Nosocomial infection management measures in negative pressure isolation wards

Nosocomial infection management measures in negative pressure isolation wards

Essential Facilities for Infection Control in Healthcare Settings

Introduction

Negative pressure wards provide optimal conditions for isolating infectious sources and blocking airborne diseases. These specialized facilities minimize the spread of infectious diseases, protect healthcare workers from infection, and effectively prevent cross-infection between patients.

Key Benefits

Containment of airborne pathogens
Protection of medical staff
Prevention of cross-infection
Safe environment for high-risk procedures

Primary Applications

Respiratory disease isolation
Pandemic response units
Emergency treatment of unknown pathogens
High-risk procedure environments

What is a Negative Pressure Isolation Ward?

Negative pressure isolation wards are specialized hospital rooms designed to isolate patients with infectious diseases transmitted through the air. They utilize directional airflow to ensure air moves from clean areas to contaminated areas, with lower static air pressure than surrounding spaces to prevent pathogen spread.

Design Principle

air flows directionally from clean areas → semi-contaminated areas → contaminated areas

Ward pressure maintained lower than surrounding areas

air changes: 8-12 times per hour

Applications

Pneumonic plague
SARS and COVID-19
Tuberculosis
Measles
Influenza
Unknown pathogen emergencies

Negative pressure isolation ward

Design & Layout Requirements

Location Requirements

Minimum 20m distance from other buildings
Independent setup or at building ends
Positioned downwind of prevailing winds
Top floor preferred in high-rise buildings

Zone Requirements

Strict separation: clean, semi-contaminated, contaminated areas
Buffer zones between areas
Dual corridors: inner (staff), outer (patient)
Independent entrances/exits

Facility Requirements

Hand-washing Stations

With non-touch faucets

Shower Facilities

For decontamination

Double-door Pass-through

For safe transfer of items

Access Control

Prevent unauthorized entry

HVAC System Requirements

System Design

Independent systems for each functional zone
Fresh air mode or fan coil + fresh air
No shared central AC with other wards
Constant Air volume system (24/7 operation)

Filtration Requirements

Low-resistance high-efficiency filters
Air quality: ≤500cfu/m³ bacteria
Exhaust: ≥99.99% efficiency filters
Filter replacement schedule critical

Air Handling Specifications

Parameter	Requirement	Notes
Air Changes	8-12 times/hour	Ward area
Fresh Air Volume	≥40m³/h per person	Minimum requirement
Exhaust Speed	≤1.5m/s	At return outlets
Fresh Air Intake	≥3m above ground	≥1m above roof

Ward air conditioning and ventilation system

Pressure & Airflow Management

Pressure Gradient

Clean area > Semi-contaminated > Contaminated

Clean area: Positive pressure

Semi-contaminated: Transition

Contaminated: Negative pressure

Minimum pressure difference: ≥5Pa between zones

airflow design

Upper supply, lower side return
Directional flow: clean → contaminated
Main supply near staff position
Exhaust near patient bed
Avoid airflow between patient beds

Ventilation in ward

Operational Guidelines

Staff Procedures

Verify negative pressure before entry
Wear appropriate PPE:

Secondary protection: masks, gowns, gloves
Tertiary for aerosol procedures: respirators

Use hand-washing stations before/after
Avoid standing near exhaust vents

Facility Management

Keep doors/windows closed at all times
Maintain ≥0.9m clearance around beds
Single patient per room preferred
Restrict patient movement
Dedicated cleaning equipment
Strict medical waste protocols

Filter Maintenance Schedule

Filter Type	Maintenance Frequency	Notes
Pre-filter	Clean every 2 days	Replace every 1-2 months
medium filter	Check weekly	Replace every 3 months
Sub-hepa	Annual replacement	Replace if contaminated
hepa filter	Annual check	Replace if resistance >160Pa or after 3 years

Zone Definitions

Clean Area

Not contaminated by patient materials. Patients prohibited.

Includes: Staff rooms, locker rooms, storage, food prep

Semi-Contaminated Area

Potentially contaminated zone. Transition area.

Includes: Nurse stations, treatment rooms, equipment processing

Contaminated Area

Patient treatment zone. Contains infectious materials.

Includes: Patient rooms, waste areas, admission rooms

Buffer Room

A transitional space with doors on both sides between zones for staff preparation and decontamination.

This comprehensive guide to negative pressure isolation wards covers essential design requirements, operational protocols, and safety measures for effective infection control in healthcare settings.

Based on international standards and best practices for airborne infection isolation