Cardiac SSU Flashcards
(19 cards)
What are the goals of pre-operative assessment of a patient presenting for an elective cardiac surgical procedure? What information do you tell the patient and how can you best prepare them for the procedure?
SS_CS 1.3
Goals of Pre-Operative Assessment for Elective Cardiac Surgery
Assess and optimize comorbidities: Identify and manage co-existing conditions (e.g., diabetes, hypertension, renal dysfunction, respiratory disease) to reduce perioperative risk
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Evaluate cardiac status: Determine the severity and stability of cardiac disease (e.g., coronary artery disease, valvular pathology, heart failure), assess left ventricular function, and review recent cardiac events (e.g., MI, arrhythmia)
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Risk stratification: Use validated tools (e.g., ASA, EuroSCORE, STS score) and functional assessments (e.g., exercise tolerance, Duke Activity Status Index, CPET) to estimate perioperative morbidity and mortality risk
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Medication review: Review current medications, especially antiplatelet agents, anticoagulants, and heart failure therapies. Plan perioperative management (e.g., continuation, cessation, bridging)
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Investigations: Ensure up-to-date investigations (FBC, U&E, LFTs, coagulation, crossmatch, ECG, CXR, echocardiography, coronary angiography as indicated)
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Assess other organ function: Evaluate renal, respiratory, hepatic, and neurological function, especially in patients with known or suspected dysfunction
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Plan perioperative management: Develop an individualized plan for anaesthesia, monitoring (e.g., invasive lines, TOE), and postoperative care (e.g., ICU/HDU admission)
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Patient education and consent: Ensure the patient understands the risks, benefits, alternatives, and expected outcomes of surgery and anaesthesia, and obtain informed consent
.Information to Communicate to the Patient
Nature and purpose of the surgery: Explain the indication, expected benefits, and potential alternatives (including non-surgical options)
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Risks and complications: Discuss common, uncommon, and rare risks of surgery and anaesthesia, tailored to the patient’s comorbidities and the planned procedure (e.g., stroke, MI, bleeding, infection, renal failure, death)
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Expected postoperative course: Outline the likely recovery process, including ICU/HDU stay, pain management, mobilisation, and rehabilitation
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Potential need for blood transfusion or additional interventions: Discuss the possibility of transfusion or return to theatre if complications arise
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Impact on quality of life and functional status: Address the expected changes in symptoms, physical activity, and independence post-surgery
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Shared decision-making: Encourage questions, explore the patient’s values and preferences, and support informed, autonomous decision-making
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Best Preparation Strategies
Medical optimization: Treat and stabilize comorbidities (e.g., glycaemic control, blood pressure, pulmonary optimisation, anaemia correction)
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Medication management: Adjust perioperative medications as appropriate (e.g., manage antiplatelets/anticoagulants, continue beta-blockers/statins if indicated)
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Nutritional and functional prehabilitation: Encourage smoking cessation, physical activity, and nutritional support to improve resilience
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Enhanced Recovery After Surgery (ERAS) principles: Minimize fasting, provide carbohydrate loading, and educate on early mobilisation and postoperative expectations
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Preoperative investigations: Complete all necessary tests and ensure results are reviewed and acted upon
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Psychological preparation: Address anxiety, provide written and verbal information, and involve family/support persons as appropriate
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Planning for postoperative care: Anticipate and arrange for appropriate level of postoperative monitoring and support (e.g., ICU/HDU)
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How can you assess left ventricular filling status (preload) during anaesthesia for cardiac surgery? What would you consider the most accurate method and why?
SS_CS 1.4
Key Points
TOE/TEE is the most accurate and informative method for intraoperative LV preload assessment in cardiac surgery. PAC provides valuable haemodynamic data but is less direct and can be misleading in certain cardiac pathologies. CVP and clinical parameters are unreliable for precise preload assessment in this setting.
What would help to differentiate acute mitral valve regurgitation (for example, due to acute ischaemic papillary muscle rupture) from chronic mitral valve regurgitation?
SS_CS 1.4
Bottom line:
Acute MR is a haemodynamic emergency with rapid-onset pulmonary oedema, hypotension, and little/no cardiac chamber enlargement; chronic MR is characterized by gradual symptoms, marked LA/LV dilation, and a classic murmur. Prominent v-waves on PAOP, lack of chamber dilation, and severe pulmonary oedema without cardiomegaly are hallmarks of acute MR.
What are your goals when anaesthetizing a patient for coronary artery grafting and how would you achieve these?
SS_CS 1.7
Opening Summary
Coronary artery bypass grafting (CABG) is a major surgical intervention for patients with significant coronary artery disease, aiming to restore myocardial perfusion and reduce ischaemic risk. Anaesthetic management for CABG is complex, requiring meticulous planning and execution to optimise myocardial protection, maintain haemodynamic stability, and minimise perioperative complications. The anaesthetist must anticipate and manage the physiological changes associated with cardiopulmonary bypass (CPB), myocardial ischaemia, coagulopathy, and the systemic inflammatory response, while also considering patient-specific comorbidities and surgical factors. A multidisciplinary approach, careful monitoring, and proactive management of potential complications are essential to achieving favourable outcomes
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Goals for Each Phase
Preoperative Goals
Optimise comorbidities (cardiac, respiratory, renal, metabolic) Continue essential cardiac medications (beta-blockers, statins, nitrates) Assess and manage anaemia, electrolyte disturbances, and infection risk Patient education and informed consent Multidisciplinary planning (cardiology, surgery, anaesthesia, ICU)
Intraoperative Goals
Maintain myocardial oxygen supply-demand balance Ensure haemodynamic stability (avoid tachycardia, hypotension, hypertension) Provide optimal anaesthesia and analgesia Monitor for and manage ischaemia, arrhythmias, and bleeding Protect organs (brain, kidneys, lungs) Minimise transfusion requirements and coagulopathy Facilitate communication with surgical and perfusion teams
Postoperative Goals
Ensure haemodynamic and respiratory stability Early detection and management of complications (bleeding, low cardiac output, arrhythmias) Effective pain control and early extubation Prevent infection and organ dysfunction Plan for rehabilitation and secondary prevention
Key Anaesthetic Considerations
Monitoring: Invasive arterial BP, central venous access, +/- PA catheter, 5-lead ECG, urine output, temperature, and transoesophageal echocardiography (TOE) as indicated Induction: Slow, controlled to avoid haemodynamic swings; high-dose opioid to blunt sympathetic response Maintenance: Balanced anaesthesia (opioid-based, volatile or TIVA); muscle relaxation; maintain normothermia Myocardial Protection: Close communication for timing of aortic cross-clamp, cardioplegia, and reperfusion; avoid tachycardia and hypotension Haemodynamic Management: Use vasopressors/inotropes as needed; anticipate changes during positioning, CPB initiation/separation, and grafting Coagulation: Antifibrinolytics (e.g., tranexamic acid), cell salvage, and point-of-care coagulation testing Ventilation: Lung-protective strategies; minimize oxygen toxicity and barotrauma Blood Conservation: Minimise haemodilution, use cell salvage, restrict crystalloid Post-CPB: Gradual rewarming, correction of metabolic derangements, careful volume and inotrope management, plan for safe separation from bypass Postoperative Care: Early extubation, vigilant monitoring for complications, effective analgesia, and multidisciplinary handover
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What are your goals when anaesthetizing a patient for valve replacement surgery for a stenotic valve lesion (for example mitral stenosis)? Would there be a difference if the patient had a predominantly regurgitant lesion?
How would the decision to perform coronary artery grafting off pump rather than on pump change your anaesthetic management?
How would you programme the pacemaker for epicardial pacing post cardiac surgery, and what problems might you encounter?
Goals for Each Phase
Preoperative
Identify patients at risk for postoperative conduction disturbances. Ensure temporary pacing equipment and wires are available. Discuss pacing plan with surgical team.
Intraoperative
Place epicardial wires on right atrium and/or ventricle. Test wire function before chest closure. Programme pacemaker as indicated (rate, mode, output, sensitivity). Monitor for arrhythmias during weaning from CPB.
Postoperative
Monitor rhythm and haemodynamics continuously. Adjust pacing parameters as needed. Troubleshoot pacing issues promptly. Remove wires when no longer required (typically within 5–7 days).
Key Anaesthetic Considerations
Anticipate need for pacing in high-risk surgeries (valve, congenital). Ensure wires are functional before leaving theatre. Maintain normothermia, normoxia, and correct electrolytes (especially K+, Mg2+, Ca2+). Avoid drugs that increase pacing threshold (e.g., class I antiarrhythmics). Be aware of EMI from diathermy-use bipolar cautery and asynchronous pacing mode if needed. Be prepared for immediate external pacing or defibrillation if pacing fails. Monitor for signs of infection at wire exit sites. Plan for safe removal of wires (risk of tamponade or bleeding).
Mnemonic: “PACE”
Parameters: Set rate, output, and sensitivity appropriately. Appropriate mode: Choose AAI, VVI, or DDD based on rhythm. Check for capture and sensing. Electrolytes and environment: Correct metabolic derangements, minimize EMI.
In what ways does anaesthesia for a “redo” sternotomy differ from that for a primary sternotomy? What additional problems might the surgeon face and how would you prepare for these and manage them should they arise?
What drugs can you administer during the course of cardiac surgery to manipulate coagulation? What doses do you use and what are the most important side-effects?
How can you monitor coagulation status in the peri-operative period?
What is the process of weaning a patient from the bypass pump? What checks are made prior to separation?
What drugs do you know of that we might use to support the circulation after weaning from bypass? How (what doses) do we use these?
How would you manage heparin resistance and heparin induced thrombocytopaenia?
SS_CS 1.18
Summary: Management of Heparin Resistance and Heparin-Induced Thrombocytopaenia (HIT)
Heparin resistance and HIT are critical perioperative challenges in cardiac anaesthesia, especially during procedures requiring cardiopulmonary bypass (CPB). Heparin resistance is the failure to achieve adequate anticoagulation (typically ACT ≥ 400–480 s) despite standard or escalating heparin doses, often due to antithrombin III (ATIII) deficiency. HIT is an immune-mediated complication of heparin exposure, leading to thrombocytopaenia and paradoxical thrombosis, most commonly occurring 5–10 days after exposure.
Sample Viva Script
Examiner: How would you manage a patient with heparin resistance during cardiac surgery?
Candidate:
Confirm true resistance by checking ACT after appropriate heparin dosing. Exclude technical errors (sampling, administration). Consider antithrombin III deficiency as a cause. Administer ATIII concentrate if available, or fresh frozen plasma (FFP) if not. If still resistant, consider alternative anticoagulation strategies.
Examiner: What if the patient develops heparin-induced thrombocytopaenia?
Candidate:
Immediately cease all heparin products. Avoid platelet transfusions unless there is life-threatening bleeding. Initiate alternative anticoagulation, such as a direct thrombin inhibitor (e.g., bivalirudin or argatroban). Consult haematology for ongoing management and confirm diagnosis with laboratory testing. Monitor for thrombotic complications.
Goals for Each Perioperative Phase
Preoperative
Identify risk factors for heparin resistance (previous heparin exposure, ATIII deficiency). Screen for history of HIT. Plan alternative anticoagulation if needed.
Intraoperative
Monitor ACT closely after heparin administration. Be prepared to supplement ATIII or use FFP. Have protocols for rapid switch to direct thrombin inhibitors if HIT is suspected or confirmed.
Postoperative
Vigilant monitoring for thrombosis or bleeding. Continue alternative anticoagulation if HIT. Liaise with haematology for ongoing care and transition to longer-term anticoagulation.
Key Anaesthetic Considerations
Heparin Resistance:
Ensure correct dosing and administration.
Check for ATIII deficiency; supplement with ATIII concentrate or FFP.
Delay surgery if unable to achieve adequate anticoagulation.
Monitor ACT and coagulation profile frequently.
HIT:
Stop all heparin immediately.
Avoid platelet transfusions unless absolutely necessary.
Use alternative anticoagulants (e.g., bivalirudin, argatroban) for ongoing anticoagulation, including during CPB
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Increased risk of thrombosis; monitor for new thrombotic events.
Avoid low-molecular-weight heparin (LMWH) as cross-reactivity can occur.
Involve haematology early.
Mnemonic
“HIT-STOP”:
Halt heparin Initiate alternative anticoagulant Thrombosis surveillance Supportive care Transfuse platelets only if bleeding Obtain haematology input Prevent further exposure
What are the most important complications of cardiac surgery and what steps can you take as the anaesthetist to mitigate them?
How would you use TOE or TTE to perform a rapid assessment of a patient’s haemodynamic status?
How and why would you use an intra-aortic balloon pump? What are some of the problems you might encounter when using one and how would you solve these?
What issues might you expect to encounter when anaesthetizing a patient for a percutaneous valve procedure
Can you recall any cardiac surgery patients you encountered who you and your consultant thought would have been better served by not having surgery? How was this resolved and do you think that the resolution was satisfactory?
