Pericardial Tamponade

Question 1

great vessels of the heart

Answer 1

the aorta, pulmonary artery, pulmonary vein and the superior and inferior vena cava

Question 2

what is the pericardium

Answer 2

The pericardium is a fibro-serous, fluid filled sack that surrounds the muscular body of the heart and the roots of the great vessels

Question 3

layers of the pericardium

Answer 3

a tough external layer known as the fibrous pericardium, and a thin, internal layer known as the serous pericardium

Question 4

layers of the serous pericardium

Answer 4

the outer parietal layer which lines the internal surface of the fibrous pericardium and the internal visceral layer which forms the outer layer of the heart (also known as the epicardium).

Question 5

cells of the serous pericardium

Answer 5

single sheet of epithelial cells, known as mesothelium.

Question 6

pericardial cavity

Answer 6

Found between the outer and inner serous layers, is the pericardial cavity, which contains a small amount of lubricating serous fluid.

Question 7

fluid in the pericardial space

Answer 7

Normally there is 15-30 ml of fluid in the pericardial space between the parietal and visceral pericardium. This fluid serves to minimize the friction generated by the heart as it contracts and moves about within the thoracic cavity.

Question 8

pathophysiology of tamponade

Answer 8

The fibrous pericardium is relatively inextensible and can pose a problem when there is an accumulation of fluid, known as pericardial effusion, within the pericardial cavity.

This rigidity means that the heart is subject to the resulting increased pressure. The chambers can become compressed, thus compromising cardiac output.

Tamponade is the physiologic state when the pressure from intra-pericardial fluid accumulation increases, compressing the heart and causing decreased cardiac output.

Once you’ve reached the limit of the pericardial compliance, pressure finally does start to increase, first equalizing with RV diastolic pressure then the left. Cardiac output (CO) drops, so contractility and rate increase to compensate.

Question 9

stages of tamponade

Answer 9

1. Fluid filling the recesses of the parietal pericardium
2. Fluid accumulating faster than the rate of the parietal pericardium’s ability to stretch
3. Accumulation that exceeds the body’s ability to increase blood volume to support RV filling pressure

With slow accumulation of fluid, the compliant parietal pericardium stretches without much change in pressure. Gradual accumulation of fluid is well tolerated as some dialysis patients chronically have up to one litre of pericardial effusion. Lower-right-sided pressures result in evidence of compressive effects on the right heart first.

Rapid accumulation is bad. The pericardium doesn’t stretch and the CO drops dramatically. Rapid pericardial fluid accumulation leads to elevated intra-pericardial pressure and myocardial compression. The rate of accumulation rather than volume is responsible for hemodynamic instability.

Question 10

causes of tamponade

Answer 10

Whatever can cause an effusion can cause tamponade

Classified as Traumatic vs Non-traumatic

Question 11

non- traumatic causes

Answer 11

Malignancy
Uremia/ESRF
Radiation
Drug reaction
Autoimmune disorders
TB
Iatrogenic
Aortic dissection
Idiopathic

Question 12

symptoms of pericardial tamponade

Answer 12

*dyspnea (most common, 87-88% sensitivity)
*chest pain, fullness, palpitations
*nausea, abdo pain (hepatic/ visceral congestion), anorexia
*dysphagia
*lethargy, weakness, fatigue (decreased CO)
*fever
*cough

Question 13

clinical findings

Answer 13

*distended neck veins
*muffled heart sounds
*hypotension
*tachycardia (77% sensitivity)
*pulsus paradoxus
*absent apex beat
*tachypnoea

Question 14

Chest pain, cough, fever, lethargy, palpitations occurrence

Answer 14

<25%

Question 15

beck triad

Answer 15

Hypotension
Jugular venous distension
Diminished heart sounds
Only 33% of patients have all three

Question 16

jugular venous distention

Answer 16

it is paradoxical and happens during inspiration

Question 17

pulsus paradoxus

Answer 17

Sensitivity 82%
Negative intrathoracic pressure with inspiration increases venous return to the right heart and causes increased filling of RV.
This overfilled RV bulges into the LV, decreasing its available volume.
Decreased left sided stroke volume means decreased cardiac output and decreased blood pressure with inhalation.
This ventricular interdependence happens normally.
The opposite occurs with exhalation. Increased pressures in the chest decreases right heart filling allowing more space for the left ventricle to fill and thus increased cardiac output. So, exhalation means higher blood pressures.
Exaggerated decrease in systolic blood pressure (>10 mm Hg) with inspiration
Also occurs with asthma, constrictive pericarditis, pulmonary embolism, and COPD

Question 18

differential diagnosis

Answer 18

Massive PE
Tension Pneumothorax
SVC obstruction
Chronic constrictive pericarditis
Air embolism
RV Infarct
Severe CCF/cardiogenic shock
Extrapericardial compression: haematoma, tumour

Question 19

special investigations: CXR

Answer 19

Cardiac silhouette may appear normal
At least 200-250 ml pericardial fluid is needed for cardiomegaly to be visible on CXR? - typical bottle shape

Question 20

special investigations: ECG

Answer 20

Sinus tachycardia
Decreased QRS voltage
Electrical alternans

Question 21

special investigations: Echo/ bedside ultrasonography

Answer 21

NB: clinically significant tamponade is a clinical diagnosis and echocardiographic signs of tamponade are not in itself an indication for acute intervention
Pericardial effusion (Fluid around the heart will show up as a black stripe)
Collapse of the right atrium in late diastole Collapse of the right ventricle free wall in early diastole
Left atrial collapse is highly sensitive for tamponade
A small, slit-like, hyperdynamic LV
Swinging to and fro of the heart within the pericardial fluid
IVC plethora (Dilation of the IVC and hepatic veins)

Question 22

special investigations: CT and MRI

Answer 22

Not suitable in the critically ill patient!!!!!!
Sensitive and specific for detecting pericardial effusion/ an alternative to echo

Question 23

treatment

Answer 23

*Drainage of pericardial fluid
*Initial medical management steps
-Optimize oxygenation
-Fluids to increase right sided filling pressures (Indicated in patients with signs of hypovolemia; May increase cardiac size and pericardial pressure and be harmful in euvolemic or hypervolemic patients
-Avoid PPV (positive pressure ventilation) – positive intrathoracic pressure will further decrease venous return and blood pressure – leads to impaired cardiac filling and worsen tamponade

Question 24

drainage procedures

Answer 24

pericardiocentesis
pericardial window
thoracotomy

Question 25

indications of pericardiocentesis

Answer 25

-Haemodynamic compromise (pre-arrest) if patient too unstable to await pericardial window in operating room
-Tamponade
-Cancer patients to determine malignant vs. post-radiation vs. infectious pericarditis
-Failure to respond to treatment
-Suspected bacterial infection

Question 26

pericardiocentesis procedure: blind

Answer 26

-The standard approach is subxiphoid, with you standing on the patient’s right.
-Identify landmarks
-After prepping and injecting some local anesthesia, identify the left xiphocostal angle, and slide down about 1 cm, no further than approximately 2 fingerbreadths.
-This will be your entry point, 30 to 45˚ to the abdominal wall, aimed at the midpoint of the left clavicle. Aspirate as you advance the needle.
-The heart is quite anterior, so any angle greater than 45 degrees is too much and makes you more likely to puncture the stomach or liver.
-If your first advance fails to produce any fluid, withdraw the needle to just below the skin and redirect it a little more medially.
-Watch cardiac monitor for a change in the QRS morphology, or ST elevation if the needle touches the myocardium
-Aspirate fluid/blood
-Consider placing a catheter/pigtail
-Blood stained pericardial fluid will not clot whereas intraventricular blood will

Question 27

pericardiocentesis procedure: ultrasound guided

Answer 27

-The most common ultrasound-guided approach is apical
-Here, you’ll want to position yourself to the patient’s left.
-Find the apex via palpation (or simply with the ultrasound)
-Insert the needle approximately 1 cm lateral to this, with the point directed toward the patient’s right shoulder,
-Use the same insertion-aspiration technique as above, visualizing the advance of your needle point with the ultrasound.
-Make sure to advance over the cephalad portion of the rib inferior to your insertion point, avoiding the neurovascular bundle below the rib above.
-Direct visualization is necessary for this approach, since the lingula lies very close to the apex, meaning that you have a high risk of causing a pneumothorax.

Question 28

pericardial window

Answer 28

is the definitive surgical procedure for pericardial effusions

Question 29

thoracotomy

Answer 29

Posttraumatic tamponade
Dissecting thoracic aorta aneurysm
Rupture of the myocardium
Pericardiocentesis is often unsuccessful in patients with haemorrhagic tamponade

Question 30

What are the complications of pericardiocentesis?

Answer 30

Dysrhythmia
Pneumothorax
Perforated myocardium
Coronary artery laceration
Mammary artery laceration
Liver laceration

Question 31

disposition

Answer 31

Pericardial effusion may, in time, lead to cardiac tamponade.

Cardiac tamponade causes shock and ultimately death if left untreated

Patients with non-traumatic cardiac tamponade (clinically compensated) should be admitted to a high-dependency area for close observation while a definitive drainage procedure is planned and organized.

Decompensated tamponade requires urgent drainage and the choice of management will depend on the aetiology (surgery vs medicine/cardiology)