Predictors of intraoperative testing in adults undergoing noncardiac surgery within a regional hospital system.

BACKGROUND: The use of intraoperative testing is central to anesthesia practice, and point-of-care testing (POCT) is often used. Nevertheless, POCT is costly and its contribution to patient outcome is unknown. There is a lack of guidelines to describe which patients should undergo intraoperative testing or how results should be applied. As such, we undertook a historical cohort study evaluating intraoperative testing practices within our region where POCT is not used. METHODS: In 2012, we obtained a random sample of 1,000 adult patients undergoing noncardiac surgery in three of our health system hospitals. Patient, surgical, and testing details were extracted, and the surgical procedures were categorized using the Johns Hopkins risk guidelines. Our primary outcome was the administration of at least one intraoperative test. We used a multivariable logistic regression model to identify factors associated with testing and described the time from ordering the tests to receiving the results using descriptive statistics. RESULTS: Study results showed that 110/1,000 (11.0%) patients underwent 413 diagnostic tests. Complete blood count was the most commonly administered test (36.3%), and the mean (standard deviation) time to obtain all test results was 29.9 (19.9) min. High-risk procedures were associated with an odds ratio (OR) of 12.3 (95% confidence interval [CI], 8.3 to 18.2; P < 0.001). Other predictors of intraoperative testing included emergency surgery (OR, 3.8; 95% CI, 2.0 to 7.2; P < 0.001), number of comorbidities (OR, 1.1; 95% CI, 1.0 to 1.2; P = 0.03), and duration of surgery (OR, 2.3; 95% CI, 1.8 to 2.9; P < 0.001). CONCLUSION: Intraoperative testing is common and more likely in patients undergoing high-risk surgical procedures. In a central laboratory system, there is substantial time from ordering the tests to receiving the results. The clinical impact of this delay is unknown. Further evaluation is required regarding the relationship between the time required for intraoperative test results and perioperative outcomes.

Intravenous fluorescein angiography-associated adverse reactions.

OBJECTIVES: To assess (i) the adverse reactions (ARs) associated with intravenous fluorescein angiography (IVFA); (ii) the relationship between a known history of IVFA-associated AR and ARs on the subsequent IVFA test; and (iii) the dose-response relationship between intravenous sodium fluorescein (NaFl) injection and ARs associated with IVFA. DESIGN: Retrospective chart review. PARTICIPANTS: A total of 2247 patients with 3381 consecutive IVFAs between May 2013 and April 2014. METHODS: Fisher's exact tests or χ2 tests were used to compare the percentage difference of IVFA-associated ARs for different categorical variables. Logistic regressions were used to assess the relationship between a known history of IVFA-associated AR and any AR(s) on a subsequent IVFA test. RESULTS: The overall percentage for IVFA-associated ARs was 3.3%. Adjusted for age and sex, patients who had a previous IVFA-associated AR(s) were 6.2 times more likely (adjusted odds ratio 95% CI 3.4-11.2, p < 0.0001) to have an AR compared to those who did not. Among 17 patients who had 2 repeated IVFA tests and an AR on the first IVFA test, the rate of AR on the second test was lower in patients who received a reduced dosage of NaFl (n = 14) compared to those with the standard dosage (n = 3) (35.7% vs 66.7%); however, this finding was not statistically significant (p = 0.5368). CONCLUSIONS: The rate of IVFA-associated ARs in this study was low. Patients who had a known IVFA-associated AR were more likely to re-experience an AR on a subsequent test compared to those who did not. In addition, a reduced NaFl dose did not significantly reduce the chance of experiencing an AR on a subsequent test, which is likely because of the insufficient power of this comparison.

Optimized tetramer analysis reveals Ly49 promiscuity for MHC ligands.

Murine Ly49 receptors, which are expressed mainly on NK and NKT cells, interact with MHC class I (MHC-I) molecules with varying specificity. Differing reports of Ly49/MHC binding affinities may be affected by multiple factors, including cis versus trans competition and species origin of the MHC-I L chain (ß2-microglobulin). To determine the contribution of each of these factors, Ly49G, Ly49I, Ly49O, Ly49V, and Ly49Q receptors from the 129 mouse strain were expressed individually on human 293T cells or the mouse cell lines MHC-I-deficient C1498, H-2(b)-expressing MC57G, and H-2(k)-expressing L929. The capacity to bind to H-2D(b)- and H-2K(b)-soluble MHC-I tetramers containing either human or murine ß2-microglobulin L chains was tested for all five Ly49 receptors in all four cell lines. We found that most of these five inhibitory Ly49 receptors show binding for one or both self-MHC-I molecules in soluble tetramer binding assays when three conditions are fulfilled: 1) lack of competing cis interactions, 2) tetramer L chain is of mouse origin, and 3) Ly49 is expressed in mouse and not human cell lines. Furthermore, Ly49Q, the single known MHC-I receptor on plasmacytoid dendritic cells, was shown to bind H-2D(b) in addition to H-2K(b) when the above conditions were met, suggesting that Ly49Q functions as a pan-MHC-Ia receptor on plasmacytoid dendritic cells. In this study, we have optimized the parameters for soluble tetramer binding analyses to enhance future Ly49 ligand identification and to better evaluate specific contributions by different Ly49/MHC-I pairs to NK cell education and function.