Cardiac Output

Transoesophageal echocardiography helps assess balloon-pump suitability and positioning, choose appropriate extracorporeal membrane oxygenation support and identify complications including recirculation, left ventricular distension, intracardiac stasis and postoperative tamponade.

Transoesophageal echocardiography guides ventricular assist device implantation and troubleshooting, using ventricular filling, septal position, valve function and cannula flow to identify inadequate unloading, suction, right ventricular failure, obstruction and incorrect Impella positioning.

Cardiopulmonary bypass deliberately changes circulating volume, temperature, coagulation and myocardial activity; understanding haemodilution, hypothermia, heparin response, cardioplegia, separation from bypass and protamine reversal helps distinguish expected physiology from complications requiring intervention.

Intra-aortic balloon pump support depends on correctly timed diastolic inflation and pre-systolic deflation, with paired pressure traces, urine output and lactate helping identify effective unloading, migration, rupture and failed weaning rather than relying on machine settings alone.

Pre-operative intravenous iron modestly reduces transfusion and may add one day at home by 90 days after cardiac surgery, but the original 30-day outcome is neutral, major complications are unchanged and subgroup findings need cautious interpretation.

Protamine reversal after cardiopulmonary bypass can cause rate-related hypotension, allergic phenomena or catastrophic pulmonary hypertension with right ventricular failure, while excess protamine, heparin rebound and antithrombin-related heparin resistance require different recognition and treatment.

Post-cardiotomy bleeding demands immediate haemostatic resuscitation, assessment for tamponade and early surgical involvement without waiting for thromboelastography, while blood-product choice, platelet trends and the 4Ts score help distinguish coagulopathy from heparin-induced thrombocytopenia.

Cardiac surgery for infective endocarditis requires early team referral, timely optimisation and decisive perioperative troubleshooting. Key issues include molecular testing of operative valve tissue, antithrombin-related heparin resistance, vasoplegia and low cardiac output after bypass.

Modern infective endocarditis often presents as acute healthcare-associated sepsis without classical peripheral signs. Diagnosis depends on several adequately filled pre-antibiotic blood-culture sets, valve- and device-appropriate imaging, and careful distinction of vegetations from common mimics.