A 73-year-old female patient presented for mitral valve replacement and coronary artery bypass grafting secondary to multivessel coronary disease and severe mitral valve regurgitation with moderate stenosis. After bypass, the patient developed refractory hypotension with decreased biventricular volume and elevated central venous pressure (CVP). Transesophageal echocardiography (TEE) was utilized to make the diagnosis of acute intraoperative superior vena cava (SVC) syndrome. The SVC cannulation site was revised, resulting in resolution of the hypotension and a decrease in the CVP. Intraoperative TEE was vital in recognizing, managing, and ultimately repairing the acute intraoperative SVC stenosis.
Vasoplegic syndrome, a possible complication of cardiopulmonary bypass, is a critical state of unregulated systemic vasodilation with decreased vascular resistance and a pathological insensitivity to conventional inotropes and vasoconstrictors. This case demonstrates the use of methylene blue and hydroxocobalamin as medications in the treatment of refractory vasoplegic syndrome in the context of cardiac surgery due to their differences in mechanism of action. A 24-year-old female with history of intravenous drug abuse and hepatitis C infection underwent mitral valve repair for infective endocarditis. Preoperative transesophageal echocardiography showed normal right ventricular function, left ventricular ejection fraction of 65%–75%, and severe mitral regurgitation with vegetation. In order to maintain a mean arterial pressure over 60 mmHg during cardiopulmonary bypass, norepinephrine, epinephrine, and vasopressin infusions were required. Given the patient’s minimal response to these medications, a 1.5 mg/kg bolus of intravenous methylene blue was also given intraoperatively; vasoplegic syndrome remained refractory in the post-cardiopulmonary bypass period. A 5 g dose of intravenous hydroxocobalamin was administered in the intensive care unit postoperatively. Postoperative liver function tests were abnormal, and post-cardiopulmonary bypass transesophageal echocardiography revealed mildly decreased right ventricular function. While in the intensive care unit, the patient was placed on venoarterial extracorporeal membrane oxygenation and underwent therapeutic plasma exchange. Vasopressors were weaned over the course of the next 24 h. The patient was able to be transferred out of the intensive care unit on postoperative day 5. Traditional vasoconstrictors activate signal transduction pathways that lead to myosin phosphorylation. Vasodilatory molecules such as nitric oxide (NO) activate the enzyme soluble guanylyl cyclase (sGC), ultimately leading to the dephosphorylation of myosin. Nitric Oxide Synthase (NOS) can potentially increase NO levels 1000-fold when activated by inflammatory cytokines. Methylene blue is a direct inhibitor of NOS. It also binds and inhibits sGC. Hydroxocobalamin is a direct inhibitor of NO, likely inhibits NOS and may also act through additional mechanisms.
Dextrocardia involves embryologic malformations leading to a right hemithorax heart with rightward apex. Situs inversus encompasses all viscera in mirrored position. A 76-year-old male with dextrocardia with situs inversus presented for coronary artery bypass grafting due to a non-ST elevation myocardial infarction. Management was altered accordingly. Electrocardiography leads and defibrillator pads were reversed. A left internal jugular vein central venous catheter provided direct access to the right atrium. Transesophageal echocardiography confirmation of aortic and venous cannulation required turning the probe right for the right-sided aorta and left for liver visualization, respectively. Proactive surgical and anesthetic management was imperative for the successful and uneventful outcome for this patient.
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