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SGEM#165: I Wanna Be Sedated – But Do I Need To Be NPO?

SGEM#165: I Wanna Be Sedated – But Do I Need To Be NPO?

Podcast Link: SGEM165

Date: November 22nd, 2016

Reference: Beach et al. Major Adverse Events and Relationship of Nil per Os Status in Pediatric Sedation/Anesthesia Outside the Operating Room. Anesthesiology January 2016

Guest Skeptic: Dr. Bob Edmonds has just completed his residence in Emergency Medicine from the University of Missouri in Kansas City. He is now an emergency department staff physician in the US Air Force at Langley Air Force Base.

Dr. Edmonds’ Disclaimer: The views and opinions of this podcast and blog are not the official position of the United States Air Force, the US government, or Langley Air Force Base.

img_3429Thanksgiving: This episode is being published on American Thanksgiving 2016 weekend. Happy Thanksgiving to all the SGEMers from the USA. We hope everyone has a wonderful holiday spent with family and friends.

Case: A 5-year-old girl was bit in the face by a neighbor’s dog. She has a complex lower lip laceration that extends beyond the vermillion border with a flap deformity. You believe it will require repair by an oral and maxillofacial surgeon in your emergency department and that the patient will require procedural sedation. The patient had been eating a turkey sandwich one hour ago and you consider how long to leave her NPO prior to the sedation.

Background: Procedural sedation is a somewhat common practice in the emergency department for a number of pediatric cases such as laceration repair, incision and drainage, closed reduction of fractures, and radiographic studies such as CT scans.

The American Society of Anesthesiologists 2011 Practice Guidelines recommends waiting two hours  for clear liquids, six hours for light meals and eight hours may be needed in other cases before elective procedures requiring general anesthesia, regional anesthesia, or sedation/analgesia. They recognize that these guidelines may not apply to emergency care.

The ACEP Clinical Policy on procedural sedation and analgesia in the emergency department from 2013 gives a Level B recommendation of not delaying procedural sedation in adults or pediatric emergency department patients based on fasting time.

  • Pre-procedural fasting for any duration has not demonstrated a reduction in the risk of emesis or aspiration when administering procedural sedation and analgesia. 

Clinical Question: Do we need to delay procedural sedation of pediatric emergency department patients based on their NPO status?


Reference: Beach et al. Major Adverse Events and Relationship of Nil per Os Status in Pediatric Sedation/Anesthesia Outside the Operating Room. Anesthesiology January 2016

  • Population: All pediatric patients undergoing procedural sedation at one of the 42 Pediatric Sedation Research Consortium (PSRC) sites from September 2, 2007 to November 9, 2011. Procedural sedation/anesthesia was defined as “any pharmacologic intervention made to facilitate an invasive procedure or test in a pediatric-age patient outside of the operating room environment.”
  • Intervention: NPO to solids for at least eight hours, non clear fluids for at least six hours, and clear fluids for at least two hours
  • Comparison: Patients who failed to meet the above NPO criteria
  • Outcome: Two primary outcomes
    • Rate of aspiration (Aspiration episode was defined as an event where emesis was noted or food material was found in the oral/pharyngeal cavity and associated with any or the following: new cough, wheeze, increase in respiratory effort, change in chest radiograph indicative of aspiration, or new need for oxygen therapy after recovery from sedation).
    • Occurrence of a major adverse event (defined as aspiration, death, cardiac arrest, or unplanned admission to a hospital).

Authors’ Conclusions: The analysis suggests that aspiration is uncommon. NPO status for liquids and solids is not an independent predictor of major complications or aspiration in this sedation/anesthesia data set.

checklistQuality Checklist for Observational Study:

  1. Did the study address a clearly focused issue? Yes. Adverse outcomes related to NPO status for procedural sedation outside the operating room.
  2. Did the authors use an appropriate method to answer their question? Yes. They wanted to evaluate if any links existed between NPO status and aspiration, pulmonary adverse events and major adverse events. A prospective observational study can be used to identify associations.
  3. Was the cohort recruited in an acceptable way? Yes. They had consecutive enrollment at multiple centers.
  4. Was the exposure accurately measured to minimize bias? Yes. The primary analysis was only using data where NPO status was known. If NPO status was unknown for a variable like solids or liquids it was marked as unknown. A secondary analysis was used with a multiple imputation model to try to make up for the group of patients where NPO status was not known.
  5. Was the outcome accurately measured to minimize bias? Yes/No
  6. Have the authors identified all-important confounding factors? No.
  7. Was the follow up of subjects complete enough? Yes.
  8. How precise are the results/is the estimate of risk? Not Great. With only a few events the 95% confidence intervals are wide.
  9. Do you believe the results? Yes.
  10. Can the results be applied to the local population? Unsure.
  11. Do the results of this study fit with other available evidence? Yes.

Key Results: They had 139,142 procedural sedation/anesthesia encounters identified in the data set. NPO status was known for 107,947 patients, with 25,401 (24%) were not NPO. They observed 75 major complications (62 unplanned admission, ten aspiration, three cardiac arrest and no death).


Primary outcome: No statistical association between NPO status and major complications or aspiration.


Screen Shot 2015-04-25 at 3.11.12 PM

  1. Asking the Right Question: They did answer their question about if any links existed between NPO status and aspiration, pulmonary adverse events, and major adverse events. A prospective observational study can be used to identify associations. However, what we want to know is cause and effect of NPO status of pediatric emergency department patients requiring procedural sedation. It would take a randomized control trial to investigate causation. The trial would need to be very large given the low event rate. And finally, it would need to take place in the emergency department with pediatric emergency patients.
  2. Outcome Bias: Aspiration had a clear definition that was easily measured. However, the definition of major adverse events or complications was recognized as being arbitrary by the authors. They specifically point out that unanticipated intubation or an emergency anesthesia consult may result in some provider bias.
  3. Confounders: While they were able to collect data on the type of practitioner, ASA status, type of procedure and other things they were not able differentiate the type of solid food eaten and if the care had been transferred to an anesthesiologist in the operating room for intubation.
  4. Precision of the Results: Because there were only a few events, the 95% confidence intervals around the point estimate were wide.
  5. Applying the Results to your Local Population: It all depends. The authors note a limitation that “the providers of the sedation in this particular study were working in high-performance sedation teams“. If your hospital does not have a high-performance sedation team that provides service to your emergency department the results may not apply to your site. In addition, these were mainly elective procedures and only a minority were classified as emergencies and performed by emergency physicians.

Comment on authors’ conclusion compared to SGEM Conclusion: We generally agree with the authors’ conclusions.


SGEM Bottom Line: It is reasonable not to delay procedural sedation in a pediatric emergency department patients based on their NPO status.


Case Resolution: You have an informed discussion with the family regarding their daughter’s injury and the risks of sedation. You make a joint decision to proceed with the sedation and have the oral and maxillofacial surgeon perform the laceration repair. The child undergoes the sedation without complications and upon awakening, asks to go home.

Dr. Robert Edmonds

Dr. Robert Edmonds

Clinical Application: It will always be difficult to risk stratify rare conditions, but this paper offers support to those in favor of more rapid initiation of procedural sedation, regardless of NPO status. I  am a little more tacit with adoption of this paper into practice. I support the findings of the paper, but the study was limited for some of the reasons we discussed. The paper does support ACEP’s clinical guidelines and adds to the available evidence to support procedural sedation independent of NPO status. However, as always, you must use your judgement.

What do I tell my patient? Complications from procedural sedation are uncommon but something we constantly prepare for. A common thought in medicine is that there is increased risk of one of these complications if sedation is started after recent food or drink ingestion. A study of a large group of children recently demonstrated no increased risk based on food or drink ingestion. The American College of Emergency Physician says emergency doctors should not delay procedures based on fasting time. With your permission, we’d like to begin the sedation now to repair your daughter’s injury.

Keener Contest: There was no keener question last episode because it was an SGEM Xtra. Listen to the podcast for this weeks’ question. If you know the answer then send an email to TheSGEM@gmail.com with “keener” in the subject line. The first correct answer will receive a cool skeptical prize.

FOAMed Resources:

  • LITFL – Peri-procedural Fasting
  • PEM Blog – NPO for Sedation
  • EMCrit – ACEP Procedural Sedation Update for 2013

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.


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