Cardiac Tamponade

Cardiac tamponade occurs with an increase in intrapericardial pressure due to a pericardial effusion, which is characterized by

               1. Elevation of intrapericardial pressure

               2. Limitation of Right Ventricle Diastolic Filling

               3. Reduction of Stroke Volume and Cardiac Output.

The presence of a pericardial effusion does not necessarily mean tamponade physiology is present.

                Cardiac Tamponade is clinical diagnosis, taking into account the history (potential cause, rate of fluid accumulation), physical exam findings (altered mental status, hypotension, jugular venous distention, pulsus paradoxus) and supporting diagnostic information.

              

                a. ECG: Low voltage, electrical alternans

                b. Cardiac X ray: Water-bottle-shaped heart

                c. Echocardiography: Pericardial effusion; RV diastolic collapse; Righ Atrial notching; 

                   Tricuspid Valve (TV) and Mitral Valve (MV) inflow variation in Dopler velocities of 

                    >40%   and >25%, respectively; dilated Inferior Vena Cava (IVC).

Treatment and Therapy for Cardiac Tamponade

               Initial management consist of volume expansion with intravenous floids to increase preload. Maintain Blood pressure with norepinephrine and dobutamin as needed. Avoid vasodilator and diuretics. The decision to drain the pericardial fluid, as well as the method (surgical or percutaneous) and timing (emergent or elective) oof the prosedure, should be individualized to each patient taking into account the acuity of the patient's condition, availability of trained personnel, and etiology of the effusion.

          Percutaneous pericardiocentesis is a potentially life-threatening procedure and should be performed by trained personnel with hemodynamic monitoring and echocardiographic guidance whenever possible. Complications of pericardiocentesis include cardiac puncture with hemopericardium or myocardial infarction, pneumothorax, VT, cardiac arrest, coronary artery lacertion, bradycardia, trauma to abdominal organs, infection, fistula formation, and pulmonary edema.

          In life-threatening emergent situations, a "blind" percutaneous pericardiocentesis may be needed to stabilize a hemodynamically unstable patient. Ideally, a pericardiocentesis kit can beused, which allows for a rapid procedure with appropiate supplies. The 8-cm, 18-gauge blunt-tipped needle should be attached to a syringe and inserted through the subxiphoid. The tip of the needle is directed posteriorly toward the patient's left shoulder and slowly advanced at a 30-degree angle to the body with gentle aspiration. One suggested way toavoid myocardial puncture is by attaching an ECG electrode to the pericardiocentesis needle. electrical activity will be seen on the monitor when the needle comes intu contact with ventricular myocardium. Aspiration of clear, serous fluid may be from the pericardium or pleural effusion. On the other hand, aspiration of bloody fluid may be from the pericardium or the right ventricle. In general, removal of 50 to10 mL of pericardial fluid should cause a hemodynamic improvement if tamponade is the cause of the hypotension.