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PubMed1992

State of the art: regional anesthesia using anesthetic admixtures.

Aging, high-risk, and ambulatory patients comprise a growing population of surgical candidates. The advantages of regional anesthesia for these patients has promoted technological and pharmacological advances. As new anesthetic agents are developed, methods to improve existing local anesthetics continue. This article reviews the current practice of local anesthetic admixtures. The physiological action of the local anesthetics and their additives is explained relative to their chemical properties. The advantages and risks when adding bicarbonate and epinephrine are described. Nursing implications for the care of the patient receiving regional anesthesia using admixtures are reviewed. An actual case report is presented to demonstrate the clinical application of local anesthetic admixtures.

Action Potentials↗
PubMed1991

Stability of cefotaxime sodium and metronidazole in an i.v. admixture at 8 degrees C.

The stability of cefotaxime and metronidazole in i.v. admixture at 8 degrees C was studied. The commercially available injectable formulation of cefotaxime sodium 1 g was diluted to 5 mL with 0.9% sodium chloride injection and added to metronidazole injection 500 mg/100 mL. A 2-mL sample was removed and diluted to 100 mL with water. Thirty 1-mL portions were transferred to glass vials and refrigerated at 8 degrees C. At 0, 1, 2, 4, 8, 12, 24, 36, 48, and 72 hours after the admixture was prepared, the vials were removed, placed in a refrigerated autosampler, and assayed for cefotaxime and metronidazole concentrations by stability-indicating high-performance liquid chromatography. Over the 72-hour study period, the concentration of cefotaxime remaining at all assay times was 95.91-101.13% of the initial concentration. The concentration of metronidazole remaining at each assay time was 93.08-102.19% of the initial concentration. Cefotaxime sodium 10 mg/mL and metronidazole 5 mg/mL were stable for 72 hours at 8 degrees C in an i.v. admixture prepared from commercially available injectable formulations.

Cefotaxime↗
PubMed1989

Temperature of refrigerated i.v. fluids and admixtures during infusion.

The effects of infusion rate, drop size, and solution composition on the infusion temperature of i.v. fluids and admixtures that had been stored at refrigerated temperatures were determined. Polyvinyl chloride bags containing 5% dextrose injection, 0.9% sodium chloride injection, cefazolin 20 mg/mL in 5% dextrose injection, or total parenteral nutrient (TPN) solution were removed from the refrigerator after 12 hours and hung from i.v. poles. An administration set was attached to each bag, and the distal end of the administration tubing was placed in a beaker-funnel-flask apparatus that served as a collection vessel for effluent during simulated i.v. infusions. Thermo-couples were inserted into each i.v. bag and positioned under the distal end of each administration set to monitor the temperatures of the solution in the bag and of the effluent. 5% Dextrose injection and 0.9% sodium chloride injection were studied at two flow rates (125 and 60 mL/hr) using two different administration sets (60-drops/mL microdrip set and 15-drops/mL primary set); the cefazolin admixture and the TPN solution were studied at both flow rates using the primary set only. The temperatures at each probe were measured in triplicate at the start of each infusion and at 3, 6, 9, 12, 15, and 25 minutes during the infusion; each infusion was repeated three times. All of the solutions warmed significantly as they passed through the administration sets. Throughout all time intervals, the cefazolin admixtures had the smallest proximal-distal temperature increase, and the TPN solutions had the greatest increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Cefazolin↗
PubMed1989

Stability of esmolol hydrochloride and sodium nitroprusside in intravenous admixtures.

The stability of esmolol hydrochloride and sodium nitroprusside in an admixture containing both drugs was studied. Solutions containing sodium nitroprusside in a final concentration of approximately 200 micrograms/mL and esmolol hydrochloride in a final concentration of 10 mg/mL in 5% dextrose injection were prepared in a 250-mL volumetric flask. The flask was wrapped with a light-protective cover, stored at ambient room temperature (15-30 degrees C), and protected from light. All experiments were conducted in triplicate with samples taken at 0, 2, 4, 8, and 24 hours. Testing included measurement of pH and absorbance at 400 and 600 nm. High-performance liquid chromatography was used to measure esmolol hydrochloride and sodium nitroprusside concentrations. No changes were observed in the physical appearance, pH, or absorbance of the admixtures. Neither the esmolol hydrochloride nor the sodium nitroprusside concentrations varied by more than 4% during the study. Under the conditions studied, esmolol hydrochloride is compatible with sodium nitroprusside in an admixture containing both drugs.

Adrenergic beta-Antagonists↗
PubMed1986

Stability of Liposyn II fat emulsion in total nutrient admixtures.

Compatibility and safety of a safflower oil-soybean oil lipid emulsion (Liposyn II, Abbott) with amino acids and dextrose in total nutrient admixtures (TNAs) were studied. Sixty-two admixtures representing 31 different combinations of fat emulsion, amino acid injection, and dextrose injection were tested. Both 10% and 20% concentrations of the fat emulsion and three concentrations each of amino acid injection and dextrose injection were used; the core admixture components were placed in empty flexible plastic bags in three different sequences: fat, amino acids, dextrose; fat, then dextrose and amino acids simultaneously; and amino acids and dextrose simultaneously, then fat. One of two mixtures of electrolytes and trace metals was added to each sample at the end of mixing. Six samples were tested after one day at 25 degrees C, 35 after two days at 5 degrees C plus one day at 30 degrees C, and 21 after nine days at 5 degrees C plus one day at 25 degrees C. Multivitamin injections were added to each TNA just before the 24-hour room-temperature storage. pH, emulsion particle size, and zeta potential (electrostatic surface charge of lipid particles) were measured after visual inspection of each sample. Amino acids were separated by high-performance liquid chromatography and measured. Dextrose was measured by size-exclusion chromatography. In a controlled study of 24 dogs, six-hour infusions of TNAs containing Liposyn II 20% were administered for 14 days, after which all major organs and tissues were studied microscopically. At all storage times in the compatibility study, all TNAs retained a uniform, milk-like appearance.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1988

[Determination of iodine-containing admixtures in semisynthetic penicillins].

Dependence of the values defining the content of iodine sorbing admixtures in semisynthetic penicillins on pH, reaction time and drug aliquots was studied. On the basis of this study a general approach to development of procedures for determining iodine sorbing admixtures in semisynthetic penicillins was suggested. Procedures for determination of iodine sorbing admixtures in carbenicillin, carfecillin, ampicillin, oxacillin, azlocillin and ampiox were developed.

Adsorption↗
PubMedDate not supplied

Nasal admixture during mouth breathing in awake normal subjects.

We tested the flow-impeding properties of the nasopharynx in 27 healthy subjects with normal nasal resistance (mean +/- SD: 2.45 +/- 1.92 cmH20.l-1 X s). While the subjects inspired and expired deliberately through a rubber mouth-piece, a tight-fitting nose-mask was supplied with 100% O2 from a filled 30-1 rubber bag. Recording instantaneous FEO2 at the mouth was a sensitive indicator of whether nasal flow was present during the preceding inspiration. On a theoretical basis, we are describing a method of calculating the mean percentage of nasal admixture during inspiration. Fluctuations in FEO2 in relation to time revealed varying nasal flow in some individuals. The mean nasal admixture differed considerably between all subjects (mean +/- SD: 20.9 +/- 16.5%; range: 1-70%), showing no correlation to nasal resistance. Five of 27 subjects with a history of habitual mouth breathing had a significantly lower nasal admixture (2.5 +/- 1.7% vs 25.1 +/- 15.4%; p less than 0.005), with no statistical difference in nasal resistance. Present data indicate that upper airway patency is variable in normals during voluntary mouth breathing. We suggest that habitual mouth breathing with absence of nasal obstruction may be associated with velopharyngeal narrowing.

Adult↗
PubMed1987

Monitoring waste in an intravenous admixture program.

A method for collecting and analyzing data on i.v. admixture waste is described, and examples of the use of these data to reduce waste are presented. In 1984, a pharmacy department serving 580 hospital beds projected annual expense for waste of i.v. products to be nearly $30,000. Five major changes were implemented to reduce waste. Modification of expiration dating policies for cefoxitin and tobramycin substantially reduced waste. After an operating room pharmacy satellite was opened, decreased waste of dobutamine, dopamine, nitroglycerin, and nitroprusside was estimated to save $1000 per year. Changing times of batch processing of i.v. admixtures resulted in cost savings that were not significantly different for three-month periods before and after the change. The method of identifying small-volume injections (SVIs) to be manufactured was improved, and SVIs of expensive drugs were prepared every 12, instead of 24, hours; these changes resulted in reduction of one technician full-time equivalent but little change in the percentage or cost of SVIs wasted. Decentralized pharmacists were asked to order certain items on an as-needed basis; this did not affect costs or waste. From 1984 to 1985, total costs associated with waste decreased an estimated $11,000, or 27.5%. This department's attempt to change i.v. admixture procedures based on timely data has resulted in substantial reductions in the cost of waste.

Cost Control↗
PubMed1985

Decision analysis applied to the purchase of frozen premixed intravenous admixtures.

A structured decision-analysis model was used to evaluate frozen premixed cefazolin admixtures. Decision analysis is a process of stating the desired outcome, establishing and weighting evaluation criteria, identifying options for reaching the outcome, evaluating and numerically ranking each option for each criterion, multiplying the ranking by the weight for each criterion, and calculating total points for each option. It was used to compare objectively frozen premixed cefazolin admixtures with batch reconstitution from vials and reconstitution of lyophilized, ready-to-mix containers. In this institution the model numerically demonstrated a distinct preference for the premixed frozen admixture over these other alternatives. A comparison of these results with the total cost impact of each option resulted in a decision to purchase the frozen premixed solution. The advantages of the frozen premixed solution that contributed most to this decision were decreased waste and personnel time. The latter was especially important since it allowed for the reallocation of personnel resources to other potentially cost-reducing clinical functions. Decision analysis proved to be an effective tool for formalizing the process of selecting among various alternatives to reach a desired outcome in this hospital pharmacy.

Cefazolin↗
PubMed1978

Concentration-time profile of phenytoin after admixture with small volumes of intravenous fluids.

A study was designed to determine if admixtures with small volumes of four intravenous fluids (0.45% sodium chloride, 0.9% sodium chloride, 5% dextrose in water and lactated Ringer's) maintain their phenytoin concentrations over a suitable period of time to allow intravenous infusion of the drug. Three phenytoin concentrations (4.6 mg/ml, 9.2 mg/ml and 18.4 mg/ml) were prepared by adding a sufficient volume of an i.v. fluid to the appropriate volume (10.0, 20.0 and 40.0 ml) of phenytoin sodium injection (46 mg of phenytoin acid/ml) to produce a total volume of 100 ml. Each admixture was visually inspected for crystallization, the pH of each solution was determined, and the solutions were filtered through a 0.22-micrometer micropore filter. Unfiltered and filtered aliquots of all solutions were collected at 0, 0.25, 0.5, 1, 4, 8 and 24 hours following admixture. Phenytoin concentrations did not decline systematically during this period nor was there a significant difference (p greater than 0.05) between unfiltered and filtered aliquots in any of the solutions studied, except for the 9.2 mg/ml concentration of 5% dextrose in water. The phenytoin concentrations in the 5% dextrose in water and lactated Ringer's solutions showed the greatest variability over the 24-hour period. The pH for all solutions ranged from 10.15 to 11.50. One-half normal saline and normal saline in small volumes appear to be suitable vehicles for intravenous infusion of phenytoin.

Chromatography, Gas↗
PubMed1984

Antineoplastic admixture service in a tertiary-care hospital.

The rationale and decision-making processes involved in the development and implementation of an antineoplastic admixture service in a 1027-bed teaching hospital are described. Because of concerns expressed by nurses about the potential health hazards of handling antineoplastic drug products, the department of pharmacy was asked to prepare all injectable antineoplastic agents within the institution. At the time of the request, the pharmacy department operated 12 decentralized pharmacies and one central pharmacy; no i.v. admixture services were provided, except for total parenteral nutrient solutions. In developing the service, the pharmacy department considered the advantages and disadvantages of (1) a centralized versus decentralized organization, (2) various physical facilities, and (3) various staffing patterns. An ad hoc committee of the P & T committee was formed to develop multidisciplinary guidelines for the appropriate handling of these products. A centralized service open from 0800 to 1600 daily was established. A supervisor was hired to train and manage the rotation of the entire pharmacy staff through the area. A vertical laminar-airflow biologic safety cabinet and exhaust adapter were purchased, and policies and procedures for handling the antineoplastic agents were developed for all involved personnel. Since opening in July 1983, the antineoplastic admixture service has been positively received by health-care providers in this institution, and no major problems have been associated with the program.

Antineoplastic Agents↗
PubMed1982

Determining a time frame for sterility testing of intravenous admixtures.

Defining an optimal time of analysis for detecting bacterial contaminants in intravenous admixtures was studied. Three different intravenous solutions were inoculated with low-level numbers (10(1)) of Staphylococcus epidermidis and tested for sterility using the Ivex-2 Filterset method at six time intervals after inoculation: less than 1, 20, 40, 60, 120, and 240 minutes. Solutions used were 5% dextrose injection 1000 ml, 0.9% sodium chloride injection 1000 ml, and 5% dextrose injection 50 ml. At each interval, 10 solutions of each type were tested. An additional 20 controls were employed to monitor technique, facilities, and environmental conditions. Successful recovery of Staph. epidermis decreased significantly when sample processing was delayed for longer than 40-60 minutes after inoculation. Furthermore, the number of false negatives was greater for dextrose solutions than for sodium chloride solutions after this time period. Volume of admixtures had no effect on contamination detection. This study suggests that sterility testing should be completed within 40-60 minutes after preparation of intravenous admixtures.

Bacteriological Techniques↗
PubMed1982

Comparison of venous admixture during high-frequency ventilation and conventional ventilation in oleic acid-induced pulmonary edema in dogs.

High-frequency jet ventilation (HFJV) was compared with conventional ventilation ventilation during oleic acid-induced pulmonary edema in dogs. HFJV, when combined with positive end-expiratory pressure (PEEP), returned arterial PO2 (PAO2) and venous admixture to preoleic acid levels, even with tidal volumes as low as 4.8 ml/kg and rates of 300 min-1. When HFJV was compared with conventional (low-frequency, high tidal volume) ventilation at the same Flo2 and level of PEEP, Pao2 was lower and venous admixture higher with HFJV. However, venous admixture was lower with HFJV when comparisons were made at the same peak airway pressure, because of a higher level of PEEP compared with conventional ventilation. At each level of PEEP, cardiac and stroke indices were not different between the two methods of ventilation. The ability to eliminate CO2 with lower peak airway pressures or to increase PEEP without further increases in peak airway pressure are the primary advantages of HFJV during severe lung injury. Oxygenation is as efficient during HFJV as during conventional ventilation in this model of pulmonary edema when comparisons are made at the same peak airway pressure, but less efficient at the same PEEP.

Airway Resistance↗
PubMed1980

Stability of cefazolin sodium admixtures in plastic bags after thawing by microwave radiation.

The effect on antibiotic stability of thawing, with microwave radiation, cefazolin sodium admixtures frozen in polyvinyl chloride minibags was studied. Two brands of cefazolin sodium (Ancef and Kefzol) were reconstituted and placed in 50-, 100- and 250-ml polyvinyl chloride minibags of 5% dextrose in water or 0.9% sodium chloride. The resulting solutions were assayed for antibiotic stability, using an agar disk diffusion technique, and for pH. The solutions were then stored at -20 degrees C for 48 hours, thawed to room temperature in a microwave oven, and kept at room temperature for four hours, after which they were reassayed for potency and pH. The results indicated that after the freeze-thaw process, the cefazolin sodium minibag admixtures retained at least 90% of their initial antimicrobial activity. The minimal pH changes could not be related to changes in antimicrobial activity, and no color changes could be detected visually. Using a microwave oven can greatly reduce thawing time of antibiotic admixtures. To maintain solution stability and prevent accidents, it is important to calibrate the oven, avoid solution overheating, and observe full precautions in oven operation.

Biological Assay↗
PubMed1980

Recommended guidelines for quality assurance in hospital centralized intravenous admixture services. National Coordinating Committee on Large Volume Parenterals.

Guidelines and methods for quality assurance for hospital centralized i.v. admixture services are presented. Objectives to be used to assure quality of i.v. admixture program are recommended and discussion of the guidelines is divided into (1) selection, education, and training of personnel; (2) in-process controls; (3) end-product testing; and (4) sampling guidelines. Cumulative sum procedures are recommended for sampling products prepared in an admixture service.

Centralized Hospital Services↗
PubMed1995

Admixture of a recombinant vaccinia virus containing the gene for the costimulatory molecule B7 and a recombinant vaccinia virus containing a tumor-associated antigen gene results in enhanced specific T-cell responses and antitumor immunity.

At least two signals are required for the activation of naive T cells by antigen-bearing target cells: an antigen-specific signal, delivered through the T-cell receptor, and a costimulatory signal delivered through the T-cell surface molecule CD28 by its natural ligand B7-1. The immunological benefit of coexpression of B7 with target antigen has been demonstrated with the use of several retroviral systems to transfect antigen-bearing cells. Although engineering recombinant constructs with genes for two or more antigens can mediate the dual expression of those antigens, disadvantages of this approach include the time for construction of each desirable combination and the inability to control differential expression levels of each gene product. An alternative approach would utilize separate constructs that could be admixed appropriately before administration. In this report we describe the functional consequences of the admixture of recombinant vaccinia murine B7-1 (rV-B7) to recombinant vaccinia expressing the human carcinoembryonic antigen gene (rV-CEA). Coinfection of cells resulted in high levels of cell surface expression of both the CEA and B7 molecules. Immunization of mice with various ratios (1:3, 1:1, 3:1) of rV-CEA and rV-B7 demonstrated that an admixture of rV-CEA and rV-B7 at a 3:1 ratio resulted in the generation of optimal CEA-specific T-cell responses. Next, we examined the efficacy of this admixture on antitumor activity. Typically, injection of murine carcinoma cells expressing CEA leads to the death of the host. One immunization of C57BL/6 mice with rV-CEA:rV-B7 (3:1) resulted in no tumor establishment. In contrast, administration of rV-CEA or rV-B7 alone had little or no antitumor effects. These studies demonstrate the advantages of the use of recombinant vaccinia viruses to deliver B7 molecules in combination with a tumor-associated antigen. The availability of the rV-B7 single construct and the ability to alter the B7 ratio could also have potential utility when coinfecting rV-B7 with recombinant vaccinia viruses containing genes for infectious agents or other tumor-associated antigen genes.

Animals↗
PubMed1995

Stability study of azlocillin sodium in glass bottles and PVC bags containing intravenous admixtures.

The kinetics of degradation of azlocillin sodium in four intravenous admixtures was investigated at different temperatures. The effect of temperature has been determined and from this data, by applying of Arrhenius-law, the stability of azlocillin sodium at 25 degrees C has been predicted and the t90 was determined. Admixtures containing azlocillin sodium (0.01 g ml-1) were prepared in 0.9% sodium chloride injection, in 5% dextrose solution, in 5% levulose solution and in Ringer's lactate solution. The admixtures were stored at 30 degrees, 40 degrees and 50 degrees C in either polyvinyl chloride bags and glass bottles. The change in the initial azlocillin sodium concentration was related to the type of intravenous solution. No dependence with material of container was found. After 24 hours, the change in the initial concentration of penicillin was less than 10% of the initial concentration in 0.9% sodium chloride and 5% levulose solution. However in Ringer's lactate and 5% glucose solution the t90 was lower. These results were found in agreement with experimental ones obtained at room temperature.

Azlocillin↗
PubMed1993

Stability and compatibility of fluconazole and aminophylline in intravenous admixtures.

The stability of aminophylline and fluconazole in intravenous admixtures containing both drugs was studied. Admixtures containing aminophylline 2.0 or 1.0 mg/mL and fluconazole 1.5 or 0.5 mg/mL in 5% dextrose injection or 0.9% sodium chloride injection were prepared. Each admixture was prepared in triplicate in glass containers and kept at 24 degrees C. Immediately after preparation and at one, two, and three hours, samples were visually inspected, tested for pH, and assayed in duplicate by high-performance liquid chromatography for theophylline concentration and fluconazole concentration. More than 98% of the initial aminophylline and fluconazole concentrations remained at each test interval. There was no visible evidence of precipitation, gas formation, or color change. No appreciable change in pH occurred during the study period. Aminophylline 1.0-2.0 mg/mL and fluconazole 0.5-1.5 mg/mL admixed in 5% dextrose injection or 0.9% sodium chloride injection were stable and compatible for up to three hours at 24 degrees C.

Aminophylline↗