Cardiac Tamponade Flashcards
(12 cards)
What clinical features might suggest a patient who has undergone Coronary Artery Bypass Surgery has developed a cardiac tamponade
Hypotension / Cardiogenic Shock
Cardiac Arrest
Raised Jugular Venous Pressure / Increasing Central Venous Pressure
Oliguria
Increasing Vasopressor Requirements
Sudden reduction or cessation of drain output (postoperatively)
Tachycardia
Dyspnoea
Muffled Heart sounds
Pericardial Rub (may not be present post surgery)
Sharp Chest Pain (again unreliable in the context of recent surgery)
Pulsus Paradoxus:
An abnormally large reduction in systolic blood pressure during inspiration.
During Spontaneous ventilation the full right heart encroaches on the left and due to blood pools in the pulmonary vasculature. Both of these things reduce left heart filling and hence cause the decrease in systolic pressure. In tamponade this effect is exacerbated and the difference in pressure between the left and right sides of the heart is lost. Positive pressure ventilation has a similar effect except it occurs during expiration.
Kussmaul’s Sign: A rise or lack of a fall in the JVP with inspiration which occurs due to the failure of the constricted right heart to accommodate the increase in venous return that occurs with the drop in intrathoracic pressure that occurs during spontaneous respiration.
What are the causes of cardiac tamponade
Chest Trauma (usually penetrating trauma)
Type A aortic dissection
Iatrogenic following interventional cardiology procedures or post cardiac surgery
Infectious Pericarditis
Non infectious Pericarditis e.g. idiopathic autoimmune uraemic or malignant
What are the echocardiographic findings in cardiac tamponade
Collapse of cardiac chambers
IVC dilatation (due to right heart compression)
Leftward shift of the intraventricular septum during spontaneous ventilation
Increased variation in intracardiac blood flow with respiration
Pulmonary Effusion (greater than 20mm is considered significant)
“Swinging Heart” (https://youtu.be/HmaJplj55r4)
What are the Chest X ray findings in cardiac tamponade
Enlarged or globular appearance of the cardiac silhouette
Evidence of Heart Failure e.g. pulmonary oedema
What are the ECG findings in cardiac tamponade
Sinus Tachycardia
Atrial Arrhythmias
Low Voltage QRS complexes (due to the attenuation [reduction] of electrical impulses)
Electrical Alternans (a beat to beat variation in the QRS amplitude and axis
What are the Pulmonary Artery Catheter findings in cardiac tamponade
Equalisation of diastolic pressures in all heart chambers
Pulmonary Capillary Wedge Pressure may be raised in patients with left heart compression
What are the surface landmarks for needle insertion for pericardiocentesis
1-2cm inferior to the left xiphochondral junction (subxiphoid)
1-2cm lateral to the apex beat within the 5th, 6th or 7th intercostal space (apical)
Fifth left intercostal space close to the sternal margin (parasternal)
What are the complications of Pericardiocentesis
Laceration of ventricle, coronary vessel, intercostal vessel or thoracic vessel all with consequent haemorrhage
Puncture of abdominal viscera or peritoneal cavity
Pneumopericardium
Arrhythmias
Pericardial decompression syndrome, i.e. left ventricular dysfunction resulting in pulmonary oedema or cardiogenic shock.
What are the haemodynamic goals when anaesthetising a patient with cardiac tamponade
Maintain preload by replacing lost volume
Maintain sinus rhythm (as an arrhythmia will have a very deleterious effect on left ventricular filling and further reduction in cardiac output)
Avoid Bradycardia (stroke volume will be impaired) so normal to high heart rate is required to maintain cardiac output
Maintain systemic vascular resistance (which will be high due to the sympathetic response but will likely be compromised by most anaesthetic agents) to maintain coronary perfusion
Maintain cardiac contractility by avoiding myocardial depressants
What is the emergency management of cardiac tamponade
Patients may require an urgent decompressive sternotomy on cardiac ICU as there may not be time to return them to theatre if they are significantly compromised. Management therefore comprises:
Call for senior help, both anaesthetic and cardiothoracic
Contact theatre team and perfusionist (in case the patient will need to go back onto bypass)
Initiating major haemorrhage protocol
Assessment and managements of patients A-E
If arrested an anaesthetic may not be immediately required
What are the immediate effects on the left ventricle following the initiation of positive pressure ventilation during tamponade
There is an acute rise in intrathoracic pressure which causes compression of the pulmonary vasculature and a acute rise in venous return to the left ventricle, there is also a shift of the intraventricular septum to the right, increasing stroke volume
This rise in intrathoracic pressure also causes a further reduction in the venous return to the right heart which consequently results in reduced blood being delivered to the left ventricle with a subsequent drop in preload to the left ventricle and ultimately a further reduction in cardiac output
What is the ventilatory strategy, when anaesthetising for cardiac tamponade
Because the right ventricle is compressed early in acute tamponade with a consequent reduction in filling and is therefore at risk of right ventricular failure when initiating positive pressure ventilation.
The aims of a ventilatory strategy are:
Use the lowest possible ventilatory pressures whilst maintaining normoxia and normocapnia
