Clinical Editor's Corner: Kern

“Let the Patient Eat.” Isn’t It Time to Change the NPO Rule for the Cath Lab?

Morton J. Kern, MD, with contributions from Drs. James Blankenship, Hershey, Pennsylvania; John Bittl, Ocala, Florida; Sam Butman, Cottonwood, Arizona; Kirk Garrett, Newark, Delaware; Alan Jeremias, Stony Brook, New York; Jeffrey Moses, New York City, New York; Pinka Bipin Shaw, Boston, Massachusetts; Sunil Rao, Durham, North Carolina; Arnold Seto, Long Beach, California.

Morton J. Kern, MD, with contributions from Drs. James Blankenship, Hershey, Pennsylvania; John Bittl, Ocala, Florida; Sam Butman, Cottonwood, Arizona; Kirk Garrett, Newark, Delaware; Alan Jeremias, Stony Brook, New York; Jeffrey Moses, New York City, New York; Pinka Bipin Shaw, Boston, Massachusetts; Sunil Rao, Durham, North Carolina; Arnold Seto, Long Beach, California.

In 2010 in CLD (http://www.cathlabdigest.com/articles/Should-NPO-Be-Rule-Cath-Reexamining-Pre-Procedure-Routines), we talked about the need to change the NPO routine. To paraphrase Dr. John Bittl, “… it’s time to eliminate the NPO order.” Dr. Kirk Garrett said, “No, it’s below the standard (not to be NPO).” I thought it would be worthwhile to follow up on this issue, prompted by Nancy Reyes, BSN, RN, CV-BC, a nurse in the Heart Center Pre/Post Procedure Care Unit at WakeMed Health and Hospitals in Raleigh, North Carolina. As chair of her unit Policy/Procedure Committee, she asked our lab where we are on the issue. What is the rationale for continuing the NPO order? 

Like Nurse Reyes, we, too, have our challenges accepting a rigid NPO status for daily cath lab operation. Recently, in our lab, Dr. Arnold Seto had a patient set up for elective cath. The patient adhered to the NPO after midnight order, but after checking in to the same-day procedure area, decided to eat breakfast. Should we cancel the case or proceed without any sedation at all (since it’s a radial case)? This situation threw a wrench in our schedule for sure.

To review why the NPO order has been in our workflow for so many years, some seniors (me included) can recall cath lab history, a time when catheterization was considered like a surgical procedure and the same rules for surgical preparations were adopted. In contrast to anesthesia, which often had side effects of nausea and vomiting during recovery, the catheterization procedure used radiographic contrast media (e.g. Renografin, a high-osmolar ionic), which also was associated with nausea/vomiting and risk of aspiration. Over the decades, improvements in method and the use of low-osmolar contrast media have nearly eliminated vomiting as a consequence of cath. 

Why we should drop the NPO now

There are some significant downsides to the NPO for cardiac cath in that limiting of water intake is associated with dehydration and increases chances of renal failure.1,2 I’ve reproduced Dr. John Bittl’s comment from 2010:

“It’s time to eliminate the NPO order before invasive and interventional procedures, because 1) there is no hydration protocol that maintains euvolemia better than the homeostatic mechanisms of the body; 2) there is no compelling evidence that fasting makes conscious sedation safer; and 3) there is only about a 0.1% risk of needing emergency surgery for PCI [percutaneous coronary intervention]. In our program, for the past 13 (now 19) years, we have not required patients to fast. We do not decrease insulin doses. We have avoided intravascular volume depletion, hyperglycemia (which may contribute to acute kidney injury with contrast), and osmotic diuresis. We have decreased the number of hungry, disgruntled patients who complain to nurses. Patient and nurse satisfaction is therefore very high. Eliminating the NPO order is a radical idea, but it is something that every interventional program should consider.”

Why we should keep the NPO

Dr. Kirk Garratt, Christiana Hospital System, Newark, Delaware, summed it up: “… one aspiration event and you’re toast! In addition, you’re in violation of a ‘thousand’ guideline statements. In NYC [and probably Delaware — MK], for better or worse, this [fear] will keep patients fasting.” 

A brief poll of several cath lab directors sheds light on the current practice of the NPO rule.

Arnold Seto, Section Chief, Cardiology, VA Long Beach, California: Our cath lab permits oral fluid intake without restriction (including patients’ medications). We still do not recommend eating solids before the procedure. Our written instructions for outpatients are to be NPO after midnight, except for sips of water with morning medications. For our inpatients, our hospital moderate sedation policies nominally require 6 hours (at the University Hospital) or 8 hours (at the VA Hospital) of fasting without solid food, with clear liquids being allowed up to 2 hours before the procedure (both UC-Irvine and VA). I am certainly in the camp that believes that these NPO rules are based on surgical anesthesia and should have little bearing on the modest doses of medications we use in the cath lab, but we are bound by hospital policies. Many facilities, including VAs, regularly will stretch these rules to accommodate our patients, possibly by using anxiolysis only without narcotics, or pain medications only. The use of radial access requires very little sedation, in my opinion.

Sunil V. Rao, Duke University Medical Center, Durham, North Carolina: My opinion, for what it’s worth, is that NPO for cath/PCI is not necessary. I would never cancel a case solely because a patient ate. Nothing formal at our institution, but it is a topic of active discussion currently.

Pinak Bipin Shah, Brigham and Women’s Hospital (BWH), Boston, Massachusetts: The NPO policy at BWH is set by anesthesia, who oversees IVCS [intravenous conscious sedation] policies as well. NPO is 6 hours here. If we know a case is going to be very late in the day, we have given patients breakfast and then plan on their case later. We have definitely cut NPO time shorter (or bypassed altogether) for less complex procedures that can be done quickly and where sedation can be avoided. I think almost all of our colleagues here would prefer it [no NPO order] because of the issues surrounding potential nausea, vomiting, and aspiration. 

Jeffery Moses, Columbia University, New York City: [For NPO, it’s the] same at Columbia [that] anesthesia sets the rules. The issue is liability if things go south. Remember the Paul Newman movie “The Verdict”!

John Bittl, Ocala, Florida: After consulting with our cardiovascular (CV) anesthesiologists and reviewing the literature on aspiration during “conscious” or mild to moderate sedation, we eliminated the NPO order almost 20 years ago. Eliminating the NPO order has improved patient and nursing satisfaction, and at the risk of invoking hubris, seems to have eliminated contrast nephropathy. We summarized our experience in Catheterization and Cardiovascular Interventions in 2014.3 Like Jeff Moses, we liked “The Verdict” when we saw it in 1982, but the movie focused on an obstetrical complication >32 years ago and might be irrelevant as a source of evidence for interventional cardiology practice in 2016.

James Blankenship, Hershey, Pennsylvania: Our policy is no solids for 6 hours and no liquids for 2 hours (except no coffee for 6 hours since interferes with adenosine if we do FFR [fractional flow reserve] testing), but like Dr. Rao, we not uncommonly do patients who have eaten recently and we would not cancel a case for a patient who had eaten. We would just make sure we didn’t do anything that ended up with them getting intubated.

Alan Jeremias, Stony Brook, New York: Personally, I am very comfortable with patients not being NPO for the procedure and never had a problem. However, to formally change the NPO policy in our lab is a much larger issue. John [Bittl], thanks for sharing your review of the evidence for the need of NPO in the setting of conscious sedation. How do you address the argument that it is difficult to predict who may have a complication requiring emergent intubation (albeit rare)?

Sam Butman, Cottonwood, Arizona: In our hospital, we are pretty much under the umbrella of anesthesia, which sets a policy for the entire hospital. Unfortunately their rules are not based on what “we” do, and our typical and variable level of sedation. I have been a big fan of minimal NPO, if not simply to avoid those occasional steep hypotensive events after some sedation or IC NTG [intracoronary nitroglycerin] in afternoon cases. Legally, until we reset the community standard, comfortable change may be limited, since it would difficult to find an anesthesiologist who would not support maximum periods of NPO, as they are the experts in the field. If we do go forward, let’s please make sure we have our ducks in order so that we do not end up taking a step backwards.

From Dr. Tom Bashore and colleagues, of the ACC/SCAI Guidelines4: “The committee feels that the patient’s need for overnight NPO is not always in the best interest of patient hemodynamics, and only a minimum NPO period of 3 hours is sufficient, unless conscious sedation will clearly be required. If conscious sedation is required, the NPO period is suggested to be at least 4 hours. The American Society of Anesthesiologists last published NPO guidelines in 1999, at which time they suggested 2 hours of fasting after clear liquids and 6 hours after a light meal. Adequate hydration remains an overlooked but important preparatory feature”.

The bottom line

I still agree with Dr. Bittl’s approach to dropping the NPO entirely and that his editorial3 provides strong support for this position. But for most labs, NPO will continue to mean no food for 6-8 hours before and clear liquids up to 2 hours before the procedure. I think patients can (and should) continue to drink all the way up to the procedure if they are thirsty. However, I recognize the reality of our administrative environment and also understand that most labs will continue to strict NPO rule adherence, probably in part out of fear of violating an outdated standard of practice which has the support of our anesthesiology colleagues.

References 

  1. Brady M, Kinn S, Stuart P. Preoperative fasting for adults to prevent perioperative complications. Cochrane Database Syst Rev. 2003;(4):CD004423.
  2. Soreide E, Eriksson LI, Hirlekar G, et al. Pre-operative fasting guidelines: an update. Acta Anaesthesiol Scand. 2005; 49: 1041-1047.
  3. Bittl, JA. A proposal to reduce contrast nephropathy: eliminate the NPO order. Catheter Cardiovasc Interv. 2014 May 1; 83(6): 913-914. doi: 10.1002/ccd.25482.
  4. Bashore TM, Balter S, Barac A, et al. 2012 American College of Cardiology Foundation/Society for Cardiovascular Angiography and Interventions Expert Consensus Document on Cardiac Catheterization Laboratory Standards Update: A Report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents. J Am Coll Cardiol. 2012; 59(24): 2221-2305. 

Disclosure: Dr. Kern reports he is a consultant and speaker for St. Jude Medical and Volcano Therapeutics, and a consultant for Opsens, ACIST Medical, Heartflow, and Merit Medical.