Inside this Edition

Upcoming Pediatric Sedation Conference

Parental Presence:
The discussion

Literature Review:
Case-series of nurse-administered nitrous oxide for urinary catheterization
in children

Newsmakers Interview:
Judy Zier, MD
Children’s Hospital and Clinics of Minnesota

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Sedation Newsletter Newsmakers Interview

To continue the ongoing series of interviews with individuals at the forefront of the discipline of pediatric sedation, Judy Zier MD of the Children’s Hospital and Clinics of Minnesota has graciously provided some detailed insight into the pediatric sedation program there, in particular, the nurse administered nitrous oxide program.  Her interview with us (by email):

Tell us about the current scope of pediatric sedation services available at Children's.
Our group of intensivists covers sedation services on both the Minneapolis and St. Paul campuses of Children’s Hospitals and Clinics of Minnesota. We sedate mainly for radiology (MRI, CT) and for hematology/oncology (LP’s and bone marrow biopsies) as well as a few other procedures such as EEG’s and BAER’s. All together, we do about 2,500 propofol sedations per year.  We also provide coverage for the nurses administering minimal sedation (e.g., oral versed, chloral hydrate, nitrous oxide) by discussing the patient, ordering the sedation, and remaining available for any issue which may arise with these patients.

How did the nitrous oxide program at Children's evolve and develop?
It all started when I was sitting in my dentist’s chair waiting to have my teeth cleaned. I looked up at my hygienist’s nitrous oxide certificate and asked her about it. “Oh yeah,” she said, “works great with kids.” And I thought, here I am, a pediatric intensivist. I give propofol, I give ketamine, why can’t I use nitrous oxide? About the same time, we got a new CT scanner suite and the sedation nurses were bumping their heads on the nitrous port that hung from the ceiling. The scanner was faster than before, so they were asking, “Why can’t we try nitrous for some of these shorter scans, rather than starting an IV and using propofol?” Unfortunately, there wasn’t a great way to learn how to use nitrous for medical applications, so we went to dental school to learn.

Once we got the basic nitrous education, we picked a patient population that we figured would benefit from nitrous oxide and who we thought wasn’t well served with the current process. The nurses weren’t very satisfied with oral versed for the kids getting voiding cystourethrograms (VCUG) or radionuclide cystograms (RNC). The tests would take only about 10 minutes, during which the kids would often be crying and belligerent despite the versed and then they would be sedated for an hour or more afterward. The alternative was to use brute force to hold down the kids for their test which wasn’t very satisfying either. So we figured that nitrous couldn’t be much worse for these children than what we were doing already.

Our first patients were very illustrative of what can and cannot be done with nitrous. Fortunately, our first patient was a 10 year old boy who really was giggling with the “laughing gas.” He was perfectly relaxed for the catheter placement, then we let the nitrous wear off and he went off for his RNC. Shortly thereafter, we heard screaming from the nuclear medicine room and thought, “What have we done? At least the versed lasts through the test!” Turns out that he was having pain with voiding after the test was done. We brought him back into the sedation area, gave him more nitrous until he voided (which he did without difficulty) and then sent him home with a smile on his face (whew!). When his mom asked, “Why didn’t you have nitrous when my other son was here last year?” we knew we were on the right track. The second patient was a 10 year old girl who was here for her third annual test for known reflux and was actually looking forward to the versed. She was disappointed to try nitrous, but her mother was interested in something that didn’t last as long. We tried it, but the girl was so upset to begin with that we couldn’t even get her to relax and go with it. Lesson learned: distraction is an integral part of the process and you have to have buy-in from the patient.

Once we got the hang of using nitrous for VCUG’s and RNC’s, the program expanded to other tests in radiology and then to other areas of the hospital, including the ED and hematology-oncology clinic.

How did you all go about addressing the nursing administration component and nursing practice issues?
When we began to look into developing a program, a rumor began to fly about that we were going to “make nurses give anesthesia” so we thought we better address the scope of practice issue head-on. We met with representatives from the Minnesota Board of Nursing who admitted that they were unsure whether nitrous administration fit better in a CRNA role rather than an RN role. We made several arguments, namely, that 1) nitrous oxide has a MAC of 104%, so general anesthesia is really not an issue even though nitrous is classified as an anesthetic gas; 2) dental hygienists can be licensed in the state of Minnesota for nitrous administration and a nurse would be more capable of handling a sedated patient than a hygienist; 3) nurses give more potent sedatives all the time (e.g., chloral hydrate, pentobarbital) with a physician’s order but without a physician’s presence as long as appropriate policies and procedures are in place, so nitrous would fit this model, it just happens to be delivered in a gas form rather than an oral or IV form.

I firmly believe that our program is so successful because the nitrous is in the hands of the nurses rather than the physicians. The nurses are much more patient, spending more time with the child and family before the sedation, getting them acquainted with the mask and equipment, providing appropriate distraction. I think a lot of our physicians would have the tendency to put the mask on, be disappointed that the child doesn’t fall asleep, declare it a failure, and move on to bigger guns.

What types of patients are receiving nitrous, and how are they selected?
We started with patients that would have otherwise gotten oral versed since the level of sedation is similar. So we started with the bladder catheterization for VCUG’s and RNC’s. Our PICC lines are placed by interventional radiologists who prefer sedated patients, so we have been using this for the adolescents undergoing this procedure. One of the hematology/oncology groups has been using IV narcotic plus IV versed for LP’s and has started using nitrous instead for quite a few of their patients. It’s great for difficult IV starts because of the vasodilatation “side effect.” We are also using it for a variety of other procedures, including IM botox injections for spasticity and intra-articular joint injections.  The ED uses it for a variety of procedures like laceration repair, IV starts, foreign body removal, shoulder/elbow reductions and I & D of skin abscesses.

A lot of our urologic imaging is ordered by the urology groups, who frequently order their studies with sedation. Nitrous has become the default for “with sedation” for these procedures. Nitrous is also the default for adolescent PICC lines unless the radiology sedation nurse thinks the child is too apprehensive and would do better with deeper sedation. The radiology sedation nurses will often ask to try nitrous for other tests, like CT scans, if they think the child is a good candidate based on their initial impression of the child. In the ED, it’s up to whoever is doing the procedure to consider nitrous, as well as availability of a “nitrous nurse” as not all of the ED nurses are trained in nitrous administration, yet.

Are you all using nitrous in combination with other agents?  How does the sedation physician then become involved?
The nurse-administered, minimal sedation protocol is nitrous only. These patients are not fasted except for a recommendation for a light meal only. Physicians do not have to be in the room. That said, nitrous alone is not enough analgesia for some of the more painful procedures done in the ED, so occasionally kids will get an analgesic in addition to nitrous. In that case, the sedation is shifted into our moderate sedation policy which calls for closer physician presence and more frequent vital sign monitoring.

In your experience, what are the benefits of nitrous versus other available agents/regimens for these patients?
The beauty of nitrous oxide is its rapidity in both onset and dissipation of effect. For bladder catheterization, kids are ready within a few minutes and are back to baseline within about 5 minutes and can move on to the rest of the test. I have had parents tell me that their child was not back to their normal self until more than a day after getting oral versed. Kids can go back to their regular activities or school.  Parents can go back to work after the procedure rather than taking care of a still-somewhat-sedated child.

It’s also a good drug. Nitrous has analgesia, unlike some other sedatives. This helps with procedures like IM botox for spasticity, although I still would recommend using topical EMLA or Elamax with the nitrous for this procedure. Nitrous also has decent amnesia, which I didn’t really believe until I saw a girl sit bolt upright during an upper extremity EMG which required putting a needle into her thenar eminence. When that part was finished, she continued getting nitrous for the surface electrode portion of the EMG and by the end did not recall the needle-stick.

Unfortunately, there are parents and providers who assume that since a child is getting “gas” that the child will fall asleep and are disappointed when this does not happen. It is important to match everyone’s expectations to the actual capability of the sedative. Nitrous is most powerful when paired with good distraction, whether it is a story told by a parent or nurse, or a video to watch. Placing a mask on the nose of a teenager and saying, “Do you feel it yet?” just doesn’t work well if the patient is very anxious. You really need that soothing distraction component. There are some children who don’t get much effect from nitrous regardless of the distraction and the staff need to be prepared for this as well.

How do you choose your starting "dose"?  How do you titrate this "dose" over time?
In dental school, we were taught to start at 100% oxygen and titrate the nitrous up to desired effect, with adults doing well in the 30-40% range. Most of the “medical” reports of nitrous use, however, are from areas of the world that use a premixed 50% nitrous/50% oxygen mixture. Before we started our program, we talked to some pediatric dentists for recommendations. We were told that for uncooperative toddlers, we should consider starting at 70% (maximum a dental flowmeter can deliver) and then titrating down. We decided to start everybody on 70% with the plan on titrating down, but since the catheterization for VCUG’s and RNC’s is over so quickly everyone was getting 70% for the whole procedure. Over time, we have found that kids have more nausea at 70%, especially if the procedure takes more than 10-15 minutes (like a PICC line). Now, most patients start at ~60%, allowing titration either up or down depending on the response of the child.

What types of side effects are you all seeing?
Nausea and vomiting are the most common. We also see some diaphoresis, which can be a precursor to vomiting. There are occasional hallucinations, but not the bad kind that you can see with ketamine. Some kids say they feel like they have had a dream, but I wouldn’t really call that a side effect. We have had a couple of kids develop oxygen saturations less than 90%. One was a tracheostomy-dependent child who has “breath-holding” spells even without sedation. The other 2 were neurologically impaired children who had baseline issues with gagging and secretion clearance. We also had one child who had a brief seizure shortly after the nitrous was discontinued. There is a case report of a child with nitrous-associated seizures; however, our patient was receiving 100% oxygen at the time of the seizure.

Could you talk a bit about the equipment you all are using, facility needs for set up, etc.?
We use a standard “off-the-shelf” dental flowmeter and equipment. Our flowmeter is manufactured by Porter Instruments. We use their stand and rubber goods as well. We use a nasal hood manufactured by Accutron because it seems to fit over the nose and part of the mouth better. We don’t use a dental chair, so placing the mask and wrestling with the tubing is a bit of a challenge since it is made to drape over the back of a dental chair with a patient in a supine position.

In areas where we have nitrous plumbed into the wall (radiology, ED) we plug into the wall nitrous. In other areas, we use a portable tank stand (also from Porter) to hold the nitrous. We don’t do sedation anywhere there isn’t oxygen available, so we always plug into the wall oxygen. Fortunately, our wall vacuum has been found by our facilities department to be acceptable for removal of nitrous so we either hook up the scavenging system to waste anesthesia gas disposal (where available) or hospital vacuum. I have been in one hospital where the vacuum was vented to a drain in the lower level of the building. This was NOT suitable for nitrous evacuation, so plumbing had to be installed for scavenging.

How have you addressed initial and ongoing education and credentialling for providers?
We have education programs geared both at the nurses, who are the primary administers of nitrous oxide, and at the physicians and advanced practice nurses who order it. Nurses get a full day course which covers pharmacology, toxicity, policies & procedures, equipment, environmental safety, and administration techniques. They also must do hands-on administration in a mentored environment doing at least 3 administrations start-to-finish and be signed off by a “super-user”.

Provider education is a shorter, on-line course. Anyone, including housestaff, can order minimal sedation at Children’s, but I worried that not everyone would be aware of the contraindications that are specific to nitrous (e.g., expansion of pneumothorax or bowel obstruction), so I asked for specific nitrous credentialing. Since we have a nurse-administered program, the provider education is a distillation of the nursing course with an overview of the essentials. Providers take a post-test and are given a hands-on overview of the equipment before they are credentialed to order nitrous.

What has your interaction with your anesthesia colleagues been regarding this service?
Most have been extremely supportive. A few were a bit skeptical until they saw all the safeguards we put into place (e.g., standard order sheets, scavenging system). For a few, it helped to have the head of their group say, “Hey, do you want to sit in radiology and give nitrous to kids for VCUG’s all day? We have enough to do…” Now nurse-administered nitrous is just part of the landscape and it’s not a big deal.

How are you all billing for these patients?
Short answer? My group isn’t billing for these patients. We discuss them with the nurses and sign the orders, but don’t actually see the uncomplicated ones (e.g., VCUG or PICC line patients), so don’t generate a professional fee for the group. The hospital struggles with this, because we have been sticking to our guns that this is minimal sedation (which it is) but that is “unbillable”. Since starting the nitrous program, Children’s has seen increased productivity (nurses spend less time with a nitrous-sedated patient than an oral versed patient) as well as an influx of patients who have heard we have it available, so the system has supported the program despite this issue.  I know that ED groups at other hospitals have charged the moderate sedation codes for nitrous.

What have been the biggest challenges in establishing this program?  What are its biggest advantages?
I knew that starting a program from scratch in a hospital system would be a lot of work, but I was too naïve, thank goodness, to know how many little details it would entail. Fortunately, our initial working group had contacts in key areas, like biomed and purchasing, and we had good administrative support. It’s still a work in progress as we keep tweaking the educational program, train new hospital areas, try new procedures. But we now have a lot of supporting documentation (e.g., order set, parent ed sheets) that we would be willing to share to make the process easier for others starting a program.

The biggest advantage? It’s just the right thing to do. As physicians, I don’t think we realize the traumatic impact of some of the procedures we order. I have had radiologists ask me why we would bother giving sedation for bladder catheterization when it’s “not even very painful,” while on the other hand I have had physicians come up to me and thank me for putting the program together after telling me VCUG horror stories from their own childhood. Parents whose children have gotten procedures both before and after the nitrous program ask why nitrous isn’t available everywhere. If you set up the program right and screen patients correctly, nitrous sedation is safe and ridiculously simple.

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Joseph Cravero MD
George Blike MD

Departments of Anesthesiology
and Pediatrics,
Children’s Hospital
at Dartmouth,
Dartmouth Hitchcock
Medical Center,
Lebanon, NH

Editors Note:
Many thanks to guest
editor Trish Scherrer MD
from University of Virginia
Peds Critical Care,
who was instrumental
in putting together
the Nitrous Oxide review article and the interview
that are featured in
this issue.
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