|MEDICAL EMERGENCIES IN THE DENTAL OFFICE
Fortunately, medical emergencies in the dental office are a rare occurrence. Unfortunately, this rarity prevents us from becoming comfortable with management of problems, and worse still, may lead to complacency. In light of their uncommon occurrence, it is useful to revisit the subject, sometimes from a different perspective. The perspective taken for today's discussion is a relatively broad one, allowing for a "from first principles " approach to the prevention of preparation for, recognition of and action involved in the management of medical emergencies.
A medical emergency is a stress induced, relatively sudden, acute, uncontrolled failure of physiologic adaptation capability (or decompensation in the face of stress ).
A. Stress induced: This implies that there is usually a more or less recognizable cause or identifiable stress that is driving the system toward failure. This could be the presence of an allergen, anxiety, drugs or foreign object in the airway that stresses the system maximally and beyond in such a manner that the system is no longer able to cope.
B. Relatively sudden: While some emergencies occur rapidly, many take time to evolve. An identifiable, gradual chain of events often conspire to lead a patient to the point where they are maximally stressed and failure occurs as the last link in the chain. Prevention centres on breaking the chain of events prior to reaching failure.
C. Acute: The central theme of all emergencies is that they are acute occurrences happening right now. From this perspective they require immediate recognition and attention.
D. Uncontrolled failure: Emergencies rarely display intrinsic control by the patient. Clearly, the patient’s system has lost the ability to respond to the stress and extrinsic help must be brought in. The key to management of emergencies is the resumption of control by the clinician.
E. Decompensation: Loss of compensation implies that compensation was happening in the first place. In the normal healthy subject, this ability to compensate for stress or strategic reserve is maximal and much has to happen before the system is no longer able to adapt to rising levels of stress. In the medically compromised patient, some of this reserve has been lost as a function of the underlying illness and decompensation or failure occurs earlier and in the face of lower levels of stress.
An excellent model for medical emergency is the coronary stress test. In this example, the stress is the treadmill, specifically related to its slope and its rate. As the slope and rate of the treadmill increases, the stress to the heart and the demand for coronary perfusion of the myocardium increases.
While the angina attack or the MI that the patient experiences while having the test is a relatively sudden event, the steps leading to the acute event took place over a well defined interval and occurred in a clearly laid out pattern.
Although the progression to the angina attack or the MI may have been drawn out, the event itself is acute and must be recognized and dealt with immediately by the stress lab technician. If the patient has gone on to having an MI during the stress test, the extent of the damage is essentially uncontrolled unless the technician intervenes, stops the test and begins supportive management immediately.
The stress test is designed to assess the patient's coronary reserve. "Failing" a stress test means the patient's reserve was minimal in the first place and that decompensation or failure is likely to occur very early in the process of applying stress to the system.
3. THE CORNERSTONES OF EMERGENCY MANAGEMENT
Viewed from this perspective, the management of emergencies can be thought of as occurring in four domains. Each domain is interdependent with the other domains and requires support form the other three.
Prevention: The most successful way to manage an emergency is to prevent it form happening in the first place. This is based on:
a) An assessment of relative risk: This is the ‘product’ of medical compromise multiplied by the complexity of the procedure. The more ill the patient and the more invasive the procedure, the greater the likelihood of an emergency. Careful medical assessment is the key to determining where the patient is sitting on the compensation curve, and therefore, their medical risk.
b) Risk reduction and hazard avoidance: Having recognized increased risk (as a function of illness and procedural complexity), prevention revolves around risk reduction (medical tune up in order to ensure optimal control of medical compromise) and hazard avoidance (reduce anxiety, avoid allergens, avoid drug interactions, reduced pain, shorter procedures, avoid aspiration, refer, etc.).
a) Medical assessment: Careful medical assessment not only allows for identification of risk and thus avoidance, it should also give the practitioner an indication of the type of medical emergency that the patient may have, for example: bronchospasm in the asthmatic. Having this information readily at hand when dealing with an emerging problem will save on considerable guesswork and allow the practitioner to zero in on the most likely diagnosis.
b) Emergency kit: An important aspect of preparation for emergencies is the purchase and careful maintenance of an emergency kit. This should include key drugs and equipment needed to manage emergencies. A key example of this is to ensure that there are syringes and needles for the delivery of emergency drugs when needed. A further point to stress is the need to monitor expiration dates and the condition of equipment such as airways or masks. The following is a short list of recommend drugs and equipment:
1. oxygen.............................................................. 6 1/min by mask
2. epinephrine (alpha and beta agonist)................ 0.5 to 1 ml of 1:1,000 IM
nitroglycerine (vasodilator)................................ 0.3 mg sublingual to 3 doses (if no response…assume MI and call 911)
4. salbutamol (Ventolin) (bronchodilator).............. 2 puffs by inhalation
5. diphenhydramine (Benedryl) (antihistamine).... 50 mg IM or PO
6. sucrose............................................................. soda PO
glucagon........................................................... 1 mg IM
8. ASA ………………………………………………. 325 mg PO
9. Lorazepam……………………………………….. 1 mg SL
10. oxygen bottle with regulator and gas tubing
11. an assortment of adult and paediatric airways and face masks
12. ball valve bag for ventilation (Ambubag)
13. various syringes and needles for delivery of emergency drugs
16. tonsil suction tip
17. file cards with emergency protocols and drug dosage information
c) Clear guidelines: During the middle of a medical emergency is no time to be figuring out what to do next. This has been recognized by the American Heart Association in their guidelines for CPR and ACLS (Advanced Cardiac Life Support). These guidelines, once learned, allow the rescuer to follow standard protocols for the management of cardiac emergencies. They are based on sound judgement and scientific study and most importantly, are detailed IN ADVANCE. Similar thinking for the management of other emergencies is equally reasonable. Taking the time, in advance, to think through an emergency situation, outlining it on a file card, familiarizing all staff, in advance, and then placing the card in the emergency kit will tremendously simplify problem management.
d) Practice: The AHA again recognizes the importance of rehearsal for the management of emergencies. Annual mock emergencies not only keeps the staff sharp but it is also an excellent opportunity to recheck the emergency kit and restock stale dated medications.
e) Vigilance: Watching and listening for potentially emergent situations whether they be in the operatory, the other operatory or the waiting room will help to prevent problems before they occur and to act on emerging problems early in their progression. This requires constant vigilance and observation for the patterns of " problems waiting to happen".
Recognition: Early recognition and intervention is essential to the successful management of emergencies once they have happened. The comment, " the right thing was done too late " may be the epitaph for the unsuccessful emergency intervention.
a) Monitoring: Monitoring of patients takes many forms. The most extreme is intensive ICU or OR monitoring that involves EKG, pulse oximetry, blood pressure and so on. In the normal dental office, these items are usually unnecessary and unfamiliar. What is done is moment to moment monitoring through assessment of colour, respiratory rate and distress pattern, level of consciousness and observation of overt signs of distress. Dentists are particularly good at this sort of monitoring because we are constantly watching for signs of discomfort or inadequate anaesthesia that may complicate our procedure. The most useful practical technique is the comparison of patient's state of mind as we progress through treatment. How often have you asked a patient " are you OK", after observing some subtle mood or postural change in the patient? This type of monitoring is crucial for the detection of problems early in their progression.
b) Context: The importance of an accurate and up-to-date medical history cannot be overstressed. If a patient is decompensating, it is usually a function of a lack of strategic reserve in a given system and it is usually obvious from the medical history. A patient with a history of six heart attacks in the past is likely having another one if he collapses in your waiting room. This allows for early diagnosis and appropriate management.
c) Assessment of severity: Determining the severity of a problem is a function of the interplay of a complex series of observations and then the performance of mental arithmetic in order to extrapolate ahead and try to predict just how bad things might get and how soon they might get there. If a patient was fine two minutes ago and is now swelling visibly and wheezing audibly following the administration of a local anaesthetic, its a good bet that he going to continue getting worse in a hurry. This determination of how severe things are (and how severe they are going to get) directs management in terms of the intensity of response. The above noted patient needs epinephrine right now and an ambulance ride as soon as possible if he hopes to survive the day. On the other hand a simple episode of syncope from which the patient recovers quickly may only require repositioning and reassurance before resuming the treatment. Measurable parameters like heart rate, blood pressure and respiratory rate are much more objective guides to the ongoing status of the patient and as such will be very helpful in determining whether a patient is worsening or improving.
d) Diagnosis and differential diagnosis: In some cases, the diagnosis will be obvious. Examples of this are epileptic convulsions or airway obstruction following loss of a crown down the patients's throat. In these cases, the obvious diagnosis leads to early appropriate management. In other situations, the diagnosis of the emergency situation may be obscure. An unconscious patient lying on the floor of your waiting room may have fainted, overdosed on drugs, hypoglycaemic, dead, having a heart attack or simply be asleep. Having a working differential diagnosis will direct the early steps in managing this situation to supporting the basic ABC's and to determining the exact nature of the problem. Quick review of the medical history is often helpful at this point. In other circumstances, the results of early intervention may be diagnostic if applied appropriately. An excellent example of this is the patient with chest pain. If the nitroglyercine does not clear up the problem after three dosages, then a call to the ambulance and a trip to the local emergency room is indicated to rule out an MI.
Action: Action may be indicated even before an emergency situation is clearly diagnosed. Supportive measures such as airway maintenance will buy valuable time for the clear determination of the problem and definitive intervention.
1. Stop the procedure and manage the emergency.
2. ABC's of emergency management: airway, breathing and circulation
3. 911....... Get help as soon as the situation appears serious
4. On the basis of diagnosis:
a) Maneuvers, eg. Trendellenberg position, Heimlich maneuver
b) Drugs......see emergency kit and protocol card
c) Follow up........911 (ambulance), emergency room or physician
For each of the following sample emergencies, consider the affected system, the pathophysiology of the emergency and add detail with respect to the mechanisms of action, dosages and routes of the emergency drugs.
E. Sample Emergencies:
Prevention Preparation Recognition Action
syncope anxiousness vigilance pale, sweaty position
history protocol confused O2
position kit LOC
allergy history of vigilance wheeze adrenaline
drug allergy protocol swelling benedryl
avoid allergen kit rash O2
airway children vigilance panic Heimlich
obstruction rubber dam protocol crowing suction
"strings" kit cyanosis remove FB
broncho- history of viligance wheezing puffer
spasm asthma protocol distress adrenaline
prophy puffer kit cyanosis O2
angina history of viligance chest pain rest
angina protocol SOB NTG
low stress kit
MI history of viligance chest pain NTG
angina or MI protocol (CPR) SOB analgesic
low stress kit loss of ASA
prophy NTG consciousness 911
pulselessness CPR (ABCs)
hypo- history of DM vigilance light headed sucrose PO
glycemia drug history protocol sweaty
early AM kit loss of glucagon
normal meal consciousness 911
seizure history of vigilance prodrome protect
eplilepsy protocol convulsions airway
medications kit loss of 911
avoid stimulus consciousness benzodiazapine