Skin Antisepsis before Surgical Fixation of Extremity Fractures

BACKGROUND

Studies evaluating surgical-site infection have had conflicting results with respect to the use of alcohol solutions containing iodine povacrylex or chlorhexidine gluconate as skin antisepsis before surgery to repair a fractured limb (i.e., an extremity fracture).

METHODS

In a cluster-randomized, crossover trial at 25 hospitals in the United States and Canada, we randomly assigned hospitals to use a solution of 0.7% iodine povacrylex in 74% isopropyl alcohol (iodine group) or 2% chlorhexidine gluconate in 70% isopropyl alcohol (chlorhexidine group) as preoperative antisepsis for surgical procedures to repair extremity fractures. Every 2 months, the hospitals alternated interventions. Separate populations of patients with either open or closed fractures were enrolled and included in the analysis. The primary outcome was surgical-site infection, which included superficial incisional infection within 30 days or deep incisional or organ-space infection within 90 days. The secondary outcome was unplanned reoperation for fracture-healing complications.

RESULTS

A total of 6785 patients with a closed fracture and 1700 patients with an open fracture were included in the trial. In the closed-fracture population, surgical-site infection occurred in 77 patients (2.4%) in the iodine group and in 108 patients (3.3%) in the chlorhexidine group (odds ratio, 0.74; 95% confidence interval [CI], 0.55 to 1.00; P = 0.049). In the open-fracture population, surgical-site infection occurred in 54 patients (6.5%) in the iodine group and in 60 patients (7.3%) in the chlorhexidine group (odd ratio, 0.86; 95% CI, 0.58 to 1.27; P = 0.45). The frequencies of unplanned reoperation, 1-year outcomes, and serious adverse events were similar in the two groups.

CONCLUSIONS

Among patients with closed extremity fractures, skin antisepsis with iodine povacrylex in alcohol resulted in fewer surgical-site infections than antisepsis with chlorhexidine gluconate in alcohol. In patients with open fractures, the results were similar in the two groups. (Funded by the Patient-Centered Outcomes Research Institute and the Canadian Institutes of Health Research; PREPARE ClinicalTrials.gov number, NCT03523962.).

The applicability of the "surprise question" as a prognostic tool in patients with severe chronic comorbidities in a university teaching outpatient setting

BACKGROUND

Life expectancy in recent decades has increased the prevalence of chronic diseases in the population, requiring an approach to new health topics, such as discussions on quality of life and expectations about death and dying. The concept of advance directives (ADs) gives individuals the opportunity to make known their decisions about the treatments they would like to receive at the end of life. Despite the recognition of relevance in clinical practice, the applicability of the concept presents challenges, including establishing the appropriate prognosis for each patient and the ideal time to approach the patient. Some prognostic tools were developed, such as the surprise question (SQ): "Would you be surprised if your patient died in 12 months?", which is used in some clinical settings to predict patient deaths and to make decisions regarding ADs. The main objective of the present study was to evaluate the behavior of second-year resident physicians (PGY-2) when the SQ was applied.

METHOD

In our observational study, from July 1, 2016, to February 28, 2017, (PGY-2) in the Internal Medicine Residency Program (IMRP) applied SQ to all patients with multiple and varied chronic no communicable comorbidities, who were followed up at the general medicine outpatient clinic (GMOC) of a tertiary university hospital in São Paulo- Brazil. The frequency of the outcome (death or non-death within 12 months) was analyzed by correlating it with the clinical data (impact of the studied variables).

RESULTS

Eight hundred forty patients entered the study. Fitfty-two of them (6.2%) died within one year. PGY-2 predicted that two hundred and fourteen patients (25.5% of total) would die within a year (answer No to SQ), of which, 32 (14.9%) did so. The correct residents' prognosis for the subgroup of 626 patients (answer "Yes" to SQ) was NPV = 96.8% (CI = 95.4%-98.2%) and PPV = 14.9% (CI 10.1%-19, 6%). Answering "Yes" to SQ correlated negatively to addressing AD while the outcomes death and the answer No to SQ were positively correlated, according to the number of comorbidities.

CONCLUSION

The SQ, in addition to care, contributed to health education, communication and care planning shared by the doctor and patient.

Racial and Sex Disparities in Resident Attrition in Orthopaedic Surgery

Studies have suggested that female individuals and individuals from backgrounds under-represented in medicine (URiM) are at increased risk of attrition during residency. This likely exacerbates the lack of diversity in our field. The aims of this study were to (1) characterize demographic composition in orthopaedic residency from 2001 to 2018 and (2) determine the race/ethnicity and identify any disparities.

Methods

Demographic and attrition data from 2001 to 2018 were obtained from the Association of American Medical Colleges. Attrition data comprised the following categories: withdrawals, dismissals, and transfers to another specialty. Analysis compared demographic composition and determined attrition rates with subgroup analysis by race/ethnicity and sex.

Results

From 2001 to 2018, female orthopaedic residents increased from 8.77% to 15.54% and URiM residents from 9.49% to 11.32%. The overall and unintended attrition rates in orthopaedic surgery were 3.20% and 1.15%, respectively. Among female residents, the overall and unintended attrition rates were 5.96% and 2.09% compared with 2.79% and 1.01%, respectively, in male residents. URiM residents had overall and unintended attrition rates of 6.16% and 3.11% compared with 2.71% and 0.83%, respectively, for their White counterparts. Black/African American residents had an attrition rate of nearly 10%. Female residents averaged 12.9% of all residents but 24% of those leaving orthopaedics. URiM residents were 10.14% of all residents but 19.51% of those experiencing attrition. In logistic regression models, female residents had a relative risk (RR) of 2.20 (p < 0.001) for experiencing all-cause attrition and 2.09 (p < 0.001) for unintended attrition compared with male residents. Compared with their White male counterparts, URiM residents had a RR for overall and unintended attrition of 2.36 and 3.84 (p < 0.001), respectively; Black/African American residents had a RR for the same of 3.80 and 7.20 (p < 0.001), respectively.

Conclusion

Although female resident percentage has increased, orthopaedics continues to train fewer female surgeons than all other fields. Female and URiM residents in orthopaedic surgery are disproportionately affected by attrition. While recruitment has been the primary focus of diversity, equity, and inclusion efforts, this study suggests that resident retention through appropriately supporting residents during training is equally critical.

Racial and Sex Disparities in Resident Attrition Among Surgical Subspecialties

Importance

Racial and sex disparities are prevalent in surgical trainees. Although retrospective studies on resident attrition have been conducted for individual specialties, this study analyzes racial and sex differences in resident attrition among all surgical subspecialties over an 18-year period.

Objective

To evaluate the racial and sex differences in resident attrition among surgical specialties over an 18-year period.

Design, Setting, and Participants

This was a large, cross-sectional, database study that analyzed program-reported resident censuses (program information, resident demographics, and attrition status) obtained by the Association of American Medical Colleges from 2001 to 2018 for trainees in surgical residency programs. Data were analyzed from March 20, 2021, to June 8, 2022.

Main Outcomes and Measures

Demographic trends (including race and ethnicity and sex) for all surgical subspecialty training programs over an 18-year period. Resident attrition includes all-cause withdrawals, dismissals, and transfers to another specialty. Unintended attrition encompasses all withdrawals, dismissals, and transfers except for changing career plans.

Results

This study included 407 461 program-reported resident years collected from 112 205 individual surgical residents (67 351 male individuals [60.0%]). The mean percentage of female trainees was 40.0% (44 835) and increased over the study period. Sex disparity remained greatest in orthopedic surgery. Residents who were underrepresented in medicine (URiM) comprised 14.9% (16 695) of all surgical trainees but demonstrated a 2.1% decrease over the study period. Overall attrition rate among all specialties was 6.9% (7759), with an unintended attrition rate of 2.3% (2556). Female residents had a significantly higher relative risk (RR) of attrition (RR, 1.16; 95% CI, 1.11-1.22; P < .001) and unintended attrition (RR, 1.17; 95% CI, 1.08-1.26; P < .001) compared with their male counterparts. URiM residents were at significantly higher RR for attrition (RR, 1.40; 95% CI, 1.32-1.48; P < .001) and unintended attrition (RR, 1.92; 95% CI, 1.75-2.11; P < .001) compared with non-URiM residents. The highest attrition (10.6% [746 of 7043]) and unintended attrition (5.2% [367 of 7043]) rates were in Black/African American residents. The lowest attrition and unintended attrition rates were seen in White residents at 6.2% (4300 of 69 323) and 1.8% (1234 of 69 323), respectively. Black/African American residents were at disproportionate risk for attrition (RR, 1.66; 95% CI, 1.53-1.80; P < .001) and unintended attrition (RR, 2.59; 95% CI, 2.31-2.90; P < .001) compared with all other residents. Orthopedic surgery had the highest attrition (RR, 3.80; 95% CI, 2.84-5.09; P < .001) and unintended attrition (RR, 7.20; 95% CI, 4.84-10.71; P < .001) for Black/African American residents.

Conclusions and Relevance

Results of this cross-sectional study suggest that the percentage of female residents in surgical specialties has improved over the last 18 years, and the percentage of URiM residents has remained relatively unchanged. Risk for attrition and unintended attrition was significantly elevated for female and URiM residents, specifically Black/African Americans. These results highlight current racial and sex disparities in resident attrition and demonstrate the importance of developing strategies to recruit, retain, and support residents.

Increased Duration and Frequency of Lateral C-Arm Draping Does Not Increase Contamination Rates

This study sought to quantify the rate of culture-positive drape contamination with varying degrees of drape manipulation for intra-operative fluoroscopic imaging. In this prospective cohort study, 30 patients with operatively closed lower extremity fractures were evaluated. The clip-drape technique was employed to cover the emitter. Swab samples were collected for bacterial growth. A t-test was applied for statistical comparison. Three of 30 cases (10% of operations) showed evidence of contamination. There was no statistically significant difference between duration of drape use or the amount of drape manipulations. None of the 30 patients in this study developed surgical site infection 90-days post-surgery. The clip drape technique for lateral fluoroscopy appears to be effective in maintaining surgical field sterility. Moreover, the number of drape manipulations and length of time the drape was in use was not related to drape contamination. Level of Evidence: Therapeutic Level II. (Journal of Surgical Orthopaedic Advances 32(2):107-110, 2023).

Aqueous skin antisepsis before surgical fixation of open fractures (Aqueous-PREP): a multiple-period, cluster-randomised, crossover trial

BACKGROUND

Chlorhexidine skin antisepsis is frequently recommended for most surgical procedures; however, it is unclear if these recommendations should apply to surgery involving traumatic contaminated wounds where povidone-iodine has previously been preferred. We aimed to compare the effect of aqueous 10% povidone-iodine versus aqueous 4% chlorhexidine gluconate on the risk of surgical site infection in patients who required surgery for an open fracture.

METHODS

We conducted a multiple-period, cluster-randomised, crossover trial (Aqueous-PREP) at 14 hospitals in Canada, Spain, and the USA. Eligible patients were adults aged 18 years or older with an open extremity fracture treated with a surgical fixation implant. For inclusion, the open fracture required formal surgical debridement within 72 h of the injury. Participating sites were randomly assigned (1:1) to use either aqueous 10% povidone-iodine or aqueous 4% chlorhexidine gluconate immediately before surgical incision; sites then alternated between the study interventions every 2 months. Participants, health-care providers, and study personnel were aware of the treatment assignment due to the colour of the solutions. The outcome adjudicators and data analysts were masked to treatment allocation. The primary outcome was surgical site infection, guided by the 2017 US Centers for Disease Control and Prevention National Healthcare Safety Network reporting criteria, which included superficial incisional infection within 30 days or deep incisional or organ space infection within 90 days of surgery. The primary analyses followed the intention-to-treat principle and included all participants in the groups to which they were randomly assigned. This study is registered with ClinicalTrials.gov, NCT03385304.

FINDINGS

Between April 8, 2018, and June 8, 2021, 3619 patients were assessed for eligibility and 1683 were enrolled and randomly assigned to povidone-iodine (n=847) or chlorhexidine gluconate (n=836). The trial's adjudication committee determined that 45 participants were ineligible, leaving 1638 participants in the primary analysis, with 828 in the povidone-iodine group and 810 in the chlorhexidine gluconate group (mean age 44·9 years [SD 18·0]; 629 [38%] were female and 1009 [62%] were male). Among 1571 participants in whom the primary outcome was known, a surgical site infection occurred in 59 (7%) of 787 participants in the povidone-iodine group and 58 (7%) of 784 in the chlorhexidine gluconate group (odds ratio 1·11, 95% CI 0·74 to 1·65; p=0·61; risk difference 0·6%, 95% CI -1·4 to 3·4).

INTERPRETATION

For patients who require surgical fixation of an open fracture, either aqueous 10% povidone-iodine or aqueous 4% chlorhexidine gluconate can be selected for skin antisepsis on the basis of solution availability, patient contraindications, or product cost. These findings might also have implications for antisepsis of other traumatic wounds.

FUNDING

US Department of Defense, Canadian Institutes of Health Research, McMaster University Surgical Associates, PSI Foundation.

COVID-19 Shelter-In-Place Orders Associated With Delayed Presentation and Deep Venous Thrombosis in Geriatric Hip Fractures

Geriatric hip fractures benefit from timely surgery. At the onset of the corona-virus disease 2019 (COVID-19) pandemic, shelter-in-place (SIP) orders were mandated in high-risk cities. The authors hypothesized that geriatric patients with hip fractures were more likely to present to the hospital greater than 24 hours after injury during SIP orders. They retrospectively reviewed patients 65 years or older who presented with hip fractures between March 20, 2020, and May 24, 2020 (SIP group), and between March 20, 2019, and May 24, 2019 (historical group). Primary outcomes were incidence of presentation greater than 24 hours after injury and mean number of days between injury and presentation. Secondary outcomes were incidence of preoperative deep venous thrombosis (DVT) and 30- and 90-day mortality rates. Thirty-three patients comprised the SIP group, and 50 patients comprised the historical group. There were no significant differences in their demographics or medical comorbidities. The SIP group was more likely to present greater than 24 hours after injury (P=.05) and presented a greater number of days after injury (P=.02). There was a significant difference in the incidence of preoperative DVT (P=.03). There were no significant differences in 30- and 90-day mortality rates. Geriatric patients who sustained hip fractures during SIP restrictions for COVID-19 were more likely to present greater than 24 hours after injury, have a greater number of days between injury and presentation, and be diagnosed with a preoperative DVT. [Orthopedics. 2021;44(4):223-228.].

Low Adherence to Recommended Guidelines for Open Fracture Antibiotic Prophylaxis

BACKGROUND

Prompt administration of antibiotics is a critical component of open fracture treatment. Traditional antibiotic recommendations have been a first-generation cephalosporin for Gustilo Type-I and Type-II open fractures, with the addition of an aminoglycoside for Type-III fractures and penicillin for soil contamination. However, concerns over changing bacterial patterns and the side effects of aminoglycosides have led to interest in other regimens. The purpose of the present study was to describe the adherence to current prophylactic antibiotic guidelines.

METHODS

We evaluated the antibiotic-prescribing practices of 24 centers in the U.S. and Canada that were participating in 2 randomized controlled trials of skin-preparation solutions for open fractures. A total of 1,234 patients were evaluated.

RESULTS

All patients received antibiotics on the day of admission. The most commonly prescribed antibiotic regimen was cefazolin monotherapy (53.6%). Among patients with Type-I and Type-II fractures, there was 61.1% compliance with cefazolin monotherapy. In contrast, only 17.2% of patients with Type-III fractures received the recommended cefazolin and aminoglycoside therapy, with an additional 6.7% receiving piperacillin/tazobactam.

CONCLUSIONS

There is moderate adherence to the traditional antibiotic treatment guidelines for Gustilo Type-I and Type-II fractures and low adherence for Type-III fractures. Given the divergence between current practice patterns and prior recommendations, high-quality studies are needed to determine the most appropriate prophylactic protocol.

Metabolic factors and post-traumatic arthritis may influence the increased rate of surgical site infection in patients with human immunodeficiency virus following total hip arthroplasty

BACKGROUND

The impact of CD4+ T-cell count and highly active antiretroviral therapy (HAART) on the rate of surgical site infection (SSI) in patients with human immunodeficiency virus (HIV) undergoing total hip arthroplasty is still unclear. The goals of this study were to assess the rate of perioperative infection at a large tertiary care referral center and to identify risk factors in HIV+ patients undergoing total hip arthroplasty (THA).

METHODS

This study was a prospective, observational study at a single medical center from 2000-2017. Patients who were HIV+ and underwent THA were followed from the preoperative assessment period, through surgery and for a 2-year follow-up period.

RESULTS

Sixteen of 144 HIV+ patients (11%) undergoing THA developed perioperative surgical site infections. Fourteen patients (10%) required revision THA within a range of 12 to 97 days after the initial surgery. The patients' mean age was 49.6 ± 4.5 years, and the most common diagnosis prompting THA was osteonecrosis (96%). Patients who developed SSI had a lower waist-hip ratio (0.86 vs. 0.93, p = 0.047), lower high density lipoprotein cholesterol (45.8 vs. 52.5, p = 0.015) and were more likely to have post-traumatic arthritis (12.5% vs. 0%, p = 0.008). Logistic regression analysis demonstrated that current alcohol use and higher waist-hip ratio were significant protectors against infection (p < 0.05). No other demographic, medical, immunologic parameters, or specific HAART regimens were associated with perioperative infection.

CONCLUSIONS

Immunologic status as measured by CD4+ cell count, HIV viral load, and medical therapy do not appear to influence the development of SSI in HIV+ patients undergoing THA. Metabolic factors and post-traumatic arthritis may influence the increased rate of infection in HIV+ patients following THA.

A Comparison in Outcomes of Preoperative Single-shot versus Continuous Catheter Fascia Iliaca Regional Anesthesia in Geriatric Hip Fracture Patients

BACKGROUND

Fascia iliaca nerve blocks relieve pain in geriatric hip fracture patients and can be administered via a single-shot or continuous catheter. We compared perioperative opioid consumption and pain scores between these two blocks.

METHODS

We performed a prospective, observational cohort study, including geriatric hip fracture patients who received a preoperative block. We compared morphine milligram equivalent (MME) consumption and visual analog scale (VAS) pain scores between single-shot and continuous fascia iliaca blocks at multiple time points: preoperative and on postoperative (POD) day 0, 1, and 2. We compared the change in preoperative total and hourly opioid consumption before and after block placement within and between groups. Secondary outcomes included opioid related adverse events, length of stay, and readmission rates.

RESULTS

107 patients were analyzed, 66 received a single-shot and 41 a continuous block. No significant differences were found between both blocks at any time point for median MME consumption or pain scores. MME [IQR]: preoperative 20.5 [6.0,48.8] vs. 24.0 [8.8,48.0], p=0.95; POD0 6.0 [0.0,18.6] vs. 10.0 [0.0,14.0], p=0.52; POD1 12.0 [0.0,30.0] vs. 18.0 [5.0,24.0], p=0.69; POD2 6.0 [0.0,21.2] vs. 12.0 [0.0,24.0], p=0.54. VAS [IQR]: preoperative 4.0 [2.2,5.3] vs. 4.6 [3.2,5.3], p=0.34; POD0 1.3 [0.0,3.7] vs. 2.5 [0.0,3.6], p=0.73; POD1 2.9 [1.7,4.4] vs. 3.7 [1.5,4.7], p=0.59; POD2 2.4 [1.0,4.4] vs. 3.3 [1.9,4.2], p=0.18. Preoperative MME/hr significantly decreased after the block for both groups: 1.05 [0.0,2.2] to 0.0 [0.0,0.0], p < 0.001; 1.4 [0.6,3.1] to 0.0 [0.0,0.1], p < 0.001. The reduction in MME/hr between groups was not significantly different: 0.9 [0.0,1.9] vs. 1.4 [0.6,3.1], p = 0.067. We found no significant differences in secondary outcomes between groups.

CONCLUSIONS

We report no differences in opioid use and pain scores between single-shot and continuous catheter fascia iliaca nerve blocks. Both blocks similarly reduce preoperative opioid consumption.

Pain Management with Early Regional Anesthesia in Geriatric Hip Fracture Patients

BACKGROUND

Geriatric hip fracture patients are susceptible to the adverse effects of opioid-induced analgesia. Fascia iliaca blocks (FIBs) have emerged as an analgesic technique for this population. There are limited data on a preoperative FIB's effect on perioperative opioid intake. We hypothesized that preoperative FIB would reduce perioperative opioid consumption, measured in morphine milliequivalents (MMEs).

DESIGN

This is a prospective observational study.

SETTING

A level 1 trauma center in California.

PARTICIPANTS

From March 2017 to December 2017, patients 65 years and older presenting with a hip fracture received a preoperative FIB and were prospectively observed. This cohort was compared with a historical control.

INTERVENTION

All prospectively enrolled patients were given FIBs. For a single-shot FIB, a 30- to 40-mL bolus of 0.25% bupivacaine with 1:200,000 epinephrine was injected. For a continuous FIB, a bolus of 10 to 20 mL of 0.2% bupivacaine was injected, followed by a continuous infusion of 0.2% bupivacaine at 6 mL/h ending on the morning of postoperative Day 1.

RESULTS

A total of 725 patients were included in this study, with 92 in the prospectively collected cohort. The mean age of this cohort was 84.2 (standard deviation = 8.4) years, and 69.2% were female. Patients who received a preoperative FIB consumed less MME preoperatively, 18.0 (interquartile range = 6.0-44.5) versus 29.5 (interquartile range = 6.0-56.5) (P = .007), with no change in pain scores. No differences were found in postoperative opioid consumption between groups. There was no difference in MME or pain score in patients with dementia. Subgroup analysis based on fracture pattern (femoral neck and intertrochanteric) demonstrated a significant decrease in preoperative MME consumption in femoral neck fractures only, 12.0 (interquartile range = 5.0-24.0) versus 29.0 (interquartile range = 12.0-59.0) (P < .001).

CONCLUSION

FIBs reduce preoperative opioid intake and have low rates of opioid-related adverse events in geriatric hip fracture patients.

LEVEL OF EVIDENCE

The level of evidence was II.

Time to Block: Early Regional Anesthesia Improves Pain Control in Geriatric Hip Fractures

BACKGROUND

Fascia iliaca nerve blocks (FIBs) anesthetize the thigh and provide opioid-sparing analgesia for geriatric patients with hip fracture awaiting a surgical procedure. FIBs are recommended for preoperative pain management; yet, block administration is often delayed for hours after admission, and delays in pain management lead to worse outcomes. Our objective was to determine whether opioid consumption and pain following a hip fracture are affected by the time to block (TTB). We also examined length of stay and opioid-related adverse events.

METHODS

This prospective cohort study included patients who were ≥60 years of age, presented with a hip fracture, and received a preoperative FIB from March 2017 to December 2017. Individualized care timelines, including the date and time of admission, block placement, and surgical procedure, were created to evaluate the effect that TTB and time to surgery (TTS) had on outcomes. Patterns among TTB, TTS, and morphine milligram equivalents (MME) were investigated using the Spearman rho correlation. For descriptive purposes, we divided patients into 2 groups based on the median TTB. Multivariable regression for preoperative MME and length of stay was performed to assess the effect of TTB.

RESULTS

There were 107 patients, with a mean age of 83.3 years, who received a preoperative FIB. The median TTB was 8.5 hours. Seventy-two percent of preoperative MME consumption occurred before block placement (pre-block MME). A longer TTB was most strongly correlated with pre-block MME (rho = 0.54; p < 0.001), and TTS was not correlated. Patients with a faster TTB consumed fewer opioids preoperatively (12.0 compared with 33.1 MME; p = 0.015), had lower visual analog scale scores for pain on postoperative day 1 (2.8 compared with 3.5 points; p = 0.046), and were discharged earlier (4.0 compared with 5.5 days; p = 0.039). There were no differences in preoperative pain scores, postoperative opioid consumption, delirium, or opioid-related adverse events. Multivariate regression showed that every hour of delay in TTB was associated with a 2.8% increase in preoperative MME and a 1.0% increase in the length of stay.

CONCLUSIONS

Faster TTB in geriatric patients with hip fracture may reduce opioid use, pain, and length of stay.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Nationwide Analysis of Femoral Neck Fractures in Elderly Patients: A Receding Tide

BACKGROUND

Geriatric femoral neck fractures are associated with substantial morbidity and medical cost. We evaluated the incidence and management trends of femoral neck fractures in recent years in the U.S.

METHODS

Patient data from 2003 through 2013 were obtained from the Nationwide Inpatient Sample database. Femoral neck fractures in patients ≥65 years old were identified and grouped using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes for internal fixation, hemiarthroplasty, or total hip arthroplasty (THA). The nationwide incidence of femoral neck fractures was calculated and presented as an age-adjusted population rate. Univariable methods were used for trend analysis and comparisons between groups. Logistic regression modeling was used to analyze complications.

RESULTS

From 2003 to 2013, we identified 808,940 femoral neck fractures in patients ≥65 years old. The national age-adjusted incidence of femoral neck fractures decreased from 242 per 100,000 U.S. adults in 2003 to 146 in 2013. The proportion of fractures managed operatively with THA increased over time (5.9% in 2003 versus 7.4% in 2013; p < 0.001). Concurrently, the use of hemiarthroplasty declined (65.1% versus 63.6%; p < 0.001). In 2013, the median age of the patients treated with THA was significantly younger (77.3 years) compared with that in the hemiarthroplasty and internal fixation groups (83.2 and 82.0 years). The THA group had significantly higher median initial hospital costs ($17,097) compared with the hemiarthroplasty and internal fixation groups ($14,776 and $10,462).

CONCLUSIONS

In the last decade, the total number and population rate of femoral neck fractures in the elderly declined significantly. There was a modest but significant increase in the utilization of THA.

CLINICAL RELEVANCE

This report identifies the changing trends in clinical practice in the treatment of geriatric femoral neck fractures in the U.S. Treating physicians should be aware of these trends, which include a decreasing national incidence of geriatric femoral neck fractures as well as an increase in the use of THA.

Increasing Use of Reverse Total Shoulder Arthroplasty for Proximal Humerus Fractures in Elderly Patients

This study described surgical treatment patterns for proximal humerus fractures among elderly patients, focusing on reverse total shoulder arthroplasty (TSA), and evaluated how the type of fixation affects inpatient factors (cost, length of stay), transfusion rates, and patient disposition (home vs skilled nursing facility). With Nationwide Inpatient Sample data from 2011 to 2013, the authors identified patients 65 years and older who had proximal humerus fractures and divided them into 3 groups: (1) open reduction and internal fixation (ORIF); (2) hemiarthroplasty; and (3) reverse TSA. From 2011 to 2013, 38,729 surgically treated proximal humerus fractures were identified. The rate of reverse TSA increased 1.8-fold during this time, from 13% of operative cases in 2011 to 24% of operative cases in 2013 (P<.001). At the same time, the rates of hemiarthroplasty and ORIF decreased (hemiarthroplasty, from 28% to 21%; ORIF, from 59% to 55%). Although reverse TSA accounted for 32.2% of arthroplasty procedures for proximal humerus fractures in 2011, this value was 53.3% in 2013 (P<.001). In 2013, mean total hospital cost for reverse TSA was $24,154, which was significantly higher than that for ORIF ($16,269) or hemiarthroplasty ($19,175) (P<.001). In a multivariable model, patients undergoing reverse TSA were less likely than those undergoing hemiarthroplasty to be discharged to a skilled nursing facility (odds ratio, 0.75; P=.027). The national rate of reverse TSA nearly doubled from 2011 to 2013. As of 2013, reverse TSA replaced hemiarthroplasty as the most commonly performed arthroplasty procedure for proximal humerus fractures for patients 65 years and older. Patients undergoing reverse TSA were more likely than those undergoing hemiarthroplasty to be discharged home. [Orthopedics. 2017; 40(6):e982-e989.].

Primary total elbow arthroplasty for distal humeral fractures in elderly patients: a nationwide analysis

BACKGROUND

Displaced intra-articular distal humeral fractures are a challenging injury in elderly patients. High rates of complications have led to the increasing use of total elbow arthroplasty (TEA) for primary treatment. This study presents US nationwide trends in primary TEA for distal humeral fractures in elderly patients (65 years and older) from 2002 to 2012. We hypothesized that there was an increase in the rate of TEA utilization.

METHODS

Data were obtained from the Nationwide Inpatient Sample for the years 2002 to 2012. All inpatients 65 years and older with distal humeral fractures were identified and were divided into 2 subgroups based on the operation they received: (1) TEA and (2) open reduction-internal fixation (ORIF).

RESULTS

Between 2002 and 2012, the annual frequency of TEA for elderly patients with distal humeral fractures increased 2.6-fold, with 147 patients in 2002 and 385 in 2012. In 2012, TEA was performed in 13% of operatively treated distal humeral fractures compared with only 5.1% in 2002 (P < .05). Mean hospital charges increased significantly for both the ORIF and TEA groups from 2002 to 2012. The average hospital charge for TEA in 2012 was $85,365, which was $16,358 higher than that for patients who underwent ORIF (P < .05).

CONCLUSION

The national rate of primary TEA for the acute management of distal humeral fractures in elderly patients has increased significantly over the past 10 years. Given the significant complexity, long-term restrictions, and risks associated with TEA, this increasing trend should be analyzed closely.

Temporising external fixation of calcaneus fractures prior to definitive plate fixation: a case series

INTRODUCTION

Surgical management of calcaneus fractures is technically demanding and has a high risk of wound complications. These fractures are traditionally managed with splinting until swelling has subsided, which can take weeks and leaves the fracture fragments displaced. We describe a novel protocol for the management of displaced intraarticular calcaneus fractures that utilises a temporising external fixator and staged conversion to plate fixation through a sinus tarsi approach. The goal of this technique was to enable earlier treatment with open reduction and internal fixation, minimise the amount of manipulation required at the time of definitive fixation and reduce the wound complication rate seen with the traditional extensile approach.

METHODS

The records of patients with displaced calcaneus fractures from 2010-2014 were reviewed retrospectively. A total of nine patients with 10 calcaneus fractures were treated using this protocol. All patients underwent ankle-spanning medial external fixation within 48 hours after injury. Patients underwent conversion to open plate fixation through a sinus tarsi approach when skin turgor had returned to normal. Time to surgery, infection rate, wound complications, radiographic alignment, and time to radiographic union were recorded.

RESULTS

The average Bohler's angle improved from 13.2 (range -2 to 34) degrees preoperatively to 34.3 (range 26 to 42) degrees postoperatively. The average time from external fixation to conversion to internal fixation was 4.8 (range 3 to 7) days. There were no immediate post-surgical complications. The average time to weight-bearing was 8.5 weeks. The average time to radiographic union was 9.5 (range 8 to 12) weeks. There were no infections or wound complications at the time of last follow-up.

CONCLUSION

Early temporising external fixation for the acute management of displaced calcaneus fractures is a safe and effective method to reduce and stabilise the foot and may decrease the time to definitive fixation. There were no complications related to the use of the external fixator in this series.

Mid-term outcomes in HIV-positive patients after primary total hip or knee arthroplasty

We hypothesized that infection rates following total joint arthroplasty (TJA) in those with the human immunodeficiency virus (HIV) without hemophilia or drug use would be similar to rates in HIV-negative patients. Records at an urban HIV referral hospital were searched for patients who underwent primary total hip and knee arthroplasty from 2003 to 2010. The primary outcome was revision for infection. 372 HIV-negative and 22 HIV-positive TJA patients met inclusion criteria. The HIV-positive group had more deep infections than the HIV-negative group (9.1% v 2.2%, P=0.102). There were no infections in those with AIDS-defining CD4 counts. Those with HIV may have a higher risk of developing a deep infection. A low CD4 count is not an absolute contraindication to TJA in HIV positive patients.

Comorbidities and perioperative complications in HIV-positive patients undergoing primary total hip and knee arthroplasty

BACKGROUND

Highly active antiretroviral therapy has prolonged the lifespan of individuals infected with human immunodeficiency virus (HIV). We hypothesized that the number of primary total joint arthroplasties performed in this population has been increasing and that HIV infection is not an independent risk factor for postoperative complications.

METHODS

The Nationwide Inpatient Sample for the years 2000 through 2008 was queried to identify patients who underwent primary total joint arthroplasty. HIV, comorbidities, and complications were identified with use of ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) codes. Data were analyzed with use of multivariate logistic regression, the Pearson chi-square test, and the Mann-Kendall trend test.

RESULTS

Of the estimated 5,681,024 admissions for primary total hip and knee arthroplasty in the United States during this period, 8229 (0.14%) were in patients who had HIV. Compared with HIV-negative patients (controls), infected patients were more likely to be younger, be male, and have a history of osteonecrosis, liver disease, drug use, and coagulopathy. The number of total hip and total knee arthroplasties in HIV-positive patients increased from 2000 to 2008 (p &lt; 0.05). Seventy-nine percent (6499) of the total joint arthroplasties in the HIV-positive patients involved the hip. Compared with HIV-negative patients undergoing total hip arthroplasty, HIV-positive patients were more likely to develop acute renal failure (1.3% compared with 0.8%, p = 0.04), develop a wound infection (0.6% compared with 0.3%, p = 0.02), and undergo postoperative irrigation and debridement (0.2% compared with 0.1%, p = 0.01). They were less likely to have a myocardial infarction (0.4% compared with 0.9%, p = 0.04). There was no difference in total complications (8.3% compared with 7.8%, p = 0.52). Similarly, there was no difference in total complications in patients undergoing total knee arthroplasty (7.8% compared with 8.0%, p = 0.76). HIV was not an independent risk factor for complications in total hip arthroplasty (odds ratio [OR], 1.18; 95% confidence interval [CI], 0.95 to 1.47) or total knee arthroplasty (OR, 0.78; 95% CI, 0.49 to 1.25).

CONCLUSIONS

The incidence of primary total joint arthroplasty in HIV-positive patients has been increasing. These patients were at slightly higher risk of certain immediate postoperative complications because of a higher rate of medical comorbidities. HIV infection was not an independent risk factor for the total rate of perioperative complications.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

n-ZnO/LaAlO3/p-Si heterojunction for visible-blind UV detection

A visible-blind UV photodetector (PD) using a double heterojunction of n-ZnO/LaAlO3 (LAO)/p-Si was demonstrated. Inserted LAO layers exhibit electrical insulating properties and serve as blocking layers for photoexcited electrons from p-Si to n-ZnO, leading to an enhanced rectification ratio and a visible-blind UV detectivity of the n-ZnO/LAO/p-Si PDs due to the high potential barrier between LAO and p-Si layers (~2.0 eV). These results support the use of n-ZnO/LAO/p-Si PDs in the visible-blind UV PDs in a visible-light environment.

Solar energy harvesting scheme using syringe-like ZnO nanorod arrays for InGaN/GaN multiple quantum well solar cells

Syringe-like ZnO nanorod arrays (NRAs) synthesized by a hydrothermal method were applied as the light-harvesting layer on InGaN-based multiple quantum well (MQW) solar cells. Theoretical calculations show that the NRAs with an abrupt shrinkage of tip diameter can further suppress surface reflectance in comparison with the flat NRAs. InGaN-based MQW solar cells with the syringe-like NRAs exhibit greatly improved conversion efficiencies by 36%. These results are attributed to the improved flatness of the refractive index profile at the air/device interface, which results in enhanced light trapping effect on the device surface.

Single fluorescent gold nanoclusters

Both ensemble and single-molecule measurements were performed to explore the fluorescence properties of Au nanoclusters (NCs). Photoinduced fluorescence enhancement was observed for ensemble NCs in solution, but photobleaching was found at ambient environments. At the single-molecule level, fluorescence blinking and single-step photobleaching were observed. Furthermore, their time-resolved fluorescence shows a single exponential decay with a lifetime of approximately 7 ns and is insensitive to changes in fluorescence intensity. The lifetime distribution is more homogeneous within ensemble Au NCs as compared to CdSe QDs. Therefore, Au NCs have potential applications as nontoxic fluorescent labels for lifetime-based imaging microscopy. However, their low quantum yields and poor photostability are disadvantageous factors, which require further improvement.

Effectiveness of workplace rehabilitation interventions in the treatment of work-related low back pain: A systematic review

PURPOSE

A systematic review was conducted to evaluate the effectiveness of workplace rehabilitation interventions for injured workers with low back pain (LBP).

METHOD

MEDLINE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), EMBASE, and AMED (Allied and Complementary Medicine) were searched from 1982 to 2005 for peer-reviewed studies of rehabilitation interventions that were provided at the workplace to workers with musculoskeletal work-related LBP. Methodological quality appraisal and data extraction were conducted by five reviewers.

RESULTS

Of a total of 1,224 articles that were identified by the search, 15 articles, consisting of 10 studies, were of sufficient quality to be included in the review. The best evidence was that clinical interventions with occupational interventions as well as early return to work/modified work interventions were effective in returning workers to work faster, reducing pain and disability, and decreasing the rate of back injuries. Ergonomic interventions also were found to be effective workplace interventions.

CONCLUSION

The need for further research in this area is necessary to reduce the burden of back pain on employees and their families, employers, and the health care system.

ZnO/Al2O3 core-shell nanorod arrays: growth, structural characterization, and luminescent properties

We report an aqueous chemical method to fabricate well-aligned ZnO/Al(2)O(3) nanocrystal (NC) core-shell nanorod arrays (NRAs). Structural characterization showed that the shell layers are composed of alpha-Al(2)O(3) nanocrystals. Photoluminescence measurements showed the enhancement of near-band-edge (NBE) emission of ZnO NRAs due to the presence of Al(2)O(3) NC shells. The Al(2)O(3) NC shell layer resulting in the flat-band effect near the ZnO surface leads to a stronger overlap of the wavefunctions of electrons and holes in the ZnO core, further enhancing the NBE emission. This approach should be very useful in designing many other core-shell NRAs for creating varieties of high-efficiency optoelectronic devices.

Improvement of conversion efficiency for multi-junction solar cells by incorporation of Au nanoclusters

We studied the photoluminescence (PL) and photovoltaic current-voltage characteristics of the three-junction InGaP/InGaAs/Ge solar cells by depositing Au nanoclusters on the cell surface. The increases of the PL intensity and short-circuit current after incorporation of Au nanoclusters are evident. An increase of 15.3% in energy conversion efficiency (from 19.6 to 22.6%) is obtained for the three-junction solar cells in which Au nanoclusters have been incorporated. We suggest that the increased light trapping due to radiative scattering from Au nanoclusters is responsible for improving the performance of the three-junction solar cells.

An energy-dense complementary food is associated with a modest increase in weight gain when compared with a fortified porridge in Malawian children aged 6-18 months

Poor complementary feeding practices are associated with stunting and growth faltering throughout the developing world. The objective was to compare the effect of using peanut-/soy-based fortified spread (FS) and corn porridge fortified with fish powder (FP) as complementary foods on growth in rural Malawian children. A total of 240 children were enrolled at the age of 6 mo and randomized to receive FS or FP. Both complementary foods provided 836 kJ/d from 6 to 9 mo of age and 1254 kJ/d from 9 to 18 mo of age. Children were followed monthly for anthropometry and fortnightly for the symptoms of fever, cough, or diarrhea until they were 18 mo old. Zn and Se status were assessed at 6 and 12 mo. The primary outcomes were the rates of weight and length gain from 6-12 mo and from 12-18 mo. Children who received FS gained 110 g more (95% CI 220 to 10) from 6-12 mo of age than children receiving FP. Weight gain did not differ between children receiving FS and FP between 12 and 18 mo of age, nor did statural growth from 6 to 12 mo or 12 to 18 mo. A total of 23% of all children were Zn deficient at 6 mo of age and this increased to 37% at 12 mo of age. Neither FS nor FP was associated with significantly improved Zn status. FS was associated with better weight gain from 6-12 mo of age and may be useful in conjunction with additional interventions to improve infant growth in the developing world.

A prospective assessment of food and nutrient intake in a population of Malawian children at risk for kwashiorkor

OBJECTIVE

To determine what foods, nutrients, and dietary patterns are associated with development of kwashiorkor in populations of vulnerable 1- to 3-year-old Malawian children.

PATIENTS AND METHODS

This was a prospective observational study conducted in 8 rural villages. Upon enrollment, demographic, anthropometric, and dietary intake data were collected. Children were studied every 2 weeks for 10 weeks to determine whether they developed kwashiorkor. Dietary intake was assessed on enrollment using a food frequency questionnaire, which included all possible foods in the child's diet. Food frequency data were used to estimate energy, protein, vitamins C and A, niacin, thiamin, zinc, and iron intake using food composition and serving size data. Dietary diversity was assessed with a 7-point score. Regression modeling was used to determine whether the consumption of any food or nutrient was associated with the development of kwashiorkor.

RESULTS

A total of 43 (2.6%) of the 1651 healthy children ages 1 to 3 years enrolled developed kwashiorkor. Children who developed kwashiorkor were younger and had more nutritional wasting than those who did not. Thirty children (70%) who developed kwashiorkor were breast-fed. In the combined regression model no foods or nutrients were found to be associated with the development of kwashiorkor. There were no differences in the dietary diversity between children who developed kwashiorkor and those who did not.

CONCLUSIONS

No association between the development of kwashiorkor and the consumption of any food or nutrient was found.

Effect of air pollution on pediatric respiratory emergency room visits and hospital admissions

In order to assess the effect of air pollution on pediatric respiratory morbidity, we carried out a time series study using daily levels of PM10, SO2, NO2, ozone, and CO and daily numbers of pediatric respiratory emergency room visits and hospital admissions at the Children's Institute of the University of Sao Paulo Medical School, from August 1996 to August 1997. In this period there were 43,635 hospital emergency room visits, 4534 of which were due to lower respiratory tract disease. The total number of hospital admissions was 6785, 1021 of which were due to lower respiratory tract infectious and/or obstructive diseases. The three health end-points under investigation were the daily number of emergency room visits due to lower respiratory tract diseases, hospital admissions due to pneumonia, and hospital admissions due to asthma or bronchiolitis. Generalized additive Poisson regression models were fitted, controlling for smooth functions of time, temperature and humidity, and an indicator of weekdays. NO2 was positively associated with all outcomes. Interquartile range increases (65.04 microg/m3) in NO2 moving averages were associated with an 18.4% increase (95% confidence interval, 95% CI = 12.5-24.3) in emergency room visits due to lower respiratory tract diseases (4-day moving average), a 17.6% increase (95% CI = 3.3-32.7) in hospital admissions due to pneumonia or bronchopneumonia (3-day moving average), and a 31.4% increase (95% CI = 7.2-55.7) in hospital admissions due to asthma or bronchiolitis (2-day moving average). The study showed that air pollution considerably affects children's respiratory morbidity, deserving attention from the health authorities.

Air pollution and neonatal deaths in São Paulo, Brazil

Air pollution has been associated with health effects on different age groups. The present study was designed to assess the impact of daily changes in air pollutants (NO2, SO2, CO, O3, and particle matter (PM10)) on total number of daily neonatal deaths (those that occur between the first and the 28th days of life) in São Paulo, from January 1998 to December 2000, since adverse outcomes such as neonatal deaths associated with air pollution in Brazil have not been evaluated before. Generalized additive Poisson regression models were used and nonparametric smooth functions (loess) were adopted to control long-term trend, temperature, humidity, and short-term trends. A linear term was used for holidays. The association between air pollutants and neonatal deaths showed a short time lag. Interquartile range increases in PM10 (23.3 microg/m(3)) and SO2 (9.2 microg/m(3)) were associated with increases of 4% (95% CI, 2-6) and 6% (95% CI, 4-8), respectively. Instead of adopting a two-pollutant model we created an index to represent PM10 and SO2 effects. For an interquartile range increase in the index an increase of 6.3% (95% CI, 6.1-6.5) in neonatal deaths was observed. These results agree with previous studies performed by our group showing the deleterious effects of air pollutants during the perinatal period. The method reported here represents an alternative approach to analyze the relationship between highly correlated pollutants and public health problems, reinforcing the idea of the synergic effects of air pollutants in public health.

Health effects of air pollution exposure on children and adolescents in São Paulo, Brazil

Children and adolescents have been considered more susceptible to the effects of air pollution than adults. In order to investigate the responses of children of different ages to air pollution exposure, daily records of hospital admissions for children in five age groups (equal or less than 2 years of age, 3-5, 6-13, 14-19, and all ages together, i.e., from 0-19 years of age) were obtained from January 1993 to November 1997 in São Paulo, Brazil, and were compared to daily records of PM10, O3, SO2, CO and NO2 concentrations in ambient air. For each age group a generalized additive Poisson regression was fitted controlling for smooth functions of time, temperature, humidity, and days of the week, with an additional indicator for holidays. Polynomial distributed lag models were used to estimate the 7-day cumulative effect of each pollutant. Children 2 years or less were the most susceptible to the effects of all five pollutants with an increase of 9.4% (95% CI: 7.9,10.9) in respiratory admissions associated with each interquartile range increase in PM10. The oldest group was the second most susceptible to air pollutants, with each interquartile range increase in PM10 associated with a 5.1% (95% CI: 0.3,9.8) increase in respiratory admissions. An interquartile range increase in CO was associated with an 11.3% (95% CI: 5.9,16.8) increase in respiratory hospitalizations. When a multipollutant model was used, the effect of PM10 on respiratory admissions for all ages together was unchanged, while the SO2 and the other pollutants effect was substantially reduced. This study showed that daily respiratory hospital admissions for children and adolescents in São Paulo increased with air pollution, and that the largest effects were found for the youngest (2 years or less) and oldest (14-19 years) age groups.

Health effects of air pollution exposure on children and adolescents in São Paulo, Brazil

Children and adolescents have been considered more susceptible to the effects of air pollution than adults. In order to investigate the responses of children of different ages to air pollution exposure, daily records of hospital admissions for children in five age groups (equal or less than 2 years of age, 3-5, 6-13, 14-19, and all ages together, i.e., from 0-19 years of age) were obtained from January 1993 to November 1997 in São Paulo, Brazil, and were compared to daily records of PM10, O3, SO2, CO and NO2 concentrations in ambient air. For each age group a generalized additive Poisson regression was fitted controlling for smooth functions of time, temperature, humidity, and days of the week, with an additional indicator for holidays. Polynomial distributed lag models were used to estimate the 7-day cumulative effect of each pollutant. Children 2 years or less were the most susceptible to the effects of all five pollutants with an increase of 9.4% (95% CI: 7.9,10.9) in respiratory admissions associated with each interquartile range increase in PM10. The oldest group was the second most susceptible to air pollutants, with each interquartile range increase in PM10 associated with a 5.1% (95% CI: 0.3,9.8) increase in respiratory admissions. An interquartile range increase in CO was associated with an 11.3% (95% CI: 5.9,16.8) increase in respiratory hospitalizations. When a multipollutant model was used, the effect of PM10 on respiratory admissions for all ages together was unchanged, while the SO2 and the other pollutants effect was substantially reduced. This study showed that daily respiratory hospital admissions for children and adolescents in São Paulo increased with air pollution, and that the largest effects were found for the youngest (2 years or less) and oldest (14-19 years) age groups.

Environmental epidemiology applied to urban atmospheric pollution: a contribution from the Experimental Air Pollution Laboratory (LPAE)

Systematic investigation on the effects of human exposure to environmental pollution using scientific methodology only began in the 20th century as a consequence of several environmental accidents followed by an unexpected mortality increase above expected mortality and as a result of observational epidemiological and toxicological studies conducted on animals in developed countries. This article reports the experience of the Experimental Air Pollution Laboratory at the School of Medicine, University of São Paulo, concerning the respiratory system and pathophysiological mechanisms involved in responses to exposure to pollution using toxicological and experimental procedures, complemented by observational epidemiological studies conducted in the city of São Paulo. It also describes these epidemiological studies, pointing out that air pollution is harmful to public health, not only among susceptible groups but also in the general population, even when the concentration of pollutants is below the limits set by environmental legislation. The study provides valuable information to support the political and economic decision-making processes aimed at preserving the environment and enhancing quality of life.

[Transposition of muscular skeletal flap pedicled with straight head of rectus femoris for treatment of avascular necrosis of femoral head]

OBJECTIVE

To investigate the clinical results of transposition of muscular skeletal flap pedicled with straight head of rectus femoris for treatment of avascular necrosis of adult femoral head.

METHODS

Eight patients with avascular necrosis of femoral head were adopted in this study. There were 6 males and 2 females, the ages were ranged from 24 to 56 years. According to the criteria of Ficat, there were 5 cases in stage II and 3 cases in stage III. The Smith-Peterson incision was used to expose the capsule of the hip. After complete curettage of the necrotic bone from the femoral head, the muscular skeletal flap pedicled with straight head of rectus femoris was resected and transposited into femoral head. Finally, conventional decompression of head was performed.

RESULTS

All the cases were followed up for 1 to 3 years. There were excellent results in 5 cases, good in 2 cases and moderate in 1 case. The rate of excellent and good results were 87.5%.

CONCLUSION

Comparing with other pedicled bony flaps, the muscular skeletal flap pedicled with straight head of rectus femoris is characterized by its convenience and efficacy. It is suitable for the treatment of avascular necrosis of femoral head in stage II or III, but the contour of the femoral head should be nearly normal.

Air pollution and respiratory illness of children in São Paulo, Brazil

This investigation reports the association between air pollution and paediatric respiratory emergency visits in São Paulo, Brazil, the largest city in South America. Daily records of emergency visits were obtained from the Children's Institute of the University of São Paulo for the period from May 1991 to April 1993. Visits were classified as respiratory and non-respiratory causes. Respiratory visits were further divided into three categories: upper respiratory illness, lower respiratory illness and wheezing. Daily records of SO2, CO, particulate matter (PM10), O3 and NO2 concentrations were obtained from the State Air Pollution Controlling Agency of São Paulo. Associations between respiratory emergency visits and air pollution were assessed by simple comparative statistics, simple correlation analysis and by estimating a variety of regression models. Significant associations between the increase of respiratory emergency visits and air pollution were observed. The most robust associations were observed with PM10, and to a lesser extent with O3. These associations were stable across different model specifications and several controlling variables. A significant increase in the counts of respiratory emergency visits--more than 20%--was observed on the most polluted days, indicating that air pollution is a substantial paediatric health concern in São Paulo.

Air pollution and respiratory illness of children in São Paulo, Brazil

This investigation reports the association between air pollution and paediatric respiratory emergency visits in São Paulo, Brazil, the largest city in South America. Daily records of emergency visits were obtained from the Children's Institute of the University of São Paulo for the period from May 1991 to April 1993. Visits were classified as respiratory and non-respiratory causes. Respiratory visits were further divided into three categories: upper respiratory illness, lower respiratory illness and wheezing. Daily records of SO2, CO, particulate matter (PM10), O3 and NO2 concentrations were obtained from the State Air Pollution Controlling Agency of São Paulo. Associations between respiratory emergency visits and air pollution were assessed by simple comparative statistics, simple correlation analysis and by estimating a variety of regression models. Significant associations between the increase of respiratory emergency visits and air pollution were observed. The most robust associations were observed with PM10, and to a lesser extent with O3. These associations were stable across different model specifications and several controlling variables. A significant increase in the counts of respiratory emergency visits--more than 20%--was observed on the most polluted days, indicating that air pollution is a substantial paediatric health concern in São Paulo.

Respiratory system mechanics in guinea pigs after acute hemorrhage: role of adrenergic stimulation

We evaluated the effects of acute blood loss on the respiratory mechanics of guinea pigs. We measured respiratory system elastance (Ers) and resistance (Rrsmax) using the end-inflation occlusion method. Rrsmax was partitioned into its homogeneous component (Rrsmin) and that due to the unevenness within the respiratory system (Rrsu). Respiratory mechanics were studied both before and immediately after bleeding in eight animals. Another eight guinea pigs had received propranolol previously and were also submitted to hemorrhage. Propranolol-treated animals showed higher control values of Rrsmax (p less than .02) and Rrsmin (p less than .0001). Animals not treated with propranolol exhibited a decrease (p less than 0.001) in Rrsmax after hemorrhagic hypovolemia (from 0.375 +/- 0.051 to 0.323 +/- 0.042 cm H2O/ml.sec), due to a decrease (p less than 0.005) in Rrsmin (from 0.140 +/- 0.031 to 0.094 +/- 0.032 cm H2O/ml.sec), whereas Ers and Rrsu did not change. Propranolol-treated animals showed an increase (p less than .001) in Rrsmax (from 0.512 +/- 0.133 to 0.664 +/- 0.144 cm H2O/ml.sec), Rrsu (p less than 0.01) from 0.252 +/- 0.09 to 0.345 +/- 0.139 cm H2O/ml.sec, and Ers (p less than 0.001) (from 4.565 +/- 0.933 to 5.402 +/- 1.24 cm H2O/ml) after bleeding. The results indicate that the immediate effects of acute bleeding on respiratory mechanics are significantly influenced by catecholamines.

Hypovolemic shock resuscitation with hyperosmotic 7.5% NaCl: effects on respiratory system mechanics

The infusion of the hypertonic 7.5% NaCl solution stimulates the afferent vagal innervation of the lungs. In order to verify if this reflex elicits any respiratory mechanical alterations, normovolemic (n = 18) and hypovolemic (n = 18) (20 ml of shed blood/kg) guinea pigs were studied. The animals were assigned to groups of nine receiving either isotonic 0.9% NaCl or hypertonic 7.5% NaCl solutions (4 ml/kg body weight). Passive respiratory system elastance (Ers) and the maximal value of the resistance (Rrsmax) were measured. The latter was further partitioned into its minimal value (Rrsu) using the constant flow inflation method. Ers, Rrsmax, Rrsmin, and Rrsu were measured before and at 0, 2, 5, 10, and 15 minutes following the infusion. The results showed that both isotonic and hypertonic solutions, at the given volume rate, caused no significant alterations of respiratory mechanics in normovolemic and hypovolemic animals.