The role of age in determining the effects of lipo-PGE1 infusion on immediate arterial maximal flow velocity in patients with diabetes undergoing free flap surgery for lower extremity reconstruction: A prospective observational study.

BACKGROUND: Diabetes mellitus may have a negative effect on free flap perfusion in patients undergoing reconstructive surgery. Little is known of the effects of lipo-prostaglandin E1 (lipo-PGE1) on flap blood flow in diabetes. This study investigated the effects of lipo-PGE1 on maximal blood flow velocity of the free flap arterial pedicle in patients with diabetes. METHODS: This prospective observational study assessed maximal blood flow velocity in the arterial pedicle before and 30 min after infusion of 0.4 µg/h lipo-PGE1 in 40 patients with diabetes who received a free flap for lower extremity reconstruction. Multivariate logistic regression analysis was performed to determine whether age, hemoglobin A1c concentration, duration of diabetes, and flap type were significantly associated with increased maximal blood flow velocity after lipo-PGE1 infusion or not. RESULTS: The maximal blood flow velocity of the free flap did not differ significantly before and 30 min after lipo-PGE1 infusion. Multivariate logistic regression analysis showed that age <65 years was the only independent factor associated with increased maximal blood flow velocity after lipo-PGE1 infusion (odds ratio = 5.344; p = 0.022). CONCLUSION: Assessments of all patients with diabetes undergoing free flap surgery, when age was not taken into consideration, found that lipo-PGE1 did not significantly increase the maximal blood flow velocity of the free flap arterial pedicle. However, when age was taken into consideration, lipo-PGE1 increased blood flow velocity in patients <65 years old, suggesting that age influences the effect of lipo-PGE1 on the blood flow velocity.

Population-based volume kinetics of crystalloids and colloids in healthy volunteers.

We characterized the volume kinetics of crystalloid solutions (Ringer's lactate solution and 5% dextrose water) and colloid solutions (6% tetrastarch and 10% pentastarch) by nonlinear mixed-effects modeling in healthy volunteers. We also assessed whether the bioelectrical impedance analysis parameters are significant covariates for volume kinetic parameters. Twelve male volunteers were randomly allocated to four groups, and each group received the four fluid solutions in specified sequences, separated by 1-week intervals to avoid any carryover effects. Volunteers received 40 ml/kg Ringer's lactate solution, 20 ml/kg 5% dextrose water, 1000 ml 6% tetrastarch, and 1000 ml 10% pentastarch over 1 h. Arterial blood samples were collected to measure the hemoglobin concentration at different time points. Bioelectrical impedance spectroscopy (BIS, INBODY S10, InBody CO., LTD, Seoul, Korea) was also carried out at preset time points. In total, 671 hemoglobin-derived plasma dilution data points were used to determine the volume kinetic characteristics of each fluid. The changes in plasma dilution induced by administration of crystalloid and colloid solutions were well-described by the two-volume and one-volume models, respectively. Extracellular water was a significant covariate for the peripheral volume of distribution at baseline in the volume kinetic model of Ringer's lactate solution. When the same amount was administered, the colloid solutions had ~4 times more plasma expansion effect than did the crystalloid solutions. Starches with larger molecular weights maintained the volume expansion effect longer than those with smaller molecular weights.