Objective:To characterize the volatile compounds in 10 batches of disposable infusion sets and 6 batches of nasal can-nulas by GC-MS and determine the main odor-active compounds. Methods:The volatile components were extracted using a headspace sampler. An HP-5MS capillary column (30 m × 0. 25 mm,0. 25 μm) was adopted, and the qualitative analysis was performed by total ion chromatography ( TIC) of full scan with temperature programmer. Results:A total of 19 major volatile compounds were identified, which were hydrocarbon, alcohol and carbonyl compounds (such as aldehyde and ester). Based on the combination of odor test and GC-MS, the concentration of alcohol compounds (2-ethyl hexanol, 2-EH) had the most notable effect on the odor of samples. Conclu-sion:The samples with unacceptable order contain 2-EH with relatively high content, which should be paid more attention.

OBJECTIVETo investigate the effect of vacuum drainage on blood circulation of expanded skin flap, so as to confirm suitable negative pressure for ear reconstruction.

METHODS21 patients (Auricular Reconstructive Center of Plastic Surgery Hospital, PUMC) were randomly divided into A, B, C 3 groups to receive vacuum drainage of: -20, -40 and -60 kPa, respectively. The length and width of reconstructed ears,which represented the swelling degree, were measured instantly and 5, 10 days postoperatively. The changes were calculated and reflected venous drainage of flaps. The temperature of proximal (concha) and distal (helix) part of the expanded flaps, which represented the arterial blood supply of flaps, was detected by infrared thermography after operation.

RESULTSFive days after operation [(1.48 +/- 0.47) mm, (0.36 +/- 0.06) mm] and immediately [(1.67 +/- 0.69) mm, (0.40 +/- 0.16) mm)] , the changes of the length and width of reconstructed ear in group B was significantly low, while there was no statistically difference between group A and C (P > 0.05). The data between 10 days and 5 days after operation showed the same result. Along with the increase of the negative pressure, the swelling degree of reconstructed ears decreased firstly and then increased reversely ( P < 0.01 ). The flap temperature of reconstructed ears increased (P < 0.01), especially in proximal (concha) part (P < 0.01) , when the negative pressure increased (0 to -60 kPa).

CONCLUSIONSVacuum drainage has effect on both the venous drainage and blood supply. Negative pressure of -40 kPa can improve both the blood supply and venous drainage. It should be as reference for clinical application.

Child ; Ear Auricle ; surgery ; Female ; Humans ; Male ; Negative-Pressure Wound Therapy ; methods ; Reconstructive Surgical Procedures ; methods ; Ribs ; transplantation ; Skin Transplantation ; methods ; Surgical Flaps ; blood supply ; Transplantation, Autologous