ABSTRACT: The increased tidal volume (V(T)) applied to the ventilated lung during one-lung ventilation (OLV) enhances cyclic alveolar recruitment and mechanical stress. It is unknown whether alveolar recruitment maneuvers (ARMs) and reduced V(T) may influence tidal recruitment and lung density. Therefore, the effects of ARM and OLV with different V(T) on pulmonary gas/tissue distribution are examined.
Eight anesthetized piglets were mechanically ventilated (V(T) = 10 ml/kg). A defined ARM was applied to the whole lung (40 cm H(2)O for 10 s). Spiral computed tomographic lung scans were acquired before and after ARM. Thereafter, the lungs were separated with an endobronchial blocker. The pigs were randomized to receive OLV in the dependent lung with a V(T) of either 5 or 10 ml/kg. Computed tomography was repeated during and after OLV. The voxels were categorized by density intervals (i.e., atelectasis, poorly aerated, normally aerated, or overaerated). Tidal recruitment was defined as the addition of gas to collapsed lung regions.
The dependent lung contained atelectatic (56 ± 10 ml), poorly aerated (183 ± 10 ml), and normally aerated (187 ± 29 ml) regions before ARM. After ARM, lung volume and aeration increased (426 ± 35 vs. 526 ± 69 ml). Respiratory compliance enhanced, and tidal recruitment decreased (95% vs. 79% of the whole end-expiratory lung volume). OLV with 10 ml/kg further increased aeration (atelectasis, 15 ± 2 ml; poorly aerated, 94 ± 24 ml; normally aerated, 580 ± 98 ml) and tidal recruitment (81% of the dependent lung). OLV with 5 ml/kg did not affect tidal recruitment or lung density distribution. (Data are given as mean ± SD.)
The ARM improves aeration and respiratory mechanics. In contrast to OLV with high V(T), OLV with reduced V(T) does not reinforce tidal recruitment, indicating decreased mechanical stress.
Anesthesiology 03/2011; 114(5):1025-35. · 5.36 Impact Factor
ABSTRACT: One-lung ventilation (OLV) results in alveolar proinflammatory effects, whereas their extent may depend on administration of anesthetic drugs. The current study evaluates the effects of different volatile anesthetics compared with an intravenous anesthetic and the relationship between pulmonary and systemic inflammation in patients undergoing open thoracic surgery.
Sixty-three patients scheduled for elective open thoracic surgery were randomized to receive anesthesia with 4 mg · kg⁻¹ · h⁻¹ propofol (n = 21), 1 minimum alveolar concentration desflurane (n = 21), or 1 minimum alveolar concentration sevoflurane (n = 21). Analgesia was provided by remifentanil (0.25 μg · kg⁻¹ · min⁻¹). After intubation, all patients received pressure-controlled mechanical ventilation with a tidal volume of approximately 7 ml · kg ideal body weight, a peak airway pressure lower than 30 cm H₂O, a respiratory rate adjusted to a Paco2 of 40 mmHg, and a fraction of inspired oxygen lower than 0.8 during OLV. Fiberoptic bronchoalveolar lavage of the ventilated lung was performed immediately after intubation and after surgery. The expression of inflammatory cytokines was determined in the lavage fluids and serum samples by multiplexed bead-based immunoassays.
Proinflammatory cytokines increased in the ventilated lung after OLV. Mediator release was more enhanced during propofol anesthesia compared with desflurane or sevoflurane administration. For tumor necrosis factor-α, the values were as follows: propofol, 5.7 (8.6); desflurane, 1.6 (0.6); and sevoflurane, 1.6 (0.7). For interleukin-8, the values were as follows: propofol, 924 (1680); desflurane, 390 (813); and sevoflurane, 412 (410). (Values are given as median [interquartile range] pg · ml⁻¹). Interleukin-1β was similarly reduced during volatile anesthesia. The postoperative serum interleukin-6 concentration was increased in all patients, whereas the systemic proinflammatory response was negligible.
OLV increases the alveolar concentrations of proinflammatory mediators in the ventilated lung. Both desflurane and sevoflurane suppress the local alveolar, but not the systemic, inflammatory responses to OLV and thoracic surgery.
Anesthesiology 03/2011; 115(1):65-74. · 5.36 Impact Factor
ABSTRACT: Mechanical stress during one-lung ventilation (OLV) results in lung injury. This study compared the effects of mechanical ventilation, OLV, and surgical manipulation on diffuse alveolar damage (DAD) after application of different anesthetic regimens.
Prospective, randomized, controlled, blinded animal experiment.
Animals (27.5 kg) were randomized into 4 groups: spontaneous breathing (SB, n = 3), two-lung ventilation (TLV, n = 6), OLV during desflurane (n = 6), and propofol anesthesia (n = 6). SB pigs were killed after the induction of anesthesia. Lung tissue samples were analyzed to obtain reference values for alveolar damage. TLV pigs underwent standard TLV (tidal volumes [V(T)] = 10 mL/kg, F(I)O(2) = 0.40, positive end-expiratory pressure = 5 cmH(2)O). In OLV pigs, after lung separation by a bronchial blocker, OLV (V(T) = 10 mL/kg) and thoracic surgery were performed. After the procedure, the pigs were killed. Lung tissue samples were harvested for histologic examination. Lung injury was quantified by DAD score; sequestration of leukocytes was assessed by the recruitment of CD45(+) cells into the lungs.
TLV resulted in increased DAD scores in both lungs (TLV v SB: 6.9 v 2.7, p < 0.05); the number of CD45(+) cells was not increased (TLV v SB: 8.7 v 5.0 cells per view). OLV and surgical manipulation increased DAD and leukocyte sequestration without differences between the ventilated and manipulated lungs. Leukocyte recruitment was not differently affected by the anesthetic regimen (propofol v desflurane: CD45(+) cells per view: 13.5 v 11.3).
TLV resulted in increased DAD scores in the lungs as compared with SB. OLV and thoracic surgery further increased lung injury and leukocyte recruitment independently of the administration of propofol or desflurane anesthesia.
Journal of cardiothoracic and vascular anesthesia 12/2009; 24(4):617-23. · 1.06 Impact Factor