Utility of Spatial Point-Pattern Analysis Using Residential and Workplace Geospatial Information to Localize Potential Outbreak Sources.

Identifying the source of an outbreak facilitates its control. Spatial methods are not optimally used in outbreak investigation, due to a mix of the complexities involved (e.g., methods requiring additional parameter selection), imperfect performance, and lack of confidence in existing options. We simulated 30 mock outbreaks and compared 5 simple methods that do not require parameter selection but could select between mock cases' residential and workplace addresses to localize the source. Each category of site had a unique spatial distribution; residential and workplace address were visually and statistically clustered around the residential neighborhood and city center sites respectively, suggesting that the value of workplace addresses is tied to the location where an outbreak might originate. A modification to centrographic statistics that we propose-the center of minimum geometric distance with address selection-was able to localize the mock outbreak source to within a 500 m radius in almost all instances when using workplace in combination with residential addresses. In the sensitivity analysis, when given sufficient workplace data, the method performed well in various scenarios with only 10 cases. It was also successful when applied to past outbreaks, except for a multisite outbreak from a common food supplier.

Role of outpatient parenteral antibiotic therapy in the treatment of community acquired skin and soft tissue infections in Singapore.

BACKGROUND: Treatment of community acquired skin and soft tissue infections (SSTIs) is a common indication for outpatient parenteral antibiotic therapy (OPAT) in USA, UK and Australasia, however data from Asia are lacking. OPAT is well established within the Singapore healthcare since 2002, however, systematic use of OPAT for the treatment of SSTIs remains infrequent. In this report, we describe the treatment and outcome of patients with SSTIs referred directly from Emergency Department (ED) to OPAT for continuation of intravenous (IV) antibiotics in Singapore, thus avoiding potential hospital admission. METHOD: This is a single center university hospital retrospective study of patients with SSTIs presenting to ED who were assessed to require IV antibiotics and accepted to the OPAT clinic for continuation of IV treatment. Exclusion criteria were: haemodynamic instability, uncontrolled or serious underlying co-morbidities, necessity for inpatient surgical drainage, facial cellulitis and cephalosporin allergy. Patients returned daily to the hospital's OPAT clinic for administration of IV antibiotics and review, then switched to oral antibiotics on improvement. RESULTS: From 7 February 2012 to 31 July 2015, 120 patients with SSTIs were treated in OPAT. Median age was 56 years and 63% were male. Lower limbs were affected in 91%. Diabetes was present in 20%. Sixty-seven (56%) had been treated with oral antibiotics for a median duration of 3 days prior to OPAT treatment. Common symptoms were erythema (100%), swelling (96%), pain (88%) and fever (55%). Antibiotics administered were IV cefazolin with oral probenecid (71%) or IV ceftriaxone (29%) for median 3 days then oral cloxacillin (85%) for median 7 days. Clinical improvement occurred in 90%. Twelve patients (10%) were hospitalized for worsening cellulitis, with 4 patients requiring surgical drainage of abscess. Microbiological cultures from 2 patients with drained abscess grew methicillin sensitive Staphylococcus aureus (MSSA) and Klebsiella pneumoniae, both of which were susceptible to cefazolin and ceftriaxone. Hospital bed days saved was 318 days. CONCLUSION: OPAT treatment of community acquired SSTIs in a selected patient population has good outcomes in Singapore. Treatment with IV cefazolin or IV ceftriaxone was successful in the majority with low hospital readmission rate.

Post-Traumatic Raynaud's Phenomenon: A Case Report.

BACKGROUND: Raynaud's phenomenon has multiple etiologies, ranging from occupational causes to systemic disease. Most occupational causes of Raynaud's phenomenon usually present with vascular compromise. CASE REPORT: A 41-year-old Chinese woman presented to the emergency department with progressive pain and bluish discoloration over her right index finger after minor trauma. The clinical examination revealed discoloration over multiple fingertips on both hands. She was diagnosed with Raynaud's phenomenon with possible underlying systemic disease. Additional laboratory workup led to the diagnosis of systemic lupus erythematosus with complex regional pain syndrome. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: It is rare for the emergency physician to diagnose Raynaud's phenomenon in the setting of minor trauma. It is important to diagnose this condition because of its potential complications.

Transient Coagulopathy Due to Wasp Sting: A Case Report.

BACKGROUND: Insect venom anaphylaxis is a potentially life-threatening disorder. Transient coagulopathy in insect venom anaphylaxis is a rare phenomenon. CASE REPORT: A 41-year-old man presented to the Emergency Department (ED) with hypotension after a run in a park. History and examination revealed signs of anaphylactic shock. A deranged coagulation profile with a normal platelet count led to the diagnosis of wasp sting anaphylaxis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Transient deranged coagulation profile with a normal platelet count may arise from insect venom anaphylaxis. This specific finding may aid the emergency physician in making a diagnosis of anaphylactic shock in an otherwise healthy patient presenting with shock with no apparent cause.

Risk stratification and rapid geriatric screening in an emergency department - a quasi-randomised controlled trial.

BACKGROUND: To determine if risk stratification followed by rapid geriatric screening in an emergency department (ED) reduced functional decline, ED reattendance and hospitalisation. METHOD: This was a quasi-randomised controlled trial. Patients were randomised by the last digit of their national registration identity card (NRIC). Odd number controls received standard ED care; even number patients received geriatric screening, followed by intervention and/or onward referrals. Patients were followed up for 12 months. RESULTS: There were 500 and 280 patients in the control and intervention groups. The intervention group had higher Triage Risk Screening Tool (TRST) scores (34.3% vs 25.4% TRST ≥3, p = 0.01) and lower baseline Instrumental Activity of Daily Living (IADL) scores (22.84 vs 24.18, p < 0.01). 82.9% of the intervention group had unmet needs; 62.1% accepted our interventions. Common positive findings were fall risk (65.0%), vision (61.4%), and footwear (58.2%). 28.2% were referred to a geriatric clinic and 11.8% were admitted. 425 (85.0%) controls and 234 (83.6%) in the intervention group completed their follow-up. After adjusting for TRST and baseline IADL, the intervention group had significant preservation in function (Basic ADL -0.99 vs -0.24, p < 0.01; IADL -2.57 vs +0.45, p < 0.01) at 12 months. The reduction in ED reattendance (OR0.75, CI 0.55-1.03, p = 0.07) and hospitalization (OR0.77, CI0.57-1.04, p = 0.09) were not significant, however the real difference would have been wider as 21.2% of the control group received geriatric screening at the request of the ED doctor. A major limitation was that a large proportion of patients who were randomized to the intervention group either refused (18.8%) or left the ED before being approached (32.0%). These two groups were not followed up, and hence were excluded in our analysis. CONCLUSION: Risk stratification and focused geriatric screening in ED resulted in significant preservation of patients' function at 12 months. TRIAL REGISTRATION: National Healthcare Group (NHG) Domain Specific Review Board (DSRB) C/09/023. Registered 5th March 2009.

Real-time prediction of waiting time in the emergency department, using quantile regression.

STUDY OBJECTIVE: Emergency department (ED) waiting times can affect patient satisfaction and quality of care. We develop and validate a model that predicts an individual patient's median and 95th percentile waiting time by using only data available at triage. METHODS: From the existing ED information system, we extracted date and time of triage completion, start time of emergency physician consultation, and patient acuity category (1=most urgent, 3=least urgent). Quantile regression was applied for model development and parameter estimation by using visits from January 2011. We assessed absolute prediction error, defined as the median difference between the 50th percentile (median) predicted waiting time and actual waiting time, and the proportion of underestimated prediction, defined as the percentage of patients whose actual waiting time exceeded the 95th percentile prediction. The model was validated retrospectively with June 2010 data and prospectively with data from April to June 2011 after integration with the existing ED information system. RESULTS: The derivation set included 13,200 ED visits; 903 (6.8%) were patient acuity category 1, 5,530 (41.9%) were patient acuity category 2, and 6,767 (51.3%) were patient acuity category 3. The median and 95th percentile waiting times were 17 and 57 minutes for patient acuity category 2 and 21 and 89 minutes for patient acuity category 3, respectively. The final model used predictors of patient acuity category, patient queue sizes, and flow rates only. In the retrospective validation, 5.9% of patient acuity category 2 and 5.4% of category 3 waiting times were underestimated. The median absolute prediction error was 11.9 minutes (interquantile range [IQR] 5.9 to 22.1 minutes) for patient acuity category 2 and 15.7 minutes (IQR 7.5 to 30.1 minutes) for category 3. In prospective validation, 4.3% of patient acuity category 2 and 5.8% of category 3 waiting times were underestimated. The median absolute prediction error was 9.2 minutes (IQR 4.4 to 15.1 minutes) for patient acuity category 2 and 12.9 minutes (IQR 6.5 to 22.5 minutes) for category 3. CONCLUSION: Using only a few data elements available at triage, the model predicts individual patients' waiting time with good accuracy.

Use of STONE Score to Predict Urolithiasis in an Asian Emergency Department.

Background: The STONE score was developed to predict uncomplicated ureteral stones in patients so that they can be managed without imaging. Validation studies had been conducted previously but the results were varied. This study aims to investigate the utility of the STONE score in an emergency department in Singapore. Methods: We retrospectively analyzed the records of adult patients presenting with ureteric colic in the emergency department in 2015. STONE score as well as the proportion of urolithiasis diagnosed on advanced imaging in each STONE score group were calculated. Logistic regression was used to calculate the odds ratios (ORs) for the STONE score components in our study and compared with the ORs obtained in the original study. Measures of diagnostic accuracy for a high STONE score were also calculated. Results: 753 cases were included in the final analysis. Among patients with a high STONE score, 66.7% had urolithiasis and 2.6% had significant alternative diagnoses. Compared to original studies, ORs for the STONE score components obtained for our study were different. From our study, the sensitivity of a high STONE score was 47.0%, specificity was 68.7%, positive predictive value was 66.7%, negative predictive value was 49.3%, positive likelihood ratio was 1.50, and negative likelihood ratio was 0.77. Conclusion: The STONE score is not expected to perform well in Singapore based on our study. It should be used with caution in similar Asian populations.

Risk prediction models to guide antibiotic prescribing: a study on adult patients with uncomplicated upper respiratory tract infections in an emergency department.

BACKGROUND: Appropriate antibiotic prescribing is key to combating antimicrobial resistance. Upper respiratory tract infections (URTIs) are common reasons for emergency department (ED) visits and antibiotic use. Differentiating between bacterial and viral infections is not straightforward. We aim to provide an evidence-based clinical decision support tool for antibiotic prescribing using prediction models developed from local data. METHODS: Seven hundred-fifteen patients with uncomplicated URTI were recruited and analysed from Singapore's busiest ED, Tan Tock Seng Hospital, from June 2016 to November 2018. Confirmatory tests were performed using the multiplex polymerase chain reaction (PCR) test for respiratory viruses and point-of-care test for C-reactive protein. Demographic, clinical and laboratory data were extracted from the hospital electronic medical records. Seventy percent of the data was used for training and the remaining 30% was used for validation. Decision trees, LASSO and logistic regression models were built to predict when antibiotics were not needed. RESULTS: The median age of the cohort was 36 years old, with 61.2% being male. Temperature and pulse rate were significant factors in all 3 models. The area under the receiver operating curve (AUC) on the validation set for the models were similar. (LASSO: 0.70 [95% CI: 0.62-0.77], logistic regression: 0.72 [95% CI: 0.65-0.79], decision tree: 0.67 [95% CI: 0.59-0.74]). Combining the results from all models, 58.3% of study participants would not need antibiotics. CONCLUSION: The models can be easily deployed as a decision support tool to guide antibiotic prescribing in busy EDs.

The Little India riot: experience of an emergency department in Singapore.

INTRODUCTION: Singapore experienced its second riot in 40 years on 8 December 2013, in the area known as Little India. A retrospective review of 36 casualties treated at the emergency department was conducted to evaluate injury patterns. METHODS: Characteristics including the rate of arrival, injury severity, type and location, and disposition of the casualties were analysed. RESULTS: The injuries were predominantly mild (97.2%), with the most common injuries involving the head (50.0%) and limbs (38.9%). 97.2% of the casualties were managed as outpatient cases. CONCLUSION: The majority of the injuries in this incident were mild and could be managed as outpatient cases. Important lessons were learnt from the incident about the utilisation of manpower and safety of staff in the emergency department.

Patients with pelvic fracture: what factors are associated with mortality?

BACKGROUND: Pelvic fracture is one of the major injuries that lead to death in patients who sustain high-impact injuries such as road traffic accidents and falls from height. AIMS: This study aims to look at the epidemiology and the significant predictors of mortality in victims with pelvic fracture presenting to the emergency department (ED) of an urban Asian city. METHODS: This was a retrospective data analysis of all trauma patients with pelvic fracture who were treated at the ED of an urban adult hospital in Singapore from April 2001 to December 2004. Student's t-test and χ(2) test were used in statistical analysis where appropriate. RESULTS: The study included 179 consecutive patients. Sixty-four percent of patients were males, and 71% of patients were in the 20-49-year-old age group. Road traffic accidents and falls from height were the two most common mechanisms of injury. Mortality rate was 37%. Pelvic fracture severity, shock and coma at presentation, and the presence of concurrent head and chest injuries were associated with increased mortality. Gender, other mechanisms of injury and other concomitant injuries were not associated with increased mortality. CONCLUSIONS: The mortality rate of trauma patients with pelvic fracture continues to be high. In such patients, predictors of mortality are the severity of the pelvic fracture, the presence of coma, shock, and head and chest injuries.