Acute myocardial infarction


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Acute myocardial infarction

  1. 1. ACUTE MYOCARDIAL INFARCTION<br />DENTAL THERAPY CONSIDERATIONS<br />Dental therapy considerations for the patient who is status post-MI include reduction in stress related to dental care & possible alteration in drug therapy, dental therapy or both. This patient is classified by the American society of anesthesiologist (ASA) as an ASA II, ASAIII, ASAIV risk depending on the time elapsed since the previous infarction, the number of prior infarcts, and the presence of continued signs & symptoms of cardiovascular disease. <br />NUMBER OF EPISODES ASA PHYSICAL CONSIDERATIONS STATUS <br />Usual ASA II or III considerations to include follow up after therapy by telephone ; supplemental o2 Use of dialogue history to determine level of risk ;usual ASAIII considerations include premedication with nitroglycerine 5 minutes preop (if angina);o2through nasalcannula or nasal hood & follow upUsual ASAIII considerations to include supplemental o2Usual ASA IV considerationsOne documented myocardial infarction at least 6 months previously;no residual cardiovascular complicationsOne documentad episode atleast 6 months previously; angina, CHF, or dysrhythmia presentMore than one documented episode ;most recent one atleast 6 months previously; no further cardiovascular complications.Documented episode less than 6 months previously , or severe post – MI complications<br /> II OR III III OR IV III IV<br />STRESS REDUCTION<br />The degree of stress intolerance, although present in all patients who are status post MI, varies from person to person. Implementation of appropriate steps in the stress reduction protocol should receive serious consideration. Of special importance are intra operative stress reduction & pain control.<br />SUPPLEMENTAL OXYGEN <br />The administration of supplementary oxygen to the patient who is status post- MI minimizes the risk of hypoxia &myocardial ischemia. An o2 flow of 3-5L /min through a nasal cannula or nasal hood is recommended.<br />SEDATION<br />O2 may also be delivered in conjunction with nitrous oxide. N2o-o2 inhalation sedation is the most recommended sedation technique for the cardiac risk patients.<br />PAIN CONTROL<br />Adequate pain control during treatment is a critical factor in increasing safety during dental treatment of the cardiac risk patients. Endogenous catecholamine release is potentially more dangerous to the cardiac risk patient than the 0.01 mg/ml of exogenous epinephrine introduced into the tissues with a properly administered local anesthetic containing epinephrine in a 1.100,000 concentration however vasoconstrictors are contraindicated in patients with intractable cardiac dysrhythmias or any ASAIV cardiovascular risk patients. The use of vasoconstrictor –containing local anesthetics is relatively contraindicated in patients receiving non cardio specific beta blockers, such as propanolol.<br />DURATION OF TREATMENT.<br />The duration of an appointment for the patient who is status post MI is variable but should not exceed the patients level of tolerance. Patients who show the signs of discomfort such as dyspnea , diaphoresis and increased anxiety should be questioned to determined a cause and treatment modified or terminated.<br />SIX MONTHS POST – MI<br />It is strongly recommended that elective dental care ,even procedures as seemingly innocuous as a prophylaxis, be avoided for a patient who is status post MI for atleast 6 months after infarction.<br />Invasive emergency care, such as that for infection and pain, should not be performed in the dental office during this time if possible .the acute dental problem may initially managed pharmacologically through the administration of oral drugs (antibiotics& /analgesics ) alone ;any necessary invasive treatment such as extraction, pulpal exripatio ,should be carried ina more controlled environment such as a hospital dental clinic .<br />Only emergency procedure should be considered for the patients who is status post- MI within 6 months of acute cardiac event . even in this casaes immediate invasive care is warrentied only after medication have been infective in resolving the problem &hospital setting (a controlled environment ) is available for the planned treatment.<br />MEDICAL CONSULTATION<br />medical consultation should be considered before dental management of a patient who is status post MI if , after a full dental, medical & psychological evaluation of the patient the doctor has any dought regarding the status of the patient . if the doctor is contemplating the emergency treatment for their patient within the six month waiting period,medical consultation is strongly suggested before initiating treatment.<br />ANTICOAGULANT/ANTIPLATELET THERAPY <br />Medical consultation is also indicated before any treatment involving the risk of hemorrhage (:periodontal surgery oral surgery , interior alveolar nerve block) if the patient is currently receiving anticoagulant or antiplatet therapy .the post MI use of anticoagulant is much less common today than In the recent past.<br />Dental surgery is frequently performed in patients whose prothrombin time is 20-30% of normal without the development of bleeding problems in most instances thefore proposed dental procedure need not be postponed and the items anticoagulant medication need not be altered however the doctor should take prequations to prevent the occurance of post operative hemorrhage .possible step include a hemostatic dressing placed within a extraction site , multiple sutures in the surgical areas intra oral pressure packs ice packs (extraorel), avoidance of mouth rinses & a soft diet for 48 hours after the procedure additionally inferior alveolar and posterior superior nerve block injections are associated with increased risk of hemorrhage and therefore should be avoided in some cases.<br />MANAGEMENT OF AMI AT THE DENTAL CLINIC<br />Clinical management depends on its recognition and the application of the steps of basic life support. It may be difficult to differentiate immediately between the pain of angina & AMI.<br />Diagnostic clue to the presence of AMI include<br /><ul><li>Symptoms of pressure, tightness, heavy weight.
  2. 2. Substernal , epigastric pain that may radiate to the jaw.
  3. 3. Moderate to severe discomfort.
  4. 4. Longer duration (>30 minutes) than angina pain.
  5. 5. Nausea & vomiting.
  6. 6. Diaphoresis.
  7. 7. Dyspnea
  8. 8. Irregular pulse
  9. 9. Generalized weakness</li></ul>STEP 1: TERMINATION OF THE DENTAL PROCEDURE.<br />With the onset of chest pain, immediately stop the treatment<br />STEP 2: DIAGNOSIS<br />Although at the onset it may prove difficult to distinguish between the pain of angina and AMI, it is apparent that patient is in acute distress and must be treated accordingly. Three clinical potential situations arising are<br /><ul><li>Anginal patient-acute angina attack: the patient with the history of angina is able to tell if the episode of pain is angina. the patient, who is accustomed to treating his/her angina, will usually calmer about the situation than will the doctor, who is probably unaccustomed to patents experiencing acute chest pain during their treatment.
  10. 10. Anginal patient-not angina: an angina patient in whom the chest pain is more intense than usual will become frightened, convinced that “the big one is happening”. Recommended management follows the steps outlined for AMI.
  11. 11. No previous history of chest pain: chest pain developing in a patient with no prior history of acute chest pain normally frightens the patient. It is suggested that the management of chest pain be approached as if it were a angina pectoris, unless it is obviously not of angina origin , as described above.</li></ul>STEP 3: POSITION<br />STEP 4: A-B-C (airway,breathing, circulation).<br />At this point in the AMI, the patient will be experiencing more intense discomfort & may be showing signs of decreased cardiac output (diaphoresis:cool,moist extremities : ashen grey pallor:cyanosis of mucuous membranes and nail bed). A-B-C are assessed and are adequate.<br />STEP 5: D DEFINITIVE CARE.<br />STEP 5 a : ADMINISTRATION OF OXYGEN.<br />Administer oxygen as soon as it is available.evidence sugest that increased arterial o 2 tension decreas he size of infract.o2 delivered through nasal; cannula at 4-6 L/min<br />STEP 5b: SUMMONING OF MEDICAL ASSISTANCE.<br />When an ami is occurring emergency medical services should be activated as soon as possible.<br />STEP 5 c :ADMINISTRATION OF NITROGLYCERINE.<br />If the victim has a history of angina , nitroglycerine which is available with the patient is used immediately. The patients vital sign should be recorded either before the administration of nitroglycerine or shortly thereafter.<br />Nitroglycerine should not be administered in the presence of hypotension.( if systolic bp is below 100.) because it can further decrease the mean arterial pressure. Nitroglycerine acts within 2-4 min. if the pain continues or increases/it alleviates the pain, but the pain returns in a few min then the diagnosis of AMI is considered.<br />STEP 5 d : FIBRINOLYSIS<br />The administration of aspirin has added to the prehospital management of out-of-hospital AMI victims. Aspirin has fibrinolytic preoperties that assists in the process of revascularisatin of the ischemic myocardium . patients should be administered a dose of 325 mg aspirin to chew as soon as it is thought that an AMI is developing.<br />To achive an immediate clinical antithrombotic effect an initial minimum loding dose of 162 mg should be used in AMI. If an enteric coated aspirin is the only preparation available, the first tablet should be chewed or crushjed beforeadministration.<br />STEP 5 e: MONITORING OF VITAL SIGNS.<br />STEP 5 f: RELIEF OF PAIN.<br />Prolong pain in AMI is life threatening. It leades to patient anxiety and contributes to excessive activity of the autonomic nervous system, producing an increase in cardiovascular work load & o2 requirement. In addition, prolonged intense pain is one of the causuatives of cardiogenic shock. Nitroglycerine is inadequate to alleviate the pain . <br />The use of opiod analgesics is recoended for the relief ofpain here. I V administration of 2-5 mg of morphine sulphate reapeated every 5 -15 min provide adequate pain relief and allays apprehension. Additionally morphine increases venous capacitance and systemic vacular resistance,relieving pulmonary congestion & thereby decreasing myocardialoxygen requirement.morphine sulphate may be administered subcutaneously in a dose of 5 – 15 mg.morphine should not be readministered if the respiratory rare is less than 12 breaths per minute.<br />IM injection of thwese analgesics provide adequate pain relief of longer time.IV administration is also considered but readministration is required in a shorter period.<br />Another useful analgesic is a mixture of n2o & o2 which are inhaled.the primary advantage of n2o-o2 is that it provides the patient with a gasseousanalgesic agentthat by itself has little effect on blood pressure.<br />STEP 6: TRANSPORTATION OF THE PATIENT TO THE HOSPITAL.<br />After the patients condition has been stabilized , the patient is transported to primary care facility. The dentist should accompany the patient & remain with the patient until the physician is in attendance. <br />