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Query: UMLS:C0032285 (pneumonia)
 54,520 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The respiratory pathophysiology of A2 influenza infection was studied in mice treated with small-particle aerosols (SPA) of rimantadine or ribavirin. Untreated infections in mice resulted in survival rates of 15% or less and were characterized by (i) severe hypoventilation (decreased P(O2) and increased P(CO2)), (ii) compensated respiratory acidosis (increased P(CO2) and HCO(3) (-), with normal pH), (iii) pneumonia with increased ratio of wet/dry lung weight, and (iv) hypothermia. Treatment with SPA of rimantadine (21 mg/kg per day for 4 days) beginning 72 h after virus challenge significantly improved survival rate (80%) but failed to alter lung pathology from that found in infected, untreated mice. Rimantadine treatment decreased somewhat the severity of hypoventilation, respiratory acidosis, lung wet weight, hypothermia, and lung virus titers from that observed in infected, untreated mice. SPA of ribavirin (26 mg/kg per day for 4 days) initiated 6 h after SPA exposure of mice to virus significantly improved survival rate (95%) and reduced lung virus titers and lung pathology. Gas exchange and pulmonary edema in ribavirin-treated, infected mice were significantly improved over those of infected, untreated controls. The mechanisms for increased survival rates induced by SPA of rimantadine remain uncertain, since increased survival rates could not be ascribed entirely to improvements in lung functions. In contrast, however, ribavirin treatment appeared to improve survival rates by reducing major lung pathology and pulmonary dysfunction. This was probably mediated through the antiviral effects of ribavirin.
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PMID:Effects of small-particle aerosols of rimantadine and ribavirin on arterial blood pH and gas tensions and lung water content of A2 influenza-infected mice. 1 87

Adult respiratory distress syndrome (ARDS) is a common medical emergency in respiratory care complicating a great variety of traumas and diseases. An animal model from Lewe miniature pigs has been developed to study the ARDS under standardized conditions; it is based on aspiration pneumonitis, a disorder often observed in ARDS, injuring the lung alveolar surfactant system. The experimental study was conducted under neuroleptanalgesia. ARDS was produced by intratracheal application of hydrochloric acid (0.2 mol/l) in an amount of 1.0 ml/kg body wt. The animals were ventilated automatically by a standardized ventilatory pattern in IPP mode. In all animals the time course of oxygenation ratio (Pa,O2/F1O2), arterial CO2 tension (Pa,CO2), ratio of alveolo--arterial oxygen tension difference to inspired oxygen fraction (Aa,DO2/F1O2), oxygen exchange ratio ((AaDO2/Pa,O2), lung compliance (CL), inspiratory airway resistance (RrsI), dead space ratio VD/VT), pulmonary artery pressure (PAP) and systemic blood pressure were studied. Changes in quasi-static volume--pressure curves, percentage change in lung water content and gross pathological finding were used to integrate the findings into a system of pathophysiological changes in ARDS. The animal group to which hydrochloric acid was administered shows severe pulmonary distress leading to death within 3.5--7.5 h. No significant changes in the measured parameters could be observed in the control group over a 14 h period. The results suggest that aspiration pneumonitis in Lewe miniature pigs is very suitable to investigate various problems in pathogenesis of ARDS. The model provides reproducible results which correlate very well with findings in different ARDS states. The models serves both to compare clinical states and to search for newer therapeutic manoeuvres.
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PMID:Gas exchange, pulmonary mechanics and haemodynamics in adult respiratory distress syndrome: experimental results in Lewe miniature pigs. 49 31

The indices of P a-A CO2, P A-a O2 and VD/VT were evaluated in a group of children treated with controlled ventilation (IPPV) for: pneumonia, congenital heart disease, respiratory distress syndrome or central nervous system diseases. The P A-a O2 index is regarded as the most useful one, since it enables the possibility to select a F IO2 value for obtaining an optimal P aO2. For calculation of VD/VT according to Bohr's formula during connection of the child to respirator P ECO2 was determined planimetrically from the capnographic curve. P a-A CO2 was recognized as a less useful index and difficult to interpret.
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PMID:Evaluation of P a-A CO2, P A-a O2 and VD/VT measurements during controlled respiration in children. Preliminary communication. 79 76

Patients with neurological disorders may have a reduced ventilatory response to a rising PaCO2. This is often unpredictable and may become apparent only when other complications, e.g. infections (pneumonia), occur or when the patient is subjected to general anaesthesia. This paper described a simple method suitable for screening patients who may have an impaired capacity of eliminating CO2 when stressed. Ventilatory changes were determined during the continuous recording of the CO2 concentration in end-tidal air in 20 healthy subjects, who were breathing first air and then gas mixtures containing 21% O2 and 2.5 or 5% CO2. A prediction interval with 90 and 95% probability limits was constructed for healthy individuals. The normally expected change in minute ventilation per m2 body surface area per change in PACO2 (delta versicle E/m2, l/min/delta PACO2, for this technique is also given.
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PMID:A simple technique for the determination of the ventilatory response to rising arterial CO2 tensions, suitable for patients with neurological disorders. 106 79

Pneumonia was induced in rats by instillation of carrageenin (0.5 ml of 0.7% solution) into the trachea. Three or four days after instillation, the lungs were isolated, perfused with blood of healthy rat blood donors, and ventilated with air + 5% CO2 or with various hypoxic gas mixtures. Pulmonary vascular reactivity to acute hypoxic challenges was significantly lower in lungs of rats with pneumonia than in lungs of controls. The relationship between O2 concentration in the inspired gas and Po2 in the blood effluent from the preparation was shifted significantly to lower Po2 in lungs with pneumonia compared to control ones. These changes were not present in rats allowed to recover for 2-3 weeks after carrageenin instillation. We suppose that blunted hypoxic pulmonary vasoconstriction may contribute to hypoxaemia during acute pulmonary inflammation. Decreased Po2 in the blood effluent from the isolated lungs with pneumonia implies significant increase of oxygen consumption by the cells involved in the inflammatory process.
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PMID:Acute pneumonia reversibly inhibits hypoxic vasoconstriction in isolated rat lungs. 128 78

In patients with severe adult respiratory distress syndrome, mechanical ventilation may not be able to ensure gas exchange sufficient to sustain life. We report the use of an intravenous oxygenator (IVOX) in five patients who were suffering from severe adult respiratory distress syndrome as a result of aspiration, fat embolism, or pneumonia. IVOX was used in an attempt to provide supplemental transfer of CO2 and O2 and thereby reduce O2 toxicity and barotrauma. All patients were tracheally intubated, sedated, and chemically paralyzed and had a PaO2 < 60 mmHg when the lungs were ventilated with an FIO2 = 1.0 and a positive end expiratory pressure of > or = 5 cmH2O. The right common femoral vein was located surgically, and the patient was systemically anticoagulated with heparin. A hollow introducer tube was inserted into the right common femoral vein, and the furled IVOX was passed into the inferior vena cava and advanced until the tip was in the lower portion of the superior vena cava. IVOX use ranged from 2 h to 4 days. In this group of patients, IVOX gas exchange ranged from 21 to 87 ml x min-1 of CO2 and from 28 to 85 ml x min-1 of O2. One of the five patients survived and was discharged from the hospital. The IVOX transferred up to 28% of metabolic gas-exchange requirements. One patient with a small vena cava showed signs of caval obstruction. Three other patients demonstrated signs of a septic syndrome after the device was inserted.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Clinical trials of an intravenous oxygenator in patients with adult respiratory distress syndrome. 834 37

In 1980 we stopped using extracorporeal membrane oxygenation for adults because only 1 of 20 patients treated between 1973 and 1979 survived. In October 1988 we returned to adult extracorporeal life support (ECLS) with a modified protocol including venovenous access when possible, large oxygenators for CO2 clearance, activated clotting time of 180 to 200 seconds, and case selection based on 90% mortality (30% transpulmonary shunt). Of 19 patients referred, 14 met criteria for ECLS. Three of these 14 patients with isolated respiratory failure died before ECLS could be started, and 1 patient refused ECLS and died. Ten were placed on ECLS for 2 to 24 days. Indications were pneumonia (3), post-cardiac operation (2), and adult respiratory distress syndrome (5). Five recovered and 5 died. The cause of early death was progressive pulmonary injury (3), hemorrhage (1), and ventricular arrhythmia (1). One late death occurred at 3 months secondary to intraabdominal complications related to liver transplantation. In conclusion, 10 adult patients with severe respiratory failure were treated with extracorporeal life support; 5 patients recovered lung function and 4 of these patients survived and were discharged to home. Surviving patients were typically younger and were placed on ECLS early in their disease process, emphasizing that early intervention is one key factor to a successful outcome.
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PMID:Early experience with adult extracorporeal membrane oxygenation in the modern era. 155 60

The Lahey Clinic experience using laser bronchoscopy for relief of obstructive tracheobronchial lesions during a 7-year period from 1982 to 1989 involves 269 patients treated with 400 procedures. The carbon dioxide (CO2) laser was used for tracheal stenosis and granulation tissue. The neodymium:yttrium-aluminum-garnet (Nd:YAG) laser was used for all obstructing endobronchial neoplasms. Indications for therapy included severe dyspnea, hemoptysis, and postobstructive pneumonitis. All patients had relatively central lesions. A rigid bronchoscope was used to treat 88% of patients, and 12% of patients were treated with a flexible bronchoscope. One death occurred during the intraoperative period. Eleven deaths occurred within 1 week of therapy and were related to the presence of extensive malignant lesions or to coronary artery disease. Our experience indicates that bronchoscopic application of the CO2 or Nd:YAG laser affords effective palliation for patients with obstructive tracheobronchial lesions. The Nd:YAG laser is recommended for patients with bulky vascular endobronchial neoplasms, and the CO2 laser is best reserved for patients with benign tracheal stenosis and granulation tissue.
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PMID:Endoscopic laser therapy for obstructing tracheobronchial lesions. 170 56

We hypothesized that the ventilatory capacity needed to wean from mechanical ventilation (mv) depends on two variables: ventilatory endurance and the efficiency of gas exchange. We also hypothesized that these variables could be assessed from data readily available at the bedside, including tidal volume (VT) on mv and during spontaneous breathing (sb), ventilator peak inspiratory pressure (Ppk), and patient negative inspiratory pressure (NIP). Ventilatory endurance was evaluated using a modified pressure-time index: PTI = TI/Ttot x Pbreath/NIP, where Pbreath = Ppk x VTsb/VTmv. Defining VE40 as the minute ventilation needed to bring PaCO2 to 40 mm Hg, the efficiency of gas exchange was evaluated by calculating VE40/VTsb = (VE x PaCO2)mv/VTsb x 40. Because high levels of inspiratory effort might cause patients to reduce VTsb and thereby compromise CO2 elimination, we devised a weaning index (WI) that combines ventilatory endurance and the efficiency of gas exchange: WI = PTI x (VE40/VTsb). The study population comprised 38 patients with chronic obstructive pulmonary disease, adult respiratory distress syndrome, pneumonia, neuromuscular disease, and miscellaneous other conditions. They had been mechanically ventilated more than 3 days and were considered by clinical criteria to be ready for weaning. Of 46 weaning trials, 19 were successful, 2 were partially successful, and 25 failed. PTI and VE40/VTsb were higher in patients who failed (p less than 0.05), but neither variable alone had sufficient sensitivity or specificity to predict the outcome of weaning trials accurately.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of a new weaning index based on ventilatory endurance and the efficiency of gas exchange. 189 91

We studied the energy metabolism of ALS patients under mechanical ventilation and tube feeding. Gas exchanges (O2 and CO2 content in expiratory and inspiratory gas) were measured all day long by DELTATRAC (Datex, Finland) in 11 ALS patients, and energy metabolism during 24 hours was calculated according to the next formula; 5.67 VO2 + 1.60 VCO2-2.17 UN (VO2; O2 consumption l/min, VCO2; CO2 production l/min, UN; urea nitrogen excretion in urine g/day). All patients were clinically stable under continuous mechanical ventilation and tube feeding, and did not have any infection such as pneumonia. The patients were 23-70 years old (mean 49.3), and had total clinical courses of 3-12 years (mean 7.1), and 2-8 year-long courses under mechanical ventilation (mean 4.6). They were classified into the next 3 groups: group I; totally locked-in state (2 patients), group II; complete tetraplegia (6 patients), group III; incomplete tetraparesis (3 patients). Basal metabolic rate (BMR) of each patient was also calculated from Harris-Benedict's formula; male = 66.47 + 13.75W + 5.0H - 6.76A, female = 665.10 + 0.567W + 1.85H - 4.68A (W; weight kg, H; height cm, A; body surface area m2). And the changes of the body weight by month were examined retrospectively in 26 ALS patients with at least 2 year-duration under mechanical ventilation, which include the previous 11 patients. The calorie consumption of 24 hours were 783.3 kcal (group I), 875.3 (group II), 974.9 (group III), which were all lower than BMR (I; -26.8%, II; -17.6%, III; -11.3%).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Energy metabolism of ALS patients under mechanical ventilation and tube feeding]. 190 43


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