Pediatric Sedation Newsletter
February 2001
(A newsletter for all who provide sedation to children)
Departments of Anesthesiology and Pediatrics, Dartmouth Hitchcock Medical Center,
Lebanon, NH
Editors:
Joseph P. Cravero, MD (joseph.cravero@hitchcock.org)
George T. Blike, MD (george.blike@hitchcock.org )
Website: (http://an.hitchcock.org/PediSedation/)
Circulation = 1850
Our February newsletter includes a literature review concerning sedation for pediatric
gastroenterological procedures – an area of pediatric sedation that appears to be in some
flux at this time. We also include a review of two papers on pediatric sedation from the
recent Society for Pediatric Anesthesia Meeting in San Diego, California. We include
this as an invitation to the readers of this newsletter to send in descriptions of pediatric
sedation related abstracts and educational materials from any meetings that you attend.
My hope is that this will keep our readers from various fields aware of the research
activity taking place in other areas. Finally we have our monthly safety discussion in
which we review problems with undersedation for VCUG examinations in the radiology
department. This is a subject of great debate in our referral area and the subject of many
phone calls to our department.
Question: A question has been raised by a reader (Al Tagliavia, M.D) who would like to
ask the anesthesiologists who read this newsletter if they have found a problem with
laryngospasm when using LMA’s for sedation/anesthesia of infants. He would
specifically like to know if practitioners remove LMA’s while children are still deeply
sedated or if they wait until the child is awake.
As always we invite your comments and suggestions.
Literature Review:
Ketamine Sedation for Pediatric Gastroenterology Procedures. Steven M.
Green, Marquelle Klooster, Troy Harris, Elizabeth L Lynch and Steven G
Rothrock. Journal of Pediatric Gastroenterology and Nutrition. 32:26-33
January 2001
Description of the Paper: The introduction to this paper reviews first the rising popularity
of ketamine for emergency department pediatric sedation. The authors go on to comment
of the current state of sedation for pediatric gastroenterology procedures (which is quite
variable). While some gastroenterologists use minimal sedation for these procedures,
there is a growing trend to have general anesthesia for endoscopic procedures. The
authors site 5 previous papers that reported success with ketamine for endoscopic
procedures. Of note is the fact that there were no airway problems reported in these
previous studies. The current investigation was an effort to evaluate the incidence of
adverse effects of ketamine in this setting.
The study design was retrospective in nature. A review of five years of ketamine
administration by pediatric gastroenterologists for gastrointestinal procedures yielded a
series of 636 instances of ketamine administration. The primary procedure was EGD
(86%) and the primary route of administration was IV (98%). Total dose used was 1.34
mg/kg. Inadequate sedation occurred in 1.1% of the cases. Adverse events were reported
as laryngospasm (8.2%), emesis (4.1%), recovery agitation (2.4%), partial airway
obstruction (1.3%), apnea and respiratory depression in 0.5%. There were no “adverse
reactions” due to ketamine. Nearly half of the patients had a significant underlying
illness. All laryngospasm episodes occurred during upper endoscopy examinations.
Decreasing age was the only independent factor associated with laryngospasm. This
incidence was 13.9% in preschool patients.
The gastroenterologists were described as “skilled in airway management”. The
authors include detailed (somewhat hair-raising!) descriptions of the laryngospasm
episodes that occurred during the period that was examined. “The lowest oxygen
saturation was recorded in only 43 of 52 patients during laryngospasm, with a median of
70%”. One wonders what the lowest saturation was in the 9 other patients where this was
not recorded. Airway assistance was required in 37% of the patients while the others
improved with removing the endoscope and providing extra oxygen.
Other episodes (including an apnea episode that resulted in the patient requiring
intubation by an intensivist) are described.
In the discussion section the authors review the effectiveness of ketamine in producing
sedation/analgesia that is effective for endoscopic procedures and they cite the potential
problems associated with its use. The authors include a comment that ketamine is not an
anesthetic in the true sense of that word (see November Newsletter). They note the fact
that in this series no serious adverse outcomes were observed and that many of the
patients had comorbid states.
Comment: Dr. Green and his colleagues should be commended for performing this
retrospective review. The data certainly give us insight into the use of ketamine for this
type of procedure. The paper is most notable for the high incidence of laryngospasm and
partial airway obstruction that were recorded. Given that we know retrospective studies
are notorious for under-reporting incidents such as this, we can assume that the actual
rate of these problems was almost certainly somewhat higher than described.
Those of us who use ketamine often are well aware of the potential for laryngospasm,
particularly when manipulation of the mouth or airway is attempted. We find ketamine
an odd choice for upper endoscopy where stimulation of the structures surrounding the
larynx is almost unavoidable. A gastroenterologist using this drug would have to expect a
high rate of laryngospasm. After reading this paper we would find it hard to recommend
the drug for this purpose.
While there are no “adverse outcomes” reported, less than 700 cases were reviewed.
Anesthesia for these procedures (even in this population) should produce no more than 1
adverse outcome in several thousand cases. The lack of a bad event in this series does
little to reassure us that this drug is safe for endoscopy. If anything, the high frequency of
significant airway difficulties associated with the use of ketamine seems a strong warning
that this drug would provide us with an adverse outcome if a large enough sample of
cases were studied.
It is important to note that the one case in this series where intubation was required, a
critical care specialist was available to perform the intubation in what we believe is an
appropriate time period. This is a great example of how good rescue strategies are crucial
when delivering sedation such as this. The ready availability of expert airway assistance
is paramount in avoiding catastrophes in scenarios where sedation has produced a true
emergency.
JPC, GTB
Nitrous Oxide Sedation in Pediatric Patients Undergoing Gastrointestinal
Endoscopy. Laurent Michaud, Federic Gottrand, Patrice Ganga-Zandzou et
al. Journal of Pediatric Gastroenterology and Nutrition 28: 310-314 March
1999.
Description of the Paper: The authors begin this paper with a description of Entonox – a
50% nitrous oxide in oxygen mixture. The drug is known to be fast acting, not
metabolized, and effective for minor painful procedures. It is used by the parent medical
center for lower endoscopy examinations in adult patients.
The authors enrolled 38 patients between 5 and 17 years old in a non randomized and
unblinded manner to receive entonox alone as sedation for endoscopy. No topical
anesthesia was administered The physicians and nurses in the endoscopy suite rated the
procedure for efficacy, cooperation, drowsiness, and emotional status (on 1-3 scales for
each) after the procedure was completed. In addition the patients were asked to rate the
sedation for pain and stress on a 1-100 scale after the procedure was done.
The results revealed a fairly high rate of effectiveness (approx 90%) for the drug.
Physicians (not surprisingly) rated the children much more cooperative than the nurses in
the room did (92% vs 78% rated the cooperation good or better). In fact, 27% of the
children require physical restraint during upper endoscopy. Emotional status ratings were
similar to cooperation.
The patients were variable in their ratings of the sedation. As one would imagine,
upper endoscopies were much more likely to be rated high on the pain and stress scale
with a range of 5 to 100. Little detail is given on these data. A chart reveals that
screaming and crying occurred about 10% of the time. Patients who had previously
received midazolam said they would prefer entonox in the future.
There were no adverse events in this small sample. Side effects were minimal with the
most common being headache in 16%.
In the discussion section of the paper the authors note that their experience with
entonox compared favorably with the use of benzodiazepines and was much less
expensive than the use of general anesthesia. They suggest that future studies should
include local anesthesia to the oral pharynx in addition to entonox.
Commentary: Is the cup half full or half empty? The drug seems to work well for some
patients and not so well for others. (Perhaps careful screening of patients could give some
indication as to which patients would do better or worse based on their personality and
anxiety profiles). Is failure to achieve adequate sedation in 10% of patients, and a
moderate to severe agitation rate of about 25% acceptable? Each operator must answer
these questions for him/herself in the context of his/her own practice. Clearly the use of
topical anesthesia should improve the performance of this type of sedation in the future.
Methodologically we must point out that the endpoints used here were quite crude and
not validated measures. It is hard to know how consistent these findings would be from
one institution to another.
Finally, a study that uses relative measures (such as this one) must recognize what
basis of comparison the providers and patients have to judge their sedation experience
against. In this case all previous cases were performed with minimal midazolam
sedation. If the patients in this study had previously received really excellent deep
sedation for endoscopy, we likely would have found grossly different results on the
subjective measures of what the entonox experience was like.
JPC/GTB
For those interested in the Gastroenterologist’s view of pediatric sedation please see
Sedation for Pediatric Endoscopic Procedures by Vasundhara Tolia, John Petes and
Mark Gilger in the May 2000 issue of Journal of Pediatric Gastroenterology and
Nutrition.
Question: After reviewing this literature we think it would be interesting to know what
gastroenterologists are using for sedation around the country and around the world.
Please send us information on what is done in your institution and we will feed this back
in the next newsletter.
Abstracts from the Society for Pediatric Anesthesia Meeting Feb 23-25,
2001 San Diego California.
A Comparison of Intravenous Pentobarbital to Intravenous Pentobarbital
and Midazolam for Sedation of Children Undergoing Radiological Imaging.
Keira P Mason, David Surakowski, Victoria E karian, Linda Connor,
Paulette Fontaine, Patricia Burrows.
Study Description: The authors prospectively studied 1070 patients receiving sedation for
a variety of radiological tests including MRI scans, CT scans, and Nuclear Medicine
Scans. The pentobarbital (P) group received pentobarbital 2-6 mg/kg while the
pentobarbital-midazolam (P-M) group received 0.1 mg/kg of midazolam followed by 2-6
mg/kg of pentobarbital. Pentobarbital was titrated in 1-2 mg/kg doses until desired level
of sedation was achieved.
Six hundred and forty patients were enrolled in group P while 430 were enrolled in
PM. The groups were similar demographically. Time to sedation and time to discharge
were noted to be longer in the PM group (p = <0.001 for both). Adverse events including
paradoxical reactions, oxygen desaturation, and vomiting were not different between the
groups. The total dose of pentobarbital used between the groups was not different.
The authors concluded that these results indicate that the PM combination was not
superior to P alone and actually had a less favorable kinetic profile.
Commentary: While these patient numbers are impressive – I do not believe (from
reading the abstract) that the patient assignment was randomized or that the investigators
were blinded. With these flaws in mind, the study makes a good argument against
combining these drugs. Perhaps a pharmacologist could explain why a loading dose of
midazolam did not decrease the total amount of pentobarbital used for the studies.
Propofol Sedation in Pediatric Patients Undergoing Lumbar Puncture
and/or Bone Marrow Biopsy/Aspiration. Michael Seropian
Study Description: The records from one hundred and forty two procedures (evenly
divided between LP’s and one marrow biopsies) were retrospectively reviewed. Propofol
was used as the sole agent for sedation in all of the procedures. Records were evaluated
to determine the dose requirement of propofol and any side effects or adverse reactions
that occurred during each sedation. The method used for administration of propofol
included a 2-3mg/kg loading dose followed by 1-2 mg/kg doses as needed to control
movement during the procedure. Patient demographics, total drug used, sedation time,
recovery time, and any adverse reactions were recorded.
The author reports a failure rate of 0% and an adverse event rate of 0.2% (with one
patient experiencing O2 desaturation). The mean dose required for sedation for these
procedures was 5.58 mg/kg. The mean sedation time was 15.87 minutes and the mean
recovery time was 12.70 minutes. No apnea, airway obstruction, or hypotension episodes
were noted.
In the discussion section, the author points our a recent study by Hertzog et al. (see
previous newsletters) where a 12% rate of partial airway obstruction, 2% apnea rate, and
63% incidence of hypotension were noted.. The author suggests that the disparity
between this study and that of Hertzog et al. are related to the larger dose and (possibly)
the rate of administration of propofol in the later study.
Commentary: This is intended to be a pilot study for further investigations into the use of
propofol for this type of procedure. Clearly a retrospective review such as this can not be
used to make conclusions as to the rate of adverse reactions etc. It is interesting to note
the amazingly short recovery time to sedation time ratio for such a short procedure – a
phenomenon quite familiar to everyone who uses this drug regularly.
The study by Hertzog was prospective and vital signs were carefully collected. It is
not fair to compare the two studies in terms of rate of adverse reactions. Still the author’s
points concerning the manner in which propofol is given are important in bringing to
light some of the subtle aspects involved in administering any potent sedative hypnotic.
Close Call and Critical Incident Reports
We invite those receiving the newsletter to submit cases to this "Close Calls" section
aimed at the key safety issues associated with providing pediatric procedural sedation.
The cases have been "sanitized" such that the date, patient identifiers, institutional
identifiers, provider information, etc. will not violate the privacy of the patient or care
providers.
Case#5
A 3 year old child was referred to a urologist because of several episodes of urinary tract
infection. The urologist ordered a renal ultrasound and VCUG (Voiding Cysto Uretero
Gram). The child had had several catheterizations for urine cultures in the past and the
parents predicted that s(he) would “fight” the procedure. They were specifically
concerned that their child should not be held down to get the procedure done. The
radiologist reassured the parents that “we have performed hundreds of VCUG’s”…that
their concerns were unfounded…sedation was unnecessary… The day of the procedures
the ultrasound was accomplished without incident and the technician was able to talk
with the child throughout the procedure. In contrast, when the child entered the room for
the VCUG and saw the catheter s(he) screamed. For the next 90min the parents
perceived that the procedure team had to “catch” their child and hold him/her down.
additional people came to help with restrain due to the vigor with which the child fought,
They “forcibly” inserted the catheter and proceeded with the test. Although all forms of
persuasion were attempted, the child was “out of control” kicking, screaming, and
thrashing throughout the procedure. Afterwards, the radiologist informed the parents that
the difficulties encountered were rare and that the child would “forget” the experience.
The radiologist also stated that the risks of sedation for such a minor procedure were too
great. He went on to imply that the real problem was parental presence during the
procedure. The parents later reported that their child suffered nightmares, regression on
“potty training”, and behavioral changes for several weeks. They ultimately sought
professional psychological support for their child. Subsequent doctor visits and dental
visits have been very difficult (child begins crying and is uncooperative). The parents
have formally complained to the Chief of Radiology, the Medical Director, and the senior
management of the hospitals administration. They have threatened litigation. Ultimately,
the hospital has begun to offer sedation for VCUG’s and the parents have not taken
action, being satisfied that other children have benefited from their child’s negative
experience.
Comments:
This case has many features but we are going to focus on 1) “under use” sedation errors;
2) the phenomenon of “sensitization to procedures” and the anticipatory anxiety
associated with subsequent procedures; and 3) the relationship of quantity, quality and
cost in healthcare.
1) UNDER-use errors
Medical error can be broadly defined as the: “UNDER-use, OVER-use, or MISS-use of a
given medical therapy.” Sedation can and is used for VCUG’s. We have videotaped 4
VCUG’s at the Children’s Hospital at Dartmouth and 2 were accomplished in a manner
very similar to that described in this case. We contend that these cases represent “underuse” sedation errors. Sedation efficacy varies with the strategy used.
1. Non-pharmacologic preparation is effective in some cases, but has the highest
failure rate.
2. Many institutions use oral versed. The goal of this therapy is to produce amnesia
(the 4 cases we videotaped were performed with oral versed sedation). Often the
child resists and needs restraint, but it is hoped they will not remember the
experience. However in both cases we videotaped where there was severe
agitation, the children remembered the experience and developed symptoms
consistent with Post-Traumatic Stress Disorder post procedure.
3. We have had great initial success with a technique that includes; a) Child Life
preparation. This involves giving the parents and child age appropriate
information about what will be done and how along with a “homework”
assignment to lay in the bath tube supine and “pee” b) EMLA cream and an IV on
the day of the procedure. c) single bolus administration of Propofol by an expert
provider for the catheter placement d) emergence usually within 7-8 minutes with
the bladder full of contrast and encouragement to void e) discharge within 35-45
minutes after propofol dose when meeting criteria. This technique has been
embraced by our radiology department who have seen efficiency (through-put)
and patient satisfaction soar. Is this safe?? We must weigh sedation risks against
procedure risks without sedation to answer this question. Literature on anesthesia
and sedation supports the contention that the morbidity and mortality associated
with ultra-short acting IV sedation given by airway is similar to the risks of
driving your child to the hospital, or letting him/her eat hot dogs.
2) SENSITIZATION to pain and anxiety
This case illustrates that previously bad experiences to procedures can rapidly sensitize
children such that they recognize when they are about to have the procedure and they
(logically) try to avoid the procedure. In this case the parents predicted their child’s
response based on previous experience. Indeed the child had been doing well until s(he)
saw the catheter which triggered anxiety. We need to quantify the harm caused by
performing procedures forcibly. It is known that children can and do develop PTSD. We
do not know how often medical procedures that cause pain and stress produce PTSD or
the long-term sequelae.
It should be noted that desensitization occurs as well. Children that have to give
themselves insulin can be desensitized to “needle phobia” with needle play and repeated
good rather than bad experiences. Similarly, staff that perform necessary procedures with
techniques they believe to be “the best possible” become desensitized to the screaming
child and do what is necessary to get the job done.
3) QUALITY, QUANTITY, and COST
System engineers hold that if one optimizes a system for two of these parameters, the
third will suffer. One of the lessons in this case is to remind us of the tension between
patient through-put (Quantity), the expense of medical care (Cost), and the most effective
care with the least harm (Quality). We believe that if one optimizes medical care systems
to handle as many patients as possible on the cheapest budget, quality (patient safety
from under-use, over-use and miss-use) will suffer. Several barriers exist that predispose
most medical care systems to under-treat procedural pain and stress. A) demand for
procedures often exceeds capacity. Our demonstration of the “what is possible” for
VCUGs clearly involves sedation resources that are not required if no sedation is used.
Our anesthesiology department does not currently have the capacity to have
anesthesiologists provide sedation for all VCUGs. As an academic hospital, if we don’t
have this capacity, I think it unlikely that community and/or rural hospitals are any better
off. Having to wait for a test may increase harm due to delayed diagnosis and treatment
of the condition being studied. B) Cost of “ideal” care may be prohibitive. Having an
expert team use IV propofol and the Child Life specialists prepare the patient may add as
much as ~$500.00 to the cost of VCUG. In addition, reimbursement varies on payer
mix.. Even when we have the technology to do better, we may not be able to afford this
level of “quality” in medical care. C) Quantity and cost are easier to measure than
quality in healthcare. For this reason, our systems will be biased to optimize aspects we
are measuring. On an aircraft carrier every landing is scored and scores below a certain
number trigger a review for what went wrong and how to do better. We need to start to
“score” each and every procedure and its associated strategy for managing associated
pain and stress. We cannot manage or improve that which we do not measure.
Unfortunately, the best we can hope for is a rational balance between quality, quantity
and cost.
Summary
No trivial answers to these complicated issues. Hopefully by reviewing cases that pose
special demands, innovative solutions will be discovered. Thanks for the reports that are
being submitted, please keep them coming so that we all can learn from them.
Any input on how VCUG’s are accomplished in your institutions would be welcome.