Risk of transmission of HIV disease from patient to surgeon
The surgeon is regularly exposed to blood, which is the most infective medium for HIV transmission. The risk must be greater where there are more HIV particles in the blood and this occurs during the earliest and later stages of the disease . Thus, patients undergoing surgery who have had a recent seroconversion illness and who may be unaware that they are HIV positive are infectious, as well as patients who are known to be HIV positive. The extent of risk to the surgeon depends on the prevalence of HIV in the patient population, the number of procedures carried out by the surgeon, and the length of the period of risk. It is estimated that the risk to a surgeon working in a high-prevalence American or European inner city area over a 30-year career is roughly a one in 800 chance of acquiring HIV infection. In Africa, where the prevalence of HIV disease is thought to be much higher and the risk of HIV infection in blood products is also higher, a similar career risk has been estimated to be as high as one in four.
Sources of infection
The principal route of occupationally acquired HIV infection in healthcare workers is by skin perforation with a hollow needle containing HIV-infected blood. Although infection has been reported after solid needle skin perforation, the risk seems to be about 10-fold less than with hollow needle perforation where more blood may be injected. Extensive splashing of mucous membranes and skin, as occurred with spillage of a pack of blood over a nurse, has also been reported to produce HIV infection.
Although screening of all patients for HIV infection before routine surgery would identify a substantial proportion of patients who might infect the surgeon, this has not, been accepted because of political and social constraints in most countries. The risk of contamination to the surgical team can be reduced by the use of ‘universal precautions’ involving wearing either safety spectacles or a face mask , and a gown which provides waterproof protection to the surgeon’s anterior trunk and arms. In addition, boots rather than open-toed shoes should be worn to improve protection to the feet should something sharp be dropped. Needle-stick injuries to the hands most frequently occur on the index finger and palm adjacent to the thumb of the nondominant hand. This is presumably a result of passing the needle through tissue with a needle holder held by the dominant hand and attempting to locate the tip of the needle with the nondominant hand which is also used to retract tissue. Skin contamination from glove perforation can be reduced approximately fivefold by wearing two pairs of gloves. It is usually more comfortable if the larger-sized glove is worn on the inside next to the skin and a half-size, smaller glove is worn as the outer second layer.
The most important operative precaution is to carry out the procedure in an orderly manner. Surgical assistants should be kept to a minimum and should be instructed not to move while the operation is proceeding. If the assistants’ position is to be adjusted then the operating surgeon should stop operating while changes are being made. This should avoid the risk of the operating surgeon injuring an assistant’s hand while it is being moved across the operative field. The operation should proceed in a slow and methodical manner with meticulous attention to haemostasis, taking care to avoid unexpected rapid bleeding which changes the tempo of the procedure and increases the risk of inadvertent injury to the operators. No sharp instruments or scalpels should be passed across the operative field from hand to hand. All instruments are passed from the scrub nurse to the surgeon and back to the scrub nurse in a dish (Fig. 9.11), thereby reducing the risk of injury while passing instruments. It is not practicable to adopt universal precautions in all patients, although the precautions related to operative technique should be carried out with all cases regardless of HIV status. It may be helpful to screen patients for factors in the history which are known to predict a higher risk of HIV positivity. These factors are:
• homosexual lifestyle;
• a history of intravenous drug abuse;
• a history of haemophilia treated with factor VIII;
• residents of sub-Saharan Africa;
• the partners of the above, higher risk groups.
Procedure in the event of contamination with infected blood
A surgeon who has been contaminated with HIV-infected blood should immediately clean the contaminated area by washing under running water. Where the source patient comes from a high-risk group and the HIV status is unknown, it is important that postexposure prophylaxis to HIV should be offered. This should be started within 1 hour of the injury where possible, so it is inappropriate to await the result of an HIV antibody test in a high-risk patient before commencing the prophylaxis. The prophylaxis consists of: zidovudine 250 mg twice daily, lamivudine 150 mg twice daily and indinavir 800 mg three times daily for I month. The surgeon should then be given hepatitis prophylaxis since the risk of developing hepatitis after contamination with blood from a high-risk patient is greater than the risk of HIV infection. A baseline HIV test should be carried out immediately since seroconversion will not have occurred immediately after injury. The HIV test should then be repeated approximately 12 weeks after contamination to determine whether seroconversion has occurred. This is obviously a period of great anxiety, and advice about domestic relations and procedures at work should be obtained from an HIV counsellor.
Where a medical practitioner discovers that he or she is HIV positive, the requirement of the UK General Medical Council is that ‘if their duties involve performing or assisting in surgical or invasive procedures, they must seek and act upon occupational advice on any modifications or limitations to their duties which may be necessary for the protection of patients’.
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