Gastric Emptying

* The goal of this observational study is to learn whether the stomach takes longer to empty in patients on the intensive care unit who are receiving ECMO (a machine that temporarily takes over the role of the lungs and heart) compared to patients receiving support through a breathing machine (mechanical ventilation) only. It will also find the best way to measure stomach emptying at the bedside. * The main questions it aims to answer are: * What is the prevalence of slow stomach emptying and other stomach or bowel problems in patients receiving ECMO, compared to patients receiving mechanical ventilation but not receiving ECMO? (Stage A) * What is the best bedside method to measure stomach emptying in patients receiving ECMO? (Stage B) * Stage A of the study will involve measuring stomach emptying in study participants within four days of ICU admission, using two bedside methods: * 'Residual volumes' (removing liquid nutrition left in the stomach with a syringe, after this has been given through the participant's usual feeding tube) * A stomach ultrasound scan The researchers will check for differences between patients receiving ECMO versus no ECMO, and how this relates to the nutrition patients receive and how well or unwell they become in ICU. * In a smaller subgroup of patients receiving ECMO and participating in Stage B of the study, the researchers will also use scintigraphy. This is a standard research scan that tracks how the stomach empties by mixing a small, safe amount of radioactivity in the participant's usual liquid nutrition. The researchers will compare stomach emptying results from 'residual volumes' and stomach ultrasound with scintigraphy.

The objective of this clinical trial is to evaluate the effect of a nutritional formula composed of carbohydrates and proteins on gastric emptying in elderly individuals aged between 60 and 90 years. The main questions this study aims to answer are: * Does the nutritional formula composed of carbohydrates and proteins delay gastric emptying when compared to a formula composed only of carbohydrates? * Does the formula composed of carbohydrates and proteins cause gastrointestinal symptoms in the study population? The researchers will compare both formulas (carbohydrates and proteins vs. carbohydrates only) to answer the main question. Participants will be required to: * Attend the Nuclear Medicine Department after an 8-hour fast, on two separate days with a minimum interval of seven days for scintigraphy procedures. * Consume the offered formula in a randomized and blinded manner. * Report any gastrointestinal symptoms and complete visual analog scales for sensations such as hunger, satiety, and desire to eat.

According to the American Society of Anesthesiologists (ASA) fasting guideline for patients undergoing elective surgery, the 2-hour fasting period is suggested for clear oral fluid (including water, pulp-free juice and tea or coffee without milk). This guideline does not give any suggestions for proper volume of clear oral fluid intake. This study is a prospective randomized control trials in children aged 13 through 17 years who are scheduled for an elective upper GI endoscopy procedure in the Gastroenteral Procedure Unit (GPU) at Boston Children's Hospital. The participants will be randomly assigned into one of four groups: Group 1 will consume 3 ml/kg of clear fluid by mouth at 2-hour period before surgical scheduled time, Group 2 will consume 5 ml/kg, Group 3 will consume 7 ml/kg, and Group 4 will consume 10 ml/kg. The investigators plan to recruit 72 patients in each group and 288 patients for the whole study. Research team will collect patient's demographic data, vital signs, information about their EGD procedure. Then actual volume of the stomach content and acidity will be measured from the content that is suctioned from patient's stomach during upper GI endoscopy procedure. The investigators believe that the information from this study will help establish a comprehensive NPO guideline.

Ultrasound imaging will be used to evaluate time for gastric emptying in healthy, fasting newborns, and infants following feeding of clear liquids and/or milk (including breast or formula).

'Sip Til send' is a liberal drinking policy that replaces fasting before a caesarean delivery, meaning that women waiting in hospital can freely drink sips of water until they are called from the ward for their delivery. Studies has shown that 'Sip Til send' is safe and it improves the experience around surgery. Separate from this, drinking carbohydrate-rich drinks at specified time intervals before surgery is also recommended by international guidelines as part of a package of care aimed at enhancing recovery from surgery, and studies demonstrate that carbohydrate drinks significantly lower hunger sensation before caesarean delivery. The aim of this study is to combine these two interventions and compare the effects of sipping water against sipping carbohydrate drinks whilst waiting for a caesarean delivery and look at the stomach contents before delivery to ensure it is a safe practice and look at how women rate the quality of their recovery to see which practice is preferred. We will recruit women due to have an elective caesarean delivery whilst awake with a spinal anaesthetic at the Rotunda Hospital and only include those who are fully fasted on their arrival and would be candidates for the current 'Sip Til Send' policy. They will then be assigned to one of two groups, the "water" group who will be encouraged to sip water whilst waiting for surgery, and the "carbohydrate" group who will be encouraged to sip a standardised carbohydrate-rich drink instead. Using a bedside ultrasound machine, we will image the stomach and estimate the volume of liquid contents on two occasions; first, following recruitment to the study when fully fasted and before starting 'Sip Til Send', and second is immediately prior to surgery. Fluid intake will be closely monitored, and all participants will be asked to complete a short questionnaire the day after their delivery that asks them to rate aspects of their recovery. Participants and their newborns will not undergo any additional invasive testing for the study. Participants and their newborns will not undergo any additional invasive testing for the study, but consent will be sought to test women's urine for ketones (collected from the catheter bag during surgery). Medical notes will also be looked at after discharge to identify adverse outcomes such as nausea or vomiting during surgery and low blood sugar in the newborn. The study should run for approximately 3 to 6 months.

To determine the half time of the emptying of the stomach of women in early labor with and without epidural pain relief when drinking either water or a carbohydrate-based sports drink.

Gastric content is a key risk factor for aspiration during anesthesia. Although standard fasting times are recommended, various factors-including GLP-1 receptor agonists,-can delay gastric emptying. Gastric ultrasound enables real-time, non-invasive assessment of gastric volume and can help tailor perioperative management. The aim of this study explores the effects of different meal types and physical activity on gastric emptying in healthy individuals.