Lung
-
Comparative Study
Transient increase in alveolar epithelial permeability induced by volatile anesthesia with isoflurane.
Fifteen patients undergoing surgery and receiving volatile anesthesia with isoflurane were enrolled as the study group. At the same time, 15 patients undergoing surgery with intravenous anesthesia drugs were included as a control group to compare each other. Before surgery, 1 h after surgery, and 1 week after surgery, we investigated these two groups of patients with technetium-99m-labeled diethylene triamine pentaacetic acid radioaerosol inhalation lung scan (DTPA lung scan), a test to evaluate lung ventilation (LV), which was evaluated by the first and equilibrium lung ventilation image and alveolar epithelial permeability (AP) which was evaluated by the half time (T1/2, minutes) of Tc-99m DTPA radioaerosol lung clearance. ⋯ In addition, no significant change in AP before surgery (T1/2 = 64.0 +/- 17.3 min), 1 h after surgery (64.5 +/- 19.6 min), or 1 week after surgery (63.6 +/- 17.6 min) was found among the control group patients (p values > 0.05). However, a significant transient increase in AP was found in the study group 1 h after surgery (71.7 +/- 17.5 versus 51.2 +/- 16.4 min), but it recovered 1 week after surgery (51.2 +/- 16.4 versus 70.9 +/- 16.0 min) (p values < 0.05). We conclude that volatile anesthesia with isoflurane can induce transient increase of AP.
-
Regional effects of the chest wall on airway pressure transmission were studied during high frequency ventilation in anesthetized rabbits. We measured airway pressure (Paw), esophageal pressure (Pes), and costal pleural pressure (Ppl) by a rib capsule and flow and volume with a calibrated pneumotachograph. Using a closed circuit, pressures and flow were measured at varying frequencies (2-80 Hz) and tidal volumes (2-20 ml). ⋯ By contrast, the phase difference between Paw and Pes and its variability were relatively small. These differences in Pes from Ppl responses might be caused by a difference in the impedance of the airway-mediastinum pathway or a direct transmission of tracheal pressure oscillations to the esophagus. The former suggests that constraints offered by the mediastinum and rib cage resulted in nonuniform ventilation during high frequency ventilation.
-
Allergen exposure in atopic asthmatic patients is associated with recruitment and activation of eosinophils in the airways. Once activated, eosinophils release toxic products, including the eosinophil cationic protein (ECP), able to damage bronchial structures and to increase bronchial hyperresponsiveness. With this background, the present study was designed to evaluate whether ECP levels in bronchoalveolar lavage (BAL) fluid could reflect, better than BAL eosinophil counts, the cellular activation that follows allergen exposure in atopic asthmatics. ⋯ However, in this latter group, a weak positive correlation was demonstrated between eosinophil percentages and delta Mch, i.e., the increased non-specific bronchial reactivity, which is observed after allergen challenge (r = 0.55; p < 0.05). Thus, in stable asthmatic patients an ongoing activation of eosinophils parallels their migration, but this eosinophilic inflammation is not strictly related to bronchial reactivity to Mch. By contrast, after allergen inhalation challenge, eosinophil recruitment and activation seem to follow different temporal kinetics, and eosinophilic inflammation may be partially associated with the degree of airway hyperresponsiveness.
-
Comparative Study
Serial observations after high dose talc slurry in the rabbit model for pleurodesis.
The mechanisms leading to a pleurodesis after the intrapleural injection of a sclerosing agent are not completely understood. The purpose of the present study was to make serial observations over 28 days on the pleural fluid findings and the gross and microscopic changes in the pleura after talc slurry administered intrapleurally at a high dose. Sixty-six rabbits received 400 mg/kg talc slurry. ⋯ At 28 days there was a clinically significant pleurodesis in all rabbits; pleurodesis was not observed before this time. From this study we conclude that the intrapleural injection of 400 mg/kg talc slurry leads to an acute exudative pleural effusion and clinically significant pleurodesis that is present on day 28 but not day 14. It appears that the production of a pleurodesis requires higher doses of talc in rabbits without a chest tube than in humans with a chest tube.
-
The aim of this study was to evaluate the effects of halothane, enflurane, isoflurane, and sevoflurane on slowly adapting pulmonary stretch receptor (SAR) activity in dogs. Eight beagles were anesthetized with an intravenous injection of a mixture of urethane and alpha-chloralose as a basal anesthesia, then vagotomized, artificially ventilated, and chest opened. Single afferent activities from SARs were recorded from the peripheral nerve cut end of the left vagus. ⋯ Discharges of high threshold SARs tended to decrease with increasing anesthetic level; however, no statistical significance was observed at any anesthetic level. Only one exception to these changes was observed at 1 MAC of halothane where no significant decrease in the expiratory discharge of low threshold SARs or significant increase in the discharge of high threshold SARs was induced against a control value. In conclusion, recent inhalation anesthetics, except for halothane at the light anesthetic level, tended to decrease SAR activities depending on the anesthetic level, suggesting attenuation of the Hering-Breuer inflation reflex.