Airborne Infectious Disease Management: Methods For .

Airborne InfectiousDisease ManagementMethods for TemporaryNegative Pressure IsolationMinnesota Department of HealthOffice of Emergency PreparednessHealthcare Systems Preparedness Program

Airborne InfectiousDisease ManagementMethods for TemporaryNegative Pressure IsolationThis guide has been produced by:Office of Emergency PreparednessHealthcare Systems Preparedness Program

AcknowledgementsThis user guide has been written byThe authors gratefully acknowledge thethe Minnesota Department of HealthMinnesota Emergency Readinessin conjunction with the University ofEducation and Training (MERET) at theMinnesota to assist hospital personnelUniversity of Minnesota Centers forin the management of airbornePublic Health Education and Outreachinfection isolation.and the following individuals for theirparticipation, assistance, and supportAirborne InfectiousDisease ManagementMethods for TemporaryNegative Pressure IsolationAUTHORS:of this project:Jeanne AndersonInfection Control PractitionerOffice of Emergency PreparednessMinnesota Department of HealthKeith CarlsonDirector of Facilities ManagementMercy Hospital and Health Care CenterMoose Lake, MNAndrew GeeslinEngineering/Infection Control InternUniversity of MinnesotaGary DavisPlant EngineerLakeWood Health CenterBaudette, MNAndrew StreifelHospital Environmental Health SpecialistEnvironmental Health and SafetyUniversity of MinnesotaPete SwansonFacility Services ManagerPipestone County Medical CenterPipestone, MNFor further Information, please contact:Office of Emergency PreparednessMinnesota Department of Health625 Robert Street NorthP.O. Box 64975St. Paul, MN 55164-0975The following individuals are gratefullyMinnesota Department of Healthacknowledged for their invaluabledoes not endorse particular brands amongsuggestions:competing products. Examples shownin these materials are for illustration only.Phone: (651) 201-5701Fax: (651) 201-5720All material in this document is in the publicdomain and may be used and reprintedThis user guide is available on theMinnesota Department of Health Web pp/isolation.htmlwithout special permission.Judene BartleyVice PresidentEpidemiology Consulting Services Inc.Beverly Hills, MIRick HermansSenior Project ManagerCenter for Energy and EnvironmentMinneapolis, MNCurtain TNPI photographs courtesyof Ken Meade, Research MechanicalEngineer, NIOSH/CDC, USPHSMERET photos providedby Paul Bernhardt

AIRBORNE INFECTIOUS DISEASE MANAGEMENT PREPARED BY THE MINNESOTA DEPARTMENT OF oomTNPITemporary NegativePressure IsolationEnvironmentalcontrolsPrinciples of airborneinfectious diseasemanagement37201613532Hospital preparedness forIntroductionbioterrorism and other public healthemergencies such as emerging airborneinfectious diseases requires strategicplanning to ensure that all componentsof respiratory protection programs,including environmental controls,are in place for airborne infectionisolation rooms (AIIRs). Hospitalshave insufficient facilities to provideairborne infection isolation for largenumbers of patients with airborneinfectious diseases presenting ina short time period.1, 2 However, AIIRshave been increased recently, due torequirements of National BioterrorismHospital Preparedness Program.3Introduction1to other patients and health careworkers.4 Heating, ventilation,and air conditioning (HVAC)expertise is essential for properenvironmental management whenplanning control of airborne infectiousdisease outbreaks (natural orintentional). Design manuals andguidelines provide direction forinfectious disease management.5-11Refer to Appendix A, “2006 AIACriteria” on page 21.Without adequate environmentalcontrols, patients with airborneinfectious diseases will pose a riskThis guide will assist health care facilityplant maintenance and engineeringstaff, in coordination with infectioncontrol professionals, to prepare fora natural or terroristic event, involvingan infectious agent transmitted byairborne droplet nuclei. Examplesof such agents include measles,varicella, and tuberculosis.5Audience for this GuidePurpose of this GuideGoal of this GuideThe intended audience for thisguideline includes health care: Provide guidance on environmentalA timely response is crucial foridentification and containmentof potentially infectious patients.The goal is for facilities to developa 12-hour response to implementcontainment measures. Temporarynegative pressure isolation methodsare a safe alternative for hospitalsthat lack engineered AIIRs.These can be utilized in facilities tomeet increased surge capacity forpatient isolation. TNPI should alsobe used during hospital constructionprojects to reduce risks associatedwith airborne infectious diseases. facility engineering and maintenance infection control environmental health and safety management personnelcontrols for airborne infectiousdisease management Provide a general guide fortemporary setup, installation,and operation of portable HEPAmachines when used to createnegative pressure in a hospitalroom/area Provide instruction on the use of:Pressure gaugesParticle counters Outline of preventativemaintenance schedule forHVAC equipment related to AIIRThese temporary measures shouldbe incorporated into the facility’sinfection control and emergencyresponse plans.

AIRBORNE INFECTIOUS DISEASE nteroomTNPITemporary NegativePressure IsolationEnvironmentalcontrols3720161353 PREPARED BY THE MINNESOTA DEPARTMENT OF HEALTHPrinciplesof irborne infection isolationis based on the following hierarchyof control measures.Principles ofairborne infectiousdisease managementAdministrative (work practice) controlsEnvironmental controlsPersonal protective equipment (PPE)These measures are intended toreduce the risk for exposure toairborne infectious disease agentsby uninfected persons. AIIRs andhospital systems in general mustbe monitored to provide continualprotective measures. Refer toAppendixes B and C, AIIR andHVAC System MaintenanceSchedules, on pages 22 and 23.AdministrativeEnvironmentalPersonal(work practice) controlscontrolsprotective equipment (PPE) Managerial measures that reducethe risk for exposure to personswho might have an airborneinfectious disease. Physical or mechanical measures Equipment worn by health care Work practice controls includeusing infection control precautionswhile performing aerosol-generatingprocedures, closing doors to AIIRs,hand hygiene, and signage.EXAMPLESwritten policies andprotocols to ensurethe rapid identification,isolation, diagnosticevaluation, andtreatment of personslikely to have anairborne infectiousdisease(as opposed to administrativeworkers and others to reducecontrol measures) used to reduceexposure to communicablethe risk for transmission of airbornediseases.infectious nglovesultraviolet germicidalirradiationmasksAIIRseye protectionlocal exhaustventilation devicesrespirators

AIRBORNE INFECTIOUS DISEASE nteroomTNPITemporary NegativePressure Isolation372016135Environmentalcontrols PREPARED BY THE MINNESOTA DEPARTMENT OF HEALTHPrinciples of airborneinfectious diseasemanagementIntroduction213 A difference in pressureEnvironmentalcontrolsThis user guide will focus on theenvironmental controls necessaryfor airborne infection isolation.The ventilation parameters essentialfor airborne infection isolationrooms/areas include: Pressure management forappropriate airflow direction; Room air changes fordilution ventilation; and Filtration to removeinfectious particles.Pressure IZEDFIGURE 1Illustrations used to identifyNegatively (top) and Positively (bottom)pressurized air space.For the purposes of this guide,pressure refers to the differentialpressure between two spaces(FIGURE 1).In health care settings, the two spacesare typically the isolation room and thecorridor. For AIIR, the room shouldbe negatively pressurized in relationto the corridor. This helps to preventinfectious particles from escaping theroom envelope.If an anteroom is present between theAIIR and the corridor, the AIIR may benegatively or positively pressurized tothe anteroom. However, if the AIIR ispositively pressurized to the anteroom,the anteroom must be negativelypressurized to the corridor.causes movement of air from areasat higher pressure to those at lowerpressure. The greater the pressuredifference, the greater the resultingair velocity. The movement of air isused to help provide containment ofinfectious particles by providing cleanto dirty airflow. Refer to Appendix D,“Using a Pressure Gauge toMeasure Relative PressurizationBetween Two Spaces” on page 24for instructions on using a pressuregauge to determine differentialpressure. The differential pressure orpressure offset is established bymechanically adjusting the supplyand exhaust air. For a negativepressure room, the sum of themechanically exhausted air mustexceed the sum of the mechanicallysupplied air. This offset forces air toenter the room under the door andthrough other leakages and preventsinfectious particles from escaping.9 In order to maintain consistentoffset airflow, the difference betweenexhaust and supply should createa pressure differential of about0.01 inch water gauge (in. w.g.)or 2.5 Pascals (Pa).9 Pressure inthis application is used to induceairflow from adjacent spaces intothe isolation room.

AIRBORNE INFECTIOUS DISEASE nteroomTNPITemporary NegativePressure Isolation372016135Dilution ventilationEnvironmentalcontrolsDilation ventilationFiltrationFiltrationMechanical ventilation is usedto exchange the air in a space.The time required for removinga given percentage of airborneparticles from a room or spacedepends on the number ofair changes per hour (ACH),location of the ventilationinlet and outlet, and the physicalconfiguration of the room or space(FIGURE 2).Refer to Appendix E, “Usinga HEPA Filter for DilutionVentilation” on page 26. PREPARED BY THE MINNESOTA DEPARTMENT OF HEALTHPrinciples of airborneinfectious diseasemanagementIntroduction214When used correctly, portable HEPAfilters prove to be an effective methodfor achieving an airborne isolationenvironment.12 When properly installedand maintained, filters for clinicalspaces should be able to remove atleast 90% of particles (0.5 micronsin size and larger) 9 from outside andinside air.For the purposes of this guide,filtration refers to the process ofpassing air through a filter. Hospitalbuildings have some of the highestfiltration requirements. Without filtration,particle concentrations accumulate inindoor environments. This can causetoxic effects even in healthy people.For evaluation of hospital HVAC systemsand HEPA filters refer to Appendix G,“Using a Particle Counter to AssessIndoor Air Quality and Filter Efficiency”on page 29.Filtration reduces the risk fortransmitting airborne infectious agents.Depending upon their size, particlesmay be deposited in the upperrespiratory tract or the lower respiratorytract of humans. Particles can also bedeposited in open wounds duringdressing changes or invasiveprocedures. See Appendix F,“Microorganisms Associated withAirborne Transmission” on page 28.For information on filter selectionand performance, see Appendix H,“Data Interpretation” on page 34.See Appendix I, “Sample Log forMeasuring Particle Counts” on page 36. FIGURE 2: ACH AND TIME REQUIRED FOR REMOVAL 1591828207142150368ACHModified from Table B.1, CDC Guidelines forEnvironmental Infection Control in Health-Care Facilities,2003.5M INUTESTime (minutes) required for removal of 90%, 99%, and 99.9% of 2011010090807060504030201090% EFFICIENCY99% EFFICIENCY99.9% EFFICIENCY24681012152050AIR CHANGES PER HOUR (ACH)Perfect mixing of air is assumed. For rooms with stagnant air spaces, the time required may be much longerthan shown. This is intended only as an approximation and is for ideal ventilation configurations.