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Biomedical subjects

K V Leeper

Publications and source records attributed to K V Leeper.

At least 19 recordsLinked to original sources
PubMed2000

Epidemiology of chronic bronchitis and acute infective exacerbations of chronic bronchitis.

Acute exacerbations of chronic bronchitis (AECBs) are one of the major causes of morbidity and mortality in the United States, resulting in significant cost to the health care system. Epidemiological information on chronic bronchitis is abundant and has been collected in most industrialized countries. The epidemiology of AECB, however, is less forthcoming. The causes of AECB are multifactorial and include environmental pollutants, allergic responses, and viral and bacterial infections. The role of bacterial infection in AECB is controversial but is believed to account for half of AECB. Because the medical and economic implications of treatment failure in these patients are substantial, an aggressive approach to stratify and treat these patients is necessary. Epidemiological data on chronic bronchitis and acute infective exacerbations of chronic bronchitis will allow us to more precisely define the role of bacterial infection in AECB, and this information may help guide antimicrobial therapy.

Journal Article↗
PubMed1998

Nosocomial sinusitis in patients in the medical intensive care unit: a prospective epidemiological study.

A prospective observational cohort study of nosocomial sinusitis was carried out in two medical intensive care units. Sinusitis was diagnosed by computed tomographic scanning and the culture of sinus fluid obtained by puncture of a maxillary sinus. Clinical and epidemiological data were collected at the time of admission to the unit and daily thereafter. Specimens from the nares, oropharynx, trachea, and stomach were cultured on admission and daily thereafter. The cumulative incidence of nosocomial sinusitis was 7.7%, and the incidence rates were 12 cases per 1,000 patient-days and 19.8 cases per 1,000 nasoenteric tube-days. Risk factors for nosocomial sinusitis, as determined by multiple logistic regression analysis, included nasal colonization with enteric gram-negative bacilli (odds ratio [OR], 6.4; 95% confidence interval [95% CI], 2.2-18.8; P = .007), feeding via nasoenteric tube (OR, 14.1; 95% CI, 1.7-117.6; P = .015), sedation (OR, 15.9; 95% CI, 1.9-133.5; P = .011), and a Glasgow coma score of < or = 7 (OR, 9.1; 95% CI, 3.0-27.3; P = .0001).

Cohort Studies↗
PubMed1998

Epidemiology of ventilator-acquired pneumonia based on protected bronchoscopic sampling.

We performed a prospective observational cohort study of the epidemiology and etiology of nosocomial pneumonia in 358 medical ICU patients in two university-affiliated hospitals. Protected bronchoscopic techniques (protected specimen brush and bronchoalveolar lavage) were used for diagnosis to minimize misclassification. Risk factors for ventilator-associated pneumonia were identified using multiple logistic regression analysis. Twenty-eight cases of pneumonia occurred in 358 patients for a cumulative incidence of 7.8% and incidence rates of 12.5 cases per 1, 000 patient days and 20.5 cases per 1,000 ventilator days. Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Hemophilus species made up 65% of isolates from the lower respiratory tract, whereas only 12.5% of isolates were enteric gram-negative bacilli. Daily surveillance cultures of the nares, oropharynx, trachea, and stomach demonstrated that tracheal colonization preceded ventilator-associated pneumonia in 93.5%, whereas gastric colonization preceded tracheal colonization for only four of 31 (13%) eventual pathogens. By multiple logistic regression, independent risk factors for ventilator- associated pneumonia were admission serum albumin <= 2.2 g/dl (odds ratio [OR] 5.9; 95% confidence interval [CI] 2.0-17.6; p = 0.0013), maximum positive end-expiratory pressure >= 7.5 cm H2O (OR, 4.6; 95% CI, 1.4 to 15.1; p = 0.012), absence of antibiotic therapy (OR, 6.7; 95% CI, 1.8 to 25.3; p = 0.0054), colonization of the upper respiratory tract by respiratory gram-negative bacilli (OR, 3.4; 95% CI, 1.1 to 10.1; p = 0.028), pack-years of smoking (OR, 2.3 for 50 pack-years; 95% CI, 1. 2 to 4.2; p = 0.012), and duration of mechanical ventilation (OR, 3. 4 for 14 d; 95% CI, 1.5 to 7.8; p = 0.0044). Several of these risk factors for ventilator-associated pneumonia appear amenable to intervention.

Anti-Bacterial Agents↗
PubMed1996

Scintigraphic lung scans and clinical assessment in critically ill patients with suspected acute pulmonary embolism.

PURPOSE: The purpose of this investigation was to evaluate the diagnostic accuracy of radionuclide scintigraphic lung scans and clinical assessment in critically ill patients with suspected acute pulmonary embolism. MATERIALS AND METHODS: Critically ill patients were defined as follows: (1) patients who were hypoxemic on room air, and not given ventilatory support (n = 89); (2) patients given ventilatory support (n = 46); and (3) patients in ICUs, but not given ventilatory support (n = 85), and hypotensive patients who were not hypoxemic or given ventilatory support (n = 3). Comparisons were made with patients who had none of these characteristics of critically ill patients (n = 627). Data are from the Prospective Investigation of Pulmonary Embolism Diagnosis. RESULTS: The sensitivities, specificities, and positive predictive values of high probability lungs scans among each of the four categories of critically ill patients were not statistically significantly lower than values in noncritically ill patients. The positive predictive values of the clinical assessments did not differ to a statistically significant extent from noncritically ill patients. Clinical assessment, when concordant with the lung scan interpretation, usually increased the positive predictive value for pulmonary embolism. CONCLUSION: Scintigraphic lung scans and clinical assessment retain their diagnostic value even in critically ill patients.

Acute Disease↗
PubMed1996

Ventilator-associated pneumonia due to Pseudomonas aeruginosa.

OBJECTIVE: Ventilator-associated pneumonia (VAP) caused by Pseudomonas aeruginosa has been associated with higher case fatality rates than VAP caused by other bacterial etiologies. The causes of this excess mortality are unclear. DESIGN: Retrospective review of 38 consecutive ventilated patients with Pseudomonas pneumonia, documented by highly reliable methods. Charts of five additional patients were unavailable for review. SETTING: Medical ICUs of a university-affiliated Veterans Affairs Medical Center and a university-affiliated municipal hospital. MEASUREMENTS: Prospectively collected hospital admission acute physiologic and chronic health examination (APACHE) II scores and cause of ICU admission. Retrospectively calculated organ failure and APACHE scores, VAP score. Clinical and microbiologic variables. Antibiotic treatment and outcome. Direct cause of death by standard definitions. RESULTS: Overall mortality was 69% (26/38), significantly higher than the APACHE II predicted mortality of 42.6% (p=0.037). At least 38% (10/26) of deaths were directly attributable to Pseudomonas VAP. Multivariate analysis of factors associated with death found infectious cause for ICU admission (odds ratio [OR]=8.67; 95% confidence interval [CI], 0.86 to 85.94) and number of organ dysfunctions on the day of diagnosis (OR=1.73, 95% CI, 1.02 to 2.92) were significant. Septic shock from Pseudomonas VAP, septic shock from subsequent infection, and multiple organ dysfunction syndrome were the most common immediate causes of death. Mortality increased linearly with increasing APACHE III score on the day of diagnosis. Of initial antibiotic regimens, 67% (26/36) were considered failures. Persistent pneumonia occurred in 35% of patients while recurrent pneumonia was unusual (1/38). CONCLUSIONS: Development of Pseudomonas pneumonia results in a mortality rate in excess of that due to the presenting illness. The attributable mortality determined by several means appears to approach 40%. The excess mortality appears to be related to the host defense response to the pneumonia rather than any characteristic of the pneumonia. Even standard antibiotic regimens fail frequently and do not prevent the excess mortality. Since at least 38% of deaths can be directly attributable to the Pseudomonas pneumonia, improvement in therapy is needed.

APACHE↗
PubMed1996

Noninvasive positive pressure ventilation in status asthmaticus.

OBJECTIVE: In asthmatic patients with acute respiratory failure (ARF), placing an endotracheal tube is associated with a high rate of complications and results in increased airway resistance. In acute asthma, mask-continuous positive airway pressure (CPAP) decreases airway resistance and the work of breathing (WOB), but does not improve gas exchange. In COPD with ARF, adding intermittent positive pressure ventilation to mask-CPAP results in an additional improvement in WOB and is highly effective in correcting gas exchange abnormalities. In our medical ICU, noninvasive positive pressure ventilation (NPPV) is used as first-line interventional therapy in eligible patients with hypercapnic ARF. We report our experience with NPPV in 17 episodes of asthma and ARF over a 3-year period. METHODS: A face mask was secured with head straps, avoiding a tight fit, and connected to a ventilator (PB-7200). Initial ventilatory settings included CPAP at 4 +/- 2 cm H2O to offset intrinsic positive end-expiratory pressure and pressure support ventilation (PSV) at 14 +/- 5 cm H2O aiming at a respiratory rate less than 25 breaths/min and an exhaled tidal volume of 7 mL/kg or more. PSV was then adjusted following arterial blood gas results. RESULTS: Mean age was 35.4 +/- 11.3 years; 10 patients were female. The mean (+/- SE) for different physiologic values are reported at initiation, less than 2 h, 2 to 6 h, and 12 to 24 h into NPPV. pH was 7.25 +/- 0.01, 7.32 +/- 0.02 (p = 0.0012), 7.36 +/- 0.02 (p < 0.0001), and 7.38 +/- 0.02; PaCO2 was 65 +/- 2, 52 +/- 3(p = 0.002), 45 +/- 3(p < 0.0001), and 45 +/- 4; PaO2 fraction of inspired oxygen was 315 +/- 41, 403 +/- 47, 367 +/- 47, and 472 +/- 67 (p = 0.06); and respiratory rate was: 29.1 +/- 1, 22 +/- 1 (p < 0.0001), 20 +/- 1, and 17 +/- 1. NPPV was well tolerated, and only two patients required sedation. Initial delivered minute ventilation was 16 +/- 4 L/min. The mean (+/- SD) peak inspiratory pressure to ventilate in the NPPV-treated patients was 18 +/- 5 cm H2O and always less than 25 cm H2O. There was no complication or problem with expectorating of secretions. Oral intake (liquid diet) was preserved. Two patients required intubation (35 min and 89 h into NPPV) for worsening PaCO2. Duration of NPPV was 16 +/- 21 h. All patients survived. Length of hospital stay was 5 +/- 4 days. CONCLUSIONS: In asthmatic patients with ARF, NPPV via a face mask appears highly effective in correcting gas exchange abnormalities using a low inspiratory pressure (< 25 cm H2O). A randomized study is in progress to assess fully the role of NPPV in status asthmaticus.

Adult↗
PubMed1996

Severe community-acquired pneumonia.

Severe community-acquired pneumonia is a distinct clinical entity usually requiring intensive care unit (ICU) management. Among community-acquired pneumonia (CAP) requiring hospital admission, approximately 10% will receive ICU care and the mortality rate ranges from 21% to 47%. Host-related factors, clinical presentation, laboratory and radiographic findings on admission are useful in identifing the patient at high risk for fulminant pneumonia. The most common organisms responsible for severe CAP are Streptococcus pneumoniae, Haemophilus influenzae, gramnegative bacilli, Legionella pneumophilia and Staphylococcus aureus, but depending on host-related and epidemiological factors, the cause of severe CAP can be expanded to include tuberculosis, viruses, fungi, Pneumocystis carinii. An aggressive diagnostic approach that results in retrieval of adequate lower respiratory tract sample and incorporates both cultural and noncultural techniques is important in rapidly establishing the cause of pneumonia and allowing for the initiation of appriopiate and effective antimicrobial therapy. Empiric therapy should cover the most common organisms responsible for severe CAP in the community; however, every attempt should be made to continue to assess epidemiologically which organisms are responsible for pneumonia. Currently, studies focusing on bolstering the immune system are being conducted and may eventually be used in conjunction with antimicrobial to reduce the mortality of severe CAP.

Community-Acquired Infections↗
PubMed1995

Successful treatment of amoxapine-induced refractory status epilepticus with propofol (diprivan)

Tonic-clonic seizure activity is a recognized complication of amoxapine overdose. Refractory drug-induced status epilepticus is associated with significant morbidity and mortality. Standard regimens for controlling status epilepticus may be ineffective for aborting drug-induced seizures. The authors report the case of a 30-year-old woman who presented with an amoxapine overdose that deteriorated into status epilepticus refractory to conventional therapy. Propofol given by intravenous bolus and maintenance infusion successfully halted the patient's seizure activity. This case suggests that propofol may be effective as an anticonvulsant in refractory drug-induced status epilepticus.

Adult↗
PubMed1995

Ventilator-associated Pseudomonas aeruginosa pneumonia: radiographic findings.

PURPOSE: To characterize the radiographic features of ventilator-associated Pseudomonas aeruginosa pneumonia (PAP). MATERIALS AND METHODS: In 56 patients (40 men and 16 women), PAP was documented with fiberoptic bronchoscopy. All patients underwent mechanical ventilation for at least 48 hours before diagnosis. The findings on chest radiographs were recorded. In eight patients in whom computed tomography (CT) was performed, results were compared with radiographic findings. RESULTS: Twenty-six patients with adult respiratory distress syndrome (ARDS) had diffuse bilateral confluent opacities; 30 patients without ARDS had multifocal opacities. In 13 patients, cavities were detected at chest radiography, CT, or both. Seven of 29 patients with pleural abnormalities had empyema. CT provided important additional information (presence of cavities or effusions) in four cases. CONCLUSION: Findings on chest radiographs are nonspecific for PAP. The frequencies of cavities and empyema are surprisingly low, perhaps owing to prompt diagnosis and therapy.

Bronchoscopy↗
PubMed1995

Using noninvasive tests and thrombolytics for pulmonary embolism.

Obstructed pulmonary circulation from an embolism results in dilatation of the right ventricle, which becomes hypokinetic. The subsequent decline in forward cardiac output leads to diminished left ventricular preload. Combined with the reduction in the size of the left ventricular cavity from the flattening of the septum, there is a fall in total systemic cardiac output.

Humans↗
PubMed1995

Community-acquired pneumonia in the intensive care unit.

CAP requiring ICU admission is a distinct clinical entity. The mortality rate of pneumonia in this subset of patients has been unchanged in the past several years. Aggressive diagnostic of strategies to establish the causative pathogens of pneumonia rapidly will enable clinicians to adjust antibiotic therapy appropriately. It is hoped that new adjunctive therapeutic options that positively influence host-related factors and bolster pulmonary antibacterial defense will result in reduced morbidity and mortality.

AIDS-Related Opportunistic Infections↗
PubMed1994

Treatment of severe pneumonia in hospitalized patients: results of a multicenter, randomized, double-blind trial comparing intravenous ciprofloxacin with imipenem-cilastatin. The Severe Pneumonia Study Group.

Intravenously administered ciprofloxacin was compared with imipenem for the treatment of severe pneumonia. In this prospective, randomized, double-blind, multicenter trial, which included an intent-to-treat analysis, a total of 405 patients with severe pneumonia were enrolled. The mean APACHE II score was 17.6, 79% of the patients required mechanical ventilation, and 78% had nosocomial pneumonia. A subgroup of 205 patients (98 ciprofloxacin-treated patients and 107 imipenem-treated patients) were evaluable for the major efficacy endpoints. Patients were randomized to receive intravenous treatment with either ciprofloxacin (400 mg every 8 h) or imipenem (1,000 mg every 8 h), and doses were adjusted for renal function. The primary and secondary efficacy endpoints were bacteriological and clinical responses at 3 to 7 days after completion of therapy. Ciprofloxacin-treated patients had a higher bacteriological eradication rate than did imipenem-treated patients (69 versus 59%; 95% confidence interval of -0.6%, 26.2%; P = 0.069) and also a significantly higher clinical response rate (69 versus 56%; 95% confidence interval of 3.5%, 28.5%; P = 0.021). The greatest difference between ciprofloxacin and imipenem was in eradication of members of the family Enterobacteriaceae (93 versus 65%; P = 0.009). Stepwise logistic regression analysis demonstrated the following factors to be associated with bacteriological eradication: absence of Pseudomonas aeruginosa (P < 0.01), higher weight (P < 0.01), a low APACHE II score (P = 0.03), and treatment with ciprofloxacin (P = 0.04). When P. aeruginosa was recovered from initial respiratory tract cultures, failure to achieve bacteriological eradication and development of resistance during therapy were common in both treatment groups (67 and 33% for ciprofloxacin and 59 and 53% for imipenem, respectively). Seizures were observed more frequently with imipenem than with ciprofloxacin (6 versus 1%; P = 0.028). These results demonstrate that in patients with severe pneumonia, monotherapy with ciprofloxacin is at least equivalent to monotherapy with imipenem in terms of bacteriological eradication and clinical response. For both treatment groups, the presence of P. aeruginosa had a negative impact on treatment success. Seizures were more common with imipenem than with ciprofloxacin. Monotherapy for severe pneumonia is a safe and effective initial strategy but may need to be modified if P. aeruginosa is suspected or recovered from patients.

Adult↗
PubMed1994

Corticosteroid rescue treatment of progressive fibroproliferation in late ARDS. Patterns of response and predictors of outcome.

Pulmonary fibroproliferation (PFP) is directly or indirectly the leading cause of death in patients with late ARDS. We previously reported our experience using intravenous corticosteroids (IVC) in 8 patients with late ARDS and now have expanded our observation to a total of 25 patients with severe fibroproliferation (mean lung injury score [LIS] 3) and progressive respiratory failure (RF). Thirteen patients had open-lung biopsy before treatment. Patients were started on IVC treatment (IVCT) an average of 15 +/- 7.5 days into mechanical ventilation (MV). Significant physiologic improvement (SPI) to IVCT was defined as a reduction in LIS of greater than 1 point or an increase in PaO2:FIO2 ratio of greater than 100. We observed three patterns of response: rapid responders (RR) had an SPI by day 7 (n = 15); delayed responders (DR) had an SPI by day 14 (n = 6); nonresponders (NR) were without SPI by day 14 (n = 4). Overall the following significant mean changes were seen within 7 days of IVCT: LIS from 3 to 2 (p = 0.001), PaO2:FIO2 from 162 to 234 (p = 0.0004), PEEP from 11 to 6.8 cm H2O (p = 0.001), chest radiograph score from 3.8 to 3.0 (p = 0.009), and VE from 16 to 13.6 L/min (p = 0.01). Development of pneumonia was related to the pattern of response. Surveillance bronchoscopy was effective in identifying pneumonia in eight afebrile patients. Nineteen of 25 (76 percent) patients survived the ICU admission. Comparisons were made between survivors (S) and nonsurvivors (NS) and among the three groups of responders. At the time ARDS developed, no physiologic or demographic variable could discriminate between S and NS. At the time of IVCT, only liver failure was more frequent in nonsurvivors (p = 0.035). Histologic findings at open-lung biopsy and pattern of physiologic response clearly predicted outcome. The presence of preserved alveolar architecture (p = 0.045), myxoid type fibrosis (p = 0.045), coexistent intraluminal bronchiolar fibrosis (p = 0.0045), and lack of arteriolar subintimal fibroproliferation (p = 0.045) separated S from NS. ICU survival rate was 86 percent in responders and 25 percent in nonresponders (p = 0.03). Only one death resulted from refractory respiratory failure.

Adult↗
PubMed1994

Causes of fever and pulmonary densities in patients with clinical manifestations of ventilator-associated pneumonia.

BACKGROUND: Ventilator-associated pneumonia, a leading cause of sepsis in patients with acute respiratory failure, is difficult to distinguish clinically from other processes affecting patients receiving mechanical ventilation. We conducted a prospective study of patients with suspected ventilator-associated pneumonia to identify the causes of fever and densities on chest radiographs and to evaluate the diagnostic yield and efficiency of tests used alone and in combination. METHODS: The 50 patients entered into the study underwent a systematic diagnostic protocol designed to identify all potential causes of fever and pulmonary densities. Diagnoses responsible for fever were established by strict diagnostic criteria for 45 of the 50 patients. The prevalence of specific conditions and diagnostic yield of individual tests were used to formulate a simplified diagnostic protocol. RESULTS: The diagnostic protocol identified 78 causes of fever (median 2 per patient). Infections were the leading causes of fever and pulmonary densities. Of the 45 patients with fever, 37 had one or more infections identified (67 sources). Most infections (84 percent) were one of four types:pneumonia, sinusitis, catheter-related infection, or urinary tract infection. Ventilator-associated pneumonia occurred in only 42 percent. All but nine infections (87 percent) were directly or indirectly related to insertion of a catheter or a tube. Concomitant infections were frequent (62 percent), particularly in patients with sinusitis (100 percent), catheter-related infections (93 percent), and pneumonia (74 percent). Of concomitant infections, 60 percent were caused by a different pathogen. Noninfectious causes of fever were more common in the 22 patients with adult respiratory distress syndrome. Histologically proved pulmonary fibroproliferation was the only cause of fever in 25 percent of patients with adult respiratory distress syndrome. Radiographic densities were caused by an infection in only 20 patients (19 pneumonia, 1 empyema). In more than 50 percent of the 25 patients without adult respiratory distress syndrome, congestive heart failure, and atelectasis were the sole causes of pulmonary densities, and fever always originated from an extrapulmonary site of infection. Used in combination, bronchoscopy with protected sampling, computed tomographic scan of the sinuses, and cultures of maxillary sinus aspirate, central intravenous or arterial lines, urine, and blood identified 58 of the 78 sources of fever (74 percent). CONCLUSIONS: The observations in this study document the complex nature of acute respiratory failure and fever and underscore the need for accuracy in diagnosis. The frequent occurrence of multiple infectious and noninfectious processes justifies a systematic search for source of fever, using a comprehensive diagnostic protocol. A simplified diagnostic protocol was devised based on the diagnostic value of individual tests.

Adult↗
PubMed1994

Noninvasive mechanical ventilation via face mask in patients with acute respiratory failure who refused endotracheal intubation.

OBJECTIVE: To evaluate the response to noninvasive ventilation in a group of terminally ill patients with acute respiratory failure who refused endotracheal intubation. DESIGN: Case series. SETTING: Medical intensive care units (ICUs) in a university health science center. PATIENTS: Eleven patients, nine with hypercapnic and two with hypoxemic acute respiratory failure. Mean age of patients was 64 yrs. INTERVENTION: Mechanical ventilation was delivered via a face mask. The initial ventilatory setting was continuous positive airway pressure mode, with pressure-support ventilation of 10 to 20 cm H2O, titrated to achieve a respiratory rate of < 25 breaths/min and a tidal volume of 5 to 7 mL/kg. Ventilatory settings were adjusted based on results of arterial blood gases. Mean duration of mechanical ventilation was 44 hrs. MEASUREMENTS AND MAIN RESULTS: Mechanical ventilation via face mask was effective in correcting gas exchange abnormalities in seven of 11 patients, all of whom survived and were discharged from the ICU. Four patients with hypercapnic acute respiratory failure died. Mechanical ventilation via face mask was effective in improving respiratory acidosis in three patients and had no effect in one patient. Two of the four patients could not be weaned from mechanical ventilation and opted for discontinuation of this method. Removal of the ventilator while retaining the mask for oxygen supplementation was a nontraumatic experience to the patient and family. Even when respiratory failure did not resolve, mechanical ventilation via face mask was effective in lessening dyspnea and allowed the patient to maintain autonomy and continuous verbal communication. CONCLUSIONS: We conclude that mechanical ventilation via face mask offers an effective, comfortable, and dignified method of supporting patients with end-stage disease and acute respiratory failure.

Acute Disease↗
PubMed1993

Pneumonia and ARDS in patients receiving mechanical ventilation: diagnostic accuracy of chest radiography.

This study was done to evaluate the diagnostic accuracy of bedside chest radiography for pneumonia, adult respiratory distress syndrome (ARDS), or both in patients receiving mechanical ventilation. The series consisted of 40 patients; diagnostic accuracy was defined as the area under the receiver operating characteristic curve. Overall diagnostic accuracy for ARDS was 0.84. Overall diagnostic accuracy for pneumonia was 0.52. Review of previous radiographs and knowledge of clinical data did not enhance diagnostic accuracy for ARDS or pneumonia. Diagnostic accuracy for pneumonia was minimally reduced when ARDS was present. There was an increase in false-negative results because the diffuse areas of increased opacity in ARDS obscured the radiographic features of pneumonia. The authors conclude that chest radiography is of limited value for the diagnosis of pneumonia in patients receiving mechanical ventilation. The high false-negative and false-positive ratings for pneumonia resulted in a low diagnostic accuracy. The high diagnostic accuracy for ARDS was primarily due to the well-defined radiographic appearance of ARDS and few false-positive ratings.

Adolescent↗