Truncus arteriosus is a congenital cardiovascular anomaly characterized by a single arterial vessel (truncus) with one valve arising from the heart. The truncus overrides a large perimembranous ventricular septal defect and receives mixed blood from both ventricles and supplies blood to the pulmonary, systemic, and coronary circulation, the ratio of the bloodflow vary according to the different vascular resistances. The anomaly is divided into four types according to Collett and Edwards classification on the basis of the origin of the pulmonary arteries from the truncal artery. In truncus, the goal is to balance the circulation to obtain QP:QS = 1 to maintain reasonable oxygen saturation as well as adequate organ perfusion. Careful titration of anesthetic agents and careful monitoring of their hemodynamic effects and appropriate measures to adjust pulmonary (PVR) and systemic vascular (SVR) resistances and cardiac performance are probably more important than the selection of a particular anesthetic agent. Postoperatively, low cardiac output can be expected because of high PVR and right ventricular failure. High PVR, both sustained and paroxysmal, should be anticipated. Pulmonary hypertensive crisis presents as low cardiac output and right ventricular failure. Avoidance of these potentially fatal events is essential to decrease the mortality and morbidity associated with repair. Events that trigger a hypertensive crisis, such as hypoxia, hypercapnia, acidosis, pain, airway stimulation, and left ventricular failure, must be avoided.
Intraoperative Doppler tissue imaging with pulsed wave Doppler is a rapid method to determine the direction, timing, and velocity of regional longitudinal myocardial motion and quantify systolic and diastolic function. Although DTI provides regional measurements, sampling from different sites will help compensate for any differences, facilitating the evaluation of global EF and diastolic function and the calculation of filling pressures. Repeated DTI observations in the same patient enable the detection of regional ischemia, and the appearance or detection of postsystolic shortening is a sensitive index of ischemic but viable myocardium. DTI has also been used to detect subclinical ventricular dysfunction in asymptomatic patients with valvular disease and differentiate physiologic from pathologic hypertrophy and distinguish constrictive pericarditis from cardiomyopathy.