Transplacental passage of vancomycin from mother to neonate.

OBJECTIVE: The objective of the study was to analyze a large number of patients receiving vancomycin chemoprophylaxis and evaluate the maternal and neonatal cord blood levels at the time of delivery. STUDY DESIGN: Every mother who entered labor with a positive group B streptococcal culture and a high-risk penicillin allergy with resistance to clindamycin or unknown sensitivity was consented to participate in the study. In the initial phase of the study, patients received the standard intravenous dose of 1 g every 12 hours. Based on the results, this was changed to a dosing of 15 mg/kg every 12 hours in the second phase and then further modified to 20 mg/kg every 8 hours in the third phase. Maternal and cord blood vancomycin levels were obtained at delivery and evaluated. RESULTS: A total of 55 patients consented to participate in the study, with 31 in phase I, 12 in phase II, and 12 in phase III. For the standard-dosing phase I group, only 32% of maternal and 9% of cord blood samples were therapeutic at delivery. For phase II, 50% of maternal and 33% of cord blood values were therapeutic; however, in phase III, 83% of mothers and neonates had therapeutic levels at the time of delivery. CONCLUSION: With standard dosing, only 9% of neonates have therapeutic vancomycin levels at delivery. By using a regimen of 20 mg/kg intravenous every 8 hours (maximum individual dose 2 g), the newborn therapeutic level increases above 80%. The pharmacological pattern shows that transplacental passage occurs with fetal levels equaling maternal levels, but transplacental transport is somewhat slow in both directions.

Microvascular effects of subatmospheric pressure in striated muscle.

OBJECTIVE: Topical application of subatmospheric pressure (TASAP) promotes faster wound healing, but tissue effects are not entirely understood. This study investigated microvascular effects of TASAP in striated muscle with the hypothesis being that TASAP elicits arteriolar vasodilation and decreases interstitial accumulation of protein. METHODS: Rat cremasteric microcirculation was directly examined in two experiments utilizing a novel technique. First, TASAP was applied to the cremaster in three experimental groups and a non-TASAP control group. Arteriolar diameters were directly measured before and after TASAP. In experiment two, intravascular fluorescein isothiocyanate (FITC)-labeled albumin and topical leukotriene B4 (LTB4) were delivered to the cremaster. Microvascular permeability was assessed by measuring the accumulation/disappearance of FITC-albumin in the interstitial tissue. RESULTS: TASAP produced significant arteriolar vasodilation compared with control values. The mean maximum percent increase in diameter with TASAP was 8.70% at -2 kPa (p < 0.05), 7.16% at -4 kPa (p < 0.05), and 10.43% at -6 kPa (p < 0.01). TASAP decreased interstitial FITC-albumin by 26.3% (p < 0.008) following LTB4; the control group showed a steady increase in interstitial FITC-albumin. CONCLUSIONS: These results support the hypothesis that TASAP elicits significant arteriolar vasodilation with a subsequent increase in blood flow as well as a decrease in interstitial protein accumulation.