An Endovascular- Versus a Surgery-First Revascularization Strategy for Chronic Limb-Threatening Ischemia: A Meta-Analysis of Randomized Controlled Trials.

Timely revascularization is essential for limb salvage and to reduce mortality in patients with chronic limb-threatening ischemia (CLTI). In patients who are candidates for endovascular therapy and surgical bypass, the optimal revascularization strategy remains uncertain. Recently published randomized controlled trials (RCTs) have presented conflicting results. We conducted a trial-level meta-analysis to compare the outcomes between endovascular-first and surgery-first strategies for revascularization. PubMed, Web of Science, and the Cochrane Library were searched to identify RCTs comparing the outcomes of endovascular-first versus surgery-first strategies for revascularization in patients with CLTI. Data were pooled for major outcomes and their aggregate risk ratios (RRs) with 95% confidence intervals were calculated using a random-effects model. Kaplan-Meier curves for amputation-free survival and overall survival time were plotted using the pooled aggregated data from published curves, with their corresponding hazard ratios (HRs) and 95% confidence intervals reported for up to 5 years of follow-up. A total of 3 RCTs with 2,627 patients (1,312 endovascular-first and 1,315 surgery-first) were included in the meta-analysis. Of these, 1,864 patients (70.9%) were men and 347 (13.2%) were older than 80 years. Comparing the endovascular-first and surgery-first approaches, there was no significant difference in the overall (HR 0.92 [0.83 to 1.01], p = 0.09) or amputation-free survival (HR 0.98 [0.92 to 1.03], p = 0.42), reintervention (RR 1.24 [0.74 to 2.07], p = 0.41), major amputation, (RR 1.16 [0.87 to 1.54], p = 0.31), or therapeutic crossover (RR 0.92 [0.37 to 2.26], p = 0.85). In conclusion, data from available RCTs suggest that there is no difference in clinical outcomes between endovascular-first and surgery-first revascularization strategies for CLTI. A planned patient-level meta-analysis may provide further insight.

Pericardial effusion in an immunocompetent host- a unique presentation of histoplasmosis.

Histoplasma capsulatum infection is infrequently considered in the differential diagnoses for acute pericarditis in immunocompetent hosts when presenting with tamponade physiology, given its gradual infective nature. We describe a case of a young male presenting solely with acute pericarditis with pericardial effusion and early cardiac tamponade physiology secondary to a pulmonary histoplasmosis infection. Our patient had no pulmonary symptoms; the only pulmonary manifestation of histoplasmosis included incidental findings of subcarinal lymphadenopathy and a left lingular nodule abutting the pericardium. Given failure of symptom improvement with pericardiocentesis and first-line therapy for idiopathic/viral pericarditis, further workup of the pulmonary nodule was pursued. Histopathologic analysis of tissue showed caseating granulomas and fungal Grocott-Gömöri's methenamine silver stain revealed yeast consistent with Histoplasma species. The patient improved with itraconazole therapy. Learning objective: Pulmonary histoplasmosis has potential to present as a pericardial effusion in the immunocompetent individual. In addition to pericardiocentesis, antifungal therapy can be curative.

Regulation of Hypoxic-Adenosinergic Signaling by Estrogen: Implications for Microvascular Injury.

Loss of estrogen, as occurs with normal aging, leads to increased inflammation, pathologic angiogenesis, impaired mitochondrial function, and microvascular disease. While the influence of estrogens on purinergic pathways is largely unknown, extracellular adenosine, generated at high levels by CD39 and CD73, is known to be anti-inflammatory in the vasculature. To further define the cellular mechanisms necessary for vascular protection, we investigated how estrogen modulates hypoxic-adenosinergic vascular signaling responses and angiogenesis. Expression of estrogen receptors, purinergic mediators inclusive of adenosine, adenosine deaminase (ADA), and ATP were measured in human endothelial cells. Standard tube formation and wound healing assays were performed to assess angiogenesis in vitro. The impacts on purinergic responses in vivo were modeled using cardiac tissue from ovariectomized mice. CD39 and estrogen receptor alpha (ERα) levels were markedly increased in presence of estradiol (E2). Suppression of ERα resulted in decreased CD39 expression. Expression of ENT1 was decreased in an ER-dependent manner. Extracellular ATP and ADA activity levels decreased following E2 exposure while levels of adenosine increased. Phosphorylation of ERK1/2 increased following E2 treatment and was attenuated by blocking adenosine receptor (AR) and ER activity. Estradiol boosted angiogenesis, while inhibition of estrogen decreased tube formation in vitro. Expression of CD39 and phospho-ERK1/2 decreased in cardiac tissues from ovariectomized mice, whereas ENT1 expression increased with expected decreases in blood adenosine levels. Estradiol-induced upregulation of CD39 substantially increases adenosine availability, while augmenting vascular protective signaling responses. Control of CD39 by ERα follows on transcriptional regulation. These data suggest novel therapeutic avenues to explore in the amelioration of post-menopausal cardiovascular disease, by modulation of adenosinergic mechanisms.

Geometric Indices for Predicting Ischemic Mitral Regurgitation: Correlation of Mitral Valve Coaptation Area With Tenting Height, Tenting Area and Tenting Volume.

OBJECTIVES: Ischemic remodeling of the left ventricle in patients with coronary artery disease (CAD) results in geometric changes of the mitral valve (MV) apparatus, leading to reduced MV leaflet coaptation. Although the calculation of the coaptation area has value in assessing the effects of left ventricular remodeling on the MV, it is difficult and time-consuming to measure. In this study the authors hypothesized that the tenting volume (TV) would have a greater association with coaptation area than tenting height (TH) or tenting area (TA). DESIGN: A retrospective review. SETTING: A single tertiary-care academic hospital. PARTICIPANTS: There were 145 adult patients who underwent coronary artery bypass graft surgery between April 2018 and July 2020. MEASUREMENTS AND MAIN RESULTS: Intraoperative 2- and 3-dimensional transesophageal echocardiographic studies were obtained in the precardiopulmonary bypass period. Offline analysis was used to obtain TH, TA, TV and coaptation area for each patient. Correlation between the coaptation area and the TH, TA, and TV was conducted using Pearson's correlation. The median age of the population was 68.0 years (61.0-73.3), the body mass index was 29.0 kg/m2 (25.7-33.5), and 17.8% were females. Increases in TV were the most reliable predictor of decreases in coaptation area (R2 = 0.75) followed by TA (R2 = 0.48) and TH (R2 = 0.47). CONCLUSION: As a representative of the complete topography of the MV, the authors' study demonstrated that in patients with CAD, TV has a greater negative correlation with coaptation area as compared to TH or TA.

A systematic review and meta-analysis of general versus regional anesthesia for lower extremity amputation.

OBJECTIVE: Postoperative morbidity in patients undergoing lower extremity amputation (LEA) has remained high. Studies investigating the influence of the anesthetic modality on the postoperative outcomes have yielded conflicting results. The aim of our study was to assess the effects of regional anesthesia vs general anesthesia on postoperative complications for patients undergoing LEA. METHODS: We systematically searched PubMed, Embase, MEDLINE, Web of Science, and Google Scholar from 1990 to 2022 for studies investigating the effect of the anesthetic modality on the postoperative outcomes after LEA. Regional anesthesia (RA) included neuraxial anesthesia and peripheral nerve blocks. The outcomes included 30-day mortality, respiratory failure (unplanned postoperative intubation, failure to wean, mechanical ventilation >24 hours), surgical site infection, cardiac complications, urinary tract infection, renal failure, sepsis, venous thrombosis, pneumonia, and myocardial infarction. RESULTS: Of the 25 studies identified, we included 10 retrospective observational studies with 81,736 patients, of whom 69,754 (85.3%) had received general anesthesia (GA) and 11,980 (14.7%) had received RA. In the GA group, 50,468 patients were men (63.8%), and in the RA group, 7813 patients were men (62.3%). The results of the meta-analyses revealed that GA was associated with a higher rate of respiratory failure (odds ratio, 1.38; 95% confidence interval, 1.06-1.80; P = .02) and sepsis (odds ratio, 1.21; 95% confidence interval, 1.11-1.33; P < .0001) compared with RA. No differences were found in postoperative 30-day mortality, surgical site infection, cardiac complications, urinary tract infection, renal failure, venous thrombosis, pneumonia, and myocardial infarction between the GA and RA groups. CONCLUSIONS: The results of our meta-analysis have shown that GA could be associated with a higher rate of respiratory failure and sepsis compared with RA for LEA.

Timing of Blood Transfusions and 30-Day Patient Outcomes After Coronary Artery Bypass Graft Surgery.

OBJECTIVE: Packed red blood cell transfusion during coronary artery bypass graft surgery is known to be associated with adverse outcomes. However, the association of the timing between transfusions in relation to discharge and 30-day postoperative outcomes has not been studied. The study authors investigated the impact of transfusion timing on 30-day surgical outcomes. DESIGN: A retrospective review. SETTING: At a single tertiary-care academic hospital. PARTICIPANTS: A total of 2,481 adult patients underwent primary coronary artery bypass graft surgery between January 2014 and December 2020. MEASUREMENTS AND MAIN RESULTS: The relationship between the timing of packed red blood cell transfusion (intraoperative, postoperative, or both) and 30-day postoperative outcome variables was calculated as an odds ratio. The influence of timing of transfusion on adjusted probability of postoperative complications was plotted against the lowest intraoperative hematocrit. The median age of the population was 67 years (60.0-74.0), body mass index was 28.5 (25.6-32.3) kg/m2, and 497 (20.0%) were female. A total of 1,588 (36%) patients received packed red blood cell transfusions; 182 (7.3%) received intraoperative transfusions, 489 (19.7%) received postoperative transfusions, and 222 (9.0%) received both (intraoperative and postoperative transfusions). Postoperative transfusion was associated with significantly higher odds of readmission (1.83 [1.32-2.54], p = 0.002) and heart failure (1.64 [1.2-2.23], p = 0.008) compared to patients with no transfusions; whereas intraoperative transfusions were not. CONCLUSION: The authors' data suggested that the postoperative timing of transfusion in patients undergoing coronary artery bypass graft surgery may be associated with an increased incidence of 30-day heart failure and readmission. Prospective research is needed to conclusively confirm these findings.

Open Abdominal Aortic Aneurysm Surgery and Renal Dysfunction; Association of Demographic and Clinical Variables with Proximal Clamp Location.

BACKGROUND: While cross-clamp site is a known risk factor for postoperative acute and chronic renal dysfunction following open abdominal aortic aneurysm surgery (AAA), the additive impact of patient demographic and clinical factors is lacking. In this study, we investigated the impact of body mass index (BMI), surgical duration and aneurysm diameter on the association between proximal cross-clamp location and postoperative renal dysfunction. METHODS: In this study, we conducted a retrospective analysis of 4,197 patients undergoing open AAA surgery between 2011 and 2018 using data housed in the American College of Surgeons National Safety Quality Improvement Program (ACS-NSQIP) database. The primary outcome was renal dysfunction, which was defined as patients requiring dialysis within 30 days or patients with ≥2 mg/dL rise in creatinine from baseline. We assessed the incidence of renal dysfunction with regard to clamp location and subsequently used multivariable logistic regression to assess clinical and demographic factors associated with renal dysfunction. We used a regression model to plot the association of BMI, surgical duration, and aneurysm diameter with an adjusted probability of postoperative acute and chronic renal dysfunction for individual cross-clamp locations. RESULTS: Of the 4,197 patients analyzed, 405 patients (9.6%) developed renal dysfunction within 30 days with 287 patients requiring dialysis. Patients with supraceliac clamp location had the highest incidence of renal dysfunction (20.4%). Our data showed a significant association of renal dysfunction with higher BMI patients [OR 1.04 (1.02, 1.07), P = 0.001], longer operative times [OR1.01 (1.01, 1.02), P < 0.001], clamp location between the superior mesenteric artery (SMA) and renal artery [OR 1.80 (1.17, 2.78), P = 0.007] and supraceliac clamp location [OR 2.47 (1.62, 3.76), P < 0.001]. CONCLUSIONS: The incidence of renal dysfunction increases with suprarenal clamps. Patients with higher BMI, longer operative times, and increasing aneurysm diameter, and a suprarenal clamp have a significantly increased risk of renal dysfunction compared to those who also had a suprarenal clamp but lower BMI, shorter operative times and smaller aneurysm diameter.

Three-Dimensional Transesophageal Echocardiography Simulator: New Learning Tool for Advanced Imaging Techniques.

The use of intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) has grown exponentially in recent years. Three-dimensional TEE technology has evolved to allow for real-time display of 3D images and, thus, has become the standard of care for the evaluation of cardiac anatomy and function. Its use has provided a new dimension of clinical insight when managing patients for cardiac surgery or structural heart interventions. While the intraoperative utility of 3D TEE has expanded, there has been a slower advancement in the area of training and, specifically, simulator-based training in 3D TEE. This training is essential, as the skill set involved in acquiring 3D data sets differs from that of two-dimensional (2D) TEE and requires users to be able to appreciate how 3D anatomic display differs from that of tomographic cross-sectional 2D imaging. This added skill set requires mental reconstruction and spatial reorientation to appreciate the added elevational dimension in frustum-based imaging and is best achieved in a simulation environment rather than the busy operating room. In this review article, the authors evaluate the functionality of a 3D TEE simulator and how simulators such as this can establish preclinical proficiency in novices in the expanding area of advanced 3D TEE imaging.

Update: Gender differences in CABG outcomes-Have we bridged the gap?

BACKGROUND: Appreciation of unique presentation, patterns and underlying pathophysiology of coronary artery disease in women has driven gender based risk stratification and risk reduction efforts over the last decade. Data regarding whether these advances have resulted in unequivocal improvements in outcomes of CABG in women is conflicting. The objective of our study was to assess gender differences in post-operative outcomes following CABG. METHODS: Retrospective analyses of institutional data housed in the Society of Thoracic Surgeons (STS) database for patients undergoing CABG between 2002 and 2020 were conducted. Multivariable regression analysis was conducted to investigate gender differences in post-operative outcomes. P-values were adjusted using Bonferroni correction to reduce type-I errors. RESULTS: Our final cohort of 6,250 patients had fewer women than men (1,339 vs. 4,911). more women were diabetic (52.0% vs. 41.2%, p<0.001) and hypertensive (89.1% vs. 84.0%, p<0.001). Women had higher adjusted odds of developing ventilator dependence >48 hours (OR: 1.65 [1.21, 2.45], p = 0.002) and cardiac readmissions (OR: 1.56 [1.27, 2.30], p = 0.003). After adjustment for comorbidity burden, mortality rates in women were comparable to those of age-matched men. CONCLUSION: The findings of our study indicate that despite apparent reduction of differences in mortality, the burden of postoperative morbidity is still high among women.

Regional Anaesthesia for Lower Extremity Amputation is Associated with Reduced Post-operative Complications Compared with General Anaesthesia.

OBJECTIVE: Primary and secondary lower extremity amputation, performed for patients with lower extremity arterial disease, is associated with increased post-operative morbidity. The aim of the study was to assess the impact of regional anaesthesia vs. general anaesthesia on post-operative pulmonary complications. METHODS: A retrospective analysis of 45 492 patients undergoing lower extremity amputation between 2005 and 2018 was conducted using data from the American College of Surgeons National Safety Quality Improvement Program database. Multivariable logistic regression was carried out to assess differences in primary outcome of post-operative pulmonary complications (pneumonia or respiratory failure requiring re-intubation) within 48 hours and 30 days after surgery between patients receiving regional (RA) or general anaesthesia (GA). Secondary outcomes included post-operative blood transfusion, septic shock, re-operation, and post-operative death within 30 days. RESULTS: Of 45 492 patients, 40 026 (88.0%) received GA and 5 466 (12.0%) RA. Patients who received GA had higher odds of developing pulmonary complications at 48 hours (2.1% vs. 1.4%; adjusted odds ratio [aOR] 1.39, 95% confidence interval [CI] 1.09 - 1.78; p = .007) and within 30 days (6.3% vs. 5.9%; aOR 1.15, 95% CI 1.09 - 1.78; p = .039). The odds of blood transfusions (aOR 1.11, 95% CI 1.02 - 1.21; p = .017), septic shock (aOR 1.29, 95% CI 1.03 - 1.60; p = .025) and re-operation (OR 1.26, 95% CI 1.03 - 1.53; p = .023) were also higher for patients who received GA vs. patients who received RA. No difference in mortality rate was observed between patients who received GA and those who received RA (5.7% vs. 7.1%; odds ratio 0.95, 95% CI 0.84 - 1.07). CONCLUSION: A statistically significant reduction in pulmonary complications was observed in patients who received RA for lower extremity amputation compared with GA.

Enhanced Post-Operative Recovery with Continuous Peripheral Nerve Block After Lower Extremity Amputation.

BACKGROUND: Despite progress in perioperative care standards, there has not been a significant risk reduction in morbidity and mortality rates of lower extremity amputations, an intermediate risk surgery performed on high risk patients. The single-shot peripheral nerve block has shown equivocal impact on postoperative course following lower extremity amputation. Hence, we assessed the potential of preemptive use of continuous catheter-based peripheral nerve block in lower extremity amputations for reduction in pulmonary complications, acute post-operative pain scores, and opioid use in post-operative period. METHODS: A retrospective review of a quality improvement project initiated in 2018 was conducted to compare outcomes amongst general anesthesia in combination with a catheter-based peripheral nerve block (catheter group) and general anesthesia alone in patients receiving lower extremity amputation. The rate of postoperative pulmonary complications was identified as a primary endpoint. The secondary outcomes assessed were acute post-operative pain scores and opioid consumption up to 48 hours. Our analysis was adjusted for potential confounding variables inclusive of demographics, medical comorbidities, type of surgical procedure and smoking status. RESULTS: Ninety-six patients were included in the study (61 in the general anesthesia group, 35 in the catheter group). After adjusting for baseline demographics, comorbidities, surgical technique and smoking status, the odds of postoperative pulmonary complications were significantly lower with catheter-based peripheral nerve block in comparison to general anesthesia alone, OR 0.11 [95% CI, 0.01- 0.88] (P = 0.048). The decrease in acute pain scores was also observed in the catheter group when compared to general anesthesia alone, OR 0.72 [95% CI, 0.56 - 0.93] (P = 0.012). Similarly, the opioid consumption was also lower in the catheter group in comparison to general anesthesia alone, OR 0.97 [95% CI, 0.95 - 0.99] (P = 0.025). CONCLUSION: Preemptive use of continuous peripheral nerve block in patients undergoing lower extremity amputation reduces the incidence of pulmonary complications, acute postoperative pain scores and narcotic use in post-operative period.

Outcomes of total hip arthroplasty using dual-mobility cups for femoral neck fractures: a systematic review and meta-analysis.

OBJECTIVES: Femoral neck fractures (FNFs), with up to 15% mortality, are prominent orthopaedic emergencies. After treating FNFs, dislocation is another challenge increasing morbidity, mortality and treatment costs substantially. The emerging dual-mobility cup (DMC) may decrease dislocation rates following total hip arthroplasty (THA) for FNFs. We performed a systematic review of literature reporting dislocation and mortality rates with DMC-THA for the treatment of FNFs. METHODS: 2 authors independently searched PubMed (MEDLINE), Google Scholar and Cochrane library for studies reporting dislocation and mortality rates for FNFs treated with DMC-THA since inception up to January 2019. Data on outcomes of interest was extracted from all studies and assessed for eligibility for a meta-analysis. RESULTS: Out of 522 search results, 18 studies were included in the systematic review and 4 in the meta-analysis. The mean rate of dislocation following DMC-THA for FNFs was found to be 1.87% ± 2.11, with a 1-year mortality rate of 14.0% ± 10.55. Results of meta-analysis showed that dislocation and 1-year postoperative mortality rates were significantly lower for DMC-THA with a risk ratio 0.31 (95% CI, 0.16-0.59; I2 = 0%, p = 0.0003) and 0.55 (0.40, 0.77; I2 = 0%, p = 0.003) respectively when compared to biploar hemiathroplasty (BHA). CONCLUSIONS: The mean dislocation and mortality rates in DMC-THA are lower than previously reported rates for THA with single cup and comparable to unipolar and bipolar hemiarthroplasty. Further research involving randomised control trials to assess differences in outcomes, longevity and cost-effectiveness needs to be conducted to make recommendations for the use of DMC in treating FNFs.

Mobile phones in the orthopedic operating room: Microbial colonization and antimicrobial resistance.

BACKGROUND: Surgical site infections are a major cause of morbidity and mortality following orthopedic surgery. Recent efforts to identify sources of contamination in the operating rooms have implicated mobile phones. AIM: To investigate microbial colonization on the mobile phones of health care professionals in the orthopedic operating room. METHODS: We conducted a cross-sectional study involving culture and sensitivity analysis of swabs taken from the mobile phones of orthopedic and anesthesia attendings, residents, technicians and nurses working in the orthopedic operating rooms over a period of two months. Demographic and cell phone related factors were recorded using a questionnaire and the factors associated with contamination were analyzed. RESULTS: Ninety-three of 100 mobile phones were contaminated. Species isolated were Coagulase-negative Staphylococcus (62%), Micrococcus (41%) and Bacillus (26%). The risk of contamination was increased with mobile covers and cracked screens and decreased by cell phone cleaning. CONCLUSION: Mobile phones belonging to health care workers are frequently contaminated with pathogenic bacteria with the potential of transferring drug resistance to nosocomial pathogens. Studies investigating the relationship to surgical site infections need to be conducted. The concept of "mobile hygiene" involving the change of mobile covers, replacement of cracked screens or even wiping the phone with an alcohol swab could yield the cost-effective balance that contaminated cell phones deserve until they are established as a direct cause of surgical site infections.

Effect of hospital volume on outcomes of total hip arthroplasty: a systematic review and meta-analysis.

BACKGROUND: A shift in the healthcare system towards the centralization of common yet costly surgeries, such as total hip arthroplasty (THA), to high-volume centers of excellence, is an attempt to control the economic burden while simultaneously enhancing patient outcomes. The "volume-outcome" relationship suggests that hospitals performing more treatment of a given type exhibit better outcomes than hospitals performing fewer. This theory has surfaced as an important factor in determining patient outcomes following THA. We performed a systematic review with meta-analyses to review the available evidence on the impact of hospital volume on outcomes of THA. MATERIALS AND METHODS: We conducted a review of PubMed (MEDLINE), OVID MEDLINE, Google Scholar, and Cochrane library of studies reporting the impact of hospital volume on THA. The studies were evaluated as per the inclusion and exclusion criteria. A total of 44 studies were included in the review. We accessed pooled data using random-effect meta-analysis. RESULTS: Results of the meta-analyses show that low-volume hospitals were associated with a higher rate of surgical site infections (1.25 [1.01, 1.55]), longer length of stay (RR, 0.83[0.48-1.18]), increased cost of surgery (3.44, [2.57, 4.30]), 90-day complications (RR, 1.80[1.50-2.17]) and 30-day (RR, 2.33[1.27-4.28]), 90-day (RR, 1.26[1.05-1.51]), and 1-year mortality rates (RR, 2.26[1.32-3.88]) when compared to high-volume hospitals following THA. Except for two prospective studies, all were retrospective observational studies. CONCLUSIONS: These findings demonstrate superior outcomes following THA in high-volume hospitals. Together with the reduced cost of the surgical procedure, fewer complications may contribute to saving considerable opportunity costs annually. However, a need to define objective volume-thresholds with stronger evidence would be required. TRIAL REGISTRATION: PROSPERO CRD42019123776.

Relationship Between Staphylococcus aureus Carriage and Surgical Site Infections Following Total Hip and Knee Arthroplasty in the South Asian Population: Protocol for a Prospective Cohort Study.

BACKGROUND: Surgical site infections following total hip or knee arthroplasties have a reported rate of 0.49%-2.5% and can cause significant morbidity as well as tripling the cost of health care expenses. Both methicillin sensitive and methicillin resistant strains of Staphylococcus aureus surgical site infections have been established as a major risk factor for postoperative surgical site infections. S. aureus colonizes the nose, axillae, and perineal region in up to 20%-30% of individuals. Although the literature has reported a higher prevalence of methicillin resistant S. aureus in the South Asian population, routine preoperative screening and prophylaxis have not yet been implemented. OBJECTIVE: The primary objective of our study is to identify the relationship between preoperative colonization status of S. aureus and incidence of postoperative surgical site infections in patients undergoing following total hip and knee arthroplasties. As part of the secondary objectives of this study, we will also investigate patient characteristics acting as risk factors for S. aureus colonization as well as the outcomes of total hip and knee arthroplasty patients which are affected by surgical site infections. METHODS: This prospective cohort study will comprise of screening all patients older than 18 years of age admitted to the Aga Khan University Hospital for a primary total hip or knee arthroplasty for preoperative colonization with S. aureus. The patients will be followed postoperatively for up to one year following the surgery to assess the incidence of surgical site infections. The study duration will be 2 years (March 2018 to March 2020). For the purpose of screening, pooled swabs will be taken from the nose, axillae, and groin of each patient and inoculated in a brain heart infusion, followed by subculture onto mannitol salt agar and sheep blood agar. For methicillin resistant S. aureus identification, a cefoxitin disk screen will be done. Data will be analyzed using SPSS v23 and both univariate and multivariate regression analysis will be conducted. RESULTS: Data collection for this study will commence at the Aga Khan University Hospital, Pakistan during March 2018. CONCLUSIONS: This study will not only estimate the true burden caused by S. aureus in the population under study but will also help identify the patients at a high risk of surgical site infections so that appropriate interventions, including prophylaxis with antibiotics such as muciprocin ointment or linezolid, can be made. Given the differences in lifestyle, quality, and affordability of health care and the geographical variation in patterns of antibiotic resistance, this study will contribute significantly to providing incentive for routine screening and prophylaxis for S. aureus including methicillin resistant S. aureus colonization in the South Asian population. REGISTERED REPORT IDENTIFIER: RR1-10.2196/10219.

The effect of tranexamic acid in unilateral and bilateral total knee arthroplasty in the South Asian population: A retrospective cohort study.

INTRODUCTION: Together with evidence of higher bleeding tendencies, the vulnerability of the South-Asian population to anemia secondary to a higher prevalence of hemoglobinopathies and micronutrient deficiencies merits further exploration of the effects of tranexamic acid on this population. Additionally, limited access to self-care facilities and certain sociocultural beliefs and practices may not be conducive to a speedy recovery from surgical complications. The aim of this study is to investigate the effects of intraoperative administration of tranexamic acid during total knee arthroplasty when considering the South-Asian population. METHODOLOGY: Medical record files of 355 patients who underwent total knee arthroplasty (2007-2015) were reviewed to collect data regarding patient characteristics, surgical variables and post-operative complications. Unilateral and Bilateral total knee arthroplasty were studied separately. Analysis was done using t-test, Mann-Whitney U test, chi-square and Fisher's exact square where appropriate. The threshold for significance was p < 0.05. RESULTS: The study showed that for unilateral surgery, tranexamic acid caused a significant reduction in estimated blood loss (p-value=0.011), total operative time, calculated blood loss, and hemoglobin change (p-value<0.001) whereas in bilateral surgery, tranexamic acid only caused a significant reduction in calculated blood loss (p-value < 0.001) and hemoglobin change (p-value=0.001). Interestingly, in those who received tranexamic acid vs. those who did not, there was a significant increase in length of hospital stay (p<0.001) and special care unit admissions (p-value=0.033) in unilateral and bilateral surgery respectively. CONCLUSIONS: Although tranexamic acid effectively reduces intraoperative blood loss, it does not have an effect on the need for post-operative blood transfusions. The increased length of stay and special care unit admissions associated with tranexamic acid use should be explored further to reveal the complete safety profile of tranexamic acid administration in the South-Asian population during total knee arthroplasty.

Total knee Arthroplasty: risk factors for allogeneic blood transfusions in the South Asian population.

BACKGROUND: Total knee arthroplasty (TKA) is the recommended treatment for end-stage knee osteoarthritis. Considering the various risks associated with intra and postoperative blood transfusions, better understanding is required with respect to the risk factors contributing to a greater possibility of blood transfusion during or after surgery. Although literature highlights several such factors, our study is among the first to identify these risk factors in the South Asian population which differs from other populations in several ways. METHODS: The study consists of a review of 658 patients undergoing TKA from 2005 to 2015. Data was obtained from patient medical records and was analysed using logistic regression analysis. The relationship between each predictor and the outcome variable was calculated as an Odds ratio (OR), the threshold of significance for which was p = 0.25 and p = 0.05 for univariate and multivariable analysis respectively. RESULTS: The mean age of the patient population was 63 years (78% female), 25% of whom received one or more blood transfusions. Multivariable analysis revealed 5 significant independent predictors for increased risk of blood transfusions including bilateral knee surgery (OR:5.51), preoperative anemia (OR:4.15), higher ASA (American Society of Anaesthesiologists) status (3-4) (OR:1.92), female sex (OR:3.44) and BMI (Body mass index) ≤30 (OR:1.79) while increasing co-morbidities and age (>60) were found to be insignificant. CONCLUSIONS: The factors identified for the South Asian population are largely similar to those for other populations. Identification of high risk patients will permit the application of an international multipronged approach which not only targets the modifiable risk factors but also the decision making process and blood management protocols in order to minimize the transfusion associated risks for a patient undergoing a TKA.