Indmedica Home | About Indmedica | Medical Jobs | Advertise On Indmedica
Search Indmedica Web
Indmedica - India's premier medical portal

Journal of the Academy of Hospital Administration

Structural Requirements for Infection Control in Hospitals

Author(s): S K M Rao

Vol. 16, No. 2 (2004-07 - 2004-12)

Key Words:

Infection control, design of hospital, structural requirements of infections, air lock, isolation room

Key Messages:

  • Scientific design of hospital plays important role in infection control.
  • Design of wards, isolation room,ICU,OT should be as per correct infection control norms.
  • Role of air lock, ante room, ventilation standards crucial in airborne transmission of infections.

Introduction

Patient care is provided in facilities which range from highly equipped clinics, and technologically advanced teaching hospitals to frontline primary health centers with only basic facilities. Despite progress in public health and hospital care, infections continue to develop in hospitalized patients, and may also affect staff. Many factors promote infection among hospitalized patients; decreased immunity among patients; the increasing variety of medical procedures and invasive techniques and the environmental transmission of drug resistant bacteria among crowded hospital populations, where poor infection control practices may facilitate transmission. A good hospital design therefore needs to consider the separation of dirty and clean areas, adequate ventilation standards, storage facilities and design of patient accommodation areas including adequate number of wash hand basins and single bed facilities.1

The role of infection control in the design of facilities has become increasingly visible as communicable diseases like tuberculosis and multi drug resistant organisms have caught the attention of the media affecting both consumer awareness and regulatory agencies responsible for environmental health and sanitation.2

The hospital environment plays an important part in the development of infections. Whereas the hospital may not have such control over the host factors and agents, the hospital certainly is responsible for the environment that surrounds the patient. By controlling and adequate sanitizing the environment of the host, the hospital authorities can markedly reduce the incidence of hospital acquired infections.3

Most of the hospitals in developing countries are not scientifically designed. Physical facilities are most inadequate and. wards are overcrowded. There are hardly any separate arrangements for septic and clean cases specially in surgical and maternity wards. Patient placement is generally found to be faulty. Requirements of air Conditioning and ventilation are not met properly, thus increasing the risk of infection transmission. Overcrowding in nurseries and ward units promotes risk of cross infection.

General design consideration

The foresight of a hospital planner lies in achieving a good hospital architectural design for better infection control. At the planning stage itself certain criteria and principals should be followed.4,5

  1. The design should support functional segregation of OPD, in patient units, diagnostic services and supportive services so that mixing of patient flow is avoided.
  2. Separation of critical areas like OT, ICU from general traffic and avoidance of air movement from areas like laboratories and infectious diseases wards towards critical areas.
  3. The design should support concept of zoning and ventilation standards in acute care areas.
  4. The clean corridor and dirty corridor should not be adjacent and they should facilitate traffic flow of clean and dirty items separately.
  5. Isolation wards for infectious cases to be kept out of routine circulation.
  6. Adequate number of wash hand basins should be provided within the patient care areas and nursing stations with a view to facilitate hand washing practice.
  7. Separate arrangements for garbage and infectious waste removal from wards and departments in the form of separate staircases and lifts.
  8. Construction of isolation rooms within the wards including ICU and acute care areas.
  9. Provision of airlock and anteroom before entering into critical care areas.

It may not be possible to discuss structural requirements for all the areas in a superspeciality hospital, however, certain important areas common to all hospitals have been deliberated.

Design of Ward Units

Control of infections in wards not only requires application of the principles of a sepsis and hygiene but also considerations of design, equipment and ventilation of the ward. Hand washing has been recommended as single most important practice to control Hospital Acquired Infection. The number of sinks and their placement should be thoughtfully planned to encourage Health Care worker to practice hand washing before and after every patient care activity. Though nursing of each patient separately is ideal, at least 2-4 single rooms for a 30 bed unit are sufficient. Moreover, overcrowding in pavilion wards should be avoided by keeping centers of beds at least 8 feet apart.1

A general ward can be planned based on bed strength ranging from 24-32 beds on Rigs pattern consisting of 2 single bed rooms, 2 four bedded rooms and rest 6 bedded rooms. One wash hand basin each for these rooms averaging to one WHB per six beds should be provisioned. Floor space area per bed should be kept to 7 sqm excluding central corridor of 2.4 meters. Single bed rooms should be given 14 sqm and distance between centers of beds in 6 bedded rooms should not be less than 2.5 meters.

It is recommended that whenever possible, a patient known or suspected to harbour transmissible microorganisms should be placed in a single room with hand washing and toilet facilities. A single room helps prevent direct or indirect contact transmission or droplet transmission. A checklist for planning of isolation rooms in wards or as a separate ward is tabulated at table I. 4

One to two standard isolation rooms per ward unit should be planned throughout the hospital with wash hand basin in room, shower, toilet and wash hand basin in bathroom. Door with self closing device and a normal window AC to be provisioned for these rooms.

Dirty utility and soiled linen room of size 10.5 sqm per ward with facilities for bed pan sink, Macintosh sink and slop sink is required in each ward. Water supply of hot and cold water should be catered and in addition janitors closet of 3.5 sqm for keeping mops and detergents should be provisioned in each ward.

Planning of ICU

A number of professional and scientific bodies in the UK and USA have published guidelines on the design and layout of ICUs. All emphasize the importance of adequate isolation facilities at least one cubicle per eight beds, sufficient space around each bed at least 20 sqm, hand wash basins between every other bed, Ventilation including positive and negative pressure ventilation for high risk patients and sufficient storage and utility space. Floors and walls should be easily cleanable and non porous. Dirty utility should have separate stand / shelf per bed . Bedpans, urinals to be kept dry and hand wash solutions / basins at each bedside.

American Institute of Architects (AIA) guidelines for new constructions recommends the minimum number of hand washing facilities for patients as one in the toilet room plus having a sink in patients room will support Infection Control practices. Small cup sinks that challenge proper hand washing should be avoided. Improper placement of sinks can add to the environmental reservoir of contaminants. Sinks need to be convenient and accessible but nearby surfaces should also be nonporous to resist fungal growth. Space beneath the wash hand basins should not be used as storage place for fear of leaks and proximity to sanitary sewer connections.6

ICU of eight beds with 2 additional isolation cubicles is ideal for general multispeciality hospital. Each bed should have 14 sqm floor space with adequate place for Bed head unit and separate sterile supplies.. Each isolation cubicle inside ICU is planned with self closing door and airlock. Air lock is supposed to have following functions :

  1. They provide a barrier against loss of pressurization and against entry / exit of contaminated air into / out of the isolation room.
  2. They provide a controlled environment in which protective garments can be donned without contamination before entry into the room.
  3. They also provide a Physical and Psychological barrier to control behaviour of staff in adopting infection control practices.

ICU should be planned with 10 air changes per hour as per minimum ASHRAE standards. Positive pressure gradient of 15 pa is recommended between isolation cubicle and main ICU. International recommendations for room pressures are as per table 2. One hand washing station with hands free operable controls should be available in between two beds or else stands for holding hand wash solutions for each bed be planned to promote hand washing practices. A large spacious dirty utility is required in ICU where each patient’s bedpan, urinal etc, can be stored after disinfection.

Automatic air curtains are desirable at the air lock and entry into patient care area in ICU, Acute care wards, OT sterile area, Neonatal ICU, delivery suites. They have the capability of keeping outside environment separate from inside environment in critical care areas.

Planning of Operation Theatre

There is a general agreement that the factors affecting occurrence of infection in operation theatre are :

  1. Type of surgery
  2. Quality of air provided
  3. Rate of air exchange
  4. Number of persons present in OT
  5. Level of compliance with infection control practices
  6. Quality of staff clothing and quality of cleaning process

British Medical Council has recommended the following basic requirements for control of infections in OT.

  1. Separation from general traffic and air movement of hospital
  2. Zoning i.e. sequence of increasingly clean zones from the entrance to the operating area with the aim of reaching absolute asepsis at operating site.
  3. Easy movement of staff from one clean area to another without passing through dirty areas.
  4. Removal of dirty materials from the suite without passing thorough clean areas.

Objectives of ventilation system in OT are recommended to be as follows :

  1. To prevent less clean air from neighboring rooms entering the OT by using different air pressures.
  2. To create an air flow pattern that carries contaminated air away from the operating table
  3. To provide a comfortable environment for the operating team and patients with controlled temperature, humidity and ventilation.

The following will achieve all the objectives for operation theatre complex of the hospital7:

  1. Sterile Zone
    1. Temp : 23 oC+ 3 0C
    2. Relative humidity : 40 % to 60 %
    3. Fresh Air allowance : 10 per hour with Total air changes 25 per hour. Total fresh air with no recirculation in super speciality surgery.
    4. Air filters : Through HEPA filters with filtration level up to 0.3 microns and 99.97 % efficiency with pre filters in the system(proven helpful in superspeciality OT’s).
    5. Positive pressure = 25 Pa
  2. Other areas : Fresh air changes minimum 5 per hour and total 15 per hour. HDPE washable filters with filtration level up to 5 microns.
  3. One separate dedicated AHU designed to maintain Positive pressure gradient so as to ensure flow of air from sterile to clean and protective zone. Aluminum air conditioning ducts with differential pressure gauge / manometer across HEPA filters so as to detect clogging or reduced flow of air.
  4. No shelves will be provided inside OT.
  5. Purified water will be supplied for scrub with steel scrub and facility of dispensing of hand wash solution as well as water through foot control
  6. Recommended floor surface is Epoxy resin flooring, which has been found to be seamless, scratch proof, hard enough for wheeled trolleys, stain free and antistatic. Other surfaces like vitrified tiles have been found to be equally effective
  7. Laminar flow which is a low turbulence downward displacement air flow towards the operation zone through stainless steel perforated grills is recommended
  8. Air curtains at the entry of sterile zone should been planned.
  9. Drains, sewerage pipes and water line should be avoided at least near and above operation theatre sterile zones. CSSD

The CSSD provides centralized sterilization of the equipment, sets, instruments and linen which are used in almost all departments of the hospital. Major consumers of this facility are operation theatres, delivery suites, ICU, NICU etc. There should not be any mixing of sterile and contaminated goods in the department.

Reception of contaminated articles, checking, sorting, grading and cleaning areas with two steel sinks, drain board with swan neck fittings and work bench, and autoclave room of 21 sqm with opening into un sterile area and exit into sterile area is sufficient for a general hospital. Sterile storage with ample shelving and issue counter is required. Entry of staff bringing un sterile items and issue of sterile items should be preferably from different corridors.

Laundry

This can be done manually by dhobies or mechanically by washing machines, though laundering is not sterilisation process, it should remove evidence of previous use including microorganisms. The number of microorganisms should reduce from 10-20 org/square cm to approx one per sqm or less. Contaminated linen is also one of the major source of hospital infection. Drying of linen in open areas on grass should be avoided as they get heavily contaminated. Different processes in the mechanised laundry, i.e. washing, mechanised drying, calendering at high temperature and steam pressing results in thermal disinfection of linen and considerable reduction in bacterial count of the linen.

Considering the following factors in addition to mentioned above a mechanical laundry is required in the hospital:

  1. Minimisation of loss and damage to the linen
  2. Safe handling of soiled and infected linen
  3. Complete control of washing formula
  4. Assured regular supply notwithstanding change of season.

Dietary Services

High standards of hygiene are particularly important in dietary services and designing of facility should take into consideration this factor. Proper food storage, adequate refrigeration facilities, separation of food and non food items, easily washable and clean surfaces in cooking and preparation areas and provisioning of hand washing facilities for dietary staff members and garbage holding transfer and disposal are some of the physical facilities requirement in dietary services.

TABLE - I: Isolation Room Checklist

  Class ‘S’ * Class ‘N’ * Class ‘P’ *
Hand wash basin in room Yes Yes Yes
Ensuite Bathroom (Shower, toilet, WHB) Yes Yes Yes
Poor on room with door closer Yes Yes Yes
Airlock - Yes Optional
Sealed room, door grills for controlled airflow - Yes Yes
Pan sanitiser (near room) Optional Optional Optional Independent exhaust - Yes -
Independent exhaust - yes -
HEPA filters on supply - - Yes
Air changes/hour - 6-12 6-12

S = Standard Isolation: For patients who require contact or droplet isolation
N= Negative Isolation: For patients who require air borne droplet nuclei isolation e.g. Tuberculosis
P = Positive Isolation : For patients who are profoundly immunocompromised e.g. transplant and on immunosuppressive treatment.

Table - II: Recommended Isolation Room Pressures

Type of Isolation Room Ensuite Airlock
Class ‘N’ -30 pa - 15 Pa -15 Pa
Class ‘P’ + 30 Pa + 15 Pa +15 Pa

References

  1. Aylifle GAJ, Lowbury E JL, Geddes AM, Williams JD. Control of Hospital infection - a practical hand book. Fourth edition, London I Chapman and Hall Medical, 1995, 76-79.
  2. Bartley JM. The role of infection control during construction in health care facilities. American Journal of Infection control Vol 28 No.2.April 2000. 156-161.
  3. Surveillance, Prevention and Control of Infection, Comprehensive Accreditation Manual Volume 5. Joint Commission of Accreditation for Hospital Organisations, USA Nov 2000.2-6.
  4. Center for Disease Control and Prevention. Recommendations for the Prevention of Hospital acquired Infection AM J Infect control 1996 : 22 : 267-92.
  5. Caster CD, Barr BA : Infection control issue in construction and renovation : Infection control and Hospital Epidemiology 18 (8) : 587-96, 1997.
  6. Health Care facilities. In : American society of Heating, Refrigeration and air conditioning Engineers, ASHRAE Hand book - HVAC applications. Atlanta : 1999. 7.1 - 7.1.2.

* Officer Incharge Hospital Projects, Office of DGMS (Army) L Block Army HQ New Delhi

Access free medical resources from Wiley-Blackwell now!

About Indmedica - Conditions of Usage - Advertise On Indmedica - Contact Us

Copyright © 2005 Indmedica