جستجوی مقالات مرتبط با کلیدواژه « تهویه » در نشریات گروه « پزشکی »

Studies have demonstrated that teaching carries a substantial burden of health risks. Prevalent health issues among teachers include asthma, respiratory diseases, musculoskeletal problems, and mental disorders. These problems can be attributed to the specific attributes of their work environment. Consequently, this study aims to investigate the correlation between air quality within educational establishments and the overall health of teachers.

This systematic review aims to examine the impact of temperature, humidity, and ventilation rates within educational environments on teachers’ health status and thermal comfort. Relevant studies were searched for using the PubMed and Web of Science databases, employing keywords such as teacher, temperature, humidity, ventilation, school, classroom, health symptoms, and thermal comfort (2000-2022). The inclusion criterion was that articles examined teachers’ health and comfort with temperature, relative humidity, and ventilation of the educational place.

Out of the 103 articles found in the initial search, 13 articles were finally reviewed. Six studies investigated the voice abnormalities of teachers due to various factors (including temperature, relative humidity, and the ventilation rate of the educational place) and found that these abnormalities were affected by these factors. Two studies explored the relationship between the prevalence and exacerbation of respiratory symptoms and quality parameters of the indoor environment of educational places. Additionally, five studies investigated the relationship of air quality parameters of educational places with common non-specific symptoms among teachers.

Teachers frequently experience symptoms such as voice disorders, respiratory difficulties, allergies, and other nonspecific ailments, which may be associated with the quality parameters of the indoor environment in educational settings. These parameters include temperature, humidity, and ventilation rate. Consequently, controlling and regulating these parameters within the recommended values can help prevent the onset or exacerbation of these symptoms.

Oxygen therapy is one of the important topics of supportive treatment in COVID-19 patients. The present study aims of determining the effect of targeted oxygen therapy on the recovery outcomes of patients with COVID-19 in a selected military hospital in Tehran in 1400.

A single-blind clinical trial with a control and intervention group was performed on COVID-19 patients admitted to Baqiyatallah Al-Azam Hospital from October 26 to November 20, 2021. The sampling method was simply random and the sample size of 40 people in both groups was calculated. Data collection (improvement outcomes) using demographic information registration form and checklist of clinical findings (shortness of breath, respiratory retention test, six-minute walk test, laboratory tests (Troponin, CDK, LDH), chest pain, in The period at arrival was 24 hours after admission and discharge time. Data using SPSS software version 25, descriptive statistics (mean, standard deviation, and frequency), and inferential statistics (Chi-square test, paired t-test, Friedman) in 95% confidence level were analyzed.

The results of the present study showed a significant difference between the consequences of shortness of breath, systolic blood pressure, chest pain, and a six-minute walk test (P<0.05). Also, there was no significant difference in serum LDH and CPK levels between the intervention and control groups at the time of admission. But there was a significant difference in serum Tropinin level (P<0.05).

Targeted oxygen therapy has been effective as a supportive strategy to improve oxygen delivery in COVID-19 patients and reduce the consequences of this disease. Given the current need for additional supportive therapy to improve oxygen delivery, targeted oxygen therapy is recommended as a new medical supportive treatment in COVID-19 patients.

Methane is one of the most widely used gases in industries with a high flammability potential. This study aimed to evaluate the efficiency of ventilation systems installed on methane valve pits based on hazardous areas classification.

This study was implemented in a steel industry in Qom Province in 2019. The tools used in this study were a DELTA OHM pitot tube (DO-2003) to measure wind speed, EPA Protocol for equipment leak emission estimates (U.S. Environmental Protection Agency) and IEC-60079-10 for evaluating the safety of ventilation of methane valve pits.

The methane LELm was about 0.0334 kg/m3, and the volume of the release area was approximately VZ = 0.053 m3. The expected leak emissions were within the Vz < 0.1 m3 range. The ventilation system embedded on methane distribution pipelines was not effective for openings with diameters of more than 0.3 mm and the volume of gas inside the valve pits would quickly exceed high ventilation border which might lead to a dangerous accumulation of gas in the valve pits.

Given that a very small opening or leak in gas transmission valves may lead to the formation of an explosive atmosphere, it is essential to monitor methane before entering the valve pit area and performing any operations on valve pits.

The use or non-use of non-invasive mechanical ventilation (NIV) is one of the most important concerns of the treatment team in acute respiratory distress caused by Covid 19 disease. Therefore, this review study was conducted to determine the use or non-use of this ventilation in respiratory distress caused by the Covid 19 pandemic. This systematic study was conducted in 2021 with the entry of 14 articles. For this purpose, the articles were reviewed by the authors with the help of article quality index. In response to 4 questions posed to the authors regarding non-invasive mechanical ventilation in Covid 19 patients, it was found that although this ventilation is widely used in Covid 19 patients, in any case, there is a need for further studies and clinical guidelines in This is especially mandatory.

Considering the importance of anesthesia in people who are very obese, and the need to take the necessary activities to minimize the complications during and after the operation in these patients, this study aimed to compare ventilation quality by anatomic or nasal mask after induction of general anesthesia in patients with body mass index (BMI) of above 40 kg/m2.

In this randomized clinical trial study, 70 obese patients with a BMI of more than 40 kg/m2 who were candidates for surgery were selected and randomly divided into two groups of 35. The first group were ventilated with oral mask and 100% oxygen for three minutes, and in the second group, ventilation was performed through the nasal mask. The hemodynamic and ventilation parameters and complications during and after surgery were evaluated and compared between the two groups.

Evaluation of hemodynamic parameters during and after surgery did not show any clinical difference between the two groups. However, nasal ventilation patients had better ventilation and oxygenation indexes.

The results of our study showed that the use of nasal mask instead of oral mask have a more favorable ventilation end-tidal CO2 (ETCO2) and oxygenation (SpO2) in patients undergoing surgery, and the same hemodynamic stability after induction of anesthesia in very obese patients.

Increasing the concentration of carbon dioxide (CO2) leads to reduced comfort and learning disruption. Therefore, the present study was conducted to determine the concentration of CO2 in classrooms of Babol and Gonabad cities and its relationship with classroom ventilation and temperature. This descriptive study was randomly carried out in spring of 2018 in 6 high schools and 28 classrooms of Babol in the north of Iran and 28 educational classes in Gonabad University of Medical Sciences in the east of Iran. A CO2 meter was used to measure CO2. In order to determine the physical parameters affecting CO2 concentration, information of a checklist was used. Data were analyzed by statistical tests such as Chi-square, ANOVA and t-test. In the present study, there was a significant correlation between CO2 and ventilation type (p = 0.021) and heating system in Babol schools (p = 0.025). There was a significant relationship between CO2 concentration in school and university classes (p=0.001) in Babol and Gonabad. The present study showed that CO2 concentration was high in most classes and it was related to the type of ventilation and heating and cooling systems

The ultimate purpose of respiration is to maintain adequate densities of O2, CO2, and H in the tissues. Respiratory activities are very sensitive to each of these substances. The present study aims to examine effect of eight weeks of power yoga exercises on respiratory efficiency of young healthy women. Therefore, 22 women with average age of 22.71±0.9 years, average height of 165±8.93 centimeters, and body mass index of 23.80±2.18 participated voluntarily in two divided groups of exercise and control, in this study. The applied exercise program of this study included 8 weeks of yoga exercises (Asana), performed during 3 sessions of 90 minutes in a week. The spirometer gas analyzer device was used to measure respiratory gases. The subjects continued modified Bruce protocol up to test distress. Measurements were repeated again after eight weeks and 48 hours after the last exercise session. The results showed that eight weeks of power yoga exercises lead to significant differences in VO2max, RER, VT, VE, EQO2, EQCO2, and PETO2 factors between two groups. But no significant differences observed in PETCO2 and VE/VCO2 factors between two groups. It seems that observing no significant differences in VE/VCO2 factor is due to low initial rate of VE/VCO2 gradient. But differences in respiratory models and the type of used protocol (progressive intermediate) could be effective.

One of the most important factors impacting the performance and efficiency of production is ventilation that plays this crucial role with reduction the pollution and heat. The purpose of the present article is to determine the impacts of improving the ventilation systems on performance and efficiency of production through controlling the physical parameters such as temperature and moisture and also with controlling the chemical factors of workplace in Autoconer unit of a spinning company.
Research data have been assessed using dry thermometer, wet thermometer and digital humidity thermometer measuring environmental parameters. These parameters have been used to evaluate the thermal discomfort indicators (DI). The sampling was performed using NIOSH-0600 protocol by aluminum cyclone and 25 mm PVC filter. Using Gravimetric analysis method through a scale with an accuracy of 0.0001 gr data related to concentration of the polyester and cotton pollutant dusts, respirable dust, have been assessed. Obtained data from measuring the concentration of pollutants have been used to estimate the effectiveness of ventilation systems. The amount of the production has been assessed by multiplying of measuring the reel samples and number of reels or spring-enabled device to ascertain the efficiency of production. All of the investigations and comparisons have been conducted in three conditional situations including without suitable ventilation system, improved and adjusted ventilation system and finally designing and installing the new ventilation system; in the all of the stations of Autoconor unit.
Results of the study indicated that the amounts of DI in three investigated saloons didn’t have significant differences and all of them were close to thermal comfort (P=0.45); and despite of exert small changes, it has not been observed significant differences between thermal discomfort indicator (DI) with process of improving air conditioning (P=0.42). On the other hand, it has been determined that improving the ventilation system by reduction the pollutants, increased the production and efficiency of the work (P 0.05).
The present study shows that improving ventilation system through controlling the chemical parameters and physical parameters, with lower impacts; including temperature and moisture will have an important role in increasing the operation and efficiency of production in spinning industry.

Designing of a ventilation system is a complex process. In addition to the time consuming calculations of each branch, it requires iterative calculations for balancing parallel branches. Designing of a proper hood, selecting of appropriate duct diameters and choosing of suitable fan are designing processes in which the error may enforce to decrease the system performance and impose additional costs to the system. Error is likely in manual calculations. In present study, a software tool was developed and validated for local exhaust ventilation system design and calculations. The program was written in Visual Basic. Validation of the software was carried out in two parts. The perfection of the provided codes was studied first. In the second part of the validation process, computational results were studied. For this purpose, the validation was conducted in three steps. The results of each part of the program were compared with the results of manual calculations for simple example, benchmark data, and the results obtained from a credited software program. The Bland-Altman analytical method was applied to statistically compare the overall results. The results revealed that in single hood ventilation systems where the ducts are connected in series, the maximum difference between similar results of the program and benchmark data was 1.27% and the least difference was 0 percent. In complex systems with more than one hood and parallel ducts, the maximum disparity between two similar results gained from this program and either benchmark data or a credited program was 1.77% while the minimum disparity was 0%. Bland-Altman analyses showed that standard deviation of the results from the application of this program to 38-duct pieces was in the range of ± 0.01% for velocity pressure, static pressure as well as total pressure. The present software is a reliable tool for local exhaust ventilation design.

Toluene effects on the nervous system and causes numbness, lack of control in voluntary muscles and seizures. Ethyl benzene can also cause irritation of the eyes and throat and at higher concentrations it can damage the nervous system. Exposure with toluene and ethyl benzene may occur in different environments such as vehicle cabindue to possible emissions of vehicle interior decoration. The aim of this study was to estimate the concentrations of toluene and ethyl benzene with the internal source in the cabin of Logan (L90) cars. In this study, 44 vehicles were sampled. Samples were collected using personal sampling pumps and sorbent activated carbon. The samples were analyzed using gas chromatography equipped with mass detecto r. A check list was used to collect the other required information. The mean concentrations of toluene and ethyl benzene in vehicles were respectively 42.2 and 17.44 µg/m3. Toluene and ethyl benzene concentrations were significantly higher in the new cars. T he natural ventilation significantly reduced the concentrations of toluene and e thyl benzene inside the cars., However, fuel type and smoking inside the car did not significantly contribute to the concentrations of these two compounds.

Ventilation plays a crucial role in reducing the number of air transmitted pathogens in isolated rooms. Determination of the suitable type of ventilation system and the proper ventilating rate has always been a challenge. Patients’ bed arrangement and the location of the staff are also expected to influence the occupational exposure of the staffs’ to harmful airborne particles. The purpose of this project was to determine the state of ventilation systems, patient’s bed and the location of the healthcare staff in these rooms, upon the risk to the staff being exposed to the airborne pollution in these places. Throughout this practical study, a single-bed hospital room, where a tuberculosis patient had been admitted, was chosen. Thereafter, 5 types of ventilation systems were applied for the experiment. Whilst applying various ventilating scenarios, a patient’s bed and a statue of a hypothetical healthcare staff were positioned in 2 different locations. During each of these experiments, 3 occupational samples were taken from the bio-aerosols in the room. The total density of the bio-aerosols in the patient’s room changes significantly (P<0.001) within different plans. The least amount of capacity and the worst aeration and the concentration of indoor air bio-aerosols meaningfully decreased (p<0.001) in comparison with the air of a room within which no ventilation system is utilized. When air is supplied via a vent on the ceiling and it is exhausted from a vent situated on a wall at the southern part of the room, the total density of the bio-aerosols reduced to 25cfu/m3 (application of 12 air changes per hour). The arrangement of patients’ bed caused 17.75% reduction in total density of the sampled pollutions from the air. Application of a system as determined in this study is recommended for isolated rooms

Surgical smoke contains hazardous chemicals and biological agents. The use of standard surgical masks alone does not provide adequate protection against surgical smokes. Hence, the application of a local exhaust ventilation system to evacuate surgical smokes is recommended. To design, construct, and evaluate a portable local exhaust ventilation system to control electrosurgery smokes. This was an experimental study carried out at Qazvin University of Medical Sciences, in 2010. A new local exhaust ventilation system containing a high efficiency air cleaner system, was designed, constructed, and evaluated in a simulated surgery process. When the distance between the system hood and the pollution sources was 5 cm and the air flow 22 cubic feet per minute, the total surgical smoke was attracted to the system hood at a velocity of 80 feet per minute. In a period of 60 minutes, the cleaning efficiency for particulate agents as well as the gasses and vapors emission was 99.77% indicating that the application of ventilation system prevented the entry of contaminants emission into the operating room. Based on results obtained through simulated surgery process, it was concluded that the ventilation system designed in this study completely blocked the emission of surgical smoke to air of operating room and personnel exposure.

Since nasal respiration is physiologically important, many studies have been conducted to find factors necessitating a change from nasal breathing into oronasal breathing during exercise. The present study tried to understand the role of anterior nasal resistance in this switching. Twelve young, healthy, non-athletic and non-smoker male volunteers with normal body mass index (BMI) were selected after medical examinations. Following anterior rhinomanometry at rest, the subjects participated in an exercise protocol during which ventilation, workload and oronasal switching point (OSP) were measured. The protocol involved a 25 watt increase in workload per minute until the OSP was reached. There were significant correlations between anterior nasal resistance and OSP, workload, and ventilation difference to OSP ratio (P < 0.05). Anterior nasal resistance can be considered as an effective factor on OSP occurrence. In addition, by reducing nasal resistance, one can tolerate longer periods of nasal respiration during exercise.

In order to eliminate and reduce noise in predesigned and installed heating, ventilation, and air-conditioning (HVAC) systems, noise control in HVAC system areas needs to be performed using plenum chambers based on ASHRAE method. A plenum chamber made of galvanized iron was produced based on ASHRAE standards. The length, height, and width of the chamber were 1.5 meters, 1.1 meters and 1.2 meters, respectively. Two input and output openings (40 × 20 cm) were also made. The internal surface of the chamber was lined by 10 cm thick mineral wool with a density of 80 kg/m3. The results show a noise reduction of 2.3 to 13.2 dB with a peak at 250 Hz in 1/1 octave band frequency based on ASHRAE standard method. Generally, highest levels of noise reduction were observed in medium to high frequencies. The most important conclusion revealed by this study is that based on ASHRAE standard, dimensions of the plenum chamber and acoustic specifications of absorbent material applied into the chamber can highly affect the level of noise reduction. In fact, we can change the noise reduction value by changing the dimensions of the plenum. For low frequencies, as said before, it is better to use a bigger plenum chamber.

Numerous studies have been performed on habitual nasal to oronasal breathing switching in exercise. However no investigation has reported quantative comparison between habitual and obligatory nasal to oronasal breathing time in exercise. Twenty healthy non-athlete non-smoker subjects (10 males and 10 females) age 20±2 years were randomly selected and then were exercised in two protocols. In first protocol, they were exercised on ergometer in incremental method of exercise (incrementally graded exercise) until opening of mouth (habitual OSP) occurred, and in second protocol, this incremental exercise on ergometer were done with closed mouth until involuntary opening of mouth occurred (obligatory OSP) and ventilation rate were simultaneously measured in two protocols. The habitual and obligatory OSP were 152.68 ± 11.85 and 464.7 ± 12.88 seconds in males and 157.75 ± 19.64 and 271.43 ± 12 seconds in females, respectively. A significant correlation was showed between habitual OSP and workload, and between obligatory OSP, workload and ventilation differences.: Our data showed that obligatory OSP was longer than habitual OSP in males and habitual OSP is shorter than obligatory OSP in two genders. Also increase of ventilation slope was faster in females than in males.

Teaching some clinical skills to students of medicine and paramedics for the first time on patients is unsafe therefore, a number of skills are primarily practiced on models. This study was conducted in order to determine the effect of practical training in clinical skills center. This quasi-experimental study was performed on 60 students entering the university in 2003-2004. The intervention group received the training on clinical skills (ventilation, laryngoscopy, and tracheal intubation) in clinical skills center before stepping into clinic, but the control group did not receive the training. The performance of the students of both groups was evaluated at the end of the term through direct observation checklist and it was compared in two groups using descriptive test, Chi², and Fisher. The mean score of the investigated skills was compared by t test. The difference of the accuracy rate of the skills of ventilation, laryngoscopy, and tracheal intubation in two groups of intervention and control was significant using Fisher test. In addition comparing the skill of chipset intubation and fixing it in trachea and the manner of fixation and making sure about its placement in two groups revealed a significant difference. Training and practical performance of critical skills on models before performing it on patient may reduce detriments due to lack of proficiency by improving student's abilities.

Aims. According to the nature of surgery operation, every surgery room has different quantity of bioaerosols. In this research, the effect of control systems on bioaerosols in surgery room was investigated. Methods. This is a descriptive-analytical research and studied samples which were seven operating rooms in one of the central hospitals of Tehran city were studied by filtration method with impactor. Sampling was accomplished before and after surgery. The samples immediately transported to laboratory and cultured in agar. After 48 hours of incubation, counting was done. The concentration of bioaerosols is calculated in term of cfu/m3. UVGI performed after finishing the surgery to starting the next, in spectrum of C with 253.7nm. Results. The concentration of bioaerosols before and after surgery was less than the standard in operating time. Also, urology surgery room in all of the conditions had the most quantity of colonies. There was a significant correlation between concentration of bioaerosols and UVGI (p<0.05). Conclusion. Increase the ACH during surgery cause to decrease of bioaerosols content after that.