The effects of two lung ventilation, one lung ventilation and alveolar lavage on right ventricular mechanics in a patient have been observed using transoesophageal echocardiography (TOE). Alveolar lavage resulted in additional stresses to those of one lung ventilation (OLV) and the point when these were noted to be resulting in right ventricular changes was used as the signal to terminate the filling phase of a cycle of alveolar lavage. A significant increase in right ventricle afterload occurred on starting OLV. The response to lung lavage was biphasic, initially a further increase in afterload followed by a reduction in preload. Because there was rapid adaptation to these changes, it was felt appropriate to perform sequential lung lavage during the same anaesthetic. In similar circumstances where pulmonary vascular resistance is changed, information obtained from TOE may be used to guide therapy.