Cardiothoracics Flashcards
Two lung positive pressure ventilation in lateral position - where are ventilation and perfusion the most
Ventilation more in non dependent lung
Perfusion greater in dependent lung
Positive pressure ventilation of ONLY dependent lung in lateral position
Which part of lung will have more
- perfusion
- ventilation
Dependent lung positive pressure ventilation
Perfusion at base
Ventilation at the top
Two lung ventilation lateral positive positive pressure ventilation where will the dead space be greatest
Non dependent lung
Act normal and for CPB
Normal 70-140
Act 4x normal or 480 for cpb
Act can be prolonged by
Haemodilution Overfilling Inadequate mixing Thrombocytopenia Dilution or procoagulation deficiency Warfarin Aprotonin
Absolute indications for OLV
Prevention of infection or contamination ie BPF Isolation pulmonary haemorrhage Control of distribution of ventilation Unilateral lung lavage Giant unilateral Bullae Pneumonectomy
How does IABP work
Polyurethane Catheter into femoral artery and into descending aorta. Positioned distal to left subclavian but proximal to renal arteries
Helium inflates in time with mechanical cardiac cycle
Balloon deflated in systole when AV valve opens
Ballon inflates in diastole when AV valve closes
Inflation linked to mechanical cardiac cycle either times via ECG or IABP waveform or can be timed.
Support can slowly be weaned I.e 1 to 1 down to 1 to 3
What effect does IABP in diastole
Ballon inflates in diastole
This causes increase in diastolic blood pressure, increase in coronary blood flow and increase in myocardial oxygen delivery.
What effects of IABP in systole
IABP deflates in systole Reduces SVR Reduces systolic blood pressure Reduces LV workload Reduces myocardial oxygen demand
Indications of IABP
Cardiogenic shock Intractable angina Acute MI undergoing PTCA Reduced CO after cardiopulmonary bypass Ischaemic VSD Bridge to transplant
Contraindications to IABP
absolute Contraindications to IABP
Aortic regurgitation
Relation contraindications to IABP include Aortic aneurysms Severe peripheral vascular disease Uncontrolled coagulopathy Uncontrolled sepsis Irreversible or terminal disease
Complications of IABP
Aortic /iliac dissection Renal ischaemia Spinal cord ischaemia Thromboembolism Limb or distal ischaemia CVA Bleeding
Act volume and temp
Act 2ml and is incubated at 37 degrees
Effects of drugs of HPV
Volatiles and direct vasodilator inhibit HPV
Vasoconstrictors ie norad prefentially constrict vascular beds that have normal oxygen tensions - indirectly inhibits HPV
Ketamine fentanyl thio propofol no effect on HPV
Purpose of bypass
Bloodless field
Mainta8n oxygenation
Adverse effects CPB
Haemodilutiin (minimise circuit and prime volume)
Consumption coagulation factors (herparin)
Roller pump haemolysis(?centrifugal pump)
Activation leukocytes and d base balance (leucocyte filter)
Unctrolled blood loss (cell salvage)
Air embolism (vented blood filters)
Centrifugal and roller pumps which is non occlusive
Centrifugal non occlusive and blood can go in either direction.
Preload and afterload dependent
oxygenation in CPB
Membrane oxygenation
Other types disc
Bubble
Minimal extracorpeal circulation aims to reduce prime volume with suction blood separation - how
Lack of reservoir
Lack of cardio time Suction
Closed circuit and involves little or no blood air contact
Reduced haemodilution and coagulation cascade
Pre operative assesment of lung resection
Clinical ie more than 4 mets
Pulmonary function tests ie fev1 more than 1.5l in lobectomy and 2l pneumonectomy
Post op predicted values fev 1 and dlco more than 40%
Functional test ie 6minute walk test more than 400 yards
Cpex at more than 11 and vo2 max less than 15
Management hypoxaemia in OLV
Fio2 to 100 Check ventilator and breathing apparatus Check DLT position Peep to dependent lung CPAP to top lung Intermittent two lung ventilation Clamp PA
Primary and secondary causes of MR
Primary causes MR rheumatic heart and MVP
Secondary causes ischaemia and dilated cardiomyopathy
Cause of SOB in MR
Regurgitation blood in left atrium Increases LAP Pulmonary congestion Pulmonary hypertension Also get effects of AF
Pharm agents in MR
Ace I
Diretics
Drugs for AF
Anticoagulation
Investigations in mr
Echo
ECG
CXR
BNP
Haemodynamic goals in MR
Full fast forward
Adequate preload
Fast normal hr 80 100
Low svr
Low pvr
