Diagnostic Fiberoptic Bronchoscopy and Protected Brush Culture: DISCUSSION
In this prospective study, we tried to evaluate the usefulness of diagnostic FOB in patients with CAP A significant decline in arterial oxygen pressure (Pa02) is common following FOB, with a subsequent risk of cardiac arrhythmia in particular. This could be especially hazardous in patients with pneumonia, in whom fever, tachycardia, and an already lowered Pa02 are common. However, by adding supplemental oxygen to patients at risk, no cardiac complications were seen in any of our patients, nor were there any other complications, which supports the safety of the bronchoscopic procedure reported earlier.
Injection of lidocaine through the inner channel of the bronchoscope has been claimed to introduce a larger amount of bacterial contaminants into the lower airways than if the anesthesia is performed by nebu- lization. However, Winterbauer et al found injection of lidocaine to be a minor problem if the volume was small (<=3 ml) and if there was no suction through the side channel until the PB culture was obtained.
A transnasal approach has been advocated to minimize the risk of contamination. Although topical anesthesia with lidocaine jelly, 10 mg/ml, was administered, we found it difficult in several patients to pass the inflamed mucous membranes of the nasal cavity without causing pain and sometimes a slight nose bleed. However, no contaminating bacteria were found in any of the PB cultures despite that bronchoscopy was performed transorally, that local anesthetic was injected through the side channel, and in addition, that four patients, by sputum and throat cultures, were found colonized with Gram negative enteric bacteria or Candida at the time of bronchoscopy. We tried to minimize the amount of lidocaine, and we did not aspirate through the side channel before the PB culture was performed. However, the most important factor for avoiding contamination was probably the quantitative culture with a detection level of KPml.
An etiologic diagnosis by noninvasive techniques was obtained in only 13 of the 24 (54 percent) patients, a figure similar to those in earlier studies of CAP. Results from bronchoscopy verified the diagnosis in seven of these, added a pathogen in one patient with a mixed infection, and revealed the diagnosis in a further six patients. Altogether, an etiologic diagnosis was obtained in 79 percent (19 of 24) of the patients undergoing bronchoscopy. viagra plus
In accordance with earlier data, the diagnostic sensitivity of the PB culture was high (four of five) in patients who had not received antibiotics before the bronchoscopy was performed. In the fifth patient (No. 21), growth of S pneumoniae was detected in aspirated bronchial secretion only. Contamination of the bronchoscope tip, or a low-grade colonization with pneu- mococci could explain this finding, but since the clinical picture was in accordance with a pneumococcal pneumonia, the result of the PB examination was considered as possibly false negative. One patient who was found to have a bronchial tumor, had negative cultures.
In contrast, the PB culture was positive in only two of the 17 patients undergoing bronchoscopy because of therapy failure (PB culture not performed in one patient). This figure agrees with earlier studies on patients with CAP However, when taking into account the fact that pneumococcal antigen could be demonstrated from the PB in one further patient and that positive findings were made from aspirated bronchial secretion in five patients (Legionella, 2, M pneumoniaey 1, M tuberculosis, 1, and S pneumoniae, 1, the diagnostic sensitivity with FOB after initiation of antibiotic therapy was as high as 41 percent (seven of 18; one patient had a mixed infection).