upper gastrointestinal endoscopy with a flexible fiberoptic endoscope is a useful procedure that has been used for many years , but it involves the potential hazard of transmitting infectious agents , such as the hepatitis b ( hb ) virus .
glouberman and whalen have suggested that transmission of the hb antigen by a fiberoptic endoscope is a distinct possibility , but it has not yet been proved conclusively . hb surface antigen ( hbsag ) is detectable in all kinds of human secreta , and transmission of hb via the nonparenteral routes such as saliva , gastric juice , urine , and stool has been documented .
the dentist , surgeon , physician in oncology and physician in a dialysis unit have a higher incidences of serum hbsag positivity than the physicians in other specialties .
fifty patients , all seropositive for hbsag as determined by the rpha ( reverse passive hemagglutination assay ) method , underwent an upper gastrointestinal examination with a flexible fiberoptic endoscope .
the diagnoses of these patients were viral hepatitis 19(38.0% ) , gastritis 14(28.0% ) , liver cirrhosis 11 ( 22.0 ) , gastric ulcer 4(8.0% ) , and hepatocellular carcinoma 2 ( 4.0% ) ( table 1 ) .
as preparation for endoscopy , patients fasted from the evening before the examination day until the endoscopic procedure .
fifteen to thirty min , before the procedure , 1.0 mg of atropine were injected intramuscularly .
we collected fluid adherent to the endoscope ( gastric juice , and saliva ) , by wiping it directly into small glass tubes .
all of the samples were tested for hbsag by the ria ( radioimmunoassay ) . in ria
, we used an austria ii-123 kit of abbott laboratories , chicago , asssay procedure b. the cut off value is the net cpm of the negative control mean ( ncx ) times the factor 2.1 .
gastric juice aspirated through the endoscope in the case of 50 patients was positive for hbsag in 16 of the cases ( 32.0% ) ( table 2 ) .
the saliva was positive for hbsag in 21 ( 42.0% ) ( table 3 ) .
the secretions adherent to the endoscope after extubation were positive in 15 of the 48 cases in which examinations were done ( 31.3% ) ( table 4 ) . as a control ,
the gastric juice , saliva and fluid adherent to the endoscope sampled during the endoscopic examination were all negative for hbsag in ail 10 cases ( table 5 ) .
many investigators have suggested the possibility that hb is sometimes transmitted through endoscopy , but evidence of this has been lacking .
we examined saliva and gastric juice collected during endoscopic examinations done on 50 carriers of hb , and material adherent to the endoscope .
it has been shown that hbsag positive serum is infective at a dilution of 1:10 if given parenterally , and it has been reported that 0.5ml of positive serum could transmit hb by an oral route , but the exact oral dose capable of transmitting the disease is not known .
there is epidemiological evidence that there are a large number of hbsag particles in saliva , sufficient to transmit hb infection .
those reports suggested that even a minimal amount of hbsag in saliva , gastric juice , and blood can effect transmission . in our study
the test for hbsag was positive in 42.0% of the saliva samples , in 32.0% of the gastric juice specimens , and in 31.3% of the material adherent to the endoscope .
morris et al . performed endoscopy in 32 patients inadvertently following an emergency endoscopy in a patient who was later found to be positive for hbsag .
they followed these patients and tound that none of them developed jaundice or biochemical abnormalities .
mcdonald and silverstein also reported that no clinical and biochemical signs of liver disease developed in 4 patients who underwent endoscopy with a scope that had been used in patients seropositive for hbsag .
and mcdonald and silverstein washed the endoscope thoroughly to remove adherent materials and cleaned it with 70% alcohol for each endoscopic examination , and suggested that the possibility of hb transmission was reduced to a minimum by this procedure .
by contrast , there are many pessimistic physicians who doubt whether this disinfection procedure will absolutely prevent transmission of hepatitis by endoscopy .
although there was no incidence of endoscope - transmitted hb , morris et al . began using 2% glutaraldehyde as a disinfectant .
mcdonald and silverstein tried not to do endoscopy on patients who were positive for hbsag and jaundiced .
bond and moncada recommend 2% glutaraldehyde or 8% formalin , because alcohol will not inactivate hb virus completely . according to glouberman
, 2% glutaraldehyde can not destroy the infective particles , but the blood treated with 2% glutaraldehyde would not transmit virus even though hbsag should still be present in the disinfected blood , because there is no relation between the viral infectivity and its immunologic activity that will give a positive test .
he also suggested that hbsag could be destroyed by exposing it to ethylene oxide gas for 16 hours . besides ethylene oxide gas , 90c moist heat for 2 hours .
85c moist heat for 1 hour or 100c for 10min , can destroy the infectivity .
these method can not be applied to fiberoptic instruments , because the maximum heat tolerance of the olympus or acmi fiberoptics is 5060c . of ethylene oxide gas and 2% glutaraldehyde .
prefer the latter and suggest 15 min , of soaking in it because the former is time - consuming and more expensive . in the endoscopy room of our hospital
, we use the following procedure for disinfection : the fiberoptic endoscopes are washed thoroughly in running water , and 70% alcohol is used to cleanse them after the adherent materials have been removed .
almeida et al . emphasized that hb virus can be transmitted by air , and that the medical personnel exposed to the secreta of patients may become infected in a small endoscopic room .
it has been reported that the bacteria in the oral cavity of a patient is demonstrable in the air , and some endoscopists suggest that both the endoscopist and his / her co - workers should wear masks to protect themselves .
chalmers et al . suggested that hbsag - positive physicians , nurses , dentists , and other medical personnel can transmit hb virus to patients , based on an outbreak of hepatitis transmitted by such individual .
sultz et al . also noted that hb virus has been transmitted to patients through the wounded hands of an hbsag - positive physician in the giving of injections , the manipulation of medical devices , or the intubation of an endoscope .
although we did not investigate endoscopic biopsy forceps and cytology brushes , if contaminated by blood in the stomach of the patient positive for hbsag , they could be a vehicle for transmission of hb virus infection .
proposed that endoscopic accessories should be either disposable or exposed the required length of time to ethylene gas after each use , and whalen suggested that a temperature of 250c at 15 1bs , pressure for 15 min , would provide an adequate protection against hb virus . in summary , the need for ensuring that the endoscope is free of contamination with hb virus is a real one , particularly in view of the fact that endoscopic cholangiopancreatography is now commonly used in patients with jaundice .
 gastric juice , saliva , and fluid adherent to the endoscope were collected from 50 patients who were seropositive for hepatitis b surface antigen ( hbsag ) during the endoscopic examination of the upper gastrointestinal tract , and examined for hbsag , using the radioimmunoassay . 
 a positive test was obtained from 42.0% of the saliva samples , in 32.0% of the gastric juice specimens , and in 31.3% of the fluid adherent to the scope . 
 these results should be taken as a warning , that calls for a more careful screening of the patients and disinfection of the endoscope . 
INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION