The effects of dexmedetomidine on human internal mammary artery and saphenous vein grafts under hypothermia and normothermia.

OBJECTIVES: The purpose of this study was to determine the effects of hypothermia and normothermia on the isolated human saphenous vein (SV) and internal mammary artery (IMA) responses to dexmedetomidine. METHODS: The response of human IMA and SV strips with (E+) and without (E-) endothelium subjected to cumulative concentrations of (10-9, 0-6 M) dexmedetomidine were recorded at 37 °C and at 28 °C. OnE-way ANOVA was used for analysis. A p < 0.05 was considered significant. RESULTS: At 37˚C dexmedetomidine resulted in similar significant concentration-dependent contractions in both E+ and E- SV strips (p < 0.05). At 37 °C dexmedetomidine resulted in significant concentration-dependent contractions in E+ IMA strips, these contractions were significantly lower at all concentrations of dexmedetomidine in E- compared to E+ IMA strips (p < 0.05). When results between similar groups of SV and IMA strips were compared, the contractions were significantly higher in the IMA strips in E+ and E- at 37 °C and also E- 28 °C groups compared to SV (p < 0.05). CONCLUSION: In conclusion, dexmedetomidine causes in vitro vasoconstriction in human IMA and SV grafts. These contractions are greater in IMA compared to SV grafts. Endothelium-derived pathways are possibly involved in the contractile responses of IMA. Moderate hypothermia augments vasoconstriction in SV grafts (Fig. 3, Ref. 27).

In vitro vasoactive effects of dexmedetomidine on isolated human umbilical arteries.

OBJECTIVE: We aimed to investigate the vasoactive effects of dexmedetomidine on isolated human umbilical arteries and possible mechanisms involved. METHODS: Human umbilical artery strips were suspended in Krebs-Henseleit solution and dose-response curves were obtained for cumulative dexmedetomidine before and after incubation with different agents; propranolol, atropine, yohimbine, prazosin, indomethacin, verapamil. Effects of calcium on cumulative dexmedetomidine-induced contractions were also studied. RESULTS: Cumulative dexmedetomidine resulted in dose dependent contraction responses. Incubation with propranolol (Emax: 93.3 ± 3.26 %), atropine (Emax: 92.0 ± 6.54 %), or indomethacin (Emax: 94.25 ± 2.62 %), did not attenuate dexmedetomidine-elicited contractions (p > 0.05). There were significant decreases in the contraction responses of cumulative dexmedetomidine with yohimbine (Emax: 12.1 ± 11.9 %), prazosin (Emax: 28.8 ± 4.6 %) and verapamil (Emax: 11.2 ± 13.6 %) (p < 0.05). In Ca+2 free medium contraction responses to cumulative dexmedetomidine was insignificant (Emax: 5.20 ± 3.42 %). Addition of cumulative calcium to the Ca+2 free medium resulted in concentration dependent increase in contractions (Emax: 64.83 ± 37.7 %) (p < 0.05). CONCLUSION: Dexmedetomidine induces vasoconstriction in endothelial-free umbilical arteries via both, α1- and α2-adrenergic receptors and also extracellular Ca+2 concentrations play a major role. ß-adrenergic receptors, muscarinic cholinergic receptors, and inhibition of cyclooxygenase enzyme are not involved in this vasoconstriction (Fig. 3, Ref. 36).

The relationship between teamwork attitudes and caring behaviors among nurses working in surgical clinics: A correlational descriptive study.

AIM: This study was planned and carried out to determine how teamwork attitudes of nurses working in surgical clinics affect their caring behaviors. MATERIALS AND METHODS: The research was conducted as a relational descriptive study. The research population consisted of 126 nurses working in the surgical clinics of a state hospital. A total of 116 nurses who agreed to participate in the study were admitted to the study. Data were collected using the Descriptive Characteristics Question Form, the Teamwork Attitudes Questionnaire (TAQ), and the Caring Behaviors Inventory-24 (CBI-24). Data were analyzed using counts, percentage distributions, Mann-Whitney U test, and Kruskal-Wallis tests, Games-Howell post hoc test, and Spearman's correlation. RESULTS: The nurses participating in the study were found to have a mean score of 112.11 ± 17.86 for the TAQ and a mean score of 4.95 ± 0.54 for the CBI. There was a statistically positive correlation between the nurses' teamwork attitudes and caring behaviors (P < 0.05). CONCLUSION: It can be said that the teamwork attitudes of the nurses had a positive effect on their caring behaviors. It may be suggested to plan relevant research studies examining especially observational behavioral assessments.