Introduction Adriani defines monitoring thusly-"The term monitoring refers to the overall surveillance of the patient by methods employing the senses of touch, sight, hearing or smell or by means of devices which operate chemically, physically or electronically to measure the adequacy of the various physiological functions."' During the past 25 years in dentistry, preoperative and intraoperative monitoring has progressed from near ground zero to the present stage of adequacy and even sophistication. These changes have come about for five reasons: 1. Normal elevation of standards in the public good. 2. The vast increase of pain/anxiety control modalities in recent years, particularly conscious-patient sedation. 3. The vastly increasing numbers of geriatric patients seeking dental care. These potentially fragile patients now number 10.3 percent of the general population (up from 9.2 percent in 1960). Now utilizing 30 percent of the nation's health resources, it is projected that people over 65 will number 30 million by the year 2000. 4. The introduction of external cardiopulmonary resuscitation in the early 1960's, thus no longer categorizing sudden death in the dental office as an untreatable statistical observation, but demanding immediate reversal of that death if possible. 5. Vastly increasing professional negligence claims, particularly wrongful death suits. I have been happily involved in various modalities of pain/anxiety control for the past 25 years of my professional life. It 'Professor and Chairman, Section of Anesthesia and Medicine, University of Southern California School of Dentistry. Presented at the annual scientific session of the American Dental Society of Anesthesiology, February 20, 1977, Chicago.


is reasonable to think that I might have learned something in that 25 years, and that I might even be able to pass along some useful information. For the purposes of this paper I could adopt the attitude of a militant reactionary and condemn sophisticated (i.e., "complicated") monitoring. Sam Goldwyn's classic position could be taken, and I could say, "My mind is nade up. Don't bother me with the facts." Or my position could be that of unbridled enthusiasm for sophisticated monitoringfour-square for electrocardioscopes, capnographs, oximeters, precordial heart sounds, continuous blood pressure monitoring, electric thermometers, and any other equipment that automatically records, bleeps, flashes, or hums. But the more I learn and experience in this wonderful world of pain/anxiety control, the more I realize that I don't know a great deal. Let us explore the past and present of monitoring in dentistry, and even try to take a look into the future. Let us see if our experience points the way to guidelines to better and safer pain/anxiety control for our patients. The Past Shortly after the turn of the century, nitrous oxide-oxygen enjoyed a considerable burst of popularity for both consciouspatient sedation and for general anesthesia. While the sedation was called analgesia, and failed for that very reason, because too much was expected of it, the use of nitrous oxide as a general anesthetic agent continued to enjoy great popularity. This despite the fact that nitrous oxide is a very weak anesthetic agent. Yet it was the only agent the dental practitioner had at the time by which he could offer pain/ anxiety control for frightened patients. The gas men were giants. They understood nitrous oxide as we never will. They took a weak anesthetic agent and adapted to it by operating with extreme speed and efficiency. They originated the anesthesia team, which we have recently rediscovered, each member highly trained to perform 33

at peak efficiency during a very short and exciting anesthetic. My father was a gas man, a member of this legendary breed, utilizing nitrous oxide-oxygen anesthesia since 1918, 59 years ago. He used the early models of the demand-flow Heidbrink and McKesson machines, his last machine being a Heidbrink Simplex which he was unable to have repaired three years ago, thus ending the saga. He administered 60,000 nitrous oxide-oxygen general anesthetics during that 56-year period without a fatality. As far as I have been able to determine from the fragmentary available statistics, the mortality rate of the gas men approximated the mortality rate which we point to with pride today, which is food for thought. Was it because of the extremely short anesthetic durations-that is, the fact that the dominoes did not have time to fall? As a child in the 1930's, I was privileged to witness out-patient nitrous oxide-oxygen anesthesia many times, and the usual preoperative and intraoperative monitoring that accompanied the technique. I have seen full-mouth extractions accomplished in 3-5 minutes. I have seen patients get black and then black again, restraints straps break like thread, instrument trays kicked out of opened and unopened windows, assistants hanging on the patient's flailing arms and lega, assistants sitting in the lap of struggling patients, and patients on the floor struggling with assistants and doctor. The gas men were iron men. They had to be. One might be tempted to say that monitoring did not exist in the early 1900's. Perhaps by today's standards it did not, but by the standards of that day it surely did. Physical evaluation and the preoperative determination of vital signs was virtually unknown. Preoperative preparation of the patient usually was limited to three areas: 1. The question, "Are you in good health," comprising the medical history, followed by a brief dialogue history as indicated, and to the best of the practitioner's ability. 2. Inspection of the patient, much as we do today, concerning physical distress, dyspnea, wheezing expirations, 34

ankle edema, and the smell of alcohol. Those practitioners could pick out an alcoholic at 15 feet, a case to be avoided. 3. Most of those practitioners were located in second floor offices not served by an elevator. If the patient could climb a flight of stairs without unusual fatigue or dyspnea upon presenting at the office, he was considered to be a good risk. Dental practitioners of that era using nitrous oxide-oxygen also performed intraoperative monitoring. They observed respirations, color of the skin and mucous membranes, eye signs, and extremity movement. Postoperative monitoring was unknown. The Present Beginning in the late 1930's and early 1940's, an ultrashort acting barbiturate, thiopental sodium, was introduced. This allowed longer anesthetic duration and the performance of well executed, not frantic, dentoalveolar surgery and occasionally restorative dentistry. Preoperative monitoring kept pace with this new era, and a routine dialogue medical history consisting of 4-5 questions became a standard in most offices using intravenous anesthesia of that day. Determination of preoperative blood pressure became routine in many offices using general anesthesia, but was still a rarity in most general dental offices. At about this same time in the 1940's dental schools began adopting a written medical history, patient-completed for the most part, which has expanded to a comprehensive health analysis similar to the ADA long-form medical history today.6 Schools have been adding vital signs to the initial physical evaluation, and some now routinely measure blood pressure, pulse rate, respiratory rate, temperature, height, and weight. A few schools also monitor the following clinical laboratory parameters during the initial physical evaluation: blood-hematocrit and hemoglobin; urine-albumin, glucose, acetone, and micro. Certain schools are also offering health and psychosocial referral services as indicated, in addition to comprehensive health screening. This marks the beginning, in ANESTHESIA PROGRESS

my opinion, of a valuable public health service which will be offered in the near future by increasing numbers of general dental practitioners-that is, first contact medicine via comprehensive health screening, counseling on general health and diet in addition to preventive dentistry, and referral to secondary health care facilities as indicated. Thus is dentistry assuming a more important role as a member of the interdisciplinary health team. During the period since the 1950's as intravenous anesthesia became more sohisticated and was joined by new inhalation agents, preoperative monitoring became more comprehensive in the private office. The brief dialogue history was supplanted for the most part by a patient-completed medical history similar to the ADA shortform medical history.6 Preoperative determination of vital signs, in addition to blood pressure, increased in offices using general anesthesia, until at the present time pulse rate, respiratory rate, and temperature are common, with some offices adding height, weight, and some or all of the clinical laboratory tests listed previously. During the past 15 years a quantum leap in preoperative and intraoperative monitoring took place with the popularization of conscious-patient sedation modalities, particularly by the inhalation route in offices not offering general anesthesia. The patient-completed short-form medical history has become very nearly a standard of care in such offices, followed closely by preoperative determination of blood pressure and perhaps one or more additional vital signs. Intraoperative monitoring has also enormously increased in such offices, as knowledge and experience with conscious-patient sedation has multiplied. By intraoperative monitoring I mean far more than vital signs, but general observation monitoring as well. Bennett puts this so well when, in his discussion of conscious-patient sedation (both inhalation and intravenous), he states that, because consciousness is maintained and protective reflexes remain intact, continual monitoring of vital signs is not necessary.3 He suggests palpation of the pulse at the carotid artery or other locations if desired, and he advises leaving the blood pressure cuff on the arm


and checking occasionally if desired. Benamplifies the desirability of observation as a primary intraoperative monitoring effort when he states that all patients undergoing nitrous oxide-oxygen consciouspatient sedation should be observed for the presence of three parameters :4 1. Consciousness-all patients must be capable of rational response to command at all times. 2. Comfort-pleasant relaxation is the goal, avoiding intense effect (dysnett

phoric sensations).

3. Cooperation-failing to achieve which, other routes should be considered. The measurement of the preceding three parameters is performed primarily through verbal contact, and is very much a part of direct intraoperative observation mon-

itoring. Before continuing with contemporary monitoring, I would like to state that I totally agree with Mulkey and Hayden who emphasize the primary importance of direct observation monitoring,10 regardless of the modality of pain/anxiety control. This is stressed above biomedical and mechanical monitoring. The following paragraph is summarized from the comprehensive Mulkey-Hayden review. Monitoring of vital signs is a necessary function during all dental therapy, regardless of anesthesia utilized, if any. The degree of surveillance is in direct relation to the degree of pain/anxiety control, and therefore it varies from the totally unmedicated patient through local anesthesia alone, the psychosedation techniques, ultralight general anesthesia, and surgical depth general anesthesia in which an endotracheal tube can be tolerated for restorative dentistry or the peritoneum can be incised. The degree of surveillance also increases with an emergency or with serious disease. The Mulkey-Hayden statement epitomizes one aspect of what this scientific session is all about, namely that there are no monitoring absolutes; there are simply monitoring techniques dictated by training, experience, good judgment, the particular anesthesia or sedation modality, and the physical condition of the patient. I would like to add to that statement the cogent 35

observation of Allen who states that the sine qua non of monitoring is the "degree of change" from control or normnal.2 In today's vernacular, the bottom line of monitoring is the preoperative establishment of baseline vital signs or physiological parameters to be monitored intraoperatively. Monitoring Standards It is my feeling that monitoring standards in dentistry do not exist at this time for the unmedicated patient or for conscious-patient sedation techniques or for ultralight general anesthesia. A case might be made that medical anegthesiology standards apply to surgical depth anesthesia in the dental office, yet even here the standards vary considerably and seem to be greatly influenced by medicolegal experience. It is also my feeling that we should avoid adopting standards, confining ourselves to minimal or desirable guidelines. As might be anticipated under the circumstances of widely burgeoning conscious-patient sedation techniques, the near surfeit of monitoring devices, and the comparative lack of scientific studies on what constitutes intelligent monitoring, we are far from solutions at this stage. This is a good point at which to examine the opinions of a number of experts on monitoring. Macintosh feels that the electronic pulsemeter used during ultralight anesthesia does not add to the security of the patient because its use may lower the attention level of the anesthetist.9 He asks what better monitors are there for the unconscious patient in the dental surgery than the eyes, ears, and fingers of the conscientious anesthetist. It should be pointed out that the British technique known as ultralight anesthesia primarily encompasses what we know as consciouspatient sedation levels, with brief incursions via intermittent methohexital sodium into deeper sedation levels with comparatively depressed protective reflexes. I would not presume to interpret Professor Macintosh's general views on monitoring from the brief reference cited, but it would appear that he is a strong advocate of direct observation monitoring. Hubbell and Royer mention the utility of a pulsemeter for outpatient general 36

anesthesia, but do not make a strong case for its use.8 They emphasize that it is merely an adjunct and does not relieve the dental practitioner and his team of the obligation to supply good anesthesia management via direct observation monitoring. Blatchley5 and the late Drummond-Jack-

son7 seem to take a moderate view with respect to the pulsemeter in ultralight anesthesia, favoring its use as a "constant finger

the pulse." They prefer neither an audible bleep nor a flashing light, but merely a needle moving over a scale within the observer's vision. Allen's position would appear to be considerably more restrictive than the preceding citations.2 He questions the value of the classical operator observation of vital signs, respiratory rate, cardiac rate, and blood pressure as an index of tissue function. He states that the ideal mechanical monitor does not exist at this time, and he suggests that we redirect our thinking from macroscopic to microscopic and biochemical monitoring. Allen emphasizes that the ultimate efficiency of any monitor can only be as vigilant, as foolproof, and as accurate as the alterness and knowledge of the anesthetist. Trieger takes a moderate view of continuous intraoperative monitoring,1' and it is one which I share. He points out the value of continuous monitoring by pulsemeter, precordial stethoscope, and the electrocardioscope, although he does not state that any one of the devices is necessary. Trieger rightfully makes a plea to accept, not resist, changes in anesthesia techniques and armamentarium when they are shown to provide better and safer services for patients. It is obvious from the foregoing that no recognizable minimal guidelines of )nonitoring exist in dental anesthesiology at this time. However, it would seem only prudent for the dental practitioner utilizing conscious-patient sedation to establish baseline vital signs prior to therapy, and to be prepared to monitor vital signs intraoperatively if indicated by circumstances. For the practitioner utilizing ultralight general anesthesia, it would appear desiraon


ble to follow the identical preceding routine and to consider continuous cardiac monitoring by one of the several devices, with the proviso that ECG capability could be considered helpful under certain conditions. For all dental practitioners, I feel that it is desirable to determine vital signs during the initial physical evaluation, and to repeat at least the blood pressure prior to significant dental therapy, whether or not systemic drugs are utilized. While we are a long way from having reached these desirable guidelines in dentistry, we have made almost unbelievable progress in the past 25 years, and I feel that the realization of these goals is far closer than 25 years in the future. The Future The future of monitoring is as exciting as the past, but I expect that future instrumentation changes will come even more rapidly than those of the past 10 years. We are presently in the third generation of electronic monitoring instruments. Those of 10 years ago are literally medieval by comparison. We are now at the technological point where literally any physiological parameter can be monitored, including cardiac output, acid-base balance, and levels of CNS depression. Monitor requirements of accuracy, simplicity, reliability, easy placement, and cost-effectiveness are the only barriers, and they are rapidly being solved. I don't look for the machines to control either anesthesia or sedation, but the next generation will make for far safer and more relaxed practice. Summary Monitoring in dental anesthesiology was defined, its phenomenal growth in recent years was analyzed, various systems were generally reviewed, past and present state of the art was discussed in detail, predictions were made about future instrumentation, and the wide diversity of opinions regarding desirable guidelines was explored. Address reprint requests to: Dr. Frank M. McCarthy USC School of Dentistry 925 West 34th Street Los Angeles, CA 90007


REFERENCES 1. Adriani J Techniques and Procedures of Anesthesia Springfield Ill Charles C Thomas 1964 p 60. 2. Allen G D Dental Anesthesia and Analgesia Baltimore Williams & Wilkins Co. 1972 p 47-57. 3. Bennet C R Conscious-Sedation in Dental Practice St. Louis C V Mosby Co 1974 p 160-1. 4. Ibid p 84-6. 5. Blatchley D Open letter to Professor Sir Robert Macintosh, Digest, Soc for the Advan of Anaes in Dent 3:65 July 1976. 6. Council on Dental Therapeutics Accepted Dental Therapeutics 36th ed Chicago Amer Dent Assoc 1975 p 5-7. 7. Drummond-Jackson S L Intravenous Anaesthesia 5th ed London Soc for the Advan of Anaes in Dent 1971 p 310. 8. Hubbell A 0 and Royer R 0 A Method of outpatient general anesthesia for the oral surgical patient, in Jorgenson N B and Hayden J Sedation, Local and Genieral Anesthesia in Dentistry 2nd ed Phila Lea & Febiger 1972 p 100. 9. Macintosh R R Bleeps Soc for the Advan of Anaes in Dent 3:65 July 1976. 10. Mulkey T F and Hayden C L Monitoring in McCarthy F.M. (ed.) Emergencies in Dental Practice 2nd ed Phila W B Saunders Co 1972 p 42-76. 11. Trieger N Why monitor? Anes Prog 23:139 Sept-Oct 1976.

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Monitoring in dentistry--an overview.

MONITORING IN DENTISTRY - AN OVERVIEW Frank M. McCarthy, M.D., D.D.S.* Introduction Adriani defines monitoring thusly-"The term monitoring refers to...
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