Sudden hypoxemia after uneventful laparoscopic cholecystectomy: another form of SAM presentation

Abstract

Background: Perioperative dynamic left ventricular outflow obstruction associated with systolic anterior motion of the mitral valve is well recognized as a cause for unexplained sudden hypotension in perioperative settings, even without underlying heart diseases such as hypertrophic obstructive cardiomyopathy. We treated a patient who experienced sudden hypoxemia without severe hypotension during emergence from anesthesia after an uneventful laparoscopic cholecystectomy.

Case presentation: A 65-year-old female patient with a history of hypertension presented a sudden decrease in oxygen saturation to 80% after an uneventful cholecystectomy. Although a portable chest radiograph showed bilateral hilar pulmonary infiltrates consistent with pulmonary edema, we explored the underlying cause, i.e., systolic anterior motion of the mitral valve and left ventricular outflow tract obstruction with bedside transthoracic echocardiography. We speculate that dynamic mitral regurgitation resulted in pulmonary edema and, thereby, hypoxemia in this case without severe hypotension.

Conclusions: Careful bedside examination with transthoracic echocardiography was useful in making diagnosis and in guiding appropriate therapy for this patient. Clinicians should be aware that systolic anterior motion of the mitral valve may present as unexplained sudden hypoxemia in the perioperative setting.

Figure 1

Portable chest radiograph. There were bilateral hilar pulmonary infiltrates, but the periphery of the lungs was relatively spared. Cardiac silhouette was not enlarged. There was air in the stomach.

Figure 2

Bedside transthoracic echocardiography with color-flow Doppler mapping in the post-anesthesia care unit (left parasternal long axis view). Slight mosaic flow signals in the left ventricular outflow tract was noted on colorflow Doppler mapping. LA = left atrium; LV = left ventricle; LVOT; left ventricular outflow tract; Ao = aorta.

Figure 3

Bedside transthoracic echocardiography with color-flow Doppler mapping in the post-anesthesia care unit after sublingular nitrate (left parasternal long axis view). Significant mitral regurgitation jet in the posterior direction (arrow)and mosaic pattern left ventricular outflow (arrow head) appeared.

Figure 4

Cardiac MRI obtained 4 days after surgery. It revealed systolic anterior motion (arrow). There were no abnormalities in global shape, size, and systolic function of the left ventricle, except for some protrusion of the basal interventricular septum towards the left ventricular outflow tract. LA = left atrium; LV = left ventricle; Ao = aorta.