Operating theatres

For very many years it has been common practice to improve the electrical conductivity of plastics and rubbers by the incorporation of certain additives like special grades of carbon black. Such materials were important, for example, in hospital operating theatres where it was essential that static charges did not build up, leading to explosions involving anaesthetics. 

Glutaraldehyde (1,3-diformyl propane) is a powerful, cold disinfectant. It is used principally in aqueous solution as a biocide and chemical disinfectant. It has been widely used in the health services, e.g. in operating theatres, endoscopy units, dental units and X-ray film processing. 

The PMMA bone cement is formed from a mixture of prepolymer PMMA powder, which contains a free-radical initiator, and liquid MMA monomer. In the operating theatre the powder and liquid are mixed, causing the initiator to dissolve and bring about polymerisation in the monomer component. The powder pre-polymer does not dissolve in the monomer but remains in the newly polymerised materials as a kind of reinforcing filler. 

One of the most potent routes for transmission of bacterial disease is via the air. Cross-infeetion in hospital wards, infeetion in operating theatres, the transmission of disease in elosed spaces such as cinemas and other places of assembly, in the ward rooms and erew s quarters of ships and in submarines are all well known. Of equal importance is the provision of a bacteria-fiee environment for aseptic manipulations generally. Clearly, the disinfeetion of atmospheres is a worthwhile field of study and to this end much research has been done. It is equally clearly important to be able to evaluate preparations claimed to be air disinfeetants. 

Medical assessment of the injured victims was headed by an experienced surgeon, Head of the Surgical Department of Emergency Surgery. Doctors of all specialties were involved with medical assessment. Every injured patient was personally supervised by an assigned doctor starting from the time when the patient was admitted to the operating theatre. 

At each incident 14 operating theatres were functional. Two halls which were transformed into temporary operating theatres were ready as reserve in case of increase in hospitalizations. 

Outbreaks of disease have been caused by those with artificial fingernails. In 2004 there was an outbreak of Klebsiella pneumoniae among premature babies in a US intensive care unit, caused by bacteria from a nurse s artificial nails. A few years previously it was Pseudomonas aeruginosa that threatened several newborn babies in a New York hospital and this was traced to the same cause. In Canada three patients who had had surgery on their spinal cord developed Candida infections of the spinal disks and this was traced to an operating theatre technician who had artificial nails. An intensive care unit in Oklahoma City saw 16 patients die as a result of contracting Pseudomonas aeruginosa from two nurses who had artificial nails. Thankfully such outbreaks are now extremely rare. 

The best anaesthetic vapour was found to be a 1 2 3 mixture of alcohol, chloroform, and ether, known as ACE. Despite being widely used, it was always known that ACE presented a risk, and yet it was the anaesthetic of choice for more than 100 years. Ether caused serious fires and explosions in operating theatres and while the risk of this was small - about one serious incident every 100,000 operations - it was alarming when it happened. Chloroform was not a fire risk but it could be deadly to some patients, killing them within minutes in certain tragic cases, and seriously damaging the liver of others. (Nitrous oxide was less risky, and continues to be used even today, but it does not produce deep anaesthesia.)... 

In the 1980s two more anaesthetics came into use enflurane and isoflurane. These were not metabolised by the liver to the same extent, 2% in the case of enflurane, and only 0.2% of isoflurane. Enflurane was introduced into clinical use in 1981, but isoflurane was delayed because some research appeared to show that it caused liver cancer in mice. This research was repeated by others and shown to be wrong and isoflurane came into general use in 1984. What operating theatre personnel did not like was its off-putting smell. Were there health risks associated with the new anaesthetics A statistical analysis of the side-effects experienced by 17,201 patients on whom they were used was compared with the effects experienced by a similar group on whom halothane had been used. Patients on the newer anaesthetics were more likely to suffer a heart attack and, with isoflurane, palpitations were more common. However, there was no increased risk of the patient dying. 

Roughly a hundred years earlier Sir Joseph Lister suffered exposure to exactly the same total amount of phenol with no blisters and no scarring at all. Sir Joseph conducted surgical operations under a fine spray of a very dilute solution of phenol. The speed of a reaction in solution depends on the concentration of the solution. Thankfully there are better ways of ensuring hygiene in operating theatres now as phenol is nasty stuff. 

Adverse effects. The incidence of nausea and vomiting increases with the duration of anaesthesia. Nitrous oxide interferes with the synthesis of methionine, deoxythymidine and DNA. Exposure of to nitrous oxide for more than 4 hours can cause megaloblastic changes in the bone marrow. Because prolonged and repeated exposure of staff as well as of patients may be associated with bone-marrow depression and teratogenic risk, scavenging systems are used to minimise ambient concentrations in operating theatres. 

About 20% of halothane is metabolised and it induces hepatic enzymes, including those of anaesthetists and operating theatre staff. Hepatic damage occurs in a small proportion of exposed patients. Typically fever develops 2 or 3 days after anaesthesia accompanied by anorexia, nausea and vomiting. In more severe cases this is followed by transient jaundice or, very rarely, fatal hepatic necrosis. Severe hepatitis is a complication of repeatedly administered halothane anaesthesia and has an incidence of 1 50000. It follows immime sensitisation to an oxidative metabolite of halothane in susceptible individuals. This serious complication, along with the other disadvantages of halothane and the popularity of sevoflurane for inhalational induction, has almost eliminated its use in the developed world. It remains in common use other parts of the world because it is comparatively inexpensive. 

The sulfur analogue of pentobarbital, called thiopental (Figure 3.14), is widely used in operating theatres for the induction of general anaesthesia. Thiobarbiturates of this type have a much higher partition coefficient than the oxobarbiturates used as hypnotics (see Chapter 2). As a result, thiopental, when administered intravenously to a vein in the back of the hand, can in a matter of seconds induce unconsciousness that lasts for several minutes. This is sufficient time for the anaesthetist to introduce an airway to the patient and commence general anaesthesia. 

Binding N, Witting U. 1990. Exposure to formaldehyde and glutardialdehyde in operating theatres. Int Arch Occup Environ Health 62 233-238. 

Recommendations for the maximum tolerable number of particles carrying bacteria in operating theatres are 700 per cubic metre for minor operations, and down to 70 or even 15 per cubic metre for dressing burns... 

Importantly, such sophisticated techniques have also been exploited from a highly sensitive sterile-zone of an operation theatre in a hospital to the chemical laboratory for... 

H Malta, AM Thompson, JB Rainey. Does wearing two pairs of gloves protect operating theatre staff from skin contaminations Br Med J 297 597-598, 1988. 

K Wrangsjo, K Oserman, M van Hage-Hamsten. Glove-related skin symptoms among operating theatre and dental care unit persoimel (I). Interview investigation. Contact Dermatitis 30 102-107, 1994. 

Healthcare and hygiene products are an important sector in the field of medicine and surgery. The range of products available is vast but typically they are used either in the operating theatre or on the hospital ward for the hygiene, care and safety of staff, and patients. Table 5.6 illustrates the range of products used in this category and includes the fibres and/or materials used and the method of manufacture. 

Textile materials used in the operating theatre include surgeons gowns, caps and masks, patient drapes, and cover cloths of various sizes (Fig. 5.7). It is essential that the environment of the operating theatre is clean and a strict control of infection is maintained. A possible source of infection to the patient is the pollutant particles shed by the nursing staff, which carry bacteria. Surgical gowns should act as a barrier to... 

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