PubMed HealthSearch

Biomedical subjects

T L Rice

Publications and source records attributed to T L Rice.

10 recordsLinked to original sources

Simplified dosing and monitoring of vancomycin for the burn care clinician.

Vancomycin has excellent activity against Gram-positive bacteria and is often selected for use in the infected burn patient. Because of multiple-compartment pharmacokinetics, vancomycin serum concentrations can decrease dramatically in a short time period following the end of an intravenous infusion. This accounts for the widely divergent recommendations for serum vancomycin peak concentrations, e.g. from 15 mg/l up to 80 mg/l, when the time for blood sampling following the end of intravenous infusion is different. It is in general not necessary to monitor vancomycin peak concentrations, not only because its toxic potential is overrated but also because potential toxicity and therapeutic efficacy are correlated with trough concentrations. Post-distribution 'peak' concentrations are generally only useful for determining the optimal dosing interval for patients with impaired renal function. A dosing and monitoring paradigm for vancomycin therapy in burned adults has been devised for burn care clinicians. It provides suggested dose and dosing intervals based on body weight and creatinine clearance, with specific recommendations for regimen modification based upon the results of trough serum concentration determinations.

Adult

Comparison of intravenous and intranasal administration of epinephrine during CPR in a canine model.

STUDY OBJECTIVES: Epinephrine improves coronary perfusion pressure during CPR. However, administration of epinephrine during CPR may be delayed or omitted if IV or endotracheal access is not established. Therefore, the objective of this study was to determine if intranasal administration of epinephrine during CPR would provide an alternate route of drug administration that is readily accessible and requires no special technical skills. DESIGN AND SETTING: Randomized blinded study performed in a controlled laboratory environment. TYPE OF PARTICIPANTS: Twenty mongrel dogs weighing 19.5 +/- 4.6 kg. INTERVENTIONS: All dogs received either IV epinephrine 0.015 mg/kg or intranasal epinephrine 14 mg per nostril. Phentolamine (5 mg per nostril) was administered intranasally one minute before nasal administration of epinephrine to improve absorption. Each dog underwent three minutes of ventricular fibrillation followed by seven minutes of CPR with a pneumatic chest compression device. Epinephrine was administered at two minutes into CPR. MEASUREMENTS AND MAIN RESULTS: Seven dogs were excluded because of inadequate baseline coronary perfusion pressure or compression device displacement, leaving a total of 13 dogs for analysis (six IV epinephrine, seven intranasal epinephrine). Baseline coronary perfusion pressure (mean +/- SD) was similar for IV epinephrine and intranasal epinephrine (16.9 +/- 7.1 mm Hg versus 18.2 +/- 13.8 mm Hg, respectively, P = .84). For IV and intranasal epinephrine, coronary perfusion pressure increased to 21.4 +/- 9.2 mm Hg and 24.4 +/- 18.7 mm Hg one minute after epinephrine, respectively (P = .73). Five minutes after epinephrine coronary perfusion pressure was 18.2 +/- 8.7 mm Hg and 24.3 +/- 13.9 mm Hg for IV epinephrine and intranasal epinephrine, respectively (P = .38). The rate of successful resuscitation was similar for both groups, five of seven dogs for intranasal epinephrine and four of six dogs for IV epinephrine (P = .66). CONCLUSION: Intranasal epinephrine has similar effects on coronary perfusion pressure and resuscitation compared with standard-dose IV epinephrine. Therefore, the nasal route for administration of epinephrine appears to be an acceptable alternate method of drug delivery during CPR and compares favorably with standard IV therapy in the canine model. Because of the obvious benefits to human patients, these observations suggest further investigation.

Administration, Intranasal

Effect of blood and serum on in vitro antibacterial activity of nitrofurazone.

The effect of various volumes of blood and serum on the in vitro antibacterial activity of 0.2% nitrofurazone soluble dressing (NSD) was studied. The antibacterial activity of NSD was tested with an agar well diffusion technique. Zones of inhibition against susceptible strains of Escherichia coli and coagulase-positive Staphylococcus aureus were measured with a micrometer. Bacterial concentrations of 10(5) and 10(8) colony-forming units per milliliter were tested to evaluate a possible effect of inoculum size. Wells contained full-strength (undiluted) NSD or 75%, 50%, or 25% NSD dilutions (w/w) in blood, serum, or 0.9% sodium chloride injection. The mean decrease in inhibition zone size produced by blood and serum was only 7.2%. The diminution of activity, albeit small, was statistically significant. The zones produced were still much larger than those associated with clinical cure. Therefore, the impact of blood and serum on nitrofurazone's in vitro antibacterial activity can best be described as a slight reduction in rather than an elimination of effectiveness. This small reduction in activity is unlikely to be clinically important in patients with burns or other surface wounds that contain blood or serum. An effect of inoculum size was demonstrated for both organisms. Blood and serum produced a small but significant reduction in NSD's antibacterial activity in vitro. Controlled clinical studies are needed to ascertain the clinical importance of these findings.

Blood

Intranasal administration of midazolam to a severely burned child.

This report describes the use of intranasally administered midazolam for sedation in a critically ill burned paediatric patient without venous access. Placement of a central venous catheter was successfully carried out following sedation by this method.

Administration, Intranasal

Influence of rifampin on tocainide pharmacokinetics in humans.

The effects of metabolic enzyme induction by rifampin on the pharmacokinetics of tocainide were studied in eight healthy volunteers. In an open, unrandomized fashion, volunteers received tocainide hydrochloride 600 mg orally. Blood samples were obtained immediately before and at various time intervals up to 48 hours after the dose. Urine samples were collected before and at various intervals up to 72 hours after the dose. Serum and urine samples were assayed for tocainide content by high-performance liquid chromatography. After a four-week washout period, volunteers ingested 300 mg of rifampin by mouth every 12 hours. After 10 doses, subjects received a second oral dose of tocainide hydrochloride 600 mg, and blood and urine samples were collected as before. During the sampling period, subjects continued to ingest rifampin 300 mg orally every 12 hours. Significant differences in elimination rate constant (average increase, 0.0545 to 0.0748 hr-1), elimination half-life (average reduction, 13.2 to 9.4 hours), oral clearance, and area under the concentration-time curve (average reduction, 76.8 to 55.0 mg.hr/L) between the control and rifampin treatment phases were observed. Volume of distribution and renal clearance of tocainide were not significantly different after rifampin treatment. Tocainide appears to be susceptible to significant drug-drug interactions mediated by metabolic enzyme induction.

Adult

Treatment of esophageal varices.

The pathophysiology and treatment of esophageal varices are reviewed. The cause of esophageal varices is generally thought to be portal hypertension. The most common cause of portal hypertension in the United States is alcoholic liver disease. Other etiologies of portal hypertension include portal vein thrombosis, schistosomiasis, and inferior vena caval obstruction by tumor or thrombus. Although short-term balloon tamponade and vasopressin infusion will control acute variceal hemorrhage, they do not affect the underlying problem and are not indicated for long-term treatment of esophageal varices. Surgical procedures either ablate varices or lower portal vein pressure. Portal-systemic shunts have emerged as the preferred surgical technique, but the superiority of total versus selective shunts is unclear. Pharmacological management can include administration of vasopressin, somatostatin, verapamil, or isosorbide dinitrate for short-term treatment or verapamil, isosorbide dinitrate, or propranolol for prolonged treatment. Use of sclerotherapy for treatment and prevention of hemorrhage from esophageal varices has grown recently. Because there are several sclerosing agents and combinations of agents available for use, assessing their relative safety and efficacy is difficult. Innovative approaches to management of varices include a shunt procedure involving the left lung, use of a tissue adhesive, and laser treatment. Because of its effectiveness and ease of administration, sclerotherapy appears to be a rational method of treatment for acute hemorrhage from esophageal varices.

Balloon Occlusion

Leukopenia in acute thermal injury: evidence against topical silver sulfadiazine as the causative agent.

White blood cell data from time of admission to 4 days after burn injury was retrospectively reviewed to determine differences in the incidence of leukopenia in patients with burn injuries treated topically with either silver sulfadiazine or silver nitrate. WBC counts decreased in both groups of patients during the first 3 days after burn injury. An incidence of leukopenia (WBC count less than or equal to 5000/mm3) was observed in of 40 (47.5%) patients treated with silver sulfadiazine and in 13 of 30 (43.3%) patients treated with silver nitrate. There was no statistical difference in the incidence of leukopenia between the two treatment groups. These data suggest that silver sulfadiazine may not be the cause of the leukopenia observed early after burn injury.

Administration, Topical