Impact of laminar air flow on operating room contamination, and surgical wound infection rates in clean and contaminated surgery

The research on the particle concentration distribution of directed airflow in cleanrooms for operators

Existing research of non-unidirectional cleanrooms generally suggests that lower-side return air outlets provide better control effect on indoor particle concentration. As a result, there has been relatively less focus on return air outlets. However, installing return air outlets oriented towards operators as particle emission sources can reduce the impact on process layout and improve space utilization, while also provide less impact from upper particle emission sources on the workbench area. To investigate the characteristics of return air outlet for operators (abbreviated as H), this study compared the particle concentration distribution, non-uniformity, and purification efficiency of return air oultet H and the traditional lower-side (abbreviated as L) return air outlets by experiments and CFD simulations. Based on the theory of mass conservation, the expression of required air supply volume under equivalent cleanroom conditions was derived. Under corresponding experimental and simulation conditions, the particle concentration differences range from 2.0% to 12.7% for return air outlet H and from 12.4% to 33.2% for return air outlet L, and these differences gradually decrease with the air exchange rate (ACH) increases. The results show that ACH = 20 is sufficient for cleanliness requirements with return air outlet H when there is one person in the cleanroom, while a higher rate of ACH = 35 is needed when there are two persons. Although lower-side return air outlets have certain potential for reducing particle concentration in the cleanroom, increasing the air exchange rate remains the most effective method to control indoor particle concentration. Compared to the traditional lower-side return air outlet L, the ranges of the non-uniformity coefficients for return air outlet H and L are 0.50 to 0.67 and 0.45 to 0.53, respectively. The average non-uniformity coefficient differs by 11.9%, and there is not a significant difference in uniformity with more than 20 air changes per hour. The use of return air outlets H only requires an additional 11% of air supply volume to achieve the same cleanliness, demonstrating its effectiveness in controlling particle concentration. It is suitable for cleanrooms with higher requirements for workbenches and for cleanrooms with restricted floor usage or requiring flexible layouts. The study also explores the impact of width of return air outlet oriented towards operators as particle emission sources, the results show that the larger-sized outlets facilitate the particle discharge and control the particle distribution inside the room.

Antibiotic prophylaxis and surgical site infections in orthognathic surgery - a retrospective analysis

BACKGROUND

This study was conducted to determine surgical site infection (SSI) rates and potential risk factors as well as to evaluate antibiotic prophylaxis in orthognathic surgery.

METHODS

This retrospective observational study included patients who received orthognathic surgery. SSIs and their management were assessed for up to one year post-operatively. The applied antibiotic regime and other possible influencing factors (smoking, age, site of infection, drainage, duration of surgery, displacement distances, craniofacial malformations) were assessed.

RESULTS

In total 291 patient met the inclusion criteria (56.7% female). The mean age at surgery was 25.5 ± 8.5 years. Fifty-four patients (18.6%) were diagnosed with a craniofacial malformation. Relevant previous surgeries were documented in about one quarter of included patients (n = 75). Ninety-two percent of patients (n = 267) received intraoperative single-dose antibiotic prophylaxis. Surgical site infections occurred in 12.4% (n = 36) of patients. There was a significant association between postoperative infections and type of surgery (P = .037) as well as type of drainage (P = .002). Statistical analyses also revealed a higher prevalence of smokers (P = .036) and previous surgically assisted rapid palatal expansion (SARPE) (P = .018) in the infection group. Furthermore, no significant relationships were observed between postoperative infections and various co-factors (i.e. antibiotic regime, age at surgery, gender, associated craniofacial malformations, surgery duration, displacement distances, mandibular setback vs. advancement).

CONCLUSION

Low rates of SSIs occurred following an intraoperative single-dose antibiotic regime. None of the SSIs had a significant effect on the final surgical outcome. Present data do not warrant escalation of the antibiotic regimen. Postoperative smoking and capillary drainage should be avoided.

Novel Designed Surgical Drapes Reducing Fluid Permeability in the Surgical Critical Area of a Sterile Operation Interface: A Randomized Controlled Trial

Aim. To compare the impact and cost effects of medical long fiber polyester drapes and cotton fabric drapes on operative sterile operation interfaces. Background. The comparison of the properties of the commonly used surgical drapes materials in terms of leakage, device slip, and prevention of intraoperative adverse events is not clear. Method. A prospective randomized controlled study was conducted in the operating room of a tertiary hospital in Chengdu, China. A total of 400 patients who underwent urology surgery were enrolled and randomly divided into two groups by computer, the study group (200 cases) selected the new long-fiber polyester cloth, while the control group (200 cases) selected conventional cotton fabric surgical drapes during the operation to maintain a sterile operating interface. The impermeability and water absorption of surgical drapes, the rate of device slip and skin scald in surgical patients, and the cost effect of the two kinds of surgical drapes were compared. Results. The long fiber polyester surgical drapes were superior to conventional cotton cloth in water absorption (g/m2) (835 ± 15.8 VS 225 ± 21.0, t = 328.261, $P<0.001$ ), preventing surgical site infections (2.5% VS 8.0%, χ2 = 6.081, $P=0.014$ ), device slip (7.5% VS 17.0%, χ2 = 8.396, $P=0.004$ ), patients from burning (0 VS 1, Fisher $P=1.0$ ), and total cost per use ($) (0.83 VS 0.96–1.09). Conclusion. Long fiber polyester fabric has a stronger antipenetration ability of fluid and microorganisms thus forming an effective protective barrier. It also has strong hygroscopicity, and its special design can prevent the occurrence of sliding of surface instruments and skin scald in patients. In addition, its cost effect is superior. Implications for Nursing Management. Operating room nursing managers can introduce long fiber polyester drapes into the selection of medical textiles to construct aseptic surgical barriers and prevent surgical site infection.

Development and evaluation of a fluidic facemask for airborne transmission mitigation

Recently, a fluidic facemask concept was proposed to mitigate the transmission of virus-laden aerosol and droplet infections, such as SARS-CoV-2 (COVID-19). This paper describes an experimental investigation of the first practical fluidic facemask prototype, or "Air-Screen". It employs a small, high-aspect-ratio, crossflow fan mounted on the visor of a filter-covered cap to produce a rectangular air jet, or screen, in front of the wearer's face. The entire assembly weighs less than 200 g. Qualitative flow visualization experiments using a mannequin clearly illustrated the Air-Screen's ability to effectively block airborne droplets (∼10⁰ µm) from the wearer's face. Quantitative experiments to simulate droplets produced during sneezing or a wet cough (∼10² µm) were propelled (via a transmitter) at an average velocity of 50 m/s at 1 m from the mannequin or a target. The Air-Screen blocked 62% of all droplets with a diameter of less than 150 µm. With an Air-Screen active on the transmitter, 99% of all droplets were blocked. When both mannequin and transmitter Air-Screens were active, 99.8% of all droplets were blocked. A mathematical model, based on a weakly-advected jet in a crossflow, was employed to gain greater insight into the experimental results. This investigation highlighted the remarkable blocking effect of the Air-Screen and serves as a basis for a more detailed and comprehensive experimental evaluation.

Current and potential approaches on assessing airflow and particle dispersion in healthcare facilities: a systematic review

An indoor environment in a hospital building requires a high indoor air quality (IAQ) to overcome patients' risks of getting wound infections without interrupting the recovery process. However, several problems arose in obtaining a satisfactory IAQ, such as poor ventilation design strategies, insufficient air exchange, improper medical equipment placement and high door opening frequency. This paper presents an overview of various methods used for assessing the IAQ in hospital facilities, especially in an operating room, isolation room, anteroom, postoperative room, inpatient room and dentistry room. This review shows that both experimental and numerical methods demonstrated their advantages in the IAQ assessment. It was revealed that both airflow and particle tracking models could result in different particle dispersion predictions. The model selection should depend on the compatibility of the simulated result with the experimental measurement data. The primary and secondary forces affecting the characteristics of particle dispersion were also discussed in detail. The main contributing forces to the trajectory characteristics of a particle could be attributed to the gravitational force and drag force regardless of particle size. Meanwhile, the additional forces could be considered when there involves temperature gradient, intense light source, submicron particle, etc. The particle size concerned in a healthcare facility should be less than 20 μm as this particle size range showed a closer relationship with the virus load and a higher tendency to remain airborne. Also, further research opportunities that reflect a more realistic approach and improvement in the current assessment approach were proposed.

Analysis of the Effect of Holistic Nursing in the Operating Room Based on PDCA and Evidence-Based Nursing in the Otorhinolaryngology Operating Room: Based on a Retrospective Case-Control Study

Objective

Based on a retrospective case-control study, this study aims to explore the effect of holistic nursing in operating room based on PDCA (plan, do, check, and action) process and evidence-based nursing (EBN) in a ear, nose, and throat operating room.

Methods

About 200 patients who underwent otorhinolaryngology surgery in our hospital from January 2019 to September 2021 were enrolled. According to the difference of nursing mode, patients were assigned into a control group and study group; holistic nursing in operating room was included in control group, and holistic nursing in the operating room based on PDCA and EBN was included in study group. Nursing satisfaction, hypothermia, chills, restlessness, related indexes of operating room, nursing quality scores of operating room, and individual quality control scores were compared.

Results

First of all, we compared the nursing satisfaction, the study group was very satisfied in 69 cases, satisfactory in 30 cases, general in 1 case, the satisfaction rate was 100.00%, while in the control group, 46 cases were very satisfied, 34 cases were satisfied, 13 cases were general, and 7 cases were dissatisfied, the satisfaction rate was 93.00%. The nursing satisfaction of the study group was higher compared to the control group (P < 0.05). Second, we compared the incidence of hypothermia, chills and restlessness. The incidence of hypothermia, chills, and restlessness in the study group was lower compared to the control group (P < 0.05). The time of tracheal tube extubation, PACU stay time, postoperative hospitalization time, hospitalization cost, and operation time in the study group was significantly lower compared to the control group (P < 0.05). In terms of the scores of nursing quality in the operating room, the instruments and equipment management, equipment preparation, nurses' cooperation skills, disinfection and isolation quality, and total score in the study group were higher compared to the control group (P < 0.05). Finally, we compared the scores of individual quality control examination. The scores of ward management, rescue, therapeutic articles, drug management, first-level nursing, nursing documents, and head nurse management in the study group were higher compared to the control group (P < 0.05).

Conclusion

Incorporating the concepts of PDCA and EBN into the overall care of the operating theatre is effective for patients in the ENT operating theatre. Our results show that this care can be effective in improving patients' surgical indicators, reducing the incidence of postoperative infections, shortening postoperative resuscitation and length of stay, reducing hospital costs, and promoting surgical patient satisfaction. While further multicenter studies are necessary, this series of nursing interventions remains worthy of replication in the clinical setting.

Comparison of operating room air distribution systems using the environmental quality indicator method of dynamic simulated surgical procedures

BACKGROUND

Ensuring aseptic airborne environments for sterile fields and back instrument tables in operating rooms (ORs) is crucial to reducing microbial and particle contamination during surgery. Configurations of in-ceiling air delivery mechanisms impact the effectiveness of the system at eliminating contamination in critical zones.

METHODS

The environmental quality indicator method was used to assess airborne environments in ORs equipped with a single large diffuser (SLD), a multidiffuser array (MDA), or a 4-way throw diffuser during dynamic, simulated surgical procedures. Environmental quality indicators measured included particles, microbes, carbon dioxide, velocity, humidity, and temperature at 26 air changes per hour.

RESULTS

SLD ORs performed better than MDA ORs and 4-way throw diffuser ORs at removing microbes and carbon dioxide from the sterile field (P < .05). SLD ORs had higher velocity and lower temperature over the sterile field than the other 2 ORs (P < .05). MDA ORs had lower total particle counts than the other ORs (P < .05). The sterile fields in all ORs were cleaner than the respective back instrument tables (P < .05).

CONCLUSIONS

Air delivery systems that eliminate blockages to uniform airflow directly over sterile zones, such as boom mounts and access panels, and deliver unidirectional, downward flow of clean filtered air provided a cleaner airborne environment within the sterile field. Expansion of air delivery systems to include areas outside the sterile field, where other surgical aides reside, may further reduce contamination within critical zones.