© Springer-Verlag Berlin Heidelberg 2015
Stephen Wilson (ed.)Oral Sedation for Dental Procedures in Children10.1007/978-3-662-46626-1_14
14. Emergency Scenarios
(1)
General Anesthesia Services, 407 Geddington, Shavano Park, TX 78249, USA
Abstract
A medical emergency is an unanticipated complication that usually requires quick, focused, calm action to resolve a potentially life-threatening situation. The intent of this chapter is to present emergency scenarios focusing on simplified and logical process of managing the crisis in the dental office. We recommend that a written policy of emergency procedures be generated and discussed on a routine basis with the staff. Emergency protocols should be practiced a minimum of four times per year. The goal of managing an emergency should be to quickly stabilize the patient. To properly handle emergencies in the office setting, the dentist and key members of the team should review emergency protocols, identify in advance the resources and limitations of the practice, and take appropriate actions to correct or eliminate those limitations.
Keywords
Oral sedationCompromised airwayRespiratory depressionAsthmaReactive airwayAllergic reactionEpiPenLocal anesthetic toxicitySyncopeLocal anesthetic toxicityPulse oximetryDesaturationYankauerAnaphylaxis
Emergencies
A medical emergency is an unanticipated complication that usually requires quick, focused, calm action to resolve a potentially life-threatening situation. The intent of this chapter is to present emergency scenarios focusing on simplified and logical process of managing the crisis in the dental office.
We recommend that a written policy of emergency procedures be generated and discussed on a routine basis with the staff. Emergency protocols should be practiced a minimum of four times per year. The goal of managing an emergency should be to quickly stabilize the patient.
To properly handle emergencies in the office setting, the dentist and key members of the team should review emergency protocols, identify in advance the resources and limitations of the practice, and take appropriate actions to correct or eliminate those limitations. Critical management of emergencies most likely will require quick, focused action by the dental office team. If resolution of the complication cannot be rapidly and satisfactorily addressed, calling paramedics to the office is the next key step while continually assisting the patient using basic life support techniques. Transfer to an acute care facility where critical care staff is better suited to manage the acute and long-term aspects of the complication is usually indicated once paramedics are called to the office [1].
Although complications in the delivery of sedation for dental procedures are rare, emergency situations can occur that make it mandatory for certain types of equipment and medications to be readily available. An emergency cart should contain the necessary medications and equipment to resuscitate a non-breathing patient and address other conditions such as an allergic reaction, vomiting, hypoglycemia, and syncope [1].
It is highly likely that 99 % of medical emergencies that may occur in a pediatric office setting can be managed using three basic interventions. A thorough understanding of each will become significant in being prepared and confident when a medical emergency arises.
The first and most important intervention in almost every situation is the delivery of oxygen. The brain, without oxygen, suffers irreparable damage within 4–6 min. Death occurs within about 8 min. In each of the emergency scenarios that follow, oxygen and its efficient delivery will be paramount to rescuing a patient in virtually every emergency situation.
The second intervention is careful attention to patient positioning to facilitate airway patency. Favorable head positioning for dental procedures may not be best for ensuring airway patency. Many times, the simple jaw thrust-head tilt maneuver taught in every basic life support course to mechanically assist the lifting of the base of the tongue away from the posterior wall of the pharynx will open the airway to allow air exchange. Also, a shoulder roll to slightly lift the upper torso and facilitate airway opening in a sedated patient will often deter an impending desaturation crisis.
The third intervention is suction, which is almost always intended to also clear the airway of fluids and foreign material. Efficient suctioning to clear the oral cavity and especially the hypopharynx of debris, blood, saliva, and foreign particles is essential in an emergency involving an airway compromise – the most likely emergency to occur in a sedated child. Dental procedures themselves always encroach on the airway and tend to create secretions. Dental instrumentation and materials should be respected as potential foreign bodies. Meticulous attention to suctioning can aid in protection against aspiration of blood, irrigation fluid, or foreign bodies without interfering with completion of dental procedures.
In each situation involving oral sedation, emergency equipment to rescue a patient should always be nearby in the operatory and ready for immediate use. Seconds will count in a serious emergency.
The American Society of Anesthesiologists guidelines for office-based anesthesia [1] specifically address the challenges in dental offices. Procedure rooms in dental offices are usually small therefore compromising access to patients experiencing unexpected complications. Supplemental airway positioning devices that support the patient’s upper torso, neck, and head can be helpful in passively assisting airway management. Dental offices may not have backup emergency power sources; therefore, lighting, communications, and monitoring equipment must have sufficient battery backup or battery-powered resources in the event of power failure. Provisions for backup suction must also be addressed.
Before administering any medications that may compromise respiration, verification of an adequately functioning means to deliver positive pressure ventilation must be made. A bag-valve mask, knowledge and skills in its use, as well as an unlimited source of oxygen are imperative.
An E cylinder of oxygen or a similar portable source of oxygen such as a Jumbo D cylinder should be readily available. The E cylinder or similar portable oxygen reservoir-type rescue device should be available and ready to use within 10–20 s after identifying the complication requiring oxygen.
The E cylinder contains roughly 625 l of O2. A regulator that has a flow meter which controls gas flow through a “nipple” should be fitted to the cylinder. The nipple can be used to supply oxygen to a bag-valve-mask reservoir. A nasal cannula may also be attached to the nipple to provide supplemental oxygen in less critical situations. The threaded attachments on the regulator can be used to connect a high-pressure gas hose to the regulator.
Suctioning can easily be accomplished in a dental setting using a saliva ejector and a high-volume evacuation system. The saliva ejector is beneficial because it is flexible and, most importantly, it is readily available. Unfortunately, its small lumen, fragile connection to the hose assembly, and lack of a venting system limits its usefulness in an emergency that requires large amounts of efficient evacuation. Additionally, the same flexibility that allows for curvature to match the shape of the mouth to the hypopharynx becomes a weakness as this flexibility makes the saliva ejector too weak for definitive suctioning.
The high-volume evacuation is normally equipped with a “straw” or similar hard plastic extension that is both straight and incapable of being curved to go past the base of the tongue and down the pharynx without scraping the posterior wall of the pharynx. It is virtually impossible to reach the area near the vocal cords where blood and saliva collect and block the airway.
A tonsillar or Yankauer suction tip with an associated hose can be attached to the high-speed evacuation (HVE) in less than 30 s. The tip has a lumen that is approximately three times the diameter of the saliva ejector tip and is a flexible hard clear plastic that is precurved to match the curvature from the mouth to the hypopharynx. Efficient high-volume evacuation of blood, saliva, and vomitus can be accomplished with this apparatus. If clogging occurs, the tip can be vented to dramatically reduce the negative pressure at the tip, and debris can be much more easily removed from the intake openings. The tip is smooth and rounded so to not damage the pharyngeal mucosa. It is specifically designed to evacuate this area.
In the emergency scenarios that follow, suctioning an otherwise patent airway should always be considered. If the mouth, pharynx, hypopharynx, and trachea are correctly aligned to facilitate air exchange but the “pipeline” is clogged with saliva, water, blood, and debris, ventilation will be compromised.
Additional devices such as the oropharyngeal and the nasopharyngeal airways are useful adjuncts for keeping the base of the tongue from collapsing against the posterior wall of the pharynx and bypassing large tonsils and redundant tissue. These adjuncts create and maintain airway patency. When employed, these devices allow less restricted, less labored spontaneous breathing or permit much more efficient exchange of air when using assisted ventilation using a bag-valve mask.
Compromised Airway
Introduction
A compromised airway is the most likely complication that will be encountered with oral sedation. The compromised airway may be due to soft tissue blockage such as the tongue falling back against enlarged tonsils, a foreign object (e.g., dropped stainless steel crown), an overdose of the sedative(s) causing loss of tone of the airway musculature, or a particularly sensitive patient who responds in an exaggerated manner to therapeutic doses of a sedative regimen. While a small decrease in the percent saturation will be tolerated in the short run by a patient, there is no way to determine how far the descent will be. Hence, trending of the oxygen desaturation is the key in determining when and how to adjust and open the airway.
Scenario 1
A 3-year-old 19-kg healthy Hispanic male is being treated for dental caries under oral sedation because of patient management problems. He was given 50 mg/kg of chloral hydrate approximately 40 min ago. The child appears asleep and quite limp. The mother was asked to carry the patient to the treatment room. He was laid supine on the dental chair. The patient was positioned on a pediatric dental chair and the oxisensor with an audible pulse-to-pulse tone was placed on the child’s right great toe. The doctor administered 50 % N20. The patient was anesthetized with the correct amount of local anesthesia for restorations in the lower left quadrant. A rubber dam was placed. Readings from the pulse oximeter immediately following the rubber dam application was 98 %. Ten minutes into the restorative procedure, the pulse oximeter demonstrated a steady and rapid decrease in saturation to 90 % then 85 %. The downward trend showed no signs of reversing. Paradoxical chest undulations were noted. The child seemed momentarily difficult to arouse.
Initial Assessment
The child appears to be attempting to breathe normally but no exchange of air can be heard through a precordial stethoscope. Since the restorations were in the mandible, the patient most likely has a non-patent airway due to the practitioner’s depression of the mandible without its support with the nondominant hand.
Acceptable Actions
1.
Discontinue treatment immediately.
2.
Confirm the airway is patent by repositioning the patient’s head with chin lift/mandibular thrust.
3.
Immediately remove the rubber dam, and a thorough evaluation of the airway should be conducted to possibly remove foreign objects or throat packs.
4.
Consider suctioning the mouth and hypopharynx with the saliva ejector.
5.
Remove any patient coverings to allow direct visualization of patient’s abdomen and chest.
6.
Check for normal movement (normal movement should be accompanied by the sound of exchanging of air).
7.
If paradoxical movement is present and no breath sounds are heard, begin the use of positive pressure oxygen with a bag-valve mask connected to 100 % oxygen source. Consider using an oral airway if ventilation is inadequate.
8.
Call 911.
9.
Perform a laryngospasm notch procedure (placement of fingers behind ramus of mandible just anterior to the mastoid process of the skull, pressing medially and anteriorly to open the mandible and simultaneously provide intense pressure).
10.
Continue the combination of the positive pressure oxygenation and laryngospasm notch procedure while suctioning occasionally until breath sounds are heard as patient begins to arouse.
Unacceptable Actions
1.
Continue the dental procedure hoping the child’s oxygenation will improve.
2.
Failure to provide immediate airway management.
3.
Attempting to place an oral airway in an awake patient.
4.
Assume the airway is clear without the need for suctioning.
5.
Failure to ready bag-valve mask and oxygen supply and Yankauer suction device in the operatory should they be needed.
Progression and Summary
The obvious problem in this scenario was airway obstruction, most likely caused by the posterior positioning of the tongue against the soft tissue of the hypopharnyx and tonsils. With proper airway opening via a jaw thrust, the patient normally begins ventilating. One can anticipate that the strong stimulation caused by the jaw thrust at the laryngospasm notch aroused the child from a deeper to lighter level of sedation, and the ventilation caused the SpO2 to rise. Typically, this strong stimulation also causes vocalization and movement of the head, shoulders, and arms in a reflexive manner. The initial assessment of a non-patent airway from mandibular depression was correct.
Respiratory Depression
Introduction
While respiratory depression is a drug-induced partial loss of respiratory drive, it may also be accompanied, in dentistry, by blockage of the airway causing poor ventilation and decreased oxygenation. An open airway, adequate ventilation, and oxygenation (using 100 % oxygen and positive pressure via a bag-valve mask) along with stimulation of the patient can correct the situation.
Case Scenario 2
A hysterical and agitated 2-year-old Caucasian child weighing 14 kg was given 25 mg of midazolam and 45 mg of meperidine as an oral premedication. Thirty minutes later, the drowsy and very limp child was carried to the dental chair for dental treatment. A pulse oximeter was placed on the patient’s toe and the initial reading was 95 %. The doctor placed a nasal hood on the child’s nose and mouth and turned the setting to 6 l/min of 50 % nitrous oxide. The oxygen saturation improved to 97 %. Respirations were noted at 12/min. The doctor began treatment. Several minutes into the planned procedures, the oxygen saturation began to decline. The child was noted to be unresponsive to intense earlobe pinches. The respiration rate decreased further reaching a level of 8 breaths per minute. The reading on the pulse oximeter rapidly plunged to into the lower 80s. There are no apparent spontaneous respiratory efforts as evidenced by the lack of any chest movements or sounds of breathing.
Initial Assessment
The inadequate spontaneous respiration is likely the cause of the problem because of the combined actions of midazolam and meperidine both of which exceeded the therapeutic doses for this child’s weight. Opioids depress ventilation, particularly respiratory rate, and have a more insidious effect when given orally compared to a parenteral route. Resting PaCO2 increases and the normal set point for responding to a CO2 challenge is blunted. The patient may stop breathing. These effects are mediated through the respiratory centers in the brainstem. The apneic threshold – the highest PaCO2 at which the patient remains apneic – is elevated, and the hypoxic drive is decreased [2].
Acceptable Actions and Rationale
1.
Discontinue treatment giving full attention to the patient.
2.
Remove the rubber dam, throat packs, and foreign material from the mouth.
3.
Confirm the airway is patent.
4.
Consider suctioning with the flexible saliva ejector.
5.
Summon the bag-valve mask, emergency oxygen, and Yankauer suction.
6.
Call 911.
7.
Open the airway and immediately begin positive pressure ventilations using a BVM (Ambu bag) attached to the emergency oxygen cylinder. Open the oxygen cylinder and turn the flow meter to 10–15 l/min.
8.
Visualize chest rise.
9.
Visualize fogging of the clear mask as moist, exhaled air as it contacts the inside of the mask.
10.
If there is no evidence of effective ventilation such as chest rise or mask fogging, readjust head position, check mask seal, and strengthen jaw thrust. Consider inserting an appropriate-sized oropharyngeal airway.
11.
Reattempt positive pressure ventilations.
12.
Once ventilation is improved, continue ventilating while waiting for the higher pitched tones of the pulse oximeter indicating increased oxygenation.
13.
Begin to evaluate cause of respiratory arrest.
14.
Consider reversing the sedative agents with the appropriate reversal agents (i.e., flumazenil and naloxone for midazolam and meperidine, respectively – starting with naloxone).
Unacceptable Actions
1.
Failure to recognize ineffective respiratory attempts as indicated by the radical change of respiratory signs
2.
Maintaining a patent airway but without assisted ventilations
3.
Administering reversal agents without demonstrating the capability to efficiently ventilate the patient
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