Objective To compare the effectiveness of intermittent and continuous vancomycin infusions in achieving target concentrations in neonates and to assess the implications for clinical practice.
Methods The study involved infants who required treatment with vancomycin during their admission to the neonatal intensive care unit at Yorkhill Hospital, Glasgow, between March and June 2011. During the first month, intermittent vancomycin (Ivanc) infusion was started, at a dose of 10, 15 or 20 mg/kg over 1 h every 12 or 8 h, according to creatinine concentration. Thereafter, doses were adjusted to maintain troughs of 12–15 mg/l.1 Ivanc dosing was maintained in month 2 while staff received training on the continuous vancomycin (Cvanc) infusion guidelines, which comprised of a loading dose of 15 mg/kg followed by a continuous infusion of 20–60 mg/kg/day according to creatinine and corrected gestational age (CGA). Doses were adjusted to maintain concentrations of 15-25 mg/L. These guidelines were implemented in month 3. During months 1 and 4, the following data were collected: age; weight; date, time and dose given; vancomycin concentrations; creatinine concentrations at the start and 2 weeks after therapy. Clinical characteristics were compared by t-test and concentrations by χ2 test.
Results There were 20 courses (15 patients) of Ivanc infusions and 20 (17 patients) of Cvanc infusions. There were no differences in CGA (mean±SD 37.6±4.8 weeks Ivanc versus 38.7±2.7 weeks Cvanc) or weight (2.39±0.95 kg versus 2.66±0.82 kg) between the groups. Mean±SD vancomycin concentrations were 13.3±3.9 mg/l (Ivanc) and 21.7±4.6 mg/l (Cvanc). The first concentration was within the target range in 45% of the Ivanc and 75% of the Cvanc courses. Although similar proportions were above the target ranges (20% and 25% respectively), low concentrations were only observed in the Ivanc group (35%). Overall, 34% of 50 samples were within the target range in the Ivanc group and 77% of 82 in the Cvanc group (p=0.0001; CI95 0.24 to 0.58). The starting dose was correct in 80% of patients in the Ivanc group and 95% in the Cvanc group. In the Ivanc group, 51 doses (18%) were administered >30 min outside the prescribed time; no administration problems were identified in the Cvanc group. In the Ivanc group, eight patients had at least one dose change and two had >3; in the Cvanc group, 10 patients had at least one change and none had >3. Creatinine concentration did not increase in either group.
Conclusions The results suggest that continuous vancomycin infusion in neonates is more likely to maintain concentrations within the target range compared to intermittent vancomycin infusion. In clinical practice, the continuous administration schedule helps to minimise errors with dose times and associated monitoring inaccuracies.