Racial and ethnic differences in the rates of urinary tract infections in febrile infants in the emergency department

Pediatric Urinary Tract Infections

Urinary tract infection (UTI) is frequent in the first year of life with bowel and bladder dysfunction, GU tract abnormalities, neurogenic bladder, and the intact prepuce conveying an increased risk. Urine culture is the gold standard for diagnosis. Antibiotics are tailored to resistance patterns. Guidelines have been established to direct the evaluation for GU anomalies but differ significantly. Bladder and bowel dysfunction is important to screen for and treat in potty-trained patients. Circumcised boys with febrile UTIs are more likely to have anatomic abnormalities than uncircumcised boys.

General Characteristics and Current State of Antibiotic Resistance in Pediatric Urinary Tract Infection-A Single Center Experience

Urinary tract infection (UTI) represents one of the most common bacterial infections in children, mainly caused by Gram-negative bacteria. Empirical antibiotic treatment is based on international and national guidelines for treating UTIs in children and is individualized with local antibiotic resistance patterns. The aim of this study is to bring a clear view of present-day particularities of UTIs in children.

METHODS

We analyzed 210 positive urine cultures identified in 141 pediatric patients admitted to the hospital over a 6-month period.

RESULTS

The majority of patients were females (57%) with a median age of 5 years (IQR 12), while male patients revealed a median age of 2 (IQR 7). Most patients originated from urban areas (53%). Only 18 patients (12.76%) were identified with underlying Congenital Anomalies of the Kidney and Urinary Tract (CAKUT). Escherichia Coli was the most frequent pathogen. Increased antibiotic resistance was found in commonly-used antibiotics Ampicillin and Trimethoprim/Sulfamethoxazole, and in the case of patients with CAKUT. Suitable antibiotics for treating a Gram-negative UTI are aminoglycosides, Meropenem, third-generation Cephalosporins, and Nitrofurantoin. Vancomycin upholds efficacy in treating a Gram-positive pediatric UTI.

CONCLUSION

Periodical analysis needs to be performed in order to constantly update clinicians on uropathogenic antibiotic resistance and optimal empirical treatment options.

Computer-assisted decision support for the usage of preventive antibacterial therapy in children with febrile pyelonephritis: A preliminary study

Urinary tract infection (UTI) is one of the most common infectious diseases among children, but there is controversy regarding the use of preventive antibiotics for children first diagnosed with febrile pyelonephritis. To the best of our knowledge, no studies have addressed this issue by the deep learning technology. Therefore, in the current study, we conducted a study using Tc 99 m - DMSA renal static imaging data to investigate the need for preventive antibiotics on children first diagnosed with febrile pyelonephritis under 2 years old. The self-collected dataset comprised 64 children who did not require preventive antibiotic treatments and 112 children who did. Using several classic deep learning models, we verified that it is feasible to screen whether the first diagnosed children with febrile pyelonephritis require preventive antibacterial therapy, achieving a graded diagnosis. With the AlexNet model, we obtained accuracy of 84.05%, sensitivity of 81.71% and specificity of 86.70%, respectively. The experimental results indicate that deep learning technology could provide a new avenue to implement computer-assisted decision support for the diagnosis of the febrile pyelonephritis.

A retrospective analysis of the incidence and risk factors of perioperative urinary tract infections after total hysterectomy

INTRODUCTION

Perioperative urinary tract infections (PUTIs) are common in the United States and are a significant contributor to high healthcare costs. There is a lack of large studies on the risk factors for PUTIs after total hysterectomy (TH).

METHODS

We conducted a retrospective study using a national inpatient sample (NIS) of 445,380 patients from 2010 to 2019 to analyze the risk factors and annual incidence of PUTIs associated with TH perioperatively.

RESULTS

PUTIs were found in 9087 patients overall, showing a 2.0% incidence. There were substantial differences in the incidence of PUTIs based on age group (P < 0.001). Between the two groups, there was consistently a significant difference in the type of insurance, hospital location, hospital bed size, and hospital type (P < 0.001). Patients with PUTIs exhibited a significantly higher number of comorbidities (P < 0.001). Unsurprisingly, patients with PUTIs had a longer median length of stay (5 days vs. 2 days; P < 0.001) and a higher in-hospital death rate (from 0.1 to 1.1%; P < 0.001). Thus, the overall hospitalization expenditures increased by $27,500 in the median ($60,426 vs. $32,926, P < 0.001) as PUTIs increased medical costs. Elective hospitalizations are less common in patients with PUTIs (66.8% vs. 87.6%; P < 0.001). According to multivariate logistic regression study, the following were risk variables for PUTIs following TH: over 45 years old; number of comorbidities (≥ 1); bed size of hospital (medium, large); teaching hospital; region of hospital(south, west); preoperative comorbidities (alcohol abuse, deficiency anemia, chronic blood loss anemia, congestive heart failure, diabetes, drug abuse, hypertension, hypothyroidism, lymphoma, fluid and electrolyte disorders, metastatic cancer, other neurological disorders, paralysis, peripheral vascular disorders, psychoses, pulmonary circulation disorders, renal failure, solid tumor without metastasis, valvular disease, weight loss); and complications (sepsis, acute myocardial infarction, deep vein thrombosis, gastrointestinal hemorrhage, pneumonia, stroke, wound infection, wound rupture, hemorrhage, pulmonary embolism, blood transfusion, postoperative delirium).

CONCLUSIONS

The findings suggest that identifying these risk factors can lead to improved preventive strategies and management of PUTIs in TH patients. Counseling should be done prior to surgery to reduce the incidence of PUTIs.

THE MANUSCRIPT ADDS TO CURRENT KNOWLEDGE

In medical practice, the identification of risk factors can lead to improved patient prevention and treatment strategies. We conducted a retrospective study using a national inpatient sample (NIS) of 445,380 patients from 2010 to 2019 to analyze the risk factors and annual incidence of PUTIs associated with TH perioperatively. PUTIs were found in 9087 patients overall, showing a 2.0% incidence. We found that noted increased length of hospital stay, medical cost, number of pre-existing comorbidities, size of the hospital, teaching hospitals, and region to also a play a role in the risk of UTI's.

CLINICAL TOPICS

Urogynecology.

External Validation of the UTICalc with and Without Race for Pediatric Urinary Tract Infection

OBJECTIVE

To validate externally the UTICalc, a popular clinical decision support tool used to determine the risk of urinary tract infections (UTIs) in febrile children, and compare its performance with and without the inclusion of race and at differing risk thresholds.

METHODS

We performed a retrospective, singlecenter case-control study of febrile children (2-24 months) in an emergency department. Cases with culture-confirmed UTI were matched 1:1 to controls. We compared the performance of the original model which included race (version 1.0) to a revised model which did not consider race (version 3.0). We evaluated model performance at risk thresholds between 2% and 5%.

RESULTS

We included 185 cases and 197 controls (median age 8.4 months; IQR, 4.4-13.0 months; 60.5% girls). When using UTICalc version 1.0, the model area under the receiver operator characteristic curve (AUROC) was 73.4% (95% CI 68.4%-78.5%), which was similar to the version 3.0 model (73.8%; 95% CI 68.7%-78.8%). When using a 2% risk threshold, the version 3.0 model demonstrated a sensitivity of 96.7% and a specificity of 25.0%, with declines in sensitivity and gains in specificity at higher risk thresholds. Version 1.0 of the UTICalc had 12 false negatives, of whom 10 were Black (83%); whereas version 3.0 had 6 false negatives, of whom 2 were Black (33%).

CONCLUSIONS

Versions of the UTICalc with and without race had similar performance to each other with a slight decline from the original derivation sample. The removal of race did not adversely affect the accuracy of the UTICalc.

Epidemiology and Risk Factors of UTIs in Children-A Single-Center Observation

Urinary tract infections (UTIs) are one of childhood’s most common bacterial infections. The study aimed to determine the clinical symptoms, laboratory tests, risk factors, and etiology of different UTIs in children admitted to pediatric hospitals for three years. Methods: Patients with positive urine cultures diagnosed with acute pyelonephritis (APN) or cystitis (CYS) were analyzed for clinical symptoms, laboratory tests, risk factors, and etiology, depending on their age and sex. Results: We studied 948 children with UTIs (531 girls and 417 boys), with a median age of 12 (IQR 5−48 months). A total of 789 children had clinical symptoms; the main symptom was fever (63.4% of patients). Specific symptoms of UTIs were presented only in 16.3% of patients. Children with APN had shown significantly more frequent loss of appetite, vomiting, lethargy, seizures, and less frequent dysuria and haematuria than children with CYS. We found significantly higher median WBC, CRP, and leukocyturia in children with APN than with CYS. The risk factors of UTIs were presented in 46.6% of patients, of which 35.6% were children with APN and 61.7% with CYS. The main risk factor was CAKUT, more frequently diagnosed in children with CYS than APN, mainly in children <2 years. The most commonly isolated bacteria were Escherichia coli (74%). There was a higher percentage of urine samples with E. coli in girls than in boys. Other bacteria found were Klebsiella species, Pseudomonas aeruginosa, Proteus mirabilis, and Enterococcus species. Conclusions: Patients with APN were younger and had higher inflammatory markers. Often, fever is the only symptom of UTI in children, and other clinical signs are usually non-specific. The most common UTI etiology is E. coli, regardless of the clinical presentation and risk factors.

Racial Differences in Urine Testing of Febrile Young Children Presenting to Pediatric Hospitals

INTRODUCTION

Dating back to 2011, practice guidelines considered Black race a factor associated with lower risk of urinary tract infection (UTI). Race-based clinical decisions raise concerns about potential treatment disparities. We investigate urine testing (urinalysis and/or urine culture) among young febrile children in the emergency department (ED), revisits, and potential missed diagnoses by race/ethnicity.

METHODS

We performed a multicenter retrospective cohort study of children 2-24 months evaluated in 26 US EDs from 2009 to 2019 with a fever diagnosis. We evaluated longitudinal testing trends, constructed a generalized linear mixed-effects model to identify the association of race/ethnicity with testing, and characterized UTI diagnoses and ≤ 7-day revisits.

RESULTS

Of 734,730 included patients, 24.1% were Black. Variation in urine testing was observed by patient race/ethnicity (23.4% Black, 31.7% White, 33.9% Hispanic, 30.0% other race). Relative differences in testing persisted over time. Black patients had lower adjusted odds of testing (0.70, 95% confidence interval [CI] 0.69-0.71). Among patients with urine testing, 2.4% (95% CI 2.3-2.6%) of Black and 3.3% (95% CI 3.1-3.4%) of White patients were diagnosed with UTI. Among Black patients with urine testing on the index visit, 8.5% (95% CI 8.2-8.8%) had return visits compared to 7.6% (95% CI 7.5-7.8%) among those without urine testing on index visit. Among patients with urine testing on revisit, UTI diagnosis was similar by race/ethnicity.

CONCLUSION

Black patients had lower rates of urine testing and UTI diagnoses relative to other racial/ethnic groups. This was not associated with higher rates of missed diagnoses or unscheduled return visits.

Reassessment of the Role of Race in Calculating the Risk for Urinary Tract Infection: A Systematic Review and Meta-analysis

IMPORTANCE

A previously reported prediction model included a child's race to estimate risk of urinary tract infection (UTI), but race-conscious medicine encourages investigating how race is likely to be a proxy for other factors that should instead be used for risk prediction.

OBJECTIVES

To systematically review the available literature to evaluate the robustness of the association between race and UTI and to assess whether other variables could replace race as a variable in a previously developed prediction tool without adversely affecting its accuracy.

DATA SOURCE

MEDLINE was searched through May 28, 2021.

STUDY SELECTION

English-language studies that reported data on the prevalence of UTI according to race for children younger than 18 years were included.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers assessed studies for risk of bias and abstracted data. Random-effects models were used to pool odds ratios, and meta-regression was used to explore heterogeneity.

MAIN OUTCOMES AND MEASURES

Odds of UTI among non-Black children vs Black children.

RESULTS

Sixteen studies (17 845 children) were included. In the primary analysis, which included 11 studies, the pooled odds ratio of UTI among non-Black children was 2.44-fold higher (95% CI, 1.87-3.20) than among Black children. The corresponding odds ratio in studies with low or very low risk of bias was 4.84-fold higher (95% CI, 3.16-7.41; I2 = 0%) among non-Black children than among Black children. Replacing race with history of UTI and duration of fever resulted in a model with similar accuracy (training cohort: overall sensitivity, 96% [95% CI, 94%-98%]; overall specificity, 35% [95%, 32%-38%]; overall area under the receiver operating characteristic curve, 0.80 [95% CI, 0.77-0.82]; validation cohort: overall sensitivity, 97% [95% CI, 90%-100%]; overall specificity, 32% [95% CI, 26%-37%]; overall area under the receiver operating characteristic curve, 0.84 [95% CI, 0.77-0.92]).

CONCLUSIONS AND RELEVANCE

Although previous studies suggested that an association between race and UTI exists, because of the issues associated with the inclusion of race in decision models, we replaced the variable of race with history of UTI and duration of fever in a previously developed risk prediction model and found similar accuracy.

Risk Factors for the Development of Febrile Recurrences in Children with a History of Urinary Tract Infection

OBJECTIVE

To identify risk factors for febrile recurrence of urinary tract infections (UTIs) in children with a history of UTI.

STUDY DESIGN

We included 500 children aged 2-72 months with a history of UTI who were followed prospectively for approximately 2 years in the context of 2 previously conducted studies (Randomized Intervention for Children with Vesicoureteral Reflux and Careful Urinary Tract Infection Evaluation). We identified significant risk factors for febrile recurrences among children not receiving antimicrobial prophylaxis using univariate and multivariate logistic regression.

RESULT

On univariate analysis, non-Black race, febrile index UTI, bowel-bladder dysfunction, grade IV vesicoureteral reflux, renal scarring at baseline, and renal-bladder ultrasound abnormalities were associated with febrile recurrence. On multivariate analysis, the following variables independently increased the odds of febrile recurrences (OR; 95% CI): non-Black race (7.1; 1.5-127.9), bowel-bladder dysfunction (2.6; 1.1-5.3), febrile index UTI (2.5; 1.1-6.9), abnormalities on renal-bladder ultrasound scan (2.6; 1.2-5.6), grade IV vesicoureteral reflux (3.9; 1.4-10.5), and renal scarring at baseline (4.7; 1.2-19.1).

CONCLUSIONS

Non-Black race and grade IV vesicoureteral reflux increased the odds of febrile recurrence of UTI. Although our findings should stimulate other studies to further explore the relationship between race and UTIs, given that the link between race and UTI recurrence is unclear, race should not be used to make decisions regarding management of children with a UTI.

Clinical Features for the Diagnosis of Pediatric Urinary Tract Infections: Systematic Review and Meta-Analysis

PURPOSE

Accurate diagnosis of urinary tract infection in children is essential because children left untreated can experience permanent renal injury. We aimed to assess the diagnostic value of clinical features of pediatric urinary tract infection.

METHODS

We performed a systematic review and meta-analysis of diagnostic test accuracy studies in ambulatory care. We searched the PubMed, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, Health Technology Assessment, and Database of Abstracts of Reviews of Effects databases from inception to January 27, 2020 for studies reporting 2 × 2 diagnostic accuracy data for clinical features compared with urine culture in children aged <18 years. For each clinical feature, we calculated likelihood ratios and posttest probabilities of urinary tract infection. To estimate summary parameters, we conducted a bivariate random effects meta-analysis and hierarchical summary receiver operating characteristic analysis.

RESULTS

A total of 35 studies (N = 78,427 patients) of moderate to high quality were included, providing information on 58 clinical features and 6 prediction rules. Only circumcision (negative likelihood ratio [LR-] 0.24; 95% CI, 0.08-0.72; n = 8), stridor (LR- 0.20; 95% CI, 0.05-0.81; n = 1), and diaper rash (LR- 0.13; 95% CI, 0.02-0.92; n = 1) were useful for ruling out urinary tract infection. Body temperature or fever duration showed limited diagnostic value (area under the receiver operating characteristic curve 0.61; 95% CI, 0.47-0.73; n = 16). The Diagnosis of Urinary Tract Infection in Young Children score, Gorelick Scale score, and UTIcalc (https://uticalc.pitt.edu) might be useful to identify children eligible for urine sampling.

CONCLUSIONS

Few clinical signs and symptoms are useful for diagnosing or ruling out urinary tract infection in children. Clinical prediction rules might be more accurate; however, they should be validated externally. Physicians should not restrict urine sampling to children with unexplained fever or other features suggestive of urinary tract infection.

Rates of hospitalization for urinary tract infections among medicaid-insured individuals by spina bifida status, Tennessee 2005-2013

BACKGROUND

Individuals with spina bifida are at increased risk for urinary tract infection (UTI), however there are few population-based investigations of the burden of UTI hospitalizations.

OBJECTIVE

We assessed rates and risk factors for UTI hospitalization in individuals with and without spina bifida.

METHODS

We conducted a retrospective cohort study to estimate rates of UTI hospitalization by spina bifida status. We included individuals enrolled in Tennessee Medicaid who lived in one of the Emerging Infections Program's Active Bacterial Surveillance counties between 2005 and 2013. Spina bifida was primarily defined and UTI hospitalizations were identified using International Classification of Diseases, Ninth Revision diagnoses. We also studied a subset without specific health conditions potentially associated with UTI. We used Poisson regression to calculate rate ratios (RR) of UTIs for individuals with versus without spina bifida, adjusting for race, sex and age group.

RESULTS

Over the 9-years, 1,239,362 individuals were included and 2,493 met criteria for spina bifida. Individuals with spina bifida had over a four-fold increased rate of UTI hospitalization than those without spina bifida-in the overall study population and in the subset without specific, high-risk conditions (adjusted rate ratios: 4.41, 95% confidence intervals: 3.03, 6.43) and (4.87, 95% CI: 2.99, 7.92), respectively. We detected differences in rates of UTI hospitalization by race and sex in individuals without spina bifida that were not seen among individuals with spina bifida.

CONCLUSIONS

Individuals with spina bifida had increased rates of UTI hospitalizations, and associated demographic patterns differed from those without spina bifida.

Bacteriuria in pregnancy varies with the ambiance: a retrospective observational study at a tertiary hospital in Doha, Qatar

Objectives To explore the influence of ambient temperature and humidity on significant bacteriuria (SB) and urinary bacterial isolates in pregnant women. Methods A retrospective observational study was conducted in the sole tertiary-care hospital in Doha, Qatar. A sample of 1588 pregnant women delivering between June 2012 and March 2013 was randomly selected. Meteorological variables including ambient average daily temperature and humidity were sourced from online meteorological data, and patient information such as demographic data, urine culture results and bacterial isolates were collected from patient files. The receptor operative curve (ROC) analysis was used to determine the cutoff for temperature and humidity. Statistical analyses of associations between SB and bacterial isolates with respect to the ambient temperature and humidity were performed using Pearson's correlation, the chi-square (χ2) test and the Kruskal-Wallis test. Results Of the 21.24% positive cultures, 11.25% had SB. SB showed a significant strong positive (r = +0.677, n = 17, P = 0.003) and moderate negative (r = -0.587, n = 17, P = 0.013) correlation with average monthly temperature and humidity, respectively, with doubling of rates noted with temperatures ≥35°C (11.3% vs. 3.6%; P < 0.0001) and humidity ≤50% (10.6% vs. 3.2%; P < 0.0001). Escherichia coli and Group B Streptococcus (GBS) were the most common isolates. Conclusion This is the first study in this region that demonstrates maternal risk with SB, with ambient temperatures of ≥35°C and humidity ≤50%. The effect of these variables on the growth of various urinary bacteria has also been shown.

Work-up of Pediatric Urinary Tract Infection

Pediatric urinary tract infection (UTI) costs the health care system more than $180 million annually, and accounts for more than 1.5 million clinician visits per year. Accurate and timely diagnosis of these infections is important for determining appropriate treatment and preventing long-term complications such as renal scarring, hypertension, and end-stage renal disease. After the first 12 months, girls are more likely to be diagnosed with a UTI. About half of boys with UTI are diagnosed within the first 12 months of life. Diagnosis of UTI is made based on history and examination findings and confirmed by urine testing.

Blood Groups in Infection and Host Susceptibility

Blood group antigens represent polymorphic traits inherited among individuals and populations. At present, there are 34 recognized human blood groups and hundreds of individual blood group antigens and alleles. Differences in blood group antigen expression can increase or decrease host susceptibility to many infections. Blood groups can play a direct role in infection by serving as receptors and/or coreceptors for microorganisms, parasites, and viruses. In addition, many blood group antigens facilitate intracellular uptake, signal transduction, or adhesion through the organization of membrane microdomains. Several blood groups can modify the innate immune response to infection. Several distinct phenotypes associated with increased host resistance to malaria are overrepresented in populations living in areas where malaria is endemic, as a result of evolutionary pressures. Microorganisms can also stimulate antibodies against blood group antigens, including ABO, T, and Kell. Finally, there is a symbiotic relationship between blood group expression and maturation of the gastrointestinal microbiome.

Pediatric urinary tract infection: does the evidence support aggressively pursuing the diagnosis?

The epidemiology of pediatric fever has changed considerably during the past 2 decades with the development of vaccines against the most common bacterial pathogens causing bacteremia and meningitis. The decreasing incidence of these 2 conditions among vaccinated children has led to an emphasis on urinary tract infection as a remaining source of potentially hidden infections in febrile children. Emerging literature, however, has led to questions about both the degree and nature of the danger posed by urinary tract infection in nonverbal children, whereas the aggressive pursuit of the diagnosis consumes resources and leads to patient discomfort, medical risks, and potential overdiagnosis. We review both early and emerging literature to examine the utility and efficacy of early identification and treatment of urinary tract infection in children younger than 24 months. We conclude that in well children of this age, it may be reasonable to withhold or delay testing for urinary tract infection if signs of other sources are apparent or if the fever has been present for fewer than 4 to 5 days.

Pediatric urinary tract infections

Urinary tract infections (UTIs) in children are commonly seen in the emergency department and pose several challenges to establishing the proper diagnosis and determining management. This article reviews pediatric UTI and addresses epidemiology, diagnosis, treatment, and imaging, and their importance to the practicing emergency medicine provider. Accurate and timely diagnosis of pediatric UTI can prevent short-term complications, such as severe pyelonephritis or sepsis, and long-term sequelae including scarring of the kidneys, hypertension, and ultimately chronic renal insufficiency and need for transplant.

Trends in hospitalization for pediatric pyelonephritis: a population based study of California from 1985 to 2006

PURPOSE

We examined trends in pediatric hospitalization for pyelonephritis from 1985 to 2006 and identified factors associated with admission.

MATERIALS AND METHODS

We performed a population based analysis of hospital discharges using the Office of Statewide Health Planning and Development database to evaluate trends in California regarding pediatric hospitalizations for pyelonephritis from 1985 to 2006. Multivariable logistic regression was performed to identify factors associated with admission for pyelonephritis.

RESULTS

A total of 46,300 children were hospitalized for pyelonephritis in California from 1985 to 2006. The overall rate of hospitalization for pyelonephritis increased by greater than 80%, from 17 per 100,000 children in the California population in 1985 to 31 per 100,000 in 2005. This change was primarily due to the nearly ninefold increase in pyelonephritis hospitalizations observed in children younger than 1 year, from 28 per 100,000 in 1985 to 238 per 100,000 in 2005. Among children younger than 1 year males without private insurance and of nonwhite race had increased odds of hospitalization, while females with private insurance and of Asian race had increased odds of hospitalization, compared with nonprivate insurance and white race, respectively.

CONCLUSIONS

A significant increase in hospital admissions for pyelonephritis, primarily in children younger than 1 year, occurred in California between 1985 and 2006. Further studies are needed to establish the cause of this striking increase and to determine why certain pediatric populations are at increased risk for hospitalization.

Population pharmacokinetics and pharmacodynamics in anesthesia, intensive care and pain medicine

PURPOSE OF REVIEW

Population modeling is a relatively new pharmacological discipline, the development of which has largely been stimulated by the need for accurate models for the pharmacokinetics and dynamics of anesthetic agents.

RECENT FINDINGS

Population-based modeling is now considered superior to older, more traditional modeling methods. Nonlinear mixed-effect modeling - a commonly used population-based modeling approach - estimates intraindividual and interindividual variability, limits the influence of outlying samples and individuals through the use of Bayesian statistical analysis, and provides a potential means of optimizing drug delivery regimens, especially when used to define pharmacokinetic-dynamic models for target-controlled infusion systems. In addition to being used for pharmacokinetic modeling, in which the influence of factors such as age, weight and illness can be studied, it is a powerful tool for the study of the influence of multiple factors on drug pharmacodynamics.

SUMMARY

Nonlinear mixed-effect population-based modeling has become the gold standard method of pharmacokinetic and pharmacodynamic analysis during new drug development and during subsequent pharmacological studies. Population-based modeling techniques have been applied to numerous aspects of drug delivery in anesthesia, intensive care and pain medicine.