Open Access Research Article Anesthesia & Clinical Research Machado et al., J Anesth Clin Res 2014, 5:8 http://dx.doi.org/10.4172/2155-6148.1000428 Volume 5 • Issue 8 • 1000428 J Anesth Clin Res ISSN:2155-6148 JACR an open access journal Keywords: Infammatory response; One-lung ventilation; Atelectasis Introduction Pulmonary complications such as infection and acute lung injury (ALI) may lead to high morbidity rates afer thoracic surgery and/or one-lung ventilation (OLV) [1,2]. Infammation afer lung surgery is pointed out as an important cause for the development of ALI [3,4]. Te incidence of ALI varies from 2, 5% in patients submitted to thoracic surgery in general to 7, 9% of patients submitted to pneumonectomy [5]. During thoracic surgery several factors can lead to the release of pro-infammatory mediators (with the subsequent activation of neutrophils that alter endovascular permeability), namely overdistension, hypoxia, hyperoxia and possibly isquemia-reperfusion injury [6]. Also, mechanical ventilation by itself may induce several alveolar changes which are not seen during spontaneous ventilation [6]. In addition, surgical manipulation of the lung may aggravate the alveolar injury with leukocyte recruitment in both lungs during OLV [6]. Tese fndings support the multiple hit hypotheses, in which lung damage during thoracic surgery may be due to: mechanical ventilation, OLV, surgical manipulation, lung overdistension, atelectrauma and re- expansion/reperfusion injury [7]. However, as far as we know, there are no reported studies that show an independent efect of OLV on lung infammatory response. Tus, in an experimental controlled animal model with spontaneous ventilation, we hypothesized that lung infammatory response is not increased by one-lung ventilation itself. Materials and Methods Animals Te experimental protocol used in this study was approved by the ethics committee, and carried out according to the European Union Directive nº 63/2010/EU. Twenty adult New Zealand rabbits were purchased from a Portuguese breeder (NORLAP-Rui M.S. Gonçalo, 4825-466 Água-Longa, Portugal) and kept under standard housing conditions with unrestricted access to food and water, with attendance by veterinary doctors and daily inspection. Study inclusion criteria for rabbits were based on general well being status, namely normal food and water ingestion, with absence of self-mutilation and weigh loss. *Corresponding author: Humberto S Machado, Department, Centro Hospitalar do Porto, Largo Abel Salazar, 4099-001 Porto, Portugal, Tel: 351 935848475; Fax: 351 220900644; E-mail: hjs.machado@gmail.com Received May 28, 2014; Accepted August 05, 2014; Published August 10, 2014 Citation: Machado HS, Sá P, Nunes CS, Couceiro A, da Silva ÁM, et al. (2014) Spontaneous One-Lung Ventilation Increases the Lung Infammatory Response: An Experimental Pilot Study. J Anesth Clin Res 5: 428. doi:10.4172/2155- 6148.1000428 Copyright: © 2014 Machado HS, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Spontaneous One-Lung Ventilation Increases the Lung Inflammatory Response: An Experimental Pilot Study Humberto S Machado 1 *, Paula Sá 1 , Catarina S Nunes 2 , António Couceiro 3 , Álvaro Moreira da Silva 4 and Artur Águas 5 1 Anesthesiology Department, Centro Hospitalar do Porto, Largo Abel Salazar, 4099-001 Porto, Portugal 2 Open University, Department of Science and Technology and Anesthesiology Department, Centro Hospitalar do Porto, Largo Abel Salazar, 4099-001 Porto, Portugal 3 Pathological Anatomy service, Gaia/Espinho Hospital Centre, Rua Conceição Fernandes, 4430 Vila Nova de Gaia, Portugal 4 Intensive care Service, Port Hospital Center, Largo Abel Salazar, 4099-001 Porto, Portugal 5 Department of Normal Anatomy, Abel Salazar Biomedical Sciences Institute-University of Porto and Multidisciplinary Biomedical Research Unit, St. Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal Abstract Study objective: The purpose of this study was to investigate if spontaneous one-lung ventilation would induce any type of infammatory lung response when compared to spontaneous two-lung ventilation and its intensity, by quantifcation of infammatory cells in lung histology at the end of the procedure. Design: In vivo prospective randomised animal study Setting: University research laboratory Subjects: New Zealand rabbits Interventions: Rabbits (n=20) were randomly assigned to 4 groups (n=5 each group). Groups 1 and 2 were submitted to one-lung ventilation, during 20 and 75 minutes respectively; groups 3 and 4 were submitted to two-lung ventilation during 20 and 75 minutes and considered controls. Ketamine/xylazine was administered for induction and maintenance of anesthesia. One-lung ventilation was achieved by administration of air into the interpleural space, and left lung collapse was visually confrmed through the centre of the diaphragm. Measurements: Lung histology preparations were observed under light microscopy for quantifcation of the infammatory response (light, moderate and severe). Main results: All subjects had at least light infammatory response. However, rabbits submitted to one-lung ventilation had a statistically signifcant value for the occurrence of moderate infammation (p<0.05). The infammatory response found included mainly eosinophils, with an average proportion of 75/25 to other polymorphonuclear cells. No differences between groups were found regarding gas exchange, heart rate and respiratory rate. Conclusions: In this spontaneous one-lung ventilation model, lung collapse was positively associated with a greater infammatory response when compared to normal two-lung ventilation.