| 1. |
- Kozian, Alf, 1969-, et al.
(författare)
-
Lung computed tomography density distribution in a porcine model of one-lung ventilation
- 2009
-
Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 0007-0912 .- 1471-6771. ; 102:4, s. 551-560
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: One-lung ventilation (OLV) exposes the dependent lung to increased mechanical stress which may affect the postoperative course. This study evaluates regional pulmonary gas/tissue distribution in a porcine model of OLV. METHODS: Nine anaesthetized and mechanically ventilated (V(T)=10 ml kg(-1), FI(O(2))=0.40, PEEP=5 cm H(2)O) pigs were studied. After lung separation by an endobronchial blocker, lateral thoracotomy and OLV were performed in six pigs. Three animals served as controls. Static end-expiratory and end-inspiratory spiral computed tomography (CT) scans were done before, during, and after OLV and at corresponding times in controls. CT images were analysed by defined regions of interest and summarized voxels were classified by defined lung X-ray density intervals (atelectasis, poorly aerated, normally aerated, and overaerated). RESULTS: Dependent lungs contained poorly aerated regions and atelectasis with a significant tidal recruitment during conventional two-lung ventilation (TLV) before OLV (expiration vs inspiration: atelectasis 29% vs 14%; poorly aerated 66% vs 44%; normally aerated 4% vs 41% of the dependent lung volume, P<0.05). During OLV (V(T)=10 ml kg(-1)), cyclic recruitment was increased. The density spectrum of the ventilated lung changed from consolidation to aeration (expiration vs inspiration: atelectasis 10% vs 2%; poorly aerated 71% vs 18%; normally aerated 19% vs 79%, P<0.05). After OLV, increased aeration remained with less atelectasis and poorly aerated regions. Lung density distribution in the non-dependent lung of OLV pigs was unaltered after the period of complete lung collapse. CONCLUSIONS: Cyclic tidal recruitment during OLV in pigs was associated with a persistent increase of aeration in the dependent lung.
|
|
| 2. |
- Kozian, Alf, 1969-, et al.
(författare)
-
One-lung ventilation induces hyperperfusion and alveolar damage in the ventilated lung : an experimental study
- 2008
-
Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 0007-0912 .- 1471-6771. ; 100:4, s. 549-559
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: One-lung ventilation (OLV) increases mechanical stress in the lung and affects ventilation and perfusion (V, Q). There are no data on the effects of OLV on postoperative V/Q matching. Thus, this controlled study evaluates the influence of OLV on V/Q distribution in a pig model using a gamma camera technique [single-photon emission computed tomography (SPECT)] and relates these findings to lung histopathology after OLV. METHODS: Eleven anaesthetized and ventilated pigs (V(T)=10 ml kg(-1), Fio2=0.40, PEEP=5 cm H2O) were studied. After lung separation, OLV and thoracotomy were performed in seven pigs (OLV group). During OLV and in a two-lung ventilation (TLV), control group (n=4) ventilation settings remained unchanged. SPECT with (81m)Kr (ventilation) and (99m)Tc-labelled macro-aggregated albumin (perfusion) was performed before, during, and 90 min after OLV/TLV. Finally, lung tissue samples were harvested and examined for alveolar damage. RESULTS: OLV affected ventilation and haemodynamic variables, but there were no differences between the OLV group and the control group before and after OLV/TLV. SPECT revealed an increase of perfusion in the dependent lung compared with baseline (49-56%), and a corresponding reduction of perfusion (51-44%) in non-dependent lungs after OLV. No perfusion changes were observed in the control group. This resulted in increased low V/Q regions and a shift of V/Q areas to 0.3-0.5 (10(-0.5)-10(-0.3)) in dependent lungs of OLV pigs and was associated with an increased diffuse alveolar damage score. CONCLUSIONS: OLV in pigs results in a substantial V/Q mismatch, hyperperfusion, and alveolar damage in the dependent lung and may thus contribute to gas exchange impairment after thoracic surgery.
|
|
| 3. |
|
|
| 4. |
- Schilling, Thomas, 1966-, et al.
(författare)
-
Effects of propofol and desflurane anaesthesia on the alveolar inflammatory response to one-lung ventilation
- 2007
-
Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 0007-0912 .- 1471-6771. ; 99:3, s. 368-375
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: One-lung ventilation (OLV) induces a pro-inflammatory response including cytokine release and leucocyte recruitment in the ventilated lung. Whether volatile or i.v. anaesthetics differentially modulate the alveolar inflammatory response to OLV is unclear. METHODS: Thirty patients, ASA II or III, undergoing open thoracic surgery were randomized to receive either propofol 4 mg kg(-1) h(-1) (n = 15) or 1 MAC desflurane in air (n = 15) during thoracic surgery. Analgesia was provided by i.v. infusion of remifentanil (0.25 microg kg(-1) min(-1)) in both groups. The patients were mechanically ventilated according to a standard protocol during two-lung ventilation and OLV. Fibre optic bronchoalveolar lavage (BAL) of the ventilated lung was performed before and after OLV and 2 h postoperatively. Alveolar cells, protein, tumour necrosis factor alpha (TNFalpha), interleukin (IL)-8, soluble intercellular adhesion molecule-1 (sICAM), IL10, and polymorphonuclear (PMN) elastase were determined in the BAL fluid. Data were analysed by parametric or non-parametric tests, as indicated. RESULTS: In both groups, an increase in pro-inflammatory markers was found after OLV and 2 h postoperatively; however, the fraction of alveolar granulocytes (median 63.7 vs 31.1%, P < 0.05) was significantly higher in the propofol group compared with the desflurane group. The time courses of alveolar elastase, IL-8, and IL-10 differed between groups, and alveolar TNFalpha (7.4 vs 3.1 pg ml(-1), P < 0.05) and sICAM-1 (52.3 vs 26.3 ng ml(-1), P < 0.05) were significantly higher in the propofol group. CONCLUSIONS: These data indicate that pro-inflammatory reactions during OLV were influenced by the type of general anaesthesia. Different patterns of alveolar cytokines may be a result of increased granulocyte recruitment during propofol anaesthesia.
|
|
| 5. |
- Schilling, Thomas, 1966-
(författare)
-
The Immune Response to One-Lung Ventilation : Clinical and Experimental Studies
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One-lung ventilation (OLV) as an established procedure during thoracic surgery may be injurious in terms of increased mechanical stress characterised by alveolar cell stretch and overdistension, increased cyclic tidal recruitment of alveolar units, compression of alveolar vessels and increased pulmonary vascular resistance. This may result in ventilation-induced lung injury with pro-inflammatory cytokine production, leukocyte recruitment and neutrophil-dependent tissue destruction. Despite the consequences of delivering the whole tidal volume (VT) to only a single lung, relatively high VT are used during OLV to maintain arterial oxygenation and carbon dioxide elimination. However, this may increase mechanical stress in the dependent lung and may aggravate alveolar injury. There is a lack of data on the alveolar immune consequences of OLV. Therefore, the present studies investigate the epithelial damage and pro-inflammatory response induced by mechanical ventilation and OLV. OLV induced pulmonary injury, but alveolar damage in the ventilated lung decreased by reduction of the tidal volume in patients scheduled for thoracic surgery (study I). The use of the volatile anaesthetic desflurane in OLV patients attenuated the OLV-induced alveolar immune response (study II). Furthermore, an experimental model of thoracic surgery was established to investigate the systemic and pulmonary consequences of OLV and thoracic surgery in comparison with the effects of conventional two-lung ventilation and spontaneous breathing. The experimental data indicate that beside the pulmonary immune response volatile anaesthetics have also modulated the plasma concentrations of cytokines during and after OLV (study III). In contrast, OLV and thoracic surgery increased the expression of pro-inflammatory mRNA in BAL cells and lung tissue samples. General anaesthesia did not affect this response (study 4). The results of the present studies indicate that OLV and thoracic surgery may be injurious to the lung tissue to a similar degree. The recruitment and activation of alveolar granulocytes characterise the alveolar damage. The administration of different anaesthetics modulates the activation of alveolar cells, specified by decreased inflammatory mediator release in subjects that receive desflurane anaesthesia, which does not affect the expression of cytokine mRNA in alveolar cells and lung tissue samples.
|
|
| 6. |
- Schilling, Thomas, et al.
(författare)
-
The pulmonary immune effects of mechanical ventilation in patients undergoing thoracic surgery
- 2005
-
Ingår i: Anesthesia and Analgesia. - : International Anesthesia Research Society. - 0003-2999 .- 1526-7598. ; 101:4, s. 957-965
-
Tidskriftsartikel (refereegranskat)abstract
- Mechanical ventilation (MV) may induce an inflammatory alveolar response. One-lung ventilation (OLV) with tidal volumes (Vt) as used during two-lung ventilation is a suggested algorithm but may impose mechanical stress of the dependent lung and potentially aggravate alveolar mediator release. We studied whether ventilation with different Vt modifies pulmonary immune function, hemodynamics, and gas exchange. Thirty-two patients undergoing open thoracic surgery were randomized to receive either MV with Vt = 10 mL/kg (n = 16) or Vt = 5 mL/kg (n = 16) adjusted to normal Pa(CO2) during and after OLV. Fiberoptic bronchoalveolar lavage of the ventilated lung was performed, and cells, protein, tumor necrosis factor (TNF)-alpha, interleukin (IL)-8, soluble intercellular adhesion molecule (sICAM)-1, IL-10, and elastase were determined in the bronchoalveolar lavage. Data were analyzed by parametric or nonparametric tests, as indicated. In all patients, an increase of proinflammatory variables was found. The time courses of intra-alveolar cells, protein, albumin, IL-8, elastase, and IL-10 did not differ between the groups after OLV and postoperatively. TNF-alpha (8.4 versus 5.0 microg/mL) and sICAM-1 (52.7 versus 27.5 microg/mL) concentrations were significantly smaller after OLV with Vt = 5 mL/kg. These results indicate that MV may induce epithelial damage and a proinflammatory response in the ventilated lung. Reduction of tidal volume during OLV may reduce alveolar concentrations of TNF-alpha and of sICAM-1. IMPLICATIONS: Reductions of tidal volume, with subsequently decreased peak airway pressures, may reduce some alveolar inflammatory responses seen with mechanical ventilation.
|
|
| 7. |
- Kozian, Alf, 1969-
(författare)
-
Pathophysiological and Histomorphological Effects of One-Lung Ventilation in the Porcine Lung
- 2009
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Thoracic surgical procedures require partial or complete airway separation and the opportunity to exclude one lung from ventilation (one-lung ventilation, OLV). OLV is commonly associated with profound pathophysiological changes that may affect the postoperative outcome. It is injurious in terms of increased mechanical stress including alveolar cell stretch and overdistension, shear forces secondary to repeated tidal collapse and reopening of alveolar units and compression of alveolar vessels. Ventilation and perfusion distribution may thus be affected during and after OLV. The present studies investigated the influence of OLV on ventilation and perfusion distribution, on the gas/tissue distribution and on the lung histomorphology in a pig model of thoracic surgery.Anaesthetised and mechanically ventilated piglets were examined. The ventilation and perfusion distribution within the lungs was assessed by single photon emission computed tomography. Computed tomography was used to establish the effects of OLV on dependent lung gas/tissue distribution. The pulmonary histopathology of pigs undergoing OLV and thoracic surgery was compared with that of two-lung ventilation (TLV) and spontaneous breathing.OLV induced hyperperfusion and significant V/Q mismatch in the ventilated lung persistent in the postoperative course. It increased cyclic tidal recruitment that was associated with a persistent increase of gas content in the ventilated lung. OLV and thoracic surgery as well resulted in alveolar damage. In the present model of OLV and thoracic surgery, alveolar recruitment manoeuvre (ARM) and protective ventilation approach using low tidal volume preserved the ventilated lung density distribution and did not aggravate cyclic recruitment of alveoli in the ventilated lung.In conclusion, the present model established significant alveolar damage in response to OLV and thoracic surgery. Lung injury could be related to the profound pathophysiological consequences of OLV including hyperperfusion, ventilation/perfusion mismatch and increased tidal recruitment of lung tissue in the dependent, ventilated lung. These mechanisms may contribute to the increased susceptibility for respiratory complications in patients undergoing thoracic surgery. A protective approach including sufficient ARM, application of PEEP, and the use of lower tidal volumes may prevent the ventilated lung from deleterious consequences of OLV.
|
|
| 8. |
- Strang, Christof M., et al.
(författare)
-
Development of atelectasis and arterial to end-tidal PCO2-difference in a porcine model of pneumoperitoneum
- 2009
-
Ingår i: British Journal of Anaesthesia. - : Elsevier BV. - 0007-0912 .- 1471-6771. ; 103:2, s. 298-303
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Intraperitoneal insufflation of carbon dioxide (CO2) may promote collapse of dependent lung regions. The present study was undertaken to study the effects of CO2-pneumoperitoneum (CO2-PP) on atelectasis formation, arterial oxygenation, and arterial to end-tidal PCO2-gradient (Pa-E'(CO2)). METHODS: Fifteen anaesthetized pigs [mean body weight 28 (SD 2) kg] were studied. Spiral computed tomography (CT) scans were obtained for analysis of lung tissue density. In Group 1 (n=5) mechanical ventilation (V(T)=10 ml kg (-1), FI(O2)=0.5) was applied, in Group 2 (n=5) FI(O2) was increased for 30 min to 1.0 and in Group 3 (n=5) negative airway pressure was applied for 20 s in order to enhance development of atelectasis. Cardiopulmonary and CT data were obtained before, 10, and 90 min after induction of CO2-PP at an abdominal pressure of 12 mmHg. RESULTS: Before CO2-PP, in Group 1 non-aerated tissue on CT scans was 1 (1)%, in Group 2 3 (2)% (P<0.05, compared with Group 1), and in Group 3 7 (3)% (P<0.05, compared with Group 1 and Group 2). CO2-PP significantly increased atelectasis in all groups. PaO2/FI(O2) fell and venous admixture ('shunt') increased in proportion to atelectasis during anaesthesia but CO2-PP had a varying effect on PaO2/FI(O2) and shunt. Thus, no correlation was seen between atelectasis and PaO2/FI(O2) or shunt when all data before and during CO2-PP were pooled. Pa-E'(CO2), on the other hand correlated strongly with the amount of atelectasis (r2=0.92). CONCLUSIONS: Development of atelectasis during anaesthesia and PP may be estimated by an increased Pa-E'(CO2).
|
|
