Development and Validation of a Hybrid Bronchoscopy Trainer Using Three-Dimensional Printing

INTRODUCTION

Simulation is an essential component of medical education. Commercially available intubation simulators often lack anatomical fidelity of the lower airway and are therefore not suitable for teaching bronchoscopy or lung isolation. By using a desktop 3-dimensional (3D) printer, we aimed to create and validate a hybrid simulator from an existing mannequin with a 3D-printed lower airway that has anatomical fidelity and is financially affordable compared with commercially available models.

METHODS

Using an anonymized computed tomography scan of an adult male patient, we developed a 3D model of the airway from below the larynx to the 3rd generation bronchi, which was then printed on a desktop 3D printer. The printed airway was attached to an existing mannequin below the larynx via a universal adaptor. Ten anesthesiology attendings performed a blinded comparison of the hybrid mannequin with a commercially available mannequin for tactile and visual fidelity when performing intubation, bronchoscopy, and lung isolation. They were also asked to assess the models for educational suitability.

RESULTS

The 3D printed model was judged more suitable for teaching double-lumen tube insertion to novice physicians compared with the commercial model, with median (interquartile range) scores of 5 (4-5) versus 3 (2-4), P = 0.017. Similar results were found for bronchial blocker insertion and bronchoscopy. The visual fidelity of the bronchial anatomy was scored as 5 (4-5) and 2 (1-3) for the 3D-printed and the commercial models, respectively ( P = 0.007).

CONCLUSION

By creating a hybrid model combining an existing commercially available mannequin with a 3D-printed trachea and bronchial tree, we have created an affordable training simulator suitable for teaching lung isolation and bronchoscopy. Enhancing existing mannequins with 3D-printed parts may be of particular interest to institutions that do not have the funds to buy models with anatomical fidelity but do have access to a 3D printer.

Virtual reality and 3D printing in clinical anesthesia: a case series of two years' experience in a single tertiary medical centre

PURPOSE

Anatomically correct patient-specific models made from medical imaging can be printed on a three-dimensional (3D) printer or turned into a virtual reality (VR) program. Until recently, use in anesthesia has been limited. In 2019, the anesthesia department at Tel Aviv Medical Center launched a 3D program with the aim of using 3D modelling to assist in preoperative anesthesia planning.

METHODS

A retrospective review of all relevant patients between July 2019 and June 2021 referred for preoperative airway planning with 3D modelling. Patient files were reviewed for correlation between the model-based airway plan and the actual airway plan, the type of model used, and any anesthetic complications related to airway management.

RESULTS

Twenty patients were referred for 3D modelling. Of these, 15 models were printed, including 12 children requiring one lung ventilation. Five patients had VR reconstructions, including three with mediastinal masses. One patient had both a 3D-printed model and a VR reconstruction. There were two cases (10%) where the model plan did not correlate with the final airway plan and one case where a model could not be created because of poor underlying imaging. For the remaining 17 cases, the plan devised on the model matched the final airway plan. There were no anesthetic complications.

CONCLUSIONS

Three-dimensional modelling and subsequent printing or VR reconstruction are feasible in clinical anesthesia. Its routine use for patients with challenging airway anatomy correlated well with the final clinical outcome in most cases. High-quality imaging is essential.

In-hospital production of 3D-printed casts for non-displaced wrist and hand fractures

Objectives: To examine the clinical feasibility and results of a multidisciplinary workflow, employing rapid three-dimensional (3D) scanning and modeling software along with a high-speed printer, for in-hospital production of patient-specific 3D-printed casts, for the treatment of non-displaced wrist and hand fractures. Methods: Consenting adult patients admitted to the emergency department (ED) due to wrist or hand fractures between January and February 2021 were prospectively enrolled. The study participants underwent conversion of the standard plaster of Paris cast to a 3D-printed cast one week after the ED visit, and follow-up examinations were performed around two, six, and twelve weeks later. The primary objective was to examine the clinical feasibility in terms of complexity and length of the overall procedure. Secondary outcomes were patient-reported impressions and radiological results. Results: Twenty patients (16 males, mean age 37 ± 13.1 years) were included. The entire printing workflow took a mean of 161 ± 8 min. All patients demonstrated clinical improvement and fracture union at final follow-up, with no pressure sores or loss of reduction. Patient-reported comfort and satisfaction rates were excellent. The mean Visual Analog Scale was 0.9 ± 1.1 and 0.6 ± 1, and the mean Disabilities of the Arm, Shoulder, and Hand score was 18.7 ± 9.5 and 7.6 ± 7.6 at 2 and 6 weeks after application of the 3D-printed cast, respectively. Conclusion: The in-hospital workflow was feasible and efficient, with excellent clinical and radiographic results and high patient satisfaction and comfort rates. Our medical center now routinely provides this cast option for non-displaced wrist and hand fractures.

Level of evidence: IV, Therapeutic Study

3D-printed Cutting Guides for Lower Limb Deformity Correction in the Young Population

BACKGROUND

Three-dimensional (3D) virtual surgical planning technology has advanced applications in the correction of deformities of long bones by enabling the production of 3D stereolithographic models, patient-specific instruments and surgical-guiding templates. Herein, we describe the implementation of this technology in young patients who required a corrective osteotomy for a complex 3-plane (oblique plane) lower-limb deformity.

PATIENTS AND METHODS

A total of 17 patients (9 males, average age 14.7 y) participated in this retrospective study. As part of preoperative planning, the patients' computerized tomographic images were imported into a post-processing software, and virtual 3D models were created by a segmentation process. Femoral and tibial models and cutting guides with locking points were designed according to the deformity correction plan. They were used for both planning and as intraoperative guides. Clinical parameters, such as blood loss and operative time were compared with a traditional surgical approach group.

RESULTS

All osteotomies in the 3D group were executed with the use intraoperative customized cutting guides which matched the preoperative planning simulation and allowed easy fixation with prechosen plates. Surgical time was 101±6.2 minutes for the 3D group and 126.4±16.1 minutes for the control group. The respective intraoperative hemoglobin blood loss was 2.1±0.2 and 2.5+0.3 g/dL.Clinical and radiographic follow-up findings showed highly satisfactory alignment of the treated extremities in all 3D intervention cases, with an average time-to-bone union (excluding 2 neurofibromatosis 1 patients) of 10.3 weeks (range 6 to 20 wk).

CONCLUSION

The use of 3D-printed models and patient-specific cutting guides with locking points improves the clinical outcomes of osteotomies in young patients with complex bone deformities of the lower limbs.

LEVEL OF EVIDENCE

Level III.

In situ cryoablation of sacral Giant Cell Tumor using three-dimensional (3D) model: A case report

Three-dimensional planning of in-situ (trans-sacral) image guided cryoablation provides a method to treat sacral GCTs that accommodates the intricacies of the pelvis offering a safer, more efficacious alternative. Here we report on IM a 23-year-old female with a sacral GCT. She presented to Tel Aviv Medical Center with ongoing pain as well as neurological symptoms. For six years, the patient was in-and-out of the hospital for Denosumab treatment and recurrent infections. Eventually, further treatment became necessary, and she was treated with image guided cryoablation. By six months follow-up, the patient was mobile and pain-free.

Three dimensional printed models of the airway for preoperative planning of open Laryngotracheal surgery in children: Surgeon's perception of utility

BACKGROUND

Preoperative planning of open laryngotracheal surgery is important for achieving good results. This study examines the surgeon's perception of the importance of using life size 3D printed models of the pediatric airway on surgical decision making.

METHODS

Life-size three-dimensional models of the upper airway were created based on CT images of children scheduled for laryngotracheal-reconstruction and cricotracheal resection with anastomosis. Five pediatric airway surgeons evaluated the three-dimensional models for determining the surgical approach, incision location and length, graft length, and need for single or double-stage surgery of seven children (median age 4.4 years, M:F ratio 4:3). They rated the importance of the three-dimensional model findings compared to the direct laryngoscopy videos and CT findings for each domain on a validated Likert scale of 1-5.

RESULTS

The mean rating for all domains was 3.6 ± 0.63 ("moderately important" to "very important"), and the median rating was 4 ("very important"). There was full agreement between raters for length of incision and length of graft. The between-rater agreement was 0.608 ("good") for surgical approach, 0.585 ("moderate") for incision location, and 0.429 ("moderate") for need for single- or two-stage surgery.

CONCLUSION

Patient-specific three-dimensional printed models of children's upper airways were scored by pediatric airway surgeons as being moderately to very important for preoperative planning of open laryngotracheal surgery. Large-scale, objective outcome studies are warranted to establish the reliability and efficiency of these models.

1169 Innovative Exposure to Sleep Medicine for Medical Students

Introduction

Lack of exposure to the field of Sleep Medicine at the medical student level hinders sleep training. Instead of the traditional didactic style, there is a need for innovative collaborative measures to spark interest in the younger generation of learners. The goal of this educational endeavor was to introduce medical students to the field of Sleep Medicine through the platform of Student Interest Group in Neurology (SIGN).

Methods

An interactive session was conducted for SIGN at the University of Minnesota. 24 second-year medical students were divided into 6 groups. The session consisted of introduction, videos of common sleep disorders and interactive briefing afterward. 5-point Likert scale pre and post-session surveys were administered to measure the level of knowledge regarding sleep, familiarity with diagnostic tools, available education, pathways to Sleep Medicine, learner’s interest and impact of the session. Wilcoxon matched-pairs signed-rank test was performed to compare pre- and post-surveys.

Results

There was a significant improvement in measures of students’ knowledge about sleep diagnostic modalities (p =7.8*10-5), education received (p= 3.2*10-5) and pathways to sleep medicine (p=4.1*10-5). Survey also showed improvement in students’ interest in pursuing a Sleep Medicine career (p=0.07). There was no difference in knowledge about the importance of sleep for health (p=0.69). All of the students found the session to be informative.

Conclusion

Early exposure to sleep disorders in interactive format was well received by the medical students with significant improvement in scores regarding sleep education, awareness of diagnostic modalities, career pathway and interest in sleep medicine (p=0.07). Integration of exposure to Sleep Medicine within the medical curriculum in an innovative format should be done to instigate interest in this field. Further larger studies are warranted to evaluate the changes in the students’ interest in the subspecialty with an introduction in the early stages of their career.

Support

 

Contrast-Enhanced 3D-FLAIR Imaging of the Optic Nerve and Optic Nerve Head: Novel Neuroimaging Findings of Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

The sensitivity of contrast-enhanced 3D-FLAIR has not been assessed in patients with idiopathic intracranial hypertension. The purpose of this study was to evaluate whether hyperintensity of the optic nerve/optic nerve head on contrast-enhanced 3D-FLAIR imaging is associated with papilledema in patients with idiopathic intracranial hypertension.

MATERIALS AND METHODS

A retrospective review was conducted from 2012 to 2015 of patients with clinically diagnosed idiopathic intracranial hypertension and age- and sex-matched controls who had MR imaging with contrast-enhanced 3D-FLAIR. Two neuroradiologists graded each optic nerve/optic nerve head on a scale of 0-3. This grade was then correlated with the Frisén Scale, an ophthalmologic scale used for grading papilledema from 0 (normal) to 5 (severe edema). To estimate the correlation between the MR imaging and Frisén scores, we calculated the Kendall τ coefficient.

RESULTS

Forty-six patients (3 men, 43 women) with idiopathic intracranial hypertension and 61 controls (5 men, 56 women) with normal findings on MR imaging were included in this study. For both eyes, there was moderate correlation between the 2 scales (right eye: τ = 0.47; 95% CI, 0.31-0.57; left eye: τ = 0.38; 95% CI, 0.24-0.49). Interreader reliability for MR imaging scores showed high interreader reliability (right eye: κ = 0.76; 95% CI, 0.55-0.88; left eye: κ = 0.87; 95% CI, 0.78-0.94). Contrast-enhanced 3D-FLAIR imaging correlates with the Frisén Scale for moderate-to-severe papilledema and less so for mild papilledema.

CONCLUSIONS

Hyperintensity of the optic nerve/optic nerve head on contrast-enhanced 3D-FLAIR is sensitive for the detection of papilledema in patients with idiopathic intracranial hypertension, which may be useful when prompt diagnosis is crucial.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Amelioration of experimental colitis by Copaxone is associated with class-II-restricted CD4 immune blocking

Copaxone modifies TH1 immune response in multiple sclerosis. As Crohn's disease shares TH1 predominance, this study came to investigate the anti-inflammatory response of Copaxone in animal model of colitis.

METHODS

Colitis was induced by intra-rectal instillation of TNBS in 2 animal groups; one of them was daily treated intraperitoneally by 300 mug Copaxone starting 48 h post-colitis induction. Both colitis groups were compared to naive group. Eight male C57Bl6 mice were used in each group. At day 12, distal colon was excised for standard scoring, splenocytes were isolated for FACS and serum cytokines were assessed. Splenocytes were in-vitro-stimulated with colitis protein extracts in the presence or absence of Copaxone. Lymphocytes were blocked by either MHC anti-class I or anti-class II antibodies prior to Copaxone administration.

RESULTS

Copaxone markedly alleviated macro/microscopic colitis scoring as they decreased from 2.9 +/- 1.1/2.6 +/- 0.8 in colitis group to 1.7 +/- 1/1.5 +/- 0.5 in Copaxone-treated mice (P = 0.03/P = 0.008, respectively) compared to 0 +/- 0/1 +/- 0 in naives (P < 0.001/P < 0.01, respectively). CD4 subsets significantly decreased following Copaxone administration as compared to naive mice (P = 0.05). Although Copaxone-treated mice manifested a block of both serum TH1/TH2 responses, only interferon gamma secreting CD4 cells significantly decreased. NK cells tend to increase following colitis induction (P = 0.08), however, they significantly decreased in Copaxone-treated animals (P = 0.006). NK-T followed NK pattern. Using in vitro studies, Copaxone showed amelioration of T-cell proliferation that was significantly blocked when cells were pre-incubated with anti-MHC class II but not class I antibodies.

CONCLUSIONS

Copaxone had class-II-restricted anti-inflammatory effect in our animal colitis model associated with CD4/NK/NKT/TH1/TH2 suppression.

Effect of prolonged methylprednisolone therapy in unresolving acute respiratory distress syndrome: a randomized controlled trial

CONTEXT

No pharmacological therapeutic protocol has been found effective in modifying the clinical course of acute respiratory distress syndrome (ARDS) and mortality remains greater than 50%.

OBJECTIVE

To determine the effects of prolonged methylprednisolone therapy on lung function and mortality in patients with unresolving ARDS.

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Medical intensive care units of 4 medical centers.

PARTICIPANTS

Twenty-four patients with severe ARDS who had failed to improve lung injury score (LIS) by the seventh day of respiratory failure.

INTERVENTIONS

Sixteen patients received methylprednisolone and 8 received placebo. Methylprednisolone dose was initially 2 mg/kg per day and the duration of treatment was 32 days. Four patients whose LIS failed to improve by at least 1 point after 10 days of treatment were blindly crossed over to the alternative treatment.

MAIN OUTCOME MEASURES

Primary outcome measures were improvement in lung function and mortality. Secondary outcome measures were improvement in multiple organ dysfunction syndrome (MODS) and development of nosocomial infections.

RESULTS

Physiological characteristics at the onset of ARDS were similar in both groups. At study entry (day 9 [SD, 3] of ARDS), the 2 groups had similar LIS, ratios of PaO2 to fraction of inspired oxygen (FIO2), and MODS scores. Changes observed by study day 10 for methylprednisolone vs placebo were as follows: reduced LIS (mean [SEM], 1.7 [0.1] vs 3.0 [0.2]; P<.001); improved ratio of PaO2 to FIO2 (mean [SEM], 262 [19] vs 148 [35]; P<.001); decreased MODS score (mean [SEM], 0.7 [0.2] vs 1.8 [0.3]; P<.001); and successful extubation (7 vs 0; P=.05). For the treatment group vs the placebo group, mortality associated with the intensive care unit was 0 (0%) of 16 vs 5 (62%) of 8 (P=.002) and hospital-associated mortality was 2 (12%) of 16 vs 5 (62%) of 8 (P=.03). The rate of infections per day of treatment was similar in both groups, and pneumonia was frequently detected in the absence of fever.

CONCLUSIONS

In this study, prolonged administration of methylprednisolone in patients with unresolving ARDS was associated with improvement in lung injury and MODS scores and reduced mortality.

Nutrition knowledge and obesity of adults in community residences

Variation in nutrition knowledge of adults with mild or moderate mental retardation (30 obese, 27 nonobese) from four community agencies was examined as a function of their body mass and level of mental retardation. They completed a nutrition knowledge test adapted for individuals with mental retardation. Multiple regression analyses revealed significant effects of level of mental retardation and body mass on nutrition knowledge. Adults with mild mental retardation possessed greater nutrition knowledge than did those with moderate mental retardation, and obese individuals possessed more knowledge than did nonobese individuals. The unexpected relation between nutrition knowledge and degree of obesity implies an influential role for environmental factors in the development of obesity.

Prevalence, incidence, and correlates of syphilis seroreactivity in multiethnic San Francisco neighborhoods

To examine the extent of infection with syphilis in an inner-city community, we determined the prevalence, incidence, and correlates of syphilis seroreactivity in a representative sample of unmarried whites, African Americans, and Hispanics living in San Francisco during 1988 to 1989 and again 1 year later in 1989 to 1990. One thousand seven hundred seventy single men and women aged 20 to 44 were surveyed in a random household sample drawn from three neighborhoods of varying geographic and cultural characteristics. Syphilitic infection was determined by testing specimens with the microhemagglutination assay for antibodies to Treponema pallidum (MHA-TP). Of blood samples available from 1262 participants from the initial survey, 32 (2.5%) were MHA-TP reactive. After adjustment for age, a reactive syphilis serology was significantly predicted (P < 0.05) by African American race, homosexual activity (men), and less education. In homosexually active men, lifetime number of male sex partners and the presence of antibody to the human immunodeficiency virus (HIV) significantly predicted syphilis seroreactivity (P < 0.01). One year later, of 841 specimens available for testing, an additional 13 (1.5%) had become MHA-TP reactive. Eleven (85%) of the new cases were in heterosexual men and women. Although San Francisco citywide incidence data indicate that syphilis may be decreasing for the city as a whole, incidence data on a community level suggests that syphilitic infection is increasing in high-risk heterosexual communities. Thus, syphilis prevention programs should rely on serologic testing at the community level to plan effective intervention strategies.

Correlates of condom use among black, Hispanic, and white heterosexuals in San Francisco: the AMEN longitudinal survey. AIDS in Multi-Ethnic Neighborhoods survey

We examined correlates of condom use among heterosexual whites, blacks, and Hispanics (ages 20-45 years) with an human immunodeficiency virus (HIV) risk factor in a community-based longitudinal sample (San Francisco; n = 716). Lag models were used to examine hypothesized antecedents of condom use at wave 2. High levels of condom use were associated with labeling one's sexual behavior as risky for HIV infection, high levels of condom enjoyment and commitment to use condoms, good sexual communication practices, gender (trend), and marital status. The results support the need for wide-ranging intervention programs that stimulate people to make personal risk assessments, teach basic sexual skills, and direct those in need of intensive help to appropriate agencies.

Crack cocaine use and high-risk behaviors among sexually active black adolescents

The recent spread of crack cocaine use among inner-city teenagers has been accompanied by dramatic increases in juvenile delinquency and sexually transmitted diseases (STDs) among teenagers. This study examined the prevalence of five factors which promote STDs, including human immunodeficiency virus (HIV), among a sample of sexually active black adolescent crack users and non-users from the San Francisco Bay Area. Significant differences were observed between these groups with respect to history of engaging in sexual intercourse under the influence of drugs or alcohol, exchanging sexual favors for drugs or money, condom use in the most recent sexual encounter, and having five or more sexual partners in the last year. Approximately 63% of all respondents reported engaging in at least one of these risk behaviors. In multiple logistic regression analysis, reporting one or more of these STD/HIV risk behaviors was significantly associated with crack use and having one or more relatives who used drugs. Intervention efforts need to address both individual and environmental risk factors in order to reduce teens' risk for STDs, including HIV.

Prevalence and correlates of herpes simplex infections. The population-based AIDS in Multiethnic Neighborhoods Study

OBJECTIVE

To examine the extent and correlates of infection with herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in an inner-city community, we studied the prevalence of antibodies to these viruses and their association with risk behaviors in a representative sample of unmarried white, black, and Hispanic adults living in San Francisco, Calif.

DESIGN

Cross-sectional, community-based, random household survey.

PARTICIPANTS

In 1988 and 1989, we surveyed 1770 unmarried men and women aged 20 to 44 years from three San Francisco neighborhoods of varying geographic and cultural characteristics.

MAIN OUTCOME MEASURES

HSV-1 and HSV-2 antibodies based on an immunodot assay using type-specific glycoproteins gG-1 and gG-2.

RESULTS

Of blood samples from 1212 participants available for testing, 750 (62%) had HSV-1 antibodies and 400 (33%) had HSV-2 antibodies. After controlling for other variables, HSV-1 antibody was significantly correlated (P less than .05) with older age (in heterosexual men, women, and homosexually active men), less education (in heterosexual men and women), and Hispanic (especially those not born in the United States) or black race. HSV-2 antibody was significantly correlated (P less than .05) with female gender, number of lifetime sexual partners and older age (in heterosexual men and women), and low levels of education and black or Hispanic race (in women). Among those with antibody to HSV-2, only 28 (19%) of 149 men and 32 (13%) of 251 women reported a history of genital herpes. However, most men (62%) and women (84%) who reported a history of genital herpes had HSV-2 antibodies. We observed a similar pattern (low sensitivity and moderate specificity) for a history of facial herpes and the presence of HSV-1 antibodies. After controlling for other variables, HSV-2 antibodies were associated with a lower frequency of HSV-1 antibodies among homosexual men infected with the human immunodeficiency virus.

CONCLUSIONS

HSV-1 antibodies were found in nearly two thirds of single urban adults and were most common among Hispanics not born in the United States. HSV-2 antibodies were found in one third of this population and were associated with risk behaviors for sexually transmitted diseases. For both facial and genital herpes infections, self-reporting of infection was very insensitive and moderately specific.

Risk for AIDS in multiethnic neighborhoods in San Francisco, California. The population-based AMEN Study

To examine the actual and potential spread of human immunodeficiency virus (HIV) from an acquired immunodeficiency syndrome (AIDS) epicenter to surrounding neighborhoods, we studied the prevalence of the viral infection and AIDS risk behaviors from 1988 to 1989 in a representative sample of unmarried whites, African Americans, and Hispanics living in San Francisco. We surveyed 1,770 single men and women aged 20 to 44 years (a 64% response rate) in a random household sample drawn from 3 neighborhoods of varying geographic and cultural proximity to the Castro District where the San Francisco epidemic began. Of 1,369 with blood tests, 69 (5%) had HIV antibodies; all but 5 of these reported either homosexual activity (32% HIV-positive; 95% confidence interval [CI] = 23%, 41%), injection drug use (5% HIV-positive; CI = 1%, 14%), or both (59% HIV-positive; CI 42%, 74%). Homosexual activity was more common among white men than among African-American or Hispanic men, but the proportion of those infected was similar in the 3 races. Both the prevalence of homosexually active men and the proportion infected were much lower in the 2 more outlying neighborhoods. Risk behaviors in the past year for acquiring HIV heterosexually--sex with an HIV-infected person or homosexually active man or injection drug user, unprotected sexual intercourse with more than 4 partners, and (as a proxy) having a sexually transmitted disease--were assessed in 1,573 neighborhood residents who were themselves neither homosexually active men nor injection drug users. The prevalence of reporting at least 1 of these risk behaviors was 12% overall, and race-gender estimates ranged from 5% among Hispanic women to 21% among white women. We conclude that in San Francisco, infection with HIV is rare among people who are neither homosexually active nor injection drug users, but the potential for the use spread of infection is substantial, as 12% of this group reported important risk behaviors for acquiring the virus heterosexually.

An Analysis of the Predictability of Hypoxemia Following Vertical Banded Gastroplasty

Postoperative (post-op) hypoxemia is unpredictable, often undetected by physical examination, sometimes fatal. We studied 45 morbidly obese patients with an average age of 37, including 16 smokers, having vertical banded gastroplasty (VBG) for useful preoperative (preop) predictor(s) of post-op hypoxemia during the first five days following VBG. Patient blood gases (arterial blood oxygen, P&infa;O&inf2; in mmHg), pre-op and five post-op days (POD), after 30 min in room air were: pre-op, 85 +/- 9; POD1, 63 +/- 9*; POD2, 61 +/- 9*; POD3, 63 +/- 10*; POD4, 63 +/- 9* POD5, 64 +/- 1 * (* p < 0.05, Student's t-test compared with pre-op). Linear regression showed no practical, predictive value for P.02 for age, Body Mass Index (BMI), pulmonary function tests (PFTs), smokers or preop P&infa;O&inf2;. Post-op atelectasis occurred in 84% of patients, mostly the posterior basilar regions on chest X-ray. No patient developed clinically diagnostic pneumonia. VBG patients experienced profound hypoxemia post-op, the lowest on POD2. There is no reliable method to predict which patient may develop severe hypoxemia. It is, therefore, extremely helpful to uniformly monitor P&infa;O&inf2; post-op in morbidly obese patients.

Postthaw stability of fibrinogen in cryoprecipitate stored between 1 and 6 degrees C

The fibrinogen activity in thawed cryoprecipitate stored between 1 and 6 degrees C is maintained essentially unchanged in most bags for a month. Occasionally, a bag will have a reduction in fibrinogen. If pooling has not occurred, thawed cryoprecipitate should be useful as a source of fibrinogen for a period of time considerably in excess of the 6 hours allowed for its use as a source of factor VIII or von Willebrand factor.

Hereditary hemorrhagic telangiectasia. A family study

The authors report a comprehensive evaluation of the hemostatic system in eight related patients with hereditary hemorrhagic telangiectasia (HHT). Unlike in previous reports, they could find no evidence for abnormalities in platelet aggregation or for qualitative abnormalities of the Factor VIII complex. The authors did identify a subgroup of the more severely affected patients in whom Factor VIIIc levels were increased, with shortened activated partial thromboplastin times (APTTs) associated with mild elevations of antithrombin III.

Cat-eye syndrome with different marker chromosomes in a mother and daughter

Except for atypical eye findings in the daughter, a mother and daughter with bisatellited marker chromosomes had abnormalities consistent with cat-eye syndrome. The mother's marker chromosome (mar number 1) is derived from one 22 and another acrocentric, possibly also a 22; the daughter's marker (mar number 2) may be an iso-dicentric, inv-dup (22) derivative of mar number 1. The mother has a tertiary trisomy translocation chromosome composed of at least one and perhaps two copies of 22pter----q11.2, whereas the daughter clearly has a secondary trisomy 22pter----q11.2 isochromosome, confirming this region as a cause of cat-eye syndrome. Results of hybridization using a unique sequence probe localized to 22q11 are consistent with the interpretation that both ends of both marker chromosomes are derived from 22.

The use of methacholine inhalation, methacholine skin testing, distilled water inhalation challenge and eosinophil counts in the evaluation of patients presenting with cough and/or nonwheezing dyspnea

Twenty-four patients presenting with cough and/or nonwheezing dyspnea were evaluated with methacholine inhalation challenge (MC), distilled water inhalation challenge (DC), intracutaneous tests to varying concentrations of methacholine, total eosinophil counts (TEC), sinus and chest x-rays. We found a statistically significant difference (P less than .005) in the mean TEC in those patients with a positive MC test and those with a negative test. Hyperreactivity of the airways to methacholine in asthmatics is not found in the skin. Distilled water inhalation did not serve to substitute for MC as a test of hyperreactive airways. The TEC is an excellent screening test as a predictor of patients with cough or dyspnea who have hyperreactive airways.

Correlation between serial pulmonary function tests and fiberoptic bronchoscopy in patients with Pneumocystis carinii pneumonia and the acquired immune deficiency syndrome

The records of 9 adult male patients with the acquired immune deficiency syndrome (AIDS) and biopsy-proved Pneumocystis carinii pneumonia were reviewed to determine the correlation between serial pulmonary function tests and the presence or absence of Pneumocystis organisms in subsequent bronchoscopy specimens. At diagnosis, total lung capacity (TLC) or vital capacity (VC) was abnormally low in 4 patients (44%) and diffusing capacity (DLCO) was abnormally low in 8 patients (89%). The ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) was elevated in all patients. After 21 to 47 days of specific therapy for Pneumocystis pneumonia, changes in DLCO, TLC, VC, and FEV1/FVC did not correlate with the presence or absence of Pneumocystis organisms in bronchoscopy specimens from 7 patients. However, changes in DLCO 105 to 258 days after diagnosis seemed to correlate with the late response to treatment in 6 patients. These results suggest that decisions to terminate specific therapy for Pneumocystis pneumonia in patients with AIDS should not be based on short-term changes in pulmonary function.