Increased Alveolar Damage after Mechanical Ventilation in a Porcine Model of Thoracic Surgery

• Objective: Mechanical stress during one-lung ventilation (OLV) results in lung injury. This experiment compares effects of mechanical ventilation, OLV and surgical manipulation on diffuse alveolar damage (DAD) after application of different anesthetic regimes. Design: Prospective, randomized, controlled, blinded animal experiment. Setting: University hospital. Objects: Twenty-one piglets. Interventions: Animals (27.5kg) were randomized into four 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 induction of anesthesia. Lung tissue samples were analyzed to obtain reference values for alveolar damage. TLV pigs underwent standard TLV (VT=10ml/kg, FIO2=0.40, PEEP=5cmH2O). In OLV pigs, after lung separation by a bronchial blocker, OLV (VT=10ml/kg) and thoracic surgery were performed. After the procedure the pigs were killed. Lung tissue samples were harvested for histological examination. Lung injury was quantified by DAD score; sequestration of leukocytes was assessed by recruitment of CD45+-cells into the lungs. Main Results: TLV resulted in increased DAD scores in both lungs (TLV vs. SB: 6.9 vs. 2.7; p<0.05); the number of CD45+-cells was not increased (TLV vs. SB: 8.7 vs. 5.0 cells/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 vs. desflurane: CD45+-cells/view: 13.5 vs. 11.3). Conclusions: 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.

Nyckelord

One-Lung Ventilation

Open Thoracic Surgery

Ventilator-Induced Lung Injury

Diffuse Alveolar Damage

Pulmonary Leukocyte Recruitment

General Anesthesia

MEDICINE

MEDICIN

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