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Biomedical subjects

K V Leeper

Publications and source records attributed to K V Leeper.

29 records · Page 2Linked to original sources
PubMed1993

Diagnosis and treatment of pulmonary infections in adult respiratory distress syndrome.

Nosocomial bacterial pneumonia, or the recently introduced term, "ventilator-associated pneumonia," is a common cause of infection in adult respiratory distress syndrome (ARDS). The presence of ventilator-associated pneumonia in ARDS patients is associated with prolonged ventilatory support and increased mortality rates. Unfortunately, clinical and radiographic diagnoses of pneumonia are sensitive but nonspecific and, at best, select a patient population for which further diagnostic evaluation is warranted. The empiric use of broad-spectrum antibiotics in mechanically ventilated patients without pneumonia may be harmful by facilitating colonization and superinfection with virulent organisms. Recent techniques for sampling lower respiratory tract secretions (protected specimen brushing, bronchoalveolar lavage), via fiberoptic bronchoscopic and nonbronchoscopic guidance have been used to establish improved accuracy in the diagnosis of pneumonia. Although these methodologies are not in widespread use in the ICU setting, the results obtained, when properly performed and with carefully processed specimens, may direct the clinician to the appropriate antibiotic therapy and provide a method of assessing its effectiveness. Moreover, if pneumonia is not confirmed, then an aggressive reevaluation of fever and pulmonary infiltrates in the patient with ARDS is indicated.

Anti-Bacterial Agents↗
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↗
PubMed1992

The diagnosis of acute pulmonary embolism in patients with chronic obstructive pulmonary disease.

The clinical features and noninvasive tests, including ventilation perfusion (V/Q) lung scans, were assessed in 108 patients with chronic obstructive pulmonary disease (COPD) suspected of having pulmonary embolism (PE). Twenty-one (19 percent) of 108 patients had PE. In the majority of patients, it was impossible to distinguish between patients with and without PE by clinical assessment alone. However, when a high clinical index of suspicion was present, PE was confirmed by angiography in three of three patients, but the V/Q scan was of intermediate probability. No roentgenographic abnormalities distinguished between PE and no PE. There was no difference between the alveolar-arterial oxygen gradients in either group, nor was there evidence of a reduction in the PaCO2 in patients with PE who had prior hypercapnia. Among the 108 patients with COPD, high, intermediate, low, and normal/near normal probability scans were present in 5 percent, 60 percent, 30 percent, and 5 percent, respectively. The frequency of PE in these V/Q scan categories was five (100 percent) of five, 14 (22 percent) of 65, two (6 percent) of 33, and zero (0 percent) of five, respectively. In conclusion, in the majority of patients, the V/Q scan diagnosis is usually intermediate and such patients require further investigational studies, including angiography. However, among the few patients who demonstrated a high probability lung scan, there was a high positive predictive value for PE effectively avoiding the need for further studies. In those patients with low probability or near normal/normal V/Q scans, the negative predictive value was not lower than the general hospital population.

Acute Disease↗
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↗
PubMed1988

Treatment of massive acute pulmonary embolism. The use of low doses of intrapulmonary arterial streptokinase combined with full doses of systemic heparin.

The efficacy of low-dose, locally administered streptokinase (SK) combined with full therapeutic systemic doses of heparin was investigated. Seven patients with angiographically proven massive acute pulmonary embolism were treated. Streptokinase, 10,000-20,000 units/hour, was administered directly into the left or right pulmonary artery for 9 to 24 hours. Heparin was administered concurrently. The number of unperfused segments of the infused lung shown on the lung scan decreased from 5 +/- 2 to 2 +/- 1 after 12-24 hours (p less than .01). No change was shown in the contralateral lung. The angiographic index of severity score in the infused lung decreased from 16 +/- 1 to 9 +/- 4 (p less than .01). The partial pressure of oxygen in arterial blood improved within four hours. In spite of the low doses of streptokinase, however, two major bleeding episodes occurred that required blood transfusion. In conclusion, low dose intrapulmonary streptokinase, combined with intravenous heparin, may provide a therapeutic option in patients with life-threatening massive acute pulmonary embolism in whom full dose lytic therapy may be hazardous, although even low dose lytic therapy was associated with risk.

Aged↗
PubMedDate not supplied

Adrenergic crisis from crack cocaine ingestion: report of five cases.

We report the historical, clinical, and laboratory findings in 5 patients after crack cocaine ingestion. All patients exhibited adrenergic crisis as a result of their ingestion. Analysis of their history revealed a latency period before signs and symptoms occurred as well as a wide variation in the number of crack cocaine nuggets ingested. Signs of intoxication were hypertension, tachycardia, hyperthermia, agitation, and generalized seizure activity. Treatment included therapeutic sedation with lorazepam and adrenolysis with esmolol infusion. The majority of patients showed electrocardiographic evidence of cardiac ischemia, but not elevations in serum creatinine phosphokinase enzymes--MB fraction. One patient died of complications associated with subclinical status epilepticus. The toxicities of crack cocaine ingestion are seldom appreciated. Prompt reversal of both cardiovascular and neurological signs and symptoms with appropriate pharmacologic agents is indicated.

Administration, Oral↗
PubMedDate not supplied

A simple technique to reduce ventilator-dependent errors in oxygen consumption measurements.

To evaluate the efficacy of adding a volume reservoir to reduce variability in ventilator-induced fluctuation in inspired oxygen concentration (FiO2) and to reduce oxygen consumption measurement error, we evaluated two ventilators (Puritan-Bennett 7200 and Bear 2) at three inspired oxygen concentrations ranging from 35% to 60%. Continuous sampling of oxygen concentration was conducted for each ventilator. The maximum variability in oxygen concentration was recorded at each minute and oxygen consumption error sensitivity was calculated for both ventilators at three different oxygen concentrations, with and without the use of a baffled 3-L reservoir placed into the inspiratory circuit between the ventilator and test lung. The use of a baffled 3-L reservoir reduced oxygen consumption error sensitivity with the Puritan-Bennett 7200 ventilator at all three oxygen concentrations (p < 0.01). Similar results were found with the Bear 2 ventilator except at the highest FiO2, at which oxygen consumption error sensitivity was not altered. Use of a baffled volume reservoir can significantly reduce ventilator-dependent errors in measuring oxygen consumption via indirect calorimetry. However, when the FiO2 is widely variable, the reservoir is not helpful in reducing error at higher FiO2 concentrations.

Calorimetry, Indirect↗