The effect of intermittent positive airway pressure to the non-ventilated lung was assessed in 10 patients who
desaturated during one-lung ventilation. Once their saturation fell below 95% they were given a slow inflation of
2 l/min of oxygen into the non-ventilated lung for two seconds. This was repeated every 10 seconds for five minutes
or until the saturation rose to 98%, whichever was sooner. The initial mean SpO2 was 89.3%±4.2%. All 10
patients had an increase in saturation. The mean saturation following intermittent positive airway pressure was
96.5%±1.6% (P <0.0001). Similarly, the mean oxygen tension rose from 67.2±12.8 mmHg to 98.9±19.8 mmHg. Intermittent positive airway pressure should be considered for patients who desaturate while undergoing one-lung ventilation.

Background: Although one-lung ventilation (OLV) has become
an established procedure during thoracic surgery, sparse
data exist about inflammatory alterations in the deflated, reventilated
lung. The aim of this study was to prospectively investigate
the effect of OLV on the pulmonary inflammatory response
and to assess possible immunomodulatory effects of the anesthetics
propofol and sevoflurane.
Methods: Fifty-four adults undergoing thoracic surgery with
OLV were randomly assigned to receive either anesthesia with
intravenously applied propofol or the volatile anesthetic
sevoflurane. A bronchoalveolar lavage was performed before
and after OLV on the lung side undergoing surgery. Inflammatory
mediators (tumor necrosis factor
, interleukin 1, interleukin
6, interleukin 8, monocyte chemoattractant protein 1)
and cells were analyzed in lavage fluid as the primary endpoint.
The clinical outcome determined by postoperative adverse
events was assessed as the secondary endpoint.
Results: The increase of inflammatory mediators on OLV was
significantly less pronounced in the sevoflurane group. No difference
in neutrophil recruitment was found between the
groups. A positive correlation between neutrophils and mediators
was demonstrated in the propofol group, whereas this
correlation was missing in the sevoflurane group. The number
of composite adverse events was significantly lower in the
sevoflurane group.
Conclusions: This prospective, randomized clinical study
suggests an immunomodulatory role for the volatile anesthetic
sevoflurane in patients undergoing OLV for thoracic surgery
with significant reduction of inflammatory mediators and asignificantly better clinical outcome (defined by postoperative adverse events) during sevoflurane anesthesia.

AB BACKGROUND: Collapse of the ipsilateral lung facilitates surgical exposure during thoracic procedures. The use of different gas mixtures during two-lung ventilation (2LV) may improve or impede surgical conditions during subsequent one-lung ventilation (OLV) by increasing or delaying lung collapse. We investigated the effects of three different gas mixtures during 2LV on lung collapse and oxygenation during subsequent OLV: Air/Oxygen (fraction of inspired oxygen [Fio2] = 0.4), Nitrous Oxide/Oxygen (“N2O,” Fio2 = 0.4) and Oxygen (“O2,” Fio2 = 1.0). METHODS: Subjects were randomized into three groups: Air/Oxygen (n = 33), N2O (n = 34) or O2 (n = 33) and received the designated gas mixture during induction and until the start of OLV. Subjects’ lungs in all groups were then ventilated with Fio2 = 1.0 during OLV. The surgeons, who were blinded to the randomization, evaluated the lung deflation using a verbal rating scale at 10 and 20 min after the start of OLV. Serial arterial blood gases were performed before anesthesia induction, during 2LV, and every 5 min, for 30 min, after initiation of OLV. RESULTS: The use of air in the inspired gas mixture during 2LV led to delayed lung deflation during OLV, whereas N2O improved lung collapse. Arterial oxygenation was significantly improved in the O2 group only for the first 10 min of OLV, after which there were no differences in mean Pao2 values among groups. CONCLUSIONS: De-nitrogenation of the lung during 2LV is a useful strategy to improve surgical conditions during OLV. The use of Fio2 1.0 or N2O/O2 (Fio2 0.4) during 2LV did not have an adverse effect on subsequent oxygenation during OLV. (C) 2009 by International Anesthesia Research Society.

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 / matching. Thus, this controlled study evaluates the influence of OLV on / 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 (VT=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 81mKr (ventilation) and 99mTc-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 / regions and a shift of / 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 / mismatch, hyperperfusion, and alveolar damage in the dependent lung and may thus contribute to gas exchange impairment after thoracic surgery.

British Journal of Anaesthesia 2007 99(3):368-375.
T. Schilling1,*, A. Kozian1, M. Kretzschmar1, C. Huth2, T. Welte3, F. Bühling4, G. Hedenstierna5 and T. Hachenberg1

1 Department of Anaesthesiology and Intensive Care Medicine
2 Department of Cardiovascular and Thoracic Surgery, Otto-von-Guericke-University Magdeburg, Germany
3 Department of Pneumology, Hannover Medical School, Germany
4 Institute of Clinical Chemistry, Carl-Thiem-Hospital Cottbus, Germany
5 Department of Clinical Physiology, Uppsala University, Sweden

* Corresponding author: Department of Anaesthesiology and Intensive Care Medicine, Otto-von-Guericke-University, Leipziger Str. 44, D-39120 Magdeburg, Germany. E-mail: thomas.schilling@medizin.uni-magdeburg.de

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 µg 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 (TNF), 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 TNF (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.

Objective: Lung injury induced by one-lung ventilation is rare, but it is acondition that may result in high mortality. This study evaluates the effects ofone-lung ventilation and occlusion time on collapsed and contralateral lungs.Methods: Sprague-Dawley rats were allocated randomly into 7 groups consisting of6 animals each: sham; O1, 1 hour of occlusion/2 hours of re-expansion; C1, 3 hoursof mechanical ventilation control; O2, 2 hours of occlusion/2 hours of re-expansion;C2, 4 hours of mechanical ventilation control; O3, 3 hours of occlusion/2 hours ofre-expansion; and C3, 5 hours of mechanical ventilation control groups. In theocclusion groups, the left lung was collapsed by bronchial occlusion. Malondialdehydeactivity was determined in the blood, and myeloperoxidase and malondialdehydeactivity was determined in the collapsed and contralateral lungs. Lung tissueswere also examined histopathologically.Results: Malondialdehyde and myeloperoxidase levels rose as occlusion durationincreased. This increase was greater in the occlusion groups than that in their owncontrol groups. Increases were significant in the O2 compared with the O1 groups(P .005). Histologically, tissue damage increased as occlusion time rose injury incollapsed and contralateral lungs. Injury was greater in the occlusion groups thaninjury in their own control groups (P .005).Conclusions: Our findings show that biochemical and histopathologic injury occurin collapsed and contralateral lungs in one-lung ventilation, and this injury increasesas occlusion time rises. We believe that occlusion and occlusion time-related injuryshould be borne in mind in the clinic under conditions requiring the application of one-lung ventilation.

Kuzkov, Vsevolod V. MD, PhD; Suborov, Evgeny V. MD; Kirov, Mikhail Y. MD, PhD; Kuklin, Vladimir N. MD, PhD; Sobhkhez, Mehrdad MSci; Johnsen, Solveig MD; Waerhaug, Kristine MD; Bjertnaes, Lars J. MD, PhD

Institution From the Department of Anesthesiology, Institute of Clinical Medicine, University of Tromso, Tromso, Norway (VVK, EVS, MYK, VNK, MS, SJ, KW, LJB); and the Department of Anesthesiology and Intensive Care Medicine, Northern State Medical University, Arkhangelsk, Russian Federation (VVK, EVS, MYK).

Abstract Objective: To compare the single thermodilution and the thermal-dye dilution techniques with postmortem gravimetry for assessment of changes in extravascular lung water after pneumonectomy and to explore the evolution of edema after injurious ventilation of the left lung.

Design: Experimental study.

Setting: University laboratory.

Subjects: A total of 30 sheep weighing 35.6 +/- 4.6 kg. The study included two parts: a pneumonectomy study (n = 18) and an injurious ventilation study (n = 12).

Methods: Sheep were anesthetized and mechanically ventilated with an Fio2 of 0.5, tidal volume of 6 mL/kg, and positive end-expiratory pressure of 2 cm H2O. In the pneumonectomy study, sheep were assigned to right-sided pneumonectomy (n = 7), left-sided pneumonectomy (n = 7), or lateral thoracotomy only (sham operation, n = 4). In the injurious ventilation study, right-sided pneumonectomy was followed by ventilation with a tidal volume of 12 mL/kg and positive end-expiratory pressure of 0 cm H2O (n = 6) or by ventilation with a tidal volume of 6 mL/kg and positive end-expiratory pressure of 2 cm H2O for 4 hrs (n = 6). Volumetric variables, including extravascular lung water index (EVLWI), were measured with single thermodilution (STD; EVLWISTD) and thermal-dye dilution (TDD; EVLWITDD) techniques. We monitored pulmonary hemodynamics and respiratory variables. After the sheep were killed, EVLWI was determined for each lung by gravimetry (EVLWIG).

Results: In total, the study yielded strong correlations of EVLWISTD and EVLWITDD with EVLWIG (n = 30; r = .83 and .94, respectively; p < .0001). After pneumonectomy, both the left- and the right-sided pneumonectomy groups displayed significant decreases in EVLWISTD and EVLWITDD. The injuriously ventilated sheep demonstrated significant increases in EVLWI that were detected by both techniques. The mean biases (+/-2 sd) compared with EVLWIG were 3.0 +/- 2.6 mL/kg for EVLWISTD and 0.4 +/- 1.6 mL/kg for EVLWITDD. Conclusions: After pneumonectomy and injurious ventilation of the left lung, TDD and STD displayed changes in extravascular lung water with acceptable accuracy when compared with postmortem gravimetry. Ventilator-induced lung injury seems to be a crucial mechanism of pulmonary edema after pneumonectomy.

Ozcan PE. Senturk M. Sungur Ulke Z. Toker A. Dilege S. Ozden E. Camci E.
Institution
Department of Anaesthesiology, Istanbul Medical Faculty, Istanbul University, Capa 34093, Istanbul, Turkey.
Title
Effects of thoracic epidural anaesthesia on pulmonary venous admixture and oxygenation during one-lung ventilation.
Source
Acta Anaesthesiologica Scandinavica. 51(8):1117-22, 2007 Sep.

Abstract
BACKGROUND: In this clinical randomized study, the effects of four anaesthesia techniques during one-lung ventilation [total intravenous anesthesia (TIVA) with or without thoracic epidural anaesthesia (TEA) (G-TIVA-TEA and G-TIVA), isoflurane anaesthesia with or without TEA (G-ISO-TEA and G-ISO)] on pulmonary venous admixture (Qs/Qt) and oxygenation (OLV) were investigated. METHODS: In 100 patients (four groups, 25 patients in each) undergoing thoracotomy, a thoracic epidural catheter was inserted pre-operatively. In G-TIVA-TEA and G-ISO-TEA, bupivacaine 0.1% + 0.1 mg/ml morphine was administered intra-operatively (10 ml of first bolus + 7 ml/h infusion). Propofol infusion or isoflurane concentration was adjusted to keep a bispectral index (BIS) of between 40 and 50 in all groups. FiO(2) was 0.8 during OLV and 0.5 before and after OLV. Partial arterial and central venous oxygen pressures (PaO(2) and PvO(2)), arterial and venous oxygen saturations and Qs/Qt values were recorded before, during and after OLV. RESULTS: During OLV, PaO(2) was significantly higher and Qs/QT significantly lower in G-TIVA-TEA and G-TIVA compared with G-ISO-TEA and G-ISO (PaO2: 188 +/- 36; 201 +/- 39; 159 +/- 33; 173 +/- 42 mmHg, respectively; Qs/Qt: 31.2 +/- 7.4; 28.2 +/- 7; 36.7 +/- 7.1; 33.7 +/- 7.7%, respectively). No statistical changes were observed in patients with TEA compared with without TEA in any measurement. CONCLUSION: During OLV, TEA does not significantly affect the oxygenation and Qs/Qt and can be used safely regardless of whether TIVA or inhalation techniques are used.

Unzueta, M Carmen MD, PhD; Casas, J Ignacio MD; Moral, M Victoria MD.
Anesth Analg. 2007 May;104(5):1029-33

From the Department of Anesthesiology, Hospital de Sant Pau, Barcelona, Spain.
Accepted for publication January 15, 2007.
Supported by Departmental resources.
Address correspondence to M. Carmen Unzueta, Sant Antonio Ma Claret 167, Barcelona 08025, Spain. Address e-mail to mcunzueta@telefonica.net.
Abstract
BACKGROUND: Pressure-controlled ventilation (PCV) has been suggested as a tool to improve oxygenation during one-lung ventilation (OLV) for patients undergoing thoracic surgery. In this study we investigated whether PCV results in improved arterial oxygenation compared with volume-controlled ventilation (VCV) during OLV.

METHODS: Fifty-eight patients with good preoperative pulmonary function scheduled for thoracic surgery were prospectively randomized into two groups. Those in group A underwent OLV initially with VCV for 30 min followed by PCV for a similar period of time. Those in group B underwent OLV initially with PCV for 30 min followed by VCV for a similar duration. Airway pressures and arterial blood gases were obtained during OLV at the end of each ventilatory mode.

RESULTS: There were no differences during OLV in arterial oxygenation between VCV (Pao2, 206.1 ± 62.4 mm Hg) and PCV (Pao2, 202.1 ± 56.4 mm Hg; P = 0.534). Peak airway pressure was lower with PCV than with VCV (24.43 ± 3.42 cm H2O vs. 34.16 ± 5.21 cm H2O; P < 0.001). CONCLUSIONS: The use of PCV during OLV does not lead to improved oxygenation during OLV compared with VCV for patients with good preoperative pulmonary function, but PCV did lead to lower peak airway pressures. Further study is needed for patients with severe obstructive or restrictive pulmonary disease.

The majority of studies of Nitric Oxide (NO) during one-lung ventilation over the past five years have shown that NO does not cause a significant increase in the mean PaO2. One recent study(1) shows that among patients with hypoxemia (defined here as PaO2/FiO2 <100) there was an increase in mean arterial oxygenation with NO 40ppm. Examining the data shows that a small minority of hypoxemic patients (approximately 25%)will have a clinically useful increase in PaO2 with NO. Examining the data of previous studies(2) it can be seen in other studies that a few patients with borderline hypoxemia will have an increase in PaO2 with NO. Although this does not make NO a useful therapy for hypoxemia during one-lung ventilation it does raise the possibility that it may be possible to identify the minority of patients who respond to NO. Continue Reading »