Monitoring During Sedation

chapter 5  Monitoring During Sedation CHAPTER OUTLINE ROUTINE PREOPERATIVE MONITORING Pulse (Heart Rate and Rhythm) Blood Pressure Electrocardiography Ventilation Pulse Oximetry Carbon Dioxide Monitoring

T

he improvement of monitoring techniques and adoption of practice guidelines have advanced the safety of anesthesia and decreased mortality and morbidity.1,2 A study of 359 preventable anesthesia incidents concluded that human error contributed to 82% of negative outcomes.3 Many of these errors are caused by inadequate attention to details. Anesthesia— in all its clinical forms—is an art that encompasses collecting and analyzing information, then discerning and carrying out appropriate interventions. Careful attention and adequate understanding of how to monitor a patient can reduce human errors and adverse effects. Monitoring is an essential aspect of sedation care. The word monitor comes from the Latin monere, meaning “to remind, admonish.” It is an active process of identifying changes in physiological effects. Early recognition of pathologic physiological effects can reduce the likelihood of poor outcomes through early intervention. Patients receiving anesthesia must be carefully monitored for its effects on the central nervous system (CNS), cardiovascular system, and respiratory system. Anesthesia suppresses many of the body’s normal automatic functions and may significantly affect the patient’s breathing, heart rate, blood pressure, and other vital functions. Early detection of adverse side effects allows corrective measures to be instituted in a timely fashion when they are more likely to be effective and prevent serious complications from arising. Early recognition and treatment of an anesthesia urgency can prevent it from becoming an anesthesia emergency.

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Bispectral Electroencephalographic Monitoring (BIS Monitoring) Temperature Other Monitoring Devices and Techniques RECORDKEEPING Sedation Record General Anesthesia Record

Monitoring standards in dentistry derive from state laws, regulatory agencies, and professional societies. Standards for basic anesthetic monitoring are set by the Subcommittee of Standards and Practice Parameters of the American Society of Anesthesiologists (ASA). These standards were established in 1986 and have evolved with the implementation of new technology and practices. Last affirmed October 28, 2015, today’s standards center on behaviors necessary to provide maximum possible warning of untoward events.4 These standards highlight the importance of quality patient care, frequent measurements, and incorporating clinical judgment and expertise. The ASA requires that two standards be met4: Standard I – Mandates that qualified anesthesia personnel shall be present in the room throughout the delivery of general anesthesia, regional anesthesia, and monitored anesthesia care. Standard II – Requires continually evaluating the patient’s oxygenation, ventilation, circulation, and temperature. It is important to note that continuous is defined as “prolonged without any interruption in time” and continual is defined as “repeated regularly and frequently in steady rapid succession.” The ASA monitoring standards allow, under extenuating circumstances, the responsible anesthesiologist to waive certain requirements if absolutely necessary, but this event must be stated in a note in the patient’s medical record and must include the reason for the waiver.4 The ASA guidelines are listed in Box 5.1.

CHAPTER 5  Monitoring During Sedation



Box 5.1 

Standards for Basic Anesthetic Monitoring4

These standards apply to all anesthesia care although, in emergency circumstances, appropriate life support measures take precedence. These standards may be exceeded at any time based on the judgment of the responsible anesthesiologist. They are intended to encourage quality patient care, but observing them cannot guarantee any specific patient outcome. They are subject to revision from time to time, as warranted by the evolution of technology and practice. They apply to all general anesthetics, regional anesthetics, and monitored anesthesia care. This set of standards addresses only the issue of basic anesthetic monitoring, which is one component of anesthesia care. In certain rare or unusual circumstances, 1) some of these methods of monitoring may be clinically impractical, and 2) appropriate use of the described monitoring methods may fail to detect untoward clinical developments. Brief interruptions of continual† monitoring may be unavoidable. These standards are not intended for application to the care of the obstetrical patient in labor or in the conduct of pain management. 1.  Standard I Qualified anesthesia personnel shall be present in the room throughout the conduct of all general anesthetics, regional anesthetics, and monitored anesthesia care. 1.1 Objective Because of the rapid changes in patient status during anesthesia, qualified anesthesia personnel shall be continuously present to monitor the patient and provide anesthesia care. In the event there is a direct known hazard, e.g., radiation, to the anesthesia personnel which might require intermittent remote observation of the patient, some provision for monitoring the patient must be made. In the event that an emergency requires the temporary absence of the person primarily responsible for the anesthetic, the best judgment of the anesthesiologist will be exercised in comparing the emergency with the anesthetized patient’s condition and in the selection of the person left responsible for the anesthetic during the temporary absence. 2.  Standard II During all anesthetics, the patient’s oxygenation, ventilation, circulation, and temperature shall be continually evaluated. 2.1 Oxygenation 2.1.1 Objective To ensure adequate oxygen concentration in the inspired gas and the blood during all anesthetics. †

2.2 Methods 2.2.1 Inspired gas: During every administration of general anesthesia using an anesthesia machine, the concentration of oxygen in the patient breathing system shall be measured by an oxygen analyzer with a low oxygen concentration limit alarm in use.* 2.2.2 Blood oxygenation: During all anesthetics, a quantitative method of assessing oxygenation such as pulse oximetry shall be employed.* When the pulse oximeter is utilized, the variable pitch pulse tone and the low threshold alarm shall be audible to the anesthesiologist or the anesthesia care team personnel.* Adequate illumination and exposure of the patient are necessary to assess color.* 3. Ventilation 3.1 Objective To ensure adequate ventilation of the patient during all anesthetics. 3.2 Methods 3.2.1 Every patient receiving general anesthesia shall have the adequacy of ventilation continually evaluated. Qualitative clinical signs such as chest excursion, observation of the reservoir breathing bag, and auscultation of breath sounds are useful. Continual monitoring for the presence of expired carbon dioxide shall be performed unless invalidated by the nature of the patient, procedure, or equipment. Quantitative monitoring of the volume of expired gas is strongly encouraged.* 3.2.2 When an endotracheal tube or laryngeal mask is inserted, its correct positioning must be verified by clinical assessment and by identification of carbon dioxide in the expired gas. Continual end-tidal carbon dioxide analysis, in use from the time of endotracheal tube/laryngeal mask placement, until extubation/removal or initiating transfer to a postoperative care location, shall be performed using a quantitative method such as capnography, capnometry, or mass spectroscopy.* When capnography or capnometry is utilized, the end tidal CO2 alarm shall be audible to the anesthesiologist or the anesthesia care team personnel.* 3.2.3 When ventilation is controlled by a mechanical ventilator, there shall be in continuous use a

Note that “continual” is defined as “repeated regularly and frequently in steady rapid succession,” whereas “continuous” means “prolonged without any interruption at any time.” *Under extenuating circumstances, the responsible anesthesiologist may waive the requirements marked with an asterisk (*); it is recommended that when this is done, it should be so stated (including the reasons) in a note in the patient’s medical record. From the American Society of Anesthesiologists, Committee on Standards and Practice Parameters: Standards for Basic Anesthetic Monitoring, Park Ridge, IL, October 28, 2015, American Society of Anesthesiologists.

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68 Box 5.1 

CHAPTER 5  Monitoring During Sedation

From the Standards for Basic Anesthetic Monitoring4—cont’d

device that is capable of detecting disconnection of components of the breathing system. The device must give an audible signal when its alarm threshold is exceeded. 3.2.4 During regional anesthesia (with no sedation) or local anesthesia (with no sedation), the adequacy of ventilation shall be evaluated by continual observation of qualitative clinical signs. During moderate or deep sedation the adequacy of ventilation shall be evaluated by continual observation of qualitative clinical signs and monitoring for the presence of exhaled carbon dioxide unless precluded or invalidated by the nature of the patient, procedure, or equipment. 4. Circulation 4.1 Objective To ensure the adequacy of the patient’s circulatory function during all anesthetics. 4.2 Methods 4.2.1 Every patient receiving anesthesia shall have the electrocardiogram continuously displayed from

Guidelines that specify requirements for monitoring patients during various levels of sedation and general anesthesia in dentistry have been published by the American Dental Association (ADA) and several other dental specialty organizations.5,6 In general, all are consistent with guidelines suggested by the ASA4 and take into account the unique aspects of sedative and anesthetic care delivery in a dental office setting.6 These guidelines stress the triad of oxygenation, ventilation, and circulation (the airway, breathing, and circulation of basic life support). The American Society of Dentist Anesthesiologists (ASDA) has published parameters of care, as has the American Academy of Pediatric Dentistry (AAPD) and American Association of Oral and Maxillofacial Surgery (AAOMS). According to ADA guidelines, the following functions must be continually assessed7: • Consciousness • Oxygenation • Ventilation • Circulation An apparatus that measures a physiologic function may correctly be termed a monitor only if it delivers an audible and/or visual warning when the measured function falls outside of predetermined parameters (e.g., systolic blood pressure <90 mm Hg or >200 mm Hg). In the absence of a warning system, the device is more a measuring instrument than a

the beginning of anesthesia until preparing to leave the anesthetizing location.* 4.2.2 Every patient receiving anesthesia shall have arterial blood pressure and heart rate determined and evaluated at least every 5 minutes.* 4.2.3 Every patient receiving general anesthesia shall have, in addition to the above, circulatory function continually evaluated by at least one of the following: palpation of a pulse, auscultation of heart sounds, monitoring of a tracing of intraarterial pressure, ultrasound peripheral pulse monitoring, or pulse plethysmography or oximetry. 5.  Body Temperature 5.1 Objective To aid in the maintenance of appropriate body temperature during all anesthetics. 5.2 Methods Every patient receiving anesthesia shall have temperature monitored when clinically significant changes in body temperature are intended, anticipated, or suspected.

monitor. The effectiveness of the monitor usually rests with the person administering the sedation or general anesthesia. Many devices are available to assist in monitoring the sedated or anesthetized patient. In general, these devices are designed to measure the functioning of the following: • CNS • Respiratory system • Cardiovascular system • Temperature Monitors can range from noninvasive to fully invasive as patient need dictates based on anticipated patient risk. Although fully invasive monitors have been shown to provide the highest accuracy, there is an increased risk associated with their placement and use, with complications more likely to develop because of the very nature of the techniques. In addition, invasive monitors are often quite time consuming to prepare for use. For outpatient sedation and anesthesia as used in dentistry and medicine, noninvasive devices have proven over the years to be highly reliable for monitoring patients before, during, and after treatment.8 The requirements of the ideal monitoring device are as follows9: 1. Safe 2. Reliable 3. Noninvasive

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CHAPTER 5  Monitoring During Sedation



4. Easily interpretable 5. Easy to calibrate 6. Stable 7. Portable 8. Easily integrated with other monitoring equipment 9. No technical aid required 10. Inexpensive There have been numerous advancements in technology and equipment over the last two decades. Although higher costs can be a deterrent, there are many benefits to using newer electronic monitors versus standard methods. Electronic monitors may improve a provider’s response time in critical situations by alerting of a possible adverse situation more quickly. Because they measure at frequent and repetitive intervals, without fatigue or distraction, a portion of the human error element is removed. Additionally, many new devices contain Bluetooth components, providing even more versatility and ease of use. No longer are monitors and practitioners tethered to the patient during treatment, limiting access and mobility. Despite these perceived benefits, however, there is little substantiated evidence proving that electronic monitors, by themselves, reduce actual mortality and/or morbidity.10 Ultimately, monitors are one of many means for a practitioner to gather perioperative patient information for interpretation and eventual response. Monitor alarms have sometimes been found to present a challenge for clinicians by paradoxically impairing clinical vigilance, as they may have difficulty differentiating an alarm tone from regular frequencies.11 Known as “alarm fatigue,” practitioners may adjust to the stimulation of constant sounds of monitors by tuning out, causing them to miss a crucial alarm. One study reported 80 monitor-related deaths over the course of 3.5 years, with alarm fatigue identified as the most frequently contributing factor.12 In 2014 the ECRI Institute, a nonprofit that researches patient care improvement, identified alarm fatigue as the number-one health technology hazard in patient care.13 Adjusting parameters to match the individual patient’s traits and status can help counteract this problem.

ROUTINE PREOPERATIVE MONITORING Before treating any dental or medical patient, baseline vital signs should be established as a part of the routine pretreatment

patient evaluation (see Chapter 4). Vital signs recorded at this pretreatment visit include blood pressure, heart rate and rhythm, and respiratory rate. Additional vital signs to be monitored as indicated include temperature, height, and weight. Baseline SpO2 (oxygen saturation levels) should be recorded in patients with respiratory issues and those with congenital cardiac defects. These values should be recorded in the patient’s chart (Fig. 5.1) to serve as a point of reference against which subsequent values obtained during treatment may be compared. Baseline vital signs should be recorded at a nonthreatening time when they are likely to represent “normal” for that patient. A patient’s initial visit to the dental office, a time when no invasive dental care is planned, is more likely to provide reliable vital sign values.

Pulse (Heart Rate and Rhythm) Monitoring of the pulse is recommended for all patients as a part of their routine preoperative evaluation (see Chapter 4). During general anesthesia, circulatory function must be continually evaluated. Preoperative values below 60 or greater than 110 beats per minute (in adult patients) should be evaluated before treatment is started. Preoperative recording of the heart rate and rhythm should be made whenever any drug is to be administered. In adult patients, heart rate and rhythm should be monitored at regular 5-minute intervals during intramuscular (IM), intranasal (IN), and intravenous (IV) moderate sedation. In techniques of deep sedation or general anesthesia in which a more profound level of CNS depression is sought (such as IV sedation), continuous monitoring is mandatory. The heart rate and rhythm can be measured manually or electronically. When measuring manually, the fleshy portions of two fingers are gently placed over a superficial artery for 30 seconds. Arteries that are accessible for monitoring of the pulse are listed in Table 5.1. The radial and brachial arteries are most frequently used during routine procedures, whereas the facial or labial arteries are accessible when working in or around the oral cavity. Palpation of the carotid artery is usually reserved for emergency situations. Locations of arteries are listed in Fig. 5.2. It is suggested that the provider palpate a large artery on the patient at the start of a procedure so that he or she will know its precise location at a later time when perhaps conditions

ASA I

1

CURRENT MEDICAL PROBLEMS 1

II

2

2

III

3

3

IV

4

4

CURRENT MEDICATIONS BP

HT

PULSE

WT

RESP.RATE

TEMP

Figure 5.1  Baseline vital signs are recorded on the patient’s dental chart.

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Table 5.1 

CHAPTER 5  Monitoring During Sedation

Arteries Employed for Pulse Determination

ARTERY

LOCATION

Radial Brachial Carotid

Ventrolateral wrist Medial antecubital fossa Groove between trachea and sternocleidomastoid muscle in neck Upper lip Cheek Anterior to tragus of ear

Labial Facial Superficial temporal

have deteriorated and the pulse may be weak or absent or the monitor malfunctions. A rough but consistent estimate of systolic blood pressure may be obtained via palpation of three of the aforementioned arteries. When a radial artery pulse is palpable, the systolic blood pressure is at least 80 mm Hg. A brachial artery pulse will be palpable at a systolic pressure of 70 mm Hg, and a carotid artery pulse is present at a systolic reading of 60 mm Hg.14 Therefore, if both the carotid and brachial pulses are present but the radial pulse is absent, it can be stated that (barring anatomic anomalies) the systolic blood pressure is greater than 70 mm Hg (brachial), but less than 80 mm Hg (radial). This technique is used almost exclusively in emergency situations in which a blood pressure monitoring apparatus is not immediately available or in which it is impossible to hear the sounds produced. Pulse monitors provide a continuous measurement of the heart rate. These devices usually involve a simple electromechanical or optical transducer that is placed on a patient’s fingertip or earlobe. A photoelectric beam is interrupted by the flow of blood through the finger following each contraction of the heart. This interruption produces a visual and/or audio signal. In addition to their primary function(s), many monitoring devices, such as the pulse oximeter, automatic vital signs monitor, and the electrocardiograph (ECG), also measure the heart rate. Either a digital display or a graph on an oscilloscope is provided.

Blood Pressure Along with heart rate and rhythm, monitoring blood pressure gauges the status of a patient’s cardiovascular system (see Chapter 4). Blood pressure should be determined for all prospective dental patients as part of a pretreatment physical evaluation. When moderate sedation techniques are implemented, particularly those in which more profound levels of CNS depression are expected, such as the parenteral moderate sedation techniques (IM, IN, IV), blood pressure must be monitored more frequently. Specifically, it is recommended

Figure 5.2  Pulse pressure points. (From Patton KT, Thibodeau GA: Anatomy & physiology, ed 9, St Louis, 2016, Elsevier.)



CHAPTER 5  Monitoring During Sedation

that blood pressure be recorded every 5 minutes for the duration of the procedure, as well as immediately following the administration of any drug. The deeper the level of sedation and the less able the patient is to respond appropriately to verbal command, the more crucial it becomes for frequent blood pressure monitoring. During deep sedation and general anesthesia, blood pressure is monitored and recorded at 5-minute intervals. Several methods exist to monitor blood pressure. A preferred method involves auscultation through the use of a stethoscope and sphygmomanometer (blood pressure cuff). An appropriately sized blood pressure cuff, encompassing 80% or more of the patient’s upper arm circumference,15 is typically applied for the duration of the procedure. It should be placed on the arm closest to the examiner. However, when an IV infusion is in place, the blood pressure cuff should, whenever possible, be placed on the opposing arm to prevent a temporary occlusion of the IV line whenever the cuff is inflated. The same is true when a pulse oximeter is used on a finger, as inflation of the blood pressure cuff results in obstruction of the underlying blood flow into the distal extremity, thus causing a deceptive drop in peripheral capillary oxygen saturation. This perceived fall in oxygen saturation frequently results in activation of the monitor’s alarm system and thus presents the need for a practitioner to assess accuracy. Korotkoff sounds result from turbulent blood flow from a compressed artery by a blood pressure cuff. Auscultation for Korotkoff sounds will allow for an approximate measurement of both systolic and diastolic blood pressure. The appearance of the first Korotkoff sounds represents the systolic pressure, whereas muffling or disappearance of the sound indicates the diastolic blood pressure.10 Concerns with auscultation of Korotkoff sounds include falsely high blood pressure estimates when the blood pressure cuff is too small, applied too loosely, or when the extremity is below heart level. Conversely, falsely low estimates can occur when the cuff is too large, when the extremity is above heart level, or after quick deflations.10 This technique requires palpation and auscultation of pulsatile blood flow and can be problematic during conditions of low blood pressure. In some situations, particularly with markedly obese individuals, it may be extremely difficult, if not impossible, to determine blood pressure accurately using auscultation. If this is the case, a palpatory blood pressure may be employed. After locating the radial artery in the wrist, the examiner should rapidly inflate the blood pressure cuff until the pulse disappears, continuing to inflate for an additional 20 to 30 mm Hg. While keeping his or her fingers over the radial artery, the examiner slowly decreases the pressure in the cuff until a pulse is felt. A relatively accurate systolic blood pressure may be obtained in this manner; however, no diastolic pressure is obtainable using this method. When this technique is used, a note should be entered in the anesthesia record, such as SYS BP: 130 mm Hg (palpation). Alternatively, altering the placement of the cuff to the wrist or ankle may be effective.

71

Figure 5.3  Mindray T1 monitor (ECG, SpO2, temp, BP).

Blood pressure may also be monitored using automatic devices. In the late 1970s these microprocessor-controlled oscillotonometers largely replaced auscultatory and palpatory techniques for perioperative blood pressure monitoring. These devices measure mean arterial pressure (MAP) by sensing the point of maximal fluctuations in cuff pressure while deflating. Some devices simply require the inflation of the blood pressure cuff, after which the cuff’s deflation becomes automatic. Pressure is released slowly, and auditory (beeping) and visual (flashing light) displays announce the systolic and diastolic pressures (and in many cases the heart rate, too). The cuff pressure is then sent to a transducer whose output is digitized for processing. The cuff is inflated and pressure is held while oscillations are sampled. If no oscillations are sensed, the microprocessor switches open a deflation valve and proceeds to the next pressure level for sampling. The microprocessor then compares the amplitude of oscillation pairs and numerically displays the blood pressure estimate. Digital readouts are available on most of these devices, and many also provide a printed record. In recent years, second-generation blood pressure monitoring devices appear to be more reliable than earlier models. In addition, the cost of these instruments has become significantly more reasonable. Most of the newer blood pressure monitors can be programmed to record blood pressure at regular intervals (e.g., every 5 minutes). Some devices combine several functions. The device shown in Fig. 5.3 integrates blood pressure, heart rate, ECG, O2 saturation, and temperature into one unit. The size and weight of monitors have also dramatically decreased in recent years. More manufacturers are emphasizing portability and modularity in new models. It is strongly recommended that providers utilize authentic medical device blood pressure monitors and not those that are marketed for retail sales. The over-the-counter versions

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CHAPTER 5  Monitoring During Sedation

have been shown to be less accurate in cases of hypotension and are unreliable in instances of cardiac dysrhythmia. Continuous noninvasive arterial blood pressure measurement (CNAP) is the latest development in noninvasive blood pressure monitoring. CNAP measures blood pressure continuously in real time and monitors without latency, much like a fully invasive arterial catheter system (not routinely used in dental sedation), yet it is completely noninvasive. It provides an accurate display of the arterial blood pressure trace with beat-to-beat blood pressure monitoring. Studies have shown accuracy even in instances of rapidly fluctuating hemodynamics.9

Electrocardiography The ECG (Fig. 5.4) monitors both the heart rate and rhythm and provides a warning of the development of changes in the electrical activity of the myocardium. Patients with cardiac history or symptoms should have an ECG before sedation. Although 12 leads may be used, lead II (right arm → left leg) is most commonly used during anesthesia because it readily permits detection of dysrhythmias. Textbooks on basic electrocardiography are available, enabling the reader to become proficient in the interpretation of ECG tracings. Normal sinus rhythm is illustrated in Fig. 5.5 and premature ventricular contractions (PVCs) in Fig. 5.6.

Although not required for use in all levels of sedation, the ECG does increase one’s ability to detect possibly significant changes in functioning of the myocardium at a time when corrective treatment may usually restore a normal rhythm. The appearance of dysrhythmias is more likely during general anesthesia than during moderate sedation. Three common causes of dysrhythmias are: 1. Hypoxia, leading to myocardial ischemia 2. Endogenous catecholamine release, secondary to inadequate pain control or too light a level of CNS depression 3. Hypercapnia, resulting from poor ventilation Management of dysrhythmias secondary to these causes, which are usually readily correctable, is done through: 1. Ensuring airway management and ventilation 2. Providing adequate pain control (e.g., local anesthesia) 3. Increasing the level of anesthesia (greater CNS depression) Recommendations for the use of the ECG during sedation and anesthesia are found in Tables 5.2 and 5.3.

Ventilation Of equal, if not greater, importance to monitoring cardiovascular function during sedative and general anesthetic procedures is monitoring the patient’s respiratory status. Because all sedative and general anesthetic agents are CNS and respiratory

Multifocal PVCs QRS P

PVC T

PVC

Couplet

Ventricular tachycardia

Figure 5.4  Vital signs monitor, includes ECG (arrow). Ventricular bigeminy R-on-T

R P

T

QS Ventricular trigeminy

Figure 5.5  Normal sinus rhythm. (From Lewis SL et al: Medical-surgical nursing: assessment and management of clinical problems, ed 7, St Louis, 2007, Mosby.)

Figure 5.6  Premature ventricular contractions. (From Lewis SL et al: Medical-surgical nursing: assessment and management of clinical problems, ed 7, St Louis, 2007, Mosby.)

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CHAPTER 5  Monitoring During Sedation



Table 5.2 

Recommended Monitoring for Adult Patients Technique

MONITOr

LOCAL ANESTHESIA Pr In Po

Pr In Po

Pr

Heart rate

** 0 *

** 0 *

Blood pressure

** *

** * *

ECG respiration

0 ** V 0 *

** ** ** q 5 min ** ** ** q 5 min * * 0 ** ** ** V PTV * ** ** * 0 0

Oximetry Temperature

*

0 0 0 0 0 0 0 0

ORAL

0 ** V 0 *

IM/IN

0 0 0 0 * 0 0 0

General Anesthesia INHALATION

In Po

Pr

IV

In Po

** ** q 5 min ** * q 5 min 0 0 ** * V V 0 0 * 0

Pr

**

OUTPATIENT

In Po

Pr

** ** ** Cont. ** ** ** q 5 min * * * ** ** ** V PT V * ** ** * 0 0

** 0 ** V 0 0

In Po

** ** ** Cont. ** ** ** q 5 min ** ** ** ** ** ** V PT V ** ** ** ** * *

INPATIENT Pr

In

** ** Cont. ** ** q 5 min ** ** ** ** V PT/E ** ** ** **

Po ** ** ** ** V ** *

0, Not essential; *, optional; **, recommended, Pr, preoperative; In, intraoperative; Po, postoperative; Cont., continuous; V, visual; PT, pretracheal stethoscope; E, esophageal stethoscope. Heart rate: Heart rate may be monitored by palpation in both the preoperative and postoperative periods; however, it is suggested that when the heart rate is monitored intraoperatively, an electrical monitor providing a continuous reading be used. Devices such as a pulse meter, pulse oximeter, capnograph, and ECG provide continuous heart monitoring. Blood pressure (BP): When the recommendation for monitoring BP is **, I suggest that the BP cuff be kept on the patient’s arm throughout the entire procedure. Electrocardiograph (ECG): The ECG provides continuous monitoring of the electrical activity of the heart and the heart rate. Respiration: Visual monitoring implies a casual observation of the movements of the patient’s chest for 30–60 seconds. PT, pretracheal stethoscope, provides instantaneous evaluation of breath sounds and respiratory rate. E, the esophageal stethoscope, is inserted into the esophagus during general anesthesia, providing excellent sound quality for both heart and lung sounds. Oximetry: Oximetry provides continuous monitoring of arterial O2 saturation. Temperature: Preoperative temperature monitoring may be done manually, but if intraoperative monitoring of body temperature is required, it is more readily achieved continuously via rectal or esophageal probe.

Table 5.3 

Recommended Monitoring for Pediatric Patients Technique

MONITOR

LOCAL ANESTHESIa

ORAL

Pr In Po

Pr

Heart rate

** 0 *

Blood pressure

** *

ECG respiration

0 ** V 0 *

** ** Cont. ** ** q 5 min 0 0 ** ** V PT ** ** * 0

Oximetry Temperature

*

0 0 0 0 0 0 0 0

Refer to footnotes in Table 5.2.

IM/IN

In Po ** ** 0 ** ** 0

Pr

In Po

** ** ** Cont. ** ** ** q 5 min * * 0 ** ** ** V PT V * ** ** * * *

General Anesthesia INHALATION Pr

In

** ** Cont. ** ** q 5 min 0 0 ** ** V V/PT 0 0 * 0

IV

OUTPATIENT

Po

Pr

**

** ** Cont. ** ** q 5 min * * ** ** V PT * ** * *

** 0 ** V 0 0

In Po ** ** * ** V ** *

Pr

INPATIENT

In Po Pr

** ** ** Cont. ** ** ** q 5 min ** ** ** ** ** ** V PT V ** ** ** ** ** **

In

Po

** ** ** Cont. ** ** ** q 5 min ** ** ** ** ** ** V PT/E V ** ** ** ** ** **

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CHAPTER 5  Monitoring During Sedation

depressants to a greater degree than they are cardiovascular depressants, respiratory changes are usually observed well before cardiovascular changes. Alterations in cardiac rhythm (dysrhythmias) observed on the ECG in the ASA 1 or 2 patient are likely to be produced by myocardial ischemia, which is most often secondary to respiratory depression or inadequate ventilation directly related to the drugs that have been administered. Morbidities and mortalities occur secondary to respiratory depression (or arrest) that goes unrecognized for too long, followed by an ineffective response when finally recognized. Casual monitoring of respiratory adequacy by observation of the rise and fall of the patient’s chest or by observation of the color of oral mucous membranes is unreliable and cannot be used as the sole method of monitoring respiratory status. Respiratory adequacy may be crudely monitored by: 1. Determining the respiratory rate 2. Observing chest wall motion 3. Observing the color of the mucous membranes (oral membranes and fingernail beds) 4. Observing the inflation and deflation of the reservoir bag on the inhalation sedation unit—if inhalation sedation or O2 is administered (and if the patient is breathing through his or her nose, not breathing through the mouth) It must always be remembered that movement of the chest wall is not an absolute guarantee of air exchange between the lungs and the external environment. Chest wall movement indicates that a mechanical effort is being made to exchange air and that respiratory arrest has not occurred. The practitioner should be aware that the airway may be completely obstructed (e.g., tongue, foreign body) with no air exchange in the presence of spontaneous respiratory efforts. In addition, respiratory efforts normally indicate that cardiac arrest has not yet occurred because the primary cause of cardiac arrest during sedation and general anesthesia is the occurrence of acute dysrhythmias resulting from ischemia of the myocardium secondary to either respiratory arrest or airway obstruction. Respiratory arrest usually appears before cardiac arrest. Similarly, observing the color of mucous membranes as a respiratory monitor is unreliable because cyanosis is not observed until some time after the patient has become hypoxic. In addition, placement of a rubber dam is indicated during many dental procedures, especially in patients receiving parenteral moderate or deep sedation or general anesthesia. The rubber dam conceals the lips and intraoral soft tissues, preventing this as a means of monitoring. A valid method of determining air exchange is through visualization of the reservoir bag on an inhalation sedation unit or anesthesia machine, provided that an airtight seal of the mask is maintained. If leakage occurs around the sides of the nasal hood or if the patient begins to mouth breathe, the reservoir bag will cease to inflate and deflate during breathing. While operating in the patient’s oral cavity, the dental provider or assistant is able to determine whether air is being

Figure 5.7  Fogging of mirror indicates exchange of air.

Figure 5.8  Hand held in front of patient’s mouth and nose to feel exchange of air.

exchanged by the patient. A mirror held in the patient’s mouth or in front of his or her nose will fog over if air is actively exchanged (Fig. 5.7). More effective is holding a hand in front of the patient’s mouth and nose so that air is felt on the palm of the hand during exhalation if breathing is occurring (Fig. 5.8). The precordial/pretracheal stethoscope is an inexpensive and extremely valuable monitoring device during anesthesia and sedation; it provides constant information concerning upper airway patency, continuous monitoring of heart sounds and ventilation, and a quality assessment of both ventilation efforts and respiration rate. Also, it is the only monitor that allows for detection of fluids in the airway. A weighted stethoscope head (also known as a chest piece or bell) is secured with double-sided adhesive tape (Fig. 5.9) to either the precordial (Fig. 5.10) or pretracheal region (Fig. 5.11) on the patient’s chest.



CHAPTER 5  Monitoring During Sedation

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When used as a pretracheal stethoscope, the weighted head is placed in the midline of the neck over the trachea just superior to the sternal notch (see Fig. 5.11). It lies above the lower end of the trachea at or just slightly above its bifurcation into the right and left main stem bronchi. Tubing connects this stethoscope to a binaural or monaural earpiece. The custom monaural earpiece is preferred because of its comfort and because it permits the user to carry on normal conversation while continually listening for the sounds associated with the exchange of air. Custom earpieces can usually be obtained from companies that manufacture hearing aids (e.g., Miracle Ear, www.miracle-ear.com). A Bluetooth version of a pretracheal stethoscope is also available. Placement in the pretracheal region allows for easy recognition of respiratory sounds, with diminished intensity of heart sounds, which may overwhelm the softer respiratory outputs when placed in the precordial region. It should also be noted that a softening of heart sounds is

often indicative of a drop in blood pressure. The weighted stethoscope head is available in adult and pediatric sizes. When placed in the pretracheal region with double-sided adhesive disks, the pediatric head is adequate for both children and adults. The heavier adult stethoscope head is often uncomfortable for both children and adults. When monitoring breathing, two elements must be considered: 1. Rate of breathing 2. Quality of breath sounds Counting breaths for 15 or 30 seconds and multiplying by 4 or 2, respectively, will calculate the rate in breaths per minute. The most frequent disturbances in respiratory rate are an overly rapid rate (tachypnea) and an unusually slow rate (bradypnea). Tachypnea may indicate the presence of anxiety (e.g., hyperventilation), a pathologic condition (e.g., diabetic acidosis and ketosis), or elevated CO 2 levels; bradypnea is noted

Figure 5.9  Double-sided tape for pretracheal stethoscope.

Figure 5.11  Pretracheal stethoscope on patient’s neck.

Figure 5.10  Precordial stethoscope provides an excellent monitor of both heart and respiratory sounds.

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Table 5.4 

CHAPTER 5  Monitoring During Sedation

Causes of Partial Airway Obstruction

SOUND HEARD

PROBABLE Cause

MANAGEMENT

Snoring

Hypopharyngeal obstruction by the tongue Foreign matter (blood, water, vomitus) in airway Bronchospasm

Repeat head tilt–chin lift

Gurgling

Wheezing

Crowing (highpitched)

Laryngospasm (partial)

Suction airway

Bronchodilator (via inhalation, only if conscious; IM, IV if unconscious) Suction airway; + pressure O2

after the administration of larger doses of an opioid (see Chapter 25). The desired quality of breath sounds is relatively quiet “whooshing” sounds heard within the earpiece, indicating normal, unobstructed airflow and a patent airway. Silence in the earpiece is ominous and must trigger an immediate response. Respiratory obstruction (in the presence of exaggerated ventilatory movements) or respiratory arrest (no chest movements) may have developed and must be immediately corrected, or it may merely be that the stethoscope chest piece has become inadvertently disconnected from the patient. Examples of airway obstruction are found in Table 5.4. Use of the pretracheal/precordial stethoscope decreases the time required for recognition of a potentially serious problem, allowing corrective measures to be implemented more expeditiously. Wheezing indicates partial obstruction in the lower airways (e.g., bronchioles) and is termed bronchospasm (see Chapter 34). Management is required, but bronchospasm is not an immediate, acutely life-threatening situation, unlike complete airway obstruction. Snoring or gurgling (sound of fluid) indicates the presence of a partial obstruction of the upper airway. Snoring most often results when the base of the tongue or the soft palate falls against the posterior pharyngeal wall; oftentimes during treatment dentists inadvertently push the tongue, causing an obstruction. Bubbling, gurgling, or crackling sound of fluid indicates the presence of a liquid (e.g., blood, saliva, water, or vomitus) in the airway. Management of snoring requires elevation of the mandible (head tilt/chin lift), which elevates the base of the tongue off of the posterior pharyngeal wall. When foreign matter is present in the airway of a sedated or unconscious patient, three problems may develop: 1. Aspiration 2. Complete or partial obstruction of the airway 3. Laryngospasm

When the presence of fluid (or other foreign matter) is suspected, immediate management requires suctioning of the posterior pharynx. Normal breath sounds should return once the fluid is removed. Other means of monitoring respiration include impedance pneumography, in which a high-frequency, low-amplitude current is injected across the chest cavity and the resulting voltage is measured. Current flows less easily through the chest as lungs fill, so an increased resistance in voltage indicates an increased lung volume. Similarly, the acoustic respiration rate device uses an adhesive sensor with an integrated acoustic transducer that displays a continuous respiration rate, alerting providers at the first signs of an abnormal or compromised breathing pattern.

Pulse Oximetry Monitoring breath sounds and the rate of respiration, although important to patient care during sedation and anesthesia, does not provide an absolutely accurate assessment of ventilatory efforts. ASA guidelines specifically require the use of an oxygen analyzer with a low concentration–limit audible alarm during general anesthesia and the quantitative assessment of blood oxygenation during any anesthesia care.4 ADA guidelines indicate that when inhalation equipment is used, it must have a fail-safe system that is appropriately checked and calibrated. The equipment must also have either a functioning device that prohibits the delivery of less than 30% oxygen or an appropriately calibrated and functioning in-line oxygen analyzer with audible alarm.7 The color of mucosa, skin, or blood must be continually evaluated, although these are late indicators of desaturation. Pulse oximeters measure pulse rate and estimate oxygen saturation of hemoglobin (Fig. 5.12). They are noninvasive, continuous, autocalibrating, and provide quick response times. The pulse oximeter complements capnography to provide early warning of a desaturation event.16 The Closed Claims Project, established by the ASA to identify the source of complications during anesthesia, conducted an analysis in 1984 and determined that adverse respiratory events accounted for 34% of reported anesthesia claims, of which 85% resulted in brain damage or death. It was later determined that the use of pulse oximetry and capnography monitoring would have likely prevented many of these adverse events. Following the widespread adoption of pulse oximetry and capnography in the mid-1980s, respiratory adverse events decreased from 36% of claims in the 1970s to just 14% of the claims in the 1990s.17 A function of the pulse oximeter—indeed, its primary function during sedation and general anesthesia—is the detection and quantification of hypoxemia. Pulse oximeters measure the oxygen saturation of arterial blood. Oxygen saturation refers to the amount of oxygen carried by hemoglobin. Expressed as a percentage, oxygen saturation is the amount of oxygen carried compared with the total oxygen-carrying capacity of hemoglobin (100%). Breathing ambient air at sea level, an



CHAPTER 5  Monitoring During Sedation

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Red and infrared light source

Red and infrared detector

Figure 5.13  Pulse oximeter measures wavelengths of light passing through the finger.

Figure 5.12  Pulse oximeter. (From Lewis SL et al: Medical-surgical nursing: assessment and management of clinical problems, ed 7, St Louis, 2007, Mosby.)

acceptable normal SpO2 range for a patient without pulmonary pathology is 95% to 99%; acceptable SpO2 ranges decrease as elevation increases.18 The color of blood is a function of oxygen saturation, with a change in color resulting from the optical properties of hemoglobin and its interaction with oxygen. The ratio of oxygenated hemoglobin and reduced hemoglobin can be determined by absorption spectrophotometry—the process of passing two wavelengths of light through the body to a photodetector and measuring the changing absorbance of each of the wavelengths (Fig. 5.13). Pulse oximeters are able to perform a plethysmographic analysis to differentiate the pulsatile hemoglobin saturation from the nonpulsatile signal resulting from absorption and other matter such as skin, muscle, bone, and often nail polish. The pulse oximeter measures the absorption of selected wavelengths of light (660 nm and 910 nm or 940 nm) as they pass through living tissue, such as the fingertip, toe, or earlobe. Oxygenated hemoglobin and hemoglobin absorb these wavelengths of light to differing degrees. The relative percentages

of these two hemoglobins are calculated within the oximeter, and the SpO2 is displayed on the screen.19 Use of pulse oximetry has become the standard of care during moderate sedation, deep sedation, and general anesthesia for all patients. Where state regulation governs the administration of oral sedative drugs to pediatric patients, use of pulse oximetry is mandated. 20 Used in conjunction with the pretracheal/precordial stethoscope, pulse oximetry permits respiratory function of the sedated or anesthetized patient to be accurately and continuously evaluated, adding a level of increased safety to the procedure. As mentioned previously, blood pressure monitoring occludes vascular flow of oxygenated hemoglobin, resulting in a false temporary desaturation. Newer technology has addressed this phenomenon. Massimo SET pulse oximetry utilizes advanced signal postprocessing techniques, which provides more accurate monitoring of arterial oxygen saturation and pulse rate, even during the most challenging conditions, such as times of low perfusion.21 Certain factors may cause inaccurate measurements, such as ill-fitting oximeter probes, excess ambient light, motion artifact (e.g., shivering), and cold extremities, so efforts should be made to minimize these factors.18

Carbon Dioxide Monitoring Noninvasive CO2 monitors have become increasingly popular. Measuring expiratory CO2 is an important part of patient monitoring. The ASA guidelines specifically mandate continuously ensuring the adequacy of ventilation by physical diagnostic techniques during all anesthesia care. Quantitative monitoring of tidal volume and capnography are strongly encouraged in patients undergoing general anesthesia. When administering regional anesthesia or monitored anesthesia care, sufficient ventilation should be assessed by qualitative clinical signs and/ or monitoring of exhaled carbon dioxide. Ensuring correct placement of an endotracheal intubation or laryngeal mask airway requires clinical assessment and qualitative identification

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of carbon dioxide in the expired gas. During general anesthesia, capnography and end-tidal carbon dioxide (ETCO2) analysis are performed.22 Capnometry is the measurement and numeric representation of the CO2 concentration during inspiration and expiration. A capnogram gives a continuous time display of the CO 2 concentration sampled at the patient’s airway during ventilation. Using the principle of infrared absorption, these devices monitor the levels of inspired and ETCO2, providing visual displays as a percentage (%) or millimeters of mercury (mm Hg). Response of the CO2 monitor is virtually instantaneous, assessing every breath taken by the patient. Arterial O2 saturation and respiratory rate are also provided in some models. Audible and visual alarms alert the operator if ETCO2 values are less than or greater than the selected parameters or if apnea occurs. With a gas analyzer, when nitrous oxide (N2O) is administered concurrently, the percentage of N2O is also displayed. Although still not considered the standard of care for moderate parenteral sedation, ETCO2 monitoring has become increasingly recommended in outpatient general anesthesia because it provides yet another noninvasive means of monitoring the patient’s ventilatory status and potentially increasing patient safety. A proposed amendment to the ADA Guidelines for the Use of Sedation and General Anesthesia by Dentists supports the need for the use of capnography during moderate sedation in an open airway system, as well as the need for continual observation of qualitative clinical signs by monitoring for the presence of exhaled carbon dioxide.23 With the development of future generations of CO2 monitors, their use during moderate sedation, deep sedation, and general anesthesia for dentistry is likely to become standard of care.22

Bispectral Electroencephalographic Monitoring (BIS Monitoring)

According to ADA guidelines, the patient’s level of consciousness must be continually monitored.7 The bispectral index (BIS) is one of several technologies used to monitor depth of anesthesia. In the 1990s, medical device company Aspect Medical Systems began a research effort to develop the electroencephalogram (EEG) as a means of monitoring the depth of anesthesia, taking the complex EEG signal and processing the result into a single number, thus providing the anesthetist with a numeric indication of depth of anesthesia.24,25 The Aspect EEG monitor quantitates anesthetic effects on the brain, specifically the hypnotic component of anesthesia. The BIS index is a continuous EEG parameter that ranges from 0 (equivalent to EEG silence or flat line) to 100 (represents an awake CNS).24 Loss of consciousness tends to occur at BIS values between 70 and 80. The manufacturer recommends that a BIS value between 40 and 60 indicates an appropriate level for general anesthesia.25 Clinical correlations of the BIS index are shown in Fig. 5.14. BIS monitoring allows the provider to adjust drugs to the specific needs of the individual patient, possibly resulting in

a more rapid emergence from anesthesia and reducing the incidence of intraoperative awareness.26 Anesthetic techniques consisting of a low or moderate dose of an opioid analgesic and a hypnotic drug (e.g., volatile inhaled anesthetic, IV anesthetic) are the most accurately represented with BIS monitoring. Low opioid doses enable the BIS index to accurately reflect the pharmacodynamics of the hypnotic drugs on the CNS. BIS monitoring, however, has been shown to be less reliable in anesthetics involving higher-dose opioids and is insensitive to several commonly used anesthetic agents such as ketamine and nitrous oxide.27 Intraoperative awareness occurs at a rate of 1 to 2 incidents per 1000 general anesthesia cases,24 thus making BIS monitoring an important dimension of monitoring general anesthesia and providing the anesthetist with the needed feedback to proactively adjust pharmaceutical components. However, in anxiolytic, moderate, and deep sedation cases, the current recommended standard for monitoring patient CNS function is through eliciting patient verbal responses or using physical stimulation to provoke a protective response.

Temperature During all general anesthetics, the means for continuously measuring the patient’s temperature must be available. When changes in body temperature are intended or anticipated, temperature should be continuously measured and recorded on the anesthesia record.28 Monitoring of the patient’s body temperature during parenteral sedation is not usually as critical as are the cardiovascular and respiratory parameters already discussed. However, it is important to determine whether a patient has elevated temperature before the start of the planned treatment. Fever increases the workload of the cardiovascular and respiratory systems. Heart and respiratory rates increase with an increase in body temperature. The patient’s ability to tolerate stress decreases. In the dental office, temperatures were once routinely monitored orally; however, with the newest advances in infrared light transmission, noninvasive arterial thermometers now provide accurate readings from the tympanic, axillary, and temporal regions. For oral monitoring, disposable or nondisposable traditional thermometers may be used. When a nondisposable thermometer is employed, it is placed in the sublingual area for 3 to 5 minutes before reading the temperature. The patient should not have had any hot or cold liquids or foods in his or her mouth immediately before temperature monitoring. Digital nondisposable thermometers are also available, providing a rapid assessment of body temperature. Disposable thermometers using a system of chemicals that melt and recrystallize at specific temperatures have made the monitoring of temperature extremely simple and sanitary. When the unit is placed sublingually, the dots change color within approximately 30 seconds according to the patient’s temperature. When patient compliance is lacking and it is desirable to record the temperature preoperatively, a chemical-dot thermometer may be used by holding the thermal-sensitive strip firmly

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100

Awake, memory intact

Small amplitude, fast frequency wave

BIS=90

100

Awake 80

80

BIS

General anesthesia

Moderate sedation

Deep hypnosis 40

Deep anesthesia

20

Isoelectric EEG

A

BIS=50

General anesthesia

Near suppression Increasing burst suppression

0

60

Large amplitude, slow frequency wave

40 BIS=30

Microvolts

60

BIS=70

20 50

BIS=10

0 50 Seconds

Cortical silence

BIS index range

Sedation

0

B Figure 5.14  A, Clinical correlations of the BIS index. Maintaining the BIS index from 45 to 60 during general anesthesia appears to ensure unconsciousness with a hypnotic-opioid anesthetic technique while providing for rapid emergence. B, Electroencephalographic (EEG) changes observed with increasing depth of anesthesia. (Adapted from Johansen JW, Sebel PS: Development and clinical application of electroencephalographic bispectrum monitoring. Anesthesiology 93:1336, 2000.) (Redrawn from Kelley SD: Monitoring level of consciousness during anesthesia and sedation, Natick, MA, 2003, Aspect Medical Systems.)

against the patient’s dry forehead for about 15 seconds. Color changes in the strips occur, indicating the patient’s temperature. Because forehead temperatures are less than an actual core temperature reading, chemical-dot thermometers have been adjusted to accommodate for this difference (of about +4.5° F, or +2.5° C). Noncontact infrared thermometers allow practitioners to measure temperature from a distance, providing a quick, noninvasive method of obtaining patient temperature by converting radiant power to an electrical signal that is displayed in units of temperature after compensating for ambient temperature (Fig. 5.15). This is a preferred method as it is nondisposable yet requires no sterilization between uses and has been shown to have the same accuracy as measurements taken via rectal mercury thermometers.29 The importance of monitoring temperature intraoperatively during general anesthesia is based on the need to prevent severe hypothermia, which develops as body heat is dissipated, and to monitor the possible development of malignant hyperthermia (hyperpyrexia), a serious complication during general anesthesia. Even minimal fluctuations (1.9° C) in core body temperature during the perioperative period have been shown to inhibit wound healing and increase postoperative complications.30 Monitoring of the body temperature is a standard of care in pediatric general anesthesia.28

Figure 5.15  Noncontact infrared thermometer. (Photo © gettyimages. com.)

Other Monitoring Devices and Techniques

Other monitoring devices and techniques are available. However, the necessity of using them during the typical outpatient procedure on an ASA 1, 2, or 3 risk patient in the dental or medical office environment is questionable. These additional procedures include monitoring of central venous pressure (CVP) as a measure of right-side heart filling

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pressures as a guide to intravascular volume. An elevated CVP indicates circulatory overload (as in heart failure), whereas a low CVP indicates reduced blood volume. Monitoring CVP necessitates the passage of a catheter from either the subclavian or internal jugular vein approximately 10 to 15 cm to the junction of the superior and inferior venae cavae and the right atrium. CVP monitoring is not recommended for use in ASA 1, 2, or 3 patients undergoing elective treatment under general anesthesia. The level of CNS depression may be monitored through the use of the (noninvasive) EEG. Predictable changes are noted in the EEG with different anesthetic agents.22 The need for EEG monitoring during sedative and most outpatient general anesthetic procedures is minimal, and it is not recommended. Before reviewing the various techniques of sedation and general anesthesia with recommendations for monitoring for each, it must be emphasized that the most important system to monitor is the CNS, the one that is targeted for depression in our techniques. Therefore, the most important technique of patient monitoring during any sedation technique remains direct communication between the patient and the doctor. The ability of the moderately sedated patient to respond appropriately to command is an integral part of the definition of consciousness presented in Chapter 2. Lack of such an appropriate response is a call for immediate action to determine (and correct, if necessary) the cause of the lack of response. Direct communication with the patient is a means of determining the level of functioning of the CNS. Because virtually all drugs used in sedation and/or general anesthesia act primarily by depressing the CNS (this is their raison d'être), it is appropriate that the importance of monitoring the CNS be recognized. Monitoring of the respiratory and cardiovascular systems, though important, is considered secondary to CNS monitoring during minimal sedation (e.g., oral benzodiazepine or N2O-O2 inhalation sedation). As the level of CNS depression increases when moving from moderate to deep sedation, the patient’s ability to respond appropriately is increasingly diminished, warranting an intensification of monitoring of “other systems”—respiratory and cardiovascular. Generalizing to a slight degree, most drugs used during sedation and general anesthesia (CNS depressants) depress breathing to a greater degree—often at sedative doses—than they depress the cardiovascular system, thus the emphasis on more intensive monitoring of respiratory function than of the cardiovascular system during moderate sedation. With the loss of consciousness, however, effective communication with the patient is lost, and the doctor must rely solely on respiratory and cardiovascular monitoring to assess the patient’s clinical status. Monitoring the pediatric patient proves to be somewhat more difficult if the patient presents a significant management problem. When oral, IN, or IM sedation is to be employed, the patient may be combative, crying, or screaming, making it virtually impossible for the recommended baseline vital signs

to be obtained. Although determining these parameters may be difficult or impossible, there actually is little necessity to monitor the vital signs of the patient during the immediate preoperative period when he or she is extremely active, because the patient’s baseline vital signs have (hopefully) been recorded at the preoperative visit to the office. Monitoring of the patient, pediatric and adult, becomes increasingly more important when the patient, under the influence of the administered CNS depressant drugs, becomes quiescent and cooperative. Once this state is achieved (when dental care can commence), the doctor must become more vigilant in monitoring the parameters recommended (CNS, respiratory, cardiovascular). As with the sedated adult patient, monitoring of respiration becomes more critical as the level of sedation deepens. Some pediatric sedation techniques include the administration of opioid agonists, often in combination with other CNS depressants. Respiratory depression is a significant concern in these patients. The probability that the unmanageable pediatric patient has been placed into a physical restraint, such as the Pedi-Wrap or papoose board, increases the likelihood of respiratory depression while decreasing the team’s ability to monitor respiration. A rubber dam used to isolate the oral cavity may also be in place, restricting mouth breathing and hindering visualization of oral mucous membranes. The use of a pretracheal stethoscope and pulse oximeter is therefore considered essential whenever parenteral pediatric sedation or more profound oral sedation is employed.

RECORDKEEPING A written record must be prepared for each patient during the administration of sedative or anesthetic drugs. Such records serve several purposes: 1. As a trend plot of vital signs 2. As an aid to the clinician’s memory 3. As documentation of a patient’s response to the administration of drugs and the operative procedure 4. Nonclinically, as a legal document Records maintained for sedative and general anesthetic procedures are essentially identical; however, a basic difference in these records is the frequency and the level of monitoring. Fig. 5.16 illustrates an example of a time-based record used in sedation and general anesthesia.

Sedation Record In the sedation form (see Fig. 5.16) patient identification is presented on the top of the record followed by a summary of the patient’s medical history and current medications. Baseline vital signs, NPO (nothing by mouth) status, and procedure are listed followed by a summation of monitors utilized, operator, assistant, start and stop times, premedications, and IV placements. Intraoperative monitoring and drug administration data are found on the lower half of the chart (Fig. 5.17). Time is noted across the top column, and directly below are spaces for



CHAPTER 5  Monitoring During Sedation

Figure 5.16  Anesthesia record, which may be used for sedation or general anesthesia.

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Figure 5.17  Intraoperative monitoring and drug administration data section.



CHAPTER 5  Monitoring During Sedation

recording vital signs and dosages of drugs administered. The names of all drugs administered, including local anesthetics, are listed, with the milligram dose or flow rate (liters per minute) of gases placed in the appropriate column. At the conclusion of the procedure, the final anesthesia and surgery times of the chart are completed, summarizing the drugs administered (used) and discarded (wasted) and additional comments (located at the bottom of the record). The ADA recommends, minimally, that vital signs be recorded: 1. Preoperatively for baseline comparison 2. Intraoperatively after the administration of any drug 3. Interoperatively every 5 to 15 minutes during treatment (based on depth of sedative/anesthetic) 4. Immediately postoperatively 5. Just before discharge The purpose of the comment section is to provide helpful hints that may improve the quality of subsequent sedation procedures on the same patient. For example, it might be noted that the only readily apparent site for venipuncture was the right antecubital fossa or that midazolam was somewhat ineffective in producing sedation but changing to diazepam markedly helped. The doctor and assistant then sign the form, which is placed into the patient’s permanent dental or medical chart for future reference, if needed. Many monitoring devices are supplied with an automatic printer that provides a chronologic record of vital signs; the reverse side of the monitoring sheet allows for a photocopy of this record to be attached. Because most of the monitor tapes record on thermal-sensitive paper, which fades over time, it is suggested that a photocopy of the tape be made and included on the sedation record. Many states require the use of time-based records, which detail the time that each medication was administered.

General Anesthesia Record Because the patient receiving general anesthesia is unconscious and unable to respond to verbal or physical stimulation, intensified monitoring is an unconditional necessity. As described in the preceding section, the frequency and

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intensity of monitoring are increased as CNS depression increases. Several vital functions (e.g., heart rate and rhythm, respiration, SpO2, temperature, and ETCO2) are monitored continuously, whereas others, including blood pressure, are monitored at intervals of 5 minutes. Each of the small, thin vertical lines is an interval of 5 minutes; the thicker, darker lines represent 15 minutes (see Fig. 5.17). Drug administration is listed chronologically in addition to the performance of specific procedures, such as the start of anesthesia, the start of surgery (i.e., incision made), specific intraoperative procedures, the termination of surgery, and the termination of anesthesia. Examples of completed sedation and general anesthesia records are presented in Fig. 5.18. The anesthesia record also provides an area for monitoring of the patient during the postoperative period in the anesthesia recovery room. The example record (see Fig. 5.17) lists the discharge information at the bottom left. Recordkeeping is an important aid to the doctor in reconstructing events that occurred during a sedative or general anesthetic procedure. Review of records can also provide the doctor with information regarding a patient’s prior response to certain drugs or procedures, possibly alerting the doctor to modify treatment or drug therapy at subsequent appointments. In addition, well-maintained written documentation can greatly assist in a doctor’s defense, should a claim be made against the individual or facility. Because of the potential value of the written sedation or anesthesia record, it is important that these records not be altered after the fact. In addition, it is essential that these records be completed using permanent ink. Should an error or omission be noted after the fact and it becomes necessary to add, change, or delete something from the written record, a single line should be drawn through the error (without obscuring it, which would only increase suspicion) and the correction entered and initialed. If this occurs at a later date, include both the time and date of the correction. The record should remain with the patient’s medical or dental chart as a part of the permanent record.

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Figure 5.18  Completed anesthesia record.



CHAPTER 5  Monitoring During Sedation

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Subcommittee, American Heart Association: Recommendations for blood pressure measurement in humans: an AHA scientific statement from the Council on High Blood Pressure Research Professional and Public Education Subcommittee. J Clin Hypertens (Greenwich) 7(2):102–109, 2005. 16. Cote CJ, Rolf N, Liu LM, et al: A single-blind study of combined pulse oximetry and capnography in children. Anesthesiology 74(6):980–987, 1991. 17. Domino KB, Lee LA: The Closed Claims Project: Has it influenced anesthetic practice and outcome? Anesthesiol Clin North America 20(3):485–501, 2002. 18. Luks AM, Swenson ER: Pulse oximetry at high altitude. High Alt Med Biol 12(2):109–119, 2011. 19. Severinghaus JW, Kelleher JF: Recent developments in pulse oximetry. Anesthesiology 76(6):1018–1038, 1992. 20. Barclays Official California Code of Regulations. Title 16. Professional and Vocational Regulations. Division 10. Dental Board of California. Chapter 2. Dentists. Article 5.5. Oral Conscious Sedation. Available at: www.dbc.ca.gov. (Accessed 14 April 2016). 21. Shah N, Ragaswamy HB, Govindugari K, Estanol L: Performance of three new-generation pulse oximeters during motion and low perfusion in volunteers. J Clin Anesth 24(5):385–391, 2012. 22. Vascello LA, Bowe EA: A case for capnographic monitoring as a standard of care. J Oral Maxillofac Surg 57(11):1342–1347, 1999. 23. ADA News: Comments sought on proposed sedation, anesthesia guideline revisions. June 16, 2014. Available at: http://www.ada.org/en/publications/ada-news/2014-archive/ june/comments-sought-on-proposed-sedation-anesthesia -guideline-revisions. (Accessed 14 April 2016). 24. Stanski DR, Shafer SL: Measuring depth of anesthesia. In Miller RD, Fleisher LA, Johns RA, et al, editors: Miller’s anesthesia, ed 6, London, 2005, Churchill Livingstone. 25. Kissin I: Depth of anesthesia and bispectral index monitoring. Anesth Analg 90(5):1114–1117, 2002. 26. National Institute for Healthcare Excellence: Depth of anaesthesia monitors – Bispectral Index (BIS), E-Entropy and Narcotrend-Compact M. NICE diagnostics guidance 6. Issued November 2012. Available at: www.nice.org.uk/dg6. (Accessed 15 April 2016). 27. Glass PS: Anesthetic drug interactions: an insight into general anesthesia—its mechanisms and dosing strategies. Anesthesiology 88(1):5–6, 1998. 28. Eichhorn JH, Cooper JB, Cullen DJ, et al: Standards for patient monitoring during anesthesia: Harvard Medical School. JAMA 256(8):1017–1020, 1986. 29. Sollai S, Dani C, Berti E, et al: Performance of a non-contact infrared thermometer in healthy newborns. BMJ Open 3:e008695, 2016. 30. Kurz A: Thermoregulation in anesthesia and intensive care medicine. Best Pract Res Clin Anaesthesiol 22(4):vii–viii, 2008.