Pierre Cardinal

A pilot study using high-fidelity simulation to formally evaluate performance in the resuscitation of critically ill patients: The University of Ottawa Critical Care Medicine, High-Fidelity Simulation, and Crisis Resource Management I Study.

Objective:Resuscitation of critically ill patients requires medical knowledge, clinical skills, and nonmedical skills, or crisis resource management (CRM) skills. There is currently no gold standard for evaluation of CRM performance. The primary objective was to examine the use of high-fidelity simulation as a medium to evaluate CRM performance. Since no gold standard for measuring performance exists, the secondary objective was the validation of a measuring instrument for CRM performance—the Ottawa Crisis Resource Management Global Rating Scale (or Ottawa GRS). Design:First- and third-year residents participated in two simulator scenarios, recreating emergencies seen in acute care settings. Three raters then evaluated resident performance using edited video recordings of simulator performance. Setting:A Canadian university tertiary hospital. Interventions:The Ottawa GRS was used, which provides a 7-point Likert scale for performance in five categories of CRM and an overall performance score. Measurements and Main Results:Construct validity was measured on the basis of content validity, response process, internal structure, and response to other variables. One variable measured in this study was the level of training. A t-test analysis of Ottawa GRS scores was conducted to examine response to the variable of level of training. Intraclass correlation coefficient scores were used to measure interrater reliability for both scenarios. Thirty-two first-year and 28 third-year residents participated in the study. Third-year residents produced higher mean scores for overall CRM performance than first-year residents (p < .0001) and in all individual categories within the Ottawa GRS (p = .0019 to p < .0001). This difference was noted for both scenarios and for each individual rater (p = .0061 to p < .0001). No statistically significant difference in resident scores was observed between scenarios. Intraclass correlation coefficient scores of .59 and .61 were obtained for scenarios 1 and 2, respectively. Conclusions:Data obtained using the Ottawa GRS in measuring CRM performance during high-fidelity simulation scenarios support evidence of construct validity. Data also indicate the presence of acceptable interrater reliability when using the Ottawa GRS.

Functional magnesium deficiency in critically ill patients identified using a magnesium-loading test.

OBJECTIVEnTo determine the feasibility of the magnesium-loading test in the critically ill and to validate serum ionized magnesium assay using the magnesium-loading test as a reference in this same patient population.nnnDESIGNnDouble-blind, randomized, controlled clinical investigation.nnnSETTINGnTertiary level intensive care unit.nnnPATIENTSnForty-four consecutive critically ill patients without evidence of renal insufficiency.nnnINTERVENTIONnPatients were randomly allocated to receive 30 mmol (7.5 g) of magnesium sulfate daily for 3 days, or an equivalent amount of normal saline.nnnMEASUREMENTS AND MAIN RESULTSnWe recorded baseline characteristics, and serial serum biochemical measurements included creatinine, glucose, sodium, potassium, phosphate, total calcium, ionized calcium, total magnesium, and ionized magnesium. Serum assays were accompanied by 24-hr urine collections of creatinine and magnesium over the 3-day period. Baseline characteristics were comparable in both groups. In patients receiving magnesium, serum ionized magnesium and total magnesium concentrations were increased by 43% (p = .0001) and 59% (p = .0002), respectively, on day 1 as compared with the control group. Magnesium excretion in the control group averaged 4.8 +/- 2.3 mmol/day during the 3-day study period, while the magnesium excretion in the magnesium-loaded group was significantly increased to 22.7 +/- 10.9 mmol/day (p < .0001). Following day 1 magnesium loading, patients who excreted < 70% of the total magnesium (30 mmol infused magnesium plus 4.8 mmol basal excretion) were termed as functionally magnesium-deficient retainers (n = 12), and patients who excreted > 70% of the total magnesium were termed as nonretainers (n = 7). In addition, magnesium retainers on day 2 (nine of ten patients) and day 3 (five of six patients) excreted > 70% of the total magnesium, indicating a replenishment of body magnesium stores. In contrast, nonretainers on day 2 (four of five patients), and day 3 (four of four patients) continued to excrete excess amounts of magnesium. In the retainer group, only two patients had a low serum ionized magnesium concentration, while two other patients had low total serum magnesium values. In addition, magnesium retention was associated with low ionized calcium and high phosphate values.nnnCONCLUSIONSnThe magnesium-loading test is feasible and appears to be valid based on its performance during the 3-day evaluation. Using the magnesium-loading test as a reference, serum ionized magnesium appears to be an insensitive biochemical marker of functional hypomagnesemia. Larger cohort studies using the magnesium-loading test will help establish the true prevalence of magnesium deficiency and its associated risk factors in critically ill patients.

A comparison of global rating scale and checklist scores in the validation of an evaluation tool to assess performance in the resuscitation of critically ill patients during simulated emergencies (abbreviated as "CRM simulator study IB").

Background: Crisis resource management (CRM) skills are a set of nonmedical skills required to manage medical emergencies. There is currently no gold standard for evaluation of CRM performance. A prior study examined the use of a global rating scale (GRS) to evaluate CRM performance. This current study compared the use of a GRS and a checklist as formal rating instruments to evaluate CRM performance during simulated emergencies. Methods: First-year and third-year residents participated in two simulator scenarios each. Three raters then evaluated resident performance in CRM using edited video recordings using both a GRS and a checklist. The Ottawa GRS provides a seven-point anchored ordinal scale for performance in five categories of CRM, and an overall performance score. The Ottawa CRM checklist provides 12 items in the five categories of CRM, with a maximum cumulative score of 30 points. Construct validity was measured on the basis of content validity, response process, internal structure, and response to other variables. T-test analysis of Ottawa GRS scores was conducted to examine response to the variable of level of training. Intraclass correlation coefficient (ICC) scores were used to measure inter-rater reliability for both scenarios. Results: Thirty-two first-year and 28 third-year residents participated in the study. Third-year residents produced higher mean scores for overall CRM performance than first-year residents (P < 0.05), and in all individual categories within the Ottawa GRS (P < 0.05) and the Ottawa CRM checklist (P < 0.05). This difference was noted for both scenarios and for each individual rater (P < 0.05). No statistically significant difference in resident scores was observed between scenarios for both instruments. ICC scores of 0.59 and 0.61 were obtained for Scenarios 1 and 2 with the Ottawa GRS, whereas ICC scores of 0.63 and 0.55 were obtained with the Ottawa CRM checklist. Users indicated a strong preference for the Ottawa GRS given ease of scoring, presence of an overall score, and the potential for formative evaluation. Conclusion: Construct validity seems to be present when using both the Ottawa GRS and CRM checklist to evaluate CRM performance during simulated emergencies. Data also indicate the presence of moderate inter-rater reliability when using both the Ottawa GRS and CRM checklist.

Artifactual elevation of lactate in ethylene glycol poisoning.

The diagnosis of ethylene glycol poisoning is based on nonspecific clinical symptoms and signs and indirect and direct laboratory measurement. Few institutions have timely access to direct measurement of ethylene glycol. As a result, diagnosis sometimes can be delayed and therapy initiated late. We present two cases of ethylene glycol poisoning. These cases demonstrate the need to recognize the false elevation of lactate in some chemistry analyzers due to the interference of glycolic acid, a metabolite of ethylene glycol. Using the lactate gap in comparing the measurement of lactate with two commonly used chemical analyzers aids in differentiating ethylene glycol poisoning from lactic acidosis.