Table 3.
Etiology and investigation of post-cardiopulmonary bypass ventricular dysfunction
| Cause Investigation | Finding | |
|---|---|---|
| General | ||
| Exacerbation of preoperative ventricular dysfunction with relative intolerance to cardioplegic asystolic, hypoxic arrest | TOE | Global or regional wall motion abnormality |
| Reperfusion injury | TOE | Global wall motion abnormality |
| Inadequate myocardial protection (underlying coronary anatomy, route of cardioplegia, type of cardioplegia) | TOE | Global wall motion abnormality |
| Case/patient specific | ||
| Ischaemia/infarction | ||
| Vessel spasm (native coronaries, internal mammary artery) | ECG, TOE, graft flow | ECG changes, regional wall motion abnormality, poor graft flow |
| Emboli (air, clot, particulate matter) | ECG, TOE, graft flow | ECG changes, regional wall motion abnormality, poor graft flow |
| Technical graft anastomotic tissues | ECG, TOE, graft flow | ECG changes, regional wall motion abnormality, poor graft flow |
| Kink/clotting of bypass grafts, native vessels | ECG, TOE, graft flow, inspection | ECG changes, regional wall motion abnormality, poor graft flow |
| Incomplete revascularization | ||
| Non-graftable vessels | ||
| Known intrinsic disease | ||
| Metabolic | ||
| Hypoxia, hypercarbia | ABG, electrolytes, check ventilation | |
| Hypokalemia, hyperkalemia | Electrolytes | |
| Uncorrected pathology | ||
| Hypertrophic cardiomyopathy | TOE | Abnormal outflow gradient, SAM |
| Valve gradients | TOE | Abnormal valve gradient |
| Shunts | TOE | Abnormal Doppler jet |
| Mechanical issues | ||
| Prosthetic valve function | TOE | Poor leaflet motion, abnormal gradient |
| Intracardiac shunt (ASD, VSD) | TOE | Abnormal Doppler jet |
| Conduction issues | ||
| Bradycardia | ECG | Heart rate less than 60 |
| Atrioventricular dissociation | ECG | Third degree heart block |
| Atrial fibrillation | ECG, ABG, electrolytes | Hypoxia, electrolyte abnormality |
| Ventricular arrhythmias | ECG, ABG, electrolytes | Hypoxia, electrolyte abnormality |
| Vasodilation | Transpulmonary thermodilation, Swan-Ganz monitoring | Decreased systemic vascular resistance |
| Hypovolemia | Stroke volume monitoring | Decreased stroke volume, increased SVV |
| Pulmonary hypertension | ||
| Pre-existing elevated pulmonary pressures, hypoxia, hypercarbia, fluid overload | ABG | Elevated pulmonary artery pressures, hypoxia, hypercarbia, RV distention |
| Right ventricular failure | ||
| Elevated pulmonary pressures, inadequate myocardial protection, emboli to native or bypass circulation, fluid overload | Swan-Ganz monitoring, ABG, TOE | RV distention, poor RV wall motion, elevated pulmonary artery pressure, elevated central venous pressure |
ABG = arterial blood gas; ASD, atrial septic defect; ECG, electrocardiogram, RV, right ventricle, SAM, systolic anterior motion of mitral valve leaflet; SVV, stoke volume variation; TOE, transoesophageal echocardiography; VSD, ventricular septal defect. Data taken from [80].