Cardiothoracic Surgery Flashcards
What are the potential complications of prolonged lateral patient positioning in theatre?
- Tube displacement
- Shunt
- Radial nerve palsy
- Common peroneal nerve palsy
- Saphenous nerve palsy
- Brachial plexus injury
- Ear injury
- Optic neuropathy
- Pressure injury over bony prominence such as iliac crest
What are the anaesthetic implications of oesophageal perforation?
Sepsis highly likely with possibility of shock, so consider ketamine for induction
RSI with rocuronium to avoid increased intragastric pressure of suxamethonium
Left sided double lumen endotracheal tube is preferred over a right sided DLETT as this risks occlusion of right upper lobe bronchus.
Low tidal volume 6-8ml/kg while ventilating both lungs, 5-6ml/kg during one-lung ventilation
Permissive hypercapnoea
What might you see on a CT scan in oesophageal rupture?
- Peri-oesophageal gas
- Pneumomediastinum
- Pneumopericardium
- Pneumothorax
- Pneumoperitoneum
- Surgical emphysema
- Lung abscess or pleural effusion
What clinical signs might suggest oesophageal perforation?
Surgical emphysema
Reduced air entry
Hamman crunch - this is a cracking sound of pneumomediastinum on auscultation
Percussion can be dull or resonant
- Dull if collapse or consolidation
- Resonant if pneumothorax
What are the indications for insertion of an intra-aortic balloon pump?
Acute myocardial infarction
Cardiogenic shock not responding to pharmacological treatment
Cardiothoracic Surgery
Weaning from bypass
Sepsis
Acute MR and VSD
Infants with congenital heart defects
Refractory unstable angina
Refractory LV failure
Cardiomyopathy
What are the absolute contraindications to IABP?
Aortic regurgitation
Aortic dissection
Chronic end stage heart failure not deemed operable
Aortic stenting
What impact does an IABP have on the following?
- Aorta
- Left ventricle
- Heart
- Blood flow
- Reduced systolic pressure, increased diastolic pressure
- Reduced systolic pressure, reduced end diastolic pressure, reduced volume and reduced wall tension
- Reduced afterload, reduced preload, increased cardiac output
- Increased coronary blood flow
Why is helium used to inflate an IABP?
It has a very low density so it can inflate and deflate the balloon very quickly
It is rapidly absorbed into the blood in the event of balloon rupture
What is the equation for coronary perfusion pressure?
CPP = ADP - LVEDP
CPP = Coronary perfusion pressure
ADP = Aortic diastolic pressure
LVEDP = Left ventricular end diastolic pressure
What are the complications of IABP?
Balloon rupture and gas embolus
Haemolysis and thrombocytopenia
Occlusion of cerebral or renal arterial supply
Limb ischaemia
Aortic trauma or dissection
Bleeding and infection
Tamponade
What are the components of the DeBakey classification of aortic dissection?
Type 1 = Ascending and descending Aorta
Type 2 = Limited to ascending aorta
Type 3 = Limited to descending aorta
Note that in type 3 the dissection must be distal to the left subclavian artery
What are the components of the Stanford classification of aortic dissection?
Stanford Type A = DeBakey 1 and 2
This means ascending aorta or both ascending and descending
Stanford type B = DeBakey 3
This means just descending aorta
Which radial artery should be used in aortic dissection?
Type A = left radial, as the right arm may be affected by the dissection
Type B = right radial is preferred as it is further from the site of dissection
What are the knock-on physiological effects of severe mitral stenosis?
Raised left atrial pressure
Chronic pulmonary venous congestion
Pulmonary hypertension
Reduced lung compliance
Right ventricular dilatation
Tricuspid regurgitation
Raised central venous pressure
Hepatic congestion
Ascites
Peripheral oedema
How does mitral stenosis cause peripheral oedema and ascites?
Mitral stenosis causes increased left atrial pressure and an increased resting diastolic mitral valve gradient.
This causes pulmonary hypertension and right ventricular hypertrophy.
This causes tricuspid regurgitation, which causes increased central venous pressure.
This causes hepatic congestion, which then leads to ascites and peripheral oedema.
