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Biomedical subjects

C A Walawander

Publications and source records attributed to C A Walawander.

27 records · Page 2Linked to original sources
PubMed1992

Prospective evaluation of risk factors for antibiotic-associated bleeding in critically ill patients.

A prospective surveillance program was initiated to determine the relative role of antibiotics containing N-methylthiotetrazole (NMTT) versus patient risk factors in producing antibiotic-associated bleeding. Five hundred forty-six critically ill patients with serum albumin 30 g/L or below were evaluated for evidence of a bleeding event as documented by clinical observation, hemoglobin changes, and transfusions. Bleeding events occurred in 16% of patients receiving an aminoglycoside combination, 10% receiving antibiotics with the NMTT side chain, and 14.5% receiving antibiotics not containing NMTT (p greater than 0.05). The bleeding rate was highest in febrile patients with cancer (14.5%) and lowest in those with a suspected or documented abdominal infection (10%) (p = 0.04), but within each patient group there was no difference among the antibiotics. We conclude that the use of NMTT-containing antibiotics is not an independent risk factor for bleeding, but the role of severity of illness may be underappreciated.

Abdomen↗
PubMed1991

An evaluation of point and interval estimates in population pharmacokinetics using NONMEM analysis.

In a simulation study of the estimation of population pharmacokinetic parameters, including fixed and random effects, the estimates and confidence intervals produced by NONMEM were evaluated. Data were simulated according to a monoexponential model with a wide range of design and statistical parameters, under both steady state (SS) and non-SS conditions. Within the range of values for population parameters commonly encountered in research and clinical settings, NONMEM produced parameter estimates for CL, V, sigma CL, and sigma epsilon which exhibit relatively small biases. As the range of variability increases, these biases became larger and more variable. An important exception was bias in the estimate for sigma V which was large even when the underlying variability was small. NONMEM standard error estimates are appropriate as estimates of standard deviation when the underlying variability is small. Except in the case of CL, standard error estimates tend to deteriorate as underlying variability increases. An examination of confidence interval coverage indicates that caution should be exercised when the usual 95% confidence intervals are used for hypothesis testing. Finally, simulation-based corrections of point and interval estimates are possible but corrections must be performed on a case-by-case basis.

Computer Simulation↗
PubMed1990

A nationwide survey of antibiotic prescribing patterns and clinical outcomes in patients with bacterial pneumonia.

Antibiotic prescribing information was prospectively collected on 1822 hospitalized patients treated for suspected or documented bacterial pneumonia. Antibacterial therapy with a single antibiotic was employed in more than 50 percent of the patients, with cefazolin, cefuroxime, ampicillin, and ceftriaxone sodium representing the most commonly employed agents. Combination therapy using two antibiotics was employed in approximately 30 percent of patients with the aminoglycosides, particularly gentamicin, used extensively. A satisfactory outcome was achieved in approximately 80 percent of patients with a community- or institutional-acquired pneumonia; only 66 percent of nosocomial pneumonias had a satisfactory outcome. An important observation was the apparently common practice of switching patients to an oral antibiotic regimen after an average of seven days of antibiotics and subsequently discharging the patient. No difference was observed in the patterns of clinical response or duration of therapy for culture-positive versus culture-negative patients. The results of this surveillance program can serve as a basis for comparison of institution-specific drug utilization evaluation programs.

Aminoglycosides↗
PubMed1989

The influence of intravenous cimetidine dosage regimens on the disposition of theophylline.

The influence of the method of cimetidine administration on theophylline disposition was studied in nine healthy, cigarette smoking male volunteers. The treatment phases consisted of: A) theophylline alone, B) theophylline plus intermittent cimetidine therapy (300 mg IV every 6 hr), and C) theophylline in combination with continuous infusion cimetidine (50 mg/hr). Theophylline (4.8 mg/kg) was administered intravenously as aminophylline over 30 minutes during each treatment phase. During study phases B and C subjects received 48 hours of cimetidine therapy beginning 24 hours prior to theophylline dosing. Blood samples for determination of theophylline concentrations were collected serially over 24 hours. Serum theophylline concentrations were determined in duplicate using fluorescence polarization immunoassay (Abbott Diagnostic TDx). The average age of the subjects was 27.4 +/- 4.7 years, and the individual smoking histories ranged from 0.5 to 1.5 packs per day (average 0.89 +/- 0.33). The mean (+/- SD) body weight was 79.1 +/- 8.2 kg and all subjects were within 20% of their ideal body weight. Theophylline pharmacokinetic parameters were determined using noncompartmental analysis. ANOVA for repeated measures and Tukey's multiple comparison test were used for statistical analysis. The mean (+/- SD) theophylline clearance for each of the treatment groups was: 1.4 +/- 0.4, 1.2 +/- 0.3, and 1.2 +/- 0.2 ml/min/kg for phases A, B and C, respectively. Cimetidine decreased the clearance of theophylline, however, theophylline clearance was not statistically different between regimens B and C. Thus, the method of cimetidine administration (intermittent versus continuous infusion) did not influence the magnitude of the drug-drug interaction.

Adult↗
PubMed1989

Prospective surveillance of antibiotic-associated coagulopathy in 970 patients.

N-methyl-thio-tetrazole (NMTT) has been proposed as a causative factor in antibiotic-associated coagulopathy. To evaluate this hypothesis, a nationwide surveillance program was initiated to determine the relative frequency of antibiotic-associated coagulopathy and the importance of specific risk factors. A total of 970 patients were studied, with 491 being treated for infections and 479 receiving antimicrobial surgical prophylaxis. The NMTT-containing antibiotic cefotetan was compared with non-NMTT-containing antibiotics, for example, cefoxitin and cefazolin (prophylaxis only), and an aminoglycoside-antianaerobic (AG + AA) combination. Prothrombin time (PT) and partial thromboplastin time (PTT) were measured for each patient prior to the start of antibiotics and within 24-96 hours after the conclusion of drug administration. The patient population was relatively young [mean (SD) age 51.0 (20) yrs] with good nutritional status. The overall frequency of hypoprothrombinemia (4.5%) and bleeding (1.7%) was very low, and was highest with the use of AG + AA (p less than 0.05). No statistical differences were observed for the remaining antibiotic regimens in either the prophylaxis or treatment group. Logistic regression analysis identified treatment with the AG + AA combination, presence of liver disease, and renal dysfunction as factors associated with an increased risk of hypoprothrombinemia. In conclusion, this study suggests that the frequency of antibiotic-associated coagulopathy is low, regardless of antibiotic, in patients who are not critically ill and not malnourished.

Adolescent↗
PubMedDate not supplied

Implementation of a nursing home urinary incontinence management program with and without tolterodine.

OBJECTIVE: To evaluate the implementation of a nursing home urinary incontinence management program. DESIGN: A prospective field trial of the program incorporating practice guidelines and principles of continuous quality improvement. SETTING: Five nursing homes in New York, Virginia, and Georgia PARTICIPANTS: One hundred fifty-one residents identified as being incontinent of urine and who met inclusion criteria for ongoing participation in the program. INTERVENTION: Key multidisciplinary staff from the five nursing homes were trained in the program and assumed responsibility for implementing it in their facilities. The program consisted of a clinical assessment, toileting protocols, and the addition of the antimuscarinic drug tolterodine in selected residents who did not respond well to toileting alone. Data on dryness rates during the 60-day toileting protocols, collected by nursing home staff, were analyzed on a weekly basis by an overall project coordinator who sent data back to the nursing homes in an easy-to-read graphical format. MEASURES: (1) The dryness rate, defined as the number of times the resident was dry divided by the number of times the resident was checked (every 2 hours from 7 a.m. to 7 p.m.); and (2) adverse events (eg, dry mouth, increased confusion, need for dosage reduction). RESULTS: Of 645 residents in the 5 nursing homes, 377 (58%) were identified as incontinent of urine, of whom 151 (40%) were placed on an ongoing toileting program. Of these 151 residents, 48 (32%) were prescribed tolterodine, and 117 (78%) completed the 60-day trial. The initial dryness rate was 57%, and for the group as a whole remained essentially unchanged (increase in dryness 1%, P = 0.50). Among 50 clinically stable residents on a toileting program alone, the increase in the dryness rate was 16% (P = 0.001), and for 31 clinically stable residents prescribed tolterodine, the increase in the dryness rate was 29% (P = 0.012). Two residents had their dosage of tolterodine reduced because of dry mouth and nausea,one resident was taken off the drug because of increased pain in the back and legs and increased confusion. CONCLUSIONS: Overall, this program resulted in significant increases in dryness rates for clinically stable incontinent nursing home residents. These residents represented 22% of the total number of residents identified as incontinent in the five participating nursing homes. Tolterodine was prescribed for approximately one-third of incontinent residents as a supplement to a toileting program, and was well tolerated. Nursing homes should be encouraged to implement similar urinary incontinence programs, target toileting protocols to the most responsive residents, and maintain the program using principles of continuous quality improvement.

Journal Article↗
PubMedDate not supplied

Sepsis syndrome and associated sequelae in patients at high risk for gram-negative sepsis.

We conducted a prospective surveillance study of 80 hospitals across the United States to determine the incidence of sepsis syndrome and its associated sequelae in hospitalized patients over age 18 years who were administered antibiotics for suspected or documented gram-negative infection. A sample of 1754 hospitalized patients were followed from onset of antimicrobial therapy to discharge or death. Mortality rates (MR) varied depending on the suspected source of sepsis syndrome. For patients in whom the syndrome was associated with community-acquired urinary tract infections, mortality was 20% (relative risk [RR] = 0.51, p < 0.05), for those with trauma 20.6% (RR = 0.51, p < 0.05), and patients with nosocomial respiratory tract infections 57.1% (RR = 1.66, p < 0.05). More than two complications occurred in 65.2% of patients under age 60 years (MR 31%), 40.8% of those age 60-80 (MR 42%), and 35.6% of patients older than 80 years (MR 33.3%, p > 0.05). Various patient populations had significant differences in both the incidence of the syndrome and its complications, and consequent mortality. Perhaps morbidity as well as mortality should be used as outcomes when testing the efficacy of innovative therapies for sepsis.

Adolescent↗
PubMedDate not supplied

Symptomatic cardiotoxicity associated with 5-fluorouracil.

A prospective cohort study was conducted in 35 hospitals with oncology units to determine the incidence of symptomatic cardiotoxicity in patients receiving continuous infusions of 5-fluorouracil (5-FU), and to identify risk factors that could contribute to the development of 5-FU-associated cardiotoxicity. A sample of 483 patients [197 (41%) women, overall average age +/- SD 60.9 +/- 11.9 yrs] were followed for one cycle of 5-FU infusion. Thirty-eight (7.9%) patients had abrupt termination of the infusion. There were 9 (1.9%) cases of suspected or documented cardiotoxic events. Cardiotoxicity occurred in 7 (3.35%) of 209 patients receiving their first course of 5-FU and in 2 (0.73%) other patients (p=0.044). Based on univariate analysis, the following patient groups were at elevated risk of cardiotoxicity: those with preexisting cardiac disease (RR=6.83, p=0.0023); patients receiving calcium channel blockers (RR=4.75, p=0.014); those receiving nitrates (RR=9.18, p=0.007); and patients receiving concomitant etoposide (RR=10.32, p=0.022). Patients with underlying cardiac disease require close monitoring while receiving continuous infusions of 5-FU. They should be observed for signs and symptoms of cardiotoxicity, and vital signs should be measured frequently. Continued reporting of 5-FU-associated cardiotoxicity is necessary to identify other patients at risk.

Aged↗