Diagnostic Fiberoptic Bronchoscopy and Protected Brush Culture: MATERIALS AND METHODS part 2
Contraindications to Bronchoscopy
Absolute contraindications were bleeding abnormalities, severe cardiac disease, acute asthma, and allergy to local anesthetics. High age (>=70 years) and severe hypoxia (PaOz<8kPa) were relative contraindications. Bronchoscopy Procedure Before the bronchoscopy, the patient fasted for at least three hours. Prothrombin value and blood platelets were measured and a blood-gas analysis was performed. The only premedication given was atropine, 0.5 mg intramuscularly, one half hour before the bronchoscopy. During the bronchoscopy, the patient was observed with continuous electrocardiogram, and if necessary, received extra oxygen through a nasal catheter.
Fiberoptic bronchoscopes of several brands were used. Lidocaine was used for topical anesthesia, with spray, 10 mg/ml, for the pharynx and hypopharynx, with injection of 40 mg/ml transorally for the larynx, and with injection through the inner suction channel of the bronchoscope for the bronchial tree. In most patients, a satisfactory anesthesia was obtained with a total dose of lidocaine of about 200 mg. Bronchoscopy was performed with the patient supine, in most cases transorally. Without using the inner channel for suction of secretion, the bronchial tree was inspected and the bronchoscope positioned in the bronchial orifice of the roentgenographically abnormal lobe. A telescoping “double” catheter with the sampling brush protected by a plug was inserted through the inner suction channel, until it could be seen at the tip of the bronchoscope. The inner catheter was then advanced 3 to 4 cm displacing the plug, and by advancing the brush, the specimen could be obtained. The brush was then withdrawn into the inner catheter, the inner catheter into the outer catheter, and the entire catheter was removed from the bronchoscope. An attempt was then made to obtain bronchial secretion by suction through a sterile polyethylene catheter, which had been advanced through the inner channel of the bronchoscope. When this was unsuccessful, 10 to 30 ml of sterile water was injected through the catheter and as much as possible was then re-aspirated. Microbiologic Processing The protected catheter was taken to the bacteriologic laboratory immediately. The end portion of the catheter, first the outer and then the advanced inner catheter, was cleaned with sterile water. The brush was advanced, transected with sterile scissors and placed in a screw-capped glass vial containing 0.2 ml of tryptic soybroth. The vial was vortexed vigorously and 0.01 ml was plated with standard plastic loops on to blood agar, aerobically and anaerobically incubated, and on hematinagar in C02. Since the sampling brush accumulates approximately 0.001 mlu growth of one colony on the plate corresponded to a bacterial concentration of 2 x 104 cfu/ml in the bronchial secretion. Aspirated bronchial secretion, or the small lavage, was cultured for M pneumoniae, Legionella species, and Mycobacteria according to standard methods of the microbiologic laboratories. Both bron¬chial secretion and the PB specimens were also examined for the presence of pneumococcal capsular antigen. Virus isolation was performed according to standard procedures. Definitions of Results Growth of aerobic or anaerobic bacteria > lOVml in the PB specimen, presence of pneumococcal antigen on the PB or in bronchial secretion, or the demonstration of M pneumoniae, Legionella, Mycobacteria, or virus in bronchial secretion were considered significant findings. levitra plus
The results of the PB examination (culture and pneumococcal antigen detection) were divided into four different groups as follow:
(1) True positive: (a) primary useful—a positive finding of value for primary treatment; (b) secondary useful—a positive and significant finding, too late to affect primary treatment, but of importance for continued treatment.
(2) True negative: negative finding because (a) the patient was adequately treated, (b) there was no infection present, or (c) the pathogen could not be demonstrated with the PB-technique.
(3) False negative: a pathogen should have been found.
(4) False positive: contamination of the PB.
Bronchoscopy was considered valuable for the management of the patient if there was a positive finding on the PB and/or in bronchial secretion of importance for the primary or the continued treatment. Also, a true negative finding, both on the PB and in bronchial secretion, was considered valuable for the patient since an already established diagnosis could be supported, or the risk of infection with resistant bacteria or of secondary infection could be excluded.
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