Endoscopy - Dangers of the optic ‘scope’

Endoscopy is the direct visualisation of the digestive tract using an endoscope, a flexible tube with a camera mounted on it that is small enough to pass into cavities in the body such as the stomach, colon, lungs and oesophagus.

For years, this seemingly safe procedure has been fraught with risks, causing problems such as perforation of the wall of the oesophagus, stomach or duodenum (the first section of the small intestine), infections and adverse reactions to anaesthetics. In some cases, the procedure has even led to death.

One study performed across 36 UK hospitals found that 1 in 2000 patients died within 30 days of undergoing endoscopy. One-third of these deaths were due to complications of sedation. In addition, there were 20 perforations in 774 procedures, eight of which were fatal, giving a death rate of nearly 1 in 100 (Gut, 1995; 36: 462-7).

Since this report, there has been no large-scale audit of the procedure. However, reports of deaths continue (Med J Aust, 2002; 176: 147).

As the procedure is invasive, sedation is used to prevent interference from patient restlessness. Anaesthetics such as propofol are commonly used, but patients have been known to become unconscious because of the dosages used, usually by untrained doctors.

Another problem is that the cleaning procedures required for endoscopes are time-consuming and arduous. But without rigorous disinfection and cleaning, the risk of cross-contamination is high. The US Food and Drug Administration (FDA) recently reported that 24 per cent of endoscopes tested produced 100,000 or more different types of bacteria even after cleaning and disinfection.

The report raised concern over the risk of endoscopic cross-contamination. Although there are no known cases of HIV infection due to endoscopy, there is evidence of such transmission of hepatitis B and C, and Creutzfeldt-Jakob disease (Gut, 1983; 24: 171-4; J Clin Gastroenterol, 1999; 28: 290).

Epidemics of mycobacterial infections have also been due to contaminated endoscopic equipment or disinfecting machines (J Infect Dis, 1989; 159: 954-8).

The Society of Gastroenterology Nurses and Associates published recommended guidelines in 1990 for cleaning procedures for endoscopic equipment. However, the report admits that difficulties arise due to the endoscope’s 'complex and fragile structure'.

Another problem surrounding endoscopic procedures concerns the disinfectants required to clean the endoscopic equipment. These agents have been found to be highly toxic, causing side-effects such as swelling of the tongue and bloody diarrhoea in both patients and the medical staff exposed to inadequately rinsed equipment (Endoscopy, 1995; 27: 139-40).
Megan McAuliffe