Effects of long-term low-dose oxygen supplementation on the epithelial function, collagen metabolism and interstitial fibrogenesis in the guinea pig lung

Low-frequency ultrasound for pulmonary hypertension therapy

BACKGROUND

Currently, there are no reliable clinical tools that allow non-invasive therapeutic support for patients with pulmonary arterial hypertension. This study aims to propose a low-frequency ultrasound device for pulmonary hypertension therapy and to demonstrate its potential.

METHODS

A novel low-frequency ultrasound transducer has been developed. Due to its structural properties, it is excited by higher vibrational modes, which generate a signal capable of deeply penetrating biological tissues. A methodology for the artificial induction of pulmonary hypertension in sheep and for the assessment of lung physiological parameters such as blood oxygen concentration, pulse rate, and pulmonary blood pressure has been proposed.

RESULTS

The results showed that exposure of the lungs to low-frequency ultrasound changed physiological parameters such as blood oxygen concentration, pulse rate and blood pressure. These parameters are most closely related to indicators of pulmonary hypertension (PH). The ultrasound exposure increased blood oxygen concentration over a 7-min period, while pulse rate and pulmonary blood pressure decreased over the same period. In anaesthetised sheep exposed to low-frequency ultrasound, a 10% increase in SpO2, a 10% decrease in pulse rate and an approximate 13% decrease in blood pressure were observed within 7 min.

CONCLUSIONS

The research findings demonstrate the therapeutic efficiency of low-frequency ultrasound on hypertensive lungs, while also revealing insights into the physiological aspects of gas exchange within the pulmonary system.

Hyperoxia-induced regulation of cough reflex and its effect after antioxidant supplementation

Hyperoxia-induced lung injury is well known in animal and human studies. The respiratory epithelium including sensory nerve endings is a major target for oxidative injury that manifested in lung function changes including cough. On the basis of available information we supposed that hyperoxia alone or in combination with primary lung tissue injury should have a damaging effect on lungs, including the airway nerve endings with the changes in the sensitivity of the central and peripheral neuronal pathways regulating cough. We have previously demonstrated that long-term exposure to 100% oxygen inhibits the cough reflex in cat. This review article summarizes the effect of hyperoxia on the cough reflex in guinea pig model using different concentrations of oxygen and different time of exposure. We also present information on the potential role of antioxidants in reversal of the detrimental effects of hyperoxia on coughing and additional analysis of experiments from previously published studies were obtained and analysed for the cough reflex sensitivity.

Chemotherapy in Non-Small Cell Lung Cancer Patients Receiving Oxygen Therapy

BACKGROUND

Information regarding chemotherapy in non-small cell lung cancer (NSCLC) patients with chronic respiratory failure is limited.

PATIENTS AND METHODS

We retrospectively analyzed patients who received oxygen therapy and underwent chemotherapy for NSCLC at our hospital.

RESULTS

6 patients with NSCLC receiving oxygen therapy (4 with unresectable lung cancer and 2 with postoperative recurrent lung cancer) underwent chemotherapy. 1 patient achieved a partial response and 1 achieved stable disease after first-line chemotherapy. The median overall survival (OS) was 247 days in all patients. Patients with unresectable NSCLC and recurrent NSCLC had median OS times of 282 and 239 days, respectively. Grade 3 lung infection occurred in 4 patients during chemotherapy treatment; however, there were no chemotherapy-related deaths.

CONCLUSION

There is a possibility that chemotherapy could improve the survival of NSCLC patients who receive oxygen therapy.

Adequacy of oxygenation parameters in elderly patients undergoing mechanical ventilation

OBJECTIVE

To compare ideal PaO2 with PaO2 found, ideal PaO2/FiO2 of room air with the one found, and ideal FiO2 with FiO2 found in mechanically ventilated elderly patients.

METHODS

Cross-sectional study that evaluated elderly mechanically ventilated patients for at least 72 hours and who underwent three subsequent blood gas analyses.

RESULTS

The sample consisted of 48 elderly with mean age of 74.77±9.36 years. There was a significant difference between the ideal PaO2 and the one found (p<0.001), between FiO2 corrected and the offered one, and also between ideal PaO2/FiO2 of room air and the PaO2/FiO2 found (p<0,001).

CONCLUSION

A significant increase was seen in PaO2 and FiO2 and in alterations of gas exchange by PaO2/FiO2 index than those found in normal parameters.

A noninvasive [99mTc]DTPA SPECT/CT imaging methodology as a measure of lung permeability in a guinea pig model of COPD

PURPOSE

The purposes of this study are (1) to develop an efficient aerosol inhalation system for the delivery of [(99m)Tc]DTPA aerosol into guinea pig airways with high uniformity for measuring lung clearance using SPECT/CT imaging, as a measure of lung permeability, and (2) to use [(99m)Tc]DTPA studies in guinea pig model of chronic obstructive pulmonary disease (COPD) to determine its usefulness in studying pathogenesis of COPD.

PROCEDURE

We developed an aerosol delivery system and single-photon emission computed tomography (SPECT) imaging method to measure the pulmonary clearance rate in anesthetized guinea pigs. In this system, an 830-cc rebreather exposure chamber was filled with oxygen immediately before a 5 min [(99m)Tc]DTPA (4-5 mCi/mL) aerosol exposure. The rebreather included a top mounted AeroNeb micro pump nebulizer, a nose-only exposure tube, and rear evacuation port. An 830-cc rebreather exposure chamber was filled with oxygen immediately before 5 min [(99m)Tc]DTPA (4 ∼ 5 mCi/mL) aerosol exposure. One control and one cigarette smoking group were studied.

RESULTS

Images showed high and uniform lung deposition and the mean clearance rate was increased by 37% in smoking group.

CONCLUSIONS

The combined SPECT/CT imaging method developed here can be used for serial evaluation of lung function and its response to drug therapy in guinea pig model of COPD.