What precautions do I need to take with patients suffering from heart failure or acute pulmonary edema?
Heart failure is described as the inability of the heart to fill and eject the blood or supply the proper amount of oxygenated blood to meet the metabolic needs of the body. Normal heart functioning is influenced by three basic factors: preload, afterload, and contractility of heart muscles.
- Preload is basically an end diastolic volume and a decrease in preload will decrease the amount of stroke volume ejected.
- On the other hand, afterload is defined as resistance to left ventricular ejection.
- The third factor, contractility, is the inherent property of heart muscle and is regulated by the sympathetic nervous system.
In conditions where there is sustained increase in afterload for a prolonged period of time (e.g. hypertension), heart muscles can hypertrophy to meet the increased functional demands leading to left ventricular hypertrophy. The next mechanism to cope with increased functional demand and to maintain normal stroke volume is dilation of the left ventricle.
However, if peripheral resistance continues to rise, hypertrophy and dilation will fail to maintain adequate stroke volume to meet the functional demands resulting in fatigue and dyspnea. If the condition continues to worsen and the oxygen demand remains unmet, more severe complications, such as left ventricular failure (LVF), angina, myocardial infarction and heart failure, may occur.
The etiology of heart failure includes both functional and structural factors. Functional factors include increase workload on heart, which can be due to increase peripheral vascular resistance or high blood pressure. On the contrary, structural factors include damage of heart muscles due to coronary artery disease or myocardial infarction. Other predisposing factors include stenosis of mitral, pulmonary and cardiac valves, and certain conditions (e.g. pregnancy, hyperthyroidism, Pagets disease), increasing the oxygen demand on heart. In pediatric patients, aortic and pulmonary stenosis is the major predisposing factor for heart failure.
Failure of the right ventricle is always preceded by the failure of the left ventricle. In very rare circumstances, there can be an isolated failure of the right ventricle. Left ventricular failure usually manifests clinically as pulmonary edema and respiratory distress; whereas, clinical manifestations of right ventricular failure include systemic venous congestion and peripheral edema.
The typical signs of heart failure include pallor, cold and wet skin, left ventricular hypertrophy, peripheral edema, hepatomegaly and splenomegaly, narrow pulse pressure, ascites and pulpsus alternates. The symptoms encountered by the patients include weakness and fatigue, dyspnea, orthopnea, paroxysmal nocturnal dyspnea and wheezing. In addition, patients suffering from acute pulmonary edema will exhibit moist rales at the base of the lungs, tachypnea, cyanosis and frothy pink sputum.
Prevention and Dental Considerations
Taking an appropriate medical and dialogue history of the patient can best prevent this emergency condition. However, in order to ascertain the patient’s current health status, a physical examination is of the utmost importance. Physical examination should include recording vital signs, examination of skin and mucosal color (cyanosis of nail bed), visibility of the jugular vein (when patient is in the upright position (45 degree), and ankle edema or pitting.
The use of a stress reduction protocol can help minimize the risk of this acute emergency situation. This includes the use of supplemental oxygen, comfortable positioning of the patient and minimizing or eliminating the use of respiratory obstructers, such as rubber dams. No specific modifications of the treatment plan are indicated for patients classified under ASA1 and ASA 2. However, the use of stress reduction protocols may be indicated for ASA 2 patients, if any physical or psychological stress is anticipated during the treatment. The ASA 3 patients are considered to be at increased risk during dental treatment and therefore, use of stress reduction protocol and consultation with the patient’s primary care provider are essential. The ASA 4 patients are considered to be at significant risk. All elective invasive procedures should be withheld and the emergency treatment should only be provided in a controlled environment, such as a hospital setting.
Onset of heart failure is a true emergency condition and it warrants an immediate execution of the steps described below:
- Recognize the problem (extreme respiratory distress) and discontinue the treatment immediately.
- Position the conscious patient in the upright position. This will allow the excess serous fluid to concentrate at the base of alveolar sac and decrease the respiratory distress to some extent. However, if the patient loses consciousness they should be placed in a supine position.
- All dental instruments should be removed from the patient’s mouth and emergency medical services should be activated immediately.
- Stay calm, reassure the patient, and provide basic life support, as needed.
- Definitive care should include administration of oxygen via facemask at the rate of 10ml/min or higher. Vital signs should be monitored throughout.
- Adequate attempts should be undertaken to alleviate respiratory distress and cardiac workload; this includes, bloodless phlebotomy, use of sublingual nitroglycerine tablets (0.8mg-1.2mg), and alleviation of apprehension by administering 2 to 4 mg of morphine (intravenously, subcutaneously, or intramuscularly). Morphine should be re-administered every 15 minutes as needed; however, these drugs are contraindicated in hypoxic patients with cyanosis or mental confusion.
- This is a true emergency situation and the patient almost always requires hospitalization for additional management of the condition. The use of appropriate stress reduction protocol and consultation with the patient’s primary health care provider is essential for future treatment plans.
Malamed, S.F. (2015). Medical Emergencies in the Dental Office (7th ed.). St. Louis, Missouri: Mosby Elsevier.