Underwater acoustic sensing using the geometric phase.

We present a sensing modality using the geometric phase of acoustic waves propagating in an underwater environment. We experimentally investigate the effect of scattering by a small subwavelength perturbation on a flat submerged surface. We represent the state of an acoustic field in the unperturbed and perturbed cases as multidimensional vectors. The change in geometric phase is obtained by calculating the angle between those vectors. This angle represents a rotation of the state vector of the wave due to scattering by the perturbation. We perform statistical analysis to define a signal-to-noise ratio to quantify the sensitivity of the geometric phase measurement and compare it to magnitude based measurements. This geometric phase sensing modality is shown to have higher sensitivity than the magnitude based sensing approach.

Antibiotic therapy in preterm premature rupture of membranes: a randomized, prospective, double-blind trial.

The use of antibiotics in the management of preterm, premature rupture of membranes remains controversial. By use of a prospective randomized double-blind design we investigated the maternal-fetal benefits associated with antibiotic therapy in 85 women with premature rupture of membranes at 34 weeks' estimated gestational age. In the treatment group 40 patients received intravenous mezlocillin for 48 hours followed by oral ampicillin until delivery. In the control group 45 patients received intravenous and oral placebo. Patients who received antibiotics had chorioamnionitis and endometritis less frequently than the control group (p less than 0.01 and p less than 0.05). Pathologic examination of the placentas showed a lower incidence of chorioamnionitis in the treatment group (p less than 0.05). The period from premature rupture of membranes to delivery (latency) was prolonged with antibiotics (p less than 0.05) and resulted in significant weight gain in the infants in the antibiotic group (p less than 0.0001). These infants also had higher 1- and 5-minute Apgar scores. Clinically suspected sepsis, respiratory distress syndrome, intraventricular hemorrhage, perinatal death rate, and prolonged hospitalization (greater than 30 days) were also increased in the control group.

Treatment of serious urinary tract infections at a university teaching hospital: a retrospective chart review.

A retrospective chart review of all adult patients treated empirically for urinary tract infections (including pyelonephritis) with parenteral antibiotics over a 3-month period was conducted at this university teaching hospital. A total of 92 patient charts were located and reviewed. All patients had a complicating condition. Blood cultures were obtained on 67% of the patients; 23% were positive. E coli was the primary infecting organism (56%). All organisms tested against ceftriaxone and amikacin were found to be sensitive. Only 38% of isolates were sensitive to ampicillin. Empiric ceftriaxone therapy was used in 70% of the cases. The average length of parenteral therapy was 3.8 days. Based on the results of this study, the following recommendations were made: blood cultures should be obtained in all patients; the use of ampicillin alone should be avoided due to the drug's poor activity against isolated urinary pathogens; and ceftriaxone should be used for empiric therapy in the majority of patients, including diabetics, due to the drug's excellent activity against isolated urinary pathogens.

Multidisciplinary approach to cost reduction of C-section prophylaxis.

Runaway cefoxitin costs prompted a thorough usage evaluation by the P & T Committee, the antibiotic review subcommittee, and the pharmacy department at this 450-bed teaching hospital. C-section prophylaxis accounted for 25% of all cefoxitin usage. With the assistance of the ob/gyn department, a major campaign was initiated to alter prescribing habits and evaluate more cost effective prophylaxis. Single dose cefotetan replaced multidose cefoxitin regimen for a 6-month trial basis. Annualized cost savings for drug and supplies were approximately $49,086, and no change in morbidity was noted. The ob/gyn department then agreed, at the request of the antibiotic subcommittee, to conduct a trial comparing single dose cefotetan with single dose cefazolin in women undergoing C-section. The results indicated that both treatments were equally effective, consequently, cefazolin replaced cefotetan, producing an additional $10,384 annual savings. Overall, our approach to C-section cost reduction resulted in a total of $59,470 annual savings and demonstrated the effectiveness of an organized multidisciplinary approach.

Development and implementation of a comprehensive, criteria-based drug-use review program.

A comprehensive drug-use review (DUR) program based on established criteria for use of each drug is described. The DUR program was developed to promote cost-effective drug therapy and satisfy Joint Commission on Accreditation of Hospitals standards for drug-use evaluation. Antibiotic and ambulatory-care drug-use subcommittees composed of physicians, pharmacists, nurses, and clinical laboratory personnel were formed as advisory groups to the pharmacy and therapeutics (P&T) committee. The subcommittees review overall drug-use patterns in their respective areas monthly and investigate the use of specific problem drugs. Drug-use reviews have been facilitated by the implementation of a mandatory antibiotic order form and pharmacy computer systems. Nonformulary drug use is monitored. The procedure for adding drugs to the formulary was modified to require the submission of specific criteria for appropriate drug use; when a drug is added to the formulary, the criteria for use are also adopted. The program has been successful in curtailing inappropriate drug use, reducing drug expenditures, and integrating P&T committee decisions into daily pharmacy practice. The implementation of this DUR program has enabled the P&T committee to conduct ongoing, systematic, criteria-based drug-use evaluations.