Assessment of Bronchodilator Response in Children with Asthma Exacerbation Using the Respiratory Resistance Values

Sixty-four pediatric patients with asthma exacerbation were studied. The children were subjected to respiratory resistance evaluation using the Airflow Perturbation Device (APD) and spirometry evaluation. They were then administered albuterol and 15 minutes later the APD and spirometry evaluations were repeated. Eleven of the children could not perform spirometry. The APD results demonstrated that respiratory resistance of the patients decreased by about 20%, indicating that the APD could detect the expected response to bronchodilator. However, no similar conclusion could be made with the spirometry parameters (FVC, FEV1, FEV1/FVC, and FEF25% - 75%) performed on the same patients. The differences on the spirometry parameters did not change significantly before and after bronchodilator administration. Furthermore, these differences were negligibly increased or decreased for some with no consistency between the FVC, FEV1, FEV1/FVC, and FEF25% - 75%. Even though all the children were clinically improved after albuterol administration and discharged home, this could not be demonstrated by spirometry data. This study validates previous reports that spirometry is not a reliable pulmonary diagnostic tool for young children, as spirometry is highly effort-dependent and requires a substantial degree of patient cooperation. APD on the other hand is a reliable, simple, effortless diagnostic tool that can be utilized in evaluation and management of children with asthma symptoms and exacerbation.

Respiratory Mechanics, Respiratory Muscle Strength, Control of Ventilation and Gas Exchange in Patients with Autoimmune Liver Disease

Objectives: To assess respiratory elastance and resistive properties in patients with autoimmune liver disorders using the passive relaxation expiration technique and compare findings to a group of patients with non-autoimmune liver disease and control subjects. These findings were then related to control of ventilation and gas exchange. A secondary objective was to assess respiratory muscle strength and gas exchange and their relation to respiratory mechanics. Methods: Measurements included respiratory elastance and resistance using the passive relaxation method. Pulmonary function, gas exchange and control of ventilation were assessed using standard methods. Results: a) Compared to control subjects, Ers in patients with liver disease was on average 50% greater than in controls;b) mean respiratory resistance, expressed as the respiratory constants, K1 and K2 in the Rohrer relationship, Pao/V’ = K1 + K2V’, was not different from control resistance;c) mean maximal inspiratory and maximal expiratory pressures averaged 36% and 55% of their respective control values;d) inspiratory occlusion pressure in 0.1 sec (P0.1) was increased and negatively associated with FVC;and e) increases in P0.1, mean inspiratory flow (Vt/Ti) and presence of respiratory alkalosis confirmed the increase in ventilatory drive. Despite inspiratory muscle weakness in patients, P0.1/Pimax averaged 5-fold higher than in control subjects. Conclusions: Despite inspiratory muscle weakness and a V’E similar to that in normal subjects, central drive is increased in patients with chronic liver disease. The increase in ventilatory drive is related to smaller lung volumes and weakly associated with increase in respiratory elastance. Findings confirm that P0.1 is a reliable measure of central drive and is an approach that can be used in the evaluation of control of ventilation in patients with chronic liver disease.

Design of a Low Respiratory Resistance Mask for COVID-19

Observational evidence suggests that mask-wearing mitigates transmission of COVID-19;at the same time high respiratory resistance leads to an unwillingness to wear masks.This paper proposed a respiratory drive structure to reduce the air resistance of a mask.This structure provides different shapes during expiration and inspiration while focusing on filtering dust,bacteria,or viruses.Meanwhile,the assembled system on the mask can be disassembled and replaced.Then porous media simulation is used to verify the model effect.Experimental results of a new mask show that the ventilation resistance is reduced by 20%,and the bacterial filtration efficiency meets the requirements of YY 0469–2011.

Immediate Respiratory Response to Electronic Cigarette Use

Background: Electronic cigarettes were originally designed to reduce adult dependency on normal cigarettes and as a tobacco cessation tool to substitute traditional cigarettes. But it has become the most popular among teenagers. Rationale: To investigate the immediate adverse respiratory effect of short-term electronic cigarette vapor inhalation. Method: Twenty-five subjects were randomly selected and used in this study. The respiratory resistance values were evaluated and used for comparison. The subjects were asked to breathe into the Airflow Perturbation Device (APD) for evaluation of their respiratory resistance before vaping (in triplicate). The same subjects, a minute later, were then asked to use one poke (3 seconds) of the e-Cigarette device to inhale e-Cigarette vapor with nicotine from a pod with 59 mg/ml nicotine. Immediately following the e-Cigarette use, their respiratory resistance was measured again (in triplicate). Results: Comparing the respiratory resistance values before and immediately after exposure to e-Cigarette vapor showed that their respiratory resistance increased almost immediately. Conclusion: Although there are long-term studies showing that the e-Cigarette is as harmful as regular cigarettes, this study showed a nearly immediate effect of using the e-Cigarette that significantly increased the respiratory resistance of the user. Very short exposure time to e-Cigarette vapor (3 seconds only), caused an immediate adverse physiologic effect in respiratory resistance.

Gene typing and antibiotic resistance of methicillin- resistant Staphylococcus aureus isolated from lower respiratory tract at two hospitals in Shanghai

Objective To study the genotyping characteristics and antibiotic resistance of methicillin-resistant Staphylococcus aureus(MRSA)isolated from lower respiratory tract at 2 different level hospitals in Shanghai.Methods The subjects included 155 patients at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014,including 108 males and 47 females,with a mean age