Isoflurane Anesthesia and Arterial Oxygenation during One-lung Ventilation

An anesthesiologist's guide to hypoxic pulmonary vasoconstriction: implications for managing single-lung anesthesia and atelectasis

“…The relative lack of effect of propofol and fentanyl on HPV is fairly consistent in the literature (Table 1). During single-lung ventilation, HPV drops the blood flow to the atelectatic lung by 50% [69]. In single-lung anesthesia in canines, 1 MAC isoflurane decreases HPV [70].…”

Arterial oxygenation and one-lung anesthesia

“…It is also noteworthy that, from 1970 to 2003, the reported incidence of arterial hypoxemia during OLA decreased from 25% [15] to less than 1% [16]. One may speculate that the effect of the (newer) inhalation anesthetic agents (IAAs) on hypoxic pulmonary vasoconstriction (HPV) are unimportant [9,17]. An alternative explanation may be that different anesthetic techniques variably affect the VO 2 /Qt ratio and circulatory efficiency, which will exert an important influence on arterial oxygenation during OLA.…”

“…(4) Mixed venous oxygen tension affects the stimulus oxygen tension responsible for initiation of HPV. An inefficient circulation with a low mixed venous oxygen tension will promote HPV [43,44], especially in ventilated areas of the lung with low ventilation perfusion units [17,30,43]. Conversely, increasing cardiac output and circulatory efficiency will increase mixed venous oxygen tension: an increased mixed venous oxygen tension has been shown to inhibit HPV [43].…”

One-lung flooding for video-assisted thoracoscopic surgery in animal experiments on pigs — oxygenation and intrapulmonary shunt

“…The effect of the volatiles is complex: a combination of depressed hypoxic pulmonary vasoconstriction influencing mixed venous saturation, and impaired contractility of the myocardium affecting cardiac output. Because of the complex action of isoflurane, clinically relevant dosages are not expected to significantly reduce PaO 2 [2].…”