This review discusses the evolution of preoperative fasting guidelines and examines the incidence of pulmonary aspiration of gastric contents and suggested treatments. Nine guidelines developed by professional societies and published in peer-reviewed journals since 1994 were identified. The recommendations on preoperative fasting for various categories have undergone only small adaptations in the following three decades in pediatric anesthesia. We found twelve published studies of the incidence of pulmonary aspiration, which ranges from 0.6 to 12 in 10,000 anesthetics in children. However, this variation reflects differences in the definition of aspiration as well as differences in study design. The main risk factors identified are emergency surgery, ASA physical status, and patient age. Several additional risk factors have been suggested, including non-compliance to fasting guidelines. The duration of clear fluid fasting is not associated with an increased risk of pulmonary aspiration which may be reflected in future guideline updates in pediatric anesthesia.

Adequate fluid management in the perioperative period in paediatric patients is essential for restoring and maintaining homeostasis and ensuring adequate tissue perfusion. A well-designed infusion regimen is crucial for preventing severe complications such as hyponatraemic encephalopathies. The composition of perioperative fluid solutions is now guided by an understanding of extracellular fluid physiology. Various crystalloid and colloidal products are available for use, but a comprehensive approach requires careful consideration of their drawbacks and limitations. Additionally, the unique characteristics of different patient groups must be taken into account. This review will provide the reader with physiological considerations for perioperative fluids and describe indications for perioperative intravenous fluid therapy in paediatric patients. The current evidence on perioperative fluid therapy is finally summarised in practical recommendations.

Big data in paediatric anaesthesia allows the evaluation of morbidity and mortality of anaesthesia in a large population, but also the identification of rare critical events and of their causes. This is a major step to focus education and design clinical guidelines. Moreover, they can help trying to determine normative data in a population with a wide range of ages and body weights. The example of blood pressure under anaesthesia will be detailed. Big data studies should encourage every department of anaesthesia to collect its own data and to benchmark its performance by comparison with published data. The data collection processes are also an opportunity to build collaborative research networks and help researchers to complete multicentric studies. Up to recently, big data studies were only performed in well developed countries. Fortunately, big data collections have started in some low and middle income countries and truly international studies are ongoing.

The field of pediatric neuroanesthesia has evolved with concurrent changes in pediatric neurosurgical practice. Ongoing pediatric neuroanesthesia investigations provide novel insights into developmental cerebrovascular physiology, neurosurgical technology, and clinical outcomes. Minimally invasive neurosurgical procedures appear to be associated with lower complication rates and length of stay. This review will discuss blood sparing techniques, regional anesthesia, and postoperative disposition. Collectively, these innovations appear to be safe in pediatric neurosurgical patients with potential benefits, but more data is needed for more definitive long-term outcomes.

Pediatric regional anesthesia has been in existence for over 125 years, but significant progress and widespread use has occurred in the last few decades, with the increasing availability of ultrasound guidance. Evidence supporting the safety of regional anesthesia when performed under general anesthesia has also allowed the field to flourish. Newer techniques allow for more precise nerve blockade and in general this has resulted in more peripheral blocks replacing central blocks, such as caudal epidurals and spinal anesthesia. Current controversial topics in the field include the method of obtaining loss of resistance when placing epidural catheters, the role of regional anesthesia in compartment syndrome and post-hypospadias repair complications, and utility of test doses.

Pediatric intensive care medicine is a rapidly evolving field of medicine, with recent publication of landmark papers specific for the pediatric population. Progress has been made in modes of mechanical ventilation, including noninvasive ventilation in pediatric ARDS and after extubation failure, with updated guidelines on ventilator liberation. Improved technology and advancements in hemodynamic support allow for better care of our patients with heart disease. Sepsis burden in children remains high and continued efforts are made to improve survival. A nutritional plan with a tailored approach, focusing on individualized needs, could offer benefits for our patients. Sedation practices and guidelines have been updated, focusing on minimizing delirium and facilitating early mobility. This manuscript highlights some of the most recent advances and updates.

Nowadays, widespread antenatal ultrasound screenings detect congenital anomalies earlier and more frequently. This has sparked research into foetal surgery, offering treatment options for various conditions. These surgeries aim to correct anomalies or halt disease progression until after birth. Minimally invasive procedures can be conducted under local anaesthesia (with/without maternal sedation), while open mid-gestational procedures necessitate general anaesthesia. Anaesthesia serves to prevent maternal and foetal pain, to provide immobilization, and to optimize surgical conditions by ensuring uterine relaxation. As early as 12 weeks after conception, the foetus may experience pain. Thus, in procedures involving innervated foetal tissue or requiring foetal immobilization, anaesthetic drugs can be administered directly to the foetus (intramuscular or intravenous) or indirectly (transplacental) to the mother. However, animal studies have indicated that exposure to prenatal anaesthesia might impact foetal brain development, translating these findings to the clinical setting remains difficult.

The elderly segment of the population is growing rapidly worldwide. Older patients comprise a disproportionate percentage of the surgical caseload. Physiological changes are inevitable with aging; some may impact a patient's response to anesthesia and surgery. Careful evaluation of an elderly patient preoperatively is vital to proper patient selection for ambulatory surgeries, particularly for complex and lengthy procedures. Cognitive issues, frailty, and geriatric syndromes make a patient vulnerable and sometimes unsuitable for certain ambulatory procedures. Preoperative planning and interventions may improve outcomes for the elderly patient undergoing ambulatory surgery.

Patient selection is important for ambulatory surgical practices. Proper patient selection for ambulatory practices will optimize resources and lead to increased patient and provider satisfaction. As the number and complexity of procedures in ambulatory surgical centers increase, it is important to ensure that patients are best cared for in facilities that can provide appropriate levels of care. This review addresses the multiple variables and resources that should be considered when selecting patients for anesthesia in ambulatory centers and offices.

Perioperative management of blood glucose is vital to the recovery and return to normal life for patients with diabetes undergoing ambulatory surgery. Important aspects of the preoperative assessment include the evaluation of the patient's usual level of control and self-management skills and the occurrence of hypoglycemia. There are disputes on the perioperative administration of diabetes medications, insulin, and certain other drugs. This article will provide information on current recommendations for ambulatory surgery and anesthesia for diabetic patients. It will address controversies and reemphasize important points of optimal care. New drugs and technologies for diabetes patients that may impact the perioperative period will be described.

Ambulatory surgery has been shown to be a management regimen associated with high quality of care and patient satisfaction. Recent research has suggested that some facets of emergency care could similarly be improved by earlier senior face-to-face consultation, a reduced time awaiting a surgical procedure and a 'fast track' recovery process. This review aims to provide information regarding the pathway of emergency ambulatory surgery and the typical changes required to optimise the process, whereby patients receive non-elective care in the most efficient way. While the concept may obviously not be suitable for all emergency care, the literature suggests that some procedures may benefit from optimisation of care, with a shortening of stay. To this end, within the United Kingdom, the National Health Service has developed a roll out of 'Same Day Emergency Care' using an established network of hospitals to deliver multi-disciplinary teamwork and further the concept of shorter stays in the hospital domain.

During the spring of 2020, as Coronavirus Disease 2019 (COVID-19) infections rapidly spread across the globe, all sectors of healthcare, everywhere, would change in ways that were unimaginable. Early on, the ambulatory surgery space, being no exception, would suffer deep and impactful reductions in patient volume and revenue. Though actual care stoppages were short-lived, decreased ambulatory surgical patient volumes continued for a myriad of reasons, though in some cases, ambulatory surgery centers (ASCs) provided surgical care in limited numbers to patients who were "offloaded" from inpatient lists. Released on March 24, 2020, herein, we address the key perioperative issues as they relate to COVID-19 and ambulatory surgery including the many complexities and challenges of a new and rapidly changing virus, the impact of viral infection and vaccine development on perioperative outcomes, key ambulatory surgical approaches to COVID-19-related patient and staff safety, and finally, managing issues related to both supply chain (personal protective equipment (PPE) and other necessary equipment) and facility staffing.

In comparison to large acute care centers, Ambulatory Surgery Centers (ASCs) provide patient-centered, fast, efficient, effective, high-value, high-quality, reliable, and safe care. For these reasons, ASCs are often preferred working venues for perioperative staff and desirable partners for surgeons, proceduralists, and anesthesiologists. Given today's many headwinds, including inflation, downward rate pressures, increasing regulation, and near constant supply chain issues, not to mention increasing patient and procedural complexity, exemplary clinical and operational management is of paramount importance and requires frequent measurement and benchmarking. Benchmarking is critical to performance assessment and is vital for assessing existing processes and new pathways and protocols, and remains the best way to identify areas for improvement. This chapter provides the reader with an overview of key ASC-related performance indicators, what they mean, and how best to measure and compare them to local, regional, and national benchmarks.

Obesity and obstructive sleep apnea are considered independent risk factors that can adversely affect perioperative outcomes. A combination of these two conditions in the ambulatory surgery patient can pose significant challenges for the anesthesiologist. Nevertheless, these patients should not routinely be denied access to ambulatory surgery. Instead, patients should be appropriately optimized. Anesthesiologists and surgeons must work together to implement fast-track anesthetic and surgical techniques that will ensure successful ambulatory outcomes.

The number of patients with congenital heart disease (CHD) undergoing ambulatory surgery is increasing. Deciding whether a CHD patient is suitable for an ambulatory procedure is still challenging. Several factors must be considered, including the type of planned procedure, the complexity of the underlying pathology, the American Society of Anesthesiologists' Physical Status classification of the patient, and other patient-specific factors, including comorbidity, chronic complications of CHD, medication, coagulation disorders, and issues related to the presence of a pacemaker (PM) or cardioverter-defibrillator. Numerous studies reported higher perioperative mortality and morbidity rates in surgical patients with CHD than non-CHD patients. However, most of these studies were conducted in a cohort of hospitalized patients and may not reflect the ambulatory setting. The current review aims to provide the anesthesiologist with an overview and practical recommendations on selecting and managing a CHD patient scheduled for an ambulatory procedure.

In the United States, ambulatory surgeries account for up to 87% of all surgical procedures. (1) It was estimated that 19.2 million ambulatory surgeries were performed in 2018 (https://www.hcup-us.ahrq.gov/reports/statbriefs/sb287-Ambulatory-Surgery-Overview-2019.pdf). Cataract procedures and musculoskeletal surgeries are the most common surgical interventions performed in ambulatory centers. However, more complex surgical interventions, such as sleeve gastrectomies, oncological, and spine surgeries, and even arthroplasties are routinely performed as day cases or in a model of an ambulatory extended recovery. (2-5) The ambulatory surgery centers industry has grown since 2017 by 1.1% per year and reached a market size of $31.2 billion. According to the Ambulatory Surgery Center Association, there is a potential to save $57.6 billion in Medicare costs over the next decade (https://www.ibisworld.com/industry-statistics/market-size/ambulatory-surgery-centers-united-states/). These data suggest an expected rise in the volume of ambulatory (same day) or extended ambulatory (23 h) surgeries in coming years. Similar increases are also observed in other countries. For example, 75% of elective surgeries are performed as same-day surgery in the United Kingdom. (6) To reduce costs and improve the quality of care after those more complex procedures, ambulatory surgery centers have started implementing patient-centered, high-quality, value-based practices. To achieve those goals, Enhanced Recovery After Surgery (ERAS) protocols have been implemented to reduce the length of stay, decrease costs, increase patients' satisfaction, and transform clinical practices. The ERAS fundamentals for ambulatory surgery are based on five pillars, including (1) preoperative patient counseling, education, and optimization; (2) multimodal and opioid-sparing analgesia; (3) nausea and vomiting, wound infection, and venous thromboembolism prophylaxis; (4) maintenance of euvolemia; and (5) encouragement of early mobility. Those pillars rely on interdisciplinary teamwork led by anesthesiologists, surgery-specific workgroups, and safety culture. (2) Research shows that a team of ambulatory anesthesiologists is crucial in improving postoperative nausea and vomiting (PONV) and pain control. (7) This review will summarize the current evidence on the elements and clinical importance of implementing ERAS protocol for ambulatory surgery.

Balanced anesthesia relies on the simultaneous administration of different drugs to attain an anesthetic state. The classic triad of anesthesia is a combination of a hypnotic, an analgesic, and a neuromuscular blocker. It is predominantly the analgesic pillar of this triad that became more and more supported by adjuvant therapy. The aim of this approach is to evolve into an opioid-sparing technique to cope with undesirable side effects of the opioids and is fueled by the opioid epidemic. The optimal strategy for balanced general anesthesia in ambulatory surgery must aim for a transition to a multimodal analgesic regimen dealing with acute postoperative pain and ideally reduce the most common adverse effects patients are faced with at home; sore throat, delayed awakening, memory disturbances, headache, nausea and vomiting, and negative behavioral changes. Over the years, this continuum of "multimodal general anesthesia" adopted many drugs with different modes of action. This review focuses on the most recent evidence on the different adjuvants that entered clinical practice and gives an overview of the different mechanisms of action, the potential as opioid-sparing or hypnotic-sparing drugs, and the applicability specifically in ambulatory surgery.

Total joint arthroplasty is one of the most commonly performed surgical procedures in the United States, and projected numbers are expected to double in the next ten years. From 2018 to 2020, total hip and knee arthroplasty were removed from the United States' Center for Medicare and Medicaid Services "inpatient-only" list, accelerating this migration to the ambulatory setting. Appropriate patient selection, including age, body mass index, comorbidities, and adequate social support, is critical for successful ambulatory total joint arthroplasty. General anesthesia and neuraxial anesthesia are both safe and effective anesthetic choices, and recent studies in this population have found no difference in outcomes. Multimodal analgesia, including acetaminophen, nonsteroidal anti-inflammatory drugs, local infiltration analgesia, and peripheral nerve blocks, is the foundation for adequate pain control. Common reasons for "failure to launch" include postoperative urinary retention, postoperative nausea and vomiting, inadequate analgesia, and hypotension.

Regional anaesthesia (RA) has an important and ever-expanding role in ambulatory surgery. Specific practices vary depending on the preferences and resources of the anaesthesia team and hospital setting. It is used for various purposes, including as primary anaesthetic technique for surgery but also as postoperative analgesic modality. The limited duration of action of currently available local anaesthetics limits their application in postoperative pain control and enhanced recovery. The search for the holy grail of regional anaesthetics continues. Current evidence suggests that a peripheral nerve block performed with long-acting local anaesthetics in combination with intravenous or perineural dexamethasone gives the longest and most optimal sensory block. In this review, we outline some possible blocks for ambulatory surgery and additives to perform RA. Moreover, we give an update on local anaesthesia drugs and adjuvants, paediatric RA in ambulatory care and discuss the impact of RA by COVID-19.