CARDIAC TAMPONADE IN CARDIOTHORACIC SURGERY.pptx

cardiac tamponade

1. CARDIAC TAMPONADE: AETIOLOGY AND MANAGEMENT

2. INTRODUCTION It is a French word of German origin meaning compression of the heart. Pericardium is not essential e:g postop cases. Cardiac tamponade is a medical emergency. One of the 6 life threatening conditions in trauma . Presents as obstructive shock .

3. Anatomical considerations a fibroserous , fluid filled sack that surrounds the heart and the roots of the great vessels between the outer and inner serous layers, is the pericardial cavity , which contains a small amount of lubricating serous fluid. This fluid serves to minimize the friction generated by the heart as it contracts and moves about within the thoracic cavity.

4. Anatomy

5. Anatomy

6. Aetiology Bleeding -spontaneous -trauma - postop : clots, removal of pacing wires Effusions

7. Aetiology - Acute tamponade Usually due to traumatic rupture of ventricle as a result of a procedure - endocardial perforation from cardiac cath , CVP catheters, pacemaker insertion. Penetrating wounds or blunt trauma – RTA, CPR. Aortic dissection Myocardial infarction with ventricular rupture Cardiac surg – direct bleeding, Dressler’s syndrome

8. Pathophysiology The initial portion of the pericardial pressure volume curve is relatively flat ie relatively large increases in volume produce little changes in pressure up to a certain limit. Compensatory mechanisms maintain the cardiac output (SV ×HR), BP (vasoconstriction), higher filling pressures – CVP, LVEDP. Onset of tamponade depends on -rate of fluid accumulation -pericardial compliance -Intravascular volume

9. Pathophysiology … Pericardial effusion of significant volume or rapidly accumulated fluid leads to increased pressure in pericardial space throughout the cardiac cycle During inspiration, as RV volume increases the RV is unable to expand into the maximally stretched pericardium. Therefore, the interventricular septum bulges to the left, decreasing LVEDV and there by decreasing cardiac output, causing a decrease in SBP during inspiration Diastolic equalization of pressures haemodynamic collapse.

10. Clinical features tachycardia and dyspnoea hypotension with narrow pulse pressure ( BP may remain normal/elevated until cardiovascular collapse is imminent) ↑ JVP: the y descent is abolished due to an increase in intrapericardial pressure, preventing diastolic filling of the ventricles ƒDecreased (muffled)heart sounds ƒ Pulsus paradoxus (decrease in SBP of >10 mm with inspiration) Oliguria or anuria – peripheral vasoconst

11. Clinical features.. Get a manual BP cuff and inflate until above SBP then slowly release until you start to hear Korotkoff sounds. At first, you should just hear them during expiration; slowly release until you hear a sound in expiration and inspiration. The difference between when you first hear the sounds and when you hear them in both phases of respiration is the pulsus paradoxus .

12. Clinical features.. May also be seen on A-line tracing a pulsus paradoxus greater than 10 mm Hg is suggestive of cardiac tamponade . Pulsus paradoxus also occurs in CCF, asthma and pulmonary embolism.

13. Clinical features… Increased CVP Hepatomegaly Peripheral oedema , ascites and pleural effusion in chronic tamponade

14. Investigations General – FBC, SEUC, viral screening Specific -CXR -ECG -2D ECHO.

15. Investigations.. ECG - sinus tachycardia, low-voltage QRS complexes, alternation of QRS complexes (usually in a 2:1 ratio), PR segment depression. CXR: globular heart, calcifications, evidence of chest wall trauma or thoracic malignancy. May be normal in the ER. Echocardiography: transthoracic echocardiogram is the investigation of choice. Difficult window postop . A negative result does not exclude tamponade . Postop tamponade is a clinical diagnosis.

16. CXR

17. ECG Low QRS voltage Tachycardia Electrical alternans : beat- to - beat variation in P, R and T wave amplitude. Seen in 10-20% of cases of tamponade and 50% of these cases are neoplastic in origin

18. Electrical alternans

19. 2D ECHO

20. Investigations… Pericardiocentesis ; aspirate sent for culture and cytology. Pericardial biopsy

21. Treatment - aims Relieve the tamponade Treat underlying cause

22. General Oxygen therapy Volume expansion to maintain adequate intravascular volume - small boluses work best. Positive inotropic drugs: eg dobutamine . Positive-pressure mechanical ventilation should be avoided because it may decrease venous return. Avoid diuretics

23. Treatment Depending on the stability of the patient and the underlying cause: a) paraxiphoid pericardiocentesis ; b) subxiphoid drainage of the pericardial collection; c) anterolateral thoracotomy drainage of the pericardial collection with a pericardial window ± preliminary subxiphoid approach. d) re-opening of median sternotomy – crash tray.

24. Pericardiocentesis ECG or ECHO – guided Dangerous procedure May be negative if blood is clotted False positive result if there is entry into a ventricle usually RV (anterior). Laceration of a coronary vessel

25. Pericardiocentesis