Newsmaker Interview
Dr. Mick Connors
Children’s Hospital of Eastern Tennessee

Harvard Sedation Service Conference San Francisco

Gravenstein D, Berkenstadt H, Ziv A, Shavit I, Keidan I, Sidi A. Supplemental oxygen compromises the use of pulse oximetry for detection of apnea and hypoventilation during sedation in simulated pediatric patients.
Pediatrics. 2008 Aug;122(2):293-8

Literature Reviews

Davis CL. Does Your Facility Have a Pediatric Sedation Team? If Not, Why Not? Pediatric Nursing/ July-August 2008. Vol.34. No. 4

Abstract Excerpted: Children’s hospitals across the country should consider the formation of pediatric sedation teams (PST’s) for both inpatient and outpatient pediatric procedures.  As specialization increases and parents become more intune to available options, teams that focus on the alleviation of pain and providing a more pleasant procedural experience will become increasingly important to parents when choosing a facility.  Regarding facility benefits, PST’s can assist to improve both patient and parent satisfaction, and allow for the relocation of procedures to ambulatory care settings or alternative pediatric inpatient suites.  PSTs can also improve cost effectiveness when sedation is involved in decreasing the overall length of stay in procedure rooms and recovery areas, decreasing complications related to less experienced providers of pediatric sedation, and also decreasing incomplete procedure rates.  Parents can be attracted by such specialized teams, viewing them as a sign of organizational excellence in the care of children’s health.

Comment:  OK – so this is not a prospective randomized trial such as we like to discuss in this newsletter.  It is not even an exhaustive review of this topic.  It is however, a really nice discussion of a topic (or presentation of an argument) that has not been covered this plainly in any format previous to this article that we have come across. It is true that other authors (including these editors) (1) have made the case for sedation services as part of larger reviews of pediatric sedation, but we are unaware of an editorial or review that so unashamedly and accurately makes the case for expert sedation PST services.  As the author very correctly points out, the sedation service is a reasonable answer to many of the problems that face children’s hospitals. In terms of patient care (our primary interest), the paper highlights some of the data that has developed supporting the idea that both safety and effectiveness of pediatric sedation are improved through the formation of a PST.  She also spends a significant amount of time reviewing the economic argument for a PST.  For example, expert PST teams allow many procedures that might otherwise go to the OR – to be done in an alternative location.  This almost inevitably saves money and increases satisfaction for patients and providers who are frustrated by access difficulties and complex ‘rules’ (show up two hours early, change into a ‘Johnny’) that accompany a trip to the OR.  Personally, I much appreciate the fact that the author also highlights the idea that the PST can be a real ‘attraction’ for a Children’s Hospital.  As parents and patients become more sophisticated in this area, the provision of expert sedation will be seen as a basic service (like anesthesia for the OR) – not having this available will drive consumers elsewhere. This is the type of service that differentiates the care at a children’s hospital (or any institution) from that provided at other care facilities, not unlike the provision other tertiary or quartinary services such as a PICU service.  If that argument does not resonate with hospital administrators, nothing will.  This article should be Exhibit One when making the case for institutional support to begin or expand a PST.

1. Cravero JP, Blike GT.  Review of Pediatric Sedation.  Anesthesia &  Analgesia.  99:1355-1364, 2004.

Gravenstein D, Berkenstadt H, Ziv A, Shavit I, Keidan I, Sidi A. Supplemental oxygen compromises the use of pulse oximetry for detection of apnea and hypoventilation during sedation in simulated pediatric patients. Pediatrics. 2008 Aug;122(2):293-8

Abstract Excerpted: The goal was to assess the time to recognition of apnea in a simulated pediatric sedation scenario, with and without supplemental oxygen. Methods: A pediatric human patient simulator mannequin was used to simulate apnea in a 6-year-old patient who received sedation for resetting of a fractured leg. Thirty pediatricians participating in a credentialing course for sedation were randomly assigned to 2 groups. Those in group 1 (N = 15) used supplemental oxygen, and those in group 2 (N = 15) did not use supplemental oxygen. A third group (N = 10), consisting of anesthesiology residents (postgraduate years 2 and 3 equivalent), performed the scenario with oxygen supplementation, to ensure validity and reliability of the simulation. The time interval from simulated apnea to bag-mask ventilation was recorded. Oxygen saturation and Paco(2) values were recorded. All recorded variables and measurements were compared between the groups. Results: The time interval for bag-mask ventilation to occur in group 1 (oxygen supplementation) was significantly longer than that in group 2 (without oxygen supplementation) (173 +/- 130 and 83 +/- 42 seconds, respectively). The time interval for bag-mask ventilation to occur was shorter in group 3 (anesthesiology residents) (24 +/- 6 seconds). Paco(2) reached a higher level in group 1 (75 +/- 26 mmHg), compared with groups 2 and 3 (48 +/- 10 and 42 +/- 3 mmHg, respectively). There was no significant difference between the groups in oxygen saturation values at the time of clinical detection of apnea (93 +/- 5%, 88 +/- 5%, and 94 +/- 7%, respectively). Conclusions: Hypoventilation and apnea are detected more quickly when patients undergoing sedation breathe only air. Supplemental oxygen not only does not prevent oxygen desaturation but also delays the recognition of apnea.

Comment:  This paper represents a nice use of simulation to prove a point that has been widely known and discussed in the last several years.  In short, oxygen therapy causes a longer interval between apnea and oxygen desaturation.  The logic follows that this longer interval could result in a longer interval to recognize apnea, and thus, a longer time to respond to apnea (since apnea is not noticed and probably not thought to be as urgent a problem) because of this. The authors do a nice job of describing some of the physiology behind this clinical observation in the discussion section of this paper.  The paper does bring up some obvious points for discussion that need to be appreciated:

1. To accept the conclusions of this study, it must be assumed that performance on a simulator in this setting is representative of performance on actual patients.  Although some work in validating simulation has been completed, there is really very little information that would indicate that we can assume that findings on the simulator translate to real life performance in pediatric sedation. If we are depending on observation of chest wall motion to appreciate apnea, it should be understood that chest wall motion is not perfectly replicated in a simulator – and at times can be somewhat subtle. In addition, we would question whether or not the physiology built into the METI simulator is absolutely representative of pediatric physiology – this has not been proven or validated to our knowledge.  So, question number one: Are the results representative of actual practice? We are not sure.
2. There was no End Tidal CO2 (ETCO2) monitoring included in the study.  This, in spite of the fact that, according to the current AAP Guidelines, ETCO2 should be considered for deep sedation. It is a standard monitor for anesthesiology providers in the operating room environment and for off-site anesthesia provision. We would hazard a guess that most sedation services in the United States make use of ETCO2, as this monitor is well accepted as a valuable adjunct to sedation monitoring. At this point many handheld ETCO2/SpO2 monitors are available at reasonable cost and continuous O2 sampling can be obtained while using nasal cannula or mask O2. Clearly, if ETCO2 is being monitored, it should be a considerable lead monitor for apnea over pulse oximetry.  While the monitor usually does not provide accurate assessments of PaCO2, it can be a very reliable indicator of apnea. So we must ask, "Why not include ETCO2 in this study?" "Is this study relevant for most sedation providers since no ETCO2 monitoring was used?"   Perhaps a more interesting investigation (or follow up investigation) would ask the question –“Is there any difference in time to react to apnea between patients receiving or not receiving O2 when ETCO2 is utilized”. When using ETCO2, a potent argument could be made to add O2 therapy since it would give more time to manage apnea prior to desaturation once it is noticed.
3. Reading the methods section, it appears this study was performed prior to sedation training for the providers involved in the comparison. Once again, it would be important to understand whether or not the differences in recognition of apnea would hold up if all of the providers had more familiarity with the simulators and more training in ventilation monitoring.
4. In an era that emphasizes 'outcomes', we must ask the question as to whether or not there are any clinical implications of a longer interval to recognize and treat apnea. Is there any harm to this longer interval?  Is it a marker of potentially dangerous care?  In general, we would absolutely agree that (on face value) it is better to recognize apnea sooner rather than later.  On the other hand, it is not absolutely the case that just because you can measure a difference in care, it indicates a safety issue or injury to patients.  We must point out that the difference in time to notice apnea is highly dependent on the physiology built into the METI simulator, which, as mentioned above, is not validated. In order to answer the question as to whether or not the differences noted in this study have clinical significance, we would require large demographic studies involving sedation care that are simply not available.  The assumption of this study would be that the difference in time to recognize apnea is important – we feel it is necessary to call the question as to whether this is absolutely the case – or not?

We would conclude that the authors have helped to prove a point that has been long accepted, but we would point out that there are some remaining questions – not the least of which would be “why use a measure of oxygenation to monitor ventilation?”

Please send your comments and questions to the Editor, Joseph Cravero, MD.

Editors:
Joseph Cravero MD
George Blike MD

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

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