Exosomes Secreted by Wharton's Jelly-Derived Mesenchymal Stem Cells Promote the Ability of Cell Proliferation and Migration for Keratinocyte.

Mesenchymal stem cells (MSCs) isolated from Wharton's jelly (WJ-MSCs) and adipose tissue (AD-MSCs) are alternative sources for bone marrow-derived MSCs. Owing to their multiple functions in angiogenesis, immune modulation, proliferation, migration, and nerve regeneration, MSC-derived exosomes can be applied in "cell-free cell therapy". Here, we investigated the functional protein components between the exosomes from WJ-MSCs and AD-MSCs to explain their distinct functions. Proteins of WJ-MSC and AD-MSC exosomes were collected and compared based on iTRAQ gel-free proteomics data. Results: In total, 1695 proteins were detected in exosomes. Of these, 315 were more abundant (>1.25-fold) in AD-MSC exosomes and 362 kept higher levels in WJ-MSC exosomes, including fibrinogen proteins. Pathway enrichment analysis suggested that WJ-MSC exosomes had higher potential for wound healing than AD-MSC exosomes. Therefore, we treated keratinocyte cells with exosomes and the recombinant protein of fibrinogen beta chain (FGB). It turned out that WJ-MSC exosomes better promoted keratinocyte growth and migration than AD-MSC exosomes. In addition, FGB treatment had similar results to WJ-MSC exosomes. The fact that WJ-MSC exosomes promoted keratinocyte growth and migration better than AD-MSC exosomes can be explained by their higher FGB abundance. Exploring the various components of AD-MSC and WJ-MSC exosomes can aid in their different clinical applications.

Analgesic Effect of Low-Level Laser Therapy before Heel Lance for Pain Management in Healthy Term Neonates: A Randomized Controlled Trial.

Currently, the prevention, assessment, and management of procedural pain in neonates continues to challenge clinicians and researchers. Objective. To investigate the analgesic effect of low-level laser therapy (LLLT) during heel lance compared to breast milk (BM) feeding in healthy term neonates. In this randomized controlled trial, healthy term neonates who underwent heel lance were randomly assigned to an LLLT or a BM group. The LLLT group received laser therapy to the heel lance site for 20 s before heel lance. The BM group received 5 mL expressed BM via a syringe before heel lance. The primary outcomes were behavioral responses. The secondary outcomes were physiological responses and levels of salivary cortisol and α-amylase. A total of 125 neonates were included, of whom 55 in the LLLT group and 59 in the BM group completed the study. There were no significant differences in latency to first cry and cry duration between the two groups. The squeeze time was significantly shorter in the LLLT group than in the BM group (p = 0.047). There were no significant differences in pain scores, heart rate, respiratory rate, oxygen saturation, and blood pressure before and after heel lance between the two groups. There were no significant differences in salivary cortisol and α-amylase levels in the LLLT group before and after heel lance; however, the differences were significant in the BM group. These findings suggest that the analgesic effect of LLLT is similar to that of BM during heel lance in healthy term neonates. LLLT has potential as an analgesic treatment.

An Association Between Pediatric Bronchiolitis and Atopic Dermatitis: A Multi-Institutional Electronic Medical Records Database Study From Taiwan.

Atopic dermatitis (AD) is triggered by many environmental factors. We sought to determine the relationship between birth weight, infectious diseases, and AD. This retrospective cohort study analyzed data from the CGR Database for the period 2004 through 2015 in Taiwan. All diseases were classified using the International Classification of Disease codes. Logistic regression adjusted for birth weights and comorbidities were analyzed by SAS (version 9.4). P < .05 were considered statistically significant. In children with AD, bronchiolitis was significantly associated with the development of AD, whether the patients were aged < 2 years (odds ratio [OR] = 1.497; P = .014) or ≥ 2 years (OR = 1.882; P = .022). There was also no difference in the association between AD and different birth weights. We conclude that AD is associated with a previous history of bronchiolitis in children, regardless of age (less than or greater than 2 years).

Salivary microbiome and asthma risk in children with orofacial defects.

BACKGROUND: Patients with congenital orofacial defects, cleft lip (CL), cleft palate (CP), and cleft lip and palate (CLP) have continuous exposure of the respiratory system to the microbiome from the oral environment, offering opportunities to develop mucosal immunity in the airway. This two-part study aims to analyze data on asthma occurrence in CL, CP, and CLP infants and the composition of the salivary microbiome, and to evaluate the oral microbiota and its association with the risk of developing childhood asthma. METHODS: Patient data from the research database of Chang Gung Memorial Hospital from 2004 to 2015 were retrospectively analyzed by multivariable regression. Diseases diagnoses were defined by ICD codes. Asthma must also meet the criteria for receiving selective ß2 agonistic or/and inhaled corticosteroid treatments twice within 1 year. Analysis of the saliva microbiome was performed prospectively from 2016 to 2020 in 10 healthy term infants and 10 CLP infants on postnatal 7th day, 1 month, and 6 months by next-generation sequencing. RESULTS: Asthma and nonasthma groups included 988 and 3952 patients, respectively. The incidence of asthma development was higher in patients with CP than in CL and CLP groups (aOR: 5.644, CI: 1.423-22.376). The species composition of the microbiome at 1 and 6 months was significantly different between infants with CLP and healthy infants. CONCLUSION: Children with orofacial defects have a higher risk of developing asthma with a possible contribution from oral microbiota in the early months of life.

Elevated Urinary Hepcidin Level and Hypoferremia in Infants with Febrile Urinary Tract Infection: A Prospective Cohort Study.

To evaluate the kinetics of serum and urinary hepcidin levels along with anemia-related parameters during the infection course of infants with febrile urinary tract infection (UTI), we enrolled febrile infants aged one to four months in this prospective study. Febrile patients with UTI were allocated into Escherichia coli (E. coli) or non-E. coli groups according to urine culture results. Septic workup, blood hepcidin, iron profile, urinalysis, and urinary hepcidin-creatinine ratio were collected upon admission and 3 days after antibiotic treatment. In total, 118 infants were included. On admission, the febrile UTI group showed a significant reduction in serum iron level and a significant elevation of urinary hepcidin-creatinine ratio compared to the febrile control counterpart. Moreover, urinary hepcidin-creatinine ratio had the highest odds ratio, 2.01, in logistics regression analysis. After 3 days of antibiotic treatment, hemoglobin and the urinary hepcidin-creatinine ratio were significantly decreased. Patients with an E. coli UTI had a significantly decreased urinary hepcidin-creatinine ratio after 3 days of antibiotics treatment, whereas the non-E. coli group showed insignificant changes. Our study suggested that the urinary hepcidin-creatinine ratio elevated during acute febrile urinary tract infection and significantly decreased after 3 days of antibiotics treatment, especially in E. coli UTI.

Maternal psychological distress in the early postpartum period during COVID-19 pandemic: a pilot study.

BACKGROUND: The coronavirus disease 2019 infection (COVID-19) pandemic is a new global outbreak disease. According to the Taiwan Centers for Diseases Control statement, hospitals had to change their corresponding measures to prevent the spread of COVID-19. The frequency of parental visits to the special care nursery was reduced from three times to once daily. Visiting was not permitted from April 4 to May 10, 2020, and rooming-in with healthy neonates was discontinued, which could increase maternal postpartum distress. Therefore, this study was conducted to determine whether COVID-19 prevention increased maternal psychological distress. METHODS: This prospective study used convenience sampling to enroll healthy mothers who had just delivered via normal spontaneous delivery. Based on the neonates' status and visiting times, mothers were grouped into no-rooming-in, rooming-in, no-visiting, and one-visit/day groups. Mothers' baseline characteristics were compared using the Chi-square or Fisher's exact test and t-test. Salivary cortisol levels and scores of Chinese versions of the Perceived Stress Scale (PSS) and State-Trait Anxiety Inventory were evaluated on postpartum days 1 and 3 and analyzed by one-way analysis of variance and a paired t-test. RESULTS: There were 16, 58, 28, and 47 women categorized as no-rooming-in, rooming-in, no-visit, and one-visit/day groups, respectively. No significant differences were found between groups in mothers' baseline characteristics and postpartum salivary cortisol levels. The PSS on day 3 was significantly higher than on day 1 in every group (p < 0.001). The PSS increasing trend in the no-rooming-in group was significantly greater than that in the no-visit group (p = 0.02) and significantly greater in the rooming-in group than that in the one-visit/day group (p = 0.001). CONCLUSION: Postpartum stress increased for all mothers and was an even more significant response to the COVID-19 pandemic than the stress associated with neonates' hospitalization.

The prenatal and postnatal effects of air pollution on asthma in children with atopic dermatitis.

OBJECTIVES: Air pollution is strongly associated with asthma, but has not been determined to induce new-onset asthma development in children with atopic dermatitis (AD). WORKING HYPOTHESIS: To assess whether prenatal/postnatal exposure to air pollutants triggers new-onset asthma development in children with AD. STUDY DESIGN: Retrospective cohort study. PATIENT-SUBJECT SELECTION: Data of patients 3% were significantly influenced by prenatal exposure to PM2.5 , especially SO2 , NO, and NO2 . CONCLUSIONS: Prenatal and postnatal exposure to air pollution have an association with asthma development in AD patients.

Echocardiographic Determination of Percutaneous Central Venous Catheters in the Superior Vena Cava: A Prospective Cohort Study.

Malposition of percutaneous central venous catheters (PCVCs) in the superior vena cava (SVC) is common. We previously showed that real-time sonography was safer and faster than radiography in identifying PCVC tip location in the inferior vena cava (IVC). However, in preterm infants, determining PCVC tip location in the SVC is complicated by endotracheal or nasogastric tubes in situ and emphysematous lung conditions. We aimed to find an appropriate sonographic view by which to assess PCVC tip location in the SVC compared to the sonographic examination of PCVC in the IVC. Neonates (n = 50) with PCVCs in the SVC were enrolled and their data (gestational age, gender, birth weight, body weight at intervention, repositioning rate, and duration of tip assessment) were compared with retrospective data of 50 neonates with PCVCs in the IVC. The mean gestational age in the groups of IVC and SVC was 31.43 weeks and 32.16 weeks, respectively. The mean birth weight in the groups of IVC and SVC was 1642.18 g and 1792.00 g, respectively. Placement of an S12-4 ultrasound sector transducer to obtain clear parasternal views of the aorta allows visualization of PCVC tips in the SVC and near the cavoatrial junction. PCVC repositioning rates were not significantly different between the two groups (p = 0.092). Sonography examinations in the SVC had a longer duration than those in the IVC (p < 0.001). Sonography provides an accurate method for determining PCVC tip location in the SVC.

Profile of Urinary Cytokines in Kawasaki Disease: Non-Invasive Markers.

This cohort study aimed to investigate urinary cytokines expression to help identify a less invasive method of cytokine detection for Kawasaki disease (KD). Patients with confirmed KD were recruited. Patients with fever or urinary tract infection (UTI) were enrolled as control groups. Urinary samples were collected before and 3 days after intravenous immunoglobulin (IVIG) treatment. The levels of cytokines were detected by MILLPLEX® MAP human multiplex assay. All cytokines, i.e., epidermal growth factor (EGF), interferon (IFN)-γ, interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-13, IL-17A, IL-33, interferon-gamma-induced protein (IP)-10, macrophage inflammatory protein (MIP)-1ß, tumor necrosis factor (TNF)-α, and vascular endothelial growth factor (VEGF) except monocyte chemoattractant protein (MCP)-1 were significantly higher in the KD group, compared with the fever-control (FC) group, whereas the expressions of IFN-γ, IL-1ß, IL-6, IL-8, IL-17A, IL-33, MCP-1, MIP-1ß, and TNF-α were significantly lower in the urine of KD patients, as compared with the UTI group. The expressions of EGF, IFN-γ, IL-8, IL-13, and IL-17A were higher in the urine of KD patients than in the FC group, whereas the level of IL-1ß was lower in KD than in the UTI group after age adjustment by logistic regression. Levels of IL-6, IL-8, IL-13, IP-10, and MCP-1 were significantly higher in the pre-IVIG urine of KD patients than in the post-IVIG treatment group. Additionally, urine IL-4 and blood C-reactive protein were higher in the KD group with coronary artery lesion (CAL) than in the non-CAL group. Results of this study provide a new view of urinary cytokine expression in the disease progress of KD, which may help clinicians to predict and prevent morbidity early and non-invasively.

Early Life Factors Associated with Preschool Wheezing in Preterm Infants.

Advanced neonatal care has increased the survival of neonates born prematurely, and prematurity is a well-known risk factor for asthma/wheezing disorders. Thus, this prospective study aimed to determine the early life factors associated with preschool wheezing in premature neonates. Preterm neonates born between 2012 and 2017 were recruited, excluding those with bacterial infection within 7 days of life, maternal sepsis, and maternal chorioamnionitis. Birth and admission history, comorbidities, and maternal history were documented. Respiratory problems were followed-up at the neonatal outpatient department. Patients were divided into wheezing and non-wheezing groups. Data were analyzed using the Mann-Whitney test and Fisher's exact test, and multivariable logistic regression was used to define the risk factors of preschool wheezing/asthma. A total of 125 preterm infants were enrolled, including 19 in the wheezing group and 106 in the non-wheezing group. Patients in the wheezing group had longer duration of intubation (p = 0.025), higher rates for exclusive breast milk feeding (p = 0.012), and higher re-hospitalization rates for respiratory tract infections (p < 0.001), especially for respiratory syncytial virus (RSV) bronchiolitis (p = 0.045). The incidence of allergic rhinitis was also higher in the wheezing group (p = 0.005). After multivariable logistic regression, allergic rhinitis and re-hospitalization for respiratory tract infections were two significant risk factors for preschool wheezing/asthma in premature neonates. Close follow-up of premature infants at high risk for asthma susceptibility is recommended.

Smoflipid Is Better Than Lipofundin for Long-Term Neurodevelopmental Outcomes in Preterm Infants.

Neurodevelopmental morbidities developed more commonly in low-birth-weight premature infants. We sought to determine the effects of different lipid emulsions on the neurodevelopmental outcomes of children born prematurely. This retrospective cross-sectional study had two intervention legs, Lipofundin® MCT/LCT (LIPO) versus Smoflipid® (SMOF), which are mainly differentiated by fish oil. Data of premature neonates born between 2001 and 2015 from the research database of Chang Gung Memorial Hospital with corresponding individual medical records up to July 2020 were analyzed. Long-term neurodevelopmental outcomes were defined by the international classification of disease codes -9 or -10. The prevalence of diseases was compared between LIPO and SMOF groups at five and five years old and further analyzed by stratification of 1500 g birth weight. The LIPO and SMOF groups each included 1120 neonates. Epilepsy, cerebral palsy, developmental disorder and attention-deficit hyperactivity disorder (ADHD) were significantly decreased at age two years in the SMOF group, and epilepsy, language delay (LD), ADHD and autism spectrum disorder (ASD) were significantly decreased in the SMOF group at age five years. In children with birth weight < 1500 g, ADHD was decreased in the SMOF group at ages two and five years, and ASD was decreased in the SMOF group at age five years. In children with birth weight ≥ 1500 g, epilepsy, LD and ADHD were decreased in the SMOF group at age two years. LD was decreased in the SMOF group at age five years. We conclude that lipid emulsions with fish oil improve the neurodevelopmental outcomes of children born prematurely.

Salivary cytokine - A non-invasive predictor for bronchopulmonary dysplasia in premature neonates.

BACKGROUND: To find a less invasive method of cytokine detection for premature neonates, we conducted this cohort study to investigate the salivary cytokines and to analyze their correlations with bronchopulmonary dysplasia (BPD). METHODS: Premature neonates younger than 34 weeks of gestational age without maternal or neonatal infection were recruited. Salivary samples were collected on their first (D1) and seventh (D7) days of life. The cytokine levels were detected by MILLPLEX® MAP Human multiplex assay. One-way analysis of variance, the Kruskal-Wallis test, Pearson's chi-square test, and logistic regression were used to analyze the data. RESULTS: Totally 125 neonates were enrolled and separated into four groups: control, mild, moderate, and severe BPD group. The salivary levels of D1 interleukin (IL)-6, IL-8, IL-10, IL-17, interferon (IFN)-γ, and D7 IL-6 (p = 0.001, 0.001, 0.000, 0.043, 0.037 and 0.001, respectively) were significantly higher in the BPD groups than in the control group. After adjusting for the gestational age, acid-base equivalent, and absolute neutrophil count, comparing to the control group, the levels of D7 IL-17 became significantly lower in all three BPD groups (p = 0.032, 0.030, and 0.030, respectively) and that of D7 IFN-α2 became significantly lower in the severe BPD group (p = 0.037). CONCLUSION: Early-life salivary cytokine levels were correlated with the development of BPD in premature neonates. This study provides a novel method to predict BPD early and non-invasively.

The effects of antibiotic exposure on asthma in children with atopic dermatitis.

Early-life antibiotic use is associated with allergic diseases. The risk factors for the progression from atopic dermatitis (AD) to asthma or allergic rhinitis are still unknown. We aimed to investigate the association between exposure to different antibiotics and the risk of new-onset asthma in children with AD. By using the Longitudinal Health Insurance Database 2005, we selected AD patients less than 6 years old identified by ICD-9-CM code 691.8. The case group was defined as those having new-onset asthma, and the control group was defined as those without an asthma history. Information on antibiotic exposure in the 5 years prior to the index date was collected from drug prescription records. We estimated the adjusted odds ratio by using conditional logistic regression, adjusted for age, sex, index year, other potential risk factors and antibiotics. Antibiotic exposure was associated with the development of asthma in patients with AD (aOR = 3.68, 95% CI 2.13-6.36), particularly for patients less than 5 years old (aOR = 4.14, 95% CI 2.24-7.64) (p for trend < 0.001), even though lower cumulative antibiotic defined daily doses (DDDs) were associated with new-onset asthma occurrence. Antibiotic exposure, especially macrolide exposure, is associated with an increased risk of asthma in patients with AD.

The appropriate frequency of dressing for percutaneous central venous catheters in preventing catheter-related blood stream infection in NICU - A randomized controlled trial.

BACKGROUND: Complications of percutaneous central venous catheters (PCVCs) include catheter-related blood stream infection (CRBSI), occlusion, leakage, and phlebitis, which may lead to sepsis or prolonged hospitalization. The primary objective of this randomized controlled trial was to determine the appropriate frequency of dressing for percutaneous central venous catheters in preventing CRBSI, every week regularly vs. non-regularly, in premature neonates in NICU. METHODS: Patients in NICU requiring PCVCs from March 2019-May 2020 were enrolled. Enrolled patients were randomly assigned into 2 groups: regular dressing group (RD), for which dressings were changed every week regularly, or additionally when oozing was noticed; and non-regular dressing group (ND), for which dressings were changed only when oozing was visible. The incidence of CRBSI, occlusion, leakage, and phlebitis were compared between the two groups using the Chi-squared test. The incidence of catheter-related complications was defined as numbers of episodes per 1000 catheter-days. RESULTS: A total of 197 PCVCs were enrolled. The ND and RD groups had 99 and 98 PCVCs, respectively. The average CD interval was 9.3 days in ND group and 5.8 days in RD group. The incidence of CRBSI in RD group was 0‰, which was significantly lower than that of ND group, which was 2.0‰ (p = 0.048), but no significant differences were found between groups in the incidence of occlusion, leakage, and phlebitis of PCVCs. CONCLUSION: Regular dressing changes every week and when oozing occurs while maintaining the protocol of maximum sterile barrier precautions is the best method and frequency of dressings of PCVCs.

The role of ultrasonography for detecting tip location of percutaneous central venous catheters in neonates-a single-center, prospective cohort study.

BACKGROUND: Percutaneous central venous catheters (PCVCs) are used commonly and widely in the neonatal intensive care unit (NICU). Malposition of PCVCs may cause life-threatening complications and prolong hospitalization. In Taiwan, conventional chest-abdomen radiography (CXR) has been used widely and routinely for assessing tip location of PCVCs. Compared to ultrasonography (US), CXR cannot provide real-time assessment, and patients are exposed to radiation. Therefore, this study aimed to analyze the role of US in detecting PCVC tip location in the lower extremities. METHODS: Neonates who received PCVC insertion in the lower extremities in NICU from March 2019 to April 2020 were enrolled in this prospective cohort study. PCVC tip location was confirmed finally by conventional CXR after US examination and patients were included in the sono group; those not assessed by US formed the non-sono group. In addition, PCVCs inserted in 2018 for which tip location was evaluated only by CXR, were reviewed retrospectively and these cases were included in the non-sono group. Withdrawal rates between the two groups were analyzed using Chi-square test. RESULTS: The sono group included 166 neonates with PCVCs and 141 were in the non-sono group. Median gestational age at date of PCVC insertion was 33.21 and 32.71 weeks in sono and non-sono groups, respectively (p = 0.37). Withdrawal rates were 10.84% and 65.95% (p < 0.001) and duration for catheter location confirmation were 2-4.75 min and 75-247.25 min (p < 0.001), respectively. CONCLUSION: US provides more reliable images than conventional radiography alone for identifying PCVC tip locations in the lower extremities. It can effectively reduce catheter insertion duration, and was associated with fewer manipulations.

A novel method to detect bacterial infection in premature infants: Using a combination of inflammatory markers in blood and saliva.

BACKGROUND: Opportunistic infection leads to high morbidity and mortality in premature babies due to their immature immune system. Biomarkers in blood have been reported to detect bacterial infection in neonates. However, serial blood exams pose iatrogenic anemia in premature babies. Thus, this study aimed to identify cytokines in saliva, which can help to diagnose bacterial infection in premature babies via a non-invasive method. METHODS: Premature neonates were enrolled from Aug. 2012 to Feb. 2015 after completing informed consent. Babies with congenital anomalies, bronchopulmonary dysplasia, necrotizing enterocolitis and any surgical indicated diseases were excluded. Salivary samples collection and septic work-up were performed when bacterial infection was clinically suspected, as well as one week after antimicrobial treatment. The level of salivary cytokines was detected by MILLPLEX® MAP and analyzed by Mann-Whitney U test. RESULTS: There were 16 episodes of bacterial infection in 10 cases. Culture-positive group had significantly higher levels of salivary Interleukin (IL) 6, IL-8, macrophage inflammatory protein (MIP)1α, MIP-1ß and tumor necrosis factor (TNF)-α than that in the culture-negative group (p = 0.002, 0.006, 0.001, <0.001, 0.009), and blood C-reactive protein and sugar as well (p < 0.001, 0.026). After adjusting postmenstrual age by logistic regression, blood sugar level was the most significant biomarker (p = 0.019). In combination of blood and salivary biomarkers, blood sugar higher than 67 mg/dL and salivary IL-6 higher than 367.25 pg/mL concurrently, would accurately detect bacterial infection in premature babies. CONCLUSION: This non-invasive method might help us to accurately diagnose bacterial infection in premature babies.

Diagnostic values of C-reactive protein and complete blood cell to identify invasive bacterial infection in young febrile infants.

BACKGROUND: Newborn infants younger than 3 months old with a fever are frequently evaluated for the risk of invasive bacterial infections (IBIs), which include bacteremia and/or bacterial meningitis, in the pediatric emergency department (PED). The purpose of this study was to determine the individual complete blood cell count and biochemistry levels associated with IBIs in febrile infants. METHODS: We carried out this retrospective study using a pediatric emergency department at a tertiary medical center in southern Taiwan, where we also evaluated the clinical characteristics and routine blood tests between experimental groups. RESULTS: We enrolled 1231 febrile infants under the age of 3 months old in this study. We found higher body temperature, neutrophil percentage, and C-Reactive protein (CRP) values and a lower hemoglobin level in the IBIs group. Furthermore, a CRP value greater than 25 mg/L can predict IBIs at a better rate than the group with values lower than 25 mg/L (11.7% vs. 2.1%, Odds ratio 6.3, p < 0.001). CONCLUSION: This study provides evidence that a CRP level greater than 25 mg/L can more accurately predict IBIs in febrile infants. Furthermore, lower hemoglobin levels were also found in IBIs. Nevertheless, additional laboratory tests are needed to identify young febrile infants with IBIs.

The equations of the inserted length of percutaneous central venous catheters on neonates in NICU.

BACKGROUND: In neonatal intensive care units, a percutaneous central venous catheter (PCVC) is inserted peripherally and threaded into a central venous location, when intravenous access is anticipated for an extended period of time. The tip location of PCVCs should be checked by an X-ray after the procedure. The present study aimed to determine an equation to estimate the optimal insertion length of PCVCs in neonates prior to the procedure. METHODS: The data of all neonates who had PCVC insertion between May 1st 2015 and April 30th 2016 was reviewed. Their gender, body weight and body length at the insertion date, any complications and the tip culture of their PCVCs were recorded. The tip location of the PCVC, which was confirmed by X-ray, was either in the inferior vena cava near to the diaphragm or in the superior vena cava before the right atrial junction, depending on the insertion site. We analyzed the correlation among inserted length of PCVCs, body weight and body length by linear regression to determine an equation for estimating the optimal insertion length of PCVCs. The accuracy of the equations was evaluated prospectively by Pearson's correlation analysis, and the adjusting rate of PCVCs after the initial insertion was compared between the traditional method and using the equation. RESULTS: The equation of PCVCs inserted in the foot was "insertion length (cm) = 16 + 4.27 × body weight (kg)", in the femoral vein was "inserted length (cm) = 9.8 + 1.7 × body weight (kg)", in the popliteal vein was "inserted length (cm) = -0.3 + 0.45 × body length (cm)", in the hand was "inserted length (cm) = 4.46 + 0.32 × body length (cm)", and in the axillary vein was inserted length (cm) = 1 + 0.18 × body length (cm). The adjusting rate of PCVCs after initial insertion was decreased from 73.5% to 53% following use of the equation. CONCLUSIONS: Equations provided a convenient and accurate method to estimate the optimal insertion length of PCVCs before their placement.