Introduction: Forced expiratory value in one score (FEV1) / Forced vitalcapacity (FVC) was used in classical literature for primary classifications ofpulmonary disorders. American Thoracic Society/ European RespiratorySociety guidelines recommended using FEV1/VC instead of FEV1/FVC. Theaim of study was determination of the extent of superiority of FEV1/VCover the FEV1/FVC.Materials and Methods: Two hundred seven subjects whom sufferedfrom different pulmonary disorders were evaluated by standardspirometry, lung volume and Carbon mono-oxide lung diffusion capacity(DLCO). Accuracy of FEV1/VC and FEV1/FVC for diagnosing lung diseasewas compared by area under the ROC curve, sensitivity and specificityanalysis including Kraemer efficiency and likelihood ration methods. Goldstandards were diagnosis confirmed by over-all clinical and para-clinicaljudgment.Results: Primary classification of FEV1/FVC and FEV1/VC according togold standards showed that FEV1/FVC detected obstructive and restrictivelung disease better than FEV1/VC. FEV1/FVC was able to detect the obstructive and restrictive lung disease correctly in 61% and 34% andFEV1/VC in 56% and 33% respectively. FEV1/FVC showed 100%agreement with forced expiratory flow (FEF)=25-75%, and Maximumexpiratory flow (MEF)=50% but this agreement for FEV1/VC was 95-96%.Accuracy assessments revealed the superiority of FEV/FVC in thelikelihood ratio method. Also, based on the ROC curve and Kraemer’scoefficient, more accurate results were obtained by FEV1/FVC, comparedto FEV1/VC.Conclusion: FEV1/FVC showed marginally higher accuracy for detectinglung disease than FEV1/VC.

Background: In Iran, 25 000 open heart surgeries are performed annually, which are mainly dedicated to coronary artery bypass surgery. Pulmonary complications after open heart surgery impose a high socio-economic burden on the society because of the length of hospital stay and the use of mechanical means. In this study, we aimed to investigate the possibility of impaired forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FVC/FEV1 indices before and after open heart surgery, which has been directly addressed in fewer studies. Methods: In this cross-sectional study, all 125 candidates for open heart surgery who referred to Shahid Mohammadi Hospital of Bandar Abbas University of Medical Sciences during 2107-2018 were included. The patients were evaluated by spirometry three times. Before the operation, FEV1, FVC, FEV1/FVC were measured 3-10 days and 3-6 months after surgery. Then, the changes obtained from the evaluation were extracted three times before surgery, and 3-10 days and 3-6 months after surgery, using IBM SPSS, version 17, descriptive statistics (mean, standard deviation, percentage, etc. ), and one-way and repeated measures analysis of variance. Results: FVC decreased by 0. 6 in both patients with asthma and healthy ones. The mean FVC was also 0. 4 in the diabetic group and 0. 7 in the non-diabetic group. Mean FEV1 before surgery A, one week after surgery B and three to six months after surgery C in the two asthma and healthy groups showed a decrease of 1. 2 and 1. 3, respectively. Mean FEV1 before surgery A, one week after surgery B and three to six months after surgery C in smokers and non-smokers decreased by 0. 9 and 1, respectively. Conclusion: Based on the results of our study, there is no doubt about the development of pulmonary dysfunction after heart surgery. This disorder occurred in the present study independent from asthma, diabetes, and smoking.

Background: Malnutrition is an effective factor in respiratory muscles dysfunction in patients with chronic obstructive pulmonary disease (COPD). The present study was performed to evaluate the effect of improved nutrition on inspiratory muscles in patients with advanced COPD. Materials and Methods: Total of 33 patients suffering from emphysema were studied during a 3-year period using a quasi experimental (before- after study) method. All of them had forced expiratory volume in one second (FEV1) <30% and had received Atrovent, Salmeterol, Becotide (in maximum doses) and oxygen therapy for at least one year. Initially, FEV1 and airways resistance of patients were measured using body plethysmography. After a 35 Kcal/kg diet including 20-40% fat, 40% protein and 20% carbohydrates, these patients were followed by monthly scheduled visits. Spirometric parameters were measured again 3 and 6 months later and the results were analyzed using Freedman method. Results: Pulmonary function tests of the under study patients at the beginning, 3 and 6 months later were as follows respectively; FEV1; 18.3%, 19.57%, 20.95%, airways resistance; 65.3%, 63.7%, 64.9% and maximal inspiratory pressure (MIP); 2.59, 3.062 and 3.29 cmH2O. There was a significant difference in FEV1 and MIP of patients in 3 and 6 months period (P<0.05). Meanwhile, there was no significant difference in airways resistance of patients (P=0.08). Conclusion: Improved nutrition results in increased MIP and FEV1 without changing in other indices (i.e. constant airways resistance indicates constant treatment status of the patient). Thus, an appropriate nutritional diet including sufficient calorie with small frequent meals at least for six months can increase FEV1 by reinforcing inspiratory muscles resulting in improved pulmonary function.    

Background and objective: Because of fixed airway obstruction in patients with laryngeal tumors, measurement of FEV1 can help in predicting the degree of airway obstruction and deciding the safe plan for anesthesia.Materials and methods: 154 patients, 40-80 years old, with ASA class II-III who were scheduled for elective surgery enrolled in this study. Pulmonary function tests (PFT) was done before surgery for all patients. They were divided into three groups based on the result of PFT: Group 1: FEV1> 2.5 L which received standard anesthesia induction. Group 2: FEV1=1.5-2.5 L, induction was performed by keeping spontaneous breathing and Group 3: FEV1 < 1.5 L: which awake intubation was performed with topical anesthesia.Results:  there was significant difference in intubation time and attempts among 3 groups (8.91.8, 10.7±1.7, 15.6±6.3 sec.p=.000; 1.2±0.5, 1.4±0.6, 1.7±0.8, p=.002 respectively). Failed intubations were 3, 4, 9 in three groups respectively, which was not statistically different (P=0.1). Conclusion: Due to fixed airway obstruction in patients with laryngeal tumors, FEV1 can be used as a predictor for classification and choosing a safe method for induction of anesthesia.

Background: Chronic obstructive pulmonary diseases (COPD) have been defined by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) as irreversible conditions which are diagnosed by fixed cut-off points of FEV1/FVC.Objective: The aim of this study was to determine the cut-off points for FEV1/FEV6 ratio and FEV6 as alternatives for FEV1/FVC and FVC in detection of airway obstruction and lung restriction, respectively.Materials and Methods: A total of 318 Spiro metric examinations of subjects referred to Shariati hospital were analyzed. A subject was considered to have obstruction if FEV1/FVC was lower than 70%. The restriction was defined as FVC dlt; 80% in the absence of obstruction. The Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FEV1/FEV6 and FEV6 were calculated.Results: This study shows that the current cut-off points used to detect obstruction and restriction can be replaced by FEV1/FEV6 dlt; 71% and FEV6 dlt; 83%, respectively. FEV1/FEV6 had sensitivity of 95.5% and specificity of 99.4%; the PPV and NPVs were 99.3% and 96.3%. The prevalence of obstruction was 49.4%. For restrictive pattern, FEV6 had sensitivity of 93%, specificity of 79.5% with PPV of 18% and NPV of 99.5%. The prevalence of restriction was 6.3%.Conclusions: The FEV1/FEV6 ratio can be used as a valid surrogate for FEV1/FVC in the diagnosis of airway obstruction, especially for screening purposes in high-risk populations for COPD. Moreover, FEV6 is an acceptable alternative for FVC in detection of restrictive pattern.