THE EFFECTS OF INHALED NITRIC-OXIDE AND ITS COMBINATION WITH INTRAVENOUS ALMITRINE ON PAO2 DURING ONE-LUNG VENTILATION IN PATIENTS UNDERGOING THORACOSCOPIC PROCEDURES

The aim of this study was to assess whether hypoxemia during one-lung ventilation (OLV) can be prevented by inhaled nitric oxide (NO) (Part I) or by its combination with intravenous (IV) almitrine (Part II) in 40 patients undergoing thoracoscopic procedures. In Part I, 20 patient s were divided into two groups: one received O-2 (Group 1) and one rec eived O-2/NO (Group 2). In Part II, 20 patients were divided into two groups: one received O-2 (Group 3) and one received O-2/NO/almitrine ( Group 4). In Groups 2 and 4, NO (20 ppm) was administered during the e ntire period of OLV, and almitrine was continuously infused (16 mu g.k g(-1).min(-1)) in Group 4. Arterial blood gases were measured during t wo-lung ventilation with patients in the supine position, after positi oning in the lateral decubitus position, and then every 5 min for a 30 -min period during OLV. During OLV, Pao(2) values decreased similarly in Groups 1 and 2. After 30 min of OLV, the mean Pao(2) values in Grou ps 1 and 2 were 132+/-14 mm Hg (mean+/-sem) and 149+/-27 mm Hg (not si gnificant [NS]), and the Pao(2) value was less than 100 mm Hg in four patients in Group 1 and five patients in Group 2. Pao(2) values were g reater in Group 4 than in Group 3 after 15 and 30 min of OLV. After 30 min of OLV, the mean Pao(2) values were 146+/-16 mm Hg in Group 3 and 408+/-33 mm Hg in Group 4 (P < 0.001). Pao(2) was less than 100 mm Hg during OLV (NS) in four patients in Group 3 and in no patient in Grou p 4. We conclude that NO inhalation alone has no effect on Pao(2) evol ution during OLV, although its combination with IV almitrine limits th e decrease of Pao(2) during OLV. This beneficial effect of NO/almitrin e could be attributed to an improvement in ventilation-perfusion relat ionships. Implications: Decrease in oxygenation during one-lung ventil ation is quite common. Our study showed that inhaled nitric oxide alon e did not influence Pao(2) evolution. We then tried adding intravenous almitrine to nitric oxide with amazingly good results on Pao(2). This nonventilatory technique should be of great use during special thorac ic acts, such as thoracoscopic procedures.