ABSTRACT
UNLABELLED: We present a case of mitral valve (MV) replacement that resulted in multiple complications, as diagnosed by transesophageal echocardiography (TEE), including left ventricular outflow tract obstruction, aortic dissection and left ventricular rupture. We also describe that identification of bleeding originating from the posterior aspect of the heart by the surgical team should trigger a complete TEE evaluation for adequate diagnosis. An 84-year-old woman underwent a MV replacement. Weaning from cardiopulmonary bypass (CPB) revealed a late-peaking gradient of 44 mmHg over the left ventricular outflow tract caused by obstruction from a bioprosthetic strut. After proper surgical correction, TEE evaluation showed a type A aortic dissection that was subsequently repaired. After separation from CPB, the surgical team identified a major bleed that originated from the posterior aspect of the heart. Although the initial suspicion was injury to the atrioventricular groove, a complete TEE evaluation confirmed a left ventricular free wall rupture by showing the dissecting jet using colour-flow Doppler. TEE is an essential component in cardiac surgery for assessment of surgical repair and potential complications. Posterior bleeding should trigger a complete TEE examination with assessment of nearby structures to rule out a life-threatening pathology. Left ventricular free wall rupture can be identified using colour-flow Doppler. LEARNING POINTS: Multiple complications may occur after MVR.TEE is an essential component in the evaluation of surgical repair and its potential associated complications, including LVOT obstruction, aortic dissection and LV rupture.Posterior bleeding, from the region of AV groove, should trigger a complete TEE examination with assessment of nearby structures such as the atria, coronary sinus and myocardium to rule out a life threatening pathology.The diagnosis of a LV rupture can be confirmed with 2-D imaging and colour-flow Doppler demonstrating a dissecting jet through the myocardium.
ABSTRACT
PURPOSE: The purpose of this Continuing Professional Development Module is to review the issues pertinent to one-lung ventilation (OLV) and to propose a management strategy for ventilation before, during, and after lung isolation. PRINCIPAL FINDINGS: The need for optimal lung isolation has increased with the advent of video-assisted thoracoscopic surgery, as surgical exposure is critical for successful surgery. Continuous positive airway pressure applied to the operative lung or intermittent two-lung ventilation should therefore be avoided if possible. Optimal management of OLV should provide adequate oxygenation and also prevent acute lung injury (ALI), the leading cause of death following lung resection. Research conducted in the last decade suggests implementing a protective ventilation strategy during OLV that consists of small tidal volumes based on ideal body weight, routine use of positive end-expiratory pressure, low inspired oxygen fraction, with low peak and plateau airway pressures. High respiratory rates to compensate for low tidal volumes may predispose to significant air trapping during OLV, so permissive hypercapnea is routinely employed. The management of OLV extends into the period of two-lung ventilation, as the period prior to OLV impacts lung collapse, and both the time before and after OLV influence the extent of ALI. Lung re-expansion at the conclusion of OLV is an important component of ensuring adequate ventilation and oxygenation postoperatively but may be harmful to the lung. CONCLUSIONS: Optimal perioperative care of the thoracic patient includes a protective ventilation strategy from intubation to extubation and into the immediate postoperative period. Anesthetic goals include the prevention of perioperative hypoxemia and postoperative ALI.
