Pulmonary Edema and Pleural Effusion Detection Using Efficient Net-V1-B4 Architecture and AdamW Optimizer from Chest X-Rays Images

This paper presents a novelmulticlass systemdesigned to detect pleural effusion and pulmonary edema on chest Xray images,addressing the critical need for early detection in healthcare.A new comprehensive dataset was formed by combining 28,309 samples from the ChestX-ray14,PadChest,and CheXpert databases,with 10,287,6022,and 12,000 samples representing Pleural Effusion,Pulmonary Edema,and Normal cases,respectively.Consequently,the preprocessing step involves applying the Contrast Limited Adaptive Histogram Equalization(CLAHE)method to boost the local contrast of the X-ray samples,then resizing the images to 380×380 dimensions,followed by using the data augmentation technique.The classification task employs a deep learning model based on the EfficientNet-V1-B4 architecture and is trained using the AdamW optimizer.The proposed multiclass system achieved an accuracy(ACC)of 98.3%,recall of 98.3%,precision of 98.7%,and F1-score of 98.7%.Moreover,the robustness of the model was revealed by the Receiver Operating Characteristic(ROC)analysis,which demonstrated an Area Under the Curve(AUC)of 1.00 for edema and normal cases and 0.99 for effusion.The experimental results demonstrate the superiority of the proposedmulti-class system,which has the potential to assist clinicians in timely and accurate diagnosis,leading to improved patient outcomes.Notably,ablation-CAM visualization at the last convolutional layer portrayed further enhanced diagnostic capabilities with heat maps on X-ray images,which will aid clinicians in interpreting and localizing abnormalities more effectively.

Comparison of efficacy of lung ultrasound and chest X-ray in diagnosing pulmonary edema and pleural effusion in ICU patients: A single centre, prospective, observational study

Background and Aims While chest X-ray (CXR) has been a conventional tool in intensive care units (ICUs) to identify lung pathologies, computed tomography (CT) scan remains the gold standard. Use of lung ultrasound (LUS) in resource-rich ICUs is still under investigation. The present study compares the utility of LUS to that of CXR in identifying pulmonary edema and pleural effusion in ICU patients. In addition, consolidation and pneumothorax were analyzed as secondary outcome measures. Material and Methods This is a prospective, single centric, observational study. Patients admitted in ICU were examined for lung pathologies, using LUS by a trained intensivist;and CXR done within 4 hours of each other. The final diagnosis was ascertained by an independent senior radiologist, based on the complete medical chart including clinical findings and the results of thoracic CT, if available. The results were compared and analyzed. Results Sensitivity, specificity and diagnostic accuracy of LUS was 95%, 94.4%, 94.67% for pleural effusion;and 98.33%, 97.78%, 98.00% for pulmonary edema respectively. Corresponding values with CXR were 48.33%, 76.67%, 65.33% for pleural effusion;and 36.67%, 82.22% and 64.00% for pulmonary edema respectively. Sensitivity, specificity and diagnostic accuracy of LUS was 91.30%, 96.85%, 96.00% for consolidation;and 100.00%, 79.02%, 80.00% for pneumothorax respectively. Corresponding values with CXR were 60.87%, 81.10%, 78.00% for consolidation;and 71.3%, 97.20%, 96.00% for pneumothorax respectively. Conclusion LUS has better diagnostic accuracy in diagnosis of pleural effusion and pulmonary edema when compared with CXR and is thus recommended as an effective alternative for diagnosis of these conditions in acute care settings. Our study recommends that a thoracic CT scan can be avoided in most of such cases.

Emergency Hybrid Correction in a Newborn with Critical Aortic Valve Stenosis with Acute Pulmonary Edema in the First Hour after Birth

Critical aortic valve stenosis in newborns is the cause of a severe clinical condition with the onset of symptoms during first hours after birth.We present a clinical case of a successful surgical correction of a critical aortic stenosis using a hybrid method applied in a newborn during the first day of life.The infant was diagnosed with a hypoplastic left heart complex with an intact atrial septum(aortic and mitral valves stenosis variant),that led to the cardiogenic shock and acute pulmonary edema.The procedure included bilateral banding of the pulmonary artery branches and atrioseptostomy with stenting of the interatrial septum.The surgery was performed through a median sternotomy.

Endothelial Nitric Oxide Synthase Gene Polymorphisms Associated with Susceptibility to High Altitude Pulmonary Edema in Chinese Railway Construction Workers at Qinghai-Tibet over 4500 Meters above Sea Level

Objective To examine whether the polymorphisms of endothelial nitric oxide synthase (eNOS) gene are associated with the susceptibility to high altitude pulmonary edema (HAPE) in Chinese railway construction workers at Qinghai-Tibet where the altitude is over 4 500 m above sea level. Methods A case-control study was conducted including 149 HAPE patients in the construction workers and 160 healthy controls randomly recruited from their co-workers, matching the patients in ethnicity, age, sex, lifestyle, and working conditions. Three polymorphisms of eNOS gene, T-786C in promoter, 894G/T in exon 7, and 27bp variable number tandem repeat (VNTR) in intron 4, were genotyped using polymerase chain reaction (PCR) and confirmed with DNA sequencing. Results The frequencies of 894T allele and heterozygous G/T of the 894G/T variant were significantly higher in HAPE patients group than in the control group (P=0.0028 and P=0.0047, respectively). However, the frequencies of the T-786C in promoter and the 27bp VNTR in intron 4 were not significantly different between the two groups. Haplotypic analysis revealed that the frequencies of two haplotypes (H3,T-T-b, b indicates 5 repeats of 27 bp VNTR; H6, C-G-a, a indicates 4 repeats of 27 bp VNTR) were significantly higher in HAPE patients (both P<0.0001). On the contrary, the frequencies of H1 (T-G-b) and H2 (T-G-a) were lower in HAPE patients than in healthy controls (both P<0.001). Conclusions Two haplotypes (T-T-b and C-G-a) may be strongly associated with susceptibility to HAPE. Compared with the individual alleles of eNOS gene, the interaction of multiple genetic markers within a haplotype may be a major determinant for the susceptibility to HAPE.

Clinical characteristics and treatment of severe encephalitis associated with neurogenic pulmonary edema caused by enterovirus 71 in China

BACKGROUND： Hand-foot-mouth disease has become a major public health issue in children in China. In the present prospective study we investigated the clinical characteristics and emergency management of children with severe encephalitis associated with NPE caused by enterovirus 71.METHODS： The study was conducted in 2 pediatric intensive care units （PICUs） over a 2-month period. Clinical records were reviewed of critically ill children with severe encephalitis associated with NPE caused by EV71 who were admitted to PICUs during the period of May to June 2008 in Fuyang.RESULTS： We reviewed the complete records of 36 children, of whom 23 （63.9%） were male and 13 （36.1%） female. Their age ranged from 4 to 48 months, with an average of 15.8 months. All children except one were under 3 years of age. The overall mortality in these children was 19.4%. The average duration of critical life threatening signs and symptoms was 2.1 days （12 hours-5 days）. Nervous system diseases included brainstem encephalitis in 27 children （75%）, brainstem encephalitis associated with myelitis in 6 children （16.7%）, and general encephalitis in 3 chidren （8.3%）, respectively. In 12 patients of NPE （33.3%） pink or bloody bubble sputum and asymmetric pulmonary edema or hemorrhage was the primary manifestation but no typical exanthema was observed. Five children died of acute onset of NPE and / or pulmonary hemorrhage with rapid progression of cardiopulmonary failure within hours after admission. Therapeutic management consisted of mechanical ventilation and administration of mannitol, methylprednisolone, intravenous immunoglobulin （IVIG） and vasoactive drugs, associated with the need of fluid volume resuscitation in 9 （25%） of the 36 children.CONCLUSION： In children less than 3 years of age found to be affected by severe EV71 encephalitis associated with NPE, one fifth may die. The major organ systems infected by severe EV71 include the central nervous system, the respiratory system, and the cardiovascular system. Early diagnosis and evaluation, respiratory support, treatment of intracranial hypertension, and mainttenance of function of the cardiovascular system are the most important therapeutic measures.

Non-cardiogenic acute pulmonary edema in elderly patient with Dressier syndrome associated pulmonary embolism

Pulmonary embolism （PE） is a common cardiovascular and cardiopulmonary illness and the incidence increases exponentially with age. Because the clinical signs and symptoms are non-specific, its diagnosis is always difficult.

Studies on monitoring hemodynamics and oxygen dynamics of adult respiratory distress syndrome secondary to high altitude pulmonary edema

To study monitoring hemodynamics and oxygen dynamics of adult respiratory distress syndrome (ARDS) secondary to high altitude pulmonary edema (HAPE),we performed clinic and laboratory studies in 8 patients who preliminarily developed high altitude cerebral edema (HACE) and then ARDS occurred at an altitude of 4 500 m. After an initial emergency treatment on high mountains,all the patients were rapidly transported to a hospital at a lower altitude of 2 808 m. The right cardiac catheterizations were carried out within 5 h after hospitalized. The monitoring hemodynamics and oxygen dynamics were studied via a thermodilution Swan-Gaze catheter. The results showed that before treatments at the beginning of monitoring,there presented a significant pulmonary artery hypertension with a decreased cardiac function,and a lower oxygen metabolism in all the 8 patients. However,after some effective treatments,including mechanical ventilation and using dexamethasone,furosemide,etc,four days later the result of a repeated monitoring showed that their pulmonary artery pressure had been decreased with an improved cardiac function with all the oxygen metabolic indexes increased significantly. Our studies suggested that performing monitoring hemodynamics in patients with ARDS secondary to HAPE will define the clinical therapeutic measures which will benefit the outcome.

Subclinical high altitude pulmonary edema: A clinical observation of 12 cases in Yushu

During the Yushu Earthquake on April 14,2010,a high incidence of acute high altitude illness was observed in the mountain rescuers,and 0.73 % of these patients suffered from high altitude pulmonary edema,of which 12 patients developed subclinical pulmonary edema and concomitantly contracted acute mountain sickness. Symptoms and signs were atypically high heart rate with high respiratory rate,striking cyanosis,and significantly low oxygen saturation,whereas no moist rates were heard on auscultation,and Chest X-ray showed peripheral with a patchy distribution of mottled infiltrations in one or both lung fields. We believe that subclinical high altitude pulmonary edema is an earliest stage of pulmonary edema at high altitude. The possible pathogenesis and the diagnosis were discussed.

Unilateral pulmonary hemorrhage caused by negative pressure pulmonary edema:A case report

BACKGROUND Unilateral pulmonary hemorrhage is typically reported in young and healthy men with upper respiratory tract obstruction during anesthesia in special situations.Negative pressure in the lungs is created,resulting in negative pressure pulmonary edema(NPPE).CASE SUMMARY A 78-year-old male patient diagnosed with spinal stenosis was admitted to receive a unilateral laminectomy with bilateral decompression.The patient had been diagnosed with hypertension four years earlier and asthma more than 70 years earlier.We experienced a unilateral alveolar hemorrhage associated with NPPE that occurred in a longstanding asthma patient who bit the intubated endotracheal tube for a short period during posture change at the end of surgery.Because diffuse alveolar hemorrhage accompanied by NPPE was caused in this case by airway obstruction in an older patient with asthma without known risk factors,anesthesiologists should be careful not to induce airway irritation during anesthesia awakening in asthma patients.CONCLUSION Because diffuse alveolar hemorrhage accompanied by NPPE can occur,anesthesiologists should take care not to induce airway irritation.

Neural histamine in the tuberomammillary nucleus regulates the onset of neurogenic pulmonary edema in rabbits

Objective： To explore the effect of neural histamine in the tuberomammillary nucleus（TM） on neurogenic pulmonary edema （NPE） onset in rabbits and the function of the rostral ventrolateral medulla（RVLM） in the neural histamine modulation of NPE. Methods： NPE was produced by the intracisternal injections of fibrinogen and thrombin. The contents of histamine in the TM and RVLM in rabbits were measured with high performance liquid chromatography（HPLC）. Rabbits were placed on a stereotaxic frame and microinjection cannulae were inserted into the TM and RVLM using brain atlas coordinates. Animals were pretreated with R- a -methylhistamine（MeHA） in the TM and chlorphenamine Mmaleate/cimetidine in the RVLM prior to establishing the NPE model. Changes in the lung water ratio and mean arterial pressure（MAP） were recorded, and paraffin sections of lung tissue were observed by light microscope. Results：We found that the contents of histamine（HA） in the TM and RVLM increased significantly with the onset of NPE. Pretreatment with MeHA in the TM and chlorphenamine Mmaleate in the RVLM significantly decreased MAP, and the lung water ratio and histological characteristics of the NPE in the rabbit model. Pretreatment with cimetidine in the RVLM had no effect on NPE. Conculsion：The results suggest that neural histamine in the TM is involved in the onset of NPE, and this effect of neural histamine is mediated by H1 receptor in the RVLM

Preoperative Atrial Fibrillation and T-Wave Inversion Associated with Postoperative Pulmonary Edema

Background: Atrial fibrillation (AF) and T wave inversion (TWI) are occasionally found on pre-operative electrocardiograms (EKG) of patients with long standing hy-pertension (HTN) associated with left ventricular hypertrophy (LVH). Each of these two pathologies, AF and LVH, can impose negative hemodynamic effects on the car-diac function. Case: We present a case of a patient with AF, TWI and long standing HTN that went into post-operative pulmonary edema. Conclusion: Even returning to base line poorly controlled hypertension, and even more so during a hypertensive cri-sis, their concurrent presence may inflict even more detrimental effect manifested by elevation of pulmonary venous pressure and pulmonary edema.

Neurogenic Pulmonary Edema after Subarachnoid Hemorrhage

Neurogenic Pulmonary edema(NPE)is a well known complication of severe central nervous system insult,such as subarachnoid hemorrhage(SAH).Endogenous catecholamines can result in NPE.Cardio-respira-tory dysfunction may present severer than the clinical symptom of SAH.ICU management for patients with NPE after SAH is recommended.We describe a patient with NPE after SAH.The rapid development of respiratory and cardiac impairment had masked the initial disease.

Protective effect of extracorporeal membrane pulmonary oxygenation combined with cardiopulmonary resuscitation on post-resuscitation lung injury

BACKGROUND: Cardiac arrest(CA) is a critical condition that is a concern to healthcare workers. Comparative studies on extracorporeal cardiopulmonary resuscitation(ECPR) and conventional cardiopulmonary resuscitation(CCPR) technologies have shown that ECPR is superior to CCPR. However, there is a lack of studies that compare the protective effects of these two resuscitative methods on organs. Therefore, we aim to perform experiments in swine models of ventricular fibrillation-induced CA to study whether the early application of ECPR has advantages over CCPR in the lung injury and to explore the protective mechanism of ECPR on the post-resuscitation pulmonary injury.METHODS: Sixteen male swine were randomized to CCPR(CCPR;n=8;CCPR alone) and ECPR(ECPR;n=8;extracorporeal membrane oxygenation with CCPR) groups, with the restoration of spontaneous circulation at 6 hours as an endpoint. RESULTS: For the two groups, the survival rates between the two groups were not statistically significant(P>0.05), the blood and lung biomarkers were statistically significant(P<0.05), and the extravascular lung water and pulmonary vascular permeability index were statistically significant(P<0.01). Compared with the ECPR group, electron microscopy revealed mostly vacuolated intracellular alveolar type II lamellar bodies and a fuzzy lamellar structure with widening and blurring of the blood-gas barrier in the CCPR group.CONCLUSIONS: ECPR may have pulmonary protective effects, possibly related to the regulation of alveolar surface-active proteins and mitigated oxidative stress response postresuscitation.

THROMBOENDARTERECTOMY FOR CHRONIC PULMONARY THROMBOEMBOLISM

Objective To evaluate the improving reliability and safety of thromboendarterectomy and perioperative management for chronic pulmonary thromboembolism. Methods The clinical data of 12 cases with chronic pulmonary thromboembolism, who underwent thromboendarterec- tomy assisted by low flow or circulation arrest with deep hypothermia, were reviewed retrospectively. Results Pulmonary artery pressure decreased 20 to 40 mmHg immediately after surgical procedures in 9 cases. The postoperative pulmonary edema at various degrees happened in 12 cases, among them, 1 died of severe lung infection and pulmonary re-embolism at 19 days postoperation. Computed tomography pulmonary angiography and angiography of 11 cases indicated that the original obstruction of pulmonary artery disappeared. During the follow-up period of 2 months to 5 years, the clinical symptoms and activity was improved. Conclusion Thromboendarterectomy is an effective treatment for chronic pulmonary thromboembolism. The outcome of the surgical procedure needs to be further investigated and followed up regularly according to an evaluative system, because it might be influenced by multiple factors.

Current status and prospects of basic research and clinical application of mesenchymal stem cells in acute respiratory distress syndrome

Acute respiratory distress syndrome(ARDS)is a common and clinically devastating disease that causes respiratory failure.Morbidity and mortality of patients in intensive care units are stubbornly high,and various complications severely affect the quality of life of survivors.The pathophysiology of ARDS includes increased alveolar–capillary membrane permeability,an influx of protein-rich pulmonary edema fluid,and surfactant dysfunction leading to severe hypoxemia.At present,the main treatment for ARDS is mechanical treatment combined with diuretics to reduce pulmonary edema,which primarily improves symptoms,but the prognosis of patients with ARDS is still very poor.Mesenchymal stem cells(MSCs)are stromal cells that possess the capacity to self-renew and also exhibit multilineage differentiation.MSCs can be isolated from a variety of tissues,such as the umbilical cord,endometrial polyps,menstrual blood,bone marrow,and adipose tissues.Studies have confirmed the critical healing and immunomodulatory properties of MSCs in the treatment of a variety of diseases.Recently,the potential of stem cells in treating ARDS has been explored via basic research and clinical trials.The efficacy of MSCs has been shown in a variety of in vivo models of ARDS,reducing bacterial pneumonia and ischemia-reperfusion injury while promoting the repair of ventilator-induced lung injury.This article reviews the current basic research findings and clinical applications of MSCs in the treatment of ARDS in order to emphasize the clinical prospects of MSCs.

Effectiveness of chest radiography,lung ultrasound and thoracic computed tomography in the diagnosis of congestive heart failure

Hydrostatic pulmonary edema is as an abnormal in-crease in extravascular water secondary to elevatedpressure in the pulmonary circulation, due to conges-tive heart failure or intravascular volume overload.Diagnosis of hydrostatic pulmonary edema is usuallybased on clinical signs associated to conventional ra-diography findings. Interpretation of radiologic signsof cardiogenic pulmonary edema are often question-able and subject. For a bedside prompt evaluation,lung ultrasound(LUS) may assess pulmonary conges-tion through the evaluation of vertical reverberationartifacts, known as B-lines. These artifacts are relatedto multiple minimal acoustic interfaces between smallwater-rich structures and alveolar air, as it happens incase of thickened interlobular septa due to increase of extravascular lung water. The number, diffusion and in-tensity of B lines correlates with both the radiologic andinvasive estimate of extravascular lung water. The inte-gration of conventional chest radiograph with LUS canbe very helpful to obtain the correct diagnosis. Com-puted tomography(CT) is of limited use in the work upof cardiogenic pulmonary edema, due to its high cost,little use in the emergencies and radiation exposure.However, a deep knowledge of CT signs of pulmonaryedema is crucial when other similar pulmonary condi-tions may occasionally be in the differential diagnosis.

Acute lung injury and acute respiratory distress syndrome： experimental and clinical investigations

Acute lung injury （ALl） or acute respiratory distress syndrome （ARDS） can be associated with various disorders. Recent investigation has involved clinical studies in collaboration with clinical investigators and pathologists on the pathogenetic mechanisms of ALl or ARDS caused by various disorders. This literature review includes a brief historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the long-term experimental studies and clinical investigations from our laboratory, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.

Acute cerebral and pulmonary edema induced by hemodialysis in a dog model

Background The dialysis disequilibrium syndrome which occurs after hemodialysis. The purpose of this pulmonary edema induced by hemodialysis. s characterized by neurologic deterioration and cerebral edema study was to investigate the pathogenesis of acute cerebral and pulmonary edema induced by nemodialysis.Methods We evaluated the effects of hemodialysis on the biochemical and hemodynamic parameters of the plasma and cerebrospinal fluid, including the intracranial pressure, dry/wet ratio, and pulmonary edema index, and we also examined the pathological changes of the brain and lung tissue in dogs suffering from uremia. Results Seventy-two hours after bilateral ureteral ligation, 10 uremic dogs were hemodialyzed for 2 hours, yielding a 73.6% and 60.1% decrease in the plasma urea and creatinine, respectively, a decrease in the plasma osmolality from （359±18） mOsm/kgH2O to （304±6） mOsm/kgH2O （P 〈0.01）, a decrease in the dry/wet ratio of the lung and brain tissue, and an increase in the hemodynamic parameters （right atrial pressure, right ventricular pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, and central venous pressure）, intracranial pressure, total pulmonary resistance index, and pulmonary edema index. Moreover, the pathological examination revealed lung and brain edema in the dialyzed dogs. This group was compared to 3 control groups： 6 uremic dogs which were sham dialyzed without dialysate so that no fall in the plasma urea occurred, and 12 uremic and 12 nonuremic animals that were not dialyzed. However, the parameters mentioned above were not significantly changed among these 3 control groups. Conclusions The acute brain and lung edema in our model appeared to be primarily due to a large osmotic gradient between the plasma and the brain and lung. This is the ＂urea reverse effect＂ which promoted the osmotically-induced lung and brain swelling.

Effect of Phenylephrine on Alveolar Fluid Clearance in Ventilator-induced Lung Injury

Objective To investigate the effect of phenylephrine （an α-adrenergic agonist） on alveolar fluid clearance （AFC） in ventilator-induced lung injury and the possible mechanism involved. Methods A total of 170 male Wistar rats were randomly allocated into 17 groups （n= 10） using ran- dom number tables. Short-term （40 minutes） mechanical ventilation with high tidal volume （HVT） was per- formed to induce lung injury, impair active Na＋ transport and lung liquid clearance in the rats. Unventilated rats served as controls. To demonstrate the effect of phenylephrine on AFC, phenylephrine at different con- centrations （1×10^-5, 1 ×10^-6, 1×10^-7, 1×10^-8, and 1×10^-9 mol/L） was injected into the alveolar space of the HVT ventilated rats. To identify the influence of adrenergic antagonists, Na＋ channel, and microtubular sys- tem on the effect of phenylephrine, phenylephrine at 1×10^-5mol/L combined with prazosin （an α1-adrener- gic antagonist, 1×10^-4 mol/L）, yohimbine （an α2-adrenergic antagonist, 1×10^-4 mol/L）, atenolol （a β1- adrenergic antagonist, 1×10^-5 mol/L）, ICI- 118551 （an β2-adrenergic antagonist, 1×10^-5 mol/L）, amiloride （a Na＋ channel blocker, 51×10^-4mol/L）, ouabain （a Na＋/K＋-ATPase blocker, 5~×10^-4mol/L）, colchicine （a mi- crotubular disrupting agent, 0.25 mg/100 g body weight）, or β-lumicolchicine （an isomer of colchicine, 0.25 mg/100 g body weight） were perfused into the alveolar space of the rats ventilated with HVT for 40 minutes. AFC and total lung water content were measured. Results Basal AFC in control rats was （17.47±2.56）%/hour, which decreased to （9.64± 1.32）%/hour in HVT ventilated rats （P=0.003）. The perfusion of phenylephrine at 1 ×10^-8, 1×10^-7, 1×10^-6, and 1×10^-5 mol/L significantly increased the AFC in HVT ventilated rats （all P〈0.05）. This effect of phenylephrine on AFC was suppressed by prazosin, atenolol, and ICI-118551 in HVT ventilated rats by 53%, 31%, and 37%, respectively （all P〈0.05）. The AFC-stimulating effect of phenylephrine was lowered by 33% and 42% with amiloride and ouabain, respectively （both P〈0.05）. Colchicine significantly inhibited the effect of phenylephrine （P=0.031）. Conclusion Phenylephrine could increase the AFC in HVT-ventilated rats and accelerate the ab- sorption of pulmonary edema.

Protective effect of melatonin on reexpansion pulmonary edema in rats model

Background Rapid reexpansion of collapsed lungs leads to reexpansion pulmonary edema （RPE）. We aimed to investigate the effect of melatonin in the prevention of RPE formation. Methods We used a Wistar rat model in which the left lung was collapsed by ligating the left bronchus for 48 hours and then reexpanded and ventilated for an additional 2 hours. Thirty minutes before reexpansion, we injected melatonin （10 mg/kg） or vehicle intraperitoneally. We compared the wet/dry ratio, oxygenation index, myeloperoxidase （MPO） activity, nitric oxide （NO）, malondialdehyde （MDA） and interleukin 8 （IL-8） levels in the reexpanded lungs between untreated and treated animals. Results We found that the wet/dry ratio of the melatonin group was significantly lower than that of the vehicle group, and the oxygenation index was higher in the melatonin group. Compared with the control, melatonin pretreatment significantly decreased the activities of IL-8, NO, MDA levels and MPO in lung tissues. Histopathology of reexpanded lungs showed that the melatonin pretreatment group had less pulmonary edema and less inflammatory cell infiltration. Conclusion Melatonin decreases pulmonary edema and improves oxygenation after reexpansion by attenuating oxidative stress and inhibiting pro-inflammatory cytokines.