The purpose of considering pre-procedure oral intake is to reduce the risk of pulmonary aspiration of gastric contents. Fasting guidelines now practiced are expert opinion-based from the American Society of Anesthesiologists (ASA). These guidelines stipulate at least 2 hours of fasting for clear liquids, at least four hours for breast milk, and at least 6 hours for solids, cow's milk, and infant formula. These guidelines were originally intended to apply to only patients under going general anesthesia for elective procedures. Despite the fact that most procedural sedation and analgesia practice is moderate and dissociative sedation and not likely to produce loss of protective airway reflexes, the ASA believes the fasting time for sedation should be as long as that for general anesthesia.
However, emergency medicine practice is different. Scheduled and fasting are unusual in emergency medicine. Compliance with these guidelines would require holding patients in a department that already has limited space and staff. Extending emergency department stays for the purpose of fasting unduly prolongs pain and anxiety for the patient and family. Finally, there is no evidence of any benefit from adherence to ASA fasting guidelines for procedural sedation and analgesia. In fact hungry children have a greater rate of failed sedation.
To address these issues regarding fasting and sedation the following recommendations are based on the principle of doing what is best for the individual patient. An "all or none" approach will not account for the many variables that need to be considered when providing safe and effective sedation to the emergency patient. The goal will be to maximize the benefits and minimize the risks for each of these variables.
- Fasting: solids/non-human milk vs clear liquids. Adherence to solid/non-human milk fasting reduces risk of serious sequelae from aspiration.
- Aspiration pneumonitis in healthy patients from clear non-particulate fluids is generally a self-limited disease without serious sequelae.
- Aspiration pneumonitis of acidic particulate fluids tends to result in greater pulmonary damage.
- Patient characteristics: risk factors for aspiration. Adherence to fasting guidelines strongly recommended for patients at risk for aspiration.
- Gastroesophageal reflux or conditions predisposing to GE reflux/vomiting; esophageal disorders, gastric ulcer disease, gastritis, bowel obstruction, neuromuscular disorders, increased intracranial pressure, obesity or pregnancy.
- Potential difficult airway. Most aspirations associated with general anesthesia occur with airway manipulation (tracheal intubation/bag mask ventilation). Therefore adherence to fasting guidelines is strongly recommended for potential difficult airway patients that may require bag mask ventilation/tracheal intubation.
- Injuries/illnesses; the benefits of performing procedures for injuries/illnesses that require immediate/urgent attention to relieve pain/anxiety or to prevent complications from delayed management will commonly out weigh the risks of non-compliance with fasting guidelines.
- emergent cardioversion
- fracture with N/V compromise
- joint dislocation with N/V compromise
- incarcerated hernia
- lumbar puncture R/O meningitis
- arthrocentesis R/O septic arthritis
- eye irrigation
- abscess I & D
- uncomplicated fracture reduction
- sexual assault examination
- ear foreign body removal
- Depth of sedation; adherence to fasting guidelines strongly recommended for sedative agents that are used for deep sedation (propofol and etomidate) or inhibit airway protective reflexes (gag/cough).
- Monitoring; adherence to fasting guidelines strongly recommended for deep sedations performed without continuous CO2 monitoring.
- Physician; privileges to practice deep sedation will include yearly completion of mock code aspiration prevention scenario.
- Emergency Department patient volume and acuity.
- Patient/family satisfaction
- Green SM, Krauss B. Pulmonary Aspiration Risk during Emergency Department Procedural Sedation-an Examination of the Role of Fasting and Sedation Depth. Academic Emergency Medicine 2002;9:35-42
- Roback MG, Bajaj L, Wathen J, et al. Preprocedural Fasting and Adverse Events in Procedural Sedation and Analgeaia in a Pediatric Emergency Department: Are they Related? Ann Emerg Med 2004;44:454-459
- Agrawal D, Manzi SF, Gupta R, et al. Preprocedural Fasting State and Adverse Events in Children Undergoing Procedural Sedation and Analgesia in a Pediatric Emergency Department. Ann Emerg Med 2003;42:636-646
- Green SM. Fasting Is a Consideration-Not a Necessity-for Emergency Department Procedural Sedation and Analgesia. Ann Emerg Med 2003;42:647-650