NPO for the Love…Let them drink!

By Benjamin F. Jackson, MD

An update on pre-procedural fasting and pediatric procedural sedation

Among the more commonly recurring discussions and controversies in the realm of pediatric procedural sedation (PPS) surrounds the provision of sedation and its relationship to timing of a patient’s most recent oral intake. While PPS care remains one of the strongest examples of multidisciplinary overlap and collaboration, the Nil per os (NPO) issue has been shown to return providers to their respective specialty camps and preferences for PPS practice, which may diverge from those of others with distinct backgrounds and clinical experiences. An updated look at the literature supporting pre-procedural fasting and PPS timing is certainly warranted with an aim to promote PPS quality without compromising patient safety.

With the intent of diminishing the risk of perioperative/peri-procedural aspiration of gastric contents into the larynx and lower respiratory tract as well as the potential for aspiration pneumonitis and concomitant morbidity, the American Society of Anesthesiologists (ASA) has published a fasting guideline intended for healthy patients of all ages receiving “anesthesia care”, which the ASA has defined as general anesthesia, regional anesthesia, or procedural sedation and analgesia, to facilitate elective procedures.¹ The ASA acknowledges that these recommended times do not ensure complete gastric emptying and are modifiable for patients with co-morbidities (e.g., obesity, pregnancy, reflux, diabetes mellitus, bowel obstruction) or for those in need of emergency procedural care. Nevertheless, the ASA guideline is the most broadly applied fasting guideline in anesthesia and procedural sedation settings, is routinely included in institutional sedation policies, and has been adopted by the American Academy of Pediatrics (AAP) in its procedural sedation practice guideline.²

• Pulmonary aspiration of a clinically apparent degree is a rare occurrence in PPS.
  In 2016, the Pediatric Sedation Research Consortium (PSRC) published a report on the relationship of major adverse events including aspiration to NPO status for PPS encounters with natural airway strategies outside the operating room.³ From this large data with ~140,000 PPS encounters with NPO status known for ~108,000 patients, aspiration was reported in only 10 patients total, all of whom > 6 hours of fasting from solid intake; 8 of the 10 cases were fully compliant with fasting guidelines and 2 were not NPO. The incidence of aspiration in PPS is ~0.7 cases per 10,000 sedations, approximately one-half to one-third the rate reported for general anesthesia in children.
• PPS for unscheduled, time-sensitive urgent/emergent procedures commonly necessitates fasting guideline nonadherence without increased risk of resultant associated severe adverse event.
  In 2018, Bhatt et al reported prospective outcomes from 6183 ED PPS cases and found no association between fasting duration and any type of sedation-related adverse event.⁴ Also in 2018, Chumpitazi et al published outcomes of 2188 ED PPS encounters and found that patients with shorter fasting intervals had no difference in rates of emesis yet had had significantly decreased ED length of stay.⁵ No aspiration occurred in either study.
• Compliance with fasting guideline times does not ensure empty stomach—especially in patients with painful conditions who receive opioid analgesia.
  Two recent ED studies from Leviter et al and Moake et al utilized point-of-care ultrasound to assess gastric content and found that patients awaiting sedated procedures with times of 6+ hours since last reported oral intake had solid content present.^6-7 No patient in either study experienced PPS-related adverse respiratory event irrespective of the reported fasting interval or gastric content. Many had received opioid analgesia prior to sedation. It is well established that both pain itself and opioid analgesia reduce gastric emptying and gastrointestinal motility. It should be assumed that a patient warranting PPS in this clinical context has a full stomach.
• Consider ketamine for emergent unscheduled PPS—especially if complete patient immobility is not required.
  Ketamine induces a trancelike cataleptic state of dissociation, reliably delivering “potent analgesia, sedation, and amnesia while maintaining cardiovascular stability and preserving spontaneous respirations and protective airway reflexes”.⁸ Caution with ketamine use is particularly advised for posterior oropharyngeal procedures with the potential to induce gagging and coughing and then either emesis and/or laryngospasm. Ketamine dissociative sedation has been recommended for urgent/emergent PPS in the American College of Emergency Physician’s Multidisciplinary Guideline for Unscheduled Procedural Sedation and by the International Committee for the Advancement of Procedural Sedation’s Multidisciplinary Consensus Statement on Fasting before Procedural Sedation.^9-10
• PPS risk assessment should focus on patient age, anatomy, co-morbid conditions, and procedural specifics as far more important than preprocedural fasting duration.
  Age < 12 months, airway abnormalities, ASA class III or IV, obesity (BMI > 85%), obstructive sleep apnea, gastroesophageal reflux and other esophageal disorders, hyperemesis, bowel obstruction, bronchoscopic and endoscopic procedures, and a history of sedation complication are among the most notable contributors to risk of sedation-related adverse event including aspiration, cardiac arrest, and unanticipated hospitalization.^3,9-10
• Prolonged fasting intervals may have deleterious effect on PPS quality. Permitting glucose-rich clear liquids up to 1 hour prior to PPS for appropriately risk-stratified patients prior reinforces the commitment to patient-/family-centered care without introducing additional adverse event risk.
  For young children in particular, resultant hunger and thirst from lengthy preprocedural fasts may lead to hypoglycemia, dehydration, discomfort, agitation, and behavioral distress, posing difficulties for parents and introducing challenges into the sedation and recovery event. To mitigate these detrimental effects without compromising safety, leaders of the Great Britain & Ireland, French, and European Pediatric Anesthetist societies released a joint consensus statement in 2018 calling for shortened preprocedural fluid intake interval: “Clear fluids for elective general anesthesia and sedation can be reduced to 1 hour unless clinically contraindicated … includ[ing] gastro-esophageal reflux (either on treatment or under investigation), renal failure, severe cerebral palsy, some enteropathies, esophageal strictures, achalasia, diabetes mellitus with gastroparesis, and/or surgical contraindications.”¹¹

The Society for Pediatric Sedation champions well-organized, highly motivated PPS systems, and in this context with vigilant patient selection and screening, PPS has proven safe and effective. Enhancement of quality of PPS experiences for patients (and thereby families) should include incorporation of more liberal permissibility of preprocedural clear liquid intake. Furthermore, with application of sound risk stratification approaches, available evidence suggests it is reasonable to provide sedation to patients who are incompletely fasted according to conventionally utilized guidelines. The Society for Pediatric Sedation extols the virtues of collaboration and mutual respect among PPS providers from a breadth of disciplines who embrace a commitment to pediatric sedation excellence. It is incumbent upon each sedation provider to derive from the available evidence and his/her clinical experience a plan that optimizes quality and safety for every respective patient.

References

1. American Society of Anesthesiologists Task Force. Practice guidelines for preoperative fasting and the use of pharmacologic agents to reduce the risk of pulmonary aspiration: application to healthy patients undergoing elective procedures: an updated report. Anesthesiology. 2017; 3: 376-393.
2. Cote CJ, Wilson S. American Academy of Pediatrics and American Academy of Pediatric Dentistry. Guidelines for monitoring and management of pediatric patients before, during, and after sedation for diagnostic and therapeutic procedures. Pediatrics. 2019; 143 (6): e20191000.
3. Beach ML, Cohen DM, Gallagher SM, Cravero JP. Major adverse events and relationship to nil per os status in pediatric sedation/anesthesia outside the operating room: a report of the pediatric sedation research consortium. Anesthesiology. 2016; 124 (1): 80-88.
4. Bhatt M, Johnson DW, Taljaard M, et al. Association of preprocedural fasting with outcomes of emergency department sedation in children. JAMA Pediatr. 2018; 172 (7): 678-685.
5. Chumpitazi CE, Camp EA, Bhamidipati DR, et al. Shortened preprocedural fasting in the pediatric emergency department. Am J Emerg Med. 2018; 36 (9): 1577-1580.
6. Leviter J, Steele DW, Constantine E, et al. “Full stomach” despite the wait: point-of-care gastric ultrasound at the time of procedural sedation in the pediatric emergency department. Acad Emerg Med. 2019; 26: 752-760.
7. Moake MM, Presley BC, Hill JG, et al. Point-of-care ultrasound to assess gastric content in pediatric emergency department procedural sedation patients. Pediatr Emerg Care. 2020; online ahead of print. PMID: 32769837 DOI: 1097/PEC.0000000000002198
8. Green SM, Roback MG, Kennedy RM, Krauss BC. Clinical practice guideline for emergency department ketamine dissociative sedation: 2011 update. Ann Emerg Med. 2011; 57 (5): 449-461.
9. Green SM, Roback MG, Krauss BS, et al. Unscheduled procedural sedation: a multidisciplinary consensus practice guideline. Ann Emerg Med. 2019; 73 (5): e51-e65.
10. Green SM, Leroy PL, Roback MG, et al. An international multidisciplinary consensus statement on fasting before procedural sedation in adults and children. Anaesthesia. 2020; 75 (3): 374-385.
11. Thomas M, Morrison C, Newton R, Schindler E. Consensus statement on clear fluids for elective pediatric general anesthesia. Paediatr Anaesth. 2018; 28 (5): 411-414.