EDITORIAL

Brave New World: do we need it, do we want it, can weafford it?

In this issue of Pediatric Anesthesia, Drs. Green and

Mason question the practicality of current sedation

guidelines pointing out the ongoing controversy

regarding who should provide sedation and what skills

are necessary (1). They are concerned that ‘patient

responsiveness-based’ guidelines are too subjective. We

agree that measuring depth of sedation remains an

imperfect science at best and that better codification of

risks and matching these with the skills of the sedation

provider can and should occur. Green and Mason

offer new thoughts on how improvement in the safety

and availability of quality sedation services may be

realized in the future. They should be congratulated

for their original thinking; however, we have funda-

mental disagreements with their approach. Therefore,

we will first review the development of the current

‘sedation depth’-based guideline and then examine the

Green and Mason proposal.

The first sedation guideline was introduced by the

American Academy of Pediatrics (AAP). This guide-

line was developed prior to the use of pulse oximetry

or capnography outside the operating room (2). There

was a need to establish a systematic approach to pro-

vide safe sedation at a time when the tools that we

now consider routine were not available. The guide-

lines were a product of the consensus of experts from

multiple specialties who were involved with sedation

practice. The definitions for so-called conscious seda-

tion and deep sedation were based on patient

responses: ‘conscious sedation’ implied a purposeful

response to verbal command or a painful stimulus,

whereas ‘deep sedation’ implied no response and/or a

purposeless response to a painful stimulus. Recommen-

dations for monitoring and oversight were based on

the estimation of the depth of sedation. Safety was (by

necessity) assured by relying upon the vigilance and

diagnostic skills of the practitioners providing seda-

tion. In fact, the same line of safety-related thinking

that had improved outcomes in anesthesiology by

orders of magnitude was applied to those providing

procedural sedation (regardless of their specialty)

through the widespread adoption of sedation guide-

lines. The success of this strategy is found in the cur-

rent level of sedation performance. Indeed, following

the most recent AAP guideline (3), several relatively

large studies involving over 100 000 pediatric sedation

encounters have documented a remarkable safety

record for pediatric sedation delivered by a variety of

specialty providers when appropriate patient selection

is matched to the skills of the practitioner (4,5). Out-

comes may be quite different if systematic care is not

provided (6,7).

Over the past 25 years, there has been an amazing

explosion of very expensive diagnostic technology and

with it increasing demands to provide sedation and

patient immobility (and at times breath holding) to

allow successful completion of the procedure. Often,

the sedated patients are in dark, poorly accessible,

remote locations. The demand for high-quality seda-

tion services comes from many sources including hos-

pital administrators, insurance companies, and medical

specialists; failed sedations are no longer acceptable as

this increases costs and frustrates parents. To optimize

the utilization of expensive diagnostic equipment and

reduce the ‘pay-off’ time, throughput and efficiency are

major driving forces for procedure-oriented depart-

ments. Potent sedatives such as propofol offer

decreased ‘sedation failures’ compared with longer-act-

ing, less-potent, alternatives. In addition, given the

often limited space for presedation assessment and

postprocedural recovery, short-acting drugs with rapid

onset and offset are preferred over medications with

slow-onset and long ‘hangover’ times. However, in

inexperienced hands, rapid-onset medications have the

potential to introduce a sedation ‘roller coaster’. Un-

dersedation with coughing and undesirable movements

may be followed within seconds by oversedation, respi-

ratory depression, airway obstruction, or hemodynamic

instability. The use of rapid acting drugs requires

comprehensive pharmacologic knowledge, constant

vigilance, and the appropriate skill sets to immediately

respond to unexpected events, i.e., the ability to rescue

the patient.

Just as the technology has evolved, so have the AAP

sedation guidelines. In the years following the first

guideline, it was clear to the hundreds of individuals

(from many pediatric specialties) who helped in their

development that it made no sense to determine

responsiveness to verbal command or tactile stimula-

tion every 5 min to ascertain their sedation level.

Therefore, the most recent AAP guideline stated that

any child under age 6 must be assumed to be deeply

sedated. The sophistication of the monitoring and the

skills of the sedation provider must match this level of

sedation (3); all providers must have advanced airway

management skills so as to be able to rescue the child

from an adverse event. The routine use of capnogra-

phy was ‘encouraged’, but not mandated because the

Pediatric Anesthesia 21 (2011) 919–923 ª 2011 Blackwell Publishing Ltd 919

committee was unable to find adequate evidence base

to make this a requirement. In addition, the guideline

stressed the importance of human simulation for train-

ing sedation providers and the collection of quality

improvement data. They also emphasized the need for

a ‘time-out’ to assure proper type and site of the test

or procedure just as in the operating room. Emphasis

was placed on the need for an independent observer

whose ‘only responsibility was to observe the patient’.

For more complex cases, it was recommended that

consultation be made with an anesthesiologist, intensi-

vist, or emergency medicine physician because each of

these specialties has the appropriate skills necessary for

patient rescue. Other organizations such as the Ameri-

can Society of Anesthesiologists, the Joint Commis-

sion, and the American Academy of Pediatric

Dentistry had similar concerns and developed sedation

guidelines which evolved, so that all four organizations

embraced a new nomenclature. ‘Minimal sedation’ was

equivalent to the older term ‘anxiolysis’, ‘conscious

sedation’ (an oxymoron for children) (8) became ‘mod-

erate sedation’, while deep sedation and general anes-

thesia maintained the same definitions (3,9–11).

Although as Green and Mason state, practitioners of

different specialties may quibble over the difference

between ‘moderate’ and ‘deep’ sedation or ‘deep’ seda-

tion and ‘general anesthesia’, everyone involved in this

process agrees that there are differing levels of sedation

and that the risk to children increases with the depth

of sedation. Green and Mason correctly point out that

these definitions can be confusing. Clearly in practice,

it has been shown that in the emergency room (and

likely many venues), the intended level of sedation and

that actually achieved is not the same; many children

are being sedated to a greater degree than intended,

while others are undersedated (12).

The authors are critical of current sedation guide-

lines stating that the ‘primary disadvantage to a

responsiveness-based continuum’ is its subjectivity and

‘failure to incorporate objective data’. We agree that in

special situations, the assessment of responsiveness is

impractical and counterproductive. However, contrary

to the implications of Green and Mason, none of the

guidelines state that one must poke or prod the patient

to ascertain their level of sedation. When the AAP

guideline was initially constructed, it was understood

that some children might be so lightly sedated that

such misguided management would defeat the entire

purpose of the sedation and wake the children up. The

intent of the ‘purposeful response to verbal command

or light stimulation’ language is to reassure the seda-

tion provider that if the patient is observed to be inter-

active during a procedure, there is very little likelihood

of an adverse sedation event related to airway obstruc-

tion (13,14). On the other hand, if the patient is unre-

active to a painful stimulus (e.g., a bone marrow

biopsy), then there is a high likelihood that they have

progressed either intentionally or unintentionally to a

greater depth of sedation and even perhaps to the state

of general anesthesia. This then provides everyone a

warning that greater vigilance is required concordant

with this state of sedation. We certainly agree that

such interactions are not possible in situations such as

the care of infants, those with neurological or verbal

impairments, and those undergoing specific procedures

such as an MRI where movement would compromise

the study. It is for this very reason that the AAP

guideline clearly states that an independent observer is

needed (3). Thus, the basic hypothesis of the Green

and Mason proposal is flawed. The subjectivity of level

of consciousness assessment is trumped by the objec-

tivity of continuous physiologic monitoring by an inde-

pendent observer. There is no counterproductivity

involved as Green and Mason suggest.

Green and Mason propose a five-step process for

developing an objective risk assessment tool for seda-

tion (ORATS). They would replace the current, ‘mini-

mal, moderate, deep sedation, or general anesthesia’

with the levels of escalating risk, e.g., 1 = <1/10 000,

2 = <1/1000, and 3 = <1/100, and they propose

that a specific adverse event (to be decided by commit-

tee) could be a surrogate marker (to be identified)

which would predict risk, i.e., the ‘new taxonomy’.

The example they use is ‘what is the risk of clinically

important ventilatory depression occurring within the

next 2 min based on current objective physiologic

parameters?’ How would such an alarm alter the inevi-

table need to have the skills to rescue the patient? We

assume that the authors are proposing a better integra-

tion of all monitors to provide an even earlier warning

than those provided individually by currently used

monitors. The author’s objective computer-driven algo-

rithm monitor would continuously assess physiologic

responses to sedating medications and would be rap-

idly responsive to changes in patient condition. If risk

for an adverse event has increased 10-fold (they pro-

pose airway compromise), then an alarm would sound;

conditions would be updated at 2-min intervals. Such

an audible alert of possible impending danger could be

extremely useful. Those of us who practiced prior to

pulse oximetry remember how the changing tone pari

passu with changes in oxygen saturation changed the

dynamics in the operating room. As soon as the satu-

ration began to fall, everyone’s head was turned to

find out whether the patient was okay. The anesthesi-

ology community has long searched for the ‘Holy

Editorial

920 Pediatric Anesthesia 21 (2011) 919–923 ª 2011 Blackwell Publishing Ltd

Grail’ of a ‘depth of sedation or depth of anesthesia’

monitor. We applaud Green and Mason’s advocacy of

capnography as the future of sedation monitoring.

Unfortunately, their advocacy of continuous EEG

monitoring is a bit premature as this has been shown

to be quite variable from drug to drug, with different

age patients especially those under 1 year and, in par-

ticular, of little use during ketamine, opioid, or barbi-

turate sedation (15,16).

Additionally, the monitoring array that Green and

Mason propose would likely be difficult to develop for

the MRI (monitoring compatibility, particularly EKG)

and during procedures involving the airway such as

upper G.I. endoscopy or dental procedures where

instrumentation and rubber dams may compromise

airway patency and changes in head position would

and do change the veracity of carbon dioxide samples.

Likewise, there are some procedures where a degree of

movement is tolerated and others where such move-

ment would trigger the provider to deepen the level of

sedation. It is not at all clear that an algorithm could

be written that would be able to stratify risk any more

exactly than several orders of magnitude.

While we completely agree that improved monitor-

ing techniques will ultimately improve safety, we find

it overly simplistic that physiologic monitoring alone

can predict minute-to-minute risk. Risk during and fol-

lowing sedation is related to the unique combinations

of patient, procedural, and provider factors. Many

children have significant coexisting illnesses. The same

set of physiologic parameters that would predict risk

in a child with congenital heart disease, reactive airway

disease, or obesity would likely not be predictive in a

child with no medical problems. More importantly, by

its very nature, procedural sedation for children

involves procedures. Interventions such as bronchos-

copy and endoscopy create risks in and of themselves.

The physiology of a patient, as measured at one

moment in time (no matter how sophisticated the

monitor), cannot predict risk in the next minute of the

case caused by placing a video scope through the glot-

tis or into the esophagus. In addition, medication

errors may occur at any time and drug–drug inter-

actions may result in a partial or actual drug overdose.

It simply makes no sense to grade the future risk to a

patient based simply upon the patient state at one

moment unless one can guarantee that all conditions

in the case will be unchanged going forward. At best,

the objective risk assessment tool for sedation sug-

gested by Green and Mason could only be used as a

rough guide of patient risk taking into consideration

the context of the patient who is being sedated, the

procedural conditions, and the provider interventions

at that moment in time. Its usefulness in predicting

future events and specific skill sets required would

likely be only marginally more accurate than the

imperfect sedation depth estimations advocated by cur-

rent guidelines. As with the traditional sedation guide-

lines, safety in their system would be heavily

dependent upon the ability of the sedation provider to

analyze the sedation encounter and override the algo-

rithm-based assessment based on his/her assessment of

all of the possible evolving confounders. Examining

safety issues for pediatric sedation requires a mathe-

matical ‘complex system’ rather than a predictive sys-

tem that lends itself to the relatively straightforward

modeling that Green and Mason suggest (17). An

accurate risk modeling system would have to include

separate models for the complex interactions of indi-

vidual patient physiology, the impact of the procedure,

individual drug effects (including patient-to-patient

variability), drug interactions, dose errors, provider

skills, and provider performance and then calculate

risk frequencies for the thousands of possible combina-

tions that these models would generate.

It is unfortunate that Green and Mason seek to

introduce a new taxonomy that is not appropriate for

all drugs currently used for sedation and wish to have

some drugs exempted from the development of this

‘new taxonomy’. Dr. Green’s own research has

demonstrated that approximately 1–2% of children

develop airway obstruction, laryngospasm, or apnea

when sedated with ketamine (18–21); we do not

understand why or how ketamine should receive its

own separate ‘dissociative state’ category and be

exempt from the new taxonomy because potentially

life-threatening events occur with some degree of pre-

dictability (22,23). Likewise, Green and Mason pro-

pose that dexmedetomidine should be exempt. At

present, we have inadequate experience to make any

safety statements about this drug particularly, because

Dr. Mason’s case series has shown that high-dose

dexmedetomidine has minimal effect upon the EEG

(24) but is associated with occasional incidents of

severe bradycardia (25). Furthermore, attempts to

correct such slow heart rates with glycopyrrolate are

associated with severe hypertension (26). We simply

do not know enough about this drug and its inter-

actions with other sedating medications to suggest

that it deserves an exemption. The ‘new drug exemp-

tion’ is reminiscent of an attempt by pediatric neurol-

ogists 20 years ago to have chloral hydrate exempted

from the AAP sedation guidelines until it was demon-

strated that chloral hydrate overdoses or interactions

could occur and had resulted in deaths and neurologic

injury (14).

Editorial

Pediatric Anesthesia 21 (2011) 919–923 ª 2011 Blackwell Publishing Ltd 921

Perhaps the most disturbing aspect of the Green and

Mason proposal is the idea that the current guidelines

and definitions of sedation have led to confusion and

difficulty in determining which providers should deliver

each level of sedation. This amounts to blaming the

messenger. The guidelines do not determine or even

suggest who should be administering sedating medica-

tions; rather, they are intended to provide a roadmap

to safety. If the sedation community were successful in

coming up with a system such as Green and Mason

suggest, new arguments over what level of predicted

risk requires a given set of critical competencies would

simply replace the current arguments over what level

of sedation requires a given set of training or creden-

tials. The drug effects upon the central nervous, respi-

ratory, and cardiovascular systems are the same

regardless of who administers the drugs and in what

venue the patient is sedated. It is not the drugs or the

patient population; rather, it is the skills of those

administering the drugs and their training and prepara-

tion for potential rescue should a patient prove to be

unusually sensitive to a medication or should a medi-

cation error occur (13,14). The problem here is not

with the guidelines, but the need for institutions, regu-

latory bodies, and national societies to grapple with

the idea of what represents critical competencies for

administering sedation to children or adults. Doubt-

less, this will require discarding petty differences of

opinion and the adoption of a laser-like focus on

patient safety and the need to define which skills and

training are absolutely necessary to provide this care.

In summary, we agree that it would be wonderful to

be able to integrate multiple physiologic parameters as

an ongoing assessment of patient well-being; however,

the implications of this would be that every sedated

patient would require a new (and likely very expensive)

device. The addition of significant cost in an era of

decreasing resources is unlikely to be acceptable for

most care systems. This is particularly problematic

because the combination of continuous pulse oximetry,

heart rate, and capnography and intermittent monitor-

ing of blood pressure have ushered in an era of safe

anesthesia and sedation. The only argument for an

entirely new system of monitoring would be the possi-

bility that these monitors would allow less-expensive

and less-qualified sedation providers to provide care.

Sacrificing human vigilance, experience and training

for innovative technology is misguided. While there is

absolutely no doubt that more work is needed in

developing depth of sedation monitoring, the primary

benefit to our patients lies elsewhere. To best care for

them, we need robust research into how we assure

their safety by training providers of sedation to recog-

nize the adverse physiologic changes they may create

with sedation. We must assure that they have the skills

to manage these negative perturbations when they

arise. Green and Mason are proposing a Brave New

World: But do we need it, do we want it, and can we

afford it? We believe that the extraordinary sums of

money and effort required to produce the reliable

monitors they propose should instead be invested in

improved training for sedation providers (such as

human patient simulation) and the development of bet-

ter quality improvement data collection technologies

for large-scale studies and analysis.

Charles J. Cote1

Joseph Cravero21Division of Pediatric Anesthesia,

MassGeneral Hospital for Children,Department of Anesthesia,

Critical Care and Pain Management,Massachusetts General Hospital,

Professor of Anaesthesia,Harvard Medical School,

Boston, MA, USA2Department of Anesthesiology,

Children’s Hospital at Dartmouth,Professor of Anesthesia and Pediatrics,Dartmouth Hitchcock Medical Center,

Dartmouth Medical School,Lebanon, NH, USA

Email: cjcote@partners.org

doi:10.1111/j.1460-9592.2011.03647.x

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Editorial

Pediatric Anesthesia 21 (2011) 919–923 ª 2011 Blackwell Publishing Ltd 923