The Effect of Plasma-air-filtration on the Incidence of Surgical Site Infections in Orthopaedic Surgery

Study Overview
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Brief Summary
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The study is a multicenter, double-blind, randomized, controlled trial conducted at six major university and teaching hospitals with a catchment population of approximately 2 million. In the current study it has been hypothesized that a non-invasive air cleaner utilizing a plasma chamber can significantly reduce the incidence of surgical site infections (SSIs).

Detailed Description
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Despite operating in clean theaters, surface sterilization, and antibiotics, surgical site infections (SSI) after orthopaedic surgery have an estimated incidence of 1-4%. This feared complication is associated with long-term antibiotics, repeated surgeries, prolonged hospital stays, economic burden and a poorer end result for individual patients. It is therefore of great importance to prevent SSI.While skin bacteria and contaminated surfaces have generally been claimed to be the main cause of infections, there are estimates that approximately 20% of hospital-acquired infections are air-transmitted, making this an interesting intervention target. Novaerus is an air-cleaner that sterilizes the air particles through a plasma chamber. Air in the operating theatre is pumped through the chamber (80-380 m3/Hr) and by using a small current it transforms the gas in the vicinity of the electrode into plasmaand eradicates any bacteria that pass through.The small size of the machine allows it to fit into any operating theater without interfering with existing equipment. This technology can reduce the number of colony forming units (CFU) when in hospital settings. In non-randomized settings it has been correlated to reduced respiratory infections, reduced personnel sick-leave, and absence of severe infectious outbreaks. Its effect has not been validated in randomized controlled trials. Both local and national registry data will be used according to availability.

Official Title
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The Effect of Air-filtration Through a Plasma Chamber on the Incidence of Surgical Site Infections in Orthopaedic Surgery: a Double-blind, Randomized, Controlled Trial

Conditions
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Orthopaedic Surgery (30 Minutes or Longer)

Intervention / Treatment
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* Device: Novaerus NV800 on
* Device: Novaerus NV800 off
* Device: Novaerus NV800 on or off


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: All patients that undergo a 30 minute or longer orthopaedic surgery Exclusion Criteria: The following surgeries will be excluded: already infected surgical site, defined as: ICD-codes indicating infection, Open fractures, Traumatic wounds, Vacuum assisted wound therapy Patients that have had antibiotics prescribed 2 weeks or less prior to surgery Patients that have actively marked their hospital charts with an added privacy notice
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Exposed patients: Plasma-filter on<br>Those operated with Novaerus NV800 on for at least 2 Days prior to index surgery. This Group will also in the analysis be sub-grouped according to measurements prior to study start into: regular operating theater ultra-Clean operating theaters | Device: Novaerus NV800 on<br>* The air-cleaner sterilizes the air particles through a plasma chamber. Air in the operating theatre is pumped through the chamber (80 - 380 m3/Hr) and by using a small current it transforms the gas in the vicinity of the electrode into plasma and eradicates any bacteria that pass through. The air-cleaner has to have been turned on for at least 2 days prior to the surgical intervention.<br>|
| Experimental: Unexposed patients: Plasma-filter off<br>Those with Novaerus NV800 off for at least 2 Days prior to index surgery | Device: Novaerus NV800 off<br>* The machine decribed above is running but the plasma filter chamber isn't active, i.e. the placebo group.<br>|
| Experimental: Mixed patients: Plasma-filter on or off<br>Those receiving multiple surgeries in different theaters with Novaerus NV800 on or off status will belong to a mixed Group. | Device: Novaerus NV800 on or off<br>* Patients with multiple surgeries that have been operated during both periods when the apparatus has been on and off will belong to this mixed group.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of patients with surgical site infection after orthopaedic surgery, defined as any of the following: using antibiotics targeting Staphylococcus aureus, having ICD-codes or surgery codes indicating postoperative infection. | All definitions are merged into one binary outcome measure as any(No. > 0) | Within 12 weeks after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patients using any antibiotics after surgery | This is identified either via hospital information system or from the national drug registry. Usage is defined as withdrawal or prescription of a drug with ATC code within the J01 group. | Two treatment days or more during the first 30 postoperative days | 
| Number of days with antibiotics | This is identified either via hospital information system or from the national drug registry. Usage is defined as withdrawal or prescription of a drug with ATC code within the J01 group. Number of days is deduced from the prescribed dosage or if not present the average daily dosage for that particular drug is used. | During the first 30 postoperative days | 
| Patients using any antibiotics after surgery | This is identified either via hospital information system or from the national drug registry. Usage is defined as withdrawal or prescription of a drug with ATC code within the J01 group. | Two treatment days or more during the first 90 postoperative days | 
| Number of days with antibiotics | This is identified either via hospital information system or from the national drug registry. Usage is defined as withdrawal or prescription of a drug with ATC code within the J01 group. Number of days is deduced from the prescribed dosage or if not present the average daily dosage for that particular drug is used. | Two treatment days or more during the first 90 postoperative days | 
| Death | Any cause of death | during the first 2 postoperative years |