Forced-Air Warming Discontinued: Periprosthetic Joint Infection Rates Drop

Epidemiology and prevention of surgical site infection in Japan

Healthcare-associated infection control practices in Japan were not commonly acknowledged until mid-1980s, when an academic society focusing on infection control was founded and large academic hospitals began to establish infection control departments. In the late 1990s, the society established a nationwide surveillance system mainly focusing on surgical site infection (SSI). Coincidentally, the guideline for the prevention of SSI published by the US Centers for Disease Control and Prevention (CDC) was revised in 1999. It was translated into Japanese, and has been widely referenced in Japanese clinical practices. Since then, both epidemiological research and preventive practices in Japan have been developed. Overall SSI incidence was about 10% in the early 2000s, but fell to 7% by 2007, with a further reduction to 5% in 2020. A large SSI database cohort created through surveillance enabled us to conduct research regarding risk factors for SSI following various types of surgery. In mid-2010s, the revision of CDC's SSI prevention guideline and the new one by the World Health Organization were published. Novel evidence-based SSI prevention practices such as normal body temperature and antiseptic-impregnated sutures are recommended, and have been timely introduced into Japanese surgical practice. However, many of the practices and devices shown to be effective in preventing SSI are not approved for reimbursement by public healthcare insurance in Japan, which has so far prevented those measures from being widely used in Japanese healthcare.

Effect of commonly used lavage solutions on the polymerization of bone cement

INTRODUCTION

Little is known about the impact irrigation solutions have on the material properties of cement used in hip and knee arthroplasty. We sought to compare the effect of three commonly used lavage solutions on cement polymerization.

METHODS

Ten groups were used for cure and mechanical testing: two cement controls, and eight cement groups mixed with test solutions. Test solutions included a commercially available benzalkonium chloride/citric acid solution (BCS), chlorhexidine gluconate (0.05%) (CHG), povidone-iodine 0.35%, and normal saline added at cement mixing onset. Cement dough-time, set-time, and compression testing were performed following The American Society for Testing and Materials guidelines.

RESULTS

Povidone-iodine had shorter dough-time (1min 34sec, sd 1min 5sec) versus controls (1min 56sec, sd 1min 35sec), p=0.0419. Cement exposed to all lavage samples had significantly reduced set-time. Compressive strength was reduced for all surgical lavages (p<0.001). Pairwise testing revealed that all lavage treatments reduced offset strength versus controls (p<0.001).

CONCLUSION

Bone cement exposed to lavage solutions during the cement mixing-phase showed accelerated set-times and decreased compressive strength. If bone is not dry, and cement has not finished mixing at the time of application, cement curing time may be shortened. Additionally, bone cement should reach dough phase prior to pre-closure surgical lavage.

LEVEL OF EVIDENCE

III; case control study.

Forced-Air Convection Versus Underbody Conduction Warming Strategies to Maintain Perioperative Normothermia in Patients Undergoing Total Joint Arthroplasty

Background

Forced-air warming is an established strategy for maintaining perioperative normothermia. However, this warming strategy can potentially contaminate the surgical field by circulating nonsterile air. This study aimed to determine whether changing practice away from this method resulted in non-inferior rates of perioperative hypothermia.

Methods

We performed a chart review of primary total hip and knee arthroplasty patients from 2014 to 2017, when the strategy of intraoperative forced-air warming (FAW) was changed to preoperative FAW along with intraoperative underbody conduction warming (CW) with an underbody warming mattress. Data included patient temperatures throughout all phases of care, blood loss and transfusion requirements, length of postanesthesia care unit (PACU) and hospital stays, and 30-day infection and mortality.

Results

A total of 769 charts were reviewed; 349 patients underwent surgery before the practice change and 420 after. Mean (SD; 95% CI) body temperatures at the time of incision were lower for group 1 than for group 2 (34.55 vs 35.52 °C [0.97 °C; 95% CI, 0.72-1.23 °C]). The average nadir of intraoperative body temperature was lower for group 1 than for group 2 (difference of means, 0.44 °C; 95% CI, 0.18-0.71 °C). Group 2 had a higher percentage of patients who presented hypothermic (temperature <36.0 °C) on arrival in the PACU (12.9% vs 7.7%).

Conclusion

Preoperative convective warming combined with intraoperative underbody conductive warming maintains normothermia during primary total joint arthroplasty and is non-inferior to forced-air intraoperative warming alone.

Forced Air Warming System: Evaluation of Internal System Contamination

BACKGROUND

Despite the indisputable need to prevent peri-operative hypothermia, some evidence in the literature questions the possible role of forced air warming systems as a risk factor for the occurrence of surgical site infection. The objective of the study is to evaluate the micro-biologic safety of a forced air warming systems (FAW) in relation to the risk of emission of micro-organisms in the surgical environment.

METHODS

A quantitative, descriptive-exploratory laboratory study performed in a large hospital. An evaluation of possible internal contamination was performed by collecting air from the hose onto plates containing Trypticase Soy Agar. The experiment was performed in triplicate two months after replacing the filter and again after six months using a random sample of 50% of the FAW in use, which corresponded to 13 FAW and a total of 75 samples.

RESULTS

Among the 39 samples analyzed in the first stage, only nine (23.1%) plates presented microbial growth of one or two colonies, while only six (16.7%) plates of the 36 evaluated samples in the second phase had growth of one or two colonies.

CONCLUSIONS

This study showed small microbial growth of culture after 48 hours after filter replacement. New investigations that correlate the findings of micro-biology analysis and the occurrence of surgical site infection should be conducted.