Venous Air Embolism

Abstract

DefinitionsGas embolism refers to the abnormal presence of gas within the circulatory system. It is a known complication of various surgical, therapeutic, and diagnostic procedures. It can also occur as a result of trauma. Gas embolism may be asymptomatic or may even result in immediate cardiovascular collapse. The type and severity of sequelae depend on the composition and amount of gas, the rate and location of entry, and on patient characteristics such as size, cardiopulmonary reserve, and presence of an intracardiac rightleft communication. An understanding of the etiologies and pathophysiology of gas embolism is important in order to recognize, treat, and, most importantly, prevent this potentially catastrophic complication.Gas enters the circulation when two conditions co-exist: (1) a communication between a gas source and the vascular system, and (2) a pressure gradient that favors gas entry into the vasculature. When the atmosphere is the source of gas, then this condition is termed air embolism. Gas can be entrained into open veins or venous sinuses, insufflated into traumatized vessels, or accidentally infused under pressure through indwelling venous or arterial catheters. Rarely, dissolved gas is released in blood through effervescence caused by rapid re-warming or decompression. 1 Venous (pulmonary) gas embolism (VGE) refers to gas that gains entry into the venous system and causes morbidity via its effects on the right heart and pulmonary vasculature. Systemic (arterial) gas embolism (SGE) results from gas that is propelled by the left heart and embolizes to systemic arterial beds causing ischemia and infarction. Paradoxical gas embolism (PGE) originates in the venous system and gains access to the arterial system through intracardiac defects or the pulmonary circulation.

A Kingdom for a Catholic? Pope Clement VIII, King James VI/I, and the English Succession in International Diplomacy (1592–1605)

“…58 It does not seem that the new FrancoPapal friendship 'isolated Philip II in western Europe': 59 the Pope carefully avoided provoking any rupture or deterioration of the papacy's relations with Spain. 60 This explains to a certain extent why, in late 1600, Spain still believed that the Pope would just follow its lead in the English succession. Clement VIII's independent diplomacy affirmed the position of the papal monarchy as a supranational power in Catholic Europe: papal diplomats did not only mediate effectively between Spain and France for the Peace of Vervins (1598) but also managed to impede a renewal of a large-scale war by negotiating the Peace of Lyons (1601).…”

With a little help from his friends

“…11, detail). 114 In Still life with a tazza, cameo bracelets and other trinkets spill out of a painted box with studied carelessness ( fig. 12).…”