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Biomedical subjects

O M Lidwell

Publications and source records attributed to O M Lidwell.

At least 19 recordsLinked to original sources
PubMed1994

Ultraviolet radiation and the control of airborne contamination in the operating room.

Ultraviolet irradiation has been employed in operating rooms for more than half a century in attempts to reduce airborne bacterial contamination. Safety considerations have limited its intensity to 25-30 mu w cm-2 and at this level no more than a fourfold reduction has resulted. In recent studies intensities up to 300 mu w cm-2 have been used without untoward effects, and, at the highest intensity, contamination as low as that obtained with ultraclean air ventilation systems was obtained. However this was only achieved in an operating room where the level of airborne contamination before the introduction of the radiation was already much lower (around one-fifth) than that usually observed, and the reduction attributable to the radiation was still only about 12-fold.

Air Microbiology↗
PubMed1988

Air, antibiotics and sepsis in replacement joints.

Reducing bacterial contamination of the wound by limiting dispersal from the operating staff through the wearing of special occlusive clothing and by employing directional flow ventilating systems substantially reduces the risk of later joint sepsis. Inhibiting growth of those bacteria which reach the wound, by means of perioperative antibiotics, further reduces the incidence of joint sepsis. When all three means are used together the sepsis rate in the years after operation can be reduced to no more than a few per thousand. The hospital costs of any or all of these measures, in terms of the cases of sepsis avoided, are several times less than the costs of treating a septic joint.

Air Microbiology↗
PubMed1987

Ultraclean air and antibiotics for prevention of postoperative infection. A multicenter study of 8,052 joint replacement operations.

To determine the value of ultraclean air in operating rooms, 8,052 operations for total hip- or knee-joint replacement were followed up for 1-4 years. For operations done in ultraclean air, bacterial contamination of the wound, deep joint sepsis, and major wound sepsis were substantially less than for operations done in conventionally ventilated rooms. Sepsis was also less frequent when prophylactic antibiotics had been given. The two precautions acted independently so that the incidence of sepsis after operation in ultraclean air and with antibiotics was much less than that when either was used alone. Wound sepsis was associated with an enhanced risk of joint sepsis. Staphylococcus aureus was the commonest joint pathogen, but infections with other organisms, often considered to be of low pathogenicity, were almost as numerous. Most S. aureus infections were traced to sources in the operating room.

Air Microbiology↗
PubMed1986

Clean air at operation and subsequent sepsis in the joint.

When Charnley and others began to do substantial numbers of arthroplasties, they met a high incidence of subsequent failure from sepsis. There was at that time a revival of interest in the possibility that surgical sepsis originated from airborne bacteria, and engineering developments had provided the means for attaining much cleaner atmospheres. Over a period of ten years, Charnley reduced airborne contamination by more than 100-fold, and his sepsis rate fell, without using antibiotics, by tenfold. He had, however, made other procedural changes, and there were those who reported equally good results without using the ventilation and clothing systems he had devised, although usually they had given prophylactic antibiotics. The results of recent randomized studies have confirmed that considerable reduction in the sepsis rate can be obtained by operating in ultraclean air but that similarly low rates can be achieved with normal ventilation when prophylactic antibiotics are given. In addition, the two methods are effective independently, and used together sepsis rates in the joint after total arthroplasty have been reduced to a few per 1000.

Air Pollution↗
PubMed1985

Extended follow-up of patients suspected of having joint sepsis after total joint replacement.

During an average follow-up time of about 2 1/2 years after total hip or knee-joint replacement in 8052 patients, suspected joint infection was recorded in 85 patients whose joints had not been re-operated during that period. The hospital records of 72 of these patients were examined after a further period, averaging about 5 years. Thirty-five of these had suffered continuing major problems with the joint, 18 of which had been revised, and a further 9 joints needed such treatment. Infection was confirmed in 17 of the 35. These numbers are proportionately about three times greater than those observed among a set of matched controls followed-up for a similar period. The evidence from the extended follow-up suggests that the failure rate, unassociated with infection, reached about 5% by 7 years after operation and that late infections, manifested between about 2 1/2 and 7 years after operation, were about as frequent as those confirmed during the first 2 1/2 years.

Anti-Bacterial Agents↗
PubMed1984

Infection and sepsis after operations for total hip or knee-joint replacement: influence of ultraclean air, prophylactic antibiotics and other factors.

Operating in ultraclean air and the prophylactic use of antibiotics have been found to reduce the incidence of joint sepsis confirmed at re-operation, after total hip or knee-joint replacement. The reduction was about 2-fold when operations were done in ultraclean air, 4.5-fold when body-exhaust suits also were worn, and about 3- to 4-fold when antibiotics had been given prophylactically. The effects of ultraclean air and antibiotics were additive. Wound sepsis recognized during post-operative hospital stay was, however, reduced by these measures only when it had been classed as major wound sepsis. This was reported after 2.3% of operations done without antibiotic cover in conventionally ventilated operating rooms. Joint sepsis was much more frequent after wound infection and especially after major wound sepsis, although most cases of joint sepsis were not preceded by recognized wound sepsis. This was particularly noticeable after major wound sepsis associated with Staphylococcus aureus; after 37 such infections the same species was subsequently found in the septic joint of 11 patients. The sources of wound colonization with Staph. aureus, when this was not followed by joint sepsis, appeared to differ widely from those where joint sepsis occurred later. Operating-room sources could be found for most of the latter and the risk of infection appeared to be similar with respect to any carrier in the operating room whether a member of the operating team or the patient. For wound colonization that was not followed by joint sepsis, operating-room sources could only be inferred for fewer than half and of these more than one half appeared to be related to strains carried by the patient at the time of operation. During the follow-up period, which averaged about 2 1/4 years with a maximum of four years, there were, in addition to the 86 instances of deep joint sepsis confirmed at re-operation, 85 instances in which sepsis in the joint was suspected during this period but was not confirmed, because re-operation on the joint was not done. The incidence of suspected joint sepsis was, like that of confirmed joint sepsis, less after operations done in ultraclean air: 1/2.5, or with prophylactic antibiotics, 1/2.3 Although re-operation was more frequent on the knee-joint than on the hip, and pain after the initial operation was more frequent after knee operations, there was no evidence that this was the result of any increased risk of infection.(ABSTRACT TRUNCATED AT 400 WORDS)

Air↗
PubMed1984

The cost implications of clean air systems and antibiotic prophylaxis in operations for total joint replacement.

The effect on sepsis of the use of prophylactic antibiotics and measures for reducing the level of airborne contamination in the operating room has been related to the costs of these measures and of dealing with a septic joint. While antibiotic prophylaxis is the most cost effective, the benefits that may be obtained from the introduction of cleaner air also appear to be worthwhile, even when considered solely in terms of hospital costs.

Air Microbiology↗
PubMed1983

Airborne contamination of wounds in joint replacement operations: the relationship to sepsis rates.

During operations for total joint replacement done in operating rooms with conventional ventilation the mean air contamination varied considerably among the 15 hospitals studied. The range was from 51 to as many as 539 bacteria-carrying particles per cubic metre. When the data from all the hospitals were grouped according to the mean level of bacterial airborne contamination, including operations done in control and in ultraclean air, there was a good correlation between the air contamination and the joint sepsis rate. There was also a correlation between the mean values of air contamination and the numbers of bacteria isolated from wound wash-out samples; but the apparent efficiency of the sampling method varied a great deal among the hospitals carrying out this procedure. From this data it would seem that by far the largest proportion of bacteria found in the wound after the prosthesis had been inserted reached it by the airborne route. With the mean air contamination found in the control series, 164 bacteria-carrying particles per cubic metre, this proportion was as much as 95 per cent. The risk of joint sepsis varied widely among the 19 hospitals. The differences between the highest and lowest being probably as much as 20-fold. However, the effect of an ultraclean air environment was asimilar at all hospitals.

Air Microbiology↗