Emergency Management

Abstract

The pediatric dentist commonly provides minimal and moderate sedation in the office-based setting. The proper management of sedation emergencies is critical to ensure the safety of the children for whom we care. The vast majority of sedation-related emergencies occur when intended moderate sedation progresses to deep sedation or general anesthesia. Due the variability in both pharmacodynamic and pharmacokinetic sedative drug effects, even the “standard dose” may turn out to be an overdose in a susceptible patient. Airway complications are the most likely sedation-related complications in healthy children. Airway obstruction from the tongue, a foreign body, laryngospasm, and bronchospasm are the most probable diagnoses. The ability to provide positive pressure oxygen, with or without an oropharyngeal airway, is the most critical skill needed to rescue children from sedation-related emergencies aside from recognition that a problem has actually occurred. An algorithm for managing these airway emergencies is provided.

The pediatric dentist provides invasive procedures to very young children on a regular basis that are either too painful or extensive to be accomplished with local anesthesia alone even with the addition of minimal sedation. To this group of children, we must also add those who are uncooperative or have special needs that simply cannot be managed without some form of advanced pain and anxiety control. Many of these procedures could be accomplished in the operating room with general anesthesia if insurance companies acknowledged that these “dental” procedures are in some cases more invasive, or at least similar in invasiveness, to many “medical” procedures and thus extended their benefits accordingly. In addition to this challenge in our healthcare system is the widespread lack of training to competency of the technique of intravenously administered sedation in most pediatric dental residencies. Therefore, orally administered sedatives to minimal or moderate levels of sedation, with or without the addition of nitrous oxide/oxygen, has become the common form of sedation in the pediatric dental practice.

The majority of pediatric patients administered oral sedation in dental offices are American Society of Anesthesiologists (ASA) Physical Status I. For this group of children, the most common adverse event is related to airway complications. Young children are particularly prone to rapid desaturation secondary to airway compromise due to anatomic and physiologic factors including:

• Decreased number of alveoli until age 8 [1]

• Immature pulmonary vasculature surrounding the alveoli [2]

• Oxygen consumption 1.5–2 times that of the adult [3]

• Decreased functional residual capacity [4]

When reviewing retrospective data on pediatric sedative emergencies [5–7], it is clear that airway complications leading to hypoxemia with subsequent cardiac complications were the most frequently encountered emergencies regardless of provider type or venue. Although valid conclusions are difficult, if not impossible, to draw from retrospective studies, poor resuscitation and delay in activating emergency medical services (EMS) for support seem to be two factors in poor outcomes, particularly in the dental setting.

The preoperative identification of the pediatric patient at risk for airway complications should be a priority for every dentist contemplating sedation for his/her patient. Although the Mallampati scoring system is widely used as an airway assessment tool, the score is designed to predict difficult intubation, not mask ventilation. And it is the ability to mask ventilate a patient who is apneic, hypoventilating, or faced with soft tissue or other airway obstruction that will dictate successful resuscitation. Other prognosticators that might be of greater value in predicating the potential of difficult airway management include a detailed history of the following: presence of snoring at night, diagnosed obstructive sleep apnea, history of nocturnal enuresis, and possibly behavioral disorders that might, in part, be related to disordered nocturnal breathing. A focused physical examination observing the size of the tongue in relation to the mandibular vault, tonsil size, weight, mobility of the neck and TMJ adds important information. In children with a history of bronchospastic disease or recent URI, auscultation of the chest is important to detect the presence of preoperative wheezing or crackles.

A Guided Risk Assessment (GRA) to preoperatively identify patients at risk for sedation-related complications was created by Hoffman et al., in 2002 [8]. It important to note that five of the 12 (designated by **) factors studied were related to airway issues:

• 1. Snoring, stridor, or sleep apnea**

• 2. Craniofacial malformation**

• 3. History of airway difficulty**

• 4. Vomiting, bowel obstruction

• 5. Gastroesophageal reflux

• 6. Pneumonia or oxygen requirement**

• 7. Reactive airway disease**

• 8. Hypovolemia, cardiac disease

• 9. Sepsis

• 10. Altered mental state

• 11. History of sedation failure

• 12. Inadequate NPO time

The use of this GRA was found to improve outcomes in pediatric sedation. Other factors that appeared to contribute to complications included sedation utilizing multiple drugs as well as the use of chloral hydrate, whether part of a multidrug technique or not.

While the pediatric dentist should attempt to identify patients at an increased risk and prepare for specific sedation-related emergencies, he or she may also need to manage non-sedative-related medical emergencies that may be encountered in the dental office. Common medical emergencies that are most likely to occur in the pediatric dental office, such as an asthma attack, allergy/anaphylaxis, or seizures, will not be covered in this chapter as they are not directly sedation-related emergencies. Certainly, these emergencies can occur as part of a sedation treatment and, when appropriate, will be discussed below.

Since airway obstruction or hypoventilation are clearly the primary initiating events in most dental office-based sedation emergencies, this chapter will focus on the recognition and management of various airway-related sedation emergencies. The American Academy of Pediatric Dentistry (AAPD) [9], as well as the American Dental Association [10], definition of moderate sedation includes the following statement: “No interventions are required to maintain a patent airway.” This includes the most basic of interventions – the head tilt/jaw thrust maneuver used to open the airway in the patient experiencing the most common cause of sedation-related airway obstruction: the tongue moving posteriorly and fully or partially blocking the upper airway. Despite this type of airway obstruction in the adult patient, a response to a verbal command, such as “Mr. Smith, take a deep breath,” might be sufficient to reinitiate breathing. The verbal command could be combined by “light tactile stimulation,” such as gently shaking the shoulder. According to standard definitions, this patient would still meet the criteria of moderate sedation if these maneuvers reinitiated voluntary breathing and the patient was easily arousable [5, 6]. If, however, the head tilt and/or jaw thrust were required to eliminate airway obstruction, a state of deep sedation would be diagnosed. When the only response to a painful stimulus is reflex withdrawal or a repeated painful stimulus is necessary to arouse a sedated child, he/she is in deep sedation or general anesthesia; this must be recognized immediately, monitored and managed accordingly, and rescued back to a moderate level of sedation.

It must be appreciated that if a dentist is only educationally qualified and permitted to administer moderate sedation, any deviation into deep sedation and general anesthesia is fraught with the possibility of misadventure. The focus of the pediatric dentist is always to maintain the child in moderate sedation, and going further down the sedation/anesthesia continuum is likely the cause of mortality and morbidity in pediatric sedation. Moderate sedation-trained pediatric dentists cannot guarantee that all patients will be able to complete their treatment plans. There will be some unsuccessful sedations, but this should be viewed positively since the dangers of deep sedation could result in more serious consequences than incomplete dental treatment.

What are the dangers of an unqualified practitioner allowing their patient to enter a state of deep sedation? As a child becomes more deeply sedated, these respiratory issues may arise:

• 1. Progressive loss of airway due to increased loss of airway muscle tone. Almost all common pediatric sedation drugs depress ventilation and diminish muscle tone. Although a moderately sedated patient is the goal, a reduction in airway muscle tone can lead to collapse of upper airway structures leading to airway obstruction. With oral sedative drugs, the peak effect is not predictable or consistent, and drugs administered orally cannot be titrated to effect as they can be via the intravenous route. Hence, initial signs of airway obstruction may not be true indications of the impending airway collapse as peak drug effects may not have fully taken place. As greater airway muscle relaxation occurs, airway obstruction may no longer be overcome with simple head tilt and/or jaw thrust. Other more advanced airway rescue techniques, not normally practiced routinely by moderate sedation providers, may need to be emergently employed.

• 2. Laryngospasm. This is an acute airway emergency wherein a normal reflex – involuntary closure of the vocal cords to prevent aspiration – becomes hyperactive and life threatening in the deeply sedated patient. In the conscious patient, when a small amount of water or other material irritates the vocal cords, the body responds by coughing vigorously to clear the airway and forcing air into the lungs during brief inspirations. The vocal cords close partially to protect the delicate airway mucosa. This episode is colloquially referred to as “something went down the wrong pipe.” In the deeply sedated patient with this type of stimulus, the vocal cords may close, or spasm, completely, leading to severe hypoxemia and hypercarbia and is termed a “laryngospasm.” Being trained to immediately diagnosis and respond to this emergency situation is one of the most important aspects in the training of dental deep sedation and general anesthesia providers. A laryngospasm may be overcome with the gentle application of positive pressure ventilation via a bag/valve/mask or in more resistant cases with a short-acting skeletal muscle relaxant, which should only be administered by those with advanced training.

• 3. Aspiration. Although not a common complication, regurgitation of gastric contents can occur in patients who lose their protective airway reflexes during deep sedation. Patients are at increased risk when emetogenic agents, such as opioids and chloral hydrate, are used. The aspiration of gastric contents is a major medical/sedative emergency and the combination of bronchospasm and physical obstruction of the airway can be life threatening.

All of the airway complications described above require advanced clinical and didactic training. Advanced Cardiac Life Support (ACLS) and Pediatric Advanced Life Support (PALS) are no substitutes for intensive hands-on emergency management taught to competency. When an airway emergency does occur, children desaturate quickly, and thus continual observation and monitoring of the child during sedation is mandatory to rapidly detect early signs of dropping oxygen saturation or poor ventilation before an airway event becomes critical.

In the following sections, emergency equipment and drugs will be reviewed as well as a suggested algorithm for initially managing these airway complications. The presence of equipment and drugs pales in significance to a well-functioning sedative dental team where all members have value and where communication skills are practiced and honed. Constant review and updating of emergency scenarios is a must to keep the team cohesive and prepared. The introduction of pediatric emergency simulation courses using high-fidelity human simulators combined with the tenets of Crisis Resource Management has resulted in educational programs for the entire pediatric dental team as offered by the AAPD, American Society of Dentist Anesthesiologists, American Dental Society of Anesthesiology, and possibly other groups.

Equipment and Drugs

The apparatus to deliver oxygen under positive pressure ventilation (PPV) is the single most important item of emergency equipment for overcoming apnea and soft tissue airway obstruction due to unintended deep levels of sedation. Besides an oxygen source, a bag/valve/mask with a reservoir combined with a full-face mask is required. There are many brands to choose from, but importantly, as with any emergency equipment in the pediatric dental office, pediatric- and adult-sized versions are required. The adult size is needed for larger adolescents and parents should a medical emergency occur. Emergency oxygen from a portable “E” cylinder when full (2000 psi on the pressure gauge) contains approximately 660 l of oxygen that can deliver approximately 60 min of oxygen at a flow rate of 10 l/min. Besides the portable “E” cylinder, oxygen can also be accessed via the nitrous oxide/oxygen unit with the appropriate adaptors. A portable E cylinder is still required should a medical emergency occur outside the operatory. A Robert Shaw demand valve that can deliver up to 50 psi oxygen is not advocated for PPV in children for moderate sedation trained dentists for its use can possibly result in barotrauma and pneumothorax.

Oropharyngeal airways (OPAs) in various sizes are important in overcoming soft tissue obstruction in an unconscious child. See Fig. 13.1a, b for proper positioning of the OPA. Placement of the OPA can be performed by depressing the tongue with a tongue blade and inserting the airway with the curve pointing caudal or by inserting it with the curve cephalad and turning it 180° when fully inserted. This skill should be practiced in dedicated simulation courses and/or basic life support, PALS, or ACLS courses. Nasopharyngeal airways may also be used, but the risk of nasal bleeding during an airway emergency may limit their utility. See Fig. 13.2.

Fig. 13.1

(a, b) Oropharyngeal airways, sizing and in proper position

Fig. 13.2

Nasopharyngeal airways

Various supraglottic airways can also be utilized in unconscious patients as advanced airway adjuncts and are indicated when BVM and the insertion of an oropharyngeal airway do not overcome soft tissue airway obstruction or the pressure needed to generate an adequate tidal volume is too high, such that gastric insufflation is likely. A supraglottic airway is generally easy to insert and provides a conduit for air directly to the glottic area. There are many to choose from and one commonly used type is the laryngeal mask of which various brands and designs are available. Of the laryngeal masks, the i-Gel brand does not require cuff inflation, has venting for gastric air, and does not fold at the tip. Therefore, the i-Gel may reduce tasks and ease placement such that PPV can be more rapidly provided in an emergency. Placement is generally uncomplicated, but repeated training in its use is required (Fig. 13.3). Another supraglottic airway, the King LTD, is one version of a supraglottic airway that enters the esophagus with inflatable cuffs that seal the esophagus and oropharynx. Fenestrations between the cuffs allow an attached BVM to provide ventilation to the glottis (Fig. 13.4). Although endotracheal intubation is the gold standard for securing the airway, endotracheal tube insertion is generally not in the skill set of the pediatric dentist (Fig. 13.5).

Fig. 13.3

(a–d) i-Gel laryngeal mask top, bottom and side views and laryngeal mask in position

Fig. 13.4

(a) King LTD and (b) King LTD in position

Fig. 13.5

Endotracheal tube with stylet

The AAPD recommends drugs and equipment that should be available in pediatric dental offices for both medical- and sedation-related emergencies. Significant latitude is allowed for individual practitioners, however. Tables 13.1, 13.2, and 13.3 list recommended AAPD medical emergency drugs as well as sedation emergency drugs and equipment listed in the 2007 Joint American Academy of Pediatrics (AAP)/AAPD Guideline for Monitoring and Management of Pediatric Patients During and After Sedation for Diagnostic and Therapeutic Procedures [9] that can be modified based on provider training, skill, and practice. According to the Joint Guidelines, “The choice of emergency equipment may vary according to individual or procedural needs.” Therefore, Tables 13.4, 13.5, and 13.6 list what the author considers a focused and practical medical and sedation emergency kit for the pediatric dentist providing office-based oral moderate sedation based on current training standards. All of these drugs and devices may not be discussed in this chapter so the pediatric dentist is encouraged to review these tables carefully.

Table 13.1 AAPD recommended medical emergency drugs

Table 13.2 AAP/AAPD drugs that may be needed to rescue a sedated patient

Table 13.3 AAP/AAPD equipment that may be needed to rescue a sedated patient

Table 13.4 Author-recommended medical emergency drugs

Table 13.5 Author-recommended drugs that may be needed to rescue a sedated patient

Table 13.6 Author-recommended equipment that may be needed to rescue a sedated patient

A number of basic and critical emergency drugs are required for the pediatric dental office setting in addition to oxygen as listed above. Epinephrine is a critical emergency drug for a number of emergencies, including bronchospasm, anaphylactic shock, and bradycardia secondary to severe hypoxia during sedation. The pediatric dose of epinephrine is 0.01 mg/kg to a maximum of 0.3 mg intramuscularly (IM). It can be delivered via an auto-injector (e.g., EpiPen), and they are available in adult (0.3 mg/dose) and pediatric doses (0.15 mg/dose). Although the FDA inserts suggest the EpiPen be used for patients over 30 kg and the EpiPen Jr. for patients under 30 kg for self-use, in the monitored environment of the dental office where a trained medical provider is present, the author’s recommendation is to use the EpiPen for patients over 20 kg and the EpiPen Jr. for patients less than 20 kg. The author’s rationale is based on the premise that epinephrine will only be used in the dental office if a truly life-threatening emergency is present on generally healthy patients. For the pediatric patient with cardiovascular disease, the lower dosing regimen can be used (but these children are unlikely to be sedated in a dental office). The alternative formulation for pediatric IM administration is 1:10,000 epinephrine in preloaded syringes. Each 1 ml of solution contains 0.1 mg of epinephrine. Hence, for every 10 mg of body weight, one ml of solution would be administered IM to a maximum individual dose of 0.3 mg (e.g., 10 kg child gets 1 ml; 25 kg child gets 2.5 ml; 40 kg child gets 3 ml). Ampules or vials of epinephrine 1:1,000, or 1 mg/ml, may also be used but require more steps and calculations to obtain the desired dosage and may result in delay in administration.

For grand mal seizures that do not terminate in minutes, midazolam 5 mg/ml solution IM can be administered. The dose is 0.2 mg/kg to a maximum of 10 mg. This is preferable to diazepam which has erratic IM absorption. Intranasal (IN) midazolam can be considered if special mucosal atomizer devices are available. The IN dose is the same with a maximum of 1 ml or 5 mg per nostril. Onset is faster than IM but sedative level may also be increased. Parents or other caregivers may have other medications to manage seizures, such as rectal diazepam. Discussion regarding seizure management at home prior to dental treatment of the epileptic patient is advisable, especially if seizures persist despite optimal medical therapy.

The opioid reversal agent, naloxone 0.4 mg/ml (Narcan), is required if opioids are part of the sedation regimen. The pediatric dose in sedation emergencies involving apnea or hypoventilation is 0.1 mg/kg to a maximum of 2 mg IM. Higher doses will not result in harm, however, in the setting of pediatric dental sedation in non-opioid-dependent children. Hence, the recommendation for the pediatric dentist is to administer the full 2 mg (5 ml) to all patients who require opioid reversal. It should be appreciated that opioid effects may outlast naloxone reversal and re-sedation and/or respiratory depression may recur. Regardless, for the pediatric dentist, if opioid reversal is required, EMS should have been called and patient transport to the hospital would be appropriate. Since 5 ml of solution is required, it is appropriate to have one 10 ml vial of 0.4 mg/ml naloxone.

The benzodiazepine antagonist flumazenil 0.1 mg/ml (Romazicon) in 5 ml vials is required if benzodiazepines are part of the intended sedation regimen no matter the route of administration. Flumazenil is FDA approved for IV administration only. IM dosing regimens are not evidenced based. Initial IV dosing is 0.01 mg/kg to a maximum of 0.2 mg/dose. This is for initial dosing only and it is highly likely multiple IV doses will be required in the setting of benzodiazepine overdose. Clearly, higher doses will be required IM due to slower absorption than IV administration. Although without any scientific basis, the author would recommend a practical approach of initial dosing of 10 ml, or 1 mg, administered in two IM injections of 5 ml each. In benzodiazepine overdose, this will only aid resuscitation without harming the patient, particularly if EMS is delayed. Again, if reversal agents are needed, EMS should already have been contacted. Four 5 ml vials of flumazenil are recommended as the minimum that should be available.

When discussing IM administration, the standard medical emergency access sites for intramuscular drug delivery, the deltoid and vastus lateralis muscles, are appropriate for sedative emergency drugs. For smaller children, only a maximum of 3 ml should be used in the deltoid. Larger volumes should be administered in the lateral vastus. Whether the deltoid or the vastus is utilized, injection with a 22G, 1” needle can take place through thin clothing such as a shirt or jeans. Very thick clothing such as thick sweatshirts may pose an injection obstacle. Although the tongue can be used for IM administration, injection in this site frequently leads to bleeding which is undesirable in an emergency. Likewise, the sublingual region may bleed or the lingual artery may be encountered which can lead to rapid sublingual swelling. Although these sites can be used, their limitations should be appreciated. In addition, the volume of the required injection makes these sites impractical.

Intraosseous (IO) access, as taught in PALS (http://www.heart.org/HEARTORG/CPRAndECC/HealthcareProviders/Pediatrics/Pediatric-Advanced-Life-Support-PALS_UCM_303705_Article.jsp), has also been advocated for the pediatric dentist for emergency drug administration. If considered, this will require the pediatric dentist having (1) up-to-date clinical experience in obtaining IO access, (2) all the intravenous equipment and IV fluid available, and (3) a trained staff who can assist in the procedure and understanding intraosseous dosing (same as for IV). If all of these criteria are met, then this may be an alternative to IM or emergent IV administration. This author’s concern is that obtaining IO access takes the dentist away from his/her primary objective in a serious airway emergency: BVM ventilation with 100 % oxygen. If other dental/medical personnel are available for IO access and the above requirements are met, certainly, IO access can be considered for reversal agents. Epinephrine should always be administered IM unless the patient does not have a perfusing rhythm or the dentist has advanced general anesthesia training and PALS certification.

Every office should rehearse procuring outside emergency assistance. Only the dentist should activate this system by communication to an appropriate staff member who should make the call. Practicing exactly what information should be transmitted and what type of help to request, preferably paramedic-trained emergency medical technicians (EMT-Ps), is needed.

As critical as it is to have all the necessary equipment and drugs in the dental office, if they are not immediately available, valuable time will be lost managing a sedation-related emergency. All of the appropriate emergency equipment and drugs should be immediately available in the operatory where sedation is taking place . This one step can make the difference in appropriately and rapidly responding to an emergency. Utilizing a checklist prior to a procedure, thus assuring that all contingencies have been addressed, as well as working together as a team is important in obtaining a good outcome in a sedation-related emergency. Every team member should have an assigned role in the event of an emergency. Staff should be cross-trained in their roles in case of a missing team member. A specific team member should be assigned to assure that emergency equipment is ready (e.g., that there is sufficient pressure in the oxygen tank) and that emergency drugs are in place and expiration dates have been verified. Cognitive aids such as algorithms and drug doses should be immediately available for consultation. Every second counts when addressing the emergency needs of a sedated child, and time is not on our side during pediatric airway emergencies. The more rapidly and effectively we respond, the greater the likelihood that there will be a successful resuscitation.

Monitoring

This topic is thoroughly discussed in Chap. 7. Monitoring derives from the Latin root meaning “to warn,” and that is exactly its role for the pediatric dentist: to anticipate and respond to sedative emergencies focusing on ventilation and oxygenation whether administering minimal/moderate or deep sedation. Monitoring of ventilation ranges from observing chest excursions and extends to the use of pretracheal/cordial stethoscope and capnography. Combining monitors is more than merely complementary but adds great value. Oxygenation is monitored by the pulse oximeter as well as observation of skin and mucous membrane color.

If the sedated child is crying or otherwise interacting during moderate sedation in which a pretracheal stethoscope is being used, the pediatric dentist need not have the earpiece stethoscope or speakers in place as clearly the patient is in a level of minimal or moderate sedation and the level of consciousness is obvious.

Causes of Oxygen Desaturation

Oxygen desaturation can occur during pediatric oral sedation and is most often attributed to respiratory depression or airway obstruction at various levels of the airway. Table 13.7 lists the differential diagnosis of common sedative airway emergencies.

Table 13.7 Differential diagnosis of common airway emergencies in pediatric oral moderate sedation

The most common airway complication during pediatric sedation is seen when the upper airway is obstructed by the tongue due to the effects of sedating drugs causing skeletal muscle relaxation of the tongue and pharyngeal structures. Commonly, the head tilt and/or jaw thrust maneuver will correct this obstruction, but even when correctly performed, this maneuver may not adequately displace the tongue off the posterior pharyngeal wall. The presence of a rubber dam, particularly if placed on the entire mandibular arch, may posteriorly displace the tongue and block the airway. The dam may need to be repositioned or removed and more carefully placed. Foreign body obstruction can occur from many objects of dental origin such as a gauze pack behind the tongue, cotton rolls, crowns, or extracted teeth. Remember that blind finger sweeps are not part of the American Heart Association algorithm for lost foreign objects in the hypopharynx, if this situation is encountered. Tying a piece of dental floss to the gauze throat screen with the end of the floss taped outside the mouth facilitates removal and prevents aspiration.

Obstruction can also occur lower in the upper airway at the level of the vocal cords. This condition is termed laryngospasm and was discussed previously. Persistent laryngospasm is a condition where the airway reflexes are hyperactive and stimulation results in sustained vocal cord closure with inability to ventilate. By definition, the patient is in a level of deep sedation. In minimal and moderate sedation as well as general anesthesia, laryngospasm does not occur.

Finally, there can be obstruction in the lower airway either by the acute constriction of the small muscles of the tracheobronchial tree (bronchospasm) or the presence of a foreign body (e.g., tooth, crown, gauze, particulate vomitus) blocking the airway. Silent aspiration of gastric contents can occur when a patient regurgitates and then aspirates gastric contents without signs of choking or coughing. This can occur whenever laryngeal reflexes are diminished due to central nervous depressants and commonly leads to bronchospasm.

Emergency Airway Algorithm

Although there are many possible etiologies of decreased oxygenation, in ASA I and well-controlled ASA II patients undergoing office-based pediatric oral sedation, conditions other than airway obstruction are very rare, and in any case, primary management would still follow the standard algorithm below.

Assuring adequate respiratory exchange and acting immediately to address ventilatory issues are the most important aspects in the care of sedated children. Immediate diagnosis of impending hypoxia and hypercarbia is first detected by close observation of the child by the team and is confirmed by appropriate respiratory monitors and auscultation. The immediate introduction of airway rescue maneuvers, discontinuation of nitrous oxide, use of basic and advanced airway rescue equipment, and possible pharmacologic reversal of sedative drugs must take place in the framework of a logical and practiced algorithm.

Supplemental oxygen should be utilized during all pediatric dental sedations, whether by nasal hood, with or without nitrous oxide, or via nasal cannula. This will ensure that the child will have an oxygen reserve to increase the time to hypoxia during an airway emergency.

Diagnosis of emergent airway issues is based on diminished breath sounds, lack or decrease in end tidal CO₂ (ETCO₂) measurements, decreasing hemoglobin saturation of oxygen by pulse oximetry (SpO₂) readings, and a progressive bradycardia. Bradycardia during a respiratory emergency is an ominous sign and it indicates an impending cardiac arrest. The two most likely causes of these warning signs are hypoventilation secondary to excessive sedative drug effect or upper airway obstruction by the tongue and tissues in the hypopharynx. Both will result in diminished breath sounds, lack of ETCO₂, and decreasing SpO₂ levels. The initial response should be the application of the head tilt, and if needed, jaw thrust, maneuver. If breath sounds and/or ETCO₂ waveforms increase, the cause can be assumed to be airway obstruction secondary to the soft tissue obstruction. It must be appreciated that this situation could also indicate a level of deep sedation, for during moderate sedation, by definition the airway needs no interventions. If the child is unresponsive, decreasing nitrous oxide, considering reversal agents, and meticulously monitoring ventilation and oxygenation are required.

If, however, a simple head tilt and jaw thrust does not improve ventilation, the dentist should remove anything blocking visualization of chest excursions such as a dental bib or loose papoose board straps. As needed, upper garments can be pushed up to the neck to see abdominal/thoracic movements. Objects of dental origin should be removed from the mouth. This is a major respiratory emergency. If ventilatory effort is being made against an anatomical airway obstruction, a paradoxical breathing pattern will occur. As opposed to regular abdominal movement present in sedated patients who are ventilating normally, vigorous abdominal movement followed by higher accessory airway muscle activity will manifest itself as a “rocking horse” or paradoxical breathing pattern. This rocking horse breathing pattern is characterized by alternating rise and fall in the chest and stomach areas, respectively, with no airway movement. This breathing pattern diagnoses airway obstruction as opposed to hypoventilation or apnea in which regular abdominal breathing is shallow or absent.

If hypoventilation is suspected, all material is removed from the mouth if not already accomplished including the rubber dam, the airway is opened again via the head tilt, and as needed, the jaw thrust maneuver is performed. Stimulating the patient with a repeated trapezius muscle squeeze, sternal rub, or deep mandibular angle pressure (i.e., strong anteromedially directed deep digital pressure behind the ramus of the mandible in the “laryngospasm notch” located just anterior to the mastoid bone) will often increase ventilation. If ventilation does not improve, positive pressure oxygen will need to be instituted. At this point, there will likely be a decreased SpO₂. If initial attempts at PPV do not result in audible breath sounds or increasing ETCO₂, but most importantly adequate chest rise, an oropharyngeal airway should be inserted immediately and PPV reinstated. If lack or severely diminished ventilation was due to serious airway obstruction secondary to the tongue despite head tilt/jaw thrust, breathing should resume or the patient should be able to be ventilated or assisted via PPV. In the face of an unresponsive, obstructed patient necessitating the insertion of an oropharyngeal airway, it is evident that this child is either deeply sedated or in general anesthesia. If these actions result in good ventilation via PPV and a return to normal SpO2, the dentist should discontinue dental treatment and continue to support ventilation providing rescue breathing as taught in BLS. The patient is in respiratory arrest.

At this point, the dentist has three options:

• (1) Continue to assist ventilation as needed until the child returns to a level of minimal to moderate sedation, and then resume treatment after assuring responsiveness and acceptable vital signs are present.

• (2) Terminate the procedure and continue to assist ventilation as needed until the patient returns to a level of minimal sedation and discharge the patient only when appropriate criteria are met. Reschedule for general anesthesia or another oral sedation procedure with different drug dosing or a different drug regimen.

• (3) Terminate the procedures and administer appropriate IM reversal agents if benzodiazepines and/or opioids have been administered, monitor the patient for a minimum of 2 hours, and discharge when criteria are met.

If despite opening the airway with head tilt/jaw thrust maneuvers, PPV with a BVM, insertion of an oropharyngeal airway, and more attempts with PPV via BVM, ventilation is still impossible, then a life-threatening emergency is underway. EMS must be activated as soon as possible, but they will not arrive in time to rescue this patient without the dentist and staff continuing resuscitative efforts until EMS arrives. The obstruction may be below the tongue and possibly at the level of the vocal cords – laryngospasm is most likely the diagnosis assuming there is no obvious foreign body. It should be appreciated that if silent regurgitation of particulate gastric contents occurred, a foreign body may be present but not recognized. The hypopharynx should be suctioned with a Yankauer suction tip. The application of gentle and continuous PPV should continue in an attempt to break laryngospasm. If laryngospasm is suspected, the patient is by definition in a state of deep sedation. At late stages, hypoxia and unconsciousness will also break laryngospasm with resultant muscle relaxation occurring including that of the vocal cords. The SpO2 may, however, be very low at this point and the patient may be frankly cyanotic and becoming bradycardic. Continued overzealous PPV may lead to gastric insufflation with increased risk of regurgitation. It is at this point that the insertion of a supraglottic airway should be considered. The use of succinylcholine, a skeletal depolarizing muscle relaxant, is not recommended for those moderate sedation providers who are not trained to manage the paralyzed patient.

If continued attempts at PPV are still ineffective, hypoxemia will progress and the patient will begin to develop diminished heart rate and, eventually, frank bradycardia. Always remember that this is an airway emergency that has now degenerated into a cardiac one. Although IM epinephrine, 0.01 mg/kg up to 0.3 mg, should now be administered to treat hypoxemia-induced bradycardia and treat possible bronchospasm, it is the lack of oxygen and retention of carbon dioxide that is the root of the problem, and without relief, the patient will suffer severe neurologic morbidity and mortality. However, epinephrine will help preserve circulation, and treat bronchospasm if this is the cause of airway obstruction, for a short time while airway control maneuvers continue.

Efforts at PPV must continue until EMS arrives and assists or takes over rescue efforts. If at any point breath sounds resume, chest excursions are noted, and/or ETCO₂ increases, it should be appreciated that the SpO₂ will increase very gradually, particularly if it is very low. There is a significant lag time in the pulse oximeter registering resumption of adequate ventilation with 100 % oxygen. More importantly, all delivered oxygen is being distributed to vital organs and none is attaching to hemoglobin until tissue oxygenation is adequate. It may take several minutes for oxygen saturation to return to normal in this scenario.

A summary of this algorithm is presented in Fig. 13.6.

Fig. 13.6

Emergency airway algorithm for pediatric dental oral sedation providers (without IV capability) (BVM bag/valve/mask, IM intramuscular, Epi epinephrine) Note: BVM 10 l/m with 100 % O₂

Prior to EMS arrival, the dentist should dispatch a predetermined staff member to talk to the parent/guardian and inform them that there is a complication which the team is managing. EMS has been called as a precaution. The dentist should always stay with the patient, manage the airway, and travel with EMS personnel, if possible, or follow them to the hospital. Once the patient has been admitted to the emergency department (ED) and the details of the case have been discussed with ED staff, the dentist should meet with the parents to discuss the events.

Once the dentist has returned to the dental office after the ED, the dentist should make detailed notes or write a narrative as to the events that occurred as soon as possible. The sedation record should be completed and all available information secured, such as the monitor printout. If the dentist feels it is appropriate, he/she should invite all staff members involved to do the same. The case should be discussed and the feelings and impressions of all staff members should be shared, if not immediately, soon thereafter. All policies and procedures should be reviewed, and if any changes in protocol seem appropriate, they should be instituted. Appropriate authorities and professional liability insurance providers must be notified.

Conclusion

Serious airway emergencies almost always occur when intended pediatric oral moderate sedation progresses to unintended deep sedation or general anesthesia. With standard dosing regimens, this is unlikely to occur. Of course, the pharmacokinetics and pharmacodynamics of sedative drugs are variable and there are always outlier patients for whom the “standard dose” is, in effect, an overdose that cannot be predicted. Having proscribed emergency drugs and equipment immediately available in the operatory where sedation is taking place can make the difference between a good outcome and an unacceptable one. Time is of the essence. Practicing emergency management on a regular basis with all staff, including new staff members, helps keep the entire team in a state of readiness. Alerting EMS in a timely manner when ventilation is not possible despite a properly placed oropharyngeal airway and attempts at PPV helps ensure that help is on the way. When proper guidelines, regulations, patient selection, and monitoring standards are followed, adverse events are very rare. However, they continue to occur, and all sedation providers must maintain constant vigilance and be prepared to manage acute emergency situations to ensure the health and well-being of these children who have entrusted us with their lives.