagnosis at less than 25 weeks' gestation (P < .01), and the occurrence of an intracranial hemorrhage (P < .01), decreases the chances of survival.

Extracorporeal Membrane Oxygenation↗

PubMed1997

Neurophysiologic monitoring to assure delivery of retrograde cerebral perfusion.

BACKGROUND: Patients undergoing complex aortic procedures performed with deep hypothermia and circulatory arrest have a significant risk of an adverse neurologic event when the arrest period is prolonged. Retrograde cerebral perfusion appears to improve cerebral protection, although collapsed cortical veins or functional jugular venous valves may restrict flow at the frequently recommended maximum pressure of 25 mm Hg. Therefore, the purpose of this study was to demonstrate the benefit of multimodality neurophysiologic monitoring in assuring delivery of retrograde cerebral perfusion. METHODS: Electroencephalography, cerebral blood flow velocity, and regional cerebral venous oxygen saturation were used to quantify the intraoperative neurophysiologic changes accompanying retrograde cerebral perfusion. The magnitude of changes was compared with those previously observed during arrest without retrograde cerebral perfusion. RESULTS: Thirty patients underwent complex aortic procedures necessitating circulatory arrest, 22 with retrograde cerebral perfusion. The mean retrograde perfusion pressure of 40 mm Hg (30 to 49 mm Hg, 95% confidence interval) and flow rate of 1.2 L/min (0.9 to 1.6 L/min) necessary to achieve documented retrograde cerebral perfusion was much higher than previously recommended. During both retrograde cerebral perfusion and rewarming, cerebral oximetric monitoring guided adjustments in perfusion parameters to limit the rate of desaturation to 0.4% per minute (0.3% to 0.6%). With retrograde cerebral perfusion there was a rapid (1) recovery of electroencephalographic activity during rewarming (21 minutes [range 16 to 26 minutes]) and (2) return of consciousness after the operation (81% [58% to 95%, 95% confidence interval] awake by 12 hours). There was no transcranial Doppler evidence of cerebral edema with retrograde cerebral perfusion. Two neurologic complications occurred in the 22 patients managed with retrograde cerebral perfusion and one in the eight patients managed with arrest only. CONCLUSIONS: Multimodality neurologic monitoring assured optimal brain cooling and bihemispheric delivery of retrograde cerebral perfusion. Necessary retrograde pressure and flow were often higher than values previously reported. Avoidance of profound cerebral venous oxygen desaturation during retrograde cerebral perfusion and rewarming was associated with rapid recovery of neurologic function.

Adult↗

PubMed1997

Casting the screening net: separating big fish from little fish.

Screening tests are a rapidly growing part of medical practice. If we are going to make the best use of resources, screening tests need to be considered in terms of effectiveness, efficiency and equity. We present a framework as a way to think about screening programmes. The framework expands on existing literature that recognizes two categories of screening: universal and opportunistic. By adding the dimension of 'selectivity', we identify four categories of screening: active non-selective (universal or mass screening), active selective, opportunistic non-selective and opportunistic selective. We illustrate the framework by categorizing screening recommendations for high serum cholesterol levels. We conclude there is no one ideal strategy for screening that simultaneously satisfies criteria of effectiveness, efficiency and equity. However, our framework allows a systematic consideration and balancing of these objectives in the development and assessment of screening programs. In this way, it may assist decision-makers by making this trade-off more explicit.

Canada↗