Unexpected Increase in Arterial to End-Tidal CO₂Gradient in a Child Undergoing Embolization of MAPCAs

A 17-month-old infant with multiple aorto-pulmonary collateral arteries (MAPCAs) and pulmonary hypertension presented for diagnostic catheterization. On the day of the procedure, the infant was asymptomatic with oxygen saturation in the 90’s on 1.0 L/min O2 nasal cannula. His parents denied any recent illness. During the procedure, one coil was inadvertently embolized into the right lung resulting in markedly increased pulmonary artery pressures. The Pa-etCO2 gradient increased to 25 mmHg from a baseline of 2 mmHg. Therapy was initiated to reduce the PaCO2. The patient could not be weaned from mechanical ventilation due to elevated PA pressures.

Inhaled nitric oxide as a salvage therapy for refractory hypoxemia in the post-transplantation period of hepatopulmonary syndrome:An explorative report of three cases

Liver transplantation(LT)is the only effective treatment for hepatopulmonary syndrome(HPS).Moreover,perioperative refractory hypoxemia(pRH)is a prevalent life-threatening condition and has extremely limited treatment options.Here,we report three patients with HPS who experienced pRH after LT and were consecutively treated with different salvage therapies,ephedrine inhalation,intravenous use of methylene blue with nitric oxide(NO)inhalation,and NO inhalation alone.The results showed that unresolved severe hypoxia may induce fatal morbidity such as early biliary leakage and acute kidney injury.Early initiation of NO inhalation,rather than ephedrine,can significantly improve oxygenation in patients with pRH and may help prevent hypoxia-related complications.Therefore,based on the response to these exploratory salvage treatments,we further demonstrate the unique ventilation-perfusion mismatch pathophysiology in specific lung regions during pRH in HPS.We propose that early inhalation of NO is an important treatment option to rescue severe hypoxia in patients with HPS during the perioperative period of LT.

Using optical coherence tomography to detect peripheral pulmonary thrombi

Background Optical coherence tomography （OCT） is a new imaging technique capable of obtaining high-resolution intravascular images of small vessels and has been widely used in interventional cardiology. However, application of OCT in peripheral pulmonary arteries in patients has been seldom documented. Methods Three patients who were highly suspected peripheral pulmonary arteries thrombi and had undergone CT pulmonary angiography but tested negative for thrombi in peripheral pulmonary arteries were enrolled. Subsequently, OCT imaging was performed in peripheral pulmonary arteries. The patients received more than three-month anticoagulative treatment if thrombi were detected by OCT. Thereafter, OCT re-evaluation of the thrombolized blood vessels detected earlier was performed. The changes of thrombi before and after anticoagulative treatment were compared. Results Three patients underwent OCT imaging of peripheral pulmonary arteries. Thrombi were found in most of imaged vessels in these patients. Red and white thrombi can be differentiated, according to features of the thrombus on OCT images. After anticoagulation treatment, these patients＇ symptoms and hypoxemia improved. Repeated OCT imaging showed that most thrombi disappeared or became smaller. Conclusion OCT may be used as a potential tool for detecting peripheral pulmonary artery thrombi and differentiating red thrombi from white ones.