Chapter 107 Pericardial Surgery

Question 1

What are the layers of the pericardium

Answer 1

Two layers - outer, fibrous layer and the inner serous pericardium

The inner layer has two layers
Parietal and visceral layers
The visceral layer is the epicardium and it invaginates over the heart

The parietal layer is firmly fused to the fibrous pericardium

Question 2

What main fibers are the visceral and parietal layers of the pericardium made up of

Answer 2

Visceral layer - elastic fibers
Parietal layer - collagenous fibers

Question 3

Pathophysiology of cardiac tamponade

Answer 3

Increases in pericardial pressure increases diastolic pressure* within the heart
Atrial wall stretching is limited by tamponade, atrial natriuretic peptide *is not released and is therefore not able to counteract the effects of RAAS.

Question 4

Effects of cardiac tamponade

Answer 4

Reduces stroke volume
CO decreases
Systemic venous and portal pressures increase —> liver congestion, ascites, and peripheral edema secondary from increase in portal and SVP
Poor myocardial perfusion
Pulsus Paradoxus

Question 5

Describe pathophys behind pulsus paradoxus

Answer 5

During inspiration, pericardial and right ventricular pressures decrease
Facilitating venous return to the right atrium and ventricle and pulmonary blood flow.
Intraventricular septum encroaches towards the left decreasing left ventricular end diastolic volume, left heart output, and arterial pressures. *

Question 6

Describe the cause of reduced stroke volume and CO in patients with cardiac tamponade

Answer 6

Increases in pericardial pressure increases diastolic pressure* within the heart - Which reduces stroke volume (decreasing CO)

CO = SV x HR

Question 7

Describe the cause of increased sodium and water retention in patients with cardiac tamponade

Answer 7

Cardiac output decreases, and systemic venous pressure increases, stimulating activation of RAAS (to increase vascular volume and maintain blood pressure) - sodium and water are retained.