AIM: To investigate the effect of ambroxol on pulmonary and vascular injury in chronically hypoxic rats. METHODS: 36 male Wistar rats were randomly divided into 3 groups: normal control,chronically intermittent hypoxia(CIH) and ambroxol precaution group(AP).The CIH and AP groups were made into the chronically hypoxic models .The mean pulmonary artery pressure(PAPM) and the levels of plasma superoxide dismutase (SOD) and plasma nitric oxide (NO),lipid peroxide(LPO) were determined. The levels of the lung homogenates SOD, LPO, NO and the changes in pulmonary vascular structure were also examined. RESULTS: The levels of plasma and lung homogenates SOD,NO in CIH group were respectively significantly lower than that of normal control and AP group ( P

AIM: To reproduce hypercapnic models and approach some pathophysiological changes in rats. METHODS: The mixed gases of high concentrated carbon dioxide (8% CO 2, 21% O 2, 71% N 2) were given to wistar rats 7 hours a day for 28 days. The various indexes were compared between control group (group A) and hypercapnic group (group B). RESULTS: The PaCO 2 [(55.90?4.34) mmHg] and the lipid peroxides (LPO) contents in plasma, lung tissue and right ventricle were significantly higher in group B than those in group A ( P

OBJECTIVETo investigate the impact of proportional assist ventilation (PAV) on tolerance and breathlessness in ventilated chronic obstructive pulmonary disease (COPD), and to describe the patient-ventilator interaction, hemodynamic state, breathing pattern and work of breath during PAV and pressure support ventilation (PSV).

METHODSTen intubated COPD patients on weaning from mechanical ventilation were studied. Elastance and resistance were measured by both the inspiratory-hold technique during a brief period of volume control ventilation and runaway technique during PAV. Each assistance level of PAV (80%, 60% and 40%) and PSV was selected randomly. Patients' response, hemodynamics, blood gas and lung mechanics were monitored.

RESULTSTidal volume and respiratory rate didn't change in a consistent manner as the level of assist was decreased (P > 0.05). With the level of assist increasing, peak inspiratory pressure was increasing significantly (P < 0.05), while patients' work of breath had the tendency to decrease (P < 0.05). A significant difference in the Borg Category Scale was observed between PAV and PSV (0.50 [1.50] vs. 0.75 [2.00], P < 0.05) at the same degree of respiratory muscle unloading. PaCO(2) was significantly higher on PAV (54 [23] mm Hg) than on PSV (48 [23] mm Hg) (P < 0.05). Peak inspiratory pressure on PAV was significantly lower than on PSV (16 +/- 4 cm H(2)O vs. 21 +/- 3 cm H(2)O, respectively, P < 0.05). Hemodynamics and oxygenation remained unchanged.

CONCLUSIONSPAV is a feasible method for supporting ventilator-dependent patients and was well tolerated. It can improve the breathing pattern and reduce inspiratory effort. At the same degree of respiratory muscle unloading, PAV can be implemented at much lower peak inspiratory pressure than PSV. It can also apply proportional pressure support according to the patients' ventilatory demand.

Aged ; Blood Gas Analysis ; Female ; Hemodynamics ; Humans ; Male ; Positive-Pressure Respiration ; Pulmonary Disease, Chronic Obstructive ; complications ; Pulmonary Gas Exchange ; Pulmonary Ventilation ; Respiration, Artificial ; methods ; Respiratory Insufficiency ; etiology ; physiopathology ; therapy

Objective To investigate the incidence of in situ thrombosis of small pulmonary arteries and arterioles during the exacerbation stage of chronic cor pulmonale.Methods 49 autopsy cases died from the exacerbation of chronic cor pulmonale were chosen as the study group, while 103 other autopsy cases without chronic cor pulmonale and disseminated intravascular coagulation (DIC) as control group. Morphologic and morphometric studies were taken on lung tissues and other organs with focus on the thrombi in small pulmonary arteries and arterioles.Results 44 cases of the study group had multiple thrombi in small pulmonary arteries and arterioles, the incidence is 89.8%, and in 9 of them, thrombi in proximal pulmonary arteries co-existed, the incidence is 18.4%. 80% of the thrombi existed in pulmonary arterioles. In the control group, only 3 cases had thrombi in small pulmonary arteries and arterioles, the incidence is 2.9%. All thrombi adhered to endangium, implying that they were in situ thrombi. No intravascular thrombosis was found in other organs. X2 test showed that the incidence of thrombosis and the number of thrombi in small pulmonary arteries and arterioles in cases with chronic cor pulmonale were significantly higher than those of the control group (P<0.01).Conclusions Multiple in situ thrombosis in small pulmonary arteries and arterioles is a prominent and common pathological change during the exacerbation stage of chronic cor pulmonale. The study suggests a new diagnostic and therapeutic concept and gives a morphological and theoretical basis for the clinical application of anticoagulants or even the thrombolytic agents for the cases of chronic cor pulmonale in the exacerbation stage.

Objective　To investigate the effects of continuous tracheal gas insufflation (CTGI) combined with biphasic intermittent positive airway pressure (BIPAP) ventilation on dogs with spontaneous breathing. Methods　Eight canine models with oleic acid induced lung injury and spontaneous breathing were ventilated in a random order by Evita 2 (Drager Inc., Germany) in modes of BIPAP (BIPAP group) and BIPAP with CTGI flow rate of 3, 6 and 9?L/min (T3, T6 and T9 groups), respectively. The setting parameters of BIPAP were fiction of inspired oxygen 60%, inspiratory to expiratory ratio 1∶1, respiratory rate 20 and positive end expiratory pressure 5?cm?H2O. Arterial and mixed venous blood gas, lung mechanics, systemic and pulmonary hemodynamics status were monitored at the same level of PaCO2 obtained by adjusting peak inspiratory pressure of BIPAP. Results　Peak inspiratory pressure in the T6 group (14±4?cm?H2O) and in the T9 group (11±3?cm?H2O) were significantly lower than that of BIPAP (20±5?cm?H2O, P<0.01), but there was no significant difference among the T3, T6 and T9 groups or between the T3 and BIPAP groups. PaO2, mean artery blood pressure, mean pulmonary artery pressure, pulmonary artery wedge pressure, cardiac ouput, oxygen delivery and oxygen consumption all remained unchanged in four different conditions. Conclusions　Using BIPAP combined with CTGI does not cause asynchrony between ventilator and spontaneous breathing, but significantly decreases airway pressure with no influence on hemodynamics and oxygenation. Therefore, BIPAP with CTGI may be a useful support technique, especially in cases where the airway pressure should be limited.

OBJECTIVETo estimate the feasibility and the efficacy of early extubation and sequential non-invasive mechanical ventilation (MV) in chronic obstructive pulmonary disease (COPD) with exacerbated hypercapnic respiratory failure.

METHODSTwenty-two intubated COPD patients with severe hypercapnic respiratory failure due to pulmonary infection (pneumonia or purulent bronchitis) were involved in the study. At the time of pulmonary infection control window (PIC window) appeared, when pulmonary infection had been significantly controlled (resolution of fever and decrease in purulent sputum, radiographic infiltrations, and leukocytosis) after the antibiotic and the comprehensive therapy, the early extubation was conducted and followed by non-invasive MV via facial mask immediately in 11 cases (study group). Other 11 COPD cases with similar clinical characteristics who continuously received invasive MV after PIC window were recruited as control group.

RESULTSAll patients had similar clinical characteristics and gas exchange before treatment, as well as the initiating time and all indices at the time of the PIC window. For study group and control group, the duration of invasive MV was (7.1 +/- 2.9) vs (23.0 +/- 14.0) days, respectively, P < 0.01. The total duration of ventilatory support was (13 +/- 7) vs (23 +/- 14) days, respectively, P < 0.05. The incidence of ventilator associated pneumonia (VAP) were 0/11 vs 6/11, respectively, P < 0.01. The duration of intensive care unit (ICU) stay was (13 +/- 7) vs (26 +/- 14) days, respectively, P < 0.05.

CONCLUSIONSIn COPD patients requiring intubation and MV for pulmonary infection and hypercapnic respiratory failure, early extubation followed by non-invasive MV initiated at the point of PIC window significantly decreases the invasive and total durations of ventilatory support, the risk of VAP, and the duration of ICU stay.

Adult ; Aged ; Female ; Humans ; Hypercapnia ; therapy ; Male ; Middle Aged ; Pulmonary Disease, Chronic Obstructive ; complications ; Respiration, Artificial ; methods ; Respiratory Insufficiency ; therapy

OBJECTIVETo investigate the protective effects of beta-carotene in rats against the development of chronic bronchitis induced by cigarette smoking.

METHODSForty-two Male Wistar rats were randomly divided into three study groups: (1) control (n = 15), animals underwent no treatment; (2) cigarette smoking (n = 15), animals developed chronic bronchitis through long-term cigarette smoking twice a day for 75 d; (3) beta-carotene plus cigarette smoking animals (n = 12) were given 1 ml or 15 mg/kg beta-carotene orally every day just before cigarette smoking. The levels of IL-6, IL-8, NO, superoxide dismutase (SOD) and lipoperoxide (LPO) in serum, bronchoalveolar lavage fluid (BALF) and lung tissue were measured and the pathological changes to lung tissue were analyzed using light microscopy.

RESULTSLong-term cigarette smoking caused an obvious increase in the amount of IL-6, IL-8 and LPO and a sharp decrease in the levels of NO and SOD in smoking animals compared to controls. beta-carotene intake reversed all the changes induced by smoking and alleviated the pathological changes caused by chronic bronchitis.

CONCLUSIONSQuantitative oral intake of beta-carotene had protective effects against chronic bronchitis induced by long-term cigarette smoking, which was associated with the increased production of NO, the clearance of some oxidative free radicals (OFR) and the alleviation of chronic inflammation.

Animals ; Bronchitis ; blood ; etiology ; prevention & control ; Interleukin-6 ; blood ; Interleukin-8 ; blood ; Male ; Nitric Oxide ; blood ; Rats ; Rats, Wistar ; Smoking ; adverse effects ; Superoxide Dismutase ; blood ; beta Carotene ; pharmacology