Authors (including presenting author) :
CHEUNG TH (1) CHAU PM (1) KWAN HW (1) CHAN KH (1) TONG HK (1) LI MP (2) FUNG MY (3) MONTAYRE J (4) LIU F (4)
Affiliation :
(1) Department of Operating Theatre, Caritas Medical Centre (2) Department of Operating Theatre and Theatre Service Centre, Princess Margaret Hospital (3) Department of Operating Theatre Services and Theatre Sterile Supply Unit, Yan Chai Hospital (4) JBI Hong Kong Centre of Evidence-based Healthcare Excellence, School of Nursing, The Hong Kong Polytechnic University
Keyword 1: :
Surgical Plume
Keyword 2: :
Surgical Smoke
Keyword 3: :
Operating Theatre (OT)
Keyword 4: :
Occupational Safety and Health (OSH)
Introduction :
Surgical plume, generated by energy-based instruments such as electrocautery, poses significant inhalation risks to both patients and operating theatre (OT) staff. It contains a complex mixture of harmful constituents, including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), viable cellular material, and fine particulate matter. In particular, particulate matter with diameters less than 2.5 micrometers (PM2.5) has been shown to contribute to respiratory irritation, DNA damage, inflammatory responses, and increased long-term occupational health risks such as chronic lung disease and cancer. Previous studies have demonstrated that smoke evacuation devices (SEDs) are effective in reducing the intraoperative concentration of surgical plume and associated airborne hazards. However, evidence from in densely populated and high-volume healthcare systems like Hong Kong—remains limited, especially in Asian countries. This project collaborates with The School of Nursing at The Hong Kong Polytechnic University which has extensive experience in conducting evidence-based healthcare research, particularly in nursing-led clinical trials.
Objectives :
The study aims to assess whether using an electric scalpel equipped with a SED during total knee or hip replacement or open spine surgery can effectively reduce intraoperative PM2.5 exposure.
Methodology :
This study is a multi-center, open-label, parallel-group prospective randomized controlled trial with a 1:1 allocation ratio. The trial will be conducted in the three operating theatres of Kowloon West Cluster (KWC) for elective orthopedic operations including total knee replacement, total hip replacement, and open spinal surgeries. Block randomization will be applied using a computer-generated randomization sequence. Allocation concealment will be ensured using sealed opaque envelopes. The participants and data analysts will remain blinded to group allocation to reduce assessment bias. The surgical protocol will be standardized across all centers. The primary outcome is the intraoperative PM2.5 concentrations, measured using an air quality monitor placed close to the surgical site. The peak and average PM2.5 levels during the first 10 minutes of skin incision will be recorded and the 5 highest value will be used for analysis. Inclusion criteria: 1.Adults aged 18 years or older 2. elective total knee replacement, total hip replacement, or open spine surgery 3. general anesthesia or spinal anesthesia. Exclusion criteria: 1.Emergency surgeries 2.Patient refusal or unable to obtain consent 3.Surgeon refusal. Sample Size : 50. 32 in CMC, 13 in YCH, 5 at PMH. Methods of Data Analysis: Fisher’s exact test or the exact binomial test, while numerical variables will be evaluated using the Mann–Whitney U test. Statistical significance will be defined as a p-value less than 0.05. All data will be analyzed using SPSS software (version 29). Ethical Concern: The study has been approved by the HA Central IRB Committee before implementation.
Result & Outcome :
1. Comparison between the intervention and control groups demonstrated statistically significant differences in both average and peak PM2.5 levels. For average PM2.5, (0.19 ± 0.23 vs 26.78 ± 34.17, P< 0.001). For peak PM2.5 level, (0.26 ± 0.28 vs 71.71 ± 102.04, P=0.002). These findings indicate that the use of smoke evacuation systems (SESs) is associated with a significant reduction in PM2.5 exposure during surgical procedures.
2. Descriptive analysis showed that spine surgery had higher mean values for both average and peak PM2.5 compared to total knee and total hip replacement operation. This finding suggests that PM2.5 exposure may vary across surgical procedures, with a tendency toward higher levels in spine surgery; however, this trend was not statistically significant.
3. Comparison between the robotic knee and knee replacement groups showed no statistically significant differences in either average or peak PM2.5 levels.
