Development of a new pharmacokinetic model for target-concentration controlled infusion of cefoxitin as a prophylactic antibiotic in colorectal surgical patients.

AIMS: There are several limitations to the existing method of administering cefoxitin as a prophylactic antibiotic, and the limitations may be overcome by applying the target-concentration controlled infusion (TCI) method. Population pharmacokinetic parameters are required to administer cefoxitin by the TCI method. The aim of this study was to construct a new pharmacokinetic model of cefoxitin for the TCI method in colorectal surgical patients. METHODS: In patients undergoing colorectal surgery, 2 g of cefoxitin was dissolved in 50 mL of saline and administered for 10 minutes prior to skin incision. Arterial blood samples were obtained at preset intervals to measure the total and free plasma concentrations of cefoxitin. Population pharmacokinetic analysis was performed using NONMEM software (ICON Development Solutions, Dublin, Ireland). Additionally, stochastic simulation was used to indirectly evaluate the effectiveness of the two administration methods (standard method vs TCI). RESULTS: In total, 297 plasma concentration measurements from 31 patients were used to characterize the pharmacokinetics of cefoxitin. A three-compartment mammillary model described the pharmacokinetics of cefoxitin. Body weight and creatinine clearance were significant covariates for clearance. The stochastic simulation showed that when compared with the standard method, the TCI method has a significantly higher fraction of time that the free concentration of cefoxitin is maintained above the minimum inhibitory concentration (P < .001). CONCLUSIONS: TCI has the potential to become a new infusion method for patient-tailored dosing in surgical patients. To administer cefoxitin via TCI in clinical practice, the newly constructed pharmacokinetic model should undergo proper external validation.

Performance of the MP570T pulse oximeter in volunteers participating in the controlled desaturation study: a comparison of seven probes.

BACKGROUND: The performance of the pulse oximeter was evaluated based on the ISO 80601-2-61:2011 (E) guidelines. This study aimed to determine whether the various finger probes of the MP570T pulse oximeter (MEK-ICS Co., Ltd., Korea) would provide clinically reliable peripheral oxygen saturation (SpO2) readings over a range of 70-100% arterial oxygen saturation (SaO2) during non-motion conditions. METHODS: Each volunteer (n = 12) was connected to a breathing circuit for the administration of a hypoxic gas mixture. For frequent blood sampling, an arterial cannula was placed in a radial artery. The following seven pulse oximeter probes were simultaneously attached to each volunteer's fingers: (1) WA-100 reusable finger probe (MEDNIS Co., Ltd., Korea), (2) MDNA disposable finger probe (MEDNIS Co., Ltd.), (3) IS-1011 disposable finger probe (Insung Medical Co., Ltd., Korea), (4) CJ340NA disposable finger probe (CHUN JI IN Medical Co., Ltd., Korea), (5) NellcorTM OxiMax DS-100A reusable finger probe (Medtronic, USA), (6) NellcorTM OxiMax MAX-N disposable finger probe (Medtronic), and (7) OXI-PRO DA disposable finger probe (Bio-Protech Inc., Korea). RESULTS: A total of 275 SpO2-SaO2 pairs were included in the analysis. The accuracy of the root mean square (Arms ) of each probe was 2.83%, 3.98%, 3.75%, 6.84%, 3.43%, 5.17%, and 3.84%, respectively. CONCLUSIONS: The MP570T pulse oximeter with WA-100 reusable, MDNA disposable, IS-1011 disposable, NellcorTM OxiMax DS-100A reusable, and OXI-PRO DA disposable finger probes meets an acceptable standard of SpO2 accuracy under non-motion conditions.