The Science Journal of the American Association for Respiratory Care

2004 OPEN FORUM Abstracts

EVALUATION OF SEASONAL PRESENCE OF CHLORINE (Cl) GAS IN AN URBAN HOSPITAL MEDICAL AIR SYSTEM

Jeffrey P. Natterman MA, RRT, Joseph G. Dwyer BS, RRT. The Johns Hopkins Hospital, Baltimore Maryland.

Introduction: During routine repair and maintenance of clinical equipment, discoloration of bronze filters from air inlet ports revealed sintered material suggesting possible contamination through the hospital medical air system. Chemical analysis by an Applied Physics Lab resulted in the presence of Chlorine bound to the copper in bronze. Chlorine is a known respiratory irritant in concentrations as low as 3 ppm, therefore the following procedure was implemented to detect, measure and assess the impact of chlorine in the hospital medical air system. The process for comparing levels based on differing seasons was a result of more frequent clinical equipment repairs being required following the summer months.

Methods: Twenty (20) samples were collected (10 in January, 10 in July) in four (4) liter (L) Teldar bags equipped with one-way valves. The samples were then passed through Draeger graduated ten-stroke chlorine cuvettes (by means of the Draeger calibrated hand pump) with the capacity to analyze the presence of chlorine in concentrations from 0.2 – 3.0 ppm. Absence of chlorine results in no color change from white in the cuvettes, presence of chlorine results in a color change to yellow/orange depending on the level of concentration.

Results:There was no detectable Chlorine from any of the 10 samples measured during the winter months, however, the summer month samples resulted in Chlorine levels ranging from 0.2 ppm – 1.0 ppm with a mean value of .48 ppm.

Conclusions: The measurable presence of Chlorine gas within the hospital medical air system is concerning enough to evaluate potential exposures and outcomes from a risk management standpoint. The low levels (and lack of Chlorine during specific time frames) invite investigation to determine source, seasonal activities and potential increases in future levels. Urban medical facilities, especially those with aging medical air systems frequently use water cooling mechanisms during air compression before introducing the gas into the hospital lines. Mechanical ventilators and air/oxygen blenders to deliver mixed gas to the patient population then use the water-cooled air. During summer months, especially during peak water usage, or drought conditions, river water is occasionally used to supplement reservoir use. The use of various water sources requires city water departments to use higher levels of chlorine to maintain acceptable standards for water purity. Continued monitoring and tracking for trends and spikes in concentrations could result in more informed management of systems, reduced cost for equipment repair and replacement, and above all a more educated approach to patient care delivery.

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