Precision-to-tolerance capability: an important consideration in tight glucose control.

OBJECTIVE: To assess clinical implications of bias and variance of point-of-care glucometric measurements in cardiac surgery patients with wide variations in postoperative hematocrit. METHODS: Point-of-care glucose measurements were compared with values from laboratory analysis of the same sample of whole blood obtained from cardiac patients early on postoperative days 1 and 2. Twenty nurses collected 89 arterial blood samples from 58 patients during a 4-month period. Bias was measured by using difference scores between paired measurements. Patients were grouped within 5% increments according to hematocrit, and analysis of variance was used to test for differences. Variation was analyzed by precision-to-tolerance analysis within 3 euglycemic tolerance ranges. RESULTS: Laboratory glucose values were 62 to 224 mg/dL; point-of-care measures were 83 to 253 mg/dL. Bias was 10.85 mg/dL across all hematocrit groups. Pairs of laboratory and point-of-care glucose values differed significantly (t(174) = 10.03; P < .001). Bias increased from -2.83 mg/dL for patients with hematocrits exceeding 39% to +16.71 mg/dL for patients with hematocrits between 20% and 24%. The standard deviation of difference scores was 11.59 mg/dL overall. The difference between 5% hematocrit groups was significant (F(4) = 4.11; P = .004). Precision-to-tolerance capability ratios for specification limits of 70 to 300, 90 to 140, and 80 to 110 mg/dL were 0.30, 1.39, and 2.32, respectively. CONCLUSIONS: The direction of bias change between hematocrit groupings was the direction predicted in the manufacturer's information. Precision-to-tolerance measures indicated that the point-of-care equipment was not suitable for testing glucose within the planned "tighter" glycemic standards.

Ethical issues surrounding quality improvement activities: a review.

During the past 15 years, issues regarding the ethical conduct of quality improvement activities have emerged. Recently, many have called for regulation of quality improvement studies using institutional review boards. The author reviews the history of the human rights argument within the context of a relevant, newly released study by the Hastings Center and concludes with practical application of the study's findings.

Is dopamine administration possibly a risk factor for delirium?

OBJECTIVE: We explored the possibility that the administration of intravenous dopamine increases the risk for delirium as manifested by need for haloperidol. DESIGN: This study was based on a retrospective analysis. To examine the contribution of dopamine in the prediction of need for haloperidol, a multivariate logistic regression model was used. SETTING: University hospital. PATIENTS: All inpatient admissions to Stanford University Hospital over a 1-year period (n = 21,844). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Dopamine administration was associated with nearly a tripling of the odds of subsequent need of the antipsychotic drug (chi-square = 108, df = 1, p =.0001, odds ratio = 2.89), even after intensive care unit admission and diagnostic related group weight were considered as indicators of severity of illness. Even when analysis was limited to patients seen in the intensive care unit setting (n = 3,308), dopamine administration remained a very strong risk factor for haloperidol and hence possibly for delirium. The increased risk of need for haloperidol in patients administered dopamine is evident in every age group after age 20. CONCLUSIONS: The retrospective nature of this study, the inexact method to assess acuity, and, most of all, the use of haloperidol as an indicator of the presence of delirium preclude concluding that dopamine is directly a risk factor for delirium, much less a causal risk factor. However, the association is potent enough to suggest this possibility strongly and thus supports the need for prospective studies to examine the relationship between dopamine and delirium and to consider possible prophylactic treatment against delirium in those given dopamine.