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Biomedical subjects

S M Watling

Publications and source records attributed to S M Watling.

10 recordsLinked to original sources
PubMed1995

In vitro binding of lithium using the cation exchange resin sodium polystyrene sulfonate.

Sodium polystyrene sulfonate, a cation exchange resin, should be useful in the treatment of lithium overdosage. This in vitro study was conducted to assess the ability of sodium polystyrene sulfonate to bind lithium, effects of pH on binding, binding efficacy in comparison to charcoal, and affinity for lithium versus potassium. Stock solutions of lithium were added to fixed amounts of sodium polystyrene sulfonate and charcoal. Lithium and potassium concentrations in supernatant were measured by flame photometry. Increasing concentrations of sodium polystyrene sulfonate bound more lithium. Changes in pH had little effect on lithium binding. Lithium is bound to sodium polystyrene sulfonate more readily than to charcoal. Potassium is preferentially bound to sodium polystyrene sulfonate over lithium. Sodium polystyrene sulfonate may provide a useful therapeutic modality in the treatment of lithium overdosage.

Binding Sites↗
PubMed1995

Nursing-based protocol for treatment of alcohol withdrawal in the intensive care unit.

Inappropriate benzodiazepine dosing in patients exhibiting signs of alcohol withdrawal cause staff and patient safety problems. Our primary goal was to develop an alcohol withdrawal protocol based on objective measures, and then to coordinate benzodiazepine dosing with those measures and improve care of the patient withdrawing from alcohol. A secondary goal was to give the primary care nurse the flexibility to administer benzodiazepine doses as needed to improve patient and staff safety. We developed and implemented a modified version of a published withdrawal symptomatology scale; a corresponding scale was developed for benzodiazepine dosing by observing the usual lorazepam doses needed to control withdrawal symptoms. Both scales and care guidelines for the patient withdrawing from alcohol were organized in the form of preprinted orders. Since implementation of the alcohol withdrawal protocol, complaints regarding patient and staff safety have decreased. Other patient care units are beginning to use the protocol. A hospital-wide task force is developing patient care plans based on the protocol for all patients withdrawing from alcohol.

Alcohol Withdrawal Delirium↗
PubMed1994

Prolonged paralysis in intensive care unit patients after the use of neuromuscular blocking agents: a review of the literature.

OBJECTIVES: To review the reports of prolonged neuromuscular blockade secondary to vecuronium and atracurium administration. To propose mechanisms for prolonged blockade, as well as methods to avoid prolonged blockade. DATA SOURCES: A literature search was conducted of articles published from 1980 to 1993. Articles pertaining to pharmacokinetic and pharmacodynamic alterations, prolonged neuromuscular blockade, and continuous infusion administration of vecuronium and atracurium were obtained. STUDY SELECTION: Studies and case reports pertaining to prolonged neuromuscular blockade in intensive care unit patients were reviewed and summarized. DATA EXTRACTION: All articles were reviewed by both authors. Primarily, the critical care literature and anesthesia literature were reviewed. Case reports were divided into two groups, based on end-organ function and possible cause. DATA SYNTHESIS: Prolonged neuromuscular blockade can be divided into two types. One is pharmacokinetically based, due to alterations in clearance and metabolite formation. The second occurs in patients without an etiology for drug clearance problems. Functional neuromuscular junction defects are the problem and may be due to the underlying disease state in addition to, or regardless of, the use of neuromuscular blocking agents. CONCLUSIONS: Controlled studies assessing the appropriate drug, administration method, use of drug in end-organ dysfunction, and monitoring techniques are unavailable. From the available case reports, length of neuromuscular blockade has been associated with end-organ dysfunction, concomitant drug use, severity of the underlying illness, length of therapy, monitoring techniques used, and perhaps method of drug administration. Steroidally based neuromuscular blocking agents may be particularly hazardous in patients receiving systemic corticosteroids. It is premature to determine the safety of one particular neuromuscular blocking drug in relation to another. Further studies are needed to optimize the use and safety of neuromuscular blocking agents in intensive care unit patients.

Adrenal Cortex Hormones↗
PubMed1992

Verapamil overdose: case report and review of the literature.

OBJECTIVE: To report the presentation and controversies regarding therapy of an 18-year-old man following a life-threatening ingestion of verapamil. CASE SUMMARY: An 18-year-old man ingested large quantities of dipyridamole, trimethoprim/sulfamethoxazole, amoxicillin, and verapamil. He presented to an outlying hospital and was initially conscious. Soon thereafter, the patient had a seizure; he required intubation, developed cardiac conduction abnormalities, and became hypotensive. The patient required pharmacologic pressors and a pacemaker for transfer to our institution. At our institution, vigorous fluid resuscitation, cardiac pacing, and careful attention to acid/base and electrolyte management provided the basis of therapy. The patient recovered without deficit and was discharged from the intensive care unit five days later. DISCUSSION: Current controversies regarding the management of verapamil overdose are reviewed. Removal of the drug by gastric lavage is a mainstay of therapy. Administration of syrup of ipecac is contraindicated. Although specific recommendations for calcium dosing in the overdose situation have not been rigorously studied, maintenance of a normal serum ionized calcium concentration is suggested. An exogenous catecholamine, rather than dopamine, may be the drug of choice for treating hypotension. Cardiopulmonary bypass provides a method for drug removal in cases of severe toxicity; however, this invasive method requires further study. Management of fluid/electrolyte, acid/base, and ventilation abnormalities is required to treat large ingestions of verapamil. Treatment guidelines for critical care clinicians are provided.

Adolescent↗
PubMed1992

Population pharmacokinetics of gentamicin. Use of the nonparametric expectation maximisation (NPEM) algorithm.

A new nonparametric expectation maximisation (NPEM) algorithm for the estimation of population pharmacokinetic parameter values was evaluated. The algorithm, in the form of a personal computer program, was used to compute population pharmacokinetic parameter densities of gentamicin in a group of 9 patients with indicators of malnutrition. The 1-compartment parameter values for clearance (CL), volume of distribution (Vd) and elimination rate constant (k) were compared with values generated using a standard 2-stage (STS) approach. NPEM was used with a full data set (72 gentamicin concentrations) and a sparse data set (only peak and trough concentrations for each patient; 18 in total). There were no differences in parameter value estimations between the STS and NPEM with all the data (p greater than 0.05) or with the sparse data (p greater than 0.05). Mean parameter value estimates from the STS and NPEM (with sparse data) were used as a priori data sets in the USC*PACK gentamicin Bayesian program to predict concentrations in 8 subsequent patients with similar indicators of malnutrition. There were no differences in predicted gentamicin concentrations between STS (3.75 +/- 2.06 mg/L) and NPEM (3.75 +/- 2.17 mg/L). NPEM was able to generate population pharmacokinetic parameter values for gentamicin in a defined population of patients using sparse routine clinical data. It was also shown to function with only a single data point per patient.

Aged↗
PubMed1991

The impact of changing ventilator parameters on availability of nebulized drugs in an in vitro neonatal lung system.

An in vitro model was developed to assess nebulized drug delivery. The model simulated the intubated neonate and examined the effect of changes in a variety of parameters commonly confronted in the clinical setting. Theophylline was nebulized for 15 minutes and captured in an artificial lung system (a 1000-mL intravenous bag). Variables were: peak pressure (20, 24, 28 cm H2O), ventilator rate (40, 60, 80 breaths/min), nebulizer flow rate (5, 7, 10 L/min), endotracheal tube size (2.5, 3.0, 3.5 mm), and ventilator type (Servo 900C, Bourns BP 200, Bear Cub BP 2001). The amount of drug actually captured in the bag ranged from 0.009 to 12.59 percent (mean 2.08). A multivariate analysis showed that only nebulizer flow rate had a statistically significant effect on drug delivery with 10 L/min delivering the most drug. All factors combined only accounted for 11.5 percent of the variability in drug delivery. In light of the wide and unpredictable amounts of drug delivered through ventilators, dosing to pharmacologic effect rather than staying within narrow dosing guidelines may be more rational in patients responding poorly to standard doses.

Humans↗