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Biomedical subjects

G U Meduri

Publications and source records attributed to G U Meduri.

14 recordsLinked to original sources
PubMed1992

Pulmonary manifestations of acquired immunodeficiency syndrome.

In at least 65% of patients with acquired immunodeficiency syndrome (AIDS), the lung is the site for life-threatening illness. To establish a basis for understanding the pulmonary pathology of such illness, we first review briefly the effects of the human immunodeficiency virus on the immune system and then review the pathological pulmonary processes occurring in AIDS in terms of their various etiologies: infections, idiopathic processes, and neoplasia. In the section on each etiology, we discuss clinical manifestations, pulmonary pathology, diagnostic findings, and therapeutic options. In the last section, we outline our overall initial diagnostic approach to the patient with AIDS who presents with respiratory symptoms, and we discuss the integration of clinical, laboratory, and radiographic findings.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Management of bacterial pneumonia in ventilated patients. Protected bronchoalveolar lavage as a diagnostic tool.

We conducted a prospective study to determine the effectiveness of protected bronchoalveolar lavage (PBAL) in diagnosing pneumonia in ventilated patients and the usefulness of bronchoscopic data in treating ventilated patients. Entrance criteria were (1) fever and a new or progressive infiltrate on chest roentgenogram with either leukocytosis or a macroscopically purulent tracheal aspirate, and (2) no antibiotic therapy for at least 48 h before bronchoscopy. Twenty-five ventilated patients met entrance criteria for the study and completed the protocol. PBAL was effective in retrieving distal airway secretions with a minimal degree of contamination as indicated by a specificity and a negative predictive value of 100 percent. Bacterial isolates grew in all patients with pneumonia at a concentration greater than or equal to 100,000 cfu/ml, with a median growth of 500,000 cfu/ml. The presence of a two-log difference between the highest quantitative culture count in patients without pneumonia and the lowest quantitative culture count in patients with pneumonia allowed a clearer determination of a patient's status, with regard to pneumonia, compared with the significant overlap in unprotected BAL. Gram and Giemsa stains of the PBAL were positive in all patients with pneumonia and negative in those without pneumonia. All but one patient with pneumonia received narrow-spectrum antibiotic therapy. All patients without infection had no antibiotic administered. Clinical and roentgenographic criteria could not discriminate between patients with and without pneumonia, confirming the findings of previous investigations. The results of microscopic and culture analyses of the PBAL effluent proved useful in directing antibiotic treatment in patients with pneumonia and in avoiding unnecessary antibiotic use in those patients without pneumonia.

Bacteria↗
PubMed1991

Protected bronchoalveolar lavage. A new bronchoscopic technique to retrieve uncontaminated distal airway secretions.

We tested the effectiveness of protected bronchoalveolar lavage (PBAL), performed through a protected transbronchoscopic balloon-tipped (PBT) catheter, in collecting distal airway secretions with a minimal degree of contamination. The PBAL had less than or equal to 1% squamous epithelial cells in 91% of specimens and an absence of bacterial growth in 59% of patients without pneumonia. Using a threshold of 10(4) cfu/ml we had one false positive result in 33 patient without pneumonia and one false negative in 13 patients with pneumonia. Quantitative bacterial cultures of the PBAL specimens had a diagnostic sensitivity of 97% and a specificity of 92%, with a positive predictive value of 97% and a negative predictive value of 92%. The diagnostic efficiency was 96%. The presence of intracellular organisms in much greater than or equal to 2% of the recovered alveolar cells (Giemsa stain) was seen in all but two patients with pneumonia (on corticosteroids) and in none of the patients without pneumonia. Gram stains of the PBAL specimens were positive in all but one patient with pneumonia and negative in all but one patient without infection (patient with endobronchial narrowing secondary to neoplasm with false positive cultures). Either the Giemsa or the Gram stain was positive in all patients with pneumonia, allowing early and accurate diagnosis of lower respiratory tract infection before the results of cultures were available. The time off antibiotic therapy before bronchoscopy did not affect the result of PBAL cultures, contrary to what we observed for the protected brush specimen.

Anti-Bacterial Agents↗
PubMed1991

Noninvasive face mask mechanical ventilation in patients with acute hypercapnic respiratory failure.

Mechanically assisted intermittent positive-pressure ventilation effectively provides ventilatory support in patients with respiratory failure but it requires placing an artificial airway. We have previously reported our successful experience delivering mechanical ventilation via a face mask (FMMV) rather than with an endotracheal tube in a pilot study of patients with acute respiratory failure. The present investigation evaluated an additional 18 patients with hypercapnic respiratory failure to determine the efficacy of FMMV in a more homogeneous group and to determine factors predicting its success. FMMV was successful in avoiding intubation in 13 of the 18 patients. A significant initial improvement in PCO2 (greater than 16 percent decrease) and in pH (from less than 7.30 to greater than 7.30) predicted success. The five patients who failed on FMMV required endotracheal intubation because of inability to improve gas exchange (three patients), apnea due to sedatives (one patient), and management of secretions (one patient). FMMV was generally well accepted with only two patients withdrawn because of intolerance of the mask. The mean duration of FMMV was 25 h. Complications were seen in only two patients (11 percent): aspiration (one patient) and mild skin necrosis (one patient). Seven patients entered the study by meeting entrance criteria after an unsuccessful extubation attempt and therefore received both forms of mechanical ventilation. All but one patient avoided reintubation, and the face mask proved to be as effective as the endotracheal tube as a conduit for delivering the mechanical tidal volume and improving gas exchange. Our findings indicate that FMMV is a viable option for short-term (one to four days) ventilatory support of patients with hypercapnic respiratory failure and insufficiency.

Acidosis, Respiratory↗
PubMed1991

Fibroproliferative phase of ARDS. Clinical findings and effects of corticosteroids.

Most patients with adult respiratory distress syndrome (ARDS) survive the initial insult which caused respiratory failure only to succumb later to sepsis caused by nosocomial pneumonia or to pulmonary fibrosis. Clinical criteria and analysis of the tracheal aspirate are notoriously inadequate for establishing a diagnosis of ventilator-associated pneumonia. We implemented a comprehensive diagnostic protocol to determine the cause of sepsis in ARDS patients who had been ventilated for more than three days and who had no bronchoscopic evidence of pneumonia. Nine patients with late ARDS who had fever (89 percent), leukocytosis (89 percent), a new localized infiltrate (78 percent), purulent tracheal secretions (89 percent), low systemic vascular resistance (50 percent), and marked uptake of gallium in the lungs (100 percent) had no source of infection identified. Open-lung biopsy specimens from seven patients showed the fibroproliferative phase of diffuse alveolar damage and confirmed absence of pneumonia. Treatment with prolonged high doses of corticosteroids was associated with a marked and rapid improvement in lung injury score (p less than 0.003 at five days). Our findings indicate that the fibroproliferative process occurring in the lungs of patients with late ARDS gives rise to clinical manifestations identical to those of pneumonia and is potentially responsive to steroid treatment.

Adult↗
PubMed1991

Bilateral bronchoalveolar lavage in the diagnosis of opportunistic pulmonary infections.

To further improve the diagnostic value of bronchoscopy in the immunosuppressed population presenting with diffuse pulmonary infiltrates, we prospectively investigated the utility of bilateral bronchoalveolar lavage (BAL). We performed 62 bronchoscopies on 52 immunosuppressed patients. Of the 52 patients, 33 had pulmonary infections. The yield for Pneumocystis carinii pneumonia on bilateral BAL was 94 percent (31/33), compared to the 84 percent (51/61) previously obtained with unilateral BAL in our institution. The recovery of P carinii was unilateral in four of five patients without AIDS and in four of 26 patients with AIDS. Transbronchial biopsy gave a yield of 85 percent (11/13). In ten patients with definitive cytomegalovirus (CMV) pneumonia, recovery of CMV by combined culture and cytology was 100 percent. Of nine bronchoscopies with positive cytology for CMV, five showed cytopathologic changes in the BAL from both sides and four in the BAL from one side only. No complications were seen in the 14 patients with thrombocytopenia or the five patients receiving mechanical ventilation. Our findings indicate that bilateral BAL significantly increases the yield for recovery of P carinii (p less than 0.02) and CMV (p less than 0.001) in immunosuppressed patients.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Noninvasive face mask ventilation in patients with acute respiratory failure.

Noninvasive face mask ventilation has been used successfully in patients with paralytic respiratory failure. This study evaluated whether noninvasive face mask ventilation can be used for patients with acute respiratory failure due to intrinsic lung disease. Six patients with hypercapnia and four with hypoxemic acute respiratory failure met clinical and objective criteria for mechanical ventilation, which was delivered with pressure control and pressure support via a tightly strapped, clear face mask. No patient terminated the study because of inability to deliver adequate ventilation or to improve oxygen exchange; three eventually required endotracheal intubation. The mask was generally well tolerated. All patients had a nasogastric tube placed on suction, and none vomited or aspirated. The mean duration of treatment was 33 h (range, 3 to 88). The physiologic response was considered similar to that which would have been achieved with conventionally delivered ventilation. Noninvasive face mask ventilation may have a role in managing respiratory failure.

Adult↗
PubMed1988

Pulmonary function tests.

The clinical significance of pulmonary function tests (including blood gas analysis) lies in their sensitivity for detecting PCP. PCP has most consistently been found to cause abnormalities in the DLCO and the exercise arterial blood gas; both are highly sensitive for the presence of Pneumocystis infection. These tests are more sensitive for the detection of PCP than are the resting arterial blood gas and chest x-ray. Therefore, measuring these values can be especially helpful in evaluating HIV-infected individuals who have pulmonary symptoms but whose resting arterial blood gas and/or chest radiograph are normal. The advantage of performing the exercise test over measuring the DLCO is that the exercise test is simple. It can be done without pulmonary function equipment and without a technologist. Furthermore, since many AIDS patients with non-PCP pulmonary disorders maintain "normal" exercise tests despite abnormal DLCO, it can be useful in evaluating patients for PCP who have known underlying lung disease with progressive symptoms. Measurement of lung volumes and spirometry lacks both sensitivity and specificity for detecting pulmonary disease in general and PCP in particular. Spirometry is helpful in detecting airways obstruction, which is not an uncommon finding in AIDS patients. The etiology, clinical significance, and treatment of obstructive ventilatory defects in the AIDS population remains unclear.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Pulmonary Kaposi's sarcoma in the acquired immune deficiency syndrome. Clinical, radiographic, and pathologic manifestations.

Pulmonary Kaposi's sarcoma related to the acquired immune deficiency syndrome (AIDS) has not been well characterized. To define the clinical, radiographic, and pathologic features of this entity, 11 autopsy-proved cases of pulmonary Kaposi's sarcoma were reviewed. The most common clinical symptoms were dyspnea and cough, but hemoptysis and stridor were also found. Nodular infiltrates and pleural effusions were the most commonly found radiographic abnormalities. Pulmonary function tests were sensitive in detecting the pulmonary abnormalities due to Kaposi's sarcoma. A low diffusion capacity, lack of arterial desaturation with exercise, and obstruction to airflow were suggestive of pulmonary involvement with this malignancy. Although endobronchial Kaposi's sarcoma was visualized at bronchoscopy as cherry-red, slightly raised lesions, bronchial biopsy specimens always showed no abnormalities. Transbronchial brushings and biopsy specimens and analysis of pleural fluid were also not helpful in establishing a diagnosis. In the seven subjects with extensive parenchymal Kaposi's sarcoma at autopsy, the pleura was always involved. Eight subjects had involvement of the tracheobronchial tree. In all of the subjects, pulmonary Kaposi's sarcoma was a significant cause of morbidity, and in three of 11 subjects (27 percent) it was the direct cause of death.

Acquired Immunodeficiency Syndrome↗