We read with great interest the Case Scenario on hypoxemia during one-lung ventilation (OLV) reported by Rozéet al. ,1and we would like to add some comments on pharmacological treatment.

First, the title of the section, “Pharmacological treatment to limit hypoxic pulmonary vasoconstriction,” could, in our opinion, lead to confusion. Almitrine does not limit hypoxic pulmonary vasoconstriction but enhances this mechanism in nonventilated areas. Inhaled nitric oxide can inhibit hypoxic pulmonary vasoconstriction in patients with chronic obstructive pulmonary disease breathing room air2; however, during OLV this gas vasodilates ventilated lung areas, shifting the pulmonary blood flow toward these zones without modifying hypoxic pulmonary vasoconstriction.3 

Regarding the use of inhaled nitric oxide, a European board of experts on this topic concluded that there is no evidence to support the routine use of inhaled nitric oxide for the prevention or reversal of hypoxemia during OLV, although some patients with severe hypoxemia may benefit from this drug.4On the other hand, the text suggests that inhaled nitric oxide improves hypoxemia only when it is used with positive end-expiratory pressure, but it has also been useful when administered without positive end-expiratory pressure in patients with severe hypoxemia.5 

Concerning almitrine, the hemodynamic effects on pulmonary circulation are dose-related,6,7and pulmonary hypertension is not expected if a low-dose combined with inhaled nitric oxide is used during OLV.6Peripheral neuropathy related to almitrine has been observed in patients who received this drug for several months, usually with complete recovery,8and is related to high plasma concentrations of almitrine (400 ng/ml).9However, when low-dose almitrine is administered for a short time its plasma concentration is less than the concentration seen with long-term therapy6,7and returns to values close to zero within 12 h after cessation of the infusion.7 

Almitrine and inhaled nitric should not be used routinely. Nevertheless, they can dramatically improve oxygenation6,10,11and thus might be considered as alternative treatments when other strategies fail to improve hypoxemia during OLV.

*Hospital del Mar, Institut Municipal d'Investigació Mèdica, Universitat Autònoma de Barcelona, Barcelona, Spain. lgallart@parcdesalutmar.cat

1.
Rozé H, Lafargue M, Ouattara A: Case scenario: Management of intraoperative hypoxemia during one-lung ventilation. Anesthesiology 2011; 114:167–74
2.
Barberà JA, Roger N, Roca J, Rovira I, Higenbottam TW, Rodriguez-Roisin R: Worsening of pulmonary gas exchange with nitric oxide inhalation in chronic obstructive pulmonary disease. Lancet 1996; 347:436–40
3.
Gallart L, Rouby JJ, Puig MM: [Pharmacologic treatment of hypoxemia in adult respiratory distress syndrome]. Rev Esp Anestesiol Reanim 1997; 44:273–83
4.
Germann P, Braschi A, Della Rocca G, Dinh-Xuan AT, Falke K, Frostell C, Gustafsson LE, Hervé P, Jolliet P, Kaisers U, Litvan H, Macrae DJ, Maggiorini M, Marczin N, Mueller B, Payen D, Ranucci M, Schranz D, Zimmermann R, Ullrich R: Inhaled nitric oxide therapy in adults: European expert recommendations. Intensive Care Med 2005; 31:1029–41
5.
Rocca GD, Passariello M, Coccia C, Costa MG, Di Marco P, Venuta F, Rendina EA, Pietropaoli P: Inhaled nitric oxide administration during one-lung ventilation in patients undergoing thoracic surgery. J Cardiothorac Vasc Anesth 2001; 15:218–23
6.
Silva-Costa-Gomes T, Gallart L, Vallès J, Trillo L, Minguella J, Puig MM: Low- vs  high-dose almitrine combined with nitric oxide to prevent hypoxia during open-chest one-lung ventilation. Br J Anaesth 2005; 95:410–6
7.
Gallart L, Lu Q, Puybasset L, Umamaheswara Rao GS, Coriat P, Rouby JJ: Intravenous almitrine combined with inhaled nitric oxide for acute respiratory distress syndrome. The NO Almitrine Study Group. Am J Respir Crit Care Med 1998; 158:1770–7
8.
Bouche P, Lacomblez L, Leger JM, Chaunu MP, Ratinahirana H, Brunet P, Hauw JJ, Cathala HP, Laplane D: Peripheral neuropathies during treatment with almitrine: Report of 46 cases. J Neurol 1989; 236:29–33
9.
Watanabe S, Kanner RE, Cutillo AG, Menlove RL, Bachand RT Jr, Szalkowski MB, Renzetti AD Jr: Long-term effect of almitrine bismesylate in patients with hypoxemic chronic obstructive pulmonary disease. Am Rev Respir Dis 1989;140:1269–73
10.
Dalibon N, Moutafis M, Liu N, Law-Koune JD, Monsel S, Fischler M: Treatment of hypoxemia during one-lung ventilation using intravenous almitrine. Anesth Analg 2004; 98:590–4
11.
Moutafis M, Liu N, Dalibon N, Kuhlman G, Ducros L, Castelain MH, Fischler M: The effects of inhaled nitric oxide and its combination with intravenous almitrine on Pao2during one-lung ventilation in patients undergoing thoracoscopic procedures. Anesth Analg 1997; 85:1130–5