Infection control, design of hospital, structural requirements of infections, air lock, isolation room
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.
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
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.
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.
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 :
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.
There is a general agreement that the factors affecting occurrence of infection in operation theatre are :
British Medical Council has recommended the following basic requirements for control of infections in OT.
Objectives of ventilation system in OT are recommended to be as follows :
The following will achieve all the objectives for operation theatre complex of the hospital7:
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.
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:
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.
|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|
|Sealed room, door grills for controlled airflow||-||Yes||Yes|
|Pan sanitiser (near room) Optional Optional Optional Independent exhaust||-||Yes||-|
|HEPA filters on supply||-||-||Yes|
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.
|Type of Isolation||Room||Ensuite||Airlock|
|Class ‘N’||-30 pa||- 15 Pa||-15 Pa|
|Class ‘P’||+ 30 Pa||+ 15 Pa||+15 Pa|
* Officer Incharge Hospital Projects, Office of DGMS (Army) L Block Army HQ New Delhi