Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

734 Evaluation of A Webinar Based Surgical Teaching Course (EDUCATE) - A Prospective Cohort Study

Aim

Anecdotal evidence suggests Foundation Year (FY) doctors start surgical rotations with less confidence than medical rotations. The study aimed to determine the effect of a national webinar-based surgical teaching course on participants’ confidence, and to assess attitudes surrounding undergraduate surgical education.

Method

This prospective cohort study is reported with reference to STROBE guidelines and received ethical approval. A series of 15 free-access webinars was developed based on the Royal College of Surgeons Undergraduate Curriculum. An expert-validated questionnaire was used to collect data before and after the course. Inclusion criteria were UK-based medical students and FY doctors who attended at least one webinar. The primary outcome was confidence in completing common tasks during surgical rotations.

Results

Completed pre-course (484) and post-course (352) questionnaires yielded 92 paired samples (63% female). 85% were medical students, representing 29 UK universities, and 15% FY doctors. Mean confidence in assessing, investigating, and implementing initial management of surgical conditions was greater after the intervention (p ≤ 0.001). Mean confidence in managing on-call tasks and starting a surgical FY job was also higher post-course greater (p ≤ 0.001). These improvements correlated with webinar attendance (p ≤ 0.05). 27.1% of participants were satisfied with the quality of undergraduate surgical education. 22.9% agreed that surgical placements prepared them well to manage surgical tasks.

Conclusions

Medical students and FY doctors report low confidence and feel unprepared in managing surgical tasks. Additionally, they report poor satisfaction with undergraduate surgical education. This shortfall may be improved through delivery of a national, accessible, targeted online webinar series and curriculum.

O43 Virtual: virtual interactive surgical skills classroom: a randomized controlled trial (protocol)

Introduction

High costs and inaccessibility are significant barriers to face-to-face basic surgical skills (BSS) training. Virtual classrooms enable the combination of computer-based learning with interactive expert instruction. They may optimise resources and increase accessibility, facilitating larger-scale training with a similar educational benefit. We aim to evaluate the efficacy of virtual BSS classroom training compared to both non-interactive video and face-to-face teaching.

Method

72 medical students will be randomly assigned to three equal intervention groups based on surgical skills experience and confidence. Interventions will be implemented following an instructional video. Group A will practice independently, Group B will receive face-to-face training, and Group C will attend a virtual classroom. Participants will be recorded placing three interrupted sutures with hand tied knots pre- and post-intervention. Objective Structured Assessment of Technical Skills (OSATS) will be blind marked by two experts.

Result

Change in confidence, time to completion and a novel granular performance score will also be measured. Each intervention’s feasibility and accessibility will be assessed. Significant improvement in OSATS within groups will be indicative of intervention quality. Difference in improvement between groups will determine the relative performance of the interventions.

Conclusion

This will be the largest randomised control trial investigating virtual BSS classroom training. It will serve as a comprehensive appraisal of the suitability of virtual classrooms as an alternative to face-to-face training. The findings will assist the development and implementation of further resource-efficient training programs during the COVID-19 pandemic and beyond.

Take-home Message

This is the first RCT assessing virtual basic surgical skill classroom training and serves as a comprehensive appraisal of the suitability of virtual classrooms as an alternative to face-to-face training. The findings will assist the development and implementation of further resource-efficient training programs during the COVID-19 pandemic and in the future.

429 National Evaluation of Confidence and Preparedness for Surgical Rotations in Medical Students and Foundation Year Doctors

Introduction

Limited published and anecdotal evidence suggests foundation year (FY) doctors start their surgical rotations with lower confidence than medical rotations. This may be due to insufficient undergraduate practical teaching related to common surgical rotations. This study aimed to evaluate the confidence and preparedness for surgical rotations of medical students and FY doctors.

Method

An expert-validated questionnaire was distributed nationally to UK medical students and FY doctors. The primary outcome was confidence in completing common tasks during surgical rotations.

Results

491 participants (84% medical students, 16% FYs) were recruited from 36 UK medical schools. 80% were likely to pursue a career in surgery however only 7% felt confident about starting a surgical FY job. 66% felt neutral or unsatisfied about the quality of medical school surgical teaching, and 80% indicated that placements did not prepare them well to manage common FY surgical tasks. The internal reliability of the questionnaire was high (=0.939).

Conclusions

Medical students and FY doctors lack confidence and preparation for surgical jobs. High-quality, practically grounded educational courses such as the National Surgical Teaching Society (NSTS) webinar curriculum could improve confidence and preparedness for surgical rotations. Further research evaluating the benefits of such courses is warranted.

Model reduction techniques for the computation of extended Markov parameterizations for generalized Langevin equations

The generalized Langevin equation is a model for the motion of coarse-grained particles where dissipative forces are represented by a memory term. The numerical realization of such a model requires the implementation of a stochastic delay-differential equation and the estimation of a corresponding memory kernel. Here we develop a new approach for computing a data-driven Markov model for the motion of the particles, given equidistant samples of their velocity autocorrelation function. Our method bypasses the determination of the underlying memory kernel by representing it via up to about twenty auxiliary variables. The algorithm is based on a sophisticated variant of the Prony method for exponential interpolation and employs the positive real lemma from model reduction theory to extract the associated Markov model. We demonstrate the potential of this approach for the test case of anomalous diffusion, where data are given analytically, and then apply our method to velocity autocorrelation data of molecular dynamics simulations of a colloid in a Lennard-Jones fluid. In both cases, the velocity autocorrelation function and the memory kernel can be reproduced very accurately. Moreover, we show that the algorithm can also handle input data with large statistical noise. We anticipate that it will be a very useful tool in future studies that involve dynamic coarse-graining of complex soft matter systems.

Treatment Patterns and Clinical Outcomes in Advanced Lung Neuroendocrine Tumors in Real-World Settings: A Multicenter Retrospective Chart Review Study

BACKGROUND

Using data from four tertiary referral centers in the U.S., we assessed real-world treatment patterns and clinical outcomes of patients with advanced lung neuroendocrine tumors (NETs).

SUBJECTS, MATERIALS, AND METHODS

We performed a retrospective chart review of adult patients with locally advanced/metastatic (typical/atypical) lung NETs treated between July 2011 and December 2014. Index date was histologically confirmed typical/atypical carcinoid tumor diagnosis date. Data included baseline characteristics, treatment patterns, progression, death, and lung NET-related health care resource use from index date through last contact/death. Time to treatment discontinuation and first progression, time from first to second progression, and overall survival (OS) were estimated using Kaplan-Meier analysis.

RESULTS

We identified 83 patients; 19 (23%) had functional NET. First-line treatments included somatostatin analogs (SSAs) alone (56%) or in combination with other therapies (6%), cytotoxic chemotherapy (20%), external beam radiation therapy (EBRT) (9%), liver-directed therapy (LDT) (4%), and everolimus/other (5%). Sixty patients had second-line therapy including SSA alone (18%) or in combination (40%), cytotoxic chemotherapy (17%), everolimus (12%), LDT (7%), EBRT (3%), and other treatments (3%). Median time (months) to first-line discontinuation were as follows: SSAs, 43.3; cytotoxic chemotherapy, 3.6. Overall median time (months) to investigator-assessed progression following treatment initiation was 12.4. Median OS (months) following treatment initiation was 66.4 for all patients and 81.5 for patients receiving SSAs.

CONCLUSION

SSAs, alone and in combination, are common treatments for advanced lung NETs. Patients have additional treatment options and relatively long survival compared with patients with other advanced cancers. Treatment pattern assessment following approval of newer treatments is needed.

IMPLICATIONS FOR PRACTICE

Somatostatin analogs (SSAs), cytotoxic chemotherapy, EBRT, liver-directed therapy, and targeted therapies are common treatments for locally advanced/metastatic (typical/atypical) lung neuroendocrine tumors (NETs). SSAs alone or in combination with other treatment modalities were the most common first- and second-line therapy, followed by cytotoxic chemotherapy. Patients continued treatment with SSAs long-term with median treatment duration of 43 months. Median overall survival was 66 months following initiation of first-line therapy for all patients. Treatment pattern assessment beyond the time period of this study is needed given recent U.S. Food and Drug Administration approvals for additional treatments for lung NETs that will likely be incorporated in the treatment landscape.

Mild traumatic brain injury in the United States: demographics, brain imaging procedures, health-care utilization and costs

Objective: To characterize mild traumatic brain injury (mTBI) patients in the USA, describing location of diagnosis, timing, and modality of imaging procedures, health-care resource utilization (HRU) and costs in the 12-month period post-diagnosis. Research Design: Retrospective claims analysis Methods: Anonymized data from the OptumHealth Care Solutions claims database (2006-2016). The index date was the first date with an mTBI diagnosis. HRU and costs (2016 USD) were assessed in the 12-month post-index period. Results: A total of 80,004 patients with mTBI were included: 60% were under 26 years and 54% were male. Mild TBI was most frequently diagnosed in an emergency department (ED) for all age groups, except patients aged 11-17 years, for whom the outpatient setting was the most frequent place of diagnosis. Almost half (47%) received brain imaging on the index date, with 98% of which receiving computed tomography. Mean follow-up health-care costs were $13,564 (SD = $41,071), primarily from inpatient ($4,675, SD = $29,982) and non-ED outpatient/physician office visits ($4,207, SD = $12,697). Older patients had greater HRU and higher health-care costs. Conclusions: The findings of this claims-based study show substantial HRU and costs associated with mTBI diagnosis during a 12-month follow-up period.

Presence of Autoantibodies in the Sera of Meniere's Disease

We examined the sera of patients with Meniere's disease for the presence of antibodies against 8 inner ear antigens by enzyme-linked immunosorbent assay (ELISA). One hundred eight patients with Meniere's disease and 28 control subjects were studied. The antibodies against chicken type II collagen, bovine type II collagen, the cyanogen bromide cleaved peptide 11 (CB11) of each, type IX and XI collagens, C-Raf, and tubulin were measured by ELISA. The sensitivity of each antigen was between 37% and 60% individually, and was 91% when all 8 inner ear antigens were combined. These results showed that 91% of Meniere's disease sera have antibody activities to 1 or more of these inner ear antigens. The results suggest that performing ELISA for these 8 inner ear antigens was useful as a diagnostic tool for Meniere's disease. Further study is required for elucidating the role of these antigens in the pathogenesis of Meniere's disease, which might eventually result in better therapy.

Seasonal Activity, Density, and Collection Efficiency of the Blacklegged Tick (Ixodes scapularis) (Acari: Ixodidae) in Mid-Western Pennsylvania

Although Pennsylvania has recently reported the greatest number of Lyme disease cases in the United States, with the largest increase for PA occurring in its western region, the population biology of the blacklegged tick (Ixodes scapularis Say) has not been adequately characterized in western PA. We studied the seasonal activity of host-seeking I. scapularis larvae, nymphs, and adults in mid-western PA over the course of a year, including a severe winter, and determined their absolute densities and collection efficiencies using replicated mark-release-recapture or removal methods. Our results are compared to those from similar studies conducted in the highly Lyme disease endemic Hudson Valley region of southeastern New York State. The seasonal activity of I. scapularis was intermediate between patterns observed in the coastal northeastern and upper Midwestern United States. Only one peak of larval activity was observed, which was later than the major peak in the Midwest, but earlier than in the northeast. Seasonal synchrony of larvae and nymphs was similar to the northeast, but the activity peaks were much closer together, although not completely overlapping as in the Midwest. Pre- and postwinter relative densities of questing adult I. scapularis were not significantly different from one another. The absolute densities and collection efficiencies of larvae, nymphs, and adults were comparable to results from classic research conducted at the Louis Calder Center in Westchester County, NY. We conclude that the population biology of I. scapularis in mid-western PA is similar to southeastern NYS contributing to a high acarological Lyme disease risk.

Development and evaluation of a standardized questionnaire for identifying adverse events in vaccine clinical trials

In vaccine trials, diary questionnaires or vaccination report cards (VRCs) are used extensively to collect complaints reported by subjects or guardians following vaccination. These have not been evaluated for accuracy or standardized to facilitate tolerability comparisons among vaccines.Objectives -(1) Develop standardized, age-specific VRCs for collecting self-reported adverse events (AEs) in trials; (2) Evaluate whether complaints elicited by nurse examinations or telephone interviews were missed by VRCs.Methods -Vaccine-trial databases, focus groups, experts and experienced nurses were used to develop paediatric and adolescent/adult VRCs. VRCs were evaluated at four sites. The primary outcome was subjects with AEs missed on the VRC and reported in nurse examinations (for injection-site reactions) or telephone interviews (for systemic complaints).Results -Of 855 subjects, 96.5% completed VRCs. For systemic complaints, 1.5% (12/812) reported both no complaint on VRCs and at least one complaint in telephone interviews. For injection-site reactions, 5.1% (53/1030) of injection sites had both no reaction reported on VRCs and had reactions noted by nurse examination. No missed AEs were rated as severe.Conclusion -The data suggest VRCs provide a practical and reasonably complete method of eliciting complaints following vaccination. Copyright (c) 2000 John Wiley & Sons, Ltd.

HIV care need not hamper maternity care: a descriptive analysis of integration of services in rural Malawi

OBJECTIVE

To evaluate the use of reproductive health care and incidence of paediatric HIV infection during the expansion of antiretroviral therapy and services for the prevention of mother-to-child transmission in rural Malawi, and the influence of integration of these HIV-related services into general health services.

DESIGN

Descriptive analysis.

SETTING

Thyolo District, with a population of 600,000, an HIV prevalence of 21% and a total fertility rate of 5.7 in 2004.

POPULATION

Women attending reproductive health services care in 2005 and 2010.

METHODS

Review of facility records and databases for routine monitoring.

MAIN OUTCOME MEASURES

Use of antenatal, intrapartum, postpartum, family planning and sexually transmitted infection services; incidence of HIV infection in infants born to mothers who received prevention of mother-to-child transmission care.

RESULTS

There was a marked increase in the uptake of perinatal care: pregnant women in 2010 were 50% more likely to attend at least one antenatal visit (RR 1.50, 95% CI 1.48-1.51); were twice as likely to deliver at a healthcare facility (RR 2.05, 95% CI 2.01-2.08); and were more than four times as likely to present for postpartum care (RR 4.40, 95% CI 4.25-4.55). Family planning consultations increased by 40% and the number of women receiving treatment for sexually transmitted infections doubled. Between 2007 and 2010, the number of HIV-exposed infants who underwent testing for HIV went up from 421 to 1599/year, and the proportion testing positive decreased from 13.3 to 5.0%; infants were 62% less likely to test HIV positive (RR 0.38, 95% CI 0.27-0.52).

CONCLUSIONS

During the expansion and integration of HIV care, the use of reproductive health services increased and the outcomes of infants born to HIV-infected mothers improved. HIV care may be successfully integrated into broader reproductive health services.

A quantitative analysis of variability in brachial plexus anatomy

The aim of this study was to quantify the lengths of nerve segments within the brachial plexus. Twenty cadavers were dissected bilaterally, giving a total of 40 brachial plexuses for measurement. Individual lengths of plexus segments were measured and recorded, and means and standard deviations were calculated for all data. Differences between the means were statistically evaluated using the Student's t-test. Only 3 of 16 segments were found to be longer in women on average, which included the anterior division of the superior trunk, the anterior division of the middle trunk and the posterior division of the inferior trunk. All three cords (medial, lateral, and posterior) were found to be significantly different between genders, the longer segments being in males. Significant bilateral differences were also observed when right and left brachial plexuses from each cadaver were compared. Extra lateral heads (ELHs) to the median nerve were found in 50% of brachial plexuses, the anatomy of which varied bilaterally as well as between genders. Awareness of this variability is important both to anatomists and to clinicians who operate on and around the brachial plexus.

Increased mortality of elderly female peritoneal dialysis patients with diabetes--a descriptive analysis

Three recent studies using registry data from the United States, in comparing the mortality risks between peritoneal dialysis (PD) and hemodialysis (HD), have consistently found that elderly diabetic women on PD have a higher mortality risk as compared with their counterparts on HD. Though the cause for this observation is not clear, the phenomenon may be unique to the United States. Alternatively, a selection bias impossible to decipher may be at work in these studies, as none of them have data on comorbidity, nutrition, or adequacy of dialysis. Finally, the possibility that elderly diabetic women are, for some reason, more vulnerable to the ill effects of peritoneal dialysis should be considered. We report here a retrospective analysis of 47 diabetic women, above 55 years of age, with end-stage renal disease, who were started on PD and who later died on dialysis. The primary outcome of interest was cause of death. Demographic details about the patients, comorbid conditions, dialysis adequacy, and biochemical parameters at the start of PD were noted. Death in these patients was attributed mainly to vascular causes, and there appeared to be a high prevalence of peripheral vascular disease. Infection was the next major cause of death, being the primary cause in 14 patients. Of these, only 5 patients had peritonitis. On a Cox regression analysis, only patient age and duration of diabetes at onset of dialysis were found to be predictive of vascular death. No factor was found to be predictive of death from infection. It appears that elderly diabetic women on PD die mainly of the long-term complications of diabetes.

Late renal transplant failure: an adverse prognostic factor at initiation of peritoneal dialysis

BACKGROUND

Early renal transplant failure necessitating a return to dialysis has been shown to be a poor prognostic factor for survival. Little is known about the outcome of patients with late transplant failure returning to dialysis. It was our clinical impression that late transplant failure (>2 months) carries an increased morbidity and mortality risk in patients returning to dialysis.

OBJECTIVE

To determine whether patients with a failed renal transplant have an outcome different to those on dialysis who have never received a kidney transplant.

SETTING

Peritoneal dialysis (PD) unit in a teaching hospital.

PATIENTS AND DESIGN

All failed renal transplant patients (fTx) in the Toronto Hospital Peritoneal Dialysis program between 1989 and 1996 were identified. This cohort of 42 fTx patients was compared with a cohort of randomly selected never-transplanted PD patients (non-Tx). The PD program was selected because of the availability of well-documented patient archival material. The non-Tx group was matched for age and presence of diabetes. Data were collected until retransplantation, change of dialysis modality or center, death, or until June 1998.

RESULTS

There was no difference at initiation of PD between groups in serum albumin, residual renal function, or mean serum parathyroid hormone level. The mean low-density lipoprotein level was significantly higher in the fTx cohort. The duration of dialysis before Tx in fTx patients accounted for the increased total length of dialysis in fTx (mean 15 months). However, post-Tx the duration of PD was similar for both groups (30.7 months for fTx vs 31.6 months for non-Tx). The fTx group had a considerably worse outcome than the non-Tx group. The time to first peritonitis, subsequent episodes of peritonitis, catheter change, or transfer to hemodialysis occurred at a much faster rate in fTx patients. The most dramatic difference was in survival. There were 3 deaths in the non-Tx group and 12 in the fTx group (p < 0.01). The mean age at time of death in the fTx group was 47.5 years. Deaths were due mainly to gram-negative peritonitis and cardiovascular disease.

CONCLUSIONS

We conclude that late failed renal transplant patients starting dialysis are at increased risk of complications and have strikingly higher mortality rates than non-Tx patients. A previously failed kidney transplant can be considered an adverse prognostic factor for patients commencing PD; these patients need to be closely monitored. Although this study was limited to PD patients, the same principles likely apply to fTx patients returning to any form of renal replacement therapy.

Charged-particle multiplicity near midrapidity in central Au+Au collisions at sqrt[SNN]=56 and 130 GeV

We present the first measurement of pseudorapidity densities of primary charged particles near midrapidity in Au+Au collisions at sqrt[s(NN)] = 56 and 130 GeV. For the most central collisions, we find the charged-particle pseudorapidity density to be dN/deta|(|eta|<1) = 408+/-12(stat)+/-30(syst) at 56 GeV and 555+/-12(stat)+/-35(syst) at 130 GeV, values that are higher than any previously observed in nuclear collisions. Compared to proton-antiproton collisions, our data show an increase in the pseudorapidity density per participant by more than 40% at the higher energy.

Photoelastic analysis of stresses produced by different acetabular cups

Porous-coated acetabular components can provide long-term biologic fixation to bone. However, the periacetabular stress patterns and mechanisms by which different types of cementless acetabular cups obtain initial stability is not clear. In the current study, periacetabular stresses produced by different cementless acetabular cup geometries were quantitated using a three-dimensional photoelastic model. The cup geometries consisted of trispiked, finned, hemispherical, and nonhemispherical (wider than a hemisphere at the periphery) geometries. The cup models were loaded incrementally in the photoelastic material to simulate periacetabular stress distributions at the time of implantation during surgery rather than under physiologic weightbearing loads. The peripheral stress distributions and their magnitudes induced by the trispiked and oversized hemispherical cups were similar, but the trispiked cup induced localized high stress regions where the spikes penetrate the bone model. The fins separated the periacetabular material into quadrants, which was associated with decreased peripheral stresses. A nonhemispherical geometry with a wider diameter at the rim than a hemisphere increased peripheral stresses more than an oversized hemispherical geometry and required less force to seat the implant. Although various cementless acetabular cups can perform well clinically, they produce different periacetabular stresses and appear to obtain initial fixation by different mechanisms.

Evaluation of Salmonella typhimurium mutants in a model of experimental gastroenteritis

Salmonella typhimurium strains harboring independent, defined mutations in aroA, invA, ssrA, or msbB were assessed for their ability to induce fluid accumulation, tissue damage, and local inflammation in rabbit ileal loops. Three wild-type strains of S. typhimurium, TML, HWSH, and SL1344, and two mutant strains, S. typhimurium SL1344 ssrA and S. typhimurium SL1344 msbB, consistently induced fluid accumulation in the lumen of loops and inflammation of loop-associated tissues. In contrast, three different S. typhimurium aroA strains and an invA mutant of SL1344 did not induce significant fluid accumulation in the rabbit ileal loops. However, the S. typhimurium aroA strains did induce an inflammatory infiltrate and some local villus-associated damage, but the invA mutant did not. Histologically, wild-type S. typhimurium, S. typhimurium SL1344 ssrA, and S. typhimurium SL1344 msbB demonstrated more severe effects on villus architecture than S. typhimurium aroA strains, whereas S. typhimurium invA-infected loops showed no detectable damage. This suggests that villus damage most likely contributes to fluid accumulation within the loop.

How preliminary data affect people's stated willingness to enter a hypothetical randomized controlled trial

PURPOSE

To explore how preliminary trial data affect the general public's stated willingness to enter a randomized clinical trial.

METHODS

We asked 165 prospective jurors to imagine that their physicians wanted them to enroll in a clinical trial. We then presented them with scenarios portraying preliminary trial results--for example, 9 out of 10 patients get better with drug A and 5 out of 10 get better with drug B--and asked after each scenario, whether they would choose to be part of the trial. We designed the scenarios to test how stated willingness to enter the trial would be influenced by: 1) the difference in effectiveness of the 2 treatments based on the patients enrolled thus far; and 2) by the chance that the difference in effectiveness was random (i.e., the P value). The subjects' willingness to enter the trial at various decision points was analyzed using logistic regression.

RESULTS

Fewer subjects were willing to enter the trial as preliminary data indicated either an increasing difference in the effectiveness of the two treatments or an increasing statistical significance of that difference. For example 75% of subjects were willing to enter the research trial before any preliminary data were presented, but this number fell to 49% when subjects were presented with preliminary data showing that 9 out of 10 patients improved with one treatment and 5 out of 10 with the other. Multivariable logistic regression revealed that higher P values (odds ratio = 4.29; P < 0.001; 95% CI: 2.22-8.28) and smaller differences in effectiveness (odds ratio = 0.02; P < 0.001; 95% CI: 0.00-0.07) implicit in preliminary data presented to subjects made subjects less likely to agree to enter clinical trials. After adjustment for other relevant variables, male gender was associated with increased willingness to enter the trial.

CONCLUSION

A subjects' willingness to enter the hypothetical trial was influenced by preliminary data. Fewer subjects were willing to enter the trial as the differences in benefit between 2 treatment groups increased. However, the majority of subjects were willing to enter the hypothetical trial even when preliminary evidence strongly favored one treatment over another. Given the importance of informed consent in entering patients in clinical trials, these results should be confirmed in actual trial settings.

Effect of cementless acetabular cup geometry on strain distribution and press-fit stability

Use of cementless acetabular cups, which are slightly larger than the reamed acetabulum, can provide press-fit stability without screws; however, the ideal cup geometry to maximize stability is not clear. Acetabular strain distribution, deformation, and implant stability were studied using an axisymmetric finite-element model, and mechanical stability was assessed by testing lever-out and extraction forces required to displace different cup geometries from foam bones. The implants tested included four nonhemispheric cup geometries and 1- and 2-mm oversized hemispheric geometries. A nonhemispheric cup that provides a gradual transition from a hemisphere at the dome to a larger peripheral dimension appears to maximize peripheral strains and implant stability without increasing overall acetabular deformation as much as a larger oversized hemispheric cup.

Endoscopic closure of postsurgical anterior cranial fossa cerebrospinal fluid leaks

OBJECTIVE

The primary objective of this study is to present an alternative technique to closure of anterior cranial fossa cerebrospinal fluid (CSF) leaks. This study also serves to review our experience with our technique and presents some technical "tricks" we have learned through experience.

METHODS

The design of this study is a clinical chart review. The setting is an academic medical center.

RESULTS

Eight patients were referred for closure of postsurgical CSF leaks. Seven of eight patients underwent closure with one attempt and closure was achieved after a second attempt in one patient. Follow-up ranged from 1.5 to 4.0 years. There were no complications. No patient developed an acute or delayed episode of meningitis.

CONCLUSION

The technique of endoscopic closure of a CSF leak is a safe and effective means for closure of a postsurgical anterior cranial fossa CSF fistula when performed by an experienced operator.

A prospective randomized study comparing short- and intermediate-term perioperative outcome variables after spinal or general anesthesia for lumbar disk and laminectomy surgery

General or regional anesthesia may be used for lumbar laminectomy. To determine whether one method is superior, 122 patients were randomly assigned to receive either a standard general anesthetic (GA) or spinal anesthesia (SA) supplemented with intravenous (IV) propofol sedation. Data from the intraoperative period through hospital discharge were collected and compared. Demographically, both groups were similar. Total anesthesia (131.0 +/- 4.3 vs 106.6 +/- 3.2 min) and surgical times (81.5 +/- 3.6 vs 67.1 +/- 2.8 min) were longer in the GA group. Intraoperative hemodynamics were similar between groups except that the incidence of increased blood pressure was more frequent with GA (26.2% vs 3.3%). Blood loss was less during SA (133 +/- 18 mL vs 221 +/- 32 mL). Postanesthesia care unit (PACU) heart rates and mean arterial pressures were higher in the GA group. Peak pain scores in the PACU were higher after GA compared with SA (58 +/- 4 vs 22 +/- 3) as were the number of patients who required analgesics. Severe nausea was more common in the GA group both in the PACU and during the 24 h after surgery. Analgesic requirements after discharge from the PACU, urinary retention, and days in the hospital did not differ between groups. This study suggests that SA may be superior to GA both intraoperatively and postoperatively for lumbar spine procedures lasting less than 2 h.

SF-20 score and item distributions in a human immunodeficiency virus-seropositive sample

The question of whether the full range of possible health states is measured by the Medical Outcomes Study (MOS) 20-Item Short-Form Health Survey (SF-20) in human immunodeficiency virus (HIV)-seropositive individuals is examined in this article. Ninety-five HIV-seropositive men (37 with asymptomatic infection, 58 with symptomatic infection) from two primary care practices were enrolled. Patients completed the SF-20 evaluating six dimensions of health status. Asymptomatic patients reveal substantial skew in score distributions for the dimensions of physical (-1.60), role (-1.19), and social (-1.13) functioning; no substantial skew is exhibited by symptomatic patients. Both subgroups reveal ceiling effects for physical, role, and social functioning, and pain dimensions; asymptomatic patients' ceiling effects are higher (physical functioning: 65% versus 31%; role functioning: 73% versus 41%; social functioning: 54% versus 43%; and pain: 41% versus 24%). Patients from both subgroups reveal floor effects for the role functioning dimension (asymptomatic patients, 22%; symptomatic patients, 34%). When looking at items rather than scales, asymptomatic patients' item distributions for the physical, role, and social functioning, and pain dimensions reveal clustering toward positive health states in most items; distributions of symptomatic patients are similar. Because this HIV-seropositive sample exhibits substantial ceiling effects in four of six SF-20 dimensions, effects that particularly are notable for asymptomatic patients, these dimensions should be revised for use in HIV-seropositive individuals or a disease-specific quality of life instrument should be constructed.

The effects of high and low BACs on the Hoffmann reflex

The purpose of this study was to measure and assess the magnitude and latency of the H-reflex and M-response between pre- and post-alcohol consumption. Also of interest was the comparison of the H-reflex and M-response between the rising and falling curves of BAC. Seven male volunteer subjects participated in this study. Testing started with pre-alcohol BAC and EMG recordings from the tibial nerve following an electrical stimulation. After alcohol consumption, BAC readings were obtained every five minutes, and the EMGs were recorded at the following BAC levels (in mg/dl): 75, 100, and falling 75. H-latency, H-amplitude, and M-response were identified within the EMG signals. The analysis focused on the comparisons of these measures between each of the BAC levels and the baseline, as well as between the rising and falling BACs. Results showed that, overall, the H-reflex and M-response were depressed following alcohol consumption. In addition, the depression of H-reflex appeared to be greater during the rising curve than the falling curve.

Family communication and teenagers' contraceptive use

Improving communication about sex and birth control between parents and their children has often been cited as a means to encourage young people to use contraceptives more effectively. In an attempt to test this hypothesis, we interviewed 290 adolescents at family planning clinics in southeastern Pennsylvania three times in the course of 15 months about their communication with their families and their use of contraceptives. At the time of their first clinic visit, two-fifths of the teenagers said that their mothers knew that they had gone to the clinic; this proportion rose to almost three-fifths six months later and to about three-quarters at the end of 15 months. However, the proportion of teenagers who said that they had discussed sex or birth control with their mothers remained almost the same; the proportion who said that they would never discuss such topics with their mothers also remained fairly constant. The teenagers whose mothers knew of their clinic attendance at the time of their first visit were no more likely to have had extensive conversations with their mothers about sex or contraception than were the teenagers whose mothers found out afterwards. Among a subsample of the mothers of these young women, fewer than one-third said that they had ever discussed their daughters' sexual activity with them. There was only a modest level of correspondence between the mothers' responses and their daughters' replies; for the most part, the mothers thought that they were much more communicative about sex and birth control than their daughters perceived them to be.(ABSTRACT TRUNCATED AT 250 WORDS)

Contraceptive continuation among adolescents attending family planning clinics

An attempt to find a reliable way to measure contraceptive continuation among teenagers was made in a study of 445 adolescents under age 18 who made an initial visit to one of nine federally funded family planning clinics in the Philadelphia area in 1980 and 1981. The participants were interviewed at their initial visit and at six and 15 months to collect information on background characteristics, pregnancy history and contraceptive use. A cross-check of the information on contraceptive use reported during the study showed that 38 percent of the respondents who reported that they had been continuous users during the 15 months supplied information at other points indicating that they had not always used contraceptives during that period. In an attempt to examine the effects of adolescent reporting errors on measures of contraceptive use, the investigators constructed three alternative measures of contraceptive continuation. The simplest measure assessed current use at 15 months. A second measure accepted only reports of continuous use at 15 months and ignored inconsistent data. The third measure corrected for inconsistent data. Applying these measures to the study population produced proportions of contraceptive continuation ranging from a low of 43 percent when the most stringent measure was used to a high of 82 percent for the current-use category. Whatever the measure used, much of the discontinuation appears to have occurred in the first three months after the initial visit to a family planning clinic.(ABSTRACT TRUNCATED AT 250 WORDS)

The size of the mastoid air cell system among black and white children with middle ear effusion

The incidence of middle ear disease among black American children is lower than among white children. Many factors may contribute to this difference. The possibility of an anatomical variation regarding the cellularity of the mastoid process was investigated. The size of the mastoid air cell system was measured in black and white children with and without middle ear effusion. A significantly smaller mastoid air cell system was found in the groups with middle ear disease compared to those without disease. No difference between white and black children in diseased as well as non-diseased ears could be demonstrated.

Physical attractiveness and personality development

A test of the relationship between physical attractiveness and ego development was completed through an interview study of 294 men and women college students. Ss responded to personality measures assessing identity formation, locus of control, and ego functioning and were rated on facial attractiveness and body form scales. Contrary to the physical attractiveness stereotype, attractive and unattractive Ss did not differ in their personality styles.