Relationship between pulmonary oxygen consumption, lung inflammation, and calculated venous admixture in patients with acute lung injury.
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At the root of hygienic standardization of extraneous substances on the ground toxicological experimentation there lies the notion of the noxious action threshold and of the maximum permissible concentration of the substance (MPC). The influence of diverse environmental factors of low intensity on man should not bring forth even temporary disturbances of the homeostasis, including the reproductive function, as well as the strain on defensive and adaptive compensatory mechanisms during the whole of the life span. There arises the need for elaborating indicators that might characterize the "viability" of the organism, or, in other words, the possibility of its performing all the functions that are inherent in a given species. In setting up a biological experiment the maximum attention should be concentrated on integral tests and behavioral reactions that reflect general processes proceeding in the organism, as well as on utilization of "functional loads" that reveal the physiological reliability, on a study of late after-effects at all stages marking the development of the species, but, especially, on bearing in mind the possibility of emerging teratogenic properties. Much study still requires the problem of "indirect" toxic effect of extraneous substances and also of a stringent recording of the food ration for the test animals, which plays an important part in the protection, or, conversely, the debiliation of the organism.
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The stability of procainamide hydrochloride in neutralized 5% dextrose injection was studied. Sixty-four admixtures were prepared by adding either 2 mL (for 0.4% admixtures) or 4 mL (for 0.8% admixtures) of procainamide hydrochloride to 250 mL of 5% dextrose injection in plastic containers. The pH of 32 of these admixtures (16 of each type) was adjusted to 7.5. These 32 admixtures represented the neutralized group, and the remaining 32 represented the control group. The admixtures were stored at either 23-25 degrees C (room temperature) or 5 degrees C (refrigeration) for 24 hours. Procainamide hydrochloride concentrations in each sample were determined by high-performance liquid chromatography immediately after the admixtures were prepared and at various intervals during storage. Procainamide concentrations decreased over time in 5% dextrose injection. The decrease was significantly less for admixtures in neutralized 5% dextrose injection, those stored under refrigeration, and those with an 0.8% concentration of drug. Decreases in procainamide hydrochloride concentrations in the control admixtures might have been caused by procainamide-dextrose complexation. Initial concentrations of procainamide hydrochloride in 5% dextrose injection can be adequately maintained over a 24-hour storage period by neutralizing the 5% dextrose injection or storing the admixture at 5 degrees C. However, because it is impractical to maintain the necessary temperature condition during a 24-hour infusion, neutralization might be the most viable alternative when extended stability of procainamide hydrochloride in 5% dextrose injection is required.
The effect of drug concentration and light on the compatibility and stability of cisplatin and fluorouracil in i.v. admixtures was studied. Two sets of admixtures were prepared in 0.9% sodium chloride injection in polyvinyl chloride bags--(1) cisplatin 200 micrograms/mL and fluorouracil 1,000 micrograms/mL and (2) cisplatin 500 micrograms/mL and fluorouracil 10,000 micrograms/mL. Half of the admixtures were protected from light. All admixtures were stored at room temperature (24-26 degrees C), and those admixtures not protected from light were stored under room fluorescent light. After visual inspection, the pH of each admixture was determined, and an aliquot was assayed for drug concentration using a stability-indicating high-performance liquid chromatographic assay. Over a four-hour period, no visual changes were observed and the pH changes observed were negligible. In admixtures containing the lower concentrations of cisplatin and fluorouracil, it took approximately 1.5 hours for the concentration of cisplatin to reach 90% of the initial concentration. By four hours (lower concentration range) and three hours (higher concentration range) after the admixtures were prepared, less than 75% of the initial cisplatin concentration remained. There was less than a 5% decrease measured in the fluorouracil concentrations over the observation time. Admixtures of cisplatin and fluorouracil in 0.9% sodium chloride injection at the concentrations evaluated in this study must be used within one hour of preparation, whether or not they are protected from light. Intravenous administration of fluorouracil and cisplatin by continuous infusion will require alternative approaches to mixing the two drugs in the same container.
Therapy of chronic respiratory diseases often involves inhalation therapy with nebulizers. Patients often attempt to shorten the time consuming administration procedure by mixing drug solutions/suspensions for simultaneous inhalation. This article considers the issue of physico-chemical compatibility of admixtures of drug solutions/suspensions in nebulizers. A search of databases, prescribing information and primary literature was conducted to locate literature concerning the physico-chemical compatibility of inhalation solutions/suspensions. This was supplemented by telephone interviews. Admixtures of albuterol with ipratropium and/or cromolyn, of albuterol and budesonide, or tobramycin, or colistin are physico-chemically compatible. Physico-chemical compatibility has been demonstrated for admixtures of cromolyn with albuterol and/or ipratropium and for admixtures of cromolyn and budesonide. Admixtures of budesonide with ipratropium and/or fenoterol, and admixtures of budesonide and albuterol, or cromolyn are physico-chemically compatible. Both cromolyn and colistin are incompatible with benzalkonium chloride. Admixtures should be prepared from inhalation solutions/suspensions formulated without preservatives. Besides studies of the physico-chemical compatibility, the aerodynamic behaviour of physico-chemical mixtures needs to be studied before a final recommendation of simultaneous nebulization of compatible admixtures can be made.
The physical compatibility and chemical stability of aztreonam and vancomycin hydrochloride when combined at clinically used high and low concentrations were studied. Admixtures consisting of aztreonam 4 mg/mL and vancomycin 1 mg/mL (as the hydrochloride salt) in 5% dextrose injection, aztreonam 4 mg/mL and vancomycin 1 mg/mL in 0.9% sodium chloride injection, aztreonam 40 mg/mL and vancomycin 10 mg/mL in 5% dextrose injection, and aztreonam 40 mg/mL and vancomycin 10 mg/mL in 0.9% sodium chloride injection were prepared in triplicate in polyvinyl chloride containers. Three containers of each type of admixture were stored at 4, 23, and 32 degrees C. Samples were removed immediately and at various time points over 31 days. Compatibility was assessed by visual examination, with a turbidimeter, and with a particle sizer-counter. Stability was determined by stability-indicating high-performance liquid chromatography (HPLC). All the admixtures initially appeared clear to the unaided eye after the disappearance of a transient white swirl in the high-concentration admixtures (aztreonam 40 mg/mL and vancomycin 10 mg/mL). However, the high-concentration admixtures immediately developed unacceptable levels of a microcrystalline precipitate when viewed with a high-intensity fiber-optic light source. Easily visible gross turbidity and precipitation formed after various periods but often within 24 hours. HPLC showed aztreonam 4 mg/mL and vancomycin 1 mg/mL in 5% dextrose injection to be a stable combination for 7 days at 32 degrees C, 14 days at 23 degrees C, and 31 days at 4 degrees C. In 0.9% sodium chloride injection, the drugs in the low-concentration admixtures were stable for 7 days at 32 degrees C and for 31 days at 4 and 23 degrees C. Stability of the combination in the high-concentration admixtures was maintained for 3 days at 23 and 32 degrees C and for 14 days at 4 degrees C. Aztreonam and vancomycin hydrochloride were considerably less compatible and stable in the high-concentration admixtures than in the low-concentration ones.
OBJECTIVE: To evaluate the interaction of recruitment maneuvers and prone positioning on gas exchange and venous admixture in patients with early extrapulmonary acute respiratory distress syndrome ventilated with high levels of positive end-expiratory pressure. We hypothesized that a sustained inflation performed after 6 hrs of prone positioning would induce sustained improvement in oxygenation (Pao2/Fio2) and venous admixture. DESIGN: Prospective, interventional study. SETTING: Tertiary care, postoperative intensive care unit. PATIENTS: Fifteen patients with early extrapulmonary acute respiratory distress syndrome. INTERVENTIONS: After 6 hrs of prone positioning, a sustained inflation was performed with 50 cm H2O maintained for 30 secs. Data were recorded in supine position, after 6 hrs of prone positioning, at 3, 30, and 180 mins following the sustained inflation. MEASUREMENTS AND MAIN RESULTS: A response to prone positioning was observed in nine of 15 patients leading to an improvement of Pao2/Fio2 (147 +/- 37 torr vs. 225 +/- 77 torr, p = .005) and venous admixture (35.4 +/- 8.3% vs. 28.9 +/- 9.8%, p = .001). Six patients did not respond to prone positioning. Following the sustained inflation, the responders to prone positioning showed a further increase of Pao2/Fio2 and decrease of venous admixture at 3 mins (Pao2/Fio2, 225 +/- 77 torr vs. 368 +/- 90 torr, p = .018; venous admixture, 28.9 +/- 9.8% vs. 18.9 +/- 6.7%, p = .05). In all six nonresponders to prone positioning, an improvement of Pao2/Fio2 and venous admixture occurred at 3 mins following the sustained inflation (128 +/- 18 torr vs. 277 +/- 59 torr, p = .03; venous admixture, 34.2 +/- 6.0% vs. 23.8 +/- 6.3%, p = .05). The beneficial effects of the sustained inflation remained significantly elevated over 3 hrs in responders and nonresponders to prone positioning. CONCLUSION: In patients with early extrapulmonary acute respiratory distress syndrome, a sustained inflation performed after 6 hrs of prone positioning induced further and sustained improvement of oxygenation and venous admixture in both responders and nonresponders to prone positioning.
AIM: To determine malondialdehyde (MDA) concentrations in parenteral nutrition admixtures exposed to ambient room light, and in the serum of neonates. METHODS: Using a new method to measure MDA specifically, this study analysed MDA of lipid-containing all-in-one admixtures provided by the pharmacy, with a composition identical to that used in routine clinical conditions. First, 12 admixtures were exposed to ambient light for 24 h, in the neonatal intensive care unit. Secondly, 18 solutions were either exposed to (n = 9) or protected from ambient light (n = 9) during the same period. Samples of admixtures were collected at baseline and 24 h later, for MDA measurement. Serum MDA was also randomly measured in orally fed healthy neonates. RESULTS: After 24 h exposure to ambient room light, MDA concentrations in parenteral nutrition admixtures increased from 179 (129, 348) nmol l(-1) to 5800 (1632, 14679) nmol l(-1) (p = 0.0002) [50th (10th, 90th) centiles]. When admixtures were protected from light, the increase in MDA was significantly lower than without protection: 187 (60, 429)nmol l(-1) versus 13 696 (3472, 26 049)nmol l(-1) (p = 0.0003). In 54 infants with a gestational age of 33 (28, 39) wk and a birthweight of 1750 (960, 3388) g, plasma MDA concentrations were 173 (98, 315) nmol l(-1). CONCLUSION: In solutions protected from light, MDA concentrations were low and were close to the serum MDA concentrations observed in orally fed neonates. Administration of all-in-one admixtures containing lipids in ambient lighting results in intravenous infusion of high levels of MDA which may present an additional source of morbidity in immature infants. This study confirms the need to protect parenteral admixtures from light.
The chemical and visual stability of amphotericin B in 5% dextrose injection under refrigeration was assessed. Three admixtures of amphotericin B 0.1 mg/mL in 5% dextrose injection and three admixtures of amphotericin B 0.25 mg/mL in 5% dextrose injection were aseptically prepared in polyvinyl chloride (PVC) bags. Immediately after preparation (at time zero), six 5-mL samples were aseptically transferred from each admixture to sterile collection tubes. Three of the samples from each admixture were quick-frozen for later assay by stability-indicating high-performance liquid chromatography (HPLC), and the other three were immediately assessed for pH. Each of the six admixtures was also assessed visually under fluorescent light and 2x magnification for color change, turbidity, gas evolution, and precipitation. The admixtures were stored in PVC bags at 4 degrees C and protected from light. Six 5-mL samples were withdrawn from each admixture at 10, 21, and 35 days. Three of the samples from each admixture were assessed for pH, and three were quick-frozen for subsequent HPLC assay. There was no substantial loss or deterioration of amphotericin B during the 35-day study. At no time was the mean concentration of amphotericin B in the samples less than 96.4% of the concentrations at time zero for the 0.1-mg/mL samples or less than 96.6% of the time zero concentrations for the 0.25-mg/mL samples. There were no appreciable changes in pH, and there was no visual evidence of instability in any of the samples.(ABSTRACT TRUNCATED AT 250 WORDS)
The interlot variability in apparent pH of injectable phenytoin sodium products and the compatibility and stability of phenytoin sodium in admixtures of these products in 0.9% sodium chloride injection were studied. Dilantin (Parke-Davis) and three generic products (Elkins-Sinn, Lyphomed, Solopak) were used. Six lots of each product were diluted to 9.2 and 18.4 mg/mL concentrations. The apparent pH values of undiluted lots and diluted product admixtures were measured. Phenytoin concentrations in the admixtures were measured by turbidimetric immunoassay. Concentration and pH were measured immediately after admixture and at 0.5, 1, and 2 hours; samples were examined for crystallization at each time, and portions were filtered to determine differences in drug concentration between the filtered and unfiltered samples. The Dilantin lots had the lowest interlot variability and significantly higher mean +/- S.D. apparent pH (12.00 +/- 0.06) than the Solopak (11.38 +/- 0.33), Elkins-Sinn (11.39 +/- 0.21), and Lyphomed (11.68 +/- 0.36) products. The apparent admixture pH was significantly higher for Dilantin than for the other products. No crystallization occurred in the Dilantin admixtures; crystallization varied in the other products. Filtration did not significantly alter phenytoin concentrations. No significant differences were detected in phenytoin concentrations between products or sampling times. Interlot variability in pH was lowest for Dilantin, and apparent pH values of the undiluted products and in the admixtures at both drug concentrations were significantly higher for Dilantin than for the other products. Microscopic evidence of physical incompatibility was noted in some generic product lots with lower apparent pH values. Stability of phenytoin in the admixtures over two hours was demonstrated for all four phenytoin sodium injectable products studied.
The nitroglycerin sorptive properties of a polyvinyl chloride i.v. administration set were studied, and the role played by the admixture vehicle in this process was explored. Admixtures of nitroglycerin 0.4 mg/mL were prepared in sterile water for injection, 5% dextrose injection, Ringer's injection, and 0.25%, 0.9%, and 5% sodium chloride injection. Each admixture was divided into two 500-mL sterile glass containers, and flow through the administration set at 100 mL/hr was begun. Samples of effluent were collected at intervals beginning 10 minutes after the start of the infusion and ending at 180 minutes. Nitroglycerin depletion from solution and uptake by the set was determined by an ultraviolet spectrophotometric assay. Initially, the degree of nitroglycerin loss to the set was greatest for dextrose admixtures, intermediate for water admixtures, and least for sodium chloride admixtures. Losses of about 40% were observed during the first 10 minutes; between 15 and 20 minutes, the stated pattern of drug sorption was reversed, with sodium chloride admixtures now showing the greatest loss of nitroglycerin. The availability of nitroglycerin was an inverse function of increasing ionic strength during the three-hour observation period. Nitroglycerin availability in admixtures in contact with a polyvinyl chloride administration set was dependent on the ionic strength of the vehicle and the time points in the infusion period at which measurements were made.
The stability of milrinone and digoxin, furosemide, procainamide hydrochloride, propranolol hydrochloride, quinidine gluconate, or verapamil hydrochloride in 5% dextrose injection containing milrinone was studied. Milrinone admixtures with digoxin, furosemide, propranolol hydrochloride, quinidine gluconate, and verapamil hydrochloride were studied at two concentrations. Admixtures of milrinone and procainamide hydrochloride were studied at four concentrations. Duplicate solutions of each admixture and each control were prepared and stored in glass containers for four hours at room temperature (22-23 degrees C), under normal fluorescent lights. The samples were analyzed immediately by visual inspection, tested for pH, and assayed by high-performance liquid chromatography (HPLC). Milrinone 0.35 mg/mL-furosemide 4 mg/mL and milrinone 0.1 mg/mL-furosemide 5 mg/mL admixtures precipitated immediately after preparation and were not studied by HPLC. No changes in pH or visual appearance were observed in the remaining admixtures after storage at room temperature for four hours. Admixtures containing milrinone 0.175 or 0.2 mg/mL and procainamide hydrochloride 1, 2, or 4 mg/mL satisfied the USP standard for procainamide hydrochloride injection USP assay after one hour but failed this test in all cases after four hours. No degradation of milrinone was observed in any of the admixtures containing procainamide hydrochloride. Milrinone and furosemide are incompatible in 5% dextrose injection and should be administered separately. The remaining admixtures were compatible, and all except those containing procainamide hydrochloride were stable for four hours at room temperature.
Changes in pH values were studied in two types of cardioplegic admixtures containing procaine 0.95 meq/L: an institutional formulation based on Ringer's injection and buffered with tromethamine injection 3.6%, and Plegisol (Abbott Laboratories) buffered with sodium bicarbonate injection 8.4%. Initial pH was measured in the buffered and unbuffered solutions before the addition of procaine and after the addition of 13 mL of procaine hydrochloride injection 2% or 260 mg of procaine hydrochloride powder (reference standard). Buffered 1-L admixtures containing procaine hydrochloride injection were stored (the institutional formulations in glass and the Plegisol admixtures in flexible plastic bags) at 3-5 degrees C or 25 degrees C. Plegisol admixtures were prepared with 10 mL (10 meq or 840 mg) of buffer as directed by the manufacturer or with 3 mL (3 meq) of buffer. Admixture pH was tested after various time intervals. Of the unbuffered solutions containing procaine, pH values were lower in Plegisol than in the institutional formulation. Of the procaine-containing buffered Plegisol solutions, only the admixture containing 3.0 mL of buffer and procaine prepared from powder had an initial pH in the acceptable range of 7.30-7.60. In all the stored solutions, pH changed rapidly; solution pH changed less under refrigeration. In the stored institutional admixtures, pH was acceptable for 96 hours at 3-5 degrees C and 24 hours at 25 degrees C. In the stored Plegisol admixtures to which 10 mL of buffer was added, pH was greater than 7.6 initially and continued to increase.(ABSTRACT TRUNCATED AT 250 WORDS)
The stability of lidocaine hydrochloride in six commonly used large-volume parenterals when stored for 14 days and the visual compatibility of lidocaine hydrochloride in admixtures with eight frequently used drugs were studied. Lidocaine hydrochloride admixtures of 2 mg/ml were prepared in both glass and plastic containers of 5% dextrose injection, 0.9% sodium chloride injection, lactated Ringer's injection, 5% dextrose and lactated Ringer's injection, 0.45% sodium chloride injection (plastic container only), and 0.45% sodium chloride and 5% dextrose injection. The admixtures were examined visually and stored for 14 days at 25 +/- 0.5 degrees C under fluorescent light. Lidocaine hydrochloride concentrations were determined spectrophotometrically at times 0, 0.25, 1, 3, 8, and 24 hours, and at 24-hour intervals thereafter. Spectrophotometric assays were confirmed with high-pressure liquid chromatography. Admixtures of lidocaine hydrochloride were prepared with aminophylline, bretylium tosylate, calcium gluconate, digoxin, dopamine hydrochloride, regular insulin, phenytoin sodium, and procainamide hydrochloride in 5% dextrose injection, 0.9% sodium chloride injection, and lactated Ringer's injection. The admixtures were examined visually for 24 hours. Admixtures of lidocaine hydrochloride were stable for 14 days. All admixtures of lidocaine hydrochloride with other drugs were visually compatible except those containing phenytoin sodium. It is concluded that lidocaine hydrochloride is stable in the solutions studied for 14 days at 25 degrees C and visually compatible for 24 hours in admixtures containing all drugs studied except phenytoin sodium.
The compatibility and stability of netilmicin sulfate in a concentration of 3 mg/ml in 37 intravenous injections and in 5% dextrose and 0.9% sodium chloride injection with 26 commonly used additives were studied. Compatibility between an intravenous administration set and selected admixtures were also evaluated. The admixtures were stored at 4 and 25 degrees C for seven days. After mixing and on days 1, 3, and 7, all admixtures were evaluated for netilmicin potency, pH, color, osmolarity, and clarity. A microbiological assay was used to measure netilmicin potency. No changes in netilmicin potency, pH, osmolarity, color, or clarity were observed in any of the 37 netilmicin sulfate admixtures. Similarly, no changes in pH, osmolarity, or clarity were seen in the admixtures of netilmicin sulfate with a second additive. Netilmicin activity was retained for seven days in 22 of the 26 admixtures with a second additive. Netilmicin sulfate in admixtures with multivitamin injection or vitamin B complex (Upjohn) was stable for only one day; with diphenhydramine hydrochloride or neostigmine methylsulfate, for only three days. No incompatibilities between the intravenous infusion set and admixtures of netilmicin sulfate were apparent. Netilmicin sulfate injection is compatible and stable for at least seven days stored at 4 and 25 degrees C when mixed in 37 intravenous injections, and when mixed individually with 22 additives in 5% dextrose and 0.9% sodium chloride injection.