Emergency department presentation of the pediatric systemic inflammatory response syndrome.

OBJECTIVES: The epidemiology of the systemic inflammatory response syndrome (SIRS) in children is poorly understood. We sought to determine national estimates of the incidence of pediatric SIRS and its corresponding clinical etiologies presenting to US emergency departments (EDs) using current definitions. METHODS: We analyzed ED visits by children younger than 18 years from 2007 to 2010 in the National Hospital Ambulatory Medical Care Survey. We used a Bayesian logical framework of prior probability distributions for white blood cell count result to make minimum, moderate, and maximum estimates for pediatric SIRS. RESULTS: Taking the minimum and maximum estimates as modified credible intervals, we report an overall incidence of pediatric SIRS presenting to the ED to be 21.7% (95% modified credible interval, 18.1%-25.4%). The national moderate estimate of pediatric ED visits presenting with SIRS was approximately 6.2 million per year. Children with SIRS and without SIRS had similar baseline characteristics, but SIRS patients were younger (2.9 vs 5.5 years; P < 0.0001), had higher triage acuity (emergent, 9.0 vs 6.3%; P < 0.0001), and were more often admitted (7.0 vs 2.4%; P < 0.0001) than children without SIRS. Based on the moderate estimate, infection was the most common (53%) associated etiology, followed by trauma (10%). Other traditional categories of SIRS were extremely rare. Of note, 35% of children with SIRS did not fall into any of the previously established categories. CONCLUSIONS: Pediatric SIRS is common; its associated clinical contexts include potentially dangerous etiologies; many cases of pediatric SIRS can be recognized in triage; and there is significant heterogeneity in the etiology of pediatric SIRS.

Impact of metformin use on the prognostic value of lactate in sepsis.

OBJECTIVE: The objective of this study is to determine if metformin use affects the prevalence and prognostic value of hyperlactatemia to predict mortality in septic adult emergency department (ED) patients. METHODS: This is a single-center retrospective cohort study. Emergency department providers identified study subjects; data were collected from the medical record. PATIENTS: Adult ED patients with suspected infection and 2 or more systemic inflammatory response syndrome criteria were included. The outcome was 28-day mortality. The primary risk variable was serum lactate (<2.0, 2.0-3.9, ≥ 4.0 mmol/L) categorized by metformin use; covariates: demographics, Predisposition, Infection, Response, Organ Dysfunction score and metformin use contraindications. SETTING: The study was conducted at an urban teaching hospital; February 1, 2007 to October 31, 2008. RESULTS: A total of 1947 ED patients were enrolled; 192 (10%) were taking metformin; 305 (16%) died within 28 days. Metformin users had higher median lactate levels than nonusers (2.2 mmol/L [interquartile range, 1.6-3.2] vs 1.9 mmol/L [interquartile range, 1.3-2.8]) and a higher, although nonsignificant, prevalence of hyperlactatemia (lactate ≥ 4.0 mmol/L) (17% vs 13%) (P = .17). In multivariate analysis (reference group nonmetformin users, lactate <2.0 mmol/L), hyperlactatemia was associated with an increased adjusted 28-day mortality risk among nonmetformin users (odds ratio [OR], 3.18; P < .01) but not among metformin users (OR, 0.54; P = .33). In addition, nonmetformin users had a higher adjusted mortality risk than metformin users (OR, 2.49; P < .01). These differences remained significant when only diabetic patients were analyzed. CONCLUSIONS: In this study of adult ED patients with suspected sepsis, metformin users had slightly higher median lactate levels and prevalence of hyperlactatemia. However, hyperlactatemia did not predict an increased mortality risk in patients taking metformin.

Serum lactate is a better predictor of short-term mortality when stratified by C-reactive protein in adult emergency department patients hospitalized for a suspected infection.

STUDY OBJECTIVE: We determine whether C-reactive protein (CRP) adds prognostic value to serum lactate levels when assessing mortality risk in emergency department (ED) patients admitted for a suspected infection. METHODS: This was an observational cohort of unique adult patients (≥ 21 years of age) who had lactate and CRP testing in the ED and were admitted for a suspected infection during a 1-year period. All data were collected through retrospective chart review. The study site is an urban teaching hospital with an approximate annual census of 95,000 patients. The endpoint was 28-day inpatient mortality. RESULTS: One thousand one hundred forty-three patients had lactate and CRP testing in the ED, an admitting diagnosis of infection, and complete records. Twenty-eight-day inpatient mortality for patients with both a lactate level greater than or equal to 4.0 mmol/L and CRP level greater than 10.0 mg/dL was 44.0% (95% confidence interval [CI] 32.5% to 55.5%), for lactate greater than or equal to 4.0 mmol/L and CRP less than or equal to 10.0 mg/dL, it was 9.7% (95% CI 2.7% to 16.7%), and for lactate level less than 4.0 mmol/L, it was 9.1% (95% CI 7.3% to 10.9%). In a logistic regression model that included patient demographics and Charlson score, as well as 4 separate dichotomous variables that were positive only in subjects with (1) serum lactate greater than or equal to 4.0 mmol/L and CRP level greater than 10.0 mg/dL, (2) lactate level greater than or equal to 4.0 mmol/L and CRP level less than or equal to 10.0 mg/dL, (3) lactate level less than 4.0 mmol/L and CRP level greater than 10.0 mg/dL, and (4) lactate level less than 4.0 mmol/L and CRP level less than or equal to 10.0 mg/dL (as reference), patients with both a lactate level greater than or equal to 4.0 mmol/L and CRP greater than 10 mg/dL had an increased risk of 28-day inpatient mortality (odds ratio 12.3; 95% CI 6.8 to 22.3). CONCLUSION: In this cohort, patients with both an increased CRP level and hyperlactatemia had a higher mortality rate than patients with abnormalities of either laboratory test in isolation.

Epidemiology of the Systemic Inflammatory Response Syndrome (SIRS) in the emergency department.

INTRODUCTION: Consensus guidelines recommend sepsis screening for adults with systemic inflammatory response syndrome (SIRS), but the epidemiology of SIRS among adult emergency department (ED) patients is poorly understood. Recent emphasis on cost-effective, outcomes-based healthcare prompts the evaluation of the performance of large-scale efforts such as sepsis screening. We studied a nationally representative sample to clarify the epidemiology of SIRS in the ED and subsequent category of illness. METHODS: This was a retrospective analysis of ED visits by adults from 2007 to 2010 in the National Hospital Ambulatory Medical Care Survey (NHAMCS). We estimated the incidence of SIRS using initial ED vital signs and a Bayesian construct to estimate white blood cell count based on test ordering. We report estimates with Bayesian modified credible intervals (mCIs). RESULTS: We used 103,701 raw patient encounters in NHAMCS to estimate 372,844,465 ED visits over the 4-year period. The moderate estimate of SIRS in the ED was 17.8% (95% mCI: 9.7 to 26%). This yields a national moderate estimate of approximately 16.6 million adult ED visits with SIRS per year. Adults with and without SIRS had similar demographic characteristics, but those with SIRS were more likely to be categorized as emergent in triage (17.7% versus 9.9%, p<0.001), stay longer in the ED (210 minutes versus 153 minutes, p<0.0001), and were more likely to be admitted (31.5% versus 12.5%, p<0.0001). Infection accounted for only 26% of SIRS patients. Traumatic causes of SIRS comprised 10% of presentations; other traditional categories of SIRS were rare. CONCLUSION: SIRS is very common in the ED. Infectious etiologies make up only a quarter of adult SIRS cases. SIRS may be more useful if modified by clinician judgment when used as a screening test in the rapid identification and assessment of patients with the potential for sepsis. [West J Emerg Med. 2014;15(3):329-336.].

From vital signs to clinical outcomes for patients with sepsis: a machine learning basis for a clinical decision support system.

OBJECTIVE: To develop a decision support system to identify patients at high risk for hyperlactatemia based upon routinely measured vital signs and laboratory studies. MATERIALS AND METHODS: Electronic health records of 741 adult patients at the University of California Davis Health System who met at least two systemic inflammatory response syndrome criteria were used to associate patients' vital signs, white blood cell count (WBC), with sepsis occurrence and mortality. Generative and discriminative classification (naïve Bayes, support vector machines, Gaussian mixture models, hidden Markov models) were used to integrate heterogeneous patient data and form a predictive tool for the inference of lactate level and mortality risk. RESULTS: An accuracy of 0.99 and discriminability of 1.00 area under the receiver operating characteristic curve (AUC) for lactate level prediction was obtained when the vital signs and WBC measurements were analysed in a 24 h time bin. An accuracy of 0.73 and discriminability of 0.73 AUC for mortality prediction in patients with sepsis was achieved with only three features: median of lactate levels, mean arterial pressure, and median absolute deviation of the respiratory rate. DISCUSSION: This study introduces a new scheme for the prediction of lactate levels and mortality risk from patient vital signs and WBC. Accurate prediction of both these variables can drive the appropriate response by clinical staff and thus may have important implications for patient health and treatment outcome. CONCLUSIONS: Effective predictions of lactate levels and mortality risk can be provided with a few clinical variables when the temporal aspect and variability of patient data are considered.

Hyperlactatemia affects the association of hyperglycemia with mortality in nondiabetic adults with sepsis.

BACKGROUND: Admission hyperglycemia has been reported as a mortality risk factor for septic nondiabetic patients; however, hyperglycemia's known association with hyperlactatemia was not addressed in these analyses. OBJECTIVES: The objective was to determine whether the association of hyperglycemia with mortality remains significant when adjusted for concurrent hyperlactatemia. METHODS: This was a post hoc, nested analysis of a retrospective cohort study performed at a single center. Providers had identified study subjects during their emergency department (ED) encounters; all data were collected from the electronic medical record (EMR). Nondiabetic adult ED patients hospitalized for suspected infection, two or more systemic inflammatory response syndrome (SIRS) criteria, and simultaneous lactate and glucose testing in the ED were enrolled. The setting was the ED of an urban teaching hospital from 2007 to 2009. To evaluate the association of hyperglycemia (glucose > 200 mg/dL) with hyperlactatemia (lactate ≥ 4.0 mmol/L), a logistic regression model was created. The outcome was a diagnosis of hyperlactatemia, and the primary variable of interest was hyperglycemia. A second model was created to determine if coexisting hyperlactatemia affects hyperglycemia's association with mortality; the main outcome was 28-day mortality, and the primary risk variable was hyperglycemia with an interaction term for simultaneous hyperlactatemia. Both models were adjusted for demographics; comorbidities; presenting infectious source; and objective evidence of renal, respiratory, hematologic, or cardiovascular dysfunction. RESULTS: A total of 1,236 ED patients were included, and the median age was 77 years (interquartile range [IQR] = 60 to 87 years). A total of 115 (9.3%) subjects were hyperglycemic, 162 (13%) were hyperlactatemic, and 214 (17%) died within 28 days of their initial ED visits. After adjustment, hyperglycemia was significantly associated with simultaneous hyperlactatemia (odds ratio [OR] = 4.14, 95% confidence interval [CI] = 2.65 to 6.45). Hyperglycemia and concurrent hyperlactatemia were associated with increased mortality risk (OR = 3.96, 95% CI = 2.01 to 7.79), but hyperglycemia in the absence of simultaneous hyperlactatemia was not (OR = 0.78, 95% CI = 0.39 to 1.57). CONCLUSIONS: In this cohort of septic adult nondiabetic patients, mortality risk did not increase with hyperglycemia unless associated with simultaneous hyperlactatemia. The previously reported association of hyperglycemia with mortality in nondiabetic sepsis may be due to the association of hyperglycemia with hyperlactatemia.