A comparison of conventional versus electronicmonitoring of sedated pediatric dental patientsRobin J.R. Croswell, DDS, MS Diane C. Dilley, DDSWarner J. Lucas, DDS, MD William F. Vann Jr, DMD, MS, PhD

AbstractThe first purpose of this study was to compare tradi-

tional monitoring methods to electronic instruments formonitoring physiologic parameters during conscious se-dation of pediatric dental patients. Traditional methodsincluded careful visual assessment of skin color, airwaypatency and chest movements, and auscultation of breathand heart sounds using a precordial stethoscope; electronicinstruments included the capnograph and pulse oximeter.The second purpose of the study was to examine the po-tential of the capnograph to provide more advanced warn-ing than the pulse oximeter for respiratory compromise.

Thirty-nine children (mean age 39 months) received oral sedative regimen of chloral hydrate, hydroxyzinepamoate, and meperidine and all were supplemented with100% oxygen via nasal cannula throughout their seda-tions. One investigator used traditional monitoring andthe other used electronic-- both monitored simultaneouslywhile being shielded (blinded) from each other.

Electronic monitoring yielded a false alert rate of 88%compared with 73% for traditional monitoring. Ten con-firmed episodes of respiratory compromise were identifiedelectronically and only three were identified by traditionalmonitoring. All of the 10 confirmed respiratory compro-mise episodes were detected by capnography; none weredetected by oximetry. During these 39 pediatric sedationsusing a narcotic drug regimen and 100% oxygen supple-mentation, there were no true desaturations. (Pediatr Dent17:332-39, 1995)

T raditional methods of physiologic monitoring ofconsciously sedated pediatric patients includevisual observation of tissue color, measurement

of pulse and respiratory rates and use of a precordialstethoscope for auscultation of heart and breathsounds.1 For electronic monitoring, the pulse oximeterprovides noninvasive monitoring of arterial oxyhemo-globin saturation (SpO2), pulse rate and pulse strength;the capnograph provides noninvasive, quantitativemonitoring of respired carbon dioxide (CO2) tension

and respiratory rate. Pulse oximetry has become a com-mon addition to the monitoring armamentarium forpediatric dental sedation and is required by the 1992guidelines developed by the American Academy ofPediatrics to meet the standard of care for the monitor-ing of sedated pediatric patients.2-11,12 Capnography,however, has had little attention as a monitor for se-dated pediatric dental patients.6.13

The global purpose of this study was to compareinformation derived from traditional monitoring ofsedated pediatric dental patients with information de-rived from the pulse oximeter and the capnograph.

Literature reviewTraditional monitoring methods

The time-honored methods of monitoring sedatedpatients include visual assessment of chest movementsand tissue color, measurement of pulse and respirationrates, and auscultation of heart and breath sounds witha precordial stethoscope. Each of these methods hasbeen shown to have major shortcomings.4,14-18 Visualobservation of the rise and fall of the chest is an impor-tant monitoring procedure, but reveals only respiratoryeffort, not necessarily gas exchange26 During pediat-ric dental sedations, visual observation of tissue colorcan be obscured by dental paraphernalia, such as therubber dam, patient eye protection, and patient re-straints. Furthermore, relying on these clinical signsand symptoms to recognize hypoxemia is unsafe be-cause changes occur late in relation to oxygen satura-tion14 and can be affected by hemoglobin concentration,tissue pigmentation, ambient light, and the observer’sskill in distinguishing color changes.19

The precordial stethoscope provides a simple and.inexpensive extension of the anesthesiologist’s senses,2°

but the design of the instrument (i.e. variation in sizeof the stethoscope, type and length of tubing) can givevarying and unreliable results27 The only accurate in-formation obtainable from the precordial stethoscopeis the presence and characteristics of heart and breathsounds.17 Furthermore, auscultatory assessment can be

332 American Academy of Pediatric Dentistry Pediatric Dentistry - 17:5, 1995

difficult for the practitioner because of noise in theoperatory, such as crying or whining, handpiecesounds, high-speed evacuation, and dental team com-munication.4 Finally, the precordial stethoscope offersunreliable information regarding ventilation adequacy.

Pulse oximetryEarly studies of electronic monitors in the pediatric

sedation environment demonstrated that the pulseoximeter detected incidents of peripheral oxygendesaturations during sedations that did not correspondto irregularities of other physiologic parameters likeblood pressure and pulse rate.2,21,~ This confirmed thatelectronic monitors had the potential to detect mildhypoxemic episodes undetected by traditional means.Since 1985, at least 18 other studies have examinedphysiologic monitoring in the pediatric dental sedationarena.S, 6, 9.10.18, ~6 These studies touted pulse oximetry

as the gold standard for monitors because of its abilityto detect hypoxemia early in the course of a respiratorycompromise in a sedated child.

Although its value has been demonstrated repeat-edly, pulse oximetry is not without limitations. Arti-facts or errors in pulse oximetry output can be intro-duced by hypothermia, altered hemoglobin status,poor tissue perfusion, crying, and patient movement.1°

Pulse oximetry provides a spectrophotometric analy-sis of hemoglobin (i.e., the redness of the blood) and most cases, provides an accurate and reliable measureof the oxyhemoglobin saturation in the central arterialblood;29, 37 however, pulse oximetry will not detect ane-mic, toxic, or ischemic hypoxia because the redness ofthe blood is not altered in these conditions.9

Although the accuracy of the pulse oximeter hasbeen reported to be relatively acceptable in the SpO2range of 70-100%, readings below this range can bedrastically inaccurate due to the shape of the oxyhemo-globin dissociation curve and inherent instrument limi-tations.7, 9, 38 Also, while pulse oximetry gives an accu-

rate reflection of respiratory status, it is not a real-timemonitor of respiratory parameters. For example, in achild with an undetected airway occlusion, the pulseoximeter may not reveal a change for a minute or more,at a point where the partial pressure of arterial oxygen(PaO2) has dropped precipitously. Furthermore, smallchanges in arterial oxyhemoglobin saturation (SaO2)signal large changes in PaO2; accordingly, those whoutilize pulse oximetry must understand the oxyhemo-globin dissociation curve and the basic mechanismsunderlying pulse oximetry and its function as a respi-ratory monitor.

CapnographyCapnography is a technology that relies on monitor-

ing expired concentrations of CO2 using infrared spec-trophotometry. Through a nasal cannula, expired air issampled and analyzed for CO2 by infrared absorption.This technology has proven to be a valid and reliablemethod of monitoring respiratory compromise.4,~,9,18,3~1

Capnography is used easily for children asleep un-der general anesthesia, but this technology has practi-cal limitations for consciously sedated children includ-ing nasal cannula displacement during head movementand cannula obstruction with nasal secretions.39, 41.42Mouth breathing also may reduce the accurate detec-tion of expired air. 4~ However, a major advantage ofcapnography is its potential to detect an airway com-promise before it can lead to a change in hemoglobinsaturation.6,10, 4o

Few studies have examined the use of capnographyfor sedated pediatric dental patients. Iwasaki et al.6

demonstrated that the capnograph detected airwayobstruction prior to pulse oximeter detection and founda trend in decreased respirations approximately 30sec prior to a desaturation event. However, underthe conditions of Iwasaki’s study, the capnograph’searly warning did not provide a practical advantageover the pulse oximeter.

Oxygen supplementation

Anesthesiologists suggest oxygen supplementationas one method to improve the safety of conscious seda-tion.s,43,~ In the supplemented patient, there is an extramargin of safety against hypoxemia because the PaO2can be elevated to as high as 600 mm Hg. Due to therelationship of PaO2 to SaO2 on the oxyhemoglobin dis-sociation curve, however, the pulse oximeter does notreveal downward trends in PaO2 at levels greater than100 mm Hg. Thus, in the hyperoxic child, the PaO~ mayneed to fall drastically before any change will be de-tected in the SAO2.5,9 For this reason, in children supple-mented with 100% 02, the capnograph may provide anearlier warning of respiratory problems than the pulseoximeter. To date, this question has not been studied.

Current standard of care for monitoring sedatedpediatric patients

Conscious sedation is defined as a minimally de-pressed level of consciousness wherein a patient retainsthe ability to maintain a patent airway. Deep sedationis defined as a controlled state of depressed conscious-ness or unconsciousness wherein the patient may losethe ability to maintain a patent airway. In the-conven-tional dental office setting, conscious sedation is thedesired level of CNS depression; however, even underconscious sedation, pediatric patients are at risk forrespiratory compromise from a drug-induced respira-tory depression or airway obstruction, which can leadto hypoxemia2~, 35, 36, 45~t9

To promote greater safety in the sedation of pediat-ric dental patients, in 1985 the Guidelines for the ElectiveUse of Conscious Sedation, Deep Sedation, and GeneralAnesthesia in Pediatric Patients specified, at a minimum,the use of a precordial stethoscope for continuous moni-toring of heart rate and respiratory rate, and periodicevaluation of tissue color, nailbed color, and mucosacolor2 In 1992, these guidelines were revised and speci-fied for conscious sedation that heart rate, respiratory

Pediatric Dentistry - 17:5, 1995 American Academy of Pediatric Dentistry 333

rate, blood pressure, and oxygen saturation (SpO2) bemonitored continuously and that monitoring equipmentshould include, at a minimum, a pulse oximeter.12

The guidelines define a standard of care for moni-toring sedated pediatric patients, and although nearly20 studies have been undertaken in the pediatric den-tal environment confirming pulse oximetry’s validity,convenience, and practicality, it is clear that this tech-nology has been embraced slowly. Surveys suggest thatthe use of the pulse oximeter during pediatric sedationsranges from 0 to 69%.5°-52

In spite of a plethora of information on traditionalmonitoring and electronic monitoring, no systematiccomparisons have been reported. Thus, the first objec-tive of this study was to compare systematically threemethods of monitoring physiologic parameters of chil-dren consciously sedated for dental treatment: 1) tra-ditional monitoring using visual observation, measure-ment of heart and respiratory rates, and use of theprecordial stethoscope for auscultation of heart andbreath sounds; 2) pulse oximetry; and 3) capnography.

Our second objective was to examine the addedpotential of the capnograph to provide a more ad-vanced warning than the pulse oximeter for ventilatorychanges in consciously sedated pediatric patients re-ceiving supplemental 100% 02.

Methods and materialsSample

The initial sample consisted of 44 pediatric conscioussedation patients that fulfilled specific criteria. All 1)met Class I ASA anesthesia risk assessment, 2) were 24-48 months old, 3) were referred to the departmentalsedation clinic because of unmanageable behavior inthe conventional dental environment, and 4) had re-storative dental procedures lasting at least 30 min fromtime of local anesthetic injection.

MethodsChildren were referred to the Pediatric Sedation

Clinic (PSC) at the University of North Carolina Chapel Hill School of Dentistry where a preliminaryscreening examination was completed to determinewhether conscious sedation was an appropriate treat-ment option. The PSC’s routine protocol requires: 1) presedation physical from the child’s physician, 2) in-formed consent from the legal guardian for conscioussedation and all needed dental care, and 3) written pre-and postoperative sedation instructions with a parent’sor guardian’s signature confirming their comprehen-sion of these instructions. Specific informed consent alsowas obtained for each child’s participation in this study.

All patients received the standard PSC oral sedationregimen of 50 mg/kg chloral hydrate (PharmaceuticalBasics Inc, Morton Grove, IL), 25 mg hydroxyzinepamoate (Vistaril ®, Pfizer Laboratories, New York, NY),and 1.5 mg/kg meperidine (Demerol®, Winthrop-Breon, New York, NY). No patient received nitrousoxide/oxygen analgesia.

After receiving sedation medications, the patientand parent/guardian waited in a quiet, comfortablepreop sedation room. Forty-five to 60 min after receiv-ing medications, the child was taken to the dentaloperatory, placed in a Papoose Board® (Olympic Medi-cal Group, Seattle, WA), and monitoring probes wereattached. To deliver oxygen and collect expired CO2, anasal cannula (No. 4706F, Salter Labs, Arvin, CA) forcapnography monitoring was placed in the child’snares. The pulse oximeter probe Oxisensor II ® (NellcorInc, Hayward, CA) was placed either on the first orsecond toe of the left foot. Due to possible variationsin pulse oximeter readings caused by skin temperaturechanges, a temperature probe (Hi-Lo Temp Skin®,

Mallinckrodt Medical Inc, Raleigh, NC), using the Mon-a-therm® temperature monitor (Mallinckrodt MedicalInc, Raleigh, NC), was placed on the dorsum of the leftfoot next to the toes. Both feet were covered with atowel to reduce ambient light. A precordial stethoscopewas placed to the left of the sternum for auscultationof breath and heart sounds.

For this study, the Nellcor-1000® (Nellcor Inc,Hayward, CA) electronic monitor was used. This in-strument is a combination pulse oximeter-capnographthat can be connected to a printer to print trend data.

Consistent with the PSC protocol for conscious se-dations of children 24-48 months old, all received 100%02 supplementation, starting immediately upon theirbeing seated in the dental chair. The large tubing con-nector of the cannula system was attached to an oxy-gen outlet and O2 was delivered at a flow rate of 3 L/min through the same cannula used for CO2 sampling.

All patients were monitored simultaneously by twoinvestigators experienced in physiologic monitoring ofsedated children. The investigators were shielded(blinded) from one other, but each had an unobstructedview of the patient and dentist/operator. Heart rate(HR) and respiratory rate (RR) were recorded on sepa-rate standard monitoring records by both investigatorsand synchronized for recording at 5-min intervals. Atany time during treatment, either investigator couldalert the operator when respiratory compromise wassuspected and necessary adjustments (i.e., patient headposition or cannula adjustment) would be made by theoperator. Each investigator recorded their alerts ontheir respective monitoring record. The audio alarmswere silenced to blind Investigator A from the elec-tronic monitors’ audio signals.

Investigator A monitored by continuous visual as-sessment, auscultation with a precordial stethoscope,and palpation for chest movement. Investigator B re-corded data from the Nellcor-1000 monitor, from whichhard copy printouts were generated at the conclusionof each case. Investigator B monitored the electronicpanels continuously, recording patient behavior andthe procedure events simultaneously. With each occur-rence of a desaturation or apneic episode, InvestigatorB used the time-based hard copy printout to make spe-

334 American Academy of Pediatric Dentistry Pediatric Dentistry - 17:5, 1995

cific notes about events occurring at the time (injection,rubber dam placement, crown placement, etc.) andpatient movement. Axial foot temperatures were re-corded every 5 min. To assess the effectiveness of thestandard monitoring techniques, Investigator B alertedthe operator of suspected respiratory compromisewhen the pulse oximeter read less than 90% SpO2 forlonger than 30 sec or when the capnograph showedapnea of longer than 15 sec.

At the conclusion of the sedation appointment, con-sistent with our PSC protocol, the operator and bothinvestigators arrived at a consensus on the sedationoutcome. Each case received a rating of either excellent,satisfactory, unsatisfactory, or aborted (Table 1) accord-ing to established criteria to which both investigatorsand operators were calibrated.

Data analysisTo compare systematically the methods of monitor-

ing physiologic parameters of children consciously se-dated for dental treatment, the data recorded on theanesthesia records for investigators A and B were com-pared with the number of investigator alerts to theoperator during the sedation. Episodes of true respira-tory compromise were defined as abnormalcapnograph readings >15 sec during times of sleep orquiet behavior. Hard data printouts for the pulseoximeter and capnograph were compared also to de-termine whether trends could be found in capnographythat could provide an earlier warning signal than wasdetected with pulse oximetry. The study design andsample size dictated that we rely upon descriptiverather than statistical data analysis.

Results

Forty-four patients (mean age, 39 months; range24-48 months) were enrolled in the study. Five (11%)sedation cases were aborted due to uncooperative be-havior, so data were collected from 39 patients only.Of the 39 completed sedation cases, 13 (30%) were rated

as excellent sedations, 16 (36%) as satisfactory, and (23%) as unsatisfactory. Because patient behavioroften affects monitoring, results were analyzed by be-havioral category.

Traditional versus electronic monitoringComparison of the number of alerts for respiratory

compromise to the operator by Investigator A versusInvestigator B is shown in Table 2. Investigator A gave11 alerts, of which three were confirmed as respiratorycompromise or true positives. Eight of the 11 alertswere associated with normal capnograph readings andwere considered artifacts or false positives associatedwith a displaced precordial stethoscope, or with un-usual airway sounds without obstruction. The overallfalse positive rate was 73% for Investigator A.

Relying upon the electronic monitors, InvestigatorB gave 85 alerts. Ten were confirmed as true respira-tory compromise. Seventy-five were false positives, alloccurring during times of poor patient behavior, opera-tor or patient interference, or mechanical obstructionof the sampling ports. The overall false positive ratewas 88% for Investigator B.

For comparisons by behavior category, InvestigatorA had the lowest overall false positive rate and the low-est rate of 33% for the satisfactory behavior category(Table 2). For all other categories, results for both in-vestigators were nearly identical. However, Investiga-tor B detected seven episodes of clinically confirmedrespiratory compromise that were not detected by In-vestigator A. In summary, the electronic monitors hada higher overall false positive rate but detected moretrue positive (10 versus three episodes).

Pulse oximetry versus capnography

Data from pulse oximetry revealed a total of 16 read-ings of SpO2 < 90% in nine patients. As illustrated inTable 3, all abnormal readings were attributed to pa-tient movement, monitor displacement, or a lowextremity temperature. One patient experienced an8° drop in foot temperature from 95 to 87°F, but for

TABLE . SEDATION OUTCOME RATINGS TABLE2. ALERTS TO OPERATOR

Excellent

Satisfactory

Unsatisfactory

Aborted

Treatment completed without diffi-culty, minimal crying and patient quietand/or asleep for most of case

Treatment completed with minimaldifficulty, but alternating periods ofcrying and struggling with periods ofquiet and/or sleep

Treatment completed with difficultydue to crying and struggling through-out treatment

Treatment not completed due tocombative behavior that increased therisk of injury to the patient or thedental team

Sedation Rating Total True % False %

InvestigatorA

Unsatisfactory 2 0 0 2 100Satisfactory 3 2 67 1 33Excellent 6 1 17 5 83Overall 11 3 27 8 73

Investigator B

Unsatisfactory 25 0 0 25 100Satisfactory 43 7 16 36 84Excellent 17 3 18 14 82Overall 85 10 12 75 88

Pediatric Dentistry - 17:5, 1995 American Academy of Pediatric Dentistry 335

all other patients valuesremained constant with fluc-tuations of no more than 5° Variable(range 87-98 ~F).

An abnormal capnographicreading was defined as a pe-riod of no nasal breathing for aperiod longer than 15 sec. Data Totalanalysis revealed 85 abnormalcapnographic readings in 31patients. As illustrated in Table4, 65 abnormal readings (76%) Variableoccurred during periods ofpoor patient behavior duringcrying and mouth breathing.Ten abnormal readings (12%)occurred with operator or pa-tient interference of the nasalcannula. Ten abnormal read-ings (12%) occurred when the Totalpatients were quiet or asleepand were confirmed clinically

TABLE3. ABNORMAL PULSE OXIMETER READINGS

Incfdence

Monitor displacement 8 50Struggling 4 25Low foot temperature 4 25

16

TABLE4. ABNORMAL CAPNOGRAPH READINGS

Incidence

Poor patient behavior 65(crying, mouth breathing)

Operator/patient interference 10(cannula displacement)

Patient asleep 10

100

as true episodes of respiratory compromise with no evi-dence of airway exchange. In each case, normal respi-ratory pattern was established with correction of headposition. Recovery time from a confirmed respiratorycompromise was on average 33 sec (range 15-72 sec).There were no desaturations during any of these casesof true respiratory compromise.

DiscussionThe need to monitor

Morbidity and mortality statistics from sedationsand general anesthesia cases in dental offices revealthat most misadventures in the dental environmentresult from shortcomings in patient management, spe-cifically the underuse of monitoring and resuscitativeefforts.53, s4 In a review of mishaps in the dental office,Krippaehne53 reported that 62% of the patients weremonitored by visual observation only, and routinephysiologic monitoring was uncommon. Severalstudies have surveyed the monitoring methods usedspecifically for pediatric conscious sedations. Findingssuggest that practitioners recognize the need tomonitor pediatric patients cautiously, but mostdon’t use the most effective monitoring methods intheir daily practice.5°-5z 55, 56

The 1985 Sedation Guidelines1 were the first estab-lished standards of care for the pediatric ~edationarena. Recent surveys5°-52, 5s, 56 reveal disappointingcompliance with these guidelines in daily practice. Asone example, a 1992 survey of physicians who sedatedchildren for diagnostic procedures revealed that mostwere unaware of the guidelines and only 18% thoughtthey applied to their procedures.52

Factors limiting usefulness of monitoring methodsWe found that traditional monitoring methods are

comparable to electronic monitoring when patients are

76

12

12

85 100

well-sedated, but precordialstethoscope monitoring is af-fected strongly by crying androom noise. In particular, respi-ratory rate is difficult to assesswith a precordial stethoscopebecause of crying or room noise,forcing reliance upon visual ob-servation and/or palpation ofchest movement.

Relative to false alerts, thetraditional monitoring methodsmay have more discriminationduring the unsatisfactory andsatisfactory sedations but lesssensitivity during those caseswhen the patient is well-sedated(Table 2). Our results show thattraditional monitoring methodsmissed episodes of true respira-tory compromise that the elec-tronic monitoring detected.

Concurring with the findings of Anderson et alo5 andIwasaki et al., 6 we found that electronic monitors be-came more valuable with increasing depths of sedation.As have other investigators,7, 57-61 we found that oftenthe pulse oximeter gives false readings secondary tomotion artifact during struggling, muscle tension of theextremity, monitor displacement, low extremity tem-perature, ambient light, and incorrect probe placement.Like Pan et al., 62 we found that most pulse oximeterfalse alarms are due to motion.

The accuracy of capnography can be affected by cry-ing, struggling, nasal congestion, and mouth breathing,all of which can be identified incorrectly as an apparentapneic episode. With capnography we experienced anoverall false positive rate of 88% for warnings. Despiteits false positives, the capnograph was the best methodto detect airway compromise, especially during peri-ods of greater depths of sedation, sleep, or quiet.

It seems clear that the clinical adjustments made forabnormal capnographic readings almost certainly pre-vented potential desaturations from occurring. It isimpossible to know from our study design whether thepulse oximeter, if given more time, would have de-tected a respiratory compromise. Based on these re-sults, the capnograph provided, at a minimum, a 15-sec advance warning for a potential desaturation.Under the conditions of this study, it was not possibleto determine if these episodes would have been self-limiting or would have gone on to cause physiologicharm to the patient if not corrected.

We found that patient behavior influenced the effec-tiveness of the different monitoring methods. For thechild who is sedated well from the appointment’s startto finish, all monitoring methods can be equally effec-tive. However, we have found that the sedatedchildren’s behavior was quite variable, sometimes

336 American Academy of Pediatric Dentistry Pediatric Dentistry - 17:5, 1995

;hanging mh~ute-to~minute within the same appoint-ment. These results show that all monitoring methodsgive false positive warnings, but for the child who iswell-sedated, capnography proved to be more effectivein detecting a true respiratory compromise.

Capnography is an excellent method for detectingdecreased respiratory rate or apnea, but it does notprovide quantitative assessment of minute ventilation.Therefore, it should be used as an adjunct to traditionalmonitoring methods. Even though we detected no truedesaturations, the pulse oximeter provides confirma-tion that a patient’s respiratory efforts are providingadequate blood oxygenation.

Pediatric sedations with supplemental oxygen

Evidence is overwhelming that hypoxemia is themajor risk factor in pediatric sedation2,4~ In healthy,sedated pediatric patients, hypoxemia can result from1) a drug-induced respiratory depression from a de-creased rate or depth of respiration or 2) airway ob-struction due to loss of protective reflexes secondaryto the sedative drug effect.

Children have a high basal oxygen consumption andtheir smaller size provides less oxygen reserve, Becauseof the risk of hypoxemia during conscious sedation,supplementation has been recommended to provide anOa reserve to give an extra measure of protection forsedated patients.4~, ~A, ~ Because supplemental O~creases pulmonary O~ reserve capacity, desaturation ofhemoglobin is delayed during periods ofhypoventilation. In a normally ventilating patient re-ceiving supplemental O~,, the PaO~ may increase from90 to 100 mm Hg on room air to as high as 600 mm Hg,depending upon the actual inspired O~ concentration.Due to the increased pulmonary O~ reserve and subse-quent increased arterial O~ content, patients gain pro-tection during periods of hypoventilation. Because ofthe nonlinear shape of the oxyhemoglobin dissociationcurve, decreasing levels of arterial O~ content will notbe detected by the pulse oximeter until hemoglobinsaturation begins to change to a PaO~ of < I00 mm Hg.

it should be noted that if a child hypoventilates dur-ing Oz supplementation, it is possible that arterial CO~can rise, A significant rise could lead to respiratoryacidosis. While the relative risk of respiratory acidosisis less than that of hypoxemia, it should be noted thatO~ supplementation can mask hypoventilation andhypercarbia. We concur with Phero~ that thecapnograph provides an extra measure of safety be-cause it monitors for hypoventilation and hypercarbia,but the absence of a capnograph should not dissuadethe practitioner from utilizing O~ supplementation inhealthy sedated children.

We found that capnography gives immediate detec-tion of airway compromise prior to any potentialdesaturation events, supporting findings by Andersonet aL~ and Iwasaki et aI.~ In contrast to our patients,Iwasaki’s were not supplemented with O~ but

desaturations were reported in that study on childrenof similar ages as those in our study.

In our study using an oral narcotic regimen and100% O~ supplementation via nasal cannula, no truedesaturations were found in 39 conscious sedations.A s~udy by Roberts et al. reported no desaturations in42 narcotic sedations in children supplemented withnitrous and oxygen analgesia.6~ Taken together, thesestudies suggest when sedated children are supple-mented with Oa and when airway compromise isdetected quickly and corrected, there is little chanceof desaturation episodes as detected by pulse oximetry,We would caution, however, that our study examinedsupplementation via 100% O~, not via nitrous oxideand oxygen analgesia, Others have suggested that thesedative effects of nitrous oxide may counterbalance the effects of the O~. supplementation innitrous oxide and oxygen analgesia,ss so this questionneeds further study,

ConclusionsUnder the conditions of this investigation:

1, Electronic monitoring identified 10 episodes ofconfirmed respiratory compromise, of whichonly three were identified using traditio~_al moni-toring. Therefore, for maximum patient safety,electronic monitoring should be used in additionto traditional methods to monitor sedated pedi~atric dental patients.

2. Traditional monitoring had a false positive rateof 73 versus 88% for electronic monitoring; how-ever, the overall clinical impact of providing amore sensitive method of detecting potentiallyharmful episodes of respiratory compromise faroutweighs any relative inconvenience caused byfalse positives.

3. There were 10 confirmed episodes of respiratorycompromise detected by capnography and noneof the 10 were detected by pulse oximetry,

4. No true desaturations occurred during 39 seda-tions using an oral narcotic drug regimen and100% O~ supplementation.

Dr. Croswell was a fellow (at time of study)~ Department of Pedi-atric Dentistry, School of Dentistry; Dr. Dilley is an associate pro-fessor, Department of Pediatric Dentistry, School of Dentistry; Dr.Lucas is an associate professor, Department of Anesthesiology,School of Medicine; Dr. Vann is a professor and graduate programdirector, Department of Pediatric Dentistry, School of Dentistry,all University of North Carolina at Chapel

This work was supported by a grant from the USPHS Bureau ofMaternal and Child Health (#MCJ-379494), which supports a Pe~diatric Dental Training Center at the University of North Carolinaat Chapel Hill, NC.

Special thanks is given to Nellcor, Inc. for consignment of theb~ation pulse oximeter/capnograph instrument used in this study.

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25. Moody EH, Mourino AP, Campbell RL: The therapeutic ef-fectiveness of nitrous oxide and chloral hydrate adminis-tered orally, rectally, and combined with hydroxyzine forpediatric dentistry. ASDC J Dent Child 53:425-29, 1986.

26. Eichhorn JH, Cooper JB, Cullen DJ, Maier WR, Philip JH,Seeman RC: Standards for patient monitoring during anes-thesia at Harvard Medical School. JAMA 256:1017-20,1986.

27. Lambert LA, Nazif MM, Moore PA, Zullo TG: Nonlineardose-response characteristics of alphaprodine sedation inpreschool children. Pediatr Dent 10:30-33, 1988.

28. Currie WR, Biery KA, Campbell RL, Mourino AP: Narcoticsedation: an evaluation of cardiopulmonary parameters andbehavior modification in pediatric dental patients. J Pedod12:230-49, 1988.

29. Anderson JA, Lambert DM, Kafer ER, Dolan P: Pulseoximetry: evaluation of accuracy during outpatient generalanesthesia for oral surgery: a comparison of four monitors.Anesth Prog 35:53-60, 1988.

30. Poorman TL, Farrington FH, Mourino AP: Comparison ofa chloral hydrate/hydroxyzine combination with and with-out meperidine in the sedation of pediatric dental patients.Pediatr Dent 12:288-91, 1990.

31. Meyer ML, Mourino AP, Farrington FH: Comparison oftriazolam to a chloral hydrate/hydroxyzine combination inthe sedation of pediatric dental patients. Pediatr Dent12:283-87, 1990.

32. McKee KC, Nazif MM, Jackson DL, Barnhart DC, Close J,Moore PA: Dose-responsive characteristics of meperidinesedation in preschool children. Pediatr Dent 12:222-27,1990.

33. Wilson S, Tafaro ST, Vieth RF: Electromyography: its poten-tial as an adjunct to other monitored parameters duringconscious sedation in children receiving dental treatment.Anesth Prog 37:11-15, 1990.

34. Badalaty MM, Houpt MI, Koenigsberg SR, Maxwell KC,Desjardins PJ: A comparison of chloral hydrate anddiazepam sedation in young children. Pediatr Dent 12:33-37, 1990.

35. Hasty MF, Vann WF Jr, Dilley DC, Anderson JA: Conscioussedation of pediatric dental patients: an investigation ofchloral hydrate, hydroxyzine pamoate, and meperidine vs.chloral hydrate and hydroxyzine pamoate. Pediatr Dent13:10-19, 1991.

36. Sams DR, Russell CM: Physiologic response and adverse re-actions in pediatric dental patients sedated withpromethazine and chloral hydrate or meperidine. PediatrDent 15:422-24, 1993.

37. Aughey K, Hess D, Eitel D, Bleecher K, Cooley M, OgdenC, Sabulsky N: An evaluation of pulse oximetry inprehospital care. Ann Emerg Med 20:887-91, 1991.

38. Webb RK, Ralston AC, Runciman WB: Potential errors inpulse oximetry. II: Effects of changes in saturation and sig-nal quality. Anaesthesia 46:207-12, 1991.

39. Ackerman WE, Phero JC, Reaume D: End tidal carbon dioxideand respiratory rate measurement during conscious sedationthrough a nasal cannula. Anesth Prog 37:199-200, 1990.

40. Wright SW: Conscious sedation in the emergency depart-ment: the value of capnography and pulse oximetry. AnnEmerg Med 21:551-55, 1992.

41. Prstojevich SJ, Sabol SR, Goldwasser MS, Johnson C: Util-ity of capnography in predicting venous carbon dioxide par-tial pressure in sedated patients during outpatient oral sur-gery. J Oral Maxillofac Surg 50:37-40, 1992.

42. Phero JC: Pharmacologic management of pain, anxiety, andbehavior: conscious sedation, deep sedation, and generalanesthesia. Pediatr Dent 15:429-34, 1993.

43. Papageorge MB, Hunter MJ, Norris LH, Rosenberg MB:Supplemental oxygen after outpatient oral and moxillofacialsurgery. Anesth Prog 39:24-27, 1992.

44. Allen GD: Diagnosis and treatment of respiratory problemsin sedation and anesthesia for dentistry. Anesth Prog39:150-56, 1992.

45. Goodson JM, Moore PA: Life-threatening reactions afterpedodontic sedation: an assessment of narcotic, local anes-thetic, and antiemetic drug interactions. J Amer Dent Assoc107:239-45, 1983.

338 American Academy of Pediatric Dentistry Pediatric Dentistry - 17:5, 1995

46. Moore PA: Local anesthesia and narcotic drug interactionin pediatric dentistry. Anesth Prog 35:17, 1988.

47. Decker DE: The respiratory effects of drugs used for con-scious sedation and general anesthesia. J Am Dent Assoc119:153-56,1989.

48. Becker DE: Letters to the editor-author's comment. J AmDent Assoc 119:474-75,1989.

49. Needleman HL: Conscious sedation for pediatric outpatientdental procedures. Int Anesthesiol Clin 27:102-8,1989.

50. Houpt M: Project USAP the use of sedative agents in pedi-atric dentistry: 1991 update. Pediatr Dent 15:36-40, 1993.

51. Dilley DC, Fields HW Jr: The practice of pediatric dentistry:specialty versus general practice. Pediatr Dent 13:393,1991.

52. Cook BA, Bass JW, Nomizu S, Alexander ME: Sedation ofchildren for technical procedures: current standard of prac-tice. Clin Pediatr (Phila) 31:137-42, 1992.

53. Krippaehne JA, Montgomery MT: Morbidity and mortalityfrom pharmacosedation and general anesthesia in the den-tal office. J Oral Maxillofac Surg 50:691-99,1992.

54. Jastak JT: Morbidity and mortality from pharmacosedationand general anesthesia in the dental office. J Oral MaxillofacSurg 50:698-99,1992.

55. Wilson S, McTigue DJ: Survey of conscious sedation prac-tices in pediatric dentistry advanced residency programs. JDent Ed 53:595-97,1989.

56. Keeffe EB, O'Connor KW: 1989 A/S /G/E survey of

endoscopic sedation and monitoring practices. GastrointestEndosc 36(3):S13-18,1990.

57. Southall DP, Samuels M: Inappropriate sensor applicationin pulse oximetry [letter]. Lancet 340:481-82, 1992.

58. Verwest TM, Primosch RE, Courts FJ: Variables influencinghemoglobin oxygen desaturation in children during routinerestorative dentistry. Pediatr Dent 15:25-29,1993.

59. Norton LH, Squires B, Craig NP, McLeary G, McGrath P,Norton KI: Accuracy of pulse oximetry during exercisestress testing. Int J Sports Med 13:523-27, 1992.

60. Ralston AC, Webb RK, Runciman WB: Potential errors inpulse oximetry. I: Pulse oximeter evaluation. Anaesthesia46:202-6,1991.

61. Ralston AC, Webb RK, Runciman WB: Potential errors inpulse oximetry. Ill: Effects of interferences, dyes,dyshaemoglobins and other pigments. Anaesthesia 46:291-95,1991.

62. Pan PH, James CF: Effects of default alarm limit settings onalarm distribution in telemetric pulse oximetry network inward setting. Anesthesiology 75:A405,1991.

63. Anderson JA, Tucker MR: Letters to the editor. JADA119:474,1989.

64. Roberts SM, Wilson CFG, Seale NS, McWhorter AG: Evalu-ation of morphine as compared to meperidine when admin-istered to the moderately anxious pediatric dental patient.Pediatr Dent 14:306-13,1992.

Newly Elected Officers of the American BoardDr. Elizabeth S. Barr, West-

minster, Colorado, was recentlyelected Chair of the AmericanBoard of Pediatric Dentistry afterserving as a Director of the Boardsince 1989. Dr. Barr received herdental degree and specialty train-ing in pediatric dentistry from theUniversity of Kentucky College ofDentistry, and she is a Fellow of

Elizabeth S. Barr tne American College of Dentists.Dr. Barr has served on the American Academy of Pe-diatric Dentistry's Public Information Committee, andshe has been active in the Annual Meeting Program bypresenting mini-clinics, research papers, and panel dis-cussions. She is a Past President of the Colorado Unitof the American Society of Dentistry for Children.

Dr. Paul O. Walker, Associate Dean for ClinicalAffairs at Baylor College of Dentistry, was elected tothe position of Director of the American Board ofPediatric Dentistry during the Annual Meeting of theAmerican Academy of Pediatric Dentistry in San Fran-

Paul O. Walker

cisco, California. Dr. Walker alsois a Professor in the Departmentof Pediatric Dentistry at BaylorCollege of Dentistry and a Diplo-mate of the American Board ofPediatric Dentistry. He is an ac-tive member of the following pro-fessional organizat ions; theAmerican Academy of PediatricDentistry, American Associationof Dental Schools, Texas Acad-

emy of Pediatric Dentistry, American Dental Asso-ciation, Texas Dental Association, and Dallas CountyDental Society. In addition, Dr. Walker is on the staffof Texas Scottish Rite Hospital, Children's MedicalCenter of Dallas, and Baylor University Medical Cen-ter. Dr. Walker received a DDS from NorthwesternUniversity and an MS from Indiana University. Hewas a member of the faculty at the University ofMinnesota from 1972 until 1994. Dr. Walker and hiswife, Jill Stoltenberg, have residences in both Dallas,Texas, and Shoreview, Minnesota.

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