ASA Classifications
ASA I: Healthy patient
* ASA II: A patient with mild systemic disease
* ASA III: A patient with severe systemic disease
* ASA IV: A patient with severe systemic disease that is a constant threat to life
* ASA V: Moribund, not expected to live >24 hours regardless of the operation
* ASA VI: A declared brain-dead patient whose organs are being removed for donor purposes
How Calculate BMI
The BMI is calculated by dividing the weight in kilograms by height in meters squared (kg/m2)
<18.5 Underweight 1
18.5–24.9 Normal 1
25.0–29.9 Overweight 1
30.0–34.9 Obese–Class 1 ASA 1
35.0–9.9 Obese–Class 2 ASA 2
≥40.0
Obese–Class 3 ASA 3
which obesity is worse? central or peripheral
Central obesity has a greater risk of metabolic syndrome, cardiovascular disease, airway difficulty, and ventilation management, in addition to an overall greater perioperative risk of complication.
GCS Calculation
RCRI
Cerebrovascular disease, congestive heart failure (CHF), creatinine level >2.0 mg/dL, DM requiring insulin, ischemic cardiac disease, suprainguinal vascular surgery, intrathoracic surgery, or intraabdominal surgery
* Each risk factor contributes 1 point
* Cumulative points calculate risks for Major Cardiac Event
METs * Pt unable to meet 4 METs are at an increased risk of periop cardiac events
How long should you wait to perform elective surgery on a patient who has undergone cardiac surgery?
*Balloon angioplasty: delay 7 days
* Bare metal stent: delay 30 days
* Drug-eluting stent: delay 365 days
How long should you wait to perform elective surgery on a patient who had a myocardial infarction (MI)?
> 60 days—the risk of morbidity and mortality decreases significantly after the first 60 days.
At what percent of arterial oxygen saturation will a patient become cyanotic? At what level of reduced hemoglobin (Hgb) does a patient become cyanotic?
85% arterial oxygen saturation and 5 g/dL
Which side of the stethoscope is used for high-frequency sounds?
High-frequency sounds, such as S1 and S2, murmurs of aortic and mitral regurgitation, and pericardial friction rub, are better heard with the diaphragm. Low-frequency sounds, such as S3 and S4, and the diastolic murmur of mitral stenosis are best heard with the bell.
What causes heart sounds
At the beginning of systole, the ventricles contract, increasing the ventricular pressure and causing the mitral and tricuspid valves to close. Blood rebounds in the ventricles, transmitting vibrations to the chest wall, which can be heard with the stethoscope as S1. Blood then courses silently through the aorta and pulmonary arteries. The second sound occurs when the ventricles relax in diastole, ventricular pressure decreases, and the aortic and pulmonary valves close. The backflow of blood against these valves sets up another series of vibrations, audible as the second heart sounds, S2.
what is PP?
Pulse pressure is the numeric difference between systolic and diastolic blood pressure. The normal pulse pressure ranges from 30 to 40 mm Hg. Causes of increased or widening pulse pressure include hyperkinetic states (anxiety, fever, exercise, hyperthyroidism), aortic regurgitation, and increased aortic rigidity (aging, atherosclerosis). A decrease or narrowing of pulse pressure can be caused by obstructed ventricular output, as in aortic stenosis, or decreased stroke volume from shock or heart failure.
What maneuvers or special positions are used to accentuate heart sound abnormalities?
To accentuate aortic regurgitation, ask the patient to sit up, lean forward, exhale, and hold breath in expiration. For accentuating mitral murmurs or S3, ask the patient to roll onto his or her left side and then listen to the apical area.
What is the difference between stable and unstable angina? How can one differentiate between pain associated with angina and acute MI?
Angina pectoris, or chest pain, is a common obstructive coronary artery disease (CAD) symptom. Reversible myocardial ischemia causes episodes of angina that are often triggered by physical exertion or stress. Symptoms typically last 2 to 10 minutes and resolve with rest or nitroglycerin administration. Patients with stable angina often “know their limits” regarding the amount of exertion until symptoms arise. Physical or emotional stress elicits similar symptoms repeatedly. Patients experiencing unstable angina have changes to the pattern of stable angina. Symptoms become more frequent or severe. Symptoms may also arise with lesser exertion or even at rest. Pain associated with MI is typically more severe and longer-lasting than angina.
What are the heart sounds, and what physiologic event do they correlate with?
S1: closure of the atrioventricular valves
S2: closure of the aortic and pulmonary valves
S3: oscillation of blood in the ventricles during mid-diastole. Usually associated with heart failure
S4: abnormal turbulence of blood associated with stiff ventricular walls
Which heart conditions require antibiotic prophylaxis before dental procedures for the prevention of infective endocarditis?
Prior history of infective endocarditis
* Prosthetic cardiac valves (including transcatheter-implanted prostheses and homografts)
* Prosthetic material for cardiac valve repair (annuloplasty rings and chords)
* Cardiac transplant with valve regurgitation due to a structurally abnormal valve
* Unrepaired cyanotic congenital heart disease (including palliative shunts and conduits)
* Repaired congenital heart defect with residual shunts or valvular regurgitation at or adjacent to the site of a prosthetic patch or device
Which type of dental procedures would require antibiotic prophylaxis in this subset of patients?
All dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region, or consist of an oral mucosa incision.
What is the current recommendation for antibiotic prophylaxis prior to dental procedures for patients with prosthetic joints?
According to the most current American Dental Association (ADA) guidelines, prophylactic antibiotics are generally not recommended in patients with prosthetic joints prior to dental procedures. For patients who had prior complications associated with their prosthetic joint, the ADA recommends consultation with the orthopedic surgeon and for the orthopedic surgeon to select the antibiotic regimen as well.
What are the different classes of anticoagulant and antiplatelet medications?
Oral anticoagulant and antiplatelet medications are generally prescribed for patients with a history of, or at risk for, thromboembolic events, such as deep vein thrombosis, pulmonary embolism, or an arrhythmia that predisposes the patient to clot formation. Oral anticoagulants include the vitamin K antagonist, warfarin, and the newer direct-acting agents, including the direct thrombin inhibitor dabigatran and the factor Xa inhibitors apixaban, rivaroxaban, and edoxaban. Oral antiplatelet agents include clopidogrel, ticlopidine, prasugrel, ticagrelor, and aspirin.
What are the current guidelines for stopping anticoagulant and antiplatelet medications prior to dental surgery?
Stopping these medications can increase the patient’s risk of blood clot development, which could result in MI, thromboembolism, or stroke. The risk needs to be balanced with the consequences of prolonged bleeding, which can potentially be controlled using local measures. The general consensus in most cases is that these medications should not be altered before dental procedures, as the potential risks outweigh the consequence of prolonged bleeding, which can be controlled with local measures. If there is a greater concern for bleeding (e.g., more extensive procedures or patients with comorbid conditions), one may consider temporarily interrupting drug therapy only after consultation with the patient’s physician.
What blood test should be ordered before surgery for a patient taking warfarin, and when should it be drawn?
International normalized ratio (INR) should be drawn <24 hours before the scheduled procedure.
What is the ideal lab value for a patient taking warfarin before dental surgery?
The usual recommended INR level for a patient taking warfarin is 2.0 to 3.0. According to the American Academy of Oral Medicine, moderately invasive oral surgery (i.e., uncomplicated tooth extraction) can safely be performed with an INR of 3.5, with some experts saying even up to 4.0.
