|Year : 2020 | Volume
| Issue : 2 | Page : 216-220
Hospital oxygen supply: A survey of disaster preparedness of Indian hospitals
Cherish Paul, John Paul, Akhil Babu
Department of Anaesthesia and Critical Care, Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India
|Date of Submission||19-Apr-2020|
|Date of Decision||15-May-2020|
|Date of Acceptance||01-Jun-2020|
|Date of Web Publication||07-Jul-2020|
Dr. John Paul
Department of Anaesthesia and Critical Care, Jubilee Mission Medical College and Research Institute, Thrissur - 680 005, Kerala
Source of Support: None, Conflict of Interest: None
Background: Uninterrupted oxygen supply is an essential hospital facility. Careful planning is needed to prevent major mishaps in case of failure. We undertook a survey to assess vulnerability of oxygen supply systems to disasters. Methodology: Hospitals in South India were stratified and randomized based on their bed strength. A structured telephonic interview was done to the managers of engineering departments in these hospitals. The questionnaire included type of oxygen source, location, changeover mechanism, and alarm systems. Results: Of the 30 hospitals randomized, adequate information was obtained from 25 hospitals. The primary source of the supply was cylinder manifolds in 48%, liquid oxygen in 40%, and concentrators in 12% hospitals. A reserve source of oxygen supply was available in 64% hospitals; 44% with cylinders, and 20% with liquid oxygen. Only 52% of the hospitals had a reserve supply in a different location from the primary. Changing the source of supply was manual in 44% of hospitals and 20% had an automatic change over system installed. There were effective zonal and central alarms in only 12% of hospitals. Conclusion: Most of the hospitals rely on a single pipeline from a single location inviting mishaps during the disasters. Contingency planning to reduce the risk of an uninterrupted supply should involve automatic changeover systems to a backup source with physically separated feed lines. Primary, secondary, and reserve supply could involve the use of liquid oxygen, oxygen concentrators, or cylinder manifold systems in various combinations depending on the size of hospital, proximity to a liquid oxygen plant and risk.
Keywords: Disaster preparedness, liquid oxygen, oxygen concentrator, oxygen supply
|How to cite this article:|
Paul C, Paul J, Babu A. Hospital oxygen supply: A survey of disaster preparedness of Indian hospitals. Indian J Respir Care 2020;9:216-20
|How to cite this URL:|
Paul C, Paul J, Babu A. Hospital oxygen supply: A survey of disaster preparedness of Indian hospitals. Indian J Respir Care [serial online] 2020 [cited 2021 Jun 19];9:216-20. Available from: http://www.ijrc.in/text.asp?2020/9/2/216/289087
| Introduction|| |
In the present era, there is no dearth of literature on the various advances in the medical field. However, despite all these advances, one must have a sagacious outlook toward the safety of water, oxygen, and electricity supply which are the lifelines of any hospital. A regular protocol is needed to ensure the safety of supply of these vital components.
A preliminary look at the oxygen supply at our hospital showed many shortcomings. On the basis of this, a questionnaire was framed aiming to answer the crucial question of whether our oxygen supply system is safe and whether it can it survive disasters. To assess disaster preparedness, an in depth understanding of the working principles of our gas supply was required. An earlier survey in North America showed that anesthesiologists grossly lacked knowledge of the gas supply system in their respective hospitals. Those who were aware were mainly so after a mishap had happened in their work environment. Oxygen supply at any hospital encompasses three components: primary, secondary, and a reserve component.
The main oxygen source could be a cylinder manifold system, liquid oxygen system, or oxygen concentrator system.
This is the alternative source in case of failure of the primary system or during its repair. The secondary supply ensures the provision of about 4 h of uninterrupted oxygen. This is usually a manual cylinder manifold system or can be the second vessel of liquid oxygen in case the primary is liquid oxygen.
Reserve supply (third source of oxygen supply)
This is usually an automated cylinder manifold system to support high-dependency areas or the whole hospital.
Cylinder manifold should not be placed at the same site as that of liquid oxygen or oxygen concentrator. It is beneficial to have the reserve supply of oxygen at a different location than the primary supply, even if both the supplies are cylinder manifolds. Such a plan would mitigate the shortage of oxygen supply during an eventuality.
| Methodology|| |
Approval for this study was obtained from the institutional ethics committee. Initially, a pilot study was conducted by preparing and circulating a questionnaire on the hospital oxygen supply at an anesthesiology conference. In the pilot study, the awareness of 40 anesthesiologists was assessed. A few lacunae were found in the knowledge and understanding of oxygen supply and its safety measures among anesthesiologists. It was considered as technical knowledge rather than an extremely critical clinical issue.
Amendments were made to the questionnaire after the pilot study. In the final questionnaire, all attempts were made to make the data as informative as possible. Telephonic conversations with the hospital staff were made for any pertinent issues that needed to be clarified. Anonymity was assured to ensure candid reply to the questionnaire. In a similar study by Stoller et al., many hospitals were lacking the infrastructure necessary to avoid mishaps during maintenance works or accidents.
The hospitals were divided according to the number of inpatient beds as Group A with 100–500 beds, Group B with 501–1000 beds, and Group C with more than 1000 beds. A stratified random sampling was done and 10 hospitals were selected from each group.
Hospitals with <100 beds were excluded by the following calculation. At any point of time, approximately 25% patients admitted to a hospital may require about 6 L of oxygen per minute. Thus, even if exclude the areas of high oxygen requirements such as operation theaters, intensive care units, emergency medicine areas, the oxygen requirement of a 100 bedded hospital is about 150 L/min or 2.16 lakh L/day.
The usual manifold cylinder is J type with a capacity of 6800 L of oxygen. A hospital should have a primary supply oxygen to last for a minimum of 4 days, and this means around nine lakh L. For ensuring this, a hospital will have to store 130 “J” type cylinders, which means its storage and logistics would be stretched.
| Results|| |
Out of the 30 hospitals with which interview were attempted, adequate data could be collected from 25 hospitals. This involved 10 in Group A (up to 500 beds), 8 in Group B (501–100 beds), and 7 in Group C (more than 1000 beds).
Primary source of oxygen supply was cylinder manifold in 48% hospitals, liquid oxygen in 40% hospitals, and concentrator in 12% of the hospitals [Figure 1].
A total of 64% hospitals had a reserve source of oxygen supply, 44% with cylinders as the reserve source, and 20% with liquid oxygen [Figure 2].
Only 12% hospitals had a secondary supply of oxygen which served as emergency backup used only during failures and repairs, but only 4% had all three sources of oxygen supply.
Only 52% of the hospitals had a reserve oxygen supply at a different location than that of the primary. In 12% of the hospitals, cylinder manifolds were either sited near liquid oxygen source or oxygen concentrators.
Changing the source of oxygen supply was manual in 44% of hospitals, whereas 20% had an automatic change over system installed. There were effective zonal and central alarms in only 12% of the hospitals. Twenty-eight percent did not have any alarm systems installed in case of mishap, and 60% had either one of central or zonal alarm systems [Figure 3].
| Discussion|| |
The average daily use of oxygen as well as the peak daily requirement in the hospital should be calculated. A logbook to this effect should be maintained. Depending on this, the type of oxygen supply systems which should be installed can be determined.
These are the most common source of oxygen supply being readily available even in small towns. Usually, it is the type “J” cylinder which can hold up to 6800 L of oxygen. Adequate access to the storage area should be provided for gas cylinder delivery vehicles. A provision of raised level loading bay to reduce cylinder handling hazards could be considered. This could also be an advantage in natural disasters such as floods.
The cylinder manifold is being used in almost all hospitals either as a primary or a reserve source. In any given scenario, two banks, each consisting of 5–20 cylinders are commonly used as the primary source. Banks should meet the requirement for 4 days and should ensure reserve supply for at least 3 days. This calculation excluded the Type E cylinders on anesthetic machines and the Type F cylinders used for the transfer of patients.
[Table 1] shows common oxygen cylinder types used in hospitals.
An oxygen concentrator operates on the principle of adsorbing under pressure, gases other than oxygen in the atmosphere onto the surface of an adsorbent material, termed a zeolite (aluminum silicate). After adsorption, those gases except oxygen are vented out. This process called, fractional distillation, ensures that only oxygen is the primary gas remaining, which is then collected in a storage tank. The process is capable of producing oxygen concentrations of about 95%, the remainder consisting of argon with a small percentage of nitrogen.
Being self-sufficient in oxygen production with only electricity required for working is its biggest advantage. This makes it a good cause for installing such a unit in hospitals; however, big or small the size may be. No logistics are involved if concentrator is used as the source of oxygen. This has made it popular as a source of oxygen in African countries where road access is difficult. Canadian hospitals have been using these for the past four decades.
Pressure swing adsorber system can supply an oxygen concentration ranging from 93% to 97%, monitored by a paramagnetic oxygen analyzer. No serious aspects preclude the use of this oxygen from a medical point of view. The adjustments required when calibrating ventilators and other machines have been described.
Even though the technology has been around for a substantial period of time, it is getting popular in hospitals only now, with about 12% of hospitals surveyed using it as an oxygen source for the entire hospital.
The major limitation of oxygen concentrator is that its maximum flow output maybe less than the oxygen requirements during the peak hours of its use in the hospital.
In addition to the economic costs, a number of other issues must be considered. The process generates a great deal of heat; hence, ventilation and cooling for the product and the compressors are major considerations. Provision of easy access, cooling, and ventilation strategies are the essential aspects. The plant should be placed above the ground level to get advantage in case of natural disasters such as flood. At the same time, it should not be placed with other oxygen sources such as liquid oxygen or cylinder manifolds due to the risks posed by the heat production.
The boiling point of oxygen is −183°C and in vacuum insulated evaporator (VIE), it is kept at −160°C at 5–10 atmospheric pressure. This is much below its critical temperature of −118.4°C, the temperature above which no amount of pressure can hold oxygen in liquid state. At 15°C, one L liquid oxygen can lead to the production of 842 L of gas at one atmospheric pressure.
A typical-sized VIE contains 5000–10,000 L of liquid oxygen. A full 10,000 L tank of liquid oxygen could be approximately equal to 1200 “J” type cylinders of 7000 L. The purity, economical advantage in addition to the large capacity has made liquid oxygen the popular choice in almost all big hospitals. The downside is that liquid oxygen might be coming from distant sites making availability an issue during natural disasters.
There are liquid oxygen transport vehicles with incorporated super heaters so that liquid oxygen could be converted to gaseous oxygen in the vehicle itself and can be pumped to a disaster backup hook in a crisis.
The use of telemetry can be useful for both the hospitals and the vendors to monitor and initiate supply. [Table 2] suggests the days of oxygen stock needed depending on the distance from the liquid oxygen plant and availability of telemetry.
Location of the oxygen supply at hospital site
Considering natural disasters such as floods, location of oxygen should not be below ground level. In our survey, the hospitals with the concentrators in the ground floor get flooded. The option of installing the oxygen concentrators on higher floors or rooftop could be explored to avoid this obstacle to oxygen supply during a flood like scenario.
Entry of the pipelines to the hospitals was located at the same site in all the hospitals. Hence, any damage proximal to the entry site would affect the supply. Commonly, this happened after public works department (PWD) works. [Table 3] suggests the various combinations of primary, secondary, and reserve oxygen supply.
Adequate personnel should be trained and a committee including doctors, biomedical engineers, and other technicians should meet at regular intervals to evaluate the safe working of the system. A standard-operating procedure should be printed and kept in the control room and other predetermined areas. Everyone in the committee should be familiar with the working of the system down to last detail. Mock drills should be conducted to ensure the adequacy of support and failure systems. A designated area to monitor all failure alarm systems should be manned at all times. This area should have monitors for assessing the amount of gas remaining.
Changeover and alarm systems
Only 20% of hospitals had an automatic changeover system between the primary and reserve source. But of note, even the changeover between the banks of the primary cylinder manifolds was not automatic in most of the hospitals, thus inviting possibility of major human error. There should be dedicated visual and audible alarm systems for the medical gas supply with a central system in an area which is functional at all times, especially at gas supply technicians' office and maintenance section. Repeater panels in the appropriate areas such as the engineer's office should also be present. There should be area alarm panels in the areas downstream of the area valve service units (AVSUs). AVSUs are used to cut off the gas delivery to the area beyond it during maintenance as well as during an emergency. In our survey, only 12% of the hospitals had an efficient alarm system. However, there were no definite plans regarding response to alarm failures.
In case of any disaster situation, an urgent meeting of the gas supply committee should be convened to assess the available oxygen supply. Elective procedures requiring oxygen should be suspended until adequate external supply reaches. Assessment to determine the remaining time to end of supply should be done. In hospitals which have multiple separate blocks, the reserve supply could be limited to high-dependency areas. Inspection of the pipelines and mock drills of pipeline failure, fire, and explosion should be conducted routinely. Inspection of safety after the PWD, work of an area by the concerned personnel should be made mandatory and records of such inspection should be kept.
| Conclusion|| |
There are major lacunae in the safety of the oxygen supply systems across most hospitals, whether it is the source of oxygen, automatic change of supply, location or alarm systems. Many hospitals use bulk liquid oxygen or cylinder manifolds as their primary source of supply. However, most of the hospitals rely on a single pipeline from a particular location. This type of supply can be detrimental during disasters. A robust alarm system and a continuously manned gas supply room should be established to monitor oxygen supply and the alarm systems.
Contingency planning must be in place to reduce the risk of an uninterrupted supply. The presence of automatic changeover systems to a backup source with physically separated feed lines are imperative. Primary, secondary, and reserve supply should preferably involve the use of liquid oxygen, oxygen concentrators, or cylinder manifold systems in various combinations. Decisions should be made depending on the size of hospital, geographical location, proximity to a liquid oxygen plant, and risk assessments. An advisory has been mandatory regulations from statutory bodies in this matter. Awareness that this is an extremely crucial clinical aspect rather than just a technical safety issue could also bring about a positive change in the matter.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]