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Biomedical subjects

C L Ronchera-Oms

Publications and source records attributed to C L Ronchera-Oms.

16 recordsLinked to original sources
PubMed1997

Iopentol (Imagopaque 300) compared with iopromide (Ultravist 300) in abdominal CT. A multi-centre monitoring trial assessing adverse events and diagnostic information--results from 518 patients in Spain.

OBJECTIVES: Iopentol (Nycomed Imaging AS, Oslo, Norway) and iopromide (Schering AG, Berlin, Germany) are low-osmolar, non-ionic, iodinated contrast media (CM) used in abdominal CT examinations. The intravenous safety profile and radiological efficacy of iopentol and iopromide were studied in 518 patients. Specifically, frequency of adverse events (AEs), subjective change in quality of diagnostic information, and quantitative enhancement characteristics were compared. MATERIALS AND METHODS: A prospective, double-blind, randomized, multicentre, parallel-group study was conducted at 8 hospitals. Patients received 100 ml of either iopentol 300 mg I/ml or iopromide 300 mg I/ml. RESULTS: The incidence of patients with AEs was statistically significantly lower in the iopentol group compared to the iopromide group (2.3% vs. 8.9%, p < 0.001). Discomfort was frequent in both groups (44.8% vs. 49.4%, p = 0.33), sensation of heat and warmth being most common. Overall, diagnostic information was similar in both groups. Both CM gave high percentages of examinations rated as optimal (87.1% vs. 90.5%, p = 0.34) and in which diagnostic confidence was increased (87.5% vs. 91.1%, p = 0.22). No significant differences between the two CM were found concerning quantitative enhancement characteristics. CONCLUSIONS: In this study iopentol was significantly safer than iopromide for contrast enhanced CT examination of the abdomen. Radiological efficacy was similar with both CM.

Contrast Media↗
PubMed1996

Differentiation of healthy from cirrhotic livers. Evaluation of parametric images after contrast administration in magnetic resonance imaging.

RATIONALE AND OBJECTIVES: The authors describe a method to differentiate healthy from cirrhotic livers by the analysis of their behavior after paramagnetic contrast administration on magnetic resonance imaging. METHODS: A dynamic single-slice spoiled-gradient recalled echo magnetic resonance imaging after contrast administration was performed on 67 patients (36 healthy livers and 31 cirrhotic livers). Three parametric images (averaged-enhancement, maximum-enhancement, and maximum-velocity) were reconstructed from the temporal dynamic images. Liver values were quantified by means of a region-of-interest procedure. RESULTS: Relative averaged-enhancement and maximum-enhancement values were significantly different ( P < 0.05) between cirrhotic and normal livers. There was a significant correlation between the parametric values and the Child-Turcotte index of hepatic chronic insufficiency (P < 0.05). CONCLUSIONS: Parametric images allow characterization of the signal-versus-time pixel-by-pixel variations in dynamic magnetic resonance imaging. The averaged-enhancement and maximum-enhancement values can be used to differentiate healthy from cirrhotic livers with accuracy. The higher values found in cirrhotic patients may reflect an overall increase in the amount of extracellular contrast present with respect to healthy livers. The degree of liver brightness in cirrhotic patients probably is related to an increased amount of interstitial space, an indirect measurement of hepatic necrosis.

Contrast Media↗
PubMed1995

Randomised double-blind clinical trial of intermediate- versus high-dose chloral hydrate for neuroimaging of children.

Orally administered chloral hydrate is the most widely used sedative in children undergoing MRI. We compared intermediate- and high-dose oral chloral hydrate in 97 consecutive children undergoing MRI in a prospective, controlled, double-blind, randomised clinical trial. There were 50 girls and 47 boys, mean weight (+/- SD) 14.7 +/- 6.4 kg, and mean age 38 +/- 31. The children were randomly allocated to receive chloral hydrate syrup either 70 mg/kg (group A, n = 50) or 100 mg/kg (group B, n = 47). These two groups were not significantly different in sex, weight, age, diagnosis or ambulatory medication. The mean initial dose (+/- SEM) was 64 +/- 2 mg/kg for group A and 93 +/- 2 mg/kg for group B. Because adequate sedation was not achieved, 14 patients in group A and 6 in group B required a second dose, giving a mean total dose of 70 +/- 2 mg/kg for group A and 96 +/- 2 mg/kg for group B. The percentage of successful examinations after the initial dose (A: 64%, B: 87%; p < 0.05) and the total dose (A: 92%, B:100%; p = 0.14) was higher in group B. Significant differences were found for the time of onset of sedation (A:28 +/- 2 min, B: 21 +/- 1 min; p < 0.05), but not for the time to spontaneous awakening after the completion of the examination. The rate of adverse reactions was similar (A: 20%, B: 21%; p = 1.00). We conclude that high-dose oral chloral hydrate improves the management of children undergoing MRI.

Adolescent↗
PubMed1995

Critically-ill patients receiving total parenteral nutrition show altered amikacin pharmacokinetics.

The purpose of this clinical study was to characterise the kinetic behavior of amikacin in the parenterally-fed critically-ill adult patient. 22 critically-ill adult patients treated with amikacin (15.5 +/- 7.9 mg/kg/day) for severe gram-negative infections were enrolled into a non-randomised control trial. Malnourished patients were administered total parenteral nutrition (TPN, n = 11), while well-nourished patients received fluid therapy (FT, n = 11). Amikacin pharmacokinetic parameters were estimated by non-linear regression analysis, assuming a one-compartment model and central first-order elimination. Patients receiving TPN showed an expanded amikacin distribution volume (0.403 +/- 0.0961/kg vs. FT 0.298 +/- 0.083 l/kg, p < 0.05), and a tendency towards increased total body clearance (0.089 +/- 0.029 l/kg/h vs. FT 0.069 +/- 0.0201/kg/h, p = 0.09). TPN produced lower peak concentrations (19.3 +/- 3.1 mcg/ml vs. 23.1 +/- 3.5 mcg/ml, p < 0.05), but had no significant influence on trough concentrations (p = 0.56). Patients on TPN also showed increased body temperature (p < 0.05) and fluid intake (p < 0.05), and decreased hematocrit (p < 0.05). Stress, malnutrition, parenteral nutrition itself, fluid and osmotic overload, and fever often occur concurrently in parenterally-fed patients and appear to produce lower amikacin serum levels. Consequently, critically-ill patients receiving TPN need higher amikacin doses and individualised treatment by monitoring serum concentrations, to ensure optimal therapeutic response.

Journal Article↗
PubMed1995

Stability of parenteral nutrition admixtures containing organic phosphates.

The use of organic phosphates to avoid calcium phosphate precipitation in parenteral nutrition mixtures has been proposed. The purpose of this study was to evaluate the stability of total parenteral nutrition admixtures containing glucose-1-phosphate or glycerol phosphate as the phosphate source over 3 days. Three parenteral nutrition admixtures, each containing glucose-1-phosphate (30.0 mmol), glycerol phosphate (31.4 mmol) or inorganic phosphate (30.0 mmol), and their corresponding aqueous phases were prepared in 3-L ethylene vinyl acetate plastic bags and infusion bottles, and stored at 5 +/- 1 degrees C or 22 +/- 3 degrees C without light protection. Physical stability analysis and sampling for chemical analysis was performed at 0, 24, 48 and 72 h. Aqueous phases were subjected to physical stability analysis, including pH measurement, visual inspection and nephelometry. Admixtures were subjected to physical stability analysis consisting of pH measurement, and evaluation of emulsion stability by visual inspection, degree of creaming, phase contrast microscopy, zone sensing technique and photon correlation spectroscopy. Chemical analyses of amino-acids, dextrose, triglycerides, phospholipids, Na, K, Cl, Mg, Ca, glucose-1-phosphate, glycerolphosphate and inorganic phosphate were performed. No precipitation was detected in any of the aqueous phases. Admixtures remained acceptable with respect to visual and microscopic appearance, mean droplet diameter and droplet size distribution. All nutrient concentrations assayed in the three admixtures remained constant over the study period. Total parenteral nutrition admixtures for adult patients containing glucose-1-phosphate or glycerolphosphate are physically and chemically stable for 3 days when stored under refrigeration or controlled room temperature without light protection.

Journal Article↗
PubMed1995

Assessing the effectiveness of X-ray contrast media for abdominal computed tomographic examinations: comparison of four low-osmolality agents.

The objective of this investigation was to assess the effectiveness of four iodinated X-ray contrast media for abdominal computed tomographic (CT) examinations. Fifty-three patients were prospectively randomized to receive iohexol 300 mgI/ml (100 ml, n = 17), ioversol 320 mgI/ml (100 ml, n = 13), iopromide 300 mgI/ml (75 ml, n = 12), or iopentol 300 mgI/ml (100 ml, n = 11) to perform a dynamic contrast-enhanced abdominal CT. Image-enhancement profiles for the liver, aorta, and vena cava were studied. The maximum liver enhancement, the time to maximum liver enhancement, and the area under the hepatic enhancement-time curve (AUC) were determined for each examination. Liver-enhancement profile showed significant differences between the four contrast agents, with lower values for iopromide towards the final part of the CT examination (P < 0.05). Hepatic peak values were attained earlier for iopromide, although these were lower than those produced by any other of the agents evaluated in this study. Iopentol produced fast and intense hepatic peaks. Consequently, high AUC values were obtained with iopentol, low values were obtained with iopromide (P < 0.05), although this can be explained by the lower amount of contrast medium contained in the commercial vial and administered to the patient (75 ml vs 100 ml). When normalized to a 100 ml dose, the AUC value for iopromide becomes even higher than the average of the other three agents (P = 0.05). Ioversol, although available and administered as a more concentrated solution (320 mg/ml), was comparable to the less concentrated iohexol and iopentol (300 mgI/ml).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Expanded gentamicin volume of distribution in critically ill adult patients receiving total parenteral nutrition.

Aminoglycoside antibiotics distribute into the extracellular fluid compartment and are eliminated by the kidney via glomerular filtration. Malnutrition and total parenteral nutrition influence the fluid and electrolyte status of the patient, and cause organ changes. The purpose of this clinical study was to characterize the kinetic behaviour of gentamicin in the parenterally fed critically ill adult patient. Eighty-six critically ill adult patients treated with gentamicin for severe Gram-negative infections were enrolled in the study (mean +/- SD): age, 60 +/- 14 years; weight, 69.4 +/- 10.2 kg; height, 163 +/- 10 cm; 22 females and 64 males. Four study groups were defined (2 x 2): total parenteral nutrition vs. fluid therapy, and acute renal failure vs. normal renal function. The drug was administered by intermittent intravenous infusion. Blood samples were drawn at steady-state, 5 min before the next dose ('trough') and 30 min after the termination of the infusion ('peak'). Gentamicin serum concentration was determined by fluorescence polarization immunoassay. Gentamicin pharmacokinetic parameters were estimated by non-linear regression analysis, assuming a one-compartment model and first-order elimination from the central compartment. Treatment of malnutrition with total parenteral nutrition increased gentamicin volume of distribution (P < 0.001), but did not affect total body clearance (P = 0.75). This change tended to produce lower peak concentrations (< 4 micrograms/ml, P = 0.07), thus potentially compromising therapeutic effectiveness. There was no significant influence on trough concentrations (P = 0.56). Patients receiving fluid therapy had a volume of distribution of 0.34 +/- 0.08 litre/kg, while those fed by the intravenous route showed larger values (0.43 +/- 0.12 litre/kg), irrespective of their renal function. This may be explained by the extracellular water expansion caused by stress, malnutrition, and parenteral refeeding. Gentamicin dosage regimens in critically ill adult patients on total parenteral nutrition should be formulated on the basis of larger volumes of distribution and to attain therapeutic serum concentrations higher doses may be required.

Adult↗
PubMed1994

Oral chloral hydrate provides effective and safe sedation in paediatric magnetic resonance imaging.

Sedation is routinely required for successful Magnetic Resonance imaging in infants and children. Five hundred and ninety-six paediatric patients (270 female and 326 male, age (mean +/- SD) 41 +/- 30 months and weight 14.8 +/- 6.5 kg) entered an open, non-comparative, prospective study to assess oral chloral hydrate sedation in a large and homogeneous paediatric population undergoing Magnetic Resonance imaging. Chloral hydrate syrup 70 mg/ml was administered 20-40 min prior to the procedure. Effective sedation was reached in 94.1% with a total dose (mean +/- SEM) of 68 +/- 1 mg/kg (range 20-170 mg/kg). Statistical analysis of sedation failures vs. successful examinations after the total dose showed significant differences for dose (62 +/- 4 vs. 69 +/- 1 mg/kg; P < 0.05), age (64 +/- 7 vs. 40 +/- 1 months; P < 0.001) and weight (19.8 +/- 1.5 vs. 14.5 +/- 0.0 kg; P < 0.001). Effectiveness fell to around 80% in children with encephalic white matter alterations, medullary tumours or syringohydromyela (P = 0.07). The mean time of onset of sedation was 26 +/- 1 min, and the mean time to spontaneous awakening after the completion of the Magnetic Resonance examination was 38 +/- 2 min. Fifty-nine children (9.9%) experienced adverse reactions, with nausea and vomiting being the most common (n = 41), followed by nervousness and unusual excitement (n = 6). Discriminant function analysis identified age and total dose as the quantitative variables helping to differentiate between sedation failures and satisfactory examinations (sensitivity = 0.73, and specificity = 0.61; r = 0.20, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

Reduction of peristaltic artifacts on magnetic resonance imaging of the abdomen: a comparative evaluation of three drugs.

BACKGROUND: Peristaltic motion is an omnipresent source of degradation in abdominal magnetic resonance (MR) imaging by blurring images and producing ghost artifacts that can mask or mimic lesions. The objective of this study was to select an effective and easy-to-administer drug to provide consistent reduction of peristaltic motion artifacts on MR images. METHODS: One hundred forty-eight adult patients with MR examinations of the abdomen were enrolled in a prospective, single-blind comparative study. Four groups were defined: (a) no-drug control group (n = 35), (b) 1 mg of intravenous (IV) glucagon (n = 19), (c) 20 mg of IV butylscopolamine (n = 28), and (d) 20 mg of oral dicyclomine (n = 66). All patients received high-density barium sulphate as a negative oral contrast medium. Quantitative image analysis was performed with operator-defined region-of-interest measurements of signal intensity. Gastrointestinal noise was measured outside the patient at the posterior part of the left hemiabdomen along the phase-encoding direction on a short inversion time inversion recovery (STIR) sequence. RESULTS: Treatment groups showed reduced gastrointestinal noise (p < 0.01). When compared with the control group, IV butylscopolamine (p < 0.05) and oral dicyclomine (p < 0.05) significantly reduced gastrointestinal noise, whereas glucagon did not. CONCLUSION: Anticholinergic drugs significantly reduced the intensity of ghost artifacts on MR imaging of the abdomen. Twenty milligrams of oral dicyclomine is an effective and safe alternative to more expensive and parenterally administered drugs such as glucagon and butylscopolamine.

Abdomen↗
PubMedDate not supplied

Dose effect of dicyclomine on the reduction of peristaltic artifacts on MRI of the abdomen.

BACKGROUND: It has been demonstrated that oral administration of dicyclomine significantly reduces the noise associated with the movement of the gastrointestinal tract in abdominal magnetic resonance (MR) images. Our objective was to determine the efficacy and security of two different doses of oral dicyclomine for the reduction of the gastrointestinal noise in abdominal MR imaging. METHODS: Forty-eight patients with MR imaging of the upper abdomen were enrolled in a prospective, controlled, randomized, and double-blind study. All patients ingested barium of high density (196 g in 130 mL of tap water, 250 w/v) approximately 25 min before the MR examination. Patients were randomly distributed into three groups of 16 patients each: (a) no-drug control group, (b) 20 mg of dicyclomine chlorhydrate, and (c) 80 mg of dicyclomine chlorhydrate. Quantitative image analysis was performed with region-of-interest measurements of the signal intensity in background air posterior and lateral to the patient and in the liver. Adverse effects were counted at 2 h and 1 day after the MR examination. RESULTS: The liver and incoherent noise signal intensities were not statistically different among groups. The control group presented a gastrointestinal noise (mean and SD of the air signal intensity) that was statistically superior to that of the groups with dicyclomine (p = 0.004 and p = 0.004, respectively), although significant differences were not observed between the two dicyclomine groups. Although the differences were not significant, adverse effects were more frequently associated with the higher doses of dicyclomine. All the adverse effects (most frequently, constipation, diarrhea, and abdominal pain) were considered minor and did not require treatment. CONCLUSION: Oral dicyclomine is effective and safe for the reduction of peristaltic artifacts on abdominal MR imaging. The dose of 20 mg presents an efficacy similar to that of 80 mg, with a probably lower incidence of adverse reactions.

Abdomen↗
PubMedDate not supplied

[Somatostatin stability in parenteral nutrition units].

The incorporation of somatostatin into parenteral nutritional units has considerable advantages in the treatment of patients subjected to this combined therapy with respect to a reduction in the cost of the therapy and an increase in its effectiveness. This study evaluates the stability of somatostatin in "all-in-one" parenteral nutritional units formulated with or without lipids and preserved at 5 or 25 degrees C for a study period of 7 days. The concentration of somatostatin was determined by high resolution liquid chromatography. All the parenteral nutritional units tested remained stable with regard to content in somatostatin for at least 7 days. The t90 values were around 13.3 days for nutritional mixtures without lipids preserved at 5 degrees C, manifesting the positive influence of refrigeration and lipid emulsion on the stability of somatostatin. None of the PNV showed modifications in pH, colour, precipitation or breakage of lipid emulsion during the study period. The above means that somatostatin can be prepared and administered together with Total Parenteral Nutrition in parenteral nutritional units formulated in the same container.

Drug Stability↗