Clinical Focus

  • Anesthesia
  • Pediatric Anesthesia
  • Pediatric Cardiac Anesthesia

Academic Appointments

Professional Education

  • Fellowship: University Children's Hospital Zurich (2012) Switzerland
  • Board Certification: Swiss Medical Federation FMH, Anesthesia (2014)
  • Fellowship: University Hospital Zurich Anesthesiology Training (2014) Switzerland
  • Residency: Kantonsspital St Gallen Anesthesiology Training (2011) Switzerland
  • Internship: Kantonsspital St Gallen Surgery Training (2008) Switzerland
  • Medical Education: Justus Liebig Universitat (2007) Germany

Clinical Trials

  • Effects of Different Tidal Volume Ventilation Strategies on Fontan Flow and Hemodynamics Recruiting

    In patients with Fontan circulation blood is not pumped to the lungs from a ventricle. Instead the superior vena cava and inferior vena cava is connected to the pulmonary artery and blood flow to the lungs occurs passively along this Fontan pathway. This passive blood flow to the lungs occurs best when the patient is breathing on their own (spontaneous ventilation). However for certain surgeries and procedures patients need to have an endotracheal tube inserted and need to be muscle relaxed and receive positive pressure ventilation. Prior studies have shown that positive pressure ventilation can reduce blood flow to the lungs and consequently blood returning to the heart resulting in less blood pumped out to the rest of the body (cardiac output). The purpose of this study is to investigate if changing the volume of the positive pressure ventilation (tidal volume) affects blood flow to the lungs and cardiac output in patients with Fontan circulation.

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All Publications

  • Pre-operative fasting in children: A guideline from the European Society of Anaesthesiology and Intensive Care. European journal of anaesthesiology Frykholm, P., Disma, N., Andersson, H., Beck, C., Bouvet, L., Cercueil, E., Elliott, E., Hofmann, J., Isserman, R., Klaucane, A., Kuhn, F., de Queiroz Siqueira, M., Rosen, D., Rudolph, D., Schmidt, A. R., Schmitz, A., Stocki, D., Sumpelmann, R., Stricker, P. A., Thomas, M., Veyckemans, F., Afshari, A. 2022; 39 (1): 4-25


    Current paediatric anaesthetic fasting guidelines have recommended conservative fasting regimes for many years and have not altered much in the last decades. Recent publications have employed more liberal fasting regimes with no evidence of increased aspiration or regurgitation rates. In this first solely paediatric European Society of Anaesthesiology and Intensive Care (ESAIC) pre-operative fasting guideline, we aim to present aggregated and evidence-based summary recommendations to assist clinicians, healthcare providers, patients and parents. We identified six main topics for the literature search: studies comparing liberal with conservative regimens; impact of food composition; impact of comorbidity; the use of gastric ultrasound as a clinical tool; validation of gastric ultrasound for gastric content and gastric emptying studies; and early postoperative feeding. The literature search was performed by a professional librarian in collaboration with the ESAIC task force. Recommendations for reducing clear fluid fasting to 1 h, reducing breast milk fasting to 3 h, and allowing early postoperative feeding were the main results, with GRADE 1C or 1B evidence. The available evidence suggests that gastric ultrasound may be useful for clinical decision-making, and that allowing a 'light breakfast' may be well tolerated if the intake is well controlled. More research is needed in these areas as well as evaluation of how specific patient or treatment-related factors influence gastric emptying.

    View details for DOI 10.1097/EJA.0000000000001599

    View details for PubMedID 34857683

  • Bronchopulmonary Dysplasia. Paediatric anaesthesia Schmidt, A. R., Ramamoorthy, C. 2021


    Bronchopulmonary dysplasia is the most frequent adverse outcome of prematurity. Before implementation of antenatal steroids and surfactant therapy bronchopulmonary dysplasia was mostly characterized by fibrotic, scarred and hyper-inflated lungs due to pulmonary injury following mechanical ventilation and oxygen toxicity. With advances in neonatal medicine this "old" bronchopulmonary dysplasia has changed to a "new" bronchopulmonary dysplasia characterized by an arrest in lung growth, leading to alveolar simplification and pulmonary vascular dysangiogenesis. While the old definition was based on the need for oxygen supplementation at a postnatal age of 28 days or at a corrected gestational age of 36 weeks, the newer definition looks at the mode of respiratory support required (e.g., invasive versus non-invasive) and then graded as mild, moderate or severe. Patients with bronchopulmonary dysplasia may present with significantly impaired pulmonary function, reactive airways disease or exercise intolerance. Over time these patients may develop asthma or chronic obstructive pulmonary disease. The most serious long term complication is the development of pulmonary vascular disease and pulmonary hypertension. Medical treatment often includes diuretics, steroids, bronchodilators or oxygen supplementation and in the presence of pulmonary hypertension medication to decrease the pulmonary vascular resistance. Perioperative anesthetic risk is increased in children with pulmonary hypertension. These patients might require additional diagnostic imaging and plans for increased resource allocation such as post-operative intensive care admission.

    View details for DOI 10.1111/pan.14365

    View details for PubMedID 34877749

  • Pre-operative fasting times for clear liquids at a tertiary children's hospital; what can be improved? Anesthesia and pain medicine Schmidt, A. R., Fehr, J., Man, J., D'Souza, G., Wang, E., Claure, R., Mendoza, J. 2021


    Background: The goal of preoperative fasting is to prevent pulmonary aspiration during general anesthesia. Fasting times are often prolonged leading to patient discomfort and risk for adverse events. This retrospective quality improvement survey evaluated effective nil-per-os (NPO) times and causes for prolonged NPO times with the aim to suggest improvement strategies by a newly founded fasting task force.Methods: Data from all electronic anesthesia records from 2019 at our institution were reviewed for fasting times. Our NPO instructions follow American Society of Anesthesiology guidelines and are calculated based on the patient's arrival time (90 min before operating room [OR] time). Primary outcome was the effective NPO time for clear liquids, secondary outcomes were incidence of delays and the parental compliance with the NPO instructions. Data are presented as median (interquartile range).Results: In total 9,625 cases were included in the analysis. NPO time was documented in 72.1% with a median effective NPO time of 7:13 h (7:36). OR in room times were documented in 72.8%, 2,075 (29.5%; median time 0:10 h [0:21]) were earlier and 4,939 (70.5%; median time 0:29 h [0:54]) were later than scheduled. Parental NPO compliance showed a median deviation for clear liquid intake of 0:55 h (8:30).Conclusions: This study revealed that effective NPO times were longer than current ASA guidelines. Contributing causes include case delays and parental non-compliance to NPO instructions. Thus, task force recommendations include change NPO instruction calculations to scheduled OR time versus arrival time, and encourage parents to give their child clear liquids at the instructed time.

    View details for DOI 10.17085/apm.21025

    View details for PubMedID 34289299

  • Augmented Reality Visualization Tool For The Future of Tactical Combat Casualty Care. The journal of trauma and acute care surgery Leuze, C., Zoellner, A., Schmidt, A. R., Fischer, M. J., Cushing, R. E., Joltes, K., Zientara, G. P. 2021


    The objective of this project was to identify and develop software for an Augmented Reality (AR) application that runs on the US Army Integrated Visual Augmentation System (IVAS) to support a medical caregiver during training and combat casualty care (TC3) scenarios. In this AR-TC3 application, human anatomy of individual soldiers obtained pre-deployment is superimposed on the view of an injured warfighter through the IVAS. This offers insight into the anatomy of the injured warfighter to advance treatment in austere environments.In this article, we describe various software components required for an AR-TC3-tool. These include a body pose tracking system to track the patient's body pose, a virtual rendering of a human anatomy avatar, speech input to control the application and rendering techniques to visualize the virtual anatomy and treatment information on the AR display. We then implemented speech commands and visualization for four common medical scenarios including injury of a limb, a blast to the pelvis, cricothyrotomy, and a pneumothorax on the Microsoft Hololens 1.The software is designed for a forward surgical care tool on the US Army IVAS, with the intention to provide the medical caregiver with a unique ability to quickly assess affected internal anatomy. The current software components still had some limitations with respect to speech recognition reliability during noise and body pose tracking. These will likely be improved with the improved hardware of the IVAS, which is based on a modified Hololens 2.LEVEL OF EVIDENCE: Basic science paper.

    View details for DOI 10.1097/TA.0000000000003263

    View details for PubMedID 33938509

  • Impact of Modified Anesthesia Management for Pediatric Patients With Williams Syndrome. Journal of cardiothoracic and vascular anesthesia Schmidt, A. R., Collins, R. T., Adusumelli, Y., Ramamoorthy, C., Weng, Y., MacMillen, K. L., Navaratnam, M. 2021


    OBJECTIVE: This study compared the percent change in systolic blood pressure and the incidence of adverse cardiac events (ACEs; defined as cardiac arrest, cardiopulmonary resuscitation, arrhythmias, or ST-segment changes) during anesthesia induction in patients with Williams syndrome (WS) before and after implementation of a perioperative management strategy.DESIGN: Retrospective observational cohort study.SETTING: Single quaternary academic referral center.PARTICIPANTS: The authors reviewed the records of all children with WS at the authors' institution who underwent general anesthesia for cardiac catheterization, diagnostic imaging, or any type of surgery between November 2008 and August 2019. The authors identified 142 patients with WS, 48 of whom underwent 118 general anesthesia administrations. A historic group (HG) was compared with the intervention group (IG).INTERVENTIONS: Change in perioperative management (three-stage risk stratification: preoperative intravenous hydration, intravenous anesthesia induction, and early use of vasoactives).MEASUREMENTS AND MAIN RESULTS: The authors determined event rates within 60 minutes of anesthesia induction. Standardized mean difference (SMD) was calculated (SMD >0.2 suggests clinically meaningful difference). Sixty-seven general anesthesia encounters were recorded in the HG (mean age, 4.8 years; mean weight, 16.3 kg) and 51 in the IG (mean age, 6.0 years; mean weight, 18.2 kg). The change in systolic blood pressure was -17.5% (-30.0, -5.0) in the HG versus -9% (-18.0, 5.0) in the IG (p = 0.015; SMD = 0.419), and the incidence of ACEs was 6% in the HG and 2% in the IG (p = 0.542; SMD = 0.207).CONCLUSIONS: Preoperative risk stratification, preoperative intravenous hydration, intravenous induction, and early use of continuous vasoactives resulted in greater hemodynamic stability, with a 2% incidence of ACEs.

    View details for DOI 10.1053/j.jvca.2021.04.019

    View details for PubMedID 34049787

  • Rabbit training model for establishing an emergency front of neck airway in children. British journal of anaesthesia Both, C. P., Diem, B. n., Alonso, E. n., Kemper, M. n., Weiss, M. n., Schmidt, A. R., Deisenberg, M. n., Thomas, J. n. 2021


    A 'cannot intubate, cannot oxygenate' (CICO) situation is rare in paediatric anaesthesia, but can always occur in children under certain emergency situations. There is a paucity of literature on specific procedures for securing an emergency invasive airway in children younger than 6 yr. A modified emergency front of neck access (eFONA) technique using a rabbit cadaver model was developed to teach invasive airway protection in a CICO situation in children.After watching an instructional video of our eFONA technique (tracheotomy, intubation with Frova catheter over which a tracheal tube is inserted), 29 anaesthesiologists performed two separate attempts on rabbit cadavers. The primary outcome was the success rate and the performance time overall and in subgroups of trained and untrained participants.The overall success rate across 58 tracheotomies was 95% and the median performance time was 67 s (95% confidence interval [CI], 56-76). Performance time decreased from the first to the second attempt from 72 s (95% CI, 57-81) to 61 s (95% CI, 50-81). Performance time was 59 s (95% CI, 49-79) for untrained participants and 72 s (95% CI, 62-81) for trained participants. Clinical experience and age of the participants was not correlated with performance time, whereas the length of the tracheotomy incision showed a significant correlation (P=0.006).This eFONA training model for children facilitates rapid skill acquisition under realistic anatomical conditions to perform an emergency invasive airway in children younger than 2 yr.

    View details for DOI 10.1016/j.bja.2020.12.032

    View details for PubMedID 33526261