Jpn. J. Infect. Dis., 53, 2000

Laboratory and Epidemiology Communications

Monitorlng for Airbome Particles durlng and after SurglCal
Operations on Tuberculosis Patients
Kiminori Toyooka, Hiroichi Kishi, Yoshikazu Naiki, Etsuko Hino, Toshiko Suzuki,
Morito Sumlya, Koichiro Kudo, Oichirou Kobori, Yoshio Yazaki and Teruo Kirikae*International Medical Center ofJapan,
Toyama 1‑21‑1, Shinjuku‑ku, Too,0 16218655
Communicated by Hiroshi Yoshikura(Accepted October 23, 2000)

Ventilation control is essential for preventlng nOSOCOmial
transmiesion ofairbome infections, such as tuberculosis (1 )･

ventilation system in the operating rooms and suggested that

A practlCal method to assess ventilation systems in health‑care facilities involves monitorlngairbome particles of aremoved contaminated air.

certain rang.e in. size using particle counters (2)･

followlng OPerations, We monitored airborne particles after

the short‑term ventilation followlng the operation effectively

To assess the emcacy of operating room ventilation
two operations each in two operatlng rOOmS･ In ORl , it took

The monltOrlng Was COnducted in operating rooms (ORland OR8) in a hospital with 925 beds befわre, during, andabout 15 and 16 min, respectively, for the airbome particles

after operations on patients who had tuberculosis･ The ORlto decrease to仇e backgrounds levels (Fig. 2 A, B)･ In OR8,andOR8 were of the same size: 91.8 m3 (6 mwide by 6 m

it took 36 and 18 min (Fig. 2 C, D). These data indicate thatdeep by 2.55 m high). TYle OR8 had an anteroom of38125 m3

monitorlng f♭r airbome particles during and a触r surglCal(5 m wide by 3 m deep by 2.55 m high). Bo仇operating rooms

were equlPPed with the same slngle‑pass ventilation system

OR l【Jun.9】

in which, a洗er alr passes through the room, 100% of that air

was exhausted to the outside. Two air‑supply vents wereU :1 0 :1 ♂ :1 ♂ 1 03 1

located in the ceiling and four air‑exhaust vents were near

the moor in each comer. The vents were fitted with high‑I 鳴ﾂﾂﾂlefficiency particulate air (HEPA) filters for air cleaning･ The≧0.3 pm

air supplyand exhaust volumes were 1 ,357and 1 ,537 m3瓜forORl, 2,079 and 2,829 m3nl for OR8,and 576 and I,323 m3nl
for the anteroom of OR8, respectively. Airbome particles withL.J.‑I■■≧0.3, ≧0.5, ≧1.0, ≧2.0, and ≧5.0 LLm diameter in ORland OR8 Were simultaneously counted using a laser particle≧ 0.5 1〝ncounter (KC‑03Al, 及ion Co., Tbkyo) placed on a stand 1 min height, 50 cm from the wall, 50 cm leftfrom an exhaustcf＼∽OP!Uedvent that was on the side of the corridor but opposite the door.

The nuctuation in airbome particles in an operatlng room

Iis shown in Figure 1. The ventilator was tuned on at 7:20 inIthe momlng. Two nurses entered and left the room from 8:30

≧1 llmto 9:00 for preparation. The entrance time of a patient withthree doctors and two nurses was 9:00, and the leavlng time

血■一was 15:31. After leavlng, nO One Was allowed to enter theroom until the end of the monitoring period. Before the ven‑I

tilator was tuned on, littlefluctuation in numbers of particles

友≧2llmwas observed. Particles of ≧0.3 and ≧0.5 Elm diameter

were2‑6 × 103/ft3(7‑20× 104/m3)and216 × 102/ft3(7‑20 X 103/m3), respectively, and larger particles were few.

胡After the ventilator was turned on, the numbers of small

鳴A..
l :I .鳴lparticles immediately decreased. When the patient entered,numbers of particlesincreased and remained high with sharp≧5llm

fluctuations, i.e., 102‑ 103/ft3 for ≧0.3 LLm, 10 ‑ 103/ft3 for≧0.5 LLm and ≧1 LLm, during the operation. After the6:00

patient left, the number of particles decreased rapidly by a9:00

1 2:00

15:00

Timefactor of 102/ft3 for ≧0.3 LLm, 10/ft3 for ≧0.5 LLm, and <10/ft3 for ≧ 1 LLm. These data confined the efficacy of theFig. I. Monitonng of airborne particles before, during, and after asurgical operation in an operating room (ORl )･ Number ofairbome'Corres.ponding author: Fax: +8 1 ‑3‑3202‑7364, E‑mail: tkirikae@

particles (average orcounts fわr 1 min) of≧0.3, ≧0･5, ≧1･0, ≧2･0,ri.imq.goJPand ≧ 5.0 LLm diameters are plotted inthe verticalaxis.

206

Jpn. J. Infect. Dis., 53, 2000

A15:31 15:46

16:05 16:21

15:52

16:28

16:30

16:48

TimeFig･ 2･ Monitonng ofairbome particles of >1 10 FLm diameter a洗er operations in two operatlng rOOmS･ Patients le氏 the roomat the times indicated by closed a汀OWS.

Operations is a practical method to evaluate the potency ofGuidelines for preventlng the transmission of Mycobac‑ventilation system in operating rooms.

terium tuberculosis in health‑care facilities. Morbid.

REFERENCES

2. Nevins, R. G. (1971): Environmental control ofhealth‑care facilities. CRC Crit. Rev. Bioeng., 1 , 217‑239.

Mortal. Wkly. Rep., 43, RR‑13, 1‑132.

1. Centers for Disease Control and Prevention (1994):

207