Prospective multicenter evaluation of adherence to the Dutch guideline for children aged 0-16 years with fever without a source-febrile illness in children (FINCH) study.

Evaluation of guidelines in actual practice is a crucial step in guideline improvement. A retrospective evaluation of the Dutch guideline for children with fever without an apparent source (FWS) showed 50% adherence in young infants. We prospectively evaluated adherence to the Dutch guideline and its impact on management in current practice. Prospective observational multicenter cross-sectional study, including children 3 days to 16 years old presented for FWS at one of seven emergency departments in participating secondary and tertiary care hospitals in the Netherlands. Adherence to the Dutch FWS guideline, adapted from the National Institute for Health and Care Excellence (NICE) guideline, was evaluated, and patterns in non-adherence and the impact of non-adherence on clinical outcomes and resource use were explored. Adherence to the guideline was 192/370 (52%). Adherence was lowest in patients categorized as high risk for severe infection (72/187, 39%), compared to the low-risk group (64/73, 88%). Differences in adherence were significant between risk categories (P < 0.001) but not between age categories. In case of non-adherence, less urinalysis, fewer bacterial cultures (blood, urine, and cerebral spinal fluid), and less empirical antibiotic treatment were performed (P < 0.050). Clinical outcomes were not significantly different between the non-adherence and the adherence group, particularly regarding missed severe infections. CONCLUSIONS: We found a high non-adherence rate of 48%, which did not lead to unfavorable clinical outcomes. This substantiates the need for a critical reevaluation of the FWS guideline and its indications for bacterial cultures, viral testing, and antibiotic treatment. WHAT IS KNOWN: • Despite the development of national guidelines, variation in practice is still substantial in the assessment of febrile children to distinguish severe infection from mild self-limiting disease. • Previous retrospective research suggests low adherence to national guidelines for febrile children in practice. WHAT IS NEW: • In case of non-adherence to the Dutch national guideline, similar to the National Institute for Health and Care Excellence (NICE) guideline from the United Kingdom, physicians have used fewer resources than the guideline recommended without increasing missed severe infections.

Barriers and Facilitators to the Implementation of the Early-Onset Sepsis Calculator: A Multicenter Survey Study.

Prior studies demonstrated the neonatal early-onset sepsis (EOS) calculator's potential in drastically reducing antibiotic prescriptions, and its international adoption is increasing rapidly. To optimize the EOS calculator's impact, successful implementation is crucial. This study aimed to identify key barriers and facilitators to inform an implementation strategy. A multicenter cross-sectional survey was carried out among physicians, residents, nurses and clinical obstetricians of thirteen Dutch hospitals. Survey development was prepared through a literature search and stakeholder interviews. Data collection and analysis were based on the Consolidated Framework for Implementation Research (CFIR). A total of 465 stakeholders completed the survey. The main barriers concerned the expectance of the department's capacity problems and the issues with maternal information transfer between departments. Facilitators concerned multiple relative advantages of the EOS calculator, including stakeholder education, EOS calculator integration in the electronic health record and existing positive expectations about the safety and effectivity of the calculator. Based on these findings, tailored implementation interventions can be developed, such as identifying early adopters and champions, conducting educational meetings tailored to the target group, creating ready-to-use educational materials, integrating the EOS calculator into electronic health records, creating a culture of collective responsibility among departments and collecting data to evaluate implementation success and innovation results.

A Cost Overview of Minimally Invasive Total Mesorectal Excision in Rectal Cancer Patients: A Population-based Cohort in Experienced Centres.

Background: Total mesorectal excision has been the gold standard for the operative management of rectal cancer. The most frequently used minimally invasive techniques for surgical resection of rectal cancer are laparoscopic, robot-assisted, and transanal total mesorectal excision. As studies comparing the costs of the techniques are lacking, this study aims to provide a cost overview. Method: This retrospective cohort study included patients who underwent total mesorectal resection between 2015 and 2017 at 11 dedicated centers, which completed the learning curve of the specific technique. The primary outcome was total in-hospital costs of each technique up to 30 days after surgery including all major surgical cost drivers, while taking into account different team approaches in the transanal approach. Secondary outcomes were hospitalization and complication rates. Statistical analysis was performed using multivariable linear regression analysis. Results: In total, 949 patients were included, consisting of 446 laparoscopic (47%), 306 (32%) robot-assisted, and 197 (21%) transanal total mesorectal excisions. Total costs were significantly higher for transanal and robot-assisted techniques compared to the laparoscopic technique, with median (interquartile range) for laparoscopic, robot-assisted, and transanal at €10,556 (8,642;13,829), €12,918 (11,196;16,223), and € 13,052 (11,330;16,358), respectively (P < 0.001). Also, the one-team transanal approach showed significant higher operation time and higher costs compared to the two-team approach. Length of stay and postoperative complications did not differ between groups. Conclusion: Transanal and robot-assisted approaches show higher costs during 30-day follow-up compared to laparoscopy with comparable short-term clinical outcomes. Two-team transanal approach is associated with lower total costs compared to the transanal one-team approach.

Reactions to peanut at first introduction in infancy are associated with age ≥8 months and severity of eczema.

BACKGROUND: Previous studies have shown the efficacy of the early introduction of peanut to prevent peanut allergy. Due to the exclusion of infants with sensitization to peanut, it remains unclear what the optimal timing of introduction is. METHODS: The PeanutNL study was performed in 6 pediatric allergology centers in the Netherlands. Infants referred for the clinical early introduction of peanut to prevent peanut allergy underwent skin prick tests for peanut and an oral peanut challenge at a median age of 6 months. RESULTS: One hundred sixty two of 707 infants (23%) who had never eaten peanut before were sensitized to peanut, of which 80 (49%) had wheals of >4 mm. Sixty seven of 707 infants (9.5%) had a positive oral challenge to peanut at first introduction. Multivariate analysis revealed that age (p < .001) and SCORAD eczema severity scores (p = .001) were significant risk factors. Introduction of peanut at ≥8 months in infants with moderate and severe eczema resulted in an increased risk (odds ratio 5.24 (p = .013) and 3.61 (p = .019), respectively) of having reactions to peanut as compared to introduction before 8 months. A family history of peanut allergy and previous reactions to egg were not identified as independent risk factors. CONCLUSION: These results suggest that peanut should be introduced before the age of 8 months to reduce the risk of reactions at first exposure in infants with moderate and severe eczema. Furthermore, since children with severe eczema have the highest risk of reactions, the clinical introduction of peanut should be considered, at the latest at the age of 7 months.

Implications of the new MRI-based rectum definition according to the sigmoid take-off: multicentre cohort study.

BACKGROUND: The introduction of the sigmoid take-off definition might lead to a shift from rectal cancers to sigmoid cancers. The aim of this retrospective cohort study was to determine the clinical impact of the new definition. METHODS: In this multicentre retrospective cohort study, patients were included if they underwent an elective, curative total mesorectal excision for non-metastasized rectal cancer between January 2015 and December 2017, were registered in the Dutch Colorectal Audit as having a rectal cancer according to the previous definition, and if MRI was available. All selected rectal cancer cases were reassessed using the sigmoid take-off definition. The primary outcome was the number of patients reassessed with a sigmoid cancer. Secondary outcomes included differences between the newly defined rectal and sigmoid cancer patients in treatment, perioperative results, and 3-year oncological outcomes (overall and disease-free survivals, and local and systemic recurrences). RESULTS: Out of 1742 eligible patients, 1302 rectal cancer patients were included. Of these, 170 (13.1 per cent) were reclassified as having sigmoid cancer. Among these, 93 patients (54.7 per cent) would have been offered another adjuvant or neoadjuvant treatment according to the Dutch guideline. Patients with a sigmoid tumour after reassessment had a lower 30-day postoperative complication rate (33.5 versus 48.3 per cent, P < 0.001), lower reintervention rate (8.8 versus 17.4 per cent, P < 0.007), and a shorter length of stay (a median of 5 days (i.q.r. 4-7) versus a median of 6 days (i.q.r. 5-9), P < 0.001). Three-year oncological outcomes were comparable. CONCLUSION: Using the anatomical landmark of the sigmoid take-off, 13.1 per cent of the previously classified patients with rectal cancer had sigmoid cancer, and 54.7 per cent of these patients would have been treated differently with regard to neoadjuvant therapy or adjuvant therapy.

Impact of a diverting ileostomy in total mesorectal excision with primary anastomosis for rectal cancer.

BACKGROUND: The role of diverting ileostomy in total mesorectal excision (TME) for rectal cancer with primary anastomosis is debated. The aim of this study is to gain insight in the clinical consequences of a diverting ileostomy, with respect to stoma rate at one year and stoma-related morbidity. METHODS: Patients undergoing TME with primary anastomosis for rectal cancer between 2015 and 2017 in eleven participating hospitals were included. Retrospectively, two groups were compared: patients with or without diverting ileostomy construction during primary surgery. Primary endpoint was stoma rate at one year. Secondary endpoints were severity and rate of anastomotic leakage, overall morbidity rate within thirty days and stoma (reversal) related morbidity. RESULTS: In 353 out of 595 patients (59.3%) a diverting ileostomy was constructed during primary surgery. Stoma rate at one year was 9.9% in the non-ileostomy group and 18.7% in the ileostomy group (p = 0.003). After correction for confounders, multivariate analysis showed that the construction of a diverting ileostomy during primary surgery was an independent risk factor for stoma at one year (OR 2.563 (95%CI 1.424-4.611), p = 0.002). Anastomotic leakage rate was 17.8% in the non-ileostomy group and 17.2% in the ileostomy group (p = 0.913). Overall 30-days morbidity rate was 37.6% in the non-ileostomy group and 56.1% in the ileostomy group (p < 0.001). Stoma reversal related morbidity rate was 17.9%. CONCLUSIONS: The stoma rate at one year was higher in patients with ileostomy construction during primary surgery. The incidence and severity of anastomotic leakage were not reduced by construction of an ileostomy. The morbidity related to the presence and reversal of a diverting ileostomy was substantial.

Comparison of three-year oncological results after restorative low anterior resection, non-restorative low anterior resection and abdominoperineal resection for rectal cancer.

INTRODUCTION: Oncological outcome might be influenced by the type of resection in total mesorectal excision (TME) for rectal cancer. The aim was to see if non-restorative LAR would have worse oncological outcome. A comparison was made between non-restorative low anterior resection (NRLAR), restorative low anterior resection (RLAR) and abdominoperineal resection (APR). MATERIALS AND METHODS: This retrospective cohort included data from patients undergoing TME for rectal cancer between 2015 and 2017 in eleven Dutch hospitals. A comparison was made for each different type of procedure (APR, NRLAR or RLAR). Primary outcome was 3-year overall survival (OS). Secondary outcomes included 3-year disease-free survival (DFS) and 3-year local recurrence (LR) rate. RESULTS: Of 998 patients 363 underwent APR, 132 NRLAR and 503 RLAR. Three-year OS was worse after NRLAR (78.2%) compared to APR (86.3%) and RLAR (92.2%, p < 0.001). This was confirmed in a multivariable Cox regression analysis (HR 1.85 (1.07, 3.19), p = 0.03). The 3-year DFS was also worse after NRLAR (60.3%), compared to APR (70.5%) and RLAR (80.1%, p < 0.001), HR 2.05 (1.42, 2.97), p < 0.001. The LR rate was 14.6% after NRLAR, 5.2% after APR and 4.8% after RLAR (p = 0.005), HR 3.22 (1.61, 6.47), p < 0.001. CONCLUSION: NRLAR might be associated with worse 3-year OS, DFS and LR rate compared to RLAR and APR.

Current treatment practice of functional abdominal pain disorders in children: A multicenter survey.

BACKGROUND: Approximately 90% of the children with chronic abdominal pain are diagnosed as having functional abdominal pain disorder (FAPD). The Dutch guideline "functional abdominal pain" provides a stepwise approach to treat FAPD. The aim of this survey was twofold first, to determine adherence to the Dutch guideline, and second to determine current management of FAPDs in clinical practice. METHODS: A multicenter survey was designed. The survey was sent to pediatricians and pediatric residents in December 2020. The study ran from October 2020 until March 2021. Participants in ten hospitals in the western region of The Netherlands were invited to complete this survey. Respondents who indicated not to treat children with FAPDs or respondents who completed less than 3 steps of the survey were excluded. RESULTS: In total, 85/174 (48.9%) respondents completed the survey. We included 80 respondents, 68 pediatricians and 12 pediatric residents, for analysis. Overall, self-reported guideline adherence was 85%. Self-reported adherence was higher than actual adherence. Only 50% of all respondents followed the first three steps of the guideline. The reported non-pharmacological and pharmacological treatments were diverse and varied between different age groups. The average follow-up duration was between 2 and 6 months, and the most regularly used outcome measures were attendance at school, quality of life, and adequate pain relief/reassurance. CONCLUSION: We reportedly observed a large variation in the management of children with FAPDs, due to low guideline adherence among clinicians. Improved guideline adherence may be accomplished by updating the guideline with specific recommendations per subtype, follow-up and outcome measures as well measures to improve guideline implementation.

[A girl with dyspnea and an enlarged liver]. / Een meisje met dyspneu en een vergrote lever.

BACKGROUND: During winter, the influenza and Respiratory Syncytial Virus season, children are often seen in the emergency department with fever and respiratory symptoms. CASE DESCRIPTION: We describe the case of a 2-year-old girl with fever, dyspnea and signs of heart failure during physical examination. Echocardiogram showed a large amount of pericardial effusion with signs of cardiac tamponade. Pericardiocentesis showed 200 ml purulent liquid. Surgical drainage was performed. However pericardial effusion recurred. Because constrictive pericarditis was feared, a pericardiectomy was performed after which the patient recovered. Cultures showed Haemophilus influenzae type b and the patient was treated with amoxicillin for 4 weeks in total. CONCLUSION: Fever and dyspnea may also be caused by a problem outside the respiratory system. With physical examination a cardiac cause, such as pericarditis, can be detected. An ECG is easily obtained and can help in the differential diagnosis. An echocardiogram can confirm the diagnosis.

The learning curve of transanal total mesorectal excision for rectal cancer is associated with local recurrence: results from a multicentre external audit.

AIM: Transanal total mesorectal excision (TaTME) has been suggested as a potential solution for the resection of challenging mid and low rectal cancer. This relatively complex procedure has been implemented in many centres over the last years, despite the absence of long-term safety data. Recently, concern has arisen because of an increase in local recurrence in the implementation phase. The aim of this study was to assess the correlation between accumulated experience and local recurrences. METHOD: An independent clinical researcher performed an external audit of consecutive series of all TaTME procedures in six centres in the Netherlands. Kaplan-Meier estimated local recurrence rates were calculated and multivariate Cox proportional hazards regression analysis performed to assess risk factors for local recurrence. Primary outcome was the local recurrence rate in the initial implementation (cases 1-10), continued adoption (cases 11-40) and prolonged experience (case 41 onward). RESULTS: Six hundred and twenty-four consecutive patients underwent TaTME for rectal cancer with a median follow-up of 27 months (range 1-82 months). The estimated 2- and 3-year local recurrence rates were 4.6% and 6.6%, respectively. Cox proportional hazards regression revealed procedural experience to be an independent factor in multivariate analysis next to advanced stage (ycMRF+, pT3-4, pN+) and pelvic sepsis. Corrected analysis projected the 3-year local recurrence rates to be 9.7%, 3.3% and 3.5% for the implementation, continued adoption and prolonged experience cohorts, respectively. CONCLUSION: This multicentre study shows a high local recurrence rate (12.5%) after implementation of TaTME which lowers to an acceptable rate (3.4%) when experience increases. Therefore, intensified proctoring and further precautions must be implemented to reduce the unacceptably high risk of local recurrence at units starting this technique.

Implementation of robot-assisted total mesorectal excision by multiple surgeons in a large teaching hospital: Morbidity, long-term oncological and functional outcome.

BACKGROUND: Robot-assisted total mesorectal excision (TME) might offer benefits in less morbidity, better functional and long-term outcome over laparoscopic TME. METHODS: All consecutive patients undergoing robot-assisted TME for rectal cancer during implementation between May 2015 and December 2019 performed by five surgeons in a single centre were included. Outcomes included local recurrence rate at 3 years, conversion rate, circumferential resection margin (CRM) positivity rate, 30-day postoperative morbidity and outcomes of low anterior resection syndrome (LARS) questionnaires. RESULTS: In 105 robot-assisted TME, local recurrence rate at 3 years was 7.4%, conversion to open surgery rate was 8.6%, CRM positivity rate was 5.7%, 73.3% had good quality specimen, postoperative morbidity rate was 47.6% and anastomotic leakage rate was 9.0%. Incidence of major LARS was 55.3%. CONCLUSIONS: results of this study described acceptable morbidity, functional and long-term outcome during implementation of robotic TME for rectal cancer by multiple surgeons in a single centre.

Fever Without an Apparent Source in Young Infants: A Multicenter Retrospective Evaluation of Adherence to the Dutch Guidelines.

BACKGROUND: The Dutch fever without an apparent source (FWS) guidelines were published to timely recognize and treat serious infections. We determined the adherence to the Dutch FWS guidelines and the percentage of serious infections in infants younger than 3 months of age. Second, we identified which clinical criteria, diagnostic tests, and management were associated with nonadherence to the guidelines. METHODS: A retrospective cohort study was performed in 2 Dutch teaching hospitals. We assessed the charts of all infants with FWS who presented at the emergency departments from September 30, 2017, to October 1, 2019. Diagnostic and therapeutic decisions were compared with the recommendations, as published in the Dutch guidelines. Infants were categorized into the nonadherence group in case 1 or more recommendations were not adhered to. RESULTS: Data on 231 infants were studied; 51.5% of the cases adhered to the Dutch guidelines and 16.0% suffered from a serious infection. The percentage of infants with a serious infection was higher in the adherence compared with the nonadherence group. We observed no relevant differences in clinical outcomes. Univariate regression analysis showed that an abnormal white blood cell count was associated with nonadherence (OR 0.4, P = 0.049). Not obtaining a urine and blood culture and not starting intravenous antibiotic treatment were the most frequent reasons for nonadherence to the guidelines. CONCLUSIONS: Our study indicates that there was nonadherence in a large proportion of FWS cases. The guidelines may need to be adjusted to increase adherence.

Long-term oncological results after transanal total mesorectal excision for rectal carcinoma.

BACKGROUND: Transanal total mesorectal excision (TaTME) for mid and low rectal cancer has been shown to improve short-term outcomes, mostly due to lower conversion rates and with improved quality of the specimen. However, robust long-term oncological data supporting the encouraging clinical and pathological outcomes are lacking. METHODS: All consecutive patients undergoing TaTME with curative intent for mid or low rectal cancer in two referral centers in The Netherlands between January 2012 and April 2016 with a complete and minimum follow-up of 36 months were included. The primary outcome was local recurrence rate. Secondary outcomes were disease-free survival, overall survival and development of metastasis. RESULTS: There were 159 consecutive patients. Their mean age was 66.9 (10.2) years and 66.7% of all patients were men. Pathological analysis showed a complete mesorectum in 139 patients (87.4%), nearly complete in 16 (10.1%) and an incomplete mesorectum in 4 (2.5%). There was involvement of the CRM (< 1 mm) in one patient (0.6%) and no patients had involvement of the distal margin (< 5 mm). Final postoperative staging after neoadjuvant therapy was stage 0 in 11 patients (6.9%), stage I in 73 (45.9%), stage II in 31 (19.5%), stage III in 37 (23.3%) and stage IV in 7 (4.4%). The 3-year local recurrence rate was 2.0% and the 5-year local recurrence rate was 4.0%. Median time to local recurrence was 19.2 months. Distant metastases were found in 22 (13.8%) patients and were diagnosed after a median of 6.9 months (range 1.1-50.4) months. Disease-free survival was 92% at 3 years and 81% at 5 years. Overall survival was 83.6% at 3 years and 77.3% at 5 years. CONCLUSIONS: The long-term follow-up of the current cohort confirms the oncological safety and feasibility of TaTME in two high volume referral centers for rectal carcinoma. However, further robust and audited data must confirm current findings before widespread implementation of TaTME.

The Efficacy of an Ultrapure Alginate Gel in Reducing Adhesion Formation in a Rat Model of Blood Contamination.

BACKGROUND: Formation of peritoneal adhesions is the most frequent complication of abdominal and pelvic surgery and comprises a lifelong risk of adhesion-related morbidity and mortality. Some of the existing antiadhesive barriers are less effective in the presence of blood. In this study, we investigate the efficacy and safety of ultrapure alginate gel in the presence of blood. METHODS: In experiment 1 (30 rats), 1 mL ultrapure alginate gel was compared with no intervention in a model of cecal abrasion and persisting peritoneal bleeding by incision of the epigastric artery. In experiment 2 (30 rats), 2 mL ultrapure alginate gel was compared with no intervention in a model where a 1 mL blood clot was instilled intra-abdominally and a cecal resection was performed. The primary endpoint was the incidence and severity of adhesions after 14 d. RESULTS: In experiment 1, seven of 15 rats in the experimental group had intra-abdominal adhesions compared with 13 of 15 rats in the control group (P = 0.05); 3 of 15 rats had adhesions at the site of injury compared with 12 of 15 rats in the control group (P < 0.01). The severity and extent of adhesions was also reduced (P < 0.01). In experiment 2, 12 of 13 rats had adhesions compared with 13 of 14 rats in the control group (P = 1.00). CONCLUSIONS: Ultrapure alginate gel reduces the incidence and severity of adhesion in the presence of persisting bleeding, but not in a model of cecal resection and blood clot.

Perinatal Outcomes in Vertically Infected Neonates During a Chikungunya Outbreak on the Island of Curaçao.

Recent outbreaks of Chikungunya virus (CHIKV) infection confirm the vulnerability of neonates after vertical transmission. In 2014, CHIKV was reported for the first time in the Americas, including the island of Curaçao. We describe the outcomes of symptomatic neonates with vertically transmitted CHIKV infection during the CHIKV epidemic, who were admitted in the Saint Elisabeth Hospital, Willemstad, Curaçao. There were three symptomatic neonates with serologically confirmed infection. Two neonates developed neurological complications, including convulsions and intracerebral bleeding. One newborn, in whom maternal infection occurred 7 weeks before delivery, had a fatal outcome after birth. Maternal-fetal transmission of CHIKV may cause severe neonatal complications. There is a need to share experiences and to implement protocols toward the management of perinatal CHIKV infection.

Quality of life, functional status and adhesiolysis during elective abdominal surgery.

BACKGROUND: Adhesiolysis during abdominal surgery can cause iatrogenic organ injury, increased operative time and a more complicated convalescence. We assessed the impact of adhesiolysis and adhesiolysis-related complications on quality of life and functional status following elective abdominal surgery. METHODS: Prospective cohort study, comparing patients requiring and not requiring adhesiolysis during an elective laparotomy or laparoscopy using the SF-36 and DASI questionnaire scores. RESULTS: 518 patients were included. Pre- and postoperative quality of life did not significantly differ between both groups. Patients with adhesiolysis had a significantly lower pre- and postoperative functional status (p < 0.01). Higher age, concomitant pulmonary disease, postoperative complications, readmissions and chronic abdominal pain 6 months after surgery were all associated with a significant and independent decline in quality of life and functional status six months after surgery. CONCLUSION: Adhesiolysis in itself does not affect functional status and quality of life six months after surgery. Postoperative complications, readmissions and chronic abdominal pain are associated with a lower health status.

Development and implementation of a clinical pathway for cardiac surgery in the intensive care unit: Effects on protocol adherence.

RATIONALE, AIMS AND OBJECTIVES: Cardiac surgery (CS) is facilitated by multiple perioperative guidelines and protocols. Use of a clinical pathway (CP) may facilitate the care of these patients. METHODS: This is a pre-post design study in the ICU of a tertiary referral centre. A CP for CS patients in the ICU was developed by ICU-nurses and enabled them to execute proactively predefined actions in accordance with and within the preset boundaries which were part of a variance report. A tailored implementation strategy was used. Primary outcome measure was protocol adherence above 80% on the domains of blood pressure control, action on chest tube blood loss and electrolyte control within the CP. RESULTS: In a 4-month period, 84 consecutive CP patients were included and compared with 162 matched control patients admitted in the year before implementation; 3 patients were excluded. Propensity score was used as matching parameter. CP patients were more likely to receive early adequate treatment for derangements in electrolytes (96% vs 47%, P < .001), blood pressure (90% vs 49%, P < .001) and adequate treatment for chest tube blood loss (90% vs 10%, P < .001). We found no differences in hospital and ICU LOS, ICU readmission or mortality. CONCLUSION: Use of the CP improved postoperative ICU treatment for cardiac surgical patients. Implementation of a CP and the use of a special variance report could be a blueprint for the implementation and use of a CP in low-volume high complex surgery.

Optimization-Based Sensor Fusion of GNSS and IMU Using a Moving Horizon Approach.

The rise of autonomous systems operating close to humans imposes new challenges in terms of robustness and precision on the estimation and control algorithms. Approaches based on nonlinear optimization, such as moving horizon estimation, have been shown to improve the accuracy of the estimated solution compared to traditional filter techniques. This paper introduces an optimization-based framework for multi-sensor fusion following a moving horizon scheme. The framework is applied to the often occurring estimation problem of motion tracking by fusing measurements of a global navigation satellite system receiver and an inertial measurement unit. The resulting algorithm is used to estimate position, velocity, and orientation of a maneuvering airplane and is evaluated against an accurate reference trajectory. A detailed study of the influence of the horizon length on the quality of the solution is presented and evaluated against filter-like and batch solutions of the problem. The versatile configuration possibilities of the framework are finally used to analyze the estimated solutions at different evaluation times exposing a nearly linear behavior of the sensor fusion problem.